Digitized by the Internet Archive in 2009 with funding from Boston Library Consortium IVIember Libraries http://www.archive.org/details/cambrianbrachiopOOwalc DEPARTMENT OF THE INTERIOR MONOGRAPHS OF THE United States Geological Survey VOLUME LI r»art I.-TEXT DOCUMENTS DEPARTMENT RECEIVED JAM 2 196? WASHINGTON WUbui Cioss Libiaiy GOVERNMENT PRINTING OFFICE Univeisity of Connecticut 1912 UNITED STATES GEOLOGICAL SURVEY GEORGE OTIS SMITH, Director CAMBRIAN BRACHIOPODa BY CHARLES D. ¥^ALCOTT WASHINGTON GOVERNMENT PRINTING OFFICE 1912 CONTENTS. GENERAL SUMMARY OF THE MONOGRAPS. p^ ^ Acknowledgments "11 Bibliography 13 Synonymy, tabulated alphabetically by genera, subgenera, species, and varieties, with present references 27 Geographic and stratigraphic distribution, by species zoologically arranged 98 Geographic distribution, by continents, geologic provinces, and States or countries 114 Stratigraphic distribution by States or countries, with typical or general sections, correlating localities and fossils . 123 Habitat, alphabetic list of genera and subgenera, giving -data on 160 Localities, by number, -with lists of fossils and reference to position in stratigraphic tables 161 Terminology adopted for the monograph 291 Definitions or glossary 292 The shell, structural features : 296 Evolution, schematic diagram of, for all genera and subgenera 317 Classification, table and analysis - 321 Description of genera and species 327 CONTENTS IN DETAIL. Introduction - 11 Preparation and scope '. 11 Acknowledgments 11 Historical data ; 13 Bibliography 13 Synonymic references. , 1'^ List, by genera, subgenera, species, and varieties, of references in synonymy, with present reference of each. 27 Geologic data 98 General geographic and stratigraphic distribution : 98 Distribution by species , 98 General geographic and stratigraphic distribution of the Cambrian and Ordovician Brachiopoda. . 98 Summary of Cambrian Brachiopoda 110 Summary of Ordovician Brachiopoda 113 General summary of Cambrian and Ordovician Brachiopoda 113 Detailed geographic distribution. 114 Cambrian Brachiopoda 114 North American species 114 European species 120 Asiatic species 121 South American species 122 Australian species 122 Ordovician Brachiopoda ; \ 122 North American species '. 122 European species ■ 123 Detailed stratigraphic distribution of Cambrian and Ordoviciap Brachiopoda 123 Alabama • 124 Alberta 124 Arizona 124 Bohemia 124 British Columbia: Mount Bosworth ; 125 California 131 Cape Breton and New Brunswick 131 Colorado 135 Denmark 135 England, Scotland, and Wales , 135 Finland 136 Georgia , 136 Germany 136 Idaho 136 Iowa 136 Labrador 136 Maryland ..- 136 5 6 CONTENTS. Geolosjic data — Continued. Detailed stratigi-aphic distribution of Cambrian and Ordovician Brachiopoda — Continued. Page. Michigan 136 Minnesota - 136 Missouri 137 Montana and Wyoming 137 Nevada: Barrel Spring 137 Nevada: Eureka District 139 New Brunswick ■ 140 Kewfoundland : Manuels Brook, Conception Bay 140 New York 141 Norway 141 Nova Scotia 141 Oklahoma: Arbuckle Mountains 141 Ontario 143 . Pennsylvania 143 Quebec, Ontario, and Labrador - 143 Russia 143 Scotland 144 South Dakota and Wyoming 144 Sweden, Denmark, Finland, and Norway 144 Tennessee, Georgia, and Alabama - ' 147 Texas 148 Utah: Blacksmith Fork, Cache County ^ ■■ 148 Utah: House Range, Millard County 153 Vermont , 150 Virginia and Maryland 159 Wales 159 Wisconsin, Michigan, Minnesota, and Iowa. . 159 Wyoming - 150 Habitat _■ - - ■ - ■ ; - 159 List of genera and subgenera, alphabetically arranged, giving number of species occurring in the dif- ferent types of sediment 160 Localities 1"0 LocaUties 1-227, U. S. National Museum 161 Locahties 300-396z, arbitrarily numbered 229 LocaUties C1-C75, Carnegie Institution of Washington Expedition to China 286 Zoological discussion 291 Terminology 291 General statement 291 Definitions 292 The brachiopod shell 296 Structure 296 General statement. 296 Microscopic structure 297 Surface ornamentation — 300 General statement 300 Atremata - ^^^ Neotremata ^^^ Protremata ^^^ Interlocking plications 3""' Cardinal area • '^^^ Atremata ^^ Neotremata. 304 Protremata ^^^ Delthyrium and deltidium ^"^ Listrium '^"° Pseudochilidium ^'^^ Cardinal process Articulating processes *'"' SpondyUum ^^'^ CruraUum ^^^ Platform ^^^ Septa - 3^" Dental plates ^^^ CONTENTS. 7 Zoological discussion — Continued. Tlie brachiopod shell — Continued. Page. Vascular markings 1 311 Atremata 311 Neotremata 311 Protremata 311 Muscle scars - 312 Atremata 312 Neotremata 312 Protremata 313 Pedicle tube and aperture 314 ' Atremata 314 Neotremata 314 Protremata 315 Old-age characters 315 Distribution in Cambrian strata 315 Evolution of the Cambrian Brachiopoda 316 Schematic diagram .' 316 Atremata 318 Neotremata 319 Protremata 319 Classification - 321 Order Atremata 322 Superfamily Rustellacea .' 322 Family Rustellidae 322 Family Paterinidaj 322 Superfamily Obolacea 322 Family Curticiidee 322 Family Obolidfe 322 Subfamily Obolinse 322 Subfamily Elkaniinse 323 Subfamily Neobolinae 323 Subfamily Biciinse 323 Superfamily Kutorginacea 323 Family Kutorginidae 323 Family Schuchertinidse 323 Order Neotremata 323 Superfamily Siphonotretacea 324 Family Obolellidae 324 Family Siphonotretidte 324 Superfamily Acrotretacea 324 Family Acrotretidffi 324 Subfamily Acrothelinse 324 Subfamily Acrotretinas ^ 324 Superfamily Discinacea 325 Family Discinidte 325 Superfamily Craniacea 325 Family Craniidse 325 Order Protremata 325 Superfamily Orthacea 325 Family Billingsellidse , .325 Subfamily Nisusiinse 325 Subfamily Billingsellinse , 325 Subfamily Eoorthinse '. 326 Superfamily Strophomenacea 326 Family Strophomenidse ; 326 Subfamily Rafinesquinse 326 Superfamily Pentameracea _. 326 Family Syntrophiidae 326 Description of genera and species " -. 327 Rustella Walcott : 327 Mickwitzia Schmidt 329 o The list ot species on pp. 98-109 gives the names of all the species in the order in which they appear in the monograph and also not only the page but the illustration reference and other information. It should therefore be of more value to the student than a merelist of speciesin these ' contents, and such a list has accordingly been omitted. The pages upon which the genera and subgenera are described are not shown in the list on pp. 98-109; therefore these are shown here. 8 CONTENTS. Description of genera and species — Continued. Paee Micromitra Meek 332 (Paterina) Beecher 343 (Iphidella) Walcott 359 Volborthia von Moller 355 Helmersenia Pander 357 Curticia Walcott 3g9 Obolus Eichwald 37O (Broggeria) Walcott , 424 (Palaeobolus) Matthew 426 (Pordinia) Walcott 428 (Lingulobolus) Matthew ^ 43O (Mickwitzella) Walcott 434 ( Acritis) Volborth 437 (Schmidtia) Volborth 441 (Westonia) Walcott 45O Lingulella Salter .- 468 (Leptembolon) Mickwitz..". 54I (Lingulepis) Hall 544 Delgadella Walcott 560 Elkania Ford 561 Neobolus Waagen 554 Bicia Walcott 568 Dicellomus Hall 57I Kutorgina Billings • , _ _ _ 579 Schuchertina Walcott 585 Obolella Billings 586 (Glyptias) Walcott , 599 Botsfordia Matthew 601 Schizopholia Waagen 608 Quebecia Walcott 609 Yorkia Walcott 611 Dearbornia Walcott _ 614 Trematobolus Matthew 615 Schizambon Walcott 622 Siphonotreta de Verneuil , 624 Keyserlingia Pander 628 Acrothele Linnarsson 630 (Redlichella) Walcott 662 Discinolepis Waagen 664 Linnarssonella Walcott ■ 665 Acrotreta Kutorga 671 Acrothyra Matthew 715 Discinopsis Matthew 720 Orbiculoidea d'Orbigny ". 722 Philhedra Koken 724 Nisusia Walcott 725 (Jamesella) Walcott 731 Protortliis Hall and Clarke ., 738 (Loperia) Walcott 744 Wimanella Walcott 745 Billingsella Hall and Clarke 749 Orusia Walcott : 765 Otusia Walcott '. 769 Wynnia Walcott ' 77I Eoorthis Walcott 772 Finkelnburgia Walcott ; 793 Eostrophomena Walcott _ . 795 Swantonia Walcott ' 796 Syntrophia Hall and Clarke 798 Huenella Walcott 805 Clarkella Walcott 809 ILLUSTRATIONS. Page. PlatesI-CIV P*'"\" Figure 1. Billingsella plicatella 2. Dalmanella subequata OQQ 3. Kutorgina cingulata - - 4. Obolus apollinis ^^^ ■ 9QQ 5 Billingsella coloradoensis - 299 6. Nisusia festinata 299 7. Eoorthis remniclia 299 8. Kutorgina cingulata - 9 Dalmanella multisecta 299 10. Dalmanella parva - 299 11. Syntrophia lateralis ^° 12. Plectorthis plicatella . 299 13. Huenella abnormis 299 14. Obolella crassa 15. Obolus apollinis ^99 16. Dicellomus politus 17. Diagram illustrating known distribution of families in Cambrian strata - 316 18. Schematic diagram of evolution of Cambrian BracMopoda 317 19. Rustella? major ^^ 20. Micromitra haydeni ^^^ 21. Micromitra scotica ^ 22. Micromitra sculptilis endlichi 23. Micromitra zenobia 24. Micromitra (Paterina) labradorica utahensis. \ ^50 25. Micromitra (Paterina) major 26. Micromitra (Paterina) stuarti .- -. ^^^ 27. Micromitra (Paterina) superba ^'^^ 28. Micromitra (Paterina) undosa ■' ^^^ 29. Micromitra (Paterina) wapta •- 30. Micromitra (Paterina) williardi - ^^^ 31. Micromitra (Iphidella) louise - - - - - ^59 32. Micromitra (Iphidella) pannula - 362 33. Volborthia recurva ; ^^^ 34. Interiors of valves of Obolus apollinis quenstedti and Lingula anatina 374 35. Obolus dolatus ^^'^ 36. Obolus membranaceus - 37. Obolus parvus - ^^^ 38. Obolus smithi ; - - ^■'■^ 421 39. Obolus wortheni • ^ ^ 40. Obolus (Westonia) dartoni - ^^^ 41. Obolus (Westonia) wasatchensis ; ^°' i2. Lingulella clarkei ^^^ Kin 43. Lingulella isse '^■^" 44. Lingulella triparilis. 45. Lingulella zeus ; 46. Lingulella (Lingulepis) acuminata sequens. 551 47. Neobolus warthi ^^^ 48. Dicellomus pectenoides ' 49. Dicellomus politus • 50. Kutorgina cingulata ■ - 51. Obolella atlantica °^° 52. Obolella groomi - 9 10 ' ILLUSTRATIONS. Page. Figure 53. Obolella vermilionensis 598 54. Acrothele artemis 634 55. Acrotiele colleui 641 56. Acrotreta cariuata 680 57. Acrotreta circularis 680 58. Acrotreta kutorgai 692 59. Acrothyra minor T , 717 60. Nisusia rara 730 61. Nisusia (Jamesella) lowi 734 62. Nisusia (Jamesella) spencei 737 63. Wimanella inyoensis 747 64. Wimanella simplex 748 65. Billingsella bivia 750 66. Billingsella coloradoensis 751 67. Billingsella marion 758 68. Wynuia warthi , 771 69. Eoorthis newberryi 783 70. Eoorthis thyone 789 71. Eoorthis zeno 792 72. Syntrophia cambria 800 73. Syntrophia campbelli 801 74. Syntrophia ? unxia 805 75. Huenella lesleyi 807 76. Huenella vermontana 809 CAMBRIAN BRACHIOPODA. By Charles D. Walcott. INTRODUCTION. PREPARATION AND SCOPE. It was not until aft°r the preparation of the prehminary memoir on the fauna of the Lower Cambrian or Olenellus zone« that I began to tliink seriously of undertaking the systematic study of the Cambrian faunas of the world. The second extended contribution was the memoir on the fossil Medusae/ after wliich studies were continued on the Braclnopoda. Administra- tive duties have greatly interfered with the prosecution of the work, but by taking advantage of aU opportunities, both in the field and office, some progress has been made from year to year The work is not so complete as it mi'ght be in its discussion of genera and species, details of evolution and the relations of the Cambrian bracliiopod fauna to Ordovician and later faunas My main purpose has been to make the results of the investigation of value to the student of Cambrian faunas and to the stratigraphic geologist. This monograph includes the description of 44 genera, 15 subgenera, 477 species, and 59 varieties of Cambrian Brachiopoda, and of 3 genera, 1 subgenus, 42 species, and 1 variety of Ordovician Brachiopoda. Of the Cambrian forms, 10 genera, 2 subgenera, 21 species, and 1 variety persist into the Ordovician. (See pp. 98-113 for complete tables giving distribution.) lA this paper the Bracliiopoda are treated in three ways— historically, geologically, and zoologically. Historically the treatment comprises (1) a bibhography and (2) a table of synonymic reference, giving a completely cross-referenced Hst of described species with the present generic and specific reference of each. Geologically the distribution of the Brachi- opoda is considered under the following headings: (1) General geographic and stratigraphic distribution; (2) detailed geographic distribution; (3) detailed stratigraphic distribution; (4) habitat; and (5) fossil locahties. Zoologically the discussion covets (1) the physical characters of the Brachiopoda; (2) their distribution; (3) their evolution; and (4) their classification. Lastly come the detailed descriptions of genera and species and the illustrative plates. ACKNOWLEDGMENTS. In the course of the investigations of the Cambrian brachiopods during the past ten years I have received assistance m various forms and degrees from many individuals in all sections of the world where the Cambrian strata and faunas occur. To all I return my most grateful acknowledgment and sincere thanks. If any who have assisted me are overlooked m these acknowledgments, I beg leave to assure them that it is not by intention. Dr. Ferdinand Schmidt, of the Royal Institution of St. Petersburg, sent many specimens and valuable notes on the range of the species in the Upper Cambrian and Lower Ordovician beds of the Baltic provinces of Russia. j ^ t? Dr. A. Mickmtz, of Reval, Esthonia, Russia, sent material from the Oholus beds of Russia. a Walcott, C. D., Fauna of the Lower CamDrian or Olenellus zone: Tenth Ann. Rept. U. S. Geol. Survey, pt. 1 1890, pp. 509-763. 6 Walcotti C. D,, FossU Medusa: Men. U. S. Geol. Survey, vol. 30, 1898. 12 CAMBRIAN BRACHIOPODA. Mr. J. F. Nery Delgado, of the Geological Survey of Portugal, presented photographs of several of the Lower Cambrian brachiopods described by him from Portugal, also a specimen of the new form Delgadella lusitanica. Dr. Charles Barrois, of the University of Lille, France, gave information in relation to the Cambrian faunas of Spain and France. Dr. Karl A. Gronwall, of the Geological Survey of Denmark, made a collection of Cambrian fossils for me in Bornholm, among which were fine representatives of the brachiopods described by liim in his memoir on the Paradoxides fauna of Bornholm. Dr. J. F. Pompeckj, of the University of Hohenheim, Wurttemberg, Germany, was always ready to give information and assistance. Dr. T. H. Holland, director of the Geological Survey of India, generously loaned for study the collection of brachiopods from the Cambrian formations of the Salt Range, and gave me the opportunity of studying and illustrating Doctor Waagen's types. Prof. Walter Howcliin, of the University of Adelaide, South Australia, sent for study and illustration all the types of Cambrian fossils described by Messrs. R. Etheridge, jr., and Ralph Tate. As a result of the expedition of the Carnegie Institution of Washington to China under the direction of Mr. Bailej'- Willis, assisted by Mr. Eliot Blackwelder, large collections of fossils were made from many faunal horizons of the Cambrian, and among them the various brachio- pods described in this volume. i Dr. W. C. Brogger, of the University of Christiania, Norway, very generously loaned the types described by him in "Die Silurischen Etagen 2 und 3," also duphcate material of Cam- brian bracliiopods which he had collected at various localities in Norway. Dr. N. Olof Hoist, of the Geological Survey of Sweden, very Idndly took charge of the making of collections of Cambrian fossils for me by Mr. G. Schmalensee, a collector of the Survey, and also permitted the sending of specimens for study and in exchange. Dr. Joh. Chr. Moberg, of Lund, Sweden, both loaned and presented material for study. Through the courtesy of Dr. Carl Wiman, of Upsala, Sweden, I had the opportunity of studying the Cambrian brachiopods described by him from the North Baltic region. He not only sent me the specimens, but also answered inquiries in relation to certain facts concerning them which did not appear in the text of his report. I am greatly indebted to the Geological Survey of Canada for the loan of many of the types in the collections of the Survey museum. Prof. J. F. Wliiteaves and Dr. Henry M. Ami were especially kind in selecting and forwarding the specimens desired. Sir William E. Dawson permitted me to look over the collection of the McGill Uni- versity museum, and later Dr. Frank D. Adams sent specimens of the Cambrian brachiopods in the collection. For many years before the sale of his collection. Dr. George F. Matthew, of St. John, New Brunswick, frequently loaned me his types and study material, and also when I visited New Brunswick directed me to the most favorable locahties for collecting material both ia New Brunswick and Cape Breton. When liis collections went to the Universitj^ of Toronto, Prof. W. A. Parks sent to me from them the various types that I needed for study and illus- tration. Prof. Alexander Agassiz permitted me to study the collections of Cambrian brachiopods in the Museum of Comparative Zoology, and also to take to Washington and have illustrations made of a number of specimens, especially those from Bohemia. Prof. J. M. Clarke, director of the New York State Museum, Albany, N. Y., was most courteous in lending material and giving information relating to it. Mr. W. A. Finkelnburg, of Winona, Minn., sent material from his collection, and also made collections from the "St. Croix sandstone" at several localities in Minnesota which enabled me to add very materially to the description of the Cambrian brachiopods of Minnesota. Prof. Alpheus Hyatt, of the Boston Museum of Natural History, lent material he collected on the coast of Labrador, and he was always ready to discuss problems connected with the life history and evolution of the Brachiopoda. BIBLIOGRAPHY. < 13 To no one am I more indebted than to Prof. Charles Schuchert, of Yale University, whose suo-gestions and comments, made in response to questions submitted to him, and also as the result of examining the plates and the preUminary draft of the zoological discussion, have been most helpful. From year to year material for study was brought in by various members of the United States Geological Survey as opportunity offered, and large collections were made in the Cor- dilleran area of the United States by Mr. S. Ward Loper, of the Wesleyan University museum. I collected personally from various parts of the United States and Canada, England, and Wales, being assisted in the Cordilleran area by Mr. F. B. Weeks and Mr. Lancaster D. Burling. During the course of the preparation of this monograph I have received from time to time effective assistance from members of the United States Geological Survey, especially those directly acting as my assistants. When studying the Acrotretidte Dr. George H. Girty selected material for illustration and also made preliminary notes on some of the species. Miss Elvira Wood separated and classified the bracluopods collected in 1905-6, directed the preparation of drawings, and, in 1906, revised the proof of the plates, which were printed at that time. Mr. Lancaster D. Buriing, of the United States National Museum, revised, verified, and tabulated the synonymy and locaHties and assisted in many ways in the final make-up of the text of the volume. from 1907 to 1912. At my request Mr. E. O. Ulrich, of the United States Geological Survey, carefully read the zoological discussion and made notes that led me to make several modifications, especially in relation to the protrematous genera. I have included in the text his observations on the spondylium. To Mr. R. S. Bassler, of the United States National Museum, I am indebted for a number of thin sections of the shells of Cambrian brachiopods and a few Ordovician orthoids and for notes on the sections. The drawings have been prepared mainly by Miss Frances Wieser, of the United States Geological Survey. The plates are the evidence of her faitMul work'. HISTORICAL DATA. BIBLIOGRAPHY. The following bibUography includes the works referred to in this monograph," arranged alphabetically by authors and chronologically under each author: Ami, H. M.: 1887. The Ottawa Naturalist, vol. 1, No. 9, 1887 (Dec), pp. 121-126; Notes on, and the precise geological horizon of, Siphonotreta scotica Davidson. Barrande, J. (see also DB Verneuil and Barrande): 1848. Naturwissenachaftliche Abhandlungen, gesammelt und durch Subscription herausgegeben von WiUielm Haidinger, Bd. 2, Abth. 1, No. 5, 1848, pp. 153-2.56: Ueber die Brachiopoden der silurischen Schichten von Bobmen. 4°. Wien. 1868a. II: Faune silurienne des environs de Hof, en Bavifere, 1868 (Dec), pp. 31-110 (published with I: Reap- parition du genre Arethusina Barrande.) 8°. Prague. 1868b. Neues Jahrbuch fiir Mineralogie, Geologic, und Palseontologie for 1868, pp. 641-696: Silurische Fauna aus der Umgebung von Hof in Bayern. 1879a. Systdme silurien du centre de la Boheme, vol. .5, pt. 1, 1879, pp. 1-226, Pis. I-LXXI. 4°. Prague. • 1879b. Systeme'silurien du centre de la Bohgme, vol. 5, pt. 1, 1879, Pis. LXXII-CLIII. 4=. Prague. Barrois, C: 1882. Memoires de la Soci^te geologique du Nord, tome 2, Mem. 1, 1882; Recherches sur les terrains anciens des Asturies et de la Galice (Espagne). Bassler, R. S.: The lists of phyllopods cited under several of the localities on pages 161 to 291 were furnished to me by Mr. Bassler from a manuscript copy of Ulrich and Bassler's memoir on the Phyllopoda, which is now in press. Beecher, C. E.: 1891. American Journal of Science, 3d ser., vol. 41, 1891 (April), pp. 343-357; Development of the Brachiopoda. ..Exceptions are: Albers, p. 434; Balsamo-Crivelli, p. 441; Baly, pp. 332 and 334; Clarke, p. 441; Iddingsand Weed, p. 417; Marshall, pp. 434 and 441; and Stose, p. 271. 14 CMIBKIAN BKACHIOPODA BiGSBY, J. J.: 1S68. Thesaurus Siluricus: The flora and fauna of the Silurian period, with addenda, 1868. 4°. London. Billings, E.: 1856. The Canadian Naturalist and Geologist, 1st ser., vol. 1, 1856 (Feb.), pp. 32-39: Fossils of the Potsdam sandstone. 1857. Geological Survey of Canada, Report of progress for the years 1853-1856, 1857, pp. 247-345: Report of paleontologist for 1856. 1859. The Canadian Naturalist and Geologist and Proceedings of the Natural History Society of Montreal, 1st ser., vol. 4, No. 6, 1859 (Dec), pp. 426^70: Fossils of the Chazy limestone, with descriptions of new species. 1861a. The Canadian Naturalist and Geologist, 1st ser., vol. 6, No. 4, 1861 (Aug.), pp. 310-328: On some of the rocks and fossils occurring near Phillipsburg, Canada East. 1861b. Geological Survey of Canada, Paleozoic fossils, vol. 1, 1861 (Nov.), pp. 1-24. 1861c. Report on the geology of Vermont, vol. 2, 1861, pp. 942-960, appendix: On some new or little known Lower Silurian fossils from the Potsdam group (Primordial zone). 4°. Claremont, New Hampshire. 1862a. Geological Survey of Canada: Paleozoic fossils, vol. 1, 1862 (Jan.), pp. 25-56. 1862b. The American Journal of Science and Arts, 2d ser., vol. 33, 1862 (May), pp. 100-105: Further observations on the age of the Red sand-rock formation (Potsdam group) of Canada and Vermont. 1862c. The American Journal of Science and Arts, 2d ser., vol. 33, 1862 (May), pp. 420-421: On the date of the recently published report of the superintendent of the Geological Survey of Wisconsin, exhibiting the progress of the work, Jan. 1, 1861. 1862d. Geological Survey of Canada, Paleozoic fossils, vol. 1, 1862 (June), pp. 57-168. I 1862e. Report on the economical geology, physical geography, and scenery of Vermont, by A. D. Hager, 1862, pp. 214-227, appendix: On some new or little known species of Lower Silurian fossils from the Potsdam group (Primordial zone). 4°. Claremont, New Hampshire. 1863. Fifteenth report of progress. Geological Survey of Canada, from its commencement to 1863, 1863. 1865a. Geological Survey of Canada, Paleozoic fossils, vol. 1, 1865 (Feb.), pp. 169-344. 1865b. Geological Survey of Canada, Paleozoic fossils, vol. 1, 1865 (Oct. ?), pp. 345-426. 1868. Acadian geology, by J. W. Dawson, 2d ed., 1868, p. 643: Description of Eocystites primxvus. 1872a. The Canadian Naturalist and Quarterly Journal of Science, new (2d) ser., vol. 6, No. 2, 1872, pp. 213-222: On some new species of Paleozoic fossils. 1872b. The Canadian Naturalist and Quarterly Journal of Science, new (2d) ser., vol. 6, No. 4, 1872, pp. 465^80: On some fossils from the Primordial rocks of Newfoundland. 1872c. The American Journal of Science and Arts, 3d ser., vol. 3, 1872 (May), pp. 352-360: On some new species of Paleozoic fossils. 1874. Geological Survey of Canada, Paleozoic fossils, vol. 2, pt. 1, 1874 (Aug.). ■ 1876. The American Journal of Science, 3d ser., vol. 9, 1876 (Mar.), pp. 176-178: On the structure of Oholella chromatica. 1882. Geological Survey of Newfoundland, Report of progress for 1881, 1882, appendix. Blackwelder, Eliot (see also Willis and Black welder): 1907a. Carnegie Institution of Washington, Research in China, vol. 1, 1907 (Apr.), chap. 2, pp. 19-58: Stratig- raphy of Shan-tung. 1907b. Carnegie Institution of Washington, Research in China, vol. 1, 1907 (Apr.), chap. 12, pp. 265-279: Stratig- raphy of the Middle Yang-tzi Province. Blochmann, Fr.: 1900. Untersuchungen iiber den Bau der Brachiopoden, pt. 2: Die Anatomie von Disdnisca lamellosa (Broderip) und Lingula ariatina Bruguiere, mit einem Atlas, 1900. 4°. Jena. BORNEMANN, J. G.: 1891. Nova Acta Academies Csesarese Leopoldino-Carolinse Germanicse Naturae Curiosorum, Bd. 56, No. 3, 1891: Die Versteinerungen des cambrischen Schichtensystems der Insel Sardinien, Abth. 2. Brogger, W. C: 1878. NytMagazin for Naturvidenskabeme, Bd. 24, Hft. 1, 1878, pp. 18-88: On paradoxidesskifrene ved Krekling. 1882. Die silurisehen Etagen 2 und 3 im Kristianiagebiet und auf Eker, etc., 1882. 4°. Christiania. BucH, C. L. von: 1834. Physikalische Abhandlungen der Koniglichen Akademie der Wissenschaften zu Berlin, 1834. 1841. Archiv fiir Mineralogie, Geognosie, Bergbau, und Hiittenkunde, Bd. 15, Hft. 1, Abh. 1, No. 1, 184], pp. 1-128: Beitrage zur Bestimmung der Gebirgsformationen in Russland. BIBLIOGRAPHY. 15 « Burr, H. T.: 1900. The American Geologist, vol. 25, 1900 (Jan.), pp. 41-50: A new Lower Cambrian fauna from eastern Massa- chusetts. Callaway, C. : 1874. The Quarterly Journal of the Geological Society of London, vol. 30, pt. 1, 1874, p. 196: On the occurrence of a Tremadoc area near the Wrekin in South Shi'opshire, with description of a new fauna. 1877. The Quarterly Journal of the Geological Society of London, vol. 33, pt. 1, 1877, pp. 652-672: On a new area of Upper Cambrian rocks in South Shropshire, with a description of a new fauna. Campbell, M. R.: 1899. Bristol (Virginia-Tennessee) folio (No. 59), Geologic Atlas United States, United Stat3s Geological Survey, 1899. Carpenter, W. B.: 1853. A monograph of the British fossil Brachiopoda, by Davidson, vol. 1, introduction, No. 2, 1853 (Dec), pp. 23^5: On the intimate structure of the shells of Brachiopoda. 4°. London. Chapman, E. J.: 1863. The Canadian Journal of Industry, Science, and Art; conducted by the editing committee of the Canadian Institute, new ser., vol. 8, 1863 (Mar.-Sept.), pp. 111-127, 185-216, 437^62: A popular exposition of the minerals and geology of Canada. 1864. A popular and practical exposition of the minerals and geology of Canada, 1864. 8°. Toronto. Clark, W. B., and Mathews, E. B.: 1906. Maryland Geological Survey, vol. 6, pt. 1, 1906, pp. 29-259: The physical features of Maryland. Clarke, J. M. (see also Hall and Clarke): 1902. Bulletin New York State Museum No. 52, Report of the state paleontologist for 1901; 1902, pp. 606-615: A new genus of Paleozoic brachiopods, Eunoa, etc. Conrad, T. A.: 1839. Thu-d Annual Report New York State Survey -(printed as New York State Assembly Document No. 275), 1839 (Feb. 27), pp. 57-66: Second Annual Report of T. A. Conrad. Crane, Agnes; 1895. Geological Magazine, new ser., decade 4, vol. 2, 1895 (Feb.), pp. 65-75, 103-116: The evolution of the Brachiopoda (A sequel to Dr. Thomas Davidson's "What is a brachiopod?"). CuinNGS, E. R.: 1903. The American Journal of Science, 4th ser., vol. 15, 1903 (Jan.), pp. 1-136: The morphogenesis of Platy- ,strophia. A study of the evolution of a Paleozoic brachiopod. Dall, W. H.: 1870. American Journal of Conchology, new (2d) ser., vol. 6, pt. 2, 1870 (Oct. 6), pp. 88-168: A revision of the Terebratulidae and Lingulidse, with remarks on and descriptions of some recent forms. 1877. Bulletin United States National Museum No. 8, 1877, pp. 1-88: Index to names applied to subdivisions of the Brachiopoda. Dalman, J. A.: 1828. Kongl. Vetenskaps-Academiens Handlingar for 1827; 1828, pp. 83-155: Uppstallning och Beskrifning af de i Sverige funne Terebratuliter. Davidson, T.: 1853. 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Proceedings of the United States National Museum, vol. 3, 1880 (May 6), p. 47: Note on Acrothele. Whiteaves, J. F.: 1878. The American Journal of Science and Arts, 3d ser., vol. 16, 1878 (Sept.), pp. 224-226: On some Primordial fossils from southeastern Newfoundland. Whitfield, R. P. (see also Hall and Whitfield): 1862. The American Journal of Science and Arts, 2d ser., vol. 34, 1862 (July), p. 136: Note on the description of Lingula polita. 1875. Report of a reconnaissance of the Black Hills of Dakota, made in 1874, by William Ludlow, 1875, pp. 103- 104: Descriptions of new fossils. 1877. United States Geographical and Geological Survey of the Rocky Mountain Region: Report on the geology of the Black Hills of Dakota, Preliminary Report, 1877. 1878. Annual Report of the Wisconsin Geological Survey for 1877; 1878, pp. 50-89: Preliminary descriptions of new species of fossils from the lower geological formations of Wisconsin. 1880. United States Geographical and Geological Survey of the Rocky Mountain Region; Report on the geology and resources of the Black Hills of Dakota, by Newton and Jenney, 1880, pp. 329-468: Paleontological report. 1882. Geology of Wisconsin, vol. 4, 1882, pt. 3, pp. 161-363: Paleontology 1884. Bulletin of the American Museum of Natural History, vol. 1, No. 5, 1884 (Feb. 13), pp. 139-154: Notice of some new species of Primordial fossils in the collections of the museum, and corrections of previously described species. 1886. Bulletin of the American Museum of Natural History, vol. 1, No. 8, 1886 (Dec. 28), pp. 293-345: Notice of geological investigations along the eastern shore of Lake Champlain, with descriptions of new fossils. Willis, Bailey, and Blackweldee, Eliot: « 1907. Carnegie Institution of Washington. Research in China, vol. 1, 1907 (Apr.), chap. 6, pp. 99-152: Stratigra- phy of western Chili and central Shansi. Wiman, C: 1902. Bulletin of the Geological Institution of the University of Upsala, vol. 6, pt. 1, No. 11, 1902, pp. 12-76: Studien iiber das nordbaltische Silurgebiet. Winchell, a.: 1864. The American Journal of Science and Arts, 2d ser., vol. 37, 1864 (Mar.), pp. 226-232: Notice of a small collection of fossils from the Potsdam sandstone of Wisconsin and the Lake Superior sandstone of Michigan. Winchell, N. H.: 1886. Fourteenth Annual Report of the Geological and Natural History Survey of Minnesota for 1885; 1886, pp. 313-318: New species of fossils. Winchell, N. H., and Schdchert, C: 1895. The Geological and Natural History Survey of Minnesota, The geology of Minnesota, vol. 3, pt. 1, Paleon- tology, 1895, pp. 333-474: The Lower Silurian Brachiopoda of Minnesota. Wysogorski, Johann: 1900. Zeitschrift der deutschen geologischen Gesellschaft, Bd. 52, Hft. 2, 1900, pp. 220-226: Zur Entwicklungs- geschichte der Orthiden im ostbaltischen Silur. Zittel, K. a. von: 1880. Handbuch der Palaeontologie, Bd. 1, Palasozoologie, Abth. 1, 1880. 8°. Miinchen und Leipzig, o Since this reference was made and used in the monograph it has been noticed that the section on the Paleozc'o (pp. 136-152) is credited to Blackwelder. CA^IBEIAN BRACHIOPODA. 27 SYNONYMIC REFERENCES. The following table contains, arranged alphabetically by genera, subgenera, species, and varieties, a Ust of the Brachiopoda referred to in this monograph, as they occur in the Htera- ture, and gives the present reference of each: List, by genera, subgenera, species, and varieties, of the references given in the synonymy, with the present reference of each. A. Present reference. abavia [Acrothele], Matthew [1902b, pp. 398^00] Acrothele avia. Matthew [1903, pp. 100-101] Do. abnormis [Syntrophia], Walcott [1905a, pp. 289-290] Huenella abnormis. acadica [Obolus], Walcott [1905a, pp. 324-325]. : Obolus acadicus. Acritis Dall [1877, p. 11] Obolus (Acritis). Oehlert [1887, p. 1264] ". . . Do. Volborth [1869, pp. 212-217] Do. (Acritis) [Obolus], Mickwitz [1896, pp. 205-206] Do. Walcott [1901, p. 683] Do. Walcott [1908e, PI. XI, and pp. 142 and 144] Do. Acritis antiquissima Gagel [1890, p. 22] Obolus (Acritis) antiquissimus. Hall and Clarke [1892c, p. 82] Do. Volborth [1869, pp. 212-217] Do. (Acritis) antiquissimus [Obolus], Mickwitz [1896, pp. 206-213] Do. (Acritis) antiquissimus ventrosus [Obolus], Mickwitz [1896, pp. 213-214].. Do. (Acritis?) rugatus [Obolus], Walcott [1901, p. 694] Obolus (Acritis?) rugatus. Acrothele Davidson [1883, pp. 213-214] Acrothele. Grabau and Shimer [1907, p. 200] Do. Hall and Clarke [1892a, pp. 249-250] Do. Hall and Clarke [1892b, pp. 565-566] Do. Hall and Clarke [1892c, pp. 98-101] Do. Linnarsson [1876, pp. 20-21] Do. Matthew [1903, pp. 103-105] Do. Oehlert [1887, pp. 1269-1270] Do. Walcott [1886b, pp. 107-108] Do. Walcott [1908e, PI. XI, and pp. 142 and 146] Do. Zittel [1880, p. 665] Do. Acrothele aba^-ia Matthew [1902b, pp. 398-400] Acrothele avia. Matthew [1903, pp. 100-101] / Do. Acrothele artemis Walcott [1908d, p. 82] - Acrothele artemia. Acrothele avia Matthew [1899b, pp. 202-203] - Acrothele avia. Matthew [1902b, pp. 396-398] Do. Matthew [1903, pp. 55 and 98-99] Do. Acrothele avia-puteis Matthew [1902b , p . 398] Acrothele avia puteis . Matthew [1903, p. 100] Do. Acrothele barbata Moberg and Segerberg [1906, pp. 67-68] Acrothele ceratopygarum. Acrothele bellapunctata Walcott [1908d, pp. 82-83] Acrothele bellapunctata. Acrothele bellula Walcott [1897b, pp. 716-717] Acrothele bellula. Acrothele bergeroni Walcott [1908d, pp. 83-84] Acrothele bergeroni. Acrothele bohemica Hall and Clarke [1892c, p. 101] Acrothele bohemica. Pompeck] [1896b, pp. 509-511] Do. Walcott [1886b, p. 107] Do, Acrothele borgholmensis Walcott [1908d, pp. 84-85] Acrothele borgholmensis. Acrothele ceratopygarum Moberg and Segerberg [1906, p. 67] Acrothele ceratopygarum. Acrothele ceratopygonum Walcott [1902, p. 598] Do. Acrothele coUeni Walcott [new] Acrothele coUeni. . . Acrothele coriace Brogger [1878, p. 76] Acrothele coriacea. Acrothele coriacea Gronwall [1902, p. 40] Do. Linnarsson [1876, pp. 21-23] Do. Acrothele decipiens Walcott [1897b, p. 716] .Acrothele decipiens. Acrothele? dichotoma Walcott [1884b, pp. 14-15] Acrothele dichotoma. Acrothele gamagei Grabau [1900, pp. 615-617] Acrothele gamagei. Grabau and Shimer [1907, p. 200] Do. Shimer [1907, pp. 176 and 177] : Do. 28 CAMBRIAN BRACHIOPODA. Present reference. Acrothele granulata Davidson [1883, p. 214] Acrothele (Redlichella) granulata. Hall and Clarke [1892c, pp. 100-101] Do. Linnarsson [1876, p. 24] Do. Linnarsson [1877, pp. 373-374] Do. Swanston [1877, PL VII, fig. 20a-c] Do. Swanston [1886, PI. VII, fig. 20a-c] Do. Walcott [1886b, p. 109] Do. Acrothele inchoans Matthew [1902b, p. 404] Acrotreta inchoans. Matthew [1903, p. 103].... Do. Acrothele intermedia Gronwall [1902, p. 39]. . . : Acrothele intermedia. Linnarsson [1879, pp. 25-27] Do. Acrothele levisensis Walcott [1908d, p. 85] Acrothele levisensis. Acrothele matthewi Grabau and Shimer [1907, p. 200, fig. 234f] Acrothele matthewi. Grabau and Shimer [1907, p. 200, fig. 234g] Acrothele prima. Hall and Clarke [1892a, PL III, fig. 24] Acrothele matthewi. Hall and Clarke [1892c, pp. 99 and 100] Do. Matthew [1886, pp. 39^1] Do. Matthew [1895a, p. 128] , Do. Matthew [1902b, pp. 397 and 402] Do. Matthew [1903, p. 104] Do. Walcott [1884a, p. 15] Do. Walcott [1886b, p. 109] Do. Walcott [1891a, p. 609] Do. Acrothele matthewi costata Matthew [1895a, p. 128] Acrothele prima costata. Matthew [1902b, p. 397] :... Do. Matthew [1903, p. 104] Do. Acrothele matthewi eryx Walcott [1905b, p. 11] Acrothele matthewi eryx. Acrothele matthewi lata Hall and Clarke [1892a, PL III, figs. 25 and 26] . .Acrothele matthewi lata. Hall and Clarke [1892c, PL III, figs. 26-28] Do. ■ Matthew [1886, p. 41] Do. Matthew [1895a, PL V, figs. 8a-b] Do. Matthew [1903, p. 104] Do. Acrothele matthewi multicostata Matthew [1897b, p. 168] Acrothele matthewi multicostata. Acrothele matthewi prima Hall and Clarke [1892a, PL III, fig. 27] Acrothele prima. Hall and Clarke [1892c, PL III, fig. 25] Do. Matthew [1886, p. 41] .- Do. Matthew [1895a, PL V, figs. 7a-bi Do. Matthew [1902b, pp. 397 and 402] Do. Matthew [1903, p. 104] Do. Acrothele? minuta Walcott [1905a, p. 303] Acrothele? minuta. Acrothele panderi Walcott [new] Acrothele panderi. . Acrothele pretiosa Walcott [1898b, p. 402] : . Acrothele pretiosa. Acrothele primseva Pompeckj [1896b, p. 603] Acrothele primseva. Acrothele proles Matthew [1902b, pp. 400^01] Acrothele proles. Matthew [1903, pp. 60 and 102-103] Do. Acrothele quadrilineata Pompeckj [1896b, p. 511] Acrothele quadrilineata. Acrothele rarus Walcott [1905a, pp. 303-304] - - - - Acrothele rara. Acrothele spmri Walcott [1908d, pp. 86-87] Acrothele spurri. Acrothele subsidua Beecher [1891, PL XVII, fig. 12]. Acrothele subsidua. Grabau and Shimer [1907, p. 200] Do. Hall and Clarke [1892c, pp. 100 and 103] "Do. Matthew [1902c, p. 110] ' Do. Matthew [1903, p. 103] Acrothele spurri. Walcott [1886b, pp. 108-109, PL IX, figs. 4a-c] Acrothele subsidua. The paragraph on page 109 includes reference to this species and to Acrothele spurri. Walcott [1886b, p. 109, PL IX, fig. 4] Acrothele spurri. The paragraph on page 109 includes reference to this species and to Acrothele subsidua. Walcott [1891a, p. 608, PL LXX, fig. 1] Acrothele spurri. The text includes refer- ence to this species and to Acrothele sub- sidua. SYNONYMIC REFERENCES. 29 Present reference. Acrothele subsidua Walcott [1891a, pp. 608-609, PL LXX, figs, la-c] Acrothele subsidua. The text includes reference to this species and to Acrothele epurri. ^Vhite [1880, p. 47] Acrothele subsidua. Acrothele subsidua hera Walcott [190Sd, p. 87] Acrothele subsidua hera. Acrothele subsidua Isevis Walcott [new] Acrothele subsidua lasvis. Acrothele turneri Walcott [1908d , pp . 87-88] Acrothele turneri . Acrothele villaboimensis Delgado [1904, p. 365] Acrothele villaboimensis. Acrothele woodworthi Walcott [1908d, p. 88] Acrothele woodworthi. Acrothele yorkensis Walcott [1908d, pp. 88-89] Acrothele yorkensis. Acrothele sp. undt. Walcott [new] Acrothele sp. undt. a. Acrothele sp. Moberg [1892b, pp. 114-115] Acrothele sp. undt. b. Pompeck]" [1896b, p. 603] Botsfordia? barrandei (in part) and Acro- thele bergeroni (in part). Acrothele (Redhchella) Walcott [1908d, pp. 89-90] Acrothele (Redhchella). Walcott [1908e, PI. XI, and pp. 142 and 146] Do. Aero thyra Matthew {1901b, pp. 303-304] Acrothyra. Matthew [1902c, p. 104] Do. Matthew [1903, pp. 85-86] ' Do. Matthew [1903, pp. 88-89] Do. Walcott [1908e, PI. XI, and pp. 142 and 146] Do. Acrothyra? inflata Matthew [1901b, p. 304] Acrotreta inflata. (Acrothyra?) inflata [Lingulella], Matthew [1902b, p. 390] Do. Acrothyra minor Walcott [1905a, p. 303] Acrothyra minor. Acrothyra proavia Matthew [1902b, pp. 386-388] i Acrothyra proavia. Matthew [1903, pp. 53-55] Do. Acrothyra proavia crassa Matthew [1902b, pp. 389-390] Do. Matthew [1903, p. 94] Do. . Acrothyra proavia prima Matthew [1901b, p. 303] Do. Matthew [1902b, p. 389] Do. Matthew [1903, pp. 58, 86, and 93] Do. Acrothyra signata Matthew [1902b, pp. 381-382] Acrothyra signata. Matthew [1903, p. 87] Do. Acrothyra signata orta Matthew [1902b, pp.' 385-386] Acrothyra signata orta. Matthew [1903, pp. 89-90] Do. Acrothyra signata prima Matthew [1902b, pp. 382-383] Acrothyra signata prima. Matthew [1903, p. 73] Do. Acrothyra (signata) sera Matthew [1902b, pp. 383-384] Acrothyra sera. Acrothyra signata sera Matthew [1903, p. 56] Do. Matthew [1903, pp. 87-88] , Do. Acrothyra signata tarda Matthew [1902b, pp. 384-385] Do. Matthew [1903, p. 89] Do. Acrotreta Dall [1877, p. 12] Acrotreta. Davidson [1853, p. 133].. Do. Davidson [1871, p. 343] Do. Grabau and Shimer [1907, p. 199] Do. Hall and Clarke [1892a, p. 250] Do. Hall and Clarke [1892b, p. 566] Do. Hall and Clarke [1892c, pp. 101-104] Do. Kutorga [1848, pp. 259, 260, and 275] ; Do. Matthew [1902b, p. 390] Do. Matthew [1903, pp. 94 and 96-97] Do. Morris [1849, pp. 316 and 318] Do. Oehlert [1887, p. 1266] Do. vonSeebach [1865, p. 341] Do. Walcott [1884b, pp. 16-17].: Do. Walcott [1908e, PI. XI, and pp. 142 and 146] Do. Zittel [1880, p. 666] Do. Acrotreta argenta Walcott [1902, pp. 580-581] Acrotreta argenta. Acrotreta attenuata Meek [1873, p. 463] Acrotreta attenuata (in part), A. attenuata var. (in part), and A. idahoensis (in part). Walcott [1905a, p. 298] Acrotreta attenuata. 30 - CA]\IBRIAN BRACHIOPODA. Present reference. Acrotreta attenuata var.? Walcott [1905a, p. 29S] Acrotreta attenuata var.? Acrotreta babel Barrande [lS79b, PI. XCV, figs, vii: 1-2] Acrotreta babel. Acrotreta baileyi Hall and Clarke [1892a, PI. Ill, figs. 28-30] Acrotreta baileyi. Hall and Clarke [1892c, p. 102] Do. Matthew [1SS6, pp. 36-37] Do. Matthew [1902b, p. 395] Do. Matthew [1903, p. 97] Do. Walcott [1902, pp. 581-582] Do. Acrotreta baileyi ? Matthew [1892, p. 43] ! Acrotreta bisecta. Acrotreta bellatula Walcott [190Sd, pp. 93-94] Acrotreta bellatula. Acrotreta bisecta Matthew [1901a, pp. 275-276] Acrotreta bisecta. Matthew [1902b, p. 394] Do. Matthew [1903, pp. 186-187] Do. Walcott [1902, p. 582] , Do. Walcott [1905a, pp. 298-299] Do. Acrotreta? cancellata Walcott [1905a, p. 299] Acrotreta? ? cancellata. Acrotreta carinata Moberg and Segerberg [1906, p. 66] Acrotreta carinata. (Acrotreta?) ceratopygarum [Discina], Brogger [1882, p. 47] Acrothele ceratopygarum. Acrotreta circularis Moberg and Segerberg [1906, pp. 65-66] Acrotreta circularis. Acrotreta claytoni Walcott [1902, p. 583] Acrotreta claytoni. Acrotreta concentrica Walcott [1902, p , 583] Acrotreta concentrica. Acrotreta conula Walcott [1902, p. 584] Acrotreta conula. Acrotreta convexa Walcott [1902, p. 584] Acrotreta convexa. 1 ■ Acrotreta curvata Walcott [1902, p. 584] Acrotreta curvata. Acrotreta definita AValcott [1902, pp. 584-585] Acrotreta definita. Acrotreta depressa Walcott [1908c, p. 245] Acrotreta depressa. Acrotreta dichotoma Hall and Clarke [1892c, pp. 100 and 103] Acrothele dichotoma. Walcott [1886b, p. 107] Do. Acrotreta eggegrundensis Walcott [1905a, pp. 299-300] Acrotreta eggegrundensis. Wiman [1902, p. 55] Do. Acrotreta emnionsi Walcott [1905a, p. 300] Acrotreta emmonsi. Acrotreta gemma Billings [1865a, pp. 216-217] Acrotreta gemma. Grabau and Shinier [1907, p. 199] Acrotreta primseva. Hall and Clarke [1892c, p. 102, fig. 55] Acrotreta curvata. Hall and Clarke [1892c, p. 102, figs. 56 and 57] Acrotreta idahoensis alta. Walcott [1884b, pp. 17-18] Acrotreta attenuata (in part), A. pyxidi- cula (in part), A. curvata (in part), and A. idahoensis alta (in part). The text includes all four species, but the last two were the only ones figured. Walcott [1884b, pp. 17-18, PI. I, figa. la-b] Acrotreta idahoensis alta. Walcott [1884b, pp. 17-18, PI. I, figs. Id-e] Acrotreta curvata. Walcott [18S6b, pp. 98-99] Acrotreta attenuata (in part), A. pyxidi- cula (in part), and A. primaeva (in part). The text includes all three species, but the last was the only one figiu-ed . Walcott [1886b, pp. 98-99, PI. VIII, figs. 1, la-b] Acrotreta primseva. Walcott [1891a, p. 608] Acrotreta attenuata (in part), A. pyxidi- cula (in part), A. curvata (in part), A. idahoensis alta (in part), and A. pri- mseva (in part). The text includes all five species, but the last three were the- only ones figured. Walcott [1891a, p. 608, PL LXVII, figs. 5 and 5a] Acrotreta idahoensis alta. Walcott [1891a, p. 608, PI. LXVII, fig. 5b] Acrotreta curvata. Walcott [1891a, p. 608, PL LXVII, 5c-e] Acrotreta primseva. Walcott [1899, p. 449] ; Acrotreta attenuata (in part), A. pyxidi- cula (in part), A. curvata (in part), A. idahoensis alta (in part), and A. pri- mseva (in part). The text includes all five species, but the last three were the only ones figured. Walcott [1899, p. 449, PL LXII, figs. 2, 2b, and 2d] Acrotreta primseva. SYNONYMIC EEFEEENCES. 31 Present reference. Acrotreta gemma Walcott [1899, p. 449, PI. LXII, figs. 2a and 2c] Acrotreta idahoensis alta. Walcott [1899, p. 449, PI. LXII, fig. 2e] Acrotreta curvata. Acrotreta gemma depressa Matthew [1902c, p. 109] Acrotreta depressa. Walcott [18S9C, pp. 441-442] Do. Acrotreta gemmula Matthew [1894, pp. 87-88] Acrotreta gemmula. Matthew [1895a, p. 126] Do. Matthew [1903, p. 97] Do. Acrotreta gracia Walcott [1902, pp. 586-587] Acrotreta gracia. Acrotreta? gulielmi Matthew [1886, pp. 37-39] Discinopsis gulielmi. Acrotreta idahoensis Walcott [1902, p. 587] Acrotreta idahoensis. Acrotreta cf . idahoensis Walcott [new] ^ Acrotreta cf . idahoensis. Acrotreta idahoensis alta Walcott [1902, p. 588] Acrotreta idahoensis alta. Acrotreta idahoensis sulcata Walcott [1902, p: 588] Acrotreta idahoensis sulcata. Acrotreta inchoans Pompeckj [1896a, p. 3] Acrotreta inchoans. Acrotreta inflata Walcott [1902, pp. 588-589] Acrotreta inflata. Acrotreta kutorgai Walcott [1902, pp. 589-590] Acrotreta- kutorgai (in part) and A. rudis (in part). Acrotreta liani Walcott [1905a, p. 300] Acrotreta lisani. Acrotreta limoensis Wiman [1902, p. 54] Acrotreta uplandica limoensis. Acrotreta marjumensis Walcott [1908d, pp. 94-9.5] Acrotreta marjumensis. Acrotreta microscopica missouriensis Walcott [1902, p. 590] Acrotreta microscopica missouriensis. Acrotreta microscopica tetonensis Walcott [1902, p. 590] Acrotreta microscopica tetonensis. Acrotreta minuta Walcott [1901, p. 673] Linnarssonella minuta. Acrotreta miser Walcott [1902, pp. 590-591] Acrotreta misera. Acrotreta neboensis Walcott [1905a, pp. 300-301] Acrotreta neboensis. Acrotreta? nicholsoni Davidson [1868, pp. 313-314] Acrotreta nicholsoni. Davidson [1871, pp. 343-344] Do. Acrotreta nicholsoni Davidson [1883, p. 213]. - Do. Hall and Clarke [1892c, p. 103] Do. Swanston [1877, PI. VII, figs. 21a-c] Do. Swanston [1886, PI. VII, figs. 21a-c] Do. Acrotreta sp. cf . nicholsoni Matley [1902, p. 142] Acrotreta sabrinse. Acrotreta nox Walcott [1905a, p. 301] Acrotreta nox. Acrotreta celandica Westergard [1909, p. 76] Acrotreta oelandica. Acrotreta ophirensis Walcott [1902, pp. 591-592] Acrotreta ophirensis. Acrotreta cf. ophirensis Walcott [new] Acrotreta cf . ophirensis. Acrotreta ophirensis descendens Walcott [1908d, p. 95] Acrotreta ophirensis descendena. Acrotreta ophirensis rugosus Walcott [1902, p. 592] Acrotreta ophirensis rugosa. Acrotreta ovalis Walcott [1902, p. 592] Acrotreta ovalis. Acrotreta pacifica Walcott [1905a, p. 301] Acrotreta pacifica. Acrotreta papellata-prima Matthew [1902b, pp. 391-392] Acrothyra sera. Acrotreta papillata Matthew [1902b, pp. 390-391] Do. Matthew [1903, p. 95] Do. Acrotreta papillata lata Matthew [1903, pp. 9-5-96] Do. Acrotreta papillata-prima Matthew [1903, pp. 73-74] Do. Acrotreta papillata var. Matthew [1902b, p. 391] Do. Acrotreta parvula Walcott [1902, p . 592] Acrotreta parvula. Acrotreta primaaea Walcott [1902, p. 593] Acrotreta primaeva. Acrotreta proavia Matthew [1899b, p. 203] Acrothyra proavia. Acrotreta pyxidicula ^Tiite [1874, p. 9] '. Acrotreta pyxidicula. White [1877, pp. 53-54] Do. Acrotreta recurva Kutorga [1848, pp. 277-278] Volborthia recurva. Acrotreta rudis Walcott [1908d, pp. 9.5-96] ..Acrotreta rudis. Acrotreta (?) sabrinse Matley [1902, p. 143] Acrotreta sabrinse. Acrotreta (?) sabrinse malvernensis Matley [1902, pp. 143-144] Do. (Acrotreta?) sagittalis [Obolella], Moberg and Segerberg [1906, p. 64] Acrotreta sagittalia. Acrotreta cf. sagittalis Walcott [new] Acrotreta cf. sagittalis. Acrotreta sagittalis magna Walcott [1902, pp. 595-596] Acrotreta sagittalis magna. Acrotreta sagittalis taconica Walcott [1902, pp. 596-597] Acrotreta sagittalis taconica. Acrotreta schmalenseei Walcott [1902, pp. 597-598] Acrotreta schmalenseei. Acrotreta seebachi Moberg and Segerberg [1906, pp. 66-67] Acrotreta seebachi . Walcott [1902, pp. 598-599] Do. Acrotreta shantungensis W^ilcott [1905a, pp . 301-302] Acrotreta shantungensis. Acrotreta signalis Walcott [1902, p. 599] Acrotreta signalis. 32 CAMBRIAN BRACHIOPODA. ' • Present reference. Acrotreta sipo Matthew [1902b, pp. 406-407] .' Acrotreta bisecta. Matthew [1903, pp. 1S5-18G] Do. Acrotreta socialis Gronwall [1902, p. 39] Either Acrotreta schmalenseei or A. socialis. (See p, 712.) Linnarsson [1876, pp. 16-18] Acrotreta schmalenseei. Linnai'ssoD [1877, p. 374] Either Acrotreta schmalenseei or A. soci- alis. (See p. 712.) von Seebach [1865, p. 341] Acrotreta socialis. Walcott [1902, pp. 599-600] Do. Wallerius [1895, p. 66] Acrotreta schmalenseei. Acrotreta of. socialis Brogger [1882, pp. 46^7, PL X, figs. 2, 2a-b] Acrotreta carinata. Brogger [1882, pp. 46-47, PI. X, figs. 3 and 4] Not referred in this monograph. Matley [1902, pp. 144-145] Acrotreta sabrinse. Matthew [1902b, pp. 392-394] Acrotreta sp. undt. Matthew [1903, pp. 183-185] Do. Acrotreta spinosa Walcott [1905a, p. 302] Acrotreta spinosa. Acrotreta subconica Daiddson [1853, PI. IX, figs. 271-275] Acrotreta subconica. Kutorga [1848, p. 275] Do. Meek [1873, p. 463] Acrotreta attenuata (in part), A. attenuata var. (in part), and A. idahoensis (in part). Quenstedt [1885, p. 755] 1 Acrotreta subconica. von Seebach [1865, p. 341] ; Do. Walcott [1902, pp. 600-601]..... Do. , Acrotreta? subsidua White [1874, p. 6] Acrothele subsidua. ■White [1877, pp. 34-36] Do. Acrotreta ulrichi Walcott [190Sd, pp. 96-97]. . : Acrotreta ulrichi. "- Acrotreta uplandensis Walcott [1905a, p. 302] Acrotreta uplandica. Acrotreta uplandica Wiman [1902, p. 54] Do. A-crotreta uplandica limonensis Walcott [1905a, p. 303] Acrotreta uplandica" limoensis. Acrotreta sp. Morris [1849, PI. VII, figs. 4a-b] Acrotreta subconica. Westerg^rd [1909, pp. 57 and 77] : Acrotreta sp. undt. Acrotreta ( Volborthia) Oehlert [1887, p. 1266] Volborthia. acuminata [Glossina], Hall and Clarke [1892a, PI. I, figs, 10 and 11] Lingulella (Lingiilepis) acuminata sequens. acuminata [Lingula], Billings [1863, p. 102] Lingulella (Lingulepis) acuminata. Chapman [1863, p. 187] Do. Chapman [1864, p. 159] ^. Do. Conrad [1839, p. 64] Do. Emmons [1855, p. 203] Do. Hall [1847, p. 9] Do. acuminata [Lingula (Glossina)], Hall and Clarke [1892c, PI. I, figs.l and 2].. Lingulella (Lingulepis) acuminata sequens. acuminata [Lingulepis], Dwight [1886, p. 208] Lingulella (Lingulepis) acuminata. Matthew [lS95b, pp. 257-258] Do. Schuchert [1897, p. 2.59] Do. Walcott [1897a, p. 404] Do. acuminata meeki [Lingulepis], Delgado [1904, pp. 366-367] Lingulella delgadoi. acuminata sequens [Lingulella (Lingulepis)], Walcott [1908d, p. 72] Lingulella (Lingulepis) acuminata sequens. acuminatus [Obolus (Lingulepis)], Walcott [189.9, p. 443] Lingulella (Lingulepis) acuminata. acuminatus [Obolus (Schmidtia)], Mickwitz [1896, pp. 179-183] Obolus (Schmidtia) acuminatus. acuminatus alatus [Obolus (Schmidtia)], Mickwitz [1896, pp. 183-184] Do. acuminatus humeratus [Obolus (Schmidtia)], Mickwitz [1896, pp. 184-186]. Do. acuminatus meeki [Obolus (Lingulepis)], Walcott [1899, p. 444] Lingulella (Lingulepis) acuminata meeki. acuminatus subtriangularis [Obolus (Schmidtia)], Mickwitz [1896, pp. 186-187] Obolus (Schmidtia) acuminatus. acutangula [Lingula], Roemer [1849, p. 420] Lingulella acutangula. Roemer [18.52, p. 90] Do. acutangulus [Lingulepis], Schuchert [1897, p. 259] Do. acutangulus [Obolus (Lingulella)], Walcott [1898b, pp. 393 and 394, Pis, XXVII and XXVIII] Do. acutus [Obolus (Schmidtia) obtusus], Mickwitz [1896, pp. 172-173] Obolus (Schmidtia) obtusus. . advena [Obolus?], Barrande [1879b, PI. XCV, fig. iv] Obolus? advenua. aquiputeis [Obolus], Matthew [1902c, p. 94] Obolus selwyni. Matthew [1903, p. 139] Do. affinis [Lingulella?], Billings [1872b, p. 468] Obolus (Lingulobolus) affinis. Billings [1874, p. 67] Do. affinis [Lingulella], Billings [1882, pp. 1.5-16] Do. SYNONYMIC REFERENCES. 33 Present reference. affinis [Lingulepis], Walcott [1889a, p. 381] Obolua (Lingulobolus) affinis. affinis [Lingulobolus], Grabau [1900, pp. 621-622] Do. Matthew [189.5b, pp. 261-262] Do. affinis [Obolus (Lingulobolus)], Walcott [1898a, p. 327] Do. affinis cuneata [Lingulobolus], Matthew [1895b, p. 262] Do. agnostorum [Lingula], Wallerius [1895, pp. 64-65] : Lingulella agnostorum. agreste [Orthis (Plectorthis)], Walcott, [1906, p. 570] Eoorthis agreate. alabamaensis [Iphidea], Walcott [1897b, pp. 713-714] Micromitra alabamaensis. alandensis [Obolus (Westonia)], Walcott [1905a, p. 334] Obolus (Westonia) alandensis. alata? [Kutorgina], Moberg [1892b, p. 113] Belongs with an undetermined -genua. alata [Syntrophia], Walcott [190.3a, p. 290] Syntrophia alata. alatus [Obolus (Schmidtia) acuminatus], Mickwitz [1896, pp. 183-184] Obolus (Schmidtia) acuminatus. alberta [Billingsella], Schuehert [1897, p. 158] Nisusia alberta. alberta [Nisusia], Walcott [1905a, pp. 248-249] • Do. Walcott [1908c, p. 245] Do. alberta [Orthisina], Matthew [19020, p. 109] Do. Walcott [1889c, p. 442] Do. alta [Acrotreta idahoensis], Walcott [1902, p. 588] Acrotreta idahoensia alta. ambigua [Billingsia?], Ford [1886a, p. 467] Elkania ambigua. ambigua [Elkania], Ford [1886b, p. 325] Do. Hall and Clarke [1892c, p. 78] Do. ambigua [Obolella?], Walcott [1884b, pp. 67-68] Do. amii [Nisusia (Jamesella)], Walcott [1905a, p. 252] Nisusia (Jameaella) amii. ampla [Lingula], Hall [1863, p. 125] Lingulella ampla. Hall [1867, pp. 101-102] Do. Owen [1852. p. 583] Do. ampla [Lingulella], Schuehert [1897, p. 257] Do. amplus [Obolus (Lingulella)], Walcott [1898b, pp. 392 and394, PL XXVIII]. Do. anceps [Obolus], Walcott [1898b, pp. 388-389] Obolus anceps. ancilla [Lingula], Barrande [1879b, PI. CXI, fig. vi] Obolus ? ancillus. angulatus [Obolus (Schmidtia) craesus], Mickwitz [1896, pp. 193-194] Obolus (Schmidtia) crassus. anomala [Billingsella?], Walcott [1905a, p. 230] Wimanella ? anomala. Anomites lenticularis Wahlenberg [1821, pp. 66-67] Orusia lenticularis. antiqua [Lingula], Billings [1856, p. 34] Lingulella (Lingulepis) acuminata. Emmons [1842, p. 268] Do. Emmons [1863, p. 92] Do. Hall [1847, pp. 3-4] Do. Hall [1851, pp. 204-205] Do. Hall [1862, fig. 2, p. 21] Do. Hayden [1862, p. 73] Do. James [1895, p. 884] ;.. Do. Owen [1851, p. 170] Do. Rogers [1861, p. 390] Obolus (Westonia) rogersi. antiquata [Camarella?], Hall and Clarke [1893b, pp. 220-221] Swantonia antiquata. antiquata [Camarella], Walcott [1886b, pp. 122-123] Do. Walcott [1891a, p. 613] Do. antiquata [Camerella], Billings [1861b, pp. 10-11] Do. Billings [1861c, p. 949] Do. Billings [1862e, p. 221] Do. Billings [1863, fig. 290, p. 284] Do. antiquata [Lingula], Emmons [1855, pp. 202-203] Lingulella (Lingulepis) acuminata. antiquata [Protorhyncha?], Schuehert [1897, p. 334] Swantonia antiquata. antiquata [Swantonia], Walcott [1905a, pp. 296-297] Do. antiquissima [Acritis], Gagel [1890, p. 22] Obolus (Acritis) antiquissimus. Hall and Clarke [1892c, p. 82] Do. Volborth [1869, pp. 212-217] . Do. antiquissima [Aulonotreta], Hall and Clarke [1892a, figs. 246 and 247, p. 244] Do. Hall and Clarke [1892b, figs. 246 and 247, p. 560]. Do. antiqulssimus [Obolua], Eichwald [1859, PI. XXXVII, figs. 5a-d] Do. Eichwald [1860, pp. 928-929] Do. antiquissimua [Obolus (Acritia)], Mickwitz [1896, pp. 206-213] Do. antiquiaaimua [Obolus (Lucina)], Eichwald [1843b, pp. 142-144] Do. antiquiaaimus ventrosua [Obolus (Acritis)], Mickwitz [1896, pp. 213-214]... Do. 62667°— VOL 51, pt 1—12 3 34 CMIBRIAN BKACHIOPODA. Present reference. apoUinis [Obolus], Billings [1872a, p. 218] Obolus apoUiuis. Billings [1872c, p. 356] Do. Davidson [18-53, figs. 51 and 52, p. 136, and PI. IX, figs. 280-284] Do. Davidson [1853, PI. IX, fig. 285] Obolus (Acritis) antiquissimus. Eichwald [1829, p. 274] Obolus apollinis. Eichwald [1840, p. 167] Do. Eichwald [1843b, p. 140] Do. Eichwald [I860, pp. 925-926] Do. Gagel [1890, pp. 21-22] Do. Hall and Clarke [1892a, figs. 247 and 248, p. 242] Do. Hall and Clarke [1892b, figs. 247 and 248, p. 558] Do. Hall and Clarke [1892c, p. 80] Do. Kutorga [1848, pp. 251 and 252] Do. Matthew [1892, pp. 43^4] Do. Mickwitz [1896, pp. 133-137] Do. Moberg and Segerberg [1906, p. 6.5] Do. Morris [1849, p. 316] Do. Noetling [1883, p. 265] Do. Roemer [1876, PL II, figs. 7a-c] Do. Roemer [1885, pp. 23-24 (270-271)] Do. Schmidt [1861, p. 218] Do. de Verneuil [1845, pp. 290-292] Obolus apollinis (in part), 0. apollinis ingricua (in part), Obolus (Acritis) anti- quissimus (in part), and Obolus (Mick- witzella) siluricus (in part). Walcott [1898b, PL XXVI, figs. 3-6] Obolus apollinis. Westergard [1909, p. 56] Do. Zittel [1880, figs. 488a-c, p. 664] ---- Do. Zittel [1880, fig. 488d, p. 664] Obolus apollinis quenstedti. apollinis [Ungulites], Quenstedt [1885, pp. 755 and 756] Obolus apollinis. apollinis ingricus [Obolus], Mickwitz [1896, pp. 137-140] Obolus apollinis ingricus. apollinis maximus [Obolus], Mickwitz [1896, pp. 140-143] Obolus apollinis maximus. apollinis quenstedti [Obolus], Mickwitz [1896, pp. 143-145] Obolus apollinis quenstedti. appalachia [Billingsella?], Walcott [1905a, p. 231] Billingsella? appalachia. appalachia [Dicellomus], Walcott [1905a, p. 314] Dicellomus appalachia. appolinus? [Obolus], Owen [1852, p. 501] Dicellomus politus. argenta [Acrotreta], Walcott [1902, pp. 580-581] Acrotreta argenta. argenta [Nisusia (Jamesella)], Walcott [1905a, p. 252] Nisusia (Jamesella) argenta. argia [Syntrophia primordialis], Walcott [1905a, p. 293] Syntrophia primordialis argia. argutus [Obolus (Lingulella)], Walcott [1898b, p. 396] Lingulella arguta. artemis [Acrothele], Walcott [1908d, p. 82] Acrothele artemis. asiatica [Obolella], Walcott [1905a, p. 297] Obolella asiatica. aspera [Lingulella radula], Matthew [1903, pp. 204-205] Lingulella radula. atava [Orthis (Plectorthis?)], Walcott [1905a, pp. 259-260] Eoorthis atava. atava [Rafinesquina?], Schuchert [1897, p. 338] Do. atava [Strophomena], Matthew [1893b, pp. 102-103] Do. atava [Strophomena?], Moberg and Segerberg [1906, PL II, figs. 7, 7a-b] . . Do. atavus [Leptobolus], Matthew [1899b, pp. 200-201] Lingulella atava. Matthew [1903, pp. 106-109] Do. atavus [Obolus (Lingulella)], Walcott [1902, pp. 609-610] Do. atavus insula [Leptobolus], Matthew [1903, pp. 110-112] Lingulella atava insute. . atavus tritavus [Leptobolus], Matthew [1903, p. 109] Lingulella torrentis. atlantica [Obolella], Burr [1900, p. 47] Obolella atlantica. Gorham [1905, PI. I, figs. 2a-c] Do. Grabau [1900, pp. 620-621] Do. Grabau and Shimer [1907, p. 188] Do. Matthew [1899d, p. 70] Do. Walcott [1890b, p. 36] Do. Walcott [1891a, p. 611] Do. atlantica [Obolella cf.], Delgado [1904, p. 364] Obolella? sp. undt. a. Atrypa? lenticularis Dalman [1828, pp. 132-133] Orusia lenticularis. Hisinger [1837, p. 76] Do. SYNONYMIC REFERENCES. 35 Present reference. Atrypa lenticularis Kjerulf [1857, p. 92] Orusia lenticularis. Kjerulf [1865, pp. 1 and 3] J Do. Kjerulf [1879, PL XIII] Do. atrypoides [Orthia lenticularis], Matthew [1892, p. 48] Orusia lenticularis atrypoides. Matthew [1903, p. 217] Do. atrypoides [Orthis (Orusia) lenticularis], Walcott [1905a, p. 276] Do. attenuata [Acrotreta], Meek [1873, p. 463] .•• Acrotreta attenuata (in part), A. attenuata var. (in part), and A. idahoensis (in part). Walcott [1905a, p. 298] Acrotreta attenuata. attenuata [Lingula], Bornemann [1891, pp. 437-438] Lingulella bornemanni. attenuata var. [Acrotreta], Walcott [ISOoa, p. 298] Acrotreta attenuata var.? auga [Obolus (Lingulella)], Walcott [1898b, pp . 396-397] Lingulella auga. Aulonotreta Dall [1877, p. 16] Obolus (Acritis) . Hall and Clarke [1892a, pp. 243-244] Obolus (in part) and 0. (Acritis) (in part). Hall and Clarke [1892b, pp. 559-560] Do. Hall and Clarke [1892c, p. 82].. Do. Kutorga [1848, pp. 278-279] Obolus (in part), 0. (Acritis) (in part), and O. (Mickwitzella) (in part). Morris [1849, pp. 316-317] Obolus (Acritis). Aulonotreta antiquissima Hall and Clarke [1892a, figs. 246 and 247, p. 244].. Obolus (Acritis) antiquissimus. Hall and Clarke [1892b, figs. 246 and 247, p. 560]. . Do. Aulonotreta polita Kutorga [1848, pp. 279-282] Obolus apollinis (in part), 0. apollinis ingricus (in part), and O. (Mickwitzella) eiluricus (in part). Aulonotreta sculpta Dall [1877, p. 16] Obolus (Acritis) antiquissimus. Kutorga [1848, pp. 282-283] Do. aurora [Lingula], Hall [1861, p. 24] Obolus (Westonia) aurora. Hall [1862, p. 21] Do. Hall [1863, pp. 126-127] Do. Hall [1867, pp. 103-104] Do. Sardeson [1896, p. 95] Do. aurora [Lingulella], Grabau and Shimer [1907, p. 193] Do. Hall [1873, pp. 244-245] Do. Hall and Clarke [1892c, PI. II, figs. 12 and 13] Do. aurora [Obolus (Westonia)], Walcott [1901, p. 691] Do. aurora var. [Lingula], Hall [1863, pp. 127-128] Obolus (Westonia) stoneanus. Hall [1867, pp. 104-106] Do. aurora var. [Lingulella], Hall [1873, pp. 244-245] Do. avia [Acrothele], Matthew [1899b, pp. 202-203] Acrothele avia. Matthew [1902b, pp. 396-398] Do. Matthew [1903, pp. 55 and 98-99] Do. avia-puteis [Acrothele], Matthew [1902b, p. 398] Acrothele avia puteis. Matthew [1903, p. 100] Do. Avicula? desquamata Hall [1847, p. 292] Obolella crassa. B. babel [Acrotreta], Barrande [1879b, PI. XCV, figs, vii: 1-2] Acrotreta babel. baileyi [Acrotreta], Hall and Clarke [1892a, PI. Ill, figs. 28-80] Acrotreta baileyi. Hall and Clarke [1892c, p. 102] Do. Matthew [1886, pp. 36-37] Do. Matthew [1902b, p. 395] Do. Matthew [1903, p. 97] Do. Walcott [1902, pp. 581-582] Do. baileyi? [Acrotreta], Matthew [1892, p. 43] Acrotreta bisecta. baltica [Obolus (Westonia)], Walcott [1905a, p. 334] Obolus (Westonia) balticus. barabuensis [Lepteena], WTaitfield [1878, p. 60] Syntrophia barabuensis. Whitfield [1882, pp. 171-172 and 195] Do. barabuensis [Orthis], A. Winchell [1864, p. 228] Do. barabuensis [Syntrophia], Hall and Clarke [1893b, p. 216] Do. Walcott [1905a, pp. 290-291] Do. barbata [Acrothele], Moberg and Segerberg [1906, pp. 67-68] Acrothele ceratopyganim. barrandei [Botsfordia?], Walcott [1908d, pp. 77-78] Botsfordia? barrandei. 36 CAMBRIAN BRACHIOPODA. Present reference. bavarica [Lingula], Barrande [1868a, p. 100] Obolus? bavaricus. Barrande [1868b, pp. 690-6911 Do. bavarica [Orthis], Barrande [1868a, p. 99] Eoorthis bavarica. Barrande [1868b, p. 690] Do. bella [Iphidea], Billings [1872b, pp. 477-478] Micromitra (Paterina) bella. Billings [1874, p. 76] Do. Billings [1882, p. 13] Do. Clark and Mathews [1906, p. 252] Do. Gi-abau and Shimer [1907, p. 201] Do. Hall and Clarke [1892a, p. 249] Micromitra (Paterina) labradorica swanton- ensis. Hall and Clarke [1892c, p. 98, fig. 54] Micromitra (Paterina) bella. The text in- cludes both M. (P.) bella and M. (P.) labradorica swantonensis. Hall and Clarke [1892c, p. 98, PI. IV, figs. 8 and 9] Micromitra (Paterina) labradorica swanton- ensis. The text includes both M. (P.) labradorica swantonensis and M. (P.) bella. Oehlert [1887, p. 1270] Micromitra (Paterina) bella. Walcott [1886b, p. 100] Do. Walcott [1891a, p. 608] Do. beUa? [Iphidea], Grabau [1900, pp. 617-618] Do. bellapunctata [Acrothele], Walcott [1908d, pp. 82-83] Acrothele bellapunctata. ' bellatula [Acrotreta], Walcott [1908d, pp. 93-94] Acrotreta bellatula. belli [Lingida], Billings [1859, pp. 431^32] Obolus belli. Billings [1863, figs. 47a-b, p. 124] Do. bellula [Acrothele], Walcott [1897b, pp. 716-717] Acrothele beUuIa. bellula [Elkania], Walcott [1905a, p. 323] Obolus (FordLnia) beUuIus. bellulus [Obolus (Lingulella)], Matthew [1903, p. 205] LinguleUa bellula. Walcott [1898b, p. 398] Do. beUus [Obolus (LinguleUa)], Matthew [1903, p. 204] Lingulella bella. Walcott [1898b, pp. 397-398] Do. I Walcott [1901, pp. 685-687] Lingulella beUa (in part), L. concinna (in part), and L. lens (in part). belti [Linnarssonia], Matley [1902, p. 145] Acrotreta belti. belti? [Linnarssonia], Matthew [1892, pp. 42-43] (?) This species is not specificaUy referred in this monograph; it does not belong with Acrotreta belti. belti [Linnarssonia cf.], Matthew [1903, pp. 209-210] Do. belti [Obolella], Davidson [1868, pp. 310-311] Acrotreta belti.' Davidson [1871, pp. 340-341] Do. belti [Obolella sagittalis], Davidson [1871, desc. of PL L, figs. 15-17] Do. belti magna [Linnarssonia], Matthew [1897b, pp. 169-170] Acrotreta sagittalis magna. bergeroni [Acrothele], Walcott [1908d, pp. 83-84] Acrothele bergeroni. bicens's [Obolus (Lingulella)], Walcott [1901, p. 688] Botsfordia caslata. Bicia Walcott [1901, pp. 676-678] Bicia. Walcott [1908e, PI. XI, and pp. 142 and 144] Do. Bicia gemma Walcott [1901, pp. 678-680] Bicia gemma. Bicia whiteavesi Walcott [1901, p. 680] Bicia whiteavesi. billingsana [Lingula], Matthew [1903, p. 205] Lingulella bellula. billingsana [LinguleUa?], Schuchert [1897, p. 256] Lingulella grandis (in part) and L. billings- iana (in part). BlUingsella Grabau and Shimer [1907, p. 210] BiUingsella. HaUand Clarke [lS92a, p. 273] Do. HaU and Clarke [1892b, p. 589] Do. Hall and Clarke [1892c. pp. 230-231] BiUingsella (in part) and Nisusia (in part). Schuchert [1897. p. 158] BUlingsella (in part), Protorthis (in part), and Nisusia (in part). Walcott [1905a, pp. 227-229] BiUingsella (in part) and WimaneUa (in 1 part). Walcott []908e, PI. XI, and pp. 142 and 148] BiUing.sella. BiUingsella alberta Schuchert [1897, p. 158] Nisusia alberta. BillingseUa? anomala Walcott [1905a. p. 230] WimaneUa ? anomala. SYNONYMIC REFERENCES. " 37 Present reference. Billingsella? appalachia Walcott [1905a, p. 231] Billingsella? appalachia. Billingsella billingsi Schuchert [1897, p. 158] Protorthis billingsi. (Billingsella) billingsi [Protorthis], Grabau and Shimer [1907, p. 211] Do. Billingsella bivia Walcott [new] Billingsella bivia. Billingsella circe Walcott [1901, p. 673] Quebecia circe. Billingsella coloradoensis Grabau and Shimer [1907, p. 210] Billingsella coloradoensis. Schuchert [1897, p. 158] Do. Walcott [1899, pp. 450-451] Do. Walcott [1905a, pp. 231-234] Do. Billingsella dice Walcott [1905a, p. 234] BilUngsella dice. Billingsella exporrecta Walcott [1905a, pp. 234-236] Billingsella exporrecta. Billingsella exporrecta rugosicostata Walcott [1905a, p. 236] Billingsella exporrecta rugosicostata. Billingsella festinata Hall and Clarke [lS92c, p. 230] Nisusia festinata. Billingsella harlanensis Walcott [1905a, p. 236] Wimanella harlanensis. Billingsella hicksi Walcott [1905a, p. 237] Billingsella hicksi. Billingsella highlandensis Walcott [1905a, pp. 237-238] Billingsella highlandensis. Billingsella lindstromi Walcott [1905a, pp. 238-239] Billingsella lindstromi. Billingsella major Walcott [1905a, p. 239] Billingsella major. Walcott [1908d, p. 101] Do. Billingsella marion Walcott [1908d, p. 102] Billingsella marion. Billingsella obscura Walcott [1905a, p. 239] Billingsella obscura. Billingsella orientalis Hall and Clai'ke [1892c , p . 230] Billingsella orien talis . Walcott [1905a, pp. 239-240] Do. Billingsella pepina Hall and Clarke [1892a, PL VlII, figs. 1 and 2] Billingsella coloradoensis. Hall and Clarke [1892c, p. 230] Do. (Billingsella) pepina [Orthis], Sardeson [1896, p. 96] Do. Billingsella plicatella Walcott [1905a, pp. 240-241] ' Billingsella plicatella. Billingsella pumpellyi Walcott [1905a, p. 242] Billingsella pumpellyi. Billingsella quacoensis Schuchert [1897, p. 159] Protorthis quacoensis. Billingsella retroflexa Matthew [1903, pp. 148-151] Billingsella retroflexa. Billingsella richthofeni Walcott [1905a, pp. 242-243] Billingsella richthofeni. Billingsella romingeri Walcott [1905a, pp . 243-244] Billingsella romingeri . Billingsella saffordi Walcott [1905a, p. 244] Wimanella saffordi. Billingsella salemensis Walcott [1905a, p. 245] Billingsella salemensia. Billingsella striata Walcott [1905a, p. 245] Billingsella striata. Billingsella whitfieldi Schuchert [1897, p. 159] Billingsella whitfieldi. Walcott [1905a, p. 246] Do. Billingsella (Otusia) Walcott [1905a, p. 246] Otusia. Billingsella (Otusia) sandbergi Walcott [1905a, pp. 246-247] Otusia sandbergi. billingsi [Billingsella], Schuchert [1897, p. 158] Protorthis billingsi. billingsi [Orthis], Hartt [1868, pp. 644-645] Do. Hartt [1878, pp. 644-645] Do. Hartt [1891, pp. 644-645] Do. Matthew [1886, p. 43] Do. Walcott [1884a, pp. 17-18] Do. bilHngsi [Orthis (Protorthis)], Wysog6rski [1900, p. 227] Do. billingsi [Orthisina?], Matthew [1891, p. 131] Do. billingsi [Protorthis], Hall and Clarke [1892a, p. 274] Do. Hall and Clarke [1892c, pp. 219 and 232] Do. Walcott [1905a, pp. 281-282] Do. billingsi [Protorthis (Billingsella)], Grabau and Shimer [1907, p. 211] Do. billingsi [Syntrophia], Walcott [1905a, pp. 291-292] Huenella billingsi. Billingsia Ford [1886a, pp. 466-467] Elkania. de Koninck [1876] Does not equal Elkania. Walcott [1886, pp. 5, 21, 60, and 62] A genus of the Gastropoda. Billingsia? ambigua Ford [1886a, p. 467] Elkania ambigua. Billingsia desiderata Ford [1886a, pp. 466 and 467] Elkania desiderata. Billingsia? ida Ford [1886a, p. 467] Elkania ida. Billingsia pretiosa Ford [1886a, p. 467] Acrothele pretiosa. billingsiana [Lingula], ^Tiiteaves [1878, p. 226] Lingulella bilUngsiana. billingsiana [Lingula cf.], Matthew [1894, p. 93] Lingulella grandis. bisecta [Acrotreta], Matthew [1901a, pp. 275-276] Acrotreta bisecta. Matthew [1902b, p. 394] Do. Matthew [1903, pp. 186-187] Do. 38 CAilBRIAN BRACHIOPODA. Present reference. bisecta [Acrotreta], Walcott [1902, p . 582] Acrotreta bisecta. Walcott [1905a, pp. 298-299] Do. bivia [Billingsella], Walcott [new] Billingsella bivia. blackwelderi [Obelus (Westonia)], Walcott [1905a, p. 335] Obolus (Westonia) blackwelderi. bohemica [Acrothele], Hall and Clarke [lS92c, p. 101] Acrothele bohemica. Pompeckj [1896b, pp. 509-511] Do. Walcott [ISSCb, p. 107] Do. bohemicus [Obelus?], Barrande [1879b, PL CII, figs, vii: 1-3] Do. borgholmensis [Acrothele], Walcott [1908d, pp. 84-85] Acrothele borgholmensis. bornemanni [Obolus (Lingulella)], Walcott [1901, pp. 687-688] Lingulella bornemanni. Botsfordia Walcott [1908e, PI. XI, and pp. 142 and 145] Botsfordia. (Botsfordia) [Obolus], Matthew [1891, p. 148] Do. Matthew [1892, p. 63] Do. Botsfordia? barrandei Walcott [1908d, pp. 77-78] Botsfordia? barrandei. (Botsfordia) pulcher [Obolus], Matthew [1891, p. 148] Botsfordia pulchra. Matthew [1892, pp. 62-63] Do. Matthew [1902c, p. 95] Do. (Botsfordia) pulchra [Obolus], Matthew [1894, pp. 90-91] Do. Matthew [1895a, pp. 115-121] Do. bottnica [Lingula], Wiman [1902, p. 51] Obolus (Westonia) bottnicus. bottnica [Obolus (Westonia)], Walcott [1905a, pp. 335-336] Do. Brachiopode nouv. gen. de Verneuil and Barrande [1860, pp. 536-537] Botsfordia? barrandei. bretonensis [Obolus], Matthew [1902c, p. 95] Obolus (Palaeobolus) bretonensisj bretonensis [Palseobolus], Matthew [1899c, p. 202] Do. Matthew [1903, pp. 141-143]., Do. broadheadi [Linnarssonella], Walcott [1902, p. 601] Linnarssonella girtyi. (Broggeria) [Obolus], Walcott [1902, p. 605] Obolus (Broggeria). Walcott [1908e, PL XI, and pp. 142 and 144] Do. (Broggeria) salteri [Obolus], Moberg and Segerberg [1906, p. 64] Obolus (Broggeria) salteri. ■ Walcott [1902, pp. 605-606] Do. (Broggeria) salteri var.? [Obolus], Westerg&rd [1909, p. 56] Do. bryograptorum [Lingula?], Moberg and Segerberg [1906, p. 63] Lingulella lepis. Westergard [1909, p. 57] Do. buchi [Keyserlingia], Hall and Clarke [1892c, p . 118] Keyserlingia buchi. Pander [1861, columns 46^8] Do. buchi [Orbicella], Hall and Clarke [1892a, p. 254] Do. d'Orbigny [1850, p. 20] Keyserlingia buchi (in part). buchi [Orbicula], de Verneuil [1845, pp. 288-289] Keyserlingia buchi. buchii [Discina], Eichwald [1860, p. 914] Helmersenia ladogensis (in part) and Key- serlingia buchi (ia part). buttsi [Lingulella], Walcott [1908d, pp. 70-71] Lingulella buttsi. C. cselata [Lingulella], Ford [1878, pp. 127-128] Botsfordia ceelata. Hall and Clarke [1892a, PI. Ill, figs. 1-4] Do. Hall and Clarke [1892c, pp. 57 and 58] Do. Walcott [1886b, p. 95] Do. Walcott [1887, p. 199, PL I, fig. 16] Do. Walcott [1891a, p. 607] Do. cselata [Obolella], Billings [1872a, p. 218] Do. CEelata [Obolella (Orbicula)], Ford [1871, p. 33] Do. cselata [Orbicula], Hall [1847, p. 290] Do. calceoloides [Obolella wirrialpensis], Etheridge [1905, p. 249] Obolella wirrialpensis. calcifera [Camarella], Billings [1863, figs. 247a-c, p. 231] Syntrophia calcifera. calcifera [Camerella], Billings [1861a, pp. 318-320] Do. Billings [1865a, p. 220] Do. Meek [1873, p. 464] Huenella abnormis. calcifera [Syntrophia], Grabau and Shimer [1907, p. 271] Syntrophia nundina. calcifera [Syntrophia?], Hall and Clarke [1893b, p. 218] Syntrophia calcifera. calcifera [Triplecia?], Hall and Clarke [1892c, p. 270] Do. calcifera [Triplesia], Walcott [1884b, pp. 75-76] Syntrophia nundina. Camarella? antiquata Hall and Clarke [1893b, pp. 220-221] Swantonia antiquata. Camarella antiquata Walcott [1886b, pp. 122-123] Do. Walcott [1891a, p. 613] Do. SYNONYMIC REFERENCES. 39 Present reference. Camarella calcifera Billings [1863, figs. 247a-c, p. 231] Syntrophia calcifera. Camarella minor Hall and Clarke [1893b, p. 221] Obolella minor. Camarella? minor Walcott [lS91a, p. 614] Do. Cambria [Scliuchertiaa], Walcott [1905a, pp. 323-324] Schuchertina cambria. Cambria [Syntrophia], Walcott [1908d, pp. 106-107] Syntrophia cambria. Camerella antiquata Billings [1861b, pp. 10-11] Swantonia antiquata. Billings [1861c, p. 949] Do. Billings [1862e, p'. 221] Do. Billings [1863, fig. 290, p. 284] Do. Camerella calcifera Billings [1861a, pp. 318-320] Syntrophia calcifera. Billings [1865a, p. 220] Do. Meek [1873, p. 464] Huenella abnormis. Camerella minor Walcott [1890b, pp. 36-37] Obolella minor. Camerella sp.? Shumard [1861, p. 221] Huenella texana. campbelli [Syntrophia], Walcott [1908d, pp. 107-108] Syntrophia campbelli. cancellata [Acrotreta?], Walcott [1905a, p. 299] Acrotreta?? cancellata. canius [Obolue (Lingulella)], Walcott [1902, pp. 610-611] Lingulella cania. carinata [Acrotreta], Moberg and Segerberg [1906, p. 66] Acrotreta car'inata. Causea Wiman [1902, pp. 53-54] Mickwitzia. Causea formosa Wiman [1902, pp. 53-54] Mickwitzia formosa. cedens [Lingula], Barrande [1868a, p. 102] Lingulella cedens. Barrande [1868b, pp. 691-692] Do. celata [Schmidtia], Hall and Clarke [1892a, p. 244] Obolus (Schmidtia) celatus. Hall and Clarke [1892b, p. 560] Do. Hall and Clarke [1892c, p. 83] Do. Volborth [1869, pp. 209-212] Do. celatus [Obolus (Lingulella)], Walcott [1898b, PL XXVI, figs. 1 and 2] Do. celatus [Obolus (Schmidtia)], Mickwitz [1896, pp. 159-163] , Do celatus orbiculatus [Obolus], Moberg and Segerberg [1906, p. 65] Do Westergard [1909, p. 56] Do. Wiman [1902, p. 62] Do. celatus orbiculatus [Obolus (Schmidtia)], Mickwitz [1896, pp. 16.3-165] Do. celatus prsecisus [Obolus (Schmidtia)], Mickwitz [1896, pp. 166-167] Do. ceratopygarum [Acrothele], Moberg and Segerberg [1906, p. 67] Acrothele ceratopygarum. ceratopygarum [Discina (Acrotreta?)], Brogger [1882, p. 47] Do. ceratopygonum [Acrothele], Walcott [1902, p. 598] Do. chinensis [Obolus (Lingulella)], Walcott [1905a, pp. 328-329] Obolus chinensis. christianise [Orthis], Brogger [1882, p. 48] Eoorthis christianiiB (in part) and E. daunus (in part). Gagel [1890, pp. 10 and 34] Eoorthis daunus. Kjerulf [1865, pp. 1 and 3] Eoorthis christianise. Pompeckj [1902, p. 7] Eoorthis daunus. Remel6 [1881, p. 69] Do. Eemel6.[1885, p. 6] Do. Roemer [1885, pp. 36, 37, and 38] Do. christianise [Orthis (Plectorthis)], Moberg and Segerberg [1906, p. 69] Eoorthis christianire (in part only). The reference includes also E. daunus and E. tullbergi. Walcott [1905a, pp. 260-261] Eoorthis christianiaj. chromatica [Obolella], Billings [1861b, pp. 7-8] Obolella chromatica. Billings [1861c, p. 947] Do. Billings [1862e, p. 219] Do. Billings [1863, p. 284] Do. Billings [1876, pp. 176-178] Do. Ford [1881, p. 133] .' Do. Hall [1863, p. 132] Do. Hall [1867, p. 110] Do. Hall and Clarke [1892c, p. 67] Do. von Toll [1899, p. 27] (?) (See p. 592.) Walcott [1885a, pp. 115 and 117] Obolella crassa. Walcott [1886b, p. 112] Obolella chromatica. Walcott [1891a, p. 611] Do. Walcott [1899, p. 446] Do. Walcott [1905a, p. 313] Do. 40 CAMBRIAN BRACHIOPODA. Present reference. chuarensis [Obolus (Lingulella)], Walcott [1898b, p. 399] Obolus (Westonia) chuarensis. chuarensis [Obolus (Westonia)], Walcott [1901, p. 691] Do. cingulata [Kutorgina], Beecher [1891, pp. 345-346] Kutorgina cingulata. Bornemann [1891, p. 440] Kutorgina sardiniaensis. Davidson [1868, p. 312] Micromitra (Paterina) phillipsi. Davidson [1871, pp. 342-343] Do. Davidson [1883, p. 212] Do. Freeh [1897, PI. lA, figs. 6a-b] Kutorgina cingulata. Grabauand Shimer [1907, p. 209] Do. Hall and Clarke [1892a, PI. IV, figs. 11-13] Do. Hall and Clarke [1892c, p. 92] Do. von Toll [1899, pp. 26-27] Do. Walcott [1886b, pp. 102-104] Micromitra pusilla (in part), Micromitra (Paterina) phillipsi (in part), and Kutor- gina cingulata (in part). Walcott [1886b, pp. 102-104, PL IX, figs. 1-f] Kutorgina cingulata. Walcott [1886b, p. 103, PI. IX, figs. Ig-h] Rustella edsoni. Walcott [1891a, p. 609, PI. LXIX, figs. 1, la-f] Kutorgina cingulata. Walcott [1891a, p. 609, PI. LXIX, figs. Ig-h] Rustella edsoni. Walcott [1905a, pp. 308-309] Kutorgina cingulata. cingulata [Obolella], Billings [1863, p. 284, figs. 287a-b] '. . Do. Billings [1863, p. 284, fig. 287c] Rustella edsoni: cingulata [Obolella (Kutorgina)], Billings [1861b, pp. 8-9, figs. 8 and 10]. .Kutorgina cingulata. Billings [1861b, p. 8, fig. 9] Rustella edsoni. Billings [1861c, p. 948, figs. 347 and 349]. .Kutorgina cingulata. Billings [1861c, p. 948, fig. 348] Rustella edsoni. Billings [1862e, p. 220, figs. 347 and 349].. Kutorgina cingulata. Billings [1862e, p. 220, fig. 348]. Rustella edsoni. cingulata phillipsi [Kutorgina], Matley [1902, pp. 145-147] Micromitra (Paterina) phillipsi. cingulata pusilla [Kutorgina], Gronwall [1902, pp. 40-41] Micromitra pusilla. Linnarsson [1876, p. 25] Do. Matley [1902, pp. 146-147] Do. circe [Billingsella], Walcott [1901, p. 673] Quebecia circe. circe [Obolella], Billings [1872a, pp. 219-220] Do, Billings [1872c, pp. 357-358] Do. Walcott [1886b, p. 118, PL X, fig. 3] Obolella chromatica. The text includes Quebecia circe. Walcott [1886b, p. 118, PL X, fig. 3a] Quebecia circe. Walcott [1891a, p. 611, PL LXXI, fig. 8] Obolella chromatica. The text includes Quebecia circe. Walcott [1891a, p. 611, PL LXXI, fig. 3a] Quebecia circe. circe? [Obolella], Walcott [1891a, fig. 62, p. 611] Obolella crassa. circe [Quebecia], Walcott [1905a, pp. 320-321]. . .' Quebecia circe. circularis [Acrotreta], Moberg and Segerberg [1906, pp. 65-66] Acrotreta circularis. clarkei [Lingulella], Walcott [new] Lingulella clarkei. Clarkella Walcott [1908d, pp. 110-111] Clarkella. Walcott [1908e, PL XI, and pp. 142 and 148] Do. clarki [Dearbornia], Walcott [1908d, pp. 78-80] Dearbornia clarki. claytoni [Acrotreta], Walcott [1902, p. 583] Acrotreta claytoni. Qlitambonites planus retroflexus Schuchert [1897, p. 184] Billingsella retroflexa. Clitambonites (Gonambonites) plana retroflexa Matthew [1895b, p. 267]. . . Do. ccelata [Lingulella?], Matthew [1895a, p. 126] Botsfordia caelata. colleni [Acrothele], Walcott [new] Acrothele colleni. collicia [Leptobolus?], Matthew [1899b, p. 200] Lingulella collicia. collicia [Leptobolus], Matthew [1903, pp. 112-113] Do. collicia [Obolus (Lingulella)], Walcott [1902, p. 610] Do. collicia collis [Leptobolus], Matthew [1903, pp. 114-115] Do. collis [Leptobolus collicia], Matthew [1903, pp. 114-115] Do. coloradoensis [Billingsella], Grabau and Shimer [1907, p. 210] Billingsella coloradoensis. Schuchert [1897, p. 158] Do. Walcott [1899, pp. 450-4.51] Do. Walcott [1905a, pp. 231-234] Do. SYNONYMIC REFERENCES. 41 Present reference. coloradoensis [Orthis], Meek [1870, p. 425] Eoorthis desmoplevtra. Shumard [1860, p. 627] Billingsella coloradoensis. Columbiana [Crania?], von Huene [1899a, p. 141] Philhedra Columbiana. Columbiana [Crania], Matthew [1902c, pp. 108-109] Do. Columbiana [Crania?], Walcott [1889c, p. 441] Do. Columbiana [Philhedra?], von Huene [1899b, pp. 216 and 298] Do. Columbiana [Philhedra], Walcott [1908c, PL I, figs. 5 and 5a] Do. complexus [Obolella??], Hall and Clarke [1892c, p. 73] Obolus complexus. complexus [Obelus?], Barrande [1879b, Pis. XCV, CXI, CXIII, and CLII], ^ Do. complexus [Schmidtia??], Mickwitz [1896, pp. 19-20] ' Do. compta [Orthisina], Tate [1892, p. 185] Nisusia compta. concentrica [Acrotreta], Walcott [1902, p. 583] Acrotreta concentrica. concinna [Lingulella], Matthew [1901a, pp. 273-274] Lingulella concinna. Matthew [1903, pp. 203-204] Do. concinnus [Obolus (Lingulella)], Walcott [1902, pp. 608-609] Do. contraria [Discina], BaiTande [1868a, p. 104] Orbiculoidea contraria. Barrande [1868b. pp. 692-693] Do. Pompeckj [1896a, p. 4] Do. conula [Acrotreta], Walcott [1902, p. 584] Acrotreta conula. convexa [Acrotreta], Walcott [1902, p. 584] Acrotreta convexa. convexa [Ungula], Pander [1830, pp. 59 and 163] Obolus apoUinis quenstedti. convexa [Ungula plana or], Pander [1830, p. 163] Obolus apoUinis. convexus [Obolus (Lingulella) winona], Walcott [1901, p. 691] Lingulella winona convexa. coriace [Acrothele], Brogger [1878, p. 76] Acrothele coriacea. coriacea [Acrothele], Gronwall [1902, p. 40] Do. Linnars.son [1876, pp. 21-23].... Do. corrugata [Lingula?], Moberg and Segerberg [1906, p. 63] Lingulella lepis. Westergird [1909, p. 57] Do. corrugata [Orthis (Finkelnburgia) osceola], Walcott [1905a, p. 280] Finkelnburgia osceola corrugata. costata [Acrothele matthewi], Matthew [1895a, p. 128] Acrothele prima costata. Matthew [1902b, p. 399] Do. Matthew [1903, p. 104] Do. Crania Eichwald [1829, p. 273] Siphonotreta (in part). Crania? columbiana von Huene [1899a, p. 141] Philhedra columbiana. Crania columbiana Matthew [1902c, pp. 108-109] Do. Crania? columbiana Walcott [1889c, p. 441] Do. Crania sulcata Eichwald [1829, p. 274] Siphonotreta unguiculata. Crania unguiculata Eichwald [1829, p. 274] Do. Craniella?? sp. Walcott [1905b, pp. 4 and 6] Discinopsis? sulcatus. crassa [Acrothyra proavia], Matthew [1902b, pp. 389-390] Acrothyra proavia. Matthew [1903, p. 94] Do. crassa [Dicellomus], Hall [1873, p. 246] Obolella crassa. crassa [Obolella], Billings [1872a, p. 218] Do. Billings [1872c, p. 356] Do. ' Bornemann [1891, pp. 439-440] Obolus? zoppi. Ford [1878, p. 128] Obolella crassa. Ford [1881, pp. 131-133] Do. Ford [1886a, fig. 2, p. 466] Do. Gorham [] 905, PL I, figs, la-f] Obolella atlantica. Grabauand Shimer [1907, pp. 188-189] Obolella crassa. ' Hall and Clarke [1892a, PL III, figs. 5-7] Do. Hall and Clarke [1892c, p. 70] Do. Shaler and Foer.ste [1888, p. 27] Obolella atlantica. Walcott [1885b, p. 21] Obolella crassa. Walcott [1886b, p. 114] Do. Walcott [1891a, p. 612] Do. Walcott [1905a, p. 321] Do. crassa? [Obolella], Grabau [1900, pp. 619-620] Do. crassa [Obolella (Orbicula?)], Ford [1871, p. 33] Do. crassa [Orbicula?], Hall [1847, p. 290] Do. crassa elongata [Obolella], Walcott [new] Obolella crassa elongata. crassus [Obolus (Schmidtia)], Mickwitz [1896, pp. 187-193] Obolus (Schmidtia) crassus. crassus angulatus [Obolus (Schmidtia)], Mickwitz [1896, pp. 193-194] Do. 42 CAMBRIAN BRACHIOPODA. Present reference. crenistria [Iphidea], Walcott [1897b, p. 713] Micromltra (Paterina) crenistria. cuneata [Lingulella?], Matthew [1894, pp. 92-93] Lingulella grandis. cuneata [Lingulobolus affinis], Matthew [1895b, p. 262] Obolua (Lingulobolu.«) affinis. cuneolus [Lingulepis], Schuchert [1897, p. 259] Lingulella perattenuata (in part). Whitfield [1877, pp. 8-9] Lingulella cuneola. ■Whitfield [1880, p. 336] Do. cuneolus [Obolus (Lingulella)], Walcott [1899, p. 443] Do. Curticia Walcott [1905a, p. 319] Curticia. Walcott [1908e, PI. XI and pp. 142 and 143] ■ Do. Curticia elegantula Walcott [1905a, pp. 319-320] Curticia elegantula. curvata [Acrotreta], Walcott [1902, p. 584] Acrotreta curvate. cyane [Glossina], Schuchert [1897, p. 224] Obolus cyane. cyane [Lingula], Billings [1865a, p. 216] Do. D. dakotensis [Lingula], Meek and Hayden [1865, p. 3] Lingulella (Lingulepis) acuminata. \^Tiitfield [1880, pp. 337-338] : Do. Dalmanella melita Schuchert [1897, p. 202] Variety of Eoorthis desmopleura. damesi [Obolus (Lingulella)], Walcott [1905a, p. 329] Obolus damesi. (See Lingulella damesi, p. 489.) dartoni [Obolus (Westonia)], Walcott [1908d, p. 67] Obolus (Westonia) dartoni. daunus [Orthis (Plectorthis)], Moberg and Segerberg [1906, p. 69] Eoorthis daunus. Walcott [1905a, p. 261] Do. I Davidsonella Munier-Chalmas [1880] Davidsonella, not Neobolus. Waagen [1885a, pp. 762-764] Neobolus. Davidsonella linguloides Waagen [1885a, pp. 764-766] Neobolus warthi. Davidsonella squama Waagen [1885a, pp. 766-767] '. Do. davidsoni [Lingula], Barrande [1879b, PI. CIV, figs, viii: 1-4] Lingulella davidsoni. davisi [Lingula], McCoy [1851b, pp. 405^06] Lingulella davisi. McCoy [1854, p. 252] Do. davisi [Lingula cf .], Schmidt [1881, p. 17, fig. 5] Obolus (Mickwitzella) siluricus. davisi [Lingulella], Davidson [1868, pp. 304 and 306] Lingulella davisi. Hall and Clarke [1892a, p. 232] Do. Hall and Clarke [1892b, p. 548] : Do. Hall and Clarke [1892c, pp. 56 and 57] Do. Meek [1871, pp. 186-187] Do. Salter [1866b, pp. 333-334]. .• Do. davisii [Lingulella], Davidson [1866, pp. 56 and 57] Do. Hall [1873, PL XIII, fig. 4] Do. Roemer [1876, PI. II, figs. 5a-c] Do. Salter [1867, pp. 44 and 52] Do. Salter and Etheridge [1881, pp. 537-538] Do. davisii [Lingulella cf.], Kayser [1897, p. 280] Do. Matthew [1902b, pp. 407-408] - Do. Matthew [1903, p. 203] Do. davisii [Obolus (Lingulella)], Walcott [1898b, pp. 394 and 395] Do. dawsoni [Lingula?], Matthew MS. [1884] Lingulella ferruginea. Walcott [1884a, p. 15] Do. dawsoni [Lingulella], Hall and Clarke [1892c, p. 58] Do. Matthew [1886, pp. 33-34, PI. V, figs. 9, 9a-c] Lingulella martinensis. The text includes L. ferruginea. Matthew [1886, pp. 33-34, PI. V, fig. 9d] Lingulella ferruginea. The text includes L. martinensis. Dearbornia Walcott [1908d, p. 78] Dearbornia. Walcott [1908e, PL XI, and pp. 142 and 146] Do. Dearbornia clarki Walcott [1908d, pp. 78-80] Dearbornia clarki. decipiens [Acrothele], Walcott [1897b, p. 716] Acrothele decipiens. decipiens [Obolus mcconnelli], Walcott [new] Obolus mcconnelli decipiens. definita [Acrotreta], Walcott [1902, pp. 584-585] Acrotreta definita. Delgadella Walcott [1908e, PI. XI, and pp. 142 and 144] Delgadella. delgadoi [Lingulella], Walcott [new] Lingulella delgadoi. depressa [Acrotreta], Walcott [1908c, p. 245] Acrotreta:depressa. depressa [Acrotreta gemma], Matthew [1902c, p. 109] Do. Walcott [1889c, pp. 441^42] Do. SYNONYMIC EEB^ERENCES. 43 Present reference. descendens [Acrotreta ophirensis], Walcott [1908d, p. 95] Acrotreta ophirensis descendens. desiderata [Billingsia], Ford [lS86a, pp. 466 and 467] Elkania desiderata. desiderata [Elkania], Ford [1886b, p. 325] Do. Hall and Clarke [1892a, PI. Ill, figs. 13 and 14] Do. Hall and Clarke [1892c, pp. 76 and 77] Do. desiderata [Obolella], Billings [1862d, pp. 69-70] Do. Davidson [1868, p. 309] Do. desiderata [Obolella?], Walcott [1886b, p. Ill] Do. desideratus [Obolus (Lingulella)], Walcott [1898b, pp. 399^00] Lingulella desiderata. Walcott [1899, pp. 445-446, PI. LX, fig. 2] Do. Walcott [1899, pp. 445-446, PL LX, fig. 2a] Obolus rotundatus. desmopleura [Orthis], Meek [1872, p. 295] Eoorthis desmopleura. desmopleura [Orthis (Plectorthis)], Walcott [1905a, p. 261] Do. desmopleura nympha [Orthis (Plectorthis)], Walcott [1905a, p. 262] Eoorthis desmopleura nympha. desquamata [Avicula?], Hall [1847, p. 292] Obolella crassa. desquamata [Obolella], Billings [1872a, p. 218] Do. Billings [1872c, p. 356] Do. diablo [Orthis (Plectorthis)], Walcott [1905a, p. 262] Eoorthis? diablo. dice [Billingsella], Walcott [1905a, p. 234] Billingsella dice. Dicellomus Grabau and Shimer [1907, p. 189] Dicellomus. Hall [1873, p. 246] Do. Hall and Clarke [1892a, pp. 240-241] Do. Hall and Clarke [1892c, pp. 66-73] Do. Walcott [1899, p. 446] Do. Walcott [1905a, pp. 312-313] Do. Wal ;ott [1908e, PI. XI, and pp. 142 and 144] Do. Dicellomus appalachia Walcott [1905a, p. 314] Dicellomus appalachia. Dicellomus crassa Hall [1873, p. 246]. Obolella crassa. Dicellomus nanus Walcott [1899, p. 447] Lingulella desiderata (in part) and Dicello- mus nanus (in part). Walcott [1905a, pp. 314-315] Dicellomus nanus. Dicellomus parvus Walcott [1905a, pp. 315-316] , Dicellomus parvus. Dicellomus pectenoides Walcott [1901, p. 673] Dicellomus pectenoides. Walcott [1905a, p. 316] Do. Dicellomus polita Hall [1873, p. 246] Dicellomus politus. Dicellomus politus Grabau and Shimer [1907, pp. 189-190] Do. Walcott [1899, pp. 443 and 446] Do. Walcott [1905a, pp. 313 and 316-318] Do. Dicellomus prolificus Walcott [1908d, p. 77] Dicellomus prolificus. Dicellomus sp. undt. Walcott [1905a, p. 319] Dicellomus sp. undt. dichotoma [Acrothele?], Walcott [18S4b, pp. 14-15] Acrothele dichotoma. dichotoma [Acrotreta], Hall and Clarke [1892c, pp. 100 and 103] Do. Walcott [1886b, p. 107] Do. Discina buchii Eichwald [1860, p. 914] Helmersenia ladogensis (in part) and Key- serlingia buchi (in part). Discina contraria Barrande [1868a, p. 104] Orbiculoidea contraria. Barrande [1868b, pp. 692-693] Do. Pompeckj [1896a, p. 4] Do. Discina labiosa Salter [1866a, p. 285] Acrotreta sagittalis. Discina microscopica Shumard [1861, p. 221] .Acrotreta microscopica. Discina pileolus Davidson [1868, pp. 312-313] Orbiculoidea pileolus. Davidson [1871, p. 344] Do. (Hicks MS.) Salter [1866a, p. 285] Do. Discina pileolus? Hicks [1871, PL XV, figs. 12 and 12a] Stenotheca pileolus, a gastropod. Discina varians Barrande [1868a, pp. 103-104] Orbiculoidea varians. Barrande [1868b, p. 692] Do. Pompeckj [1896a, p. 4] Do. Discina sp. Miquel [1893, p. 9] Acrothele bergeroni. Miquel [1894a, p. 106] Do. Miquel [1894b, p. 10] Do. Miquel [1895, p. 10] Do. 44 CAMBRIAN BRACHIOPODA. Presenl reference. Discina?sp. Kjerulf [1873, p. 83, figs. 12 and 13] Obolella (Glyptias) favosa?. Discina (Acrotreta?) ceratopygarum Brogger [1882, p. 47] Acrothela ceratopygarum. Discina (Orbicula) primiseva de Vemeuil and Barrande [I860, p. 532] Acrothele primKva. Discinolepis Hall and Clarke [1892a, p. 247] Discinolepis. Hall and Clarke [1892b, p. 563] Do. Hall and Clarke [1892c, p. 90] Do. Waagen [1885a, pp. 749-750] Do. Walcott [1908e, PI. XI, and pp. 142 and 146] Do. Discinolepis granulata Hall and Clarke [1892a, p. 247] Discinolepis granulata. Hall and Clarke [1892b, p. 563] Do. Hall and Clarke [1892c, p. 90] Do. Waagen [1885a, pp. 7.50-751] Do. Waagen [1891, PI. II, figs. 15 and 16] Do. Discinopsis Hall and Clarke [1892a, pp. 250-251] Discinopsis. Hall and Clarke [1892b, pp. 566-567] Do, Hall and Clarke [1892c, pp. 105-106] Do. Walcott [1908e, PL XI, and pp. 142 and 146] Do.. Discinopsis gulielmi Hall and Clarke [1892a, PI. Ill, figs. 20 and 21] Discinopsis gulielmi. Hall and Clarke [1892c, p. 105] • Do. Discinopsis sulcatus Walcott [1906, pp. 568-569] Discinopsis? sulcatus. discoida [Obolella], Hall and Whitfield [1877, p. 205] Obolus discoideus. discoidea [Obolella?], Hall and Clarke [1892c, p. 69] Do. | discoidea [Obolella], Walcott [1884b, p. 14] Do. discoidea [Obolella?], Walcott [1886b, p. Ill] Do. discoideus [Obolus (Lingulella)], Walcott [1901, p. 673] Do. discus [Obolus], Matthew [1902c, p. 94] Lingulella triparilis. discus [Obolus (Eoobolus)], Matthew [1903, pp. 138-139] Do. dolata [Lingula], Sardeson [1896, p. 95] Obolus dolatus. doris [Orthis (Plectorthis)], Walcott [1905a, pp. 262-263] ■ Eoorthis doris. dougaldensis [Protorthis (Loperia)], Walcott [1905a, pp. 287-288] Protorthis (Loperia) dugaldensis. dubia [Siphonotreta?], Walcott [new] Siphonotreta dubia. dubius [Obolus (Lingulella)], Walcott [1898b, p. 401] Lingulella dubia. edsoni [Rustella], Walcott [190.5a, pp. 311-312] Rustella edsoni. eggegrundensis [Acrotreta], Walcott [1905a, pp. 299-300] Acrotreta eggegrundensis. Wiman [1902, p. 55] Do. eichwaldi [Obolus], Mickwitz [1896, pp. 154-155] Obolus eichwaldi. elegans [Obolus], Mickwitz [1896, pp. 157-158] Obolus elegans. elegantula [Curticia], Walcott [1905a, pp. 319-320] Curticia elegantula. elegantula [Strophomena (Eostrophomena)], Walcott [1905a, pp. 256-257] . Eostrophomena elegantula. Elkania Ford [1886b, p. 325] Elkania. Hall and Clarke [1892a, p. 241] Do. Hall and Clarke [lS92b, p. 557] Do. Hall and Clarke [1892c, pp. 75-78] Do. Walcott [1905a, pp. 321-323] Elkania (in part) and Obolus (Fordinia) (in part). Walcott [1908e, PI. XI, and pp. 142 and 144] Elkania. Elkania ambigua Ford [1886b, p. 325] Elkania ambigua. Hall and Clarke [1892c, p. 78] Do. Elkania bellula Walcott [1905a, p. 323] ...Obolus (Fordinia) bellulus. Elkania desiderata Ford [1886b, p. 325] Elkania desiderata. Hall and Clarke [1892a, PI. Ill, figs. 13 and 14] Do. Hall and Clarke [1892c, pp. 76 and 77] Do. Elkania ida Ford [1886b, p. 325] Elkania ida. Elkania pretiosa Ford [1886b, p. 325] Acrothele pretiosa. ella [Lingulella], Hall and Clarke [1892c, p. 58, figs. 19 and 21] Obolus (Westonia) ella. The text includes. also specimens representing Lingulella dubia. Hall and Clarke [1892c, p. 58, fig. 20] Lingulella dubia. Pack [1906, p. 295] Obolus (Westonia) ella. Walcott [1886b, pp. 97-98, PI. VII, fig. 2; PI. VIII, figs. 4, 4a, 4d-e] Obolus (Westonia) ella. The text includes also specimens representing Lingulella. dubia. SYNONYMIC REFERENCES. 45 Present reference. ella[Lingulella],Walcott [1886b, pp. 97-98, PI. VIII, figs. 4b and 4c] Lingulella dubia. The text includes Obolus (Westonia) ella. Walcott [1891a, p. 607, PI. LXVII, figs. 2, 2a-b, and 2e]. .Obolus (Westonia) ella. The text includes also specimens representing Lingulella dubia. Walcott [1891a, p. 607, PI. LXVII, figs. 2c-d] Lingulella dubia. The text includes Obo- lus (Westonia) ella. ella [Lingulella (Westonia)], Grabau and Shimer [1907, p. 193] Obolus (Westonia) ella. ella [Lingulepis], Hall and 'Whitfleld [1877, p. 232] Do. Walcott [1897a, p. 404] Do. ella [Obolus], Matthew [1902c, pp. 96 and 110] Do. ella [Obolus (Lingulella)], Walcott [1898b, PI. XXVIII, figs. 5-8] Do. ella [Obolus (Westonia)], Walcott [1901, p. 691] Do. ella onaquiensis [Obolus (Westonia)], Walcott [190Sd, pp. 67-68] Obolus (Westonia) ella onaquiensis. ellipticus [Obolus (Schmidtia) obtusus], Mickwitz [1896, pp. 177-178] Obolus (Schmidtia) obtusus. ellsi [Obolus (Lingulella)], Walcott [1898b, p. 402] Lingulella ellsi. elongata [Obolella crassa], Walcott [new] Obolella crassa elongata. elongatus [Obolus (Westonia)], Walcott [1908d, p. 68] Obolus (Westonia) elongatus. emmonsi [Acrotreta], Walcott [1905a, p. 300] Acrotreta emmonsi. endlichi [Micromitra sculptilis], Walcott [1908d, p. 56] Micromitra sculptilis endlichi. Eoobolus Matthew [1902c, p. 97] Lingulella. (Eoobolus) [Obolus], Matthew [1903, pp. 135-136] Obolus (in part) and Lingulella (in part). (Eoobolus) discus [Obolus], Matthew [1903, pp. 138-139] Lingulella triparilis. (Eoobolus) triparilis [Obolus], Matthew [1903, pp. 136-137] Do. Eoorthis Walcott [1908d, pp. 102-104] Eoorthis. Walcott [1908e, PI. XI, and pp. 142 and 148] Do. Eoorthis newberryi Walcott [1908d, p. 105] Eoorthis newberryi. Eoorthis thyone Walcott [1908d, pp. 105-106] Eoorthis thyone. Eoorthis zeno Walcott [1908d, p. 106] Eoorthis zeno. Eostrophomena Walcott [1908e, PL XI, and pp. 142 and 148] Eostrophomena. (Eostrophomena) [Strophomena], Walcott [1905a, p. 256] Do. (Eostrophomena) elegantula [Strophomena], Walcott [1905a, pp. 256-257]. .Eostrophomena elegantula. (Eostrophomena) walcotti [Strophomena], Moberg and Segerberg [1906, p. 71] Do.' erecta [Nisusia (Jamesella)], Walcott [1905a, p. 253] Nisusia (Jamesella) erecta. eros [Obolus (Lingulepis)], Walcott [1905a, p. 333] Lingulella (Lingulepis) eros. eryx [Acrothele matthewi], Walcott [1905b, p. 11] Acrothele matthewi eryx. escasoni [Lingulella(?)], Matthew [1901a, pp. 270-273] Obolus (Westonia) escasoni. escasoni [Obolus (Westonia)], Walcott [1901, p. 691] Do. escasoni [Westonia], Matthew [1903, pp. 206-209] Do. esthonia [Schizambon ?], Walcott [new] Schizambon ? esthonia. etheridgei [Huenella], Walcott [1908d, pp. 109-110] Huenella etheridgei. etheridgei [Platyceras], Tate [1892, p. 184] Micromitra (Paterina) etheridgei. euglyphus [Obolus (Lingulella)], Walcott [1898b, pp. 402-403] Obolus (Westonia) euglyphus. euglyphus [Obolus (Westonia)], Walcott [1901, p. 691] Do. (Euobolus) [Obolus], Mickwitz [1896, pp. 129 and 133] Lingulella (in part) and Obolus (in part). eurekensis [Orthis?], Schuchert [1897, p. 286] Orusia ? eurekensis. eurekensis [Orthis], Walcott [1884b, pp. 22-23] Do. eurekensis [Orthis (Orusia?)], Walcott [1905a, p. 277] Do. eurekensis [Protorthis?], Hall and Clarke [1892c, p. 232] Do. excelsis [Trematobolus], Walcott [1908d, pp. 80-81] Trematobolus excelsis. exigua [Lingulepis starri], Matthew [1903, pp. 197-198] Lingulella (Lingulepis) exigua. exporecta [Orthis], Linnarsson [1876, pp. 12-13] Do. exporrecta [Billingsella], Walcott [1905a, pp. 234-236] Billingsella exporrecta. exporrecta [Orthis], Kayser [1883, p. 35] Do. Wallerius [1895, p. 66] Do. exporrecta rugosicostata [Billingsella], Walcott [1905a, p. 236] Billingsella exporrecta rugosicostata. extenuatus [Obolus (Schmidtia) obtusus], Mickwitz [1896, pp. 178-179] Obolus (Schmidtia) obtusus. exungui [Lingula aff.], Gtirich [1896, p. 214] Lingulella siemiradzkii. exunguis [Lingula cf .], Giirich [1892, p. 69] Do. Siemiradzki [1886, p. 672] Do. 46 CAMBRIAN BRACHIOPODA. F. Present reference favosa [Lingula(?)], Linnarsson [1869a, pp. 356-357] Obolella (Glyptias) favosa. Linnarsson [1869b, p. 406] Do. favosa [Lingulella{?) cf. Lingula], Matthew [1888, pp. 28-29] Botsfordia pulchra. favosa [Obolella (Glyptias)], Walcott [1901, pp. 675-676] Obolella (Glyptias) favosa. feistmanteli [Lingula], Barrande [1879b, Pis. CVI and CX] Obelus feistmanteli. terruginea [Lingulella], Davidson [1868, pp. 306-307] Lingulella ferruginea. Davidson [1871, pp. 336-337] Do. Davidson [1883, PL XVII, fig. 35] Do. Delgado [1904, pp. 368-369] Lingulella delgadoi. Matthew [1903, p. 108] ' Lingulella ferruginea. Salter [Salter and Hicks, 1867, p. 340] Do. Salter and Etheridge [1881, p. 538] Do. ferruginea [Lingulella cf .], Kayser [1897, p. 280] Do. ferruginea ovalis [Lingulella], Davidson [1868, p. 307] Do. Hicks [Salter and Hicks, 1867, p. 341] Do. festinata [Billingsella], Hall and Clarke [1892c, p. 230] Nisusia festinata. festinata [Nisusia], Grabau and Shimer [1907, p. 211] Do. Walcott [1905a, pp. 249-251] Do. festinata [Orthisina], Billings [1861b, p. 10] Do. Billings [1861c, p. 949] Do. Billings [1862b, p. 105] Do. Billings [1862e, p. 221] Do. | Billings [1863, p. 284, figs. 289a-c] Do. Walcott [1886b, pp. 120-121] Do. Walcott [1891a, p. 613] Do. festinata transversa [Nisusia], Walcott [1905a, p. 251] Nisusia festinata transversa. finkelnburgi [Orthis (Finkelnburgia)], Walcott [1905a, pp. 278-279] Finkelnburgia finkelnburgi. Finkelnburgia Walcott [1908e, PI. XI, and pp. 142 and 148] Finkelnburgia. (Finkelnburgia) [Orthis], Walcott [1905a, pp. 277-278] Do. (Finkelnburgia) finkelnburgi [Orthis], Walcott [1905a, pp. 278-279] Finkelnburgia finkelnburgi. (Finkelnburgia) osceola [Orthis], Walcott [1905a, p. 279] Finkelnburgia osceola. (Finkelnburgia) osceola corrugata [Orthis], Walcott [1905a, p. 280] Finkelnburgia osceola corrugata. finlandensis [Obolus (Westonia)], Walcott [1902, pp. 611-612] Obolus (Westonia) finlandensis. flumenis [Leptobolus], Matthew [1903, pp. 189-190] Lingulella flumenis. (Fordinia) [Obolus], Walcott [1908d, pp. 64-65] Obolus (Fordinia). Walcott [1908e, Pl.XI, and pp. 142 and 144] Do. (Fordinia) gilberti [Obolu.s], Walcott [1908d, p. 65] Obolus (Fordinia) gilberti. (Fordinia) perfectus [Obolus], Walcott [1908d, pp. 65-66] Obolus (Fordinia) perfectus. formosa [Causea], Wiman [1902, pp. 53-54] Mickwitzia formosa. fragilis [Obolus (Lingulella)], Walcott [1898b, p. 404] -. Obolus fragilis. franklinensis [Obolus (Lingulella)], Walcott [1898b, pp. 404-405] Lingulella franklinensis. fuchsi [Lingulella], Redlich [1899, p. 7] Lingulella fuchsi. fuchsi [Obolus (Lingulella)], Walcott [1905a, p. 332] Do. G. gamagei [Acrothele], Grabau [1900, pp. 615-617] Acrothele gamagei. Grabau and Shimer [1907, p. 200] Do. Shimer [1907, pp. 176 and 177] Do. gamagei [Obolella], Hobbs [1899, pp. 114-115] Do. gemma [Acrotreta], Billings [1865a, pp. 216-217] Acrotreta gemma. Grabau and Shimer [1907, p. 199] Acrotreta primaeva. Hall and Clarke [1892c, p. 102, fig. 55] Acrotreta curvata. Hall and Clarke [1892c, p. 102, figs. 56 and 57] Acrotreta idahoensis alta. Walcott [1884b, pp. 17-18] Acrotreta attenuata (in part), A. pyxidi- cula (in part), A. curvata (in part), and A. idahoensis (in part). The text in- cludes all four species, but the last two were the only ones figured. Walcott [1884b, pp. 17-18, PL I, figs, la-b] Acrotreta idahoensis alta. Walcott [1884b, pp. 17-18, PL I, figs. Id-e] Acrotreta curvata. SYNONYMIC REFERENCES. 47 Present reference. gemma [Acrotreta], Walcott [1886b, pp. 98-99] Acrotreta attenuata (in part), A. pyxidicula (in part), and A. primaeva (in part). The text includes all three species, but the last was the only one figured. Walcott [1886b, pp. 98-99, PL VIII, figs. 1, la-b] Acrotreta primisva. Walcott [1891a, p. 608] Acrotreta attenuata (in part), A. pyxidicula (in part), A. curvata (in part), A. idahoen- sis alta (in part), and A. primeeva (in part). The text includes all five species, but the last three were the only ones fig- ured. Walcott [1891a, p. 608, PI. LXVII, figs. 5 and 5a] Acrotreta idahoensis alta. Walcott [1891a, p. 608, PL LXVII, fig. 5b] .Acrotreta curvata. Walcott [1891a, p. 608, PL LXVII, figs. 5c-e] Acrotreta primaeva. Walcott [1899, p. 449] Acrotreta attenuata (in part), A. pyxidicula (in part), A. curvata (in part), A. idaho- ensis alta (in part), and A. primseva (in part). The text includes all five species, but the last three were the only ones fig- ured. Walcott [1899, p. 449, PL LXII, figs. 2, 2b, and 2d]. . .Acrotreta primeeva. Walcott [1899, p. 449, PL LXII, figs. 2a and 2c] Acrotreta idahoensis alta. Walcott [1899, p. 449, PL LXII, fig. 2e] Acroti-eta curvata. gemma [Bicia], Walcott [1901, pp. 678-680] Bicia gemma. gemma [Obolella], BilHngs [1872a, pp. 218-219] Do. Billings [1872c, p. 355] Do. Hall and Clarke [1892c, pp. 69 and 71] Do. Walcott [1886b, pp. 116-117] Do. Walcott [1891a, p. 612] Do. gemma depressa [Acrotreta], Matthew [1902c, p. 109] Acrotreta depressa. Walcott [1889c, pp. 441-442].. 1 Do. gemmula [Acrotreta], Matthew [1894, pp. 87-88] Acrotreta gemmula. Matthew [1895a, p. 126] Do. Matthew [1903, p. 97] Do. gemmula [Obolella?], Matthew [1892, pp. 41-42] Lingulella ferruginea. gemmulus [Leptobolus], Matthew [1903, pp. 190-192] Do. gemmulus [Obolus (Lingulella)], Walcott [1901, p. 673] Do. genei [Lingulella], Pack [1906, p. 295] Lingulella dubia. Genre? sp. nebulosa Barrande [1868a, pp. 105-106] Orbiculoidea contraria. Barrande [1868b, pp. 693-694] Do. gilberti [Obolus (Fordinia)], Walcott [1908d, p. 65] Obolus (Fordinia) gilberti. girtyi [Linnarssonella], Walcott [1902, pp. 602-603] Linnarssonella girtyi. Glossina acuminata Hall and Clarke [1892a, PL I, figs. 10 and 11] Lingulella (Lingulepis) acuminata sequens. (Glossina) acuminata [Lingula], Hall and Clarke [1892c, PL I, figs. 1 and 2] . . Do. Glossina cyane Schuchert [1897, p. 224] Obolus cyane. (Glyptias) [Obolella], Walcott [1901, p. 675] Obolella (Glyptias). Walcott [1908e, PL XI, and pp. 142 and 145] Do. (Glyptias) favosa [Obolella], Walcott [1901, pp. 675-676] Obolella (Glyptias) favosa. (Gonambonites) plana retroflexa [Clitambonites], Matthew [1895b, p. 267]. .Billingsella retroflexa. gracia [Acrotreta], Walcott [1902, pp. 586-587] Acrotreta gracia. grandis [Leptobolus], Matthew [1894, pp. 91-92] Lingulella grandis. grandis [Leptobolus cf.], Matthew [1902c, p. Ill] Does not equal Lingulella gi-andis. It is not referred in this monograph. grandis [Lingulella laevis], Matthew [1903, pp. 200-201] Lingulella Isevis grandis. granulata [Acrothele], Davidson [1883, p. 214] Acrothele (Redlichella) granulata.. Hall and Clarke [1892c, pp. 100-101] Do. Linnarsson [1876, p. 24] Do. Linnarsson [1877, pp. 373-374] Do. Swanston [1877, PL VII, figs. 20a-c] Do. Swanston [1886, PL VII, figs. 20a-c] Do. Walcott [1886b, p. 109] Do. 48 CMIBRIAN BRACHIOPODA. Present reference. granulata [Discinolepis], Hall and "Clarke [1892a, p. 247] Discinolepis granulata. Hall and Clarke [1892b, p. 563] Do. Hall and Clarke [1892c, p. 90] Do. Waagen [1885a, pp. 750-751] Do. Waagen [1891, PI. XI, figs. 15 and 16] Do.- granulata [Kutorgina], Matthew [1899a, p. 189] Kutorgina granulata. Matthew [1899e, p. 98] Do. granulata [Mobergia], Redlich [1899, pp. 5-6] Botsfordia granulata. granvillensis [Lingulella], Delgado [1904, pp. 367-368] Lingulella delgadoi. Hall and Clarke [1892c, p. 58] Lingulella granvillensis. Oehlert [1889, p. 1138] Do. Walcott [1887, pp. 188-189] Do. Walcott [1891a, pp. 607-608] Do. gran\nllensis [Lingulella cf .], Matthew [1895a, pp. 114-115] Lingulella martinensis. gregwa [Lingulella], Matthew [1899b, pp. 199-200] Lingulella (Lingulepis) gregwa. gregwa [Lingulepis], Matthew [1903, pp.. 56-57 and 126-131] Do. gregwa [Obolus (Lingulepis)], Walcott [1901, pp. 692-694] Lingulella atava (in part), L. cania (in part), L. tumida (in part), Lingulella (Lingulepis) gregwa (in part), and L. (L.) ' exigua(inpart). gregwa robusta [Lingulepis], Matthew [1903, pp. 57 and 131] Lingulella (Lingulepis) gregwa robusta. groomi [Obolella], Matley [1902, pp. 137 and 139] Obolella groomi . gulielmi [Acrotreta?], Matthew [1886, pp. 37-39] Discinopsis gulielmi. gulielmi [Discinopsis], Hall and Clarke [1892a, PI. Ill, figs. 20 and 21].... Do. Hall and Clarke [1892c, p. 105] Do. H. hambxiTgensis [Orthis], Walcott [1884b, p. 73] Eoorthis desmoplevira ?. harlanensis [Billingsella], Walcott [1905a, p. 236] Wimanella harlanensis. hastingsensis [Orthis (Plectorthis)], Walcott [1905a, p. 263] Eoorthis hastingsensis. hawkei [Lingula], Roualt Not taken up in this monogi'aph ; it does not equal Mickwitzia sp. undt. hawkei? [Lingula], Bomemann [1891, p. 439] Mickwitzia sp. undt. haydeni [Micromitra], Walcott [1908d, pp. 55-56] Micromitra haydeni. hayesi [Obolus (Lingulella)], Walcott [1898b, pp. 405-406] Lingulella hayesi. heberti [Lingulella], Barrois [1882, pp. 185-186] Lingulella heberti. helena [Obolus (Lingulella)], Walcott [1898b, p. 406] Lingulella helena. helena [Protorthis], Walcott [1905a, p. 282] Protorthis helena. Helmersenia Hall and Clarke [1892a, p. 254] Helmersenia. Hall and Clarke [1892b, p. 570] Do. Hall and Clarke [1892c, p. 119] Do. Oehlert [1887, p. 1264] Do. Pander [1861, columns 48-49] Do. Walcott [1908e, PL XI, and pp. 142 and 143] Do. Zittel [1880, p. 666] Do. Helmersenia jeremejewi Dall [1877, p. 31] Helmersenia ladogensis. Oehlert [1887, p. 1264] Do. Helmersenia sp.? Hall and Clarke [1892a, p. 254] Do. Hall and Clarke [1892c, p. 119] Do. Pander [1861, columns 48^9] Do. hera [Acrothele subsidua], Walcott [1908d, p. 87] Acrothele subsidua hera. hicksi [Billingsella], Walcott [1905a, p. 237] Billingsella hicksi. hicksi [Orthis], Kayser [1883, p. 35] Do. Linnarsson [1876, pp. 13-14] Billingsella exporrecta rugosicostata. hicksii [Orthis], Davidson [1868, p. 314] Billingsella hicksi. Davidson [1869, p. 230] Do. highlandensis [Billingsella], Walcott [1905a, pp. 237-238] Billingsella hjghlandensis. highlandensis [Orthis?], Walcott [1886b, pp. 119-120] Do. Walcott [1891a, p. 612] Do. Huenella Walcott [1908d, p. 109] Huenella. Walcott [1908e, PL XI and pp. 142 and 148] Do. Huenella etheridgei Walcott [1908d, pp. 109-110] Huenella etheridgei. Huenella lesleyi Walcott [1908d, p. 110] Huenella lesleyi. Huenella vermontana Walcott [new] Huenella vermontana. SYNONYIVCIC REFERENCES. 49 Present reference, humeratus [Obolus (Schmidtia) acuminatus], Mickwitz [1896, pp. 184-186]. .Obolus (Schmidtia) acuminatus. humillima [Lingula], Barrande [18C8a, p. 101] Lingulella? humillima. Barrande [1868b, p. 691] Do. himnebergeiisis [Protortliis?], Moberg and Segerberg [1906, pp. 70-71] Protorthis? hunnebergensis. I. ida [Billingsia?], Ford [1886a, p. 467] ELkania ida. ida [Elkania], Ford [lS86b, p. 325] Do. ida [Obolella], Billings [1862d, p. 71] Do. ida? [Obolella], Dawson [1888a, p. 55] Acrotreta sagittalis. Dawson [188Sb, p. 55] Do. ida [Obolella?], Walcott [1886b, p. Ill] Elkania ida. idahoensis [Acrotreta], Walcott [1902, p. 587] Acrotreta idahoensis. idalioensis [Acrotreta cf .], Walcott [new] Acrotreta cf . idahoensis. idahoensis alta [Acrotreta], Walcott [1902, p. 588] Acrotreta idahoensis alta. idahoensis sulcata [Acrotreta], Walcott [1902, p. 588] Acrotreta idahoensis sulcata. iddingsi [Orthis (Plectorthis)], Walcott [190.5a, p. 264] Eoorthis iddingsi. inchoans [Acrothele], Matthew [1902b, p. 404] Acrotreta inchoans. Matthew [1903, p. 103] Do. inchoans [Acrotreta], Pompeckj [1896a, p. 3] Do. inchoans [Lingula], Barrande [1868a, p. 102] Do. Barrande [1868b, p. 692] , Do. indianola [Orthis (Plectorthis)], Walcott [1905a, pp. 264-265] Eoorthis indianola. indianola [Plectorthis], Grabau and Shimer [1907, pp. 251-252] Do. inflata [AcrothjTa?], Matthew [1901b, p. 304] Acrotreta inflata. inflata [Acrotreta], Walcott [1902, pp. 588-589] Do. inflata [Lingulella?], Matthew [1886, p. 33] Do. Matthew [189.5a, p. 127] Do. Matthew [1898a, p. 128] Do. inflata [Lingulella (Acrothyra?)], Matthew [1902b, p. 390] Do. inflata ovalis [Lingulella?], Matthew [1895a, p. 127] _ Do. inflatus [Obolus?], Westergard [1909, p. 76] Obolus? inflatus. ingricus [Obolus], Eichwald [1829, p. 274] Obolus apollinis ingricus. Eichwald [1843b, pp. 140-141] Do. Eichwald [I860, pp. 926-927] Do. von Leuchtenberg [1843, p. 16] Do. ingricus [Obolus apollinis], Mickwitz [1896, pp. 137-140] Do. ino [Obolus (Lingulella)], Walcott [1898b, pp. 406^07] Lingulella ino. inomatus [Obolus triangularis], Mickwitz [1896, pp. 148-149] Obolus triangularis. insignis [Trematobolus], Hall and Clarke [1892a, p. 252] Trematobolus insignis. Hall and Clarke [1892b, p. 568] Do. Matthew [1893a, pp. 276-279] Do. Matthew [1894, pp. 88-90] Do. Matthew [189.5a, pp. 122-125] Do. Matthew [1895c, p. 95] Do. Matthew [1898b, p . 35] Do. insons [Lingula], Barrande [1879b, PI. CV, figs, x: 1-6] Lingulella? insons. insulse [Leptobolus atavus], Matthew [1903, pp. 110-112] Lingulella atava insulse. intermedia [Acrothele], Gronwall [1902, p. 39] Acrothele intermedia. Linnarsson [1879, pp. 25-27] Do. inyoeusis [Wimanella], 'Walcott [1908d, p. 99] Wimanella inyoensis. iole [Lingula], Billings [1865a, p. 215] Lingulella iole. Iphidea Baly [1865] Iphidea, not Micromitra. (See p. 332.) Billings [1872b, pp. 477-478] Micromitra. Billings [1874, p. 76] Do. Dall [1877, p. 39] Do. Grabau and Shimer [1907, p. 201] Micromitra (Paterina) (in part) and M. (Iphidella) (in part), not true Micromitra. Hall and Clarke [1892a, p. 249] Micromitra or Micromitra (Paterina). Hall and Clarke [1892b, p. 56.5] Do. Hall and Clarke [1892c, pp. 97-98] Micromitra. Linnarsson [1876, p. 26] Do. Oehlert [1887, p. 1270] Do. 62667°— VOL 51, pt 1—12 4 50 CAIvIBRIAN BRACHIOPODA. Present reference. Iphidea Schuchert [1897, p. 233] Micromitra and Micromitra (Paterina). Walcott [1886b, pp. 100-101] Micromitra. Walcott [1897b, pp. 707-711] Micromitra (in part), M. (Paterina) (in part), and M. (Iphidella) (in part). Walcott [1899, pp. 447-448] Micromitra. Iphidea alabamaensis Walcott [1897b, pp. 713-714] Micromitra alabamaensis. Iphidea bella Billings [1872b, pp. 477^78] Micromitra (Paterina) bella. Billings [1874, p. 76] Do. Billings [1882, p. 13] Do. Clark and Mathews [1906, p. 252] Do. Grabau and Shimer [1907, p. 201] Do. Hall and Clarke [1892a, p. 249] Micromitra (Paterina) labradorica swan- tonensis. Hall and Claj-ke [1892c, p. 98, fig. 54] Micromitra (Paterina) bella. The text includes both M. (P.) bella and M. (P.) labradorica swantonensis. Hall and Clarke [1892c, p. 98, PI. IV, figs. 8 and 9] Micromitra (Paterina) labradorica swan- tonensis. The text includes both M. (P.) labradorica swantonensis and M. (P.) bella. Oehlert [1887, p. 1270] Micromitra (Paterina) bella. Walcott [1886b, p. 100] Do. Walcott [1891a, p. 608] Do. i Iphidea bella? Grabau [1900, pp. 617-618] Do. Iphidea crenistria Walcott [1897b, p. 713] Micromitra (Paterina) crenistria. Iphidea labradorica Billings [1872b, p . 478] Micromitra (Paterina) labradorica. Billings [1874, p. 76] Do. Schuchert [1897, p. 234] Micromitra (Paterina) labradorica (in part) and M. (P.) labradorica swantonensis (in part). Iphidea labradorica swantonensis Schuchert [1897, p. 234]. Micromitra (Paterina) labradorica swan- tonensis. Iphidea logani Walcott [1897b, pp. 711-712] Micromitra (Paterina) logani. Iphidea ornatella Gronwall [1902, p. 40] Micromitra (Iphidella) ornatella. Hall and Clarke [1892c, pp. 97-98] Do. Linnarsson [1876, pp. 25-26] Do. Iphidea cnf.? ornatella Hall and Clarke [1892c, PI. IV, figs. 6 and 7] Micromitra (Paterina) superba. Iphidea pannula Matthew [1902c, p . 110] Micromitra (Iphidella) pannula. Iphidea pannulus Grabau and Shimer [1907, p. 201] Do. Schuchert [1897, p. 234] Do. Iphidea pealei Walcott [1897b, pp. 712-713] Micromitra pealei. Iphidea prospectensis Schuchert [1897, p . 234] Micromitra (Paterina) prospectensis. Iphidea (??) sculptilis Meek [1873, p. 479] Micromitra sculptilis. Iphidea sculptilis Schuchert [1897, p. 235] Do. Walcott [1899, pp. 447-448] Do. Iphidea stissingensis Schuchert [1897, p. 234] Micromitra (Paterina) stissingensis. Iphidea superba Walcott [1897b, p. 711] Micromitra (Paterina) superba. Iphidea swantonensis Grabau and Shimer [1907, p. 201] Micromitra (Paterina) labradorica swan- tonensis. Iphidea sp. undet. Walcott [1899, p. 449] Micromitra sp. undt. Iphidella Walcott [1905a, p. 304] Micromitra (in part), M. (Paterina) (in part), and M. (Iphidella) (in part). (Iphidella) [Micromitra], Walcott [1908e, PI. XI, and pp. 142 and 143]. ... Micromitra (Iphidella). Iphidella labradorica Walcott [1905a, p. 307] Micromitra (Paterina) labradorica. Iphidella labradorica orientalis Walcott [1905a, pp. 305-306] Micromitra (Paterina) labradorica orien- talis. Iphidella labradorica swantonensis Walcott [1905a, p. 307] Micromitra (Paterina) labradorica swan- tonensis. Iphidella labradorica utahensis Walcott [1905a, p. 306] Micromitra (Paterina) labradorica utahensis. (Iphidella) louise [Micromitra], Walcott [1908d, pp. 56-57] Micromitra (Iphidella) louise. IphidellamaiorWalcott[1905a, p. 304] Micromitra (Paterina) major (in part) and M. (P.) williardi (in part). Iphidella nisus Walcott [1905a, p . 305] Micromitra nisus. SYNONYiVnC EEFERENCES. 51 Present reference. (Iphidella) nyssa [Micromitra], Walcott [1908d, p. 57] Micromitra (Iphidella) 'lyssa. Iphidella paanula Walcott [1905a, p. 307] Micromitra (Iphidella) pannula. (Iphidella) pannula [Micromitra], Walcott [1908c, p. 244, PI. I, figs. 1, la-c] . . Do. Iphidella pannula maladensis Walcott [1905a, p . 306] Micromitra (Iphidella) pannula maladensia. Iphidella pannula ophirensis Walcott [1905a, p. 306] Micromitra (Iphidella) pannula ophirensis. Iphidella prospectensis Walcott [1905a, p. 307] Micromitra (Paterina) prospectensis. Iphidella sculptilis Walcott [1905a, p. 308] Micromitra sculptilis. Iphidella stissingensis Walcott [1905a, p. 308] Micromitra (Paterina) stissingensis. Iphidella sp. undt. Walcott [1905a, p. 305] Micromitra sp. undt. iphis [Obolus (Westonia)], Walcott [1905a, p. 336] Obolus (Westonia) iphis. irene [Lingula], Billings [1862d, pp. 71-72] Lingulella Irene. Billings [1863, p. 230] Do. il-ene [Lingulella], Schuchert [1897, p. 257] Do. iris [Lingula], Billings [1865a, p. 301] Lingulella iris. ismene [Obolus], Walcott [1905a, p. 325] Obolus ismene. isse [Obolus (Lingulella)], Walcott [1905a, p. 330] Lingulella isse. J. (JameseUa) [NisiLsia], Walcott [1905a, p. 252] Nisusia (JameseUa). Walcott [1908e, PL XI, and pp. 142 and 147] Do. (JameseUa) amii [Nisusia], Walcott [1905a, p. 2.52] Nisusia (JameseUa) amii. (JameseUa) argenta [Nisusia], Walcott [1905a, p. 2.52] Nisusia (JameseUa) argenta. (JameseUa) erecta [Nisusia], Walcott [1905a, p. 253] Nisusia (JameseUa) erecta. (JameseUa?) kanabensis [Nisusia?], Walcott [1908d, pp. 97-98] Nisusia? (JameseUa?) kanabensis. (JameseUa) kuthani [Nisusia], Walcott [1905a, pp. 253-254] Nisusia (JameseUa) kuthani. (JameseUa) lowi [Nisusia] , Walcott [1908d , p . 98] Nisusia (JameseUa) lowi . (JameseUa) perpasta [Nisusia], Walcott [1905a, pp. 254-255] Nisusia (JameseUa) perpasta. (JameseUa) perpasta macra [Nisusia], Walcott [1905a, p. 255] Nisusia (JameseUa) perpasta macra. (JameseUa) perpasta subquadrata [Nisusia], Walcott [1905a, p. 255] Nisusia (JameseUa) perpasta subquadrata. (JameseUa) utahensis [Nisusia], Walcott [1905a, pp. 255-256] Nisusia (JameseUa) utahensis. (JameseUa) sp. undt. [Nisusia], Walcott [1905a, p. 256] Nisusia (JameseUa) sp. iindt. jeremejewi [Helmersenia], Dall [1877, p. 31] Helmereenia ladogensis. Oehlert [1887, p. 1264] Do. johannensis [Orthis (Plectorthis)], Walcott [1905a, pp. 265-266] Eoorthis johannensis. johaimensis [Orthisina (?)], Matthew [1892, pp. 49-50] Do. K. kanabensis [Nisiisia? (JameseUa?)], Walcott [1908d, pp. 97-98] Nisusia? (JameseUa?) kanabensis. kayseri [Orthis (Plectorthis)], Walcott [1905a, p. 266] Eoorthis kayseri. kempanum [Protosiphon], Matthew [1897a, pp. 70-71] Trematobolus kempanum. Matthew [1898a, p. 131] Do. KeyserUngia Dall [1877, p. 39] Keyserlingia. HaUand Clarke [1892c, pp. 117-119] Do. Karpinsky [1887, p. 476] Helmersenia, not Keyserlingia. Oehlert [1887, p. 1263] Keyserlingia. Pander [1861, p. 46] Do. Walcott [1908e, PL XI, and pp. 142 and 146] Do. Keyserlingia buchi Hall and Clarke [1892c, p. 118] Keyserlingia buchi. Pander [1861, columns 46-48] Do. Keyserlingia panderi Karpinsky [1887, p. 476] Helmersenia ladogensis. kichouensis [Orthis (Plectorthis)], Walcott [1906, p. 570] Eoorthis kichouensis. kiurensis [Lingula?], Waagen [1885a, pp. 768-769] Lingulella kiurensis. Waagen [1891, PL II, figs. 17a-b] Do. kuthani [Nisusia (JameseUa)], Walcott [1905a, pp. 253-254] Nisusia (JameseUa) kuthani. kuthani [Orthis], Pompeckj [1896b, pp. 514-515] Do. kutorgai [Acrotreta], Walcott [1902, pp. 589-590] Acrotreta kutorgai (in part) and A. rudis (in part). Kutorgina Beecher [1891, pp. 345-346] Kutorgina. Billings [1861b, p. 9] Do. Billings [1861c, p. 948] Do. Billings [1862e, p. 220] Do. DaU [1877, pp. 40-41] Micromitra (Paterina) (in part) and Kutor- gina (in part). 52 CAMBRIAN BRACHIOPODA. Present reference. Kutorgina Davidson [1868, p. 312] Kutorgina. Davidson [1871, p. 342] Do. Grabau and Shinier [1907, p. 209] Do. Hall and Clarke [1892a, pp. 247-248] Do. Hall and Clarke [1892b, pp. 563-564] Do. Hall and Clarke [1892c, pp. 90-94, and 183] Micromitra (in part), Micromitra (Paterina) (in part), Micromitra (Iphidella) (in part), Kutorgina (in part), Protorthis (in part), and Billingsella (in part). OeUert [1887, p. 1262] Kutorgina. Walcott [1886b, pp. 101-102] Kutorgina (in part), Micromitra (in part), Micromitra (Paterina) (in part), and Micromitra (Iphidella) (in part). Walcott [1905a, pp. 306-308] Kutorgina. Walcott [19086, PI. XI, and pp. 142 and 145] Do. Zittel [1880, p. 664] Do. (Kutorgina) [Obolella], Dall [1870, pp. 154 and 163] Do. Kutorgina alata? Moberg [1892b, p. 113] Belongs with an undetermined genus. Kutorgina cingulata Beecher [1891, pp. 345-346] Kutorgina cingulata. Bornemann [1891, p. 440] Kutorgina sardiniaensis. Davidson [1868, p. 312] Micromitra (Paterina) phillipsi. Davidson [1871, pp. 342-343] Do. Davidson [1883, p. 212] Do. | Freeh [1897, PL lA, figs. 6a-b] Kutorgina cingulata. Grabau and Shimer [1907, p. 209] Do. Hall and Clarke [1892a, PL IV, figs. 11-13] Do. Hall and Clarke [1892c, p. 92] Do. von Toll [1899, pp. 26-27] Do. Walcott [1886b, pp. 102-104] Micromitra pusUla (in part), Micromitra (Paterina) phillipsi (in part), and Kutor- gina cingulata (in part). Walcott [1886b, pp. 102-104, PL IX, figs. 1, la-f] Kutorgina cingulata. Walcott [1886b, p. 103, PL IX, figs. Ig-h] Rustella edsoni. Walcott [1891a, p. 609, PL LXIX, figs. 1, la-f] Kutorgina cingulata. Walcott [1891a, p. 609, PL LXIX, figs. Ig-h] Rustella edsoni. Walcott [1905a, pp. 308-309] Kutorgina cingulata. (Kutorgina) cingulata [Obolella], Billings [1861b, pp. 8-9, figs. 8 and 10].. Do. Billings [1861b, p. 8, fig. 9] Rustella edsoni. Billings [1861c, p. 948, figs. 347 and 349].. Kutorgina cingulata. Billings [1861c, p. 948, fig. 348] Rustella edsoni. Billings [1862e, p. 220, figs. 347 and 349] . . Kutorgina cingulata. Billings [1862e, p. 220, fig. 348] Rustella edsoni. Kutorgina cingulata phillipsi Matley [1902, pp. 145-147] Micromitra (Paterina) phillipsi. Kutorgina cingulata pusilla Gronwall [1902, pp. 40-41] Micromitra pusUla. Linnarsson [1876, p. 25] - Do. Matley [1902, pp. 146-147] Do. Kutorgina granulata Matthew [1899a, p. 189] Kutorgina gxanulata. Matthew [1899e, p. 98] Do. Kutorgina labradorica Walcott [1886b, p. 104] Micromitra (Paterina) labradorica. The figures accompanying this reference [PL IX, figs. 2, 2a-b] represent M. (P.) labradorica swantonensis. Walcott [1886b, PL IX, figs. 2, 2a-b] Micromitra (Paterina) labradorica swan- tonensis. The text reference [p. 104] refers only to M. (P.) labradorica. Walcott [1891a, p. 609] Micromitra (Paterina) labradorica. Kutorgina labradorica swantonensis Walcott [1890b, p. 36] Micromitra (Paterina) labradorica swan- tonensis. Walcott [1891a, p. 609] Do. Kutorgina latourensis Hall and Clarke [1892c, pp. 93, 95, and 233] Protorthis latourensis. Matthew [1886, pp. 42-43] Do. Kutorgina minutissima Hall and Whitfield [1877, pp. 207-208] Micromitra sculptilis. SYNONYlVnC REFERENCES. 53 Present reference. Kutorgina paimula Pack [1906, p. 296] Micromitra (Iphidella) pannula. Walcott [1886b, p. 105] Do. Walcott [1887, p. 190] Do. Walcott [1891a, p. 609] Do. Kutorgina perugata Walcott [1 905a, p .• 310] Kutorgina perugata. Kutorgina prospectensis Walcott [1884b, p. 19] Micromitra (Paterina) prospectensis. Walcott [1886b, pp. 106-107] Do. Walcott [1891a, p. 610] Do. Kutorgina sardiniaensis Walcott [1901, p. 695] Kutorgina sardiniaensis. Walcott [1905a, p. 311] Do. Kutorgina sculptilis Walcott [1884b, p. 20] Micromitra sculptilis. Kutorgina stissingensis Dwight [1889, pp. 145-147] Micromitra (Paterina) etissingensis. Dwight [1891, p. 105] Do. Kutorgina undosa Moberg [1892b, p. 112] Micromitra (Paterina) undosa. Kutorgina whitfieldi Walcott [1884b, pp. 18-19] Billingsella whitfieldi. Kutorgina sp. Moberg [1892b, p. 114] Micromitra? sp. (See p. 357.) Kutorgina sp. undt. Walcott [1905a, p. 311] Kutorgina sp. undt. I. labiosa [Discina], Salter [1866a, p . 285] Acrotreta sagittalis. labradorica [Iphidea], Billings [1872b, p. 478] Micromitra (Paterina) labradorica. Billings [1874, p. 76] Do. Schuchert [1897, p. 234] Micromitra (Paterina) labradorica (in part) and M. (P.) labradorica swantonensis (in part). labradorica [Iphidella], Walcott [1905a, p. 307] Micromitra (Paterina) labradorica. labradorica [Kutorgina], Walcott [1886b, p. 104] Micromitra (Paterina) labradorica. The figures accompanying this reference [PI. IX, figs. 2, 2a-b] represent M. (P.) labradorica swantonensis. Walcott [1886b, PI. IX, figs. 2, 2a-b] Micromitra (Paterina) labradorica swanton- ensis. The text reference [p. 104] refers only to M. (P.) labradorica. Walcott [1891a, p. 609] Micromitra (Paterina) labradorica, labradorica [Paterina], Beecher [1891, pp. 345-346] Micromitra (Paterina) labradorica swanton- ensis. Hall and Clarke [1892a, p. 247] Do. labradorica orientalis [Iphidella], Walcott [1905a, pp. 305-306] Micromitra (Paterina) labradorica orien- talis. labradorica swantonensis [Iphidea], Schuchert [1897, p. 234] Micromitra (Paterina) labradorica swanton- ensis. labradorica swantonensis [Iphidella], Walcott [1905a, p. 307] Do. labradorica swantonensis [Kutorgina], Walcott [1890b, p. 36] Do. Walcott [1891a, p. 609] Do. labradorica utahensis [Iphidella], Walcott [1905a, p . 306] Micromitra (Paterina) labradorica utah- ensis. labradorica var. undt. [Micromitra (Paterina)], Walcott [new] Micromitra (Paterina) labradorica var. undt. labradoricus [Obolus], Billings [1861b, p. 6] Micromitra (Paterina) labradorica. Billings [1861c, p. 946] Do. Billings [1862e, p. 218] .".. Do. Billings [1863, p, 284] Do, ladogensis [Siphonotreta], Jeremejew [1856, pp. 73 and 80] Helmersenia ladogensis. Isevis [Acrothele subsidua], Walcott [new] Acrothele subsidua Isevia. Isevis [Lingulella], Matthew [1892, p. 39] Lingulella Isevis. tevis [Protorthis], Walcott [1905a, p. 283] Protorthis Isevis. Isevis grandis [Lingulella], Matthew [1903, pp. 200-201] Lingulella tevis grandis. Ijevis lens [Lingulella], Matthew [1903, pp. 201-203] Lingulella lens. Iseviusculus [Orthis (Plectorthis) wichitaensis], Walcott [1905a, p. 272] Eoorthis wichitaensis Iseviusculus. Iseviusculus [Syntrophia texana], Walcott [1905a, pp. 294-295] Huenella texana Iseviusculus. Lakhmina Hall and Clarke [1892a, pp. 234-235] Neobolus. Hall and Clarke [1892b, pp. 550-551] Do. Halland Clarke [1892c, pp. 28-30] Do. Oehlert [1887, p. 1265] Do. ' Waagen [1891, desc. o£ PI. II, figs. 3 and 4] Do. 54 CAMBEIAN BRACHIOPODA. Present reference. Lakhmina linguloides Freeh [1897, PI. lA, figs. 4a-b] Neobolus warthi. Hall and Clarke [1892a, p. 234] Do. Hall and Clarke [1892b, p. 550] Do. Hall and Clarke [1892c, p. 28] Do. Oehlert [1887, p. 1265] Do. Waagen [1891, desc. of PI. II, figs. 3 and 4] Do. lamborni [Lingulella], Keyes [1894, pp. 38-39] Obolus lambomi. lamborni [Lingulella?], Meek [1871, pp. 185-187] Do. lamborni minimus [Obolus (Lingulella)], Walcott [1898b, p. 407] Obolus lambomi minimus. lamellosa [Lingula], Barrande [1879b, PI. CVI, figs, i: 1-5; PI. CXI, figs, ix: 1-3] Obolus (Westonia?) lamellosus. lamellosus [Obolus (Westonia?)], Walcott [1901, p. 691] Do. lata [Acrothele matthewi], Hall and Clarke [1892a, PI. Ill, figs. 25 and 26] . . Acrothele matthewi lata. Hall and Clarke [1892c, PI. Ill, figs. 26-28] Do. Matthew [1886, p. 41] Do. Matthew [1895a, PI. V, figs. 8a-b] Do. Matthew [1903, p. 104] Do. lata [Acrotreta papillata], Matthew [1903, pp. 95-96] Acrothyra sera. lateralis [Syntrophia], Hall and Clarke [1892c, p. 270] Syntrophia lateralis. Hall and Clarke [1893b, p. 217] Do. Hall [1894a, p. 837] Do. lateralis [Triplesia], Whitfield [1886, p. 303] Do. latourensis [Kutorgina], Hall and Clarke [1892c, pp. 93, 95, and 233] Protorthis latourensis. Matthew [1886, pp. 42-43] Do. latourensis [Protorthis], Walcott [1905a, pp. 282-283] Do. latus [Obolus (Schmidtia) obtusus], Mickwitz [1896, pp. 174-175] Obolus (Schmidtia) obtusus. leda [Obolus tetonensis], Walcott [1908d, p. 63] Obolus tetonensis leda. lens [Lingula?], Matthew [1901a, pp. 274-275] Lingulella lens. lens [Lingulella], Matthew [1903, pp. 205-206] Do. lens [Lingulella tevis], Matthew [1903, pp. 201-203] Do. lens [Obolus], Matthew [1902c, p. 95] Obolus (Palseobolus) bretonensis lens. lens [Obolus (Lingulella)], Walcott [1902, pp. 606-607] Lingulella lens. lens [Obolus (Pateobolus)], Matthew [1903, pp. 144-146] Obolus (Pateobolus) bretonensis lens. lens longus [Obolus (Palseobolus)], Matthew [1903, pp. 146-147] Do. lens-primus [Obolus], Matthew [1902c, pp. 94-95] Do. lenticularis [Anomites], Wahlenberg [1821, pp. 66-67] Omsia lenticularis. lenticularis [Atrypa?], Dalman [1828, pp. 132-133] Do. Hisinger [1837, p. 76] Do. lenticularis [Atrypa], Kjerulf [1857, p. 92] Do, Kjerulf [1865, pp. 1 and 3] Do. Kjerulf [1879, PL XIII] Do. lenticularis [Orthis], Brogger [1882, p. 48] Do. Davidson [1868, p. 314] Do. Davidson [1869, pp. 230-232] Do. Matthew [1892, pp. 46^8] Do. Matthew [1903, pp. 213-216] Do. Roemer [1876, PI. II, figa. 4a-c] Do. Roemer [1885, pp. 33-34] Do. Salter [1866b, p. 339] Do. Salter and Etheridge [1881, pp. 544-545] Do. lenticularis? [Orthis], Kayser [1876, p. 9] Do. lenticularis [Orthis (Orusia)], Walcott [1905a, pp. 273-276] Do. lenticularis [Spirifera?], von Buch [1834, p. 48] Do. lenticularis atrypoides [Orthis], Matthew [1892, p. 48] Orusia lenticularis atrypoides. Matthew [1903, p. 217] Do. lenticularis atrypoides [Orthis (Orusia)], Walcott [1905a, p. 276] Do. lenticularis lyncioides [Orthis], Matthew [1892, p. 49] Orusia lenticularis lyncioides. Matthew [1903, p. 216] Do. lenticularis lyncioides [Orthis (Orusia)], Walcott [1905a, p. 277] Do. lenticularis etrophomenoides [Orthis], Matthew [1892, p. 49] Orusia lenticularis. Matthew [1903, p. 217] Do. leos [Obolus (Lingulella)], Walcott [1898b, pp. 407-408] Lingulella leos. lepis [Lingula?], Davidson [1866, p. 54] Lingulella lepis. SYNONYMIC REFERENCES. 55 Present reference. lepis [Lingula], Salter [1859, p. 543] Lingulella lepis. lepis [Lingula (Lingulella?)], Brogger [1882, p. 44] Do. lepis [Lingula (Lingulella)], Davidson [1866, desc. of PI. Ill] Do. lepis [Lingulella], Davidson [1868, pp. 307-308] Do. Davidson [1871, PI. XLIX, figs. 31 and 31a] Do. Holm [1898, p. 148] Do. Moberg and Segerberg [1906, pp. 62-63] Do. Salter [lS66b, p. 334] Do. Salter and Etheridge [1881, p. 538] Do. lepis [Lingulella cf.], Matthew [1903, p. 204] Do. lepia? [Lingulella], Weatergard [1909, p. 57] Do. Wiman[1902, pp. 66 and 71] Do. Lepteena barabuensis Whitfield [1878, p. 60] Syntrophia barabuensis. WTiitfield [1882, pp. 171-172 and 195] Do. Leptsena melita Hall and "WTiitfield [1877, p. 208] Variety of Eoorthis desmopleura. (Leptembolon) [Obolus], Mickwitz [1896, p. 199] Lingulella (Leptembolon) . Walcott [1908e, PL XI, and pp. 142 and 144]. . . . Do. (Leptembolon) lingulseformis [Obolus], Mickwitz [1896, pp. 200-204] Lingulella (Leptembolon) lingulseformis. (Leptembolon) lingulseformis solidus [Obolus], Mickwitz [1896, pp. 204-205] Do. Leptobolus Matthew [1903, pp. 105-106] Lingulella. Leptobolus atavus Matthew [1899b, pp. 200-201] Lingulella atava. Matthew [1903, pp. 106-109] Do. Leptobolus atavus insulae Matthew [1903, pp. 110-112] Lingulella atava insulse. Leptobolus atavus tritavus Matthew [1903, p . 109] Lingulella torrentis. Leptobolus? coUicia Matthew [1899b, p . 200] Lingulella coUicia. Leptobolus collicia Matthew [1903, pp. 112-113] Do. Leptobolus coUicia collis Matthew [1903, pp. 114-115] Do. Leptobolus flumenis Matthew [1903, pp. 189-190] Lingulella flumenis. Leptoboluci gemmulus Matthew [1903, pp . 190-192] Lingulella ferruginea. Leptobolus grandis Matthew [1894, pp. 91-92] Lingulella grandis. Leptobolus ct. grandis Matthew [1902c, p. Ill] Does not equal Lingulella grandis. It is not referred in this monograph. Leptobolus linguloides Matthew [1902b, p. 407] Lingulella ferruginea. Matthew [1903, p. 193] Do. Leptobolus cf. linguloides Matthew [1902b, p. 407] Do. Matthew [1903, pp. 192-193] Do. Leptobolus torrentis Matthew [1903, pp. 74-75] ,. Lingulella torrentis. lesleyi [Huenella], Walcott [1908d, p. 110] Huenella lesleyi. levisensis [Acrothele], Walcott [1908d, p. 85] Acrothele levisensia. Hani [Acrotreta], Walcott [1905a, p. 300] Acrotreta lisani. limoensia [Acrotreta], Wiman [1902, p. 54] Acrotreta uplandica limoensis. limonensis [Acrotreta uplandica], Walcott [1905a, p. 303] Do. lindstromi [Billingsella], Walcott [1905a, pp. 238-239] Billingsella lindstromi. lindstromi [Obolella], Walcott [1901, pp. 674-675] Obolella? lindstromi. lindstromi [Orthis], Linnarason [1876, pp. 10-12] Billingsella lindstromi. lineolatus [Obolus (Lingulella)], Walcntt [1898b, pp. 408-409] Lingulella lineolata. Lingula acuminata Billings [1863, p. 102] Lingulella (Lingulepis) acuminata. Chapman [1863, p. 187] Do. Chapman [1864, p. 159] Do. Conrad [1839, p. 64] Do. Emmons [1855, p. 203] Do. Hall [1847, p. 9] Do. Lingula acutangula Roemer [1849, p. 420] Lingulella acutangula. Roemer[1852, p. 90] Do. Lingula agnostorum Wallerius [1895, pp. 64-65] Lingulella agnostorum. Lingula ampla Hall [1863, p. 125] Lingulella ampla. Hall [1867, pp. 101-102] Do. Owen [1852, p. 583] Do. Lingula ancilla Barrande [1879b, PI. 0X1, fig. vi] Obolus? ancillus. Lingula antiqua Billings [1856, p . 34] Lingulella (Lingulepis) acuminata. Emmona[1842, p. 268] Do. Emmons [1863, p. 92] Do. Hall [1847, pp. 3^] Do. 56 CAIMBRIAN BRACHIOPODA. Present reference. Lingula antiqua Hall [1851, pp. 204-205] Lingulella (Lingulepis) acuminata. Han[lS62, fig. 2, p. 21] ' Do. Hayden [1862, p. 73] Do. James [1895, p. 884] Do. Owen [1851, p. 170] Do. Rogers [1861, p. 390] Obolus (Westonia) rogersi. Lingula antiquata Emmons [1855, pp. 202-203] Lingulella (Lingulepis) acuminata. Lingula attenuata Bornemann [1891, pp. 437-438] Lingulella bornemanni. Lingula aurora Hall [1861, p. 24] Obolus (Westonia) aurora. Hall [1862, p. 21] Do. Hall [1863, pp. 126-127] Do. Hall[1867, pp. 103-104] Do. Sardeson [1896, p. 95] Do. Lingula aurora var. Hall [1863, pp. 127-128] Obolus (Westonia) stoneanus. Hall [1867, pp. 104-106] Do. Lingula bavarica Barrande [1868a, p. 100] Obolus? bavaricus. Barrande [1868b, pp. 690-691] Do. Lingula belli Billings [1859, pp. 431^32] Obolus belli. Billings [1863. figs. 47a-b, p. 124] Do. Lingula billingsana Matthew [1903, p. 205] Lingulella bellula. Lingula billingsiana WTiiteaves [1878, p. 226] Lingulella billingsiana. Lingula cf . billingsiana Matthew [1894, p. 93] Lingulella grandis. Lingula bottnica Wiman [1902, p. 51] Obolus (Westonia) bottnicus. Lingula? bryograptorum Moberg and Segerberg [1906, p. 63] Lingulella lepis. Westerg&rd [1909, p. 57] Do. Lingula cedens Barrande [1868a, p. 102] Lingulella cedens. Barrande [1868b, pp. 691-692] Do. Lingula? corrugata Moberg and Segerberg [1906, p. 63] Lingulella lepis. Westerg&rd [1909, p. 57] Do. Lingula cyane Billings [1865a, p. 216] Obolus cyane. Lingula dakotensis Meek and Hayden [1865, p. 3] Lingulella (Lingulepis) acuminata. Whitfield [1880, pp. 337-338] Do. Lingula davidsoni Barrande [1879b, PI. CIV, figs, viii: 1^] Lingulella davidsoni. Lingula davisi McCoy [1851b, pp. 405-406] Lingulella davisi. McCoy [1854, p. 252] Do. Lingula cf. davisi Schmidt [1881, p. 17, fig. 5] Obolus (Mickwitzella) siluricus. Lingula? dawsoni Matthew MS. [1884] Lingulella ferruginea. Walcott [1884a, p. 15] Do. Lingula dolata Sardeson [1896, p. 95] Obolus dolatus. Lingula aff . exungui Gtirich [1896, p. 214] Lingulella siemii-adzkii. Lingula cf. exunguis Giirich [1892, p. 69] Do. Siemiradzki [1886, p. 672] Do. • Lingula (?) favosa Linnarsson [1869a, pp. 356-357]. Obolella (Glyptias) favosa. Linnarsson [1869b, p. 406] Do. Lingula feistmanteli Barrande [1879b, Pis. CVI and CX] Obolus feistmanteli. Lingula hawkei Roualt Not taken up in this monograph ; it does not equal Mickwitzia sp. undt. Lingula hawkei? Bornemann [1891, p. 439] Mickwitzia sp. undt. Lingula humillima Barrande [1868a, p. 101] Lingulella? humillima. Barrande [1868b, p. 691] Do. Lingula inchoans Barrande [1868a, p. 102] Acrotreta inchoans. Barrande [1868b, p. 692] Do. Lingula insons Barrande [1879b, PI. CV, figs, x: 1-6] Lingulella? insons. Lingula iole Billings [1865a, p. 215] Lingulella iole. Lingula Irene Billings [1862d, pp. 71-72] Lingulella irene. Billings [1863, p. 230] Do. Lingula iris Billings [1865a, p. 301] Lingulella iris. Lingula? kiurensis Waagen [1885a, pp. 768-769] Lingulella kiurensis. Waagen [1891, PL II, figs. 17a-b] Do. Lingula lamellosa Barrande [1879b, PI. CVI, figs, i: 1-5; PI. CXI, figs. IX : 1-3] Obolus (Westonia?) lamellosus. Lingula? lens Matthew [1901a, pp. 274-275] Lingulella lens. Lingula? lepis Davidson [1866, p. 54] Lingulella lepis. Lingula lepis Salter [1859, p. 543] Do. SYNONYMIC REFEEENCES. 57 Present reference. Lingula? manticula Walcott [1884b, pp. 13-14] Lingulella punctata. WTiite [1874, pp. 9-10] Lingulella arguta (in part) and L. manti- cula (in part). WTiite [1877, pp. 52-53, PI. Ill, fig. 2a] Lingulella arguta. The text also includes L. manticula. WTiite [1877, p. 52, PI. Ill, fig. 2b] Lingulella manticula. The text includes L. arguta. Lingula matthewi Hartt [1868, p. 644] Acrothele matthewi. Hartt [1878, p. 644] Do. Hartt [1891, p. 644] Do. Lingula? miranda Barrande [1879b, PI. CXI] Obolus? mirandus. Lingula? monilifera Linnarsson [1869a, p. 344] Mickwitzia monilifera. Lingula monilifera Linnarsson [1869b, p. 398] Do. Lingula mosia Hall [1863, p. 126] Lingulella mosia. Hall [1867, pp. 102-103] Do. Sardeson [1896, p. 95] Do. Lingula? ordovicensis Moberg and Segerberg [1906, p. 63] Lingulella lepis. Lingula ovata Emmons [1842, p. 105] Lingulella prima. McCoy [1846. p. 24] Lingula ovata, not Lingulella davisi. McCoy [1854. p. 254] Lingulella davisi (in part) and Lingula ovata (in part). Lingula petalon Bomemann [1891, p. 438] Obolus? meneghinii. Davidson [1868, p. 308] Does not equal Obolus ? meneghinii. Davidson [1871, p. 337] - Does not equal Obolus ? meneghinii. Lingula pinnaformis Owen [1852, p. 583] Lingulella (Lingulepis) acuminata. Lingula pinnaeformis Hall [1862, p. 435, and fig. 3. p. 21] Do. Lingula polita Hall [1861, p. 24] Dicellomus politus. Lingula? polita Hall [1862, pp. 21 and 435] Do. Lingula polita WTiitfield [1862, p. 136] Do. Lingula prima Billings [1856, p. 34] Lingulella (Lingulepis) acuminata. Emmons [1855, p. 202] Lingulella prima. Hall [1847, p. 3] , Do. Hall [1851 , p. 204] Lingulella (Lingulepis) acuminata. Hayden [1862, p. 73] Probably equals Lingulella (Lingulepis) acuminata. Owen [1851, p. 170] Lingulella (Lingulepis) acuminata. Rogers [1861, p. 390] Obolus (Westonia) rogersi. Lingula? produrta Moberg and Segerberg [1906, p. 63] I/ingulella lepis. Lingula pygmsea Davidson [1866, p. 53] Lingulella (Lingulepis?) pygmaea. Matley [1902, p. 141] Do. Phillips [1871, p. 68] Do. Salter [1865, p. 102] Do. Lingula roualti Bornemann [1891, p. 439] Kutorgina sardiniaensis. Lingula? signata Barrande [1868a, p. 103] Lingulella signata. Barrande [1868b, p. 692] Do. Lingula simplex Barrande [1879b, PI. CIV, figs, vi: 1-4] Lingulella? simplex. ?Lingula squamosa Davidson [1866, p. 41] Lingulella (Lingulepis?) squamosa. Lingula squamosa Holl [1865, p. 102] Do. Lingula? warthi Waagen [1885a, pp. 769-770] Lingulella kiurensis. Waagen[1891, PL II, figs. 18a-b] Do. Lingula winona Hall [1863, p. 126] Lingulella winona. Hall [1867, p. 102] Do. Sardeson [1896. p. 96] Do. Lingula wirthi Barrande [1868a, p. 101] Lingulella wirthi. Barrande [1868b, p. 691] Do. Lingula sp. Davis [1846, p. 70] Lingulella davisi. Sedgwick[1847,pp. 140, 143, andl47] Do. Lingula? sp. No. 1 Wiman [1902, p. 51] Obolus (Westonia) wimani. No. 2 Wiman [1902, p. 52] Obolus (Westonia) alandensis. Lingula or Lingulella sp. Linnarsson [1876, pp. 15-16] Doubtfully equals Lingulella ferruginea. Lingula (Glossina) acuminataHall and Clarke [1892c, PL I, figs. 1 and 2].. Lingulella (Lingulepis) acuminata sequens. 58 CAMBKIAN BRACHIOPODA. Present reference. Lmgula (Lingulella) Oehlert, [1887, p. 1261] Lingulella. Lingula (Lingulella?) lepis Brogger [1882, p. 44] Lingulella lepis. Liugula (Lingulella) lepis Davidson [1866, desc. of PI. Ill] Do. Lingula (Lingulepis) Oehlert [1887, p. 1261] Lingulella (Lingulepis). lingula-comes [Tellinomya], McCoy [1851a, p. 56] Lingulella davisi. Salter Does not equal Lingulella davisi. lingulseformis [Obolus (Leptembolon)], Mickwitz [1896, pp. 200-204] Lingulella (Leptembolon) lingulasformis. lingulseformis soHdus [Obolus (Leptembolon)], Mickwitz [1896, pp. 204- 205] Do. Lingulella Bornemann [1891, pp. 435-437] Lingulella. Dall[1870, pp. 153 and 159] Do. Dall [1877, p. 44] Do. Davidson [1866, p. 55] Do. Davidson [1868, p. 304] Do. Delgado [1904, p. 367] Do. Grabauand Shimer [1907, p. 192] Obolus (Westonia). Hall and Clarke [1892a, pp. 232-233] Lingulella (in part) and Botsfordia (in part) Hall and Clarke [1892b, pp. 548-549] Lingulella. Hall and Clarke [1892c, pp. 55-59] Lingulella (in part), Botsfordia (in part), Obolus (Westonia) (in part), etc. Matthew [1899b, p. 201] Lingulella. Matthew [1902c, p. 103] Do. Matthew [1903, p. 116]... :.. Do. I Meek [1871, pp. 186-187] Do. Salter [1866b, p. 333] Do. Salter and Etheridge [1881, p. 537] Do. Walcott [1908e, PL XI, and pp. 142 and 144] Do. Zittel[1880, pp. 663-664] Do. (Lingulella) [Lingula], Oehlert [1887, p. 1261] Do. (Lingulella) [Obolus], Walcott [lS98b, pp. 390-392] Do. Walcott [1901, p. 683] .' Do. (Lingulella) acutangulus [Obolus], Walcott [1898b, pp. 393 and 394, Pis. XXVII and XXVIII] - Lingulella acutangula. Lingulella? afBnis Billings [1872b, p. 468] Obolus (Lingulobolus) affinis. Billings [1874, p. 67] Do. Lingulella affinis Billings [1882, pp. 15-16] Do. Lingulella ampla Schuchert [1897, p. 257]. . ., Lingulella ampla. (Lingulella) amplus [Obolus], Walcott [1898b, pp. 392 and 394, PI. XXVIII] Do. (Lingulella) argutus [Obolus] Walcott [1898b, p. 396] Lingulella arguta. (Lingulella) atavus [Obolus], Walcott [1902, pp. 609-610] Lingulella atava. (Lingulella) auga [Obolus] , Walcott [1898b , pp . 396-397] Lingulella auga. Lingulella aurora Grabau and Shimer [1907 , p . 193] Obolus (Westonia) aurora. Hall [1873, pp. 244-245] Do. Hall and Clarke [1892c, PI. II, figs. 12 and 13] Do. Lingulella aurora var. Hall [1873, pp. 244-245] Obolus (Westonia) stoneanus. (Lingulella) bellulus [Obolus], Matthew [1903, p. 205] Lingulella bellula. Walcott [1898b, p. 398] Do. (Lingulella) bellus [Obolus], Matthew [1903, p. 204] Lmgulella bella. Walcott [1898b, pp. 397-398] Do. Walcott [1901, pp. 685-687] Lingulella bella (in part), L. concinna (in part), and L. lens (in part). (Lingulella) bicensis [Obolus], Walcott [1901, p. 688] Botsfordia cKlata. Lingulella? billingsana Schuchert [1897, p. 256] Lingulella grandis (in part) and L. billingsiana (in part). (Lingulella) bornemanni [Obolus], Walcott [1901, pp. 687-688] Lingulella bornemanni. Lingulella buttsi Walcott [190Sd, pp. 70-71] Lingulella buttsi. Lingulella cselata Ford [1878, pp. 127-128] Botsfordia cselata. Hall and Clarke [1892a, PI. Ill, figs. 1-4] Do. Hall and Clarke [1892c, pp. 57 and 58] Do. Walcott [1886b, p. 95] Do. Walcott [1887, p. 199, PI. I, fig. 16] Do. Walcott [1891a, p. 607] Do. (Lingulella) canius [Obolus], Walcott [1902, pp. 610-611] Lingulella cania. SYNONYMIC REFEEENCES. 59 Present reference. (Lingulella) celatus [Obolus], Walcott [1898b, PI. XXVI, figs. 1 and 2] ....Obolus (Schmidtia) celatus. (Lingulella) chinensis [Obolus], Walcott [1905a, pp. 328-329] Obolus chinensis. (Lingulella) chuarensis [Obolus], Walcott [1898b, p. 399] Obolus (Westonia) chuarensis. Lingulella clarkei Walcott [new] Lingulella clarkei. Lingulella? coelata Matthew [1895a, p. 126] Botsfordia cselata. (Lingulella) coUicia [Obolus], Walcott [1902, p. 610] Lingulella collicia. Lingulella concinna Matthew [1901a, pp. 273-274] Lingulella concinna. Matthew [1903, pp. 203-204] Do. (Lingulella) concinnus [Obolus], Walcott [1902, pp. 608-609] Do. Lingulella? cuneata Matthew [1894, pp. 92-93] Lingulella grandis. (Lingulella) cuneolus [Obolus], Walcott [1899, p. 443] Lingulella cuneola. (Lingulella) damesi [Obolus], Walcott [1905a, p. 329] Obolus damesi. (See Lingulella damesi, p. 489.) Lingulella davisi Davidson [1868, pp. 304 and 306] Lingulella davisi. Hall and Clarke [1892a, p. 232] Do. Hall and Clarke [1892b, p. 548] Do. Hall and Clarke [1892c, pp. 56 and 57] Do. Meek [1871, pp. 186-187] Do. Salter [1866b, pp. 333-334] Do. Lingulella davisii Davidson [1866. pp. 56 and 57] Do. Hall [1873, PI. XIII, fig. 4] Do. Roemer [1876, PL II, figs. 5a-c] Do. Salter [1867, pp. 44 and 52] Do. Salter and Etheridge [1881, pp . 537-538] Do . Lingulella cf. davisii Kayser [1897, p. 280] Do. Matthew [1902b, pp. 407^08] Do. Matthew [1903, p. 203] Do. (Lingulella) davisii [Obolus], Walcott [1898b, pp. 394 and 395] Do. Lingulella dawsoni Hall and Clarke [1892c, p. 58] Lingulella ferruginea. Matthew [1886, pp. 33-34, PI. V, figs. 9, 9a-c] Lingulella martinensis. The text includes L. ferruginea. Matthew [1886, pp. 33-34, PL V, fig. 9d] Lingulella ferruginea. The text includes I L. martinensis. Lingulella delgadoi Walcott [new] Lingulella delgadoi. (Lingulella) desideratus [Obolus], Walcott [1898b , pp . 399^00] Lingulella desiderata. Walcott [1899, pp. 445^46, PI. LX, fig. 2]. . Do. Walcott [1899, pp. 445-446, PI. LX, fig. 2a] Obolus rotundatus. (Lingulella) discoideus [Obolus], Walcott [1901, p. 673] Obolus discoideus. (Lingulella) dubius [Obolus], Walcott [1898b, p. 401] Lingulella dubia. Lingulella ella Had and Clarke [1892c, p. 58, figs. 19 and 21] Obolus (Westonia) ella. The text includes also specimens representing Lingulella dubia. Hall and Clarke [1892c, p. 58, fig. 20] Lingulella dubia. Pack [1906, p. 295] Obolus (Westonia) ella. Walcott [1886b, pp. 97-98, PI. VII, fig. 2; PL VIII, figs, 4, 4a, 4d-e] Obolus (Westonia) ella. The text includes also specimens representing Lingulella dubia. Walcott [1886b, pp. 97-98, PL VIII, figs. 4b-c] Lingulella dubia. The text includes Obo- lus (Westonia) ella. Walcott [1891a, p. 607, PL LXVII, figs. 2c-d] Lingulella dubia. The text includes Obolus (Westonia) ella. Walcott [1891a, p. 607, PL LXVII, figs. 2, 2a-b, and 2e] . . . .Obolus (Westonia) ella. The text includes also specimens representing Lingulella dubia. (Lingulella) ella [Obolus], Walcott [1898b, PI. XXVIII, figs. 5-8] Obolus (Westonia) ella. (Lingulella) ellsi [Obolus], Walcott [1898b, p. 402] Lingulella ellsi. Lingulella (?) escasoni Matthew [1901a, pp. 270-273] Obolus (Westonia) escasoni. (Lingulella) euglyphus [Obolus], Walcott [1898b, pp. 402^03] Obolus (Westonia) euglyphus. Lingulella ? cf. Lingula favosa Matthew [1888, pp. 28-29] Botsfordia pulchra. Lingulella ferruginea Davidson [1868, pp. 306-307] Lingulella ferruginea. 60 CAMBRIAN BRACHIOPODA. Present reference. Lingulella ferruginea Davidson [1871, pp. 336-337] Lingulella ferruginea. Davidson [1883, PI. XVII, fig. 35] Do. Delgado [1904, pp. 368-369] Lingulella delgadoi. Matthew [1903, p. 108] Lingulella ferruginea. Salter [Salter and Hicks, 1867, p. 340] Do. Salter and Etheridge [1881, p. 538] Do. Lingulella cf . ferruginea Kayser [1897, p. 280] Do. Lingulella ferruginea ovalis Davidson [1868, p. 307] Do. Hicks [Salter and Hicks, 1867, p. 341] Do. (Lingulella) fragilis [Obelus], Walcott [1898b, p. 404] Obolus fragilis. (Lingulella) franklinensis [Obolus], Walcott [1898b, pp. 404-405] Lingulella franklinensis, Lingulella fuchsi Redlich [1899, p. 7] Lingulella iuchsi. (Lingulella) fuchsi [Obolus], Walcott [1905a, p. 332] Do. (Lingulella) gemmulus [Obolus], Walcott [1901, p. 673] Lingulella ferruginea. Lingulella genei Pack [1906, p. 295] Lingulella dubia. Lingulella granvillensis Delgado [1904, pp. 367-368] Lingulella delgadoi. Hall and Clarke [1892c, p. 58] Lingulella granvillensis. Oehlert [1889, p. 1138] Do. Walcott [1887, pp. 188-189] Do. Walcott [1891a, pp. 607-608] Do. Lingulella cf. granvillensis Matthew [1895a, pp. 114-115] Lingulella martinensis. Lingulella gregwa Matthew [1899b, pp. 199-200] Lingulella (Lingulepis) gregwa. (Lingulella) hayesi [Obolus], Walcott [1898b, pp. 405-406] .Lingulella hayesi. Lingulella heberti Barrois [1882, pp. 185-186] Lingulella heberti. (Lingulella) helena [Obolus], Walcott [1898b, p. 406] Lingulella helena. Lingulella? iniiata Matthew [1886, p. 33] Acrotreta inflata. Matthew [1895a, p. 127] Do. Matthew [1898a, p. 128] Do. Lingulella? inflata ovalis Matthew [1895a, p. 127] Do. (Lingulella) ino [Obolus], Walcott [1898b, pp. 406-407] Lingulella ino. Lingulella irene Schuchert [1897, p. 257] Lingulella Irene. (Lingulella) isse [Obolus], Walcott [1905a, p. 330] Lingulella isse. Lingulella laevis Matthew [1892, p. 39] Lingulella Isevis. Lingulella Isevia grandis Matthew [1903, pp. 200-201] Lingulella Isevis grandis. Lingulella Isevis lens Matthew [1903, pp. 201-203] Lingulella lens. Lingulella lamborni Keyes [1894, pp. 38-39] Obolus lamborni. Lingulella? lamborni Meek [1871, pp. 185-187] Do. (Lingulella) lamborni minimus [Obolus], Walcott [1898b, p. 407] ..Obolus lamborni minimus. Lingulella lens Matthew [1903, pp. 205-206] Lingulella lens. (Lingulella) lens [Obolus], Walcott [1902, pp. 606-607] Do. (Lingulella) leos [Obolus], Walcott [1898b, pp. 407-408] Lingulella leos. Lingulella lepis Davidson [1868, pp. 307-308] Lingulella lepis. Davidson [1871, PL XLIX, figs. 31 and 31a] Do. Holm [1898, p. 148] Do. Moberg and Segerberg [1906, pp. 62-63] Do. Salter [1866b, p. 334] Do. Salter and Etheridge [1881, p. 538] Do. Lingulella lepis? Westergfird [1909, p. 57] Do. Wiman [1902, pp. 66 and 71] Do. Lingulella cf . lepis Matthew [1903, p. 204] Do. (Lingulella) lepis [Lingula], Davidson [1866, desc. of PI. Ill] Do. (Lingulella?) lepis [Lingula], Brogger [1882, p. 44] Do. (Lingulella) lineolatus [Obolus], Walcott [1898b, pp. 408^09] Lingulella lineolata. Lingulella linguloides Matthew [1886, p. 34] Lingulella feiTuginea. Lingulella cf. linguloides Delgado [1904, pp. 369-370] Lingulella delgadoi. (Lingulella) linnai'ssoni [Obolus], Walcott [1901, p. 688] Lingulella linnar.ssoni. Lingulella longovalis Matthew [1903, pp. 123-125] Lingulella triparilis. Lingulella mcconnelli Matthew [1902c, p. 108] Obolus mcconnelli. Walcott [1889c, p. 441] Do. Linguella? msera Hall and Clarke [1892c, p. 61] Obolus maera. Walcott [1897a, p. 404] Do. (Lingulella) mrera [Obolus], Walcott [1899, p . 443] Do. SYNONYMIC REFERENCES. 61 Present reference. Lingulella martinensis Matthew [1890, pp. 155-156] Lingulella martinensis. Matthew [lS95a, pp. 113-114] Do. Lingulella? matinalis Walcott [1897a, p. 404] Obolus matinalis. (Lingulella) matinalis [Obolus], Walcott [1899, p. 443] Do. Lingulella minuta Schuchert [1897, p. 257] Linnarssonella minuta. (Lingulella) mosia osceola [Obolus], Walcott [1898b, p. 409] Lingulella mosia osceola. (Lingulella) nanno [Obolus], Walcott [1898b, p. 409] Lingulella nanno. Lingulella? nathorsti Linnarsson [1876, pp. 15-16] Lingulella nathorsti. Lingulella nicholsoni Callaway [1874, p. 196] Lingulella nicholsoni. Callaway [1877, pp. 668-669] Do. Davidson [1883, pp. 208-209] Do. Lingulella nicholsoni? Matley [1902, p. 141] Do. (Lingulella) orus [Obolus], Walcott [190.5a, p. 330] Lingulella ora. (Lingulella) oweni [Obolus], Walcott [1898b, p. 410] Lingulella oweni. {Lingulella) pelias [Obolus], Walcott [1905a, pp. 330-331] Obolus mcconnelli pelias. (Lingulella) perattenuatus [Obolus], Walcott [1899, p. 443] Lingulella perattenuata. (Lingulella) phaon [Obolus], Walcott [1898b, pp. 410-411] Lingulella phaon. (Lingulella) pogonipensis [Obolus], Walcott [1898b, pp. 411^12] Lingulella pogonipensis. Lingulella? prima Hall and Clai-ke [1892c, p. 69] Lingulella prima. Lingulella primseva Davidson [1883, p. 208] Lingulella? primseva. Hicks [1871, p. 401] Do. Hicks [1881, p. 297] Do. Salter and Etheridge [1881, p. 538] Do. (Lingulella) prindlei [Obolus], Walcott [1898b, p. 412] Obolus prindlei. (Lingulella) punctatus [Obolus], Walcott [1898b, pp. 412^13]. Lingulella punctata. (Lingulella) quadrilateralis [Obolus], Walcott [1905a, p. 331] Lingulella quadrilateralia. Lingulella radula Matthew [1891, pp. 147-148] Lingulella radula. Lingulella radula aspera Matthew [1903, pp. 204-205] Do. (Lingulella) randomensis [Obolus], Walcott [1901, pp. 688-689] Lingulella randomensis. Lingulella roberti Matthew [1895b, pp. 256-257] Lingulella (Lingulepis) roberti. Lingulella rogersi Grabau [1900, pp. 624-625] Obolus (Westonia) rogersi. (Lingulella) rogersi [Obolus], Walcott [lS98b, pp. 413^15] Do. (Lingulella) rotundatus [Obolus], Walcott [1898b, p. 415] Obolus rotundatus. (Lingulella) schmalenseei [Obolus], Walcott [1902, p. 605] Obolus schmalenseei. (Lingulella) schucherti [Obolus], Walcott [1901, pp. 689-690] Lingulella schucherti. Lingulella selwyni Matthew [1895b , pp . 255-256] Obolus selwyni . Matthew [1903, pp. 62-63] Do. Matthew [1903, pp. 116-123] Do. (Lingulella) septalis [Obolus], Walcott [1905a, p. 331] Obolus septalis. (Lingulella) siemiradzkii [Obolus], Walcott [1901, pp. 699-691] Lingulella siemiradzkii. (Lingulella) similis [Obolus], Walcott [1898b, pp. 415-416] Lingulella similis. (Lingulella) since [Obolus], Walcott [1898b, pp. 416^17] Obolus since. (Lingulella) spatulus [Obolus], Walcott [1902, p. 607] Lingulella (Lingulepis) spatula. Lingulella? spissa Billings [1872b, pp. 468^69] Obolus (Lingulobolus) spissus. Billings [1874, pp. 67-68] Do. Billings [1882, p. 15] Do. Lingulella starri Matthew [1891, pp. 146-147] Lingulella (Lingulepis) starri. Lingulella starri minor Matthew [1892, pp. 58-59] Lingulella minor. Lingulella stoneana Hall and Clarke [1892c, PL II, figs. 9-11] Obolus (Westonia) stoneanua. Weller [1903, p. 112] Do. "WTiitfield [1882, pp. 344-345] Do. (Lingulella) tarpa [Obolus], Walcott [1898b, pp. 417-418] ..Lingulella tarpa. Lingulella texana Walcott [1908d, p. 71] — .Lingulella texana. Lingulella tumida Matthew [1899b, p. 200] Lingulella tumida. Matthew [1903, p. 123] Do. Lingulella unguiculus Salter [1866a, p. 285] Lingulella ferruginea. (Lingulella) upis [Obolus], Walcott [1905a, pp. 331-332] Lingulella upis. Lingulella wanniecki Redlich [1899, p. 7] Lingulella wanniecki. (Lingulella) wanniecki [Obolus], Walcott [1905a, p. 332] Do. (Lingulella) welleri [Obolus], Walcott [1902, p. 608] Lingulella welleri. (Lingulella) willisi [Obolus], Walcott [1898b, pp. 418-419] Obolus mllisi. Lingulella winona Schuchert [1897, p. 258] Lingulella winona. (Lingulella) winona convexus [Obolus], Walcott [1901, p. 691] Lingulella winona convexa. 62 CAMBRIAN BRACHIOPODA. Present reference. (Lingulella) zetus [Obolus], Walcott [1898b, p. 419] Obolus zetus. Lingulella zeus Walcott [new] Lingulella zeus. Lingulella sp. Kayser [1883, p. 35] Obolus? sp. undt. f. Kaj'ser [1883, pp. 35-36] Lingulella davisi. Lingulella sp. [Lingula or], Linnarsson [1876, pp. 15-16] Doubtfully referred to Lingulella ferruginea. Lingulella sp. undt. Linnarsson [1879, p. 25] Lingulella ferruginea. Lingulella (?) sp. Pompeckj [1896b, p. 509] Lingulella of. ferruginea. Lingulella? sp. No. 1 Wiman [1902, p. 52] Obolus (Westonia) wimani. Lingulella? sp. No. 2 Wiman [1902, p. 52] Do. Lingulella? sp. No. 3 Wiman [1902, p. 52] Obolus (Westonia) alandensis. Lingulella? sp. No. 4 Wiman [1902, p. 52] Obolus (Westonia) balticus. Lingulella? sp. No. 5 Wiman [1902, p. 52] Obolus (Westonia) alandensis. Lingulella? sp. No. 6 Wiman [1902, p. 52] Obolus (Westonia) balticus. Lingulella? sp. No. 7 Wiman [1902, p. 52] Obolus (Westonia) wimani. Lingulella (Acrothyra?) inflata Matthew [1902b, p. 390] Acrotreta inflata. Lingulella (Lingulepis) Walcott [1908e, PI. XI and pp. 142 and 144] Lingulella (Lingulepis). Lingulella (Lingulepis) acuminata sequens Walcott [1908d, p. 72] Lingulella (Lingulepis) acuminata sequens. Lingulella (Westonia) ella Grabau and Shimer [1907, p. 193] Obolus (Westonia) ella. Lingulepis Dall [1870, pp. 154 and 161] Lingulella (Lingulepis). Grabau and Shimer [1907, p. 193] Do. Hall [1863, p. 129] Do. Hall [1867, p. 106] Do. Halland Clarke [1892a, pp. 231-232] Do. ' Hall and Clarke [1892b, pp. 547-548] Do. Hall and Clarke [1892c, pp. 59-62, and 164] Do. Matthew [1902c, p. 102] Do. Matthew [1903, p. 126] Do. Meek [1871, pp. 186-187] Do. Meek and Hayden [1865, pp. 1 and 2] Do. Schuchert [1897, p. 258]... Do. Walcott [1897a, p. 404] Do. Zittel [1880, p. 664] Do. (Lingulepis) [Lingula], Oehlert [1887, p. 1261] Do. (Lingulepis) [Lingulella], Walcott [1908e, PI. XI, and pp. 142 and 144]. . . . Do. (Lingulepis) [Obolus], Walcott [1899, pp. 443-444] Do. Walcott [1901, p. 683] Do. Lingulepis acuminata Dwight [1886, p. 208] Lingulella (Lingulepis) acuminata. Matthew [1895b, pp. 257-258] Do. Schuchert [1897, p. 259] Dei. Walcott [1897a, p. 404] Do. Lingulepis acuminata meeki Delgado [1904, pp. 366-367] Lingulella delgadoi. (Lingulepis) acuminata sequens [Lingulella], Walcott [1908d, p. 72] Lingulella (Lingulepis) acuminata se- quens. (Lingulepis) acuminatus [Obolus], Walcott [1899, p. 443] Lingulella (Lingulepis) acuminata. (Lingulepis) acuminatus meeki [Obolus], Walcott [1899, p. 444] Lingulella (Lingulepis) acuminata meeki. Lingulepis acutangulus Schuchert [1897, p. 259] Lingulella acutangula. Lingulepis afiinis Walcott [1889a, p. 381] Obolus (Lingulobolus) affinis. Lingulepis cuneolus Schuchert [1897, p. 259] Lingulella perattenuata (in part). Whitfield [1877, pp. 8-9] Lingulella cuneola. Whitfield [1880, p. 336] Do. Lingulepis ella Hall and Whitfield [1877, p. 232] Obolus (Westonia) ella. Walcott [1897a, p. 404] Do. (Lingulepis) eros [Obolus], Walcott [1905a, p. 333] Lingulella (Lingulepis) eros. Lingulepis gregwa Matthew [1903, pp. 56-57, and 126-131] Lingulella (Lingulepis) gregwa. (Lingulepis) gregwa [Obolus], Walcott [1901, pp. 692-694] Lingulella atava (in part), L. tumida (la part), L. cania (in part), L. (Lingulepis)- gregwa (in part), and L. (L.) exigua. Lingulepis gregwa robusta Matthew [1903, pp. 57 and 131] Lingulella (Lingulepis) gregwa robusta. Lingulepis longinervis Matthew [1903, pp. 133-135] Lingulella (Lingulepis) longinervis. Lingulepis lusitanica Delgado [1904, pp. 36.5-366] Delgadella lusitanica. Lingulepis msera Hall and Wliitfield [1877, p. 206] Obolus msera. Walcott [1884b, pp. 12-13] Do. Lingulepis matinalis Hall [1863, p. 130] Obolus matinalis. Hall [1867, p. 107] Do. SYNONYMIC REFEEENCES. 63 Present reference. Lingulepis meeki Walcott [1897a, p. 405] Lingulella (Lingulepis) acuminata meeki. Lingulepis minima Dwight [1886, p. 208] Lingulella (Lingulepis) acuminata. Whitfield [1884, p. 141] Do. Lingulepis? minuta Hall and Whitfield [1877, pp. 206-207] Linnarssonella minuta. Walcott [1884b, p. 13] Linnarssonella minuta (in part). Lingulepis perattenuatus Whitfield [1877, p. 9] Lingulella perattenuata. Whitfield [1880, p. 337] Do. Lii^ulepis pinnaformis Hall [1863, pp. 129-130, PI. VI, figs. 12 and 13] Obelus matinalis. Hall [1863, pp. 129-130, PI. VI, figs. 14-16] Lingulella (Lingulepis) acuminata. Hall [1867, p. 107, PL I, figs, 12 and 13] Obolus matinalis. Hall [1867, p. 107, PI. I, figs. 14-16] Lingulella (Lingulepis) acuminata. Wliitfield [1880, p. 335] ,, Do. Whitfield [1882, pp. 169-170] Do. Lingulepis pinniformis Dwight [1886, p. 208] Do. Grabau and Shimer [1907, p. 193] Do. Hall and Clarke [1892a, p. 232] Do. Hall and Clarke [1892b, p. 548] Do. Hall and Clarke [1892c, p. 60] Do. Meek and Hayden [1865, pp. 2-3] Do. Schuchert [1897, p. 260] Do. Lingulepis prima Grabau and Shimer [1907, p. 193] Do. Meek and Hayden [1865, p. 3] Dicellomus politus. Miller [1877, p. 115] Lingulella prima. Schuchert [1897, p. 260] Lingulella prima (in part). (Lingulepis) primus [Obolus], Walcott [1901, p. 673] Lingulella prima. Lingulepis pumila Matthew [1903, p. 75] Lingulella (Lingulepis) pumila. Lingulepis roberti Matthew [1903, p. 132] Lingulella (Lingulepis) roberti. Lingulepis rotunda Matthew [1903, p. 199] Lingulella rotunda. (Lingulepis) rowei [Obolus], Walcott [1905a, p. 334] Lingulella (Lingulepis) rowei. Lingulepis starri Matthew [1903, p. 195] Lingulella (Lingulepis) starri. Lingulepis starri exigua Matthew [1903, pp. 197-198] Lingulella (Lingulepis) exigua. Lingulepis starri var. Matthew [1903, pp. 193-197] Do. (Lingulepis) sp. undt. [Obolus], Walcott [1906, pp. 567-568] Lingulella (Lingulepis) sp. undt. lingulicomes [Tellinomya], McCoy [1854, p. 274] Lingulella davisi. Lingulobolus Matthew [1895b, pp. 260-261] Obolus (Lingulobolus). (Lingulobolus) [Obolus], Walcott [1901, p. 683] Do. Walcott [1908e, PI. XI, and pp. 142 and 144] Do. Lingulobolus affinis Grabau [1900, pp. 621-622] Obolus (Lingulobolus) affinis. Matthew [1895b, pp. 261-262] Do. (Lingulobolus) affinis [Obolus], Walcott [1898a, p. 327] Do. Lingulobolus affinis cuneata Matthew [1895b, p . 262] Do. (Lingulobolus) spissus [Obolus], Walcott [1898a, p. 327] Obolus (Lingulobolus) spissus. linguloides [Davidsonella], Waagen [1885a, pp. 764-766] Neobolus warthi. linguloides [Lakhmina], Freeh [1897, PI. lA, figs. 4a-b] Do. Hall and Clarke [1892a, p. 234] Do. Hall and Clarke [1892b, p. 550] Do. Hall and Clarke [1892c, p. 28] Do. Oehlert [1887, p. 1265] Do. Waagen [1891, PI. II, figs. 3 and 4] Do. linguloides [Leptobolus], Matthew [1902b, p. 407] Lingulella ferruginea. Matthew [1903, p. 193] Do. linguloides [Leptobolus cf.], Matthew [1902b, p. 407] Do. Matthew [1903, pp. 192-193] Do. linguloides [Lingulella], Matthew [1886, p. 34] Do. linguloides [Lingulella cf .], Delgado [1904, pp. 369-370] Lingulella delgadoi. Linnarssonella Walcott [1902, pp. 601-602] Linnarssonella. Walcott [1908e, PI. XI, and pp. 142 and 146] Do. Linnarssonella broadheadi Walcott [1902, p. 601] Linnarssonella girtyi. Linnarssonella girtyi Walcott [1902, pp. 602-603] Do. Linnarssonella minuta Walcott [1902, pp. 603-604] Linnarssonella minuta. Linnarssonella modesta Walcott [1908d, pp. 90-91] Linnarssonella modesta. Linnarssonella nitens Walcott [1908d, p. 91] Linnarssonella nitens. Linnarssonella tennesseensis Walcott [1902, pp. 604-605] Linnarssonella tennesseensis. Linnarssonella transversa Walcott [1908d, p. 92] Linnarssonella transversa. 64 CAilBRIAN BRACHIOPODA. Present reference. Linnarssonella iirania Walcott [1908d, pp. 92-93] Linnarssonella urania. linnarssoni [Obolus (Lingulella)], Walcott [1901, p. 688] Lingulella linnarssoni. liniiarssoni [Orthis], Kayser [1883, p. 34] Eoorthia linnarssoni. linnai-ssoui [Orthis (Plectorthis)], Walcott [ 905a, p. 266] Do. Linnarssonia Dawson [1890, pp. 53-54] Acrotreta. Grabau and Shimer [1907, p. 200] Either Acrotreta or Acrotliele. (Seep. 631.) Hall and Clarke [1892a, p. 251] Acrotreta. Hall and Clarke [1892b, p. 567] Do. Hall and Clarke [1892c, pp. 107 and 109] Do. Matthew [1886, p. 35] Do. Matthew [1892, p. 42] Do. Walcott [1885a, p. 115] Do. Linnarssonia belli Matley [1902, p. 145] Acrotreta belli. Linnarssonia belli? Matthew [1892, pp. 42^3] (?) This species is not specifically referred in this monograph; it does not belong with Acrotreta belli. Linnarssonia cf . belti Matthew [1903, pp. 209-210] (?) This species is not specifically referred in this monograph; it does not belong with Acrotreta belti. Linnarssonia belti magna Matthew [1897b, pp. 169-170] Acrotreta sagittalis magna. Linnarssonia misera Hall and Clarke [1892c, pp. 108-109] Acrotreta misera. Matthew [1886, pp. 35-36] Do. Linnarssonia? nitida Walcott [1901, p. 673] Acrothele nitida. Linnarssonia pretiosa Grabau and Shimer [1907, p. 200] Either Acrotreta sagittalis or Acrothele pre- tiosa. (See p. 652.) Hall and Clarke [1892c, p. 70] Acrotreta sagittalis. Schuchert [1897, p. 262] Acrotreta sagittalis (in part) and Acrothele pretiosa (in part). Walcott [1901, p. 673] Acrotliele pretiosa. Linnarssonia cf . pretiosa Hall [1890, p. 55] Acrotreta sagittalis. (Linnarssonia) pretiosa [Obolella], Dawson [1890, pp. 53-54] Do. Linnarssonia sagittalis Freeh [1897, PL I A, fig. 3a] ; Do. Hall and Clarke [1892c, p. 108] Do. Walcott [1885a, p. 11.5] Do. Walcott [1889c, p. 442] Acrotreta depreesa. Walcott [1891a, PL LXVIIL figs. 2a-d] Acrotreta sagittalis. Linnarssonia sagittalis taconica Walcott [1889b, p. 36] Acrotreta sagittalis taconica. Walcott [1891a, pp. 610-611] Do. Linnarssonia sagittalis transversa Freeh [1897, PL lA, fig. 3b] Acrotreta sagittalis transversa. Walcott [1891a, desc. of PL LXVIII, figs. 2a, 2c-d] Do. -Linnarssonia taconica Oehlert [1889, p. 1138] Acrotreta sagittalis taconica. Walcott [1887, pp. 189-190] Do. Linnarssonia transversa Hall and Clarke [1892a, PL Til, figs. 22 and 23] Acrotreta sagittalis transversa. Hall and Clarke [1892c, p. 108] Do. Matthew [1886, p. 35] Do. Matthew [1895a, p. 125] Do. Walcott [1885a, p. 115] Do. logani [Iphidea], Walcott [1897b, pp. 711-712] Micromitra (Paterina) logani. longinervis [Lingulepis], Matthew [1903, pp. 133-135] Lingulella (Lingulepis) longinervis. longovalis [Lingulella], Matthew [1903, pp. 123-125] Lingulella triparilis. longus [Obolus (Palaeobolus) lens], Matthew [1903, pp. 146-147] Obolus (Palaeobolus) bretonensis lens. longus [Obolus (Schmidtia) obtusus], Mickwitz [1896, pp. 171-172] Obolus (Schmidtia) obtusus. loperi [Obolus], Walcott [1898b, pp. 389-390] Obolus loperi. (Loperia) [Protorthis], Walcott [1905a, p. 287] Protorthis (Loperia). Walcott [1908e, PL XI, and pp. 142 and 147] Do. (Loperia) dougaldensis [Protorthis], Walcott [1905a, pp. 287-288] Protorthis (Loperia) dugaldensis. Ionise [Micromitra (Iphidella)], Walcott [1908d, pp. 56-57] Micromitra (Iphidella) louise. lowi (Nisusia Jamesella), Walcott [1908d, p. 98] Nisusia (Jamesella) lowi. (Lucina) antiquissimus [Obolus], Eichwald [1843b, pp. 142-144] Obolus (Acritis) antiquissimus. lusitanica [Lingulepis], Delgado [1904, pp. 365-366] Delgadella lusitanica. lyncioides [Orthis lenticularis], Matthew [1892, p. 49] Orusia lenticularis lyncioides. Matthew [1903, p. 216] Do. lyncioides [Orthis (Orusia) lenticularis], Walcott [1905a, p. 277] Do. SYNONYMIC KEFERENCES. ■ 65 M. Present reference. mcconnelli [Lingulella], Matthew [1902c, p. 108] Obolus mcconnelli. Walcott [1889c, p. 441] Do. mcconnelli [Obolus], Walcott [1908c, PL I, fig. 2] Do. Walcott [1908c, PL I, fig. 2a] Obolus septalis. mcconnelli decipiens [Obolus], Walcott [new] -. Obolus mcconnelli decipiens. macra [Nisusia (Jamesella) perpasta], Walcott [1905a, p. 255] .Nisusia (Jamesella) perpasta macra. macra [Orthis perpasta], Pompeckj [1896b, p. 516] Do. maculata [Obolella], Davidson [1868, p. 311] Acrothele maculata. Davidson [1871, p. 341] Do. Delgado [1904, p. 364] Acrothele villaboimensis. Salter [1866a, p. 285] Acrothele maculata. msera [Lingulella?], Hall and Clarke [1892c, p. 61] Obolus msera. Walcott [1897a, p. 404] Do. msera [Lingulepis], Hall and Whitfield [1877, p. 206] Do. Walcott [1884b, pp. 12-13] Do. ma;ra [Obolus (Lingulella)], Walcott [1899, p. 443] Do. magna [Acrotreta sagittalis], Walcott [1902, pp. 595-596] Acrotreta sagittalis magna. magna [Linnarssonia belti], Matthew [1897b, pp. 169-170] Do. major [Billingsella], Walcott [1905a, p. 239] Billingsella major. Walcott [1908d, p. 101] Do. major [Iphidella], Walcott [1905a, p. 304] Micromitra (Paterina) major (in part) and M. (P.) williardi (in part). major [Mickwitzia?], Mickwitz [1896, p. 23] Rustella? major. major [Obolus?], Matthew [1890, p. 155] Do. maladensis [Iphidella pannula], Walcott [1905a, p. 306] .Micromitra (Iphidella) pannula maladensis. malvemensis [Acrotreta (?) sabrinee], Matley [1902, pp. 143-144] Acrotreta sabrinse. manitouensis [Schizambon], Walcott [new] . Schizambon manitouensis. manticula [Lingula?], Walcott [1884b, pp. 13-14] Lingulella punctata. White [1874, pp. 9-10] Lingulella arguta (in part) and L. manti- cula (in part). White [1877, pp. 52-53, PL III, fig. 2a] Lingulella arguta. The text also includes L. manticula. White [1877, p. 52, PI. Ill, fig. 2b] Lingulella manticula. The text includes L. arguta. marion [Billingsella], Walcott [1908d, p. 102] Billingsella marion. marjumensis [Acrotreta], Walcott [1908d, pp. 94-95] Acrotreta marjumensis. martinensis [Lingulella], Matthew [1890, pp. 155-156] Lingulella martinensis. Matthew [1895a, pp. 113-114] : Do. matinalis [Lingulella?], Walcott [1897a, p. 404] Obolus matinalis. matinalis [Lingulepis], Hall [1863, p. 130] Do. Hall [1867, p. 107] Do. matinalis? [Obolus], Walcott [1905a, p . 325] Obolus matinalis?. matinalis [Obolus (Lingulella)], Walcott [1899, p. 443] Obolus matinalis. matthewi [Acrothele], Grabau and Shimer [1907, p. 200, fig. 234f] Acrothele matthewi. Grabau and Shimer [1907, p. 200, fig. 234g] Acrothele prima. Hall and Clarke [1892a, PL 111, fig. 24] Acrothele matthewi. Hall and Clarke [1892c, pp. 99 and 100] Do. Matthew [1886, pp. 39-41] Do. Matthew [1895a, p. 128] Do. Matthew [1902b, pp. 397 and 402] Do. Matthew [1903, p. 104] Do. Walcott [1884a, p. 15] Do. Walcott [1886b, p. 109] Do. Walcott [1891a, p. 609] Do. matthewi [Lingula], Hartt [1868, p. 644] Do. Hartt [1878, p. 644] , Do. Hartt [1891, p. 644] Do. matthewi costata [Acrothele], Matthew [1895a, p. 128] Acrothele prima costata. Matthew [lS02b, p. 397] Do. Matthew [1903, p. 104] Do. matthewi eryx [Acrothele], Walcott [1905b, p. 11] Acrothele matthewi eryx. 62667°— VOL 51, pt 1—12 5 66 CAJVIBRIAN BRACHIOPODA. Present reference, matthewi lata [Acrothele], Hall and Clarke [1892a, PI. Ill, figs. 25 and 26]. Acrothele matthewi lata. Hall and Clarke [1892c, PI. Ill, figs. 26-28]. ... Do. Matthew [1886, p. 41] Do. Matthew [1895a, PI. V, figs. 8a-b] Do. Matthew [1903, p. 104] Do. matthewi multicostata [Acrothele], Matthew [1897b, p. 168] Acrothele matthewi multicostata. matthewi prima [Acrothele], Hall and Clarke [1892a, PI. Ill, fig. 27] Acrothele prima. Hall and Clarke [1892c, PI. Ill, fig. 25] Do. Matthew [1886, p. 41] Do. Matthew [lS95a, PI. V, figs. 7a-b] Do. Matthew [1902b, pp. 397 and 402] Do. Matthew [1903, p. 104] Do. maximus [Obolus apollinis], Mickwitz [1896, pp. 140-143] Obolus apoUinis maximus. meeki [Lingulepis], Walcott [1897a, p. 405] Lingulella (Lingulepis) acuminata meeki. meeki [Lingulepis acuminata], Delgado [1904, pp. 366-367] Lingulella delgadoi. meeki [Obolus (Lingulepis") acuminatus], Walcott [1899, p. 444] Lingulella (Lingulepis) acuminata meeki. Meekina prima Walcott [1905a, p. 313] Linnarssonella tennesseensis. melita [Dalmanella], Schuchert [1897, p. 202] Variety of Eoorthis desmopleura. melita [Leptajna], Hall and ^^'^litfield [1877, p. 208] Do. membranaceous [Obolus], Walcott [1908d, p. 61] Obolus membranaceus. meneghini [Obolus (?)], Walcott [1901, p. 684] Obolus? meneghinii. Metoptoma sabrinse Callaway [1874, p. 196] Acrotreta sabrinse. (Mickwitzella) [Obolus], Walcott [1908d, p. 70] Obolus (Mickwitzella). Walcott [1908e, PI. XI, and pp. 142 and 144] Do. mickwitzi [Obolus], Walcott [1898b, pp. 386-387] Obolus mickwitzi. Mickwitzia Hall and Clarke [1892a, p. 246] Mickwitzia. Hall and Clarke [1892b, p. 562] Do. Hall and Clarke [1892c, pp. 86-87] Do. Schmidt [1888, p. 24] Do. Walcott [1908e, PI. XI, and pp. 142 and 143] Do. Mickwitzia? major Mickwitz [1896, p. 23] Rustella? major. Mickwitzia monilifera Hall and Clarke [1892a, figs. 253-255, p. 246] Mickwitzia monilifera. Hall and Clarke [1892b, figs. 253-255, p. 562] Do. Hall and Clarke [1892c, p. 86] Do. Schmidt [1888, pp. 21-23 and 24-25] Do. Walcott [1891a, PI. LXX, figs. 2, 2a-h] Do. Wiman [1902, p. 53] Do. Mickwitzia occidens Walcott [1908d, p. 54] Mickwitzia occidens. Mickwitzia pretiosa Walcott [1908d, pp. 54-55] Mickwitzia pretiosa. Micromitra Meek [1873, p. 479] Micromitra. Walcott [1908e, PI. XI, and pp. 142 and 143] Do. (Micromitra) [Paterina], Schuchert [1905, p. 329] Do. Micromitra haydeni Walcott [1908d, pp. 55-56] Micromitra haydeni. Micromitra scotica Walcott [new] Micromitra scotica. Micromitra sculptilis endlichi Walcott [1908d, p. 56] Micromitra sculptilis endlichi. Micromitra zenobia Walcott [new] Micromitra zenobia. Micromitra (Iphidella) Walcott [1908e, PI. XI, and pp. 142 and 143]'. Micromitra (Iphidella). Micromitra (Iphidella) louise Walcott [1908d, pp. 56-57] ..' Micromitra (Iphidella) Ionise. Micromitra (Iphidella) nyssa Walcott [1908d, p. 57] Micromitra (Iphidella) nyssa. Micromitra (Iphidella) pannula Walcott [1908c, p. 244, PI. I, figs. 1, la-c]. Micromitra (Iphidella) pannula. Micromitra (Paterina) Walcott [1908e, PI. XI, and pp. 142 and 143] Micromitra (Paterina). Micromitra (Paterina) labradorica var. undt. Walcott [new] Micromitra (Paterina) labradoricavar.undt. Micromitra (Paterina) stissingensis ora Walcott [new] Micromitra (Paterina) stissingensis era. Micromitra (Paterina) stuarti Walcott [1908d, p. 58] Micromitra (Paterina) stuarti. Micromitra (Paterina) wapta Walcott [1908d, p. 59] Micromitra (Paterina) wapta. Micromitra (Paterina) williardi Walcott [1908d, p. 60] Micromitra (Paterina) williardi. microscopica [Discina], Shumard [1861, p. 221] Acrotreta microscopica. microscopica missouriensis [Acrotreta], Walcott [1902, p. 590] Acrotreta microscopica missouriensis. microscopica tetonensis [Acrotreta], Walcott [1902, p. 590] Acrotreta microscopica tetonensis. minima [Lingulepis], Dwight [1886, p. 208] Lingulella (Lingulepis) acuminata. Whitfield [1884, p. 141] Do. minimus [Obolus?], Barrande [1879b, PI. XCV, figs, ii: 1-5] Acrotreta? minima. minimus [Obolus], Walcott [1905a, pp. 325-326] Obolus minimus. SYNONYMIC REFERENCES. 67 Present reference. minimus [Obolus (Lingulella) lambomi], Walcott [1898b, p. 407] Obolus lamborni minimus. minor [AcrothjTa], Walcott [1905a, p. 303] Acrothyra minor. minor [Camarella], Hall and Clarke [1893b, p. 221] Obolella minor. minor [Camarella?], Walcott [1891a, p. 614] Do. minor [Camerella], Walcott [lS90b, pp. 36-37] Do. minor [Lingulella starri], Matthew [1892, pp. 58-59] Lingulella minor. minor [Obolella], Clark and Mathews [1906, p. 252] Obolella minor. minor [Obolus?], Barrande [1888a, p. 105] Obolus? minor. Barrande [1868b, p. 693] Do. minor [Protorhyncha?], Schuchert [1897, p. 334] Obolella minor. minuta [Acrothele?], Walcott [1905a, p. 303] Acrothele? minuta. minuta [Acrotreta], Walcott [1901, p. 673] Linnarssonella minuta. minuta [Lingulella], Schuchert [1897, p. 257] Do. minuta [Lingulepis?], Hall and TSTiitfield [1877, pp. 206-207] Do. Walcott [1884b, p. 13] Linnarssonella minuta (in part). minuta [Linnarssonella], Walcott [1902, pp. 603-604] Linnarssonella minuta. minuta [Obolella?], Walcott [1897a, p. 404] Do. minuta [Obolella], Walcott [1899, p. 443] Do. TTiinutissima [Kutorgina], Hall and Whitfield [1877, pp. 207-208] Micromitra sculptilis. minutus [Obolus (Schmidtia) obtusus], Mick^vitz [1896, pp. 175-177] Obolus (Schmidtia) obtusus. miqueli [Yorkia], Walcott [new] Yorkia miqueli. miranda [Lingula?], Barrande [1879b, PI. CXI] Obolus? mirandus. miser [Acrotreta], Walcott [1902, pp. 590-591] Acrotreta misera. miser [Obolella?], Billings [1872b, pp. 470^71] Do. Billings [1874, p. 69] Do. misera [Linnarssonia], Hall and Clarke [1892c, pp. 108 and 109] Do. Matthew [1886, pp. 35-36] Do. missouriensis [Acrotreta microscopica], Walcott [1902, p. 590] Acrotreta microscopica missouriensis. mobergi [Obolella], Walcott [1901, pp . 673-674] Obolella mobergi. Mobergia Redlich [1899, pp. 5-6] Botsfordia. Mobergia granulata Redlich [1899, pp. 5-6] Botsfordia granulata. modesta [Linnarssonella], Walcott [1908d, pp. 90-91] Linnarssonella modesta. Monobolina refulgens Matthew [1903, pp. 210-213] Obolus refulgens. (Monobolina) refulgens [Obolus], Matthew [1902c, p. 98] Do. monilifer [Obolus?], Linnarsson [1871, pp. 9-10] Mickwitzia monilifera. monilifera [Lingula?], Linnarsson [1869a, p. 344] Do. monilifera [Lingula], Linnarsson [1869b, p. 398] Do. monilifera [Mickwitzia], Hall and Clarke [1892a, figs. 253-255, p. 246] Do. Hall and Clarke [lS92b, figs. 253-255, p. 562] Do. Hall and Clarke [1892c, p. 86] Do. Schmidt [1888, pp. 21-23 and 24-25] Do. Walcott [1891a, PI. LXX, figs. 2, 2a-h] Do. Wiman [1902, p. 53] Do. montanensis [Polyta?chia?], Walcott [1905a, pp. 295-296] Clarkella? montanensis. mosia [Lingula], Hall [1863, p. 126] Lingulella mosia. Hall [1867, pp. 102-103] Do. Sardeson [1896, p. 95] Do. mosia osceola [Obolus (Lingulella)], Walcott [1898b, p. 409] Lingulella mosia osceola. multicostata [Acrothele matthewi], Matthew [1897b, p. 168] Acrothele matthewi multicostata. murrayi [Obolus?], Billings [1865b, p. 362] Obolus? murrayi. N. namouna [Obolus], Walcott [1898b, p. 390] Obolus namouna. nana [Obolella], Billings [1862d, pp. 67-68] Dicellornus nanus. Hall and Clarke [1892c, pp. 69-70] Do. Hayden [1862, p. 73] Do. Meek and Hayden [1862, pp. 435-136] Do. Meek and Hayden [1865, p. 4] Do. Walcott [1886b, p. Ill] Do. "\^Tiitfleld [1880, pp. 340-341] Do. nanno [Obolus (Lingulella)], Walcott [1898b, p. 409] Lingulella nanno. 68 CAJVIBRIAN BRACHIOPODA. Present reference. nanus [Dicellomus], Walcott [1899, p. 447] Lingulella desiderata (in part) and Dicello- mus nanus (in part). Walcott [1905a, pp. 314-315] Dicellomus nanus. nathorsti [Lingulella?], Linnarsson [1876, pp. 15-16] Lingulella nathorsti. nautes [Protorthis], Walcott [1905a, pp. 283-284] Nisusia (Jamesella) nautes. neboensis [Acrotreta], Walcott [1905a; pp. 300-301] Acrotreta neboensis. nebulosa [Genre? sp.], Barrande [186Sa, pp. 10.5-106] Orbiculoidea contraria. Barrande [lS68b, pp. 693-694] Do. Neobolus Hall and Clarke [1892a, p. 245] Neobolus. Hall and Clarke [1892b, p. 561] Do. Hall and Clarke [1892c, p. 84] Do. Oehl€«-t [1887, p. 1263] Do, Waagen [1885, pp. 756-758] Do. Walcott [1908d, pp. 72-76] Do. Walcott [1908e, PI. XI, and pp. 142 and 144] Do. Neobolus warthi Freeh. [1897, PI. lA, figs. 5a-b] Neobolus warthi. Hall and Clarke [1892a, p. 245] Do. Hall and Clarke [1892b, p. 561] Do. Hall and Clarke [1892c, p. 84] Do. Oehlert [1887, p. 1263] Do. Waagen [1885, pp. 758-7.59] Do. Waagen [1891, PI. II, figs. 5-9] Do. Neobolus wynnei Waagen [1885, pp. 7.59-761] : Do. Waagen [1891, PI. II, figs. 10 and 11] Do. newberryi [Eoorthis], Walcott [1908d, p. 105] Eoorthis newberryi. newtonensis [Orthis], Weller [1903, pp. 113-114] Eoorthis newtonensis. newtonensis [Orthis (Plectorthis)], Walcott [1905a, p. 267] Do. nicholsoni [Acrotreta?], Davidson [1868, pp. 313-314] Acrotreta nicholsoni. Davidson [1871, pp. 343-344] Do. nicholsoni [Acrotreta], Davidson [1883, p. 213] Do. Hall and Clarke [lS92c, p. 103] Do. Swanston [1877, PL VII, figs. 21a-c] Do. Swanston [1886, PI. VII, figs. 21a-c] Do. nicholsoni [Acrotreta sp. cf.], Matley [1902, p. 142] Acrotreta sabrinae. nicholsoni [Lingulella], Callaway [1874, p. 196] Lingulella nicholsoni. Callaway [1877, pp. 668-669] Do. Davidson [1883, pp. 208-209] Do. nicholsoni? [Lingulella], Matley [1902, p. 141] Do. ninus [Obolus tetonensis], Walcott [1905a, p. 328] Obolus tetonensis ninus. nisus [Iphidella], Walcott [1905a, p. 305] Micromitra nisus. Nisusia Grabau and Shimer [1907, p. 210] Nisusia. Walcott [1905a, pp. 247-248] Do. Walcott [1908e, PL XI, and pp. 142 and 147] Do. Nisusia alberta Walcott [1905a, pp. 248-249] Nisusia alberta. Walcott [1908c, p. 245] Do. Nisusia festinata Grabau and Shimer [1907, p. 211] Nisusia festinata. Walcott [1905a, pp. 249-251] Do. Nisusia festinata transversa Walcott [1905a, p. 251] Nisusia festinata transversa. Nisusia rara Walcott [1908d, p. 97] Nisusia rara. Nisusia (Jamesella) Walcott [1905a, p. 252] Nisusia (Jamesella). Walcott [1908e, PL XI, and pp. 142 and 147] Do. Nisusia (Jamesella) amii Walcott [1905a, p. 252] Nisusia (Jamesella) amii. Nisusia (Jamesella) argenta Walcott [1905a, p. 252] Nisusia (Jamesella) argenta. Nisusia (Jamesella) erecta Walcott [1905a, p. 253] Nisusia (Jamesella) erecta. Nisusia? (Jamesella?) kanabensis. Walcott [1908d, pp. 97-98] Nisusia? (Jamesella?) kanabensij. Nisusia (Jamesella) kuthani Walcott [1905a, pp. 253-254] Nisusia (Jamesella) kuthani. Nisusia (Jamesella) lowi Walcott [1908d, p. 98] Nisusia (Jamesella) lowi. Nisusia (Jamesella) perpasta Walcott [1905a, pp. 254-255] Nisusia (Jamesella) perpasta. Nisusia (Jamesella) perpasta macra Walcott [1905a, p. 255] Nisusia (Jamesella) perpasta macra. Nisusia (Jamesella) perpasta subquadrata Walcott [1905a, p. 255] Nisusia (Jamesella) perpasta subquadrata. Nisusia (Jamesella) utahensis Walcott [1905a, pp. 255-256] Nisusia (Jamesella) utahensis. . Nisusia (Jamesella) sp. undt. Walcott [1905a, p. 256] Nisusia (Jamesella) sp. undt. nitens [Linnarssonella], Walcott [1908d, p. 91] .Linnarssonella nitens. nitida [Linnarssonia?], Walcott [1901, p. 673] Acrothele nitida. SYNONYMIC EEFERENCES. 69 Present reference, nitida [Obolella], Ford [1873, p. 213] , Acrothele nitida. Grabau and Shimer [1907, p. 189] Do. Hall and Clarke [1892c, p. 70] - Do. Walcott [1886b, pp. 118-119] Do. Walcott [lS91a, p. 612] Do. notchensis [Obolus (Westonia)], Walcott [190Sd, p. 69] Obolus (Westonia) notcliensis. nox [Acrotreta], Walcott [1905a, p. 301] Acrotreta nox. nundina [Obolus], Walcott [1905a, p. 326] Obolus nundina. nundina [Syntrophia], Walcott [1905a, p. 292] Syntrophia nundina. nuunebergensis [Protorthis?], Walcott [1905a, p. 284] Protorthis? hunnebergensis. nympha [Orthis (Plectorthis) desmopleura], Walcott [1905a, p. 262] Eoorthis desmopleura nympha. nyssa [Micromitra (Iphidella)], Walcott [1908d, p. 57] Micromitra (Iphidella) nyssa. O. Obolella Billings [1861b, p. 7] Obolella. Billings [1861c, p. 946] Do. Billings [1862c, pp. 420^21] Do. Billings [_1862e, p. 218] Do. Billings [1872a, pp. 217-218] Do. Billings [1872c, pp. 355-357] Do. Billings [1876, pp. 176-178] Do. Dall [1870, pp. 154 and 163] Do. Davidson [1866, p. 60] Do. Davidson [1868, pp. 308-309] Do. Davidson [1871, pp. 338-339] Do. Ford [1881, pp. 131-134] Do. Grabau and Shimer [1907, p. 188] Do. Hall [1863, p. 131] , Do. Hall [1867, p. 108] Do. Hall and Clarke [1892a, pp. 240-241] Obolella (in part) and Dicellomus (in part). Hall and Clarke [1892b, pp. 556-557] Do. Hall and Clarke [1892c, pp. 66-73 and 164-165] Obolella (in part), Dicellomus (in part), Bicia (in part), Obolus (in part), etc. Matthew [1892, pp. 39-40] Obolella. Meek and Hayden [1865, pp. 3^] Do. Mickwitz [1896, pp. 116, 121, and 123-126] .■ Do. Oehlert [1887, p. 1262] ■. Do. Obolella? Walcott [1884b, pp. 67-68] Do. Obolella Walcott [1886b, pp. 109-112] Do. Walcott [1908e, PI. XI, and pp. 142 and 145] Do. Zittel [1880, p. 664] Do. Obolella? ambigua Walcott [1884b, pp. 67-68] Elkania ambigua. Obolella asiatica Walcott [1905a, p. 297] Obolella asiatica. Obolella atlantica Burr [1900, p. 47] Obolella atlantica. Gorham [1905, PL I, figs. 2a-c] Do. Grabau [1900, pp. 620-621] Do. Grabau and Shimer [1907, p. 188] Do. Matthew [1899d, p. 70] Do. Walcott [1890b, p. 36] Do. Walcott [1891a, p. 611] Do. Obolella cf . atlantica Delgado [1904, p. 364] Obolella? sp. undt. Obolella belti Davidson [1868, pp. 310-311] Acrotreta belti. Davidson [1871, pp. 340-341] Do. Obolella cffilata Billings [1872a, p. 218] Botsfordia cselat*. Obolella chromatica Billings [1861b, pp. 7-8] Obolella chromatica. Billings [1861c, p. 947] Do. Billings [1862e, p. 219] Do. Billings [1863, p. 284] Do. Billings [1876, pp. 176-178] Do. Ford ["l881, p. 133] Do. Hall [1863, p. 132] Do. Hall [1867, p. 110] Do. Hall and Clarke [1892c, p. 67] Do. von Toll [1899, p. 27] (?) (See p. 592.) 70 CAMBRIAN BRACHIOPODA. Present reference. Obolella chromatica Walcott [1885a, pp. 115 and 117] Obolella crassa. Walcott [lS86b, p. 112] Obolella chromatica. Walcott [lS91a, p. 611] Do. Walcott [1899, p. 446] Do Walcott [1905a, p. 313] Do. Obolella cingulata Billings [1863, p. 284, figs. 2S7a-b] Kutorgina cingulata. Billings [1863, p. 284, fig. 287c] Rustella edsoni. Obolella circe Billings [1872a, pp. 219-220] Quebecia circe. Billings [lS72c, pp. 357-358] Do. Walcott [1886b, p. 118, PL X, fig. 3] Obolella chromatica. The text includes Quebecia circe. Walcott [1886b, p. 118, PI. X, fig. 3a] Quebecia circe. Walcott [1891a, p. 611, PL LXXI, fig. 3] Obolella chromatica. The text includes Quebecia circe. Walcott [1891a, p. 611, PL LXXI, fig. 3a] Quebecia circe. Obolella circe? Walcott [1891a, fig. 62, p. 611] Obolella crassa. Obolella?? complexus Hall and Clarke [1892c, p. 73] Obelus complexus. Obolella crassa Billings [1872a, p. 218] Obolella crassa. Billings [1872c, p. 356] Do. Boruemann [1891, pp. 439^40] Obolus? zoppi. Ford [1878, p. 128] Obolella crassa. Ford [1881, pp. 131-133] Do. Ford [1886a, fig. 2, p. 466] Do. ^ Gorham [1905, PL I, figs, la-f] Obolella atlantica. Grabau and Shimer [1907a, pp. 188-189] Obolella crassa. Hall and Clarke [1892a, PL III, figs. 5-7] Do. Hall and Clarke [1892c, p. 70] Do. Shaler and Foerste [1888, p. 27] Obolella atlantica. Walcott [1885b, p. 21] Obolella crassa. Walcott [1886b, p. 114] Do. Walcott [1891a, p. 612] Do. Walcott [1905a, p. 321] Do. Obolella crassa? Grabau [1900, pp. 619-620] Do. Obolella crassa elongata Walcott [new] Obolella crassa elongata. Obolella desiderata Billings [1862d, pp. 69-70] Elkania desiderata. Davidson [1868, p. 309] Do. Obolella? desiderata Walcott [1886b, p. Ill] Do. Obolella desquamata Billings [1872a, p. 218] Obolella crassa. Billings [1872c, p. 356] Do. Obolella discoida Hall and 'WTaitfield [1877, p. 205] Obolus discoideus. Obolella? discoidea Hall and Clarke [1892c, p. 69] Do. Obolella discoidea Walcott [1884b, p. 14] Do. Obolella? discoidea Walcott [1886b, p. Ill] Do. Obolella gamagei Hobbs [1899, pp. 114-115] Acrothele gamagei. Obolella gemma Billings [1872a, pp. 218-219] Bicia gemma. Billings [1872c, p. 355] Do. Hall and Clarke [1892c, pp. 69 and 71] Do. Walcott [1886b, pp. 116-117] Do. Walcott [1891a, p. 612] Do. Obolella? gemmula Matthew [1892, pp. 41^2] Lingulella ferruginea. Obolella (?) groomi Matley [1902, pp. 137 and 139] Obolella groomi. Obolella ida BilHngs [1862d, p. 71] Elkania ida. Obolella ida? Dawson [1888a, p. 55] Acrotreta sagittalis. Dawson [1888b, p. 55] Do. Obolella? ida Walcott [1886b, p. Ill] Elkania ida. Obolella lindstromi Walcott [1901, pp. 674-675] Obolella? lindstromi. Obolella maculata Davidson [1868, p. 311] Acrothele maculata. Davidson [1871, p. 341] Do. Delgado [1904, p. 364] Acrothele villaboimensis. Salter [1866a, p. 285] Acrothele maculata. Obolella minor Clark and Mathews [1906, p. 252] Obolella minor. Obolella minuta Walcott [1899, p. 443] Linnarssonella minuta. Obolella? minuta Walcott [1897a, p. 404] Do. SYNONYMIC REFERENCES. Present reference. Obolella? miser Billinga [1872b, pp. 470-471] Acrotreta misera. Billings [1874, p. 69] Do. Obolella mobergi Walcott [1901, pp. 673-674] Obolella mobergi. Obolella nana Billinga [1862d, pp. 67-68] Dicellomus nanus. Hall and Clarke [1892c, pp. 69-70] Do. Hayden [1862, p. 73] Do. Meek and Hayden [1862, pp. 435^36] Do. Meek and Hayden [1865, p. 4] Do. Walcott [1886b, p. Ill] Do. "WTiitfield [1880, pp. 340-341] Do. Obolella nitida Ford [1873, p . 213] Acrothele nitida. Grabauand Shimer [1907, p. 189]... Do. Hall and Clarke [1892c, p. 70] Do. Walcott [1886b, pp. 118-119] Do. Walcott [1891a, p. 612] Do. Obolella par-^oila Wallerius [1895, pp . 65-66] Acrotreta parsiila. Obolella pectenoides Schucbert [1897, p. 27.5] ^ Dicellomus pectenoides. Obolella? phillipsi Davidson [1866, pp . 62-63] Micromitra (Paterina) phillipsi. Obolella phillipsi Holl [1865, p. 102] Do. Phillips [1871, p. 68] Do. Obolella phillipsia Dall [1877, p. 41] ; Do. Obolella polita Billings [1862c, p. 421] Dicellomus politus. Obolella? polita Hall [1863, pp. 133-134] Do. Hall [1867, pp. 112-113] Do. Obolella polita Hall and Clarke [1892c, pp. 72 and 73] Do. Walcott [1886b , p . Ill] Do. Whitfield [1880, pp. 339-340] Do. Obolella pretiosa Billings [1862d, pp. 68-69] Acrothele pretiosa. Billings [1863, p. 230] Do. Chapman [1863, p. 191] Do. Chapman [1864, p. 163] Do. Obolella? pretiosa Walcott [1886b, p. Ill] Do. Obolella prima 'Whitfield [1884, pp. 142-143] Lingulella prima. Obolella sabrinse Callaway [1877, p. 669] Acrotreta sabrinse. Davidson [1883, p. 211] Do. Hall and Clarke [1892c, p. 103] Do. Obolella sagittalis Brogger [1882, p . 45] Acrotreta sagittalis. Davidson [1868, pp. 309-310] Do. Davidson [1871, pp. 339-340] Do. Davidson [1883, p. 211] Do. Linnarsson [1876, pp. 19-20] Do. Linnarsson [1879, pp. 27-28] Do. Salter [1866a, p. 285] Do. Obolella cf. sagittalis Wiman [1902, p. 66] Do. Obolella sagittalis belli Davidson [1871, desc. of PI. L, figs. 15-17] Acrotreta belli. Obolella? salteri Davidson [1868, p. 311] Obolus (Broggeria) salteri. Obolella salteri Holl [1865, p. 102] Do. Obolella ('?) salteri Matley [1902, pp. 139-140] '. Do. Obolella salteri Phillips [1871, p. 68] 'Do. Obolella salteri? Davidson [1866, pp. 61-62] Do. Obolella? scabrinse Walcott [1884b, PI. I, fig. Ic] Acrotreta sabrinse. Obolella transversa Hartt [1868, p. 644] Acrotreta sagittalis transversa. Hartt [1878, p. 644] Do. Hartt [1891, p. 644] Do. Walcott [1884a, p. 16] Do. Obolella vermilionensis Walcott [new] Obolella vermilionensis. ■ Obolella wirrialpensis Etheridge [1905, p. 248] Obolella wirrialpensis. Obolella winlalpensis calceoloides Etheridge [1905, p. 249] Do. Obolella sp. 3 Billings [1861b, p. 7] Dicellomus politus. Billings [1861c, p. 946] Do. Billings [1862e, p. 218] Do. Obolella sp. (?) Bomemann [1891, p. 440]. Obolus? meneghinii. Obolella sp. Shaler and Foerste [1888, pp. 27-28] Obolella atlantica. 72 CAMBRIAN BRACHIOPODA. Present reference. Obolella (Acrotreta?) sagittalis Moberg and Segerberg [1906, p. 64] Acrotreta sagittalis. Obolella (Glyptias) Walcott [1901, p. 675] Obolella (Glyptias). Walcott [1908e, PI. XI, and pp. 142 and 145] Do. Obolella (Glyptias) favosa Walcott [1901, pp. 675-676] Obolella (Glyptias) iavosa. Obolella (Kutorgina) Dall [1870, pp. 154 and 163] Kutorgina. Obolella (Kutorgina) cingulata Billings [1861b, pp. 8-9, figs. 8 and 10] Kutorgina cingulata. Billings [1861b, p. 8, fig. 9] Rustella edsoni. Billings [1861c, p. 948, figs. 347 and 349]. . . Kutorgina cingulata. Billings [1861c, p. 948, fig. 348] Rustella edsoni. Billings [1862e, p. 220, figs. 347 and 349]. . . Kutorgina cingulata. Bikings [1862e, p. 220, fig. 348] Rustella edsoni. Obolella (Linnarssonia) pretiosa Dawson [1890, pp. 53-54] Acrotreta sagittalis. Obolella (Orbicula) cselata Ford [1871, p. 33] Botsfordia cselata. Obolella (Orbicula?) crassa Ford [1871, p. 33] Obolella crassa. Obolellus? phillipsi Roemer [1876, PI. II, figs. 6a-d] Micromitra (Paterina) phillipsi. Obolus Dall [1870, pp. 154 and 162] Obelus. Davidson [1853, pp. 135-136] Obolus (in part), O. (Acritis) (in part), and O. (Mickwitzella) (in part). Davidson [1866, p. 58] Obolus. Davidson [1883, p. 218] Do. Eichwald [1829, p. 274] Do. Eichwald [1860, pp. 924-925] Obolus (in part), O. (Acritis) (in part) and O. (Mickwitzella) (in part). Hall and Clarke [1892a, pp. 242-243] Obolus. Hall and Clarke [1892b, pp. 558-559] Do. Hall and Clarke [1892c, pp. 80-81 and 337-339] Do. Kutorga [1848, pp. 250-253] Do. Matthew [1892, pp. 43-44] Do. Matthew [1903, p. 135] Do. Mickwitz [1892, pp. 57-64]., Do. Mickwitz [1896, pp. 1-133 (127-129)] Do. Morris [1849, pp. 319-320] Do. Oehlert [1887, p. 1261] Do. de Verneuil [1845, p. 291] Do. Walcott [1898b, pp. 385-386] Do. Walcott [1901, pp. 681-683] Do. Walcott [1908e, PI. XI, and pp. 142 and 144 ] Do. Zittel [1880, p. 664] Do. Obolus acadica Walcott [1905a, pp. 324-325] Obolus acadicus. Obolus? advena Barrande [1879b, PI. XCV, fig. iv] Obolus? advenus. Obolus eequiputeis Matthew [1902c, p. 94] Obolus selwjTii. Matthew [1903, p. 139] Do. Obolus anceps Walcott [1898b, pp. 388-389] Obolus anceps. Obolus antiquissimus Eichwald [1859, PI. XXXVII, figs. 5a-d] Obolus (Acritis) antiquissimus. Eichwald [1860, pp. 928-929] Do. Obolus apoUinis Billings [1872a, p. 218] . . /. Obolus apollinis. Billings [1872c, p. 356] Do. Davidson [1853, figs. 51 and 52, p. 136, and PI. IX, figs. 280-284] , Do. Da-vidson [1853, PI. IX, fig. 285] Obolus (Acritis) antiquissimus. Eichwald [1829, p. 274] Obolus apollinis. Eichwald [1840, p. 167] Do. . Eichwald [1843b, p. 140] - Do. Eichwald [I860, pp. 925-926] Do. Gagel [1890, pp. 21-22] Do. Hall and Clarke [1892a, figs. 247 and 248, p. 242] Do. Hall and Clarke [1892b, figs. 247 and 248, p. 558] Do. Hall and Clarke [1892c, p. 80] Do. Kutorga [1848, pp. 251 and 252] Do. Matthew [1892, pp. 43-44] Do. Mickwitz [1896, pp. 133-137] Do. Moberg and Segerberg [1906, p. 65] Do. Morris [1849, p. 316] Do. Noetling [1883, p. 265] Do. SYNONYMIC REFERENCES. 73 Present reference. Obolus apollinis Roemer [1876, PI. II, figs. 7a-c] Obolus apollinis. Roemer [1885, pp. 23-24 (270-271)] Do. Schmidt [1861, p. 218] Do. de Verneuil [1845, pp. 290-292] Obolus apollinis (in part), O. apollinis ingricus (in part), O. (Acritis) antiquis- Bimus (in part), and 0. (Mickwitzella) siluricus (in part) . Walcott [1898b, PI. XXVI, figs. 3-6] Obolus apollinis. Westerg^rd [1909, p. 56] Do. Zittel [1880, figs. 488a-c, p. 664] Do. Zittel [1880, fig. 488d, p. 664] Obolus apollinis quenstedti. ' Obolus apollinis ingricus Mickwitz [1896, pp. 137-140] Obolus apollinis ingricus. Obolus apollinis maximus Mickwitz [1896, pp. 140-143] Obolus apollinis maximus. Obolus apollinis quenstedti Mickwitz [1896, pp. 143-145] Obolus apollinis quenstedti. Obolus appolinus? Owen [1852, p. 501] Dicellomus politus. Obolus? bohemicus Barrande [1879b, PL CII, figs, vn: 1-3] Acrothele bohemica. Obolus bretonensis Matthew [1902c, p. 95] Obolus (Palseobolus) bretonensis. Obolus celatus orbiculatus Moberg and Segerberg [1906, p. 65] Obolus (Schmidtia) celatus. Westerg4rd [1909, p. 56] Do. Wiman [1902, p. 62] Do. Obolus? coraplexus Barrande [1879b, Pis. XCV, CXI, CXIII, and CLII]. .Obolus complexus. Obolus discus Matthew [1902c, p. 94] Lingulella triparilis. Obolus eichwaldi Mickwitz [1896, pp. 154-155] Obolus eichwaldi. Obolus elegans Mickwitz [1896, pp. 157-158] Obolus elegans. Obolus ella Matthew [1902c, pp. 96 and 110] Obolus (Westonia) ella. Obolus? inflatus Westerg^rd [1909, p. 76] Obolus? inflatus. Obolus ingricus Eichwald [1829, p . 274] Obolus apollinis ingricus. Eichwald [1843b, p. 140-141] Do. Eichwald [1860, pp. 926-927] Do. von Leuchtenberg [1843, p. 16] Do. Obolus ismene Walcott [1905a, p. 325] Obolus ismene. Obolus labradoricus Billings [lS61b, p. 6] Micromitra (Paterina) labradorica. Billings [1861c, p. 946] Do. Billings [lS62e, p. 218] Do. Billings [1863, p. 284] Do. Obolus lens Matthew [1902c, p. 95] Obolus (Palseobolus) bretonensis lens. Obolus lens-primus Matthew [1902c, pp. 94-95] Do. Obolus loperi Walcott [1898c, pp. 389-390] Obolus loperi. Obolus mcconnelli Walcott [1908c, PI. I, fig. 2] Obolus mcconnelli. Walcott [1908c, PI. I, fig. 2a] Obolus eeptalis. Obolus mcconnelli decipiens Walcott [new] Obolus mcconnelli decipiens. Obolus? major Matthew [1830, p. 155] Rustella? major. Obolus matinalis? Walcott [1905a, p. 325] Obolus matinalis?. Obolus membranaceous Walcott [1908d, p. 61] Obolus membranaceus. Obolus (?) meneghini Walcott [1901, p. 684] Obolus? meneghinii. Obolus mickwitzi Walcott [1898b, pp. 386-387] Obolus mick\vitzi. Obolus? minimus Barrande [1879b, PL XCV, figs, ii: 1-5] Acrotreta? minima. Obolus minimus Walcott [1905a, pp. 325-326] Obolus minimus. Obolus? minor Barrande [1868a, p. 105] ; Obolus? minor. Barrande [1868b, p. 693] Do. Obolus? monilifer Linnarsson [1871, pp. 9-10] Mickwitzia monilifera. Obolus? murrayi Billings [1865b, p. 362] Obolus? murrayi. Obolus namouna Walcott [1898b, p. 390] Obolus namouna. Obolus nundina Walcott [1905a, p. 326] Obolus nundina. Obolus obscurus Walcott [1905a, p. 326] Obolus obscurus. Obolus obtusus? Moberg and Segerberg [1906, p. 65] Obolus (Schmidtia) obtusus. Westergard [1909, p. 57] Do. Wiman [1902, p. 63] Do. Obolus? palliatus Barrande [1868a, pp. 104-105, fig. 64] Obolus? bavaricus. Barrande [1868a, pp. 104-105, fig. 65] Obolus? palliatus. Barrande [1868b, p. 693, fig. 64] Obolus? bavaricus. Barrande [1868b, p. 693, fig. 65] Obolus? palliatus. 74 CAMBRIAN BRACHIOPODA. Present reference. Obolua pandemia Walcott [1898b, p. 388] Obolus pandemia. Obolus panderi Mickw-itz [1896, pp. 149-151] Obolus panderi. Obolus parvus Walcott. [190Sd, pp. 61-62] Obolus parvus. Obolus pectenoides 'Whitfield [1875, p. 103] Dicellomus pectenoides. Obolus? pectenoides Whitfield [1880, pp. 338-339] Dicellomus pectenoides. Obolus pheres Walcott [19a5a, p. 328] .Obolus pheres. Obolus pristinus Matthew [1895a, pp. 121-122] Trematobolus pristinus. Matthew [1902c, p. 96] Do. Obolus? pulcher Hall and Clarke [lS92c, pp. 81 and 183] Botsfordia pulchra. Obolus pulcher Matthew [1889, p. 306] Do. Matthew [1890, pp. 151-155] Do. Obolus quenstedti Hall and Clarke [1892a, p. 243] Obolus apoUinis quenstedti. Hall and Clarke [1892b, p. 559] ._. Do. Hall and Clarke [1892c, p. 339] Do. Matthew [1903, p. 120] Do. Mickwitz [1892, p. 62] Do. Walcott [1898b, p. 385] Do. Obolus refulgens Matthew [1892, pp. 44-45] Obolus refulgena. Matthew [1902c, p. 96] Do. Obolus? refulgens MickT^dtz [1896, pp. 23-24] Do. Obolus rhea Walcott [1898b, pp. 387-388] Obolus rhea. Obolus? rokitzanensis Barrande [1879b, PL CXXVI] Obolus rokitzanensis. Obolus salteri Brogger [1882, pp. 44-45] Obolus (Broggeria) salteri. Obolus? salteri Dall [1870, p. 163] Do. Mickwitz [1896, p. 19] Do. Obolus schmidti Mickwitz [1896, pp. 152-154] Obolus schmidti. Obolus shensiensis Walcott [1905a, p. 327] Obolus shansiensis. Obolus siluricus Eichwald [1843a, pp. 7-8] Obolus (Mickwitzella)'8iluricus. Eichwald [1859, PI. XXXVII, figs. 6 and 7a-b] Do. Eichwald [I860, pp. 927-928] Do. Mickwitz [1892, p. 60] Do. Schmidt [1861, p. 218] Do. Schmidt [1881, p. 17] Do. Siemiradzki [1886, p. 672] Obolus (Acritis) antiquissimus. Obolus smithi M^alcott [1908d, pp. 62-63, PL VII, fig. 9a] Obolus smithi. Walcott [1908d, PL VII, fig. 9] Micromitra (Paterina) major. Obolus tetonensis Walcott [1901, p. 684] Obolus tetonensis. Walcott [1905a, p. 327] Do. Obolus tetonensis leda Walcott [1908d, p. 63] Obolus tetonensis leda. Obolus tetonensis ninus Walcott [1905a, p. 328] Obolus tetonensis ninus. Obolus torrentis Matthew [1902c, p. 94] Obolus? torrentis. Matthew [1903, p. 76] Do. Obolus triangularis Mickwitz [1896 , pp . 145-147] Obolus triangularis. Moberg and Segerberg [1906, p. 65] Do. Westerg^rd [1909, p. 56] Do. Obolus triangularis inornatus Mickwitz [1896, pp. 148-149] Do. Obolus triparilis Matthew [1902c, p. 94] Lingulella triparilis. Obolus volborthi Mickmtz [1896, pp. 155-157] Obolus volborthi. Obolus wortheni Walcott [1908d, pp. 63-64] Obolus wortheni. Obolus? zoppi Walcott [1901, pp. 684-685] Obolus? zoppi. Obolus sp. Kayser [1876, pp. 9-10] Obolus? sp. undt. Obolus? sp. Kjerulf [1873, p. 83, figs. 10 and 11] Obolella mobergi?. Obolus (?) sp. indet. Linnarsson [1876, p. 16] Obolus sp. undt. g. Obolus (Acritis) Mick\Wtz [1896, pp. 205-206] Obolus (Acritis). Walcott [1901, p. 683] Do. Walcott [1908e, PL XI, and pp. 142 and 144] Do. Obolus (Acritis) antiquissimus Mickwitz [1896, pp. 206-213] Obolus (Acritis) antiquissimus. Obolus (Acritis) antiquissimus ventrosus Mickwitz [1896, pp. 213-214]. . . . Do. Obolus (Acritis?) rugatus Walcott [1901, p. 694] Obolus (Acritis?) rugatus. Obolus (Botsfordia) Matthew [1891, p. 148] Botsfordia. Matthew [1892, p. 63] Do. Obolus (Botsfordia) pulcher Matthew [1891, p. 148] Botsfordia pulchra. Matthew [1892, pp. 62-63] Do. SYNONYMIC REFERENCES. 75 Present reference. Obolus (Botsfordia) pulcher Matthew [1902c, p. 95] Botsfordia pulchra. Obolus (Botsfordia) pulchra Matthew [1894, pp. 90-91] Do. Matthew [lS95a, pp. 115-121] Do. Obolus (Broggeria) Walcott [1902, p. 605] Obolus (Broggeria). Walcott [1908e, PI. XI, and pp. 142 and 144] Do. Obolus (Broggeria) salteri Moberg and Segerberg [1906, p. 64] Obolus (Broggeria) salteri. Walcott [1902, pp. 605-606] Do. Obolus (Broggeria) salteri var. ? Westergard [1909, p. 56] Do. Obolus (Eoobolus) Matthew [1903, pp. 135-136] Obolus (in part) and Lingulella (in part). Obolus (Eoobolus) discus Matthew [1903, pp. 138-139] Lingulella triparilis. Obolus (Eoobolus) triparilis Matthew [1903, pp. 136-137] Do. Obolus (Euobolus) Mickwitz [1896, pp. 129 and 133] Lingulella (in part) and Obolus (in part). Obolus (Fordinia) Walcott [1908d, pp. 64-65] Obolus (Fordinia). Walcott [1908e, PL XI, and pp. 142 and 144] Do. Obolus (Fordinia) gilberti Walcott [1908d, p. 65] Obolus (Fordinia) gilberti. Obolus (Fordinia) pertectus Walcott [1908d, pp. 65-66] Obolus (Fordinia) perfectus. Obolus (Leptembolon) Mickwitz [1896, p. 199] Lingulella (Leptembolon). Walcott [1908e, PL XI, and pp. 142 and 144] Do. Obolus (Leptembolon) lingulaeformis Mickwitz [1896, pp. 200-204] Lingulella (Leptembolon) linguteformis. Obolus (Leptembolon) lingulseformis solidus Mickwitz [1896, pp. 204-205] . . Do. Obolus (Lingulella) Walcott [1898b, pp. 390-392] Lingulella. Walcott [1901, p. 6S3] Do. Obolus (Lingulella) acutangulus Walcott [1898b, pp. 393 and 394, Pis. XXVII and XXVIII] Lingulella acutangula. Obolus (Lingulella) amplus Walcott [1898b, pp. 392 and 394, PI. XXVIII]. . . Lingulella ampla. Obolus (Lingulella) argutus Walcott [1898b, p. 396] Lingulella arguta. Obolus (Lingulella) atavus Walcott [1902, pp. 609-610] Lingulella atava. Obolus (Lingulella) auga Walcott [1898b, pp. 396-397] Lingulella auga. Obolus (Lingulella) bellulus Matthew [1903, p. 205] Lingulella bellula. Walcott [1898b, p. 398] Do. Obolus (Lingulella) bellus Matthew [1903, p. 204] Lingulella bella. Walcott [1898b, pp. 397-398] Do. Walcott [1901, pp. 685-687] Lingulella bella (in part), L. concinna (in part), and L. lens (in part). Lingulella) bicensis Walcott [1901, p. 688] Botsfordia cselata. Lingulella) bomemanni Walcott [1901, pp. 687-688] Lingulella bornemanni. Lingulella) canius Walcott [1902, pp. 610-611] Lingulella cania. Lingulella) celatus Walcott [1898b, PI. XXVI, figs. 1 and 2] Obolus (Schmidtia) celatus. Lingulella) chinensis Walcott [1905a, pp. 328-329] Obolus chinensis. Lingulella) chuarensis Walcott [1898b, p. 399] Obolus (Westonia) chuarensis. Lingulella) collicia Walcott [1902, p. 610] Lingulella collicia. Lingulella) concinnus Walcott [1902, pp. 608-609] Lingulella concinna. Lingulella) cuneolus Walcott [1899, p. 443] Lingulella cuneola. Lingulella) damesi Walcott [1905a, p. 329] Obolus damesi. (See Lingulella damesi, p. 489.) Lingulella) da-\dsii Walcott [1898b, pp. 394 and 395] Lingulella davisi. Lingulella) desideratus Walcott [1898b, pp. 399-400] Lingulella desiderata. Walcott [1899, pp. 445^46, PL LX, fig. 2]. . Do. Walcott [1899, pp. 445-446, PL LX, fig. 2a] .Obolus rotundatus. Lingulella) discoideus Walcott [1901, p. 673] Obolus discoideus. Lingulella) dubius Walcott [1898b, p. 401] Lingulella dubia. Lingulella) ella Walcott [1898b, PL XXVIII, figs. 5-8] Obolus (Westonia) ella. Lingulella) ellsi Walcott [1898b, p. 402] Lingulella ellsi. Lingulella) euglyphus Walcott [189Sb, pp. 402^03] Obolus (Westonia) euglyphus. Lingulella) fragilis Walcott [1898b, p. 404] : Obolus fragilis. Lingulella) franklinensis Walcott [1898b, pp. 404-405] Lingulella fi-anklinensis. Lingulella) fuchsi Walcott [1905a, p. 332] Lingulella fuchsi. Lingulella) gemmulus Walcott [1901, p. 673] Lingulella ferruginea. Lingulella) hayesi Walcott [1898b, pp. 405-406] Lingulella hayesi. Lingulella),helena Walcott [1898b, p. 406]. Lingulella helena. Lingulella) ino Walcott [1898b, pp. 406-407] Lingulella ino. Lingulella) isse Walcott [1905a, p. 330] Lingulella isse. Lingulella) lamborni minimus Walcott [1898b, p. 407] Obolus lamborni minimus. Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus 76 CAMBKIAN BRACHIOPODA- Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Obolus Present reference. Lingulella) lens Walcott [1902, pp. 606-607] Lingulella lens. Lingulella) leos Walcott [189Sb, pp. 407-408] Lingulella leos. Lingulella) lineolatus Walcott [1898b, pp. 408—409] Lingulella lineolata. Lingulella) linnarssoni Walcott [1901, p. 688] Lingulella linnarssoni. Lingulella) msera Walcott [1899, p. 443] Obolus msera. Lingulella) matinalis Walcott [1899, p. 443]1 Obolus matinalis. Lingulella) mosia osceola Walcott [1898b, p. 409] Lingulella mosia osceola. Lingulella) nanno Walcott [1898b, p. 409] Lingulella nanno. Lingulella) orus Walcott [1905a, p. 330] Lingulella ora. Lingulella) oweni Walcott [1898b, p. 410] Lingulella oweni. Lingulella) pelias Walcott [1905a, pp. 330-331] Obolus mcconnelli pelias. Lingulella) perattenuatus Walcott [1899, p. 443] Lingulella perattenuata. Lingulella) phaon Walcott [1898b, pp. 410^11] Lingulella phaon. Lingulella) pogonipensis Walcott [1898b, pp. 411^12] Lingulella pogonipensis. Lingulella) prindlei Walcott [1898b, p. 412] Obolus prindlei. Lingulella) punctatus Walcott [1898b, pp. 412-413] Lingulella punctata. Lingulella) quadrilateralis Walcott [1905a, p. 331] Lingulella quadrilateralis. Lingulella) randomensis Walcott [1901, pp. 688-689] Lingulella randomensis. Lingulella) rogersi Walcott [1898b, pp. 413^15] Obolus (Westonia) rogersi. Lingulella) rotundatus Walcott [1898b, p. 415] Obolus rotundatus. Lingulella) schmalenseei Walcott [1902, p. 605] Obolus schmalenseei. Lingulella) schucherti Walcott [1901, pp. 689-690] Lingulella schucherti. Lingulella) septalis Walcott [1905a, p. 331] Obolus septalis. Lingulella) siemiradzkii Walcott [1901, pp. 690-691] Liiigulella siemiradzkii. Lingulella) similis Walcott [1898b, pp. 415-416] Lingulella similis. Lingulella) sinoe Walcott [1898b, pp. 416-417] Obolus sinoe. Lingulella) spatulus Walcott [1902, p. 607] Lingulella (Lingulepis) spatula. Lingulella) tarpa Walcott [1898b, pp. 417-418] Lingulella tarpa. Lingulella) upis Walcott [1905a, pp. 331-332] .- Lingulella upis. Lingulella) wanniecki Walcott [1905a, p . 332] Lingulella wanniecki. Lingulella) welleri Walcott [1902, p. 608] Lingulella welleri. Lingulella) willisi Walcott [1898b, pp. 418-119] Obolus willisi. Lingulella) winona convexus Walcott [1901, p. 691] Lingulella winona convexa. Lingulella) zetus Walcott [1898b, p. 419] Obolus zetus. Lingulepis) Walcott [1899 , pp. 443^44] Lingulella (Lingulepis) . Walcott [1901, p. 683] Do. Lingulepis) acuminatus Walcott [1899, p. 443] Lingulella (Lingulepis) acuminata. Lingulepis) acuminatus meeki Walcott [1 899 , p. 444] Lingulella (Lingulepis) acuminata meeki. Lingulepis) eros Walcott [1905a, p. 333] Lingulella (Lingulepis) eros. Lingulepis) gregwa Walcott [1901, pp. 692-694] Lingulella atava (in part), L. tumidjr (in part), L. cania (in part), L. (Lin- gulepis) gregwa (in part), and L. (L.) exigua (in part). (Lingulepis) primus Walcott [1901 , p. 673] Lingulella prima. (Lingulepis) rowei Walcott [1905a, p. 334] lingulella (Lingulepis) rowei. (Lingulepis) sp. undt. Walcott [1906, pp. 567-568] Lingulella (Lingulepis ?) sp. undt. (Lingulobolus) Walcott [1901, p. 683] Obolus (Lingulobolus). Walcott [1908e, PL XI, and pp. 142 and 144] Do. (Lingulobolus) affinis Walcott [1898a, p. 327] Obolus (Lingulobolus) affinis. (Lingulobolus) spissus Walcott [1898a, p. 327] Obolus (Lingulobolus") spissus. (Lucina) antiquissimus Eichwald [1843b, pp. 142-144] Obolus (Acritis) antiquissimus. (Mickwitzella) Walcott [1908d, p. 70] Obolus (Mickwitzella). Walcott [1908e, PL XI, and pp. 142 and 144] Do. (Monobolina) refulgens Matthew [1902c, p. 98] Obolus refulgens. (PalKobolus) Walcott [1908e, PI. XI, and pp. 142 and 144] Obolus (Pateobolus). (Palffiobolus) lens Matthew [1903, pp. 144-146] Obolus (Pateobolus) bretonensis lens. (Pateobolus) lens longus Matthew [1903, pp. 146-147] Do. (Schmidtia) Mickwitz [1896, p. 158] Obolus (Schmidtia). Walcott [1901, p. 68.3] Do. Walcott [1908e, PL XI, and pp. 142 and 144] Do. (Schmidtia) acuminatus Mickwitz [1896, pp. 179-183] Obolus (Schmidtia) acuminatus. (Schmidtia) acuminatus alatus Mickwitz [1896, pp. 183-184] Do. SYNONYMIC REFERENCES. 77 Present reference. Obolus (Schmidtia) acuminatus humeratiis Mickwitz [1896, pp. 184-186]- . .Obolua (Schmidtia) acuminatus. Obolus (Schmidtia) acuminatus subtriangularis Mickwitz [1896, pp. 186- 187] Do. Obolus (Schmidtia) celatus Mickwitz [1896, pp. 159-163] Obolus (Schmidtia) celatus. Obolus (Schmidtia) celatus orbiculatus Mickwitz [1896, pp. 16.3-165] Do. Obolus (Schmidtia) celatus prascisus Mickwitz [1896, pp. 166-167] Do. Obolus (Schmidtia) crassus Mickwitz [1896, pp. 187-193] Obolus i Obolus (Schmidtia) crassus angulatus Mickwitz [1896, pp. 193-194] Do. Obolus (Schmidtia) obtusus Mickwitz [1896, pp. 167-171] Obolus i (Schmidtia) crassus. (Schmidtia) obtusus. Do Do Do Do Do Do Mickwitzella). Mickwitzella) siluricus. Mickwitzella). Westonia). Westonia) alandensis. Westonia) aurora. Westonia) balticus. Westonia) blackwelderi. Westonia) bottnicus. Westonia) chuarensis. Westonia) dartoni. Westonia) ella. Westonia) ella onaquiensis. Westonia) elongatus. Westonia) escasoni. Westonia) euglyphus. (Westonia) finlandensis. Obolus (Schmidtia) obtusus acutus Mickwitz [1896, pp. 172-173] Obolus (Schmidtia) obtusus ellipticus Mickwitz [1896, pp. 177-178]. . Obolus (Schmidtia) obtusus extenuatus Mickwitz [1896, pp. 178-179] Obolus (Schmidtia) obtusus latus Mickwitz [1896, pp. 174-175] Obolus (Schmidtia) obtusus longus Mickwitz [1896, pp. 171-172] Obolus (Schmidtia) obtusus minutus Mickwitz [1896, pp. 175-177]... Obolus (Thysanotos) Mickwitz [1896, pp. 194-195] Obolus Obolus (Thysanotos) siluricus Mickwitz [1896, pp. 195-199] Obolus Obolus (Thysanotus) Walcott [1901, p. 683] Obolus Obolus (Westonia) Walcott [1901, pp. 683 and 691] Obolus Walcott [] 908e, PI. XI, and pp. 142 and 144] Do, Obolus (Westonia) alandensis Walcott [1905a, p. 334] Obolus Obolus (Westonia) aurora Walcott [1901, p. 691] Obolus Obolus (Westonia) baltica Walcott [1905a, p. 334] Obolus Obolus (Westonia) blackwelderi Walcott [1905a, p. 335] Obolus Obolus (Westonia) bottnica Walcott [1905a, pp. 335-336] Obolus Obolus (Westonia) chuarensis Walcott [1901, p. 691] Obolus Obolus (Westonia) dartoni Walcott [1908d, p. 67] Obolus Obolus (Westonia) ella Walcott [1901, p. 691] Obolus Obolus (Westonia) ella onaquiensis Walcott [1908d , pp . 67-68] Obolus Obolus (Westonia) elongatus Walcott [1908d, p. 68] Obolus Obolus (Westonia) escasoni Walcott [1901, p. 691] Obolus Obolus (Westonia) euglyphus Walcott [1901, p. 691] Obolus Obolus (Westonia) finlandensis Walcott [1902, pp. 611-612] Olwlus Obolus (Westonia) iphis Walcott []90oa, p. 336] Obolus (Westonia) iphis. Obolus (Westonia?) lamellosus Walcott [1901, p. 691] Obolus (Westonia?) lamellosus. Obolus (Westonia) notchensis Walcott [1908d, p. 69] Obolus (Westonia) notchensis. Obolus (Westonia) rogersi Walcott [1901, p. 691] Obolus (Westonia) rogersi. Obolus (Westonia) stoneanus Walcott [1901, p. 691] Obolus (Westonia) stoneanus. Obolus (Westonia) themis Walcott [1905a, pp. 336-337] Obolus (Westonia) themis. Obolus (Westonia) wasatchensis Walcott [1908d, pp. 69-70] Obolus (Westonia) wasatehensis. Obolus (Westonia) wimani Walcott [1905a, p. 337] Obolus (Westonia) wimani. obscm-a [Billingsella], Walcott [1905a, p. 239] Billingsella obscura. obscurus [Obolus], Walcott [1905a, p. 326] Obolus obscurus. obtusus? [Obolus], Moberg and Segerberg [1906, p. 65] Obolus (Schmidtia) obtusus. Westergard [1909, p. 57] Wiman [1902, p. 63] obtusus [Obolus (Schmidtia)], Mickwitz [1896, pp. 167-171] obtusus acutus [Obolus (Schmidtia)], Mickwitz [1896, pp. 172-173] obtusus ellipticus [Obolus (Schmidtia)], Mickwitz [1896, pp. 177-178] obtusus extenuatus [Obolus (Schmidtia)], Mickwitz [1896, pp. 178-179] .. obtusus latus [Obolus (Schmidtia)], Mickwitz [1896, pp. 174-175] obtusus longus [Obolus (Schmidtia)], Mickwitz [1896, pp. 171-172] obtusus minutus [Obolus (Schmidtia)], Mickwitz [1896, pp. 175-177] occidens [Mickwitzia], Walcott [1908d, p. 54] Mickwitzia occidens. celandica [Acrotreta], Westergard [1909, p. 76] Acrotreta oslandica. onaquiensis [Obolus (Westonia) ella], Walcott [1908d, pp. 67-68] Obolus (Westonia) ella onaquiensis. ophirensis [Acrotreta], Walcott [1902, pp. 591-592] Acrotreta ophirensis. ophirensis [Acrotreta cf .], Walcott [new] Acrotreta cf . ophirensis. ophirensis [Iphidella pannula], Walcott [1905a, p. 306] Micromitra (Iphidella) pannula ophirensis. ophirensis descendens [Acrotreta], Walcott [1908d, p. 95] Acrotreta ophirensis descendens. ophirensis rugosus [Acrotreta], Walcott [1902, p. 592] Acrotreta ophirensis rugosa. ora [Micromitra (Paterina) stissingensis], Walcott [new] Micromitra (Paterina) stissingensis ora. Do. Do. Do. Do. Do. Do. Do. Do. Do. 78 CAMBRIAN BRACHIOPODA. Present reference. Orbicella Dall [1877, p. 50] Keyserlingia (in part). Dana [1846] Does not equal Keyserlingia. Hall and Clarke [1892a, p. 254] Keyserlingia. Hall and Clarke [1892b, p. 570] Do. d'Orbigny [1850, p. 20] Do. Orbicella bucbi Hall and Clarke. [1892a, p. 254] Keyserlingia buchi. d'Orbigny [1850, p. 20] Keyserlingia buchi (in part). Orbicula de Verneuil [1845, p. 288] Keyserlingia. Orbicula buchi de Verneuil [1845, pp. 288-289] Keyserlingia buchi. Orbicula caelata Hall [1847, p. 290] Botsfordia cselata. (Orbicula) cselata [Obolella], Ford [1871, p. 33] Do. Orbicula? crassa Hall [1847, p. 290] Obolella crassa. (Orbicula?) crassa [Obolella], Ford [1871, p. 33] Do. Orbicula prima Owen [1852, p. 583] Obolus matinalis. (Orbicula) primasva [Discina], de Verneuil and Barrande [1860, p. 532] Acrothele primaeva, orbiculatus [Obolus celatus], Moberg and Segerberg [1906, p. 65] Obolus (Schmidtia) celatus. Westergard [1909, p. 56] Do. Wiman [1902, p. 62] Do. orbiculatus [Obolus (Schmidtia) celatus], Mickwitz [1896, pp. 163-165] Do. Orbiculoidea Hall and Clarke [1892c, pp. 120-137] Orbiculoidea. d'Orbigny Do. Walcott [1908e, PI. XI, and pp. 142 and 147] Do. Orbiculoidea pileolus Hall and Clarke [1892c, p. 137] Orbiculoidea pileolus. | ordovicensis [Lingula?], Moberg and Segerberg [1906, p. 63] Lingulella lepis. orientalis [Billingsella], Hall and Clarke [1892c, p. 230] Billingsella orientalis. Walcott [190.5a, pp. 239-240] Do. orientalis [Iphidella labradorica], Walcott [1905a, pp. 305-306] Micromitra (Paterina) lab radorica orientalis. orientalis [Orthisina], Walcott [1886b, p. 120] Billingsella orientalis. ,; Walcott [1891a, p. 613] Do. Whitfield [1884, p. 144] Do. orientalis [Syntrophia], Walcott [1905a, p. 292] Huenella orientalis. orientalis [Yorkia?], Walcott [1906, pp. 569-570] Yorkia? orientalis. ornatella [Iphidea], Gronwall [1902, p. 40] Micromitra (Iphidella) ornatella. Hall and Clarke [1892c, pp. 97-98] Do. Linnarsson [1876, pp. 2.5-26] Do. ornatella [Iphidea cnf.?]. Hall and Clarke [1892c, PL IV, figs. 6 and 7]. . . .Micromitra (Paterina) superba. orta [Acrothyra signata], Matthew [1902b, pp. 385-386] Acrothyra signata orta. Matthew [1903, pp. 89-90] Do. orthia [Syntrophia], Walcott [1905b, pp. 11-12] Syntrophia orthia. Orthis von Buch (in part) [1841, p. 7] Obolus. Orthis barabuensis A. Winchell [1864, p. 228] Syntrophia barabuensis. Orthis bavarica Barrande [1868a, p. 99] Eoorthis bavarica. Barrande [1868b, p. 690] Do. Orthis billingsi Hartt [1868, pp. 644-645] Protorthis billingsi. Hartt [1878, pp. 644-645] Do. Hartt [1891, pp. 644-645] Do. Matthew [1886, p. 43] Do. Walcott [1884a, pp. 17-18] Do. Orthis christianise Brogger [1882, p. 48] Eoorthis christianise (in part) and E. daunus (in part). Gagel [1890, pp. 10 and 34] Eoorthis daunus. Kjerulf [1865, pp. 1 and 3] Eoorthis christianise. Pompeckj [1902, p. 7] Eoorthis daunus. Kernel^ [1881, p. 69] Do. Kernel^ [1885, p. 6] Do. Roemer [1885, pp. 36, 37, and 38] Do. Orthis coloradoensis Meek [1870, p. 425] Eoorthis desmopleura. Shumard [1860, p. 627] Billingsella coloradoensis. Orthis desmopleura Meek [1872; p. 295] Eoorthis desmopleura. Orthis? eurekensis Schuchert [1897, p. 286] Orusia? eurekensis. Orthis eurekensis Walcott [1884b, pp. 22-23] Do. Orthis exporecta Linnarsson [1876, pp. 12-13] Billingsella exporrecta. SYNONYMIC REFERENCES. 79 Present reference. Orthis exporrecta Kayser [1SS3, p. 35] Billingsella exporrecta. Wallerius [1895, p. 66] Do. Orthis hamburgensis Walcott [1884b, p. 73] Eoorthis desmopleura?. Orthis hicksi Kayser [1883, p. 35] Billingsella hicksi. Linnarsson [1876, pp. 13-14] Billingsella exporrecta rugosicostata. Orthis hicksii Davidson [1868, p. 314] Billingsella hicksi. Davidson [1869, p. 230] Do. Orthis? highlandensis Walcott [18S6b, pp. 119-120] Billingsella highlandensis. Walcott [1891a, p. 612] Do. Orthis kuthani Pompeckj [1896b, pp. 514-515] Nisusia (Jamesella) kuthani. Orthis lenticularis Brogger [1882, p. 48] Orusia lenticularis. Davidson [1868, p. 314] Do. Davidson [1869, pp. 230-232] Do. Matthew [1892, pp. 46-48] Do. Matthew [1903, pp. 213-216] ■ Do. Roemer [1876, PL II, figs. 4a-c] Do. Roemer [1S85, pp. 33-84] Do. Salter [lS66b, p. 339] Do. Salter and Etheridge [1881 , pp. 544-545] Do. Orthis lenticularis ? Kayser [1876, p. 9] Do. Orthis lenticularis atrj'poides Matthew [1892, p. 48] Orusia lenticularis atrypoides. Matthew [1903, p. 217] Do. Orthis lenticularis lyncioides Matthew [1892, p. 49] Orusia lenticularis lyncioides. Matthew [1903, p. 216] Do. Orthis lenticularis strophomenoides Matthew [1892, p. 49] Orusia lenticularis. Matthew [1903, p. 217] Do. Orthis lindstromi Linnarsson [1876, pp. 10-12] Billingsella lindstromi. Orthis linnarssoni Kayser [1883, p. 34] Eoorthis linnarssoni. Orthis newtonensis Weller [1903, pp. 113-114] Eoorthis newtonensis. Orthis (?) peculiaris Tate [1892, pp. 185-186] .Kutorgina peculiaris. Orthis pepina Hall [1863, pp. 134-135] Billingsella coloradoensis. Hall [1867, p. 113] Do. WTiitfield [1882, pp. 170-171] Do. Orthis perpasta Pompeckj [1896h, pp. 515-516] Nisusia (Jamesella) perpasta. Orthis perpasta macra Pompeckj [1896b, p. 516] Nisusia (Jamesella) perpasta macra. Orthis perpasta subquadrata Pompeckj [1896b, p. 516] Nisusia (Jamesella) perpasta subquadrata. Orthis primordialis Mallada [1875, p. 31] Eoorthis primordialis. de Verneuil and Barrande [1860, pp. 532-533] Do. Orthis quacoensis Matthew [1886, pp. 43-44] Protorthis quacoensis. Orthis? remnicha Walcott [1899, pp. 451-4.52, PI. LXI, figs. 3 and 3a; PL LXII, figs. 1, Ic-d] Eoorthis remnicha. The text includes both E. remnicha and E. iddingsi. Orthis remnicha Walcott [1899, pp. 451-452, PL LXII, figs, la-b] Eoorthis iddingsi. The text includes both E. iddingsi and E. remnicha. N. H. Winchell [1886, pp. 317-318] Eoorthis remnicha. Orthis romingeri Barrande [1848, p. 203] Billingsella romingeri. Barrande [1879a, PL LXII, figs, ii: 1-4] Do. Feistmantel Nisusia (Jamesella) kuthani. Jahn Do. Katzer Do. Krejci Do. Kusta Do. Novak Do. Pompeckj [1896b. pp. 513-514] Billingsella romingeri. Wentzel Nisusia (Jamesella) kuthani. Orthis salemensis Oehlert [1889, p. 1139] Billingsella salemensis. . Walcott [1887, pp. 190-191] Do. Walcott [1891a, pp. 612-613] Do. Orthis saltensis Kayser [1876, p. 8] Eoorthis saltensis. Kayser [1897, p. 280] '. Do. Orthis (?) sandbergi Walcott [1899, pp. 452-453] Otusia sandbergi. Orthis sandbergi N. H. Winchell [1886, p. 318] Do. 80 CAMBRIAN BRACHIOPODA. Present reference. Orthis (?) tatei Etheridge, jr. [1905, p. 249] Eoorthis tatei. Orthis ungula von Buch [1841, pp. 7-8] Obolus apollinis. Orthis warthi Waagen [1891, pp. 102-104] Wynnia warthi. Orthis sp. Kayser [1876, p. 9] Orusia lenticularis. Pompeckj [lS96a, p. 4] Eoorthis bavarica. Pompeckj [1896b, p. 514, PI. XV, fig. 6] Eoorthis sp. undt. a. Pompeckj [1896b, p. 514, PI. XV, fig. 7] Eoorthis sp. undt. b. Orthis (or Orthisina) sp. Etheridge [1905, p. 250] Huenella etheridgei. Orthis (Billingsella) pepina Sardeson [1896, p. 96] Billingsella coloradoensis. Orthis (Finkelnburgia) Walcott [1905a, pp. 277-278] Finkelnburgia. Orthis (Finkelnburgia) finkelnburgi Walcott [1905a, pp. 278-279] Finkelnburgia finkelnburgi. Orthis (Finkelnburgia) osceola Walcott [1905a, p. 279] Finkelnburgia osceola. Orthis (Finkelnburgia) osceola corrugata Walcott [1905a, p. 280] Finkelnburgia osceola corrugata. Orthis? (Orthisina?) pepina Hall [1883, PL XXXVII, figs. 16-19] Billingsella coloradoensis. Orthis (Orusia) Walcott [1905a, p. 273] Orusia. Orthis (Orusia?) eurekensis Walcott [1905a, p. 277] Orusia? eurekensis. Orthis (Orusia) lenticularis Walcott [190oa, pp. 273-276] Orusia lenticularis. Orthis (Orusia) lenticularis atrypoides Walcott [1905a, p. 276] Orusia lenticularis atrypoides. Orthis (Orusia) lenticularis lyncioides Walcott [1905a, p. 277] Orusia lenticularis lyncioides. Orthis (Plectorthis) Walcott [1905a, pp. 257-259] Eoorthis. Orthis (Plectorthis) agreste Walcott [1906, p. 570] Eoorthis agreste. Orthis (Plectorthis?) atava Walcott [1905a, pp. 259-260] Eoorthis atava. Orthis (Plectorthis) christianise Moberg and Segerberg [1906, p. 69] Eoorthis christianise (in part only). The reference includes also E. daunus and E. tullbergi. Walcott [1905a, pp. 260-261] Eoorthis christianise. Orthis (Plectorthis) daunus Mobei-g and Segerberg [1906, p. 69] Eoorthis daunus. Walcott [1905a, p. 261] Do. Orthis (Plectorthis) desmopleura Walcott [1905a, p. 261] Eoorthis desmopleura. Orthis (Plectorthis) desmopleura nympha Walcott [1905a, p. 262] Eoorthis desmopleura nympha. Orthis (Plectorthis) diablo Walcott [1905a, p. 262] Eoorthis? diablo. Orthis (Plectorthis) doris Walcott [] 905a, pp. 262-263] Eoorthis doris. Orthis (Plectorthis) hastingsensis Walcott [1905a, p. 263] Eoorthis hastingsensis. Orthis (Plectorthis) iddingsi Walcott [1905a, p. 264] Eoorthis iddingsi. Orthis (Plectorthis) indianola Walcott [1905a, pp. 264-265] Eoorthis indianola. Orthis (Plectorthis) johannensis Walcott [1905a, pp. 265-266] Eoorthis johannensis. Orthis (Plectorthis) kayseri Walcott [1905a, p. 266] Eoorthis kayseri. Orthis (Plectorthis) kichoueusis Walcott [1906, p. 570] Eoorthis kichouensis. Orthis (Plectorthis) linnarssoni Walcott [1905a, p. 266] Eoorthis linnarssoni. Orthis (Plectorthis) newtonensis Walcott [1905a, p. 267] Eoorthis newtonensis. Orthis (Plectorthis) pagoda Walcott [1905a, pp. 267-268] Eoorthis pagoda. Orthis (Plectorthis) papias Walcott [1905a, p. 268] Eoorthis papias. Orthis (Plectorthis) remnicha Walcott [1905a, pp. 268-269] Eoorthis remnicha. Orthis (Plectorthis) remnicha sulcata Walcott [1905a, p. 269] Eoorthis remnicha sulcata. Orthis (Plectorthis) remnicha texana Walcott [1905a, p. 270] Eoorthis remnicha texana. Orthis (Plectorthis) remnicha winfieldensis Walcott [1905a, p. 270] Eoorthis remnicha winfieldensis. Orthis (Plectorthis) retroflexa Walcott [1905a, pp. 270-271] Billingsella retroflexa. Orthis (Plectorthis) saltensis Walcott [1905a, p. 271] Eoorthis saltensis. Orthis (Plectorthis) tullbergi Moberg and Segerberg [1906, p. 69] Eoorthis tullbergi. Walcott [1905a, p. 271] Do. Orthis (Plectorthis) wicliitaensis Walcott [1905a, pp. 271-272] Eoorthis wichitaensis. Orthis (Plectorthis) wichitaensis Iseviusculus Walcott [1905a, p. 272] Eoorthis wichitaensis Iseviusculus. Orthis (Plectorthis) wimani Moberg and Segerberg [1906, p. 70] Eoorthis wimani. Walcott [1905a, p. 272] Do. Orthis (Plectorthis) sp. Walcott [1905a, pp. 272-273] Eoorthis sp. undt. a and b. Orthis (Plectorthis) sp. undt. Walcott [1906, p. 571] Eoorthis various sp. undt. Orthis (Protorthis) billingsi Wysogorski [1900, p. 227] Protorthis billingsi. Orthisina alberta Matthew [1902c, p. 109] Nisusia alberta. Walcott [1889c, p. 442] Do. Orthisina? billingsi Matthew [1891, p. 131] ' Protorthis billingsi. Orthisina compta Tate [1892, p. 185] Nisusia compta. SYNONYMIC REFERENCES. ■ 81 Present reference. Orthisina festinata Billings [1861b, p. 10] Nigusia festinata. Billings [1861c, p. 949] Do. Billings [1862b, p. 105] Do. Billings [1862e, p. 221] Do. Billings [1863, p. 284, figs. 289a-c] Do. Walcott [1886b, pp. 120-121] Do. Walcott [1891a, p. 613] Do. Orthisina (?) johannensis Matthew [1892, pp. 49-50] •. Eoorthis johannensis. Orthisina orientalis Walcott [1886b, p. 120] Billingsella orientalis. Walcott [lS91a, p. 613] Do. \\Tiitfield [1884, p. 144] Do. Orthisina pellico de Verneuil and Barrande [I860, pp. 535-536] Nisusia (Jamesella) pellico. (Orthisina?) pepina [Orthis?], Hall [1883, PI. XXXVII, figs. 16-19] Billingsella coloradoensis. Orthisina quacoensis Matthew [1891, p. 131] Protorthis quacoensis. Orthisina? transversa Walcott [1886b, p. 121] Nisusia festinata transversa. Walcott [1891a, p. 613] Do. Orthisina vaticina Mallada [1875, p. 32] Nisusia? vaticina. de Verneuil and Barrande [1860, pp. 533-535] Do. Orthisina [Orthis or] sp. Etheridge [1905, p. 250] Huenella etheridgei. orus [Obolus (Lingulella)], Walcott [1905a, p. 330] Lingulella ora. Orusia Walcott [1908e, PI. XI, and pp. 142 and 148] Orusia. (Orusia) [Orthis], Walcott [1905a, p. 273] Do. (Orusia?) eureliensis [Orthis], Walcott [1905a, p. 277] Orusia? eurekensis. (Orusia) lenticularis [Orthis], Walcott [1905a, pp. 273-276] Orusia lenticularis. (Orusia) lenticularis atrypoides [Orthis], Walcott [1905a, p. 276] Orusia lenticularis atrypoides. (Orusia) lenticularis lyncioides [Orthis], Walcott [1905a, p. 277] Orusia lenticularis lyncioides. osceola [Obolus (Lingulella) mosia], Walcott [1898b, p. 409] Lingulella mosia osceola. osceola [Orthis (Finkelnburgia)], Walcott [1905a, p. 279] Finkelnburgia osceola. osceola corrugata [Orthis (Finkelnburgia)], Walcott [1905a, p. 280] Finkelnburgia osceola corrugata. Otusia Walcott [1908e, PL XI, and pp. 142 and 148] Otusia. (Otusia) [Billingsella], Walcott [1905a, p. 246] Do. (Otusia) sandbergi [Billingsella], Walcott [1905a, pp. 246-247] Otusia sandbergi. Otusia utahensis Walcott [new] Otusia utahensis. ovalis [Acrotreta], Walcott [1902, p. 592] Acrotreta ovalis. ovalis [Lingulella ferruginea], Davidson [1868, p. 307] ■. . . Lingulella ferruginea. Hicks [Salter and Hicks, 1867, p. 341] Do. ovalis [Lingulella? inflata], Matthew [1895a, p. 127] Acrotreta inflata. ovata [Lingula], Emmons [1842, p. 105] Lingulella prima. McCoy [1846, p. 24] Lingula ovata, not Lingulella davisi. McCoy [1854, p. 254] Lingulella davisi (in part) and Lingula ovata (in part). oweni [Obolus (Lingulella)], Walcott [1898b, p. 410] Lingulella oweni. ovata [Ungula], Pander [1830, p. 59, PL XXVIII, figs. 6a-b] Obolus (Schmidtia) celatus. Pander [1830, pp. 59 and 154, PI. Ill, fig. 23] Obolus apollinis. P. pacifica [Acrotreta], Walcott [1905a, p. 301] Acrotreta pacifica. pagoda [Orthis (Plectorthis)], Walcott [1905a, pp. 267-268] Eoorthis pagoda. Palseobolus Matthew [1899b, pp. 201-202] Obolus (Palaeobolus). Matthew [1903, pp. 140-141] Do. (Palseobolus) [Obolus], Walcott [1908e, PI. XI, and pp. 142 and 144] Do. Palaeobolus bretonensis Matthew [ 1899b , p . 202] Obolus (Palseobolus) bretonensis . Matthew [1903, pp. 141-143] Do. (Palseobolus) lens [Obolus], Matthew [1903, pp. 144-146] Obolus (Palseobolus) bretonensis lens. (Palseobolus) lens longus [Obolus], Matthew [1903, pp. 146-147] Do. palliatus [Obolus?], Barrande [1868a, pp. 104-105, fig. 64] Obolus? bavaricus. Barrande [1868a, pp. 104-105, fig. 65] Obolus? palliatus. Barrande [1868b, p. 693, fig. 64] Obolus? bavaricus. Barrande [1868b, p. 693, fig. 65] Obolus? palliatus. pandemia [Obolus], Walcott [1898b, p. 388] Obolus pandemia. panderi [Acrothele], Walcott [new] Acrothele panderi. 62667°— VOL 51, ft 1—12 6 82 CAlVfflRIAN BRACHIOPODA. Present reference. panderi [Keyserlingia], Karpinsky [1887, p. 476] Helmersenia ladogensis. panderi [Obolus], Mickwitz [1896, pp. 149-151] Obolus panderi. pannula [Iphidea], Matthew [1902c, p. 110] Micromitra Qphidella) pannula. pannula [Iphidella], Walcott [1905a, p. 307] Do. pannula [Kutorgina], Pack [1906, p. 296] Do. Walcott [1886b, p. 105] Do. Walcott [1887, p. 190] Do. Walcott [1891a, p. 609] Do. pannula [Micromitra (Iphidella)], Walcott [190Sc, p. 244, PI, I, figs. 1, la-c]. Do.' pannula maladensis [Iphidella], Walcott [1905a, p. 306] Micromitra (Iphidella) pannula maladensis. pannula ophirensis [Iphidella], Walcott [190.5a, p. 306] Micromitra (Iphidella) pannula ophirensis. pannulus [Iphidea], Grabau and Shimer [1907, p. 201] Micromitra (Iphidella) pannula. Schuchert [1897, p. 234] Do. pannulus [Trematis], 'WTiite [1874, p. 6] Do. ■\\Tiite [1877, pp. 36-37] Do. papellata-prima [Acrotreta], Matthew [1902a, pp. 391-392] Acrothyra sera. papias [Orthis (Plectorthis)], Walcott [1905a, p. 268] Eoorthis papias. papillata [Acrotreta], Matthew [1902b, pp. 390-391] Acrothyra sera. Matthew [1903, p. 95] Do. papillata lata [Acrotreta], Matthew [1903, pp. 95-96] Do. papillata-prima [Acrotreta], Matthew [1903, pp. 73-74] Do. papillata var. [Acrotreta], Matthew [1902b, p. 391] -. Do. parvula [Acrotreta], Walcott [1902, p. 592] Acrotreta parvula. ' parvula [Obolella], Wallerius [1895, pp. 65-66] Do. parvus [Dicellomus], Walcott [1905a, pp. 315-316] Dicellomus par-\rus. parvus [Obolus], Walcott [1908d, pp. 61-62] Obolus parvus. Paterina Beecher [1891, p. 345] Micromitra (Paterina). Hall and Clarke [1892a, p. 247] Do. Hall and Clarke [1892b, p. 563] Do. Walcott [1897b, p. 708] Do. (Paterina) [Micromitra], Walcott [1908e, PI. XI, and pp. 142 and 143] Micromitra (Paterina). Paterina labradorica Beecher [1891, pp. 345-346] Micromitra (Paterina) labradoricaswanton- ensis. Hall and Clarke [1892a, p. 247] Do. (Paterina) labradorica var. undt. [Micromitra], Walcott [new] Micromitra (Paterina) labradorica var. undt. (Paterina) stissingensis ora [Micromitra], Walcott [new] Micromitra (Paterina) stissingensis ora. (Paterina) stuarti [Micromitra], Walcott [1908d, p. 58] Micromitra (Paterina) stuarti. (Paterina) wapta [Micromitra], Walcott [1908d, p. 59] Micromitra (Paterina) wapta. (Paterina) williardi [Micromitra], Walcott [1908d, p. 60] Micromitra (Paterina) williardi. Paterina (Micromitra) Schuchert [1905, p. 329] Micromitra. pealei [Iphidea], Walcott [1897b, pp. 712-713] Micromitra pealei. pectenoides [Dicellomus], Walcott [1901, p. 673] Dicellomus pectenoides. Walcott [1905a, p. 316] Do. pectenoides [Obolella], Schuchert [1897, p. 275] Do. pectenoides [Obolus], Whitfield [1875, p. 103] Do. pectenoides [Obolus?], 'tt'hitfield [1880, pp. 338-339] Do. peculiaris [Orthis (?)], Tate [1892, pp. 185-186] Kutorgina peculiaris. pelias [Obolus (Lingulella)], Walcott [1905a, pp. 330-331] Obolus mcconnelli pelias. pellico [Orthisina], de Vemeuil and Barrande [1860, pp. 535-536] Nisusia (Jamesella) pellico. pepina [Billingsella], Hall and Clarke [1892a, PI. VIII, figs. 1 and 2] Billingsella coloradoensis. Hall and Clarke [1892c, p. 230] Do. pepina [Orthis], Hall [1863, pp. 134-135] Do. Hall [1867, p. 113] Do. TMiitfield [1882, pp. 170-171] Do. pepina [Orthis (Billingsella)], Sardeson [1896, p. 96] Do. pepina [Orthis? (Orthisina?)], Hall [1883, PI. XXXVII, figs. 16-19] Do. perattenuatus [Lingulepis], ^Miitfield [1877, p. 9] Lingulella perattenuata. ■\Miitfield [1880, p. 337] Do. perattenuatus [Obolus (Lingulella)], Walcott [1899, p. 443] Do. perfectus [Obolus (Fordinia)], Walcott [1908d, pp. 65-66] Obolus (Fordinia) perfectus. perpasta [Nisusia (Jamesella)], Walcott [1905a, pp. 254-255] Nisusia (Jamesella) perpasta. perpasta [Orthis], Pompeckj [1896b, pp. 51.5-516] Do. perpasta macra [Nisusia (Jamesella)], Walcott [1905a, p. 255] Nisusia (Jamesella) perpasta macra. perpasta macra [Orthis], Pompeckj [1896b, p. 516] Do. SYNONYMIC REFERENCES. 83 Present reference. perpasta subquadrata [Nisusia (Jamesella)], Walcott [1905a, p. 255] Nisusia (Jamesella) perpasta subquadrata. perpasta subquadrata [Orthis], Pompeckj [1896b, p. 516] Do. perugata [KutorgiBa], Walcott [1905a, p. 310] Kutorgina pemgata. petalon [Lingula], Bomemann [1891, p. 438] Obelus? meneghinii. Davidson [1868, p. 308] Does not equal Obolus? meneghinii. Davidson [1871, p. 337] Do. phaon [Obelus (Lingulella)], Walcott [1898b, pp. 410-411] Lingulella phaon. pheres [Obolus], Walcott [1905a, p. 328] Obolus pheres. Philhedra von Huene [1899a, pp. 146-147] Philhedra. von Huene [1899b, pp. 216-218 and 297-298] Do.- Koken [1889, pp. 465 and 467] Do. Walcott [1908e, PL XI, and pp. 142 and 147] Do. Philhedra? columbiana von Huene [1899b, pp. 216 and 298] Philhedra Columbiana. Philhedra columbiana Walcott [1908c, PL I, figs. 5 and 5a] Do. phillipsi [Kutorgina cingulata], Matley [1902, pp. 145-147] Micromitra (Paterina) phillipsi. phillipsi [Obolella?], Davidson [1866, pp. 62-63] Do. phillipsi [Obolella], Holl [1865, p. 102] Do. Phillips [1871, p. 68] Do. phillipsi [Obolellus?], Roemer [1876, PL XI, figs. 6a-d] Do. phillipsia [Obolella], Dall [1877, p. 41] Do. pileolus [Discina], Davidson [1868, pp. 312-313] Orbiculoidea pileolus. Davidson [1871, p. 344] Do. (Hicks MS.) Salter [1866a, p. 285] Do. pileolus? [Discina], Hicks [1871, PI. XV, figs. 12 and 12a] Stenotheca pileolus, a gastropod. pileolus [Orbiculoidea], Hall and Clarke [1892c, p. 137] Orbiculoidea pileolus. pinnaformis [Lingula], Owen [1852, p. 583] Lingulella (Lingulepis) acuminata. pinnaformis [Lingulems], Hall [1863, pp. 129-130, PL VI, figs. 12 and 13]. Obolus matinalis. Hall [1863, pp. 129-130, PL VI, figs. 14-16] Lingulella (Lingulepis) acuminata. Hall [1867, p. 107, PL I, figs. 12 and 13] Obolus matinalis. Hall [1867, p. 107, PL I, figs. 14-16] Lingulella (Lingulepis) acuminata. •^Tiitfield [1880, p. 335] Do. Whitfield [1882, pp. 169-170] Do. pinnseformis [Lingula], Hall [1862, p. 435, and fig. 3, p. 21] Do. pinniformis [Lingulepis], Dwight [1886, p. 208] Do. Grabau and Shimer [1907, p. 193] Do. Hall and Clarke [1892a, p. 232] Do. Hall and Clarke [1892b, p. 548] Do. Hall and Clarke [1892c, p. 60] Do. Meek and Hayden [1865, pp. 2-3] Do. Schuchert [1897, p. 260] Do. plana [Ungula], Pander [18.30, pp. 59 and 163] Obolus apollinis. plana or convexa [Ungula], Pander [1830, p. 163] Do. plana retroflexa [Clitambonites (Gonambonites)], Matthew [1895b, p. 267]. . Billingsella retroflexa. planus retroflexus [Clitambonites], Schuchert [1897, p. 184] Do. ^ Platyceras etheridgei Tate [1892, p. 184] Micromitra (Paterina) etheridgei. Plectorthis Grabau and Shimer [1907, pp. 250 and 251] Eoorthis (in part) and Plectorthis (in part). Llall and Clarke [1892c, pp. 194-195] Plectorthis, not Eoorthis. (Plectorthis) [Orthis], Walcott [1905a, pp. 257-259] Eoorthis. (Plectorthis) agreste [Orthis], Walcott [1906, p. 570] Eoorthis agreste. (Plectorthis?) atava [Orthis], Walcott [1905a, pp. 259-260] Eoorthis atava. (Plectorthis) christianise [Orthis], Moberg and Segerberg [1906, p. 69] Eoorthis christiania3 (in part only). The reference includes also E. daunus and E. tullbergi. Walcott [1905a, pp. 260-261] Eoorthis christianiK. (Plectorthis) daunus [Orthis], Moberg and Segerberg [1906, p. 69] Eoorthis daunus. Walcott [1905a, p. 261] Do. (Plectorthis) desmopleura [Orthis], Walcott [1905a, p. 261] Eoorthis desmopleura. (Plectorthis) desmopleura nympha [Orthis], Walcott [1905a, p. 262] Eoorthis desmopleura nympha. (Plectorthis) diablo [Orthis], Walcott [1905a, p. 262] Eoorthis? diablo. (Plectorthis) doris [Orthis], Walcott [1905a, pp. 262-263] Eoorthis doris. (Plectorthis) hastingsensis [Orthis], Walcott [1905a, p. 263] Eoorthis hastingsensis. (Plectorthis) iddingsi [Orthis], Walcott [1905a, p. 264] Eoorthis iddingsi. 84 CAMBRIAN BRACHIOPODA. Present reference. Plectorthis indianola Grabau and Shimer [1907, pp. 251-252] Eoorthis indianola. (Plectorthis) indianola [Orthis], Walcott [1905a, pp. 264-265] Do. (Plectorthis) johannensis [Orthis], Walcott [1905a, pp. 265-266] Eoorthis johannensis. (Plectorthis) kayseri [Orthis], Walcott [1905a, p. 266] Eoorthis kayseri. (Plectorthis) kichoueusis [Orthis], Walcott [1906, p. 570] Eoorthis kichouensis. (Plectorthis) linnarssoni [Orthis], Walcott [1905a, p. 266] Eoorthis linnarssoni. (Plectorthis) newtonensis [Orthis], Walcott [1905a, p. 267] Eoorthis newtonensis. (Plectorthis) pagoda [Orthis], Walcott [1905a, pp. 267-268] Eoorthis pagoda. (Plectorthis) papias [Orthis], Walcott [1905a, p. 268] Eoorthis papias. Plectorthis remnicha Grabau and Shimer [1907, p. 252] Eoorthis remnicha. (Plectorthis) remnicha [Orthis], Walcott [1905a, pp. 268-269] Do. (Plectorthis) remnicha sulcata [Orthis], Walcott [1905a, p. 269] Eoorthis remnicha sulcata. (Plectorthis) remnicha texana [Orthis], Walcott [1905a, p. 270] Eoorthis remnicha texana. (Plectorthis) remnicha winfieldensis [Orthis], Walcott [1905a, p. 270] Eoorthis remnicha winfieldensis. (Plectorthis) retroflexa [Orthis], Walcott [1905a, pp. 270-271] Billingsella retroflexa. (Plectorthis) saltensis [Orthis], Walcott [1905a', p. 271] Eoorthis saltensis. (Plectorthis) tullbergi [Orthis], Moberg and Segerberg [1906, p. 69] Eoorthis tullbergi. Walcott [1905a, p. 271] Do. (Plectorthis) wichitaensis [Orthis], Walcott [1905a, pp. 271-272] Eoorthis wichitaensis. (Plectorthis) wichitaensis laeviusculus [Orthis], Walcott [1905a, p. 272] Eoorthis wichitaensis Iseviusculus. (Plectorthis) wimani [Orthis], Moberg and Segerberg [1906, p. 70] Eoorthis wimani. Walcott [1905a, p. 272] Do. (Plectorthis) sp. [Orthis], Walcott [1905a, pp. 272-273] Eoorthis sp. undt. a and b. (Plectorthis) sp. undt. [Orthis], Walcott [1906, p. 571] Eoorthis various sp. undt. pKcatella [Billingsella], Walcott [1905a, pp. 240-241] Billingsella plicatella. pogonipensis [Obolus (Lingulella)], Walcott [1898b, pp. 411-412] Lingulella pogonipensis. polita [Aulonotreta], Kutorga [1848, pp. 279-282] Obolus apollinis (in part), O. apollinis ingricus (in part), and 0. (Mickwitzella) siluricus (in part). polita [Dicellomus], Hall [1873, p. 246] Dicellomus politus. polita [Lingala], Hall [1861, p. 24] Do. poHta [Lingula?], Hall [1862, pp. 21 and 435] Do. polita [Lingula], Whitfield [1862, p. 136] Do. polita [Obolella], Billings [1862c, p. 421] Do. polita [Obolella?], Hall [1863, pp. 133-134] Do. Hall [1867, pp. 112-113] Do. polita [Obolella], Hall and Clarke [1892c, pp. 72 and 73] Do. Walcott [1886b, p. Ill] Do. Whitfield [1880, pp. 339-340] Do. politus [Dicellomus], Grabau and Shimer [1907, pp. 189-190] Do. Walcott [1899, pp. 443 and 446] Do. Walcott [1905a, pp. 313 and 316-318] Do. Polytcechia? montanensis Walcott [1905a, pp. 295-296] ' Clarkella? montanensis. praecisus [Obolus (Schmidtia) celatus], Mickwitz [1896, pp. 166-167] Obolus (Schmidtia) celatus. pretiosa [Acrothele], Walcott [1898b, p. 402] Acrothele pretiosa. pretiosa [BiUingsia], Ford [1886a, p. 467] Do. pretiosa [Elkania], Ford [1886b, p. 325] Do. pretiosa [Linnarssonia], Grabau and Shimer [1907, p. 200] - . . . Either Acrotreta sagittalis or Acrothele pretiosa. (See p. 652.) Hall and Clarke [1892c, p. 70] Acrotreta sagittalis. Schuchert [1897, p. 262] Acrotreta sagittalis (in part) and Acro- thele pretiosa (in part). Walcott [1901, p. 673] Acrothele pretiosa. pretiosa [Linnarssonia cf .], Hall [1890, p. 55] Acrotreta sagittalis. pretiosa [Mickwitzia], Walcott [1908d, pp. 54-55] Mickwitzia pretiosa. pretiosa [Obolella], Billings [1862d, pp. 68-69] Acrothele pretiosa. Billings [1863, p. 230] Do. Chapman [1863, p. 191] Do, Chapman [1864, p. 163] Do. pretiosa [Obolella?], Walcott [1886b, p. Ill] Do. pretiosa [Obolella (Linnarssonia)], Dawson [1890, pp. 53-54] Acrotreta sagittalis. prima [Acrothele matthewi], Hall and Clarke [1892a, PI. Ill, fig. 27] Acrothele prima. Hall and Clarke [1892c, PI. Ill, fig. 25] Do. SYNONYMIC REFERENCES. 85 Present reference. prima [Acrothele matthewi], Matthew [1886, p. 41] Acrothele prima. Matthew [1895a, PI. V, figs. 7a-b] Do. Matthew [1902b, pp. 397 and 402] Do. Matthew [1903, p. 104] Do. prima [Acrothyra proavia], Matthew [1901b, p. 303] Acrothyra proavia. Matthew [1902b, p. 389] Do. Matthew [1903, pp. 58, 86, and 93] Do. prima [Acrothyra signata], Matthew [1902b, pp. 382-383] Acrothyra signata prima. Matthew [1903, p. 73] Do. prima [Acrotreta papillata], Matthew [1902b, pp. 391-392] Acrothyra sera. prima [Acrotreta papillata], Matthew [1903, pp. 73-74] Do. prima [Lingula], Billings [1856, p. 34] Lingulella (Lingulepis) acuminata. Emmons [1855, p. 202] . . . Lingulella prima. Hall [1847, p. 3] Do. Hall [1851, p. 204] Lingulella (Lingulepis) acuminata. Hayden [1862, p. 73] Probably equals Lingulella (Lingalepis) acuminata. Owen [1851, p. 170] Lingulella (Lingulepis) acuminata. Rogers [1861, p. 390] Obolus (Westonia) rogersi. prima [Lingulella?], Hall and Clarke [1892c, p. 69] Lingulella prima. prima [Lingulepis], Grabau and Shimer [1907, p. 193] Lingulella (Lingulepis) acuminata. Meek and Hayden [1865, p. 3] Dicellomus politus. Miller [1877, p. 115] Lingulella prima. Schuchert [1897, p. 260] Lingulella prima (in part). prima [Meekina], Walcott [1905a, p. 313] Linnarssonella tennesseensis. prima [Obolella], Whitfield [1884, pp. 142-143] Lingulella prima. prima [Orbicula], Owen [1852, p. 583] Lingulella (Lingulepis) acuminata. Owen [1852, p. 583] Obolus matinalis. primasea [Acrotreta], Walcott [1902, p. 593] Acrotreta primKva. primasva [Acrothele], Pompeckj [1896b, p. 603] Acrothele primseva. primseva [Discina (Orbicula)], de Verneuil and Barrande [1860, p. 532] Do. primseva [Lingulella], Davidson [1883, p. 208] Lingulella? primseva. Hicks [1871, p. 401] Do. Hicks [1881, p. 297] Do. Salter and Etheridge [1881, p. 538] Do. primordialis [Orthis], Mallada [1875, p. 31] Eoorthia primordialis. de Verneuil and Barrande [1860, pp. 532-533] Do. primordialis [Syntrophia], Hall and Clarke [1893b, p. 218] Syntrophia primordialis. Walcott [1905a, p. 292] Do. primordialis [Triplecia?], Hall and Clarke [1892c, p. 270] Do. primordialis [Triplesia], 'WTiitfield [1878, p. 51] Do. ■^Tiitfield [1882, p. 172] Do. primordialis argia [Syntrophia], Walcott [1905a, p. 293] Syntrophia primordialis argia. primus [Obolus lens], Matthew [1902c, pp. 94-95] Obolus (Palceobolus) bretonensis lens. primus [Obolus (Lingulepis)], Walcott [1901, p. 673] Lingulella prima. prindlei [Obolus (Lingulella)], Walcott [1898b, p. 412] Obolus prindlei. priscus [Schizambon], Matthew [1901a, pp. 277-278] Schizambon priscus. Matthew [1903, pp. 187-189] Do. pristinua [Obolus], Matthew [1895a, pp . 121-122] Trematobolus pristinus. Matthew [1902c, p. 96] Do. proavia [Acrothyra], Matthew [1902b, pp. 386-388] Acrothyra proavia. Matthew [1903, pp. 53-55] Do. proavia [Acrotreta], Matthew [1899b, p. 203] Do. proavia crassa [Acrothyra], Matthew [1902b, pp. 389-390] Do. Matthew [1903, p. 94] Do. proavia prima [Acrothjnra], Matthew [1901b, p. 303] Do. Matthew [1902b, p. 389] Do. Matthew [1903, pp. 58, 86, and 93] Do. producta [Lingula?], Moberg and Segerberg [1906, p. 63] Lingulella lepis. proles [Acrothele], Matthew [1902b, pp. 400-401] Acrothele proles. Matthew [1903, pp. 60 and 102-103] Do. prolificus [Dicellomus], Walcott [1908d, p. 77] Dicellomus prolificus. prospectensis [Iphidea], Schuchert [1897, p. 234] Micromitra (Paterina) prospectensis. prospectensis [Iphidella], Walcott [1905a, p. 307] Do. 86 CAMBRIAN BRACHIOPODA. Present reference. prospectensis [Kutorgina], Walcott [1884b, p. 19] Micromitra (Paterina) prospectensis. Walcott [18S6b, pp. 106-107] Do. Walcott [1891a, p. 610] Do. Protorhyncha? antiquata Schuchert [1897, p. 334] Swantonia antiquata. Protorhyncha? minor Schuchert [1897, p. 334] Obolella minor. Protorthis Grabau and Shimer [1907, p. 211] Protorthis!. Hall and Clai-ke [lS92a, pp. 273-274] Do. Hall and Clarke [1892b, pp. 589-590] Do. Hall and Clarke [1892c, pp. 231-233] Do. Walcott [1905a, pp. 280-281] - - Do. Walcott [1908e, PI. XI, and pp. 142 and 147] Do. Protorthis billingsi Hall and Clarke [1892a, p. 274] Protorthis billingsi. Hall and Clarke [1S92C, pp. 219 and 232] Do. Walcott [1905a, pp. 281-282] Do. {Protorthis) billingsi [Orthis], Wysogorski [1900, p. 227] Do. Protorthis? eurekensis Hall and Clarke [1892c, p. 232] Orusia? eurekensis. Protorthis helena Walcott [1905a, p. 282] Protorthis helena. Protorthis? hunnebergensis Moberg and Segerberg [1906, pp. 70-71] Protorthis? hunnebergensis. Protorthis lavis Walcott [1905a, p. 283] Protorthis Ifevis. Protorthis latourensis Walcott [1905a, pp. 282-283] Protorthis latourensis. Protorthis nautes Walcott [1905a, pp. 283-284] Nisusia (Jamesella) nautes. Protorthis? nunnebergensis Walcott [1905a, p. 284] Protorthis? hunnebergensis. Protorthis quacoensis Hall and Clarke [1892c, p. 232] Protorthis quacoensis. , Walcott [1905a, pp. 284^285] Do. Protorthis spencei Walcott [1905a, p. 285] Nisusia (Jamesella) spencei. Protorthis wingi Walcott [1905a, p. 286] Protorthis wingi. Protorthis sp. undt. Walcott [1905a, p. 286] Protorthis sp. undt. Protorthis (BiUingsella) billingsi Grabau and Shimer [1907, p. 211] Protorthis billingsi. Protorthis (Loperia) Walcott [1905a, p. 287] Protorthis (Loperia). Walcott [1908e, PL XI, and pp. 142 and 147] Do. Protorthis (Loperia) dougaldensis Walcott [1905a, pp. 287-288] Protorthis (Loperia) dugaldensis. Protosiphon Matthew [1897a, pp. 68-69] Trematobolus. Matthew [1898a, pp. 129-130] Do. Protosiphon kempanum Matthew [1897a, pp. 70-71] Trematobolus kempanum. Matthew [1898a, p. 131] Do. pulcher [Obelus?], Hall and Clarke [1892c, pp. 81 and 183] Botsfordia pulchra. pulcher [Obolus], Matthew [1889, p. 306] Do. Matthew [1890, pp. 151-155] Do. pulcher [Obolus (Botsfordia)], Matthew [1891, p. 148] Do. Matthew [1892, pp. 62-63] Do. Matthew [1902c, p. 95] Do. pulchra [Obolus (Botsfordia)l, Matthew [1894, pp. 90-91] Do. Matthew [1895a, pp. 115-121] Do. pumila [Lingulepis], Matthew [1903, p. 75] Lingulella (Lingulepis) pumila. pumpellyi [BiUingsella], Walcott [1905a, p. 242] BiUingsella pumpellyi. punctatus [Obolus (Lingulella)], Walcott [1898b, pp. 412-413] Lingulella punctata. pusilla [Kutorgina cingulata], Gronwall [1902, p. 40] Micromitra pusilla. Linnarsson [1876, p. 25] Do. Matley [1902, pp. 146-147] Do. puteis [Acrothele avia], Matthew [1902b, p. 398] Acrothele avia puteis. Matthew [1903, p. 100] Do. pygm^a [Lingula], Davidson [1866, p. 53] Lingulella (Lingulepis?) pygm»a. Matley [1902, p. 141] Do. Phillips [1871, p. 68] Do. Salter [1865, p. 102] Do. pyxidicula [Acrotreta], A\1iite [1874, p. 9] Acrotreta pyxidicula. White [1877, pp. 53-54] Do. Q. quacoensis [BiUingsella], Schuchert [1897, p. 159] Protorthis quacoensis. quacoensis [Orthis], Matthew [1886, pp. 43^4] Do. quacoensis [Orthisina], Matthew [1891, p. 131] Do. quacoensis [Protorthis], Hall and Clarke [1892c, p. 232] Do. Walcott [1905a, pp. 284-285] Do. SYNONYMIC KEFERENCES. 87 Present reference. quadrilateralis [Obolus (Lingulella)], Walcott [1905a, p. 331] Lingulella quadrilateralis. quadrilineata [Acrothele], Pompeckj [lS96b, p. 511] Acrothele quadrilineata. Quebecia Walcott [1905a, p. 320] Quebecia. Walcott [1908e, PI. XI, and pp. 142 and 145] Do. Quebecia circe Walcott [1905a, pp. 320-321] Quebecia circe. quenstedti [Obolus], Hall and Clarke [1892a, p. 243] Obolus apollinis quenstedti. Hall and Clarke [1892b, p. 559] Do. Hall and Clarke [1892c, p. 339] Do. Matthew [1903, p. 120] Do. Mickwitz [1892, p. 62] Do. Walcott [1898b, p. 385] Do. quenstedti [Obolus apollinis], Mickwitz [1896, pp. 143-145] Do. R. radula [Lingulella], Matthew [1891, pp. 147-148] Lingulella radula. radula aspera [Lingulella], Matthew [1903, pp. 204-205] Do. Rafinesquina? atava Schuchert [1897, p. 338] Eoorthis atava. randomensis [Obolus (Lingulella)], Walcott [1901, pp. 688-689] Lingulella randomensis. rara [Nisusia], Walcott [1908d, p. 97] Nisusia rara. rarus [Acrothele], Walcott [1905a, pp. 303-304] Acrothele rara. recurva [Acrotreta], Kutorga [1848, pp. 277-278] Volborthia recurva. recurva [Volborthia], Hall and Clarke [1892a, figs. 261 and 262, p. 249] Do. Hall and Clarke [1892b, figs. 261 and 262, p. 565] Do. Hall and Clarke [1892c, pp. 95-96] Do. von Moller [1874, pp. 449^52] Do. (Redlichella) [Acrothele], Walcott [1908d, pp. 89-90] Acrothele (Redlichella). Walcott [1908e, PL XI, and pp. 142 and 146].... Do. refulgens [Monobolina], Matthew [1903, pp. 210-213] Obolus refulgens. refulgena [Obolus], Matthew [1892, pp. 44-45] Do. Matthew [1902c, p. 96] Do. refulgens [Obolus?], Mickwitz [1896, pp. 23-24] Do. refulgens [Obolus (Monobolina)], Matthew [1902c, p. 98] Do. remnicha [Orthis?], Walcott [1899, pp. 451-^52, PL LXI, figs. 3 and 3a; PL LXII, figs. 1, Ic-d] Eoorthis remnicha. The text includes both E. remnicha and E. iddingsi. Walcott [1899, pp. 451^52, PL LXII, figs, la-b] Eoorthis iddingsi. The text includes both E. iddingsi and E. remnicha. remnicha [Orthis], N. H. Winchell [1886, pp. 317-3181 Eoorthis remnicha. remnicha [Orthis (Plectorthis)], Walcott [1905a, pp. 268-269] Do. remnicha [Plectorthis], Grabau and Shimer [1907, p. 252] Do. remnicha sulcata [Orthis (Plectorthis)], Walcott [1905a, p. 269] Eoorthis remnicha sulcata. remnicha texana [Orthis (Plectorthis)], Walcott [1905a, p. 270] Eoorthis remnicha texana. remnicha winfieldensis [Orthis (Plectorthis)], Walcott [1905a, p. 270] Eoorthis remnicha winfieldensis. retroflexa [Billingsella], Matthew [1903, pp. 148-151] Billingsella retroflexa. retroflexa [Clitambonites (Gonambonites) plana], Matthew [1895b, p. 267].. Do. retroflexa [Orthis (Plectorthis)], Walcott [1905a, pp. 270-271] Do. retroflexus [Clitambonites planus], Schuchert [1897, p. 184] Do. rhea [Obolus], Walcott [1898b, pp. 387-388] Obolus rhea. richthofeni [Billingsella], Walcott [1905a, pp. 242-243] Billingsella richthofeni. roberti [Lingulella], Matthew [1895b, pp. 256-257]..- Lingulella (Lingulepis) roberti. roberti [Lingulepis], Matthew [1903, p. 132] Do. robusta [Lingulepis gregwa], Matthew [1903, pp. 57 and 131] Lingulella (Lingulepis) gregwa robusta. rogersi [Lingulella], Grabau [1900, pp. 624-625] Obolus (Westonia) rogersi. rogersi [Obolus (Lingulella)], Walcott [1898b, pp. 413-415] Do. rogersi [Obolus (Westonia)], Walcott [1901, p. 691] Do. rokitzanensis [Obolus?], Barrande [1879b, PL CXXVI] Obolus rokitzanensis. romingeri [Billingsella], Walcott [1905a, pp. 243-244] Billingsella romingeri. romingeri [Orthis], Barrande [1848, p. 203] Do. Barrande [1879a, PL LXII, figs. II : 1-4] Do. Feistmantel Nisusia (Jamesella) kuthani. Jahn Do. Katzer Do. Krejci Do. 88 OM'IBRIAN BRACHIOPODA. Present reference. romingeri [Orthis], Kusta Nlsusia (Jameeella) kuthani. Novak Do. Pompeckj [1896b, pp. 513-514] Billingsella romingsri. Wentzel Nisusia (Jamesella) kuthani. rotunda [Lingulepis], Matthew [1903, p. 199] Lingulella rotunda. rotunda [Ungula], Pander [1830, pp. 59 and 163] Obolus apoUinis. rotundata [Syntrophia], Walcott [1905a, pp. 293-294] Syntrophia rotundata. rotundatus [Obolus (Lingulella)], Walcott [1898b, p. 415] Obolus rotundatus. roualti [Lingula], Bornemann [1891, p. 439] Kutorgina sardiniaensis. rowei [Obolus (Lingulepis)], Walcott [1905a, p. 334] Lingulella (Lingulepis) rowei. rudis [Acrotreta], Walcott [1908d, pp. 95-96] Acrotreta rudis. rugatus [Obolus (Acritis?)], Walcott [1901, p. 694] Obolus (Acritis?) rugatus. rugosa [Schizopholis], Hall and Clarke [1892a, p. 248] Schizopholis rugosa. Hall and Clarke [1892b, p. 564] Do. Hall and Clarke [1892c, p. 95] Do. Waagen [1885, pp. 753-754] Do. Waagen[1891, PI. 11, figs. 12-14] Do. rugosicostata [Billingsella exporrecta], Walcott [1905a, p. 236] Billingsella exporrecta rugosicostata. rugosus [Acrotreta ophirensis], Walcott [1902, p. 592] Acrotreta ophirensis rugosa. Rustella Walcott [1905a, p. 311] Rustella. Walcott [1908e, PI. XI, and pp. 142 and 143] Do. Rustella edsoni Walcott [1905a, pp. 311-312] Rustella edsoni. S. sabrinse [Acrotreta (?)], Matley [1902, p. 143] Acrotreta sabrinae. sabrinse [Metoptoma], Callaway [1874, p. 196] Do. sabriuK [Obolella], Callaway [1877, p. 669] Do. Davidson [1883, p. 211] Do. Hall and Clarke [1892c, p. 103] Do. sabrinse malvernensis [Acrotreta (?)], Matley [1902, pp. 143-144] Do. saffordi [Billingsella], Walcott [1905a, p. 244] Wimanella saffordi. sagittalis [Acrotreta of.], Walcott [new] Acrotreta of. sagittalis. sagittalis [Linnarssonia], Freeh [1897, PI. lA, fig. 3a] Acrotreta sagittalis. Hall and Clarke [1892c, p. 108] Do. Walcott [1885a, p. 115] Do. Walcott [1889c, p. 442] Acrotreta depressa. Walcott [1891a, PI. LXVIII, figs. 2a-d] Acrotreta sagittalis. sagittalis [Obolella], Brogger [1882, p. 45] . Do. Davidson [1868, pp. 309-310] Do. Davidson [1871, pp. 339-340] Do. Davidson [1883, p. 211] Do. Linnarsson [1876, pp. 19-20] Do. Linnarsson [1879, pp. 27-28] Do. Salter [1866a, p. 285] Do. sagittalis [Obolella cf .], Wiman [1902, p. 66] Do. sagittalis [Obolella (Acrotreta?)], Moberg and Segerberg [1906, p. 64] Do. sagittalis belti [Obolella], Davidson [1871, desc. o£ PL L, figs. 15-17] Acrotreta belti. sagittalis magna [Acrotreta], Walcott [1902,,pp. 595-596] Acrotreta sagittalis magna. sagittalis taconica [Acrotreta], Walcott [1902, pp. 596-597] Acrotreta sagittalis taconica. sagittalis taconica [Linnarssonia], Walcott [1889b, p. 36] Do. Walcott [1891a, pp. 610-611] Do. sagittalis transversa [Linnarssonia], Freeh [1897, PL lA, fig. 3b] Acrotreta sagittalis transversa, Walcott [1891a, desc. of PL LXVIII, figs. 2a, 2c-d] Do. salemensis [Billingsella], Walcott [1905a, p. 245] Billingsella salemensis. salemensis [Orthis], Oehlert [1889, p. 1139] Do. Walcott [1887, pp. 190-191] Do. Walcott [1891a, pp. 612-613] Do. saltensis [Orthis], Kayser [1876, p. 8] , Eoorthis saltensis. Kayser [1897, p. 280] 1 Do. saltensis [Orthis (Plectorthis)], Walcott [1905a, p. 271] Do. salteri [Obolella (?)], Davidson [1868, p. 311] Obolus (Broggeria) salteri. salteri [Obolella], Holl [1865, p. 102] Do. SYNONYMIC REFERENCES. 89 Present reference. salteri [Obolella (?)], Matley [1902, pp. 139-140] Obolus (Broggeria) ealteri. ealteri [Obolella], Phillips [1871, p. 68] Do. salteri? [Obolella], Davidson [1866, pp. 61-62] Do. salteri [Obolus], Brogger [1882, pp. 44-45] Do. salteri [Obolus?],, Dall [1870, p. 163] Do. Mickwitz [1896, p. 19] Do. salteri [Obolus (Broggeria)], Moberg and Segerberg [1906, p. 64] Do. Walcott [1902, pp. 605-606] Do. salteri var.? [Obolus (Broggeria)], Westerga.rd [1909, p. 56] Do. sandbergi [Billingsella (Otusia)], Walcott [1905a, pp. 246-247] Otusia sandbergi. sandbergi [Orthis (?)], Walcott [1899, pp. 452^53] Do. sandbergi [Orthis], N. H. Winchell [1886, p. 318] Do. saidiniaensis [Kutorgina], Walcott [1901, p. 695] Kutorgina sardiniaensis. Walcott [1905a, p. 311] Do. scabrinae [Obolella?], Walcott [1884b, PL I, fig. Ic] Acrotreta sabrinse. Schizambon Hall and Clarke [1892a, pp. 253-254] Schizambon. Hall and Clarke [1892b, pp. 569-570] Do. Hall and Clarke [1892c, pp. 113-117] Do. Walcott [1884b, pp. 69-70] Do. Walcott [1908e, PI. XI, and pp. 142 and 146] Do. Winchell and Schuchert [1895, p. 360] Do. Schizambon ? esthonia Walcott [new] Schizambon ? esthonia. Schizambon manitouensis Walcott [new] Schizambon manitouensis. Schizambon priscus Matthew [1901a, pp. 277-278] Schizambon priscus. Matthew [1903, pp. 187-189] Do. Schizambon typicalis Hall and Clarke [1892a, p. 253] Schizambon typicalis. Hall and Clarke [1892c, pp. 114, 116, and 117] Do. Walcott [1884b, pp. 70-71] Do. Schizambonia Oehlert [1887, p. 1266] Schizambon. Schizopholis Hall and Clarke [1892a, p. 248] .• Schizopholis. Hall and Clarke [1892b, p. 564] Do. Hall and Clarke [1892c, p. 94] Do. Oehlert [1887, p. 1267] Do. Waagen [1885a, p. 752] Do. Walcott [1908e, PL XI, and pp. 142 and 145] Do. Schizopholis rugosa Hall and Clarke [1892a, p. 248] Schizopholis rugosa. Hall and Clarke [1892b, p. 564] Do. Hall and Clarke [1892c, p. 95] Do. Waagen [1885a, pp. 753-754] Do. Waagen [1891, PL II, figs. 12-14] Do. schmalenseei [Acrotreta], Walcott [1902, pp. 597-598] Acrotreta schmalenseei. schmalenseei [Obolus (Lingulella)], Walcott [1902, p. 605] Obolus schmalenseei. schmidti [Obolus], Mickwitz [1896, pp. 152-154] Obolus schmidti. Schmidtia Balsamo-Crivelli [1863] A genus of the Porifera. Schmidtia Dall [1877, p. 62] Obolus (Schmidtia). Hall and Clarke [1892a, p. 244] Do. Hall and Clarke [1892b, p. 560] Do. Hall and Clarke [1892c, p. 83] Do. Oehlert [1867, p. 1261] Do. '. Volborth [1869, pp. 208-209] Do. Zittel [1880, p. 665] Dicellomus (in part) and Obolus (Schmidtia) (in part). (Schmidtia) [Obolus], Mickwitz [1896, p. 158] Obolus (Schmidtia). Walcott [1901, p. 683] Do. Walcott [1908e, PL XI, and pp. 142 and 144] ... Do. (Schmidtia) acuminatus [Obolus], Mickwitz [1896, pp. 179-183] Obolus (Schmidtia) acuminatus. (Schmidtia) acuminatus alatus [Obolus], Mickwitz [1896, pp. 183-184] Do. (Schmidtia) acuminatus humeratua [Obolus], Mickwitz [1896, pp. 184-186] Do. (Schmidtia) acuminatus sub triangularis [Obolus], Mickwitz [1896, pp. 186- 187] Do. Schmidtia celata Hall and Clarke [1892a, p. 244] Obolus (Schmidtia) celatus. Hall and Clarke [1892b, p. 560] Do. Hall and Clarke [1892c, p. 83] Do. Volborth [1869, pp. 209-212] Do. 90 CMIBRIAN BRACHIOPODA. Present reference. (Schmidtia) celatus [Obolus], Mickwitz [1896, pp. 159-163] Obolus (Schmidtia) celatus. (Schmidtia) celatus orbiculatus [Obolus], Mickwitz [1896, pp. 163-165] Do. (Schmidtia) celatus prsecisus [Obolus], Mickwitz [1896, pp. 166-167] Do. Schmidtia?? complexus Mickwitz [1896, pp. 19-20] Obolus compiexus. (Schmidtia) crassus [Obolus], Mickwitz [1896, pp. 187-193] Obolus (Schmidtia) crassus. (Schmidtia) crassus angulatus [Obolus], Mickwitz [1896, pp. 193-194] Do. (Schmidtia) obtusus [Obolus], Mickwitz [1896, pp. 167-171] Obolus (Schmidtia) obtusus. (Schmidtia) obtusus acutus [Obolus], Mickwitz [1896, pp. 172-173] Do. (Schmidtia) obtusus ellipticus [Obolus], Mickmtz [1896, pp. 177-178] Do. (Schmidtia) obtusus extenuatus [Obolus], Mickwitz [1896, pp. 178-179]... . Do. (Schmidtia) obtusus latus [Obolus], Mickwitz [1896, pp. 174-17.5] Do. (Schmidtia) obtusus longus [Obolus], Mickwitz [1896, pp. 171-172] Do. (Schmidtia) obtusus minutus [Obolus], Mickwitz [1896, pp. 175-177] Do. schucherti [Obolus (Llngulella )], Walcott [1901, pp. 689-690] Lingulella schucherti. Schuchertina Walcott [1905a, p. 323] Schuchertina. Walcott [1908e, PI. XI, and pp. 142 and 145] Do. Schuchertina cambria Walcott [1905a, pp. 323-324] Schuchertina cambria. scotica [Micromitra], Walcott [new] Micromitra scotica. sculpta [Aulonotreta], Dall [1877, p. 16] Obolus (Acritis) antiquissimus. Kutorga [1848, pp. 282-283] Do. sculptilis [Iphidea (??)], Meek [1873, p. 479] Micromitra sculptilis. sculptilis [Iphidea], Schuchert [1897, p. 235] Do. Walcott [1899, pp. 447^48] Do. 1 sculptilis [Iphidella], Walcott [1905a, p. 308] Do. sculptilis [Kutorgina], Walcott [1884b, p. 20] Do. sculptilis endlichi [Micromitra], Walcott [1908d , p . 56] Micromitra sculptilis endlichi. seebachi [Acrotreta], Moberg and Segerberg [1906, pp. 66-67] Acrotreta seebachi. Walcott [1902, pp. 598-599] Do. selwyni [Lingulella], Matthew [1895b, pp. 255-256] Obolus selwyni. Matthew [1903, pp. 62-63] Do. Matthew [1903, pp. 116-123] Do. septaUs [Obolus (Lingulella)], Walcott [1905a, p. 331] Obolus septalis. sequens [Lingulella (Lingulepis) acuminata], Walcott [1908d, p. 72] Lingulella (Lingulepis) acuminata sequena. sera [Acrothyra (signata)], Matthew [1902b, pp. 383-384] Acrothyra sera. sera [Acrothyra signata], Matthew [1903, p. 56] Do. Matthew [1903, pp. 87-88] Do. shantungensis [Acrotreta], Walcott [1905a, pp. 301-302] .■ Acrotreta shantungensis. shelbyensis [Wimanella], Walcott [1908d, p. 100] Wimanella shelbyensis. shensiensis [Obolus], Walcott [190.5a, p. 327] Obolus shansiensis. siemiradzkii [Obolus (Lingulella)], Walcott [1901, pp. 690-691] Lingulella siemiradzkii. signalis [Acrotreta], Walcott [1902, p. 599] Acrotreta signalis. signata [Acrothyra], Matthew [1902b, pp. 381-382] Acrothyra signata. Matthew [1903, p. 87] Do. signata [Lingula?], Barrande [1868a, p. 103] Lingulella signata. Barrande [1868b, p. 692] Do. signata orta [Acrothyra], Matthew [1902b, pp. 385-386] Acrothyra signata orta. Matthew [1903, pp. 89-90] Do. signata prima [Acrothyra], Matthew [1902b, pp. 382-383] Acrothyra signata prima. Matthew [1903, p. 73] Do. (signata) sera [Acrothyra], Matthew [1902b, pp. 383-384] Acrothyra sera. signata sera [Acrothj-ra], Matthew [1903, p. 56] Do. Matthew [1903, pp. 87-88] Do. signata tarda [Acrothyra], Matthew [1902b, pp. 384-38.5].....' Do. Matthew [1903, p. 89] Do. siluricus [Obolus], Eichwald [1843a, pp. 7-8] Obolus (Mickwitzella) siluricus. Eichwald [1859, PI. XXXVII, figs. 6 and 7a-b] Do. Eichwald [I860, pp. 927-928] Do. Mickwitz [1892, p. 60] Do. Schmidt [1861, p. 218] Do. Schmidt [1881, p. 17] Do. Siemiradzki [1886, p. 672] Obolus (Acritis) antiquissimus. siluricus [Obolus (Thysanotos)], Mickwitz [1896, pp. 195-199] Obolus (Mickwitzella) siluricus. similis [Obolus (Lingulella)], Walcott [1898b, pp. 41.5^16] Lingulella similis. simplex, [Lingula], Barrande [1879b, PI. CIV, figs, vi: 1-4] Lingulella? simplex. SYNONYMIC REFERENCES. 91 Present reference. ■simplex [Wimanella], Walcott [1908d, p. 101] Wimanella simplex. since [Obolus (Lingulella'l], Walcott [189Sb, pp. 416^17] Obolus sinoe. Siphonotreta Davidson [1853, pp. 131-133] Siphonotreta. Davidson [1866, p. 75] Do. Davidson [1877, pp. 13-16] Do. Davidson [1883, pp. 217-219] Do. Eichwald [1860, p. 915] Do. Hall and Clarke [1892a, pp. 252-253] Do. Hall and Clarke [1892b, pp. 568-569] Do. Hall and Clarke [1892c, pp. 110-113] Do. Jeremejew [1856, pp. 73 and 80] Helmersenia. Kutorga [1848, pp. 261-263] Siphonotreta. Morris [1849, pp. 315-320]..... Do. Morris [1850, pp. 57-58] Do. Oehlert [1887, p. 1265] Do. Quen-stedt [1871, pp. 673-674] Do. Seebach [1865, p. 341] Do. de Vemeuil [1845, p. 286] Do. Walcott [1908e, PL XI, and pp. 142 and 146] Do. Winchell and Schuchert [1895, p. 358] Do. Zittel [1880, pp. 665-666] Do. Siphonotreta ? dubia Walcott [new] 1 Siphonotreta ? dubia. Siphonotreta ladogensis Jeremejew [1856, pp. 73 and 80] Helmersenia ladogensis. Siphonotreta unguiculata Davidson [1853, PI. IX, figs. 261-265, 269, and 270] Siphonotreta unguiculata. Davidson [1877, pp. 14 and 15] Do. Eichwald [1860, pp. 915-916] Do. Gagel [1890, p. 23] Do. Hall and Clarke [1892a, p. 253] Do. Hall and Clarke [1892c, p. Ill] Do. Kutorga [1848, pp. 264 and 284] Do. Quenstedt [1871, p. 674] Do. Quenstedt [1885, p. 755] Do. Schmidt [1861, p. 218] Do. de Verneuil [1845, pp. 286-287] Do. Walcott [1884b, p. 16] Do. Zittel [1880, p. 666] Do. Siphonotreta unguiculata var. a Kutorga [1848, p. 284] Do. Siphonotreta unguiculata var. /3 Kutorga [1848, pp. 264-265] Do. Siphonotreta unguiculata var. ;- elongata Kutorga [1848, p. 265] Do. Siphonotreta verrucosa Davidson [1853, PL IX, figs. 267 and 268] Siphonotreta verrucosa. Eichwald [1860, pp. 916-917] Do. Gagel [1890, p. 22] Do. Kutorga [1848, pp. 266-267] Do. Morris [1849, PL VII, figs. 2a-d] Do. Quenstedt [1871, p. 674] Do. Quenstedt [1885, p. 7.5.5].. Do. Schmidt [1861, p. 218] Do. de Verneuil [1845, p. 287] Do. -sipo [Acrotreta], Matthew [1902b, pp. 406^07] Acrotreta bisecta. Matthew [1903, pp. 185-186] Do. smithi [Obolus], Walcott [1908d, pp. 62-63, PL VII, fig. 9a] Obolus smithi. Walcott [1908d, PL VII, fig. 9] Micromitra (Paterina) major. ■ socialis [Acrotreta], Gronwall [1902, p. 39] Either Acrotreta schmalenseei or A. socialis. (Seep. 712.) Llnnarsson [1876, pp. 16-18] Acrotreta schmalenseei. Linnarsson [1877, p. 374] Either Acrotreta schmalenseei or A. socialis. (See p. 712.) von Seebach [1865, p. 341] Acrotreta socialis. Walcott [1902, pp. 599-600] Do. Wallerius [1895, p. 66] Acrotreta schmalenseei. .socialis [Acrotreta cf.], Brogger [1882, pp. 46-47, PI. X, figs. 2, 2a-b] Acrotreta carinata. Brogger [1882, pp. 46-47, PL X, figs. 3 and 4] Not referred in this monograph. Matley [1902, pp. 144-145] Acrotreta sabrinse. 92 CAMBRIAN BRACHIOPODA. Present reference. socialis [Acrotreta cf.], Matthew [1902b, pp. 392-394] Acrotreta sp. undt., not A. socialis. Matthew [1903, pp. 183-185] Do. solidus [Obolus (Leptembolon) linguleeformis], Mickwitz [1896, pp. 204- 205] Lingulella (Leptembolon) lingulseformis. spatulus [Obolus (Lingulella)], Walcott [1902, p. 607] Lingulella (Lingulepis) spatula. spencei [Protorthis], Walcott [1905a, p. 285] Nisusia (Jamesella) spencei. Sphaerobolus Matthew [1895b, p. 263] Obolus (Lingulobolus) . Sphserobolus spissus Grabau [1900, pp. 622-623] Obolus (Lingulobolus) spissus. Matthew [1895b, pp. 263-266] Do. spinosa [Acrotreta], Walcott [1905a, p . 302] Acrotreta epinosa. Spirifera? lenticularis von Buch [1834, p . 48] Orusia lenticularis. epissa [Lingulella?], Billings [1872b, pp. 468^69] Obolus (Lingulobolus) spissus. Billings [1874, pp. 67-68] Do. Billings [1882, p. 15] Do. spissus [Obolus (Lingulobolus)], Walcott [1898a, p. 327] Do. spissus [Sphserobolus], Grabau [1900, pp. 622-623] Do. Matthew [1895b, pp. 263-266] Do. spurri [Acrothele], Walcott [1908d, pp. 86-87] Acrothele spurri. squama [Davidsonella], Waagen [1885, pp. 766-767] Neobolus warthi. squamosa [?Lingula], Da\'idson [1866, p . 41] Lingulella (Lingulepis?) squamosa. squamosa [Lingula], Holl [1865, p. 102] Do. starri [Lingulella], Matthew [1891, pp. 146-147] Lingulella (Lingulepis) starri. starri [Lingulepis], Matthew [1903, p. 195] Do. I • starri exigua [Lingulepis], Matthew [1903, pp. 197-198] Lingulella (Lingulepis) exigua. starri minor [Lingulella], Matthew [1892, pp. 58-59] Lingulella minor. starri var. [Lingulepis], Matthew [1903, pp. 193-197] Lingulella (Lingulepis) exigua. stissingensis [Iphidea], Schuchert [1897, p. 234] Micromitra (Paterina) stissingensis. stissingensis [Iphidella], Walcott [1905a, p. 308] Do. stissingensis [Kutorgina], Dwight [1889, pp. 145-147] Do. Dwight [1891, p. 105] Do. stissingensis ora [Micromitra (Paterina)], Walcott [new] Micromitra (Paterina) stissingensis ora. stoneana [Lingulella], Hall and Clarke [1892c, PI. II, figs. 9-11] Obolus (Westonia) stoneanus. Weller [1903, p. 112] Do. Whitfield [1882, pp. 344-345] Do. stoneanus [Obolus (Westonia)], Walcott [1901, p. 691] Do. striata [Billirigsella], Walcott [1905a, p. 245] : Billingsella striata. Strophomena atava Matthew [1893b, pp. 102-103] Eoorthis atava. Strophomena? atava Moberg and Segerberg [1906, PI. II, figs. 7, 7a-b] Do. Strophomena (Eostrophomena) Walcott [1905a, p. 256] Eostrophomena. Strophomena (Eostrophomena) elegantula Walcott [1905a, pp. 256-257] ..Eostrophomena elegantula. Strophomena (Eostrophomena) walcotti Moberg and Segerberg [1906, p. 71]. Do. strophomenoides [Orthis lenticularis], Matthew [1892, p. 49] Orusia lenticularis. Matthew [1903, p. 217] Do. stuarti [Micromitra (Paterina)], Walcott [1908d, p. 58] Micromitra (Paterina) stuarti. subconica [Acrotreta], Davidson [1853, PI. IX, figs. 271-275] Acrotreta subconica. Kutorga [1848, p. 275] Do. Meek [1873, p. 463] Acrotreta attenuata (in part), A. attenuata var. (in part), and A. idahoensis (in part). Quenstedt [1885, p. 755] Acrotreta subconica. vonSeebach [1865, p. 341] Do. Walcott [1902, pp. 600-601] Do. subquadrata [Nisusia (Jamesella)'perpasta], Walcott [1905a, p. 255] Nisusia (Jamesella) perpasta subquadrata. subquadrata [Orthis perpasta], Pompeckj [1896b, p. 516] Do. subsidua [Acrothele], Beecher [1891, PL XVII, fig. 12] Acrothele subsidua. Grabau and Shimer [1907, p. 200] Do. Hall and Clarke [1892c, pp. 100 and 103] Do. Matthew [1902c, p. 110] Do. Matthew [1903, p. 103] Acrothele spurri.' Walcott [1886b, pp. 108-109, PI. IX, figs. 4a-c] Acrothele subsidua. The paragraph on page 109 includes reference to this spe- cies and to Acrothele spurri. Walcott [1886b, p. 109, PI. IX, fig. 4] Acrothele spurri. The paragraph on page 109 includes reference to this species and to Acrothele subsidua. SYNONYMIC REFERENCES. 93 Present reference. subsidua [Acrothele], Walcott [1891a, p. 608, PI. LXX, fig. 1] Acrothele spurri. The text includes refer- ence to this species and to Acrothele sub- sidua. Walcott [1891a, pp. 608-609, PI. LXX, figs. la-c].... Acrothele subsidua. The text includes reference to this species and to Acrothele spurri. White [1880, p. 47] Acrothele subsidua. subsidua [Acrotreta?], White [1874, p. 6] Do. A^Tiite [1877, pp. 34-36] Do. subsidua hera [Acrothele], Walcott [190Sd, p. 87] Acrothele subsidua hera. subsidua leevis [Acrothele], Walcott [new] Acrothele subsidua Isevis. subtriangularis[Obolus (Schmidtia) acuminatus], Mickwitz [1896, pp. 186- 187] Obolus (Schmidtia) acuminatus. sulcata [Acrotreta idahoensis], Walcott [1902, p. 588] Acrotreta idahoensis sulcata. sulcata [Crania], Eichwald [1829, p. 274] Siphonotreta unguiculata. sulcata [Orthis (Plectorthis) remnicha], Walcott [1905a, p. 269] Eoorthis remnicha sulcata. sulcatus [Discinopsis], Walcott [1906, pp. 568-569] Discinopsis? sulcatus. superba [Iphidea], Walcott [1897b, p. 711] Micromitra (Paterina) superba. swantonensis [Iphidea], Grabau and Shimer [1907, p. 201] Micromitra (Paterina) labradorica swanton- ensis. swantonensis [Iphidea labradorica], Schuchert [1897, p. 234] Do. ' swantonensis [Iphidella labradorica], Walcott [1905a, p. 307] Do. swantonensis [Kutorgina labradorica], Walcott [1890b, p. 36] Do. Walcott [1891a, p. 609] Do. Swantonia Walcott [1905a, p. 296] Swantonia. Walcott [1908e, PI. XI, and pp. 142 and 148] Do. Swantonia antiquata Walcott [1905a, pp. 296-297] Swantonia antiquata. Swantonia weeksi Walcott [1905a, p. 297] Swantonia weeksi. Syntrophia Grabau and Shimer [1907, p. 270] Syntrophia. Hall and Clarke [1892c, p. 270] Do. Hall and Clarke [1893b, pp. 216-218] Do. Hall and Clarke [1894a, p. 836] Do. Walcott [1905a, pp. 288-289] Syntrophia (in part) and Huenella (in part). Walcott [1908e, PI. XI, and pp. 142 and 148] Syntrophia. Syntrophia abnormis Walcott [1905a, pp. 289-290] Huenella abnormis. Syntrophia alata Walcott [1905a, p. 290] Syntrophia alata. Syntrophia barabuensis Hall and Clarke [1893b, p. 216] Syntrophia barabuensis. Walcott [190.5a, pp. 290-291] Do. Syntrophia billingsi Walcott [1905a, pp. 291-292] Huenella billingsi. Syntrophia calcifera Grabau and Shimer [1907, p. 271] Syntrophia nundina. Syntrophia? calcifera Hall and Clarke [1893b, p. 218] Syntrophia calcifera. Syntrophia Cambria Walcott [1908d, pp. 106-107] Syntrophia cambria. Syntrophia campbelli Walcott [1908d, pp. 107-108] Syntrophia campbelli. Syntrophia lateralis Hall and Clarke [1892c, p. 270] Syntrophia lateralis. Hall and Clarke [1893b, p. 217] Do. Hall [1894a, p. 837] Do. Syntrophia nundina Walcott [1905a, p. 292] Syntrophia nundina. Syntrophia orientalis Walcott [190.5a, p. 292] Huenella orientalis. Syntrophia orthia Walcott [190.5b, pp. 11-12] Syntrophia orthia. Syntrophia primordialis Hall and Clarke [1893b, p. 218] Syntrophia primordiali j. Walcott [1905a, p. 292] Do. Syntrophia primordialis argia Walcott [1905a, p. 293] Syntrophia primordialis argia. Syntrophia rotundata Walcott [1905a, pp . 293-294] Syntrophia rotundata. Syntrophia texana Walcott [1905a, p. 294] Huenella texana. Syntrophia texana Iseviusculus Walcott [1905a, pp. 294-295] Huenella texana lisviusculus. Syntrophia? unxia Walcott [1908d, pp. 108-109] Syntrophia? unxia, T. taconica [Acrotreta sagittalis], Walcott [1902, pp. 596-597] Acrotreta sagittalis taconica. . taconica [Linnarssonia], Oehlert [1889, p. 1138]- Do. Walcott [1887, pp. 189-190] Do. taconica [Linnarssonia sagittalis], Walcott [1889b, p. 36] Do. Walcott [iggia, pp. 610-611] Do. tarda [Acrothyra signata], Matthew [1902b, pp. 384-385] Acrothyra sera. 94 CAMBRIAN BRACHIOPODA. Present reference. tarda [Acrothyiu signata], Matthew [1903, p. 89] Acrothyra sera. tarpa [Obolus ( Lingulella)], Walcott [189Sb, pp. 417-418] Lingulella tarpa. tatei [Orthis (?)], Etheridge, jr. [1905, p. 249] Eoorthis tatei. Tellinomya McCoy [1854,''p. 274] Lingulella. Tellinomya lingulaj-comes McCoy [ISola, p. 56] Lingulella davisi. Salter Does not equal Lingulella davisi. Tellinomya lingulicomes McCoy [18.54, p. 274] Lingulella davisi. tennesseensis [Linnarssonella], Walcott [1902, pp. 604-605] Linnarssonella tennesseensis. Terebratula Eichwald [1840, p. 138 (24)] Siphonotreta (in part). Eichwald [1843b, p. 145] Siphonotreta. Terebratula unguiculata Eichwald [1840, pp. 138-140 (24-26)] Siphonotreta unguiculata. Eichwald [1S42, p. 145] Do. Terebratula verrucosa Eichwald [1840, pp. 140-141 (26-27)] Siphonotreta verrucosa. tetonensis [Acrotreta microscopica], Walcott [1902, p. 590] Acrotreta microscopica tetonensis. tetonensis [Obolus], Walcott [1901, p. 684] Obolus tetonensis. Walcott [1905a, p. 327] ■ - Do. tetonensis leda [Obolus], Walcott [1908d, p. 63] Obolus tetonensis leda. tetonensis ninus [Obolus], Walcott [1905a, p. 328] Obolus tetonensis ninus. texana [Lingulella], Walcott [1908d, p. 71] Lingulella texana. texana [Orthis (Plectorthis) remnicha], Walcott [1905a, p. 270] Eoorthis remnicha texana. texana [Syntrophia], Walcott [1905a, p. 294] Huenella texana. texana teviusculus [Svntrophia], Walcott [1905a, pp. 294-295] Ht:enella texana laeviusculus. themis [Obolus ( Westonia)], Walcott [1905a, pp. 336-337] Obolus (Westonia) themis. thyone [Eoorthis], Walcott [1908d, pp. 105-106] Eoorthis thyone. Thysanota Albers [1860, p. 63] A genus of the Gastropoda. (Thysanotos) [Obolus], Mickwitz [1896, pp. 194-195] Obolus (Mickwitzella). (Thysanotos) siluricus [Obolus], Mickwitz [1896, pp. 195-199] Obolus (Mickwitzella) siluricus. (Thysanotus) [Obolus], Walcott [1901, p. 683] Obolus (Mickwitzella). torrentis [Leptobolus], Matthew [1903, pp. 74-75] Lingulella torrentis. torrentis [Obolus], Matthew [1902c, p. 94] Obolus? torrentis. Matthew [1903, p. 76] Do. transversa [Linnarssonella], Walcott [1908d, p. 92] Linnarssonella transversa. transversa [Linnarssonia], Hall and Clarke [1892a, PL III, figs. 22 and 23] . Acrotreta sagittalis transversa. Hall and Clarke [1892c, p. 108] Do. Matthew [1886, p. 35] - Do. Matthew [1895a, p. 125] Do. Walcott [18S5a, p. 115] Do. transversa [Linnarssonia sagittalis], Freeh [1897, PL lA, fig. 3b] Do. Walcott [1891a, desc. of PL LXVIII, figs. 2a, 2c, and 2d] Do. transversa [Nisusla festinata], Walcott [1905a, p. 251] Nisusia festinata transversa. transversa [Obolella], Hartt [1868, p. 644] Acrotreta sagittalis transversa. Hartt [1878, p. 644] Do. Hartt [1891, p. 644] Do. Walcott [1884a, p. 16] Do. transversa [Orthisina?], Walcott [1886b, p. 121] Nisusia festinata transversa. Walcott [1891a, p. 613] Do. transversa [Ungula], Pander [1830, pp. 59 and 154, PL III, fig. 24] Obolus apoUinis quenstedti. Pander [1830, pp. 59 and 163, PL XXVIII, figs. 7a-b and 8a-b?] Obolus apoUinis. The text includes also Obolus apollinis quenstedti. Trematis pannulus AVhite [1874, p. 6] Micromitra (Iphidella) pannula. \\Tiite [1877, pp. 36-37] Do. Trematobolus Hall and Clarke [1892a, p. 252] Trematobolus. Hall and Clarke [1892b, p. 568] Do. Matthew [1893a, pp. 276-279] Do- Matthew [1894, pp. 88-90] Do. Matthew [189.5a, pp. 122-125] Do. Walcott [1908e, Pi: XI, and pp. 142 and 146] Do. Trematobolus excelsis Walcott [1908d, pp. 80-81] Trematobolus excelsis. Trematobolus insignis Hall and Clarke [1892a, p. 252] Trematobolus insignis. Hall and Clarke [1892b, p. 568] Do. Matthew [1893a, pp. 276-279] "■ - Do. Matthew [1894, pp. 88-90] Do. SYNONYIMIC REFERENCES. 95 Fresent reference. Trematobolus insignis Matthew [lS95a, pp. 122-125] Trematobolus insignis. Matthew [1895c, p. 95] Do. Matthew [1898, p. 35] Do. triangularis [Obelus], Mickwitz [1896, pp. 145-147] Obolus triangularis. Moberg and Segerberg [1906, p. 65] Do. Westerg&rd [1909, p. 56] Do. triangularis [Ungula], Pander [1830, pp. .59, 1.54, and 163] Obolus apoUinis. triangularis inornatus [Obolus], Mickwitz [1896, pp. 148-149] Obolus triangularis. triparilis [Obolus], Matthew [1902c, p. 94] Lingulella triparilis. triparilis [Obolus (Eoobolus)], Matthew [1903, pp. 136-137] Do. Triplecia? calcifera Hall and Clarke [1892c, p. 270] Syntrophia calcifera. Triplecia? primordialis Hall and Clarke [1892c, p. 270] Syntrophia primoi'dialis. Triplesia calcifera Walcott [1884b, pp. 7-5-76] Syntrophia nundina. Triplesia lateralis "UTiitfield [1886, p. 303] Syntrophia lateralis. Triplesia primordialis 'WTiitfield [1878, p. 51] Syntrophia primordialis. ■^Tiitfield [1882, p. 172] Do. tritavus [Leptobolus atavus], Matthew [1903, p. 109] Lingulella torrentis. tuUbergi [Orthis (Plectorthis)], Moberg and Segerberg [1906, p. 69] Eoorthis tuUbergi. Walcott [1905a, p. 271] Do. tumida [Lingulella], Matthew [1899b, p. 200] Lingulella tumida. Matthew [1903, p. 123] Do. tumeri [Acrothele], Walcott [1908d, pp. 87-88] Acrothele turneri. typicalis [Schizambon], Hall and Clarke [1892a, p. 253] Schizambon typicalia. Hall and Clarke [1892c, pp. 114, 116, and 117]. . Do. Walcott [1884b, pp. 70-71] Do. U. ulrichi [Acrotreta], Walcott [1908d, pp. 96-97] Acrotreta ubichi. undosa [Kutorgina], Moberg [1892b, p. 112] Micromitra (Paterina) undosa. unguiculata [Crania], Eichwald [1829, p. 274] Siphonotreta unguiculata. unguiculata [Siphonotreta], Davidson [1853, PI. IX, figs. 261-265, 269, and 270] Do. Davidson [1877, pp. 14 and 15] Do. Eichwald [1860, pp. 915-916] Do. Gagel [1890, p. 23] Do. Hall and Clarke [1892a, p. 253] Do. Hall and Clarke [1892c, p. Ill] Do. Kutorga [1848, pp. 264 and 284] Do. Quenstedt [1871, p. 674] Do. Quenstedt [1885, p. 755] Do. Schmidt [1861, p. 218] Do. de Verneuil [1845, pp. 286-287] Do. Walcott [1884b, p. 16] Do. Zittel [1880, p. 666] Do. unguiculata var. a [Siphonotreta], Kutorga [1848, p. 284] Do. unguiculata var. ^ [Siphonotreta], Kutorga [1848, pp. 264-265] Do. unguiculata var. y elongata [Siphonotreta], Kutorga [1848, p. 26-5] Do. unguiculata [Terebratula], Eichwald [1840, pp. 138-140 (24-26)] Do. Eichwald [1842, p. 145] Do. unguiculus [Lingulella], Salter [1866a, p. 285] Lingulella feiTuginea. Ungula Dall [1877, p. 75] Obolus. Pander [1830, pp. 57-58] Do. Ungula convexa Pander [1830, pp. 59 and 163] Obolus apollins quenstedti. Ungula ovata Pander [1830, p. 59, PI. XXVIII, figs. 6a-b] Obolus (Schmidtia) celatus. Pander [1830, pp. 59 and 154, PI. Ill, fig. 23] Obolus apollinis. Ungula plana Pander [1830, pp. 59 and 163] Do. Ungula plana or convexa Pander [1830, p. 163] Do. Ungula rotunda Pander [1830, pp. 59 and 163] Do. Ungula transversa Pander [1830, pp. 59 and 154, PL III, fig. 24] Obolus apollinis quenstedti. Pander [1830, pp. 59 and 163, PL XXVIII, figs. 7a-b and 8a-b?] Obolus apollinis. The text includes also Obolus apollinis quenstedti. Ungula triangularis Pander [1830, pp. 59, 154, and 163] Obolus apollinis. imgula [Orthis], von Buch [1841, pp. 7-8] Do. 96 CAMBRIAN BRACHIOPODA. Present reference. Unguliten von Buch [1841, p. 7] Obolus. Pander [1830, pp. 55-58] Do. Quenstedt [1837, pp. 143-145] Do. Ungulites Quenstedt [1885, p. 756] Do. Ungulites apoUinis Quenstedt [1885, pp. 755 and 756] Obolus apollinis. Ungulites sp. Quenstedt [1837, pp. 143-145] Obolus apollinis quenstedti. unxia [Syntrophia?], Walcott [1908d, pp. 108-109] Syntrophia? unxia. upis [Obolus (Lingulella)], Walcott [;905a, pp. 331-332] Lingulella upis. uplandensis [Acrotreta], Walcott [1905a, p. 302] Acrotreta uplandica. uplandica [Acrotreta], Wiman [1902, p. 54] Do. uplandica limonensis [Acrotreta], Walcott [1905a, p. 303] Acrotreta uplandica limoensis. urania [Linnarssonella], Walcott [1908d, pp. 92-93] Linnarssonella urania. utahensis [Iphidella labradorica], Walcott [1905a, p. 306] Micromitra (Paterina) labradorica utahen- sis. utahensis [Nisusia (Jamesella)], Walcott [1905a, pp. 255-256] Nisusia (Jamesella) utahensis. utahensis [Otusia], Walcott [new] Otusia utahensis. V. varians [Discina], Ban-ande [1868a, pp. 103-104] Orbiculoidea varians. Barrande [1868b, p. 692] Do. Pompeckj [1896a, p. 4] Do. vaticina [Orthisina], Mallada [1875, p . 32] Nisusia? vaticina. de Verneuil and Barrande [1860, pp. 533-535] Do. ventrosus [Obolus (Acritis) antiquissimus], Mickwitz [1896, pp. 213-214].. Obolus (Acritis) antiquissimiis. vermilionensis [Obolella], Walcott [new] Obolella vermilionensis. vermontana [Huenella], Walcott [new] Huenella vermontana. verrucosa [Siphonotreta], Davidson [1853, PI. IX, figs. 267 and 268] Siphonotreta verrucosa. Eichwald [1860, pp. 916-917] Do. Gagel [1890, p. 22] Do. ' Kutorga [1848, pp. 266-267] Do. Morris [1849, PL VII, figs. 2a-d] Do. Quenstedt [1871, p. 674] Do. Quenstedt [1885, p. 755] Do. Schmidt [1861, p. 218] Do. de Verneuil [1845, p. 287] Do. verrucosa [Terebratula], Eichwald [1840, pp. 140-141 (26-27)] Do. villaboimensis [Acrothele], Delgado [1904, p. 365] Acrothele villaboimensis. volborthi [Obolus], Mickwitz [1896, pp. 155-157] Obolus volborthi. Volborthia Hall and Clarke [1892a, p. 249] .' Volborthia. Hall and Clarke [1892b, p. 565] Do. Hall and Clarke [1892c, pp. 95-96] Do. von MoUer [1874, pp. 449-452] Do. Walcott [1908e, PI. XI, and pp. 142 and 143] Do. Volborthia recurva Hall and Clarke [1892a, figs. 261 and 262, p. 249] Volborthia recurva. Hall and Clarke [1892b, figs. 261 and 262, p. 565] Do. Hall and Clarke [1892c, pp. 95-96] Do. von Moller [1874, pp. 449-452] Do. W. walcotti [Strophomena (Eostrophomena)], Moberg and Segerberg [1906, p 71] Eostrophomena elegantula. wanneri [Yorkia], Walcott [1897b, p. 715] Yorkia wanneri. wanniecki [Lingulella], Redlich [1899, p. 7] Lingulella wanniecki. wanniecki [Obolus (Lingulella)], Walcott [1905a, p. 332] Do. wapta [Micromitra (Paterina)], Walcott [1908d, p. 59] Micromitra (Paterina) wapta. warthi [Lingula?], Waagen [1885a, pp. 769-770] Lingulella kiurensis. Waagen[1891, PL II, figs. 18a-b] Do. warthi [Neobo'us], Freeh [1897, PI. lA, figs. 5a-b] Neobolus warthi. Hall and Clarke [1892a, p. 245] Do. Hall and Clarke [1892b, p. 561] Do. Hall and Clarke [1892c, p. 84] Do. Oehlert [1887, p. 1263] Do Waagen [1885a, pp. 758-759] Do. Waagen [1891, PL II, figs. 5-9] Do. warthi [Orthis], Waagen [1891, pp. 102-104] Wynnia warthi, SYNONYMIC REFERENCES. 97 alandensis. aurora. balticus. blackwelderi. bottnicus. chuarensis. dartoni. ella. ella onaquiensis. elongatus. escasoni. Present reference. wasatchensis [Obolus (Westonia)], Walcott [1908d, pp. 69-70] Obolus (Westonia) wasatchensie. washingtonensis [Yorkia?], Walcott [1897b, pp. 715-716] Yorkia? washingtonensis. weeksi [Swantonia], Walcott [1905a, p. 297] Swantonia weekai. welleri [Obolus (Lingulella)], Walcott [1902, p. 608] Lingulella welleri. (Westonia) Matthew [1903, pp. 205-206] Obolua (Westonia). (Westonia) [Obolus], Walcott [1901, pp. 683 and 691] Do. Walcott [1908e, PI. XI, and pp. 142 and 144] Do. (Westonia) alandensis [Obolus], Walcott [1905a, p. 334] Obolus (Westonia (Westonia) aurora [Obolus], Walcott [1901, p. 691] Obolus (Westonia (Westonia) baltica [Obolus], Walcott [1905a, p. 334] Obolus (Westonia; (Westonia) blackwelderi [Obolus], Walcott [1905a, p . 335] Obolus (Westonia (Westonia) bottnica [Obolus], Walcott [1905a, pp. 335-336] Obolus (Westonia (Westonia) chuarensis [Obolus], Walcott [1901, p. 691] Obolus (Westonia (Westonia) dartoni [Obolus], Walcott [1908d, p. 67] Obolus (Westonia (Westonia) ella [Lingulella], Grabau and.Shimer [1907, p. 193] Obolus (Westonia (Westonia) ella [Obolus], Walcott [1901, p. 691] Do. (Westonia) ella onaquiensis [Obolus], Walcott [1908d, pp. 67-68] Obolus (Westonia' (Westonia) elongatus [Obolus], Walcott [1908d, p. 68] Obolus (Westonia; Westonia escasoni Matthew [1903, pp. 206-209] Obolus (Westonia; (Westonia) escasoni [Obolus], Walcott [1901, p. 691] Do. (Westonia) euglyphus [Obolus], Walcott [1901, p. 691] Obolus (Westonia) euglyphus. (Westonia) finlandensis [Obolus], Walcott [1902, pp. 611^12] Obolus (Westonia) finlandensis. (Westonia) iphis [Obolus], Walcott [1905a, p. 336] Obolus (Westonia) iphis. (Westonia?) lamellosus [Obolus], Walcott [1901, p. 691] Obolus (Westonia?) lamellosus. (Westonia) notchensis [Obolus], Walcott [1908d, p. 69] ..Obolus (Westonia) notchensis. (Westonia) rogersi [Obolus], Walcott [1901, p. 691] Obolus (Westonia) rogersi. (Westonia) stoneanus [Obolus], Walcott [1901, p. 691] Obolus (Westonia) stoneanus. (Westonia) themis [Obolus], Walcott [1905a, pp. 336-337] .Obolus (Westonia) themis. (Westonia) wasatchensis [Obolus], Walcott [1908d, pp. 69-70] Obolus (Westonia) wasatchensis. (Westonia) wimani [Obolus], Walcott [1905a, p. 337] Obolus (Westonia) wimani. whiteavesi [Bicia], Walcott [1901, p. 680] Bicia whiteavesi. whitfieldi [Billingsella], Schuchert [1897, p. 159] Billingsella whitfieldi. Walcott [1905a, p. 246] Do. whitfieldi [Kutorgina], Walcott [1884b, pp. 18-19] Do. wichitaensis [Orthis (Plectorthis)], Walcott [1905a, pp. 271-272] Eoorthis wichitaensis. wichitaensis laeviusculus [Orthis (Plectorthis)], Walcott [1905a, p. 272] Eoorthis wichitaensis leeviusculus. williardi [Micromitra (Paterina)], Walcott [1908d, p. 60] Micromitra (Paterina . williardi. willisi [Obolus (Lingulella)], Walcott [1898b, pp. 418-419] , Obolus willisi. Wimanella Walcott [1908d, pp. 98-99] 1 -..Wimanella. Walcott [1908e, PI. XI, and pp. 142 and 148] Do. Wimanella inyoensis Walcott [1908d, p. 99] Wimanella inyoensis. Wimanella shelbyensis Walcott [1908d, p. 100] Wimanella shelbyensis. Wimanella simplex Walcott [1908d, p. 101] Wimanella simplex. wimani [Obolus (Westonia)], Walcott [1905a, p. 337] Obolus (Westonia) wimani. wimani [Orthis (Plectorthis)], Moberg and Segerberg [1906, p. 70] Eoorthis wimani. Walcott [1905a, p. 272] Do. winfieldensis [Orthis (Plectorthis) remnicha], Walcott [1905a, p. 270] Eoorthis remnicha winfieldensis. wingi [Protorthis], Walcott [1905a, p. 286] Protorthis wingi. winona [Lingula], Hall [1863, p. 126] Lingulella winona . Hall [1867, p. 102] Do. Sardeson [1896, p. 96] Do. winona [Lingulella], Schuchert [1897, p. 258] Do. winona convexus [Obolus (Lingulella)], Walcott [1901, p. 691] Lingulella winona convexa. wirrialpensis [Obolella], Etheridge [1905, p. 248] Obolella wirrialpensis. wirrialpensis calceoloides [Obolella], Etheridge [1905, p. 249] Do. wirthi [Lingula], Barrande [1868a, p. 101] Lingulella wirthi. Barrande [1868b, p. 691] Do. woodworthi [Acrothele], Walcott [1908d, p. 88] Acrothele woodworthi. wortheni [Obolus], Walcott [1908d, pp. 63-64] Obolus wortheni. wynnei [Neobolus], Waagen [1885a, pp. 759-761] Neobolus warthi. Waagen [1891, PI. II, figs. 10 and 11] Do. Wynnia Walcott [190Se, PI. XI, and pp. 142 and 148] : Wynnia. 62667°— VOL 51, pt 1—12 7 98 CAMBRIAN BKACHIOPODA. Y. Present reference. yorkensis [Acrothele], Walcott [1908d, pp. 88-89] Acrothele yorkensis. Yorkia Walcott [lS97b, p. 714] Yorkia. Walcott [1908e, PL XI, and pp. 142 and 146] Do. Yorkia miqueli Walcott [new] Yorkia miqueli. Yorkia? orientalis Walcott [1906, pp. 569-570] Yorkia? orientalis. Yorkia wanneri Walcott [1897b, p. 715] Yorkia wanneri. Yorkia? washingtonensis Walcott [lS97b, pp. 715-716] Yorkia? washingtonenais. Z. zeno [Eoorthis], Walcott [1908d, p. 106] Eoorthis zeno. zenobia [Micromitra], Walcott [new] Micromitra zenobia. zetus [Obolus (Lingulella)], Walcott [lS98b, p. 419] Obolus zetus. zeus [Lingulella], Walcott [new] Lingulella zeus. zoppi [Obolua?], Walcott [1901, pp. 684-685] Obolus? zoppi. GEOLOGIC DATA. GENERAL GEOGRAPHIC AND STRATIGRAPHIC DISTRIBUTION. The distribution of the Bracliiopoda, both Cambrian and Ordovician, is set forth in the four tables following. The first (pp. 98-109) gives the general geographic and stratigraphic distri- bution of the various Cambrian and Ordovician species, arranged zoologically; the second (pp. 110-112) gives a summary of the Cambrian Brachiopoda by genera and by famihes; the tliird (p. 113) a summary of the Ordovician Bracliiopoda by genera and by families; and the fourth (p. 113) a general summary by families of all the Brachiopoda described in this paper, whether Cambrian or Ordovician. The question of the systemic reference of some of the formations (e. g., whether the Orlhoceras limestone and the Ceratopyge Umestone should be placed in the Ordovician or the passage beds between the Upper Cambrian and Ordovician, or whether the Ceratopyge slate, the Brijograptus slate, and the Dictyograptus slate should be referred to the Upper Cambrian or the Ordovician, etc.) does not appear to be a vital one in connection with this monograph. Whenever possible, however, the localities included in these pages contain the names of the formations represented, and these should enable the student to refer the species to the desired place in the geologic column. DISTRIBUTION BY SPECIES. The following table gives the general geographic and stratigraphic distribution of the Cambrian and Ordovician Brachiopoda taken up in this monograph: General geographic and stratigraphic distribution of the Cambrian and Ordovician Brachiopoda. No. Page. 1 Illustration. Stratigraphic position. Recur- rent species and varie- ties. Dis- tinct species and varie- ties. Name. Cambrian. Pas- sage beds. Or- dovi- cian. General geograpliic position. o Low- er. Mid- dle. Up- per. ATREMATA. 1 2 327 328 PI I . X X Fig. 19 2 2 1 2 3 4 5 329 330 331 332 332 PI VI X' X' Sweden and Finland. VI, LIX X X X VI California and Nevada . VI X' Rnrfiiriifi, 3 3 1 S a Type locality in italic. b The exact stratigraphic position of this species is not definitely known. GENEEAL GEOGRAPHIC AND STRATIGRAPHIC DISTRIBUTION. 99 General geographic and stratigraphic distribution of the Cambrian and Ordovidan Brachiopoda — Continued. No. Page. Illustration. Stratigraphic position. Recur- rent species and varie- ties. Dis- tinct species and varie- ties. Name. Camlirian. Pas- sage beds. Or- dort- cian. General geograpliic position. Low- er. Mill- die. Up- per. ATREMATA— Cont'd. 1 2 3 4 5 6 7 7a 8 9 337 337 338 339 339 340 341 342 342 343 PI. II X X x' Sis. Fie. 20 PI. II.... X in ' X X Montana, "Wyoming, and Ari- zona. Sweden, Bornholm and En''- in X Fig. 21 X land. PI. Ill X x V Montana, Wyoming, Utali, and Nevada. sculptilisendlielii.. Fig. 22 23 X X ■Rn'tisli Onlnmhia PI. Ill Wyoming. Total species 2 7 3 1 3 9 1 1 2 3 4 4a 4b 4d 5 6 7 S 9 9a 10 11 12 13 14 344 345 346 347 348 348 349 350 350 351 351 352 363 354 354 355 356 357 358 PI. II Micromitra (PaterinaJ: bell a X Quebec, Newfomidland Labra- Ill X X" X dor, Massachusetts, Vermont, and Pennsylvania. Ill Tennessee. II X II V V V Brunswick, Quebec. New York, Nevada, British Colum- bia, and England. Shantung, China. talis. II V } V toneusis. fPl. II . . \Fig. 24 logani PI. II X Quebec. Fig. 25 X X X phillipsi PI. III. . . X England. prospectensis II Ill X V X X Neil) York, Missouri (?). and British Columbia (?). stissingensis ora stuarti Fig. 26 Utah superba /PI. II } X X }x \Fig. 27.... Fig. 28 wapta 29.. williardi /PI. II Total species 8 2 7 4 2 3 1 14 5 Total varieties 1 2 3 4 4a 4b 359 3B0 360 361 304 365 Fig. 31... Micromitra (Iphidella): louise X Alberta PI. Ill X X X V V omatella III... . Sweden, Norway, Bornliolm,and Newfoundland. British Colimibia, Montana, fPl. IV . }x X panniila maladensis PI. IV York, and Cape Breton. pannulaophireusis. IV and Shantung, China ( ? ) . Total species 2 3 2 1 2 4 2 Total varieties 1 1 ' 1 1 2 3 4 6 5a 5b 5c 366 368 369 380 380 380 381 381 384 384 384 fPl.I } X Russia. Pl.LXIII Helmersenia ladogensis. X Do I Curticia elegantula X Minnesota. Obolus acadicus XI X Cape Breton. ? advenus XII X X X anceps X X ? ancillus XII apollinis fPl. VII, XIV } X X V V V (Russia, Finland, East and West \ Prussia, Sweden, and Poland. apollinisingricus..- apollinis maximus. . PI. VII, XIV Do. apollinis quenstedti Fig. 34 Do. ■ The exact stratigraphic position of tiiis species is not defin tely known. 100 CAMBEIAN BRACHIOPODA. General geographic and stratigraphic distribution of the Cambrian and Ordovician Brachiopoda — Continued. No. Page. Illustration. . Stratigrapliic posit'on. Recur- rent species and varie- ties. Dis- tinct species and varie- ties. Name. Cambrian. Pas- sage beds. Or- do\i- cian. General geographic position. Low- er. Mid- dle. Up- per. ATREMATA— Cont'd. Obolus— Continued. 6 7 8 9 10 U 12 13 14 16 16 17 18 19 19a 20 21 21a 21b 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 31 52 52a 52h S3 54 55 56 57 58 59 60 61 62 63 64 65 66 385 386 387 387 388 389 390 390 390 391 392 393 393 393 395 395 390 398 398 399 400 402 402 403 403 404 405 405 405 406 406 406 407 407 408 408 408 409 409 410 411 411 412 412 413 414 415 415 416 417 417 418 418 419 419 420 421 421 422 422 422 423 423 423 423 423 PI. XV X belli XXXVIII X Quebec. XXXIX X Shantung, China. Bohemia. coraplexus XII. X X X X XXVII discoideus XVIII X X Montana, Utah Idaho and dolatus Fig. 35. Nevada. Minnesota. X X elegans . PI. XV Do. XII X XXIII X ? inflatus X PI. XI X X lamhnmi XXII. X V Missouri, Tennessee, Virginia, and Georgia. Tennessee. lambomi minimus. XXV. IX X ■mnpnTinpni , , XXIII X V V X X British Columbia, Alberta, Mon- XXIII V V X X X tana, Utah, Nevada, and Cali- fornia. piens. XXIII, XXXIX . maera X X Nevada, Colorado, and Ver- matinalis VIII X mont (?). Montana, Wyoming, Idaho, VIII Utah, Colorado, Texas, Okla- homa, Minnesota-^ Wiscon- sin,(i Virginia, Missouri (?), and Vermont (?). membranaceus Fig. 36 X X British Columbia. meneghinii mickwitzi PI. XXX X X Wisconsin. XI X XV X ?rairandus . . XII X X Bohemia. XV namouna. VIII . . . X X X X X Wisconsin and Minnesota. nnndinft XI Nevada and Texas. obscurus . . XI Shantung and Shansi, Cliina. ? palliatus XV X Bavaria. pandemia IX. X Tennessee. panderi X Russia. Fig. 37 X pheres PI. XI X Wisconsin. XXVII X refulgens IX X X New Brunswick andCapeBreton. IX X ? rokitzanensis XII X X Bohemia. XX X X X Montana, Utah, Nevada, Wyo- XXX ming, and Georgia. Sweden and Demnark. schmidti XV X Russia. XXXVI, XXXVII XXIII, XXXIV X X X X Cape Breton. sbansiensis XI Shansi and Shensi, China. XXVI X smithi Fig. 38 X souri, Tennessee, Alabama, and Texas. PI. IX X X V V Montana, Wyoming, Arizona, tetonensis led a and Utah. Utah. PI. VIII, XI . . . Idaho, Oklahoma, and Texas. ? torrentis X Cape Breton. triangularis volbori;lii X X X X X Hussia and Sweden. Russia. PI. XXIII X X X X Alabama, Georgia, and Ten- rpi. IX }..... nessee. Idaho. \Fig. 39 PI. XXV XXX Sardinia. X X New York. X" Nevada. X Do. X X X Vermont. PI. XV Argentuia. China. ?sp. undt. f XV X Sweden. Total species 3 29 3 31 7 6 16 19 2 66 8 a The exact stratigraphic position of this species is not definitely known. b See footnote on p. 401. GENERAL GEOGRAPHIC AND STRATIGRAPHIC DISTRIBUTION. 101 General geographic and stratigrapMc distribution of the Cambrian and Ordovidan Brachiopoda — Continued. No. Page. Illustration. Stratigraphie position. Recur- rent species and varie- ties. Dis- tinct species and varie- ties. Name. Cambrian. Pas- sage beds. Or- dort- cian. General geograpliic position. Low- er. Mid- dle. Up- per. ATREMAT.\— Cont'd. Obolus (Broggeria): salteri 1 1 la 424 426 427 PI. XIII, XV... X X Norway, Sweden, ^Tijiired, and Cape Breton. Cape Breton. Do XXXII Obolus (Palaeobolus): X V bretonensis lens Total species 1 1 1 1 Total varieties 1 2 3 428 429 429 PI. LI Obolus (Pordinia): bellulus X • JVCTSiia and Utah (?). LI X X LXIII Do 2 1 3 1 2 431 432 PI. XVI ;.. Obolus (Lingulobolus): affinis X X Newfoundland and Massachu- setts. Do. XVI.XLII Total species 2 2 1 1 2 434 437 441 PI. XV Obolus (Miclavitzella): siluricus X xni.xv Obolus (Acritis): X Russia and Germany. XIII X Total species 1 1 2 1 2 3 4 442 444 440 448 PI. XIV Obolus (Srtimidtia): X X X X celatus XIV xrv obtusus xrv Total species 4 « 4 1 2 3 4 5 G 7 8 8a 9 10 11 12 13 14 15 16 17 18 19 20 21 22 451 451 453 453 454 454 455 455 459 459 459 461 462 462 463 463 463 465 466 466 467 468 468 PI. XLVIII Obolus (Westonia): Xa Sweden and FinlaJid (North Baltic region). XLVI X balticus XLVIII X" X X" X X X V Sweden and Finland (North Baltic region). Shantung, China. Sweden and Finland (?) (North Baltic region). blac'lrwelderi XXXIX bottnicus XLVIII XXV dartoni Fig. 40 Wyoming. ella PI. XXXIII, XLVIL. XLIX X X Idaho, Wyoming, Utah, Colo- rado, Nevada, Tennessee, and Alabama. elongatus LXIII X Do XLIX X" X X X Cape Breton. eugl\'plius XLVIII finia'ndensis XLVIII Finland Iptiis XLIX X X X X X XII notebensis LXIII Utah XLU XXVIII, XLIX .. X and Newfoundland. Wisconsin, New Jersey, and New Mexico. themis XI X X X" /PI. XLIX } Utah and Idaho. PI. XLVIII sp. undt. a X Shantung, China. sp. undt. b X Total species 1 13 1 ■ 6 1 5 4 22 1 1 2 3 4 5 5a 6 474 476 477 478 479 480 480 PI. XVII Lingulella acutangula. . X X6 X X X V X X agnostorum XXX Mexico (?), and Nevada (?). ampla XXVIII X X arguta XXIV South Dakota (?). atava XXXV Cape Breton. Do. atavainsul£e XXXV auga xxrv Tennessee. o The exact stratigraphie position of this species is not definitely known. i> This species occurs in passage beds between the Middle and Upper Cambrian, but is entered as Middle Cambrian in the tables. 102 CAMBRIAN BRACHIOPODA. General geogra-phic and stratigrapMc distribution of the Cambrian and Qrdovician Brackiopoda — Continued. No. Page. Illustration. Stratigraphic position. Recur- rent species and varie- ties. Dis- tinct species and varie- ties. Name. Cambrian. Pas- sags beds. Qr- dovi- cian. General geographic position. Low- er. Mid- dle. Up- per. ATREMATA— Cont'd. Lingulella— Continued. 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 ■ 37 38 39 40 41 42 43 43a 44 45 46 47 48 49 50 61 52 52a 63 64 55 56 57 68 59 60 61 62 63 64 65 66 67 68 69 70 481 482 4S3 483 484 484 485 486 486 486 488 489 489 489 491 492 494 495 496 500 500 501 502 502 504 505 505 506 607 607 50S 508 508 509 509 511 512 612 612 513 514 515 516 617 618 519 620 521 621 521 522 622 .523 623 525 525 526 527 528 528 629 530 630 630 531 632 PI XIX, XXXVI . . X X X X ^Newfoundland and Rhode Island. XIX Newfoundland. billingsiana bornemanni XXIX Do. Xo X X Sardinia. XXIX Alabama. XXXV Cape Breton. XXX X Bavaria. Fig 42 X X X X X Nevada. PI XXXV Cape Breton. XXXIII, XXXIV XXVII X Cape Breton and Sweden (7). South Dakota. XXXIX X? Shantung, China. XXXII X X Bohemia. XXX XXXI X North Wales, South Wales, XXIX X England, Cape Breton, Ar- gentina, and China. Portugal. XX X X X X Colorado, Wyoming^ Montana, XXIV Idaho, Utah, Nevada, Ala- bama, Georgia, Tennessee, Missouri, South Dakota, and British Columbia. Nevada. XIX X Quebec. ferruginea. _ cf. ferruginea XXIX, XXX, XXXI, XXXV. XXX X X X X X WaleSf Sweden, Denmark, Nor- way, Newfoundland, Nova Scotia, New Brunswick, and Argentina. Bohemia. XXXV Cape Breton. , franklinensis XXVI Vermont. XXXIX India. XXXVIII X New Brunswick. grauTjllensis XXII X Xew York and Vermont. XXV X Alabama. XXXIX X Spain. XXIV X Montana, Wyoming, Idaho, and ?liuiniUima .'... XXX X Utah. Bavaria. XXVI X Tennessee and Georgia. xxxii' X X X Bohemia. XXVII Newfoundland. : I'' XXVII Quebec. iris XXVII X X Do. JPl. XXXIX I X X / I7(a/i, Nevada, Idaho, and Brit- \ ish Columbia. India. lFig-43 PI XXX XIX X V X X X New Brunswick. laevis grandis New Brunswick and Cape Bre- XXXIII ton. Cape Breton. 1^ XXIV Georgia. , .' XXXI X Norway, Sweden, Wales, Nova XLVIII X X X X Scotia, and New Brunswick. Arizona. XXX Sweden. XX X X Nevada, Utah, and Idaho (?). martinensis XXXVIII New Brunswick. XXXVII X X V New Brunswick and Cape Bre- XVIII X ton. Minnesota, Wisctmsm, and Iowa. mosia osceola XVIII Wisconsin. XXIV X Alabama. XXXI X Sweden. XXX X X X X X X? X England. XXXV X? Oklahoma and Missouri (?). "" j XVIII Wisconsin and Minnesota. perattenuata XXI X South Dakota. Texas, and Ari- XXVI zona. Minnesota and Wisconsin. pogonipensis XX X ifcuada,Utah(?), and ArizonaC?). XXVII New York. XXXI X" X X X South W ales. XX X Nevada. quadri lateralis XXXIX Alabama and Georgia. XLV New Brunswick and Cape Bre- randomensis XXI X ton. Newfoundland. XXXVII X Cape Breton. XXI X New York. siemiradzkii signata XXXI X Poland. XXX X Bavaria. a The exact stratigraphic position of this species is not definitely known. GENEKAL GEOGEAPHIC AND STEATIGRAPHIC DISTRIBUTION. 103 General geographic and stratigraphic distribution of the Cambrian and Ordovidan Brachiopoda — Continued. No. Page. Illustration. Stratigraphic position. Hecur- rent species and varie- ties. Dis- tinct species and varie- ties. Name. Cambrian. Pas- sage beds. Or- dovi- cian. General geographic position. Low- er. Mid- dle. Up- per. ATREMATA— Cont'd. Lingulella— Continued. 71 72 73 74 75 76 77 78 79 80 81 81a 82 S3 84 85 632 534 534 535 535 536 537 538 638 539 639 540 541 541 541 541 PI. XXI X X Minnesota, Wisconsin, Tennes- XXXU X see, Alabama, Missouri, Okla- homa, South Dakota, Colo- rado, Utah (?), Georgia, and Nevada. XXIII X Tennessee. XLIX X XXXV X X X Cape Breton. (Pl.XLV } Do. PI. XXIV Do. XXXVI X Texas. XXXIX X India. XXXVIII X X V New Jersey. XVIU xvin XXX X Fig. 45 X Scotland. PI. XXX X X Pennsylvania. 5 46 1 35 3 6 13 20 85 4 1 1 la lb 2 3 4 4a 5 6 7 8 9 10 11 12 13 542 545 550 551 551 551 554 555 555 556 556 557 558 558 559 559 660 PI. xrv Lingulella (Leptembo- lon): lingulseformis .X X xxxrv, XL, XLI, XLII. XLI Lingulella (Lingulepis): X V X X ginia. Alabama, Tennessee, Oklahoma, Texas, Nevada, Utah, Colorado, Wvoming, South Dakota, Minnesota, Ver- mont, Wisconsin, and Michi- gan. acuminata sequens. Fig 46 V New York. PI. XXXIX X X X V X X Shantung, China. xxxm, XLui.. X Cape Breton. XLIV Do. greg^va r.obusta Do. PI.XLIV . Do. XLV. . . Do. XXX X XXXVII. X Cape Breton. XXI X XIX... X Arizona. ? squamosa XXX X X England. XXXVII X 1 9 2 5 1 1 3 13 3 1 1 3 560 562 562 563 PI. XXIX DelgadeUa lusitanica. . . X Portugal. LI Elkania ambigua X X X LI Quebec. XXX, LI . Do. Total species 3 3 1 1 2 666 569 670 (PL I, LXXXI \Fig. 47 } X India. PL L ■Ripifl gpmmfi X X Quebec, Labrador, and New whiteavesi L York. New York. 2 2 1 2 3 4 5 6 7 672 573 574 575 575 578 578 PI. Lni... . Dicellomusappalacbia . X X X X X X X Tennessee, Alabama, and Vir- LIII X X gmia. Montana, Wvoming, South Da- parvus LXXXIX kota, and Missouri. ShantUTig and Shensi, China. /PI. LIL. I } X X /Montana, South Dakota, and \Fig. 48 \ Wisconsin. /PI. LII [Montana, Utah, Arizona, South 1 Dakota, Oklahoma, Tennes- \rigs. 16 and 49 PI. LXXXIX 1 see, Wiseonsin, Missouri, and [ Minnesota. Utah. pp. nriflt LII Sweden. Total species 7 3 1 4 7 104 CAMBRIAN BRACmOPODA. General geographic and stratigraphic distribution of the Cambrian and Ordovidan Brachiopoda — Continued. No. Page. Illustration. Stratigrapliic position. Recur- rent species and varie- ties. Dis- tinct species and varie- ties. Name. Cambrian. Pas- beds. Or- dovi- cian. General geographic position. Low- er. Mid- dle. Up- per. ATREMAT A— Cont'd. 1 2 3 4 5 6 580 582 683 583 684 684 fPl. V }x X Labrador, Quebec, Vermont, Kutorgina cingulata \Figs. 3, 8, and .60 Pi. V and Siberia. Newfoundland. V X° South. Australia. V X V X" Sardinia. X Virginia. 4 2 6 1 1 2 3 4 4a 6 6 7 8 9 10 11 685 688 589 691 692 595 695 696 696 597 698 699 699 Pi. LI X LV NEOTREMATA. X }x X }x V X X X X X X" X (Pl.LV (Newfoundland, Massachusetts, \ and Georgia. Labrador, Newfoundland, and IFig. 61 PI. LIV fPl. LIV New York. [Labrador, Quebec, Vermont, 1 New York, Pennsylvania (?), 1 Georgia (?), and Massachu- [ setts. crassa crassa elongata \Fig. 14 PI. LV Fig. 62 PI LV LIV Maryland, New York, Pennsyl- LV vania, Virginia, and West Vir- ginia. Sweden and Norway. Fig 53 wirrialpensis Pi LV South Australia. 11 1 11 1 1 1 2 3 4 600 602 603 606 607 Pi.LV Obolella (Glyptias) : favosa X Sweden and Norway. Bctsfordia? barrandei.. LVII X X X X Spain. LIX X New Brunswick, Quebec, Ver- LVII mont,Labrador,andiVew; Ybrfc. India. LXII Total species 1 4 1 4 Schizopholis rugosa 1 1 1 2 3 4 609 610 611 612 612 613 PI I LXXXI X India. CIV X Quebec and Labrador. LXXXII Yorkia? miqueli X France. LXXXII X Shansi, China. LXXXII X X Quebec (?), Pennsylvania, and ? wasbingtonensis. . LXXXII California (?). New York. 2 1 1 4 1 1 2 3 4 614 617 617 619 621 Pi LXXXII X LXXXII X LXXXIV . X X X New Brunswick. kempanum LXXXIII Do. f LXXXIII } Do. \ LXXXIV 1 3 4 1 2 3 4 622 623 623 624 Pi LXXXIV X Russia. LXXXIV X LXXXIV X X Cape Breton and New Bruns- LXXXIV X wick, Nevada and Utah. 3 2 1 4 1 2 3 625 626 027 Pi. LXXXI Siphonotreta? dubia.,- unguiculata X LXXXI X X X X Russia and East and West LXXXI ' Prussia. Do. 1 2 2 2 3 a The exact stratigraphic position of this species is not definitely known. GENERAL GEOGRAPHIC AND STRATIGRAPHIC DISTRIBUTION. 105 General geographic and stratigraphic distribution of the Cambrian and Ordovician Brachiopoda — Continued. No. Page. Illustration. Stratigraphic position. Recur- rent species and varie- ties. Dis- tinct species and varie- ties. Name. Cambrian. Pas- sage beds. Or- dovi- cian. General geographic position. Low- er. Mid- dle. Up- per. NEOTBEMATA— Continued. Keyserlingia buchi 1 1 2 2a 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 17a 17b 17c 18 19 20 21 22 22a 23 24 25 26 27 28 28a 28b 29 30 31 32 33 34 628 634 634 636 636 637 638 639 639 640 640 642 644 644 645 646 646 647 647 649 649 660 650 650 651 652 653 653 654 654 655 655 656 656 659 659 660 660 661 661 662 662 PI. LXXXI. X Fig. 54 Acrothele artemis X X V avia Pl.LXI, LXII Cape Breton. Do bellapunctata PI. LVII X Norway. LVIII X X X bergeroni LVIII LVII LXIII X ceratopygarum LXIII X : Norway and Sweden. /British Columbia, Alberta, and \ Montana. Norway, Sweden, and Den- mark. Pennsylvania. fPl. LXIII }x X x» coUeni coriacea PI. LVI X decipiens LVIII X LX X X X gamagei LX... intermedia LVI X? Sweden, Denmark, and Eng- land (?). Quebec. levisensis LXXXI X LVII, LVIII X X V V ■ V X matthewi LXI X matthewi eryx LXI wick. Shantung, Ctiina. mattbewi lata LXI LXI Do tata. LXIII Shantung, China. nitida LVIII X X LIX pretiosa LVIII X Quebec and New York. New Brunswick and Cape Bre- ton. LXI, LXII X V X X X X LXI LVII land. Spain. Cape Breton. proles LXII quadrilineata LVII rata LXIII.. Shantung, China. spuni LX X LX X subsiduahera LX V lumbia. subsidua Isevis V X Utah Pl.LX villaboimensis X X Portugal. woodworthi Pl.LX yorkensis LIX... . X Pennsylvania. Quebec. sp. undt. a LXIII X X sp. undt. Moberg. . . Total species 10 1 21 6 3 2 2 4 34 7 Total varieties. .. 1 1 1 2 3 4 5 6 7 663 664 6C6 667 668 669 669 670 670 Pl.LVI Acrothele(Redlichella) : granulata X LXXXI Diseinolepis granulata. . X X India f LXXVIII X X X X X X Linnarssonella girtyi. . . } iVtah, South Dakota, O^ahoma, \ Texas, Nevada, and Missouri. \ LXXIX LXXIX minuta X modesta LXXVIII nitens LXXVIII Do tennesseensis LXXIX X transversa LXXVIII Utah vurania LXXVIII X Total species 3 6 1 3 7 1 2 2a 3 4 5 6 7 8 9 10 11 12 674 675 676 676 676 677 678 678 679 679 680 680 681 PI. LXVII Acrotreta argenta X X attenuata LXIV, LXXIX... LXV X V Nevada, Utah, Wyoming, and Montana. attenuata var babel LXXVIL X baileyi ; LXXVII X X bellatula LXXVIII Utah belti LXXVII X X North Wales and England. Cape Breton and New Bruns- wick. bisecta LXVI 7?caneellata LXXIX X X X carinata Fig. 56 circularis Fig. 67 Do claytoni PI. LXXIV X concentrica LXXVII X :::::::l Georgia. 'This species also occurs in passage beds between the Middle and Upper Cambrian. 106 CAJMBRIAN BRACHIOPODA. General geographic and stratigraphic distribution of the Oambrian and Ordovician Brachiopoda — Continued. No. Page. Illustration. Stratigraphic position. Recur- rent species and varie- ties. Dis- tinct species and varie- ties. Name. Cambrian. Pas- sage beds. Or- dovi- cian. General geographic position. Low- r. Mid- dle. Up- per. NEOTREMATA— Continued. Acrotreta — Continued. 13 14 IS 16 17 18 19 20 21 23 23 23a 23b 24 25 26 27 28 29 30 30a 30b 31 32 33 34 35 30 37 37a 37b 38 39 40 41 42 43 44 45 4B 46a 46b 46c 47 48 49 50 51 52 53 54 65 56 S6a 57 58 681 682 682 683 083 684 684 685 6S6 687 687 689 690 688 690 690 692 692 693 693 694 694 695 695 695 696 696 697 697 698 699 698 699 699 699 700 701 702 702 704 706 707 708 706 709 710 710 711 711 713 713 714 714 714 715 716 PI. LXXV X X X LXVI Cape Breton. LXVIII X LXIV X X Nevada, Idaho, and Wyoming, British Columbia. LXVI eggegrandensis LXX Sweden and Finland LXV X New York. LXVI X Newfoundland. LXVI, LXXVII.. X X X V V X New Brunswick and Cape Bre- ton. LXVI LXV, LXVIII... - X V V V X V Nevada, Utah, Idaho, Wyoming, Montana, and South Dakota. LXV LXV Utah and Idaho PL XV X Bavaria. LXXVI X X X X X V V fPl. LXV } X Alabama and Tennessee IFig. 58 lisani PI. LXVIII Shantung, China. marjiunensis. ...... microscopica microscopica mis- souriensis. microscopica teton- ensis. LXXVIII X X Utah. LXVII LXVII Missouri. LXVII Wyoming. LXXVII X Bohemia. LXXII X X Newfoundland and New Bruns- LXXVII wick. Utah. nicholsoni LXXIII X X X X Scotland, Ireland, and England. Wisconsin. LXXVII Sweden. PI. LXXIV X V V X Utah. ophirensis descen- dens. ophirensis rugosa. . . ct. ophirensis LXXVIII Do. LXXIV Do. Do. PI. LXVI X Quebec. LXIX ; X X X Shantung, China. LXXVII Sweden. LXIX X Nevada. LXIX X Nevada, Utah, Idaho, and Mon- LXV, LXXV tana. Tennessee. LXXIII X X England. LXXI X V X Sweden, Norway, Denmark, sagittalis magna sagittalis taconica.. sagittalis transversa cf. sagittalis LXVI Scotland, Ireland (?), Wales, Newfoundland. New Bruns- wick, and Quebec. New Brunswick. LXXI T LXXII V X X V bia. wick. Utah. PI. LXX LXXVII X X Norway and Sweden. shantungensis LXIX X X X Shansi, Shensi(?), and Shan- LXIX tung, China. LXXIII Sweden and Denmark. LXXIX X Nevada. LXXIII X Russia. LXXVIII X Oklahoma. LXX. X" X Sweden. uplandicahmoensis LXX Do. Cape Breton. sp. undt. Wester- X Total species 3 1 33 10 21 3 7 1 7 1 13 5 58 11 1 2 3 4 4a 4b 717 717 718 719 719 720 1 /PI. LXXVI } X X X X V V Idaho. Acrothyra -minor \Fig .59 PI. LXXV, LXXVI.. Cape Breton. "> LXXX Do. LXXX Do. signata orta signata prima LXXX Do. LXXX Do. Total suecies 4 2 4 2 1 The exact stratigraphic position of this species is not definitely known. I> This species also occurs in the passage beds between the Middle and Upper Cambrian. GENERAL GEOGRAPHIC AND STRATIGRAPHIC DISTRIBUTION. 107 General geographic and stratigraphic distribution of the Cambrian and Ordovieian Brachiopoda — Continued. No. Page. Illustration. Stratigraphic position. Recur- rent species and varie- ties. Dis- tinct species and varie- .ties. Name. Cambrian. Pas- sage beds. Or- dovi- eian. General geographic position. » Low- er. Mid- dle. Up- per. NEOTREMATA— Continued. Discinopsis gulielmi 1 " 2 720 721 PI. LXXXII X New Brunswick LXXXII X Shantung, China. Total species . . 1 1 2 1 2 3 722 722 723 PI. LXXXI Orbiculoidea contraria. . X Bavaria. LXXXI. . X North and South Wales. LXXXI X Bavaria. Total species 1 2 3 1 1 2 3 3a 4 5 724 726 727 727 729 729 730 PI. LXXXI X British Colum.bia c PROTREMATA. X X X" Brilish Columbia and Utah (?). South Australia. compta XCVII /PLC }x Labrador, Quebec, Vermont, ■ New York, Pennsylvania, and British Columbia. Vprmnnt \Fig. 6 festinata transversa. PI. C. Fig. 60 X X 1 ? vaticina PI. XCVII... 1 Spain. Total species . 2 1 4 1 5 1 1 2 3 4 5 6 7 8 9 ga 9b 10 11 12 731 731 732 732 732 733 734 735 735 730 730 737 737 738 PI. CI Nisusia (Jamesella): X X Quebec. CI CI X Do. X PI. CI X X lowi Fig. 61 British Columbia. Pl.XCIII X X Idahn, Utah (?), and British Columbia (1). XCVII perpasta CI. X V T } Bohemia. perpasta macra perpasta subquad- rata. CI Do. CI. . Do. (Pl.XCIII X X Idaho and Utah. utahensis PI. CI. Utah. X 6 2 5 1 12. 2 1 2 3 4 6 6 7 8 739 740 740 741 741 742 743 743 PI. xcix.; X X helena XCIX.. Do. xcv X laevis xcix. .. X Wisconsin. XCIX X X quacoensis XCIX Do. XCIII X X sp. undt Arizona. Total species 4 3 1 8 1 1 2 3 4 5 6 744 745 746 746 747 747 748 PI. XCIX Protorthis (Loperia): X LXXXVII wick. WiTTiaTipIla ? annrnflJa X X Alabam^a. LXXXVII Fig. 63 X saffordi PI. LXXXVII X Tennessee. II X }x simples /PI. LXXXIX \Fig.64 3 3 6 1 2 3 4 5 5a 6 750 760 751 754 754 765 756 PI. LXXXVII Billingsella? appalachia. X Fig. 65 X } coloradoensis fPl. LXXXV X X X X« ("Montana, Wyoming, Idaho, \Figs. 6 and 66.. . 1 consin, Minnesota. British Co- dice PI. CI [ lumbia, and New Brunswick. Vermont. expbrrecta LXXXVIII X V X X? ejcpoirecta rugosi- LXXXVII! Do. costata. hicksi XCVII South Wales . a The exact stratigraphic position of this species is not definitely known. 108 CAMBRIAN BRACHIOPODA. General geographic and stratigraphic distribution of the Cambrian and Ordovician Brachiopoda — Continued. No. Page. Illustration. stratigraphic position. Recur- rent .species and varie- ties. Dis- tinct species and varie- ties. Name. Cambrian. Pas- sage beds. Or- dovi- cian. General geographic position. Low- er. Mid- dle. Up- per. PEOTREMATA— Continued. BilUngsella— Cont'd, highlandensis 7 8 9 10 11 12 13 14 15 16 17 18 19 20 756 767 758 758 758 759 759 760 761 761 762 763 764 764 PI. LXXXVII LXXXVII X Nevada and California (?). X major LXXXVI. X Wisconsin and Missouri (?). Fig. 67 X X PI. LXXXVI. LXXXVI X } (PI. LXXXVI. X X X Montana and Wyoming. \Fig. 1 pilTnppIIyi PI. XCVII . Shantang, China. XC X richthofeni LXXXIX X Shantung, China. romingeri salemensis XC X LXXXVII LXXXVI... X Quebec and New York X X whitfleldi LXXXVI Nevada. Total species 5 12 1 5 2 4 20 1 1 2 2a 2b 765 765 769 769 PI. CI. Onisia eurekensis . X X Nevada. XCVIII X V V Norway, Sweden, Prussia, North Wales, Newfoundland, Cape Breton, New Brunswick, Ar- gentina, and Nevada. lenticularis atry- poides. lenticularis lynci- oides. xcvni XCVIII Do. Total species . 2 1 2 1 2 2 1 2 769 770 PI. XCIII Otusia sandbergl ntahensi^ X LXXXIX X Utah. 1 1 2 1 1 2 3 4 5 6 6a 7 8 9 10 11 13 13 14 15 16 17 18 19 20 21 21a 21b 21c 22 23 24 25 26 26a 27 28 29 771 773 774 775 775 776 777 778 778 779 779 780 780 781 782 782 782 783 784 784 785 785 786 787 787 788 788 789 789 790 790 791 791 792 792 fPl. LXXXIX |.Fig. 68 } X India. PI. LXXXIX X atava xcv. . X New Brunswick. XCVII X christianise xcv.. X Norway and Sweden. xcv X X East Prussia, Norway, and Sweden. XCVI X V X X X V desmopleura nym- pha. Tdiablo XCVI mine, New Mexico, British Co- lumbia (?), and Pennsylvania. Colorado and Wyoming. XCIII doris . XCVII. Shantung, China. hastingsensis iddingsi XCIV X XCI X X X X Wyoming and Texas XCIV XCVII kayseri XCVII Shantum and Shansi, China. kichouensis LXXXIX X Shansi, China. linnarssoni XCVII X X X X Shantung and Liaotv/iw, China. newberrvi Fig. 69 Utah. PI. XCVII pagoda. XCVII Shantujng, China. papias . . . XCI X X X Newfoundland. XCVII Spain. fWisconsin, Minnesota, Mon- \ tana, Utah (?), Oklahoma, and remnicha... fPl. XCI, XCII \Fig. 7 } X V V V X PI. XCII remnicha texana xcn. Oklahoma, Montana, Texas, and Missouri (?). AVisconsin. remnicha winfield- XCI ensis. saltensis XCVII Argentina. tatei XCVII . x« X South Australia. Fig. 70 Utah. tullbergi PI. xcv.. X Sweden. xcrv • X X V X X wlchitaensis laevi- xcrv Texas, Missouri, and Wyo- ming. Oklahoma and Texas. usculus. xcv X Sweden and Norway. ' Utah. zeno Fig. 71 X X sp. undt. a Bohemia. 1 The exact stratigraphic position of this species is not definitely known. GENERAL GEOGEAPHIC AND STEATIGEAPHIC DISTRIBUTION. 109 General geographic and stratigraphic distribution of , the Cambrian and Ordovician Brachiopoda — Continued. No. Page. Illustration. StratigrapMo position. Recur- rent species and varie- ties. Dis- tinct species and varie- ties. Name. Cambrian. Pas- sage beds. Or- dovi- cian. General geographic position. Low- er. Mid- dle. Up- per. PROTEEMATA— Continued. Eoorthis— Continued. 30 31 32 33 792 793 793 793 X X X Bobemia. PI. LXXXTX LXXXIX X Shantung. China. Total species . 14 18 5 5 2 1 6 1 J3 5 1 2 2a 794 795 795 PI. XCIII Knkelnbuigia flnkeln- burgi. X X V Wisconsin and Minnesota. XCIII WisconsiUf Minnesota, and Iowa. Osceola corrugata... 2 1 2 1 1 1 2 796 797 797 PI. xcv.. Eostrophomena ele- gantula. X Oeland Island, Sweden. CIV , Swantonia antiquata . . . X X CIV. Nevada. 3 2 1 2 3 4 5 6 7 8 9 9a 10 11 799 799 800 800 801 802 802 803 803 804 804 804 PI. cm SyntropMa alata X X Texas. CII CIV. X Quebec and Newfoundland. Cambria Fig. 72 X Utah. 73 X /PI. CII I X X nnndinn. \Fig. 11 PI. CII / X X X V X 2^evada, Utah, and Colorado. CIV primordialis primordlalisargia. . CII.. Minnesota, Wisconsin, Okla- CII homa, and Wyoming'. Minnesota. cm Wyoming. Utah. ? unxia Fig. 74 . X Total species 2 7 1 3 1 11 1 1 2 3 4 5 6 6a 7 805 806 807 807 808 808 80S 809 fpi.cm ipig. 13 TTnpnplla ahnnrmis \ X X" X" X / Montana and Wyoming, PI. CII etheridgei LXXXIX South Australia. Fig. 75 X X X V Utah. orientalis PI. CIV Shantung, China. cm Do. vermontana Fig. 76.. X Vermont. 4 4 1 1 7 1 Total varieties. 1 810 PI. CIV X o The exact stratigraphic position ot this species is not dellnitely known. no CMfflRIAN BEACHIOPODA. SUMMARY OF CAMBRIAN BRACHIOPODA. The distribution of the Cambrian Brachiopoda is summed up in three tables. The first (pp. 110-111) gives tlie general geographic and stratigraphic distribution of the genera; the second (p. 112) gives the same information for the families; and the third (p. 112) is a summary of the Cambrian Brachiopoda by genera and species. Summary of Cambrian Brachiopoda by genera. Cambrian. Passage teds. Recur- rent spe- cies and varieties. Distinct species. Distinct Lower. Middle. Upper, varieties. ATREMATA: RUSTELLID^ — Rustella, Species .. 2 2 PATERINIDiE— 3 2 3 7 1 3 5 9 3 1 2 1 (Paterina), Species 8 2 2 7 4 3 2 3 1 2 14 5 1 4 2 i : 1 15 2 20 6 7 1 a9 1 33 8 CtntTiciiD^— 1 1 OBOLID.iE— 3 29 3 31 7 1 6 615 62 1 54 8 1 1 1 1 1 2 1 1 3 1 2 4 18 1 1 1 4 6 (Westonia), species 1 13 1 46 1 1 c3 1 5 35 3 1 5 8 |J15 77 4 1 1 c2 1 13 1 9 2 2 1 1 1 2 7 1 2 7 3 /3 13 109 6 87 10 17 40 2 186 14 KUTORGINID^— 4 2 6 SCHUCHERTINIDiE — Schuchertina, species '. 1 1 NEOTREMATA: Obolellid.e— 11 11 1 4 1 1 14 5 1 18 1 a Two species pass up from the Lower to the Middle Cambrian, four from the Middle to the Upper Cambrian, and one from the Lower to the Upper Cambrian. One species is common to the Lower, Middle, and Upper Cambrian. One variety passes from the Lower to the Middle Cambrian. , , ^^ , ., . t> Fourteen species pass from the Middle to the Upper Cambrian and one continues mto the passage beds. Fom- of these species pass up from the Upper Cambrian to the Ordovician. , , ,, ^ tt ^ i. ■ r-. c One species is common to the Lower, Middle, and Upper Cambrian, and one species passes from the Middle to the Upper Cambrian. One species passes from the Upper Cambrian to the Ordovician. ,,..,, d Two species are common to the Middle and Upper Cambrian and pass up into the Ordovician; eleven species pass from the Middle to the Upper Cambrian; two species pass from the Upper Cambrian to the passage beds; and two species pass from the Upper Cambrian to the Ordovician. e Two species are common to the Middle and Upper Cambrian and pass up into the Ordovician. / One species is common to the Middle and Upper Cambrian; two species pass from the Middle to the Upper Cambrian; and one species passes from the Upper Cambrian to the Ordovician. GENERAL GEOGRAPHIC AND STRATIGRAPHIC DISTRIBUTION. Summary of Cambrian Brachiopoda hy genera — Continued. Ill Cambrian. Passage beds. Recur- rent spe- cies and varieties. Distinct species. Distinct Lower. Middle. Upper. varieties. NEOTREMATA— Continued. SlPHONOTEETrD.E— 2 1 1 3 1 4 1 4 3 3 1 Dearbornia. species . . ' . . 1 Schizambon, species 3 (") 1 2 Eeyserlingia, species 1 4 5 4 3 16 Total varieties. ACEOTEETID^— Acrothele, species 10 1 21 6 1 1 3 33 10 4 2 1 3 2 ci 32 7 (Redlicbella), species ... 1 1 7 53 Discinolepis, species 6 21 3 d2 /4 3 1 7 1 Varieties 11 4 Varieties . _ 2 Discinopsis, species 1 2 13 2 64 18 31 3 9 1 17 4 100 Total varieties - 20 DisciNn).B— 1 2 3 CKANTIDi:— 1 1 PROTREMATA: BtLLINGSELLID^— Nisusia, species 2 1 6 2 4 1 5 1 (Jamesella), species 5 1 12 2 4 1 3 12 1 2 3 1 8 1 6 19 Wimanella, species 3 5 5 S3 Varieties . . 1 Orusia, species 1 9 1 1 2 Varieties . - 2 1 1 14 2 1 33 Eoortbis species 18 5 2 1 5 hi 6 2 Varieties .... 1 16 3 47 1 31 8 6 8 91 12 SlEOPHOMENIDyE— Eostrophomena, species 1 1 2 2 9 Syntrophia, species 2 (0 1 4 1 7 1 2 6 11 2 1 18 2 a One species passes from the Upper Cambrian to the Ordovician. i> Two species pass from the passage beds to the Ordovician. c One species passes up from the Lower to the Middle Cambrian; two from the Middle to the Upper Cambrian; and one from the Middle Cam- brian to the passage beds. d Two species pass from the Middle to the Upper Cambrian and one species passes from the Upper Cambrian to the Ordovician. e Sis species pass from the Middle to the Upper Cambrian, of which one continues on into the passage beds; one species passes from the Lower to the Middle Cambrian, and one from the Upper Cambrian to the passage beds. One species is common to the Middle and Upper Cambrian and to the Ordovician; one species is common to the Upper Cambrian and the passage beds; and one species passes from the Upper Cambrian to the Ordovician. / Two varieties pass from the Middle to the Upper Cambrian and one variety is common to the Middle Cambrian, Upper Cambrian, and passage beds. (7 Two species pass from the Middle to the Upper Cambrian of which one continues into the Ordovician. One species passes from the Lower to the Middle Cambrian. ^ One species passes from the Middle to the LTpper Cambrian; one species is common to the Upper Cambrian, passage beds, and Ordovician; one species IS common to the Middle Cambrian, Upper Cambrian, and Ordovician; one species passes from the Upper Cambrian to the passage beds; one variety is common to the Upper Cambrian and the Ordovician. i One species is comm.on to the Upper Cambrian and the Ordovician. 112 CAMBRIAN BRACHIOPODA. Summary of Cambrian Brachiopoda by families. Cambrian. Passage beds. Genera, subgenera, species, and varie- ties. Lower. Middle. Upper. Recur- rent. Distinct. ATREMATA: RUSTELLID^— Genera . 1 2 2 2 1.5 2 1 2 • Paterinid^— Genera ... . . 2 2 20 6 2 2 7 1 1 1 3 5 87 10 3 4 9 1 3 2 Species 33 8 CURTICnD.E— 1 Species . . . , 1 Oboud.e— Genera . . . . , 4 2 13 4 5 109 8 1 2 1 1 2 3 5 17 1 40 2 1 6 9 Species . . 186 Varieties 16 Ktjtorginid^ — Genera 1 4 1 6 SCHUCHEETINID^— 1 Species . . 1 NEOTREMATA: Obolellid^— 3 1 14 1 3 4 2 1 4 Subgenera 1 5 1 18 1 Genera . 3 5 6 64 18 8 2 47 1 2 4 4 2 3 2 4 6 16 ACROTRETID^— 8 6 1 13 2 31 3 9 1 1 2 17 4 1 100 Varieties 20 BlSCINID^— 1 3 Cranhd.e — 1 1 PROTREMATA: BlLLINGSELLID^— Genera - . . . . 3 1 16 3 6 1 31 8 2 10 2 8 9 2 Species 6 91 12 STEOPHOMENID^— } 1 1 Syntrophiid^— 1 2 2 6 2 11 2 2 1 3 18 2 General summary of Cambrian Brachiopoda. Genera. Sub- genera. Species. Varieties. Species and va- rieties that pass on into the Ordo- vician. Atremata: 1 3 1 6 1 1 4 6 6 1 1 9 1 3 2 33 1 186 6 1 18 16 100 3 1 91 1 18 2 8 9 16 12 Neotremata: ObolellidEe ' 1 1 3 1 20 4 Frotremata: 2 12 4 2 1 Total 44 15 477 59 24 GENERAL GEOGRAPHIC AND STRATIGRAPHIC DISTRIBUTION. 113 SUMMARY OF ORDOVICIAN BRACHIOPODA. The Ordovician Brachiopoda are summarized in two tables, one by genera and the other by families: Summary of Ordovician Brachiopoda by genera. Species. Varieties. Species and varieties that pass up from Cambrian. ATREMATA: PATERINIDiE— Volborthiaa . . . 1 16 2 5 13 1 3 1 2 2 2 1 7 2 2 3 1 Obolidje— Obolus.. 4 (Lingulobolus) a (Westonia) 1 Lingulella 5 1 Elkania o . . . NEOTREMATA: SlPHONOTKETID^— Schizambon . J Siphonotreta 2 ACEOTEEXro^— Acrothele Acrotreta *. 1 3 PEOTREMATA: BlLLraGSELLID^— BUlingsella 1 3 Stntrofhtidj:— Clarkella a Total 64 3 a Found only in the Ordovician. Summary of Ordovician Brachiopoda by families.'' Genera. Sub- genera. Species. Varieties. Species and va- rieties that pass up from Cam- brian. Atremata: 1 4 2 3 2 2 1 41 4 10 4 4 OboUdae 3 1 Neotremata: Siphonotretidee Acrotretidae 1 1 4 Brotremata: BillingsellidEe Total 14 3 64 3 24 n This table includes all Ordovician species taken up in the monograph. With the exception of three genera, one subgenus, forty-two species, and one variety all ot these pa^s up from the Cambrian. (See pp. 122-123 for a list of the Ordovician forms taken up in this monograph.) GENERAL SUMMARY OF CAMBRIAN ANB ORDOVICIAN BRACHIOPODA. The following table gives a general summary of the genera, subgenera, species, and varieties, both Cambrian and Ordovician, in each of the families taken up in this monograph: General summary of Cambrian and Ordovician Brachiopoda. Genera. Subgenera. Species. Varieties. Atremata: Rustellida; 1 4 1 7 1 1 4 6 6 1 1 9 1 4 2 34 1 215 6 1 18 17 107 3 1 92 1 21 2 8 Curticiidae Obolidaj 10 17 KutorginidEe Neotremata: Schuchertinidae Obolellidas 1 1 Siphonotretidae Acrotretidae 1 20 Discinidae Craniidae Protremata: 2 Strophomenidae Syntrophiidae 2 Total 47 16 519 60 62667°— VOL 51, pt 1— 12 8 lU CAl'IBRIAN BEACHIOPODA. DETAILED GEOGRAPHIC DISTRIBUTION. In the following lists the various species of Cambrian Brachiopoda are listed by continents, as they occur in the various faunal provinces of Cambrian time in North America and in other countries. The record of the local distribution of each species will be found at the end of the description of the species. The tables are arranged under the following heads, the species being zoologically arranged under each head : 1. North American species of Cambrian Brachiopoda (p. 114). 2. European species of Cambrian Bracliiopoda (p. 120). 3. Asiatic species of Cambrian Brachiopoda (p. 121). 4. South American species of Cambrian Brachiopoda (p. 122). 5. Australian species of Cambrian Brachiopoda (p. 122). 6. North American species of Ordo-\dcian Brachiopoda (p. 122). « 7. European species of Ordovician Brachiopoda (p. 123). " CAMBRIAN BRACHIOPODA. NORTH AMERICAN SPECIES. Geographic distribution of North American species of Cambrian Brachiopoda. Note. — The letters placed opposite each species in the various columns denote the State or province in which the species occurs: for instance, a "C" in column 2 under A indicates that the species occurs in Cape Breton, "CN" indicates that it occurs in hoth Cape Breton and New Brunswick. i § ■g & A .H V s CM A. B. C. D. Atlantic coast prov- ince. Appalachian prov- ince. Rocky Moun- tain province. Interior continental province. 1. 2. 3. 1:. 2. 3. 4. 1. 2. 3. 1. 2. 3. 4. 5. 6. 7. i .o 7, ■o . an dl 23 ft 5 1 « ■a d . si IS =! A I •A 1 o >< 1 > of . II i %a 'be . si 1 1 f A 1 =3 c3 1 •0 1 § .2 1 •A 0 § h a 1 1 •3 i i 03 B 0 i. 8 ■p, ! i g 1 1 1° dg T 0 0 Rustella edsoni Walcott B V p major (Matthew) A N Mickwitzia occidens Walcott C CN Micromitra alabamaensis (Walcott) B TA haydeni Walcott C I nisus (Walcott) B Q pealei (Walcott) CD M M A sculptilis (Meek) CD UN N w sculptilis endlichi Walcott C C B D Micromitra (Paterina) bella (Billings) AB BCD N .... M LQ V p T NU? N A iabradorica (Billings) ABC and Europe. B N N LQ N V B labradorica swantonensis (Walcott).. . Iabradorica utahensis (Walcott) C U N labradorica var. undt. (Walcott) C logani (Walcott) B Q major (Walcott) B A prospectensis (Walcott) C N stissingensis (D wight) BCD N B? B M? stissingensis ora Walcott C stuarti Walcott C U u superba (Walcott) CD M A C B B A Micromitra (Iphidella) louise Walcott C A * C M A and Eu- rope. ABCD N pannula (White) C? N GT B M lUN I lU A pannula maladensis (Walcott) pannula ophirensis (Walcott) AC C and China. N B " Only those taken up in this monograph. DETAILED GEOGRAPHIC DISTRIBUTION. 115 Geographic distribution of North American species of Cambrian Brachiopoda — Continued. Note The letters placed opposite each species in the various columns denote the State or province in which the species occurs; for instance, a"C" in column 2 under A indicates that the species occurs in Cape Breton, "CN" indicates that it occurs in both Cape Breton and New Brunswick. 2 m ft i o 1 A. B. c. D. Atlantic coast prov- ince. Appalachian prov- ince. Rocky Moun- tain province. Interior continental province. 1. 2. 3. 1. 2. 3. 4. 1. 2. 3. 1. 2. 3. 4. 5. 6. 7. i if 1 1 r s a 1 o ■s 1 1 O > IS . 3.2 a> s^ si si. T3 'gl J gs < T3 i o C3 a o 1 > =3 ^■ ■i >-< o z "S d C3 O "5 o T3 a 1 s . il a" '§ o 1 1 c3 a o O i d s o a .§ ■5 •d 0 C3 'is o « ^"° a'" _o "o O D M A c discoideas ( Hall and Wliitfield) frflpili'^ fWalcottl C, and Ord M lUN A N D M M V TG T B D C c BA M UNO NC UN N lU c c M B? and CD BCD, Chi- na?, and Ord. c V? V? 0 V M AVM M? 0 T w B D W WM D CD N B T c BA D W ■nrindlpi (Wa\cntt) B NV? A ON rhpa Walontt D WM BCD G M UN w A C c B D TA A M N w B CD M U u I A w c CD 0 A c B TGA c I .... .... D A c N B V A and Eu- rope. c c c Obolus (Palceobolus) bretonensis (Mat- thew). A Obolus (Fordinia) bellulus (WalcotV) c NU? U U N C .. c . Obolus (Acritis?) meatus Walcott c D WM D A D w plln fTTflll nnd Whitfipldl BCD TA B M lUN y w c A c D A Inhk Walrott C and Ord. BD UN N W N A D c lU N N? c CD M AN? J) WM s? 0 UN A... 0 c A B T bella fWalrottt A N N N R A billinssiana f Whiteavesi A hiitt<5i Walpott B A A c c N A c c A and Eu- rope? 116 CAJVIBRIAN BRACHIOPODA. Gepgraphic distribution of North American species of Cambrian Brachiopoda — Continued. Note. — The letters placed opposite each species in the various columns denote the State or province in which the species occurs; for instance, a"C" in column 2 under A indicates that the species occurs in Cape Breton, "CN" indicates that it occurs in both Cape Breton and New Brunswick. i o "3 03 1 fl s Ph A. B. C. D. Atlantic coast prov- ince. Appalachian prov- ince. Kocky Moun- tahi province. Interior continental province. 1. 2 3. 1. 2. 3. 4. 1. 2. 3. 1. 2. 3. 4. 5. 6. 7. ■6 d — .2 |> 5 1l ii (5(3 o a) ■V o .a « n d . zn C .a § a 6 1 & -a o 1 03 ii t- o -a cl ca d o 1 > is P 5 -'5b II 1 c3 ga s< i c d < d 11 o .2 +J m d C3 d o .14 o Z s o (S d O -13 § 1 il 1 o O d 1 a i .d _^ o s o a 1 -o i 1 •a is O 03 2 o ■3 o Lingulella— Continued. cuneola (Whitfield) D S A, Europe, Asia,and South America. B, C, D, and Ord. c c TGA B M INU N M WS dubia (Walcott) A, South America, and Eu- rope. N CN c flumenis (Matthew) B V NV hayesi Walcott B A CD M lU w ino fWalcottI B TG iris (Billings). B Q isse (Walcott) C B lUN N CN 0 Isevis grandis Matthew - A . leos fWalcottl B G A and Eu- rope. CN A manticiila fWhite^ C and Ord. A 1?UN N CN A D and Ord WMI W B A ora f Walcott") D M? 0 D WM D T A s Tihaon fWalcottl D WM C and D' UN A? B N c N B GA CN A C <;phncherti fWalcottI B N BCD TGA T NU? WM M 0 cs B D M T A C C C A A D T ■wpllpri CWalcottl B N D WMI W D A B... P V * Lingulella (Lingulepis) acuminata (Con- rad). B, C, D, and Ord. D. VN TA M UN ON WM" 0 T cws w A C C C C C C A A A .. A A c C D A A N B 1.... LQ N N whiteavesi Walcott B '.... 1 o Lingulella (Inngulepis) acuminata also occurs in Michigan. DETAILED GEOGRAPHIC DISTRIBUTION. 117 Geographic distribution of North American species of Cambrian Brachiopoda — Continued. Note —The letters placed opposite each species in the various coluiniis denote the State or province in which the species occurs; for instance, a "C ' in column 2 under A indicates that the species occurs in Cape Breton, "CN" indicates that it occurs in both Cape Breton and New Brunswick. E2 1 1 [a a . 1 1 A. B. C. D. Atlantic coast prov- ince. Appalachian prov- ince. Rocky Moun- tain province. Interior continental province. 1. 2. 3. 1. 2. 3. 4. 1. 2. 3. 1. 2. 3. 4. 5. 6. 7. '6 a a 1 ^ . :% o C gfq 1 -> g — Cl 1" 1 c5 'a a o 1 ■a o >* •a § o i > II It § of sa o d a < 1 .3 r s 03 1 1 -a ■i 13 1 0 Z ■a § .9 i a 0 -3 i 1 1 i 1 0 i 0 s s z ■0 § t 0 < 11 "o 0 Dicellomus appalachia Walcott nanus (Meek and Hayden) pectenoides (Whitfield) poUtus(Hall) prolificus Walcott B TA C, D, and Ord. CD M M WS M M w WM s BCD T u u N M s C B, C, and Asia. A LQ V B N C NC sp. undt. Walcott B V C M AB AB AB N N M G L LQ N VN crassa ( Hall) M P7 G? B minor ( Walcott) B N Po C A C Botsfordia caelata (Hall) AB .. - N N .... Q VN A B LQ Q? B andC?.. "'n'" P C? B Dearbornia cTarki Walcott C M C c Insignis Matthew A N N N CN A pristinus (Matthew) A... A C and Ord. C u N I C A C C avia puteis Matthew A bellula Walcott B A 0 BA M decipiens Walcott B P C N A... M matthewl (Hartt) A N N N N matthewi lata Matthew A A nitida (Ford) B N C M prima ( Matthew) A CN N C A N proles Matthew A C N lU N U NU? subsidua (White) C B C subsidua leei.'ls Walcott C C woodworthi Walcott.. A M B P sp. undt. a Walcott B Q Llnnarssonella girtvi Walcott minuta (Hall and Whitfield) CD U N U U u TJ U N UN s C and Ord. C modesta Walcott . . . C tennesseensis Walcott . BC. T C Urania Walcott C C attenuata Meek CD M M w C A N C U A CN ?? cancellata Walcott c N N claytoni Walcott C __; a This species also occurs in Virginia and Maryland. 118 CAMBRIAN BRACHIOPODA. Geographic distribution of North Amciicaii species of Cambrian Brachiopoda — Continued. Note. — The letters placed opposite each species in the various columns denote the State or province in which the species occurs; for a"C" in column 2 under A indicates that the species occurs in Cape Breton, "CN" indicates that it occurs in both Cape Breton i Brunswick. instance, and New xi B S A. B. C. D. Atlantic coast prov- ince. Appalachian prov- ince. Roclcy Moun- tain province. Interior continental province. 1. 2. 3. 1. 2. 3. 4. 1. 2. 3. 1. 9 o 1- B 2, 3. 4. 5. 6. 7. '6 a II 1 i| 1 S si 1 ;-■ o -a o3 i o >^ o S.2 P Ph g d S3 1 < d a ii t 1 1 1— 1 o id §1 1 o 1 o 6 H 8 1 i ■a § P o g Aero treta— Continued . concentrica Walcott B G c curvala Walcott C and D '* N IN 0? definita Walcott CD w depressa (Walcott) c B N gemmula Matthew j^ CN N idahoensis Walcott CD and Ord. c M lUN UN IV N ws idahoensis alta Walcott idahoensis sulcata Walcott c c inflata (Matthew) A N kutorgai Walcott B TA marjumensis Walcott c U N CD 0 T D M microscopica tetonensis Walcott D w A N N neboensis Walcott c U nox Walcott D yf ophirensis Walcott c U c u u N lUN C ophirensis rugosa Walcott c c primaeva Walcott c c U rudis Walcott B T sagittalis (Salter) A, B, and Europe. N N N Q BC N B sagittalis transversa (Hartt) A N cf. sagittalis c U signahs Walcott D w spinosa Walcott c N ulrichi Walcott D sp. undt. Walcott A C C I proavia (Matthew) A C c c c c N A signata Matthew A A signata prima Matthew A A C B B B Nisusia alberta Walcott . . C U festinata (Billings) BC LQ VN V P festinata transversa ( Walcott) , . B rara Walcott c I Nisusia (Jamesella) amii Walcott B Q argenta Walcott c N N c ? kanabensis Walcott D lowi Walcott c B B7 nautes (Walcott) c IU7 lU u c utahensis Walcott. 0 B L A N N A Ifpvis Walcott D w latourensis (Matthew) A N N A B V D Protorthis (Loperia) dugaldensis Walcott. A CN B A T B inyoensis Walcott C c ;;■;;;;!_; DETAILED GEOGRAPHIC DISTRIBUTION. 119 Geographic distribution of North American species of Cambrian Brachiopoda — Continued. Note.— The letters placed opposite each species in the various columns denote the State or province in which the species occurs; for instance, i"C" in oolmnn 2 under A indicates that the species occurs in Cape Breton, "CN" indicates that it occurs in both Cape Breton and New 1 o s ft 1 1 .S v g p-l A. B. C. D. Atlantic coast prov- ince. Appalachian prov- ince. Eocliy Moun- tain province. Interior continental province. 1. 2, 3. 1. 2. 3. 4. 1. 2. 3. 1. 2. 3. 4. 5. 6. 7. '6 1 21 cqcq 1 t3 o r i 1 > ■S.2 m Si i-< - < 1 3 03 0 o lie h-1 o ■3 g o O C3 o 1=1 c6 1 o i C3 1 o 6-1 8 X S q] c3 CI o < 1 |1 5 Wimanella — Continued . saflordi (Walcott) B T A slielbyensis Walcott B. C B M Biliingsella? appalachia Walcott B TG bivia Walcott C c lU NC coloradoensis (Shumard) ACD and Ord. C N B M WM M T w highlandensis (Walcott) D W M? marion Walcott C B D A orientalis (Whitfield) B... V plicatella Walcott C M w retroflexa (Matthew) A... C B Q N striata Walcott C M Whitfield! (Walcott) C N N N Orusia? eurekensis (Walcott) C A, C, Sout In Ameri- ca, and Europe. A N CN N N A Otusia sandbergi ( Winchell) D M C M U Eoorthis atava (Matthew) A desmopleura (Meek) B, C, D, and Ord. D and Ord. D. P B M U N w w ? diablo (Walcott) W hastingsensis (Walcott) A iddingsi (Walcott) D... . T T w indianola (Walcott) D M jnhannpn.sis (Afattbpw) A C u newtone'nsis (Weller) B papias (Walcott) A N CD M u? WM WM w D CD M M T rpmninh?!, wiiiflplrlp.nRis (Walnntt) D. W C u 0, D, and Ord. D M M 0 0 T T w zeno Walcott C u Finkelnburgia finkelnburgl (Walcott) osceola ( AValcott) D WM WM WM D. D B V weeksi Walcott. C N D barabuensis (A. Winchell).. D W C u namphplli Wnlnntt B... T C and Ord. D u WM M 0 w primordialis argia Walcott . D. D w ? unxia Walcott C u CD M w billingsi ( Walcott) B V lesleyi (Walcott) C u D T T texana Igeviusculus (Walcott) D vermontana Walcott B... V 120 CAMBRIAN BRACmOPODA. EUROPEAN SPECIES. Geographic dhtrihulion of European species of Cambrian Brachiopoda. Note. — The letters placed opposite each species in the various columns denote the country or province in which the species occurs; for Instance, in the third column an "b" indicates that the species occurs in Sweden, "SF" indicates that it occurs in both Sweden and Finland, etc. Eng- land, Scot- land, Ireland, and Wales. Nor- way, Swe- den, Den- mark, and Fin- land. Russia and Poland. Prus- sia. Bohe- mia. Bava- ria. France. Sar- dinia. Spain and Por- tu- gal. Also occurs in— Mirlm-it/in fnrmn'^a (Wimnn) SF SF S mnnilifprj^ { T,JTinHfS''nTi) E pretiosa Walcott ?sp. undt. Walcott S Miprnmilrn, pnsill:^ rT.innars.'^nn) E S E E SD philUpsi (Holl) r.: nn(in,«yi /Afnhprp^ , S SD Micromitra I Iphidella) omatella (Linnarsson) Volborthia recurva (Kutorga) R R EP R R R Obolus apollinis Eichwald SF P apnIIinisTn;i\-iTnniscinopsis? sulcatus AValcolt., Eillingsella pumpellyi \\'alcott- richthofeni Walcott Wynnia wartlii (Waageu) Eoorthis agreste (Walcott) doris (Walcott) kayseri (Walcott) kichOLiensis (Walcott) linnarssoni ( Kayser) pagoda (Walcott) sp. undt. Walcott Syntrophia orthia Walcott Huenella orien talis (Walcott) . . . X X X X X X X X X SOTTTH AMERICAN SPECIES. South Ameiican species of Cambrian Brachiopoda. Obolus sp. undt. e Kayser " Argentina. Lingulella davisi (McCoy) Do. feiTuginea Salter Do. Orusia lenticularis (Wahlenberg) Do. Eoorthis saltensis (Kayser) « Do. AUSTRALIAN SPECIES. Australian species of Cambrian Brachiopoda. Micromitra (Paterina) etheridgei (Tate) South Australia. Kutorgina peculiaris (Tate) Do. Obolella wirrialpensis Etheridge Do. Nisusia compta (Tate) --- Do. Eoorthis tatei (Etheridge) Do. Huenella etheridgei Walcott Do. ORDOVICIAN BRACHIOPOBA. NORTH AMERICAN SPECIES. Geographic distribution of North American species of Ordovidan Brachiopoda. General location. Occurrence in Cambrian. b Obolus anceps "Walcott belli (Billings) cyane (Billings) discoideus (Hall and Whitfield). dolatus (Sardeson) matinalis (Hall) ? murrayi Billings. . .1 rotundatus (Walcott) sp. undt. a sp. undt. c Obolus (Lingulobolus) affinis (Billings). spissus (Billings) Obolus (Westonia) elongatus Walcott. iphis Walcott notchensis Walcott rogersi Walcott Lingulella bella (Walcott). desiderata (Walcott) ellsi (Walcott) j^randis (Matthew) lole (Billings) Irene (Billings) manticula (White) niosia (Hall) Lingulella (Lingulepis) acuminata (Conrad), acuminata sequens Walcott Nevada Quebec Newfoundland . Utah Minnesota Colorado Newfoundland Nevada New York Nevada Newfoundland and Massa- chusetts. do Utah Nevada Utah Massachusetts, Rhode Island, and Newfound- land. Newfoundland and Bhode Island. Colorado Quebec New Bruns^vick. Newfoundland Quebec Nevada Minnesota New York ...do B, C, D'-, D<, D5, and D', and China. B and C. C. B, C, D3, and D'. C. B, C, Di, D2, D<, D5 and D'. o Identified from South America only. 6 See table on pp. 114-119. DETAILED STEATIGRAPHIC DISTRIBUTION. 123 Geographic distribution of North American species ofOrdovician Brachiopoda — Continued. General location. Occurrence in Cambrian.a Elkanla ambigua ( Walcott) desiderata (Billings) ida (Billings) Dicellomus nanus (Meek and Hayden) Schizambon manitouensis Waleott typicalis Waleott Acrothele levisensis Waleott ' pretiosa (Billings) Linnarssonella niinuta (Hall and Whitfield) . Acrotreta gemma Billings idahoensis AValcott ovalis Waleott BiUingsella coloradoensis (Shumard) dice (Waleott) Eoortbis desmopleura (Meek) desmopleura nympha (Waleott) ■niehitaensis (Waleott) Syntrophia calcifera (Billings) lateralis (Whitfield) nundina Waleott -Clarkella montanensis (Waleott) Nevada Quebec do Wyoming Colorado Nevada Quebec Quebec and New York Nevada Newfoundland Nevada Quebec Minnesota Vennont Colorado and Utah Colorado do Quebec and Newfoundland. . Vennont Nevada. Utah, and Colorado. Montana C, D3, and D^. C. C. C and D7. A,C,D2,D3,D^and D^. B,C, D6, and D^. C, D3, DS D'\ and D^ a See table on pp. 114^119. EUROPEAN SPECIES. Geographic distribution of European species of Ordovician Brachiopoda. General location. Also occurs in — Volborthia recurva (Kutorga) Obelus? advenus Barrande ?ancillus (Barrande) complexus Barrande feistmanteli (Barrande) ? mirandus (Barrande) ? rokitzanensis Barrande Obolus? (Westonia?) lamellosus (Barrande). Lingulella davidsoni (Barrande) davisi (McCoy) heberti Barrois ? insons ( Barrande) ? simplex (Barrande) Siphonotreta unguiculata (Eichwald) verrucosa (Eichwald).. Acrotreta babel Barrande. ? minima ^Barrande) . nicholsoni. Davidson. . . Eubconica Kutorga Eussia Bohemia ....do ....do ....do ....do ....do .»..do do England Spain Bohemia do Russia, and East and West Prussia. do Bohemia do Scotland and Ireland Russia Upper Cambrian. Passage beds (Russia). Do. Upper Cambrian. DETAILED STRATIGRAPHIC DISTRIBUTION OF CAMBRIAN AND ORDOVICIAN BRACHIOPODA. The following table includes, arranged alphabetically by States or countries, more or less detailed information concerning the stratigraphic distribution of the different species of Cam- brian and Ordovician Brachiopoda. The data available for the foreign species were not sufficient to warrant greater detail than that secured by the use of generalized sections, and there has been no attempt to keep the species from any one section in a distract column. Doubtful correlations are indicated by a question mark after the locality number. For some of the regions in North America typical fossiliferous sections have been intro- duced, giving in an adjoining colunui the species collected from the various horizons in the section and in a third column the species collected at other places in the same general area. In such tables the stratigraphic arrangement of the second column is fairlj^ accurate; that of the third may contain errors iir correlation and must be regarded as merely approximate. Each specific name is followed by the number of the locahty at which it occurs, and the fist of localities on pages 161-291 will furnish the student with all known information as to the association and the stratigraphic and geographic position of the species in question. The numbers of the different locahties identified from a given formation. State, country, or place may be found by referring to the index. 124 CAMBRIAN BRACHIOPODA. Detailed stratigraphic distribution of Cambrian and Ordovician Brachiopoda."' Alabama. See Tennessee, Georgia, and Alabama, where the liorizons are more or less closely differentiated and correlated, with complete lists of localities and included species. Alberta. See British Columbia: Mount Bosworth section, where the Alberta localities are shown in their approximate stratigraphic position. Arizona. One of the Arizona localities (75) has been assigned to the Upper Cambrian; 74b occurs high up in the Tonto group, but has been entered as Middle Cambrian; and the remainder (see index for numbers) occur at various more or less closely related horizons in the "Tonto" sandstone. Bohemia. Section. Localities and species. ORDOVICIAN. Etage d4 303m, 303n, 303o. Lingulella davidsoni— 203m, 303n, 303o. LOWEK 0RD0VICU.N. Etage d3 303, 303a, 303p. Linguldlaf simplex— ZOZa, 303p. Acrotreta babel~303, 303a. Etage dl - . .'. i 303b, 303d, 303e, 303g-l. Obolusf adiifjlMs— 303d. Obolusf andnus—303g. Obolusf complexus—303g, 3031i, 3031. Obolus feistmanteli—303i, 3031 Obolus mirandus — 303k. Obolus rokitzanensi.s—303l>. Obolusf (^Westonia?) lamellosus— 3031. Lingulella insons— 303d, 303e. Lingula f eximia—303 1. Acrotreta? minima 303d. PASSAGE BEDS. 303c, 303f. Obolus bamricus— 303c. . ^ Obolus minor — 303c. Obolus palliatus— 303c. Lingulella cedens— 303c, 303f. Lingulella humillima— 303c, 303f. Lingulella siqnata — .303c. Lingulella wirthi— 303c , 303f. Lingula a. sp.— 303f. Acrotreta inclioans— 303c, 303f. Acrotretan. sp.— 303f. Orbiculoidea contraria— 303c, 3031. Orbiculoidea varians—303c, 303f. Eoorthis bavarica—303c, 303f. (See 3031, p. 235, lor associated forms other than brachiopods.) MIDDLE CAMBRIAN. 345bT, 345c, 346f, 345g, 345h, 3451. Acrottielc bohemica — 345b, 345c. Nisusia (Jamesella) kuthani— 345!. Billingsella romingeri—3ioc, 3451, 345g, 3451i, and 3461. Paradoxides zone (see Etage C) 345, 345a, 345d, 345e. Lingulella cf . ferruginea — 345. Acrothele bohemica— 3i5, 345a. Acrothele quadrilineata — 345d. Billingsella romingeTi—3i5. Eoorthis sp. undt. a — 345. Eoorthis sp. undt. b— 345e. (See 345, p. 270, for additional forms.) LOWER CAMBRUN. 3451, 345], 345kl. Nisusia (Jamesella) lcuthani—345[, 345j, 346k. Nisusia (Jamesella) perpasta — 346i, 34.5J, 346k. Nisusia {Jamesella) perpasta macra—3io\, 346j. Nisusia (Jamesella) perpasta subquadrata—3ib\, 345j. o For complete lists of the localities in each State, country, formation, etc., see index. DETAILED STKATIGEAPHIC DISTRIBUTION 125 Detailed stratigraphic distribution of Cambrian and Ordovidan Brachiopoda — Continued. British Columbia: Mount Boswoith, Mount Bosworth section. [Waloott, 1908f, pp. 204-217.] Localities and species in the Mount Bosworth section. Other localities and species In British Columbia and Alberta shown in their approximate stratigraphic position. The Mount Bosworth section is exposed north of Hector, British Columbia, on the Continental Divide north of the Canadian Pacific Railwaj^. The general dip of the strata is to the northwest 20°; strike, N. 30° E. The section is continuous except for the displacement between the Paget and Bosworth formationscf the Upper Cambrian. That thisdoesnotcut out any con- siderable thickness of strata is proved by tlie unbroken section in the cliffs of Mount Daly 3 miles to the north. Only the upper part of the St. Piran sand- stone is exposed on Mount Bosworth; the remainder of the section shown on pages 131 and 132 was measured in the vicinity of lakes Louise and Agnes, nearly 5 miles to the southeast. The summit of the section is on the west spur (Sherbrooke ridge) of Mount Bosworth overlooking Sherbrooke Lake. The highest beds are on the south sum- mit of the ridge, and from their lithologie character and the presence of obscure fossils that suggest OphUcta of the Lower Ordovician the upper 110 feet of strata is tentatively referred to the Ordovician system.i The strata near the summit are much broken up owing to a fault line that crosses the ridge. OEDOVICIAN.a 1. Massive-bedded gray and bluish-gray arenaceous limestone, with Feet. thin layers, irregular stringers, and nodules of dark chert 110 UPPER CAMBRIAN. Sherbrooke limestone [Walcott, 1908a, p. 2]: 1. Massive-bedded bluish-gray limestone, with some cherty matter in the form of small nodules and stringers; also irregular partings and fillings of annelid borings by gray dolomitic limestone, Annelid borings and trails. Fragments of undetermi- nable trilobites. 2a. Gray oolitic limestone in thick layers, with bluish banded limestone intercalated at irregular inten^als. The banded appearance of the nonoolitic layers is owing to the buff- weathering of the thin dolomitic layers 190 Crepicephalus. Pierocephalia ?. Ptyehoparia. 2b. Greenish-drab and gray siliceous shales with interbedded oolitic limestone in bands of layers from 6 inches to 4 feet thick; also a few bands of thick-bedded bluish-gray lime- stone that breaks up into shaly limestone on weathering. . 335 S7d, 68f. In green shales near sum- mit: Lingulella isse — 57d. In oolitic layers: Agnostus sp. undt. Illsenurus. Ptyehoparia. In limestone: Obolus sp.— 58f. 2c. Gray oolitic limestone with thin bands of interbedded shaly blue-gray limestone. Gray dolomitic buff-weather- ing flattened nodules, stringers, and thin layers of lime- stone oncnr in a very irregnlnr miinner fi.^ Illienmus. Agnostus. Ptyehoparia. Bathyurus-likfi pygidia. 590 3. Arenaceous dolomitic steel-gray limestone, weathering light gray and buff gray 610 The line of demarcation between 3 and the bluish-gray lime- stones below is irregular. The gray beds of 3 extend along the cliff and abruptly change to bluish gray. In tlie upper 100 feet of 3 irregular masses of bluish-gray limestone occur like great lentiles, as though they were cores left in the general alteration (dolomitization) of the strata. Total of Sherbrooke limestone 1 , 375 Paget limestone [Walcott, 190Sa, p. 3]: 1. Massive-bedded dark bluisli-gray limestone forming base of cliff on the west side of the amphitheater on the west slope of Mount Bosworth and, with 3 of Sherbrooke limestone, the upper cliffs 2. Massive beds of oolitic limestone with irregular interbedded bands of green siliceous shale. Tliin layers, irregular stringers, and nodules of gray buff-weathering dolomite occur in the oolitic limestones 300-1- Base covered by talus slope on line of the section. It is well ex- posed on the southeast face of Mount Daly and Paget Peak. The thickness is placed at 300 feet, which I think is less than the total thjckness. Over 200 feet was measured. Hyolithes. Agnostus. Crepicephalus. Total of Paget limestone 360-1- a During the field season of 1911 these beds were examined by Mr. J. A. Allan and Mr. L. D. Burling, who found, in the uppermost portion, fossils similar to those in 26 of the Sherbrooke limestone. This made it possible to place between the new Sherbrooke and the true Ordovician a series of nearly 4,000 feet of Upper Cambrian shales and limestones referred by Mr. Allan to the Chancellor and Ottertail formations, respec- tively. (See Walcott, 1912, Smithsonian Miscellaneous Collections, vol. 57^ No. 7, pp. 229-231.) 126 CAMBKIAN BRACHIOPODA. Detailed stratigraphic distribution of Cambrian and Ordovician Brachiopoda — Continued. British Coliunbia: Mount Bosworth— Continued. Mount Boswortti section. [Walcott, lOOSr, pp. 204-217.] Localities and species in the Mount Bosworth section. Other localities and species in British Columbia and Alberta shown in their approximate stratigraphic position. UPPER C.4MBEIAN— continued. Bosworth formation [Walcott, 190Sa, p. 3]:o 1. Massive-bedded gray and bluisli-gray arenaceous dolomitic lime- stone. Several bands of steel-gray, yellowish bull-weathering Feet. This formation forms the base of the high clifls on the southeast face of Mount Daly and Paget Peak. The lower portion of 1 was measured and the upper parts esti- mated. The thickness given is probably 100 feet or more less than the actual thickness. 2a. Shaly and thin-bedded gray and dove-colored, compact, fine- grained dolomitic limestone weathering bull and light gray. Thicker layers occur in bands from 1 to G feet thick 422 26. Greenish siliceous shale with thin interbedded layers of sili- ceous, compact, gray limestone 48 At about this horizon in the Cas- tle Mountain section, 20 miles southeast of Mount Bosworth, small trilobite heads of the genera Ptychoparia and Soleno- plcura occur in a band of gray and bluish-black limestone, and, just below, fragments of a species of Obolus. 2c. Limestones similar to 2a 517 9S7 3. Variable arenaceous shales with alternating bands of color— green- ish, deep red, buff, yellow, and gray 26S Numerous mud cracks and ripple-marks occur on many of the layers. Total of Bosworth formation . l,S55-(- Total Upper Cambrian 3, 590-1- MIDDLE CAMBRIAN. Eldon limestone [Walcott, 190Sa. p. 3]: la. Irregularly bedded gray siliceous and arenaceous limestone in thick layers above arid thin layers below; at 192 feet from the base a bed of bluish-black liraestone is fossiliferous. Above the fossiliferous bed the strata become more massive, arena- ceous, steel gray in color, and weather to a light gray 410 192 feet above the base: Agnostus sp. Ptychoparia, 2 species. Bathyuriscus-l\k& pygid- ium. 16. Light and dark gray thin-bedded arenaceous limestone weath- ering light gray 110 Ic. Massive-bedded siliceous, fine-grained, compact, dark bluish-gray limestone 197 Two yellowish buff-weathering bands of limestone 2 to 3 feet thick stand out in color on the face of clifls. Near the summit: Billingsella? JVcoienus-like pygidium. 788 2. Thin-bedded bluish-gray limestone with irregular layers and stringers of gray buff-weathering dolomitic limestone 95 3Sg. In shaly limestone: Oiolus mcconnelU var.— 35g. Obolus memhranaccus — 35g. Isoxys cf. argentca — 35g. Ptychoparia, 3 species— 35g. At 24 feet from the base a shaly bluish-gray siliceous limestone about 2 feet thick is interbedded. 3. Massive-bedded dark-gray arenaceous limestone 190 a This formation reminds me, in lithologic character and appearance, of strata of the upper portions of the Algonkian Belt series of Montana. No traces of life were observed and the shaly, banded character of the beds is very striking. DETAILED STRATIGRAPHIC DISTRIBUTION. 127 Detailed stratigraphic distribution of Cambrian and Ordovician Brachiopoda — Continued. British Columbia: Mount Bosworth— Continued. Mount Bosworth section. [Waloott, 1908f, pp. 204-217.] Localities and species in the Mount Bosworth section. Other localities and species in British Toliunbia and Alberta shown in their approximate stratigraphic position. MIDDLE CAMBRIAN— continued. Eldon limestone— ContiTmed. 4. Massive-bedded cliff-forming light-gray arenaceous limestone. At several horizons bands of thinner layers from a few feet up to 30 feet in thickness occur. One of these 4S0 feet from the base forms Feet. a slight terrace 1, 655 57n. In the Mount Stephen section, 7 miles southwest of Mount Bosworth, at a horizon about 700 feet above the base of this limestone, the following fossils have been recognized : Pratospongia (spicules)— 57n. Lingulella cf. isse — 57n. Hyolitlies sp.— 57n. Agnostus cf. montis — o7n. Zacanthoides spinosus — 57n. Ftychoparia sp. — 57n. Bathyuriscus sp.— 57n. Ogygopsis sp.— 67n. Total of Eldon limestone 2,728 Stephen format ion [Walcott, 1908a, p. 3]; 57c, 57k. Micromitra zcnobia—olc. Obolus mcconnelli—o7Cf57k, Nimsia alberta var.— S7c,57k. Hyolitlies carinatus — 57c. ^^nos/us sp.— 67k. Agraulos sp. — 57k. Menocephalv,s sp.— 57c. Ptychopariaj 3 species — 57c, 57k. Ncolcnus sp. — 57c, 57k. Bathyuriscus sp. — 57c. 35k,o 57f, 57j, 58i, 5Sj, 58r, 58w. .Wcromitra(Patcriiia)stissingcnsis ora — 35k. Micromitra (.Iphidella) pannula— 35k, 57j. Obolus mcconnelli — 57f, 5Si, oSi, 5Sr, 58w. Acrothcle subsidua — 58i. Acrotreta depressa—5H, 58j, ,58r. Nisusia alberta — 35k, 57j. Nisusia (Jamcsella) cf. nautes— 57f. (See 35k, 57f, 57j, 5Sj, and 58r, pp. 198 and 207-210, tor addi- tional associated forms.) ♦ 14s. At Mount Stephen, about 7 miles southwest of Mount Bosworth, a siliceous shale b occurs at the summit of the Stephen forma- tion, in which the following unusually rich fauna occurs: Hyolithcllus fiagellum (Mat- thew) [1S99, p. 40). Hyolithellus annulatus (Mat- thew) [1S99, p. 42]. Or//(o//ifca corru^Qia Matthew (1899, p. 42]. Orthotheca major Walcott 11908c, p. 24C,"P1. I, fig. 11]. Hi/oUthcs carinatus Matthew [1899, p. 42]. Uyolithcs sp. Stenotheca wheeleri Walcott [190Sc,p.245, PI. I,fig. 7]. Platyceras rominger Walcott (1SS9C, p. 442]. Platyceras bellianus Walcott (1908c, p. 24li, PI. I, fig. 13]. Acrotreta depressa (Walcott) (1889c, p. 441]. Micromitra (Iphidella) pan- nula (White) [1874, p. 6]. Obolus mcconnelli (Walcott) [1889c, p. 441). Obolus septalis Walcott [1905a, p. 331]. Nisusia alberta Walcott (lS89c, p. 442], Philhedra columbiana (AVal- COtt) [18890, p. 441]. Scenella variant Walcott [1886b, p. 127]. o Thk is the locality containing the beautifully preserved annelids, medusae, holothurians, crustaceans, etc., now being described and illus- trated in volume 57 of the Smithsonian* Miscellaneous Collections. b The name Ogygopsis zone is applied to the local development of arenaceous and calcareous shale at the summit of the Stephen formation on the northwestslope of Mount Stephen. The shale band (lentile) has a maximum thickness of about 150 feet. It thins out to the northeast and is faulted outto the southwest. At its maximum thiclmess, 2,800 feet abave Field, it carries immense numbers of trilobites. especially Ogygopsis klotzi (Rom- ingev) fBatht/uriscas rotunditus (Rominger), Neolenus serratus (Rominger), Zacanthoides spinosus (Walcott), and, in addition, sponges, cystids, bracluopods,pteropods, and gastropods. The shale is less rich in fossils one-fourth mile northeast on the strike; also to the northwest. Lentiles of grayquartzitic sandstone and siliceous gray limestone occur in the shale, and the entire band appears to be a lentile between the thin-bedded blue limestones and the superjacent massive arenaceous limestone formation. There is no trace of the Ogygopsis zone at the same horizon on Castle Moimtain 20 miles east-southeast. On Mount Field it is represented by the Burgess shale. Locality 35k. There is a sharp anticline, with a northeast-southwest axis, in the shale and the thin-bedded "limestones beneath, on the northwest slope of Mount Stephen. The southeast limb is crushed and the beds are largely faulted out against the massive arenaceous limestone before reaching the amphitheater at the head of Field Brook. On the northwest limb the shales are unaltered and slope down the side of the mountain for 1,800 feet, thus affording a great exposure of the shale and contained fossils. 128 CAJMBRIAN BRACHIOPODA. Detailed stratigraphic distribution of Cambrian and Ordovician Brachiopoda — Continued. British Columbia: Mount Bosworth— Continued. Other localities and species in British Columbia and .Mberta Mount Bosworth section. Localities and species in the IWalcott, 1908f, pp. 204-217.] Mount Bosworth section. shown in their approximate stratigraphic position. MIDDLE CAMBUTAN— continued. Stephenformation—Contmaed. 14s— Continued. A nomalocaris canadensis Whiteaves |1S92, p. 207]. Anomalocaris? wititeavcsi Wal- cott [190SC, p. 24(i, PI. II, figs. 2, 2a, 4, 0, and 6a]. Anomalocaris?? acutangula Walcott [1908c, p. 247, PI. II, flg. 5]. Agnostus mantis Matthew [lS99,p. 43]. Vorypyge (Kootenia) dawsoni (Walcott) [1S89C, p. 44(i]. Bathyuriscus rotundatus (Rominger) [1SS7, p. 16]. Bathyuriscus pupa Slatthew [1S99, p. 51] probably= Bathyuriscus occidentalis. Bathyuriscus occidentalis (Matthew) [1899, p. 49]. Bathyuriscus ornatus Walcott [1908b, p. 39]. Karlia stephenensis Walcott [1889e, p. 445]. Coryneiochus romingeri Mat- thew [1S99, p. 'n]=Earlia stephenensis. Neolenus scrratus (Rominger) [1887, p. 13). Neolenus granulatus Matthew [1899, p. 55]= Neolenus ser- ratus. Ogygopsis Ulotzi (Rominger) [1887, p. 12]. Oryctocephalus reynoldsi Reed [1899, p. 359]. Oryctocephalus walkeri Mat- • thew [1899]= Oryctocephalus reynoldsi. BuTlingia hectori Walcott [1908b, p. 15]. Ptychoparia cordillerse (Rom- inger) [1887, p. 17]. Conoccphalites cf. pcrseus Hall, Matthew [1899, p. 46] = Ptychoparia cordillcrx. Ptychoparia palliscri Walcott [190Sc,p. 247,P1. III,flg.6]. Zacanthoidcs spinosus (Wal- cott) [1884, p. 63]. Feet. 67y. 2a. Greenish siliceous shale 23 Oiolus OVestonia) dlaf—Slj. SSz. 2b. Thick-bedded bluish-gray limestone, breaking up into thin Micromitra zenobia— SSz. layers h to 3 inches thick on weathering 22 Nisusia alberta var. — 582. Mcnocephalus — 5Sz. Ptychoparia^dSz. Neolenus— SSz. 2c. Greenish siliceous shale 70 57g. 981. 2d. Alternating bluish-gray bedded compact limestone, siliceous Cnizianu. On Mount Stephen, at a horizon and arenaceous shale, mostly shale below 210 Micromitra {Iphidella) pan- 150 feet from the base of this 325 Tiula — 57g. limestone, the fauna includes: Obolus ( Westonia) ella—57g. HyoHthes—Slg. Hficroiititra zcnobia — 58 1 Total of Stephen formation 640 Livgulclla desiderata— 5S 1. Lepcrditia—blg. Billingsella marion—bSl. P(j/cAoparia— 57g. Hyolilhes—5S 1. Bathyuriscus — 57g. Microdiscus—5S 1. Ptychoparia — 58 1. Cathedral limestone [\Yalcott, 1908a, p. 4]: la. Thin-bedded gray to lead-gray arenaceous limestones, weathering bufE ?rav to dull lie^ht srav 404 1&. Massive-bedded steel-gray weathering light-gray arenaceous lime- stone. In some localities thinner layers appear at various hori- zons and large lentiles of dark lead-gray colored beds occur very irregularly 682 DETAILED STRATIGEAPHIC DISTKIBUTION. 129 Detailed stratigraphic distribution of Cambrian and Ordovician Brachiopoda — Continued. British Columbia: Mount Bosworth— Continued. Other localities and species in Mount Boswortli section. Localities and species in the British Columbia and .Vlberta [Walcott, 1908f, pp. 204-217.) Mount Bosworth section. shown in their approximate stratigraphic position. MroDLE CAMBRIAN— continued. Cathedral limestone— Conthmed. Ic. Similar to la. Annelid borings and trails occur in and on some of Feet. the layers 12() Id. Similar to 16 S3 le. Thin-bedded lead-gray to blue-gray thin-bedded (layers 1 inch to 4 inches thick) arenaceous limestone 25 If. Alternating thin and massive bedded arenaceous steel-gray iime- stone weathering light gray 275 - 1,595 Total Middle Cambrian 4,963 I.OWEK CAMBRIAN. Mount WhiHe formation [Walcott, 1908a. p. 4): The line between the IRddle and Lower Cambrian is placed at this horizon on account of the presence in the Mount Stephen section of OleneUus in the limestone IIG feet below the massive arenaceous limestone belt represented by 1/ln the Cathedral limestone of the Motmt Bosworth section. la. Thin-bedded bluish-gray slightly arenaceous limestone 120 Numerous annelid trails and borings. 57s. S7m, S8k, 68p, 58t. 16. Gray oolitic limestone in layers 3 to 6 inches thick 44 Acrotreta sagittalis taconica— 67s. In the Mount Stephen section the following species occur at a Nisusia (Jamesella) lowi— horizon near the top of this 57s. limestone (58k and 58p) : Microdiscus sp. undt.— 57s. Acrotreta sagittalis taconica — Agraulos sp. — 57s. 68k. Ptychoparia sp.— 57s. Nisusia alberta var. — 58k, 58p. Nisusia (Jamesella) lowi— 5Sk, 5.8p. Stenotheca elongata var.— 58k. Scenella varians^oSk. Platyccras n. sp. — 58k. HyolitJies biUingsi — 58k, 58p. Fiychoparia sp. — 58k, 5Sp Crepiceptialus n. sp. — 58k. Frolypus n. sp.— 5Sk. AlhcrtcUa sp. undt. — 5Sk. At Castle Moim tain Ofto/Ksparfus occurs at about this horizon (58t). About 50 feet do^vn in the Mount Stephen section, in a gray sili- ceous shale, the following spe- cies occur (57in) : Cystid plates — 57m. Micromifra (Paterina) sp. undt.— 57m. Acrotreta sagittalis taconica — 57ra. Nisusia (.Jamesella) lowi — 57m. JTyolitltes (fragment) — 57m. Hj/oliihcllus cf. micans — 57m. SceneUa varians — 57m. OleneUus canadensis — 57m. 57e, 57r, 58s. Ic. Massive layers made up of banded bluish-gray limestone and Agraulos sp. imdt. On Mount Stephen, at a horizon sandstone in layers 4 inch to 2 inches thick, CO 224 near the top of this bed of lime- stone, there was found (57e): AcTothele colleni — 57e. Acrotreta sagittalis taconica— 57e. Scenella varians — 57e. Stenotheca elongata var. — 57e. Albertella sp. undt. — 57e. OleneUus canadensis — 57e. Bathyuriscus sp. undt. — 57e. Near the base on Mount Stephen (57r, 68s): Micromitra (Paterina) labra- dorica var. — 57r, 58s. Micromitra (Tphidella) pan- nuja^hlv, .58s. Acrotreta sagittalis taconica — 57r, 58s. Ptvchoparia, 3 species— 57r, 58s. 62667°— VOL 51, pt 1—12- 130 CAJMBRIAN BRACHIOPODA. Detailed straiigraphic distribution of Cambrian and Ordovician Brachiopoda — Continued. British Columbia: Mount Bosworth— Continued. Other localities and species in Mount Bosworth section. Localities and species in the British Columbia and .\lberta [Walcott, WOSt, pp. 201-217.) Mount Bosworth section. shown in their approximate stratigraphic position. LOWER CAMBRUN— continued. Mount \Vhyte formation — Continued. Feet. 2. Gray and brownish-gray sandstone in thin and massive layers 31 Hyolithes. On Mount Stephen, at this hori- Agraulos. zon, there were found: Microdiscus sp. undt. Olenellus sp. undt. (frag- ments). Ptyctioparia sp. undt. Protypus sp. undt. 35c. 35e. 3. Siliceous shale with a few interbedded thin layers of compact hard On the south slope of Mount In the Lake Agnes section, 5 miles gray sandstone 115 Bosworth two drift blocks southeast of Mount Bosworth, of siliceous shale, supposed the fauna of about this horizon to be from this horizon, includes : were found, from which Micromitra {Paterina) the following species were wapta—35e. collected: Oiolus parvus— 35e. Micromitra (Paterina) Hijolithes Ullingsi—35e. ■ wapta—ibc. Olenopsis n. sp.— 35e. Obolus parvus — 35c. Pii/chopariay 3 species. — 35e. AcrotMe colleni— 35c. Albertclla sp. vmdt.— 35e. Wimandla simplex — 35c. Bathyuriscus— 35e. Agraulos sp.— 35c. Olenellus gilberti—35e. Pit/clioparia sp. — 35c. On Mount Stephen, at about the Albcrtcllahoswortlii — 35c. same horizon, the following A Ibertella lielena— 35c. were found: Bathyuriscus sp. — 35c. Hyolilhes billingsi. Scenella variants. Olenopsis n. sp. 3Sh. 35f. 4. Interbedded layers of gray fossiliferous limestone and greenish-gray Nisusiafestinata—3Sh. At this horizon on Mount , siliceous shale 20 Sccncila variant — 35h. Stephen the following were found: \ .................. Hyolithellus—35h. Ptydioparia — 35h . Micromitra {Iphidella) pan- Agraulos — 35h. nula -35f . Protypus n. sp.— 35h. Kutorgina cingulata — 35f. Olenellus canadensis— 35h. Kutorgina sp. undt.— 35f. Total of Mount Why te formation 390 Olenellus gilberti—35h. Acrotreta sagittalis taconica — 36f. Nisusia festinata—35t. Hyolithes billingsi— 35t. Scenella varians—35f. Protypus n. sp. — 35f. Agraulos sp. undt.— 35f. Ptyctioparia, 3 sp. undt. — 35f. Olenellus canadensis— 351. Bow River group. St. Piran sandstone [Walcott, 190Sa, p. 4): la. Siliceous and arenaceous greenish-colored shales in layers 1 to 3 inches in thickness interbedded in shaly and thin-bedded gray and browTiish-gray sandstone, with a thick layer of compact gray sandstone near the top 68 60b. lb. Irregularly bedded bro\\Tiish, dirty-gray, and occasionally Annelid trails and borings Obolclla vermilionen.'iis—QOh. purplish-colored sandstones, more or' less compact and (Scolithus). Wanneria gracitc — GOb. quartzitic. in massive and thin layers that break down read- HyolilJtes. ily on slopes 310 Olenellus canadensis?. Ptyctioparia, 2 species. Ic. Massive-bedded compact light-gray and pinkish quartzitic Annelid trails and borings sandstones 125 {ScoHOius). Hj/olillies. 503 Olenellus canadensis ?. In the Lakes Louise and Agnes section, about 5 miles southeast of Mount Bosworth, the total thickness of the St. Piran sand- stone is ■. 2,705 Below the St. Piran the following section occurs: Lake Louise sliale [Walcott, 1908a, p. 5): 1. Compact gray siliceous shale 105 35d. Annelid trails— 35d. Cruziana — 35d. Micromitra (Ipliidclla) louise—35d. DETAILED STRATIGRAPHIC DISTRIBUTION. 131 Detailed stratigraphic distrihiition of Cambrian and Ordovician Brackiopoda — Continued. British Columbia: Mount Bosworth—Contiaued. Mount Bosworth section. [Walcott, 190Sf, pp. 204-217. Localities and species in the Mount Bosworth section. Other localities and species in British Columbia and Alberta shown in their approximate stratigraphic position. LOWER CAMBRIAN -continued. Bow River group— Continued. Fort Mountain sandstone: a 1. Thin and thick layers of gray, quartzitic, brownish weathering, Feet. compact sandstones (estimated) 600+ Total Lower Cambrian 3,800+ Total Cambrian 12, 353+ a In igOSCWalcott, 1908a, p. 5] these quartzitic sandstones were described as the "Fairview formation." As that name, however, is preoccupied in American nomenclature, and as the lower part of the formation has since been found exposed at several places on the east side of the Bow River Valley, it has been decided to apply the name Fort Mountain sandstone to the whole, from the typical exposures on Fort Mountain. The forma^ tion is here composed of 2,700 feet of sandstones similar to the 600 feet of sediments to which the name '*Fair\iew" was apphed, and a basal bed of massive conglomerate nearly 200 feet thick. At this locality the Fort Mountain formation is unconformably underlain by pre-Cambrian rocks. See Nevada, Barrel Spring section, where the California localities are shown in their approximate stratigraphic position. Cape Breton and New Brunswick. For the strata above the Etcheminian a generalized section only has been used. The Cape Breton localities have, however, been kept distinct from those in the vicinity of St. John. The Acadian is not represented in the brachiopod collections from Cape Breton. The Etcheminian is so well developed and so fossiliferous on Dugald Brook that Matthew's section is copied and the fossils from the brook are kept separate from those occurring elsewhere. Section. IJPPER CAMBRIAN. Bretonian [Matthew, 1903, pp. 49 and 240]: Di\dsion C3e2 {Asaphellus zone). Division C3c (Dktyonema zone). Localities and species occurring in Cape Breton arranged in their approximate stratigraphic position. 307a. LinguleUa cf. davisi — 307a. L ingulella ferTuginea — 307a. LinguleUa cf. lepis— 307a. Acrotreta hisecta—ZQlo.. (See 307a,p. 238,for additional associated forms.) Division C3b iPeltura zone). 3h, 3o-q, 8d, lOc-i, lOk-n, 13h, 16o, 307, 372. 372a-e. Obolus acadicus — 3h. Obolus refulgens— 307 , 372e. Obolus (Biuygeria) sa^cri— 3h,3q,10c,10d,]0e,10g, lOi, 10 i, 10m, lOn, 13h. LinguleUa concinna — 3h, 3o, 3p, 3q, 8d,10c,10e-h, lOi, 101, lOn, 13h, IGo, 307, 372, 372a-d. LingulcUafenuginea — 3h, 307. .■lrro//jc/esp.— lOf, lOh. AcTotreta cf. belli — 307. Acrotreta bisecta—3q, 10c, lOd-g, 101, lOn, 13h. Acrotreta convexa—lOe, lOi. Schizambon priscus—Sq, lOc-i, 10k, 101, 13h, 307, 372e. Orusia lenticularis — lOh. 3n1?, 13q, 307e?, 307h?, 307i. 307j1, 325?. Obolus ( Westonia) escasoni— 325. LinguleUa minor — 3n. LinguleUa (Lingulepis) exigua — 3n. Acrotreta convexa — 3n. Orusia lenticularis — 13q, 307e, 307h-j. (See 13q, 307i, 307j, and 325, pp. 183, 239, 240, and 259, for additional associated forms.) Localities and species occurring in the %icinity of St. John, New Brunswick, arranged in their approximate stratigraphic position. 308. Obolus refulgeTisSOS. LinguleUa ferruginea— SOS. Schizambon priscus — 308. Acrotreta bisecta~30S. Acrotreta belli ?— 308. 2zT, 301u. LinguleUa cf. lepis~30ln, Spharnphthahnus alatus — 301u. LinguleUa minor — 2x. LinguleUa minor? — 2x. LinguleUa (Lingulepis) starri—2x. Division C3a (ParaboUna zone). lOr, 325b. Obolus {BToggeria) salteri — lOr. Obolus (Palxobolus) bretonensis — lOr.. Obolus ( Westonia) escasoni^—lOi. LinguleUa Isevis (/rand is— 325b. LinguleUa lens—lOv. 301e, 301n, 301t, 308a, 308b, 308f. LinguleUa Ixii.s—'i'dln. LinguleUa Iseiis grandis — 301t. LinguleUa cf. lepis—301e. Orusia lenticularisSOSh, 308f. Orusia lenticularis atrypoides—SOSh. Orusia lenticularis lyncioides — 308b. Eoorthis atava—30Sa. Eoorthis io1iannensis—30S'b. (See 30Sb and 30Sf, p. 239, for additional associ- ated forms.) MroDLE CAMBRIAN. Johannian [Matthew, 1903, pp. 40 and 240]: Division C2c. 307b?, 307c. 325a. LinguleUa flumenis— 325a. LinguleUa radula—307h, 307c. LinguleUa rotundata— 325a. Acrotreta sp. undt.— 325a. 301x, 301y. LinguleUa radula—SOlx, 301y. 132 CMIBEIAN BRACHIOPODA. Detailed stratigraphic distribution of Camhriav mid Ordovician Brachiopoda — Continued. Cape Breton and New Brunswick— Continued. Section. Localities and species occurring in Cape Breton arranged in their approximate stratigraphic position. Localities and species occurring in the vicinity of St. John. New Brunswick, arranged in their approximate stratigraphic position. MIDDLE CAMBRIAN— continued. Joh an nia »^— Continued . Divisiou C2b ( Forchhammeri zone). 3i, lOoH, 10s!, lot!, llz??, 13i, 13r, 307g, 325c? Obolus ( Wcslonia) cscaso7u?—10o, llz. Linguldla cania — 3i, 10s. LinguhUa cnncimia — 3i. LiitQiililla f< rrugiiica — 3i. Lin'gulilla rolundnta—3i, 325c. Linguldla tumida—13i. 13r. Linguldla (Lingnlepis) exigua—3i, 10s, lOt, llz, 131, 13r, 307g. Acrothgra proavia — 3i. (See 10s and 307g, pp. 177 and 238, for additional associated forms.) 308c. Lingulella (Lingulepis) starri. — 308c. Division C2a. 307f. Linguldla {Lingulepis) exigua— 307!. Acadian [Matthew, 1903, pp. 39 and 240]:o Division Cld. 300, 30a 1. Linguldla ferruginea— 301 1. AcTothele matthewi — 301 1. Acrotkde prima costata— 301 1. Acrotreta hailcyi — 300. AcTOtrda misera — 301 1. (See both 300 and 3011, pp. 229 and 231, for additional associated forms.) Division Clc. 2e!, 21!, 2m!, 2s, 2t, 3b!, 301g, 301h, 301j, 301k, 301m, 301w (from lc2), 301z, 3081l (from Icl), 3081. Lingulella ferruginea— 2\, 2s, 301g, 301h, 301k, 301z. Acrotkde maltliewi—2\. 2s, 3b, 301g, 301h, 301], 301k, 301w, 301z, 308h. Acrothde matthewi lata— 301g. Acrotlide matthewi multicostata — 21, 2s, 2t. .4 crotrda gracia — 2s. Acrotreta misera — 2s, 2t. Acrotreta sagitlalis — 2s. Acrotreta sagitlalis magna— 2\, 2s. A crotrda sat/ittalis transversa — 301k. Discinopsis'guUdmi—3011., 301w, 308h. Billingsdla cnloradoensis — 2s. Billingsella sp.— 23. Frotorlhis billingsi—2e, 21, 3b, 301g, 301j, 301k, 308h, 3081. Frotorlhis latourensis—301g, 301w, 308h. Frotorlhis quacoensis—3\i, 301g, 301m, 301w. Eoorlhis haslingsensis—2\, 2s. (See 301g, 301h, 301k, 301m, 301w, 301z, 30Sh, and 3081, pp. 230-232 and 239, for additional associated forms.) Division Clb.5. 301b, 301d, 301f. Acrolhele prima costata — 301d, 301f. Acrotreta sagitlalis transversa — 301b. Division Clb4. 308d. Botsfordia pulchra. Division Clb3. 21, 2k, 2u!, 301a, 301c!, 308d, 308g (may belong with lb4). Lingulella ferruginea ? — 2i. Linguldla martinensis — 21. Botsfordia pulchra— 30Si. Botsfordia sp.— 21. Acrothde matthewi lala—301a. Acrothde matthewi prims— 301a. Acrolhele prima — 2i. Acrolhele prima coslala — 21, 2k. Acrotreta gemmula — .'iOla. Acrolrda sagitlalis magna — 21. Acrotreta sagiltalis transversa — 21, 2k, 301c, Acrotreta sp.— 301c. Trematobolus hemponvm — 2u, 308g. Trematobolus prislinus—2i, 2k. Frotorlhis hdcna~2u. Frotorlhis (Loperia) dugaldcnsis—2a. (See 2k and 301a, pp. 103 and 230, for addi- tional associated forms. ) a The Protolenus zone of Matthew in New Brunswick corresponds in large part with the Acadian. DETAILED STRATIGRAPHIC DISTRIBUTION. 133 Detailed siratigraphic distribution of Cambrian and Ordovician Brachiopoda — Continued. Cape Breton and New Brunswick— Continued. Section. Localities and species occurring in Cape Breton arranged in their approximate stratigrapliic position. Localities and species occurring in the vicinity of St. John, New Brunswick, arranged in their approximate stratigraphic position. MIDDLE CAMBRIAN — Continued. Acadian — Continued. Division Clb2. 2h, 301, 308d. Lingulctla martinensis — 2h. Acrollu/c mattliewi lata — 301. A crnlln /(' jirhna — 2h. Aci'tthih' prima costata—2h. Acrohtta buileyi — 301. Acrotreta gemmula — 301. Acrotrcta sagittalis transversa — 21i. Botsfordia pulchra—3asd. Trcmatobolus insignis — 301. Trcmatobolus pristinus — 2h, 301. (See 2h and 301, pp. 162 and 229, for additional associated forms.) Division Clbl. 2f, 2b, 2y?, 301i, 308e. LinguMla marlinensis—2t, 2g. Acrolhcle mallhetiii— SOU. Acrotkcle prima — 2f. Acrotrcta inflata—2S, 2g. Acrotreta sagittalis— 2g. Acrotreta sagittalis transversa — 2f, 2g. Botsfordia CKtoi— 308e. Botsfordia pulchra — 2y. (See 2g, p. 162, for additional associated forms.) Dugald Brook section. [Matthew, 1903, pp. 21-25.] Localities and species occurrmg in the Dugald Brook section. Localities and species occurring elsewhere in Cape Breton sho\vn in their approximate strati- graphic position. EtcJieminian: Division E3f. Feet. Siliceous gray shale 10 Dark-gray rather coarse shales 32 Dark-gray somewhat sili- ceous flaggy shales 40 13n, 344d. LingulcUa atava — 13n, 344d. Lingulella coUicia—Zad. Acrothele avia — 13n. Acrothele proles— Un, 344d. Acrotliyra proavia — 344d. (See 13n and 344d, pp. 182 and 289, for addi- tional associated forms.) 13m. Obolus (Palseobolus) bretonensis lens— 13m. Lingulella collicia — 13m. Acrothele avia— 13m. Acrothele avia puteis — 13m. Acrothele proles— 13m. Acrothyra proavia — 13m. (See 13m, p. 182, foradditional associated forms.) Division E3e. Dark-gray shale alternately hardfer and softer 18 13n'. Obolus (Patsobolus) bretonensis lens — 13n'. LingulcUa atava — 13n'. Lingulella collicia — 13n'. LingulcUa tumida — 13n'. Acrothele Qi7a— 13n'. Acrothgra proavia — 13n'. (See 13n', p. 182, lor additional associated spe- cies.) 344j. Acrothyra proama— 344j. Division E3d. Dark-gray and some pur- plish-gray shale 30 13n", 344b. Obolus (PaUeobolus) bretonensis— I3n" , 344b. Lingulella atava — 13n", 344b. Acrothele avia — 344b. Acrothgra proavia — 13n", 344b. (See 13n" and 344b, pp. 183 and 268, for addi- tional associated forms.) 344c. Obolus (Palseobolus) bretonensis — 344c. Acrothele avia puteis— 344c. Division E3c. Gray argillaceous sandstone. 25 344a. Lingulella collicia— iUa.. Lingulella sp. — 344a. Acrothele avia—iUa,. Acrotreta sp. — 344a. Acrothyra proavia— 3Ua. (See 344a, p. 268, for additional associated forms.) Division E3b. Fine gray shale 25 344. Obolus (Palseobolus) bretonensis — 344. LingulcUa atava — 344. Lingulella sp. — 344. Acrothele avia— 3U. Division E3a. Dark-gray feldspathic sand- stones, having seams of gray grit with felsite debris 60 Gray micaceous shale 4 234 131, 131', 3441. Obolus (Palseobolus) bretonensis — 131', 344i. Obolus (Palmobolus) bretonensis lens— 13 1, 344i. LingulcUa atava — 131'. Acrothele avia-lSl, 131', 3441. Acrothele proles— 131, 131'. Acrothyra proavia — 131, 3441. (See 131', p. 182, foradditional associated forms.) 134 CAJMBRIAN BRACHIOPODA. Detailed stratigraphic distribution of Cambrian and Ordovidan Brachiopoda — Continued. Cape Breton and New Brunswick— Continued. Pugald Brook section. [Matthew, 1903, pp, 21-25.] Localities and species occurring in the Dugald Brook section. Localities and species occurring elsewhere in Cape Breton slnwn in their approximate strati- graphic position. Etcheminian — Continued. Division E2c. Division E2b. Dark purplish-gray feld- Feet. spathic sandstones 57 Division E2a. Dark purplish-gray feld- spathic sandstone with beds of gray quartzite about the middle 37 Dark purplish-gray feld- spathic sandstone with some slate conglomerate. . 33 Gray fine-grained felsite conglomerate and grit 3 Division Ele. Gray shale with seams of greenish-gray sand and lavender-gray shale 3 Division Eld. Compact dark-gray sandy shale 21 Division Elc. Dark-gray shale 21 Division Elb. Gray quartzites with sand and clay seams at top . 6 Shales ? (concealed) 10 Purplish-gray finely crystal- line trap 18 Division Ela. Soft purplish-red shale 18 Dark purplish-gray trap and ash rock 10 Dark-p u r p 1 e amygdaloid and bright>red slates 15 13e, 3441. Obolas (Palxobolus) breionensis lens—lSe. Acrothyra proavia—l^e. Acrothyra sera — 13e. Acrothyra signata orta— 3441. (See 13e,p. 181, for additional associated forms.) lOp, lOq, 3440, 372f. Obolus {PaJscobolus) breionensis— lO'p. LingulcUa alava—lOp. Lingulclla coJUcia—lOp. LingulcUa triparilis — lOp. Lingulclla sp.— lOp. LingulcUa (Lingulepis) gregwa—lOp. Lingulclla (Lingulepis) longinervis—lOp, 344o, 372f. Lingulclla (Lingulepis) sp. — lOp. Acrothcle avia—lQp. Acrotrcta gemmula — lOp. Acrothyra proavia — lOp, lOq. Acrothyra sera— lOp. Acrothyra signata — lOp. Acrothyra signata orta — lOp. Frotorthis (Loperia) dugalaensis — lOp. (See lOp and lOq, pp. 176 and 177, for addi- tional associated forms.) 13d, 13d', 13d", 13f, 13g, 13p?, 13p'?. Obolus (PalsEobolus) breionensis— ISd' . Lingulclla (Lingulepis) longinervis—lZd, 13d", 13f, 13g, 13p, 13p'. LingulcUa atava—lSd' . Lingulclla collicia — 13d'. Acrothcle avia—lSd', 13d". AcTothele prima — 13d". Acroth7/ra sera— 13d', 13f, 13p, 13p'. Acrothyra signata — 13d'. AcrotliyTa signata orto— 13d". (See 13d and 13g, p. 181, for additional asso- ciated forms.) lOp', lOp". Obolus (Falseobolus) bretonensis—lOp" . Lingulclla (Lingulepis) gregwa — lOp', lOp". Lingulclla (Lingulepis) longinervis-lOp' , lOp". Acrothcle avia—lOp". Acrolreta gcmmula^-lOp" . Acrothyra sera — lOp', lOp".. (See lOp", p. 177, for additional associated forms. ) 344h. Obolus sp.— 344h. LingulcUa triparilis— Si4h. Lingulella cf. tomitZa— 344h. Lingulclla sp.— 344h. Lingulclla (Lingulepis) gregwa robusta—ZUh. (See 344h, p. 269, for additional associated forms.) 13t" (Elc and Eld), 344m. LingulcUa triparilis— ISt" . Lingulclla (Lingulepis) gregwa— 13t", 344m. Lingulclla (Lingulepis) gregiva robusta—344in. Acrothyra sera — ^13t", 344m. Acrothyra signata— IZt" . (See 13t" and 344m, pp. 183 and 270, for addi- tional associated forms.) 13t" (Elc and Eld), 344g. Lingulclla triparilis— 13t" , 344g. LingulcUa (Lingulepis) gregwa— IZt", 344g. Acrothyra 5cra— 13t", 344g. Acrothyra signata— ISt" , 344g. (See both 13t" and 344g, pp. 183 and 209, for additional associated forms.) 307d. Obolus selwyni—S07d. Lingulclla atava insulse—i07d . Lingulella triparilis— ZQId. Lingulella (Lingulepis) roberii — 307d. Acrotrcta sp. — 307d. BillingscJla rciroflexa—307d. (See 307d, p. 238, for additional associated forms.) 344e. 344n?. Obolus sp.— 344e. Lingulclla cf. collicia — 344e. Lingulella torrent7S—344e. Lingulclla (Lingulepis) gregwa— Mie, 344n. LingulcUa (Lingulepis) sp.— 344e. Acroihvra sera- 344e. (See"344e, p. 269, for additional associated forms.) 13t 13t' 344k. Ln'ignhUn Iriparilis-lSt, 13t", 344k. Li iig u 1(11(1 I ;i m ida — 13t. Lingulclla sp.— 344k. Lingulclla (Lingulepis) gregwa^-SUk. Acrothcle prima— IZt. Acrothyra signata — I3t, 344k. (See'both 13t and 344k, pp. 383 and 270, for additional associated forms.) 122 DETAILED STRATIGRAPHIC DISTRIBUTION. 135 Detailed stratigraphic distribution of Cambrian and Ordovician Brachiopoda — Continued. Cape Breton and New Brunswick— Continued. Dugald Brook section. [Matthew, 1903, pp. 21-25-] Localities and species occurring in tlie Dugald Brook seotion. Localities and species occurring elsewhere in Cape Breton shown in their approximate strati- graphic position. Coldbrook [Matthew, 1903, p. 15]. Feet. Felsites 185 Gray shales 25 13k, 344f. Micromitra (IpMdella) pannulaf — 13k. Obolus torrenii3—lZk, 344f. Lingulella cf. tripanlis — 344f. Lin^ulella (Lingulepis) pumila — 13k, 344f. Acrothyra sera — 13k, 344f. AcTothyra signata prima— 13k, S-Uf. (See 344f , p. 269, for additional associated forms. ) Felsitic conglomerate 100 LOWER CAMBRIAN, a a Fossils from the Lower Cambrian have been identified at but two localities (3a and 301 v), and these are on Hanford Brook, near St. John, New Brunswick, The Lower Cambrian is not represented in the brachiopod collections from Cape Breton. Colorado. Most of the Colorado forms occur in the siliceous beds of the Lower Ordovician. Three localities (360g-i) have been identified from the Upper Cambrian and two (3g and 360d) from the Middle Cambrian. For the numbers of all the localities see the index. See Sweden, Denmark, Finland, and Norway, where the horizons are more or less closely differentiated and corre- lated, with complete lists of localities and included species. England, Scotland, and Wales. Section. Localities and species. OEDOTiaAN. Bala ( Caradoc, Coniston) limestone. 304n, 366o. Lingulella davisir-ZOiD, 366o. Llandeilo shales. 316, 316a. Acrotreta nicholsoni — 316, 316a. LlanviTn. Arenig. UPPER CAMBRIAN. TTemadoc {Shineton, Bronsil, Lower Stockingford?) shales. 301, 304a, 30411, 3041, 304j!, 304k, 3041, 304p, 305, 30Sa, 30Sc, 305e-j, 318w, 366p, 366q. Obolus (Brdggeria) salteri — 304a. Lingulella (foMsi— 366p, 366q. Lingulella lepis—30Sa, 30.5c, SOoe-j, 366q. Lingulella nicholsoni— 30ia, 304i, 304k. Lingula sp. — 304a. AcTOthele intermedia— 30i} . , Acrotrem Mti—30i, SOia.. 305. * Acrotreta nicholsoni— 3fHh. 3041. Acrotreta cf. nicholsoni— 30i3. Acrotreta sabrinz—304h, 3041, 304j, 304p. ^cro(/ii/ra,»— 304a. Eoorthis carausii — 318w. (See 304a, p. 236, for additional associated forms.) Upper Lingula flags (White Leaved Oak shales, Dolgelly group, Upper Ffestiniog group). 304b, 304e, 304f, 305d, 318. 318a, 318b, 318s-v, 366s. Micromitra pusilla — 30tb. Obolus (Brbggeria) salteri— 30ic Linijutrlla ferruginca — 318u, 318v. Linguhlla lepist -305d. Linguhlta nicholsoni — 304b. Lirigulclla (.Lingulepis) pygmsea-SOU. Acrotreta sabrinse — 304b. Orusia lenticularis—3lii, 318a, 318b, 318s-v, 366s. Middle Lingula flags {Hollybush sandstone). 304g, 366a. Micromitra (Paterina) phillipsi — 304g. Lingulella davisi — 366a. Lingulella (Lingulepis) squamosa — 304g. Acrotreta sagittalis?—304^. (See 304g, p. 236, for additional associated forms.) 136 CAMBEIAN BRACHIOPODA. Detailed stratigraphic distribution of Cambrian and Ordovician Brachiopoda — Continued. England, Scotland, and Wales— Continued. Section. Localities and species. UPPEK CAMBRIAN— continued. Lower Lingula flags. 318c, 318g, 318m, 366!, 366d-n, 366r?. LinguUlla daii.ii-:il>im, 3UI>, 360d-n, 3601. Acrotreta sagiltalis—iiSC, 31Sg. MIDDLE CAMBRIAN. Menevian group. 316b!, 318d, 318e, 318f, 3181l, 318j, 318k, 3181, 318p, 318T. LingulcUaferruginea—il&e, 318h, 318j, SlSli, 31S1. Acrothele maculata—SlSd, 318e, 318t, 318h. Acrotreta sagittalis—3U\b, 31Sh. Orbiculoidea pileolus—Slid, 31Se, 318p, 318r. Billingsella hicksi—318d, Sl.Sh, 318p. Harlech grits. 318n, 318o, 318q, 366b. Lingulella ferruginea—ZlSn, 318o, 366b. Orbiculoidea pileolus? — 318q. Soha. MIDDLE? CAMBRIAN. Caerfai group. 318i,'366c. Lingulella primxva — 3181, 366c. LOITER CAMBRIAN. Malvern "quartzite" ( Comley, Serpulite grit, Fucoid beds). 304c, 304d, 304o, 316c, 316d. MicTomitra scotica — 316d. Micromitra {Patcrina) labradorica — 304o. Micromilra (Patcrina) phillipsiSOic, 304d. Lingulella zcus— 310c. Obolella jroomi— 304c, 304d. Olenellus lapworthif -316c, 316d. (See 304c, p. 236, for additional associated species.) Finland. See Sweden, Denmark, Finland, and Norway, where the horizons are more or less closely differentiated and correlated, with complete lists of localities and included species. Georgia. See Tennessee, Georgia, and Alabama, where the horizons are more or less closely differentiated and correlated, with complete lists of localities and included species. Germany. See Russia, p. 143 and footnote, for stratigraphic position of four localities from East Prussia. Idaho. See Utah, Blacksmith Fork section, where the Idaho localities are shown in theh approximate stratigraphic position. Iowa. See WisconBin, Michigan, Minnesota, and Iowa for general discussion of stratigraphy. LabiadoT. See Quebec, Ontario, and Labrador for general discussion of stratigraphy. Maryland. See Virginia and Maryland for general discussion of stratigraphy. Hlcliigan. See Wisconsin, Michigan, Minnesota, and Iowa for general discussion of stratigraphy. Minnesota. See Wisconsin, Michigan, Minnesota, and Iowa for general discussion of stratigraphy. DETAILED STRATIGRAPHIC DISTEIBUTION. 137 Detailed stratigraphic distribution of Cambrian and Ordovidan Brachiopoda — Continued. Missouri. Section. Localities and species. UPPER CAMBRIAN. Elvins formation. lid, 111, 369, 369b, 369c. 369d, 369e. Obelus ismene — 369. Obolus matinalisf — lid. Linguldla acutangulaf — 11 1. LingukUa texana—SG9. LinnarssoncUu girti/i—369. BilUngsella coloradoensU —lid, 11 1, 369d, 369e. BilUngseUa major?— 369c. Eoorthis indianola—S&9, 369b. Eoorthis Tcmnicha texanaf— lid, 111. MIDDLE CAMBRIAN. Elvins formation (basal part or "Edgewise beds").a lie, Ilk, 369a. Obolus matinalis? — lie. Lingulella acutangula — Ilk. Linguldla similU—llQ. Linguldla sp. — lie. Linnarssondla giTtyi— lie. Ilk. AcTofreta microscopica missouriensis — lie, Ilk. BilUngsello coloraaoensis— lie. Eoorthis wickitaensis—SG9a.. Bonneterre limestone. llj, 11m, 369f, 369g, 369h. MicTomitra sp. — llin. Micromitra {Paterina) cf. st IssivgenMs— llm. Obolus lamborni-^ll}, 11m, 309f, 369b. Obolus sinoe—l\}. Linguldla acutangula — llj. Linguldla desiderata— Z&^g. Lingulella cf. ora— 11m. Dicellomus nanus— llj, 11m. Dicellomus politus—llm. Lamotte sandstone. Montana and Wyoming. The sedimentation in Montana and northwestern Wyoming exhibits so many peculiarities that correlation ia difficult, even between sections only a few miles apart. The Wolsey shale occupies a position immediately above a sandstone in the Little Belt Mountains and is Middle Cambrian in age. It can thus be closely correlated with the similarly situated Flathead shales of Peale, which are also Middle Cambrian. On Dearborn RiA^er, however, a shale which occupies the same stratigraphic position [see Walcott, 1908f, pp. 202-203] carries a typical Lower Cambrian fauna in its lower part and Middle Cambrian in its upper layers. The sandstone underlying the Dearborn River shale horizon is Lower Cambrian in age, and that underlying Peale's Flathead shales has been found to contain a fairly well developed Middle Cambrian fauna. The Gallatin formation of Peale has a very wide geographic distribution, and collections have been made at many localities. The various horizons can not be differentiated, but the faunas show clearly that his Gallatin is in part Upper Cambrian and in part Middle Cambrian. A limestone in the Phillipsburg quadrangle that is believed to be the equivalent of the Yogo limestone of the Little Belt Mountains has been found to contain both Middle and Upper Cambrian fossils. The localities (see index for numbers) give all the known data as to the stratigraphy of the different collections. Nevada: Barrel Spring. Barrel Spring section. [Walcott, 1908f, pp. 188-189.] Localities and species in the Barrel Spring section. Other Lower & Cambrian localities and species in Nevada and California shown in their approximate strati- graphic i>osition. A section of Lower Cambrian strata studied by Mr. F. B. Weeks near Barrel Spring. 16 miles south of the town of Silver Peak, Nevada, is much like that east of Waucoba Springs, and has about the same fauna at various horizons in it. LOWER CAMBRIAN. 1. Massive blue-mottled limestone, with 50 feet of sandy limestone in the middle of the series 737 Arch^ocyathus and allied forms occur throughout. a It has been agreed, but too late for any other correction than the insertion of this footnote, that the " Edgewise beds" should be placed in the Upper Cambrian. b Three scattering localities have been identified as Middle Cambrian, and eight locaUties were collected from the Emigrant formation (upper Cambrian) of Turner in the Silver Peak district. See index for locality numbers. 138 CAIMBEIAN BRACHIOPODA. Detailed stratigraphic distribution of Cambrian and Ordovician Brachiopoda — Continued. Nevada: Barrel Spring— Continued. Other Lower Cambrian localities ajd Barrel Spring section. Localities and species in the Barrel species in Nevada and California (Walcott, 190Sf, pp. 1S8-1S9.1 Spring section. shown in their approximate strati- graphic position. LOTiViER CAMBRUJf — Continued. 2. Sandv shales succeeded by coarse thin fine sandstone Feet. Im, Ip. 53, 53a, 174c, 176, 176a, 178a, 312, 312a. with biiff limpstonp At top 20tl In limestone: MickiL'itzia occidcTis — 53, 174c. Micromitra (Paterina) prospecien- O6o/U5?— 174c. 5W— Im, Ip. ObolcUa vermilionensis—53, 170. Nisusia {JamcscUa) amii — Im, Ip. Obohlla sp.— 53a, 174c, 170. 312a. SceneUa sp.— Im, Ip. Tnmatobolus excelsis—SS, i70a, 312, Agraulos^—lva, Ip. 312a. OkncUiis fremonti—lp. Tnmatobolus sp. — 17Sa. Olcnellus gilberti—lni, Ip Billingsdla highUmdensis—lTSSi. Wanmria gracUe—oZ, 17Sa. Okndlus frcmonti—lTSa.. Holmia rou'fi— 312. 3. Green calcareous shale, arenaceous at top 390 ll.lv. ArchseocyatkiLS ?— Iv. 7, 141, 14o, 14p, 175, 184, 313i. Obolus ?— 175. Micromitra (Paterina) labradorica Linguhlla (Lingulepis) rowef— 14p. var.— lY. Kutorqina pcmgata — 7, 175, 184, 313L KutoTQinn cingulata—\x. Obolella vermUioncnsis — 14p. Kutorgina pcrmaia—lv. Obohlla sp.— 140. Siphonoii eta? dubia—l\. Yorkia wanneri? — 7. Acioihele spurriF — 1 1. AcTotreta ctaytoni — 1 1. Acrotreta claytoni—l7o, 1S4. Swantonia sp.— 175. Swantonia weeksi — Iv. Billingscllabivia—l-i\. 14p. Swantoniaf sp.— It. Wanneria gracile — 14p. Stcnotheca cf. elongata — Iv. Olenellm fremoTiti—lil, Up. Stenotheca cf. rugosa — 1y. Salter ella— 1 1. ' Ptychoparia sp. — 11, Iv. Wanncria gracile — Iv. , Olendlus argcntits — Iv. Olemllus giiberti—l\. 49 5. Mainly green shales, some quartzjtlc shale, bands of 580 6. Green calcareous shale, with bands of limestone at top 564 11, lb. Olenellus claytoni—li, Ik. Olenellus fremonti^-? Olenellus gilberti—li. 7. Andesite mass 7.50 8. Massive blue-mottled limestone 81 9. Green calcareous shale 2.38 10. Mostly thin-bedded blue and gray shaly quartzite. . . 904 11. Sihceous limestones at base, then blue coral lim.e- stone 1, 349 12. Massive quartzite, shaly in places 222 13t Siliceous buff limestone 180 Total 6, 250 Base unknown. If. Nevadia weeksi — If Holmia ro2C€i—li. DETAILED STRATIGKAPHIC DISTRIBUTION. 139 Detailed stratigraphic distribution of Cambrian and Ordovidan Brachiopoda — Continued. ITevada: Eureka District. Eureka district section. Localities and species in the Eureka Other localities and species in eastern [Walcott, 1884b, p. 284; and 1908f, p. 184.] district section. Nevada shown in their approximate stratigraphic position.a ORDOVICIAN. Pogonip limestone.- Feet 221? Interstratified limestone, argillites, and arenaceous Acrotreta sp. undt. — 221. beds at the base, passing into purer fine-grained lime- stone of a bluish-gray color, distinctly bedded and highly fossiliferous 2,700 63. 201a, 202?, 203, 204, 209. 214a, 2Ub, 313d, 313k. Obolm anceps—G3. Obolus rotundatus — 313d. Obolus m sera— 202. Obolus sp. undt. c— 214a. Obolu^ (Wcstonia) iphis— 201a. Lingulella manticula — 2i4b. LinguhUa maniicula — 202. Limiarssonella minuta — 313k. Lingulella pogonipensis— 201a.. LinguleUa sp.— 202. Elkania ambigua—GS, 202. Acrothele sp.— 201a. AcTotTeta idahocnsis — 201a, 202. A crotreta idahocnsis alta—C>i. Schizambon tyvicalis — 201a. SrMzambonr -m. KooTthis haniburgcnm—20la, 202. Syntrophia nundina—e,Z, 201a, 203, 204, 209. (See 201a, 202. and 203, p. 228, for additional associated forms.) PASSAGE BEDS. Pogonip limestone (lower portion). 201, 203a, 205. 206a, 211? Obolus m3era—205, 211. Obolus (IVestonia) sp. undt. b— 205. Lingulella manticula — ^211. LinguleUa pogoni pens is— 201, 2Q3a, 205, 211. AcrotTetaf? canc€llata—20b. AcTOtTela curvata— 205. AcTotreta idahoensis alta — 201. 206a. Eoorthis hamburgensis, 201, 205, 211. (See 203a and 211, pp. 228 and 229, for additional associated forms.) UPPER CAMBRIAN. Dunderberg shale: 56?, 61, 62, 62a?, 64. 65, 66, 313h?, 313j. 8e, 8f. 8n. 8o, 8p, 313, 313f?. Yellow argillaceous shale, layers of chert nodules through- MicromitTa sculptilis — 61, Ci2. Micromitra sculptilis endlichiSo. out the bed, but more abundant near the top 350 Obolus anceps — 61. Micromitra sp.—So. Obolas discoideus—(\2, 64, C6. 313j. Micromitra (Paterina) crenistria — 313. Obolus mxra — 61, 313j. Obolus discoideus— Si. Obolus nundi-na-Ol. Obolus rotundatus — 8o, 8p. Obolus (Westonia) iphis — 64. Lingulella arguta — 313f. Lingulella desiderata — 56, 61. Lingulella desiderata — 8n, 313. Lingulella manticula — 61, 62. Lingulella mc— 313. Lingulella punctata— Gl, 62. Lingulella manticula— 8e, 8f, 313f. Linnarssonella minuta—313h. Lingulella punctata — 8f, So. Acrotreta idahoensis— 313. Acrotreta atlenuata — 61. Acrotreta idahoensis— 61. Acrotreta microsco pica—So. Acrotreta pyxidicula—313L Acrotreta idahoensis alta—Gl, 65. Acrotreta spinosa— 61, 62, 62a, 65. Eoorthis sp.—So. Acrotreta sp.— 61. Eoorthisf-S'i. (See 56, -(il, f)2, 62a, 64, and 66, pp. 206, 211, and 212, for additional associ- ated species.) Hamburg limestone: Dark-gray granular lim.estone, surface weathering rough and ragged, with only slight traces of bedding. 1, 200 MIDDLE CAMBRIAN. Secret Canyon shale: 58, 60. 7i, Sm?, lOw, 313b, 313c?, 313e. Yellow and gray arfjillaceous shales passing into shaly Micromitra sculptilis — 58. Micromitra sculptilis— lOw. limestone: near the fop interstratified layers of shale Micromilra (Paterina) crenistria?—5S. Micromitra (Paterina) crenistria— 313b. and tliinly bedded limestones 1,600 Obolus discoideus — 58. Obolus mcconnelli — Sm, lOw. Obolus msera — 58. Obolus mcconnelli dccipiem — 8m. Obolus mcconnelli~o8. Obolus rotundatus— 7i. Obolus nundina—oS. Obolus {Acritis?) rugatus — 58. Lingulella acutangula — 313c. Lingulella arguta— 313e. Lingulella clarkei~oS, 60. LinguleUa desiderata— 313h, 313c. Lingulella desiderata— 5S 60 LinguleUa manticula — 7i. Lingulella punctata— 5i* Lingulella punctata— ~i. Lingulella sp.— 60. Linnarssonella girtyi — 313e. Acrothele dickofoma — 58. Acrotreta idahoensis alta-Ti, 313b. Acrotreta idahoensis alta— 5? Acrotreta microscopica — 58. Acrotreta p'/xidicula~GO. (See both 58 and 60, pp. 209 and 211, for additional associated species.) a Some of the localities placed in this column could as well have been correlated with the Utah (House Range) section, entered under both. Locality 41 has been 140 CMIBRIAN BRACHIOPODA. Detailed stratigraphic distribution of Cambrian and Ordovician Brachiopoda — Continued. liTevada: Eureka District— Continued. Eureka district section. [Walcott, lSS4b, p. 284; and 190Sf, p. 184.] Localities and species in the Eureka district section. Other localities and species in eastern Nevada shown in their approximate stratigraphic position. MEDDLE CAMBRIA.N— continued. Eldorado limestone: Gray compact limestone, lighter in color than the Ham- burg limestone, traversed with thin seams of calcite; Feet. 64, 55, 55bT, 57, 57bl, 59?. LinguleUa arguta— 54, 59. Lingulella desiderata — 57, 57b. LinguleUa punctata— b4, 57. Acrotreta attenuata—59. Acrotreta definita — 55, 57. Billingsella whitfieldi— 55, 55b. Orusia €urekensis—55h. Orusia lenticular is— 55h. (See 55, 55b, 57, and 59, pp. 205, 207, and 210, for additional associated species.) 14m, 313a. Lingulella arguta — 14ni. Lingulella arguta?— S132L. LOWER CAMBRIAN. Shales occupying the position of the Pioche formation at Pioche, Nevada, and in the House Range (see p. 158), Utah, and correlated with it. 52. Micromitra (Paterina) prospcctensis— 52. Callavia nevadensis— 52. Olenellus fremonti — 52. Peachella iddingsi— 52. (Etc., seep. 201.) 41.a Micromitra (IphideUa) pannula — 41. Acrotreta claytoni — 41. Acrotreta primseva — 41. Prospect Mountain quartzUe: Bedded brownish- white quartzite, weathering dark bro\s'Ti; ferruginous near the base; intercalated thin layers of arenaceous shales; beds whiter near the summit 1, 500 oAlso in the Utah (House Range) section. New Brunswick. See Cape Breton and New Brunswick, wliere the horizons are closely differentiated and correlated, with com- plete lists of localities and included species. Newfoundland: Uanuels Biook, Conception Bay. Manuels Broolc section. [Walcott, 1891b, pp. 260-261.] Localities and species in the Manuels Brook section. Other localities and species in Newfoundland shown in their appro-ximate stratigraphic posi- tion. LOWEB OKDOVICliN. (Not exposed.) 114b, 314c, 314d, 314g. Obolus cyane-ilid. Obolus ? murrayi — 314g. Obolus {Lingulobolus) affinis—\Uh. Obolus {Lingulobolus) spissus — 114b. Obolus OVcstonia) rogersi—lUb. Lingulella bella—Uil>. Lingulella eoZc— 314d. Acrotreta gemma — 314d. Syntrophia calcifera — 314c. (See 314c and 314d, pp. 246 and 247, tor addi- tional associated forms.) UPPER CAMBRIAN. 3, 6u, 6v. LinguleUa ferruginea — 6u. AcTOthele matthewi—3. Acrotreta sagittalis transversa— 3. Orusia lenticularis — 3, 6v. 114, 114a. LinguleUa bella—lU, 114a. Lingulella bellula—lU, 114a. (8) Alternating bands of dark shale and Feci. dark, compact sandstone 400 6s, 6y, 314a!, 3141?. Lingulella bilUngsiana — 314a. Lingulella ferruginea ?— 6s. LinguleUa randomensis — 6y. Orusia lenticularis— Z\4i.. MIDDLE CAMBRIAN. (7) Dark arprillaceous shales, \vith thin layers of limestone and sandstone at various horizons 29.5 1 (zone A) and 2 (zone B). Obolus fragilis — 1, 2. Lingulella ferruginea— 1, 2. Acrothele matthewi — 1, 2. Acrotreta misera—1, 2. (See both 1 and 2, p. 161, for additional asso- ciated forms.) 2a, 6i (corresponding to zone A). Lingulella ferruginea — 2a. Acrotreta sagittalis— 61. Agnostus — 6i. Microdiscus — 61. (6) Green argillaceous shale, with thin layers of hard dark ferruginous sandstone interbedded at several horizons 270 la, 61, en, 6r, 314h?. Obolus fragilis — 1 a. LinguleUa ferruginea— la, 6n, 6r. Acrothele matthewi— Isl, 61, 8n. Acrothele prima costata — 6n. Acrotreta misera — 6n, 314h. Acrotretaf—Cil. Eoorthis papias—u\. 6h, 6w, 314. Acrotreta misera — 6h, 314. Acrotreta sagittalis— Sw. (See 314, p. 246, for additional associated forms.) DETAILED STEATIGRAPHIC DISTEIBUTION. 141 Detailed stratigraphic distribution of Cambrian and Ordovician Brachiopoda — Continued. Newfoundland; Manuels Brook, Conception Bay — Continued. Manuels Brook section. [Walcott, 1891b, pp. 260-261.) Localities and species in the Manuels Brook section. Other localities and species in Newfoundland shown in their appro-ximate stratigraphic posi- tion. MIDDLE CAMBRIAN— continued. (5) Calcareous sandstone, with pinldsh Feet. limestone in irregular masses 2 (4) Reddish-colored argillaceous shale. 4 (3) Greenish argillaceous shale 40 6g? Micromitra (Iphidella) ornatella — 6g. Micnmitra (Iphidella) pannula maladensis—6g. LingulcUa fenuginea — 6g. AcTolhele matthewi — 6g. AcTotreta miscTa — 6g. Acrotreta sagUtaUs—6g. LOWEK CAMBEIAN. 5r, 41. MicTomitra (Paterina) labradorica — 5r. Obolella atlanlica— 41. Callavia hroggeri—bv, 41. (See 41, p. 199, for extensive list of associated species.) So, 314b. Kutorgina granulata — 314b. Obolella atlanlica— ho. Olenellus? — 5o. 6n. Obolella atlantica — 5n. Callavia broggeri — on. (2) Irregular beds of calcareous sand- stone, siliceous limestone, and greenish argillaceous shale, cover- ing the upper surface of ( 1 ) 0-25 51. 6p, 5t, 41a, 314e, 314f. Micromitra {Paterina) bella — 314e. Micromitra {Patcrina) labradorica — 51, 5t, 41a, 314e, 314f. Obolella atlantica— St^, 5t, 41a. Obolella chromalica — 314f. Mesonacis vermoniana — 314f. Callavia broggeri — 5p, 5t, 41a. Olenellus f— 51. (1) Coarse conglomerate, in massive layers, resting on gneiss 35 New York. Five or six of the New York localities are scattering; the remainder may be separated into two groups, Upper Cambrian (Potsdam) and Lower Cambrian. In each of these divisions little stratigraphic differentiation is possible, but the localities (see index for numbers) give all known stratigraphic data. Norway. See Sweden, Denmark, Finland, and Norway, where the horizons are differentiated and correlated, with com- plete lists of the localities and included species. Nova Scotia. See Cape Breton and New Brunswick, where the horizons are closely differentiated and correlated, with com- plete lists of localities and included species. Oklahoma: Arbuckle Mountaius. For the Arbuckle limestone the section 7 miles north of Springer, on the south side of the Arbuckle Mountains, is used, and for the Reagan sandstone a section measm-ed by E. O. Ulrich in sec. 2, T. 4 N., R. 13 W., on the north side of the Arbuckle Mountains, 15 miles northwest of Fort Sill. Springer section, south side of Arbuckle Mountain. Localities and species in the Springer section. Other localities and species in Oklahoma in their approxi- mate stratigraphic position. ORDOVICTAN. Arbuckle Hmestone:a Feet. 1. Compact dolomitic limestone with occasional calciferous fossils, nearly 4, 500 2. Rather thin-bedded, mostly compact, gray or blue limestone, with granocrvstalUne layers in lower half containing fossils, mainly trilobites 250 3. Crystalline limestone weathering dark and breaking down into rough bowldery jointed masses, in which the sedimentation is much obscured. Upper member granocrystalline and gray; middle mem- ber with white and pink marble; lower member granocrystalline and dark gray to white 305 a The section of the Arbuckle limestone was measured on the south side of the Arbuckle Mountaius, 7 miles north of Springer. 142 CAjMBRIAN brachiopoda. Detailed stratigraphic distribution of Cambrian and Ordovician Brachiopoda — Continued. Oklahoma: Arbuckle Mountains— Continued. Springer section, south side of Arbuckle Mountains. Localities and species in the Springer section. Other localities and species in Oklahoma in their approxi- mate stratigraphic position. UPPER CAMBRIAN. A rbuckle limestone: Feet. 4. Heavy bedded compact gray limestone 4 12m. Obolus tetonensis ninus— 12m. L'lngulella similis — 12m. Eoorthis remnicha icxana — 12m. 9z, 12 j. EooTthis wichitaensis — 9z, 12j. 6. Heavy bedded compact gray limestone 4 7. TMn-bedded shaly and clayey limestone, often yellow, wltli some limestone conglomerate; no fossils 0-40 Section measured in sec. 2, T. 4 N., R. 13 W., north side of Arbuckle Mountains, by E. 0. Ulrich. Localities and species oc- curring in the section quoted. Localities and species occurring in the Springer section (12k and 12n) and elsewhere in Okla- homa shown in their approxi- mate stratigraphic position. UPPER CAMBRIAN. Reagan savdstone:a Feet. 1. Highly calcareous sandstone, with numerous pure crystalline lime- stone lenses and layers containing fossils 175 (125 feet above the base.) 911. Obolus tetonensis ninus— 9u. Lingulella similis— 9u. Eoorthis indianola—9u. Eoorthis wichitaensis — 9u. Syntrophia primordialis — 9u. 9ql, 9s, 9w, 12n, 12p?. Obolus tetonensis ninus — 9q, 9s, 12n, 12p. Lingulella similis— 9s, 12n, 12p. Lingulella ora — 9q. Lingulella (Lingulepis) acumi- nata—9q, 9s, 12n,12-p. Linnarssonella girtyi — 9q, 12p. Acrotreta curvata~-V2p. Acrotreta microscopica— 12n, 12p. Acrotreta ulricki — 12p. Eoorthis indianola—dw, 12n, 12p. Eoorthis remnicha — 12n, 12p. Eoorthis remnicha texana—l2n. Eoorthis wichitaensis— 9q, 9s. 12n. 12p. Eoorthis wichitaensis Iseviv^cvr- lus—12n, 12p. Syntrophia primordialis — 12n. (100 feet above the base.) 9t. Obolus matinalis—9t. Obolus tetonensis ni reus— 9t . Lingulella similis— Qt. Acrotretamicroscopica—9t. Eoorthis indianola—9t. 12k. Obolus tetonensis ninus— 12^. Lingulella similis— 12k. Acrotreta microscopica— 12^. Eoorthis indianola— 12k. Eoorthis remnicha — 12k. Eoorthis wichitaensis— 12k. Eoorthis wichitaensis Ixviuscur lus—12k. (90 feet above the base.) 9p. Obolus tetonensis ninus— V-p. LiiKjulclla ora — 9p. /. / n na rssonella girtyi — 9p . 9x. Dicellomus politus. (45 feet above the base.) 12s. No brachiopods. Trilobites not studied. 9v1. Lingulella (Lingulepis) acumi- nata—9v. Linnarssonella girtyi — 9v. 2. Originally massive calcareous sandstone, now leached into laminar, (Beds between 2 and 3 are fossiliferous.) 9r. Obolus tetonensis ninus— 9t. LingvleUa similis— 9t. Linnarssonella girtyi— 9r. Acrotreta microscopica—9v. 3. Whitish crystalline limestone, almost made up of fragments of large cystids. With the limestone small lenses and layers of glauconitic sandstone are interpolated 24 Base formed of a glauconitic grit 20 feet thick, containing several layers of por- phyry pebbles and resting on porphyry. o The section ofthe Reagan sandstone was measured on the north side of Arbuckle Mountains, in sec. 2, T. 4 N., R. 13 W. The Reagan is much more fossiUferous and has a greater development in the section northwest of Fort Sill, in Comanche County, than it has on the south side of the Arbuckle Mountains, in Carter County. DETAILED STRATIGRAPHIC DISTRIBUTION. 143 Detailed stratigraphic distribution of Cambrian and Ordovician Brachiopoda — Continued. Ontario. See Quebec, Ontario, and Labrador for general discussion of stratigraphy. Pennsylvania. All but two of the Pennsylvania localities (see index for numbers) are from approximately the same horizon in the Lower Cambrian. One locality (346b) is from the Upper Cambrian and one (48d) from the Middle Cambrian. Quebec, Ontario, and Labrador. Three general horizons fi"om Quebec and Ontario are represented in the collections: An Ordovician (Chazy?), an Upper Cambrian equivalent to the Potsdam of New York, and a Lower Cambrian in limestone pebbles in a conglomer- ate. The Lower Cambrian forms may be compared with those occurring in localities 392a, 392c, and 3921, all at the Straits of Belleisle, Labrador. See index for numbers of all localities in Quebec, Ontario, and Labrador. Section. Localities and species. ORDOVICLA.N. Jewe limestone (D). 337e. Si pkonotreta unguiculata—337e. Itfer limestone (C3). Kucker limestone (," BrandscUefer") (C2). 337d. Siphonolreta unguiculata—SSld. Eckinosphseritcs limestone (CI). 336, aaeg?, 336v, 336w, 336x, 386i-l. Volborlhia rccurva — 336g. A crofrda subconica — 336. Siphonotrela unguiculala—3i6g, 336t, 336w, 336x, 386i, 3S6j. Siphonotreta verrucosa— 336w , 386i, 386k, 3861. Upper " Linsenschicht." • PASSAGE BEDS. Orthoceratile ( Vaginoceras) limestone (" Va^inatenkalk") (B3): B3r=^sapftMS ric/iwaWi zone. B3/?=.45apftws ranicepi- zone. Q'ia= Asaphus expansus zone. 336d, 336e, 336f, 336z, 337, 337a, 337b, 337c, 337f, 337k, 337h, 337i, 337k, 3371, 337m, 396n, 396p. VolbOTthia recurva — 337j. Obolus {Mickwitzella) siluricus — 336f. Obolus (Acritis) anliquissimus—SSHd, 336e, 337h, 396n, 396p. Siphonotrela unguiculata—336e, 336z, 337, 337a, 337b, 337c, 337k, 3371. Siphonotrela verrucosa— 33. undt.— 310e. Acrothele sp. undt.— 310t, 310g. D!scinella—3M, 390a, 390d, 330h. Eophyton sandstone (Mickwitzia conglomerate, Sparagmile sandstone). By, 390j, 390k. Mickwitzia monilif era— 390], 390k. Mickwitzia prrtioss- 390j . Lingulella nathorsti — Sy. (See 8y and 390j, pp. 173 and 280, tor additional associated forms.) DETAILED STEATIGRAPHIC DISTEIBUTION. Detailed stratigraphie distribution of Cambrian and Ordovidan Brachiopoda — Continued. Tennessee, Geoigla, and Alabama. 147 Section. Localities and species in Tennessee in their approximate stratigrapMc position. Localities and species in Georgia and Alabama in their approximate stratigraphie position. UPPER CAMBRIAN. Knox dolomite. 7d!, 12q, 105, 107o, 107u, 1221, 122a?, 128!, and 128a?. 06o(«5 lamhornx—'&, 122. Obolus toilUsi — 122. Lingulella desiderata— 10~o, 107u, 122, 122a. LiuiiultUa ino — 7d. Lin'quUUa sp.— 128a. Lingidaia9~l2S. Lingulella (Lingulepis) acuminata — 105. Acntreta lutorgai~107o, 107u. Syntrophia campbelli — 12q. 93, 93a, 93n, 93o, 93x, 94o, 96, 361!, 362?. Micromitra alabamaemis — 94o. Micromitra {Iphidella) pannula— 96. Obolus rotundatus—90. Obolus willisi — 93, 93n, 93x. Lingulella desiderata— 93, 93a, 93o, 94o, 96, 361, 362. Lingulella leos — 96. Acrotreta kutorgai — 361. Acrotreta sp.— 940. MroDLE CAMBRIAN. Nolichucky shale. & s < 03 '^ tf> "is. ■■§8 o 1 c o O 2z, 11a??, 124, 124a, 374c, 374d1. Micromitra atabamaensis — 12-1. Obolus lamborni — 124a. Obolus lambonu minimus — 121. Obolus sinoe — Ua. Lingulella tarpa — 11a. Lingulella {Lingulepis) acuminata — 124a, 374d. Dicellomus appalachia—2z, 11a, 124a, 374c. 16, 56o, 56q, 56u, 89, 90, 90a, 90b, 90c, 90x, 91, 92x, 94, 94a, 94x, 94xx, 95a, 98b, 96x1, 137, 138!, 139, 139a, 140, 140a, 140c, 141a, 144c!, 1451, 146, 362a?, Micromitra atabamaensis— 90x, 94, 94a, 95. Micromitra {Paterina) major — 90. Obolus lamborni — 140a. Obolus sinoe — 92x. Obolus willisi— 9i, 94a, 96b, 140a, 146, 362a. Maryville limestone. || as si 11 123. Micromitra atabamaensis — 123. Ptijchoparia—V2i. Obolus {Westonia) ella— 90, 141a. Lingulella 6«((si— 90b, 90c. Lingulella desiderata — 90b, 94xx, 139. Lingulella hat/esi—90x, 94a. Lingulella nanno — 16, 91. Lingulella quadrilnteralis — 5Gq. 91. 140a. Lingulella similis— 90, 92x, 138, 140c. l'!5. Lingulella sp.— 140c. Lingulella {Linaulepis) acuminata— %9. A crothele bdlula—90x, 94x. Acrotreta concentrica—90x. Acrotreta kutorgai— 90, 90b, 90x, 137, 139a. 140. Acrotreta sp.— 56o, 56u, 94xx. Dicellomus appalachia — 16. S9, 00a, 90b, 91, 144c. Wimanella anomala—90. Agnostus — 90b. Ptyclioparia sp.— 56q, 90b, 90x. A nomocare — 90x. Olenoides curticei— 90. 90x. Laoiira cambria—90x. Rogersmlle shale. 18??, 101, 101a, 101b, 102, 102c?, 121, 121a?. Micromitra atabamaensis — 121. 121a. Micromitra (Iphidella) pannula — 101. Obolus lamborni— imh, 102, 121. Obolus lamborni minimus — 101, 101a. Obolus willisi- 101b, 121. Lingulella desiderata — 101a. Dicellomus appalachia — 102. Acrotreta kutorgaif — IS. Acrotreta rwdis— 101a. 102c, 121. Bitlingselta appalachia — 121. Wimanella tiartanensis — 121. Rutledge limestone. Rome formation. 91, 9a?, 10a, 10b, 11, 121, 13, 13b, 14a, 103, 103a, 103b, 104?, 106. 106a!. 107, 107a, 107b, 1171, 117c, 118,1191,374?, 374al,374bl, 374e?. Micromitra atabamaensis — 14a. Obolus lamborni— 103. Obolus lamborni minimus — 103a, 118. Obolus pandemia— lOa.. Obolus witlisi-imsL, 107a. 107b, 374e. Obolus (Wcslonia) etla—Ua. Linquteltaauga — 10a, 10b. Lin'ijutclta desiderata— 9. 9a, 103b, 107a, 117. Lingulella ino—n, 13, 13b. Lingulella simitis—Sa, 10a, 14a, 106, 374. Lingulella tarpa — 11. Lin gulella f—107h. Dicellomus appalactlia— 103a., 104, 107, 107b, 117c, 11!), 374a, 374b. lAnnarssonella tennesseensis — 12, 13, 107b. Wimanella harlanensis — 107. Wimanella sajfordi — 14a. 13c, 14, 138a, 142, 164fl. Micromitra (Iphidflla) pannula— 14. Oholus? SD.— Itl4f. Lingulella /no— 13c. Lingulella similis — 13Sa. Acrolrrta kutorgaif— 142. BiUingsella appalachia — 14. Dori/pyge?~i4. LOWER CAMBRUN. Rome formation, basal part, locally known in Alabama as"Montevallo shale." 17b, 56c. Micromitra (Paterina) major— 17h, 56c. Micromitra {Paterina) williardi — 17b, 56c Obolas smithi—\7h, 56e. Wimanella shelbyensis-llh, 5Gc. Psedeumias transitans—h%c. Wanner ia halli — 56c. AqrauloRf-h^Q. Byolithes—5Ge. Beauer limestone. Weisner quartzite. 59m. Obolella cf. ailantica— 59m. Obolella of. crassa — 59m. A rchxocyathus—dQm. Stenotheca cf. rugosn.—bQjn.. Olenellus thompsoni— 59m. 148 CMIBRIAN BRACHIOPODA. Detailed stratigraphic distribution of Cambrian and Ordovician Brachiopoda — Continued. Texas. The Texas localities are from the Upper Cambrian, at about the stratigraphic horizon of the Reagan sandstone of the Oklahoma section. Utah: Blacksmith Fork, Cache County. Blacksmith Fork section. [Walcott, 190Sf, pp. 190-200.1 Localities and species in the Blacksmith Fork section. Other localities and species in Utah and Idaho shown in their approximate strati- graphic position. The Blacksmith Fork section is located in Blacksmith Fork Canyon, on the east side of Cache Vallej', in the Wasatch Mountains, between Ute and Logan Peaks, about 10 miles east of Hvrum, in northern Utah. This section is 230 miles northeast of the House Range section (Utah) and is north of the greater ellect of the pre-Cambrian Cinta Mountain uplift and island. The character of the sediments derived from the Uinta area is shown by the con- tinuation of the arenaceous deposits up to the middle of Middle Cambrian time, whereas in the House Range section the arenaceous deposits cease before the Mid- dle Cambrian fauna appears. It is not until after the Belt Mountain and Kintla (of the 49th parallel) uplifts to the north are passed that the order of sedimenta- tion as shown in the Mount Bosworth section is again of the type of the House Range section. ORD0^^CIAN. Feet. 1. Dark, bluish-black, and gray limestone. In the basal bed imme- diately above the Cambrian a fine fauna occurs. The lime- stone is of the same character as that of the Upper Cambrian for 190 feet below, and, except for the change in the fauna, there is no break in the section. One of the characters common to the Cambrian and the superjacent Ordovician is the presence in most layers of flattened concretionary nodules and stringers from a minute size up to 6 or S cm. or more in diameter; the large ones rarely exceed 3 to 10 mm. in thickness. 1852. EoortMs desmopleura — 185z. SyntTophia 7iundina—lS5z. Orthoceras—lSoz. EndoceTos—lSoz. Fragmentsoftrilobites— ISoz. 105xT. Obolus (Westonia) elongatus—105x. UPPER CAMBRLAN. St. Charles limestone [Walcott, IQOSa, p. 6]: 1. Dark, bluish-gray, and gray limestone in layers varying from 1 to 20 inches in thickness. Many of the layers are almost made up of flattened concretions varying from a" minute size to 6 or 8 cm ". 190 54b, 54c, 54d. 25 feet below the top: Lingulella manticula—o-ih, Eoortkis desmopleura — 54b. Syntrophia nundina—dih. DicenocepJialus—5-^h. 105 to 125 feet below the top: Schizambon typicalis—bAc. Eoortkis desmopleura— S\Q. Eoorthis newberryi—S-ic. Syntrophia nundina—5^c. Solenopleura— 54c. Men ocephaJus — 54c. IllEenurus—b\c. 20 to 30 feet above base: Lingulella {Lingulepis) acuminata— 54d. Eoorthis desmopleura— Bid. Eoorthis newberr yi— 5-id. Agnostus — 54d. Solenopleura~o4d. Menocephalu-s—a-id. Asaphus? — 54d. 54r, 32ga. Eoorthis desmopleura— b^. Syntrophia nundina—^29a,. 2a. Massive-bedded dark lead-gray arenaceous cliff-forming limestone, becommg thiimer bedded in the lower 50 feet. 195 26. Massive-bedded gray arenaceous limestone with a few irregu- lar cherty layers 'which extend down S5 feet, just below which the dark arenaceous limestone for a thickness of about 15 feet is almost made up of round concretions 2 to 4 mm. In diameter 100 2c. Gray sihceous and arenaceous limestone in layers one-half inch to fi inches thick, occurring in massive bands. Light- gray chert fills large and smaU anneUd borings, and it also occurs as flattened strmgers in the Ime of the bedding and 54j. Obolus (Westonia) iphis—oi}. Lingulella desiderata— Sij. 2d. Massive-bedded arenaceous limestone, formmg broken cliffs. A few cherty nodules occur near the top, and the lower 50 feet has many irregular oval cherty nodules and stringers of 777 DETAILED STRATIGRAPHIC DISTRIBUTION. 149 Detailed stratigraphic distribution of Cambrian and Ordovician Brachiopoda — Continued. Utah: Blacksmith Fork, Cache County— Continued. Blacksmith Fork section. Localities and species in the Blacksmith Fork Other localities and species in Utah and Idaho sho^vn in [Walcott, 1908f, pp. 190-200.) section. their approximate strati- graphic position. UPPER CAMBRIAN— continued. St. Cltarles Zimesfone- Continued. Feet. 3. Bedded bluish-gray fossiliferous limestone 94 31m, 31n, 54e, 55ta. 4y, 5a, 5c, 30q, 30s, 54t, 54w, Upper part; 542:. Acrotreta sp. — 31n. Obolus rotundatus — 30q. A nomocare — 31n. Obolus tetonensis ninusSiw. Near base: Obolus wortheni — 5a, 5c, 54t, 54w, Obolus sp. undt.— 31m, 54.x. 65h. Obolus {Westonia) ella — 4v. Lingulella manticula— 31m. Lingulella desiderata— ba,'bit. Billimjsella coloradoensis — Lingulella isse — 30s. 31m, 55h. Lingulella mantieula-SOq. Agnostus—'ilm, 55h. Acrotreta idahoensis — 5c, 54t. P(i/cftoporia— 31m, 55h. Acrotreta idahoensis sulcata — 54t. Anomocare—bSh. Billingsella coloradoensis — 4y, 5a^ A mLxture of the faunas at 54t, 54x. the base and at the top: Agnostus— biw, 54x. Obolus discoideiis — 54e. Ptychoparia — 54t, 54w, 54x. Obolus? sp. undt.— o4e. Liostracus — 54w, 54x. Lirufulella manticula — 54e. .4 nomocare — 54t, 54w, 54x, Sillingsella coloradoensis— Damesella sp.— 54w, 54x. 64e. Ptychaspis — 54w, 54x. Huenella lesleyi—oie. Hyolithes—bie. Ci/rtolites—bie. Agnostus — 54e. PtycUoparia — o4e. A nomocare — 54e. 4. Bedded light-gray sandstone, followed below by dirty-brown sand- S4f, 54g. 34q, 64u, 56g. stone and toward the base shaly and thtn-bedded sandstone. 166 In upper 20 feet: Obolus discoideus—Mi. Obolus discoideus — 56g. Obolus mcconnelli pelias — 34q. Total Upper Cambrian (St. Charles limestone) . . . 1, 227 Obolus {Fordinia) bellulus Obolus wortheni — 54u. — 51f. Acrotreta idahoensis alta — Acrotreta idahoensis — 54u, 56g. Acrotreta idahoensis alta — 34q. 54f. Billingsella coloradoensis— bia, Billingsclla coloradoensis — 50g. 54f. Platyceras—b6g. Near the base: Agnostus — 54u, 56g. Lingulclla (Lingulepis) Ptychoparia— bin, 56g. acuminata— big. ^nomocarf— 54u. Ptychaspis— bia. MIDDLE CAMBRIAN. Nounan limestone [Walcott, 1908a, p. 6]: la. Light-gray arenaceous limestone 12 A few traces of fossils occur 56f?. lb. Lead-colored arenaceous limestone 40 in the lower 28 feet and Obolus matinalis—bdt. Ic. Light-gray arenaceous limestone 85 large annelid borings occur Lingulella manticula — 56f. Id. Dark lead-graT arenaceous limestone 87 in many of the arenaceous Orthotheca—bSt. le. Shaly and thin-bedded arenaceous limestone with intercalated limestones. In the dark Agraulos — 56f. reddish-brown sandy layers 15 rock the irregular borings are flHed with lighter-col- Ptychoparia— 56f. If. Light-gray arenaceous limestone 18 A nomocare— bQt. 1(7. Dark lead-gray arenaceous limestone 198 ored rock, and in the light- A nomocarella — 56f. Ih. Light-gray arenaceous limestone 494 gray rock by darker rock. Solenopleura — 56f. li. Dark lead-gray arenaceous limestone, with numerous irregular annelid borings filled with light-gray arenaceous limestone. . 53 Ij. Massive-bedded arenaceous cherty limestone 8 Ifc. Bluish-gray cherty more or less arenaceous limestone in thick bands that break up into thin layers on weathering 28 1,041 • Bloomington formation: 311, S4h. 33j, 329. la. Thin-bedded bluish gray compact limestone with interUedded Protospongia (spicules) — 54h. Obolus (Westonia) ella— 329. thick layers of gray limestone 22 Obolus mcconneid pelias — Obolus (Westonia) wasatchensis — 54h. 33j, 329. Ptychoparia quadrans — 329. Obolus (Westonia) wasatch- ensis — 54h. Olenoides wasatchensis — 329. Lingulella desiderata— Zl 1, 64h. Hyolithes—bih. Agnostus — 31 1, 54h. Ptychoparia—biii. 16. Greenish argillaceous shale 12 Ic. Gray coarse-grained limestone 13 55m. HyolUhes — 55m. Ptychoparia — 55m. 150 CAMBRIAN BRACHIOPODA. Detailed stratigraphic distribution of Cambrian and Ordovician Brachiopoda — Continued. Utah: Blacksmith Fork, Cache County— Continued. Blacksmitli Fork section. [Walcott, 1908f, pp. 190-200.) Localities and species in the Blacksmith Fork section. Other localities and species in Utah and Idaho showm in their approximate strati- graphic position. MIDDLE CAMBRIAN— continued. Bloomington formation — Continued. Feet. Id. Greenish argillaceous and sandy shale 147 SSk. Hyolithes (fragments) — 55k. Agnostus—oSk. Btychoparia — 55k. 541. Micromitra sculptilis — 54i. Hyolithes (abundant) — 541. Ptychopaiia—iyii. AgTaulos—bii. 220 2a. Bluish-gray limestones, with small concretions and small nodules of calcite scattered through the layers, which range from an inch to 6 inches or more in thickness 380 31j. Fragments of fossils— 31j. 26. Massive-bedded gray limestone that forms a low cliff and breaks down readily on gentle slopes 132 55s. 5r3r-}sameasinl.. 2c. Bluish-gray limestone, with small concretions and small nodules of calcite scattered through the layers; a limestone similar to2o 290 311. Hyolithes— ■ili. Agraulos — 31i. 2d. Greenish argillaceous shale 39 64k. Obolus (Westonia) wasatch- ensis — 54k. Agraulos— b4k. Ptychoparia—54'£. ehl, 32x, 33t, S4q, 55di. Micromitra (Iphidella) pannula? -5iq. Obolus sp. undt. — 54q. Obolus (Westonia) ella—Sk. Obolus (Westonia) wasaicheTisis — 32x,33t, 54q,55d. Acrothele subsidua — 54q. Nisusia alberta— 5iq. Nisusia alberta ? — 54q. 2e. Bluish-gray thin-bedded limestone 182 2/. Arenaceous steel-gray limestone 22 2g. Bluish-gray limestone, with small concretions and small nodules "of calcite scattered irregularly through the layers . . . 55 31h, 55n. Mierom itra sculptilis — 31h, 55n. Ptychoparia—Uh, 55n. Dorypygc—31h, 55n. 54v. Obolus wortheni—54v. Plychoparia, 2 species— 64v. Total of Bloomington formation 1, 320 Blacksmith limestone [Walcott. 1908a, p. 7]: la. Dark lead-gray arenaceous limestone 195 16. Arenaceous steel-gray clifl-forming limestone, in the lower por- tion passing gradually into a dove-gray compact limestone that weathers to a light-gray color. "The layers vary In thickness from 4 Inches to 2.5 feet 375 Total of Blacksmith limestone . . . 570 31g. Fragments of a small trilo- bite (Plychoparia f )— 31g. Annelid borings — 31g. Vte limestone [Walcott, 1908a, p. 7]: lo. Bluish-gray compact thin-bedded limestone, with large irregu- lar anne"lid borings in the upper part filled with steel-gray arenaceous limestone similar to the beds above. Below, the limestone is purer and more uniformly gray and in layers that tend to form low clifls on the steeper slopes 290 64m. In upper part: Micromitra (Paterirm) la- bradoTica utahensis — 54m. Billingselltt sp. undt.— S4m. Hyolithes— Mm. A graulos — 54m. Plychoparia subcoronata— 54m. Dorypyge ? quadriceps — 54m. DETAILED STEATIGRAPHIG DISTRIBUTION. 151 Detailed stratigraphic distribution of Cambrian and Ordovician Brachiopoda — Continued. Utah: Blacksmith Fork, Cache County— Continued. Blacksmith Pork section. Localities and species in the Blacksmith Fork Other localities and species in Utah and Idaho shown in [Walcott, 1908f, pp. 190-200.] their approximate strati- graphic position. MIDDLE CAMBRIAN — Continued. Ute limestone — Continued. 1ft Grfav arenaceous limestone in tliin layers, with a few bands of Feet. 31c, S4o, SSo. 30u, 32e, 32n, 34in. layers 4 to 10 inches thick, often oolitic, and with interfor- In the upper 5 feet: Micromitra (Paterina) labradorica mational conglomerate and flattened concretions 135 Scenella — 55o. PtycUoparia subcoronata— 650. Dorypyge ? quadriceps— 55o. In layers 70 to 80 feet below the top: ilicromitra (Paterina) la- bradorica utahensis — 54o. Obolus mcconnelli— 31c. AcTotreta cf. opMrensis — 31c. AcTolrcta sp. undt. — 31c. Billingsella coloradoensis — 540. Otusia utahensis — 31c. utahensis— 30u, 34m. Obolus (Westonia) clla ?— 32n. Acrotreta cf. ophirensis — 30u. SyntTophia cambria — 32e, 34m. • Eoorthis zeno — 31c, 54o. SyntTophia Cambria— 3lc, 540. Byolithes — 540. Scenella — 54o. Zacanthoidcs — 31c. Ptychoparia subcoronata — 31c, 640. Dorypygc f quadriceps— 31c, 640. Ic. Gray limestone, with numerous concretions one-fourth to one- half inch in diameter. A few thin layers of iuterforma- 68 483 31e, Sia. 30p, 31z, 32y, 55t, 339c?. •2a Gray, fine-grained, calcareous and argillaceous shaly beds 38 Micromitra (Paterina) labra- dorica utahensis^54a. Obolus (Weslonia) ella—31e. 54a. AcTothele tmnerif-Sia. Isoxys cf. argcntea-bifi. Ptychoparia— 31e, 54a. Micromitra (Paterina) labrador^ ica utahensis— 301). Obolus mcconnelli — 30p. Obolus (Westonia) ella—30p, 32y, 55t, 329c. Acrothele subsiduaf—iit. Acrotreta ophirensis — 31z, 55t. 26. Bluish-gray to blue-black, fine-grained, thin-bedded limestone. 57 Obolus?. Ptychoparia. 2c. Greenish argillaceous and calcareous shale, weathering bufl 51 ?(l 36 S4n. ?.e. 24 arii — 54n. Micromitra (Paterina) su- perba — 54n. Hyolithes-Sin. Ptychoparia a — 54n. Ptychoparia b — 54n. Dorypyge (fragment)— 54n. S4p. 31y!. 2;. Greenish argillaceous and sandy shale 18 Micromitra (Paterina) su- perba—Mp. Obolus mcconnelli — 54p. Obolus mcconnelli — Sly. Lingulella isse—31j. Ptychoparia sp. undt.— 64p. S4y. 59g. ?n Bluish-gray thin-bedded limestone . 22 Micromitra (Paterina) su- Lingulella sp. — 59g. Acrothele subsidua—59g. 246 perba—biy. Huolithes—oiy. Acrotretad. idahocnsis—59g. Ptychoparia (small heads)— Microdiscus—b9g. 64y. Ptychoparia, 3 species— 59g. Neolenus — 59g. Zacanthoidcs idahoensis — 59g. Menace phalus—Sig. 152 CMIBRIAN BRACHIOPODA. Detailed stratigraphic distribution of Cambrian and Ordorician Brachiopoda — Continued. Utah: Blacksmith Folk, Cache County— Continued. Blacksmith Fork section. [Walcott, 190Sf, pp. 190-200.] Localities and species in the Blacksmith Fork section. Other localities and species in Utah and Idaho shown in their approximate strati- graphic position. MIDDLE CAMBRIAN— continued. Ute limestone—Contmued. 2ft. Spence shale member [Walcott, 19DSa, p. S]. (Greenish argillaceous Feet. anrl sandy sh9,lp. 1 .^0 31d. 541. Micromitra (Iphidella) pan- Obolus (Wcstonia) ella—Sld, 541. LingulcUa desiderata— 54.1 Hyolith€s—b4l. Orthotheca major— 541. Leperditia—bi]. Ptychoparia—3ld, 541. Bathyuriscus productus—5A\. 32c. 32d, 32p, 55c, 55e, 163. Eocystitis ? longidactylus—hhe. Micromitra (Patcrina) labrador- ica utahcnsis—32d. Micromitra (IphidcUa) pannula — 55c, 55e. Obolus {W(sionia) d?a— 32d. 55e. Lingvldla d(sidcrat/i~ooe. Acrothdc subsidua^32p, 55c, 55e, 163. Acrotreta definita—b5c, 163. Acrotrcta idahoensis sulcata— 55c 363. Acrotreta cf. ophirensis—32c. Nisu^ia {Jamesella) nautes—55c 163. Nistbsia (Jamesella) spencei— 55c 163. Agnostus—5bc, 55e, 163. MicTodiscu s— 55c . Ptychoparia piochensis—55e. Ptychoparia— 55c, 163. Zacanthoides idahoensis— 55c, 55e 163. Zacanthoides sp.— 55c. Neolenus a — 55e. Neolenus b—55e. Olenoides— 55c. Bathyuriscus howelU—5oe. Bathyuriscus productus— 556. Ogygopsis—ooe. Oryctoccphalus reynoldsi—55c. Oryctocara gctkiei—55c. HyoUthes— 55c. • Lari^ston limestone [Walcott, 190Sa, p. 8]: la. Massive-bedded bluish-gray limestone passing downward into gray arenaceous limestone, with many round concretions J to f inch in diameter 64 0) Obolus (Westonia) ella. Zacanthoides sp. Bathyuriscus productus. Neolenus?. 5b, 54s, 59f, 322, 322a. Micromitra haydcni— 54s. Micromitra (Iphidella) pannula— 5-is, o9f. Micromitra {Iphidclla) pannula maladensis—o4c . Micromitra (Iphidclla) pannula ophircnsis— 54s. LinguMla desiderata— 54s, 59f. LingulcUa helena^54s. LingulcUa isse—54s. Acrothdc artemis— 54s. Acrothcle subsidua— 54s. Acrothde subsiduu var.— 54s. Acrotreta idahoensis sulcata— 54s, Acrotreta pyxidicula— 54s, 59f,322. Acrotreta? — 54s. Acrothyra minor— 54s. Billingsella coloradoensis— 54s, Hyolith€s—54s. Orthotheca— 54s. Stenotheca—o4s, 59f. PlatyceTas—54s. Agnostu^— 54s. Microdiscus— 54s, 322a. Solenopleura'-54s, 59f. Ptychoparia, 2 species— 54s, 59f 322a. Oryctoccphalus — 54s. Dorypyge, 2 species— 54s. Neolenus, 2 species— 54s, 59f. A saphiscus— 54s. Ogygopsis ?—o4s. Agraulos — 59f. A nomocar e—59(. Zacanthoides— 59f. 16. Massive-bedded bluish-gray limestone that breaks up into lay- ers 2 to S inches thick on weathering and ^vith many round concretions U lOS 55p. Ptychoparia—bbp. Bathyuriscus pTodv£tv^—obp. 2. Massive-bedded dark arenaceous limestone, passing at about 150 feet down into a calcareous sandstone and then a graj' sandstone , 390 Brigham guartzite [Walcott, 190Sa, p. S]: la. Quartzitic sandstone, gray-greenish, gray-brownish, dirty grav, all weathering reddish dirty brown, in layers 3 inches to 3 feet in thickness 28 DETAILED STKATIGRAPHIG DISTRIBUTION. 153 Detailed stratigraphic distribution of Cambrian and Ordovician Brachiopoda — Continued. 'Utsih: Blacksmith Fork, Cache County — Continued. Blacksmith Fork section. [Walcott, 1908f, pp. 190-200.] Localities and species in Other localities aiid species in the Blacksmith Fork H.*^ ^^^ ^^^° sHovm in section ! t°^"' approximate strati- graphic position. inDDLE CiMBEiAN— continued. Brigham g«Ta 2 26 4 15 2 2 Acrotreta 3 12 2 Bicia Biilingsella 5 1 9 2 3 1 1 Botsfordia Clarkella 1 Dearbornia 1 Delgadella 1 3 6 1 2 1 Discinopsis 1 2 23 1 1 9 Eoorthis 9 4 2 Finkelnburgia .... 3 1 1 1 2 48 1 10 3 5 2 2 8 1 3 4 8 1 30 1 1 1 2 1 2 4 14 3 1 1 Huenella . . . 8 1 Kevserlingia 4 35 3 36 2 7 1 6 6 5 7 7 4 1 1 3 Liunarssonella 2 2 Mickwitzia Micromitra 9 5 13 5 3 10 1 3 X riphidella) 1 (Paterina) 2 2 4 Nisusia 5 10 6 3 3 3 2 3 Obolella 2 1 1 (Glvptias) 35 2 1 3 2 18 5 1 5 1 3 ( Broggeria) 1 1 ( Fordinia) 1 2 (Lingulobolus) (Mickwitzella) (Palseobolus) 2 2 I'SnhTTiirltifll 8 6 2 1 2 1 1 2 Orusia 4 2- 1 2 1 1 5 2 1 1 (Loperia) 1 1 1 2 2 1 1 2 1 Schizopholis i 2 Siphonotreta 1 2 1 6 4 1 Syntrophia 10 1 1 2 3 Trematobolus 1 1 Wiinanella 4 1 1 1 " Yorkia 3 1 1 44 310 33 199 60 240 21 44 14 50 14 28 IS Species 33 LOCALITIES. The following list gives all known data concerning all localities from which fossils described in this paper have been obtained. After most of them reference is given to the pages on which their stratigraphic position is shown (pp. 124-159) . Those that are without references are more or less isolated places for which stratigraphic data are lacking and which are without near neighbors to which they may be profitably compared. An asterisk (*) placed before the name of a species indicates that the place from which it is cited is its type locality. In localities 1-227 and C1-C75 the Brachiopoda are not accompanied by author names, but for purposes of identifica- tion the author names follow all other listed species. In locaUties 300 to 396z all the Hsted species are accompanied by a reference to either the place of citation or the museum in which the specimens are located. In all lists the Brachiopoda are placed first. Numbers 1-227 were assigned to the different localities represented in the United States National Museum at the time of their accession and indicate distinct faunules. Numbers LOCALITIES. 161 C1-C75 (pp. 286-291) were assigned to the faunules collected by the expedition to China of the Carnegie Institution of Washington. Numbers 300-396z (pp. 229-286) have been arbitrarily- assigned to localities mentioned m the literature or unnumbered localities in the United States National Museum collections, and the included species may not occur together as do those of the former localities. For each of the species listed in localities 300-.396zit is simply true that the description of the locality under wliich it is placed gives all available information as to its stratigraphic and geographic position and the authority for so listing it. Localities 1-227, U. S. National Museum. 1 (about 50 feet above la). (For stratigraphic position and association, see p. 140.) Middle Cambrian: Shales of zone A of No. 7 of the Manuels Brook section [Walcott, 1891b, p. 261], Manuels Brook, a small stream which flows into Conception Bay from the east, near Topsail Head, Newfoundland (C. D. Walcott, 1888). *Obolus fragilis. Lingulella ferruginea. Lingulella ferruginea?. Acrothele matthewi. Acrotreta misera. Conocoryphe matthewi (Hartt). Paradoxides hicksi Salter. Paradoxides sp. Anopolenus venustus Billings. Eriunvs venulosa Salter. Walcott [1891b, p. 261] cites the following additional species: Hyolithes sp. a. Agnostus 3 sp. Microdiscus punctatus Salter. Conocoryphe elegans (Hartt). Agraulos socialis Billings. Liostracns tener (Hartt). la (^6n and 6 1, about 50 feet below 1). (For stratigraphic position and association, see p. 140.) Middle Cambrian: Shales near the top of No. 6 of the Manuels Brook section [Walcott, 1891b, p. 261], Manuels Brook, Concep- tion Bay, Newfoundland (C. D. Walcott, 1888). Obolus fragilis. Liostracus tener (Hartt). Lingulella ferruginea. Conocoryphe elegans (Hartt). Acrothele matthewi. Paradoxides davidis Salter. Agraulos socialis (Billings). Paradoxides sp. 11 (same horizon as Iv). (For stratigraphic position and association, see p. 138.) Lower Cambrian: Shales of No. 3 of the Silver Peak group, Barrel Spring section [Walcott, 1908f, p. 189 «], 2.5 miles (4 km.) south of Barrel Spring and 0.5 mile (0.8 km.) east of road, in the extreme southeastern corner of the Silver Peak quadrangle (U. S. G. S,), Esmeralda County, Nev. (F. B. Weeks, 1899). Acrothele spurri?. I Ptychoparia sp. Acrotreta claytoni. | Olenellus gilberti Meek. Im (=lp). (For stratigraphic position and association, see p. 138.) Lower Cambrian: Limestones of No. 2 of the Silver Peak group, Barrel Spring section [Walcott, 1908f, p. 189], about 2.5 miles (4 km.) south of Barrel Spring and 0.5 mile (0.8 km.) east of the road, in the extreme southeastern comer of the Silver Peak quad- rangle (U. S. G. S.), Esmeralda County, Nev. (F. B. Weeks, 1899). Micromitra (Paterina) prospectensis. I Olenellus gilberti Meek. Nisusia (Jamesella) argenta. | Ip (=lm, which see). (For stratigraphic position and association, see p. 138.) (F. B. Weeks, 1899.) Micromitra (Paterina) prospectensis. I Olenellus fremonti Walcott. * Nisusia (Jamesella) argenta. | Olenellus gilberti Meek. Iv (same horizon as 11). (For stratigraphic position and association, see p. 138.) Lower Cambrian: Shales of No. 3 of the Silver Peak group. Barrel Spring section [Walcott, 1908f, p. 189«], 3 miles (4.8 km.) north of Valcalda Spring and 4 miles (6.4 km.) west-northwest of the Drinkwater mine. Silver Peak quadrangle (U. S. G. S,), Esmeralda County, Nev. (F. B. Weeks, 1899). Aichasocyath us . *Micromitra (Paterina) labradorica var. Kutorgina cingulata. *Kutorgina perugata. *Siphonotreta? dubia. *Swantonia weeksi. Swantonia sp. Stenotheca cf. elongata Walcott. Stenotheca cf. rugosa (Hall). Ptychoparia sp. Wanneria gracile Walcott. Olenellus argentus Walcott. 2. (For stratigraphic position and association, see p. 140.) Middle Cambrian: Shales of zone B of No. 7 of the Manuels Brook section [Walcott, 1891b, p. 261], Manuels Brook, Conception Bay, Newfoundland (C. D. Walcott, 1888). Obolus fragilis. Lingulella ferruginea. Acrothele matthewi. a The species mentioned by Walcott [1908f, p. 189] occur at slightly different localities (11 and Iv), none of the species being common to both localities. 62667°— VOL 51, pt 1—12 11 162 CAJVIBRIAN BRACHIOPODA. Walcott [1891b, p. 261] cites the following: Lmnarssonia misera=Acrotreta misera. Orthis sp. Stenotheca sp. Agnostus punctuosus Angelin. Agnostus 5 sp. Microdiscus punctatus Salter. Paradoxides davidis Salter. Paradoxides hicksi Salter. Paradoxides sp. 2a (same horizon as 1). (For stratigraphic position and association, see p. 140.) Middle Cambrian: Above and to the north of the limestone, in the shales of the Paradoxides zone, Topsail Head, Conception Bay, Newfoundland (C. D. Walcott, 1888). Lingulella ferruginea. 2b. Lower Cambrian: Limestone just north of Beman Park, in the northeastern part of the city of Troy, Troy quadrangle (U. S. G. S.), Rensselaer County, N. Y. (H. E. Dickhaut, Anopolenus venustus Billings. Conocoryphe elegans (Hartt). Ctenocephalus matthewi (Hartt). Erinnys venulosa Salter. Ptychoparia robbi Hartt. Ptychoparia variolaris Salter. Holocephalina inflata Hicks. Agraulos socialis Billings. Micromitra (Paterina) labradorica. Bicia gemma. *Bicia whiteavesi. Obolella crassa. Botsfordia cselata. Billingsella salemensis. 2d. Lower Cambrian: Arenaceous limestone in the knobs just east of Beman Park and southwest of Brunswick, near Troy, Troy quadrangle (U. S. G. S.), Rensselaer County, N. Y. (H. E. Dickhaut, 1899). Obolella crassa. 2e (see 3b). (For stratigraphic position and association, see p. 132.) Middle Cambrian; Shale 25 feet (7.6 m.) above the basal quartzite, Seeley Street, St. John, St. John County, New Brunswick (S. W. Loper, 1899). Protorthis billingsi. 2{ (3 feet below 2g; see 308e). (For stratigraphic position and association, see p. 133.) Middle Cambrian: Sand- stones of Division Ibl of Matthew's [1895a, p. 108] Protolenus zone, Hanford Brook, St. John County, New Brunswick (C. D. Walcott and S. W. Loper, 1899). *Lingulella martinensis. Acrothele prima. *Acrotreta inflata. Acrotreta sagittalis transversa. 2g (3 feet above 2f and underlying 2h; see 308e). (For stratigraphic position and association, see p. 133.) Middle Cambrian: Sandstones of Division Ibl of Matthew's [1895a, p. 108] Protolenus zone, Hanford Brook, St. John County, New Brunswick (C. D. Walcott and S. W. Loper, 1899). Lingulella martinensis. I Acrotreta sagittalis. *Acrotreta inflata. ! Acrotreta sagittalis transversa. Matthew cites the following additional species from Division Ibl: Acrothele matthewi? (Hartt). I *Hipponicharion eos Matthew. *Acrothele matthewi prima Matthew = Acrothele prima. | Beyrichona tinea planata (Matthew). 2h (overljang 2g; see 301). (For stratigrapliic position and association, see p. 133.) Middle Cambrian: Sandstones of Division lb2 of Matthew's [1895a, p. 108] Protolenus zone, Hanford Brook, St. John County, New Brunswick (C. D. Walcott and S. W. Loper, 1899). Lingulella martinensis. Trematobolus pristinus. Acrothele prima. *Acrothele prima costata. Acrotreta sagittalis transversa. Matthew cites the following additional species from Division lb2 Beyrichona tinea Matthew *Beyrichona tinea planata (Matthew). Beyrichona rotundata Matthew. Beyrichona ovata Matthew. Indiana secunda Matthew. 21 (underlying 2k). (For stratigraphic position and association, see p. 132.) Middle Cambrian: Sandstones of Division IbS of Matthew's [1895a, p. 108] Protolenus zone, Hanford Brook, St. John County, New Bruns- wick (C. D. Walcott and S. W. Loper, 1899). Lingulella ferruginea?. Acrothele prima. Lingulella martinensis. " Acrothele prima costata. Botsfordia sp. Acrotreta sagittalis magna. Trematobolus pristinus. Acrotreta sagittaUs transversa. LOCALITIES. 163 Matthew cites the following additional species from Division lb3: Bradoria benepuncta (Matthew). Bradoria minor (Matthew) . *Bradoria cambrica (Matthew). Bradoria oculata (Matthew). Indiana lippa (Matthew) . Indiana secunda pyriformis (Matthew). Walcottella fusiformis (Matthew). Beyrichona tinea Matthew. Beyrichona tinea planata (Matthew). *Beyrichona tinea triangularis (Matthew). Beyrichona papilio (Matthew). *Beyrichona rotundata Matthew. *Hipponicharion minus Matthew. *Hipponicharion cavatum Matthew. 2k (just above 2i). (For stratigraphic position and association, see p. 132.) Middle Cambrian: Sandstones of Division lb3 of Matthew's [1895a, p. 108] Protolenus zone, Hanford Brook, St. John County, New Bruns- wick (C. D. Walcott and S. W. Loper, 1899). Trematobolus pristinus. Acrothele prima costata. Acrotreta sagittalis transversa. Matthew cites the following additional species from this locality: Indiana secunda pyriformis (Matthew). Beyrichona tinea Matthew. 21 (underlying 2m). (For stratigraphic position and association, see p. 132.) Middle Cambrian: Limestone at the base of the Paradoxides zone [Matthew, 1895a, p. 108], Hanford Brook, St. John County, New Brunswick (S. W. Loper, 1899). Lingulella ferruginea. Acrothele matthewi. Acrothele matthewi multicostata. Acrotreta sagittalis magna. Protorthis billingsi. *Eoorthis hastingsensis. Matthew cites the following additional species from the base of the Paradoxides zone at this locality: Beyrichona tinea Matthew. 2m (overlying 2 1). (For stratigraphic position and association, see p. 132.) Middle Cambrian: Shales near the base of the Paradoxides zone [Matthew, 1895a, p. 108], Hanford Brook, St. John County, New Brunswick (S. W. Loper, 1899). Lingulella ferruginea. I Protorthis billingsi. Acrothele matthewi. | Eoorthis hastingsensis. 2n. Lower Cambrian: Limestone bowlders in conglomerate along the shore of the St. Lawrence, near Trois Pistoles, Temiscouata County, Quebec, Canada (C. D. Walcott, 1899). *Micromitra (Paterina) bella. *Micromitra (Paterina) logani. 2o (see 2p and 2r). Lower Cambrian: Limestone bowlders in conglomerate on shore at east entrance to harbor at Bic, Rimouski County, Quebec, Canada (C. D. Walcott, 1899). Hicromitra (Paterina) bella. Botsfordia cselata. Micromitra (Paterina) labradorica. Yorkia wanneri?. Bicia gemma. Nisusia festinata. Kutorgina cingulata. Discinella sp. Obolella crassa. 2p (see 2o and 2r). Lower Cambrian: Limestone on south side of the road a little west of Bic and half a mile (0.8 km.) west of the road leading to the wharf, Rimouski County, Quebec, Canada (C. D. Walcott, 1899). Bicia gemma. Botsfordia cselata. 2r (see 2o and 2p). Lower Cambrian: Limestone bowlders in a conglomerate in a cut on the Intercolonial Rail- way, 2 miles (3.2 km.) west of Bic railway station, Rimouski County, Quebec, Canada (C. D. Walcott, 1899). *Micromitra nisus. I Botsfordia caslata. Micromitra (Paterina) labradorica?. | Callavia bicensis Walcott. 2s (see2t). (For stratigraphic position and association, see p. 132.) Middle Cambrian: Limestone in upper part oi Paradoxides zone, at Hastings Cove [see Matthew, 1898b, p. 38], on Kennebecasis Bay, 0.5 mile ("O.R km.) northeast of Torryburn, on the Intercolonial Railway, northeast of St. John, St. John County, New Bruns- wick (C. D. Walcott, 1899). Lingulella ferruginea. Acrothele matthewi. Acrothele matthewi multicostata. *Acrotreta gracia. Acrotreta misera. Acrotreta sagittalis. *Acrotreta sagittalis magna. Billingsella coloradoensis. Billingsella sp. Eoorthie hastingsensis. 164 CMIBEIAN BKACHIOPODA. Matthew cites the following additional species from this localit}': Indiana priniEeva (Matthew). Indiana dermatoides (Walcott). 2t (shale in which limestone of 2s is interbedded). (For stratigraphic position and association, see p. 132.) Middle Cambrian: Shales in upper part of Paradoxides zone, at Hastings Cove [see Matthew, 1898b, p. 38], on Kennebecasis Bay, 0.5 mile (0.8 km.) northeast of Torryburn, on the Intercolonial Railway, northeast of St. John, St. John County, New Brunswick (C. D. Walcott, 1899). *Acrothele matthewi multicostata. Acrotreta misera. 2u (below 2x; see 308g). (For stratigraphic position and association, see p. 132.) Middle Cambrian: Lowes beds exposed on the south side of Long Island, Kennebecasis Bay [see Matthew, 1898a, pp. 124 and 127], St. John County, New Brunswick (C. I). Walcott, 1899). Trematobolus kempanum. *Protorthis helena. Protorthis (Loperia) dugaldensis. 2x (=locality given by Matthew [1892, p. 59]; a higher horizon than 2u). (For stratigraphic position and associa- tion, seep. 131.) Upper Cambrian: Thin-bedded sandstones of Division 2 of Matthew [1892, p. 59], on the south shore of Long Island, Kennebecasis Bay [see Matthew, 1898a, pp. 124 and 127], St. John County New Brunswick (C. D. Walcott, 1899). *Lingulella minor. Lingulella minor?. Lingulella (Lingulepis) starri. 2y. (For stratigraphic position and association, see p. 133.) Middle Cambrian: Sandstone about 25 feet (7.6 m.) above the Lower Cambrian, on the southeast side of Catons Island, in Long Reach, St. John River, Kings County, New Brunswick (C. D. Walcott, 1899). Botsfordia pulchra. 2z. (For stratigraphic position and association, see p. 147.) Middle Cambrian: Nolichucky(?) shale [Campbell, 1899, p. 3], near Shipley Ferry, 0.75 mile (1.2 km.) northwest of Bethany Chapel, northeastern corner of the Roan Mountain quadrangle (U. S. G. S.), Sullivan County, Tenn. (M. R. Campbell, 1894). Dicellomus appalachia. 2z'. (For stratigraphic position and association, see p. 147.) Middle Cambrian: Shales in the Honaker limestone [Campbell, 1899, p. 3], at Wallace switch, about 5 miles (8 km.) northeast of Bristol, Bristol quadrangle (U. S. G. S.), Sullivan County, Tenn. (T. C. Mendenhall and M. R. Campbell, 1894). Dicellomus appalachia. 3 (highest horizon on Manuels Brook). (For stratigraphic position and association, see p. 140.) Upper Cambrian: Shaly limestones 300 feet (91.4 m.) above the Paradoxides zone, Manuels Brook, Conception Bay, New- foundland (C. D. Walcott, 1888). Lingulella ferruginea. I Acrotreta sagittalis transversa. Acrothele matthewi. I Orusia lenticularis. 3a. Lower Cambrian: 450 feet (137.1 m.) below the quartzite ia the St. John formation and over 500 feet (152.4 m.) below the Protolenus fauna of Matthew [see Walcott, 1900, pp. 320-322], Hanford Brook, St. John County, New Brunswick (C. D. Walcott, 1899). Micromitra (Paterina) labradorica. 3b (see 2e). (For stratigraphic position and associatipn, see p. 132.) Middle Cambrian: Shale at the base of the Paradoxides zone, head of Seeley Street, St. John, St. John County, New Brunswick (S. W. Loper, 1899). Acrothele matthewi. Protorthis billingsi. Protorthis quacoensis. 3c. (For stratigraphic position and association, see p. 158.) Middle Cambrian: Shales abo\it 75 feet (22.9 m.) above the quartzitic sandstones of the Cambrian, at Ophir, Oquirrh Range, Tooele County, LTtah (H. E. Dickhaut, 1900). Obolus (Westonia) ella. 3d. (For stratigraphic position and association, see p. 157.) Middle Cambrian: Concretionary limestone about 100 feet (30.5 m.) above the quartzitic sandstones of the Cambrian, at Ophir, Oquirrh Range, Tooele County, Utah (H. E. Dickhaut, 1900). Micromitra sp. ' I Obolus (Westonia) ella. Micromitra (Paterina) labradorica utahensis. | Olenoides?. LOCALITIES. 165 3e. (For stratigraphic position and association, see p. 156.) Middle Cambrian; Thin-bedded limestone less than 400 feet (121.9 m.) above the quartzitic sandstones of the Cambrian, at Ophir, Oquirrh Range, Tooele County, Utah (H. E. Dickhaut, 1900). Micromitra sp. *Micromitra (Iphidella) pannula ophirensis. Obolus matinalis. Obolus tetonensis. Lingulella arguta. *Acrothele subsidua Isevis. *Acrotreta ophirensis. *Acrotreta ophirensis rugosa. Olenoides?. 3g (see 360h). Middle Cambrian: Shales on river bank 250 feet (76.2 m.) above west end of Denver and Rio Grande Railway tunnel, Glenwood Springs, Garfield County, Colo. Obolus (Westonia) ella. Lingulella sp. 31i. (For stratigraphic position and association, see p. 131.) Upper Cambrian: Shale and shaly limestone, on McNeil Brook, 1.5 miles (2.4 km.) east of Marion Bridge, Cape Breton, Nova Scotia (S. W. Loper, 1900). *Obolus acadicus. Obolus (Broggeria) salteri. Lingulella concinna. Lingulella ferruginea. Schizambon priscus. Si. (For stratigraphic position and association, see p. 132.) Middle Cambrian: Compact, fine-grained, thm-bedded gray sandstone of the Paradoxides zone, on McLean Brook, 1 mile (1.6 km.) east of McCodrum Brook and 1.5 miles (2.4 km.) west of Marion Bridge, Cape Breton, Nova Scotia (S. W. Loper, 1900). Matthew [1903, p. 195] says the horizon is his Dixosion C2b. Lingulella rotunda. *Lingulella (Lingulepis) exigua. Acrothyra proavia. *Lingulella cania. Lingulella concinna. Lingulella ferruginea. 3j (same locality as 5j, but 25 feet above; see 4v and 4q). Middle Cambrian: Above the quartzitic sandstones, in a shale corresponding in position to the upper part of shale No. 6 of the Dearborn River section fW'alcott, 1908f, p. 202], about 6 miles (9.6 km.) west-northwest of Scapegoat Mountain, on the Continental Divide between Bar Creek and the headwaters of the south fork of the North Fork of Sun River, Coopers Lake quadrangle (U. S. G. S.) Powell County, Mont. (C. D. Walcott, 1905). Obolus mcconnelli. Bathyuriscus productus (Hall and Whitfield). 3n. (For stratigraphic position and association, seep. 131.) Upper Cambrian: Thin-bedded sandstone on Salmon River, Gillis Hill, 13 miles (20.9 km.) south of Marion Bridge, eastern Cape Breton, Nova Scotia (S. W. Loper, 1900). Lingulella minor. I *Acrotreta convexa. Lingulella (Lingulepis) exigua. | 3o (see "372c). (For stratigraphic position and association, see p. 131.) Upper Cambrian: Shales in the first ravine south of the post office at Barachois, east of Little Bras d'Or Lake, eastern Cape Breton, Nova Scotia (S. W. Loper, 1900). , Lingulella concinna. 3p. (For stratigraphic position and association, see p. 131.) Upper Cambrian: Shales in ravine 0.5 mile (0.8 km.) north of McMullins, on the crossroad to Boisdale station, eastern Cape Breton, Nova Scotia (S. W. Loper, 1900). Lingulella concinna. 3q. (For stratigraphic position and association, see p. 131.) Upper Cambrian ; Shale in Barachois Glen, 4 miles (6.4 km.) south of Little Bras d'Or Lake, eastern Cape Breton, Nova Scotia (S. W. Loper, 1900). Obolus (Broggeria) salteri. I Schizambon priscus. Lingulella concinna. I Acrotreta bisecta. 3s (same horizon as Iz, 4, and 15b; =3t and 8g). (For stratigraphic position and association, see p. 156.) Middle Cambrian: About 1,700 feet (518.2 m.) above the Lower Cambrian and 2,700 feet (823 m.) below the Upper Cambrian, in the shaly limestones and calcareous shales of the Wheeler formation [Walcott, 1908f, p. 181], in the eastern part of Wheeler Amphitheater, east of Antelope Springs, House Range [Walcott, 1908f, Pis. XIII and XV], Millard County, Utah (C. D. Walcott, F. B. Weeks, and L. D. Burling, 1903 and 1905). Obolus mcconnelli pelias. Ptychoparia kingi (Meek). Acrothele subsidua. Ptychoparia sp. Acrotreta attenuata. Asaphiscus wheeleri (Meek). Agnostus bidens (Meek). 166 CAMBRIAN BEACHIOPODA. 3t (=3s, which see). (For stratigraphic position and association, see p. 156.) 3v. (For stratigraphic position and association, see p. 158.) Middle Cambrian: About 200 feet (61 m.) above the Lower Cambrian in the " Spence shale " [Walcott, 1908f, p. 183] (described in this monograph, p. 158, as Ih of the Howell formation), in Dome Canyon, about 5 miles (8 km.) west of Antelope Springs, House Range [Walcott, 1908f, PI. XIII], Millard County, Utah. (See p. 158 for list of species.) 3w (same horizon as 30g and llq). (For stratigraphic position and association, see p. 156.) Middle Cambrian: About 2,350 feet (716.3 m.) above the Lower Cambrian and 2,050 feet (624.8 m.) below the Upper Cambrian, in the central portion of the thin-bedded limestones forming Ic of the Marjum limestone [Walcott, 1908f, p. 180], in the cliff about 2 miles (8.2 km.) southeast of Marjum Pass, House Range [see Walcott, 1908f, Pis. XIII and XV], Millard County, Utah (C. D. Walcott, 1903). Lingulella arguta. I Ptychoparia. Acrotreta bellatula. I Neolenus. 3x (=llx). (For stratigraphic position and association, see p. 156.) Middle Cambrian: About 2,200 feet (670.6 m.) above the Lower Cambrian and 2,200 feet (670.6 m.) below the LTpper Cambrian, in the limestones forming Id of the Marjum limestone [Walcott, 1908f, p. 180], 2.5 miles (4 km.) east of Antelope Springs, in ridge east of WTieeler Amphitheater, House Range [^^alcott, 1908f, Pis. XIII and XV], Millard County, Utah (C. D. Walcott, F. B. Weeks, and L. D. Burlins. 1905}. Micromitra sculptilis. Micromitra (Iphidella) pannula ophtrensis Obolus mcconnelli pelias. Obolus rotundatus. Lingulella arguta. Acrothele subsidua. Acrothele subsidua Isevis. Acrotreta attenuata. Acrotreta ophirensis. Eoorthis remnicha?. *Eoorthis thyone. *Syntrophia? unxia. Agnostus 3 sp. Ptychoparia. Neolenus inflatus Walcott. Neolenus intermedius Walcott. Neolenus superbus Walcott. Ogygopsis?. 3y. (For stratigraphic position and association, see p. 156.) Middle Cambrian: About 2,150 feet (655.3 m.) above the Lower Cambrian and 2,250 (685.8 m.) below the Upper Cambrian, in the shaly limestones forming Id of the Marjum limestone [Walcott, 1908f, p. 180], 2.5 miles (4 km.) east of Antelope Springs, in ridge east of "ttTieeler Amphitheater, House Range [Walcott, 1908f, Pis. XIII and XV], Millaid County, Utah(C. D. Wal- cott, F. B. Weeks, and L. D. Burling, 1905). Obolus mcconnelli pelias. Ptychoparia. Acrotreta ophirensis. Ogygopsis?. Agnostus. i (same horizon as 3s). (For stratigraphic position and association, see p. 156.) Middle Cambrian: Drift pieces believed to have come from the ^\Tieeler formation [Walcott, 1908f, p. 181], collected near Antelope Springs, House Range [Walcott, 1908f, PL XIII], Millard County, Utah (.1. F. Gibbs, 1889). *Acrothele subsidua. I Ptychoparia kingi (Meek). Agnostus interstrictus White. | Asaphiscus wheeleri (Meek). 4e (see 4m and 4n). Middle Cambrian: Limestones about 950 feet (289.6 m.) above the unconformable base of the Cambrian, in the divide at head of Jackson Creek (locally known as Sheep Creek), a creek flowing into Jack- son Lake about 0.5 mile (0.8 km.) south of its northwestern corner, Teton Mountains, Grand Teton quadrangle (U. S. G. S.), Uinta County, Wyo. (C. D. Walcott, 1898). *Obolus tetonensis. I *Acrotreta microscopica tetonensis. Lingulella (Lingulepis) acuminata meeki. | Billingsella coloradoensis. (Possibly the last named is from a bed different from that containing the other species.) 4g (50 feet below 4h; see 4h, 4k, and 4p). Middle Cambrian: About 325 feet (99.1 m.) above the base of the Cam- brian, in the Flathead shales of Peale [1893, p. 21], 1 mile (1.6 km.) north of the junction of East Gallatin and West Gallatin (Gallatin) rivers, 4 miles (6.4 km.) eaat-northeast of Logan, Threeforks quadrangle (U. S. G. S.), Gallatin County, Mont. (C. D. Walcott). Obolus (Westonia) ella. 411 (50 feet above 4g; see 4g, 4k, and 4p). Middle Cambrian: About 375 feet (114.3 m.) above the base of the Cam- brian, in limestone interbedded in the Flathead shales of Peale [1893, p. 21], 1 mile (1.6 km.) north of the junction of Ea^t Gallatin and West Gallatin (Gallatin) rivers, 4 miles (6.4 km.) east-northeast of Logan, Threeforks quadrangle (U. S. G. S.), Gallatin County, Mont. (C. D. Walcott). Micromitra pealei. I Lingulella (Lingulepis) acuminata meeki. Obolus tetonensis. I Acrotreta pyxidicula. LOCALITIES. 167 4j. Middle Cambrian: Limestone at the head of Deep Creek, Canyon quadrangle (U. S. G. S.), Yellowstone National Park, Wyo. Billingsella plicatella. Eoorthia sp. *Huenella abnormis. The first and third of these fossils may not have been collected from the same bed. 4k (4i is limestone interbedded in these shales; see 4g, 4h, and 4p). Middle Cambrian: About 725 feet (221 m.) above the base of the Cambrian, in the shales of the Gallatin formation of Peale [1893, PI. IV], on the north side of West Gallatin (Gallatin) River, northeast of Logan, Threeforks quadrangle (U. S. G. S.), Gallatin County, Mont. (C. D. Walcott, 1898). Obolus (Westonia) ella. 41. (For stratigraphic position and association, see pp. 140 and 158.) Lower Cambrian: Limestone in the equiv- alent of the Pioche formation at Pioche and in the House Range [Walcott, 1908a, p. 11], on a rid^e 2.5 miles (4 km.) northwest of the town of Cherry Creek, White Pine County, Nev. (0. H. Hershey). Micromitra (Iphidella) pannula. Acrotreta claytoni. Acrotreta primaeva. 4m. (about 175 feet below 4n). Middle Cambrian: Sandstones about 150 feet (45.7 m.) above the unconformable base of the Cambrian, in the divide at the head of Jackson Creek (locally known as Sheep Creek), a creek flowing into Jackson Lake about 0.5 mile (0.8 km.) south of its northwestern corner, Teton Mountains, Grand Teton quadrangle (U. S. G. S.), Uinta County, Wyo. (C. D. Walcott, 1898). Obolus tetonensis. 4n (about 175 feet above 4m). Middle Cambrian: Limestone about 325 feet (99.1 m.) above the unconformable base of the Cambrian, in divide at the head of Jackson Creek (locally known as Sheep Creek), a creek flowing into Jackson Lake about 0.5 mile (0.8 km.) south of its northwestern corner, Teton Mountains, Grand Teton quadrangle (U. S. G. S.), Uinta County, Wyo. (C. D. Walcott and F. B. Weeks, 1898). Micromitra pealei. I Lingulella helena. Obolus (Westonia) ella. I Acrotreta attenuata. M. pealei also occurs in locality 4n', which is probably a slightly different bed at the locality given for 4n. 4o (about 50 feet above 4n). Middle Cambrian: Shale about 375 feet (115 m.) above the unconformable base of the Cambrian, in di\dde at the head of Jackson Creek (locally known as Sheep Creek), a creek flowing into Jackson Lake about 0.5 mile (0.8 km.) south of its northwestern corner, Teton Mountains, Grand Teton quadrangle (U. S. G. S.), Uinta County, Wyo. (C. T>. Walcott, 1898). Acrotreta definita. 4p (see 4g, 4h, and 4k). Middle Cambrian: About 225 feet (68.6 m.) above the base of the Cambrian, in lime- stones interbedded in the Flathead shales of Peale [1893, p. 21], on the north side of West Gallatin (Gal- latin) River, 2 miles (3.2 km.) northeast of Logan, Threeforks quadrangle (U. S. G. S.), Gallatin County, Mont. (C. D. Walcott, 1898). Micromitra pealei. 44 (115 feet above 4v; see 3j and 4v). Middle Cambrian: About 315 feet (96 m.) above the unconformable base of the Cambrian and 190 feet (57.9 m.) above the top of the quartzitic .sandstones, in a shale which corre- sponds in position to the upper part of shale No. 6 of the Dearborn River section [see Walcott, 1908f, p. 202], on the ridge between Gordon and Youngs creeks, about halfway between Gordon Mountain and Car- dinal Peak, Ovando quadrangle (U. S. G. S.), Powell County, Mont. (C. D. Walcott, 1905). Ptychopai'ia 3 sp. Bathyuriscus productus (Hall and Whitfleld). Zacanthoides. *Mic'romitra (Iphidella) nyssa. Micromitra (Iphidella) pannula. *Acrothele colleni. Wimanella simplex. 4q' (just below 4q; see 3j, 4q, and 4v). Middle Cambrian: Limestone about 310 feet (94.5 m.) above the uncon- formable base of the Cambrian and 185 feet (56.4 m.) above the top of the quartzitic sandstones, in a shale which corresponds in position to the upper part of shale No. 6 of the Dearborn River section [see Walcott, 1908f, p. 202], on the ridge between Gordon and Youngs creeks, about halfway between Gordon Mountain and Cardinal Peak, Ovando quadrangle (U. S. G. S.), Powell County, Mont. (C. D. Walcott, 1905). Micromitra (Iphidella) pannula. Obolus (Westonia) ella. 4r. Upper Cambrian: Just above the Middle Cambrian, in the limestones of the Gallatin formation of Peale [1893, PI. IV], on a ridge 8 miles (12.8 km.) east of Yellowstone River and 3 miles (4.8 km.) north- northeast of Mount Delano, Livingston quadrangle (U. S. G. S.), Park County, Mont. (C. D. Walcott, 1 898). Eoorthis renmicha. 168 CMIBRIAN BRACHIOPODA. 4u. Middle Cambrian: Shales in the Gallatin formation of Peale [1893, PI. IV], northwest side of canyon, 0.5 mile (0.8 km.) south of Helena, Jefferson County, Mont. (L. S. Griswold and C. D. Walcott, 1898). Obolus (Westonia) ella. Lingulella helena. 4v (115 feet below 4q; same horizon as 5j; see 3j and 4q). Lower Cambrian: About 200 feet (61 m.) above the unconformable base of the Cambrian and 75 feet (22.9 m.) above the top of the quartzitic sandstones, in a shale which corresponds in stratigraphic position to shale No. 6 of the Dearborn River section [see Walcott, 1908f, p. 202], Gordon Creek, 6 miles (9.6 km.) from South Fork of Flathead River, Ovando quadrangle (U. S. G. S.), Powell County, Mont. (C. D. Walcott, 1905). Micromitra (Iphidella) pannula. Obolus (Westonia) ella. Acrothele coUeni. *Acrothele panderi. *Wimanella simplex Ptychoparia sp. Olenopsis? sp. Albertella helena Walcott. Bathyuriscus productus (Hall and Whitfield)?. Bathyuriscus? sp. 4-w (same horizon as 4q). Lower Cambrian: About 315 feet (96 m.) above the unconformable base of the Cambrian and 190 feet (57,9 m.) above the top of the quartzitic sandstones, in a shale which corresponds in position to shale No. 6 of the Dearborn River section [see Walcott, 1908f, p. 202], on Youngs Creek, about 5 miles (8 km.) from its junction with Danaher Creek, Ovando quadrangle (U. S. G. S.), Powell County, Mont. (C. D. Walcott, 1905). Wimanella simplex. Ptychoparia sp. Zacanthoides sp. 4x (a little higher than 5f; see 4g 4h, 4k, and 5f). Middle Cambrian: Limestone interbedded in the Wolsey shale [Weedl'igOO, p. 285], at the base of a butte in Belt Park, about 6 miles (9.6 km.) northwest of Neihart, Little* Belt Mountains quadrangle (U. S. G. S.), Cascade County, Mont. (C. D. Walcott, 1898). Micromitra pealei. Obolus tetonensis. Scenella. 4y (= 54t, which see). (For stratigraphic position and association, see p. 149.) (C. D. Walcott, 1898.) Obolus (Westonia) ella. Billingsella coloradoensis. 5. Middle Cambrian: Siliceous shale on Hayward Creek, Braintree, Dedham quadrangle (U. S. G. S.), Norfolk County, Mass. (W. P. Rust, 1891). Acrothele gamagei. I Agraulos quadrangularis (^^^litfield). Hyolithes shaleri Walcott. I Paradoxides harlani Green. Grabau [1900] cites the following additional species from this locality: Fucoids or trails?. 1 Hyolithes ? haywardensis Grabau. Parmophorella acadica (Hartt). I Ptychoparia rogersi Walcott. 8a (=54t, which see). (For stratigraphic position and associatioit, see p. 149.) (C. D. Walcott, 1898.) Obolus wortheni. Lingulella desiderata. Billingsella coloradoensis. 5b (=54s, which see). (For stratigraphic position and association, see p. 152.) (C. D. Walcott, 1893.) For the species occurring at this locality, see Locality 548. 5c (=54t, which see). (For stratigraphic position and association, see p. 149.) (C. D. Walcott and L. D. Burling, 1906.) Obolus wortheni. *Acrotreta idahoensis. Billingsella coloradoensis. 51 (a little lower than 4x), Middle Cambrian: Limestone interbedded in the Wolsey shale [Weed, 1900, p. 285], in Meagher County, on the road to Wolsey, about 4 miles (6.4 km.) south of the divide at the head of Saw. ' mill Creek and 11 miles (17.7 km.) south of Neihart, Little Belt Mountains quadrangle (U. S. G. S.), Cascade County, Mont. (C. D. Walcott, 1898). Micromitra pealei. Obolus (Westonia) ella. Lingulella desiderata. Scenella. Dorypyge? quadriceps (Hall and Whitfield). LOCALITIES. 169 Sh (=55d, which see). (For stratigraphic position and association, see p. 150.) (C. D. Walcott, 1898.) Obelus (Westonia) ella. 5] (same horizon as 4v; same locality as 3j but 2.5 feet below). Lower Cambrian: Above the quartzitic sand- stones, in a shale which corresponds in position to shale No. 6 of the Dearborn River section [see Walcott, 1908f, p. 202], about 6 miles (9.6 km.) west-northwest of Scapegoat Mountain, on the Continental Divide between Bar Creek and the headwaters of the south fork of North Fork of Sun River, Coopers Lake quad- rangle (U. S. G. S.), Powell County, Mont. (C. D. Walcott, 1905). Acrothele panderi. Albertella helena Walcott. 5k. Middle Cambrian: Limestone in Meagher County, on the road to Wolsey, about 1 mile (1.6 km.) south of the divide at the head of Sawmill Creek and 8 miles (12.8 km.) south of Neihart, Little Belt Mountains quad- rangle (U. S. G. S.), Cascade County, Mont. (C. D. Walcott, W. H. Weed, and F. B. Weeks, 1895). Micromitra sp. 1 *Schuchertina Cambria. Dicellomus politus. j Billingsella coloradoensis. 5 1 (50 feet below 5n at same locality; same horizon as 5p and 41), (For stratigraphic position and association, see p. 141.) Lower Cambrian: Limestone on Smith Point, in Smith Sound, Trinity Bay, Newfoundland (C. D. Walcott, 1899). Micromitra (Paterina) labradorica. OleneUus?. 5n (50 feet above 51 at same locality; 275 feet below 5o). (For stratigraphic position and association, see p. 141.) Lower Cambrian: Shale on Smith Point, in Smith Sound, Trinity Bay, Newfoundland (C. D. Walcott, 1899). Obolella atlantica. Callavia broggeri (Walcott). 5o (about 275 feet above 5n; see 51 and on). (For stratigraphic position and association, see p. 141.) Lower Cambrian: Just below the Middle Cambrian, in shales on Smith Point, in Smith Sound, Trinity Bay, New- foundland (S. W. Loper and C. D. Walcott, 1899). Obolella atlantica. OleneUus?. 5p (same horizon as 51 and 41). (For stratigraphic position and association, see p. 141.) Lower Cambrian: Lime- stone 300 feet (91.4 m.) southeast of the railway station, Manuels, Conception Bay, Newfoundland (C. D. Walcott, 1899). Obolella atlantica. Callavia broggeri (Walcott). 5r. (For stratigraphic position and association, see p. 141.) Lower Cambrian: Limestone near the railroad track, 1.5 miles (2.4 km.) west of the railway station at Manuels, Conception Bay, Newfoundland (C. D. Walcott, 1899). Micromitra (Paterina) labradorica. Callavia broggeri (Walcott). 5t. (For stratigraphic position and association, seep. 141.) Lower Cambrian: Shale and limestone nodules about 20 feet (6 m.) above the base of the Cambrian, on Redrock Point, near Chappie Cove, Hollywood Point, Con- ception Bay, Newfoundland (J. P. Howley and C. D. Walcott, 1899). Micromitra (Paterina) labradorica. Obolella atlantica. Callavia broggeri (Walcott). 6g. (For stratigraphic position and association, see p. 141.) Middle Cambrian: Limestone near the base of the Middle Cambrian, the lowest horizon carrying Paradoxides, northwest side of Chappie Arm Harbor, about 1 mile (1.6 km.) from its head, Trinity Bay, Newfoundland (J. P. Howley and C. D. Walcott, 1899). Micromitra (Iphidella) ornatella. Micromitra (Iphidella) pannula maladensis. Lingulella ferruginea. Acrothele matthewi. Acrotreta misera. Acrotreta sagittalis. 6h. (For stratigraphic position and association, see p. 140.) Middle Cambrian: Limestone in the southwest cove of Chappie Arm, Trinity Bay, Newfoundland (C. D. Walcott, 1899). Acrotreta misera. 170 CAiMBRIAN BRACHIOPODA. 6i (280 feet below 6s). (For stratigraphic position and association, see p. 140.) Middle Cambrian: Limestone about 300 feet (91.4 m.) below the base of the Upper Cambrian, on shore north of Fosters Point, Random Island, Random Sound, Newfoundland (C. D. Walcott, 1899). Acrotreta sagittalis. Agnostus. Microdiscus. 61 (=la, except that the fossils were collected on the east side of the brook). (For stratigraphic position and association, see p. 140.) (C. D. Walcott, 1899.) Lingulella ferruginea. I Acrotreta?. Acrothele matthewi. | *Eoorthis papias. 6n (=la, except that the fossils were collected on the west side of the brook). (For stratigraphic position and association, see p. 140.) (C. D. Walcott, 1899.) Lingulella ferruginea, Acrothele matthewi. Acrothele prima costata. 6r. (For stratigraphic position and association, see p. 140.) Middle Cambrian: Limestone on the west side of Manuels Brook, Conception Bay, Newfoundland (C. D. Walcott, 1899). Lingulella ferruginea. Acrotreta misera. 6s (=6u; 280 feet above 6i). (For stratigraphic position and association, see p. 140.) Upper Cambrian: Just north of Fosters Point, Random Island, Random Sound, Newfoundland (C. D. Walcott, 1899). Lingulella ferruginea?. 6u (same horizon as 6s). (For stratigraphic position and association, see p. 140.) Upper Cambrian: Shale on the west side of Manuels Brook, Conception Bay, Newfoundland (C. D. Walcott, 1899). Lingulella ferruginea. 6v (375 feet above 6n). (For stratigraphic position and association, see p. 140.) Upper Cambrian: Shaly lime- stones 325 feet (99.1 m.) above the Middle Cambrian, Manuels Brook, Conception Bay, Newfoundland (C. D. Walcott, 1899). Onisia lenticularis. 6w. (For stratigraphic position and association, see p. 140.) Middle Cambrian : Limestone at Seal Point Cove, near Long Point, Trinity Bay, Newfoundland (C. B. Walcott, S. W. Loper, and J. P. Howley, 1899). Acrotreta sagittalis. 6y. (For stratigraphic position and association, see p. 140.) Upper Cambrian: Sandstone on north side of Random Island, between Birch and Sandy points, Smith Sound, Trinity Bay, Newfoundland (C. D. Walcott and S. W. Loper, 1899). *Lingulella randomensis. 7. (For stratigraphic position and association, see p. 138.) Lower Cambrian: Shaly beds about 1,000 feet (305 m.) above the quartzitic beds, Silver Canyon, \ATiite Mountain Range, Inyo County, Cal. (C. D. Walcott, 1894). Kutorgina perugata. Yorkia wanneri?. 7d. (For stratigraphic position and association, see p. 147.) Upper Cambrian: Shales in second cliff, 0.125 mile (0.2 km.) west of Peak post office, 3 miles (4.8 km.) south of Clinton, Briceville quadrangle (U. S. G. S.), Anderson County, Tenn. Obelus lamborni. Lingulella ino. 7i. (For stratigraphic position and association, see p. 139.) Middle Cambrian: Limestone just west of the summit, on the road east of Schellbom-ne, Schell Creek Range, ^"hite Pine County, Nev. (J. E. Spurr, 1899). Obolus rotundatus. I Lingulella punctata. Lingulella manticula. | Acrotreta idahoensis alta. 7j. Middle Cambrian: Limestones at the north end of the Quinn Canyon Range, 1 mile (1.6 km.) northwest of the Italian Ranch foothills, Nye County, Nev. (J. E. Spurr, Micromitra 2 sp. undt. Obolus rotundatus. Lingulella manticula. "Lingulella similis. Fossils marked ° may not all be from the same bed or even from the same approximate stratigraphic horizon. *Acrotreta cf . idahoensis. "Acrotreta primseva?. "Acrotreta pyxidicula. LOCALITIES. 171 7k (see 31 and 333b). (For stratigraphic position and association, see p. 158.) Middle Cambrian: Shales in the dumps of the Half-moon and Chisholm mines, southwest slope of Ely Mountains, 3 miles (4.8 km.) north- west of Pioche, Lincoln County, Nev. (J. E. Spurr, 1899). Obolus (Westonia) ella. 7n. Upper? Cambrian: Limestone at Hornet Spring in the Spring Mountain. Range, on the road from Indian Spring to Pahrump Valley, Lincoln County, Nev. (J. E. Spm-r, 1899). *Obolus sp. undt. b. 7r (see 7s and 7v). Middle Cambrian: Calcareous shales 4 miles (6.4 km.) south-southeast of Emigrant Peak, Silver Peak quadrangle (U. S. G. S.), Esmeralda County, Nev. (H. W. Tm-ner, 1899). Obolus mcconnelli decipiens. *Acrothele turneri. 7s (see 7r and 7v). Upper Cambrian: Shales of the Emigrant formation [Turner, 1902, p. 265], 4 miles (6.4 km.) south-southeast of Emigrant Peak, Silver Peak quadrangle (U. S. G. S.), Esmeralda County, Nev. (H. W. Turner, 1899). Obolus mcconnelli pelias. 7v (see 7r and 7s). ITpper Cambrian: Shales of the Emigrant formation [Turner, 1902, p. 265], 4.25 miles (6.8 km.) south-southeast of Emigrant Peak, Silver Peak quadrangle (U. S. G. S.), Esmeralda County, Nev. (H. W. Turner, 1899). *Obolus mcconnelli decipiens. Acrotreta argenta. 7w. (For stratigraphic position and association, see p. 156.) Middle Cambrian: Limestone in Rock Canyon in the Wasatch Mountains, east of Provo, ITtah County, Utah (G. H. Girty, 1900). ^Nisusia (Jamesella) utahensis. Dorypyge?. 7x (=7y; 50 feet below 8a). Upper Cambrian: Limestone of the Emigrant formation [Turner, 1902, p. 265], about 2.5 miles (4 km.) southeast of Emigrant Pass, Silver Peak quadrangle (U. S. G. S.), Esmeralda County, Nev. (F. B. Weeks, 1900). LinguleUa (Lingulepis) acuminata. Acrotreta argenta. Menocephalus sp. Obolus mcconnelli decipiens. * Obolus (Fordinia) bellulus. LinguleUa desiderata. 7y (=7x, which see). (F. B. Weeks, 1900.) Obolus (Fordinia) bellulus. Acrotreta argenta. LinguleUa desiderata. Menocephalus. LinguleUa (Lingulepis) acuminata. 7z. Upper Cambrian: Limestone of the Emigrant formation [Turner, 1902, p. 265], about 3 miles (4.8 km.) south- east of Emigrant Pass, Silver Peak quadrangle (U. S. G. S.), Esmeralda County, Nev. (F. B. Weeks, 1900). Obolus (Fordinia) bellulus. LinguleUa desiderata. LinguleUa (Lingulepis) acuminata. 8a (50 feet above 7x). Upper Cambrian: Shaly limestones of the Emigrant formation [Turner, 1902, p. 26}], 2 miles (3.2 km.) southeast of Emigrant Pass, Silver Peak quadrangle (U. S. G. S.), Esmeralda County, Nev. (F. B. Weeks, 1900). OfcoleUa?. 8b. Lower Cambrian: Limestone in Tollgate Canyon, about 15 miles (24.1 km.) east of \Yhite Pine, '^Tiite Moun- tain Range, Inyo County, Cal. (C. D. Walcott, 1894). Kutorgina sp. OboleUa vermUionensis. ■*WimaneUa inyoensis. 8b'. Upper Cambrian: Shales of the Emigrant formation [Turner, 1902, p. 265], in a ravine on the east side of the road about 1 mile (1.6 km.) southwest of Emigrant Pass, Silver Peak quadrangle (U. S. G. S.), Esmeralda County, Nev. (F. B. Weeks, 1900). ■* Acrotreta argenta. 8d (see 372). (For stratigraphic position and association, see p. ,131.) Upper Cambrian: Shales at Upper Leitches Creek, eastern Cape Breton, Nova Scotia (S. W. Loper, 1330). LinguleUa concinna. 172 CMIBRIAN BRACHIOPODA. 8e. (For stratigraphic position and association, see p. 139.) Upper Cambrian: Limestone in Patterson Canyon, west side of the Schell Creek Range, ^Miite Pine County, Nev. (F. B. Weeks, 1900). Lingulella manticula. 8f. (For stratigraphic position and association, see p. 139.) Upper Cambrian: Limestone at summit of canyon 10 miles (16.1 km.) south of Egan Canyon, east side of Egan Range, '\^Tiite Pine County, Nev. (F. B. Weeks, 1900). Obolus discoideus. I Lingulella punctata. Lingulella manticula. | Eoorthis?. 8g (=3s and 3t, which see). (For stratigraphic position and association, see p. 156.) (F. B. Weeks, 1900.) Obolus mcconnelli pelias. Acrothele subsidua. 8i. (For stratigraphic position and association, see p. 156.) Middle Cambrian: Shales believed to be referable to the lower portion of the ilarjum limestone [Walcott, 1908f, p. 180], found about 0.5 mile (0.8 km.) east of Antelope Springs, House Range [Walcott, 1908f, PI. XIII], Millard County, Utah (F. B. Weeks, 1900). Micromitra sculptilis. Obolus mcconnelli pelias. Kutorgina sp. 8j. Middle Cambrian: About 575 feet (175.3 m.) above the unconformable base of the Cambrian, in a shale which corresponds in position to shale No. 4 of the Dearborn River section [see Walcott, 1908f, p. 202], on the ridge between Gordon and Youngs creeks, about halfway between Gordon Mountain and Cardinal Peak, Ovando quadrangle (U. S. G. S.), Powell County, Mont. (C. D. Walcott, 1905). Micromitra (Paterina) superba. Ptychoparia sp. Obolus mcconnelli pelias. Zacanthoides sp. Bathyuriscus productus? (Hall and Whitfield). 8k. (For stratigraphic position and association, seep. 156.) Middle Cambrian: Shales 0.5 mile (0.8 km.) northwest of Tyler Springs, east slope of House Range, east of Antelope Springs [Walcott, 1908f, PI. XIII], Millard County, Utah (F. B. Weeks, 1900). Obolus mcconnelli peliaa. 8m. (For stratigraphic position and association, seep. 139.) Middle Cambrian: Limestone near the south end of the high ridge 4 miles (6.4 km.) northeast of Osceola, White Pine County, Nev. (F. B. Weeks, 1900). Obolus mcconnelli. Obolus mcconnelli decipiens. Sn. (For stratigraphic position and association, seep. 139.) Upper Cambrian: Limestone about 500 feet (152 m.) up in the Cambrian limestones east of Swallow ranch, west side of the Snake Range, 20 miles (32.2 km.) south of Osceola, ^Yhite Pine County, Nev. (F. B. Weeks, 1900). Lingulella desiderata. 8o. (For stratigraphic position and association, seep. 139.) Upper Cambrian: Limestone on the slope of the ridge where the range swings around to the northwest, 2 miles (3.2 km.) north of Aurum, Schell Creek Range,. "RTiite Pine County, Nev. (F. B. Weeks, 1900). * Micromitra sculptUis endJichi. Micromitra sp. Obolus rotundatus. Lingulella punctata. Acrotreta microscopica. Eoorthis sp. 8p. (For stratigraphic position and association, see p. 139.) Upper Cambrian: Limestone halfway up the canyon- east of McGill's ranch, on the west side of the Schell Creek Range, 14 miles (22.5 km.) northeast of Ely,. "White Pine County, Nev. (F. B. Weeks, 1900). Obolus rotundatus?. 8q. Lower Cambrian: Shales near the contact between the Cambrian and the Triassic, 2 miles (3.2 km.) northwest of York, York County, Pa. (A. Wanner, 1900). Obolus sp. . . OlenelluB thompsoni rudis Walcott. 8r. Upper Cambrian: Shales of the Emigrant formation [Turner, 1902, p. 265], about 8 miles (12.8 km.) south- east of Emigrant Peak, Silver Peak quadrangle (U. S. G. S.), Esmeralda County, Nev. (H. W. Turner). Obolus mcconnelli decipiens. 8v. (For stratigraphic position and association, see p. 146.) Lower Cambrian: Shales in upper portion of Eolmia hjerulfi zone, Ringsaker, near Lake Mjosen, Province of Hedemarken, Norway (Schmalensee, 1900). Obolella mobergi. * Acrothele bellapunctata. LOCALITIES. 173 8w (see 310 1, 320f, and 321y). (For stratigraphic position and association, see p. 145.) Middle Cambrian: Lime- stones of Paradoxides forchhammeri zone, at Andrarum, 20 miles (32 km.) northwest of Simrishamn, Province of Christianstad, Sweden (Schmalensee, 1900). Micromitra pusilla. Micromitra (Iphidella) ornatella. *Obolus schmalenseei. Lingulella ferruginea. Lingulella sp. Acrothele coriacea. Acrotreta sagittalis. *Aorotreta schmalenseei. Acrotreta socialis. Dolichometopus svecicus Angelin. Elyx laticeps Angelin. Solenopleura holometopa Angelin. 8x. (For stratigraphic position and association, see p. 144.) Passage beds between the Upper Cambrian and the Ordovician: Ciratopyge limestone at the cement works at Slenmiestad, in Rokea, about 3 miles (4.8 km.) southwest of Christiania, Norway (Schmalensee, 1900). Obolus (Broggeria) salteri. Lingulella lepis. Lingulella sp. Acrothele coriacea. *Acrotreta seebachi. Acrotreta socialis. Eoorthis daimus. Eoorthis wimani. Ceratopyge forficula Sars. Triarthrus angelini Linnarsson. 8y. (For stratigraphic position and association, see p. 146.) Lower Cambrian: With Torellella Ixvigata in the "Sparagmite" sandstone, at Sk&rosen, northwest Dalarne, Province of Kopparberg, Sweden (Schmalensee, 1900). Lingulella nathorsti. Torellella laevigata Linnarsson. 8z. (For stratigraphic position and association, see p. 146.) Middle Cambrian: Limestones of Paradoxides celandicus zone, Borgholm, Oeland Island, Sweden (Schmalensee, 1900). Liostracus aculeatus Angelin. Ellipsocephalus polytomus Linnarsson. Acrothele (Redlichella) granulata. Acrotreta socialis. Acrotreta sp. 9 (same horizon as 9a). (For stratigraphic position and association, see p. 147.) Middle Cambrian: Limestone on southeastern slope of ridge 1 mile (1.6 km.) north of the northwest corner of Harlan Knob, about 4 miles (6.4 km.) northeast of Rogersville [see Keith, 1905, areal geology sheet], Hawkins County, Tenn. (C. D. Walcott, 1891). Lingulella desiderata. 9a (same horizon as 9). (For stratigraphic position and association, see p. 147.) Middle Cambrian: Limestone on the south shore of Holston River, at Melinda Ferrj-, 5 miles (8 km.) southwest of Rogersville [see Keith, 1896a, areal geology sheet], Hawkins County, Tenn. (C. D. Walcott, 1891). Lingulella desiderata. Lingulella similis. 9d. (For stratigraphic position and association, see p. 143.) Upper Cambrian: Obolus sandstone at Jaggowal, about 20 miles (32.2 km.) east-southeast of Reval, Government of Esthonia, Ri^ssia (Schmalensee, 1900). Obolus apollinis. Obolus triangularis. Keyserlingia buchi. 9e. (For stratigraphic position and association, seep. 145.) Upper Cambrian: Sandstone in tho Obolus con- glomerate at Boda, north of Rattvik, Dalarne, Sweden (Schmalensee, 1900). Obolus apollinis. Si. (For stratigraphic position and association, see p. 145.) Upper Cambrian: Limestones of the Olenus zone at NcErsnaes, west of Christiania, Norway (Schmalensee, 1900). Lingulella lepis. Orusia lenticularis. Peltura scarabseoides Wahlenberg. 91i (limestone above the Wolsey shale). Middle Cambrian: Limestone on Beaver Creek, 5 miles (8 km.) north of York, about 8 miles (12.8 km.) north of Canon Ferry, Big Belt Mountains, Fort Logan quadrangle (U. S. G. S.), Meagher County, Mont. (C. D. Walcott, 1900). Micromitra pealei. I Acrotreta attenuata. Obolella?. | Billingsella plicatella. 9k. Middle Cambrian: Limestone forming Ic of the Dearborn River section [Walcott, 1908f, p. 201], on North Pork of Dearborn River, in the eastern part of the Lewis and Clark National Forest, Lewis and Clark County, Mont. (C. D. Walcott, 1900). *Dearbornia clarki. 174 CAJMBRIAN BRACHIOPODA. 9m. Middle Cambrian: Shale 4 miles (6.4 km.) above Walker's ranch, on North Fork of Dearborn River, in the eastern part of the Lewis and Clark National Forest, Lewis and Clark County Mont. (C. D. Walcott, 1900). Obolus (Westonia) ella. 9n (=3'26e). Lower Cambrian: Dark purplish siliceous shales on Pearl Street, North Weymouth, Norfolk County, Mass. (H. T. Burr, 1900). Obolella atlantica. Callavia burri Walcott. Callavia crosbyi Walcott. So. Middle Cambrian: Siliceous limestone about 15 feet (4.6 m.) above the Coronado quartzite [Lindgren, 1905, p. 3], 0.5 mile (0.8 km.) southwest of Milk ranch, on the first spur north of the one which the main road follows, Clifton quadrangle (U. S. G. S.), Graham County, Ariz. (J. M. Boutwell, 1901). Lingulella lineolata. Lingulella perattenuata. 9p (about 115 feet above 9r; 55 feet above 12s; almost same horizon as 9x; 10 feet below 9t). (For stratigraphic position and association, see p. 142.) Upper Cambrian: About 160 feet (48.8 m.) above the porphyry con- tact in the limestone of the Reagan sandstone, in SE. J NE. J sec. 2, T. 4 N., E.. 13 W., about 15 miles (24.2 km.) northwest of Fort Sill, Comanche County, Okla. (E. 0. Ulrich, 1901). Obolus tetonensis ninus. *Lingulella ora. Linnarssonella girtyi. Ptychoparia sp. Chariocephalus sp. Illsenurus sp. 9q (50 feet below 12d). (For stratigraphic position and association, see p. 142.) Upper Cambrian: About 10 feet (3 m.) above the porphyry contact and 90 feet (27.4 m.) below the Arbuckle limestone, in limestone o'f the Reagan sandstone, in middle of west half of sec. 2, T. 4 N., R. 13 W., about 15 miles (24.2 km.) northwest of Fort Sill, Comanche County, Okla. (E. 0. UMch, 1901). Obolus tetonensis ninus. Lingulella ora. Lingulella (Lingulepis) acuminata. Linnarssonella girtyi. Linnarssonella girtyi?. Eoorthis wichitaensis. Agnostus sp. Agraulos sp. Ptychoparia sp. Pterocephalus sp. 9r (about 125 feet below 9t; about 115 feet below 9p; see 9v). (For stratigraphic position and association, see p. 142.) Upper Cambrian: About 45 feet (14 m.) above the porphyry contact in the limestone of the Reagan sandstone, in SE. J NE. } sec. 2, T. 4 N., R. 13 W., 15 miles (24.2 km.) northwest of Fort Sill, Comanche County, Okla. (E. 0. Ulrich, 1901). Acrotreta microscopica. Agnostus sp. Ptychoparia sp. *Obolus tetonensis ninus. Lingulella similis. Linnarssonella girtyi. 9s (believed to just overlie 9u). (For stratigraphic position and association, see p. 142.) Upper Cambrian: About 85 feet (26 m.) below the Arbuckle limestone, in the limestone of the Reagan sandstone, near middle of west half of sec. 13, T. 4 N., R. 13 W., 13 miles (20.8 km.) northwest of Fort Sill, Comanche County, Okla. (E. O. Ulrich, 1901). Obolus tetonensis ninus. I Lingulella (Lingulepis) acuminata. Lingulella similis. |. Eoorthis wichitaensis. 9t (125 feet above 9r; 10 feet above 9p; 25 feet below 9u; see 9v). (For stratigraphic position and association, see p. 142.) Upper Cambrian: About 170 feet (52 m.) above the porphyry contact in the limestone of the Reagan sandstone, SE. J NE.J sec. 2, T. 4 N., R. 13 W., 15 miles (24.2 km.) northwest of Fort Sill, Comanche County, Okla. (E. 0. Ulrich, 1901). Acrotreta microscopica. Eoorthis indianola. Ptychoparia sp. Obolus matinalis. Obolus tetonensis ninus. Lingulella similis. 9u (believed to just underlie 9s; 25 feet above 9t). (For stratigraphic position and association, see p. 142.) Upper Cambrian: About 195 feet (59.4 m.) above the porphyry contact in the limestone of the Reagan sandstone, in SE. } NE. i sec. 2, T. 4 N., R. 13 W., 15 miles (24.2 km.) northwest of Fort Sill, Comanche County, Okla. (E. 0. Ulrich, 1901). Obolus tetonensis ninus. Lingulella similis. Eoorthis indianola. Eoorthis wichitaensis. Syntrophia primordialis. Agnostus sp. Ptychoparia sp. LOCALITIES. 175 9v (150 feet below 9w; between 9r and 9t). (For stratigraphic position and association, see p. 142.) Upper Cam- brian: Limestone of the Reagan sandstone about 250 feet (76 m.) below the Arbuckle limestone, SW. J sec. 17, T. 4 N., R. 12 W., about 11 miles (17.7 km.) northwest of Fort Sill, Comanche County, Okla. (E. 0. Ulrich, 1901). Lingulella (Lingulepis) acuminata. Linnarssonella girtyi. Agnostus sp. Agraulos sp. Chariocephalus? sp. Illaenurus? sp. 9w (150 feet above 9v). (For stratigraphic position and association, see p. 142.) Upper Cambrian: Limestone of the Reagan sandstone about 100 feet (30.5 m.) below the Arbuckle limestone, SW. J sec. 17, T. 4 N., R. 12 W., 11 miles (17.7 km.) northwest of Fort Sill, Comanche County, Okla. (E. 0. Ulrich, 1901). Eoorthis indianola. Agnostus. 9x (almost same horizon as 9p). (For stratigraphic position and association, see p. 142.) Upper Cambrian: Sand- stones lying between beds of quartzite underlying the 300 feet of limestone at the top of the Reagan sand- stone, SW. i sec. 17, T. 4 N., R. 12 W., about 11 miles (17.7 km.) northwest of Fort Sill, Comanche County, Okla. (E. O. Uh-ich, 1901). Dicellomus politus. 9z. (For stratigraphic position and association, see p. 142.) Upper Cambrian: Basal beds of the Arbuckle lime- stone, about 25 feet above the heavy bedded limestone, near the middle of the west half of sec. 13, T. 4 N., R. 13 W., about 13 miles (20.8 km.) northwest of Fort Sill, Comanche County, Okla. (E. 0. Ulrich, 1901). Eoorthis wichitaensis. Dikellocephalus. 10a (see 106). (For stratigraphic position and association, see p. 147.) Middle Cambrian: Sandy layers of the Rome formation in western railroad cut through Shooks Gap, in Bays Mountains, 10 miles (16.1 km.) south- east of Knoxville [see Keith, 1895, areal geology sheet], Knox County, Tenn. (C. D. Walcott, 1891). *Obolus pandemia. *Lingulella auga. Lingulella similis. lOb. (For stratigraphic position and association, see p. 147.) Middle Cambrian: Sandy layers of the Rome forma- tion at the western end of the central railroad cut through Shooks Gap, in Bays Mountains, 10 miles (16.1 km.) southeast of Knoxville [see Keith, 1895, areal geology sheet], EJiox County, Tenn. (C. D. Walcott, 1891). Lingulella auga. 10c (50 feet below 10k). (For stratigraphic position and association, see p. 131.) Upper Cambrian: Shales on west side of Barachois River, eastern Cape Breton, Nova Scotia (S. W. Loper, 1901). Obolus (Broggeria) salteri. I Schizambon priscus?. Lingulella concinna. . | Acrotreta bisecta. lOd. (For stratigraphic position and association, seep. 131.) Upper Cambrian: Shales on west side of Barachois River, 0.125 mUe (0.2 km.) north of Boisdale road, opposite McMullin's place, eastern Cape Breton, Nova Scotia (S. W. Loper, 1901). Obolus (Broggeria) salteri. Lingulella concinna. Schizambon priscus. Acrotreta bisecta. lOe (50 feet above lOf). (For stratigraphic position and association, see p. 131.) Upper Cambrian: Shales on the east branch of Barachois River, 0.5 mile (0.8 km.) north of the crossroad from Boisdale to Upper Leitches Creek, eastern Cape Breton, Nova Scotia (S. W. Loper, 1901). Obolus (Broggeria) salteri. Lingulella concinna. Schizambon priscus. Acrotreta bisecta. Acrotreta convexa. lOf (=10g; 59 feet below lOe). (For stratigraphic position and association, see p. 131.) Upper Cambrian: Shales on the east branch of Barachois River, 0.75 mile (1.2 km.) north of the crossroad from Boisdale to Upper Leitches Creek, eastern Cape Breton, Nova Scotia (S. W. Loper, 1901). Obolus (Broggeria) salteri. Lingulella concinna. Schizambon priscus. Acrothele sp. Acrotreta bisecta. lOg (=10f). (For .stratigraphic position and association, see p. 131.) (S. W. Loper, 1901 Obolus (Broggeria) salteri Lingulella concinna. Schizambon priscus. Acrotreta bisecta. Acrothyra proavia. 176 CAMBRIAN BEACHIOPODA. lOh. (For stratigraphic position and association, see p. 131.) Upper Cambrian : Shale on small east branch of Bara- chois River, 0.75 mile (1.2 km.) north of the crossroad from Boisdale to Upper Leitches Creek, eastern Cape Breton, Nova Scotia (S. W. Loper, 1901). Lingulella concinna. I Acrotreta bisecta. Schizambon priscus. | Orusia lenticularis. lOi. (For stratigraphic position and association, see p. 131.) Upper Cambrian : Shale in high bank on west side of Barachois River, just north of the Boisdale road, eastern Cape Breton, Nova Scotia (S. W. Loper, 1901). Obolus (Broggeria) salteri. I Schizambon priscus. Lingulella concinna. I Acrotreta convexa. 10k (50 feet above 10c). (For stratigraphic position and association, see p. 131.) Upper Cambrian : Shale on west bank of Barachois River, about 0,25 mile (0.4 km.) north of the Boisdale road, eastern Cape Breton, Nova Scotia (S. W. Loper, 1901). Schizambon priscus. lOL (For stratigraphic position and association, see p. 131.) Upper Cambrian: Shale on east bank of Barachois River, 6 miles (9.6 km.) from Little Bras d'Or Lake, eastern Cape Breton, Nova Scotia (S. W. Loper, 1901). Obolus (Broggeria) salteri. Lingulella concinna. Schizambon priscus. Acrotreta bisecta. Acrotreta convexa. 10m (see 372a). (For stratigraphic position and association, see p. 131.) Upper Cambrian: Shales 2 miles (3.2 km.) south of the Boisdale road from Upper Leitches Creek, toward the head of Barachois River, eastern Cape Breton, Nova Scotia (S. W. Loper, 1901). Obolus (Broggeria) salteri. Lingulella concinna. lOn. (For stratigraphic position and association, see p. 131.) Ifpper Cambrian: Shale in ravine on east side of Barachois Glen, 3 miles (4.8 km.) from Barachois, eastern Cape Breton, Nova Scotia (S. W. Loper, 1901). Obolus (Broggeria) salteri. Lingulella concinna. Acrotreta bisecta. lOo. (For stratigraphic position and association, see p. 132.) Middle? Cambrian: Arenaceous shales in the railroad cut on the shore of Bras d'Or Lake, at Barachois, eastern Cape Breton, Nova Scotia (S. W. Loper, 1901). Obolus (Westonia) escasoni?. lOp (a little below lOq; see 344o). (For stratigraphic position and association, see p. 134.) Middle Cambrian: Sandstone just below the waterfall in Division E2b of Matthew's [1903, p. 21] Etcheminian, Dugald Brook, Indian River, eastern Cape Breton, Nova Scotia (S. W. Loper, 1901). Obolus (Palseobolus) bretonensis. Lingulella atava. Lingulella collicia. Lingulella triparilis. Lingulella sp. Lingulella (Lingulepis) gregwa. Lingulella (Lingulepis) gregwa robusta. Lingulella (Lingulepis) longinervis. Acrothele avia. Acrotreta gemmula. Acrothyra proavia. Acrothyra sera. Acrothyra signata. Acrothyra signata orta. *Protorthis (Loperia) dugaldensia. Matthew [1903, p. 25] gives the following as occurring in Division 2b: Acrothyra signata tarda=Acrothyra sera. I Orthotheca. Lingulepis longinervis. | Bradorona perspicator magna Matthew. Bassler cites the following from this locality: Bradoria acuta (Matthew). Bradoria benepuncta (Matthew). Bradoria ovalis (Matthew). Bradoria perspicator (Matthew) ss. Bradoria robusta (Matthew). Bradoria spectator (Matthew). lOp'. (For stratigraphic position and association, see p. 134.) Middle Cambrian; Sandstone 0.25 mile (0.4 km.) from lower bridge, on Gregwa Brook, Indian River, eastern Cape Breton, Nova Scotia (S. W. Loper, 1901). Lingulella (Lingulepis) gregwa. I Lingulella (Lingulepis) longinervis. Lingulella (Lingulepis) gregwa robusta. | Acrothyra sera. LOCAI.ITIES. 177 lOp". (For stratigraphic position and association, see p. 134.) Middle Cambrian: Sandstone on the small brook on the hill between the bridge over Indian River and McPhees Brook, Cape Breton, Nova Scotia (S. W. Loper, 1901). Obolus (Palseobolus) bretonensis. Lingulella (Lingulepis) gregwa. Lingulella (Lingulepis) gregwa robusta. Lingulella (Lingulepis) longinervis. Acrothele a^da. Acrotreta gemmula. Acrothyra sera. Bradoria robusta (Matthew). Bradoria obesa (Matthew). lOq (a little above lOp; see 344o). (For stratigraphic position and association, see p. 134.) Middle Cambrian: Sandstone below the waterfall in Division E2b of Matthew's [1903, p. 21] Etcheminian, Dugald Brook, Indian River, eastern Cape Breton, Nova Scotia (S. W. Loper, 1901). Acrothyra proa^da. Matthew [1903, p. 25] cites the following species from Division 2b: Acrothyra signata tarda=Acrothyra sera. j Orthotheca. Lingulepis longinervis. I Bradorona perspicator magna Matthew. Bassler cites the following from this locality: Bradoria elongata n. sp. lOr. (For stratigraphic position and association, see p. 131.) Upper Cambrian: Arenaceous shales of Division C3a? of Matthew at McAdam shore, East Bay, east of Bras d'Or Lake, eastern Cape Breton, Nova Scotia (S. W. Loper, 1901). Obolus (Broggeria) salteri. I Obolus (Westonia) escasoni?. Obolus (Palseobolus) bretonensis. | *Lingulella lens. 10s. (For stratigraphic position and association, see p. 132.) Middle Cambrian: Sandstone on McLean Brook, near Marion Bridge, eastern Cape Breton, Nova Scotia (S. W. Loper, 1901). Lingulella cania. Lingulella (Lingulepis) exigua. Beyrichona triceps Matthew. lot. (For stratigraphic position and association, see p. 132.) Middle Cambrian: Sandstone on McLean Brootc, near Marion Bridge, eastern Cape Breton, Nova Scotia (S. W. Loper, 1901). Lingulella (Lingulepis) exigua. " lOv. LTpper Cambrian : Shales in the "St. Croix sandstone " at Fox Glen, about 8 miles (12.8 km.) east of Baraboo, Baraboo quadrangle (U. S. G. S.), Sauk County, Wis. *Obolus pheres. Lingulella winona. *Acrotreta nox. lOw. (For stratigraphic position and association, see p. 139.) Middle Cambrian: Shaly limestones about 5 miles (8 km.) northeast of Osceola, on the east side of the Snake Range, White Pine County, Nev. (C. D. Walcott, 1903). Micromitra sculptilis. Obolus mcconnelli. lOy (same horizon as lOz). (For stratigraphic position and association, see p. 155.) Middle Cambrian: About 2,900 feet (884 m.) above the Lower Cambrian and 1,500 feet (457.2 m.) below the Upper Cambrian, in the central part of the limestone forming la of the Marjum limestone [Walcott, 1908f, p. 179], about 1 mile (1.6 km.) south-southwest of Marjum Pass, House Range [Walcott, 1908f, PI. XIII], Millard Comity, Utah (C. D. Walcott and F. B. Weeks, 1903). Micromitra sculptUis. Obolus mcconnelli. Lingulella arguta. Acrothele subsidua. Acrotreta attenuata. Agnostus. Ptychoparia. Anomocare. lOz (same horizon as lOy). (For stratigraphic position and association, seep. 155.) Middle Cambrian: About 2,900 feet (884 m.) above the Lower Cambrian and 1,500 feet (457.2 m.) below the Upper Cambrian, in the central part of the limestone forming la of the Marjum limestone [^'alcott, 1908f, p. 179], in the long cliff about 2 miles (3.2 km.) southeast of Marjum Pass [see Walcott, 1908f, Pis. XIII and XV], House Range, Millard County, Utah (C. D. Walcott, F. B. Weeks, and L. D. Burling, 1903 and 1905). *Dicellomus proliiicus. *Acrotreta bellatula. Agnostus 2 sp. 62667°— VOL 51, pt 1—12 12 Ptychoparia 2 sp. Agraulos. Anomocare. 178 ■ CAJMBRIAN BRACHIOPODA. 11. (For stratigraphic position and association, see p. 147.) Middle Cambrian: Sandstones and shales of the Kome formation, about 1 mile (1.6 km.) east of Post Oak Springs [see Hayes, 1894, areal geology sheet], Roane County, Tenn. (C. D. Walcott, 1891). Lingulella ino. *Lingulella tarpa. 11a. (For stratigraphic position and association, see p. 147.) Middle Cambrian: Sandstone between First and Armstrong creeks, in the southeast corner of the Maynardville quadrangle (U. S. G. S.), Union County, Tenn. (c! D. Walcott, 1891). Obolus sinoe. Lingulella tarpa. Dicellomus appalachia. lie. Upper Cambrian: Hardyston quartzite [W^eller, 1900, pp. 110 and 112], O'Donnell and McManniman's quarry, Newton, Sussex County, N. J. (H. E. Dickhaut, 1901). *Liiigulella welleri. Weller [1900, p. 12] cites the following from this locality: Ptychoparia newtonensis Weller. Ptychoparia 2 sp. undt. Anomocare parvula Weller. Dikellocephalus newtonensis Weller. Foraminifera?. Lingulella stoneana=Obolus (Westonia) stoneanus. *Orthis newtonensis=Eoorthis newtonensis. Microdiscus? sp. Olenellus ? sp. lid. (For stratigraphic position and association, see p. 137). Upper Cambrian: Arenaceous limestone about 2 miles (3.2 km.) north of Montana, in sec. 22, T. 35 N., R. 1 E., Iron County, Mo. (D. K. Greger). Obolus matinalis ?. Billingsella coloradoensis. Eoorthis remnicha texana?. lie. (For stratigraphic position and association, see p. 137.) Middle Cambrian: In thin-bedded limestones south- southwest of Potosi, Washington County, Mo. (D. K. Greger). Obolus matinalis ?. Lingulella similis. Lingulella sp. Linnarssonella girtyi. Acrotreta microscopica missouriensis. Billingsella coloradoensis. llj. (For stratigraphic position and association, see p. 137.) Middle Cambrian: Basal part of Bonneterre lime- stone, Mine Lamotte, Madison County, Mo. (E. O. Ulrich, 1904). *Obolus lambomi. | Lingulella acutangula. Obolus sinoe. I Dicellomus nanus. Ilk. (For stratigraphic position and association, see p. 137.) Middle Cambrian: In sandstones and limestones of the " Edgewise beds, " St. Francois County, Mo. (F. Nason, 1901). Lingulella acutangula. Linnarssonella girtyi. *Acrotreta microscopica missouriensis. 111. (For stratigraphic position and association, see p. 137.) Upper Cambrian: Arenaceous limestone of the Elvins formation, 50 feet (15.2 m.) above the " Edgewise beds, " St. Francois County, Mo. (F. Nason, 1901). Lingulella acutangula ?. Billingsella coloradoensis. ... Eoorthis remnicha texana ?. 11m. (For stratigraphic position and association, see p. 137.) Middle Cambrian: Drill cores of limestone in the Bonneterre limestone, at horizons 10 and 20 feet (3 and 6 m.) above the Lamotte sandstone, at Flat River, St. Francois County, Mo. (F. Nason, 1901). Micromitra sp. Micromitra (Paterina) cf. stissingensis. Obolus lambomi. Lingulella cf. ora. Dicellomus nanus. Dicellomus. politus. lln. (For stratigraphic position and association, see p. 155.) Middle Cambrian: About3,000 feet (914.4 m.) above the Lower Cambrian and 1,400 feet (426.7 m.) below the Upper Cambrian, in the upper part of the lime- stone forming la of the Marjum limestone [Walcott, 1908f, p. 179], in the long cliff 2 miles (3.2 km.) south- east of Marjum Pass [see Walcott, 1908f, Pis. XIII and XV], House Range, MiUard County, Utah (C. D. Walcott, F. B. Weeks, and L. D. Burling, 1903 and 1905). Obolus mcconnelli pelias. *Obolus (Fordinia) gilberti. Acrotreta bellatula. *Acrotreta marjiimensis. *Acrotreta cf . sagittalis. Agnostus 4 sp. ■: ;• t - LOCALITIES. * 179 llo. (For stratigrapMc position and association, see p. 155.) Middle Cambrian: About 2,750 feet (838.2 m.) above the Lower Cambrian and 1,650 feet (502.9 m.) below the Upper Cambrian, in limestone at the base, la, of the Marjum limestone [Walcott, 1908f, p. 179], about 4 miles (6.4 km.) southeast of Antelope Springs, in the spur at the junction of the Deseret and Swasey Spring roads [Walcott, 1908f, PL XIII], House Range, Millard County, Utah (C. D. Walcott, F. B. Weeks, and L. D. Burling, 1903 and 1905). Stenotheca sp. Hyolithes. Bathyuriscus?. Ptychoparia 2 sp. Anomocare. Micromitra (Iphidella) pannula ophirensis Obolus mcconnelli pelias. Obolus rotundatus. Acrotreta idahoensis. Annelid trails. lip. (For stratigraphic position and association, see p. 156.) Middle Cambrian: About 2,000 feet (609.6 m.) above the Lower Cambrian and 2,400 feet (731.5 m.) below the Upper Cambrian, iu the limestones forming le of the Marjum limestone [^'alcott, 1908f, p. 181], in the long cliff about 2.5 miles (4 km.) southeast of Mar- jum Pass [Walcott, 1908f, Pis. XIII and XV], House Range, Millard County, Utah (C. D. Walcott, F. B. Weeks, and L. D. Burling, 1905). Linnarssonella sp. Sponge spiculse. Agnostus, several sp. ■? Ogygopsis Ptychoparia 2 sp. llq (=lly and 30g; same horizon as 3w). (For stratigraphic position and association, see p. 156.) (C. D. Walcott, F. B. Weeks, and L. D. Burling, 1903 and 1905.) Neolenus inflatus Walcott. Neolenus intermedius Walcott. Neolenus intermedius pugio Walcott. Neolenus superb us Walcott. Ogygopsis?. *Obolus mcconnelli pelias. Lingulella arguta. Acrothele subsidua. Nisusia (Jamesella) nautes?. Nisusia (Jamesella) spencei. Boorthis thyone. lis. (For stratigraphic position and association, see p. 157 . ) Middle Cambrian : Shales just above Simpson Spring, about 20 miles (32.2 km.) west-southwest of Verhon, on the stage road from Vernon to Fish Spring, Tooele County, Utah (C. D. Walcott, 1903). Obolus (Westonia) ella?. Micromitra sculptilis. llu. (For stratigraphic position and association, see p. 156.) Middle Cambrian: Lower portion of the shales forming the Wheeler formation, in Rainbow Valley, House Range [see Walcott, 1908f, PI. XIII], Millard County, Utah (C. D. Walcott, 1903). Acrothele subsidua. llw (=30c). (For StratigrapMc position and association, see p. 157.) Middle Cambrian: About 1,050 feet (320 m.) above -the Lower Cambrian and 3,350 feet (1,021.1 m.) below the Upper Cambrian, iu the shales forming Id of the Swasey formation fW^alcott, 1908f, p. 182], at the head of Dome Canyon, House Range [Walcott, 1908f, PL XIII], Millard County, Utah (C. D. Walcott and F. B. Weeks, 1903). Lingulella arguta. Ptychoparia. llx (=3x). (For stratigraphic position and association, see p. 156.) (C. D. Walcott, 1903.) Obolus rotundatus. Lingulella arguta. lly (=llq and 30g). (For stratigraphic position and association, see p. 156.) (C. D. Walcott, 1903.) Lingulella arguta. Acrothele subsidua. Acrotreta cf. ophirensis. llz. (For stratigraphic position and association, see p. 132.) Middle Cambrian: Sandstone on Big Ridge 2 miles (3.2 km.) south of Marion Bridge, on the canal of John McDougald, eastern Cape Breton, Nova Scotia (S. W. Loper). Obolus (Westonia) escasoni. Lingulella (Lingulepis) exigua. 12. (For stratigraphic position and association, see p. 147.) Middle Cambrian: Sandy shale on Webbs Ridge, in gap west of Simpson's farm, 6 miles (9.6 km.) northeast of Knoxville, Knox County, Tenn. (C. D. Walcott, 1891). Linnarssonella tennesseensis. •• 180 CAMBRIAN BRACHIOPODA. 12j (50 feet below 12g; 40 feet above 12i). (For stratigraphic position and association, see p. 142.) Upper Cam- brian: Lower part of Arbuckle limestone, second fossiliferous horizon in the section at Small Hill, 2 miles (3.2 km.) southwest of Signal Mountain, about 8 miles (12.8 km.) west of Fort Sill, Comanche County, Okla. (E. O. Ulrich, 1901). Eoorthis wichitaensis. Agraulos sp. DikellocephaUis sp. Ptychaspis sp. Illsenuius sp. 12k (15 feet below 12n in Springer section). (For stratigraphic position and association, see p. 142.) Upper Cam- brian: Limestone of the Reagan sandstone, about 225 "feet (69 m.) above the porphyry contact and 55 feet (17 m.) below the Arbuckle limestone, on the west side of Honey Creek, near southeast corner sec. 35, T. 1 S., R. 1 E., 7 miles (11.2 km.) north of Springer, Ardmdre quadrangle (U. S. G. S.), Carter County, Okla. (E. 0. Ulrich, 1901). Obolus tetonensis ninus. Lingulella simihs. Acrotreta microscopica. *Eoorthis indianola. Eoorthis remnicha. Eoorthis wichitaensis. Eoorthis wichitaensis Iseviusculus. Chariocephalus sp. 12m. (For stratigraphic position and association, see p. 142.) Upper Cambrian: Arbuckle limestone [in the section 7 miles (11.2 km.) north of Springer this horizon is about 30 feet (9.1 m.) above the Reagan sandstone], NE. i sec. 2, T. 2 S., R. 1 E., Ardmore quadrangle (U. S. G. S.), Carter County, Okla. (E. O. Ulrich, 1901). Obolus tetonensis ninus. Lingulella similis. Eoorthis remnicha texana. Agraulos sp. Ptychaspis sp. 12n (15 feet above 12k in Springer section). (For stratigraphic position and association, see p. 142.) Upper Cam- brian: Limestone of the Reagan sandstone about 240 feet (73 m.) above the porphyry contact and 40 feet (12 m.) below the Arbuckle limestone, NW. J sec. 1, T. 2 S., R. 1 E., 7 miles (11.2 km.) north of Springer, Ardmore quadrangle (U. S. G. S.), Carter County, Okla. (E. 0. Ulrich, 1901). Obolus tetonensis ninus. Lingulella similis. Lingulella (Lingulepis) acuminata. Acrotreta microscopica. Eoorthis indianola. Eoorthis remnicha. Eoorthis remnicha texana. Eoorthis wichitaensis. Eoorthis wichitaensis Iseviusculus. Syntrophia primordialis. Ptychoparia sp. Chariocephalus sp. 12p. (For stratigraphic position and association, see p. 142.) Upper Cambrian: About 225 feet (69 m.) above the igneous rocks in the limestone of the Reagan sandstone, at the northwest extremity of the Arbuckle Mountains, about 4 miles (6.4 km.) east of Homer, Carter County, Okla. Obolus tetonensis ninus. Lingulella similis. Lingulella (Lingulepis) acuminata. Acrotreta curvata. Acrotreta microscopica. ^Acrotreta ulrichi. Linnarssonella girtyi. Eoorthis indianola. Eoorthis remnicha. *Eoorthis wichitaensis. *Boorthis wichitaensis Iseviusculus. Agraulos sp. Ptychoparia sp. Chariocephalus sp. Illsenurus sd. 12ci. (For stratigraphic position and association, see p. 147.) Upper Cambrian: Knox dolomite on Bunker Hill, 6 miles (9.6 km.) northeast of Rogersville [see Keith, 1905, areal geology sheet], Hawkins County, Tenn. (M. R. Campbell, 1892). *Syntrophia campbelli. 12v. Lower Cambrian: Sandstone above the quartzite 1 mile (1.6 km.) west of Fruitville, on Little Conestoga Creek, Manheim Township, Lancaster County, Pa. (C. D. Walcott, 1909). Obolella crassa? 13. (For stratigraphic position and association, see p. 147.) Middle Cambrian : Sandstones of the Rome formation 1.5 miles (2.4 km.) east of Post Oak Springs [see Hayes, 1894, areal geology sheet], Roane County, Tenn. (C. D. Walcott, 1891). Lingulella ino. '^Linnarssonella tennesseensis. 13b. (For stratigraphic position and association, seep. 147.) Middle Cambrian: Sandstones of the Rome formation northeast of Rhea Springs [see Hayes, 1894, areal geology sheet], Roane County, Tenn. (C. D. Walcott, 1891). Micromitra (Paterina) crenistria. ■'Lingulella ino. LOCALITIES. 181 13c. (For stratigraphic position and association, see p. 147.) Middle Cambrian; Sandstones of the Rome formation, west side of the sandstone ridge about 2.5 miles (4 km.) southwest of Rome [see Hayes, 1902, historical geology sheet], Floyd County, Ga. (C. D. Walcott, 1891). Lingulella ino. 13d (=13d'). (For stratigraphic position and association, see p. 134.) Middle Cambrian: Sandstones opposite the third waterfall in Dugald Brook, between Divisions E2a and E2b of Matthew's [1903, p. 21] Etcheminian, Dugald Brook, Indian River, eastern Cape Breton, Nova Scotia (S. W. Loper, 1903). Lingulella (Lingulepis) longinervis. Acrothele a via. Bradoria robusta (Matthew). 13d' (=13d). (For stratigraphic position and association, see p. 134.) (S. W. Loper, 1903.) Obolus (Palseobolus) bretonensis. Acrothele avia. Lingulella atava. Acrothyra sera. Lingulella collicia. Acrothyra signata. 13d" (see 13p, ISg, 13f, and 13p'). (For stratigraphic position and association, see p. 134.) Middle Cambrian: Sandstones 10 feet (3 m.) below Division E2a of Matthew's [1903, p. 21] Etcheminian, Dugald Brook, Indian River, eastern Cape Breton, Nova Scotia (S. W. Loper, 1903). Lingulella (Lingulepis) longinervis. I Acrothele prima. Acrothele avia. | Acrothyra signata orta. Bassler cites the following from this locality: Bradoria benepuncta (Matthew). J Bradoria robusta (Matthew). Bradoria perspicator (Matthew) (ss). ] Bradoria rugulosa Matthew (emend.). 13e (see 3441). (For stratigraphic position and association, see p. 134.) Middle Cambrian: Sandstones o' Divi- sion E2c of Matthew's [1903, p. 21] Etcheminian, Dugald Brook, Indian River, eastern Cape Breton, Nova Scotia (S. W. Loper, 1903). Obolus (Palseobolus) bretonensis lens. Acrothyra proavia. Acrothyra sera. Matthew [1903, p. 25] gives the following fauna occurring in 2c: Acrothyra signata orta. Bradorona observator Isevis Matthew. 13f (see 13p, 13g, 13d", and 13p'). (For stratigraphic position and association, see p. 134.) Middle Cambrian: Sandstones 20 feet (6 m.) above Division E2a of Matthew's [1903, p. 21] Etcheminian, Dugald Brook, Indian River, eastern Cape Breton, Nova Scotia (S. W. Loper, 1903). Lingulella (Lingulepis) longinervis. Acrothyra sera. 13g (see 13p, 13f, 13d", and 13p'). (For stratigraphic position and association, see p. 134.) Middle Cambrian: Sandstones 10 feet (3 m.) above Division E2a of Matthew's [1903, p. 21] Etcheminian, Dugald Brook, India.n River, eastern Cape Breton, Nova Scotia (S. W. Loper, 1903'). Lingulella (Lingulepis) longinervis. Bassler cites the following species from this locality: Hymenocaris? matthewi n. sp. ISh. (For stratigraphic position and association, see p. 131.) Upper Cambrian: Shale on east bank of Barachois River, 1.5 miles (2.4 km.) north of Boisdale, eastern Cape Breton, Nova Scotia (S. W. Loper, 1903). Obolus (Broggeria) salteri. • I Schizambon priscus. Lingulella concinna. | Acrotreta bisecta. 13i (little different horizon than 13r). (For stratigraphic position and association, see p. 132.) Middle Cambrian: Sandstone of the " Johannian" Division of Matthew's section, on Gillis Brook, East Bay, east of Bras d'Or Lake, eastern Cape Breton, Nova Scotia (S. W. Loper, 1903). Lingulella tumida. 13k (see 344f). (For stratigraphic position and association, see p. 135.) Middle Cambrian: Shales of Matthew's [1903, p. 15] Coldbrook, above the great falls in Dugald Brook, Indian River, eastern Cape Breton, Nova Scotia (S. W. Loper, 1903). Acrothyra sera. *Acrothyra signata prima. Micromitra (Iphidella) pannula?. *Obolus? torrentis. Lingulella (Lingulepis?) pumila?. 131 (=13 F). (For stratigraphic position and association, see p. 133.) (S. W. Loper, 1903.) Obolus (Palseobolus) bretonensis lens. I Acrothele avia. Lingulella (Lingulepis) longinervis. | Acrothyra proavia. 182 CAIIBRIAN. BRACHIOPODA. Acrothele abavia. Acrothyra proavia (p. 57). *Acrotliyra proavia prima. 131' (=131; see 344i). (For stratigraphic position and association, see- p. 133.) Middle Cambrian: In the shaly sandstones of Division E3a of Matthew's [1903, p. 21] Btcheminian, Dugald Brook, Indian . River, eastern Cape Breton, Nova Scotia (S. W. Loper, 1903). , Obolus (Palasobolus) bretonensis. I Acrothele avia. Lingulella atava. | Acrothele proles. Matthew [1903] cites the following from this locality: Obolus lens (pp. 58, 80).- Obolus (Palseobolus) bretonensis (p. 26). Lingula sp. Leptobolus sp. Bassler cites the following from this locality: • Bradoria acuta (Matthew). , . , •,,(,.; Bradoria curta Bassler. 13m. (For stratigi-aphic position and association, see p. 133.) Middle Cambrian: Sandstones of Division E3f of Matthew's [1903, p. 76] Etcheminian, on Gillis Brook, Indian River, eastern Cape Breton, Nova Scotia (S. W. Loper, 1903). ■ Obolus (Palseobolus) bretonensis lens. I Acrothele avia. Lingulella collicia. | *Acrothele proles. Matthew [1903] cites the following: Leptobolus collicia=Lingulella collicia. Leptobolus collicia collis=Lingulella collicia. Acrothele avia puteis. Acrothele proles. Bassler cites the following from locality No. 13m": Bradoria acuta (Matthew). Bradoria vigilans Matthew. Beyrichona rutellum (Matthew). 13n (see 344d). (For stratigraphic position and association, see p. 133.) Middle Cambrian: Sandstones of Divi- sion E3f of Matthew's [1903, p. 21] Etcheminian, on Dugald Brook, Indian River, eastern Cape Breton, Nova Scotia (S. W. Loper, 1903). Lingulella atava. Acrothele avia. Acrothele proles. Acrothyra proavia crassa= Acrothyra proavia prima= Leperditia?? rugosa. Bradoi'ia scrutator. : Acrothyra proavia. : Acrothyra proavia. Acrothyra proavia prima?=Acrothyra proavia. Bradorona perspicator major. Bradorona scrutator. Solenopleura (?) bretonensis (part). Matthew [1903, p. 37] cites the following: Leptobolus atavus=Lingulella atava. Leptobolus collicia=Lingulella collicia. Leptobolus collicia collis=Lingulella collicia. Acrothele proles. Acrothyra crassa?=Acrothyra proavia. Bassler cites the following: Bradoria scrutator (Matthew). Indiana lippa (Matthew). Walcottella fusiformis (Matthew). 13n'. (For stratigraphic position and association, see p. 133.) Middle Cambrian: Sandstones of Division E3e of Matthew's [1903, p. 21] Etcheminian, Dugald Brook, Indian River, eastern Cape Breton, Nova Scotia (S. W. Loper, 1903). *Obolus (Palasobolus) bretonensis lens. *Lingulella atava. *Lingulella collicia. Matthew [1903, p. 27] cites the following: Obolus lens. Obolus lens longus. Lingulella tumida. Lingulella sp. Leptobolus atavus. Leptobolus collicia. Acrothele abavia. Acrothele avia. Acrothyra proavia. *Lingulella tumida. *Acrothele avia. Acrothyra proavia. Acrothyra proavia crassa. Indiana ovalis. Bradorona observator ligata. Bradorona scrutator. Bradoria rugulosa. Bradoria vigilans. Schmidtella? acuta. Schmidtella? pervetus. LOCALITIES. 183 Bradoria vigilans MattheT* , Bradoria ovalis Matthew. Bradoria acuta (Matthew). Bassler cites the following: Indiana lippa (Matthew). Bradoria robusta (Matthew). Bradoria rugulosa Matthew. Bradoria scrutator (Matthew). ISn" (see 344b). (For stratigraphic position and association, see p. 133.) Middle Cambrian: Sandstones of Division E3d of Matthew's [1903, p. 21] Etcheminian, Dugald Brook, Indian River, Cape Breton, Nova Scotia (S. W. Loper, 1903). Obolus (PalEeobolus) bretonensis. Lingulella atava. • Acrothyra proa via. Matthew [1903, Obolus bretonensis. Leptobolus atavus. p. 26] cites the following: I Acrothele avia. 1 Bradorona spectator sequat. Bradoria robusta (Matthew). Bradoria vigilans Matthew. Bassler cites the following: Bradoria acuta (Matthew). Bradoria elongata n. sp. Bradoria obesa (Matthew). 13p (see 13g, 13f, 13d", and 13p'). (For stratigraphic position and association, see p. 134.) Middle Cambrian: Sandstones 40 feet (12.2 m.) above Division B2a of Matthew's [1903, p. 21] Etcheminian, Dugald Brook, Indian River, eastern Cape Breton, Nova Scotia (S. W. Loper, 1903). Lingulella (Lingulepis) longinervis. Acrothyra sera?. 13p' (see 13p, 13g, 13f, and 13d".) (For stratigraphic position and association, see p. 134.) Middle Cambrian: Sandstone 45 feet (13.6 m.) above Division E2a of Matthew's [1903, p. 21] Etcheminian, Dugald Broo];:! Indian River, eastern Cape Breton, Nova Scotia (S. W. Loper, 1903). Lingulella (Lingulepis) longinervis. Acrothyra sera?. 13q. (For stratigraphic position and association, see p. 131.) Upper Cambrian: Shales of. the "Bretonian" division of Matthew's [1903, p. 45] section on Gillis Brook, East Bay, Cape Breton, Nova Scotia (S. W. Loper, 1903). Orusia lenticularis. - . - Bradoria robusta (Matthew). 13r (little different horizon from 13i). (For stratigraphic position and association, see p. 132.) Middle Cambrian: Sandstone of the " Johannian " division of Matthew's section on Gillis Brook, East Bay, east of Bras d'Or Lake, eastern Cape Breton, Nova Scotia (S. W. Loper, 1903). Lingulella tumida. Lingulella (Lingulepis) exigua. ... i3t. (For stratigraphic position and association, see p. 134.) Middle Cambrian; Sandstones at the base of Divi- sion Elb of Matthew's [1903, p. 21] Etcheminian, Dugald Brook, Indian River, eastern Cape Breton, Nova Scotia (S. W. Loper, 1903). *Lingulella triparilia. ., • I Acrothele prima. Lingulella tumida. .-,.-. 1 Acrothyra signata. Bassler cites the following: Bradoria rugulosa Matthew (emend.). Bradoria robusta (Matthew). Bradoria robusta n. var. 13t' (same locality as lOp; see 344k). (For stratigraphic position and association, see p. 134.) Middle Cambrian: Sandstones of Di\dsion Elb of Matthew's [1903, p. 21] Etcheminian, Dugald Brook, Indian River, eastern Cape Breton, Nova Scotia (S. W. Loper, 1903). Lingulella triparilis. 13t" (see 344m). (For stratigraphic position and association, see p. 134.) Middle Cambrian: Sandstones of Divi- sions Elc and Eld of Matthew's [1903, p. 21] Etcheminian, on Dugald Brook, Indian River, eastern Cape Breton, Nova Scotia (S. W. Loper, 1903). Lingulella triparilis. Lingulella (Lingulepis) gregwa. Acrothyra sera. Acrothyra signata. Bradoria robusta (Matthew). Bradoria concinna (Matthew). 184 CAMBRIAN BEACHIOPODA. Matthew [1903] cites the following as occurring in Id Lingulepis gregwa. Lingulepis gregwa robusta. Acrotreta papillata=Acrothyra sera. Acrotreta signata tarda=Acrothyra sera. Orthotheca sp. Bradorona observator Matthew. Bradorona observator benepuncta Matthew. Bradorona perspicator Matthew. Bradorona spectator Matthew. Bradorona spectator acuta Matthew. 14. (For stratigraphic position and association, see p. 147.) Middle Cambrian: Limestones overlying the sand- stones of the Rome formation, near the wagon road and in a quarry near the railroad track, 7 miles (11.2 km.) southwest of Rome [see Hayes, 1902, historical geology sheet], Floyd County, Ga. (C. D. Walcott, 1891). Micromitra (Iphidella) pannula. Billingsella appalachia? Dorypyge?. 14a. (For stratigraphic position and association, see p. 147.) Middle Cambrian: Sandstone of the Rome forma- tion, along First Creek Gap, 4 miles (6.4 km.) north-northeast of Knoxville [Keith, 1905, areal geology sheet], Knox County, Tenn. (M. R. Campbell, 1891). Micromitra alabamaensis. Obolus willisi. Obolus (Westonia) ella.' Lingulella similis. *Wimanella saffordi. 14b. Upper Cambrian: Limestone on Cold Creek, at north end of gorge opposite the north end of Sponge Moun- tain, 2 miles (3.2 km.) south of the San Saba County line, in Llano County, Tex. (J. A. Taff, E. 0. Ulrich^ and J. W. Beede). Obolus matinalis. *Obolus nundina. Obolus sinoe. Lingulella acutangula. Lingulella upis. Lingulella (Lingulepis) acuminata. Acrotreta microscopica. Billingsella coloradoensis. Eoorthis indianola?. Eoorthis remnicha texana. Eoorthis wichitaensis. Eoorthis wichitaensis Iseviusculus. 14c. Upper Cambrian: Upper part of the limestone exposed at Baldwin's ranch, on Cold Creek, 2.5 miles (4 km.) south of the San Saba County line, in Llano County, Tex. (E. O. Ubich). Obolus matinalis. 14e (see 14q). Upper Cambrian: Limestone in Bartlett Hollow, 2 miles (3.2 km.) southeast of the mouth of Falls Creek, Burnet quadrangle (U. S. G. S.), Lampasas County, Tex. (Bailey Willis, E. 0. Ulrich, and J. A. Taff). Obolus matinalis. Obolus sinoe. Acrotreta microscopica. 14g (=14i). (E. 0. Ulrich, J. A. Taff, and J. W. Beede.) Lingulella upis. Acrotreta microscopica. Billingsella coloradoensis. 14i (=14g). Upper Cambrian: Upper part of limestone exposed 1 mile (1.6 km.) west of Cherokee, San Saba County, Tex. (E. 0. Ubrich, J. A. Taff, and J. W. Beede). Lingulella acutangula. *Lingulella upis. Linnarssonella girtyi. 14k. Upper Cambrian: Limestone on Wolf Creek, 15 miles (24.2 km.) west-southwest of Sheridan, Bighorn Mountains, Sheridan County, Wyo. Eoorthis desmopleura. *Syntrophia rotundata. 141. (For stratigraphic position and association, see p. 138.) Lower Cambrian: Sandstones about 2,800 feet (853 m.) below the Middle Cambrian, in a horizon correlated with No. 2j of the Silver Peak group of the Waucoba Springs section [Walcott, 1908f, p. 187], in the pass about 7 miles (11.2 km.) east of Resting (Fresh- water) Springs, which is in the southwest corner of T. 21 N., R. 8 E., on Amargosa River, in the south- eastern part of Inyo County, Cal. (R. B. Rowe, 1901). •Billingsella bivia. Olenellus fremonti Walcott LOCALITIES. 185 14m. (For stratigraphic position and association, see p. 140.) Middle Cambrian: Limestone about 7 miles (11.2 km.) south of Towner's ranch, Indian Creek, Lincoln County, Nev. (R. B. Rowe, 1901). Lingulella arguta. 14n. Middle Cambrian: Limestone about 310 feet (94.5 m.) above the Lower Cambrian, on the east side of the pass about 7 miles (11.2 km.) east of Resting (Freshwater) Springs, which is the southwest comer of T. 21 N., R. 8 E., on Amargosa River, in the southeastern part of Inyo County, Cal. (R. B. Rowe, 1901). Obolus mcconnelli. Obolus mcconnelli decipiens. 14o. (For stratigraphic position and association, see p. 138.) Lower Cambrian: Sandstones about 3, .500 feet (1,067 m.) below the Middle Cambrian, in the pass about 7 miles (11.2 km.) east of Resting (Freshwater) Springs which is the southwest corner of T. 21 N., R. 8 E., on Amargosa River, in the southeastern part of Inyo County, Cal. (R. B. Rowe, 1901). Obolella sp. undt. 14p. (For stratigraphic position and association, see p. 138.) Lower Cambrian: Reddish-brown quartzitic sand- stone near Resting (Freshwater) Springs, which is in the southwest comer of T. 21 N., R. 8 E., on Amargosa River, in the southeastern part of Inyo County, Cal. (M. R. Campbell and R. B. Rowe, 1901). *Lingulella (Lingulepis) rowei. Obolella vermilionensis. Billingsella bivia. Wanneria gracile Walcott. Olenellus fremonti Walcott. Cystid plate. 14c( (see 14e). Upper Cambrian: Sandstone in Bartlett Hollow, 1.5 miles (2.4 km.) southeast of the mouth of Falls Creek, Burnet quadrangle (U. S. G. S.), Lampasas County, Tex. (E. 0. Ulrich). Obolus matinalis. 14r. Upper Cambrian: Sandstone in the lower part of the beds exposed on Colorado River, 3 miles (4.8 km.) south of the northeast comer of Llano County, Tex. (E. 0. Ulrich). Obolus matinalis. Lingulella (Lingulepis) acuminata. 14s. (For stratigraphic position and association, see p. 127.) Middle Cambrian: About 2,300 feet (701 m.) above the Lower Cambrian and 2,700 feet (823 m.) below the Upper Cambrian, in the Ogygopsis zone of the Stephen formation [Walcott, 1908f, p. 210], at the great "fossil bed" on the northwest slope of Mount Stephen, above Field on the Canadian Pacific Railway, British Columbia, Canada (W. D. Wilcox, 1894; Mr. and Mrs. C. D. Walcott and Mr. and Mrs. L. D. Burling, 1907). Micromitra (Iphidella) pannula. Micromitra (Iphidella) pannula ophirensis. *Obolus mcconnelli. *Obolus septalis. Acrothele colleni. *Acrotreta depressa. *Philhedra columbiana. *Nisusia alberta. Hyolithellus annulatus (Matthew). HyolitheUus flagellum (Matthew). Orthotheca corrugata Matthew. Orthotheca major Walcott. Hyolithes carinatus Matthew. Hyolithes sp. Stenotheca wheeleri Walcott. Platyceras bellianus Walcott. Platyceras romingeri Walcott. Scenella varians Walcott. Anomalocaris?? acutangula Walcott. 14t. Anomalocaris canadensis Whiteaves. Anomalocaris? whiteavesi Walcott. Agnostus mentis Matthew. Dorypyge (Kootenia) dawsoni (Walcott). Bathyuriscus occidentalis (Matthew). Bathyuriscus ornatus Walcott. Bathyuriscus pupa Matthew. Bathyuriscus rotundatus (Rominger). Karlia stephenensis Walcott. Neolenus granulatus Matthew =Neolenus serratus. Neolenus serratus (Rominger). Ogygopsis klotzi (Rominger). Oryctocephalus reynoldsi Reed. Oryctocephalus walkeri Matthew=Oryctocephalus rey- noldsi. Burlingia hectori Walcott. Ptychoparia cordillerae (Rominger). Ptychoparia palliseri Walcott. Zacanthoides spinosus (Walcott). (For stratigraphic position and association, see p. 157.) Middle Cambrian: Limestone lying on slope between the Cambrian quartzite and the massive blue limestone 100 feet (30.5 m.) above, Moimt Nebo Canyon, 3 miles (4.8 km.) southeast of Mona, Juab County, Utah (F. B. Weeks, 1908). Micromitra (Iphidella) pannula. Lingulella cf. similis. *Acrotreta neboensis. 186 CAilBEIAN BRACHIOPODA. 14v. (For stratigraphic position and association, see p. 156.) Middle Cambrian: Shales of unknown stratigraphic horizon collected 1 mile (1.6 km.) south of Rainbow Valley, House Range [see Walcott, 1908f,,Pl. XIII], Millard County, Utah. • .•„.n .,.r.,i. Obolus mcconnelli. 14x. Middle Cambrian: About 400 feet (122 m.) above the bottom of Tombstone Gulch, in the Abrigo limestone [Ransome, 1904, p. 3], in the northwest suburb of Bisbee [see Ransome, 1904, areal geology sheet], Cochise County, Ariz. (F. L. Ransome, 1903). Obolus tetonensis. Billingsella??. 15b. (For stratigraphic position and association, see p. 156.) Middle Cambrian: About 1,700 feet (518.2 m.) above the Lower Cambrian and 2,700 feet (823 m.) below the Upper Cambrian, in the shaly limestones and calcareous shales of the \\Tieeler formation [Walcott, 1908f, p. 181], near Swasey Spring, House Range [Walcott, 1908f, PI. XIII], Millard County, Utah (G. K. Gilbert, 1903). Acrothele subsidua. 15c. (For stratigraphic position and association, see p. 156.) Middle Cambrian: Mai-jum limestone [Walcott, 1908a, p. 10], near Swasey Spring, House Range [Walcott, 1908f, PI. XIII], Millard County, Utah (G. K. Gilbert, 1901). Nisusia (Jamesella) nautes?. Anomocare sp. 15d (same horizon as 33d). (For stratigraphic position and association, see p. 154.) Upper Cambrian: Thin- bedded blue limestone near Cave Spring, on the east side of the Fish Spring Range, about 4 miles (6.4 km.) south of the J. J. Thomas ranch, Juab County, Utah (G. K. Gilbert, 1901). Lingulella desiderata. *Lingulella isse. Lingulella manticula. Acrotreta idahoensis. Acrotreta idahoensis alta. 16p. (For stratigraphic position and association, see p. 155.) Middle Cambrian: Limestones near the north end of the Fish Spring Range, Tooele County, Utah (G. K. Gilbert, 1901). Obolus mcconnelli pelias. Lingulella desiderata. 15r. Middle Cambrian: Dark argillaceous shale at Khussak, Salt Range, India (F. Noetling, 1902). *Lingulella fuchsi. I *Botsfordia granulata. *Lingulella wanniecki. I Redlichia noetlingi Cossman. 15x. (For stratigraphic position and association, see p. 155.) Middle Cambrian: Limestones near the middle of the Fish Spring Range, near the line between Juab and Tooele counties, Utah (G. K. Gilbert, 1901). Obolus mcconnelli pelias. Lingulella desiderata. 16. (For stratigraphic position and association, see p. 147.) Middle Cambrian: Limestones in Conasauga ("Coosa ") limestone, Blountsville Valley, Blount County, Ala. Lingulella desiderata. *Lingulella nanno. Dicellomus appalachia. 16f (see 47d-f). Lower Cambrian: Sandstone at the mouth of Little Antietam Creek, near Eakles Mills, Wash- ington County, Md. (John Widgeon, 1903). Obolella minor. Syntrophia sp. undt. 16h (see 334h). (For stratigraphic position and association, see p. 145.) Middle Cambrian: Limestones of Para- doxides forchhammeri zone at Borregaard, Bornholm Island, Denmark (K. A. Gronwall, 1903). *Micromitra pusilla. Micromitra (Iphidella) ornatella. Obolus schmalenseei. Lingulella ferruginea. Acrothele coriacea. Acrothele intermedia. Acrotreta sagittalis. Acrotreta schmalenseei. Anomocare laeve Angelin. 161. (For stratigraphic position and association, see p. 146.) Middle Cambrian: Limestones of " Conocoryphe exsulans" zone at Borregaard, Bornholm Island, Denmark (K. A. Gronwall, 1903). Obolus schmalenseei. I Acrotreta sagittalis. Lingulella?. I Liocephalus impressa Linnarsson. LOCALITIES. 187 16j. (For stratigraphic position and association, see p. 145.) Middle Cambrian: 'Limestones oi Paradoxides forch- hammeri zone at Laesa^, Bornholm Island, Denmark (K. A. Gronwall, 1903). Micromitra pusilla. Lingulella feiTuginea. Acrotliele coriacea. Acrotreta sagittalis. Acrotreta schmalenseei. 16k. (For stratigrapliic position and association, seep. 146.) Middle Cambrian: Limestones of Paradoxides davidis zone at Laesa^, Bornholm Island, Denmark (K. A. Gronwall, 1903). Acrothele coriacea. Acrotreta sagittalis. 161. (For stratigraphic position and association, see p. 146.) Middle Cambrian: Limestones of Paradoxides davidis zone at Borregaard, Bornholm Island, Denmark (K. A. Gronwall,. 1903). Acrothele coriacea. . . Acrotreta sagittalis. 16n. Upper Cambrian: Interformational conglomerate and shales in Adams pasture, 0.5 mile (0.8 km.) west of Main Street, on Lake Street, St. Albans, Franklin Coimty, Vt. (Geo. H. Edson; H. E. Dickhaut, 1903). liingulella?. Lingulella (Lingulepis) acuminata. Yorkia sp. 16o. (For stratigraphic position and association, see p. 131.) Upper Cambrian: Shales on McMuUins Brook, in the East Boisdale district, eastern Cape Breton, Nova Scotia (S. W. Loper, 1903). Lingulella concinna. nh. (For stratigraphic position and association, see p. 147.) Lower Cambrian: Rome (" Monte vallo") formation 4 miles (6.4 km.) south of Helena, Shelby County, Ala. (C. D. Walcott, 1895). Micromitra (Paterina) major. ] Obolus smithi. Micromitra (Paterina) williardi. | *Wimanella shelbyensis. 17c. Middle Cambrian: Sandy limestone 235 feet (71.6 m.) above the "Tonto" sandstone. Grand View trail north of Last Chance copper mine, south side of the Grand Canyon of the Colorado, Arizona. *Obolus (Westonia) themis. Lingulella acutangula. Lingulella lineolata. 17j. Middle Cambrian: Limestone in the east end of the town of Galena, Black Hills, South Dakota. Lingulella similis. 17k. Middle Cambrian: Limestone thrown out on the dump of the Great Northern shaft, southeast of Twobit, northern Black Hills, Lawrence County, South Dakota. linnarssoneUa girtyi. 18. (For stratigraphic position and association, see p. 147.) Middle Cambrian: Limestone 1 mile (1.6 km.)east of Gap Creek, 13 miles (20.8 km.) S. 75° E. of Knoxville, Knox County, Tenn. (A. Keith and C. D. Walcott). Acrotreta kutorgai?. 20 (see 21a). Lower Cambrian: Limestone on the south side of Mettawee River, 0.25 mile (0.4 km.) above the North Granville bridge, Fort Ann quadrangle (U. S. G. S.), Washington County, N. Y. (C. D. Walcott, 1890). Obolella crassa. Medusa? sp. 20a. Lower Cambrian: Gray limestone interbedded with shaly slates in a lane west of Lafayette Stevens's house, about 100 yards (91.4 m.) from the main road in the southern part of ^Miitehall township, Fort Ann quad- rangle (U. S. G. S.), Washington County, N. Y. (C. D. Walcott, 1890). Lingulella granvillensis. Acrotreta sagittalis taconica. Hyolithellus micans (Billings). Microdiscus connexus Walcott. Olenellus?. Olenoides fordi Walcott. Ptychoparia sp. 21. Lower Cambrian: Shales 1.5 miles (2.4 km.) south of Salem, Cambridge quadrangle (U. S. G. S.), Washington County, N. Y. (C. D. Walcott, 1890). Billingsella salemensis. ArchEeocyathus dwighti Walcott. Stenotheca rugosa (Hall). Fordilla troyensis Barrande. Microdiscus lobatus (Hall). Olenellus. Solenopleura? tumida Walcott. Leperditia? dermatoides (Walcott). 188 CM'IBRIAN BRACHIOPODA. 21a. Lower Cambrian: Limestone below the first fall of Mettawee River, above the North Granville bridge. Fort Ann quadrangle (U. S. G. S.), Washington County, N. Y. (C. D. Walcott, 1890). LinguleUa granvillensis. I Olenellus?. Microdiscus connexus Walcott. | Ptychoparia ep. 22. Lower Cambrian: Limestone 1.5 miles (2.4 km.) north of North Granville, Fort Ann quadrangle (U. S. G. S.)^ Washington County, N. Y. (C. D. Walcott, 1891). Acrothele nitida. Acrotreta sagittalis taconica. Hyolithellus micans (Billings). Microdiscus lobatus (Hall). OleneUus. 22a. Lower Cambrian: Limestone in Penrhyn quarries, Middle Granville, Mettawee quadrangle (U. S. G. S.), Washington County, N. Y. (C. D. Walcott, 1890). LinguleUa sp. Acrotreta sagittalis taconica. Billingsella salemensis. 25. Lower Cambrian: Sandstone just above Parker's quarry, near Georgia, Franklin County, Vt. (C. D. Walcott. and Cooper Curtice, 1883). *Rustella edsoni. Micromitra (Paterina) bella. Nisusia festinata. *Nisusia festinata transversa. Medusa? sp. Eocystites? sp. *Mesonacis vermontana (Hall). *P8edeumias transitans Walcott. *01enellus thompsoni (Hall). Olenellus thompsoni crassimarginatus Walcott. Microdiscus parkeri Walcott. Ptychoparia adamsi (Billings). Ptychoparia vulcanus (Billings). Protypus senectus (Billings). Bathynotus holopyga (Hall). Olenoides marcoui (Whitfield). Lower Cambrian: Limestone on the Hall (Donaldson's) farm, 2 miles (3.2 km.) east of Swanton, Franklin: County, Vt. (C. D. Walcott and Cooper Curtice, 1883). Billingsella orientalis. Hyolithes sp. Salterella pulchella Billings. Olenellus thompsoni (Hall). Ptychoparia adamsi (Billings). Protypus senectus (Billings). 25a. *Micromitra (Paterina) labradorica swantonensis. Obolus cf. prindlei. LinguleUa granvillensis. Kutorgina cingulata. Nisusia festinata. Nisusia festinata transversa. 26. Lower Cambrian: Sandstone northeast of the Corman farm buildings, east of Highgate Springs, Franklia County, Vt. (C. D. Walcott and Cooper Curtice, Micromitra (Paterina) labradorica swantonensis. Nisusia festinata. Billingsella orientalis. Scenella varians Walcott. Hyolithes sp. 1883). Olenoides desiderata (Walcott). Ptychoparia adamsi (Billings). Ptychoparia teucer (Billings). Ptychoparia vulcanus (Billings). Ptychoparia sp. 27. Lower Cambrian: Even-bedded Troy quadrangle (U. S. G. S.), Obolella crassa. Bicia gemma. Botsfordia cselata. *Acrothele nitida. Archseocyathus rarus (Ford). Archseocyathus rensselKricum (Ford). Scenella retusa Ford. Stenotheca rugosa (Hall). Platyceras primsevum Billings. Hyolithellus micans Billings. and conglomerate limestones on the ridge in the eastern suburb of Troy,. Rensselaer County, N. Y. (Cooper Curtice, 1883). Hyolithes americanus Billings. Hyolithes communis Billings. Hyolithes communis emmonsi Ford. Hyolithes impar Ford. Hyolithes sp. Microdiscus lobatus (Hall). Microdiscus speciosus Ford. Elliptocephala asaphoides Emmons. Olenoides fordi Walcott. Solenopleura nana Ford. 27a. Lower Cambrian: Reddish sandstone about 1 mile (1.6 km.) east of Lansingburg, north of Troy, Cohoes; quadrangle (U. S. G. S.), Rensselaer County, N. Y. (Cooper Curtice, 1883). Obolella crassa. LOCALITIES. 189 28. Upper Cambrian: Shales about 100 feet (30.5 m.) above the Olenellus horizon, south of Highgate Falls 0.25 mile (0.4 km.) east of Swanton, Franklin County, Vt. (C. D. Walcott, 1884). *Protorthis wingi. Hyolithes sp. Ptychoparia adamsi (Billings.) 28a. Middle? Cambrian: ''St. Albans formation," in limestone lentile about 1 mile (1.6 km.) east of Parker's quarry, near Georgia, Franklin County, Vt. (C. D. Walcott, 1884). Lingulella franklinensis. *Huenella billingsi. Ptychoparia adamsi (Billings). 29 (see 338b). Lower Cambrian: Limestone just above the bridge at the Stockport paper mill, on Kinderhook Creek, Columbia County, N. Y. (C. D. Walcott and S. W. Ford). Obolus prindlei. Lingulella gran-\dllensis. Acrotreta sagittalis taconica. 29a (see 338). Lower Cambrian: Limestone 1 mile (1.6 km.) below the New York Central Railroad 'depot at Schodack Landing, Rensselaer County, N. Y. (C. D. Walcott and S. W. Ford). Obolella crassa. Botsfordia cselata. Bicia gemma. Acrotreta sagittalis taconica. Hyolithellus micans (Billings). Hyolithes americanus Billings. Microdiscus lobatus (Hall). Microdiscus speciosus Ford. Elliptocephala asaphoides Emmons. 30. (For stratigraphic position and association, see p. 158.) Lower Cambrian: Limestone 8 miles (12.8 km.) north of Bennetts Spring, on the west slope of the Highland Range, Lincoln County, Nev. (C. D. Walcott and J. E. W., 1885). Micromitra (Iphidella) pannula. Obolus (Westonia) ella. Billingsella highlandensis. Callavia nevadensis Walcott. Olenellus fremonti Walcott. Olenellus gilberti (Meek). Peachella iddingsi Walcott. Sponge?. Crepicephalus augusta Walcott. Crepicephalus liliana Walcott. 30a. (For stratigraphic position and association, see p. 158.) Middle Cambrian: Shale onnorth side of Big Cotton- wood Canyon, 1 mile (1.6 km.) below Argenta, in the Wasatch Mountains, southeast of Salt Lake City, Salt Lake County, Uta,h (C. D. Walcott and J. E. W., 1885). Isoxys argentea (Walcott). Ptychoparia quadrans (Hall and ^Tiitfield). Bathyuriscus productus (Hall and Whitfield). Olenoides wasatchensis (Hall and TMiitfield). Micromitra (Iphidella) pannula. Obolus (Westonia) ella. Lingulella helena. Hyolithellus sp. Hyolithes billingsi Walcott. Walcott [1886] wrongly includes Cruziana and Olenellus gilberti in this fauna (see Walcott, 1891b, p. 319) 30c (^llw). (For stratigraphic position and association, see p. 157.) (C. D. Walcott, F. B. Weeks, and L. D. Burling, 1905.) Micromitra (Paterina) labradorica utahensis. Ptychoparia 2 sp. 30d. (For stratigraphic position and association, seep. 157.) Middle Cambrian: About 1,020 feet (310.9 m.) above the Lower Cambrian and 3,400 feet (1,036.3 m.) below the L'pper Cambrian, in the limestone forming le of the Swasey formation [Walcott, 1908f, p. 182], at the head of Dome Canyon, about 2 miles (3.2 km.) west- southwest of Antelope Springs, House Range [Walcott, 1908f, PL XIII], Millard Coimty, Utah (F. B. Weeks, 1905). Obolus (Westonia) ella. Ptychoparia, several species. 30e. (For stratigraphic position and association, seep. 158.) Middle Cambrian: About 100 feet (30.5 m.) above the Lower Cambrian and 4,300 feet (1,310.6 m.) below the Upper Cambrian, in the limestones forming la of the Langston (?) limestone [Walcott, 1908f, p. 183], in Dome Canyon, House Range [Walcott, 1908f, PL XIII], Millard County, Uuh (C. D. Walcott, F. B. Weeks, and L. D. Burling, 1905). Billingsella sp. undt. Zacanthoides. Hyolithes. Ptychoparia. Leperditia?. Dorypyge?. 190 CAMBRIAN BRACHIOPODA. 30g (=llq and lly; same horizon as 3w). (For stratigraphic position and association, see p. 156.) Middle Cam- brian: About 2,350 feet (716.3 m.) above the Lower Cambrian and 2,050 feet (624.8 m.) below the Upper Cambrian, in the limestone forming Ic of the Marjum limestone j^Valcott, 1908f, p. 180], 2.5 miles (4 km.) east of Antelope Springs, in ridge east of Wheeler Amphitheater [Walcott, 1908f, Pis. XIII andXVJ, House Range, Millard County, Utah (C. D. Walcott, F. B. Weeks, and L. D. Burling, 1905). Obolus mcconnelli pelias. Acrothele subsidua. Acrotreta ophirensis. Acrotreta cf. ophirensis. Hyolithes. Crinoidal fragments. Sponge. Ogygopsis?. Agnostus 2 sp. Ptychoparia 3 sp. Solenopleura. Neolenus inflatus Walcott. Neolenus intermedius Walcott. Neolenus intermedius pugio Walcott. Neolenus superbus Walcott. 30h. (For stratigraphic position and association, seep. 154.) Upper Cambrian: About 350 feet (106.7 m.) above the Middle Cambrian and 2,950 feet (899.2 m.) below the top of the Upper Cambrian, near the base of the arenaceous limestones forming 2a of the Orr formation [Walcott, 1908f, p. 177], on Orr Ridge, about 5 miles (8 km.) south of Marjum Pass, House Range [Walcott, 1908f, PI. XIII], Millard County, Utah (F. B. Weeks, 1905). Lingulella desiderata. Acrotreta idahoensis. Acrotreta idahoensis sulcata. Crepicephalus texanus (Shumard). Bathyuriscus. Illsenurus?. 30j. (For stratigraphic position and association, seep. 154.) Upper Cambrian: About 950 feet (289.6 m.) above the Middle Cambrian and 2,450 feet (746.8 m.) below the top of the Upper Cambrian, near the base of the arenaceous shales and limestones forming le of the Orr formation [VValcott, 1908f, p. 176], on Orr Ridge, about 5 miles (8 km.) south of Marjum Pass, House Range [Walcott, 1908f, PI. XIII], Millard County, Utah (C. D. Walcott, F. B. Weeks, and L. D. Burling, 1905). *Linnarssonella transversa. Agnostus. Crepicephalus. Micromitra (Paterina) crenistria. Obolus mcconnelli pelias. Lingulella desiderata. Lingulella isse. 30k (25 feet below 31t at same locality). (For stratigraphic position and association, see p. 154.) Upper Cambrian: 1,150 feet (350.5 m.) above the Middle Cambrian and 2,175 feet (662.9 m.) below the top of the Upper Cam- brian, at the top of the arenaceous shales and limestones forming le of the Orr formation [Walcott, 1908f, p. 176], on Orr Ridge, about 5 miles (8 km.) south of Marjum Pass, House Range [Walcott, 1908f, PI. XIII], Millard County, Utah (C. D. Walcott, F. B. Weeks, and L. D. Burling, 1905). Lingulella desiderata. Ptychoparia?. Lingulella isse. Solenopleura. *Linnarssonella modesta. 30 1 (30y is the metamorphosed equivalent of this at different locality) . (For stratigraphic position and association, seep. 153.) Upper Cambrian: About 1,400 feet (426.7 m.) above the Middle Cambrian and 1,900 feet (579.1 m.) below the top of the Upper Cambrian, in the shales forming lb of the Orr formation [Walcott, 1908f, p. 176], on Orr Ridge, about 5 miles (8 km.) south of Marjum Pass [Walcott, 1908f, PI. XIII], House Range, Millard County, Utah (C. D. Walcott, F. B. Weeks, and L. D. Burling, 1905). Lingulella manticula. I Ptychaspis. Section of crinoid column. ] Anomocare. 30m. (For stratigraphic position and association, see p. 153.) Upper Cambrian : About 1,950 feet (584.4 m.)abovethe Middle Cambrian and 1,350 feet (411.5 m.) below the top of the Upper Cambrian, in the siliceous limestones forming leof the Notch Peak limestone [Walcott, 1908f, p. 175], on the slopes of Notch Peak, about 5 miles (8 km.) southwest of Marjum Pass, House Range [Walcott, 1908t, P!. XIII], Millard County, Utah (C. D. Walcott, F. B. Weeks, and L. D. Burling, 1905). *Obolus tetonensis leda. 30n (=30n'). (For stratigraphic position and association, see p. 155.) Middle Cambrian: About 3,750 feet (1,143 m.) above the Lower Cambrian and 650 feet (198 m.) below the Upper Cambrian, in the shaly limestones form- ing Ic of the Weeks limestone [Walcott, 1908f, p. 175], on the north side of Weeks Canyon, about 4 miles (6.4 km.) south of Marjum Pass, House Range [W'alcott, 1908f, PI. XIII], Millard County, Utah (C. D. Wal- cott and L. D. Burling, 1905). *Obolus (Fordinia) perfectus. Lingulella isse. Acrotreta ophirensis. *Acrotreta ophirensis descendens. Hyolithes. Agnostus, several species. Ptychoparia, several species. Asaphiscus sp. Crepicephalus texanus (Shumard). Neolenus. Solenopleura. LOCALITIES. 191 30n' (=30n, but in slightly higher beds). (For stratigraphic position and association, see p. 155.) (C. D. Walcott and L. D. Burling, 1905.) 30o (=14v). (For stratigraphic position and association, see p. 154.) Middle Cambrian: About 3,950 feet (1,204 m.) above the Lower Cambrian and 450 feet (137.2 m.) below the Upper Cambrian, in the shaly limestones form- ing lb of the Weeks limestone [Walcott, 1908f, p. 178], on the north side of Weeks Canyon, about 4 miles (6.4 km.) south of Marjum Pass, House Range [Walcott, 19081, PI. XIII], Millard County, Utah (C. D. Wal- cott and L. D. Burling, 1905). Obolus (Fordinia) perfectus. Asaphiscus sp. Agnostus, several species. Ptychoparia. Crepicephalus texanus (Shumard). Bathyuriscus. Anomocare?. Solenopleura. 30p. (For stratigraphic position and association, see p. 151.) Middle Cambrian: About 125 feet (38 m.) above the Cambrian quartzitic sandstones on the north side of Ogden Canyon, about 1 mile (] .'6 km.) above its mouth, east of Ogden, Weber County, Utah (F. B. Weeks and L. D. Burling, 1905). Micromitra (Paterina) labradorica utahensis. Obolus mcconnelli. Obolus (Westonia) eUa. 30q. (For stratigraphic position and association, seep. 149.) Upper Cambrian: Limestones about 2,300 feet (701 m.) above the Cambrian quartzitic sandstones on pipe line above limekiln in Ogden Canyon, 1 mile (1.6 km.) above its mouth, east of Ogden, Weber County, Utah (F. B. Weeks and L. D. Burling, 1905). Obolus rotundatus. Lingulella manticula. 30s. (For stratigraphic position and association, see p. 149.) Upper Cambrian: Green shale about 1,200 feet (365.8 m.) above the Cambrian quartzitic sandstones on pipe line above limekiln in Ogden Canyon, 1 mile (1.6 km.) above its mouth, east of Ogden, Weber County, Utah (L. D. Burling, 1905). Lingulella isse. 30u. (For stratigraphic position and association, see p. 151.) Middle Cambrian: Sandy shales about 250 feet (76.2 m.) above the top of the Cambrian quartzitic sandstones 4 miles (6.4 km.) northwest of Promontory Point station (on the "Lucin cut-off" of the Union Pacific Railway), about halfway up west end of ridge, north of Great Salt Lake, Boxelder County, Utah (F. B. Weeks. 1905). Micromitra (Paterina) labradorica utahensis. Acrotreta cf. ophirensis. 30w. (For stratigraphic position and association, see p. 153.) Upper Cambrian: Drift bowlder of limestone supposed to have come from the beds forming la of the Notch Peak limestone oa Notch Peak [Walcott, 1908f , p. 175], found about 2 miles (3.2 km.) south of Marjum Pass, House Range [Walcott, 1908f, PI. XIII], Millard County, Utah (C. D. Walcott and F. B. Weeks, 1905). Schizambon typicalis. Eoorthis desmopleura. Agraulos. Solenopleura. Illsenurus. 30y (the metamorphosed equivalent of 30 1 at a different locality). (For stratigraphic position and association, see p. 153.) Upper Cambrian: About 1,400 feet (426.7 m.) above the Middle Cambrian and 1,900 feet (579.1 m.) below the top of the Upper Cambrian, in the supposed metamorphosed equivalent of the shales forming lb of the Orr formation [Walcott, 19081, p. 176], above the granite contact on top of the ridge north of Notch Peak [Walcott, 1908f, Pis. XIII and XIV], House Range, Millard County, Utah (C. D. Walcott, F. B. Weeks, and L. D. Burling, 1905). Obolus rotundatus. Lingulella isse. Anomocare. 30z. (For stratigraphic position and association, see p. 156.) Middle Cambrian: About 2,450 feet (746.8 m.) above the Lower Cambrian and 1,950 feet (594.4 m.) below the Upper Cambrian, in the upper part of the limestone forming Ic of the Marjum limestone [Walcott, 19081, p. 180], in the long cliff about 2 miles (3.2 km.) south- east of Marjum Pass, House Range [Walcott, 19081, Pis. XIII and XV], Millard County, Utah (C. D. Walcott. F. B. Weeks, and L. D. Burling, 1905). Acrotreta pyxidicula. Agnostus. Ptychoparia. 192 CAMBRIAN BRACHIOPODA. 31. (For stratigraphic position and association, seep. 158.) Middle Cambrian: Shales at the Chisholm mine, southwest slope of Ely Mountains, 3 miles (4.8 km.) northwest of Pioche, Lincoln County, Nev. (C. D. Walcott and J. E. W., 1885). Micromitra (Iphidella) pannula. . Obolus (Westonia) ella. *Lingulella dubia. Eocystites longidactylus Walcott. Hyolithes billingsi Walcott. Zacanthoides typicalis (Walcott). Ptychoparia piochensis Walcott. Anomocare parvum Walcott. Bathyuriscus howelli Walcott. Bathyuriscus productus (Hall and Whitfield). 31a. (For stratigraphic position and association, seep. 158.) Lower Cambrian: Limestone and interbedded sili- ceous shales of the Pioche formation [Walcott, 1908a, p. 11], just above the quartzite on the east side of the anticline, near Pioche, Lincoln County, Nev. (C. D. Walcott and J. E. W., 1885). *Micromitra (Iphidella) pannula. *Acrothele spurri. *Acrothele subsidua hera. *Acrotreta primseva. *Biningsella highlandensis. Hyolithes billingsi Walcott. Bellerophon antiquatus Whitfield. *01enellus gilberti (Meek). Olenoides sp. Oryctocephalus primus Walcott. Zacanthoides levis (Walcott). Crepicephalus augusta Walcott. Crepicephalus liliana Walcott. Ptychoparia sp. 31o (=54o; same horizon as 32e). (For stratigraphic position and association, see p. 151.) Middle Cambrian: About 900 feet (274.3 m.) above the Brigham quartzite and 3,300 feet (1,006.5 m.) below the Upper Cambrian, in the limestone forming lb of the Ute limestone [Walcott, 1908f, p. 196], in Blacksmith Fork Canyon, about 10 miles (16.1 km.) east of Hyrum, Cache County, Utah (L. D. Burling, 1905). Obolus mcconnelli. Acrotreta cf. ophirensis. Acrotreta sp. undt. Otusia utahensis. Eoorthis zeno. Syntrophia cambria. Zacanthoides. Ptychoparia subcoronata (Hall and Whitfield). Dorypyge ? quadriceps (Hall and Whitfield). 31d (=541). (For stratigraphic position and association, seep. 152.) Middle Cambrian: About 500 feet (152.4 m.) above the Brigham quartzite and 3,700 feet (1,127.8 m.) below the Upper Cambrian, in the Spence shale member of the Ute limestone [Walcott, 1908f, p. 197], in Blacksmith Fork Canyon, about 10 miles (16.1 km.) east of Hyrum, Cache County, Utah (F. B. Weeks, 1905). Obolus (Westonia) ella?. Ptychoparia. 31e (=54a). (For stratigraphic position and association, see p. 151.) Middle Cambrian: About 750 feet (228.6 m.) above the Brigham quartzite and 3,440 feet (1,048.5 m.) below the Upper Cambrian, in the shales forming 2a of the Ute limestone [Walcott, 1908f, p. 196], in Blacksmith Fork Canyon, about 10 miles (16.1 km.) east of Hyrum, Cache County, Utah (L. D. Burling, 1905). Obolus (Westonia) ella. Ptychoparia. 31h (=55n). (For stratigraphic position and association, see p. 150.) (F. B. Weeks, 1905.) 311 (=54h). (For stratigraphic position and association, see p. 149.) Middle Cambrian: About 3,140 feet (957.1 m.) above the Brigham quartzite and 1,050 feet (320 m.) below the Upper Cambrian, in the limestones forming la of the Bloomington formation [Walcott, 1908f, p. 194], in Blacksmith Fork Canyon, about 9 miles (14.4 km.) east of Hyrum, Cache County, Utah (L. D. Burling, 1905). Lingulella desiderata. Agnostus. 31m (=55h). (For stratigraphic position and association, see p. 149). Upper Cambrian: About 175 feet (53.3 m.) above the Middle Cambrian and 1,050 feet (320 m.) below the top of the Upper Cambrian, near the base of the limestones forming 3 of the St. Charles limestone [Walcott, 1908f, p. 192], in Blacksmith Fork Canyon, about 9 miles (14,4 km.) east of Hyrum, Cache County, Utah (L. D. Burling, 1905). Obolus sp. undt. Agnostus. Lingulella manticula. Ptychoparia. Billingsella coloradoensis. 31a (=55g). (For stratigraphic position and association, see p. 149.) Upper Cambrian: About 250 feet (76.2 m.) above the Middle Cambrian and 975 feet (297.2 m.) below the top of the Upper Cambrian, in the upper part of the limestone forming 3 of the St. Charles limestone [Walcott, 1908f, p. 192], in Blacksmith Pork Canyon, about 9 miles (14.4 km.) east of Hyrum, Cache County, Utah (L. D. Burling, 1905). Acrotreta? sp. ' Anomocare. LOCALITIES. 193 31q. (For stratigraphic position and association, see p. 153.) Upper Cambrian: About 2,800 feet (853.4 m.) above the Middle Cambrian and 500 (152.4 m.) below the top of the Upper Cambrian, in the gray limestone forming la of the Notch Peak limestone [T\^alcott, 1908f, p. 175], north slope of Notch Peak, House Range [Walcott, 1908f, Pis. XIII and XIV], Millard County, Utah (F. B. Weeks, 1905). Lingulella isse. Dikellocephalus?. 31s. (For stratigraphic position and association, see p. 157.) Middle Cambrian: 490 feet (149.4 m.) above the Lower Cambrian and 3,925 feet (1,196.3 m.) below the Upper Cambrian, in the pinkish argillaceous shale forming Id of the Howell formation [Walcott, 1908f, p. 182], south side of Dome Canyon, about 1 mile (1.6 km.) below the divide and 3 miles (4.8 km.) west-southwest of Antelope Springs, House Range [Walcott, 1908f, PL XIII], Millard County, Utah (C. D. Walcott and F. B. Weeks, 1905). Micromitra (Iphidella) pannula. Obolus (Westonia) ella. Acrothele spurri. Acrotreta cf . ophirensis. Scenella. Hyolithes. Zacanthoides. Bathyuriscus. Bit (25 feet above 30k at same locality). (For stratigraphic position and association, see p. 154.) Upper Cambrian: About 1,175 feet (358.1 m.) above the Middle Cambrian and 2,150 feet (655.3 m.) below the top of the Upper Cambrian, in the limestone forming Id of the Orr formation [Walcott, 1908f, p. 176], on Orr Ridge, about 5 miles (8 km.) south of Marjum Pass, House Range [Walcott, 1908f, PI. XIII], Millard County, Utah (L. D. Burling, 1905). Linnarssonella modesta. I Solenopleura. *Linnarssonella nitens. I Protaspis. 31u. (For stratigraphic position and association, see p. 158.) Middle Cambrian: Shales on west slope of spur facing the main part of the Highland Range, 3 miles (4.8 km.) northwest of Pioche, Lincoln County, Nev. Walcott [1891b, p. 318] cites the following species from this locality: Lingulella ella=Obolus (Westonia) ella. Kutorgina pannula=Micromitra (Iphidella) pannula. Eocystites?? longidactylus Walcott. Hyolithes bUlingsi Walcott. Ptychoparia piochensis Walcott. Zacanthoides typicalis (Walcott). Bathyuriscus howelli Walcott. Bathyuriscus productus (Hall and Whitfield). 31v. (For stratigraphic position and association, see p. 157.) Middle Cambrian: 650 feet (198.1 m.) above the Lower Cambrian and 3,750 feet (1,143 m.) below the Upper Cambrian, in shales at the top of the limestone forming la of the Howell formation [Walcott, 1908f, p. 182], northeast side of Dome Canyon, about 4 miles (6.4 km.) west-southwest of Antelope Springs, House Range [Walcott, 1908f, Pis. XIII and XTVI], Millard County, Utah (C. D. Walcott, F. B. Weeks, and L. D. Burling, 1905). Micromitra (Iphidella) pannula. Acrotreta cf . ophirensis. Ptychoparia. Sly. (For stratigraphic position and association, seep. 151.) Middle Cambrian: Thin-bedded limestone about 125 feet (38 m.) above the Cambrian quartzitic sandstones in the Wasatch Mountains, 1 mile (1.6 km.) north- west of Geneva (Copenhagen), east of Brigham, Boxelder County, Utah (F. B. Weeks and L. D. Burling, 1905). Obolus mcconnelli. Lingulella isse. 31z (=55t). (For stratigraphic position and association, see p. 151.) Middle Cambrian: About 350 feet (106.7 m.) above the Brigham quartzite, in the limestone of the Ute limestone [Walcott, 190Sa, p. 7], on west side of road, 0.5 mile (0.8 km.) above the forks, Paradise Dry Canyon (locally known as East Fork), east of Para- dise, Cache County, Utah (F. B. Weeks, 1905). Otusia utahensis. Acrotreta ophirensis. 32. Lower Cambrian: Sandstone on the south slope of Stissing Mountain, Dutchess County, N. Y. (C. D. Wal- cott, 1886). *Obolella minor. Obolella sp. Elliptocephala asaphoides Emmons. 32a. Lower Cambrian: Limestone, 0.75 mile (1.2 km.) west of Riders Mill station on the Harlem Extension Rail- road, about 9 miles (14.4 km.) north-northeast of Chatham, Kinderhook quadrangle (U. S. G. S.), Colum- bia County, N. Y. (C. D. Walcott and T. N. Dale, 1891). Bicia gemma. Acrotreta sagittalis taconica. 62667°— VOL 51, PT 1—12 13 194 CMIBRIAN BRACHIOPODA. 32c. (For stratigraphic position and association, see p. 152.) Middle Cambrian: About 60 feet (18.3 m.) above the Brigham quartzite [Walcott, 1908a, p. 8], in green shale 1 mile (1.6 km.) northwest of Geneva (Copen- hagen), east of Brigham, Boxelder County, Utah (L. D. Burling, 1905). Acrotreta cf . ophirensis. 32(1. (For stratigraphic position and association, see p. 152.) Middle Cambrian: Shales about 150 feet (45.7 m.) above the Brigham quartzite [Walcott, 1908a, p. 8], on the east side of the south fork of Paradise Dry Canyon (locally known as East Fork), east of Paradise, Cache County, Utah (F. B. Weeks, 1905). Micromitra (Paterina) labradorica utahensis. Obolus (Westonia) ella. 32e (same horizon as 31c and 54o). (For stratigraphic position and association, see p. 151.) Middle Cambrian: About 900 feet (274.3 m.) above the Brigham quartzite and 3,300 feet (1,005.8 m.) below the Upper Cambrian, in limestone corresponding to that forming lb of the Ute limestone [Walcott, 1908f, p. 196], just south of the south fork of Paradise Dry Canyon (locally known as East Fork), east of Paradise, Cache County, Utah (L. D. Burling, 1905). ' Otusia utahensis. *Syntrophia cambria. 32f. (For stratigraphic position and association, see p. 153.) Upper Cambrian: Thin-bedded siliceous limestone near the top of the Upper Cambrian, about 2 miles (3.2 km.) southeast of Muskrat Spring, on the northwest face of Grantsville Peak, Stansbury Range, Tooele County, Utah (F. B. Weeks and L. D. Burling, 1905). Lingulella manticula. Lingulella pogonipensis. 32g. (For stratigraphic position and association, see p. 154.) Upper Cambrian: About 2,575 feet (784.9 m.) above the Cambrian quartzitic sandstones, in a blue limestone about 2 miles (3.2 km.) southeast of Muskrat Spring, on the northwest face of Grantsville Peak, Stansbury Range, Tooele County, Utah (L. D. Burling, 1905). Obolus mcconnelli pelias. I Lingulella isse. Lingulella desiderata. I Linnarssonella nitena. 32h. (For stratigraphic position and association, see p. 157.) Middle Cambrian: Shales in a canyon on the west side of the Simpson Range, 4 miles (6.4 km.) south of Simpson Spring, about 20 miles (32.2 km.) west-south- west of Vernon, Tooele County, Utah (F. B. Weeks and L. D. Burling, 1905). Obolus (Westonia) ella. 32j. (For stratigraphic position and association, see p. 157.) Middle Cambrian: 625 feet (190.5 m.) above the Cambrian quartzitic sandstones, in pinkish-colored very fine grained arenaceous shale 2 miles (3.2 km.) southeast of Muskrat Spring, on the northwest face of Grantsville Peak, Stansbury Range, Tooele County, Utah (L. D. Burling, 1905). Acrotreta cf. ophirensis. 32k. (For stratigraphic position and association, see p. 156.) Middle? Cambrian: Limestones about 1,550 feet (472.4 m.) above the top of the Cambrian quartzitic sandstones 2 miles (3.2 km.) southeast of Muskrat Spring, on the northwest face of Grantsville Peak, Stansbiiry Range, Tooele County, Utah (L. D. Burling, ' 1905). Obolus mcconnelli. 32n. (For stratigraphic position and association, see p. 151.) Middle Cambrian: Shales about 725 feet (221 m.) above the Brigham quartzite [Walcott, 1908a, p. 8], in the Wasatch Mountains, 1 mile (1.6 km.) northwest of Geneva (Copenhagen), Boxelder County,' Utah (L. D. Burling, 1905). Obolus (Westonia) ella?. 32o. (For stratigraphic position and association, see p. 158.) Middle Cambrian: Shale about 325 feet (99 m.) above the Cambrian quartzitic sandstones 2 miles (3.2 km.) southeast of Muskrat Spring, on the northwest face of Grantsville Peak, Stansbury Range, Tooele County, Utah (L. D. Bm-ling, 1905). Obolus (Westonia) ella. 32p (=55e). (For stratigraphic position and association, see p. 152.) (L. D. Burling, 1905.) Obolus (Westonia) ella. Acrothele subsidua. 32t. (For stratigraphic position and association, see p. 154.) Upper Cambrian: Limestone about 3,650 feet (1,112.5 m.) above the Cambrian quartzitic sandstones in Fandango Spring canyon, on the east side of the Dugway Range, about 5 miles (8 km.) north of where the stage road between Vernon and Deep Creek crosses the divide, Tooele County, Utah (L. D. Burling, 1905). Linnarssonella girtyi. LOCALITIES. 195 32x (=54k faunally). (Forstratigraphic position and association, see p. 150.) Middle Cambrian: About 1,700 feet (518.2 m.) above the Brigham quartzite [Walcott, 1908a, p. 8], in shales correlated with the shales forming 2d of the Bloomington formation in Blacksmith Fork Canyon [Walcott, 1908f, p. 195], Wasatch Canyon, east of Lakeview ranch, 5 miles (8 km.) north of Brigham, Boielder County, Utah (L. D. Burling, 1905). Obolus (Westonia) wasatchensis. 32y. (For stratigraphic position and association, see p. 151.) Middle Cambrian: Shales about 175 feet (53.3 m.) above the Brigham quartzite [Walcott, 1908a, p. 8], in the Wasatch Mountains, 1 mile (1.6 km.) northwest of Geneva (Copenhagen), east of Brigham, Boxelder County, Utah (F. B. Weeks and L. D. Burling, 1905). Obolus (Westonia) ella. 32z (below 32h at same locality). (For stratigraphic position and association, see p. 157.) Middle Cambrian: Shales in a canyon on the west side of the Simpson Range, 4 miles (6.4 km.) south of Simpson Spring, about 20 miles (32.2 km.) west-southwest of Vernon, Tooele County, Utah (F. B. Weeks and L. D. Burling, 1905). Obolus (Westonia) ella. 33 (see 338c). Lower Cambrian: Limestone on the roadside near Rock Hill schoolhouse, near North Greenwich, about 5 miles (8 km.) north-northeast of Greenwich, Cambridge quadrangle (U. S. G. S.), Washington County, N. Y. (C. D. Walcott, 1886). Botsfordia cselata. Acrotreta sagittalis taconica. Billingsella salemensis. Archseocyathus dwighti Walcott. • Hyolithellus micans (Billings). Hyolithes americanus Billings. Hyolithes communis Billings. Hyolithes impar Ford. Stenotheca elongata Walcott. Stenotheca rugosa (Hall). Microdiscus lobatus (Hall). Microdiscus speciosus Ford. Elliptocephala asaphoides Emmons. Zacanthoides eatoni Walcott. Ptychoparia cf. adamsi (Billings). Protypus clavatus Walcott. Solenopleura tumida Walcott. 33b. Lower Cambrian: Limestone, 1.5 miles (2.4 km.) east-southeast of North Greenwich, about 5 miles (8 km.) north-northeast of Greenwich, Cambridge quadrangle (U. S. G. S.), Washington County, N. Y. (C. D. Walcott, 1886). Botsfordia cselata. Hyolithellus micans (Billings). Hyolithes communis Billings. Microdiscus lobatus (Hall). Microdiscus speciosus Ford. Elliptocephala asaphoides Emmons. 33d (same horizon as 15d). (For stratigraphic position and association, see p. 154.) Upper Cambrian: Thin-bedded blue limestone at the base of the first high point southwest of the J. J. Thomas ranch, on the east side of the Fish Spring Range, Juab County, Utah (L. D. Burling, 1905). Obolus mcconnelli pelias. Obolus rotundatus. Lingulella isse. Schizambon typicalis. Acrotreta marjumensis. 33f. (For stratigraphic position and association, see p. 157.) Middle Cambrian: Shales about 400 feet (122 m.) above the Cambrian quartzitic sandstones on the western slope of the high peak southwest of Lookout Pass, Onaqui Range, west of Vernon, Tooele County, Utah (L. D. Burling, 1905). *Obolus (Westonia) ella onaquiensis. Obolus (Westonia) cf. ella onaquiensis. 33i. (For stratigraphic position and association, see p. 158.) Lower Cambrian: About 100 feet (30.5 m.) above the Prospect Mountain quartzite, in the shale of the Pioche formation [Walcott, 1908f, p. 171], 0.25 mile (0.4 km.) below the Maxfield mine, Big Cottonwood Canyon, west front of the Wasatch Mountains southeast of Salt Lake City, Salt Lake County, Utah (L. D. Burling, 1905). Obolus (Westonia) ella. 33j. (For stratigraphic position and association, see p. 149.) Middle Cambrian: Shale about 2,300 feet (701 m.) above the Brigham quartzite [Walcott, 1908a, p. 8], in Wasatch Canyon, east of Lakeview ranch, 5 miles (8 km.) north of Brigham, Boxelder County, Utah (L. D. Burling, 1905). Obolus (Westonia) wasatchensis. 331. (For stratigraphic position and association, see p. 153.) Upper Cambrian: Limestones in pass between the Pavant Mountains and the Canyon Range, a few hundred yards east of the divide, on the road between Holden and Scipio, Millard County, Utah (L. D. Burling, 1905). Eoorthis desmopleura. Solenopleura. Illeenurus. 196 CMIBRIAN BRACHIOPODA. 33n. (For stratigraphic position and association, see p. 154.) Middle? Cambrian: Limestone pebbles, west front of the Pavant Mountains, collected in the wash at the mouth of Crow Creek, about 4 miles (6.4 km.) east of Fillmore, Millard County, Utah (L. D. Burling, 1905). Acrotreta idahoensis alta. 33r. (For stratigraphic position and association, see p. 157.) Middle Cambrian: Limestones faulted against the Cambrian quartzites in a canyon about 1 mile (1.6 km.) east of Cricket Spring, Cricket Range (locally known as the Beaver River Range or the Beaver Mountains), northwest of Black Rock. Millard County, Utah (L. D. Burling, 1905). *Otusia utahensis. 33t. (For stratigraphic position and association, see p. 150.) Middle Cambrian: Shale about 1,500 feet (457.2 m.) above the Brigham quartzite [Walcott, 1908a, p. 8], 1 mile (1.6 km.) northwest of Geneva (Copenhagen), east of Brigham, Boxelder County, Utah (F. B. Weeks, 1905). Obolus (Westonia) wasatchensis. 34. Lower Cambrian: Limestone on roadside a little west of the bridge over Poultney River at Low Hampton, about 5 miles (8 km.) east-northeast of Whitehall, Whitehall quadrangle (U. S. G. S.), Washington County, N. Y. (C. B. Walcott, 1886). Micromitra (Iphidella) pannula. Lingulella granvillensis. Botsfordia cselata. Acrotreta sagittalis taconica. Platyceras primsevum Billings. Hyolithes communis Billings. Microdiscus connexus Walcott. Microdiscus lobatus (Hall). Microdiscus speciosus Ford. Elliptocephala asaphoides Emmons. Ptychoparia cf. adamsi (Billings). Ptychoparia fitchi Walcott. Solenopleura tumida Walcott. Zacauthoides eatoni Walcott. 34a. Lower Cambrian: Limestones 1 mile (1.6 km.) west of North Hebron, 5 miles (8 km.) south-southwest of Granville, Fort Ann quadrangle (U. S. G. S.), Washington County, N. Y. (C. D. Walcott, 1886). Botsfordia cselata. Microdiscus lobatus (Hall). Microdiscus speciosus Ford. 34g. (For stratigraphic position and association, see p. 153.) Passage beds between the Cambrian and Ordovician: Limestones about 1,000 feet (305 m.) above the valley on the east side of the Fish Spring Range, just west of the high point southwest of the J. J. Thomas ranch, Juab County, Utah (L. D. Burling, 1905). Eoorthis desmopleura. 34i. (For stratigraphic position and association, see p. 154.) Upper Cambrian: Shales about 1 mile (1.6 km.) northeast of Sand Pass, at the south end of the Fish Spring Range, Juab County, Utah (C. D. Walcott and L. D. Burling, 1905). Obolus rotundatus. Lingulella desiderata. Lingulella isse. 34ni. (For stratigraphic position and association, see p. 151.) Middle Cambrian: Limestone about 765 feet (233.2 m.) above the Brigham quartzite [Walcott, 1908a, p. 8], 1 mile (1.6 km.) northwest of Geneva (Copenhagen), east of Brigham, Boxelder County, Utah (L. D. Burling, 1905). Micromitra (Paterina) labradorica utahensis. Syntrophia cambria. 34n. (For stratigraphic position and association, see p. 158.) Middle Cambrian: Shales about 100 feet (30.5 m.) above the Tintic quartzite [G. O. Smith, 1900, p. 1], near the summit of the ridge between Mammoth and Eureka, Tintic special quadrangle (U. S. G. S.), Juab County, Utah (F. B. Weeks, 1905). Obolus mcconnelli. Obolus rotundatus. 34c[. (For stratigraphic position and association, see p. 149.) Upper Cambrian: Shales about 3,800 feet (1,158.2 m.) above the Brigham quartzite [Walcott, 1908a, p. 8], in Wasatch Canyon, east of Lakeview Ranch, about 5 miles (8 km.) north of Brigham, Boxelder County, Utah (L. D. Burling, 1905). Obolus mcconnelli pelias. Acrotreta idahoensis alta. 34r. (For stratigraphic position and association, see p. 154.) Upper Cambrian: Limestones 1.5 miles (2.4 km.) northwest of Wahwah Spring, about halfway up the section to the north of the road at Cane Pass, Wahwah Mountains, Beaver County, Utah (F. B. Weeks, 1905). Obolus rotundatus. Lingulella isse. LOCALITIES. 197 34s. (For stratigraphic position and association, see p. 156.) Middle Cambrian: About 1,700 feet (518 m.) above the Tintic quartzite, in the Mammoth limestone of G. O. Smith [1900, p. 1, and historical geology sheet], in the saddle above and a little east of the Centennial Eureka mine, near the summit of the ridge between Mammoth and Eureka, Tintic special quadrangle (U. S. G. S.), Juab County, Utah (F. B. Weeks, 1905). Obolus mcconnelli. 34t. (For stratigraphic position and association, see p. 154.) Upper Cambrian: Limestone 1.5 miles (2.4 km.) northwest of Wahwah Springs, about 80 feet (24.4 m. ) below the highest point on the north side of the road at Cane Pass, Wahwah Mountains, Beaver County, Utah (F. B. Weeks, 1905). Lingulella desiderata. Lingulella isse. 34u. (For stratigraphic position and association, see p. 157.) Middle Cambrian: Shales about 950 feet (289.6 m.) above the Cambrian quartzitic sandstones 2 miles (3.2 km.) southeast of Muskrat Spring, on the northwest face of Grantsville Peak, Stansbury Range, Tooele County, Utah (L. D. Burling, 1905). Obolus (Westonia) wasatchensis. 34v. (For stratigraphic position and association, see p. 155.) Middle? Cambrian: Limestone about 1,750 feet (533 m.) above the Cambrian quartzitic sandstones about 2 miles (3.2 km.) southeast of Muskrat Spring, on the northwest face of Grantsville Peak, Stansbury Range, Tooele County, Utah (L, D. Burling, 1905). Obolus mcconnelli pelias. 35. Lower Cambrian: Limestones 1.5 miles (2.4 km.) north of Bald Mountain and 3.5 miles (5.6 km.) north- northwest of Greenwich, Schuylerville quadrangle (IT. S. G. S.), Washington County, N. Y. (C. D. Walcott, 1886). Obolus prindlei. Lingulella granvillensis. Obolella crassa. Botsfordia cselata. Acrotreta sagittalis taconica, Stenotheca rugosa (Hall). Platyceras primaevum Billings. Hyolithellus micans (Billings). Hyolithellus micans rugosa Walcott. Hyolithes communis Billings. Elliptocephala asaphoides Emmons. Solenopleura tumida Walcott. 35a. Lower Cambrian: Shaly limestone on the west slope of the summit of Bald Mountain, 3 miles (4.8 km.) north-northwest of Greenwich, Schuylerville quadrangle (U. S. G. S.), Washington County, N. Y. (C D Walcott, 1886). Botsfordia cselata. *Acrotreta emmonsi. Olenellus sp. 35c. (For stratigraphic position and association, see p. 130.) Lower Cambrian: Drift blocks of siliceous shale supposed to have come from the Mount Whyte formation [W'alcott, 1908f, p. 214], found on the south slope of Mount Bosworth, about 500 feet (152 m.) northwest of the Canadian Pacific Railway track between Stephen and Hector, eastern British Columbia, Canada (Mr. and Mrs. C. D. Walcott and Mr. and Mrs L D Burline 1907). ■ ■ ■ ^' *Micromitra (Paterina) wapta. *Obolus parvus. Acrothele colleni. Wimanella simplex. Hyolithellus. Hyolithes. *Albertella bosworthi Walcott. *Albertella helena Walcott. Bathyuriscus. Agraulos. Ptychoparia. Bathyuriscus. 35d. (For stratigraphic position and association, see p. 130.) Lower Cambrian: About 3,150 feet (960.1 m.) below the Middle Cambrian, in the siliceous Lake Louise shale [Walcott, 1908f, p. 216], in cliff on the north side of Lake Louise, at its upper end, southeast of Laggan, on the Canadian Pacific Railway, Alberta, Canada (Mr. and Mrs. C. D. Walcott and Mi-, and Mrs. L. D. Burling, 1907). *Micromitra (Iphidella) louise. Cruziana. Annelid trails. 35e. (For stratigraphic position and association, see p. 130.) Lower Cambrian: About 270 feet (82.3 m.) below the Middle Cambrian, in a greenish siliceous shale correlated with No. 3 of the Mount Whyte formation on Mount Bosworth [Walcott, 1908f, p. 214], in the amphitheater between Popes Peak and Mount '\\Tiyte, about 3 miles (4.8 km.) northwest of Lake Louise, southwest of Laggan on the Canadian Pacific Railway, Alberta, Canada (C. D. Walcott and L. D. Burling, 1907). Micromitra (Paterina) wapta. Obolus parvus. Acrothele colleni. Hyolithes billingsi Walcott. Olenopsis. Ptychoparia sp. Albertella sp. Bathyuriscus. Olenellus gilberti (Meek). Micromitra (Iphidella) pannula var. Kutorgina cingulata. Kutorgina?. Acrotreta sagittalis taconica. Nisusia festinata. Hyolithes billingsi Walcott. 198 CAMBRIAN BRACHIOPODA. 35f. (For stratigraphic position and association, see p. 130.) Lower Cambrian: About 300 feet (91 m.) below the Middle Cambrian, in the limestone forming 6 of the Mount WTiyte formation [Walcott, 1908c, p. 242 (11)], just above the tunnel on the north shoulder of Mount Stephen, about 3 miles (4.8 km.) east of Field, British Columbia, Canada (C. D. Walcott and L. D. Burling, 1907). Scenella varians Walcott. Ptychoparia 3 sp. Agraulos sp. Protypus sp. Olenellus canadensis Walcott. Olenellus gilberti (Meek). 35g. (For stratigraphic position and association, see p. 126.) Middle Cambrian: About 4,100 feet (1,250 m.) above the Lower Cambrian and 860 feet (262 m.) below the Upper Cambrian, in the shaly limestones in 2 of the Eldon limestone [Walcott, 1908f, p. 209], at the north end of the amphitheater northwest of the main ridge of Mount Bosworth, north of the Canadian Pacific Railway between Hector and Stephen, on the Continental Divide between British Columbia and Alberta, Canada (C. D. Walcott and L. D. Burling, 1907). Obolus mcconnelli var. I Isoxys cf. argentea (Walcott). *Obolus membranaceus. I Ptychoparia 3 sp. 35h. (For stratigraphic position and association, see p. 130.) Lower Cambrian: About 375 feet (114 m.) below the Middle Cambrian, in the shales of No. 4 of the Mount Whyte formation [W^alcott, 1908f, p. 214], on Mount Bosworth, north of the Canadian Pacific Railway between Hector and Stephen, on the Continental Divide between British Columbia and Alberta, Canada (Mr. and Mrs. C. D. Walcott, Mr. and Mrs. L. D. Burling, and Helen and Stuart Walcott). Agraulos. Olenellus canadensis Walcott. Olenellus gilberti (Meek). Nisusia festinata. Scenella varians Walcott. Hyolithellus. Ptychoparia. 35k. (For stratigraphic position and association, see p. 127.) Middle Cambrian: Burgess shale member of the Stephen formation on the west slope of the ridge between Mount Field and Wapta Peak, 1 mile (1.6 km.) northeast of Burgess Pass, above Field, British Columbia (Mr. and Mrs. C. D. Walcott and Stuart Walcott, 1909 and 1910. )« *Micromitra zenobia. | Micromitra (Iphidella) pannula. *Micromitra (Paterina) stissingensis ora. | Nisusia alberta. 36 (see 338d). Lower Cambrian: Limestone 1 mile (1.6 km.) south of Shushan and 3.5 miles (5.6 km.) north- northeast of Cambridge, Cambridge quadrangle (U. S. G. S.), Washington County, N. Y. (C. D. Walcott, 1886). Hyolithes communis Billings. Microdiscus speciosus Ford. Elliptocephala asaphoides Emmons. Solenopleura tumida Walcott. 36b. Lower Cambrian: Limestone near schoolhouse No. 12, near Greenwich, Cambridge quadrangle (U. S. G. S.), Washingtoh County, N. Y. (O. C. Tefft, 1887). Acrotreta sagittalis taconica. Nisusia festinata. * Billingsella salemensis. Hyolithellus micans (Billings). Hyolithellus micans (Billings). Microdiscus lobatus (Hall). Microdiscus sp. Obolus prindlei. Botsfordia caelata. Acrotreta sagittalis taconica. 37. Lower Cambrian: Limestone 1.5 miles (2.4 km.) south of Salem, Cambridge quadrangle (U. S. G. S.), Washing- ton County, N. Y. (C. D. Walcott, 1886). Billingsella salemensis. 37b. Lower Cambrian: Limestone 0.25 mile (0.4 km.) east of Salem, Cambridge quadrangle (U. S. G. S.), Wash- ington County, N. Y. (C. D. Walcott, 1893). Olenellus?. Microdiscus connexus Walcott. Lingulella granvillensis. *Yorkia washingtonensis. Acrotreta sagittalis taconica. 38. Lower Cambrian : Limestone 0.25 mile (0.4 km.) north of John Hulett's farmhouse, about 3 miles (4.8 km.) west of South Granville, and 4,5 miles (7.2 km.) southwest of Granville, Fort Ann quadrangle (U. S. G. S.), Washington County, N. Y. (C. D. Walcott, 1886). Lingulella granvillensis. Botsfordia cselata. Stenotheca elongata Walcott. Hyolithes impar Ford. Elliptocephala asaphoides Emmons. a This is the locality containing the beautifully preserved annelids, medusiE, eurypterids, holothurians, crustaceans, etc, now being described and illustrated in volume 57 of the Smithsonian Miscellaneous Collections. LOCALITIES. 199 38a. Lower Cambrian: Limestone 2 miles (3.2 km.) south of North Granville, on the road which turns south from the road running between that village and Truthville, 4 miles (6.4 km.) west-northwest of Granville, Fort Ann quadrangle (U. S. G. S.), Washington County, N. Y. (C. D. Walcott, 1886). Micromitra (Iphidella) pannula. Oboliis prindlei. *Lingulella granvillensis. Lingulella sp. Botsfordia cselata. Yorkia? washingtonensis. Acrotreta emmonsi. *Acrotreta sagittalis taconica Nisusia festinata. Protospongia sp. Platyceras primsevum Billings Hyolithellus micans (Billings). Hyolithellus micans rugosa Walcott. Hyolithes americanus Billings Hyolithes impar Ford. Agnostus sp. Microdiscus connexus Walcott. Microdiscus lobatus (Hall). Microdiscus speciosus Ford. Elliptocephala asaphoides Emmons. Ptychoparia cf. adamsi (Billings). Ptychoparia fitchi Walcctt. Ptychoparia sp. Protypus clavatus Walcott. Zacanthoides eatoni Walcott. Olenoides fordi Walcott. 38c. Lower Cambrian: Shale at the slate quarries on the west side of the valley 1 mile (1.6 km.) north of Middle Granville, Mettawee quadrangle (U. S. G. S.), Washington County, N. Y. (C. D. Walcott, 1886). Botsfordia cselata. 39. Lower Cambrian : Limestone south of the Delaware and Hudson Railroad track, on the road running south- 3 km.) east-northeast of Whitehall, Whitehall quadrangle Walcott, 1886). Microdiscus speciosus Ford. Protypus clavatus Walcott. southwest from Low Hampton, about 5 miles (U. S. G. S.), Washington County, N. Y. (C. D Botsfordia ceelata. Acrotreta sagittalis taconica. Archseocyathus dwighti Walcott. 39a. Lower Cambrian: Limestone 0.25 mile (0.4 km.) north of Easton Station, 3 miles (4,8 km.) south of Green wich, Cambridge quadrangle (U. S. G. S.), Washington County, N. Y. (C. D. Walcott, 1887). Botsfordia cselata. Hyolithellus micans rugosa Walcott. Microdiscus lobatus (Hall). 41 (same horizon as 5 1). Walcott, 1891b, p Walcott, 1888). *Obolella atlantica. Hyolithellus micans (Billings). Helenia bella Walcott. Hyolithes princeps Billings. Hyolithes quadricostatus Shaler and Foerste. Hyolithes similis Walcott. Hyolithes sp. Stenotheca rugosa (Hall). Stenotheca rugosa acuticosta Walcott. Stenotheca rugosa erecta Walcott. Stenotheca rogosa Isevis Walcott. Stenotheca rugosa pauper Billings. (For stratigraphic position and association, see p. 141.) Lower Cambrian: Sandstone [see 260, for position in section] on Manuels Brook, Conception Bay, Newfoundland (C. 1). Coleoloides typicalis Walcott. Microdiscus bellimarginatus Shaler and Foerste. Microdiscus helena Walcott. Callavia broggeri (Walcott). Ptychoparia attleborensis Shaler and Foerste. Ptychoparia sp. Solenopleiua bombifrons Matthew. Solenoplem'a howleyi Walcott. Avalonia manuelensis Walcott. Agraulos strenuus Billings. Agraulos strenuus nasutus Walcott. Agraulos sp. Walcott [1891b, p Hyolithes impar Ford. Hyolithes terranovicus Walcott. Scenella reticulata Billings. 60] cites the following additional species: Platyceras primsevum Billings. Microdiscus speciosus Ford. 41a. (For stratigraphic position and association, see p. 141.) Lower Cambrian: Limestone [see Walcott, 1891b, p. 260] on the mainland beneath Topsail Head, Conception Bay, Newfoundland. Micromitra (Paterina) labradorica. Obolella atlantica. Scenella reticulata Billings. Hyolithellus micans (Billings). Hyolithellus micans rugosa Walcott. Hyolithes impar var. Hyolithes princeps Billings. Microdiscus bellimarginatus Shaler and Foerste. Ptychoparia attleborensis Shaler and Foerste. Avalonia manuelensis Walcott. Agraulos strenuus Billings. Walcott [1891b, p. 260] cites the following additional species: Microdiscus speciosus Ford. Microdiscus sp. undt. Callavia broggeri (Walcott). Solenopleura bombifrons Matthew. Agi'aulos sp. 200 CAMBRIAN BRACHIOPODA. 43. Ordovician: Shales on the summit of Moses Hill, 2 miles (3.2 km.) west of North Greenwich, near the line between the Schuylerville and Cambridge quadrangles (U. S. G. S.), Washington County, N. Y. (C. D. Wal- cott, 1887). Acrothele pretiosa. 43a. Lower Cambrian: Limestone 1 mile (1.6 km.) east-northeast of Salem, Cambridge quadrangle(U. S. G. S.), Washington County, N. Y. (C. D. Walcott and W. P. Rust, 1887). Botsfordia ceelata. Acrotreta sagittalis taconica. Protospongia sp. Hyolithes impar Ford. Microdiscus connexus Walcott. Microdiscus lobatus (Hall). Microdiscus speciosus Ford. Agnostus desideratus Walcott. Ptychoparia cf. adamsi (Billings). Protypus clavatus Walcott. Zacanthoides eatoni Walcott. 44a (a little north of 44b). Lower Cambrian: Limestone on Valatie Kill, near the line between Nassau and Scho- dack townships, near line between Troy and Kinderhook quadrangles (U. S. G. S.), Rensselaer County, N. Y. (C. D. Walcott, 1887). Acrotreta sagittalis taconica. Microdiscus connexus Walcott. 44b (a little south of 44a). Lower Cambrian: Limestone near North Chatham, in the northern part of the Kinder- hook quadrangle (U. S. G. S.), Columbia County, N. Y. (C. D. Walcott, 1887). Micromitra (Iphidella) pannula. Lingulella granvillensis. Acrotreta sagittalis taconica. Hyolithellus micans (Billings). Agnostus sp. 45a. Lower Cambrian: Limestone at McNaughton Corner, 1 mile (1.6 km.) east of Salem, Cambridge quadrangle (U. S. G. S.), Washington County, N. Y. (Ira Sayles, 1887). Acrotreta sagittalis taconica. Archaeocyathus dwighti Walcott. Archseocyathus rarus (Ford). Hyolithellus micans (Billings). Microdiscus lobatus (Hall). Microdiscus speciosus Ford. Solenopleura tumida Walcott. Zacanthoides eatoni Walcott. 45b. Lower Cambrian: Limestone near the roadside about 1,200 feet (366 m.) east of Bristol's house, near Low Hampton, about 5 miles (8 km.) east-northeast of Whitehall, Whitehall quadrangle (U. S. G. S.), Wash- ington County, N. Y. (Ira Sayles, 1887). Obolus prindlei. Acrotreta sagittalis taconica. Platyceras primaevum Billings. Hyolithellus micans (Billings). Hyolithes americanus Billings. Hyolithes impar Ford. Microdiscus speciosus Ford. Elliptocephala asaphoides Emmons. Solenopleura tumida Walcott. 47a. Lower Cambrian: Sandstone on the southwest side of Sailings Mountain, 2 miles (3.2 km.) east of Natural Bridge, Rockbridge County, Va. (C. D. Walcott, 1891). *Kutorgina sp. undt. . | Hyolithes communis Billings. Obolella minor. I Olenellus sp. 47c. Lower Cambrian: Sandstone 2 miles (3.2 km.) west of bridge at Harpers Ferry, Jefferson County, W. Va. (C. D. Walcott, 1892). Obolella minor. Olenellus thompsoni (Hall). 47d (see 16f). Lower Cambrian: Sandstones 1 mile (1.6 km.) east-southeast of Smithsburg, Washington County, Md. (C. D. Walcott, 1892'' Obolella minor?. Olenellus thompsoni (Hall). 47e (see 16f). Lower Cambrian: Sandstone on Observatory Hill, 2 miles (3.2 km.) south of Keedysville, Wash- ington County, Md. (C. D. Walcott, 1892). Obolella minor. Olenellus thompsoni (Hall). 47f (see 16f). Lower Cambrian: Sandstone at Eakles Mills, 2 miles (3.2 km.) south of Keedysville, Washington County, Md. (C. D. Walcott, 1892). Obolella minor. Olenellus thompsoni (Hall). LOCALITIES. 201 4:7h. Middle Cambrian: Shales on Wolf Creek, 6 miles (9.6 km.) below Rocky Gap, Bland County, Va. (M. R. Campbell, 1893). Dicellomus appalachia. 48d. Middle Cambrian: Argillaceous shales in railroad cut alongside of gas house, city of York, York County, Pa. (H. E. Dickhaut, 1901). *Lingulella sp. undt. b. *Acrothele yorkensis. 49. Lower Cambrian: Sandstone on Codorus Creek 0.125 mile (0.2 km.) below Meyer's mill, near Emigsville, York County, Pa. (Charles Schuchert, 1893). Rustella edsoni?. Micromitra (Paterina) bella. *Yorkia wanneri. Nisusia festinata. Olenellus thompsoni crassimarginatus Walcott. 49a. Lower Cambrian: Sandstone on the Liverpool road, south of the schoolhouse, 3 miles (4.8 km.) northwest of York, York County, Pa. (Charles Schuchert, 1893). Rustella edsoni. I Nisusia festinata. Yorkia wanneri. I Olenellus thompsoni crassimarginatus Walcott. 49b. Lower Cambrian: Sandstone in the continuation of the ridge mentioned in Locality 49c, 2 miles (3.2 km.) northwest of Emigsville, York County, Pa. (C. D. Walcott, 1892). Obolella minor. Olenellus thompsoni (Hall). 49o. Lower Cambrian: Sandstone in ridge just north of the railway station at Emigsville, York County, Pa. (C. D. Walcott, 1892). Obolella minor. Olenellus thompsoni (Hall). 49d. Lower Cambrian: Sandstone 3 miles (4.8 km.) east of Waynesboro, Franklin County, Pa. (C. D. Walcott, 1892). Obolella minor. Olenellus thompsoni (Hall). 49e. Lower Cambrian: Sandstone 1 mile (1.6 km.) south of Mount Zion Church and 4 miles (6.4 km.) northeast of York, York County, Pa. (C. D. Walcott, 1892). Obolella minor. Olenellus thompsoni (Hall). 49f. Lower Cambrian: Sandstones of Mount Holly Gap, South Mountain, Cumberland County, Pa. (C. D. Wal- cott, 1892). Obolella minor?. Hyohthessp. Olenellus? sp. 49w. Lower Cambrian: Limestone in railroad cut 0.2.5 mile (0.4 km.) south of Emigsville, York County, Pa. (C. D. Walcott, 1892). Micromitra (Paterina) bella. Nisusia festinata. 50. Lower Cambrian: Shaly limestones 1.125 miles (1.8 km.) north of Stoner, 10 miles (16.1 km.) east-northeast of York, York County, Pa. (C. D. Walcott, 1892). *Acrothele decipiens. Olenellus. 50a. Lower Cambrian: Sandstone 2 miles (3.2 km.) northwest of York, York County, Pa. (C. D. Walcott, 1892). Obolella crassa?. Olenellus sp. 52. (For stratigraphic position and association, see p. 140.) Lower Cambrian: Arenaceous shales just above the Prospect Mountain quartzite, in a stratigraphic position similar to that of the Pioche formation [Walcott, 1908f, p. 184], at the top of Prospect Mountain, Eureka district [Hague, 1892, Atlas], Eureka County, Nev. (J. P.' Iddings and C. D. Walcott, 1880). *Micromitra (Paterina) prospectensis. Girvanella sp. Scenella? conula Walcott. Callavia nevadensis Walcott. Olenellus fremonti Walcott. Peachella iddingsi (Walcott). Dorypyge ? quadriceps (Hall and Whitfield). 202 GMIBRIAN BRACIIIOPODA. 63 (below 178a). (Forstratigraphic position and association, see p. 138.) Lower Cambrian: Sandstones in the lower portion of 3d of the Waucoba Spring.*) section [Walcott, 1908f, pp. 187 and 188], 1 mile (1.6 km.) east of Saline Valley road, about 2.5 miles (4 km.) east-northeast of Waucoba Springs, Inyo County, Cal. (C. D. Walcott, 1897)! Mickwitzia occidens. Obolella vermilioneusis. *Treraatobolus excelsis. Archseocyathus . Ethmophyllum gracile Meek. Hyolithes sp. Wanneria gracile Walcott. 53a. (For stratigraphic position and association, see p. 138.) Obolella sp. S4. (For stratigraphic position and association, seep. 140.) Middle Cambrian: Eldorado limestone [Walcott, 1908f, p. 184] on east slope of Prospect Mountain, in New York Canyon, Eureka district [Hague, 1892, Atlas], Eureka County, Nev. (C. D. Walcott, 1886). Lingulella arguta. Lingulella punctata. 54a (=31e). (For stratigraphic position and association, see p. 151.) (C. D. Walcott and L. D. Burling, 1906.) Micromitra (Paterina) labradorica utahensis. Obolus (Westonia) ella. Acrothele turner! ?. Isoxys cf. argentea (Walcott). Ptychoparia. 54b. (Forstratigraphic position and association, see p. 148.) Upper Cambrian: About 1,200 feet (365.8m.) above the Middle Cambrian and 25 feet (7.6 m.) below the top of the Upper Cambrian, in the upper part of the limestone forming 1 of the St. Charles limestone [Walcott, 1908f, p. 191], in Blacksmith Fork Canyon, about 10 miles (16.1 km.) east of Hyrum, Cache County, Utah (C. D. Walcott and L. D. Burling, 1906). Lingulella manticula. ' I Syntrophia nundina. Eoorthis desmopleura. | Dikellocephalus. 54c. (For stratigraphic position and association, see p. 148.) Upper Cambrian: About 1,100 feet (335.3 m.) above the Middle Cambrian and 120 feet (36.6 m.) below the top of the Upper Cambrian, in the central part of the limestone forming 1 of the St. Charles limestone [Walcott, 1908f, p. 192], in Blacksmith Fork Canyon, about 10 miles (16.1 km.) east of Hyrum, Cache County, Utah (C. D. Walcott and L. D. Burling, 1906). Schizambon typicalis. Eoorthis desmopleura. *Eoorthis newberryi. Syntrophia nundina. Solenopleura. Menocephalus. Illaenurus. 54d. (For stratigraphic position and association, see p . 148 . ) Upper Cambrian : About 1 ,050 feet (320 m . ) above the Middle Cambrian and 175 feet (53.3 m.) below the top of the Upper Cambrian, in the lower part of the lime- stone forming 1 of the St. Charles limestone [Walcott, 19081, p. 192], in Blacksmith Fork Canyon, about 10 miles (16.1 km.) east of Hyrum, Cache County, Utah (C. D. Walcott and L. D. Burling, 1906). Lingulella (Lingulepis) acuminata. Eoorthis desmopleura. Eoorthis newberryi. Agnostus. Menocephalus. Solenopleura. Asaphus?. 64e. (For stratigraphic position and association, see p. 149.) Upper Cambrian: About 200 feet (61 in.) above the Middle Cambrian and 1,025 feet (212.4 m.) below the top of the Upper Cambrian, in limestones forming 3 of the St. Charles limestone [Walcott, 1908f, p. 193], in Blacksmith Fork Canyon, about 10 miles (16.1 km.) east of Hyrum, Cache County, Utah (Mrs. C. D. Walcott, Stuart Walcott, and L. D. Burling, 1906). Obolus discoideus. Obolus (Westonia) ella. Lingulella manticula. Billingsella coloradoensis. *Huenella lesleyi. 541. Hyolithes. Cyrtolites. Agnostus. Ptychoparia. Anomocare. (For stratigraphic position and association, see p. 149.) Upper Cambrian : 150 feet (45.7 m.) above the Middle Cambrian and 1,075 feet (327.7 m.) below the top of the Upper Cambrian, in the light-gray sandstone forming 4 of the St. Charles limestone [Walcott, 1908f, p. 193], in Blacksmith Fork Canyon, about 10 miles(16.1 km.) east of Hyrum, Cache County, Utah (C. D. Walcott and L. D. Burling, 1906). Obolus discoideus. ' I Acrotreta idahoensis alta. Obolus (Fordinia) bellulus?. I Billingsella coloradoensis. LOCALITIES. 203 54g. (For stratigrapMc position and association, see p. 149.) Upper Cambrian : Just above the Middle Cambrian, near the base of the bedded light-gray sandstone forming 4 of the St. Charles limestone [Walcott, 1908f, p. 193], in Blacksmith Fork Canyon, about 10 miles (16.1 km.) east of Hyrum, Cache County, Utah (C. D. Walcott and L. D. Burling, 1906). Lingulella (Lingulepis) acuminata. 54]i (=311). (For stratigraphic position and association, see p. 149.) (L. D. Burling and Stuart Walcott, 1906.) Protospongia. Obolus mcconnelli peUas. Obolus (Westonia) wasatchensis. Lingulella desiderata. Hyolithes. Agnostus. Ptychoparia. 541 (=31k). (For stratigraphic position and association, seep. 150.) Middle Cambrian : About2,950feet(899.2m.) above the Brigham quartzite and 1,225 feet (373.4 m.) below the Upper Cambrian, in the limestone forming le of the Bloomington formation [Walcott, 1908f, p. 194], in Blacksmith Fork Canyon, about 10 miles (16.1 km.) east of HjTum, Cache County, Utah (L. D. Burling, 1905). Micromitra cE. sculptilis. | Agraulos. Hyohthes. • | Ptychoparia. 54], (For stratigraphic position and association, see p. 148.) Upper Cambrian: About 700 feet (213.4 m.) above the Middle Cambrian and 525 feet (160 m.) below the top of the Upper Cambrian, in the arenaceous limestones forming 2c of the St. Charles limestone [Walcott, 1908f, p. 192], in Blacksmith Fork Canyon, about 10 miles (16.1 km.) east of Hyrum, Cache County, Utah (C. D. Walcott, Stuart Walcott, and L. D. Burling, 1906). Obolus (Westonia) iphis. Lingulella desiderata. 54k. (For stratigraphic position and association, seep. 150.) Middle Cambrian: About 2, lOOfeet (640m.) above the Lower Cambrian and 2,100 feet (640 m.) below the Upper Cambrian, in the shales forming 2d of the Bloom- ington formation [V\^alcott, 1908f, p. 195], in Blacksmith Fork Canyon, about 10 miles (16.1 km.) east of Hyrum, Cache County, Utah (C. D. Walcott and L. D. Burling, 1906). Obolus (Westonia) wasatchensis. Agraulos. Ptychoparia. 541 (=31d). (For stratigraphic position and association, see p. 152.) (C. T>. Walcott, 1906.) Micromitra (Iphidella) pannula. Obolus (Westonia) ella?. Lingulella desiderata. Hyolithes. Orthotheca major Walcott. Leperditia. Ptychoparia. Bathyuriscus productus (Hall and Whitfield). 64m(=31f). (For stratigraphic position and association, seep. 150.) Middle Cambrian: About 1,225 feet (373.4 m.) above the Brigham quartzite and 2,950 feet (899.2 m.) below the Upper Cambrian, in the upper part of the limestone forming la of the Ute limestone [Walcott, 1908f, p. 195], in Blacksmith Fork Canyon, about 10 miles (16.1 km.) east of Hyrum, Cache County, Utah (C. D. Walcott and L. D. Burling, 1906). *Micromitra (Paterina) labradorica utahensis. BiUingsella sp. Hyohthes. Ptychoparia subcoronata (Hall and WTiitfield). Dorypyge? quadriceps (Hall and Whitfield). 54n. (For stratigraphic position and association, see p. 151.) Middle Cambrian: About 550 feet (167.6 m.) above the Brigham quartzite and 3,640 feet (1,109.5 m.) below the Upper Cambrian, in the limestone forming 2e of the Ute limestone [Walcott, 1908f, p. 197], in Blacksmith Fork Canyon, about 10 miles (16.1 km.) east of Hyrum, Cache County, Utah (C. D. Walcott, 1906). Dorypyge (fragment) . Ptychoparia. *Micromitra (Paterina) stuarti. Micromitra (Paterina) superba Hyohthes. 54o (=31c). (For stratigraphic position and association, see p. 151.) (C. D. Walcott and L. D. Burling, 1906.) Micromitra (Paterina) labradorica utahensis. BiUingsella coloradoensi *Eoorthis zeno. Syntrophia Cambria. Hyohthes. Scenella. Ptychoparia subcoronata (Hall and 'WTaitfield.) Dorypyge? quadriceps (Hall and "Whitfield.) 54p. (For stratigraphic position and association, see p. 151.) Middle Cambrian: About 525 feet (160 m.) above the Brigham quartzite and 3,665 feet (1,127.1 m.) below the LTpper Cambrian, in the shales forming 2f of the Ute limestone [Walcott, 1908f, p. 197], in Blacksmith Fork Canyon, about 10 miles (16.1 km.) east of Hyrum, Cache County, Utah (C. D. Walcott and L. D. Burling, 1906). Micromitra (Paterina) superba. Obolus mcconnelli. Ptychoparia sp. undt. ' 204 CAMBRIAN BEACHIOPODA. 84q (same horizon as 32x). (For stratigraphic position and association, see p. 150.) Middle Cambrian: A drift block supposed to have come from a horizon 1,700 feet (518.2 m.) above the Brigham quartzite [Walcott, 1908a, p. 8], found near the mouth of Wasatch Canyon, east of Lakeview ranch, 5 miles (8 km.) north of Brigham, Boxelder County, Utah (C. D. Walcott, 1906). Micromitra (Iphidella) pannula?. Obolus sp. undt. *Obolus (Westonia) wasatchensis. 64r. Acrothele subsidua. Nisusia alberta. Nisusia alberta?. (For stratigraphic position and association, see p. 148.) Upper Cambrian: Drift pieces of limestone from the west slope of the Wasatch Range, east of Lake\aew ranch, about 5 miles (8 km.) north of Brigham, Box- elder County, Utah (C. D. Walcott and L. D. Bui'ling, 1906). Obolus mcconnelli pelias. Eoorthis desmopleura. 54s (=5b). (For stratigraphic position and association, see p. 152.) Middle Cambrian: Dark blue-gray Langston limestone [Walcott, 1908f, p. 198], just above the Cambrian quartzitic sandstones, north side of Twomile Canyon, near its mouth, 2 miles (3.2 km.) southeast of Malade, Oneida County, Idaho (C. D. Walcott and L. D. Burling, 1906). *Micromitra haydeni (54s). Micromitra (Iphidella) pannula. *Micromitra (Iphidella) pannula maladensis (5b). Micromitra (Iphidella) pannula ophirensis. Lingulella desiderata. Lingulella helena. Lingulella isse. *Acrothele artemis (5b). Acrothele subsidua. Acrothele subsidua var. Acrotreta idahoensis sulcata. Acrotreta pyxidicula. Acrotreta?. *Acrothyra minor (5b). Billingsella coloradoensis. Hyolithes. Orthotheca. Stenotheca. Platyceras. Agnostus. Microdiscus. Solenopleura. Ptychoparia 2 sp. Oryctocephalus. Dorypyge 2 sp. Q Neolenus 2 sp. jg Asaphiscus. Ogygopsis?. 54t (=4y, 5a, 5c, 5e, and 54w). (For stratigraphic position and association, see p. 149.) Upper Cambrian: Lime- stone of the St. Charles limestone [Walcott, 1908a, p. 6], about 250 feet (76 m.) above the Middle Cambrian, on the north side of Twomile Canyon, near its mouth, 2 miles (3.2 km.) southeast of Malade, Oneida County, Idaho (C. D. Walcott and L. D. Burling, 1906). Obolus wortheni. Acrotreta idahoensis sulcata. Obolus (Westonia) ella. Billingsella coloradoensis. Lingulella desiderata. Ptychoparia. Acrotreta idahoensis. Anomocare. 54u. (For stratigraphic position and association, see p. 149.) Upper Cambrian: Limestone of the St. Charles lime- stone [Walcott, 1908a, p. 6], about 100 feet (30.5 m.) above the Middle Cambrian, on the north side of Two- mile Canyon, near its mouth, 2 miles (3.2 km.) southeast of Malade, Oneida County, Idaho (C. D. Walcott and L. D. Burling, 1906). *Obolus wortheni. Acrotreta idahoensis. Billingsella coloradoensit Agnostus. 54v. Ptychoparia 2 sp. Ptychaspis. Anomocare. (For stratigraphic position and association, see p. 150.) Middle Cambrian: Limestone in the lower part of the Bloomington formation [Walcott, 1908a, p. 7], about 1,600 feet (488 m.) below the Upper Cambrian, on the south side of Twomile Canyon, near its mouth, 2 miles (3.2 km.) southeast of Malade, Oneida County, Idaho (C. D. Walcott and L. D. Burling, 1906). Obolus wortheni. Ptychoparia 2 sp. 54w (=54t). (For stratigraphic position and association, see p. 149.) (C. D. Walcott and L. D. Burling, 1906.) Obolus tetonensis ninus. Obolus wortheni. Agnostus 2 sp. Ptychaspis. Ptychoparia 2 sp. Liostracus. Anomocare 3 sp. Damesella sp. LOCALITIES. 205 Six. (For stratigraphic position and association, see p. 149.) Upper Cambrian: St. Charlesi limestone [Walcott, 1908a, p. 6], about 200 feet (60.4 m.) above the Middle Cambrian, on the north side of Twomile Canyon, near its mouth, 2 miles (3.2 km.) southeast of Malade, Oneida County, Idaho (C. D. Walcott and L. D. Burling, 1906). Obolus wortheni. Billingsella coloradoensis Agnostus. Ptychoparia. 54y. Liostracus. Ptychaspis. Anomocare. Damesella. (For stratigraphic position and association, see p. 151.) Middle Cambrian: About 510 feet (155.4 m.) above the Brigham quartzite and 3,680 feet (1,121.7 m.) below the Upper Cambrian, in the limestone forming 2g of the Ute limestone [Walcott, 1908f, p. 197], in Blacksmith Fork Canyon, about 10 miles (16.1 km.) east of Hyrum, Cache County, Utah (C. D. Wale and L. D. Burling, 1906). Micromitra (Paterina) superba. Hyolithes. Ptychoparia. S5. (For stratigraphic position and association, see p. 140.) Middle Cambrian: Shaly limestone at the top of the Eldorado limestone [Walcott, 1908f, p. 184], east slope of Prospect Mountain, in New York Canyon, Eureka district [Hague, 1892, Atlas], Eureka County, Nev. (C. D. Walcott, 1886). Acrotreta definita. Billingsella whitfieldi. Agnostus bidens Meek. Agnostus tumidosus Hall and Whitfield. Dorypyge ? quadriceps (Hall and Whitfield). 55b. (For stratigraphic position and association, see p. 140.) Middle Cambrian: Top of the Eldorado limestone [Walcott, 1908f, p. 184], west side of Secret Canyon, Eureka district [Hague, 1892, Atlas], Eureka County, Nev. (C. D. Walcott, 1886). *Billingsella whitfieldi. *Orueia? eurekensis. Orusia lenticularis. Stenotheca elongata Walcott. Agnostus bidens Meek. Olenoides expansus (Walcott). Zacanthoides spinosus (Walcott). S5c (=163). (For stratigraphic position and association, see p. 152.) Middle Cambrian: Spence shale member of the Ute limestone [Walcott, 1908a, p. 8], about 50 feet (15.2 m.) above the Brigham quartzite and 2,755 feet (839.7 m.) below the Upper Cambrian, in a ravine running up into Danish Flat from Mill Canyon, about 6 miles (9.6 km.) west-southwest of Liberty and 15 miles (24.2 km.) west of Montpelier, Bear Lake County, Idaho (Mr. and Mrs. C. D. Walcott, Helen Walcott, Stuart Walcott, and L. D. Burling, 1906). Microdiscus sp. Olenoides, several species. *Zacanthoides idahoensis Walcott. Zacanthoides sp. Oryctocephalus reynoldsi Reed. Oryctocara geikiei Walcott. Ptychoparia, many species. Bathyuriscus howelli Walcott. Bathyuriscus productus (Hall and Whitfield). Bathyuriscus sp. Micromitra (Iphidella) pannula?- Obolus (Westonia) ella. Lingulella desiderata. Acrothele subsidua. Acrotreta definita. Acrotreta idahoensis sulcata. *Nisusia rara. Nisusia (Jamesella) spencei. Nisusia (Jamesella) nautes. Hyolithes. Agnostus, several species. 55d. (For stratigraphic position and association, see p. 150.) Middle Cambrian: About 2,000 feet (609.6 m.) above the Cambrian quartzitie beds, in a shale which is probably to be referred to the Bloomington forma- tion [Walcott, 1908a, p. 7], on the south side of Twomile Canyon, near its mouth, 2 miles (3.2 km.) south- east of Malade, Oneida County, Idaho (CD. Walcott, 1906). Obolus (Westonia) wasatchensis. 55e (=32p). (For stratigraphic position and association, see p. 152.) Middle Cambrian: Spence shale member of the Ute limestone, about 100 feet (30.5 m.) above the Brigham quartzite [Walcott, 1908f, p. 197], at the mouth of the first small canyon south of Wasatch Canyon, east of Lakeview Ranch, 5 miles (8 km.) north of Brigham, Boxelder County, Utah (C. D. Walcott and L. D. Burling, 1906). Micromitra (Iphidella) pannula. Obolus (Westonia) ella. Lingulella desiderata. Acrothele subsidua. Eocystites longidactylus Walcott. Agnostus. Ptychoparia piochensis Walcott. Zacanthoides idahoensis Walcott Neolenus 2 sp. Bathyuriscus howelli Walcott. Bathyuriscus productus (Hall and Whitfield). Ogygopsis. 206 CAJvIBRIAN BRACHIOPODA. 65h (=31m). (For stratigraphic position and association, see p. 149.) (C. D. Walcott, Stuart Walcott, and L. D. Burling, 1906.) Obolus. Agnostus. Lingulella. Ptychoparia. Billingsella coloradoensis. Anomocare. 55n (=31h). (For stratigraphic position and association, seep. 150.) Middle Cambrian: About 1,850 feet (564 m.> above the Brigham quartzite and 2,350 feet (716 m.) below the Upper Cambrian, in the limestone forming 2g of the Bloomington formation [Walcott, 1908f, p. 195], in Blacksmith Fork Canyon, about 10 miles (16.1 km.) east of Hyrum, Cache County, Utah (C. U. Walcott and L. D. Burling, 1906). Micromitra sculptilis. Ptychoparia. Dorypyge. 56t(^31z). (For stratigraphic position and association, see p. 151.) (F. B. Weeks, 1905.) Obolus (Westonia) ella. Acrothele subsidua?. Acrotreta ophirensis. 55u. (For stratigraphic position and association, see p. 158.) Middle Cambrian: Limestones about 200 feet (61 m.) above the Lower Cambrian [Walcott, 1908f, p. 171], 0.25 mile (0.4 km.) below the Maxfield mine, in Big Cottonwood Canyon, on the west front of the Wasatch Mountains, southeast of Salt Lake City, Salt Lake County, Utah (F. B. Weeks, 1905). Micromitra (Iphidella) pannula. *Linnarssonella urania. 56. (For stratigraphic position and association, see p. 139.) Upper? Cambrian: Limestone at Sierra Springs, eastern base of Lookout Moimtain, Eureka district [Hague, 1892, Atlas], Eureka County, Nev. (C. D. Walcott, 1880). Lingulella desiderata. Agnostus prolongus Hall and Whitfield. Agnostus tumidosus Hall and Whitfield. ■ 56a. Lower Cambrian: A limestone bowlder in the Sillery conglomerate on the south shore of St. Lawrence River, 4 miles (6.4 km.) below Quebec, Canada (C. D. Walcott, 1889). *Nisusia (Jamesella) amii. Olenellus? sp. Olenoides ellsi Walcott. 56b. Lower Cambrian: A liniestone bowlder in conglomerate on the south shore of the island of Orleans, below Quebec, Canada (C. D. Walcott, 1889). Obolella crassa. I Microdiscus connexus Walcott. Hyolithes americanus Billings. | Ptychoparia sp. 56c. (For stratigraphic position and association, see p. 147.) Lower Cambrian: Rome ("Montevallo") shale^ along road just north of Buck Creek, 1.125 miles (1.8 km.) northeast of Helena, Shelby County, Ala. (T. E. Williard, 1906). Ptychoparia cf. subcoronata (Hall and Whitfield). Ptychoparia sp. *Micromitra (Paterina) major. *Micromitra (Paterina) williardi *Obolus smithi. Wimanella shelbyensis. Psedeumias transitans Walcott. *Wanneria lialli Walcott. Agraulos?. Hyolithes. 56f. (For stratigraphic position and association, see p. 149.) Middle Cambrian: Nounan limestone [Walcott, 1908a, p. 6], on a ridge north of the creek which flows into Mill Canyon from the west, about 5 miles (8 km.), west-southwest of Liberty and 15 miles (24.2 km.) west of Montpelier, Bear Lake County, Idaho (C. D. Walcott and L. D. Burling, 1906). Obolus matinalis. Solenopleura. *Lingulella manticula var. Ptychoparia 2 sp. Orthotheca. Anomocare. Agraulos. Anomocarella. 56g. (For stratigraphic position and association, seep. 149). Upper Cambrian: Limestone of the St. Charles limestone [Walcott, 1908a, p. 6], in the valley of the stream which flows into Mill Canyon from the west, about 6 miles (9.6 km.) west-southwest of Liberty and 15 miles (24.2 km.) west of Montpelier, Bear Lake- County, Idaho (C. D. Walcott and L. D. Burling, 1906). Obolus discoideus. Platyceras. Acrotreta idahoensis. Agnostus. Billingsella coloradoensis. Ptychoparia. LOCALITIES. 207 56o. (For stratigraphic position and association, see p. 147.) Middle Cambrian: Limestone in upper third of Conasauga limestone, South Bessemer, Jefferson County, Ala. (T. E. Williard, 1906). Acrotreta (same one as in 56u). 56q. (For stratigraphic position and association, see p. 147.) Middle Cambrian: Limestone at the very top of the Conasauga limestone in quarry at Ketona, about 5 miles (8 km.) northeast of Birmingham, Jefferson County, Ala. (T. E. Williard, 1906). Lingulella quadrilateralis. Ptychoparia sp. 56u. (For stratigraphic position and association, see p. 147.) Middle Cambrian: Limestone in upper third of Conasauga limestone 700 feet (213.4 m.) southeast of Valley Creek bridge, near Nineteenth Street Road, Bessemer, Jefferson County, Ala. (T. E. Williard, 1906). Acrotreta (same one as in 56o). 57. (For stratigraphic position and association, see p. 140.) Middle Cambrian: Shaly limestone of the Eldorado • limestone [Walcott, 1908f, p. 184], at the 700-foot (213.4 m.) level of the Richmond mine, Ruby Hill [Hague, 1892, p. 43 and PL I, opposite p. 116], Eureka district, Eureka County, Nev. (C. D. Walcott, 1880). Lingulella desiderata. Lingulella punctata. Acrotreta definita. Agnostus bidens Meek. Agnostus richmondensis Walcott. Agnostus seclusus Walcott. 57b. (For stratigraphic position and association, see p. 140.) Middle Cambrian: Limestones at the north end of Mineral Hill, just south of Ruby Hill [Hague, 1892, p. 43, and PI. I, opposite p. 116], Eureka district, Eureka County, Nev. (C. D. Walcott, 1880). Lingulella desiderata. 57c (=57k). (For stratigraphic position and association, see p. 127.) Middle Cambrian: About 2,500 feet (762 m.) above the Lower Cambrian and 2,475 feet (754 m.) below the Upper Cambrian, in the limestone forming 1 of the Stephen formation [Walcott, 1908f, p. 209], on Mount Bosworth, north of the Canadian Pacific Rail- way between Hector and Stephen, on the Continental Divide between British Columbia and Alberta, Canada (C. D. Walcott and L. D. Burling, 1907). Micromitra zenobia. Ptychoparia 3 sp. Obolus mcconnelli. Menocephalus?. Nisusia alberta var. Neolenus sp. Hyolithes carinatus Matthew. Bathyuriscus?. 67d. (For stratigraphic position and association, see p. 125.) Upper Cambrian: About 3,215 feet (980 m.) above the Middle Cambrian and 375 feet(114.3 m.) below the top of the Upper Cambrian, o in green shales near the summit of 2b of the Sherbrooke limestone [Walcott, 1908f, p. 204], on ridge west of Mount Bosworth, on the Continental Divide between Alberta and British Columbia, Canada (C. D. Walcott and L. D. Burling, 1907). Lingulella isse. 57e. (For stratigraphic position and association, see p. 129.) Lower Cambrian: About 115 feet (35 m.) below the Middle Cambrian, in lime.stone correlated with the top of Ic of the Mount WTiyte formation on Mount Bosworth [Walcott, 1908f, p. 213], just above the tunnel on the north shoulder of Mount Stephen, about 3 miles (4.8 km.) east of Field, British Columbia, Canada (C. D. Walcott and L. D. Burling, 1907). Acrothele colleni. Acrotreta sagittalis taconica. Scenella varians Walcott. Stenotheca elongata Walcott. Albertella sp. Olenellus canadensis Walcott. Bathyuriscus sp. 57f. (For stratigraphic position and association, see p. 127.) Middle Cambrian: About 2,200 feet (670.5 m.) above the Lower Cambrian and 2,800 feet (853.4 m.) below the Upper Cambrian, in the limestone forming 1 of the Stephen formation [Walcott, 1908f, p. 209], about 0.5 mile (0.8 km.) east of the great "fossil bed" on the northwest slope of Mount Stephen, above Field on the Canadian Pacific Railway, British Columbia, Canada (C. D. Walcott and L. D. Burling, 1907). Obolus mcconnelli. Orthotheca sp. Acrotreta depressa. Scenella varians Walcott. Nisusia (Jamesella) cf. nautes. Ptychoparia sp. Hyolithes carinatus Matthew. a See tlie footnote on page 125. 208 CAMBRIAN BRACHIOPODA. 57g. (For stratigraphic position and association, see p. 128.) Middle Cambrian: About 1,700 feet (518 m.) above the Lower Cambrian and 3,250 feet (991 m.) below the Upper Cambrian, in the siliceous shales forming 2d of the Stephen formation [Walcott, 1908f, p. 211], on Mount Bosworth, north of the Canadian Pacific Railway between Hector and Stephen, on the Continental Divide between British Columbia and Alberta, Canada (C. D. Walcott and L. D, Burling, 1907). Micromitra (Iphidella) pannula. Obolus (Westonia) ella. Cruziana. Hyolithes. Leperditia. Ptychoparia. Bathyuriscus. 57j. (For stratigraphic position and association, see p. 127.) Middle Cambrian: About 2,000 feet (609.6 m.) above the Lower Cambrian, in the limestone forming 2 of the Stephen formation [Walcott, 1908c, p. 237 (6)], just east of the "fossil bed" on the northwest slope of Mount Stephen, above Field on the Canadian Pacific Railway, British Columbia, Canada (C. D. Walcott and L. D. Burling, 1907). Micromitra (Iphidella) parmula. Nisusia alberta var. Hyolithes. Bathyiiriscus rotundatus (Rominger). Neolenus serratus (Rominger). 57k (=57c). (For stratigraphic position and association, see p. 127.) (C. D. Walcott and L. D. Burling, 1907.) Obolus mcconnelli. Nisusia alberta var. Agnostus. Agraulos. Ptychoparia. Neolenus. 57ni. (For stratigraphic position and association, see p. 129.) Lower Cambrian: About 50 feet (15 m.) below the Middle Cambrian, in a siliceous shale correlated with lb of the Mount Whyte formation on Mount Bosworth [Walcott, 1908f, p. 213], just above the tunnel on the north shoulder of Mount Stephen, about 3 miles (4.8 km.) east of Field, British Columbia, Canada (C. D. Walcott and L. D. Burling, 1907). Micromitra (Paterina) sp. Acrotreta sagittalis taconica. Nisusia (Jamesella) lowi. Cystid plates. Scenella varians Walcott. Hyolithes. Hyolithellus cf. micans (Billings). Olenellus canadensis Walcott. 57n. (For stratigraphic position and association, see p. 127.) Middle Cambrian: About 3,000 feet (914.4 m.) above the Lower Cambrian and about 700 feet (213.4 m.) above the base of a limestone correlated with 4 of the Eldon limestone on Mount Bosworth [Walcott, 1908f, p. 209], on the northwest slope of Mount Stephen, above Field on the Canadian Pacific Railway, British Columbia (C. D. Walcott and L. D. Burling, 1907). Lingulella cf. isse. Protospongia (spicules) . Hyolithes. Agnostus cf . mentis Matthew. Zacanthoides spinosus (Walcott). Ptychoparia. Bathyuriscus. Ogygopsis. 57r (=58s). (For stratigraphic position and association, see p. 129.) (L. D. Burling, 1907.) Micromitra (Paterina) labradorica var. | Acrotreta sagittalis taconica. Micromitra (Iphidella) pannula. | Ptychoparia 3 sp. 57s. (For stratigraphic position and association, see p. 129.) Lower Cambrian: About 160 feet (49 m.) below the Middle Cambrian, near the base of the gray oolitic limestone forming lb of the Mount Whyte formation [Walcott, 1908f, p. 212], on Mount Bosworth, north of the Canadian Pacific Railway between Hector and Stephen, on the Continental Divide between British Columbia and Alberta, Canada (C. D. Walcott, 1907). Nisusia (Jamesella) lowi. Acrotreta sagittalis taconica. Microdiscus?. Agraulos sp. Ptychoparia sp. 57y. (For stratigraphic position and association, see p. 128.) Middle Cambrian: About 1,900 feet (579 m.) above the Lower Cambrian and 3,050 feet (930 m.) below the Upper Cambrian, in the siliceous shales forming 2a of the Stephen formation [Walcott, 1908f, p. 211], on Mount Bosworth, north of the Canadian Pacific Railway between Hector and Stephen, on the Continental Divide between British Columbia and Alberta, Canada (C. D. Walcott and L. D. Burling, 1907). Obolus (Westonia) ella?. LOCALITIES. 209 58. (For stratigraphic position and association, see p. of Secret Canyon shale, east side of New York Eureka County, Nev. (C. D. Walcott, 1880). Micromitra sculptilis. Micromitra (Paterina) crenistria?. Obelus discoideus. Obelus masra. Obolus mcconnelli. Obolus nundina. *Obolus (Acritis) rugatus. *Lingulella clarkei. Lingulella desiderata. *Lingulella punctata. *Acrotliele dichotoma. *Acrotreta idahoensis alta. Acrotreta microscopica. 139.) Middle Cambrian: Shaly limestones m upper beds and Secret canyons, Eureka district [Hague, 1892, Atlas], Protospongia fenestrata Salter. Hyolithes primordialis Hall. Agnostus bidens Meek. Agnostus communis Hall and '^Tiitfield. Agnostus neon Hall and "\Miitfield. *Agnostus seclusus Walcott. Agnostus tumidosus Hall and WTiitfield. Ptychoparia anytus (Hall and ^Miitfield). Ptychoparia haguei (Hall and ^Miitfield). *Ptychoparia laeviceps Walcott. Ptychoparia? linnarssoni Walcott. Ptychoparia unisulcatus (Hall and 'VMiitfield). Ogygia? problematica Walcott. 58f. (For stratigraphic position and association, seep. 125.) ITpper Cambrian: About 3,100 feet (945 m.) above the Middle Cambrian, in the limestone interbedded in the shales forming 2b of the Sherbrooke limestone [Walcott, 1908f, p. 204], ridge west of Mount Bosworth, on the Continental Divide between Alberta and British Columbia, Canada (C. D. Walcott and L. D. Burling, 1907). Obolus sp. 58i. (For stratigraphic position and association, seep. 127.) Middle Cambrian: About 1,225 feet (373 m.) above the Lower Cambrian, in the shales of the Stephen formation [Walcott, 1908a, p. 3], northeast slope of Castle Mounta,in, facing the amphitheater north of the Canadian Pacific Railway, Alberta, Canada (C. D. Walcott and L. D. Burling, 1907). Obolus mcconnelli. 58j. (For stratigraphic position and association, seep. 127.) Middle Cambrian: About 1,900 feet (579 m.) above the Lower Cambrian and 3,100 feet (945 m.) below the Upper Cambrian, near the base of the limestone forming 2 of the Stephen formation [Walcott, 1908c, p. 238 (7)], on the east side of Mount Stephen, about 3,000 feet (914 m.) above the Canadian Pacific Railway track 3 miles (4.8 km.) east of Field, British Columbia (CD. Walcott and L. D. Burling, 1907). Micromitra (Iphidella) pannula. Obolus mcconnelli. Acrothele subsidua. Acrotreta depressa. Hyolithes sp. Agnostus montis Matthew. Agraulos sp. Ptychoparia sp. Zacanthoides sp. Bathj'uriscus sp. Albertella sp. 58k (same horizon as 58p). (For stratigraphic position and association, see p. 129.) Lower Cambrian: Just below the Middle Cambrian, in limestones forming 1 of the Mount Whyte formation [^'alcott, 1908c, p. 240 (9)], just above the tunnel on the north shoulder of Mount Stephen, about 3 miles (4.8 km.) east of Field, British Columbia, Canada (C. D. Walcott and L. D. Burling, 1907). Acrotreta sagittalis taconica. Nisusia alberta var. *Nisusia (Jamesella) lowi. Stenotheca elongata Walcott. Scenella varians Walcott. Platyceras sp. Hyolithes billingsi Walcott. Ptychoparia sp. Crepicephalus sp. Protypus sp. Albertella sp. 581. (For stratigraphic position and association, see p. 128.) Middle Cambrian: About 1,830 feet (557.8 m.) above the Lower Cambrian, in the limestone forming 3b of the Stephen formation [Walcott, 1908c, p. 238 (7)], on the east side of Mount Stephen, about 3,000 feet (914.4 m.) above the Canadian Pacific Railway track,'3.5 miles (5.6 km.) east of Field, British Columbia (C. D. Walcott and Mr. and Mrs. L. D. Burling, 1907). Micromitra zenobia Lingulella desiderata. * Billingsella marion. 62667°— VOL 51, pt 1 Hyolithes sp. Microdiscus sp. Ptychoparia sp. -12- -14 210 CAJMBRIAN BRACHIOPODA. 68p (same horizon as 58k). (For stratigraphic position and association, see p. 129.) Lower Cambrian: Drift block of limestone believed to have come from the limestone forming 1 of the Mount Whyte formation fW'alcott, 1908c, p. 240 (9)], found near the Canadian Pacific Railway track just west of the tunnel, 3 miles (4.8 km.) eaft of Field, British Columbia, Canada (C. D. Walcott and L. D. Burling, 1907). Nisusia alberta var. I Hyolithes billingsi Walcott. Nisusia (Jamesella) lowi. I Ptychoparia. 58r. (For stratigraphic position and association, see p. 127.) Middle Cambrian: About 1,800 feet (548.6 m.) above the Lower Cambrian and 3,200 feet (975.4 m.) below the Upper Cambrian, in the limestones forming 2 of the Stephen formation [Walcott, 1908f, p. 211], in the amphitheater between Mounts Stephen and Dennis, above Field on the Canadian Pacific Railway, British Columbia, Canada (C. D. Walcott and L. D. Burling, 1907). Ptychoparia. Neolenus serratus (Rominger). Ogygopsis klotzi (Rominger). Obolus mcconnelli. Acrotreta depressa. Hyolithellus annulatus (Matthew) 68s (=57r). (For stratigraphic position and association, see p. 129.) Lower Cambrian: About 150 feet (46 m.) below the Middle Cambrian, near the base of the limestones forming 3 of the Mount Whyte formation [Wal- cott, 1908c, p. 241 (10)], just above the tunnel on the north shoulder of Mount Stephen, about 3 miles (4.8 km.) east of Field, British Columbia, Canada (C. D. Walcott and L. D. Burling, 1907). Micromitra (Paterina) labradorica var. 1 Acrotreta sagittalis taconica. Micromitra (Iphidella) pannula. j Ptychoparia 3 sp. 58t. (For stratigraphic position and association, see p. 129.) Lower Cambrian: Sandy shale about 150 feet (45.7 m.) below the Middle Cambrian, just below the big cliff on the east shoulder of Castle Mountain, north of the Canadian Pacific Railway, Alberta, Canada (L. D. Burling and Stuart Walcott, 1907). Obolus parvus. 58w. (For stratigraphic position and association, see p. 127.) Middle Cambrian: About 1,300 feet (396 m.) above the Lower Cambrian, in the shales of the Stephen formation [Walcott, 1908a, p. 3], northeast slope of Castle Mountain, facing the amphitheater north of the Canadian Pacific Railway, Alberta, Canada (C. D. Wal- cott and L. D. Burling, 1907). Obolus mcconnelli. 68z. (For stratigraphic position and association, seep. 128.) Middle Cambrian: About 1,875 feet (572 m.) above the Lower Cambrian and 3,100 feet (945 m.) below the Upper Cambrian, in the limestone forming 2b of the Stephen formation [\\^alcott, 1908f, p. 211], on Mount Bosworth, north of the Canadian Pacific Railway between Hector and Stephen, on the Continental Divide between British Columbia and Alberta, Canada (C. D. Walcott and L. D. Burling, 1907). Micromitra zenobia. Ptychoparia. Nisusia alberta var. Neolenus. Menocephalus. 59. (For stratigraphic position and association, see p. 140.) Middle Cambrian: Limestone at the base of the western •slope of Combs Peak, near the plain of Antelope Valley, Eureka district [Hague, 1892, Atlas], Eureka County, Nev. (C. D. Walcott, 1880). Lingulella arguta. I Agnostus tumidosus Hall and Whitfield. Acrotreta attenuata. | Dorypyge ? quadriceps (Hall and Whitfield). 59f. (For stratigraphic position and association, seep. 152.) -Middle Cambrian; Limestones immediately under- lying the Spence shale member of the Ute limestone [Walcott, 1908a, p. 8], ir a saddle north of the creek which flows into Mill Canyon from the west, about 5 miles (8 km.) west-southwest of Liberty and 15 miles (24.2 km.) west of Montpeiier, Bear Lake County, Idaho (C. D. Walcott, jr., and L. D. Burling, 1907). Micromitra (Iphidella) pannula, Lingulella desiderata. Acrotreta pyxidicula, Solenopleura sp. Neolenus sp. Anomocare sp. Ptychoparia sp. Agraulos sp. Stenotheca sp. Zacanthoides sp. 59g. (For stratigraphic position and association, see p. 151.) Middle Cambrian: Limestones immediately over- lying the Spence shale member of the Ute limestone [Walcott, 1908a, p. 8], in a saddle north of the creek which flows into Mill Canyon from the west, about 5 miles (8 km.) west-southwest of Liberty and 15 miles (24.2 km.) west of Liberty, Bear Lake County, Idaho (C. D. Walcott, jr., and L. D. Burling, 1907). Lingulella sp. Neolenus. Acrothele subsidua. Microdiscus. Acrotreta cf . idahoensis. Zacanthoides idahoensis Walcott. Ptychoparia 3 sp. Menocephalus. LOCALITIES. 211 59m. (For stratigraphic position and association, see p. 147.) Lower Cambrian: Weisner quartzite in the Roan iron mine, Bartow County, Ga. (S. W. McCallie, 1900). Obolella cf . atlantica. Obolella cf . crassa. Archseocyathus?. Stenotheca cf. rugosa (Hall). Olenellus thompsoni (Hall). 60. (For stratigraphic position and association, see p. 139.) Middle Cambrian: Limestones in upper beds of Secret Canyon shale, across the canyon from the dump of the old Richmond mine shaft. Eureka district [Hague, 1892, Atlas], Eureka County, Nev. (C. D. Walcott, 18801 Agnostus prolongus Hall and Whitfield. Ptychoparia maculosa (Hall and 'Whitfield). Ptychoparia unisulcata (Hall and "WTiitfield). Lingulella clarkei. Lingulella desiderata. Lingulella sp. Acrotreta pyxidicula. I 60b. (For stratigraphic position and association, seep. 130.) Lower Cambrian: About 2,300 feet (702 m.) below the Mount Why te formation and 200 to 300 feet (61 to 92 m.) above the Lake Louise shale, in the St, Piran sand- stone [Walcott, 1908a, p. 4], at Vermilion Pass, on the Continental Divide between British Columbia and Alberta, west-southwest of Castle on the Canadian Pacific Railway, Alberta, Canada (C. T). Walcott, 1909). * Obolella vermilionensis. Wanneria gracile Walcott. 61. (For stratigraphic position and association, seep. 139.) Upper Cambrian: Limestone in the Dunderberg shale [Walcott, 1908f, p. 184], a little south of the Hamljurg mine, Eureka district [Hague, 1892, Atlas], Eureka County, Nev. (C. D. Walcott and C. H. H., 1882). Acrotreta idahoensis alta. *Acrotreta spinosa. Acrotreta sp. Agnostus prolongus Hall and Whitfield. Agnostus tumidosus Hall and Whitfield. Ptychoparia granulosa (Hall and Whitfield). Ptychoparia maculosa (Hall and Whitfield). Ptychoparia unisulcata (Hall and Whitfield). Micromitra sculptilis. Obelus anceps. Obolus msera. Obolus nundina. Lingulella desiderata. Lingulella manticula. Lingulella punctata. Acrotreta attenuata. Acrotreta idahoensis. 62. (For stratigraphic position and association, see p. 139.) Upper Cambrian: Limestone in the Dunderberg shale [Walcott, 1908f, p. 184], in canyon immediately north of Adams Hill, Eureka district [Hague, 1892. Atlas], Eureka County, Nev. (C. D. Walcott, 1880). Micromitra sculptilis. Obolus discoideus. Lingulella manticula. Lingulella punctata. Acrotreta spinosa. Agnostus prolongus Hall and Whitfield. Ptychoparia breviceps (Walcott). Arethusina americana Walcott. 62a. (For stratigraphic position and association, seep. 139.) Upper Cambrian: Limestone on east side of Sierra Canyon, opposite the Jackson mine. Eureka district [Hague, 1892, Atlas], Eureka County, Nev. (C. D. Walcott, 1880). Acrotreta spinosa. Ptychoparia granulosa (Hall and Whitfield). Ptychoparia simulator (Hall and Whitfield). 63. (For stratigraphic position and association, seep. 139.) Lower Ordovician: At the base of the Pogonip lime- stone northeast of Adams Hill, Eureka district [Hague, 1892, Atlas], Eureka County, Nev. (C. D. Walcott, 1880). ^ *Obolus anceps. *Elkania ambigua. Acrotreta idahoensis alta. Schizambon?. Syntrophia nundina. 64. (For stratigraphic position and association, seep. 139.) ITpper Cambrian: Limestone near the Bullwhacker mine. Eureka district [Hague, 1892, Atlas], Eureka County, Nev. (C. D. Walcott, 1880). Obolus discoideus. Obolus (Westonia) iphis. Agnostus prolongus Hall and Whitfield. 65. (For stratigraphic position and association, seep. 139.) Upper Cambrian: Limestone on the east side of Sierra Canyon, opposite Pinnacle Peak, Eureka district [Hague, 1892, Atlas], Eureka County, Nev. (Arnold Hague and J. P. Iddings, 1880). Acrotreta idahoensis alta. Acrotreta spinosr.. 212 CAMBKIAN BEACHIOPODA. 66. (For stratigraphic position and association, see p. 139.) Upper Cambrian; Dunderberg shale fWalcott, 1908f, p. 184], on the first ridge north of the Dunderberg mine, Eureka district [Hague, 1892, Atlas], Eureka County, Nev. (C. D. Walcott, 1880). Obolus discoideus. Agnostus prolongus Hall and Whitfield. Arethusina americana Walcott. 67 (=67c). Upper Cambrian: Sandstone on Tatur Hill, 7 miles (11.2 km.) northwest of Burnet, Burnet County, Tex. (C. D. Walcott, 1884). Obolus matinalis. Obolus sinoe. Lingulella acutangula. Acrotreta microscopica. Ptychoparia affinis (Walcott). Ptychoparia diademata (Hall). 67c (=67). Obolus matinalis. Lingulella acutangula. Lingulella perattenuata. Ptychoparia llanoensis Walcott. Ptychoparia? metra Walcott. Ptychoparia? urania Walcott. Ptychoparia wisconsinensis (Owen) Anomocare pero (Walcott). 67z. Upper Cambrian: Sandstone at west base of Tatur Hill, 7 miles (11.2 km.) northwest of Burnet, Burnet County, Tex. (C. D. Walcott, 1884). Obolus matinalis. Ptychoparia burnetensis Walcott. 68 (=68e, 68y, and 68z). Upper Cambrian: Interbedded sandstone and limestone, Packsaddle Mountain, Llano County, Tex. (C. D. Walcott, 1884). Obolus matinalis. Obolus tetonensis ninus. Lingulella acutangula. Acrotreta microscopica. Billingsella coloradoensis. Eoorthis indianola?. Eoorthis remnicha texana. Eoorthis wichitaensis. Eoorthis wichitaensis Iseviusculus. *Huenella texana. Platyceras texanum Walcott. Ptychoparia affinis (Walcott). Ptychoparia diademata (Hall). Ptychoparia llanoensis Walcott. Ptychoparia similis Walcott. Ptychoparia? urania Walcott. Agraulos convexus Whitfield. Anomocare pero (Walcott). Chariocephalus sp. 68e (=68). Lingulella acutangula. Acrotreta microscopica. Billingsella coloradoensis. 68y(=68). Obolus sinoe. Lingulella perattenuata. 68z (=68). Obolus matinalis. 69. Upper Cambrian: Limestone near Honey Creek, Burnet County, Tex. (C. D. Walcott, 1884). Obolus sinoe. Lingulella acutangula. Lingulella texana. Lingulella (Lingulepis) acuminata. Acrotreta microscopica. Billingsella coloradoensis. *Syntrophia alata. Huenella texana. Huenella texana laeviuBculus. Capulus sp. Ptychoparia affinis (Walcott). Ptychoparia diademata (Hall). Ptychoparia llanoensis Walcott. Anomocare pero (Walcott). Pterocephalia sancti-sabse Roemer. Chariocephalus tumifrons Hall and Whitfield. LOCALITIES. 213 70(=70aand 70e). Upper Cambrian: Limestone near Obolus since. Lingulella acutangula. Lingulella perattenuata. *Lingulella texana. Lingulella (Lingulepia) acuminata. Billingsella coloradoensis. Capulus?. Cystidean plates. Ptychoparia diademata (Hall) Ptychoparia pattersoni Hall. 70a (=70). Billingsella coloradoensis. Illsenurus? dia Walcott. Ptychoparia occidens Walcott. Morgans Creek, Burnet County, Tex. (C. D. Walcott, 1884). Ptychoparia perseus Hall var. Ptychoparia romerei (Shumard). Ptychoparia suada Walcott. Ptychoparia wisconsinensis (Owen). Agraulos convexus Whitfield. Anomocare pero (Walcott). Pterocephalia sancti-sabse Roemer. Chariocephalus tumifrons Hall and Whitfield. PtychaspLs granulosa (Owen). Ptychoparia wisconsinensis (Owen). Dikellocephalus belli Billings. Dikellocephalus minnesotensis Owen. 70e (=70). Lingulella acutangula. *Acrotreta microscopica. Billingsella coloradoensis. 71. Upper Cambrian: Limestone in Cold Creek Canyon, Burnet County, Tex. (C. D. Walcott, 1884). Obolus matinalis. Obolus sinoe. Acrotreta microscopica. Billingsella coloradoensis. Eoorthis iddingsi. Eoorthis indianola. *Eoorthis remnicha texana. Eoorthis wichitaensis. Huenella texana. *Huenella texana laeviusculus. Ptychoparia affinis (Walcott). Ptychoparia wisconsinensis (Owen). Agraulos convexus Whitfield. Anomocare pero (Walcott). 72 (same horizon as 72a). Lower Cambrian: Limestone 5 miles (8 km.) east of Albany, Rensselaer County, N. Y. (C. D. Walcott and T. N. Dale, 1893). Obolus prindlei. 72a (same horizon as 72). Lower Cambrian: Limestone 1 mile (1.6 km.) southwest of Wynantskill, Rensselaer County, N. Y. (L. M. Prindle, 1893). *Obolus prindlei. 73. Middle Cambrian: Sandstones of the Tonto group in Kwagunt Valley, Grand Canyon of the Colorado, Ariz. (CD. Walcott, 1882). Obolus (Westonia) chuarensis. *Lingulella lineolata. 73a. Middle Cambrian: "Tonto" sandstone in Chuar Valley, Grand Canyon of the Colorado, Ariz. (C. D. Wal- cott, 1882). *Micromitra (Paterina) superba. 1 *Obolus (Westonia) chuarensis. Micromitra (Iphidella) pannula. | Lingulella lineolata. 73b. Middle Cambrian: Sandstone in upper part of the Tonto group, lower portion of Kwagunt Valley, Grand Canyon of the Colorado, Ariz. (C. D. Walcott, 1882). Micromitra (Paterina) crenistria. 74. Middle Cambrian: Sandstone about 300 feet (91.4 m.) above the base of the Tonto group at the head of Nunkoweap Valley, Grand Canyon of the Colorado, Ariz. (C. D. Walcott, 1882). Micromitra pealei. *Micromitra (Paterina) crenistria. Micromitra (Paterina) superba. Micromitra (Iphidella) pannula. *Obolus zetus. Obolus (Westonia) chuarensis. *Obolus (Westonia) euglyphus. Lingulella lineolata. Lingulella perattenuata. *Billingsella obscura. 74b. Middle Cambrian: Sandstone 1,000 feet (305 m.) above the base of the Tonto group, Nunkoweap Valley, Grand Canyon of the Colorado, Ariz. (C. D. Walcott). Obolus (Westonia) chuarensis. 214 CAMBRIAN BRACHIOPODA. 74c. Middle Cambrian: "Tonto" sandstone at the head of Lava Canyon, Grand Canyon of the Colorado, Ariz. (C. D. Walcott, 1883). Obelus (Westonia) euglyphus. 74d. Middle Cambrian: Sandstone beds in "Tonto" shale just above massive sandstones, near mouth of Bass Canyon, on the south side of the Grand Canyon of the Colorado, southeast of Powells Plateau, Ariz. (C. D. Walcott, 1901). Micromitra (Paterina) superba. Micromitra (Iphidella) pannula. Linarulella lineolata. Lingulella perattenuata. *Lingulella (Lingulepis) spatula. 75. Upper Cambrian: Thin-bedded limestones below the base of the Ordo^dcian in the Tonto group, near the water's edge at the mouth of Kanab Canyon, Grand Canyon of the Colorado, Ariz. (C. D. Walcott, 1879). Obolus zetus. Lingulella winona convexa. *Nisusia? (Jamesella?) kanabensis.l _, . . , , , *Protorthis sp. undt. ) ^^®^® species may not occur m the same bed. 76. Upper Cambrian: Arenaceous limestone at Hoyt's quarry, 4 miles (6.4 km.) west of Saratoga Springs, Sara- toga County, N. Y. (C. D. Walcott and Cooper Curtice, 1883). Lingulella (Lingulepis) acuminata. Dikellocephalus. 76a. Upper Cambrian: Arenaceous limestone in a railroad quarry 1 mile (1.6 km.) north of Saratoga Springs, Saratoga County, N. Y. (C. D. Walcott and Cooper Curtice, 1883). Lingulella (Lingulepis) acuminata. 77. Upper Cambrian: Sandstone near the water below the falls at the high bridge, and also at several horizons in the section, the highest point being 70 to 75 feet (21 to 22 m.) above the water, in Ausable Chasm, Essex County, N. Y. (C. D. Walcott and Cooper Curtice, 1883 and 1886). *Lingulella prima. Lingulella (Lingulepis) acuminata. 78 (=78s). Upper Cambrian: "St. Croix sandstone," quarry near St. Croix River, in suburbs of Osceola, Polk County, Wis. (L. C. Wooster, 1883). Obolus (Westonia) aurora. Lingulella mosia. *Lingulella mosia osceola. Lingulella winona. *Lingulella winona convexa. Billingsella coloradoensis. Finkelnburgia finkelnburgi. *Pinkelnburgia osceola. *Finkelnburgia osceola corrugata. Syntrophia barabuensis. Ulaenurus quadratus Hall . Spirodentalium osceola Walcott. Bellerophon antiquatus Whitfield. 78a. Upper Cambrian: "St. Croix sandstone" in the topmost quarry on Mount Washington, near Eau Claire, Eau Claire County, Wis. (L. C Wooster, 1883). *Agraulos? thea Walcott. Crepicephalus iowensis (Hall). Obolus sp. undt. Dicellomus pectenoides. Dicellomus politus. 78b. Upper Cambrian: "St. Croix sandstone" 50 feet (15.2 m.) above St. Croix River, near the landing at Osceola, Polk County, Wis. (Cooper Curtice, 1884). Lingulella mosia. Lingulella similis. Finkelnburgia osceola. 78c. Upper Cambrian: "St. Croix sandstone" at Osceola, Polk County, Wis. (C. Schuchert, 1893). Obolus (Westonia) aurora. 1 Lingulella winona. Lingulella oweni. I Lingulella winona convexa. 78d. Upper Cambrian: The upper portion of the "St, Croix sandstone" exposed in the bluffs at La Crosse, La Crosse County, Wis. (C. D. Walcott, 1898). Obolus matinalis. 78s (=78). (C. Schuchert, 1893.) Obolus (Westonia) aurora. Lingulella mosia. Lingulella mosia osceola. Lingulella winona convexa. Finkelnburgia finkelnburgi. Finkelnburgia osceola. Finkelnburgia osceola corrugata. LOCALITIES. 215 79. Upper Cambrian: "St. Croix sandstone" in bluff near Hudson, St. Croix County, Wis. (L. C. Woos'-er, 1883). Obolus matinalis. *Obolus mickwitzi. Obolus (Westonia) aurora. Lingulella mosia. Lingulella winona. Lingulella winona convexa. Lingulella (Lingulepis) acuminata. Billingsella coloradoensis. Ptychoparia Wisconsin ensis (Owen) 79' (=79, though from a slightly different horizon). (Chas. Schuchert, 1893.) Obolus matinalis. Obolus mickwitzi. 79a. Upper Cambrian: "St. Croix sandstone," quarry and ledge 0.5 mile (0.-" km.) southeast of the county courthouse, Menomonie, Dunn County, Wis. (L. C. Wooster, 1883). Lingulella winona convexa. *Protorthis laevis. Billingsella coloradoensis. Eoorthis sp. Finkelnburgia osceola. 79b. Upper Cambrian: "St. Croix sandstone" in shaly beds 4 feet (1.2 m.) above the water, near Hudson, St. Croix County, Wis. (J. F. James, 1889). Obolus matinalis. I Lingulella (Lingulepis) acuminata. Obolus mickwitzi. | Finkelnburgia osceola. 79s. Upper Cambrian: "St. Croix sandstone" in bluff near Hudson, St. Croix County, Wis. (C. Schuchert, 1893). Lingulella mosia. Dicellomus politus. 79x. Middle Cambrian: "St. Croix sandstone" near the fiour mill on Beaver Creek, north of Galesville, Trem- pealeau County, Wis. (Cooper Curtice, 1882; L. C. Wooster, 1883). (See p. 159.) Lingulella (Lingulepis) acuminata. Dicellomus politus. 80. Upper Cambrian: "St. Croix sandstone" 0.66 mile (1.1 km.) southwest of the railway depot, Menomonie, Dunn County, Wis. (L. C. Wooster, 1883). Lingulella ampla. I Dicellomus politus. Lingulella winona convexa. | Finkelnburgia osceola. 80a. Upper Cambrian: "St. Croix sandstone" 4 miles (6.4 km.) north of Reedsburg, Sauk County, Wis. (L. C. Wooster, 1883). Lingulella similis. Billingsella coloradoensis. *Eoorthis remnicha. Eoorthis remnicha sulcata. Finkelnbm-gia osceola. 81. Upper Cambrian: "St. Croix sandstone" 1 mile (1.6 km.) east-northeast of Devils Lake, Sauk County, Wis. (L. C. Wooster, 1883). Finkelnbiurgia finkelnburgi. . 81b. Upper Cambrian: "St. Croix sandstone" near Devils Lake, Sauk County, Wis. (Cooper Curtice, 1884). Obolus (Westonia) stoneanus. I Finkelnburgia finkelnburgi. *Eoorthis diablo. I Syntrophia barabuensis. 81o. Upper Cambrian: "St. Croix sandstone" on the railroad track below the Cliff House, Devils Lake, Sauk County, Wis. (J. F. James, 1889). Syntrophia barabuensis. 82 (see 82s). Upper Cambrian: "St. Croix sandstone" on the bank of St. Croix River, at St. Croix Falls, Polls: County, Wis. (L. C. Wooster, 1883). Lingulella (Lingulepis) acuminata. 82a. Upper Cambrian: "St. Croix sandstone" 25 feet (7.6 m.) above the water level, near the Knapp, Stout and Company's buildings, Menomonie, Dunn County, Wis. Obolus matinalis. Lingulella phaon. 82b (see 339d; may be same locality). Upper Cambrian: "St, Croix sandstone" along the railroad track near Taylors Falls, Chisago County, Minn. (W. A. Finkelnburg). *Curticia elegantula. Obolus matinalis. Dicellomus politus 216 CAMBRIAN BEACHIOPODA. 82c. Upper Cambrian: Conglomerate beds in the "St. Croix sandstone " in point below Franconia, Chisago County, Minn. (W. A. Finkelnburg). Lingulella similis. 82s (see 82). Upper Cambrian: "St. Croix sandstone" on the bank of St. Croix River, St. Croix Falls, Polk County, Wis. (C. Schuchert, 1893). Obolus matinalis. Lingulella (Lingulepis) acuminata. 83. Upper Cambrian: "St. Croix sandstone" near Trempealeau, Trempealeau County, Wis. (Cooper Curtice and G. H. Squiers, 1884). Finkelnburgia osceola. Syntrophia barabuensis. Chariocephalus whitfieldi Hall. Obolus matinalis. Dicellomus politus. Eoorthis diablo. *Finkelnburgia finkelnburgi. 83' ( = 135c). (Chas. Schuchert, 1893.) Billingsella coloradoensis. Finkelnburgia finkelnburgi. Finkelnburgia osceola. 83^ Upper Cambrian: Green-sand horizon in the "St. Croix sandstone," below the "fifth trilobite bed" of Owen, at Trempealeau, Trempealeau County, Wis. (Chas. Schuchert, 1893). Billingsella coloradoensis. Chariocephalus whitfieldi Hall. 83*. Middle Cambrian: "St. Croix sandstone," in beds characterized by the presence of Crepicephalus iowensis, at Trempealeau, Trempealeau County, W^s. (C. Schuchert, 1893). (See p. 159.) Obolus matinalis. 84. Middle Cambrian: "St. Croix sandstone" at Dresbach, opposite the mouth of Black River, Winona County, Minn. (Cooper Curtice, 1884). (See p. 159.) Obolus namouna. Obolus rhea. Lingulella ampla. Lingulella (Lingulepis) acuminata. Dicellomus politus. 84;a. Upper Cambrian: "St. Croix sandstone," River Junction, Houston County, 20 miles i'32.2 km.) below Dresbach, Minn. (Cooper Curtice, 1884). Dikellocephalus misa Hall. ■ Chariocephalus whitfieldi Hall. Lingulella phaon.a Billingsella coloradoensis. Syntrophia primordialis. 84i. Middle Cambrian: "St. Croix sandstone" at Dresbach, opposite the mouth of Black River, Winona County, Minn. (W. A. Finkelnburg, 1897). (See p. 159.) Lingulella ampla. . Dicellomus politus. 84s. Middle Cambrian: "St. Croix sandstone" near Dakota, Winona County, Minn. (Chas. Schuchert, 1893). (See p. 159.) Lingulella ampla. Lingulella ( Lingulepis) acuminata. Dicellomus politus. 85 (=803). Upper Cambrian: "St. Croix sandstone" at Prairie du Sac, Sauk County, Wis. (Cooper Curtice, 1884). Obolus (Westonia) stoneanus. *Lingulella mosia. 85a. LTpper Cambrian: "St. Croix sandstone" at Brown's quarry, Prairie du Sac, Sauk County, Wis. (Cooper Curtice, 1884). Lingulella oweni. 85s (=85, though possibly from a slightly different bed). Upper Cambrian: "St. Croix sandstone" at Prairie du Sac, Sauk County, Wis. (Chas. Schuchert, 1893). Obolus (Westonia) aurora. *Obolus (Westonia) stoneanuB. Lingulella mosia. Lingulella oweni. Lingulella winona. Lingulella winona convexa. Illsenurus quadratus Hall. Dikellocephalus minnesotensis Owen. Dikellocephalus pepinensis Owen. a May be from a horizon different from tliat of the other species. LOCALITIES. 217 85x. Upper Cambrian: Upper beds of the "St. Croix sandstone" near Mazomanie, Dane Comity, Wis. (Chas. Schuchert, 1893). Obolus (Westonia) stoneanus. Lingulella mosia. Lingulella winona. Lingulella winona convexa. Finkelnburgia osceola. Dikellocephalus sp. S85x (=8ox, though possibly from a slightly different bed). *Obolus (Westonia) aurora. Lingulella mosia. Lingulella winona convexa. 85z. Upper Cambrian: "St. Croix sandstone" at Madison, Dane County, Wis. (L. C. Wooster, 1883; Cooper Cur- tice, 1884; and J. James, 1889). Lingulella oweni. 86. Upper Cambrian: "St. Croix sandstone" at Van Ness quarry, Gibraltar Bluff, Lodi, Columbia County, Wis. (L. C. Wooster, 1883; Cooper Curtice, 1884). Obolus (Westonia) aurora. Lingulella mosia. *Lingulella oweni. 86a. Upper Cambrian: "St. Croix sandstone" near Red Wing, Goodhue County, Minn. (Cooper Curtice, 1884). Lingulella similis. | *Otusia sandbergi. Billingsella coloradoensis. ! *Eoorthis remnicha.'' 87. Lower Cambrian: Limestone 1 mile (1.6 km.) south-southwest of Highgate Falls, Franklin County, Vt. (C. D. Walcott, 1885). Micromitra (Paterina) labradorica swantonensis. Obolus? sp. undt. *Lingulella franklinensis. 87'. Upper Cambrian: Limestone 1 mile (1.6 km.) south-southwest of Highgate Falls, Franklin County, Vt. *Obolus sp. undt. d. This species is labeled as coming from locality No. 87, but horizon is given as Upper Cambrian instead of Lower Cambrian. 88a. Middle Cambrian: Limestone about 100 feet (30.5 m.) above the quartzitic sandstone at the base of the Cambrian, in the northern suburbs of Deadwood, in the Black Hills, South Dakota (C. D. Walcott, 1887). Acrotreta idahoensis. Ptychoparia vacuna Walcott. Liostracus panope (Walcott). Lingulella ampla. Lingulella desiderata. *Lingulella similis. *Linnarssonella girtja. 89. (For stratigraphic position and association, see p. 147.) Middle Cambrian: Limestone in Murphrees Valley, Blount County, Ala. (A. M. Gibson, 1884). Lingulella (Lingulepis) acuminata. *Dicellomus appalachia. 90. (For stratigraphic position and association, see p. 147.) Middle Cambrian: Conasauga (" Coosa ") shale on Edward's farm, near Craigs Mountain, about 10 miles (16.1 km.) southeast of Center, Cherokee County, Ala. (Cooper Curtice, 1885). *Wimanella? anomala. Olenoides curticei Walcott. Olenoides sp. Micromitra (Paterina) major. Obolus (Westonia) ella. Lingulella similis?. Acrotreta kutorgai. 90a. (For stratigraphic position and association, see p. 147.) Middle Cambrian: Shales at Cedar Bluff, Cherokee County, Ala. (Bufford, 1892). Dicellomus appalachia. 90b. (For stratigraphic position and association, see p. 147.) Middle Cambrian: Conasauga limestone in cut on Louisville and Nashville Railroad, near Woodstock, Bibb County, Ala. (Chas. Butts, 1904). Lingulella buttsi. Lingulella desiderata. Dicellomus appalachia Acrotreta kutorgai. Agnostus. Ptychoparia. 90c. (For stratigraphic position and association, see p. 147.) Middle Cambrian: Conasauga limestone near Kimbrel, Bibb County, Ala. (Chas. Butts, 1904). *Lingulella buttsi. a Winchell [1886, p. 317] gives the type locality as St. Croix sandstone in sewer excavations at the corner of Brush and Main streets, Red Wing, Minn. 218 CAMBRIAN BRACHIOPODA. 90x (=94a). (For stratigraphic position and association, see p. 147.') Middle Cambrian: In and atlaciied to the outer surface of siliceous nodules in the Conasauga ("Coosa ") shale, Coosa Valley, east of Center, Cherokee County, Ala. CA. M. Gibson, 1884, and Cooper Curtice, 1885). Micromitra alabamaensis. *Lingulella hayesi. *Acrothele bellula. *Acrotreta kutorgai. Ptychoparia. Anomocare. Olenoides curticei Walcott. Laotira cambria Walcott. Brooksella alternata Walcott. 91. (For stratigraphic position and association, seep. 147.) Middle Cambrian: Conasauga (" Coosa ") shale at Cedar Bluff, Cherokee County, Ala. (A. M. Gibson, 1884, and Cooper Curtice, 1885'). Obolus willisi. I *Lingulella quadrilateralis. Lingulella nanno. | Dicellomus appalachia. 92b (the specimens are labeled 1092b). Upper Cambrian: Limestone on Buffalo Creek, 2 miles (3.2 km.) south- east of Buffalo Mills, Rockbridge County, Va. (C. D. Walcott, 1898). Obolus matinalis. Lingulella (Lingulepis) acuminata. 92x. (For stratigraphic position and association, see p. 147.) Middle Cambrian: Conasauga ("Coosa") shale at Yanceys Bend, Coosa River, southeast of Center, Cherokee Coimty, Ala. (Cooper Curtice, 1885). Obolus sinoe. Lingulella similis?. 93. (For stratigraphic position and association, see p. 147.) Upper Cambrian: Shales and limestones at the base of the Knox dolomite near Jordan's, just below the ford on Cowan Creek, about 8 miles (12.8 km.) southeast of Center, Cherokee County, Ala. (Cooper Curtice, 1885). Obolus willisi. Lingulella desiderata. 93a. (For stratigraphic position and association, see p. 147.) Upper Cambrian: Shales and limestones at the base of the Knox dolomite on Terrapin Creek road from Center to Amberson, Cherokee County, Ala. (Cooper Curtice, 1885). Lingulella desiderata?. 93n (16 of section). (For stratigraphic position and association, see p. 147.) Upper Cambrian: Shales in the south- em part of Jordan's farm, near Jordan's crossroads, about 8 miles southeast of Center, Cherokee County, Ala. (Cooper Curtice, 1885). Obolus willisi. 93o (=93). (For stratigraphic position and association, see p. 147.) (Cooper Curtice, 1885.) Lingulella desiderata. 93x. (For stratigraphic position and association, see p. 147.) Upper Cambrian : Shales on the Clarke farm, near the ford across Cowan Creek, about 2 miles (3.2 km.) north of Jordan's crossroads, southeast of Center, Cherokee County, Ala. (Cooper Curtice, 1885). Obolus willisi. 94 (see 94a, 94o, 94x, and 94xx; 8| of section). (For stratigraphic position and association, see p. 147.) Middle Cambrian: Shales 0.25 mile (0.4 km.) beyond Steel Ford, Cowan Creek, about 8 miles (12. 8 km.) southeast of Center, Cherokee County, Ala. (Cooper Curtice, 1885). *Micromitra alabamaensis. Obolus willisi. 94a (=shales in which nodules of 90x are embedded; see 94, 94o, 94x, and 94xx; 9 of section). (For stratigraphic position and association, see p. 147.) (Cooper Curtice, 1885.) Micromitra alabamaensis. Obolus willisi. Lingulella hayesi. 94o (see 94, 94a, 94x, and 94xx; 12 of section). (For stratigraphic position and association, see p. 147.") Upper Cambrian: Limestone at base of dolomite 0.25 mile (0.4 km.) beyond Givers Ford, Cowan Creek, about 8 miles (12.8 km.) southeast of Center, Cherokee County, Ala. (Cooper Curtice, 1885). Micromitra alabamaensis. Lingulella desiderata. Acrotreta sp. , . LOCALITIES. 219 94x (see 94, 94a, 94o, and 94xx). (For stratigraphin position and association, see p. 147.) Middle Cambrian: Shales 0.06 mile (0.1 km.) south of Giveng mill. Cowan Creek, about 8 miles (12.8 km.) southeast of Center, Cherokee County, Ala. (Cooper Curtice, 1885). Acrothele bellula. 94xx (see 94, 94a, 94o, and 94x; 10 of section). (For stratigraphic position and association, see p. 147.) Middle Cambrian: Limestone at base of dolomite at Givens mill. Cowan Creek, about 8 miles (12.8 km.) south- east of Center, Cherokee County, Ala. (Cooper Curtice, 1885). I/ingulella desiderata. Acrotreta sp. 95a. (For stratigraphic position and association, see p. 147.) Middle Cambrian: Shales on Spring Creek, near old tram crossing north of the Center road. Cowan Creek valley, southeast of Center, Cherokee County, Ala. (Cooper Curtice, 1885). Micromitra alabamaensis. 96. (For stratigraphic position and association, see p. 147.) Upper Cambrian: Limestone near the ford on the Cedarto^vn road, 1.5 miles (2.4 km.) south of Rome, Floyd County, Ga. (Cooper Curtice, 1885). Micromitra (Iphidella) pannula. I Lingulella desiderata. Obolus rotundatus. | *Lingulella leos. 96b. (For stratigraphic position and association, see p. 147.) Upper Cambrian: Shales in a railroad cut on the Southern Railway, near Cave Spring, 10 miles (16.1 km.) southwest of Rome, Floyd County, Ga. (Cooper Curtice, 1885). Obolus willisi. 96x. (For stratigraphic position and association, see p. 147.) Middle Cambrian: Limestone 1 mile (1.6 km.) north of Adairsville, 15 miles (24.2 km.) northwest of Cartersville, Cartersville quadrangle (U. S. G. S.), Bartow County, Ga. (Cooper Curtice, 1885). *Acrotreta concentrica. 97 (=97x and S97x, though possibly from a slightly different horizon). Upper Cambrian: "St. Croix sandstone" at Reads Landing, foot of Lake Pepin, Wabasha County, Minn. (Cooper Cm'tice, 1884). Obolus (Westonia) aurora. Lingulella oweni. Lingulella similis. Dicellomus politus. Billingsella coloradoensis. Eoorthis sp. *Syntrophia primordialis argia. 97a. Upper Cambrian: "St. Croix sandstone " near Winfield, Jefferson County, Wis. (Cooper Curtice, 1884). Lingulella similis. Lingulella (Lingulepis) acuminata. Billingsella coloradoensis. Eoorthis remnicha. Eoorthis remnicha sulcata. *Eoorthi3 remnicha winfieldensis. Eoorthis sp. 97b. Upper Cambrian: In the "St. Croix sandstone" below the green-sand bed and about 25 feet (7.6 m.) above St. Croix River, at Franconia, Chisago County, Minn. (Cooper Curtice, 1884). Obolus matinalis. Lingulella (Lingulepis) acuminata. Billingsella coloradoensis. 97c. Upper Cambrian: "St. Croix sandstone" at Winfield, Jefferson County, Wig. (Cooper Curtice, 1884). Lingulella similis. 97s. Upper Cambrian: "St. Croix sandstone" at Franconia, Chisago County, Minn. (Chas. Schuchert, 1893). Lingulella similis. 97x (=97, though possibly from a slightly different horizon). (Chas. Schuchert, 1893.) Eoorthis remnicha sulcata. S97x (=97, though possibly from a slightly different horizon). (Chas. Schuchert, 1893.) Dicellomus politus. Billingsella coloradoensis. 98 (=98x, though from a slightly different horizon). Upper Cambrian: "St. Croix sandstone" near Eau Claire Eau Claire County, Wis. (Cooper Curtice, 1884). Obolus matinalis. Lingulella phaon. *Obolus namouna. Lingulella (Lingulepis) acuminata. *Obolus rhea. Dicellomus politus. Lingulella ampla. Ptychoparia on ustus (Whitfield). Lingulella mosia osceola. Hyolithes. 220 CMIBRIAN BRACHIOPODA. 98a. Upper Cambrian: "St. Croix sandstone" at Marine Mills, on St. Croix River, Washington Comity, Minn. Lingulella mosia. Dicellomus politus. Billingsella coloradoensis. Ptychoparia sp. Ptychaspis granulosa (Owen). 98x (=9S, though from a slightly different horizon). (Cooper Curtice, 1884.) Obolus matinalis. I *Lingulella phaon. Lingulella mosia. | Dicellomus politus. 99. Upper Cambrian: "St. Croix sandstone " at Minneiska (Miniska), on Mississippi River, near the line between Wabasha and Winona counties, Minn. (Cooper Curtice, 1884). Syntrophia primordialis. 99a. Upper Cambrian: "St. Croix sandstone" near Pilot Knob, Adams County, Wis. (Cooper Curtice, 1884). Lingulella mosia. Lingulella (Lingulepis) acuminata. Eoorthis remnicha winfieldensis. 100. LTpper Cambrian: "St. Croix sandstone" near Menomonie, Dunn County, Wis. (Cooper Curtice, 1884). Obolus matinalis. Obolus sp. undt. Lingulella ampla. Lingulella mosia. Lingulella winona convexa. Dicellomus pectenoides. Dicellomus politus. Billingsella coloradoensis. 100a. Upper Cambrian: "St. Croix sandstone" at Ettrick, Trempealeau County, Wis. (Cooper Curtice, 1884). Dicellomus politus. 101 (2.5 feet above 101a; same horizon as 102). (For stratigraphic position and association, see p. 147.) Middle Cambrian: Rogersville shale just above the road in the hill west of the schoolhouse 3.5 miles (5.6 km.) southwest of Rogersville, on the I'oad to Melinda Ferry [see Keith, 1896a, areal geology sheet], Hawkins County, Tenn. (R. R. Gurley, 1887). Micromitra (Iphidella) pannula. Obolus lamborni minimus. 101a (25 feet below 101). (For stratigraphic position and association, see p. 147.) Middle Cambrian: Rogersville shale just above the road in the hill west of the schoolhouse 3.5 miles (5.6 km.) southwest of Rogersville, on the road to Melinda Ferry [see Keith, 1896a, areal geology sheet], Hawkins County, Tenn. (R. R. Gurley, 1887). *Obolus lamborni minimus. Lingulella desiderata. *Acrotreta rudis. 101b. (For stratigraphic position and association, see p; 147.) Middle Cambrian: Rogersville shale just east of the schoolhouse 3.5 miles (5.6 km.) southwest of Rogersville, on the road to Melinda Ferry [see Keith, 1896a, areal geology sheet], Hawkins County, Tenn. (R. R. Gurley, 1887). Obolus lamborni. Obolus willisi. Lingulella desiderata. 102 (same horizon as 101). (For stratigraphic position and association, see p. 147.) Middle Cambrian: Rogersville shale just south of road 0.5 mile (0.8 km.) southwest of Rogersville, on the road to Melinda Ferry [see Keith, 1896a, areal geology sheet], Hawkins County, Tenn. (R. R. Gurley, 1887). Obolus lamborni. • ' Dicellomus appalachia. 102c. (For stratigraphic position and association, see p. 147.) Middle Cambrian: First shale south of the Estill- ville pike, 3.5 miles (5.6 km.) east of Rogersville, Greeneville quadrangle (U. S. G. S.), Hawkins County, Tenn. (R. R. Gurley, 1887). Acrotreta rudis. 103 (below 103a). (For stratigraphic position and association, see p. 147.) Middle Cambrian: Second shale south of the ridge of sandstone in the Rome formation ("Town Knobs"), on the road from Rogersville to Dodson Ford, near the line between the Morristown and Greeneville quadrangles (U. S. G. S.), Hawkins County, Tenn. (R. R. Gurley, 1887). Obolus lamborni. LOCALITIES. 221 103a (immediately underlying 103b). (For stratigraphic position and association, see p. 147.) Middle Cambrian: Upper part of the second shale south of the ridge of sandstone in the Rome formation ("Town Knobs"), on the road from Rogersville to Dodson Ford, near the line between the Morristown and Greeneville quadrangles (U. S. G. S.), Hawkins County, Term. (R. R. Gurley, 1887). Obolus lambomi minimus. Dicellomus appalachia. 103b (immediately overljdng 103a). (For stratigraphic position and association, see p. 147.) Middle Cambrian: Third limestone (100 yards (90 m.) down the road toward the river from 103a) south of the ridge of sandstone in the Rome formation ("Town Knobs "), on the road from Rogersville to Dodson Ford, near the line between the Morristown and Greeneville quadrangles (U. S. G. S.), Hawkins County, Tenn. (R. R. Gurley, 1887). LinguleUa desiderata. 104. (For stratigraphic position and association, see p. 147.) Middle Cambrian: Shale in railroad cut 0.5 mile (0.8 km.) from Rogersville, on the road to Holston River, near the line between the Morristown and Greene- ville quadrangles (U. S. G. S.), Hawkins County, Tenn. (R. R. Gurley, 1887). Dicellomus appalachia. 105. (For stratigraphic position and association, seep. 147.) Upper Cambrian: Limestone in Knox dolomite at Bishops mill, Hancock County, Tenn. (Ira Sayles, 1884). LinguleUa (Lingulepis) acuminata. lost. (For stratigraphic position and association, see p. 153.) Lower Ordovician: Thin-bedded bluish-gray lime- stone [Walcott, 1908f, p. 173, and Pis. XIII and XIV], at the summit of Notch Peak, House Range, Millard County, Utah (C. D. Walcott, F. B. Weeks, and L. D. Burling, 1905). *Obolus (Westonia) notchensis. Eoorthis desmoplemra. Raphistoma sp. 105x. (For stratigraphic position and association, see p. 148.) Middle Ordovician: Gray siliceous shales just below a band of quartzitic sandstones probably corresponding in position to the upper part of the Simpson forma- tion of the Oklahoma section, in Wasatch Canyon, east of Lakeview ranch, about 5 miles (8 km.) north of Brigham, Boxelder County, Utah (F. B. Weeks and L. D. Burling, 1905). *Obolua (Westonia) elongatus. 106. (For stratigraphic position and association, see p. 147.) Middle Cambrian: Shales of the Rome formation on the roadside at the eastern base of Shocks Gap, in Bays Mountains, 10 miles (16.1 km.) southeast of Knoxville [see Keith, 1895, areal geology sheet], Knox County, Tenn. (Cooper Curtice, 1885). LinguleUa stmilis. 106a. (For stratigraphic position and association, see p. 147.) Middle Cambrian: Reddish-brown shales in middle of valley east of Shooks Ridge, in Bays Mountains, 10 miles (16.1 km.) southeast of Knoxville, Knox County, Tenn. (Cooper Curtice, 1885). Obolus willisi. 107 (just above 107a). (For stratigraphic position and association, see p. 147.) Middle Cambrian: Limestone in Bull Run, northwest of Copper Ridge [Keith, lS96b, areal geology sheet], 11 miles (17.6 km.) northwest of Knoxville, Knox County, Tenn. (Cooper Curtice, 1885). Dicellomus appalachia. Wimanella harlanensis. 107a (just below 107, above 107b). (For stratigraphic position and association, see p. 147.) Middle Cambrian: Shales in railroad cut in Bull Run, northwest of Copper Ridge [Keith, 1896b, areal geology sheet], 11 miles (17.6 km.) northwest of Knoxville, Knox County, Tenn. (Cooper Curtice, 1885). Obolus willisi. LinguleUa desiderata ?. 107b (below 107a). (For stratigraphic position and association, see p. 147.) Middle Cambrian: Shales and sand- stones of the Rome formation in railroad cut in Bull Run, northwest of Copper Ridge [Keith, 1896b, areal geology sheet], 11 miles (17.6 km.) northwest of Kjaoxville, Knox County, Tenn. (Cooper Curtice, 1885). Obolus willisi. I Dicellomus appalachia. LinguleUa?. | Linnaissonella tennesseensis. 222 CMIBRIAN BRACHIOPODA. 1070 (just above 107u). (For stratigraphic position and association, see p. 147.) Upper Cambrian: Limestones and shales at the base of the Knox dolomite west of the top of Copper Ridge, near the Southern Railway cut, about 10 miles (16.1 km.) northwest of Knoxville [see Keith, 1896b, areal geology sheet], Knox County, Tenn.. (Cooper Curtice, 1885). Lingulella desiderata. Lingulella (Lingulepis) acuminata. Acrotreta kutorgai. 107u (just below 107o). (For stratigraphic position and association, see p. 147.) Upper Cambrian: Limestones and shales at the base of the Knox dolomite west of the top of Copper Ridge, near the Southern Railway cut; about 10 miles (16.1 km.) northwest of Knoxville [see Keith, 1896b, areal geology sheet], Knox County, Tenn. (Cooper Curtice, 1885). Lingulella desiderata?. Acrotreta kutorgai. 108. Upper Cambrian: Sandstone 1 mile (1.6 km,) south of Poughkeepsie, Dutchess County, N. Y. (C. D. Walcott, •1886). Lingulella (Lingulepis) acuminata. 109 (see 367k). Upper Cambrian: Sandstone 25 feet (7.6 m.) above the Archean 1.5 miles (2.4 km.) south o£ Deweys Bridge, on the Champlain Canal, Washington County, N. Y. (C. D. Walcott, 1886). Lingulella (Lingulepis) acuminata. 110 (just below 110a). Upper Cambrian: Shaly calcareous sandstone resting on massive layers of Potsdam sand- stone, east side of the town of Whitehall, Washington County, N. Y. (C. D. Walcott, 1886). Lingulella (Lingulepis) acuminata. 110a (just above 110). Upper Cambrian: Sandstone on the east side of the town of Whitehall, Washington County^ N. Y. (C. D. Walcott, 1886). Lingulella (Lingulepis) acuminata. 111. Upper Cambrian: At the top of the Potsdam sandstone on Marble River, 1 mile (1.6 km.) south of Chateaugay,. FrankUn County, N. Y. (C. D. Walcott, 1886). Lingulella (Lingulepis) acuminata. 113. Upper Cambrian: "St. Croix sandstone" at La Grange Mountain (or Barn Bluff), near Red Wing, Goodhue County, Minn. (Cooper Curtice, 1884). Lingulella mosia. Lingulella winona. 114 (above 114a). (For stratigraphic position and association, see p. 140.) Upper Cambrian: Upper sandstone beds on Little Belle Island, Conception Bay, Newfoundland (C. D. Walcott, 1888). Lingulella bella. Lingulella bellula. 114a (below 114). (For stratigraphic position and association, see p. 140.) Upper Cambrian: Sandy shales under- lying beds of Locality 114, Little Belle Island, Conception Bay, Newfoundland (C. D. Walcott, 1888). Lingulella bella. *Lingulella bellula. 114b. (For stratigraphic position and association, see p. 140.) Lower Ordovician: Sandstone 1 mile (1.6 km.> north of Lance Cove, Great Belle Island, Conception Bay, Newfoundland (C. D. Walcott, 1888). *Obolus (Lingulobolus) affinis. I Obolus (Westonia) rogersi. *Obolu8 (Lingulobolus) spissus. | *Lingulella bella. 116. Upper Cambrian: "St. Croix sandstone" in excavation on Wells farm, 2 miles (3.2 km.) west of Baraboo„ Baraboo quadrangle (U. S. G. S.), Sauk County, Wis. *Billingsella major. 117. (For stratigraphic position and association, see p. 147.) Middle Cambrian: Shales on the road north from Greeneville, Greene County, Tenn. (Cooper Curtice, 1886). Lingulella desiderata. 117c. (For stratigraphic position and association, see p. 147.) Middle Cambrian: Shale at Buckingham Ford on HoUis Creek, 5 miles (8 km.) southeast of Greeneville, Greene County, Tenn. (Cooper Curtice, 1886). Dicellomus appalachia. LOCALITIES. 223 118 (same horizon as 117c). (For stratigraphic position and association, see p. 147.) Middle Cambrian: Shales on the Tazewell road, 2 miles (3.2 km.) north of KnoxviUe, Knox County, Tenn. (M. R. Campbell, 1891). Obolus lamborni minimus. 119. (For. stratigraphic position and association, see p. 147.) Middle Cambrian: Limestone in various localities in Jefferson and Hawkins counties, Tenn. (Ira Sayles, 1885). Dicellomus appalachia. 121. (For stratigraphic position and association, see p. 147.) Middle Cambrian: Rogersville shale, road just east of Harlan Knob, 4 miles (6.4 km.) northeast of Rogersville [see Keith, 1905, areal geology sheet], Hawkins County, Tenn. (C. D. Walcott, 1891). Acrotreta rudis. *Billingsella? appalachia. *Wimanella harlanensis. Micromitra alabamaensis. Obolus lamborni. Obolus willisi. Lingulella desiderata. 121a (For stratigraphic position and association, see p. 147.) Middle Cambrian: Shales on road leading from southeast of Harlan Knob to Amis post office, about 4 miles (6.4 km.) northeast of Rogers\ille [see Keith, 1905, areal geology sheet], Hawkins County, Tenn. (C. D. Walcott, 1891). Micromitra alabamaensis. 122. (For stratigraphic position and association, see p. 147.) Upper Cambrian: Shale southwest of "Town Knobs ",a 1 mile (1.6 km.) southwest of Rogersville, Hawkins County, Tenn. (C. D. Walcott, 1891). Obolus willisi. Lingulella desiderata. 122a. (For stratigraphic position and association, see p. 147.) Upper Cambrian: Shale at the headwaters of For- gey Creek, northwestern part of the GreeneNdlle quadrangle (U. S. G. S.), Hawkins County, Tenn. (C. D. Walcott, 1891). Obolus lamborni. Lingulella desiderata. 123. (For stratigraphic position and association, see p. 147.) Middle Cambrian: Upper part of Maryville lime- stone on Big Creek, southeast of Harlan Knob, 4 miles (6.4 km.) northeast of Rogers\dlle [see Keith, 1905, p. 4, and areal geology sheet], Hawkins County, Tenn. (C. D. Walcott, 1891). Micromitra alabamaensis. Ptychoparia. 124 (=124a). (For stratigraphic position and association, see p. 147.) Middle Cambrian: Shales (Nolichucky?) overlying the limestone which rests on the Rogersville shale on Big Creek, southeast of Harlan Knob, 4 miles (6.4 km.) northeast of Rogersville [see Keith, 1905, p. 4, and areal geology sheet], Hawkins County, Tenn. (C. D. Walcott, 1891). Micromitra alabamaensis. Obolus lamborni minimus. 124a (=124). (For stratigraphic position and association, see p. 147.) (C. D. Walcott, 1891.) Obolus lamborni. Lingulella (Lingulepis) acuminata. Dicellomus appalachia. 128. (For stratigraphic position and association, see p. 147.) Upper Cambrian: Shale 1.5 miles (2.4 km.) south- west of Cleveland, Bradley County, Tenn. (C. D. Walcott, 1891). Lingulella?. 128a. (For stratigraphic position and association, see p. 147.) Upper Cambrian: Shales on the Louis\'ille and Nashville Railroad, 1.5 miles (2.4 km.) southeast of Cog Hill, near the line between Polk and McMinn counties, Tenn. (M. R. Campbell, 1891). Lingulella sp. Dicellomus politus. 131. Upper Cambrian: Sandstone in a cut on the Chicago, Milwaukee and St. Paul Railway, 4 miles (6.4 km.) southeast of Lake City, Wabasha County, Minn. (C. Schuchert, 1893). BiUingsella coloradoensis. 134. Upper Cambrian: "St. Croix sandstone" in the lowest beds exposed along the banks of Red Cedar River, opposite Menomonie, Dunn County, Wis. (C. Schuchert, 1893). Obolus matinaUs. a See localities 103, 103a, and 103b, pp. 220-221. 224 CAMBRIAN BRACHIOPODA. 134a. Upper Cambrian: "St. Croix sandstone" in a quarry 1 mile (1.6 km.) southeast of the county courthouse, in Menomonie, Dunn County, Wis. (C. Schuchert, 1893). Syntrophia barabuensis. 136. Upper Cambrian: "St. Croix sandstone'" near Trempealeau, Trempealeau County, Wis. (C. Schuchert, 1893). Lingulella winona convexa. 135b. Upper Cambrian: "St. Croix sandstone" near Trempealeau, Trempealeau County, Wis. (C. Schuchert, 1893). Finkelnbm'gia finkelnbm'gi. 135c (=83'). Upper Cambrian: Uppermost horizon of the "St. Croix sandstone" near Trempealeau, Trem- pealeau County, Wis. (C. Schuchert, 1893). Finkelnburgia finkelnburgi. Finkelnburgia osceola. Dikollocephalus minnesotensis Owen. 136. Upper Cambrian : Potsdam sandstone in bank of stream opposite the first switch on the Port Henry and Maine Raihoad out of Port Henry, Essex County, N. Y. (C. D. Walcott, 1889). Lingulella prima. 137. (For stratigraphic position and association, see p. 147.) Middle Cambrian: Shales on southeast side of north- east end of Cane Creek Mountains, 3 miles (4.8 km.) south of Gadsden, Etowah County, Ala. (Cooper Curtice, 1892). . , Acrotreta kutorgai. 138. (For stratigraphic position and association, see p. 147.) Middle Cambrian: Shale in the street northeast of Printuf House, Gadsden, Etowah County, Ala. (Cooper Curtice, 1892). . Lingulella similis. 138a. (For stratigi-aphic position and association, see p. 147.) Middle Cambrian: Shales in the Rome formation west of the cemetery west of Rome, Floyd County, Ga. (Cooper Curtice, 1892). Lingulella similis. 139. (For stratigraphic position and association, see p. 147.) Middle Cambrian: Limestone on Hokes Bluff road north o"f the chert outcrop, 5 miles (8 km.) east of Gadsden, Etowah County, Ala, (Cooper Curtice, 1892). Lingulella desiderata. 139a. (For stratigraphic position and association, see p. 147.) Middle Cambrian: Limestone on road near Wades Gap, near Chepultepec, Jefferson County, Ala. (Cooper Curtice, 1892). Acrotreta kutorgai. 140. (For stratigraphic position and association, see p. 147.) Middle Cambrian: Limestone interbedded in shales near Chepultepec, Jefferson County, Ala. (Cooper Curtice, 1892). Acrotreta kutorgai. 140a. (For stratigraphic position and association, see p. 147.) Middle Cambrian: Shales 200 yards (182.9 m.) east of Thomas Mills, .5 miles (8 km.) north of Cave Spring [see Hayes, 1902, historical geology sheet], Floyd County, Ga. (Cooper Curticer, 1892). Obelus lamborni. Obolupwillisi. Lingulella quadrilateralis. 140c. (For stratigraphic position and association, see p. 147.) Middle Cambrian: Shale at edge of hill on the road leading west of Cave Spring, 10 miles (16.1 km.) southwest of Rome, Floyd County, Ga. (Cooper Curtice, 1892). Lingulella similis. Lingulella sp. 141a. (For stratigraphic position and association, see p. 147.) Middle Cambrian: Limestone 0.25 mile (0.4 km.) west of the hotel at Montevallo, Shelby County, Ala. (Cooper Curtice, 1892). Obolus (Westonia) ella. 142. (For stratigraphic position and association, see p. 147.) Middle Cambrian: Shales just above the Olenellus zone near the railroad 4.5 mUes (7.2 km.) north of Montevallo, Shelby County, Ala. (Cooper Curtice, 1892). Acrotreta kutorgai?. LOCALITIES. 225 1440. (For stratigraphic position and association, see p. 147.) Middle Cambrian: Limestone near the top of the beds exposed near N. K. Burns's bams, near Viola, Blount County, Ala. (Cooper Curtice, 1892). Dicellomus appalachia. 145. (For stratigraphic position and association, see p. 147.) Middle Cambrian: Shale in bluff on Coosa River east of Turkeytown, 8 miles (12.8 km.) northeast of Gadsden, Etowah County, Ala. (Biddle and Russell, 1886). Lingulella similis. 146. (For stratigraphic position and association, see p. 147.) Middle Cambrian: Conasauga ("Coosa") shale on the Jacksonville road, 8 mUes (12.8 km.) east of Center, Cherokee County, Ala. (Biddle, 1883). Obolus wUlisi. 147a. Upper Cambrian: Limestone in Spring Hill Canyon, west side of the Bridger Range, Gallatin County, Mont. (A. C. Peale, 1885). BUlingsella coloradoensis. 148a. Upper Cambrian : Limestone of the Gallatin formation at the head of Bostwick Canyon (the name is given on the Threeforks sheet (U. S. G. S.)) [Iddings and Weed, 1894, areal geology sheet "], in the Bridger Range, Livingston quadrangle (U. S. G. S.), Gallatin County, Mont. (A. C. Peale, 1885). Obolus tetonensis. 149a. Middle Cambrian: Limestone at the forks of Pole Creek, above Cherry Creek basin, Threeforks quadrangle (U. S. G. S.), Madison County, Mont. (A. C. Peale, 1887). Micromitra (Iphidella) pannula. *Billingsella striata. 150a. Upper Cambrian: Limestone on the east side of Dry Creek, above the mouth of Pass Creek, about 5 miles (8 km.) north of Hillsdale, Threeforks quadrangle (U. S. G. S.), Gallatin County, Mont. (A. C. Peale, 1885). Billingsella plicatella. Eoorthis wichitaensis. 151 (see 151a). Upper Cambrian: Limestone in point overlooking Chum Canyon, on the west side of the Bridger Range, Gallatin County, Mont. (A. C. Peale, 1885). Obolus discoideus. Billingsella plicatella. Eoorthis wichitaensis. 151a (a little higher horizon than 151, same locality). Upper Cambrian: Limestone in point overlooking Chum Canyon, on the west side of the Bridger Range, Gallatin County, Mont. (A. C. Peale, 1885). Dicellomus pectenoides. Billingsella plicatella. 152. Upper Cambrian: Limestone on ridge between Chum and Cottonwood canyons, west side of Bridger Range, Gallatin County, Mont. (A. C. Peale, 1885). Billingsella plicatella. Eoorthis desmopleura?. 152a. Upper Cambrian: Limestone on west side of Dry Creek, below Pass Creek, Threeforks quadrangle (U. S. G. S.), Gallatin County, Mont. (A. C. Peale, 1885). Dicellomus nanus. 152b. Upper Cambrian: East side of Dry Creek, below Pass Creek, Threeforks quadrangle (U. S. G. S.), Gallatin County, Mont. (A. C. Peale, 1885). Obolus tetonensis?. 153 (slightly different horizon than 153a). Upper Cambrian: Limestone in ravine on west side of Dry Creek, near the mouth of Pass Creek, about 5 miles (8 km.) north of Hillsdale, Threeforks quadrangle (U. S. G S ), Gallatin County, Mont. (A. C. Peale, 1885). Billingsella plicatella. Huenella abnormis. 153a (slightly different horizon than 153). Upper Cambrian: Limestone in ravine on west side of Dry Creek, near the mouth of Pass Creek, about 5 miles (8 km.) north of Hillsdale, Threeforks quadrangle (U. S. G. S.), Gallatin County, Mont. (A. C. Peale, 1885). Eoorthis remnicha. * Eoorthis remnicha texana. Eoorthis wichitaensis. o Iddings, J. P., and Weed, W. H., Livingston folio (No. 1), Geo!. Atlas TJ. S., XJ. S. Geol. Survey, 1S94. 62667°— VOL 51, PT 1—12 15 226 CMIBRIAN BRACHIOPODA. 154. Upper Cambrian: Limestone in hill on west side of Dry Creek, opposite mouth of Pass Creek, about 5 miles (8 km.) north of Hillsdale, Threeforks quadrangle {V. S. G. S.), Gallatin County, Mont. (A. C. Peale, 1885). Billingsella plicatella. Eoorthis desmopleura?. Eoorthis remnicha. 155. Upper Cambrian: Limestone north of East Gallatin River, near Hillsdale, Threeforks quadrangle (U. S. G. S.), Gallatin County, Mont. (A. C. Peale, 1888). Billingsella coloradoensis. 155a. Middle Cambrian: Limestone north of East Gallatin River, near Hillsdale, Threeforks qu"drangle (U. S. G. S.), Gallatin County, Mont. (A. C. Peale, 1888). *Micromitra pealei. 156a. Middle Cambrian: Limestones of the Flathead formation [Peale, 1893, p. 20], north of East Gallatin River, near Hillsdale, Gallatin County, Mont. (A. C. Peale. 1888). Acrotreta attenuata. 156b. LTpper Cambrian: Limestone north of East Gallatin River, at the north end of the Gallatin Valley, Threeforks quadrangle (U. S. G. S.), Gallatin County, Mont. (A. C. Peale, 1884). Billingsella plicatella. 157 (same locality as 158 and 156, but different horizon). Upper Cambrian: Limestone north of East Gallatin River, near Hillsdale, Threeforks quadrangle (U. S. G. S.), Gallatin County, Mont. (A. C. Peale, 1888). Billingsella plicatella. Huenella abnormis. 158 (same locality as 156, 157, and 158a, but different horizon). Upper Cambrian: Limestone north of East Gallatin River, near Hillsdale, Threeforks quadrangle (U. S. G. S.), Gallatin County, Mont. (A. C. Peale, 1889). Dicellomus pectenoides. I Eoorthis desmopleura. *Billingsella plicatella. - | Huenella abnormis. 158a (same locality as 156. 157, and 158, but different horizon). Upper Cambrian: Limestone north of East Gallatin River, near Hillsdale, Threeforks quadrangle (U. S. G. S.), Gallatin County, Mont. (A. C. Peale, 1889). Dicellomus nanus. 159. Middle Cambrian: Limestones north of West Gallatin (Gallatin) River, Gallatin County, Mont. (A. C. Peale, 1884). Billingsella coloradoensis. Olenoides?. Micromitra pealei. Obolus rotundatus. Acrotreta attenuata. 160. Upper Cambrian: Sandstones forming a remnant of the Gallatin formation which lies between the exposures of "porphyrite" on the east side of Willow Creek [Peale, 1896, areal geology sheet], 12 miles (19.2 km.) south-southwest of Threeforks, Threeforks quadrangle (U. S. G. S.), Gallatin County, Mont. (A. C. Peale, 1889). Micromitra (Paterina) superba?. 160a. Upper Cambrian: Sandstone west of Bear Creek, south of the Gallatin VaJey southwest of Bozeman, Threeforks quadrangle (U. S. G. S.), Gallatin County, Mont. (A. C. Peale, 1889). Obolus rotundatus. 161. Upper Cambrian: Limestone on the south side of West Gallatin (Gallatin) River, northwest of Hamilton on the north side of the Gallatin Valley, Gallatin County, Mont. (A. C. Peale, 1884). Obolus tetonensis. Lingulella desiderata. 163 (=55c). (For stratigraphic position and association, see p. 152.) (R. S. Spence., *Nisusia (Jamesella) nautes. *Nisusia (Jamesella) spencei. Micromitra (Iphidella) pannula. Acrothele subsidua. *Acrotreta definita. 164. Middle Cambrian: Sandstone in the Deadwood formation in the cliffs on the east side of the valley near Deadwood, Black Hills, Seuth Dakota. Dicellomus pectenoides. 164f. (For stratigraphic position and association, see p. 147.) Middle Cambrian: Shales just above a bed of limestone on the road leading northwest out of Montevallo, Shelby County, Ala. Obolus? sp. LOCALITIES. 227 165. Middle Cambrian: Limestone on the east side of the valley, in railroad cut about 1 mile (1.6 km.) below the main part of Deadwood, Black Hills, South Dakota. Lingulella similis. Acrotreta idahoensis. Linnarssonella girtyi. 167. Middle Cambrian: Sandstone beneath limestone and resting on pre-Cambrian "slates, schists, and peg- matites" in bluff 9 miles (14.4 km.) west of Custer, Black Hills, South Dakota. Lingulella cuneola?. Lingulella (Lingulepis) acimiinata. Dicellomus poUtus. 168. Upper Cambrian: Limestones on north side of Tepee Creek, near the road from Sheridan to Dome Lake, Bighorn Mountains, Sheridan County, Wyo. (C. D. Walcott). Eoorthis desmopleura . I Eoorthis remnicha. *Eoorthis desmopleura nympha. ■ | Syntrophia primordialis. 170. Middle Cambrian: Sandstone about 10 miles (16.1 km.) south-southeast of Bald Moimtain, Bighorn Moun- tains, Wyo. Obelus matinalis. Dicellomus nanus. 171 (200 feet below 171a). Middle Cambrian: Sandstone in Big Goose Creek Canyon, in the Bighorn Mountains,, west of Sheridan, Sheridan County, Wyo. Lingulella (Lingulepis) acuminata (ranging through 200 feet of beds). 171a (200 feet above 171). Middle Cambrian: Sandstone in Big Goose Creek Canyon, in the Bighorn Mountains, west of Sheridan, Sheridan County, Wyo. Obolus (Westonia) ella. Lingulella (Lingulepis) acuminata. 174c. (For stratigraphic position and association, see p. 138.) Lower Cambrian: Sandstones on small hill in the salt flat 1 mile (1.6 km.) northeast of Silver Peak mill. Silver Peak quadrangle (U. S. G. S.), Esme- ralda County, Nev. (C. D. Walcott and F. B. Weeks, 1896). *Mickwitzia occidens. Obolus?. Obolella sp. 175. (For stratigraphic position and association, see p. 138.) Lower Cambrian: Shales carrying Olenellus on the divide between Clayton and Fish Lake valleys, about 15 miles (24.2 km.) south-southwest of the town of Silver Peak, Silver Peak quadrangle (U. S. G. S.), Esmeralda County, Nev. (C. D. Walcott and F. B. Weeks, 1896). Obolus?. I *Acrotreta claytoni. Kutorgina perugata?. | Swantonia? sp. 176. (For stratigraphic position and association, seep. 138.) Lower Cambrian: Shales and interbedded lime- stones between massive limestone containing Archxocyathus, at the south end of Deep Spring Valley, Inyo County, Cal. (C. D. Walcott and F. B. Weeks, 1896). Obolella vermihonensis. Obolella? sp. Trematobolus excelsis. Wanneria gracile Walcott. Olenellus fremonti Walcott. 176a. (For stratigraphic position and association, seep. 138.) Lower Cambrian: Sandstone on ridge east of the head of Mazouka Canyon, Inyo Range, Inyo County, Cal. (C. D. Walcott, 1897). Trematobolus excelsis. 178a (slightly higher than 176, but same locality). (For stratigraphic position and association, see p. 138.) (C. D. Walcott and P. B. Weeks, 1896.) Trematobolus excelsis. I Wanneria gracile Walcott. BilUngsella highlandensis?. | Olenellus fremonti Walcott. 184. (For stratigraphic position and association, see p. 138.) Lower Cambrian: Shales at the summit of the Silver Peak Range, 10 miles (16.1 km.) southwest of the town of Silver Peak, Silver Peak quadrangle (U. S. G. S.), Esmeralda County, Nev. (C. D. Walcott, 1896). Kutorgina perugata. Acrotreta claytoni. 228 CAMBEIAN BKACHIOPODA. 185. Upper Cambrian: Sandy layers above the massive Potsdam sandstone 0.5 mile (0.8 km.) southeast of Redwood, Jefferson County, N. Y. (C. D. Walcott, 1886). Lingulella (Lingulepis) acuminata. 185a. Upper Cambrian: Sandy layers 20 feet (6 m.) above the massive Potsdam sandstone, east side of Indian View, 3 miles (4.8 kin.) south of Theresa, Jefferson County, N. Y. (C. D. Walcott, 1886). Lingulella (Lingulepis) acuminata. 185z. (For stratigraphic position and association, seep. 148.) Lower Ordovician: Limestones at the base of the Lower Ordovician [Walcott, 1908f, p. 191], in Blacksmith Fork Canyon, about 9 miles (14.4 km.) east of Hyrum, Cache County, Utah (C. D. Walcott and L. D. Burling, 1906). Obelus discoideus. Eoorthis desmopleura. Syntrophia nundina. Orthoceras. Endoceraa. Fragments of trilobites. 186. Lower Ordovician: Near line of contact between red and gray Ordovician limestone, in red siliceous lime- stone about 30 feet (9.1 m.) above the pre-Cambrian rocks, Williams Canyon, Manitou, El Paso County, Colo. (C. D. Walcott, 1890). Lingulella desiderata. Schizambon manitouensis. Eoorthis desmopleura. Eoorthis desmopleura nympha. Syntrophia nundina. 186a (slightly higher horizon than 186). Lower Ordovician: Near line of contact between red and gray Ordovician limestone, in siliceous red limestone about 35 feet (10.7 m.) above the pre-Cambrian rocks, Williams Canyon, Manitou, El Paso County, Colo. (T. W Stanton, 1890). *Schizambon manitouensis. ' Eoorthis desmopleura. Syntrophia nundina. 187. Lower Ordovician: Red siliceous limestone 105 to 122 feet (32 to 36. 7 m.) above the pre-Cambrian rocks, 2 miles (3.2 km.) below Manitou Park Hotel, El Paso County, Colo. (^Tiitmau Cross, 1882). Lingulella desiderata. Eoorthis desmopleura. 201. (For stratigraphic position and association, see p. 139.) Passage beds between the LTpper Cambrian and the Ordovician: Arenaceous Pogonip limestone on east slope of ridge east of Hamburg Ridge Eureka district [Hague, 1892, Atlas], Eureka County, Nev. (Arnold Hague and C. D. Walcott, 1880). *Lingulella pogonipensis. Acrotreta idahoensis alta. Eoorthis hamburgensis. 201a. (For stratigraphic position and association, see p. 139.) Lower Ordovician: Pogonip limestone, east slope of the ridge east of Hamburg Ridge, Eureka district [H^ue, 1892, -Atlas], Eureka County, Nev. (C. D. Walcott, 1882). *Obolus (Westonia) iphis. Lingulella pogonipensis. *Schizambon typicalis. Acrothele sp. Acrotreta idahoensis. Eoorthis hamburgensis. Syntrophia nundina. Agnostus prolongus Hall and ^"hitfield. 202. (For stratigraphic position and association, see p. 139.) Lower Ordovician: Pogonip limestone on the summit of the ridge directly southeast of the Jackson mine, northwest of Shadow Canyon, Eureka district [Hague, 1892, Atlas], Eureka County, Nev. (C. D. Walcott, 1880). Lingulella manticula. I Elkania ambigua. Lingulella sp. | Acrotreta idahoensis. 203. (For stratigraphic position and association, see p. 139.) Lower Ordovician: Pogonip limestone on spur of Hamburg Ridge extending out southwest from Wood Cone, Eureka district [Hague, 1892, Atlas], Eureka County, Nev. (C. D. Walcott, 1880). Syntrophia nundina. Bathyurus congeneris Walcott. Bathyurus tuberculatus Walcott. 203a. (For stratigraphic position and association, seep. 139.) Passage beds between the Upper Cambrian and the Ordovician: Limestones at base of Pogonip limestone in the spur of Hamburg Ridge extending out southwest from Wood Cone, Eureka district [Hague, 1892, Atlas], Eureka County, Nev. (CD. Walcott, 1880). Lingulella pogonipensis. *Acrotreta curvata. Agnostus tumidosus Hall and Whitfield. LOCALITIES. 229 204. (For stratigraphic position and association, see p. 139.) Lower Ordovician: Pogonip limestone on the lower part of the eastern slope of the ridge east of Hamburg Ridge, facing Secret Canyon road. Eureka dis- trict [Hague, 1892, Atlas], Eureka County, Nev. (C. D. Walcott, 1880). *Syntrophia nundina. 205. (For stratigraphic position and association, see p. 139.) Passage beds between the Upper Cambrian and the Ordovician: Siliceous limestone on Roundtop Mountain, Eureka district [Hague, 1892, Atlas], Eureka County, Nev. (Arnold Hague and J. P. Iddings, 1880). Obelus maera. *Obolus (Westonia) sp. undt. b. Lingulella pogonipensis. *Acrotreta? cancellata. Eoorthis hamburgensis. 206a. (For stratigraphic position and association, see p. 139.) Pa^^sage beds between the Upper Cambrian and the Ordovician: Sandy limestone on Hoosac Mountain, Eureka district [Hague, 1892, Atlas], Eureka County, Nev. (C. D. Walcott, 1880). Acrotreta idahoensis alta. 209. (For stratigraphic position and association, see p. 139.) Lower Ordovician: Pogonip limestone on the west side of Goodwin Canyon, Eureka district [Hague, 1892, Atlas], Eureka County, Nev. (C. D. Walcott, 1880). Syntrophia nundina. 211. (For stratigraphic position and association, see p. 139.) Passage beds between the Upper Cambrian and the Ordovician: Siliceous Pogonip limestone on spur of Hamburg Ridge extending southwest from Wood Cone, Eureka district [Hague, 1892, Atlas], Eureka County, Nev. (Arnold Hague, J. P. Iddings, and C. D. Walcott, 1880). Lingulella pogonipensis. 214a (see 313k). (For stratigraphic position and association, see p. 139.) Ordovician: Near the base of the Pogonip limestone, WTiite Pine district, White Pine County, Nev. (C. D. Walcott and C. H. H., 1882). *Obolus sp. undt. c. 214b (see 313k). (For stratigraphic position and association, seep. 139.) Lower Ordovician: Limestones near the middle of the Pogonip limestone, White Pine district. White Pine County, Nev. (CD. Walcott and C. H. H., 1882). Lingulella manticula. 216a. Ordovician: Limestone at Fossil Butte, 10 milea north of Hyko, Lincoln County, Nev. (C. D. Walcott, 1885). Huenella sp. 220a. Ordovician: Shales of the "Upper Sillery " (Lauzon of Logan) on Chaudiere River, at the Grand Trunk Railroad bridge, Province of Quebec, Canada (C. D. Walcott, 1889). *Lingulella ellsi. *Acrothele pretiosa. 281. (For stratigraphic position and association, see p. 139.) Ordovician: Pogonip limestone, below the white quartzite, at the western base of Lone Mountain, Keyes Valley, 18 miles (28.8 km.) northwest of Eureka, Eureka Comity, Nev. (C. D. Walcott, 1880). Acrotreta sp. undt. 227. Lower Ordovician: Limestone near Fort Cassin, Addison County, Vt. (W. P. Rust, 1887). *Syntrophia lateralis. Localities 300-396z, arbitrarily numbered^ 300 [Matthew, 1886, p. 37]. (For stratigraphic position and association, see p. 132.) Middle Cambrian: Shaly sand- stones, possibly of Division Id of Matthew, on Long Reach, St. John River, Kings County, New Brunswick. *Acrotreta baileyi Matthew. Ptychoparia robbi ? (Hartt). 301 (references follow species; see 2h). (For stratigraphic position and association, see p. 133.) Middle Cambrian: In sandstones of Division lb2 of the "Protolenus zone" [Matthew, 1895a, p. 108], on Hanford Brook, St. John County, New Brunswick. Acrothele matthewi lata [Matthew, 1886, p. 42]. Acrotreta baileyi? [Matthew, 1886, p. 37]. Acrotreta gemmula [Matthew, 1895a, p. 126]. *Trematobolus insignis [Matthew, 1895a, p. 123]. *Trematobolus pristinus [Matthew, 1895a, p. 122]. *Beyrichona papilio [Matthew, 1886, p. 66]. *Beyrichona tinea [Matthew, 1886, p. 66]. a See the explanatory paragraphs on pp. 160-161. 230 CMIBRIAN BRACHIOPODA. 301a (references follow species). (For stratigraphic position and association, see p. 132.) Middle Cambrian: Fine- grained sandstones below the Protolouis-heaTing shales and sandstones in Division lb3 of Matthew, Hanford Brook, St. John County, New Brunswick. *Acrothele matthewi lata [IMatthew, 1895a, PI. V, fig. 8]. Acrothele matthewi prima [Matthew, 1895a, PI. V, fig. 7]. *Acrotreta gemmula [Matthew, 1894, p. SB]. *Diplotheca acadica crassa [Matthew, 1886, p. 55]. *Diplotheca hyattiana [Matthew, 1886, p. 52]. *Agraulos? articephalus [Matthew. 1886, p. 75]. 301b [Matthew, 1895a, p. 126]. (For stratigraphic position and association, see p. 132.) Middle Cambrian: Sand stones of Division lb5 and higher of the " Protolenus zone" [Matthew, 1895a, p. 108], Hanford Brook, St. John County, New Brunswick. Acrofxeta sagittalis transversa. 301c [Walcott, 1884a, p. 16]. (For stratigraphic position and association, see p. 132.) Middle Cambrian: Sand- stones of the St. John formation at Coldbrook, St. John Cotmty, New Brunswick. *Acrotreta sagittalis transversa. Aciotreta sp. sold [Matthew, 1895a, p. 128]. (For stratigraphic position and association, see p. 132.) Middle Cambrian: Sand- stones of Division lb5 of Matthew, on Hanford Brook, St. John County, New Brunswick. Acrothele prima costata. 301e [Matthew, 1903, p. 204]. (For stratigraphic position and association, see p. 131.) Upper Cambrian: In Division C3a of Matthew, in the St. John Basin, St. John County, New Brimswick. Lingulella cf . lepis. 301f [Matthew, 1905a, p. 128]. (For stratigraphic position and association, see p. 132.) Middle Cambrian: Sand- stones of Division lb5 of the "Protolenus zone" of Matthew, at Catons Island, in Long Reach, St. John River, Kings County, New Brimswick. Acrothele prima costata. 301g (references follow species; see 301w, 308h, and 308i). (For stratigraphic position and association, see p. 132.) Middle Cambrian: Sandstones of Division Ic of Matthew, at Portland (now part of the city of St. John), St. John Cotmty, New Brunswick. lingulella dawsoni [Matthew, 1886, p. 34]= Lingulella ferruginea. Acrothele matthewi [Matthew, 1886, p. 41]. Acrothele matthewi lata [Matthew, 1886, p. 41]. *Discinopsis gulielmi [Matthew, 1886, p. 39]. Protorthis billingsi [TJ. S. National Museum and Mat- thew, 1886, p. 44]. *Protorthis latourensis (TJ. S. National Museum). Protorthis quacoensLs [Matthew, 1886, p. 44]. Stenotheca acadica (U. S. National Museum). Eocystites primsevus (U. S. National Museum). Agnostus vir [U. S. National Museum and Matthew, 1886, p. 70]. Microdiscus dawsoni (U. S. National Museum). Paradoxides eteminicus (U. S. National Museum). Paradoxides eteminicus suricoides (U. S. National Mu- seum). Paradoxides lamellatus (U. S. National Museum). Paradoxides micmac [U. S. National Museum and Matthew, 1886, p. 81]. Ptychoparia orestes thyrsites (U. S. National Museum). Ptychoparia (Liostracus) ouangondiana (U. S. National Museum). Ptychoparia (Liostracus) tener (U. S. National Museum). Ctenocephalus matthewi (U. S. National Museum.) Ctenocephalus matthewi hispid us (U.S. National Museum). Ctenocephalus matthewi perhispidus (U. S. National Mu- seum). Ctenocephalus (Harttella) matthewi (U. S. National Mu- seum). Conocoryphe (Bailiella) baileyi (U. S. National Museum). Conocoryphe (Bailiella) baileyi arcuata (U. S. National Museum). Conocoryphe (Bailiella) elegans (U. S. National Museum), Conocoryphe (Bailiella) walcotti (U. S. National Museum). 3011i (references follow species). (For stratigraphic position and association, see p. 132.) Middle Cambrian: Shales of Division Ic of Matthew, on Hanford Brook, St. John County, New Brunswick. *Stenotheca nasuta [Matthew, 1886, p. 58]. Agnostus vir [Matthew, 1886, p. 70]. Paradoxides micmac [Matthew, 1886, p. 81]. Eocoryne geminum [Matthew, 1886, p. 31]. Lingulella dawsoni [Matthew, 1886, p. 34]= Lingulella ferruginea. Acrothele matthewi [Matthew, 1886, p. 41]. *Archseocyathus? pavonoides [Matthew, 1886, p. 30]. *Diplotheca acadica obtusa [Matthew, 1886, p. 55]. 3011. (For stratigraphic position and association, see p. 133.) Middle Cambrian: Layersof Division Ibl of Matthew, on Hanford Brook, St. John County, New Brunswick. Acrothele matthewi. 301] (references follow species). (For stratigraphic position and association, see p. 132.) Middle Cambrian: Shales of the St. John formation at Ratcliffs Millstream, St. John County, New Brunswick. Acrothele matthewi [Walcott, 1884a, p. 16]) *Protorthi-i billingsi [Walcott, 1884a, p. 18] These two species may not occur in the same bed. LOCALITIES. 231 301k (references follow species; see 308i). (For stratigraphic position and association, see p. 132.) Middle Cam- brian: St. John formation in the city of St. John, St. John County, New Brunswick. Lingula dawsoni [Walcott, 1884a, p. 15]=Lingulella ferruginea. *Acrothele matthewi [Walcott, 1884a, p. 16]. Acrotreta sagittalis transversa (U. S. National Museum). Protorthis billingsi (U. S. National Museum). Eocystites primaevus (U. S. National Museum). Hyolithes danianus (U. S. National Museum). Stenotheca acadica (U. S. National Museum). Harttia matthewi (U. S. National Museum). Agnostus acadicus (U. S. National Museum). Microdiscus pulchellus (U. S. National Museum). Microdiscus punctatus (U. S. National Museum). Paradoxides acadicus (U. S. National Museum). Paradoxides eteminicus (U. S. National Museum). Ctenocephalus matthewi (U. S. National Museum). Conocoryphe matthewi (U. S. National Museum). Conocoryphe (Bailiella) bailey i (U. S. National Museum). Conocoryphe (Bailiella) elegans 'U. S. National Museum). Ptychoparia orestes (U. S. National Museum). Ptychoparia robbi (U. S. National Museum). Ptychoparia (Liostracus) ouangondiana aurora (U. S. National Museum). Ptychoparia (Liostracus) tener (U. S. National Museum). 301 1 (references follow species). (For stratigraphic position and association, see p. 132.) Middle Cambrian: Shales on Porters Brook, St p. 34]=Lingulella 128]. of Division Id of Matthew, Lingulella dawsoni [Matthew, 1886 ferruginea. *Lingulella linguloides [Matthew, 1886, p. 34]=LingU' lella ferruginea. Acrothele matthewi [Matthew, 1886, p. 41]. Acrothele prima costata [Matthew, 1895a, p Acrotreta misera [Matthew, 1886, p. 36]. *Protospongia (?) minor distans [Matthew, 1886 Eocoryne geminum [Matthew, 1886, p. 31]. *Dendrograpsus (?) primordialis [Matthew, 1886, p *Protograpsus alatus [Matthew, 1886, p. 32]. Hyolithes (Camerotheca) danianus [Matthew, 1886, p. 50]. *HyoUthes (Camerotheca) gracilis [Matthew, 1886, p. 51]. Diplotheca acadica [U. S. National Museum and Mat- thew, 1886, p. 55]. *Diplotheca acadica sericea [U. S. National Museum and Matthew, 1886, p. 55]. *Diplotheca hyattiana caudata [U. S. National Museum and Matthew, 1886, p. 54]. p. 30]. 31]. Martins, St. John County, New Brunswick. *Stenotheca concentrica [Matthew, 1886, p. 57]. *Stenotheca hicksiana [Matthew, 1886, p. 57]. *Lepiditta curta [Matthew, 1886, p. 62]. *Agnostus acadicus declivis [U. S. National Museum and Matthew, 1886, p. 71]. *Agnostus acutilobus [U. S. National Museum and Mat- thew, 1886, p. 74]. *Agnostus obtusilobus [Matthew, 1886, p. 73]. *Agnostus tessela [U. S. National Museum and Matthew, 1886, p. 71]. *Agnostus umbo [Matthew, 1886, p. 72]. *Agnostus vir concinnus [U. S. National Museum and Matthew, 1886, p. 70]. Microdiscus punctatus pulchellus [U. S. National Museum and Matthew, 1886, p. 75]. *Paradoxides abenacus [Matthew, 1886, p. 80]. *Solenoplem'a acadica [Matthew, 1886, p. 77]. 301m (references follow species). (For stratigraphic position and association, see p. 132.) Middle Cambrian: Shale of Division Ic of Matthew's section on Porters Brook, St. Martins, St. John County, New Brunswick. Protorthis quacoensis [Matthew, 1886, p. 44]. I Hyolithes (Camerotheca) danianus [Matthew, 1886, p. 50]. *Stenotheca radiata [Matthew, 1886, p. 58]. | Eocoryne geminum (U. S. National Museum). 301n [Matthew, 1892, p. 39]. (For stratigraphic position and association, see p. 131.) Upper Cambrian: Shales of Division 3a of Matthew, on the "right shore, " below the "falls," St. John Harbor, St. John County, New Brunswick. *Lingulella Isevis. 301s [Matthew, 1894, p. 91]. Lower Ordovician: Gray sandstones of Division 3e (?) of Matthew, at McAphee's Corner, Hardingville, St. John County, New Brunswick. *Lingulella grandis. 301t [Matthew, 1903, p. 201]. (For stratigraphic position and association, see p. 131.) Upper Cambrian: Sandy shales of Division C3a of Matthew, at Carlton shore, near the suspension bridge, St. John, St. John Coimty, New Brunswick. Lingulella leevis grandis. 301u (references follow species). (For stratigraphic position and association, see p. 131.) Upper Cambrian : Shales of Division C3b of Matthew, in the St. John Basin, St. John County, New Brunswick. Lingulella cf. lepis [Matthew, 1903, p. 204]. Sphserophthalmus alatus [Matthew, 1903, p. 240]. 232 CAilBRIAN BRACHIOPODA. 301v [Matthew, 1890, p. 155]. Lower Cambrian: Sandy shales of Division 2b of the " basal series" of Matthew, on Hanford Brook, St. John County, New Brunswick. ^Rustella major. The following species were found at the same locality and approximate horizon [Walcott, 1900, p. 322]: Micromitra (Paterina) labradorica. Hyolithes of. communis. Coleoloides cf . typicalis. 301w (references follow species; see 301g, 308h, and 308i). (For stratigraphic position and association, see p. 132.) Middle Cambrian: Shales of Division lc2 of Matthew's section at Portland (now part of the city of St. John), St. John County, New Brunswick. Discinopsis gulielmi (U. S. National Museum). Acrothele matthewi (U. S. National Museum). *Protorthis latourensis [U. S. National Museum and Matthew, 1886, pp. 42 and 82]. Protorthis quacoensis (U. S. National Museum). Hyolithes (Camerotheca) micmac [Matthew, 1886, p. 81]. Stenotheca triangularis [Matthew, 1886, pp. 58 and 83]. Stenotheca (Parmophorella) acadica [Matthew, 1886, p. 60]. Agnostus regulus [Matthew, 1886, pp. 68 and 84]. Microdiscus dawsoni [Matthew, 1886, pp. 75 and 84]. Paradoxides acadicus suricus [Matthew, 1886, p. 78]. Paradoxides eteminicus (U. S. National Museum). Ctenocephalus matthewi (II. S. National Museum). Ctenocephalus matthewi hispidus (U. S. National Museum). Ptychoparia (Liostracus) ouangondiana (U. S. National Museum). Conocoryphe (Bailiella) baileyi (U. S. National Museum). Conocoryphe (Bailiella) baileyi arcuata (U. S. National Museum). Conocoryphe (Bailiella) walcotti (U. S. National Museum). 301x [Matthew, 1891, p. 148, and on label with the specimens in Matthew's collection]. (For stratigraphic posi- tion and association, see p. 131.) Middle Cambrian: Sandstones of Division C2c of Matthew, Dunns Shore, Simonds, near St. John, St. John County, New Brunswick. Lingulella radula aspera=Lingulella radula. SOly [Matthew, 1891, p. 148, and Museum of Comparative Zoology]. For stratigraphic position and association, see p. 131.) Middle Cambrian: Shaly sandstones of Division C2c of Matthew, east side of Courtney Bay, St. John, New Brunswick. *Ling;ulella radula aspera=Lingulella radula. SOlz (references follow species). (For stratigraphic position and association, see p. 132.) sion Ic of Matthew, on Ratcliffs Millstream, St. John County, New Brunswick. Middle Cambrian: Divi- Lingulella dawsoni [Matthew, 1886, p. 34]= Lingulella ferruginea. Harttia matthewi [Matthew, 1886, p. 61]. Hyolithes (Camerotheca) danianus [Matthew, 1886, p. 50]. Conocoryphe (Bailiella) elegans (U.S. National Museum). 302 [U. S. National Museum]. Middle Gallatin, Gallatin County, Mont. Micromitra pealei. ♦Micromitra sculptilis. Obolus matinalis. *Acrotreta attenuata. Cambrian: Limestone east of West Gallatin (Gallatin) River, above *Acrotreta attenuata var. Eoorthis hamburgensis. Eoorthis sp. 302a [U. S. National Museum]. Middle Cambrian: Limestones at several places on the south side of Gallatin Valley, Gallatin County, Mont. Micromitra sculptilis. Acrotreta idahoensis. 302b [U. S. National Museum]. Middle Cambrian: Limestones near Crowfoot Ridge, Gallatin quadrangle (U. S. G. S.), Yellowstone National Park, Wyo. Micromitra sculptilis. *Micromitra sp. undt. Obolus rotundatus. Lingulella desiderata. Lingulella sp. These species may not all be from the same bed or from exactly the same locality *Lingulella (Lingulepis) acuminata meeki. Dicellomus nanus. Acrotreta idahoensis. Eoorthis remnicha. 302c [U. S. National Museum]. Upper Cambrian: Shaly limestone on south side of Gallatin Valley, Yellowstone National Park, Wyo. Micromitra sculptilis. •Eoorthis iddingsi. LOCALITIES. 233 302d [U. S. National Museum]. Upper Cambrian: Limestone 200 yards (183 m.) north of the southwest comer of sec. 18, T. 28 N., R. 113 W., Uinta County, Wyo. (E. E. Smith). Obelus matinalis. Obolus sinoe. Eoorthis iddingsi. 302e [U. S. National Museum]. Upper Cambrian: Limestone near the top of the Deadwood formation in Big Popo Agie Canyon, near Lander, Fremont County, Wyo. (N. H. Darton). Eoorthis wichitaensis. 302f [U. S. National Museum]. Upper Cambrian: Upper part of the Gallatin formation, north side of Elk Pass, between Buffalo and Slough creeks, Yellowstone National Park, Livingston quadrangle (U. S. G. S.), Mont. Billingsella coloradoensis. Otusia sandbergi. 302g [U. S. National Museum]. Upper Cambrian: Limestone on the north slope of Crowfoot Bidge, south of the Gallatin Valley, Gallatin quadrangle (U. S. G. S.), Yellowstone National Park, Wyo. Billingsella coloradoensis. 302h [U. S. National Museum]. Upper Cambrian: Limestone on the divide between Panther Creek and Gallatin River, Gallatin quadrangle (U. S. G. S.), Yellowstone National Park, Wyo. Billingsella coloradoensis. 302j [U. S. National Museum records]. Lower Ordovician: Limestone on the east side of West Gallatin (Gallatin) River, above Gallatin, Gallatin County, Mont. „„, , ,, ■ . Ixhese species may not be fi'om the same exact locality. *ClarkelIa montanensis.) 302k [U. S. National Museum]. Middle Cambrian: Limestone near Gallatin, Threeforks quadrangle (U. S. G. S.), Gallatin County, Mont. Dicellomus politus. 3021 [U. S. National Museum]. Middle Cambrian: Limestone in the Gallatin Range, Yellowstone National Park, Wyo. *Lingulella desiderata. 302m [U. S. National Museum]. Middle Cambrian: Middle of shale above lower sandstone on Billy Creek, in the Bighorn Mountains, Sheridan County, Wyo. (N. H. Darton, 1902). Lingulella (Lingulepis) acuminata. Dicellomus nanus. 302n [U. S. National Museum]. Upper Cambrian: Limestone on the south side of the Gallatin Valley, Gallatin County, Mont. Eoorthis remnicha. 302o [U. S. National Museum]. Middle Cambrian: Sandstones just above the granite west of Garfield Peak, 50 miles (80.5 km.) west of Casper, Natrona Coimty, Wyo. (N. H. Darton). *Obolus (Westonia) dartoni. 302p [U. S. National Museum]. Upper Cambrian: Middle limestone of the Deadwood formation near the summit of the Owl Creek Mountains, 18 miles (29 km.) southwest of Thermopolis, Fremont County, Wyo. (N. H. Darton). Billingsella coloradoensis. Huenella abnormis. Ptychoparia. 302q [U. S. National Museum]. LTpper Cambrian: About 1,000 feet (305 m.) above the quartzitic sandstones in the " Yogo limestone (Devono-Silurian) " of W. H. Emmons [1907, p. 34], on Rock Creek, Phillipsburg quad- rangle (U. S. G. S.), Granite County, Mont. (E. M'. Kindle, 1907). Billingsella coloradoensis. 302r [U. S. National Museum]. Upper Cambrian: About 1,000 feet (305 m.) above the quartzitic sandstones in the "Yogo limestone (Devono-Silurian) " of W. H. Emmons [1907, p. 34], near Princeton, Phillipsburg quad- rangle (U. S. G. S.), Granite County, Mont. (E. M. Kindle, 1907). Obolus cf. discoideus. I Agraulos. Billingsella coloradoensis. I Anomocare. Cyrtolites. 234 CMIBRIAN BRACHIOPODA. 302s [U. S. National Museum]. Middle Cambrian: Dark siliceous shale in a quarry in Last Chance Gulch, south slope of Mount Helena, 1.5 miles (2.4 km.) south of Helena, Jefferson County, Mont. Obelus (Westonia) ella. *Lingulella helena. Dicellomus politus. 302t [U. S. National Museum]. Middle Cambrian: Limestone northeast of Logan, Threeforks quadrangle (U. S. G. S.), Gallatin County, Mont. Micromitra (Iphidella) pannula. Acrotreta sp. undt. Ptychoparia. 302u [U. S. National Museum]. LTpper Cambrian: Upper limestone of the Deadwood formation north of Cheever's ranch, on the summit of the Bighorn Mountains, Wyo. (N. H. Darton). Dicellomus nanus. 302v [U. S. National Museum]. Ordovician: Sandstones 2 miles (3.2 km.) west of the main summit, nf Buffalo Fork Peak [see St. John, 1877, pp. 468 and 469 and map opposite p. 324 (near station XLIX)], about 25 miles (40 km.) east of Jackson Lake, Uinta County, Wyo. Dicellomus nanus. 302w [U. S. National Museum]. Middle Cambrian: Limestone at Madison Mountain, Mont. Acrotreta idahoensis. Billingsella coloradoensis. 302x [U. S. National Museum]. Middle Cambrian: Sandstones near the head of Powder River, Bighorn Mountains, Wyo. (F. V. Hayden). Obolus since. 302y [U. S. National Museum]. Middle Cambrian: Sandstone on Johnson Creek, Bighorn Mountains, Wyo. (N. H. Darton, 1902). Dicellomus nanus. 302z [U. S. National Museum]. Middle Cambrian: Limestone on Mill Creek, near Landusky, Little Rocky Mountains, Chouteau County, Mont. (W. H. Weed). Dicellomus nanus. 303 [Barrande, lS79b, PI. XCV], (For stratigraphic position and association, see p. 124.) Lower Ordovician: Etage d3 at Konigshof, Bohemia, Austria-Hungary. *Acrotreta babel. 303a (references follow species). (For stratigraphic position and association, see p. 124.) Lower Ordovician: Etage d3 at Trubin, Bohemia, Austria-Hungary. Lingulella? simplex [Barrande, 1879b, PL CIV]. Acrotreta babel? [Barrande, 1879b, PL XCV]. 303b [Barrande, 1879b, PL CXXVI]. (For stratigraphic position and association, see p. 124.) Lower Ordovician: Etage dl in the environs of Rokitzan, Bohemia, Austria-Hungary. *Obolus? rokitzanensis. 303c (references follow species). (For stratigraphic position and association, see p. 124.) Passage beds between the Upper Cambrian and the Ordovician: Suburbs of Hof, Bavaria, Germany. *Obolus? bavaricus [Barrande, 1868a, p. 100]. *Obolus? minor [Barrande, 1868a, p. 105]. *Obolus? palliatus [Barrande, 1868a, p. 105]. *Lingul€lla cedens [Barrande, 1868a, p. 102]. *Lingulella? humillima [Barrande, 1868a, p. 101]. *Lingulella signata [Barrande, 1868a, p. 103]. Lingulella wirthi [Barrande, 1868a, p. 101]. *Acrotreta inchoans [BaiTande, 1868a, p. 102]. *Orbiculoidea contraria [BaiTande, 1868a, p. 104]. *Orbiculoidea varians [Barrande, 1868a, p. 103]. *Eoorthis bavarica [Barrande, 1868a, p. 99]. 303d (references follow species). (For stratigraphic position and association, see p. 124.) Lower Ordovician: Etage dl at Swarow, Bohemia, Austria-Hungary. *Obolus? advenus [Barrande, 1879b, PL XCV]. Lingulella? insons [Barrande, 1879b, PL CV]. ♦Acrotreta? minima [Barrande, 1879b, PL XCV]. LOCALITIES. 235 303e [Barrande, 1879b, PI. CV]. (For stratigraphic position and association, see p. 124.) Lower Ordovician: Etage dl at Sta. Benigna, Bohemia, Austria-Hungaiy. *LuigiilelIa? insons. 303f [Pompeckj , 1896a, pp . 7 and 8] . ( For stratigraphic position and association , see p . ] 24. ) Passage beds between the Upper Cambrian and the Ordovician: Railway cut near Schellenberg, a little distance back of the railway station at Neuhof, near Hof, Bavaria, Germany. Lingulella cedens. Lingulella? humUlima. Lingulella wirthi. Lingula n. sp. Acrotreta inchoans. Acrotreta n. sp. Orbiculoidea contraria. Orbiculoidea varians. Orthis sp.^Eoorthis bavarica. Macrocystella bavarica. Bellerophon n. sp. Bavarilla hofensis. Dikellocephalus (?) bavaricus. Niobe innotata. Niobe discrepans. 303g [Barrande, 1879b, PL CXI]. (For stratigraphic position and association, see p. 124.) Lower Ordovician: Etage dl at Rabenberg, Bohemia, Austria-Hungaiy. *Obolus? ancillus. Obolus? complexus. 3031i [Barrande, 1879b, PL XCV]. (For stratigraphic position and association, see p. 124.) Lower Ordovician: Etage dl at MUinsky Wrch, near Woleschna, Bohemia, Austria-Hungary. Obolus complexus. 303i (references follow species). (For stratigraphic position and association, see p. 124.) Lower Ordovician: Etage dl at Kruschna Hora, Bohemia, Austria-Hungary. *Obolus complexus [Barrande, 1879b, PL XCV]. *Obolus feistmanteli [Barrande, 1879b, PL CX]. 303] [Barrande, 1879b, PL CVI]. (For stratigraphic position and association, see p. 124.) Lower Ordovician: Etage dl at Czerhowitz, Bohemia, Austriar Hungary. Obolus feistmanteli. 303k [Barrande, 1879b, PL CXI]. (For stratigraphic position and association, see p. 124.) Lower Ordovician: Etage dl at Hradischt, Bohemia, Austria-Hungary. *Obolus? mirandus. 3031 [Ban-ande, 1879b, PI. CVI]. (For stratigraphic position and association, see p. 124.) Lower Ordovician: Etage dl at Libetschov, Bohemia, Austria-Hungary. *Obolus? (Westonia?) lamellosus. Lingula? eximia. 303ni [Barrande, 1879b, PL CIV]. (For stratigraphic position and association, see p. 124.) Ordovician': Etage d4 at Lieben, Bohemia, Austria-Hungary. *Lingulella davidsoni. ' 303n [Barrande, 1879b, PI. CIV]. (For stratigraphic position and association, see p. 124.) Ordovician: Etage d4 at Wraz, Bohemia, Austria-Hungary. Lingulella davidsoni. 303o [Barrande, 1879b, PI. CIV]. (For stratigraphic position and association, see p. 124.) Ordovician: Etage d4 at Lodenitz, Bohemia, Austria-Hungary. Lingulella davidsoni. 303p [Barrande, 1879b, PL CIV]. (For stratigraphic position and association, see p. 124.) Lower Ordovician: Etage d3 in the environs of Beraun, Bohemia, Austria-Hungary. *Lingulella? simplex. 304 [Matley, 1902, p. 145]. (For stratigraphic position and association, see p. 135.) Upper Cambrian: "Bronsil" shales at ■\^^lite Leaved Oak, Malvern Hills, between Herefordshire and Worcestershire, England. Acrotreta belti. 236 CAMBEIAN BEACHIOPODA. 304a [Groom, 1902, p. 110]. (For stratigraphic position and association, see p. 135.) Upper Cambrian: "Bronsil' shales, Malvern Hills, between Herefordshire and Worcestershire, England. Obelus (Broggeria) salteri. Lingulella nicholsoni. Lingulella? sp.=Acrothyra?. Lingula sp. Acrotreta belti. Acrotreta cf . nicholsoni. Acrotreta sabrinse. Acrotreta cf. socialis. Dictyonema sociale Salter. Tomaculum problematicum Groom. (?) Hyolithes assulatus Groom. Agnostus dux Callaway. Cheirurus frederiei Salter. Platypeltis croftii Callaway?. Asaphellus affinis McCoy?. Parabolinella (?) triarthrus Callaway?. Acanthopleurella grindrodi Groom. Niobe homfrayi Salter?. (?) Niobe? sp., near 0. peltata Salter. 304b [Groom, 1902, p. 109]. (For stratigraphic position and association, see p. 135.) (See 304f, the "black shales" being another name for the "'WTiite Leaved Oak shales"). Upper Cambrian: Lower part of the "MTiite Leaved Oak " shales (the zone of Polyphyma), Malvern Hills, between Herefordshire and Worcestershire, England. Micromitra pusilla. Lingulella nicholsoni (doubtfully). Acrotreta sabrinse. Polyphyma lapworthi Groom. Small ostracod. Protospongia fenestrata Salter. Plant remains (?). Agnostus sp. 304c [Groom, 1902, p. 94]. (For stratigraphic position and association, see p. 136.) Lower Cambrian: "Malvern quartzite" at Raggedstone Hill, Malvern Hills, between Herefordshire and Worcestershire, England. Micromitra (Paterina) phillipsi. I Hyolithes fistula (Holl). Obolella groomi. I Hyolithes primsevus Groom. 304d [Groom, 1902, p. 94]. (For stratigraphic position and association, see p. 136.) Lower Cambrian: "Malverrt quartzite "at Midsummer Hill, Malvern Hills, between Herefordshire and Worcestershire, England. Micromitra (Paterina) phillipsi. . _ Obolella groomi. 304e [Davidson, 1866, p. 62]. (For stratigraphic position and association, see p. 135.) Upper Cambrian: Upper part of the black "\Vhite Leaved Oak" shales at Coal Hill, east end of the Malvern Hills, between Hereford- shire and Worcestershire, England. > *Obolus (Broggeria) salteri. 304i [Salter, 1865, p. 102]. (For stratigraphic position and association, see p. 135.) (See 304b, the "black shales" being another name for the "White Leaved Oak shales. ") Upper Cambrian: " Black shales " in the Malvern Hills, between Herefordshire and Worcestershire, England. *Lingulella (Lingulepis?) pygmsea. 304g (references follow species). (For stratigraphic position and association, see p. 135.) Upper Cambrian: Sand- stones of the Hollybush series (horizon of Middle Lingula beds [Davidson, 1866, p. 63]), Malvern Hills, between Herefordshire and Worcestershire, England. *Micromitra (Paterina) phillipsi [Holl, 1865, p. 89]. *Lingulella (Lingulepis?) squamosa [Holl, 1865, p. 102]. Groom [1902, p. 109] cites the following from the "Hollybush sandstones" Micromitra phillipsi. Acrotreta sagittalis?. Hyolithes fistula (Holl). Hyolithes malvernensis Groom. Hyolithes primsevus Groom. Hyolithes, 2 or more species. Coleoloides? sp. Scolecoderma antiquissima (Salter). Modiolopsis? sp. Foraminifera (glauconitic casts). 304h [U.S. National Museum] . (For stratigraphic position and association, see p. 135.) Upper Cambrian : Shineton shales, Mary Dingle, South Shropshire, England. Acrotreta nicholsoni. *Acrotreta sabrinse. 3041 [Callaway, 1877, p. 669]. (For stratigraphic position and association, see p. 135.) Upper Cambrian: Shineton shale at Shineton, Mary Dingle, Dryton, Cressage, 1 mile (1.6 km.) west of Cressage, west of Haxley, and under Cound-Moor quarry, all in South Shropshire, England. *Lingulella nicholsoni. Acrotreta sabrinse. 304j [Mason College collections]. (For stratigraphic position and association, see p. 135.) Upper Cambrian: Lower Stockingford shales, Puxley Park Lane, halfway up the path to the quarry, Atherstone, Warwickshire, England (C. A. Matley, 1894). Acrothele intermedia?. Acrotreta sabrinse. LOCALITIES. 237 3041;: [Davidson, 1883, pp. 208 and 209]. (For stratigraphic position and association, see p. 135.) Upper Cambrian: Shineton shale at Bull Hill Cottage and Pewardine, both in South Shropshire, England. Lingulella nicholsoni. 3041 [Geol. Survey Great Britain]. (See 304p.) (For stratigraphic position and association, see p. 135.) Upper Cambrian: Shineton shales at the following localities of the Geological Survey of Great Britain: 2246, 2481, 2499, 2512, 2513, 2541, 2548, 2556, 2567, 2625, and 2627, all of which are on Shineton Brook and vicinity, South Shropshire, England. Lingulella nicholsoni. 304n [McCoy, 1854, p. 254]. (For stratigraphic position and association, see p. 135.) Ordovician: "Coniston (Bala) limestone " at Coniston, Lancashire, England. Lingulella davisi. 3040 [U. S. National Museum]. (For stratigraphic position and association, see p. 136.) Lower Cambrian: Sand- stone at Nuneaton, England. Micromitra (Paterina) labradorica. 304p [Geol. Survey Great Britain]. (See 3041.) (For stratigraphic position and association, see p. 135.) Upper Cambrian: Shineton shales at the following localities of the Geological Survey of Great Britain: 2495, 2536, 2543, 2545, 2558, and 2580, all of which are on Shineton Brook, South Shropshire, England (Chaa. Lapworth). Acrotreta sabrinae. 305 [Davidson, 1871, p. 341]. (For stratigraphic position and association, see p. 135.) Upper Cambrian: Lower Tremadoc shales, Craig-y-dinas, North Wales. *Acrotreta belti. 305a [Davidson, 1866, desc. of PI. III]. (For stratigraphic position and association, see p. 135.) Upper Cambrian: Upper Tremadoc beds at Moel-y-gest, northwest side, Carnarvonshire, North Wales. Lingulella lepia. 305c. (For stratigraphic position and association, see p. 135.) Upper Cambrian: Lower Tremadoc slate, every- where in the Tremadoc district, Carnarvonshire, North Wales. Lingulella lepis. 305d [Davidson, 1866, p. 54]. (For stratigraphic position and association, see p. 135.) Upper Cambrian: In the Upper Lingula flags near Tremadoc, Carnarvonshire, North Wales. Lingulella lepis?. 305e [Davidson, 1866, p. 54]. (For stratigraphic position and association, see p. 135.) Upper Cambrian: Upper Tremadoc beds near Tai-hirion, Arenig, North Wales. Lingulella lepis. 305f [Davidson, 1866, p. 54]. (For stratigraphic position and association, see p. 135.) Upper Cambrian: Lower Tremadoc beds east of Pont Nant-y-Ladron, on the Bala road from Ffestiniog, Merionethshire, North Wales. Lingulella lepis. 305g [Davidson, 1866, p. 54]. (For stratigraphic position and association, see p. 135.) Upper Cambrian: Lower Tremadoc at Wern, North Wales. Lingulella lepis. 305h [Davidson, 1866, p. 54]. (For stratigraphic position and association, see p. 135.) Upper Cambrian: Lower Tremadoc at Borthwood, North Wales. *Lingulella lepis. 3051 [Davidson, 1866, p. 54], (For stratigraphic position and association, see p. 135.) Upper Cambrian: Lower Tremadoc at Trwyn-y-Iago, North Wales. Lingulella lepis. 305] [Davidson, 1866, p. 54]. (For stratigraphic position and association, see p. 135.) Upper Cambrian: Lower Tremadoc at Cefn Cyfarnedd, North Wales. Lingulella lepis. 306 [Geol. Survey Canada]. Upper? Cambrian: Sandy limestone on Gravel River, eastern slope of the Rocky Mountains, in the Mackenzie basin, British Columbia (J. Keele, 1908). Billingsella coloradoensis. Eoorthis desmopleura?. 238 CMIBKIAN BRACHIOPODA. 307 (references follow species). (For stratigraphic position and association, see p. 131.) of Di\asion C3c of Matthew on McLeod Brook (=Barachois River), Cape Breton Upper Cambrian: Shales Nova Scotia. Obolus refulgens [Matthew, 1903, p. 213]. *Lingulella concinna [Matthew, 1903, p. 204]. Leptobolus gemmulus [Matthew, 1903, p. 192]=Lingulella ferruginea. Leptobolus cf. linguloides [Matthew, 1903, p. 193]=Lingu- lella ferruginea. Linnarssonia cf. belt! [Matthew, 1903, p. 210]. *Acrotreta bisecta [Matthew, 1903, p. 187]. *Schizambon priscus [Matthew, 1903, p. 188]. 307a (references follow species). (For stratigraphic position and association, see p. 131.) Upper Cambrian: Shales of Division C3c2 of Matthew [1903, p. 240], on McLeod Brook (=Barachois River), near Boisdale, eastern Cape Breton, Nova Scotia. *Lingulella cf. daA-isi [Jlatthew, 1903, p. 203]. *Lingulella cf. lepis [Matthew, 1903, p. 240]. Lingulella cf. linguloides [Matthew, 1903, p. 240]=Lingu- lella ferruginea. Acrotreta sipo [Matthew, 1903, p. 186]=Acrotreta bisecta. *Urotheca sp. [Matthew, 1903, p. 183]. *ModioIopsis? cf. solvensis [Matthew, 1903, p. 217]. *Bellerophon bretonensis [Matthew, 1903, p. 218]. *Bellerophon insulse [Matthew, 1903, p. 217]. *Bellerophon semisculptus [Matthew, 1903, p. 219]. *Parabolinella? cf. limitis [Matthew, 1903, p. 226]. *Parabolinella? quadrata [ilatthew, 1903, p. 226]. *Triarthrus belli [Matthew, 1903, p. 231]. *Angelina? sp. []\Iatthew, 1903, p. 232]. *Asaphellus homfrayi var. [Matthew, 1903, p. 235]. *Asaphellus? planus [Matthew, 1903, p. 238]. 307b [U. S. National Museum]. (For stratigraphic position and association, see p. 131.) stone on McPhees Brook, Cape Breton, Nova Scotia. Lingulella radula. Middle Cambrian: Sand- 307c [Matthew, 1903, p. 205]. (For stratigraphic position and association, see p. 131.) Middle Cambrian: Sand- stones probably belonging with Division C2c of Matthew, on Mira River, eastern Cape Breton, Nova Scotia. Lingulella radula. 307d (references follow species). (For stratigraphic position and association, see p. 134.) Middle Cambrian: Sandy limestone of Division E2a? of Matthew's Etcheminian on Young (McFees) Point [Matthew, 1903, p. 19], near George River station. Cape Breton, Nova Scotia. *Obolus sequiputeis [Matthew, 1903, p. 140]=Obolus sel- wyni. '^Obolus selwyni [Matthew, 1903, p. 123]. *Lingulella atava insulas [Matthew, 1903, p. 110]. Obolus discus [Matthew, 1903, p. 79]= Lingulella triparilis. *Lingulella (Lingulepis) roberti [Matthew, 1903, p. 132]. Acrotreta sp. [Matthew, 1903, p. 96]. *Billingsella retroflexa [Matthew, 1903, p. 149]. *Hyolithes cf. tenuistriatus [Matthew, 1903, p. 83]. *Pai-adoxidoid trilobite [Matthew, 1903, p. 176]. *Holasaphus centropyge [Matthew, 1903, p. 176]. *Eurypterid (?) crustacean [Matthew, 1903, p. 79]. 307e [JIatthew, 1903, p. 216]. (For stratigraphic position and association, see p. 131.) Upper Cambrian: Lime- stone in Division C3b? (possibly C3c) on Gillis Brook, eastern Cape Breton, Nova Scotia. Orusia lenticularis. 307f [Matthew, 1903, p. 198]. (For stratigraphic position and association, see p. 132.) Middle Cambrian: Shales of Division C2a on McLean Brook, Mira River, Cape Breton, Nova Scotia. Lingulella (Lingulepis) exigua. 307g (references follow species). (For stratigraphic position and association, see p. 132.) Middle Cambrian: Shales of Division C2b on McLean Brook, above Marion Bridge, Mira River, Cape Breton, Nova Scotia. Lingulepis starri var. [Matthew, 1903, p. 195]=Lingulella (Lingulepis) exigua. Lingulepis starri exigua [ilatthew, 1903, p. 198]= Lingulella (Lingulepis) exigua. Beyrichia triceps [Matthew, 1903, p. 220]. 307h [Matthew, 1903, p. 216]. (For stratigraphic position and association, see p. 131.) Upper Cambrian: In Divi- sion C3b? (possibly C3c) on McLeod Brook (=Barachois River), eastern Cape Breton, Nova Scotia. Orusia lenticularis. 3071 (references follow species) Division C3b of Matthew Orusia lenticularis [Matthew, 1903, p. 216]. *Agnostus acadicus cf. declivis [Matthew, 1903, p Agnostua trisectus? [Matthew, 1903, p. 223]. (For stratigraphic position and association, see p. 131.) Upper Cambrian: In section on McNeil Brook, east of Mira River, eastern Cape Breton, Nova Scotia. Sphserophthalmus alatus [Matthew, 1903, p. 229]. 223]. Peltura scarabseoides [Matthew, 1903, p. 223]. Ctenopyge lobata? [Matthew, 1903, p. 223]. LOCALITIES. 239 307j (references follow species). (For stratigraphic position and association, see p. 131.) Upper Cambrian: Lime- stone in Division C3b? (possibly C3c), on East Bay, east of Bras d'Or Lake, eastern Cape Breton, Nova Scotia. Orusia lenticularis [Matthew, 1903, p. 216]. *Agnostus trisectus germanus [Matthew, 1903, p. 221]. *Agnostus cf. cyclopyge [Matthew, 1903, p. 222]. Tarabolina dawsoni [Matthew, 1903, p. 224]. Ctenopyge pecten [Matthew, 1903, p. 230]. 308 (references follow species). (For stratigraphic position and association, see p. 131.) LTpper Cambrian: Shales of Division C3c of Matthew, at Navy Island, St. John Harbor, New Brunswick. • Schizambon prisons [Matthew, 1901a, p. 278]. Acrotreta baileyi [Matthew, 1892, p. 43]=Acrotretabisecta. *Linnarssonia beiti? [Matthew, 1892, p. 42]. *Obolus refulgens [Matthew, 1892, p. 45]. *Obolella gemmula [Matthew, 1892, p. 41]=Lingulella ferruginea. 308a [Matthew, 1893b, p. 103]. (For stratigraphic position and association, see p. 131.) Upper Cambrian: Dark shales of Division C3a of Matthew's section of the St. John terrane. Navy Island, St. John Harbor, St. John County, New Brunswick. *Eoorthis atava. 308b (references follow species). (For stratigraphic position and association, see p. 131.) Upper Cambrian: Lime- stone lentiles in black shales of Division C3a of Matthew's section, Germaine Street, St. John, St. John County, New Brunswick. Orusia lenticularis [Matthew, 1892, p. 48]. *Orusia lenticularis atrypoides [Matthew, 1892, p. 48[ *Orusia lenticularis lyncioides [Matthew, 1892, p. 48]. *Eoorthis johannensis [Matthew, 1892, p. 49]. Parabolina spinulosa [Matthew, 1892, p. 51]. Protopeltura acanthura tetracanthura [Matthew, 1892, p. 53]. Conocephalites contiguus [Matthew, 1892, p. 58]. 308e [Matthew, 1891, p. 147]. (For stratigraphic position and association, see p. 132.) ITpper Cambrian: Shales of Division 2b of Matthew's Johannian at St. John, St. John County, New Brunswick. *Lingulella (Lingulepis) stan-i. 308d [Matthew, 1894, p. 121]. (For stratigraphic position and association, see pp. 132 and 133.) Middle Cam- brian: Sandstones of Division Clb2-4 of Matthew's section on Catons Island, in Long Reach, St. John River, Kings County, New Brunswick. *Bofsfordia pulchra. 308e [Matthew, 1895a, p. 126]. (See 2f and 2g.) (For stratigraphic position and association, see p. 133.) Middle Cambrian: Beds of Division Clbl of the " Protolenus zone" [Matthew, 1895a, p. 108], on Hanford Brook, St. John County, New Brunswick. Botsfordia cselata. 308f (references follow species). (For stratigraphic position and association, see p. 131.) Upper Cambrian: Lime- stone lentiles in black shales of Division C3a of Matthew's section. King Street, St. John, St. John County, New Brunswick. Orusia lenticularis [Matthew, 1903, p. 216]. Ctenopyge pecten [Matthew, 1903, p. 229]. 308g [Matthew, 1897, p. 71]. (See 2u.) (For stratigraphic position and association, see p. 132.) Middle Cam- brian: Shales of Division lb3 or lb4 of Matthew's section on Long Island [Matthew, 1898, pp. 124 and 127], Kennebecasis Bay, St. John County, New Brunswick. *Trematobolus kempanum. 30811 [U. S. National Museum]. (See 301g, 301w, and 308i.) (For stratigraphic position and association, see p. 132.) Middle Cambrian: Shales of Division Icl of Matthew's section at Portland (now part of the city of St. John), St. John County, New Brunswick. Discinopsis gulielmi. Acrothele matthewi. Protorthis bUlingsi. Protorthis latourensis. Eocystites primaevus Billings. Hyolithes micmac Matthew. Microdiscus dawsoni Hartt. Paradoxides eteminicus Matthew. Paradoxides lamellatus Hartt. Paradoxides micmac. Ctenocephalus matthewi perhispidus. Ptychoparia (Liostracus) tener (Hartt). 3081 [U. S. National Museum]. (See 301g, 301k, 301w, and '308h.) For stratigraphic position and association, see p. 132.) Middle Cambrian: Shales in Portland (now a part of the city of St. John), St. John County, New Brunswick. Protorthis billingsi. Paradoxides ep. 240 CAMBRIAN BRACHIOPODA. 309 (references follow species). (For stratigraphic position and association, see p. 144.) Passage beds between the Cambrian and Ordovician: Ceratopyge limestone (zone 4 of Moberg and Segerberg) at FogeMng, 5 miles (8 km.) east of Lund, Province of Malmohus, Sweden. Obolus (Broggeria) salteri [Moberg and Segerberg, 1906, desc. of PL I]. Lingula? producta [Moberg and Segerberg. 1906, p. 63]= L;ngulella lepis. Lingula? ordo^dcensis [Moberg and Segerberg, 1906. p. 63]=Lingulella lepis. *Acrotreta carinata [Moberg and Segerberg, 1906, desc. of PI. III]. *Acrotreta cu-cularis [Moberg and Segerberg, 1906, p. 66]. Obolella fAcrotreta?) sagittalis [Moberg and Segerberg, 1906, desc. of PL I]=Acrotreta sagittalis. Capulus ceratopygarum [Moberg and Segerberg, 1906, desc. of PL III]. Agnostus sidenbladhi urceolatus [Moberg and Segerberg, 1906, desc. of PL IV]. Agnostus fossulatus [Moberg and Segerberg, 1906, desc. of PL lY]. Euloma ornatum [Moberg and Segerberg, 1906, desc. of PI. nn. Hai'pides rugosus [Moberg and Segerberg, 1906, desc. of PL V]. Ceratopyge latelimbata [Moberg and Segerberg, 1906, desc. ofPl.'v]. Symphysurus angustatus [Moberg and Segerberg, 1906, desc. "of PL V]. Symphysurus elongatus [Moberg and Segerberg, 1906, desc. of PL V]. Nileus armadillo [Moberg and Segerberg, 1906, desc. of PL VI]. Niobe insignis angustifrons [Moberg and Segerberg, 1906, desc. of PL VI]. Niobe laeviceps [Mol)erg and Segerberg, 1906, dose, of PL VI]. Megalaspis intacta [Moberg and Segerberg, 1906, desc. of PL VI]. Orometopus elatifrons [Moberg and Segerberg, 1906, desc. of PL VII]. Cyi'tometopus sp. [Moberg and Segerberg, 1906, desc. of PL VII]. Harpina (Harpes) excavata? [Moberg and Segerberg, 1906, desc. of PL VII]. Crossoura parvula [Moberg and Segerberg, 1906, desc. of PL VII]. 309a [Moberg and Segerberg, 1906, p. 621. (For stratigraphic position and as.sociation, see p. 145.) Upper Cambrian: Bryograpius slate (zone 2) at Fogelsang, 5 miles (8 km.) east of Lund, Province of Malmohus, Sweden. Lingulella lepis. Lingula? bryograptorum=I/ingulella lepis. 309b [Moberg and Segerberg, 1906, p. 63]. (For stratigraphic position and association, see p. 145.) Upper Cambrian: Dictyograptus slate (zone 1) at Flagabro, Province of Malmohus, Sweden. Lingula? corrugata= Lingulella lepis. 309c [Linnarsson, 1869a, p. 357; and U. S. National Museum]. (For stratigraphic position and association, see p. 146.) Lower Cambrian: "Fucoid sandstone" at Billingen, east of Skara, Province of Skaraborg, Sweden. Obolella (Glyptias) favosa. 309d [Linnarsson, 1869a, p. 357]. (For stratigraphic po.sition and association, seep. 146.) Lower Cambrian : "Fucoid sandstone" at Lugnas, 23 miles (37 km.) northeast of Skara, Province of Skaraborg, Sweden. *Obolella (Glyptias) favosa. 309e [U. S. National Museum]. (For stratigraphic position and association, see p. 145.) Upper Cambrian: Shales of the Acerocare zone at Akarpsmolla, midway between KS.ger6d and Rostanga, Province of Malmohus, Sweden (J. C. Moberg). Eoorthis christiaDise. 309f [U. S. National Museum]. (For stratigraphic position and association, see p. 146.) Middle Cambrian: Shale at Borgholm, Oeland Island, Sweden. Acrothele (Redlichella) granulata. 309h [U. S. National Museum]. (For stratigraphic position and association, see p. 145.) Upper Cambrian: Lime- stones of the Dictyograptus Jlabelliformis zone at Fogelsang, 5 miles (8 km.) east of Lund, Province of Malmohus, Sweden, Obolus (Broggeria) salteri. 3091 [U. S. National Museum]. (See 390g.) (For stratigraphic position and association, see p. 145.) Upper Cambrian: Limestones at Sandby, 6 miles (9.6 km.) east-northeast of Lund, Province of Malmohus, Sweden. Obolus (Broggeria) salteri. 309j [U. S. National Museum]. (See 309m and 320q.) (For stratigraphic position and association, see p. 145.) Upper Cambrian: Shale at Alunbruk (alum works), southern part of Oeland Island, Sweden. Obolus (Broggeria) salteri. 3091 [U. S. National Museum], (See 310h,) (For stratigraphic position and association, see p, 145.) Upper? Cambrian: Shale collected somewhere in Sweden, exact locality unknown. Obolus (Broggeria) salteri. LOCALITIES. 241 309m [U. S. National Museum]. (See309j.) (For stratigraphic position and association, see p. 145.) Upper Cam. brian: Limestones forming 3c of the Olenus series at Alunbruk (alum -works), southern part of Oeland Island, Sweden (Schmalensee, 1899). Orusia lenticularis. 310 (references follow species). (For stratigraphic position and association, see p. 144.) Passage beds between the Upper Cambrian and the Ordovician: Ceratopyge limestone (zone 4 of Moberg and Segerberg), Ottenby, Oeland Island, Sweden. Lingula producta [Moberg and Segerberg, 1906, p. 63]= Lingulella lepis. Lingula ordovicensis [Moberg and Segerberg, 1906, p. 63]= Lingulella lepis. Acrothele barbata [Moberg and Segerberg, 1906, p. 67]= Acrothele ceratopygarum. "Acrotreta circularis [Moberg and Segerberg, 1906, p. 66]. Acrotreta carinata [Moberg and Segerberg, 1906, p. 66]. Eoorthis christianise [Moberg and Segerberg, 1906, desc. of PI. III]=Eoorthis daunus. Eostrophomena elegantula [Moberg and Segerberg, 1906, desc. of PI. III]. Lamanskya splendens [Moberg and Segerberg, 1906, desc. of PL III]. Meristella difformis [Moberg and Segerberg, 1906, desc. of PI. III]. Agnostus sidenbladhi urceolatus [Moberg and Segerberg, 1906, desc. of PI. IV]. Agnostus trinodus [Moberg and Segerberg, 1906, desc. of PI. IV]. Triarthrus angelini [Moberg and Segerberg, 1906, desc. of PI. IV]. Acerocare n. sp.? [Moberg and Segerberg, 1906, desc. of PI. IV]. Ceratopyge forficula [Moberg and Segerberg, 1906, desc. of PI. V]. Dikellocephalus broggeri [Moberg and Segerberg, 1906, desc. of PI. V]. Apatocephalus serratus [Moberg and Segerberg, 1906, desc. of PL V]. Symphysurus angustatus [Moberg and Segerberg, 1906, desc. of PL V]. Symphysm-us breviceps [Moberg and Segerberg, 1906, desc. of PL V]. NUeus armadillo [Moberg and Segerberg, 1906, desc. of PL VI]. Niobe insignis [Moberg and Segerberg, 1906, desc. of PL VI]. Niobe leeviceps [Moberg and Segerberg, 1906, desc. of PL VI]. Niobe obsoleta [Moberg and Segerberg, 1906, desc. of PL VI]. Megalaspis planilimbata [Moberg and Segerberg, 1906, desc. of PL VII]. Illsenus oriens [Moberg and Segerberg, 1906, desc. of PL VII]. Orometopus elatifrons? [Moberg and Segerberg, 1906, desc. of PL VII]. Holometopus tomquisti [Moberg and Segerberg, 1906, desc. of PL VII]. Cyixometopus primigenus [Moberg and Segerberg, 1906, desc. of PL VII]. Cyrtometopus speciosus [Moberg and Segerberg, 1906, desc. of PL VII]. 310a [U. S. National Museum]. (For stratigraphic position and association, see p. 145.) Upper Cambrian: Shales of Olenus truncatus zone, Oeland Island, Sweden. *Acrotreta conula. Orusia lenticularis. Olenus truncatus Brmm. 310b [U. S. National Museum]. (For stratigraphic position and association, see p. 145.) Middle Cambrian: Dark- brown limestone at Borgholm, Oeland Island, Sweden. Acrotreta schmalenseei. ) mi_ ^ • v. • ^.i, „ u j _.,,. „ ^ i These two species may not occur m the same bed. Billingsella exporrecta. J 310o [Wallerius, 1895, p. 66]. (See 310p.) (For stratigraphic position and association, see p. 146.) Middle Cam- brian: Limestone of the Paradorides celandicus zone on Oeland Island, Sweden. Acrotreta schmalenseei. 310d [U. S. National Museum]. (See 390i.) (For stratigraphic position and association, see p. 145.) Upper Cam- brian: Ceratopyge slate at Borgholm, Oeland Island, Sweden (Schmalensee, 1899). Obolus (Broggeria) salteri. Lingulella ferruginea. Lingulella lepis. *Acrothele borgholmensis. Acrotreta seebachi. Eoorthis christianise. Orthoid. 310e [Moberg, 1892b, p. 115]. (For stratigraphic position and association, see p. 146.) Lower Cambrian: Sandstone bowlder on the beach between Ekerum and Stora Ror, on Oeland Island, Sweden. *Acrothele sp. undt. 62667°— VOL 51. pt 1—12 16 242 CiMIBRIAN BRACHIOPODA. SlOf [lloberg, 1892b, p. 115]. (For stratigraphic position and association, see p. 146.) Lower Cambrian: Drift- blocks of glauconitic quartzitic sandstone west of Ekerum, Kalmar sheet (Geol. Survey Sweden), Oeland Island, Sweden. Micromitra (Paterina) undosa. Acrothele sp. undt. Discinella. 310g [Moberg, 1892b, p. 115]. (For stratigraphic position and association, see p. 146.) Lower Cambrian: Sand- stone bowlders south of Stora Kor, on Oeland Island, Sweden. Acrothele sp. undt. 310h [U. S. National Museum]. (See 3091.) (For stratigraphic position and association, see p. 145.) Upper?' Cambrian: Shale collected somewhere (probably Fogelsang) in the old Province of Skane, now the Provinces^ of Malmohus and Christianstad, Sweden. Lingulella concinna. Obolus (Broggeria) salteri. , Billingsella exporrecta. 3101 [U. S. National Museum]. (For stratigraphic position and association, see p. 145.) Passage beds between the Middle Cambrian Paradoxides forchharmneri zone and the Upper Cambrian Olenus truncatus zone: Limestone at Borgholm, Oeland Island, Sweden. *Lingulella agnostorum. 1 Acrotreta parvula. Acrothele coriacea. I Agnostus Isevigatus Dalman. aiOj [U. S. National Museum]. (For stratigraphic position and association, see p. 144.) Passage beds between the^ Upper Cambrian and the Ordovician: Ceratopyge limestone at Borgholm, Oeland Island, Sweden. Lingulella lepis. I Eoorthis wimani. Eoorthis daunus. I *Eostrophomena elegantula. 310k [U. S. National Museum]. (Forstratigraphicpositionandassociation, see p. 145.) Upper Cambrian: Oeland Island, Sweden. ♦Lingulella sp. undt. a. 3101 [U. S. National Museum]. (See 8w, 320f, and 321y.) (For stratigraphic position and association, seep. 145.)' Middle Cambrian: In the Paradoxides forchhammeri zone at Andrarum, 20 miles (32 km.) northwest of Sim- rishamn. Province of Christianstad, Sweden. *Dicellomus sp. undt. 310m [LinnarsEon, 1876, p. 16]. (See 310o.) (For stratigraphic position and association, see p. 146.) Middle- Cambrian: Arenaceous shales of the Paradoxides tessini zone on Oeland Island, Sweden. Lingulella ferruginea. 310n [Moberg and Segerberg, 1906, p. 65]. (For stratigraphic position and association, see p. 145.) Upper Cam- brian: In the "Obolus sandstone?" in Dalarne, Province of Kopparberg, Sweden. Obolus triangularis. 3100 [U. S. National Museum]. (See 310m.) (For stratigraphic position and association, see p. 146.) Middle Cambrian: Limestone in the Paradoxides tessini zone at Borgholm, Oeland Island, Sweden. Lingulella ferruginea. Acrothele (Redlichella) granulata. 310p (references follow species). (See 310c.) (For stratigraphic position and association, see p. 146.) Middle Cain_ brian: Limestone of the Paradoxides a,landicus zone at Borgholm, Oeland Island, Sweden. Lingulella ferruginea (U. S. National Museum). Acrotreta socialis [Linnarsson, 1876, p. 18]=Acrotreta schmalenseei. 310q [U. S. National Museum]. (For stratigraphic position and association, see p. 145.) Middle Cambrian: Lime- stone of the Agnostits Issvigalus zone at Lovened, Province of Skaraborg, Sweden. Lingulella ferruginea. 310r [Westergard, 1909, p. 76]. (For stratigraphic position and association, see p. 145.) Upper Cambrian: Zone v of the Ceratopyge slate at Ottenby, Oeland Island, Sweden. ♦Acrotreta celandica. 310s [Westerg&rd, 1909, p. 76]. (For stratigraphic position and association, see p. 145.) Upper Cambrian: Upper, most part of the Alum slate in beds equivalent to the Ceratopyge slate, northern part of Oeland Island, Sweden. Acrotreta celandica. LOCALITIES. 243 Slot [Westerg^rd, 1909, p. 57]. (For stratigraphic position and association, see p. 145.) Upper Cambrian: Sub- zone c of the Dictyograptus slate at Fogelsang, 5 miles (8 km.) east of Lund, Province of Malmohus, Sweden. *Acrotreta sp. undt. 310u [Westerg^rd, 1909, p. 77]. (For stratigraphic position and association, see p. 145.) Upper Cambrian: Sub- zone c of the Dictyograptus slate at Jerrestad, Province of Malmohus, Sweden. Acrotreta sp. 310v [Westerg^rd, 1909, p. 77]. (For stratigraphic position and association, see p. 145.) Upper Cambrian: Sub- zone 6 of the Dictyograptus slate at Tosterup, 7.5 miles (12 km.) north-northeast of Ystad, Province of Malmohus, Sweden. Acrotreta sp. 310w [Westerg^rd, 1909, desc. of PL II]. (For stratigraphic position and association, see p. 144.) Passage beds between the Upper Cambrian and the Ordovician: Zone c at Gronhogen, Oelaad Island, Sweden. Lingulella lepis. SlOx [Westergird, 1909, p. 76]. (For stratigraphic position and association, see p. 144.) Passage beds between the Upper Cambrian and the Ordovician: The uppermost limestone stratum lq beds equivalent to the Ceratopyge limestone at Jerrestad, Province of Malmohus, Sweden. *Obolus? infiatus. 310y [Linnarsson, 1879, p. 25, and U.S. National Museum.] (For stratigraphic position and association, see p. 145.) Middle Cambrian: Limestone at Kiviks Esperod, Province of Malmohus, Sweden. Lingulella ferrugiuea. SlOz [U. S. National Museum]. (For stratigraphic position and association, see p. 145.) Middle Cambrian: Lime- stone at Brantevik, on the shore a little south of Simrishamn, Province of Christianstad, Sweden. Lingulella ferruginea. Billingsella exporrecta. 311 [TV'iman, 1902, p. 57]. (For stratigraphic position and association, see p. 146.) Middle? Cambrian: Drift bowlder of coarse-grained, somewhat fi-iable, glauconitic sandstone, No. 3, on Eggegrund Island, about 25 miles (40 km.) northeast of Gefle, Province of Gefleborg, Sweden. *Obolus (Westonia) bottnicus. Lingula sp. Kutorgina?. *Acrotreta eggegrundensis. Aparchites? anderssoni. Hipponicharion matthewi. Torellella laevigata. Olenellus?. 311a [Wiman, 1902, p. 57]. (For stratigraphic position and association, see p. 146.) Middle? Cambrian: Drift bowlder of glauconitic sandstone at Norrskedika, a little northwest of Osthammar, Province of Stockholm, Sweden. Acrotreta eggegrundensis. 311b [Wiman, 1902, p. 57]. (For stratigraphic position and association, see p. 146.) Middle? Cambrian: Drift bowlder of bituminous sandstone. No. 2, on Biludden, about 20 miles (32.2 km.) east of Gefle, Province of Gefleborg, Sweden. *Acrotreta uplandica. 311o [Wiman, 1902, p. 57]. (For stratigraphic position and association, see p. 146.) Middle? Cambrian: Drift bowlder of bituminous sandstone. No. 7, on Biludden, about 20 miles (32.2 km.) east of Gefle, Province of Gefleborg, Sweden. *Obolus (Westonia) wimani. Lingula or Lingulella. Torellella laevigata. Beyrichona gevalensis. Olenellus sp. 311d [Wiman, 1902, p. 57]. (For stratigi-aphic position and association, see p. 146.) Middle? Cambrian: Drift bowlder of glauconitic sandstone south of Lumparstrommen, Aland Island, Finland, Russia. Acroti'eta eggegrundensis. 311e [Wiman, 1902, p. 57]. (For stratigraphic position and association, see p. 146.) Middle? Cambrian: Drift bowlder of rusty sandstone south of Lumparn, parish of Jomala, Aland Island, Finland, Russia. Mickwitzia monilifera. Obelus (Westonia) bottnicus?. ailf [Wiman, 1902, p. 57]. (For stratigraphic position and association, see p. 146.) Middle ? Cambrian: Drift bowlder of gray quartzitic sandstone at Slemmern, Mariehamn, Aland Island, Finland, Russia. Mickwitzia monilifera. 2-1:4 CMIBRIAN BRACHIOPODA. Sllg [Wiman, 1902, p. 57]. (For stratigraphic position and association, see p. 146.) Middle? Cambrian: Drift bowlder of bituminous sandstone, No. 16, on Biludden, about 20 miles (32.2 km.) east of Gefle, Province of Gefleborg, Sweden. Obolua (Westonia) wimani. Lingula 8p. Torellella laevigata . 31111 [^^man, 1902, p. 57]. (For stratigraphic position and association, see p. 146.) Middle? Cambrian: Drift bowlder of bituminous sandstone, No. 26, on Biludden, about 20 miles (32.2 km.) east of Gefle, Province of Gefleborg, Sweden. *Obolus (Westonia) balticus. 311i fWiman, 1902, p. 57]. (For stratigraphic position and association, see p. 146.) Middle? Cambrian: Drift bowlder of bituminous sandstone, No. 27, on Biludden, about 20 miles (32.2 km.) east of Gefle, Province of Gefleborg, Sweden. Obolus (Westonia) wimani. 311j [Wiman, 1902, p. 57]. (For stratigraphic position and association, see p. 146.) Middle? Cambrian: Drift bowlder of bituminous sandstone. No. 28, on Biludden, about 20 miles (32.2 km.) east of Gefle, Province of Gefleborg, Sweden. Obolus (Westonia) alandensis. Lingula or Lingulella. 311k [Wiman, 1902, p. 57]. (For stratigraphic position and association, see p. 146.) Middle? Cambrian: Drift bowlder of bituminous sandstone, No. 29, on Biludden, about 20 miles (32.2 km.) east of Gefle, Province of Gefleborg, Sweden. Obolus (Westonia) alandensis. Torellella laevigata. 3111 [Wiman, 1902, p. 57]. (For stratigraphic position and association, see p. 146.) Middle? Cambrian: Drift bowlder of bluish calcareous sandstone. No. 31, on Biludden, about 20 miles (32.2 km.) east of Gefle, Province of Gefleborg, Sweden. *Mickwitzia formosa. Mickwitzia monilifera. 311m [Wiman, 1902, p. 57]. (For stratigraphic position and association, see p. 146.) Middle? Cambrian: Drift bowlder of bituminoiis sandstone, No. 1, on Limon Island, about 12 miles (19.3 km.) east-northeast of Gefle, Province of Gefleborg, Sweden. Obolus (Westonia) alandensis. Beyrichona alta. Torellella laevigata. 311n [Wiman, 1902, p. 57]. (For stratigraphic position and association, see p. 146.) Middle? Cambrian: Drift bowlder of blue calcareous sandstone, No. 6, on Limon Island, about 12 miles (19.3 km.) east-northeast of Gefle, Province of Gefleborg, Sweden. Ellipsocephalus sp. Trilobite (not Olenellus). *Acrotreta uplandica limoensis. Acrotreta sp. Torellella laevigata. 3110 [Wiman, 1902, p. 57]. (For stratigraphic position and association, see p. 146.) Middle? Cambrian: Drift bowlder of bituminous sandstone, No. 1, on Skalstenarne Island, just west of Eggegrund Island, about 25 miles (40 km.) east-northeast of Gefle, Province of Gefleborg, Sweden. Obolus (Westonia) balticus. 311p [Wiman, 1902, p. 57]. (For stratigraphic position and association, see p. 146.) Middle? Cambrian: Drift bowlder of glauconitic sandstone. No. 1, at Hoganas, parish of Borstil, east of Osthammar, Province of Stockholm, Sweden. Lingiila or Ijingulella. Acrotreta uplandica. 3115 [Wiman, 1902, p. 57]. (For stratigraphic position and association, see p. 146.) Middle? Cambrian: Drift bowlder of gray quartzitic sandstone at Yttemaset, Mariehamn, Aland Island, Finland, Eussia. Mickwitzia monilifera. ailr [Wiman, 1902, p. 57]. (For stratigraphic position and association, see p. 146.) Middle? Cambrian: Drift bowlder of gray quartzitic sandstone at Granboda, Lemland, Aland Island, Finland, Eussia. Mickwitzia monilifera. LOCALITIES. 245 311s [Wiman, 1902, p. 57]. (Bot stratigraphic position and association, see p. 146.) Middle? Cambrian: Drift bowlder of gray quartzitic sandstone at Skarpn&to, Aland Island, Finland, Russia. Mickwitzia formosa. Stenotheca sp. 311t [Wiman, 1902, p. 57]. (For stratigraphic position and association, seep. 146.) Middle? Cambrian: Drift bowlder of mottled calcareous sandstone at Ofverby, parish of Jomala, Aland Island, Finland, Russia. Obelus (Westonia) balticus. I Lingula or Lingulella. Obolus (Westonia) wimani. | Ellipsocephalus latus. 311u [Wiman, 1902, p. 57]. (For stratigraphic position and association, see p. 146.) Middle? Cambrian: Drift bowlder of blue calcareous sandstone at Soderarm lighthouse, near Norrtelje, Province of Stockholm, Sweden. Mickwitzia monilifera. 3Hv [Wiman, 1902, p. 68]. (For stratigraphic position and association, see p. 145.) Upper Cambrian: Drift bowlder of Obolus sandstone, Ersholmen Island, parish of Borstil, southeast of Oregrund, Province of Stockholm, Sweden. Obolus apoUinis. 311w [Wiman, 1902, p. 68]. (For stratigraphic position and association, see p. 145.) Upper Cambrian: Drift bowlder of Obolus sandstone at Mariehamn, Aland Island, Finland, Russia. Obolus apollinis. Orthis sp. 311x [U. S. National Museum]. (For stratigraphic position and association, see p. 146.) Middle Cambrian: Com- pact, fine-grained, quartzitic sandstone at Saltvik, Aland Island, Finland, Russia (Schmalensee, 1901). *Obolu3 (Westonia) finlandensis. Elipsocephalus (Liostracus) muticus Angelin. 311y [Wiman, 1902, p. 57]. (For stratigraphic position and association, see p. 146.) Middle? Cambrian: Drift bowlder of rusty sandstone at Ytternas, Slemmern, Aland Island, Finland, Russia. *Obolus (Westonia) alandensis. I Bradorona nitida. Lingula or Liagulella. | TrUobite (not Olenellus). 312 [U. S. National Museum]. (For stratigraphic position and association, see p. 138.) Lower Cambrian: Sand- stones of 3d of the Waucoba Springs section [Walcott, 1908f, p. 187], east of Saline Valley road, east of Waucoba Springs, Inyo County, Cal. Trematobolua excelsis. Cruziana. Holmia rowei. 312a [U. S. National Museum]. (For stratigraphic position and association, see p. 138.) Lower Cambrian: Sand- stones of 3b of the Waucoba Springs section [Walcott, 19081, p. 187], east of the Saline Valley road, east of Waucoba Springs, Inyo County, Cal. Obolella vermilionensis. Trematobolus excelsis. 313 [U. S. National Museum]. (For stratigraphic position and association, see p. 139.) Upper Cambrian: Lime- stone 0.75 mile (1.2 km.) east-northeast of McGill post office, White Pine County, Nev. Micromitra (Paterina) crenistria. Lingulella desiderata. Lingulella isse. Acrotreta idahoensis. 313a [U. S. National Museum]. (Compare 313d and 313f .) (For stratigraphic position and association, see p. 140.) Middle Cambrian: Limestone at Schellbourne, Schell Creek Range, White Pine County, Nev. Lingulella arguta?. 3131) [U. S. National Museum]. (For stratigraphic position and association, see p. 139.) Middle Cambrian: Lime- stone 3 miles (4.8 km.) north-northeast of Schellbourne, Schell Creek Range, White Pine Coimty, Nev. Micromitra (Paterina) crenistria. Lingulella desiderata. Acrotreta idahoensis alta. 3130 [U. S. National Museum]. (For stratigraphic position and association,- see p. 139.) Middle ? Cambrian: Limestone 12 miles (19.3 km.) west-southwest of Alpha Station, Eureka County, Nev. Lingulella acutangula. Lingulella desiderata. 246 CAJVIBRIAN BRACHIOPODA. 313d [IT. S. National Museum]. (Compare 313a and 313f .) (For stratigraphic position and association, see p. 139.) Lower Ordo^dcian: Limestone at Schellbourne, Schell Creek Range, WTiite Pine County, Nev. *Obolus rotundatus. 313e [U. S. National Museum]. (For stratigraphic position and association, see p. 139.) Middle Cambrian: Lime- stone 2 miles (3.2 km.) west of Green's ranch. White Pine County, Nev. (O. H. Hershey). Lingulella arguta. Linnarssonella girtyi. 313f [U. S. National Museum]. (Compare 313a and 313d.) (For stratigraphic position and association, see p. 139.) Upper Cambrian: Limestone at Schellbourne, Schell Creek Range, "^Tiite Pine Comity, Nev. *Lingulella arguta. l *Lingulella manticula. [These species are probably from more than one horizon. *Acrotreta pyxidicula.J ^ 313g [U. S. National Museum]. (For stratigraphic position and association, see p. 158.) Lower Cambrian: Lime- stone at the southern end of the Timpahute Range, Groome district, near the line between Nye and Lin- coln counties, Nev. *Nisusia (Jamesella) erecta. Billingsella sp. Callavia nevadensis Walcott. Olenellus fremonti Walcott. Peachella iddingsi (Walcott). 3131i [U. S. National Museum]. (For stratigraphic position and association, see p. 139.) Upper Cambrian: Sandy shale on Hamburg Ridge, Eureka district [Hague, 1892, Atlas], Eureka County, Nev. *Linnarssonella minuta. ' 313i [U. S. National Museum]. (For stratigraphic position and association, see p. 138.) Lower Cambrian: Lime- stone collected at long. 117° 20' W., lat. 38° N., in the western part of Esmeralda County, Nev. Kutorgina perugata. 313j [Hall and Whitfield, 1877, pp. 205 and 206]. (Specimens in U. S. National Museum.) (For stratigraphic position and association, see p. 139.) Upper Cambrian: Limestone in the Eureka district [Hague, 1892, Atlas], Eureka County, Nev. *Obolus discoideus. *Obolu3 msera. These species, in all probability, did not occur together; Hall and Whitfield give no further data, however, concerning their occurrence. 313k [U. S. National Museum]. (See 214a and 214b.) (For stratigraphic position and association, see p. 139.) Ordovician: Limestone in the White Pine district, White Pine (?) County, Nev. Linnarssonella minuta. 314 (references follow species). (For stratigraphic position and association, see p. 140.) Middle Cambrian: Lime- stone in Paradoxides zone, Chappie Arm, Trinity Bay, Newfoundland. *Acrotreta misera [Billings, 1872b, p. 470]. *Agraulos socialis [Billings, 1872b, p. 472]. *Solenopleura communis [Billings, 1872b, p. 474]. *Anapolenus venustus [Billings, 1872b, p. 474]. *Paradoxides tenellus [Billings, 1872b, p. 476]. *Paradoxides decorus [Billings, 1872b, p. 476]. 314a [Whiteaves, 1878, p. 226]. (For stratigraphic position and association, see p. 140.) Upper Cambrian: Shales on Kelleys Island, Conception Bay, Newfoundland. *Liiigulella billingsiana. 314b [Matthew, 1899e, p. 97]. (For stratigraphic position and association, see p. 141.) Lower Cambrian: Upper limestone of Matthew's Etcheminian at Smith Sound, Trinity Bay, Newfoundland. *Kutorgina granulata. 314c [Billings, 1865a, p. 220]. (For stratigraphic position and association, see p. 140.) Lower Ordo^dcian: Nodules of white limestone belonging to Division P of Billings's section at Cow Head, Newfoundland. Syntrophia calcifera. Bathyurus saffordi. LOCALITIES. 247 314(1 [Billings, Paleozoic fossils, vol. I]. (For stratigraphic position and association, see p. 140.) Lower Ordovi- cian: Limestone of Division P of the "Quebec group" 4 miles (6.4 km.) northeast of Portland Creek, Newfotmdland. *Obolus cyane (p. 216). *Lingulella iole (p. 215). *Acrotreta gemma (p. 217). *Orthis delicatula (p. 217). Strophomena aurora (p. 218). Camerella parva (p. 219). Camerella varians (p. 220). NUeus scrutator (p. 274). Illsenus fi-aternus (p. 276). *Harpides atlanticus (p. 281). *B[arpides concentricus (p. 282). Shumardia glacialis (p. 283). Cheirurus polydorus (p. 286). Cheirurus sol (p. 288). Amphion barrandei (p. 288). Triarthrus fischeri (p. 291). Telephus americanus (p. 291). Encrinurus mirus (p. 292). Remopleurides? schlotheimi (p. 294). Ampyx normalis (p. 295). *Ampyx rutilius (p. 296)., Ampyx semicostatus (p. 297). Agnostus fabius (p. 298). Agnostus galba (p. 297). 314e (references follow species). (For stratigi-aphic position and association, see p. 141.) Lower Cambrian: Lime- stone at Topsail Head, Conception Bay, Newfoundland. Micromitra (Paterina) bella [Billings, 1872b, p. 478]. Scenella reticulata [Billings, 1872b, p. 479]. _Agraulos strenuus [Billings, 1872b, p. 473.] "Walcott [18S6a, p. 150] adds the following species: Salterella. Micromitra (Paterina) labradorica?. Stenotheca rugosa (Hall). Protypus senectus parvulus. 314i [U. S. National Museum]. (For stratigraphic position and association, see p. 141.) Lower Cambrian: Lime- stone of B7 of the section at Bonne Bay [Walcott, 1891b, p. 255], Newfoundland. Obolella chromatica. Micromitra (Paterina) labradorica. -Mesonacis vermontana (Hall). Conocephalites. Bathyurus. Salterella. 314g [Billings, 1865b, p. 362]. (For stratigraphic position and association, see p. 140.) Lower Ordovician: A loose piece of gray argillaceous limestone at Maiden Arm, Hare Bay, on the east side of the northern point of Newfoundland. "*Obolus? murrayi. 314h [U. S. National Museum]. (For stratigraphic position and association, see p. 140.) Middle Cambrian: Shale on Manuels Brook, Conception Bay, Newfoundland. -Acrotreta misera. 314i [U. S. National Museum]. (For stratigraphic position and association, see p. 140.) Upper Cambrian: Shale picked up on beach in Smith Sound, Trinity Bay, Newfoundland (C. D. Walcott, 1899). Omsia lenticularis. 315 (references follow species). Middle ? Cambrian: Limestone at Curramulka, Yorke Peninsula, South Australia. *Micromitra (Paterina) etheridgei [Tate, 1892, p. 184]. Kutorgina peculiaris [Tate, 1892, p. 185]. *Nisusia compta [Tate, 1892, p. 185]. 315a [Tate, 1892, p. Australia. *Kutorgina peculiaris. 185]. Middle? Cambrian: Limestone at Parara, near Ardrossan, Yorke Peninsula, South 315b [Etheridge, 1905a, p. 249]. Middle? Cambrian: Limestone atWirrialpa, Flinders Range, South Australia. -*Eoorthis tatei. 315c [Etheridge, 1905, p. 250]. Middle? Cambrian: "Archseocyathinse white limestone" at Wirrialpa, Flinders Range, South Australia. ■-*Huenella etheridgei. Lower? Cambrian: Limestone near Wirrialpa, 315d [Etheridge, 1905, p. 248, and U. S. National Museum]. Flinders Range, South Australia. *Obolella wirrialpensis. 316 [Davidson, 1871, p. 343]. (For stratigraphic position and association, see p. 135.) Lower Ordovician: Upper Llandeilo (?) black shales at Dobbs Linn, near Moffat, in Dumfriesshire, Scotland. '-* Acrotreta nicholsoni. 248 CAIMBRIAN BRACHIOPODA. 316a [Da^-idson, 1883, p. 213]. (For stratigraphic position and association, Beep. 135.) Lower Ordovician: Llandeilo at Craighead, Ardmillan Brae, and Balcletchie, all three in the Girvan district of Ayrshire, Scotland. Acrotreta nicholsoni. 316b [Davidson, 1883, p. 211]. (For stratigraphic position and association, see p. 136.) Middle Cambrian: At Cairn Burn and Druidhill Burn, botJi in Dumfriesshire, Scotland. Acrotreta sagittalis. 316c [Geol. Survey Scotland, M4197d; personal communication, J. Home, 1910]. (For stratigraphic position and association, see p. 136.) Lower Cambrian: Probably equivalent to those in band 6 or 7 of the section on the north slope of Meall & Ghiubhais [P.each and Home, 1907, p. 414], on the Bruachaig River, 2 miles (3.2 km.) east-northeast of the Kinlochewe Hotel, Loch Maree, Ross-shire, Scotland. *Lingulella zeus. Olenellus lapworthi? Peach and Home. 316d [Geol. Survey Scotland, M2646e, M2647e, and M4178d; personal communication, J. Home, 1910]. (For stratigraphic position and association, see p. 136.) Lower Cambrian: About 500 feet (152.5 m.) above the provisional base of the Cambrian and 75 feet (23 m.) below what is believed to be the top of the Lower Cambrian, in the shales forming 5 and 6 of the section given by Peach and Home [1907, p. 414], in a small burn on the north slope of Meall a Ghiubhais, 4 miles (6.4 km.) west-northwest of the Kinlochewe Hotel, Loch Maree, Ross-shire, Scotland. *Micromitra scotica. Olenellus lapworthi? Peach and Home. 317 [Davidson, 1883, p. 213]. Lower Ordovician: Coalpit Bay, County Down, Ireland. Acrotreta nicholsoni. 317a [Davidson, 1871, p. 340]. Middle Cambrian: At Bellewstown, County Meath, and at Balbriggan, County Dublin, both in Ireland. Acrotreta sagittalis?. 317b [Davidson, 1866, p. 58]. Middle Cambrian: Shales at Bellewstown, County Meath, Ireland. Lingulella davisi. 318 [Davidson, 1869, p. 232]. (For stratigraphic position and association, see p. 135.) Upper Cambrian: Upper Lingula flags at Penmain Pool, west of Dolgelly, Merionethshire, North Wales. Orusia lenticularis. 318a [Davidson, 1868, p. 314]. (For stratigraphic position and association, see p. 135.) Upper Cambrian: Upper Lingula flags at Criccieth, Carnarvonshire, North Wales. Orusia lenticularis. 318b [Davidson, 1869, p. 232]. (For stratigraphic position and association, see p. 135.) Upper Cambrian: Upper Lingula flags near Portmadoc, Carnarvonshire, North Wales. Orusia lenticularis. 318c [Davidson, 1868, p. 310]. (For stratigraphic position and association, see p. 135.) Upper Cambrian: Lower Lingula flags at the Rheider Waterfall Valley and at Gwynfynydd and other places near Dolgelly, North Wales. Acrotreta sagittalis. 318d (references follow species). (For stratigraphic position and association, see p. 136.) Middle Cambrian: Sandstones in the middle portion of the Menevian at Porth-y-rhaw, St. Davids, South Wales. Acrothele maculata [Davidson, 1871, p. 341]. *Orbiculoidea pileolus [Davidson, 1868, p. 316]. *Billingsella hicksi [Davidson, 1869, p. 230]. 318e (references follow species). (For stratigraphic position and association, see p. 136.) Middle Cambrian: Lower portion of the Menevian at Camlan, North Wales. Lingulella ferruginea [Davidson, 1871, p. 337]. Acrothele maculata [Davidson, 1871, p. 341]. Orbiculoidea pileolus [Davidson, 1871, p. 345]. 318f [Davidson, 1871, p. 341]. (For stratigraphic position and association, seep. 136.) Middle Cambrian: Lower portion of the Menevian at Gwynfynydd, North Wales. Acrothele maculata. 318g [Davidson, 1868, p. 310]. (For stratigraphic position and association, see p. 135.) Upper Cambrian: Lower Lingula flags at Porth-y-rhaw, Pen-y-pleidiau, and several other localities near St. Davids, South Wales. *Acrotreta sagittalis. LOCALITIES. . 249 31811 [U. S. National Museum]. (For stratigraphic position and association, see p. 136.) Middle Cambrian: Shales in the Menevian at St. Davids, South Wales. Lingulella feiTuginea. I Acrotreta sagittalis. Acrothele maculata. I Billingsella hicksi. 3181 [U. S. National Museum]. (See 366c.) (For stratigraphic position and association, seep. 136.) Middle? Cambrian: Red shales of the Caerfai group at St. Davids, South Wales. Lingulella primseva. 318] [Salter, 1866b, p. 340]. (For stratigraphic position and association, see p. 136.) Middle Cambrian: Black shales of the Menevian group at Pen-y-pleidiau, St. Davids, South Wales. *Lingulella ferruginea. 318k [Davidson, 1871, p. 337]. (For stratigraphic position and association, see p. 136.) Middle Cambrian: In the Menevian rocks at Tafern Helig, North Wales. Lingulella ferruginea. 318 1 [Davidson, 1871, p. 337]. (For stratigraphic position and association, see p. 136.) Middle Cambrian: In the Menevian rocks at the Waterfall Valley, near llaentwrog, North Wales. Lingulella ferruginea. 318m [Davidson, 1866, p. 57]. (For stratigraphic position and association, see p. 135.) Upper Cambrian: Near the base of the lower, black slatea at the Waterfall Valley, near Maentwrog, North Wales. Lingulella davisi. 31811 [Davidson, 1871, p. 337]. (For stratigraphic position and association, see p. 136.) Middle Cambrian: Red shales at the base of the Harlech grits at St. Davids, South Wales. Lingulella ferruginea. 3180 [Davidson, 1871, p. 337]. (For stratigraphic position and association, see p. 136.) Middle Cambrian: Red shales at the base of the Harlech grits at Solva, St. Davids, South Wales. Lingulella ferruginea. 318p (references follow species). (For stratigraphic position and association^ see p. 136.) Middle Cambrian: Sand- stones in the middle portion of the Menevian at Ninewells, near St. Davids, South Wales. Orbiculoidea pileolus [Davidson, 1871, p. 344]. *Billingsella hicksi [U. S. National Museum and Davidson, 1869, p. 230]. 318q [Davidson, 1871, pp. 344-345]. (For stratigraphic position and association, see p. 136.) Middle Cambrian: Yellowish-gray beds in the Harlech group, on the road between Solva and Whitechurch, St. Davids, South Wales. Orbiculoidea pileolus?. 318r [Davidson, 1871, p. 344]. (For stratigraphic position and association, see p. 136.) Middle Cambrian: Sand- stones in the middle portion of the Menevian at Solva Harbor, St. Davids, South Wales. Orbiculoidea pileolus. 318s [Davidson, 1868, p. 314]. (For stratigraphic position and association, see p. 135.) Upper Cambrian: Upper Lingula flags at Ogof-ddu Cliff, Carnarvonshire, North Wales. Orusia lenticularis. 318t [Davidson, 1868, p. 314]. (For stratigraphic position and association, see p. 135.) Upper Cambrian: Upper Lingula flags at Penmorfa Church, Tremadoc, Carnarvonshire, North Wales. Orusia lenticularis. 318u (references follow species). (For stratigraphic position and association, see p. 135.) Upper Cambrian Upper Lingula flags at Gwerny-y-Barcud, North Wales. Lingulella ferruginea [Davidson, 1868, p. 315]. Orusia lenticularis [Davidson, 1868, p. 314]. 318v (references follow species). (For stratigraphic position and association, see p. 135.) Upper Cambrian: Upper Lingula flags at Rhiwfelyn, North Wales. Lingulella ferruginea [Davidson, 1868, p. 315]. Orusia lenticularis [Davidson, 1869, p. 232]. 318w [U. S. National Museum]. (For stratigraphic position and association, see p. 135.) Upper Cambrian: Trema- doc shale on Ramsey Island, St. Davids, South Wales. Eoorthis carausii. 250 CAIIBRIAN BRACHIOPODA. 319 [Geol. Survey Canada]. (See 319i; may be same locality.) Lower Ordovician: Limestone No. 1 of Billings's Point Levis section, Point Levis, Province of Quebec, Canada. *Elkania ida. *Acrotreta ovalis. The following species are quoted from this locality by Billings, Paleozoic Fossils, vol. 1: Metoptoma venillia (p. 88). *Orthis ? apicalis (p. 301). *Agnostus canadensis (p. 397). *Agnostus orion (p. 397). *Conocephalites zenkeri (p. 398). *Arionellus cylindricus (p. 406). *Arionellus subclavatus (p. 406). *Menocephalus globosus (p. 408). *Menocephalus sedgmcki (p. 407). *Dikellocephalus belli (p. 403). *Dikellocephalus cristatus (p. 404). *Dikellocephalus hisingeri (p. 196). *Dikellocephalus magnificus (p. 399). *Dikellocephalus megalops (p. 403). *Dikellocephalus oweni (p. 402). *Dikellocephalus pauper (p. 200). *Dikellocephalus planifrons (p. 401). *Dikellocephalus selectus (p. 199). *Dikellocephalus sesostris (p. 198). *Bathyurus armatus (p. 411). *Bathyurus capax (p. 409). *Bathyurus dubius (p. 410). 319a (references follow species). Lower Ordovician: Levis shales, Point Levis, Pro^^nce of Quebec,, Canada. *LingulelIa irene [Billings, 1862b, p. 72]. *Elkania desiderata [U. S. National Museum and Billings, 1862b, p. 70]. *Acrothele levisensis (Geol. Survey Canada). Lingulella sp. undt. (U. S. National Museum). 319b [U. S. National Museum]. Lower Cambrian: Conglomeratic limestones containing Olenellus?, St. Simon, Rimouski (?) County, Province of Quebec, Canada. Bicia gemma. Obolella crassa. *Obolella crassa elongata. *AcrotheIe sp. undt. a. Billingsella salemensis occurs at the same locality as the specimens mentioned above, but its stratigraphic posi- tion is not known. Hyolithes americanus Billings. Olenellus?. Agraulos redpathi Walcott. 319c [Billings, lS62b, p. 69]. Ordovician: Shales at Cape Rouge, above Quebec, Province of Quebec, Canada. Acrothele pretiosa. 319d [Billings, 1865a, p. 301]. Upper Cambrian: Limestone bowlder in Lower Ordovician conglomerate. Point Levis, Quebec, Canada. *Lingulella iris. 319e (references follow species). Lower Cambrian: Sandy shales about 2 miles (3.2 km.) east of Swanton, Franklin County, Vt. (See Locality 25a; the only known locality is nearly 2 miles east of Swanton, and Locality 319e has therefore been entered as 2 miles, though Billings gives it as 1.5 miles.) Kutorgina cingulata [Billings, 1861b, p. 9]. *Nisusia festinata [Billings, 1861b, p. 10]. *Swantonia antiquata [U. S. National Museum and Billings, lS61b, p. 11]. 319f [U. S. National Museum], Lower Ordovician: Drift bowlder of sandstone found near St. Albans, Franklin County, Vt. The lithologic characters of the matrix in which this species was found point to the arenaceous limestones of the Phillipsburg formation just north of the boundary between the United States and Canada as the source of the bowlder. *Billingsella dice. 319g [Whitfield, 1884, p. 144]. Lower Cambrian: Shales at Parker's quarry, near Georgia, Franklin County, Vt. *Billingsella orientalis. Olenellus thompsoni. 3191i [U. S. National Mus^m]. Lower Cambrian: Limestone bowlders in conglomerate at Metis, on the St. Law- rence, below Quebec, Canada. Billingsella salemensis. I Olenellus? sp. Hyolithellus micans (Billings). | Ptychoparia metisensis Walcott. 3191 [Billings, 1862b, p. 71, and Geol. Survey Canada]. (See 319; may be same locality.) Lower Ordovician: Limestone at Point Levis, Province of Quebec, Canada. Elkania ida. LOCALITIES. 251 319] [U. S. National Museum]. (See 319k.) Lower Cambrian: Sandstone 50 feet (15 m.) above the base of the sec- tion west of Parker's quarry and about a mile (1.6 km.) from the shore of Lake Champlain, in the town- ship of Georgia, Franklin County, Vt. Hyolithes sp. Olenellus? sp. Ptychoparia trilineata (Emmons). 3otsfordia cselata. Byolithellus micans (Billings). HyoUthes americanus Billings. Hyolithes communis Billings. 319k [U. S. National Museum records]. (See 319j.) Lower Cambrian: Calcareous sandstone near the base of the section west of Parker's quarry, on cliff overlooking Lake Champlain, near Georgia, Franklin County, Vt. Obolella crassa. 319 1 [Billings, 1872a, p. 220, and IT. S. National Museum.] Lower Cambrian: Limestone bowlders in conglomerate at Trois Pistoles, Temiscouata County, on St. Lawrence River, below Quebec, Canada. *Quebecia circe. 319m [Walcott, 189ib, p. 278]. Lower Cambrian: Shales of No. 6 of the section at Parker's quarry, near Georgia, Franklin County, Vt. Kutorgina cingulata. Billingsella orientalis. Nisusia festinata. Nisusia festinata transversa. *Pal8eophycus congregatus Billings. *PalKophycus incipiens Billings^. Phyllograptus (?) cambrensis Walcott. *Climacograptus (?) emmonsi Walcott. *Microdiscus parkeri. *Mesonacis vermontana (Hall). *01enellus thompsoni (Hall). *01enoides marcoui CWhitfield). *Bathynotus holopyga (Hall). Ptychoparia adamsi (Billings). Ptychoparia vulcanus (Biflings). *Protypus hitchcocki C^Tiitfield) . Protypus senectus (BilUngs). Protypus senectus parvulus (Billings). 319n [Billings, 1859, p. 432]. Ordovician: "Chazy formation" on the island of Montreal, in St. Lawrence River, Canada. *Obolu3 belli. 319o [Billings, 1859, p. 432]. Ordovician: "Chazy formation" near L'Original, on St. Lawrence River, Canada. Obolus belli. 319p [Billings, 1859, p. 432]. Ordovician: "Chazy formation" on Allumette Island, in St. Lawrence River, Canada. Obolus belli. 319c[ [U. S. National Museum records]. Upper Cambrian: Limestone 1 mile (1.6 km.) south-southwest of High- gate Falls, Franklin County, Vt. Obolus msera?. 319r [U. S. National Museum]. (See 319e and 25a.) Lower Cambrian: On the Bullard farm, about 2 miles (3.2 km.) east of Swanton, Franklin County, Vt. Rusfella edsoni. Olenellus thompsoni (Hall). 319s [U. S. National Museum]. Middle Cambrian: "St. Albans formation" at St. Albans, Franklin County, Vt. Obolus matinalis?. '*Huenella vermontana. Paradoxides sp. 319t [Billings, 1865a, p. 220]. Lower Ordovician: "Calciferous sandrock" at St. Timothy, on the St. Lawrence, near the head of the Beauharnois Canal, Province of Quebec, Canada. Syntrophia calcifera. 319u [Billings, 1861a, p. 320]. Lower Ordovician: "Calciferous sandrock" in the township of Edwardstown, between Beauharnois and Lake Champlain, Province of Quebec, Canada. Syntrophia calcifera. 319v [U. S. National Museum]. (See 319y.) Lower Cambrian: Sandy shale 2 miles (3.2 km.) east of Highgate Springs, Franklin County, Vt. (CD. Walcott, 1889). Lingulella franklinensis. 319w [IT. S. National Museum]. (See 319x.) Lower Cambrian: Limestone 1.25 miles (2 km.) north of Rutland, Rutland County, Vt. (T. N. Dale). JSfisusia festinata. 252 CAJVIBRIAN BRACHIOPODA. 319x [U. S. National Museum]. (See 319w.) Lower Cambrian: Limestone at the crossing of East Creek and Grove Street, 1.25 miles (2 km.) north of Rutland, Rutland County, Vt. (A. F. Foerste, 1890). Micromitra (Paterina) labradorica swantonensis. 319y [U. S. National Museum]. (See 26 and 319v.) Lower Cambrian: Sandstone 2 miles (3.2 km.) east-southeast of Highgate Springs, Franklin County, Vt. (C. D. Walcott, 1889). Micromitra (Paterina) labradorica swantonensis. Stenotheca rugosa (Hall). Ptychoparia sp. 319z [U. S. National Museum]. (See 25a.) Lower Cambrian: Sandy limestone 2.5 miles (4 km.) east of Swanton,, Franklin County, Vt. (C. D. Walcott, 1897). Micromitra (Paterina) labradorica swantonensis. 320 [Wallerius, 1895, p. 66]. (For stratigraphic position and association, see p. 145.) Middle Cambrian: Gudhem, 12.5 miles (20.1 km.) south-southeast of Skara, Pro^dnce of Skaraborg, Sweden. Acrotreta parvula. 320a [Wallerius, 1895, p. 66]. (For stratigraphic position and association, see p. 145.) Middle Cambriani Djupadal, 19 miles (30.6 km.) south-southeast of Skara, Province of Skaraborg, Sweden. *Acrotreta parvula. Agnostus Ifevigatus Dalman. . 320b [IT. S. National Museum]. (For stratigraphic position and association, see p. 145.) Middle Cambrian: Lime- stones forming 2d of the Paradorides zone, the Agnostus Ixvigatus horizon, at Gudhem, 12.5 miles (20.1 km.) south-southeast of Skara, Province of Skaraborg, Sweden. Acrothele coriacea. I *Billingsella exporrecta. Acrothele (Redlichella) granulata. | *Billingsella exporrecta rugosicostata. 320c [Wallerius, 1895, p. 66]. (For stratigraphic position and association, see p. 145.) Middle Cambrian: Andrarum limestone at Andrarum, 20 miles (32 km.) northwest of Simrishamn, Province of Christianstad, Sweden. Acrotreta schmalenseei. 320d [U. S. National Museum]. (For stratigraphic position and association, seep. 146.) Middle Cambrian: Exsu- lans limestone in the lower part of the Paradoxides tessini zone at Fogels&ng, 5 miles (8 km.) east of Lund^ Province of Malmohus, Sweden. • Acrotreta schmalenseei. 320e pj. S. National Museum]. (See 321q.) (For stratigraphic position and association, see p. 145.) Middle Cambrian: Limestone at Munkesten, north of Hunneberg, Province of Skaraborg, Sweden. Acrotreta schmalenseei. 320f [U. S. National Museum]. (See8w, 3101, and 321y.) (For stratigraphic position and association, see p. 145.) Middle Cambrian: Limestone at Andrarum, 20 miles (32 km.) northwest of Simrishamn, Province of Chris- tianstad, Sweden. Micromitra pusilla. Micromitra (Iphidella) ornatelL Acrothele coriacea. Orusia lenticularis. 320g [U. S. National Museum]. (For stratigraphic position and association, see p. 145.) Middle Cambrian: Lime- stones of the Paradoxides forchhammeri zone at Borgholm, Oeland Island, Sweden. Acrothele coriacea. Billingsella exporrecta. 32011 [Gronwall, 1902, p. 39]. (For stratigraphic position and association, see p. 145.) Middle Cambrian: Shales in the Paradoxides tessini zone at Lovened, 19 miles (80.6 km.) south-southeast of Skara, Province of Skara- borg, Sweden. Acrothele intermedia. 320i [Gronwall, 1902, p. 39]. (For stratigraphic position and association, see p. 145.) Middle Cambrian: Limestones of the Coronatus zone at Andrarum, 20 miles (32 km.) northwest of Simrishamn, Province of Christianstad, Sweden. Acrothele intermedia. 320j [Gronwall, 1902, p. 39]. (For stratigraphic position and association, see p. 145.) Middle Cambrian: Lime- stones of the Coronatus zone at Gislof , Province of Malmohus, Sweden. Acrothele intermedia. LOCALITIES. 253 320k (references follow species). (For stratigraphic position and association, see p. 145.) Middle Cambrian: Lime- stones at Kiviks Esperod, Province of Malmohus, Sweden. Acrothele coriacea (U. S. National Museum). *Acrotliele intermedia [Gronwall, 1902, p. 39]. The exact horizon from which the specimens of Acrothele coriacea were obtained is not known. Acrothele inter- Tnedia was obtained from the Coronatus zone. 3201 (references follow species). (For stratigraphic position and association, see p. 146.) Middle Cambrian: Drift blocks supposed to have come from the Paradoxides mlandicus zone [Linnarsson, 1876, p. 6], at Lillviken, near Oestersund, Province of Jemtland, Sweden. *Obolus sp. undt. g [Linnarsson, 1876, p. 16]. Acrothele coriacea [Linnarsson, 1876, p. 23]. *Acrothele (Redlichella) granulata [Linnarsson, p. 24]. (Referred to as "A. coriacea.") 1876, Billingsella exporrecta [Linnarsson, 1876, p. 13]. Billingsella lindstromi [Linnarsson, 1876, p. 12]. 320m (references follow species). (For stratigraphic position and association, see p. 145.) Middle Cambrian: Limestones of the Paradoxides forchhammeri zone at Kinnekulle, northeast of Lidkoping, Province of Skara- borg, Sweden. Billingsella exporrecta [Linnarsson, 1876, p. 13]. Orthis aff. hicksi [Linnarsson, 1876, p. 14]=Billingsella exporrecta rugosicostata. *Billingsella lindstromi [U. S. National Museum and Lin- narsson, 1876, pp. 11, 12, and 33]. Lingula or Lingulella [Linnarsson, 1876, p. 15]=Lingulella ferruginea. *Acrothele coriacea [Linnarsson, 1876, p. 23]. Acrotreta socialis [Linnarsson, 1876, p. 18]=Acrotreta schmalenseei. 320n (references follow species). (For stratigraphic position and association, see p. 145.) Middle Cambrian: Lime- stones of the Paradoondes forchhammeri zone at Lovened, Djupadal, 19 miles (30.6 km.) south-southeast of Skara, Province of Skaraborg, Sweden. '*Micromitra (Iphidella) ornatella [U. S. National Museum and Linnarsson, 1876, p. 26]. Lingula or Lingulella [Linnarsson, 1876, p. 16]=Lingu- lella ferruginea. *Lingulella linnarssoni (U. S. National Museum). Acrothele coriacea [U. S. National Museum and Linnars- son, 1876, p. 23]. -Acrotreta schmalenseei (U. S. National Museum). Acrotreta socialis (U. ,S. National Museum). *Billingsella exporrecta [U. S. National Museum and Lin- narsson, 1876, pp. 13 and 33]. Billingsella exporrecta rugosicostata (U. S. National Museum). Orthis aff. hicksi [Linnarsson, 1876, p. 14]= Billingsella exporrecta rugosicostata. Billingsella lindstromi (U. S. National Museum). 3200 [Linnarsson, 1876, p. 23]. (For stratigraphic position and association, seep. 146.) Middle Cambrian: Lime- stone band between the Holmia kjerulfi zone and the Paradoxides tessini zone at Andrarum, 20 miles (32 km.) northwest of Simrishamn, Province of Christianstad, Sweden. Acrothele coriacea. 320p (references follow species). (For stratigraphic position and association, see p. 145.) Middle Cambrian: Lime- stones of the Paradoxides forchhammeri zone at Sodra Mockleby, southern part of Oeland Island, Sweden, Acrothele coriacea [Linnarsson, 1876, p. 23]. Billingsella exporrecta [Linnarsson, 1876, p. 13]. Orthis aff. hicksi [Linnarsson, 1876. p. 14] =Billingsella exporrecta rugosicostata. Billingsella lindstromi [Linnarsson, 1876, p. 12]. 320q [U. S. National Museum]. (See 309j.) (For stratigraphic position and association, see p. 145.) Middle Cam- brian: Limestone forming 2c of the Paradoxides forchhammeri zone at Alunbruk (alum works), southern part of Oeland Island, Sweden (Schmalensee, 1899). Agnostus. Dolichometopus svecicus Angelin Acrothele coriacea. Acrothele intermedia. Billingsella lindstromi. 320r [U. S. National Museum]. (I^or stratigraphic position and association, see p. 145.) Middle Cambrian: Lime- stones of the Agnostus Ixvigatus zone at Himneberg, western boundary of the Province of Skaraborg, Sweden. Acrothele coriacea. 320s [Linnarsson, 1877, p. 374]. (For stratigraphic position and association, see p. 146.) Middle Cambrian: At St. Fro, Oeland Island, Sweden. Acrothele (Redlichella) granulata. 320t [Linnarsson, 1876, p. 24]. (For stratigraphic position and association, see p. 146.) river Billstaan, parish of Hackas, Province of Jemtland, Sweden. Acrothele (Redlichella) granulata. Middle Cambrian: On the 254 CAMBRIAN BRACHIOPODA. 320u [Linnarsson, 1S76, p. 25]. (For stratigraphic position and association, see p. 145.) Middle Cambrian: Strata, with Agnostus Icevigatus at Ostra Rynninge, in Nerike, Sweden. Micromitra pusilla. 320v [Linnarsson, 1876, p. 23]. (See 320z.) (For stratigraphic position and association, see p. 145.) Middle Cam- brian: In the Paradoxides forchhammeri zone at Lanna, Hjulsta, Vinala, and Vrana, all four in Nerike, Sweden. Acrothele coriacea. 320w [Holm, 1898, p. 148]. (For stratigraphic position and association, see p. 144.) Passage beds between the Upper Cambrian and the Ordovician : Ceratopyge limestone at Glote, in Herje&dalen, Province ot Jemtland, Sweden. Lingulella lepis. 320x [Linnarsson, 1876, p. 16; U. S. National Museum]. (For stratigraphic position and association, see p. 146.) Lower Cambrian: In strata with Holmia kjerulfi. at Andrarum, 20 miles (32 km.) northwest of Simrishamn, Province of Christianstad, Sweden. *Lingulella nathorsti. Holmia kjerulfi (Brogger). 320y (references follow species). (For stratigraphic position and association, see p. 145.) Middle Cambrian: Lime- stones of the Paradoxides forchhammeri zone at Gudhem, 12.5 miles (20.1 km.) south-southeast of Skara, Province of Skaraborg, Sweden. Micromitra (Iphidella) ornatella (U. S. National Museum). I Billingsella exporrecta [Linnarsson, 1876, p. 13]. Acrothele coriacea (U. S. National Museum). | Billingsella lindstromi (U. S. National Museum). 320z [Linnarsson, 1876, p. 13]. (See 320v.) (For stratigraphic position and association, see p. 145.) Middle Cam- brian: Limestones of the Paradoxides forchhammeri zone at several places in Nerike, Sweden. Billingsella exporrecta. 321 [Wlman, 1902, p. 68]. (For stratigraphic position and association, see p. 145.) Upper Cambrian: Drift bowlders of Obolus sandstone, Nos. 1, 2, 4-6, 10-16, 18-20, 22-23, 25-29, on Fanton Island, parish of Borstil, Province of Stockholm, Sweden. Obolus apollinis. 321a [Wiman, 1902, p. 68]. (For stratigraphic position and association, see p. 145.) Upper Cambrian: Drift bowl- ders of Obolus sandstone, Nos. 3 and 7, on Fanton Island, parish of Borstil, Province of Stockholm, Sweden. Obolus apollinis. Problematicum. 321b [T\^iman, 1902, p. 68]. (For stratigraphic position and association, see p. 145.) Upper Cambrian: Drift bowlder of Obolus sandstone. No. 8, on Fanton Island, parish of Borstil, Province of Stockholm, Sweden. Obolus apollinis. Hyolithes. 321c [Wiman, 1902, p. 68]. (For stratigraphic position and association, see p. 145.) Upper Cambrian : Drift bowlder of Obolus sandstone. No. 17, on Fanton Island, parish of Borstil, Province of Stockholm, Sweden. Obolus apollinis. Oljolus (Schmidtia) obtusus?. 321d [Wiman, 1902, p. 68]. (For stratigraphic position and association, see p. 145.) Upper Cambrian: Drift bowlder of Obolus sandstone. No. 21, on Fanton Island, parish of Borstil, Province of Stockholm, Sweden. Obolus apollinis. Obolus (Schmidtia) celatus orbiculatus. 321e [Wiman, 1902, p. 68]. CFor stratigraphic position and association, see p. 145.) Upper Cambrian: Drift bowlde'r of Ceratopyge slate, No. 1, on Biludden, about 20 miles (32.2 km.) east of Gefle, Province of Gefleborg, Sweden. Acrotreta cf. sagittalis. Shumardia oelandica Moberg?. Conodont. 321f [Wiman, 1902, p. 68]. (For stratigraphic position and association, see p. 145.) Upper Cambrian: Drift bowlder ot Ceratopyge slate. No. 2, on Biludden, about 20 miles (32.2 km.) east of Gefle, Province of Gefleborg, Sweden. Acrotreta cf. sagittalis. Trilobite?. LOCALITIES. 255 321g [Wiman, 1902, p. 68j. (For stratigraphic position and association, see p. 145.) Upper Cambrian: Drift bowlder of Ceratopyge slate, No. 3, on BUudden, about 20 miles (32.2 km.) east of Gefle, ProAdnce of Gefleborg, Sweden. Acrotreta cf. sagittalis. I Trilobite?. Shumardia celandica Moberg?. | Conodont. 321h [Wiman, 1902, p. 68]. (For stratigraphic position and association, see p. 145.) Upper Cambrian: Drift bowlders of Ceratopyge slate, Nos. 4, 6, and 7, on Biludden, about 20 miles (32.2 km.) east of Gefle, Province- of Gefleborg, Sweden. Acrotreta cf . sagittalis. Conodont. 321i |T\''iraan, 1902, p. 68]. (For stratigraphic position and association, see p. 145.) Middle Cambrian: Drift bowlders of Ceratopyge slate, Nos. 8 and 23, on Biludden, about 20 miles (32.2 km.) east of Gefle, Province of Gefleborg, Sweden. Acrotreta cf . sagittalis. Discina? sp. 321] [Wiman, 1902, p. 68]. (For stratigraphic position and association, see p. 145.) Upper Cambrian: Drift bowlder of Ceratopyge slate. No. 9, on Biludden, about 20 miles (82.2 km.) east of Gefle, Province of" Gefleborg, Sweden. Acrotreta cf. sagittalis. I Trilobite?. Shumardia celandica Moberg?. | Conodont. 321k [Wiman, 1902, p. 68]. (For stratigraphic position and association, see p. 145.) Upper Cambrian: Drift bowlder of Ceratopyge slate, No. 12, on Biludden, about 20 miles (32.2 km.) east of Gefle, Province of Gefleborg, Sweden. Acrotreta cf. sagittalis. Trilobite?. Conodont. 3211 [Wiman, 1902, p. 68]. (For stratigraphic position and association, see p. 145.) Upper Cambrian: Drift bowlder of Ceratopyge slate. No. 14, on Biludden, about 20 miles (32.2 km.) east of Gefle, Province of Gefleborg, Sweden. Lingulella lepis?. Acrotreta cf . sagittalis. Graptolite. 321m [W^iman, 1902, p. 68]. (For stratigraphic position and association, see p. 145.') Upper Cambrian: Drift bowlders of Ceratopyge slate, Nos. 17 and 27, on Biludden, about 20 miles (32.2 km.) east of Gefle, Province of Gefleborg, Sweden. Lingulella lepis?. Acrotreta cf. sagittalis. Discina sp. Shumardia celandica Moberg. 321n [Wiman, 1902, p. 68]. (For stratigraphic position and association, see p. 145.) Upper Cambrian: Drift bowlder of limestone {Ceratopyge slate horizon) at Trodje, in Gastrikland, Sweden. Graptolite. Ceratopyge forficula Sars. Shumardia bottnica Wiman. Obolella sp. Acrotreta cf . sagittalis. Acrotreta sp. Orthis sp. 3210 [Wiman, 1902, p. 68]. (For stratigraphic position and association, see p. 145.) Upper Cambrian: Drift- bowlder cf Obolus sandstone. No. 9, on Fanton Island, parish of Borstil, Province of Stockholm, Sweden. Obolus apollinis. Lingulella sp. 321p [Wallerius, 1895, p. 67]. (For stratigraphic position and association, see p. 145.) Middle Cambrian: In strata with Agnoslus Ixvigatus at Carlfors, near the north end of Mount Billingen, Province of Wermland, Sweden. Billingsella expon-ecta. 321q [U. S. National Museum]. (See 320e.) (For stratigraphic position and association, see p. 145.) Middle Cam- brian: Limestones of the Paradoxides forckbammeri zone at Munkesten, north of Hunneberg, western boundary of the Province of Skaraborg, Sweden (Schmalensee, 1899). Acrothele coriacea. Acrotreta schmalenseei. Billingsella expon-ecta. 256 CAMBRIAN BRACHIOPODA. 3211." (For stratigraphic position and association, see p. 145.) Middle Cambrian: Limestones of the Paradoxides forchhammeri zone at Hunneberg, western boundary of the Province of Skaraborg, Sweden. Billingsella exporrecta. 321s [U. S. National Museum]. (For stratigraphic position and association, see p. 146.) Lower Cambrian: Brown sandstone interbedded in gray sandatone at Sularp, near Lund, Province of Malmohus, Sweden. Obolella lindstromi. *Obolella mobergi. 321t [U. S. National Museum]. (For stratigraphic position and association, see p. 145.) Middle Cambrian; Sand- stone at Sularp, near Lund, Province of Malmohus, Sweden. Billingsella lindstromi. 321u [U. S. National Museum]. (For stratigraphic position and association, see p. 145.) Middle Cambrian: Sand- stone at Bjorkelunda, south of Simrishamn, Province of Christianstad, Sweden. Billingsella lindstromi. 321v [U. S. National Museum]. (For stratigraphic position and association, see p. 146.) Lower Cambrian: Gray sandstone of the Mesonads torelli zone at Bjorkelunda, south of Simrishamn, Province of Christianstad, Sweden. *Obolella lindstromi. Obolella mobergi. Mesonacis torelli Moberg. 321x [U. S. National Museum]. (For stratigraphic position and association, see p. 145.) Upper Cambrian: Dictyo- graptus slate at Alunbruk (alum works), southern part of Oeland Island, Sweden (Schmalensee, 1899). Obolus (Broggeria) salteri. 321y [U. S. National Museum]. (See 8w, 310 1, and 320f .) (For stratigraphic position and association, see p. 145.) Middle Cambrian: Shale at Andrarum, 20 miles (32 km.) northwest of Simrishamn, Province of Christianstad, Sweden. Acrotreta sagittalis. 321z [U. S. National Museum], (For stratigraphic position and association, see p. 145.) Middle Cambrian: Shales at Fogelstog, 5 miles (8 km.) east of Lund, Province of Malmohus, Sweden. Acrotreta sagittalis. 322 [U. S. National Museum]. (For stratigraphic position and association, see p. 152.) Middle Cambrian: Lime- stone (stratigraphic position unknown) about 6 miles (9.6 km.) west-southwest of Liberty and 15 miles (24.2/ km.) west of Montpelier, Bear Lake County, Idaho. Acrotreta pyxidicula. 322a [U. S. National Museum]. (For stratigraphic position and association, see p. 152.) Middle Cambrian: Lang- ston limestone near Paris, Bear Lake County, Idaho (R. S. Spence). *Acrotreta idahoensis sulcata. Microdiscus. Ptychoparia, 2 sp. 323 [Wiman, 1902, p. 66]. (For stratigraphic position and association, see p. 144.) Passage beds between the Upper Cambrian and the Ordovician: Phyllograptus s\a.te and Ceratopyge limestone in the Christiania region, Norway. Acrotreta sagittalis. 323a fWiman, 1902, p. 66]. (For stratigraphic position and association, seep. 145.) Upper Cambrian: Ceratopyge slate in the Christiania region, Norway. Acrotreta sagittalis. Lingulella lepis. 3231) [U. S. National Museum]. (For stratigraphic position and association, see p. 146.) Middle Cambrian: Lime- stone of Paradoxides alandicus zone at Windjuelandet, Ringsaker, Province of Hedemarken, Norway. Acrotreta schmalenseei. 323c [Brogger, 1882, p. 44]. (For stratigraphic position and association, see p. 144.) Passage beds between the Upper Cambrian and the Ordovician: Ceratopyge limestone in the Christiania region, Norway. Lingulella lepis. 323d [Christiania LTniversity Mineral Institute collections]. (For stratigraphic position and association see p. 144.). Passage beds between the Upper Cambrian and the Ordovician: Ceratopyge limestone (Etage Sa;- of Brog- ger) at Christiania, Norway. Acrotreta seebachi. o The authority for the citation of this iocality was mislaid and could not be traced in time for insertion in this volume. LOCALITIES. 257 323e [Christiania University Mineral Institute collections]. (For stratigraphic position and association, see p. 144.) Passage beds between the Upper Cambrian and the Ordovician: Ceratopyge limestone (Etage 3a;- of Brogger) at Bngervik, in Asker, in the Christiania region, Norway. Acrotreta seebachi. ] r\u 1 /-D ■• „; \ „tj.„„: fThese may not be from the same bed. Obolus (Broggena) saltan.) ■' 323f [Brogger, 1882, pp. 16-17]. (A lower horizon than 323h.) (For stratigraphic position and association, see p. 144.) Passage beds between the Upper Cambrian and the Ordovician: Lower part of the Ceratopyge limestone at Vestfossen, 10 miles (16.1 km.) west-southwest of Christiania, Norway. Dikellocephalus angusticauda Angelin. Nileus limbatus Brogger. Niobe obsoleta Linnarsson. Amphion primigenus Angelin. Cheirurus foveolatus Angelin. Bellerophon (?) norvegicus Brogger. Lingulella lepis. Obolus (Broggeria) salteri. Acrotreta socialis var.?=Acrotreta seebachi. Eoorthis christianiK=Eoorthis daunus. Triarthrus angelini Linnarsson. Parabolinella rugosa Brogger. Ceratopyge forScula Sars. 323g [Christiania University Mineral Institute collections]. (For stratigraphic position and association, see p. 144.) Passage beds between the Upper Cambrian and the Ordovician: Ceratopyge limestone (Etage 3a;- of Brogger) at Vaekkero, in the Chi'istiania region, Norway. Acrotreta seebachi. 32311 [Brogger, 1882, p. 17]. (A higher horizon than 323f.) (For stratigraphic position and association, see p. 144.) Passage beds between the Upper Cambrian and Ordovician: Blue Ceratopyge limestone at Vestfossen, 10 miles (16.1 km.) west-southwest of Christiania, Norway. Conophrys pusilla Sars. Dikellocephalus serratus Sars and Boeck. Symphysurus angustatus Sars and Boeck. Niobe insignis Linnarsson. Niobe obsoleta Linnarsson. Megalaspis cf . stenorachis Angelin. Hai'pides rugosus Sars and Boeck. Remopleurides dubius Linnarsson. Holometopus (?) elatifrons Angelin. Lingulella lepis. Lingula sp. Obolus (Broggeria) salteri. *Acrothele ceratopygarum (U. S. National Museum also). Acrotreta sagittalis var. Acrotreta socialis var. = Acrotreta seebachi. Jloorthis christianise=Eoorthis daunus. Agnostus sidenbladhi Linnarsson. Triarthrus angelini Linnarsson. Ceratopyge forficula Sars. 323i [Brogger, 1882, desc. of PI. X]. (For stratigraphic position and association, see p. 144.) Passage beds between the Upper Cambrian and the Ordovician: Phyllograptus slate at Krekling, in Sandsviir, Norway. Obolus (Broggeria) salteri. 323] [Brogger, 1882, p. 44]. (For stratigraphic position and association, see p. 144.) Passage beds between the Upper Cambrian and the Ordo-\acian: Ceratopyge limestone at Tosterup, 7.5 miles (12 km.) north-northeast of Ystad, Province of Malmohus, Sweden. Obolus (Broggeria) salteri. 323k [Brogger, 1882, p. 44]. (For stratigraphic position and association, see p. 145.) LTpper Cambrian: Ceratopyge slate at Tosterup, 7.5 miles (12 km.) north-northeast of Ystad, Province of Malmohus, Sweden. Obolus (Broggeria) salteri. 323 1 (references follow species). (For stratigraphic position and association, see p. 145.) Upper Cambrian: Etage 2b at Toien, about 1 mile (1.6 km.) northeast of Christiania, Norway. Orusia lenticularis [U. S. National Museum and Brogger, 1882, p. 48]. Parabolina spinulosa [Brogger, 1882, p. 48]. 323m (references follow species). (For stratigraphic position and association, see p. 145.^ 2b at Oslo, about 1 mile (1.6 km.) southeast of Christiania, Norway. Orusia lenticularis [U. S. National Museum and Brogger, 1882, p. 4]. Parabolina spinulosa [Brogger, 1882, p. 4]. 323n [Brogger, 1882, p. 48]. (For stratigraphic position and association, see p. 145.) Upper Cambrian: Etage 2b at Vestfossen, 10 miles (16.1 km.) west-southwest of Christiania, Norway. Orusia lenticularis. Peltura scarabeeoides. Upper Cambrian: Etage 323o [Brogger, 1882, p. 4]. (For stratigraphic position and association, see p. 145.) the city of Christiania, Norway. Orusia lenticularis. Parabolina spinulosa. 62667°— VOL 51, pt 1—12 17 Upper Cambrian : Etage 2b in 258 CAMBRIAN BRACHIOPODA. 323p (references follow species). (For stratisraphic position and association, see p. 145.) Upper Cambrian: Etage 2b at Slenimestad, in Roken, about 3 miles (4.8 km.) southwest of Christiania, Norway. Orusia lenticularis [U. S. National Museum and Brogger, 1882, p. 4]. Parabolina spinulosa [Brogger, 1882, p. 4]. 323q [Brogger, 1882, p. 101]. (For stratigraphic position and association, see p. 145.) Upper Cambrian: Etage 2b at Kartveit, in the Christiania region, Norway. Orusia lenticularis. Parabolina spinulosa. 323r [Brogger, 1882, p. 4]. (For stratigraphic position and association, see p. 145.) Upper Cambrian: Etage 2b at Krekling, in Sandsvar, Norway Orusia lenticularis. Parabolina spinulosa. 323s [Brogger, 1882, p. 4]. (For stratigraphic position and association, see p. 145.) Upper Cambrian: Etage 2b at Gjogrefos, in Sandsvar, Norway. Orusia lenticularis. Parabolina spinulosa. 323t [Brogger, 1882, p. 4]. (For stratigraphic position and association, see p. 145.) Upper Cambrian: Etage 2b in Hedemarken, east of Lake Mjosen (Miosen), about 40 miles (64 km.) north-northeast of Christiania, Norway. Orusia lenticularis. Parabolina spinulosa. 323u [Brogger, 1882, p. 4]. (For stratigraphic position and association, see p. 145.) Upper Cambrian: Etage 2b at Oxna (Oksna), valley of Glommen River, eastern Norway. Orusia lenticularis. Parabolina spinulosa. 323v [Davidson, 1869, p. 231]. (For stratigraphic position and association, see p. 145.) Upper Cambrian: At Ege- berg (about 1.5 miles (2.4 km.) southeast of Christiania?), Norway. *Orusia lenticularis. 323w (references follow species). (For stratigraphic position and association, see p. 145.) Upper Cambrian: Black argillaceous shale of "Etage 3a/3" at Christiania, Norway. Obelus sp. (U. S. National Museum). Obolus (Broggeria) salteri (Univ. Mineral Inst., Christiania, Noi-way). *Eoorthis wimani (U. S. National Museum). 323x [U. S. National Museum]. (For stratigraphic position and association, see p. 145.) Upper Cambrian: Cera- topyge slate at Russelokken, near Christiania, Norway. *Eoorthis christianise. 323y [U. S. National Museum]. (For stratigraphic position and association, see p. 145.) Upper Cambrian: Cera- topyge slate at Toien, about 1 mile (1.6 km.) northeast of Christiania, Norway. Eoorthis christianise. 323z [U. S. National Museum]. (For stratigraphic position and association, see p. 144.) Passage beds between the Upper Cambrian and the Ordovician: Ceratopyge limestone at Toien, about 1 mile (1.6 km.) northeast of Christiania, Norway. *Eoorthis daunus. 324 [Kjerulf , 1873, pp. 73 and 83]. (For stratigraphic position and association, see p. 146.) Lower Cambrian : Green shales with interbedded calcareous sandstone at Tomten, in Ringsaker, near Lake Mjosen, Province of Hedemarken, Norway. Holmia kjerulfi (Brogger). Arionellus. Lingulella sp. (U. S. National Museum). Obolella mobergi. Obolella (Glyptias) favosa. 324a [U. S. National Museum]. (For stratigraphic position and association, see p. 146.) Middle Cambrian: Shales of Etage Ic [Brogger] at Skrena, Skiensdalen, Norway (W. C. Brogger, 1877). Acrothele coriacea. 324b [U. S. National Museum]. (For stratigraphic position and association, see p. 146.) Middle Cambrian: Shales of Etage Ic [Brogger] at Krekling, in Sandsvar, Norway (W. C. Brogger, 1877). Acrothele coriacea. Agnostus nudus. LOCALITIES. 259' 324c [TJ. S. National Museum]. (For stratigraphic position and association, see p. 145.) Middle Cambrian: Shales of Etage Id [Brogger] at Krekling, in Sandsvar, Norway (W. C. Brogger, 1877). Micromitra (Iphidella) ornatella. Acrothele coriacea. 324d.'s (For stratigraphic position and association, see p. 145.) Middle Cambrian : At Windjuelandet, Ringsaker, Province of Hedemarken, Norway. Lingulella ferruginea. 325 (references follow species). (For stratigraphic position and association, see p. 131.) Upper Cambrian: Arena- ceous shales, possibly from the horizon of the Peltura fauna (Division C3b), on McAdam shore, East Bay, east of Bras d'Or Lake, in southeastern Cape Breton, Nova Scotia. Ctenopyge pecten [Matthew, 1903, p. 230]. Pai-abolina dawsoni pMatthew, 1903, p. 224]. Peltura scarabseoides [Matthew, 1903, p. 230]. *Obolus (Westonia) escasoni [Matthew, 1903, p. 208]. *Agnostus trisectus germanus [Matthew, 1903, p. 221]. *Agnostus trisectus ponepunctus [Matthew, 1903, p. 221]. ♦Spheerophthalmus fletcheri [Matthew, 1903, p. 228]. 325a (references follow species). (For stratigraphic position and association, see p. 131.) Middle Cambrian: Shales of Division C2c of Matthew's [1903, p. 49] Bretonian on the eastern slope of the valley of McNeil Brook, on the road to Trout Brook, in the Mira River valley, eastern Cape Breton, Nova Scotia. *Lingulella flumenis [Matthew, 1903, p. 190]. | *Acrotreta cf. socialis [Matthew, 1903, p. 184]=Acrotreta "Lingulella rotunda [Matthew, 1903, p. 199]. | sp. undt. 325b [Matthew, 1903, desc. of PL XV]. (For stratigraphic position and association, see p. 131.) Upper Cambrian: Sandy shales of Division C3a of Matthew, Escasonie shore. East Bay, east of Bras d'Or Lake, in southeastern Cape Breton, Nova Scotia. *Lingulella laevis grandis. 325c [U. S. National Museum]. (For stratigraphic position and association, see p. 132.) Middle Cambrian: Sand- stone on the shore of Bras d'Or Lake, eastern Cape Breton, Nova Scotia. Lingulella rotunda. 326 [U. S. National Museum]. Lower Ordovician: Limestone pebbles on the beach on the northern shore of Marthas Vineyard, Mass. Obolus (Westonia) rogersi. Lingulella bella. 326a [Grabau, 1900, p. 613]. Lower Ordovician: Limestone pebbles in a Carboniferous conglomerate north of Fall River, Bristol County, Mass. Obolus (Westonia) rogersi. I Obolus (Lingulobolus) spissus. Obolus (Lingulobolus) affinis. | Scolithus linearis Haldemann. 326b [Grabau, 1900, p. 617]. Middle Cambrian: Braintree slate, below high tide, about 100 feet (30.5 m.) east of the quarry at East Braintree, Abington quadrangle (U. S. G. S.), Norfolk County, Mass. *Aerothele gamagei. 326o [Boston Society Natural History; casts in U. S. National Museum]. Lower Cambrian: "Nahant limestone,"' Pulpit Rock, Nahant, Essex County, Mass. *Acrothele woodworthi. 326d [Grabau, 1900, p. 610]. Lower Cambrian: "Station 2," near North Attleboro, Bristol County, Mass. Obolella atlantica. Obolella crassa. Scenella reticulata Billings. Platyceras primeevum Billings. Stenotheca abrupta (Shaler and Foerste). Stenotheca curvirostra (Shaler and Foerste). Hyolithes quadricostatus (Shaler and Foerste). Hyolithes americanus Billings. 326e [Grabau, 1900, p. 610]. Lower Cambrian: Dark purplish siliceous shales on Pearl Street, North Weymouth, Norfolk County, Mass. Orthotheca emmonsi (Ford). Aristozoe?. Olenellus walcotti (Shaler and Foerste). Microdiscus bellimarginatus (Shaler and Foerste). Microdiscus lobatus (Hall). Strenuella strenua (Billings). Ptychoparia? attleborensis (Shaler and Foerste). Obolella atlantica. Urotheca pervetus Matthew. Olenellus (Holmia) broggeri (Walcott)=Callavia crosbyi Walcott. Olenellus sp. BuiT=Callavia biuri Walcott. Olenellus (Mesonacis) asaphoides Emmons?=Callavia crosbyi Walcott. Metadoxides magnificus? Matthew=Callavia crosbyi Wal- cott. Microdiscus cf . helena Walcott. Strenuella strenua (Billings). Trails. 1 The authority for the citation of this locality was mislaid and could not be traced in time for insertion in this volume. 260 CAIMBRIAN BRACHIOPODA. 826f (references follow species). Lower Cambrian: One-half mile (O.S km.) south of North Weymouth [Burr, 1900, p. 42], Norfolk County, Mass. Obolella atlantica [Burr, 1900, p. 47]. Obolella sp. [Buit, 1900, p. 48]. Olenellus (Holmia) broggeri [Burr, 1900, p. 43]=Callavia crosbyi Walcott. Olenellus (Mesonacis) asaphoides [Burr, 1900, p. 45]=Cal- lavia crosbyi Walcott. Olenellus sp. [Burr, 1900, p. 45]=Callavia burri Walcott. Metadoxides magnificus? [Burr, 1900, p. 46]=Callavia crosbyi Walcott. Agraulos (Strenuella) strenuus nasutus [Burr, 1900, p. 46]. Microdiscus cf. helena [Burr, 1900, p. 47]. Leperditia cf. solitaria [Burr, 1900, p. 47]. Urotheca pervetus [Burr, 1900, p. 48]. Orthotheca cylindrica [Burr, 1900, p. 48]. 326g (references follow species). Lower Cambrian: Limestones at East Poiat, Nahant, Essex County, Mass. Micromitra (Paterina) bella [Grabau, 1900, p. 618]. Obolella crassa [Grabau, 1900, p. 620]. 327 [U. S. National Museum]. Upper Cambrian: Arenaceous limestone east of Gold Camp, Caballos Mountains, Sierra County, N. Mex. (W. T. Lee, 1905). Lingulella acutangula?. Eoorthis desmoplema. Obolus sinoe. Obolus sinoe?. Obolus (Westonia) stoneanus. 327a [U. S. National Museum]. Upper Cambrian: Arenaceous limestone about 500 feet (152 m.) above the base of the Cambrian, in McKinley Canyon, Caballos Mountains, Sien'a County, N. Mex. (W. T. Lee, 1905). Obolus (Westonia) stoneanus. 327b [U. S. National Museum]. Upper Cambrian: Arenaceous limestone near the base of the section on the south side of Cerro CuchUlo, Caballos Mountains, Sierra County, N. Mex. (W. T. Lee, 1905). Obolus (Westonia) stoneanus. 3270 [U. S. National Museum]. Upper Cambrian: Arenaceous limestone in the Caballos Mountains, Sierra County, N. Mex. (W. Lindgren, 1905). Obolus (Westonia) stoneanus. 328 [Whitfield, 1882, p. 172]. Upper Cambrian: Upper layers of the "St. Croix sandstone" near the north end of De\'ils Lake, Sauk County, Wis. *Syntrophia barabuensis. 328a [U. S. National Museiim]. Upper Cambrian: "St. Croix sandstone" 4 miles (6.4 km.) north of Winfield, Jefferson County, Wis. Lingulella similis. 328b [Sardeson, 1896, p. 95]. Upper Cambrian: St. Lawrence formation at Osceola, Polk County, Wis. Obolus (Westonia) am'ora. 328c [U. S. National Museum]. Upper Cambrian: "St. Croix sandstone" at Alma, Buffalo Coimty, Wis. Dicellomus pclitus. Billingsella coloradoensis. Ptychoparia diademata (Hall). 328d [^Tiitfield, 1882, p. 171]. Upper Cambrian: "St. Croix sandstone " at Berlin, Green Lake County, Wis. Billingsella coloradoensis. 328e [U. S. National Museum]. Middle Cambrian: "St. Croix sandstone" at St. Croix Falls, Polk County, Wis. (See p. 159.) Obolus matinalis. Lingulella (Lingulepis) acuminata. *Acrotreta signalis. 328f [Hall, 1863, p. 128]. Upper Cambrian: Sandstone at the falls of St. Croix River, Polk County, Wis. Obolus (Westonia) stoneanus. 328g (references follow species). Middle Cambrian: "St. Croix sandstone," Wisconsin shore of Mississippi River, near Trempealeau, Trempealeau County, Wis. (See p. 159.) Conocephalites chippewaensis [Hall, 1863, p. 134]. Hyolithes primordialis [Hall, 1863, p. 134]. Lingulella ampla (U. S. National Museum). Dicellomus politus [Hall, 1863, p. 134]. Conocephalites iowensis [Hall, 1863, p. 134]. 328h[Owen, 1852, p. 583, and U. S. National Museum]. Upper Cambrian: Silico-calcareous layers of Flbof Owen's section at the falls of the St. Croix, Polk County, Wis. *Obolus matinalis. Lingulella (Lingulepis) acuminata. LOCALITIES. 261 3281 [U. S. National Museum]. Upper Cambrian: "St. Croix sandstone" 0.33 mile (0.5 km.) west of the rail- way station, Lodi, Columbia County, Wis. Finkelnburgia osceola. 328j [U. S. National Museum]. Upper Cambrian: "St. Croix sandstone" on Willow River, near Hudson, St. Croix County, Wis. Obolus mickwitzi. 328k [Whitfield, 1877, p. 51]. Upper Cambrian: "St. Croix sandstone " at Roche a Cris Bluff, Adams Countj-, Wis. *Syntrophia primordialis. 3281 [U. S. National Museum]. (See 328i.) Upper Cambrian: "St. Croix sandstone" near Lodi, Columbia County, Wis. Obolus (Westonia) aurora. 328IU [U. S. National Museum]. Upper Cambrian: Sandstone 1 mile (1.6 km.) south of Osceola, Polk County, Wis. (F. W. Sardeson, 1891). Obolus (Westonia) stoneanus. 328n[U. S. National Museum]. Upper Cambrian: "St. Croix sandstone" 2 miles (3.2 km.) south of Osceola, Polk County, Wis. Lingulella similis. 328p [U. S. National Museum]. (See 85x.) Upper Cambrian: "St. Croix sandstone" at Mazomanie, Dane County, Wis. (J. Hall). Obolus (Westonia) aurora. 328q [U. S. National Museum]. Upper Cambrian: "St. Croix sandstone " in quarry at Ableman, Sauk County, Wis. (J. F. James, 1889). Eoorthis remnicha. 329 [Hague, 1877, p. 405]. (For stratigraphic position and association, see p. 149.) Middle Cambrian: Green shales in a canyon about 7 miles (11.2 km.) north of Brigham (near the village of "Calls Fort" [Hague, 1877, p. 405]), Boxelder County, Utah. *Obolus (Westonia) ella. I Ptychoparia quadrans (Hall and Whitfield). Olenoides wasatchensis (Hall and Whitfield). | Dikellocephalus gothicus=01enoides wasatchensis. 329a [U. S. National Museum]. (For stratigraphic position and association, see p. 148.) Upper Cambrian: Lime- stone on Ute Peak, in the Wasatch Mountains, east of Cache Valley, Cache County, Utah. Syntrophia nundina?. 329b [U. S. National Museum]. (For stratigraphic position and association, see p. 155.) Middle Cambrian: Thin- bedded limestone collected by the Wheeler survey in Utah. Dicellomus politus. 329c [U. S. National Museum]. (For stratigraphic position and association, see p. 151.) Middle Cambrian: In Weber Canyon, about 2.5 miles (4 km.) northeast of Peterson, Morgan County, Utah. Obolus (Westonia) ella. 329d [U. S. National Museum]. (For stratigraphic position and association, seep. 154.) Upper Cambrian: Lime- stone near Fish Spring, Fish Spring Range, Juab County, Utah. Acrotreta pyxidicula. 329e [U. S. National Museum]. (For stratigraphic position and association, see p. 158.) Middle Cambrian: Shales in East Canyon, above Ophir, Oquirrh Range, Tooele County, Utah (40th Parallel Survey). Obolus (Westonia) ella. 330 [Hall, 1851, p. 204]. Upper Cambrian: Sandstone on Taquamenon Bay, Chippewa County, Mich. Lingulella (Lingulepis) acuminata. 330a [Hall, 1851, p. 204]. Upper Cambrian: Sandstone on Escanaba River, northern Michigan. Lingulella (Lingulepis) acuminata. 330b [U. S. National Museum]. Upper Cambrian: Sandstone at Iron Mountain, Dickinson County, Mich. (W. S. Bayley, 1902). Lingulella (Lingulepis)' acuminata. 331 [U. S. National Museum]. Upper Cambrian: Rogersville shale 1 mile (1.6 km.) south of Fletcher, Russell County, Va. Obolus lambom' 262 CAilBRIAN BRACHIOPODA. 332 [Kayser, 1883, p. 35]. Upper Cambrian: Limestone at Saimaki, Liaotung, China. *Obolus? sp. undt. f. Lingulella da^-isi. 332a [Kayser, 1883, p. 34]. Upper Cambrian: At Taling, Liaotung, China. *Eoorthis linnarssoni. 333 (references follow species). (For stratigraphic position and association, see p. 158.) Middle Cambrian: Shales on the dump of the Abe Lincoln mine, near Pioche, Lincoln County, Nov. Micromitra pannula [Pack, 1906, p. 296]. Obolus (Westonia) ella [Pack, 1906, p. 295]. Lingulella genei [Pack, 1906, p. 29-5] = Lingulella dubia. Eocystites longidactylus [Pack, 1906, p. 294]. Bathyuriscus howelli [Pack, 1906, p. 297]. Bathyuriscus productus [Pack, 1906, p. 297]. Zacanthoides typicalis [Pack, 1906, p. 299]. 333a (references foUow species). (For stratigraphic position and association, see p. 158.) Middle Cambrian: Shales on the dump of the Himon mine, near Pioche, Lincoln County, Nev. Obolus (Westonia) ella [Pack, 1906, p. 295]. 1 Bathyiuiscus productus [Pack, 1906, p. 297]. Bathyuriscus howelli [Pack, 1906, p. 297]. I Ptychoparia piochensis [Pack, 1906, p. 298]. 333b (references follow species). (See 7k.) (For stratigraphic position and association, see p. 158.) Middle Cam- brian: Shales on the dump of the Half-moon mine, near Pioche, Lincoln County, Nev. Obolus (Westonia) ella [Pack, 1906, p. 295]. Bathyuriscus howelli [Pack, 1906, p. 297]. Ptychoparia piochensis [Pack, 1906, p. 298]. Ptychoparia kempi [Pack, 1906, p. 298]. Zacanthoides typicalis [Pack, 1906, p. 299]. Zacanthoides grabaui [Pack, 1906, p. 300]. 334 (references follow species). (For stratigraphic position and association, see p. 145.) Middle Cambrian: Limestones of Paradoxides forchhammeri zone on Bomholm Island, Denmark. Acrotreta socialis [Wallerius, 1895, p. 66]=Acrotreta schmalenseei. Acrotreta socialis [Linnarsson, 1876, p. 18]= Acrotreta schmalenseei. 334a [Gronwall, 1902, p. 39]. (For stratigraphic position and association, see p. 146.) Middle Cambrian: Lime- stones of the Conocoryphe exsulans zone at Borregaard, Bomholm Island, Denmark. Acrothele intermedia. 334b [Gronwall, 1902, p. 40]. (For stratigraphic position and association, see p. 145. Middle Cambrian: Andrarum limestone at Borregaard, Bomholm Island, Denmark. Acrothele coriacea. 334c [Gronwall, 1902, p. 40]. (For stratigraphic position and association, see p. 146.) Middle Cambrian: In the Paradoxides tessini zone at Borregaard, Bomholm Island, Denmark. Acrothele coriacea. 334d [Gronwall, 1902, p. 40]. (For stratigraphic position and association, see p. 146.) Middle Cambrian: In the zone with Agnostus parvifrons at Borregaard, Bomholm Island, Denmark. Acrothele coriacea. 334e [Gronwall, 1902, p. 40]. (For stratigraphic position and association, see p. 145.) Middle Cambrian: Andrarum limestone at Laesa^, Bomholm Island, Denmark. Acrothele coriacea. 334f [U. S. National Museum]. (For stratigraphic position and association, seep. 145.) Middle Cambrian: Lime- stone on Bomholm Island, Denmark. Acrothele coriacea. 334g [Seebach, 1865, pp. 340 and 341]. (For stratigraphic position and association, see p. 145.) Middle Cambrian: On Bomholm Island, Denmark. *Acrotreta socialis. Paradoxides. Agnostus pisiformis Linnarsson. Agnostus bituberculatus. Agnostus? punctuosus. Anomocare difforme Angelin. 33411 [U. S. National Museum]. (See 16h.) (For stratigraphic position and association, seep. 145.) Middle Cam- brian: Limestones of the Paradoxides forchhammeri zone at Borregaard, Bomholm Island , Denmark (University of Copenhagen). Acrothele coriacea. Acrotreta sagittalis. 335a. [U. S. National Museum]. (See 360b.) Passage beds between the Cambrian and the Ordovician: Red- dish sandstone on Cement Creek, 3 miles (4.8 km.) north of Hot Springs and 8 to 10 miles (12.8 to 16.1 km.) southeast of Crested Butte, Ouray County, Colo. *Obolus loperi. LOCALITIES. 263 336 [F. Schmidt, personal commimicatioii, 1906]. (For stratigraphic position and association, see p. 143.) Ordo- vician: Echinosphserites limestone, horizon Cla, at Popowka, near St. Petersburg, Russia. •Acrotreta aubconica. 336a (references follow species). (For stratigraphic position and association, see p. 143.) IlpperCambrian: Oftofus sandstone at Podolova (Putalova?), on Ijora (Ischora) River, Government of St. Petersburg, Russia. OboluB apollinis [Eichwald, 1860, p. 926]. Obolus apollinis ingricus [Eichwald, 1S60, p. 926]. Keyserlingia buchi [Eichwald, 1860, p. 914]. 336b [Eichwald, 1860, p. 925]. (For stratigraphic position and association, see p. 143.) Upper Cambrian: Obolus sandstones on Odensholm Island, about 5-5 miles (88.6 km.) west of Reval, Government of Esthonia, Russia. Obolus apollinis. 336c [Eichwald, 1860, p. 926]. (For stratigraphic position and association, seep. 143.) Upper Cambrian: Obolus sandstone at Reval, Government of Esthonia, Russia. Obolus apollinis. Obolus apollinis ingricus. 336d [Eichwald, 1S60, p. 929]. (For stratigraphic position and association, see p. 143.) Passage beds between the Upper Cambrian and the Ordovician: Orthoceratite limestone at Reval, Government of Esthonia, Russia. Obolus (Acritis) antiquissimus. 336e (references follow species). (For stratigraphic position and association, see p. 143.) Passage beds between the Upper Cambrian and the Ordo\'ician: Orthoceratite limestone, at Pultowa, near St. Petersburg, Russia. Obolus (Acritis) antiquissimus [Eichwald, 1860, p. 929]. Siphonotreta unguiculata [Eichwald, 1860, p. 916]. Siphonotreta verrucosa [Eichwald, 1860, p. 916]. 336f [Eichwald, 1860, p. 927]. (For stratigraphic position and association, see p. 143.) Passage beds between the Upper Cambrian and the Ordovician: In the pyroxene-bearing sands in the Orthoceratite limestone beds at Reval, Government of Esthonia, Russia. Obolus (Mickwitzella) siluricus. 336g (references follow species). (For stratigraphic position and association, see p. 143.) Ordovician: Limestone in the vicinity of Zarskoe Selo, Government of St. Petersburg, Russia. *Volborthia recurva [Kutorga, 1848, p. 278]. 1 _, . ^ , i^ _i-l , , c,. , . ^ • 1 i r^ ^ no..o ootn ^ These species may not be from the same bed. Siphonotreta unguiculata [Kutorga, 1848, p. 265]. | 3361i [U.S. National Museum] . ( For stratigraphic position and association, see p . 143 . ) Upper Cambrian : Ungulite grit at Baltischport, Esthonia, Russia. *Schizambon? esthonia. 3361 [Mickwitz, 1896, p. 147]. (For stratigraphic position and association, see p. 144.) Upper Cambrian: Sand- stone below the Obolus conglomerate proper at Reval, Government of Esthonia, Russia. Obolus triangularis. 336j [U. S. National Museum]. (For stratigraphic position and association, see p. 143.) Upper Cambrian: Obolus sandstone at Staroja Ladoga, Government of Novgorod, Russia. Obolus apollinis maximus. 336k [Eichwald, 1860, p. 925]. (For stratigraphic position and association, see p. 143.) Upper Cambrian: Obolus sandstone on the bank of Volkhof (Wolchow) River, east of St. Petersburg, Russia. Obolus apollinis. 3361 [Eichwald, 1860, p. 925]. (For stratigraphic position and association, see p. 143.) Upper Cambrian: Obolus sandstone on the bank of Sjass (Sias) River, near Lake Ladoga, Government of St. Petersburg, Russia. Obolus apollinis. 336m [Eichwald, 1860, p. 925]. (For stratigraphic position and association, seep. 143.) Upper Cambrian: Obolus sandstone at Baltischport, about 30 miles (48 km.) west of Reval, Government of Esthonia, Russia. Obolus apollinis. 336n [de Verneuil, 1845, p. 289]. (For stratigraphic position and association, see p. 143.) Upper Cambrian: On Ijora (Ischora) River, Government of St. Petersburg, Russia. *Keyserlingia buchi. 3360 [U. S. National Museum]. (For stratigraphic position and association, see p. 143.) Upper Cambrian: Ungu- lite grit, Koporje, Government of St. Petersburg, Russia. Obolus (Schmidtia) celatus. Helmersenia ladogensis. Keyserlingia buchi. 264 CMIBRIAN BRACHIOPODA. 336p [U. S. National Museum]. (For stratigraphic position and association, see p. 143.) Upper Cambrian: Ungu- lite grit, Kunitz, Government of Pskow, Russia. Obolus (Schmidtia) celatus. I Helmersenia ladogensis. Obolus sp. I Keyserlingiabuchi. 336q [Jeremejew, 1856, pp. 73 and 80]. (For stratigraphic position and association, see p. 143.) Upper Cambrian:. UnguUte sandstone near Ladoga, Government of St. Petersburg, Russia. *Helmersenia ladogensis. 336r [Mickwitz, 1896, p. 137]. (For stratigraphic position and association, see p. 143.) Upper Cambrian: Obolus- sandstone in the entire region between the Volkhof (Wolchow) and Sjass (Sias) rivers on the east and Baltischport on the west, governments of Novgorod, St. Petersburg, and Esthonia, Russia. Obolus apollinis. 336s (references follow species) . (For stratigraphic position and association, see p. 143.) Upper Cambrian : Obolus sandstone at Narwa, Government of Esthonia, Russia. Obolus apollinis (U. S. National Museum). Obolus apollinis ingricus [Eichwald, 1843, p. 146]. 336t [Eichwald, 1843, p. 146]. (For stratigraphic position and association, see p. 143.) Upper Cambrian: OboluS' sandstone at Wiems, 5 miles (8 km.) north-northeast of Reval, Government of Esthonia, Russia. Obolus apollinis. Obolus apollinis ingricus. 336u [Eichwald, 1860, p. 925]. (For stratigraphic position and association, see p. 143.) Upper Cambrian: Obolus sandstone on the bank of Louga (Luga) River, southwest of St. Petersburg, Russia. Obplus apollinis. 336v [Gagel, 1890, desc. of PI. I]. (For stratigraphic position and association, see p. 143.) Ordovician: Echino- sphserites limestone at Reval, Government of Esthonia, Russia. Siphonotreta unguiculata. 336w (references follow species). (For stratigraphic position and association, see p. 143.) Ordovician: Near Paw- lowsk, near St. Petersburg, Russia. Siphonotreta unguiculata [Eichwald, 1840, p. 140 (26)]. Siphonotreta verrucosa [Eichwald, 1840, p. 141 (27)]. 336x [de Verneuil, 1845, p. 287]. (For stratigraphic position and association, see p. 143.) Ordovician: In the Archangel quarry, on Volkhof (Wolchow) River, east of St. Petersburg, Russia. Siphonotreta unguiculata. 336y [U. S. National Museum]. (For stratigraphic position and association, see p. 143.) Passage beds between the Upper Cambrian and the Ordovician: Glauconite limestone at Popowka, near St. Petersburg, Russia. Siphonotreta unguiculata. Siphonotreta verrucosa. 336z [Schmidt, 1861, pp. 218 and 248]. (For stratigraphic position and association, see p. 143.) Passage beds between the Upper Cambrian and the Ordovician: Orthoceratite limestone ("Vaginatenkalk") at Narwa, Government of Esthonia, Russia. Siphonotreta unguiculata. 337 [Schmidt, 1861, pp. 218 and 248]. (For stratigraphic position and association, see p. 143.) Passage beda between the Upper Cambrian and the Ordovician: Orthoceratite limestone ("Vaginatenkalk") at Erras, 85 miles (137 km.) east of Reval, Government of Esthonia, Russia. Siphonotreta unguiculata. 337a [Schmidt, 1861, pp. 218 and 248]. (For stratigraphic position and association, see p. 143.) Passage beds, between the Upper Cambrian and the Ordovician: Orthoceratite limestone ("Vaginatenkalk") at Kusal, 25 miles (40 km.) east of Reval, Government of Esthonia, Russia. Siphonotreta unguiculata. 337b [Schmidt, 1861, pp. 218 and 248]. (For stratigraphic position and association, see p. 143.) Passage beds between the Upper Cambrian and the Ordovician: Orthoceratite limestone ("Vaginatenkalk") at Reval, Government of Esthonia, Russia. *Siphonotreta unguiculata." 337c [Schmidt, 1861, pp. 218 and 248]. (For stratigraphic position and association, see p. 143.) Passage beds between the Upper Cambrian and the Ordovician: Orthoceratite limestone ("Vaginatenkalk") on Odens- holm Island, 55 miles (88.6 km.) west of Reval, Government of Esthonia, Russia. Siphonotreta unguiculata. a May be tlie type locality. Eichwald [1829, p. 274] gives it as " limestone at Reval." LOCALITIES. 265 337d. [Schmidt, 1861, p. 218]. (For stratigraphic position and association, see p. 143.) Ordovician: "Brandschie- fer" at Salla, near Erras, 85 miles (137 km.) east of Reval, Government of Esthonia, Russia. Siphonotreta unguiculata. 337e [Schmidt, 1861, p. 218]. (For stratigraphic position and association, see p. 143.) Ordovician: "Jewesche Schicht" at Altenhof, near Poddrus, 55 miles (88.6 km.) east of Reval, Government of Esthonia, Russia. Siphonotreta unguiculata. 337f [Schmidt, 1861, pp. 218 and 248]. (For stratigraphic position and association, see p. 143.) Passage beds^ between the Upper Cambrian and the Ordovician: Orthoceratite limestone ("Vaginatenkalk") at Tursel 15 miles (24.2 km.) west of Narwa, Government of Esthonia, Russia. Siphonotreta verrucosa. 337g [Schmidt, 1861, pp. 218 and 248]. (For stratigraphic position and association, see p. 143.) Passage beds between the Upper Cambrian and the Ordovician: Or£/iocera£Ue limestone ("Vaginatenkalk") at Chudleigh, 25 miles (40 km.) west of Narwa, Government of Esthonia, Russia. Siphonotreta verrucosa. 33711 [Eichwald, 1860, p. 929]. (For stratigraphic position and association, see p. 143.) Passage beds between the Upper Cambrian and the Ordovician : Orthoceratite limestone near Reval, Government of Esthonia, Russia. Obolus (Acritis) antiquissimus. 337i [Schmidt, 1861, p. 218]. (For stratigraphic position and association, see p. 143.) Passage beds between the Upper Cambrian and the Ordovician: "Green sand" at Baltischport, Government of Esthonia, Russia. Obolus (Mickwitzella) siluricus. 337j [Fr. Schmidt, personal communication, 1908]. (For stratigraphic position and association, see p. 143.) Ordo- vician: Zone Bllla or .BIII/S, characterized by Asaphus raniceps, a little above the zone with Asaphus expansus, in the Orthoceratite limestone at Obookhov (Obuchow), on Volkhof (Wolchow) River, Govern- ment of St. Petersburg, Russia. Volborthia recurva. 337k [Eichwald, 1860, p. 916]. (For stratigraphic position and association, see p. 143.) Passage beds between the Upper Cambrian and the Ordovician: Orthoceratite limestone on the banks of Volkhof (Wolchow) River, near Lake Ladoga, near St. Petersburg, Russia. Siphonotreta unguiculata. , 3371 [Eichwald, 1860, p. 916]. (For stratigraphic position and association, see p. 143.) Passage beds between the- Upper Cambrian and the Ordovician: Orthoceratite limestone at Baltischport, west of Reval, Government of Esthonia, Russia. Siphonotreta unguiculata. 337m [Eichwald, 1860, p. 916, and U. S. National Museum]. (For stratigraphic position and association, see p. 143.) Passage beds between the Upper Cambrian and the Ordovician: Orthoceratite limestone at Popowka, near St. Petersburg, Russia. Siphonotreta unguiculata. Siphonotreta verrucosa. 338 [U. S. National Museum]. (See 29a.) Lower Cambrian: Limestone at Schodack, northeastern corner of Cox- sackie quadrangle (U. S. G. S.), Rensselaer County, N. Y. Acrotreta sagittalis taconica. 338a [U. S. National Museum]. Lower Cambrian: Limestone in the northeast section of Whitehall township,. Whitehall quadrangle (U. S. G. S.), Washington County, N. Y. Acrotreta sagittalis taconica. 338b [U. S. National Museum]. (See 29.) Lower Cambrian: Limestone on Kinderhook Creek, near Stock- port paper mill, Kinderhook quadrangle (U. S. G. S.), Columbia County, N. Y. Acrotreta sagittalis taconica. 338c [U. S. National Museum]. (See 83.) Lower Cambrian: Limestone at Rock Hill schoolhouse, near North. Greenwich, Cambridge quadrangle (U. S. G. S.), Washington County, N. Y. Acrotreta sagittalis taconica. 338d [U. S. National Museum]. (See 36; may be same locality.) Lower Cambrian: Limestone 1 mile (1.6 km.) south of Shushan, Cambridge quadrangle (U. S. G. S.), Washington County, N. Y. Acrotreta sagittalis taconica.) „, . , • „ , , -r,.,,. ,, , . !• These species may not occur m the same bed. Bilhngsella salemensis. J 338e [U. S. National Museum]. Lower Cambrian: Limestone a little west of North Greenwich, Cambridge quad- rangle (U. S. G. S.), Washington County, N. Y. Acrotreta sagittalis taconica. 266 CAMBRIAN BRACHIOPODA. 338f [U. S. National Museum]. Lower Cambrian: Limestone near Argyle, 8 miles (12.8 km.) north of Greenwich, Cambridge quadrangle (U. S. G. S.), Washington County, N. Y. Acrotreta sagittalis taconica. 338g [U. S. National Museum]. Lower Cambrian: Limestone in the town of Greenwich, Cambridge quadrangle (U. S. G. S.), Washington County, N. Y. Acrotreta sagittalis taconica. 338h [U. S. National Museum]. (See Walcott, 1888, pp. 316 and 317, for section.) Lower Cambrian: Limestone on the summit of Bald Mountain, about 2 miles (3.2 km.) northwest of Greenwich, Schuylerville quadrangle (U. S. G. S.), Washington County, N. Y. Botsfordia caelata. Acrotreta sagittalis taconica. Obolella sp. Hyolithellus micans (Billings). Microdiscus speciosus Ford. Olenellus thompsoni (Hall). 3381 [U. S. National Museum]. Ordovician: Shales 1 mile (1.6 km.) west-northwest of South Argyle, near the line between the Schuylerville and Cambridge quadrangles (U. S. G. S.), Washington County, N. Y_ Acrothele pretiosa. 338] [Hall, 1847, p. 4]. Upper Cambrian: Potsdam sandstone near Alexandria Landing, Jefferson County, N. Y. Lingulella (Lingulepis) acuminata. 338k [U. S. National Museum]. (See 72a.) Lower Cambrian: Limestone 2.5 miles (4 km.) southwest of Wynants- kill, Rensselaer County, N. Y. (L, M. Prindle, 1893). Obolus prindlei. 3381 [U. S. National Museum]. (See 39a.) Lower Cambrian: Limestone in the northern part of Saston, 3 miles (4.8 km.) south of Greenwich, Cambridge quadrangle (U. S. G. S.), Washington County, N. Y. Lingulella granvillensis. 338m [U. S. National Museum]. Lower Cambrian: Limestone on the roadside north of schoolhouse No. 4, in the northeast part of Whitehall, Whitehall quadrangle (U. S. G. S.), Washington County, N. Y. Lingulella granvillensis. 338n [IT. S. National Museum]. Lower Cambrian: Western belt of conglomeratic limestone, Rensselaer County, N. Y. Yorkia washingtonensis. Microdiscus lobatus (Hall). 3380 [?]. Lower Cambrian: Shale on Moses Hill, 2 miles (3.2 km.) west of North Greenwich, near the line between the Schuylerville and Cambridge quadrangles (U. S. G. S.), Washington County, N. Y. Obolella crassa. 338p [U. S. National Museum]. Lower Cambrian: Sandy limestone 0.25 mile (0.4 km.) northwest of schoolhouse No. 7, in Greenwich, Cambridge quadrangle (U. S. G. S.), Washington County, N.Y. Obolella chromatica. 338t[ [Hall, 1847, p. 290]. Lower Cambrian: Calcareous beds 2 miles (3.2 km.) northeast of Troy, Troy quad- rangle (U. S. G. S.), Rensselaer County, N. Y. *Obolella crassa. 338r [Billings, 1856, p. 34]. Upper Cambrian: Potsdam sandstone at Keeseville, Essex County, N. Y. Lingulella (Lingulepis) acuminata. 338s [Emmons, 1842, pp. 267 and 268]. Upper Cambrian: Potsdam sandstone at High Bridge, on Ausable River, Essex County, N.Y. *Lingulella (Lingulepis) acuminata. 338t [U. S. National Museum records]. Upper Cambrian: Potsdam sandstone in Ausable Chasm, below Keese- ville, Essex County, N. Y. Lingulella prima, lingulella (Lingulepis) acuminata. 338u [U. S. National Museum records]. Ordovician and Upper Cambrian: In the strata from the upper layers of the Potsdam sandstone to the lower portion of the "Calciferous sand rock" at Chateaugay Falls, Franklin County, N. Y. Lingulella (Lingulepis) acuminata (associated with Ophileta complanata in the upper beds). 338v [U. S. National Museum]. Ordovician: Shale 1 mile (1.6 km.) southwest of Middle Granville, Mettawee quadrangle (U. S. G. S.;, Washington County, N. Y. *Obolus sp. undt. a. LOCALITIES. 267 338w [Hall, 1847, p. 4]. Upper Cambrian: Potsdam eandstone at Hammond, St. Lawrence County, N. Y. lingulella (Lingulepis) acuminata. 338x [TJ. S. National Museum]. Lower Cambrian: Limestone 0.5 mile (0.8 km.) south of Coila, just east of Cam- bridge, Cambridge quadrangle (U. S. G. S.), Washington County, N. Y. (C. D. Walcott, 1886). Lingulella sp. Acrotreta sagittalis taconica. 338y [U. S. National Museum]. Lower Cambrian: Limestone north of Eagle Mills, Rensselaer County, N. Y. (T. N. Dale). Acrotreta sagittalis taconica. 338z [U. S. National Museum]. Ordovician: Limestone on the north side of Bald Mountain, about 2 miles (3.2 km.) northwest of Greenwich, Schuylerville quadrangle (U. S. G. S.), Washington County, N. Y. (F. H. Moffit, 1902). Acrothele pretiosa. 339 [Sardesoa, 1896, pp. 95 and 96]. Lower Ordovician: Oneota dolomite, Stillwater, Washington County, Minn. ^Obolus dolatus. Orthis (Billingsella) pepina=BUlingsella coloradoensis. 339a [Sardeson, 1896, p. 95]. Upper Cambrian: St. Lawrence formation at Otisville, Washington County, Minn. Obolus (Westonia) aurora. 339b [U. S. National Museum]. Upper Cambrian: "St. Croix sandstone" at Areola on St. Croix River, 7 miles (11.2 km.) above Stillwater, Washington County, Minn. Lingulella winona. 339c [U. S. National Museum]. Upper Cambrian: Reeds Landing, foot of Lake Pepin, Wabasha County, Minn. •Obolus (Westonia) aurora. 339d [U. S. National Museum]. (See 82b; maybe same locality.) Upper Cambrian: "St. Croix sandstone" at Taylors Falls, Chisago County, Minn. Obolus matinalis. Lingulella similis. Eoorthis remnicha sulcata. Syntrophia primordialis. 339e [U. S. National Museum]. Middle Cambrian: "St. Croix sandstone" on Mountain Island, Minnesota, in Mississippi River, just above the mouth of Trempealeau River. (See p. 159.) *Lingule]la ampla. Dicellomus politus. 339f [U. S. National Museum]. Upper Cambrian: "St. Croix sandstone" near Minneiska(Miniska), on Mississippi River, near the line between Wabasha and Winona counties, Minn. (F. M. Brown). Obolus matinalis. Billingsella coloradoensis. JFinkelnburgia finkelnburgi. 339g [U. S. National Museum]. Upper Cambrian: "St. Croix sandstone" just below the heda with. Diiellocephaltis minnesotensis near Winona, Winona County, Minn. TJillingsella coloradoensis. I Finkelnburgia osceola corrugata. Finkelnburgia osceola. | Syntrophia primordialis. 339h (references follow species). Upper Cambrian: "St. Croix sandstone " near the mouth of Minneiska (Miniska) River, near the line between Wabasha and Winona counties, Minn. Obolus matinalis [Hall, 1863, p. 130]. Lingulella (Lingulepis) acuminata [Hall, 1863, p. 130]. Orthis pepina [Hall, 1863, p. 135]=BilHngsella coloradoensis. 339i [Owen, 1852, desc. of PI. IB]. Middle Cambrian: Sandstones of Fib of Owen's section, below Mountain Island, in Mississippi River, nearly opposite the old mouth of Black River, southeastern Minnesota. (See p. 159.) *Diceliomus politus. 339] [U. S. National Museum]. Middle Cambrian: Sandstone between the lowest blue shale and the reddish calcareous beds above, at Taylors Falls, Chisago Coimty, Minn. (Chas. Schuchert). (See p. 159.) Lingulella (Lingulepis) acuminata. 339k [U. S. National Museum]. Middle Cambrian: Sandstone near Winona, Winona County, Minn. (See p. 159.) Lingulella (Lingulepis) acuminata. 340 [U. S. National Museum]. (See 5f ,) Middle Cambrian: Limestone in Meagher County, on the road to Wolsey, about 1 mile (1.6 km.) below the divide and 13 miles (21 km.) south of Neihart, Little Belt Mountains quadrangle (U. S. G. S.), Cascade County, Mont. (W. H. Weed, F. B. Weeks, and C. D. Walcott, 1895). -Micromitra pealei. 268 CAMBRIAN BRACHIOPODA. 340a [U. S. National Museum]. (Same horizon as 4u.) Middle Cambrian: Shales near Helena, Jefferson County, Mont. (L. S. Griswold). Obolus (Westonia) ella. 340b [U. S. National Museum]. Upper Cambrian: Limestone at the mouth of Pourmile Creek, probably some- where in the Threeforks quadrangle (U. S. G. S.), Gallatin County, Mont. (A. C. Peale). Eoorthis desmopleura. 340c [U. S. National Museum]. Middle? Cambrian: Dark-red sandstone near the base of the Cambrian at Rawlins, Carbon County, Wyo. (N. H. Darton). Lingulella (Lingulepis) acuminata. 340d [U. S. National Museum]. Middle Cambrian: Limestone near the head of Bear River Canyon, Wyo. (A. C- Peale). Acrotreta attenuata. 340e [U. S. National Museum]. Middle? Cambrian: Shale on the west side of Cable Mountain, Phillipsburg quadrangle (U. S. G. S.), Granite County, Mont. (F. C. Calkins, 1906). Lingulella sp. 340f [U. S. National Museum]. Middle? Cambrian: Lowest beds exposed at the mouth of Bear Creek, Little Belt Mountains, Mont. (W. H. Weed, 1894). Dicellomus politus. 341 [U. S. National Museum]. Upper Cambrian: Near Lansing, Allamakee County, Iowa. *Lingulella winona (also cited from this locality by Hall, 1863, p. 126). Finkelnburgia osceola. 341a [U. S. National Museum]. Upper Cambrian: Sandstone at McGregor, Clayton County, Iowa (F. W. Sardeson, 1899). Lingulella mosia. 342 [collection of J. Miquel]. Middle Cambrian: Shales in Montague Noire, Coulouma, Department of H6rault, France. *Acrothele bergeroni. 342a [collection of J. Miquel]. Passage beds between the Cambrian and the Ordovician, or Lower OrdovicianL Barren quartzitic beds, Coulouma, Department of H6rault, France. *Yorkia? miqueli. 343 [Rogers, 1875, p. 11, mentions specimens from Newport; U. S. National Museum has specimens labeled Narra- gansett Bay]. Lower Ordovician: Limestone pebbles on the beach near Newport and at several points- along the shores of Narragansett Bay, Rhode Island. *Obolus (Westonia) rogersi. 343a [U. S. National Museum]. Upper Cambrian: Limestone pebbles on Checker Beach, near Newport, R. I.. (0. O. Nylander, 1893). Lingulella sp. 1. Lingulella sp. 2. 343b [U. S. National Museum]. Upper Cambrian: Limestone pebble on Sachuset Beach, near Newport, R. I.. Lingulella bella. 344 (references follow species). (For stratigraphic position and association, see p. 133.) Middle Cambrian:: Sandy shales of Division E3b of Matthew's [1903, p. 21] Etcheminian, on Dugald Brook, Indian River,, eastern Cape Breton, Nova Scotia. Obolus lens [Matthew, 1903, p. 81]=Obolus (Palseobolus) bretonensis lens. Lingulella atava [Matthew, 1903, p. 81]. Lingulella [Matthew, 1903, p. 58], Acrothele abavia [Matthew, 1903, p. 81]:=Acrothele avia.. Acrothele avia [Matthew, 1903, p. 81]. 344a (references follow species). (For stratigraphic position and association, see p. 133.) Middle Cambrian: Sandy shales of Division E3c of Matthew's [1903, p. 21] Etcheminian, on Dugald Brook, Indian River,, eastern Cape Breton, Nova Scotia. Lingulella sp. [Matthew, 1903, p. 26]. Acrotreta sp. [Matthew, 1903, p. 26]. Lingulella collicia [Matthew, 1903, p. 26]. Acrothele abavia [Matthew, 1903, p. 26]^Acrothele avia. *Acrothyra proavia [Matthew, 1902b, p. 422]. Bradoria scrutator [Matthew, 1903, p. 163]. 344b (references follow species). (For stratigraphic position and association, see p. 133.) (See 13n''''). Middle' Cambrian: Sandy shales of Division ESd of Matthew's [1903, p. 21] Etcheminian, on Dugald Brook, Indian. River, eastern Cape Breton, Nova Scotia. Lingulella atava [Matthew, 1903, p. 81]. *Obolus (Palseobolus) bretonensis [Matthew, 1903, p. 81]. Acrothele avia [Matthew, 1903, p. 81]. Acrothyra proavia [Matthew, 1903, p. 91]. *Bradorona spectator sequat [Matthew, 1903, p. 81]. LOCALITIES. 269 344o (references follow species). (For stratigraphic position and association, see p. 133.) Middle Cambrian: Sandy shales of Division ESd of Matthew's Etcheminian on Gregwa Brook, Indian River, eastern Cape Breton, Nova Scotia. Obolus (Palseobolus) bretonensis [Matthew, 1903, p. 142]. *Acrothele avia puteis [Matthew, 1903, p. 100]. 344d [Matthew, 1903, p. 82]. (See 13n.) (For stratigraphic position and association, see p. 133.) Middle Cam- brian: Sandy shales of Division E3f of Matthew's [1903, p. 21] Etcheminian, Dugald Brook, Indian River, eastern Cape Breton, Nova Scotia. Lingulella atava. Leptobolus collicia= Lingulella collicia. Leptobolus collicia collis=Lingulella collicia. Acrothele proles. Acrothyra proavia crassa=Acrothyra proavia. Acrothyra proavia prima= Acrothyra proavia. Hyolithes. Leperditia? rugosa. 344e (references follow species). (For stratigraphic position and association, see p. 134.) Middle Cambrian: Shales of Division Eld of Matthew's [1903, pp. 28 and 29] Etcheminian on Boundary Brook, eastern side of the Escasonie Indian Reservation, eastern Cape Breton, Nova Scotia. *Bradorona perspicator major. Bradoria scrutator. Escasona rutellum. *Indiana lippa. Eurypteroid crustacean. Solenopleura bretonensis. Schmidtella? acuta. lingulella cf. collicia [Matthew, 1903, p. 78]. Leptobolus atavus tritavus [Matthew, 1903, p. 78]= Lingulella torrentis. Lingulella (Lingulepis) gregwa [Matthew, 1903, p. 78]. Lingulella (Lingulepis) sp. fMatthew, 1903, p. 78]. Obolus sp. [Matthew, 1903, p. 78]. Acrotreta papUlata [Matthew, 1903, p. 78]=Acrothyra sera. Acrotreta papillata lata [Matthew, 1903, p. 78]=Acro- thyra sera. Orthotheca sp. [Matthew, 1903, p. 78]. 344f [Matthew, 1903, p. 72]. (See 13k.) (For stratigraphic position and association, see p. 135.) Bradorona observator [Matthew, 1903, p. 78]. *Bradorona observator benepuncta [Matthew, 1903, p. 78]. Bradorona perspicator [Matthew, 1903, p. 78]. Bradorona spectator [Matthew, 1903, p. 78]. Bradorona spectator acuta [Matthew, 1903, p. 159]. Bradoria vigilans obesa [Matthew, 1903, pp. 78 and 152]. *Escasona rutellum prima [Matthew, 1903, p. 78; rutel- lum vetus on p. 152]. *Schmidtella (?) pervetus concinna [Matthew, 1903, p. 78]. Middle Cam- brian: Shales of the Coldbrook terrane of Matthew, on Dugald Brook, Indian River, eastern Cape Breton, Nova Scotia. Obolus torrentis. *Lingulella torrentis. Lingulella cf. longovalis=Lingulella cf. triparilis. *Lingulella (Lingulepis?) pumila. Acrotreta papillata prima=Acrothyra sera. Acrothyra signata prima. Hyolithes. *Indiana ovalis prima. *Escasona?? ingens. 344g (references follow species). (For stratigraphic position and association, see p. 134.) (See ISt".) Middle Cambrian: Shales of Division Elc of Matthew's [1903, p. 21] Etcheminian, Dugald Brook, Indian River Valley, Cape Breton, Nova Scotia. 77]=Lingulella Hyolithes [Matthew, 1903, p. 77]. Orthotheca [Matthew, 1903, p. 77]. *Bradorona perspicator maxima [Matthew, 1903, p. 77]. Bradorona spectator [Matthew, 1903, p. 77]. p. 77]. *Bradoria ornata [Matthew, 1903, p. 77]. 95]=Acrothyra Bradoria rugulosa var. [Matthew, 1903, p. 166]. Bradoria vigilans obesa [Matthew, 1903, p. 152]. Crustacean [Matthew, 1903, p. 77]. Lingulella longovalis [Matthew, 1903, p triparilis. Lingulella triparilis [Matthew, 1903, p. 77]. Lingulella cf. tumida [Matthew, 1903, p. 23]. Lingulella (Lingulepis) gregwa [Matthew, 1903 Acrotreta papillata [Matthew, 1903, p. *AcrothyTa signata sera [Matthew, 1903, p. 77]=Acro- thyra sera. Acrothyra signata tarda [Matthew, 1903, p. 77]=Acro- thyra sera. 344h (references follow species). (For stratigraphic position and association, see p. 134.) Middle Cambrian: Sandy layers in the shales of Division Ele of Matthew's [1903, p. 21] Etcheminian, Dugald Brook, Indian River, eastern Cape Breton, Nova Scotia. •Obolus discus [Matthew, 1903, p. 79]=Lingulella tri- parilis. Lingulella longovalis [Matthew, 1903, p. 79]=Lingulella. triparilis. Lingulella cf. tumida [Matthew, 1903, p. 24], Lingulella (Lingulepis) gregwa robusta [Matthew, 1903, p. 79]. Leptobolus sp. [Matthew, 1903, p. 79]. Obolus sp. [Matthew, 1903, p. 79]. Orthotheca sp. [Matthew, 1903, p. 79]. Hyolithes sp. [Matthew, 1903, p. 79]. *Bradorona spectator spinosa [Matthew, 1903, p. 79]. *Indiana ovalis [Matthew, 1903, p. 79]. 270 CAMBRIAN BRACHIOPODA. 344i (references follow species). (See 13 V.) {For stratigraphic position and association, see p. 133.) Middle Cambrian: Sandy shales of Division E3a of Matthew's [1903, p. 21] Etcheminian on Dugald Brook, Indian River, eastern Cape Breton, Nova Scotia. Obolus lens [Matthew, 1903, p. 80]=Obolus (Palseobolus) bretonensis lens. Acrothele abavia [Matthew, 1903, p. 80]=Acrothele avia. Acrothyra proavia [Matthew, 1903, p. 80]. Obolus (Palseobolus) bretonensis [Matthew, 1903, p. 143]. 344j [Matthew, 1903, p. 91]. (For stratigraphic position and association, see p. 133.) Middle Cambrian: Division E3e of Matthew's [1903, p. 21] Etcheminian on the highway at V. McPhees, eastern Cape Breton, Nova Scotia. Acrothyra proavia. 344k (references follow species). (See 13t'.) (For stratigraphic position and association, see p. 134.) Middle Cam- brian: Sandstones of Division Elb of Matthew's [1903, p. 21] Etcheminian on Dugald Brook, Indian River, eastern Cape Breton, Nova Scotia. Lingulella longovalis [Matthew, 1903, p. 77]=Lingulella *Acrothyra signata [Matthew, 1903, p. 77]. triparUis. • Bradorona observator Isevis [Matthew, 1903, p. 77]. Lingulella triparilis [Matthew, 1903, p. 77]. Bradorona spectator [Matthew, 1903, p. 159]. Lingulella (Lingulepis) gregwa? [Matthew, 1903, p. 77]. *Bradorona spectator acuta [Matthew, 1903, p. 77]. Leptobolus? [Matthew, 1903, p. 77]. *Bradoria vigilans obesa [Matthew, 1903, p. 77]. 3441 (references follow species). (For stratigraphic position and association, see p. 134.) (See 13e.) Middle Cambrian: Sandstones of Division E2c of Matthew's [1903, p. 21] Etcheminian, Dugald Brook, Indian River, eastern Cape Breton, Nova Scotia. *Acrothyra signata orta [Matthew, 1903, p. 90]. Bradorona observator tevis [Matthew, 1903, p. 161]. ' 344m (references follow species). (See 13t''.) (For stratigraphic position and association, see p. 134.) Middle Cambrian: Sandy shales of Division Eld of Matthew's [1903, p. 21] Etcheminian on Dugald Brook, Indian River, eastern Cape Breton, Nova Scotia. Bradorona observator [Matthew, 1903, desc. of PI. XII, fig. 15]. Bradorona observator benepuncta [Matthew, 1903, desc. of PI. XII, fig. 16]. *Bradorona perspicator [Matthew, 1903, p. 157]. Bradorona spectator [Matthew, 1903, p. 78]. Bradorona spectator acuta [Matthew, 1903, p. 78]. *Lingulella (Lingulepis) gregwa [Matthew, 1903, p. 78]. *Lingulella (Lingulepis) gregwa robusta [Matthew, 1903, p. 78]. Acrotreta papillata [Matthew, 1903, p. 78]=Acrothyra Acrothyra signata tarda [Matthew, 1903, p. 78]=AcrO' thyra sera. Orthotheca sp. [Matthew, 1903, p. 78]. 344n [Matthew, 1903, p. 33], (For stratigraphic position and association, see p. 134.) Middle Cambrian: Shales in the gorge at the old mill on McCodrum Brook, Mira River, eastern Cape Breton, Nova Scotia. Lingulella (Lingulepis) gregwa. 3440 [Matthew, 1903, p. 134]. (See lOp and lOq.) (For stratigraphic position and association, see p. 134.) Middle Cambrian: Sandstones of Division E2b of Matthew's [1903, p. 21] Etcheminian on Dugald Brook, Indian River, eastern Cape Breton, Nova Scotia. ♦Lingulella (Lingulepis) longinervis. 345 (references follow species). (For stratigraphic position and association, see p. 124.) Middle Cambrian: Green- ish shale in the Paradoxides zone on the Dlouhd, Hora, above the brook of Sbirov, near Skrej, Bohemia. Austria-Hungary. *Lingulella (?) sp. [Pompeckj, 1896b, p. 509]=Lingulella Ptychoparia striata [Pompeckj, 1896b, p. 509]. cf. ferruginea. Ellipsocephalus hoffi [Pompeckj, 1896b, p. 509]. Acrothele bohemica [Pompeckj, 1896b, p. 509]. Conocoryphe sulzeri [Pompeckj, 1896b, p. 511]. Billingsella romingeri [U. S. National Museum and Agraulos spinosus [Pompeckj, 1896b, p. 511]. Pompeckj, 1896b, p. 509]. Agraulos ceticephalus [Pompeckj, 1896b, p. 511]. *0rthi8 sp. [Pompeckj, 1896b, p. 514, fig. 6]=Eoorthis sp. undt. a. 345a [Pompeckj, 1896b, p. 511]. (For stratigraphic position and association, see p. 124.) Middle Cambrian: Shales in the Paradoxides zone on the right bank of the brook of Kardsek, near Tejrovik, Bohemia, Austria- Hungary. Acrothele bohemica. 346b [Pompeckj, 1896b, p. 511]. (For stratigraphic position and association, see p. 124.) the "Bande de Jinec" at Felbabka and Jinec, Bohemia, Austria-Hungary. Acrothele bohemica. Middle Cambrian: In LOCALITIES. 271 3450 (references follow species). (For stratigraphic position and association, see p. 124.) Middle Cambrian: Shales of Etage C at Mleschitz, Bohemia, Austria-Hungary. *Acrothele bohemica [Barrande, 1879b, PI. CII]. Billingsella romingeri (U. S. National Museum). 345d [Pompeckj, 1896b, p. 511]. (For stratigraphic position and association, see p. 124.) Middle Cambrian: Shales of Paradoxides zone. Forester House of Slapy (Buchava quarry), Skrej, Bohemia, Austria-Hungary. *Acrothele quadrilineata. 34Se [Pompeckj, 1896b, p. 514]. (For stratigraphic position and association, see p. 124.) Middle Cambrian: Greenish shale in the Paradoxides zone in the gorge above Luh, near Skrej, Bohemia, Austria-Hungary. *Eoorthis sp. undt. b. 345f (references follow species). (For stratigraphic position and association, see p. 124.) Middle Cambrian: Etage C near Skrej, Bohemia, Austria-Hungary. Nisusia (Jamesella) kuthani (U. S. National Museum). *Billingsella romingeri [Barrande, 1879a, PI. LXII]. 345g [Barrande, 1879a, PI. LXII]. (For stratigraphic position and association, see p. 124.) Middle Cambrian: Etage C at Praschno Augezd, Bohemia, Austria-Hungary. Billingsella romingeri. 345h [Barrande, 1879a, PL LXII]. (For stratigraphic position and association, see p. 124.) Middle Cambrian: Etage C at Slap, Bohemia, Austria-Hungary. Billingsella romingeri. 3451 [U. S. National Museum and Pompeckj, 1896b, p. 514]. (For stratigraphic position and association, see p. 124.) Lower Cambrian: Conglomeratic quartzitic sandstones and graywacke inclusions in the lower conglomerate zone of the Kamenna hurka near Tejfovik, Bohemia, Austria-Hungary. *Nisusia (Jamesella) kuthani. | *Nisusia (Jamesella) perpasta macra. *]SIisu3ia (Jamesella) perpasta. | *Nisusia (Jamesella) perpasta subquadrata. 345] [Pompeckj, 1896b, p. 514]. (For stratigraphic position and association, seep. 124.) Lower Cambrian: Con- glomeratic quartzitic sandstones and grajTvacke inclusions in the lower comglomerate zone of the Kamennd hurka at Gross Lohovic, southwest of Skrej, Bohemia, Austria-Hungary. Nisusia (Jamesella) kuthani. I Nisusia (Jamesella) perpasta macra. Nisusia (Jamesella) perpasta. | Nisusia (Jamesella) perpasta subquadrata. 345k [U. S. National Museum]. (For stratigraphic position and association, see p. 124.) Lower Cambrian: Sand- stones at Slapnicky mlyn, near Skrej, Bohemia, Austria-Hungary. Nisusia (Jamesella) kuthani. Nisusia (Jamesella) perpasta. 345 1 [U. S. National Museum]. (For stratigraphic position and association, see p. 124.) Middle Cambrian: Shales of Etage C at Jinec, Bohemia, Austria-Hungary (Museum Regni Bohemias). Billingsella romingeri. 346 [U. S. National Museum]. Lower Cambrian: Limestone and shale a little south of Emigsville, York County, Pa. Acrothele decipiens. 346a [U. S. National Museum]. Lower Cambrian: Limestone in Landis Valley, Pa. (H. J. Roddy). Micromitra (Paterina) bella. 346b [U. S. National Museum]. Upper Cambrian: Conococheague limestone," 2.75 miles (4.4 km.) south of Mercersburg, Franklin County, Pa. Eoorthis desmopleura. 3460 [U. S. National Museum]. Lower Cambrian: Shale near York, York County, Pa. (A. Wanner). Nisusia festinata. 347 [von Toll, 1899, p. 27]. Lower Cambrian: Near Tschurskaja Station, on Lena River, Siberia. Kutorgina cingulata. 350 [de Vemeuil and Barrande, I860, p. 538]. Middle Cambrian: Red limestone of the Paradoxides zone near Adrados, north of Sabero and Bonar, Cantabrian Mountains, Province of Leon, northwestern Spain. *Acrothele primseva. *Eoorthis primordialis. *Nisusia? vaticina. *Nisusia (Jamesella) pellico. *Brachiopode nouv. gen.=Botsfordia barrandei. Paradoxides pradoanus. Arionellus ceticephalus. Conocephalites sulzeri. Conocephalites sulzeri var. Conocephalites coronatus. Conocephalites ribeiro. Agnostus 2 sp. Leperditia. Capulus cantabricus. Capulus sp. Trochocystites bohemicus?. a Stose, Mercersburg-Chambersburgfolio (No. 170), Geol. Atlas U. S., U. S. Geol. Survey, 1909, p. 6. 272 CAMBRIAN BRACHIOPODA. 350a [Barrois, 1882, p. 186]. Ordovician: Sandstones of the stage of Cabo Busto in the cliffs of Cape Vidio, Pro\-ince of Oviedo, northeastern Spain. *Lingulella heberti. 350b [Barrois, 1882, p. 186]. Ordovician: Sandstones of the stage of Cabo Busto at Los Negros, northeastern Spain. Lingulella heberti. 351 (references follow species). Lower Cambrian: Shales at Monte de Valbom, northeast of Villa Boim, Province of Alemtejo, Portugal. Obolella maculata [Delgado, 1904, p. 364]=Acrothele villaboimensis. *Obolella cf. atlantica [Delgado, 1904, p. 364]=Obolella sp. *Acrothele villaboimensis [Delgado, 1904, p. 365]. *Delgadella lusitanica [Delgado, 1904, p. 365]. Lingulepis acuminata meeki [Delgado, 1904, p. 366] =Lingulella delgadoi. *Lingulella granvillensis [Delgado, 1904, p. 367]=Lingu- lella delgadoi. *Lingulella ferruginea [Delgado, 1904, p. 368]= Lingulella delgadoi. *Lingulella cf. linguloides [Delgado, 1904, p. 369]=Liii_ gulella delgadoi. *Paradoxides choffati [Delgado, 1904, p. 319]. Paradoxides sp. aff. abenacus [Delgado, 1904, p. 322]. Paradoxides sp. n. aff. spinosus [Delgado, 1904, p. 323]. Paradoxides costae [Delgado, 1904, p. 323], Paradoxides sp. aff. tessini [Delgado, 1904, p. 324]. Olenopsis sp. Olenellus? (hypostoma). Hicksia elvensis [Delgado, 1904, p. 333]. Hicksia sphaerica [Delgado, 1904, p. 335]. Hicksia transtaganensis [Delgado, 1904, p. 337]. Hicksia walcotti [Delgado, 1904, p. 338]. Hicksia castroi [Delgado, 1904, p. 340]. Hicksia hughesi [Delgado, 1904, p. 341]. These species may not be from the same bed or even from the same locality. 353 [Roemer, 1849, p. 420]. Upper Cambrian: Limestones on San Saba River, San Saba County, Tex. *Lingulella acutangula. No other associated species (Roemer). 353a [Shumard, 1860, p. 627]. Upper Cambrian: Sandstones near the head of Morgans Creek, Burnet County, Tex. *Billingsella coloradoensis. 353b [U. S. National Museum]. Upper Cambrian: Sandstone just beneath the Ophikta beds, south end of the Franklin Range, El Paso County, Tex. Lingulella (Lingulepis) acuminata. 353c [U. S. National Museum]. Upper Cambrian: Heavy dark ferruginous sandstone in Llano County, Tex. (exact locality unknoAvn). Lingulella acutangula. 354 (references follow species). Middle? Cambrian: In yellowish-brown slates not far from the buildings of Canal Grande, island of Sardinia, Italy. Hicksia barroisi [Delgado, 1904, p. 342]. Hicksia delwalquei [Delgado, 1904, p. 343]. Hicksia minuta [Delgado, 1904, p. 344]. Metadoxides bornemanni [Delgado, 1904, p. 345]. Olenellus (?) macphersoni [Delgado, 1904, p. 347]. Microdiscus caudatus [Delgado, 1904, p. 349]. Microdiscus subcaudatus [Delgado, 1904, p. 350]. Microdiscus wenceslasi [Delgado, 1904, p. 350]. Microdiscus souzai [Delgado, 1904, p. 351]. Microdiscus woodward! [Delgado, 1904, p. 353]. Crustacean (?) (telson). Crustacean sp. Hyolithes lusitanicus [Delgado, 1904, p. 355]. Hyolithes cf. billingsi [Delgado, 1904, p. 356]. Hyolithes sp. aff. communis [Delgado, 1904, p. 356]. Pteropoda sp. Posidonomya malladai [Delgado, 1904, p. 357]. Fordilla troyensis [Delgado, 1904, p. 358]. Modiolopsis zitteli [Delgado, 1904, p. 359]. Modiolopsis bocagei [Delgado, 1904, p. 360]. Synek (?) cambrensis [Delgado, 1904, p. 360]. Davidia dollfusi [Delgado, 1904, p. 361]. Davidia cotteri [Delgado, 1904, p. 362]. Davidia egozcuei [Delgado, 1904, p. 362]. Ctenodonta geikiei [Delgado, 1904, p. 363]. Bivalve sp. *Luigula attenuata [Bornemann, 1891, p. 438]= Lingulella bornemanni. *Kutorgina cingulata [Bornemann, 1891, p. 440]=Kutor- gina sardiniaensis. Olenopsis [Bornemann, 1891, p. 440]. Metadoxides [Bornemann, 1891, p. 440]. Lingulella sp. undt. (U. S. National Museum). These species may not be from the same bed or even from the same exact locality. 354a (references follow species"). Middle? Cambrian: In grayish- white quartzitic sandstone in the valley of Gutturu Sartu, island of Sardinia, Italy. Olenopsis zoppi [Bornemann, 1891, p. 459]. Metadoxides armatus [Bornemann, 1891, p. 465]. Metadoxides bornemanni [Bornemann, 1891, p. 466]. Metadoxides torosus [Bornemann, 1891, p. 462]. Etc. *Lingula hawkei [Bornemann, 1891, p. 439]=Mickwitzia sp. undt. Lingula attenuata [Bornemann, 1891, p. 438]=Liiigulella bornemanni. Olenopsis bornemanni [Bornemann, 1891, p. 458]. These species may not be from the same bed or even from the same exact locality. LOCALITIES. 273 354b (references follow species). (See 354c.) Middle? Cambrian: In yellowish sandstone with Archseocyathus at Punta Pintau and elsewhere, island of Sardinia, Italy. Carinaropsis patelloides [Bomemann, 1891, p. 441]. Capulus minutus [Bomemann, 1891, p. 441]. Olenopsis bornemanni [Bomemann, 1891, p. 458]. Etc. Lingula attenuata [Bomemann, 1891, p. 438]=Lingulella bornemanni. Kntorgina cingulata [Bomemann, 1891, p. 440]=Kutor- gina sardiniaensis. These species may not be from the same bed or even from the same exact locality. 354c (references follow species). (See 354b.) Middle? Cambrian: Yellow friable sandstone at Punta Pintau (Canal Grande), island of Sardinia, Italy. 438]=Obolus? Paradoxides asper [Bomemann, 1891, p. 468]. Etc. *Lingula petalon [Bomemann, 1891, p. meneghinii. Metadoxides arenarius [Bomemann, 1891, p. 467]. These species may not be from the same bed or even from the same exact locality. 354d [Bomemann, 1891, p. 438]. Middle? Cambrian: Yellow friable sandstone at Gruguetta, island of Sardinia, Italy. Lingula petalon=Obolus? meneghinii. 354e (references follow species). Middle ? Cambrian: Shale at Porto Canal Grande, island of Sardinia, Italy. Olenopsis bornemanni [Bomemann, 1891, p. 458]. Olenopsis longispinatus [Bomemann, 1891, p. 459]. Olenopsis zoppi [Bomemann, 1891, p. 459]. Metadoxides armatus [Bomemann, 1891, p. 465]. Etc. Obolella sp. [Bomemann, 1891, p. 440]=Obolus? mene- ghinii. Lingula roualti [Bomemann, 1891, p. 439]=Kutorgina sar- diniaensis. Kutorgiaa sardiniaensis (LT. S. National Museum). Bellerophon? priscus [Bomemann, 1891, p. 441]. These species may not be from the same bed or even from the same exact locality. 354f [Bomemann, 1891, p. 439; U. S. National Museum]. Middle ? Cambrian: Reddish-yellow sandstone near the houses of Canal Grande, on the road to Punta Pintau, island of Sardinia, Italy. *Obolella crassa=Obolus? zoppi. 355 [U. S. National Museum]. Middle Cambrian: Sandstones on Red Canyon Creek, southwest side of Black Hills, South Dakota. Some of the specimens are labeled Redwater Canyon, and this locality appears in Whitfield [1882, p. 340]. Dicellomus nanus. Dicellomus politus. Middle Cambrian: Shales in Bear Gulch Valley, Black Hills, South Dakota. Middle Cambrian: Sandstone in the Deadwood formation on Castle Creek, on the Middle Cambrian: Sandstone on French Creek, Black Hills, South Dakota. Middle Cambrian: Sandstone in the Black Hills, South Dakota. *Lingulella cuneola. *Lingulella perattenuata. Lingulella (Lingulepis) acuminata. 355a [U. S. National Museum]. Lingulella similis. 355b [U. S. National Museum]. west side of the Black Hills, South Dakota. Lingulella (Lingulepis) acuminata. Dicellomus pectenoides. 355c [■^Tiitfield, 1875, p. 103]. *Dicellomus pectenoides. 355d [U. S. National Museum] Lingulella (Lingulepis) acuminata. *Dicellomus nanus. 355e [U. S. National Museum]. Middle Cambrian: Sandstone in the central part of the Black Hills, South Dakota. Dicellomus politus. 355f.'i Middle Cambrian: Sandstones near Deadwood, Black Hills, South Dakota. Lingulella perattenuata. 357 [Waagen, 1885, p. 769]. Middle Cambrian: Limestone in the "Neobolus beds" of the Khussak group, above the salt mine at Kiura (Khewra), Salt Range, India. *Lingulella kim-ensis. 357a (references follow species). Middle Cambrian: Lower portion of the "Neobolus beds" of the Khussak group, in purplish-colored, fine-grained, micaceous sandstone, at Jutdna, Salt Range, India. *Neobolus warthi [Waagen, 1885, p. 759]. Neobolus wynnei [\\^aagen 1885, p. 760] . . ^Neobolus warthi. Davidsonella Imguloides {Waagen, 188o, p. 765}. Davidsonella squama [Waagen, 1885, p. 767] *Discinolepis granulata [Waagen, 1885, p. 751]. n The authority tor the citation of this locality was mislaid and could not be traced in time for insertion in this volume. 62667°— VOL 51, pt 1—12 18 274 CAJk/IBKIAN BRACHIOPODA. 357b [Waagen, 1885, p. 759], Middle Cambrian: Lower portion of the "Neoholus beds" of the Khussak group, in purplish-colored, fine-grained, micaceous sandstone, at Chfl Hill, Salt Range, India. Neobolus warthi. 357c (references follow species). Middle Cambrian: Lower portion of the "Neoholus beds" of the Khussak group, in purplish-colored, fine-grained, micaceous sandstone, near the fresh-water springs in a gorge above the salt mines at Kiura (Khewra), Salt Range, India. *Schizopholis rugosa [Waagen, 1885, p. 754]. Neobolus warthi [Waagen, 1885, p. 759] 1 Neobolus wjTinei [Waagen, 1885, p. 760] i=Neobolu3 warthi. Davidsonella linguloides [Waagen, 1885, p. 765].. J Discinolepis granulata [Waagen, 1885, p. 751]. 357d [T^'aagen, 1891, p. 104]. Middle Cambrian: "Concretionary shales of the Khussak group" at several locali- ties between Ch61 Hill and Kiura (Khewra), eastern part of the Salt Range, India. *Wynnia warthi. I Conocephalites warthi. Hyolithes wynnei. | Trilobites gen. and sp. undt. 358 [U. S. National Museum]. Middle Cambrian:. Argillaceous shale 50 feet (15.2 m.) above the Coronado quartzite [Lindgren, 1905, p. 3], west side of Chase Creek Canyon, 1.5 miles (2.4 km.) east^northeast of Morenci, Clif- ton quadrangle (U. S. G. S.), Graham County, Ariz. Lingulella lineolata. 358a [U. S. National Museum]. Upper? Cambrian: Siliceous limestone on Ash Creek, in Pinal County, Ariz. Lingulella pogonipensis?. Dicellomus politus. 358b [U. S. National Museum]. Middle Cambrian: Limestone on the southwest side of Escabrosa Ridge, 4.5 nules (7.2 km.) west-southwest of Bisbee, Ariz. (F. L. Ransome, 1902). Obolus zetus. 360 [U. S. National Museum]. Lower Ordovician: Red siliceous limestone near Colorado Springs, El Paso County, Colo. Lingulella desiderata. Schizambon manitouensis. Eoorthis desmopleura. 360a [U. S. National Museum], Lower Ordovician: Red siliceous limestone on west side of Trout Creek, below Bergen Park, 7 miles (11.2 km.) north-northwest of Manitou, El Paso County, Colo. Obolus matinalis. I Eoorthis desmopleura. Lingulella desiderata. | Eoorthis wichitaensis. 360b [U. S. National Museum]. Lower Ordovician: Red siliceous limestone on Cement Creek, 3 miles (4.8 km.) north of Hot Springs, Ouray County, Colo. Lingulella desiderata. 360c [U. S. National Museum], Lower Ordovician: Red siliceous limestone about 10 miles (16.1 km.) southeast of Crested Butte, Elk Range, Colo. Lingulella desiderata. 360d [U.S. National Museum]. Middle Cambrian: Siliceous limestones near Pike "View, north of Colorado Springs, El Paso County, Colo. Lingulella similis. 360f [U. S. National Museum]. Lower Ordovician: Siliceous limestone at Glen Eyre, Queens Canyon, northeast of Manitou, El Paso County, Colo. *Eoorthis desmopleura. 360g [U. S. National Museum records]. Upper Cambrian: Shaly sandstone on Trout Creek, 1 mile (1.6 km.) below Manitou Park, El Paso County, Colo. Lingulella (Lingulepis) acuminata. 360h [U. S. National Museum], (100 feet above 360i; see locality 3g.) Upper Cambrian: Sandy shales about 200 feet (61 m.) above the base of the section at Glenwood Springs, Garfield Coimty, Colo. (T. W. Stanton, 1889). Obolus msera. 360i [U. S. National Museum]. (100 feet below 360h; see locality 3g.) Upper Cambrian: Sandstones about 100 feet (30 m.) above the base of the section at Glenwood Springs, Garfield County, Colo. (T. W. Stanton, 1889). Obolus msera. LOCALITIES. 275 361 [U. S. National Museum]. (For stratigraphic position and association, see p. 147.) Upper Cambrian: Shaly limestone in suburb of Attalla, Etowah County, Ala. (M. R. Campbell). Lingulella desiderata. Acrotreta kutorgai. 362 [U. S. National Museum], (For stratigraphic position and association, see p. 147.) Fpper Cambrian: Shales in the Oothkalooga Valley, Bartow County, Ga. Lingulella desiderata. 362a [U. S. National Museum]. (For stratigraphic position and association, see p. 147.) Middle Cambrian: Sandy shale a short distance west of Cave Spring, Floyd County, Ga. Lingulella similis. 364 [Sardeson, 1896, p. 95]. Upper Cambrian: St. Lawrence formation in both Wisconsin and Minnesota. Lingulella mosia. 364a [Sardeson, 1896, p. 9.5], Lower Ordovician: "Oneota dolomite" along St. Croix River in both Wisconsin and Minnesota. Lingulella mosia, 366 [Davidson, 1866, p. 57], (For stratigraphic position and association, see p. 135.) Upper Cambrian: "Whitesand Bay, near St. Davids Head, Pembrokeshire, South Wales. Lingulella davisi. 366a [U. S. National Museum]. (For stratigraphic position and association, see p. 135.) Upper Cambrian: Upper portion of Middle Lingula flags 6 miles (9.6 km.) east of Ffestiniog, Merionethshire, North Wales. Lingulella davisi. 366b [U. S. National Museum]. (For stratigraphic position and association, see p. 136.) Middle Cambrian: Red shales at the base of the Harlech grits at Porthclais Harbor, south of St. Davids, South Wales. Lingulella ferruginea. 366c [Salter and Etheridge, 1881, p. 538]. (See 318i.) (For stratigraphic position and association, see p. 136.) Middle? Cambrian: "Caerfai group" at Caerfai, Nuns Hill, and Porthclais Harbor, south of St. Davids, South Wales. *Lingulella primseva. 366d [Davidson, 1866, p. 57]. (For stratigraphic position and association, see p. 135.) Upper Cambrian: Lower Lingula flags at Carnedd Filiast, Bangor, Carnarvonshire, North Wales. Lingulella davisi. 366e [Davidson, 1866, p. 57]. (For stratigraphic position and association, see p. 135.) Upper Cambrian: Lower Lingula flags at Marchillyn-mawr, Llanberis, Carnarvonshire, North Wales. Lingulella davisi. 366f [Davidson, 1866, p. 57]. (For stratigraphic position and association, see p. 135.) Upper Cambrian: Lower Lingula flags at Ffestiniog, Merionethshire, North Wales. Lingulella davisi. 366g [Davidson, 1866, p. 57]. (For stratigraphic position and association, see p. 135,) Upper Cambrian: Lower Lingula flags at Dolgelly, Merionethshire, North Wales. Lingulella davisi. 366h, [Davidson, 1866, p. 57]. (For stratigraphic position and association, see p. 135.) Upper Cambrian: Lower Lingula flags at Pen-y-Bryn, 5 miles (8 km,) north of Dolgelly, Merionethshire, North Wales. Lingulella davisi. 3661 [Davidson, 1866, p. 57]. (For stratigraphic position and association, see p. 135.) Upper Cambrian: Lower Lingula flags at Lljoi Dywarchen, Merionethshire, North Wales. Lingulella davisi. 366j [Davidson, 1866, p. 57.] (For stratigraphic position and association, see p. 135,) Upper Cambrian: Lower Lingula flags at Pont Nant-y-Lladron, on the Bala Road from Ffestiniog, Merionethshire, North Wales. Lingulella davisi. 366k [Davidson, 1866, p. 57]. (For stratigraphic position and association, see p. 135.) Upper Cambrian: Lower Lingula flags at Penmorfa, Merionethshire, North Wales. Lingulella davisi. 3661 [Davidson, 1866, p. 57). (For stratigraphic position and association, see p. 135). Upper Cambrian: Lower Lingula flags at Tremadoc, Merionethshire, North Wales. Lingulella davisi. 276 CAJMBRIAN BEACHIOPODA. seem [Davidson, 1866, p. 57]. (For stratigraphic position and association, see p. 135.) Upper CamDrian: Lower Lingula flags near Nant-y-groes, west of Bala, Merionethshire, North Wales. Lingulella da^dsi. 366n [U. S. National Museum]. (For stratigraphic position and association, see p. 135.) Upper Cambrian: Lower Lingula flags at Portmadoc, Merionethshire, North Wales. Lingulella davisi. 3660 [McCoy, 1854, p. 254]. (For stratigraphic position and association, see p. 135.) Upper Cambrian: "Bala schists" at Bryn Melyn, near Bala, Merionethshire, North Wales. Lingulella davisi. 366p [Davidson, 1866, p. 57]. (For stratigraphic position and association, see p. 135.) Upper Cambrian: Upper Tremadoc beds at Deudraeth, Merionethshire, North Wales. Lingulella da^dsi. 366c( (references follow species). (For stratigraphic position and association, see p. 135.) Upper Cambrian: Upper Tremadoc beds at Garth, opposite Portmadoc, Merionethshire, North Wales. Lingulella da\Tsi [Davidson, 1866, p. 57]. Lingulella lepis [Davidson, 1866, p. 54]. 366r [U. S. National Museum]. (For stratigraphic position and association, see p. 135.) Upper Cambrian: Shales 2 miles (3.2 km.) north of Builth, Brecknockshire, South Wales. Lingulella davisi. 366s [U. S. National Museum]. (See 366a.) (For stratigraphic position and association, see p. 135.) Upper Cambrian: Upper Lingula flags 5 miles (8 km.) east of Ffestiniog, Merionethshire, North Wales. Orusia lenticularis. 367 [U. S. National Museum]. Lower Cambrian; Conglomerate and limestone, Troy, Rensselaer County, N. Y. *Lingulella schucherti. Microdiscus schucherti. Protypus hitchcocki (^Tiitfield). These species may be from widely different localities. 367a [U. S. National Museum]. (See 38.) Lower Cambrian: Limestone about a third of a mile (0.5 km.) south of John Hulett's farmhouse, 3 miles (4.8 km.) west of South Granville, and 4.5 miles (7.2 km.) southwest of Granville, Fort Ann quadrangle (U. S. G. S.), Washington County, N. Y. Billingsella salemensis. 367b [U. S. National Museum]. Lower Cambrian: Sandstone at Lansingburg, north of Troy, Cohoes quadrangle (U. S. G. S.), Rensselaer County, N. Y. Billingsella salemensis??. Scenella sp. 367c [U. S. National Museum]. Ordovician: Beekmantown limestone. Division A, quarry near the northwest suburbs of Ticonderoga, Essex County, N. Y. *Lingulella (Lingulepis) acuminata sequens. 367d (references follow species). Middle Cambrian: Limestones near Stissing, Dutchess County, N. Y. *Micromitra (Paterina) stissingensis [Dwight, 1889, p. 145]. I *Leperditia ebenina [Dwight, 1889, p. 144]. Hyolithes billingsi? [Dwight, 1889, p. 143]. | *01enoides stis.singensis [Dwight, 1889, p. 147]. 367e [Dwight, 1886, p. 205]. Upper Cambrian: Shaly limestones 850 feet (259.1 m.) southerly from the southwest corner of the dri\dng park and 2,200 feet (670.6 m.) west of the road leading southerly from the same, about 1 mile (1.6 km.) southwest of Vassar College, near Poughkeepsie, Dutchess County, N. Y. Lingulella (Lingulepis) acuminata. 367f [U. S. National Museum]. Upper Cambrian: Sandstone at French Creek, 1 mile (1.6 km.) east of Keeseville, Essex County, N. Y. Lingulella prima. 367g [U. S. National Museum]. Upper Cambrian: Sandstone in the bed of the brook in the suburbs of Port Henry, Essex County, N. Y. Lingulella prima. 367h [U. S. National Museum]. Upper Cambrian: Sandstone at Rosses Bridge, 4 miles (6.4 km.) west of Essex village, Essex County, N. Y. Lingulella prima. Paradoxides bohemicus [Gurich, 1896, p. 17]. Agnostus fallax [Gurich, 1896, p. 17]. Agnostus gibbus [Gurich, 1896, p. 17], Liostracus linnarssoni [Gmich, 1896, p. 17]. LOCALITIES. 277 3671 [Hall, 1847, p. 290]. Lower Cambrian: Shales near Troy, Rensselaer County, N. Y. *Botsfordia cselata. 367j [U. S. National Museum], (See 108.) Upper Cambrian: Sandstones 3 miles (4.8 km.) south of Pough- keepsie, Dutchess County, N. Y. Lingulella (Lingulepis) acuminata. 367k [U. S. National Museum]. (See 109.) Upper Cambrian: Sandstone at Deweys Bridge, Washington County N.Y. Lingulella (Lingulepis) acuminata. 3671 [U. S. National Museum]. Cambrian: Shales 0.75 mile (1.2 km.) southwest of Hillsdale, Fort Ann quad- rangle (U. S. G. S.), Washington County, N. Y. (L. M. Prindle, 1895). Obolus sp. 368 (references follow species). Middle Cambrian: Quartzitic sandstone in the Pepper Mountains, near Sandomierz on the Vistula, Russian Poland. Obolus apollinis (U. S. National Museum). *Lingulella siemiradzkii (U. S. National Museum). Lingula cf. crassa [Gurich, 1896, p. 214]=Lingulella siemiradzkii. Paradoxides cf. tessini [Gurich, 1896, p. 17]. 368a [Siemiradzki, 1886, p. 672]. Gray sandstone of unknown stratigraphic position or age in the Polnischen Mittelgebirge, north of Sandomierz on the Vistula, Russian Poland. Obolus "(Mickwitzella) siluricus. 369 [U. S. National Museum]. (For sti-atigraphic position and association, see p. 137.) Upper Cambrian: Sand- stone in the Elvins formation in the eastern limits of the town of Flat River, St. Francois County, Mo. *Obolus ismene. i Linnarssonella girtyi. Lingulella texana. | Eoorthis indianola. 369a [U. S. National Museum]. (For stratigraphic position and association, see p. 137.) Middle Cambrian: Lime- stone in or just beneath the "Edgewise beds "near Elvins, 6 miles (9.6 km.) south of Bonneterre, St. Francois County, Mo. Eoorthis wichitaensis. 369b [U. S. National Museum]. Upper Cambrian: Limestone neai- Potosi, Washington County, Mo. Eoorthis indianola. 369c [U. S. National Museum]. (For stratigraphic position and association, see p. 137. ) Upper Cambrian : Dolomite above the "Edgewise beds" in a railroad cut 0.5 mile (0.8 km.) southwest of Elvins, 6 miles (9.6 km.) south of Bonneterre, St. Francois County, Mo. (E. 0. Ulrich). Billingsella major?. 369d [U. S. National Museum]. (For stratigraphic position and association, see p. 137.) Upper Cambrian: Upper portion of the Elvins formation 2.5 to 3 miles (4 to 4,8 km.) north of Caledonia, Washington County, Mo. Billingsella coloradoensis. 369e [U. S. National Museum]. (For stratigraphic position and association, see p. 137.) Upper Cambrian: Sand- • stone on Big River, near Montana, Iron County, Mo. Billingsella coloradoensis. 369f [Walcott, 1891b, p. 341]. (For stratigraphic position and association, see p. 137.) Middle Cambrian: Lime- stone at Fredericktown, Madison County, Mo. Obolus lamborni. 369g [LT. S. National Museum]. (For stratigraphic position and association, see p. 137.) Middle Cambrian: Shales at Bonneterre, St. Francois County, Mo. Lingulella desiderata. 369h [U. S. National Museum]. (For stratigraphic position and association, see p. 137.) Middle Cambrian: Shale at Mine Lamotte, Madison County, Mo. (C. D. Walcott and F. B. Meek). Obolus lamborni. 372 [U, S. National Museum]. (See 8d.) (For stratigraphic position and association, see p. 131.) Upper Cambrian: Shale at Upper Leitches Creek, eastern Cape Breton, Nova Scotia. Lingulella concinna. 372a [U. S. National Museum]. (See 10m.) (For stratigraphic position and association, see p. 131.) Upper Cam- brian: Shale 2 miles (3,2 km.) south of the Boisdale road from Upper Leitches Creek, eastern Cape Breton, Nova Scotia. Lingulella concinna. 278 CAIMBRIAN BRACHIOPODA. 372b [U. S. National Museum]. (See 3p.) (For stratigraphic position and association, see p. 131.) Upper Cam- brian: Shale in ravine 0.5 mile (0.8 km.) north of McMullins, on the crossroad to Boisdale railroad station, eastern Cape Breton, Nova Scotia. Lingulella concinna. 372c [U. S. National Museum]. (See So.) (For stratigraphic position and association, see p. 131.) Upper Cambrian: Shale in ravine east of the railroad, just south of Barachois post oflBce, eastern Cape Breton, Nova Scotia. Lingulella concinna. 372d [U. S. National Museum]. (For stratigraphic position and association, see p. 131.) Upper Cambrian: Shale on McAdam shore. East Baj', east of Bras d'Or Lake, eastern Cape Breton, Nova Scotia. Lingulella concinna. 372e [Matthew, 1903, p. 50]. (For stratigraphic position and association, see p. 131.) Upper Cambrian: Shales on McMullins Brook, near McLeod Brook (=Bai-achois River), eastern Cape Breton, Nova Scotia, Canada. Monobolina refulgens. Schizambon priscus. 372f [U. S. National Museum]. (For stratigraphic position and association, see p. 134.) Middle Cambrian: Shales on Dugald Brook, Indian River, eastern Cape Breton, Nova Scotia. Lingulella (Lingulepis) longinervis. 374 [U. S. National Museum]. (For stratigraphic position and association, see p. 147.) Middle Cambrian : In the suburbs of and 4 and 11 miles (6.4 and 17.7 km.) north-northeast of Knoxville, Knox County, Tenn. Lingulella similis. 374a [U. S. National Museum]. (For stratigraphic position and association, see p. 147.) Middle Cambrian: Lime- stone 2 miles (3.2 km.) south of Coal Creek, Anderson County, Tenn. i Dicellomus appalachia. 374b [U. S. National Museum]. (For stratigraphic position and association, see p. 147.) Middle Cambrian : Shale 1.25 miles (2 km.) from Rogersville, on the road to Powell, near the line between the Morristown and Greene- ville quadrangles (U. S. G. S.), Hawkins County, Tenn. Dicellomus appalachia. 374c [U. S. National Museum]. (For stratigraphic position and association, see p. 147.) Middle Cambrian : Sandy shale (Nolichucky?) [Campbell, 1899, p. 3] 8 miles (12.8 km.) northeast of Shipleys, near the line between the Roan Mountain and Bristol quadrangles (U. S. G. S.), Sullivan County, Tenn. Dicellomus appalachia. 374d [U. S. National Museum], (For stratigraphic position and association, seep. 147.) Middle Cambrian: Shale 2 miles (3.2 km.) north of Rotherwood, Hawkins County, Tenn. (Cooper Curtice). Lingulella (Lingulepis) acuminata. 374e [U. S. National Museum]. (For stratigraphic position and association, see p. 147.) Middle Cambrian: Shales collected near the state line, 2.25 miles (3.6 km.) north of Peltier, Estillville quadrangle (U. S. G. S.), Sulli- van County, Tenn. (M. R. Campbell). Obolus willisi. 386 [Gagel, 1890, p. 34]. Passage beds between the Upper Cambrian and the Ordovician: Drift blocks of Cerato- pyge limestone near Belschwitz, East Prussia, Germany. Eoorthis daunus. 386a [Gagel, 1890, p. 34]. Passage beds between the Upper Cambrian and the Ordovician: Drift blocks of "Glau- conite limestone" near Prussian Holland, 90 miles (145 km.) south-southwest of Konigsberg, East Prussia, Germany. Orthis christianise=Eoorthi3 daunus?. 386b (references follow species). Passage beds between the Upper Cambrian and Ordovician: Drift blocks of "Glauconite limestone" near Wehlau, 30 miles (48.3 km.) east of Konigsberg, East Prussia, Germany. Obolus (Acritis) antiquissimus [Gagel, 1890, p. 22]. 1 Orthis christianiK [Gagel, 1890, p. 34]=Eoorthis daunus?.P«^^ "P®"*^^ "^^^ °'^™'' '" different blocks of limestone. 386c [Roemer, 1885, p. 23 (270)]. Upper Cambrian: Drift bowlder found near Lyck, East Prussia, Germany. Obolus apollinis. 386d [Roemer, 1885, p. 23 (270)]. Upper Cambrian: Drift bowlder found near Danzig, West Prussia, Germany. Obolus apollinis. 386e [Roemer, 1885, p. 33 (280)]. LTpper Cambrian: Drift bowlders of gray bituminous limestone between Vistula and Elbe rivers, in Schleswig-Holstein and Mecklenburg-Schwerin, Germany. Orusia lenticularis. Parabolina spinulosa. LOCALITIES. 279 386f [Roemer, 1885, p. 34 (281)]. Upper Cambrian: Drift bowlders of gray bituminous limestone near Wismar, Mecklenburg-Schwerin, Germany. Orusia lenticularis. 386g [Roemer, 1885, p. 34 (281)]. Upper Cambrian: Drift bowlders of gray bituminous limestone near Rostock, Mecklenburg-Schwerin, Germany. Orusia lenticularis. 38611 [Roemer, 1885, p. 34 (281)]. Upper Cambrian: Drift bowlders of gray bituminous limestone near Meseritz, Province of Posen, Germany. Orusia lenticularis. 3861 (references follow species). (For stratigraphic position and association, see p. 143.) Ordovician: Drift bowlder of EcMnosphserites limestone near Wehlau, 30 miles (48.3 km.) east of Konigsberg, East Prussia, Germany. Siphonotreta unguiculata [Gagel, 1890, p. 23]. Siphonotreta verrucosa [Gagel, 1890, p. 22]. 386j [Gagel, 1890, p. 23]. (For stratigraphic position and association, see p. 143.) Ordovician: Drift bowlder of EcMnosphserites limestone at Belschwitz, East Prussia, Germany. Siphonotreta unguiculata. 386k [Gagel, 1890, p. 22]. (For stratigraphic position and association, see p. 143.) Ordovician: Drift bowlder of Echinosphseriles limestone near Wormditt, East Prussia, Germany. Siphonotreta unguiculata. Siphonotreta verrucosa. 3861 [Gagel, 1890, p. 22]. (For stratigraphic position and association, seep. 143.) Ordovician: Drift bowlder of EcMnosphserites limestone near Marienwerder, West Prussia, Germany. Siphonotreta unguiculata. Siphonotreta verrucosa. 389 [Kayser, 1876, p. 8]. Upper Cambrian: Sandstone at Salta, Province of Salta, Argentina, South America. *Eoorthis saltensis. 389a [Kayser, 1876, p. 8]. Upper Cambrian: Sandstone at Nevado de Castillo, Province of Salta, Argentina, South America. Eoorthis saltensis. 389b (references follow species). Upper Cambrian America. Orusia lenticularis [Kayser, 1876, p. 9]. Eoorthis saltensis [Kayser, 1876, p. 8]. *Obolus sp. undt. e [Kayser, 1876, p. 9]. Hyolithes sp. undt. [Kayser, 1876, p. 8]. Sandstone at Tilcuya, Province of Jujuy, Argentina, South Agnostus tilcuyensis [Kayser, 1876, p. 5]. Olenus argentinus [Kayser, 1876, p. 6]. Arionellus lorenzi [Kayser, 1876, p. 7]. Arionellus hyeronimi [Kayser, 1876, p. 7], 389c [Kayser, 1897, p. 280]. Upper Cambrian: Conglomeratic sandstone at Ojo de Agua, Province of Santiago del Est, about 70 miles (112 km.) north of Cordova, Argentina, South America. *Eoorthis saltensis. 389d. (references follow species). Upper Cambrian: At Iruya, Province of Salta, Argentina, South America. Lingulella davisi [Kayser, 1897, p. 280]. Lingulella feiTUginea [Kayser, 1897, p. 280]. Eoorthis saltensis [Kayser, 1897, p. 280]. Agnostus iruyensis [Kayser, 1897, p. 279]. Liostracus ulrichi [Kayser, 1897, p. 277]. Liostracus steinmanni [Kayser, 1897, p. 277]. 390 [U. S. National Museum]. (For stratigraphic position and association, see p. 144.) Passage beds between the Upper Cambrian and the Ordovician: Boundary stratum between the Orthoceras limestone and Cera- fopyge limestone [Moberg and Segerberg, 1906, p. 69] at Alunbruk (alum works), southern part of Oeland Island, Sweden. *EoortSiis tullbergi. 390a [Moberg, 1892b, p. 112]. (For stratigraphic position and association, see p. 146.) Lower Cambrian : Drift blocks of glauconitic quartzitic sandstone at several points near Stora Rbr, Kalmar sheet (Geol. Survey Sweden), Oeland Island, Sweden. *Micromitra (Paterina) undosa. Discinella. 390b (references foUow species). (For stratigraphic position and association, see p. 145.) Upper Cambrian: Lime- stone of the Shumardia zone (zone 3) at Fogelsang, 5 miles (8 km.) east of Lund, Pro"\dnce of Malmohus, Sweden. Eoorthis wimani [Moberg and Segerberg, 1906, p. 71]. Trochus atavus [Moberg and Segerberg, 1906, desc. of PL III]. Shumardia celandica [Moberg and Segerberg, 1906, desc. of PL IV]. Shumardia dicksoni [Moberg and Segerberg, 1906, desc. of PL IV]. Symphysurus angustatus [Moberg and Segerberg, 1906, desc. of PL V]. Orometopus elatifrons? [Moberg and Segerberg, 1906, desc. of PL VII]. 280 CAllBEIAN BRACHIOPODA. Cyrtometopus primigenus [Moberg and Segerberg, 1906, desc. of PI. VII]. 390c (references follow species). (For stratigraphic position and association, see p. 145.) Upper Cambrian: Ceratopyge slate (zone 3) at Wentlinge, Oeland Island, Sweden. Eoorthis wimani [Moberg and Segerberg, 1906, p. 70]. Beyrichia nanella [Moberg and Segerberg, 1906, desc. of PI. III]. Shumai'dia oelandica [Moberg and Segerberg, 1906, desc. of PI. IV]. 390d [Moberg, 1892b, p. 112]. (For stratigraphic position and association, see p. 146.) Lower Cambrian: Drift blocks of glauconitic quartzitic sandstone north of Rohiilla, Kalmar sheet (Geol. Survey Sweden), Oeland Island, Sweden. Micromitra (Paterina) undosa. | Discinella. 390e [Moberg and Segerberg, 1906, pp. 71 and 109]. (For stratigraphic position and associaticn, see p. 144.) Pas- sage beds between the Upper Cambrian and the Ordovician: Apatocephalus zone of the Ceratopyge suite at Ottenby, Oeland Island, Sweden. Eostrophomena elegantula. 390f (U. S. National Museum). (For stratigraphic position and association, see p. 144.) Passage beds between the Upper Cambrian and the Ordovician: Shales between the "lower graptolite slate" and the Ceratopyge limestone at Mossebo, on Hunneberg, western boundary of the Province of Skaraborg, Sweden. *Protorthis'? hunnebergensis. 390g [Moberg and Segerberg, 1906, p. 64, and U. S. National Museum]. (See 3091.) (For stratigraphic position and association, see p. 14b.) Upper Cambrian: Limestone in the Dictyograptus slate at Sandby, 6 miles (9.6 km.) east-northeast of Lund, Province of Malmohus, Sweden. Obolus (Broggeria) salteri. 39011 [Moberg, 1892b, p. 112]. (For stratigraphic position and association, see p. 146.) Lower Cambrian: Drift blocks of glauconitic quartzitic sandstone on Nordmannaskar Island, Kalmar sheet (Geol. Survey Sweden), Sweden. Micromitra (Paterina) undosa. Discinella. 3901 (U. S. National Museum). (SeeSlOd.) (For stratigraphic position and association, seep. 145.) Upper Cam- brian: Limestone band in the Ceratopyge slate at Borgholm, Oeland Island, Sweden. Obolus (Broggeria) salteri. 390j (references follow species). (For stratigraphic position and association, seep. 146.) Lower Cambrian : Eophyton sandstone at Lugnas, 8 miles (12 km.) south-southwest of Mariestad, Province of Skaraborg, Sweden. *Hyolithes Isevigatus [Linnarsson, 1871, p. 9], *Mickwitzia monilifera [U. S. National Museum and Linnarsson, 1869a, p. 344]. *Mickwitzia pretiosa (U. S. National Museum). Arenicolites spiralis [Linnarsson, 1869b, p. 398]. Frsena tenella [Linnarsson, 1871, p. 11], *Agelacrinus? lindstromi [Linnarsson, 1871, p. 1]. Cruziana dispar [Linnarsson, 1869a, p. 353]. Eophyton linnseanum [Linnarsson, 1869b, p. 399]. *Eophyton torelli [Linnarsson, 1869a, p. 351]. *Dictyonema sp. [Linnarsson, 1871, p. 13]. *Astylospongia radiata [Linnarsson, 1871, p. 13]. *Bythotrephis sp. [Linnarsson, 1871, p. 18]. Scotolithus mirabilis [Linnarsson, 1871, p. 18]. 390k. o (For stratigraphic position and association, see p. 146.) Lower Cambrian: Eophyton sandstone at Prestorp, north of the hill of Billingen, southeast of Lake Vennern, Province, of Skaraborg, Sweden. Mickwitzia monilifera. 3901 [Moberg and Segerberg, 1906, p. 65], (For stratigraphic position and association, see p. 145.) Upper Cam- brian: Obolus conglomerate at Klittberget, in Dalarne, Province of Kopparberg, Sweden. Obolus apollinis. 390m [Moberg and Segerberg, 1906, p. 65]. (For stratigraphic position and association, see p. 145.) Upper Cam- brian: Conglomerate overlying a glauconite sand at Horn, northern part of Oeland Island, Sweden. Obolus apollinis. 390n [U. S. National Museum]. (For stratigraphic position and association, see p. 145.) Upper Cambrian: Lime- stones of Olenus zone at Hunneberg, western boundary of the Province of Skaraborg, Sweden. Orusia lenticularis. ParaboUna spinulosa. 3900 [U. S. National Museum]. (For stratigraphic position and association, see p. 145.) Upper Cambrian : Arena- ceous shales at Andrarum, 20 miles (32 km.) northwest of Simrishamn, Province of Christianstad, Sweden. Orusia lenticularis. (Von Buch [1834, p. 48] cites this species from " aluminif erous schists" at Andrarum, and the two localities may be the same.) a The authority for the citation of this locality was mislaid and could not be traced in time for insertion in this volume. LOCALITIES. 2SI 390p [Davidson, 1869, p. 231]. (For stratigraphic position and association, see p. 145.) Upper Cambrian: At Kinnekulle, northeast of Lidkoping, Province of Skaraborg, Sweden. Orusia lenticularis. 392 [U. S. National Museum]. Upper Cambrian: Potsdam sandstone at Burgess, Canada. Lingulella (Lingulepis) acuminata. 392a [U. S. National Museum; seeWalcott, 1891b, p. 2.54]. Lower Cambrian: Limestones at L'Anseau Loup, on the north shore of the Straits of Belleisle, Labrador. Micromitra (Paterina) bella. *Micromitra (Paterina) labradorica. *Obolella chromatica. *Kutorgina cingulata. Nisusia festinata. *Nisusia (Jamesella) sp. undt. Orthis 2 sp. Palaeophycus incipiens. Archseocyathus profundus (Billings). Spirocyathus atlanticus (Billings). Coscinocyathus billingsi Walcott. Stenotheca elongata Walcott. Stenotheca rugosa (Hall). Hyolithes billingsi Walcott. Salterella pulchella Billings. Salterella rugosa Billings. Mesonacis vermontana (Hall). Olenellus logani Walcott (Geol. Survey Canada). Ptychoparia miser Billings. Protypus senectus Billings. Solenopleura (like S. nana Ford); 392b [Matthew, 1895b, p. 258]. Upper Cambrian: Sandstone at Beverly, township of Bastard, county of Leeds, Ontario, Canada. This sandstone corresponds to the passage beds above the massive Potsdam sandstone at Chateaugay Falls, New York. Lingulella (Lingulepis) acuminata. 392c [Billings, 1872a, p. 218]. Lower Cambrian: At the Straits of Belleisle, Labrador. *Bicia gemma. Obolella chromatica. Obolella crassa. Obolella desquamata=Obolella crassa. Botsfordia caslata. Quebecia circe. 392d [Billings, 1856, p. 34]. Upper Cambrian: Sandstone on Lot 11, 11th concession, township of Lansdowne, county of Leeds, Ontario, Canada. Lingulella (Lingulepis) acuminata. 392e [Billings, 1856, p. 34]. Upper Cambrian: Sandstone on Lot 22, 9th concession, township of Bastard, county of Leeds, Ontario, Canada. Lingulella (Lingulepis) acuminata. 392g [Dawson, 1888a, p. 55]. Middle? Cambrian (probably between the Middle and Upper Cambrian): Black shales at Little Metis, Province of Quebec, Canada. Obolella ida=Acrotreta sagittalis. 392h [Billings, 1859, p. 432]. Ordovician: Limestone of the " Chazy formation " in the valley of Ottawa River, above Carillon, Quebec, Canada. Obolus belli. 392i [Billings, 1865a, p. 220]. Lower Ordovician: Limestone at Phillipsburgh, Province of Quebec, Canada. Syntrophia calcifera. Bathyurus saffordi. , ■ 392] [U. S. National Museum], Lower Ordovician: Limestones of the "Quebec group " at Point Levis, Province of Quebec, Canada. *Syntrophia calcifera. 392 1 [Geological Survey of Canada]. Lower Cambrian : Arenaceous limestone at Point Amour, Straits of Belleisle, Labrador. Kutorgina cingulata. Obolella chromatica. Stenotheca cf . elongata Walcott. Discinella. Archaeocyathus. Olenellus sp.?. 392m. [U. S. National Museum]. (See 392i.) Upper Cambrian: Sandstone on the east shore of Missisquoi Bay, 1.5 miles (2.4 km.) south of Phillipsburgh, Province of Quebec, Canada (C. D. Walcott, ISSS). Lingulella (Lingulepis) acuminata. 392n [U. S. National Museum]. Upper Cambrian: Sandstone in eastern Canada, exact locality unknown (Geol. Survey Canada, 1876). Lingulella (Lingulepis) acuminata. 282 CAMBEIAN BRACHIOPODA. 3920 [U. S. National Museum]. Lower Cambrian: Arenaceous limestone collected somewhere in Vermont, exact locality unkno\Yn (T. C. Wooster). Rustella edsoni. 392p [U. S. National Museum]. Nisusia festinata. Lower Cambrian: Shale on the Jewell farm, Franklin County, Vt. 395 (references follow species). (For stratigraphic position and association, see p. 143.) Upper Cambrian : Obolus sandstone at Joa, near Jegelecht, 12 miles (19.3 km.) east of Reval, Government of Esthonia, Russia. Obolus apollinis [Mickwitz, 1896, p. 137]. Obolus apollinis ingricus [Mickwitz, 1896, p. 139]. *Obolus apollinis maximus [Mickwitz, 1896, p. 144, and U. S. National Museum]. *Obolus apollinis quenstedti [Mickwitz, 1896, p. 145]. *Obolus eichwaldi [Mickwitz, 1896, p. 155]. *Obolus elegans [Mickwitz, 1S96, p. 158]. *Obolus panderi [Mickwitz, 1896, p. 151]. *Obolus schmidti [Mickwitz, 1896, p. 153]. *Obolus volborthi [Mickwitz, 1896, p. 157]. *Obolus (Schmidtia) acuminatus [Mick-witz, 1896, p. 183, and LT. S. National Museum]. *Obolus (Schmidtia) acuminatus alatus [Mickwitz, 1896, p. 184]. *Obolus (Schmidtia) acuminatus humeratus [Mickwitz' 1896, p. 186]. Obolus (Schmidtia) acuminatus subtriangularis [Mick- witz, 1896, p. 187]. Obolus (Schmidtia) celatus (U. S. National Museum). Obolus (Schmidtia) celatus preecisus [Mickwitz, 1896, p. 166]. *Obolus (Schmidtia) crassus [Mickwitz, 1896, p. 192, and U. S. National Museum]. Obolus (Schmidtia) crassus angulatus [Mickwitz, 1896, p. 194]. *Obolus (Schmidtia) obtusus [Mickwitz, 1896, p. 171, and U. S. National Museum]. Obolus (Schmidtia) obtusus acutus [Mickwitz, 1896, p. 173]. Obolus (Schmidtia) obtusus ellipticus [Mickwitz, 1896, p. 178], Obolus (Schmidtia) obtusus extenuatus [Mickwitz, 1896, p. 177]. Obolus (Schmidtia) obtusus latus [Mickwitz, 1896, p. 175]. Obolus (Schmidtia) obtusus longus [Mickwitz, 1896, p. 172]. Obolus (Schmidtia) obtusus minutus [Mickwitz, 1896, p. 176]. Lingulella (Leptembolon) lingulseformis (U. S. National Museum). Keyserlingia buchi (U. S. National Museum). 395a (references follow species). (For stratigraphic position and association, see p. 143.) Upper Cambrian : Obolus sandstone at Tihala, near Jegelecht, about 12 miles (19.3 km,) east of Reval, Government of Esthonia, Russia. Obolus apollinis ingricus [Mickwitz, 1896, p. 139]. Obolus apollinis quenstedti [Mickwitz, 1896, p. 144]. Obolus (Schmidtia) acuminatus [Mickwitz, 1896, p. 183]. Obolus (Schmidtia) acuminatus alatus [Mickwitz, 1896, p. 184]. Obolus (Schmidtia) acuminatus humeratus [Mickwitz, 1896, p. 186]. Obolus (Schmidtia) celatus prsecisus [Mickwitz, 1896, p. 166]. Obolus (Schmidtia) crassus [Itfickwitz, 1896, p. 192]. 395b (references follow species) . (For stratigraphic position and association, see p. 143.) Upper Cambrian: Obolus sandstone at Ilgast, Government of Esthonia, Russia. Obolus apollinis (U. S. National Museum). Obolus elegans (U. S. National Museum). Obolus (Schmidtia) acuminatus [Mickwitz, 1896, p. 183]. Obolus (Schmidtia) acuminatus alatus [Mickwitz, 1896, p. 184]. Obolus (Schmidtia) acuminatus humeratus [Mickwitz, 1896, p. 186]. Obolus (Schmidtia) acuminatus subtriangularis [Mick- witz, 1896, p. 187]. Obolus (Schmidtia) celatus praecisus [Mickwitz, 1896, p. 166]. Obolus (Schmidtia) crassus [Mickwitz, 1896, p. 192]. Obolus (Schmidtia) crassus angulatus [Mickwitz, 1896, p. 194]. Obolus (Schmidtia) obtusus [Mickwitz, 1896, p. 171]. Obolus (Schmidtia) obtusus ellipticus [Mickwitz, 1896, p. 178]. Keyserlingia buchi (U. S. National Museum). 395c (references follow species). (For stratigraphic position and association, see p. 143.) Upper Cambrian: Obolus sandstone at Asserien, 75 miles (121 km.) east of Reval, Government of Esthonia, Russia. Obolus (Schmidtia) acuminatus [Mickwitz, 1896, p. 183]. Obolus (Schmidtia) acuminatus alatus [Mickwitz, 1896, p. 184]. *Obolus (Schmidtia) celatus [Volborth, 1869, p. 212]. Obolus (Schmidtia) celatus praecisus [Mickwitz, 1896, p. 166]. Obolus (Schmidtia) crassus [Mickwitz, 1896, p. 192]. 395d (references follow .species). (For stratigraphic position and association, see p. 143.) Upper Cambrian: Obolus sandstone at Ontika, about 95 miles (153 km.) east of Reval and 30 miles (48 km.) west of Narwa, Govern- ment of Esthonia, Russia. Obolus (Schmidtia) acuminatus [Mickwitz, 1896, p. 183]. Obolus (Schmidtia) acuminatus alatus [Mickwitz, 1896, p. 184]. Obolus (Schmidtia) celatus prsecisus [Mickwitz, 1896, p. 166]. Obolus (Schmidtia) crassus [Mickwitz, 1896, p. 192]. LOCALITIES. 283 395e (references follow species). (For stratigraphic position and association, see p. 144.) Upper Cambrian: Obolus sandstone at Isenhof, 85 miles (137 km.) east of Reval, Government of Esthonia, Russia. Obolus (Schmidtia) acuminatus [Mickwitz, 1896, p. 183]. Obolus (Schmidtia) acuminatus alatus [Mickwitz, 1896, p. 184J. Obolus (Schmidtia) celatus praecisus [Mickwitz, 1896, p. 166]. Obolus (Schmidtia) crassus [Mickwitz, 1896, p. 192]. 395t [Mickwitz, 1896, p. 142], (For stratigraphic position and association, see p. 144.) Upper Cambrian: Obolus conglomerate throughout the East Baltic region, Government of Esthonia, Russia. Obolus apoUinis. Obolus apollinis maximus. 395g (references follow species). (For stratigraphic position and association, see p. 144.) Upper Cambrian ; Obolus conglomerate at Joa, near Jegelecht, 12 miles (19.3 km.) east of Reval, Government of Esthonia, Russia. *Obolus triangularis [Mickwitz, 1896, p. 147]. Obolus triangularis inornatus [Mickwitz, 1896, p. 149]. Obolus (Schmidtia) celatus [Mickwitz, 1896, p. 163]. Obolus (Schmidtia) celatus orbiculatus [Mickwitz, 1896, p. 165]. Obolus (Schmidtia"! celatus prsecisus [Mickwitz, 1896, p. 166]. 3951i (references follow species). Upper Cambrian: Obolus conglomerate at Tihala, near Jegelecht, about 12 miles (19.3 km.) east of Reval, Government of Esthonia, Russia. Obolus (Schmidtia) celatus [Mickwitz, 1896, p. 163]. Obolus (Schmidtia) celatus orbiculatus [Mickwitz, 1896, p. 165]. Obolus (Schmidtia) celatus prsecisus [Mickwitz, 1896, p. 166]. 3951 (references follow species). (For stratigraphic position and association, see p. 144.) Upper Cambrian: Obolus conglomerate at Ilgast, Government of Esthonia, Russia. Obolus (Schmidtia) celatus prsecisus [Mickwitz, 1896, p. 166]. Obolus triangularis [Mickwitz, 1896, p. 147]. Obolus (Schmidtia) celatus [Mickwitz, 1896, p. 163]. Obolus (Schmidtia) celatus orbiculatus [Mickwitz, 1896, p. 165]. 395j (references follow species). (For stratigraphic position and association, seep. 144.) Upper Cambrian: Obolus conglomerate at Asserien, 75 miles (121 km.) east of Reval, Government of Esthonia, Russia. Obolus (Schmidtia) celatus orbiculatus [Mickwitz, 1896, p. 165]. Obolus (Schmidtia) celatus prsecisus [Mickwitz, 1896, p. 166]. 395k (references follow species). (For stratigraphic positionand association, see p. 144.) Upper Cambrian: Obolus conglomerate at Ontika, about 95 miles (153 km.) east of Reval and 30 miles (48 km.) west of Narwa, Gov- ernment of Esthonia, Russia. Obolus (Schmidtia) celatus orbiculatus [Mickwitz, 1896, p. 165]. Obolus (Schmidtia) celatus prsecisus [Mickwitz, 1896, p. 166]. 395 1 (references follow species) . (For stratigraphic position and association, see p . 144. ) Upper Cambrian : Obolus conglomerate at Isenhof, 85 miles (137 km.) east of Reval, Government of Esthonia, Russia. Obolus (Schmidtia) celatus orbiculatus [Mickwitz, 1896, p. 165]. Obolus (Schmidtia) celatus prsecisus [Mickwitz, 1896, p. 166]. 395m (references follow species). (For stratigraphic position and association, see p. 144.) Upper Cambrian: Sand- stone below the Obolus conglomerate at Joa, near Jegelecht, 12 miles (19.3 km.) east of Reval, Government of Esthonia, Russia. Obolus (Schmidtia) celatus orbiculatus [Mickwitz, 1896, p. 165]. Obolus (Schmidtia) celatus prsecisus [Mickwitz, 1896, p. 166]. 395n (references follow species). (For stratigraphic position and association, see p. 144.) Upper Cambrian: Sand- stone below the Obolus conglomerate at Tihala, near Jegelecht, about 12 miles (19.3 km.) east of Reval, Government of Esthonia, Russia. Obolus (Schmidtia) celatus orbiculatus [Mickwitz, 1896, p. 165]. Obolus (Schmidtia) celatus prsecisus [Mickwitz, 1896, p. 166]. 3950 (references follow species). (For stratigraphic position and association, see p. 144.) Upper Cambrian: Sand- stone below the Obolus conglomerate at Ilgast, Government of Esthonia, Russia. Obolus (Schmidtia) celatus [Mickwitz, 1896, p. 163]. Obolus (Schmidtia) celatus orbiculatus [Mickwitz, 1896, p. 165]. Obolus (Schmidtia) celatus prsecisus [Mickwitz, 1896, p. 166]. 395p (references follow species). (For stratigraphic position and association, see p. 144.) Upper Cambrian: Sand- stone below the Obolus conglomerate at Asserien, 75 miles (121 km.) east of Reval, Government of Esthonia, Russia. Obolus (Schmidtia) celatus orbiculatus [Mickwitz, 1896, p. 165]. Obolus (Schmidtia) celatus prsecisus [Mickwitz, 1896, p. 166]. 284 CAMBRIAN BRACHIOPODA. 395q (references ioUow species). (For stratigraphic position and association, see p. 144.) Upper Cambrian: Sand- stone below the Obohis conglomerate at Ontika, about 95 miles (153 km.) east of Reval and 30 miles (48 km.) west of Narwa, Government of Esfhonia, Russia. Obolus (Schmidtia) celatus orbiculatus [Mickwitz, 1896, p. 165]. Obolus (Schmidtia) celatus prascisus [Mickwitz, 1896, p. 166]. 395r (references follow species). (For stratigraphic position and association, see p. 144.) Upper Cambrian: Sandstone below the Obolus conglomerate at Isenhof, 85 miles (137 km.) east of Reval, Government of Esthonia, Russia. Obolus (Schmidtia) celatus orbiculatus [Mickwitz, 1896, p. 165]. Obolus (Schmidtia) celatus prsecisus [Mickwitz, 1896, p. 166]. 395s [Mickwitz, 1896, p. 163]. (For stratigraphic position and association, see p. 144.) Upper Cambrian: Schmidtia conglomerate (part of the Obolus conglomerate) at Asserien, 75 miles (121 km.) east of Reval, Government of Esthonia, Russia. Obolus (Schmidtia) celatus. 395t [Mickwitz, 1896, p. 163]. (For stratigraphic position and association, see p. 144.) Upper Cambrian: Schmidtia conglomerate (part of the Obolus conglomerate) at Ontika, about 95 miles (153 km.) east of Reval and 30 miles (48 km.) west of Narwa, Government of Esthonia, Russia. Obolus (Schmidtia) celatus. 39511 [Mickwitz, 1896, p. 163]. (For stratigraphic position and association, see p. 144.) Upper Cambrian: Schmidtia conglomerate (part of the Obolus conglomerate) at Isenhof, 85 miles (137 km.) east of Reval, Government of Esthonia, Russia. Obolus (Schmidtia) celatus. 395v [Eichwald, 1843, p. 147]. (For stratigraphic position and association, see p. 143.) Passage beds between the Upper Cambrian and the Ordovician: Sandstone on Odensholm Island, about 55 miles (88.6 km.) west of Reval, Government of Esthonia, Russia. Obolus (Mickwitzella) siluricus. 395w [Eichwald, 1843, p. 147]. (For stratigraphic position and association, see p. 143.) Passage beds between the Upper Cambrian and the Ordovician: In the chlorite-bearing sands in the limestone beds at Pawlowsk, near St. Petersburg, Russia. Obolus (Acritis) antiquissimus. Obolus (Mickwitzella) siluricus. 395x [Lamansky, 1901, p. 617]. (For stratigraphic position and association, see p. 143.) Passage beds between the Upper Cambrian and the Ordovician: Glauconitic sandstone (correlated by Lamansky, 1901, p. 617, with the Upper Cambrian Ceratopyge slate) in the vicinity of Baltischport, about 30 miles (48 km.) west of Reval, Government of Esthonia, Russia. Obolus (Mickwitzella) siluricus. 395y [Kutorga, 1848, p. 281]. (For stratigraphic position and association, see p. 143.) Passage beds between the Upper Cambrian and the Ordovician: Sandstone on Pulkowa Brook, near St. Petersburg, Russia. Obolus (Mickwitzella) siluricus. 395z (references follow species). (For stratigraphic position and association, see p. 143.) Upper Cambrian: Obolus sandstone at Jamburg on Louga (Luga) River, Government of St. Petersburg, Russia. *Obolus apollinis [Eichwald, 1829, p. 274, and U. S. National Museum]. *Obolus apollinis ingricus [Eichwald, 1829, p. 274]. Obolus apollinis quenstedti [Mickwitz, 1896, p. 144]. 396 (references follow species). (For stratigraphic position and association, see p. 143.) Passage beds between the Upper Cambrian and the Ordovician: "Glauconite sandstone" at Baltischport, 30 miles (48 km.) west of Reval, Government of Esthonia, Russia. Obolus (Mickwitzella) siluricus [Mickwitz, 1896, p. 198, and U. S. National Museum]. Lingulella (Leptembolon) lingulseformis [Mickwitz, 1896, p. 203]. 396a (references follow species). (For stratigraphic position and association, see p. 143.) Passage beds between the Upper Cambrian and the Ordovician: "Glauconite sandstone" at Leppiko, near Leetz, on the eastern side of the Baltischport peninsula, about 25 miles (40.3 km.) west of Reval, Government of Esthonia, Russia. *Obolus (Mickwitzella) silm-icus [Mickwitz, 1896, p. 198, and U. S. National Museum]. *Lingulella (Leptembolon) lingulseformis [Mickwitz, 1896, p. 203, and U. S. National Museum]. *Lingulella (Leptembolon) lingulseformis solidus [Mickwitz, 1896, p. 205]. 396b (references follow species). (For stratigraphic position and association, see p. 143.) Passage beds between the Upper Cambrian and the Ordovician: "Glauconite sandstone" at Fall, 15 miles (24 km.) west of Reval, Government of Esthonia, Russia. Obolus (Mickwitzella) siluricus [Mickwitz, 1896, p. 198]. Lingulella (Leptembolon) linguleeformis [Mickwitz, 1896, p. 203]. LOCALITIES. 285 396c (references follow species). (For stratigrapliic position and. association, see p. 143.) Passage beds between the Upper Cambrian and the Ordovician: "Glauconite sandstone" at the mouth of Fahna Brook, east of Fall, about 15 miles (24 km.) west of Reval, Government of Esthonia, Russia. Obolus (Mickwitzella) silui-icus [Mickwitz, 1S96, p. 198]. Lingulella (Leptembolon) lingulseformis [Mickwitz, 1896, p. 203]. 396d (references follow species). (For stratigraphic position and association, see p. 143.) Passage beds between the Upper Cambrian and the Ordovician: "Glauconite sandstone" at Domglint in Reval, Government of Esthonia, Russia. Obolus (Acritis) antiquissimus (U. S. National Museum). Obolus (Acritis) antiquissimus ventrosus [?]. Lingulella (Leptembolon) lingulseformis pilickwitz, 1896, p. 203]. 396e [Mickwitz, 1896, p. 198]. (For stratigraphic position and association, see p. 143.) Passage beds between the Upper Cambrian and the Ordovician: "Glauconite sandstone " in the eastern part of the east Baltic region. Government of Esthonia, Russia. Obolus (Mickwitzella) siluricus. 396f [Mickwitz, 1896, p. 204]. (For stratigraphic position and association, see p. 143.) Passage beds between the Upper Cambrian and the Ordovician: "Glauconite sandstone " in the western part of the east Baltic region, Russia. Lingulella (Leptembolon) lingulseformis. 396g [Eichwald, 1843, p. 143]. (For stratigraphic position and association, see p. 143.) Passage beds between the Upper Cambrian and the Ordovician: In the upper limestone at Reval, Government of Esthonia, Russia. *Obolus (Acritis) antiquissimus. 39611 [Mickwitz, 1896, p. 213]. (For stratigraphic position and association, see p. 143.) Passage beds between the Upper Cambrian and the Ordovician: "Glauconite limestone" at Tischer, 10 miles (16 km.) west of Reval, Government of Esthonia, Russia. Obolus (Acritis) antiquissimus. 3961 [Mickwitz, 1896, p. 213]. (For stratigraphic position and association, see p. 143.) Passage beds between the Upper Cambrian and the Ordovician: "Glauconite limestone" at Fall, 15 miles (24 km.) west of Reval, Government of Esthonia, Russia. Obolus (Acritis^ antiquissimus. 396j [Mickwitz, 1896, p. 213]. (For stratigraphic position and association, see p. 143.) Passage beds between the Upper Cambrian and the Ordovician: "Glauconite limestone" at Nommeweske, near Palms, Government of Esthonia, Russia. Obolus (Acritis) antiquissimus. 396k [Mickwitz, 1896, p. 213]. (For stratigraphic position and association, see p. 143.) Passage beds between the Upper Cambrian and the Ordovician: "Glauconite limestone" at Iswos on the Wolchow, Government of St. Petersburg, Russia. Obolus (Acritis) antiquissimus. 3961 [Mickwitz, 1896, p. 213]. (For stratigraphic position and association, see p. 143.) Passage beds between the Upper Cambrian and the Ordovician: "Glauconite limestone" at Piilkowa, near St. Petersburg, Russia. Obolus (Acritis) antiquissimus. 396m [Mickwitz, 1896, p. 213]. (For stratigraphic position and association, see p. 143.) Passage beds between the Upper Cambrian and the Ordovician: "Lower lenticular layer" of the "glauconite limestone" at Saggad, east of Palms, Government of Esthonia, Russia. Obolus (Acritis) antiquissimus. 396)1 [Mickwitz, 1896, p. 213]. (For stratigraphic position and association, see p. 143.) Passage beds between the Upper Cambrian and the Ordovician: White limestone between the "glauconite limestone" and the sandy representative of the "Vaginatum limestone" at Leppiko, near Leetz, on the eastern side of the Baltischport peninsula, about 25 miles (40.3 km.) west of Reval, Government of Esthonia, Russia. Obolus (Acritis) antiquissimus. 3960 [Mickwitz, 1896, p. 213]. (For stratigraphic position and association, see p. 143.) Passage beds between the Upper Cambrian and the Ordovician: "Glauconite limestone" in the entire western part of the east Baltic region. Government of Esthonia, Russia. Obolus (Acritis) antiquissimus. 396p [Mickwitz, 1896, p. 213]. (For stratigraphic position and association, see p. 143.) Passage beds between the Upper Cambrian and the Ordovician: Strata between the " lower lenticular layer " and the " Vaginatum limestone" proper at Nommeweske, near Palms, Government of Esthonia, Russia. Obolus (Acritis) antiquissimus. 286 CAJVIBRIAN BRACHIOPODA. 396q [Schmidt, 1888, p. 24]. (For stratigraphic position and association, see p. 144.) Lower Cambrian: Upper boundary of the blue clay with the Fuc'oid sandstone (the " Mickwitzia conglomerate" [Schmidt, 1888, p. 24]), at Reval, Government of Esthonia, Russia. Mickwitzia monilifera. 396r [Schmidt, 1888, p. 24]. (For stratigraphic position and association, see p. 144.) Lower Cambrian: In the "upper strata" at Streitberg, near Reval, Government of Esthonia, Russia. Mickwitzia monilifera, 396s [Schmidt, 1888, p. 24]. (For stratigraphic position and association, see p. 144.) Lower Cambrian: In loose blocks on Kosch Brook near Likkat, near Reval, Government of Esthonia, Russia. Mickwitzia monilifera. 396t [Schmidt, 1888, p. 24]. (For stratigraphic position and association, see p. 144.) Lower Cambrian: At the sandstone capes of Ziegelskoppel, Kakkomaggi (also Rocca al Mare), near Reval, Government of Esthonia, Russia. Mickwitzia monilifera. 396u [Schmidt, 1888, p. 24]. (For stratigraphic position and association, see p. 144.) Lower Cambrian: In loose blocks on the lower course of Jaggowal Brook, about 20 miles (32.2 km.) east-southeast of Reval, Govern- ment of Esthonia, Russia. Mickwitzia monilifera. Traces of Olenellus. 396v [Schmidt, 1888, p. 24, and U. S. National Museum]. (For stratigraphic position and association, see p. 144.) Lower Cambrian: At the upper boundary of a dolomitic sandstone with which the Olenellus stratum begins, below the cement factory on Kunda Brook, Government of Esthonia, Russia. Mickwitzia monilifera. Traces of Olenellus. 396w [Schmidt, 1888, p. 24]. (For stratigraphic position and association, see p. 144.) Lower Cambrian: In the glauconitic sands above the main mass of the clay, below the cement factory on Kunda Brook, Govern- ment of Esthonia, Russia. Mickwitzia monilifera. 396x [Eichwald, 1843, p. 146]. (For stratigraphic position and association, see p. 143.) Passage beds between the Upper Cambrian and the Ordovician: In the chlorite-bearing sands in the limestone beds at Baltisch- port, about 30 miles (48 km.) west of Reval, Government of Esthonia, Russia. Obolus (Acritis) antiquissimus. Obolus (Mickwitzella) siluricus. 396y [Eichwald, 1843, p. 147]. (For stratigraphic position and association, see p. 143.) Passage beds between the Upper Cambrian and the Ordovician: In the chlorite-bearing sands in the limestone beds at Reval, Government of Esthonia, Russia. Obolus (Acritis) antiquissimus. Obolus (Mickwitzella) siluricus. 396z [Kutorga, 1848, p. 283]. (See 336g.) (For stratigraphic position and association, see p. 143.) Passage beds between the Upper Cambrian and the Ordovician: Limestone in the vicinity of Zarskoe Selo, Government of St. Petersburg, Russia. Obolus (Acritis) antiquissimus. Localities C1-C75, Carnegie Institution of Washington Expedition to China." CI (just above C4, same section; just below C2, same section; about 75 feet below C62, which occm's at a locality 3 miles east; about same horizon as CIO, different section; about 150 feet below C12, same section). Middle Cambrian: Lower shale member of the Kiulung group [Blackwelder, 1907a, pp. 37 and 40 (part of the third list of fossils), and fig. 10 (bed 4), p. 38], 2 miles (3.2 km.) south of Yenchuang, Sintai district, Shantung, China (Eliot Blackwelder, 11-27-1903). *Obolus minimus. Obolus (Westonia) blackwelder!. Acrotreta pacifica. Acrotreta shantungensis?. Protospongia chloris Walcott. Platyceras chronus Walcott. Hyolithes cybele Walcott. Agnostus chinensis Dames. Dorypyge richthofeni Dames. Inouyia divi (Walcott). Anomocarella albion Walcott. Anomocarella chinensis Walcott. Lisania agonius (Walcott). Dolichometopus alceste Walcott?. Dolichometopus decerto Walcott. Dolichometopus deois Walcott. a See the explanatory paragraphs on pp. 160-161. LOCALITIES. 287 C2 (above C4, same section; just above CI, same section; about same horizon as ClO, different section). Middle Cambrian: Lower shale member of the Kiulung group [Blackwelder, 1907a, pp. 37 and 40 (part of the third list of fossils), and iig. 10 (beds 4 and 5), p. 38], 2 miles (3.2 km.) south of Yenchuang, Sintai district. Shantung, China (Eliot Blackwelder, 11-30-1903). Obolus (Westonia) blackwelderi. Acrotreta pacifica. Protospongia chloris Walcott. Hyolithes cybele Walcott. Orthotheca cyrene dryas Walcott. Agnostus chinensis Dames. Dorypyge bispinosa Walcott. Anomocare latelimbatum Dames. Anomocarella albion Walcott. Anomocarella biston (Walcott). Anomocarella chinensis Walcott. Coosia? daunus (Walcott). Lisania agonius (Walcott). Dolichometopus derceto Walcott. Dolichometopus deois Walcott. Lonchocephalus tellus (Walcott). C3 (about 100 feet above the horizon of C60, different section; about 175 feet below the horizon of C8, different sections). Lower Cambrian: Lower part of the Manto shale formation [Blackwelder, 1907a, p. 28 (list of fossils at bottom of page), and fig. 8a (bed 20), p. 28], on the southeast slope of Hulushan, 2.5 miles (4 km.) southwest of Yenchuang, Sintai district. Shantung, China (Eliot Blackwelder, 11-30-1903). *Billingsella richthofeni. Stenotheca rugosa chinensis Walcott. Hyolithes delia Walcott. Redlichia nobilis Walcott. Ptychoparia (Emmrichella) constricta (Walcott.) C4 (just below CI, same section; same horizon as C57, different section). Middle Cambrian: In limestone nodules at the base of the lower shale member of the Kiulung group [Blackwelder, 1907a, pp. 37 and 40 (second list of fossils), and fig. 10 (bed 4), p. 38], 3 miles (4.8 km.) southwest of Yenchuang, Sintai district. Shantung, China (Eliot Blackwelder, 11-27-1903). *Acrothele matthewi eryx. Acrotreta pacifica. Protospongia chloris Walcott. Platyceras chronus Walcott. Hyolithes cybele Walcott. Orthotheca delphus Walcott. Agnostus chinensis Dames. Anomocarella albion Walcott. Anomocarella chinensis Walcott. Lisania alala (Walcott). Dolichometopus alceste Walcott. Dolichometopus deois Walcott. CS (about 25 feet above C8, same section; about 40 feet below C63, same section). Middle Cambrian: Lower lime- stone member of the Kiulung group [Blackwelder, 1907a, pp. 37 and 39 (first list of fossils), and fig. 8a (bed 30), p. 29], 3,2 miles (5.1 km.) southwest of Yenchuang, Sintai district, Shantung, China (Eliot Blackwelder, 11-23-1903). On the figure this bed is placed as occurring below the line dividing the Manto from the Kiulung, but on the basis of the fauna contained in the limestone it is referred to the base of the Kiulung. The text (p. 39) places the boundary between the Kiulung and the Manto, 15 feet below C5. Micromitra (Iphidella) pannula ophirensis. *Acrotreta pacifica. Globigerina? mantoensis Walcott. Inouyia divi (Walcott). Anomocare butes Walcott. Anomocare sp. Dolichometopus sp. C6 (about 120 feet above C12, same section; about 20 feet below C61, same section). Middle Cambrian: Thin platy limestone in the upper shale member of the Kiulung group just below the Chaumitien limestone [Blackwelder, 1907a, pp. 37 and 41 (second list of fossils), and fig. 10 (bed 12), p. 38], 2.5 miles (4 km.) southwest of Yenchuang, Sintai district. Shantung, China (Eliot Blackwelder, 11-25-1903). *Acrothele minuta. *Obolus (Westonia) blackwelderi. *Dicellomus parvus. Agnostus douvillei Bergeron. Blackwelderia sinensis (Bergeron). Drepanura ketteleri Monke. Drepanura premesnili Bergeron. Ptychoparia (Emmrichella) bromus (Walcott). Redlichia sp. undt. Walcott. Shantungia spinifera Walcott. Stephanocare? monkei Walcott. Stephanocare richthofeni Monke. Stephanocare sinensis (Bergeron). Stephanocare? sp. undt. Walcott. Liostracina krausei Monke. C7 (just above C9, same section; about same horizon as C52, different sections; about 200 feet below CIO, same section). Middle Cambrian: Lower limestone member of the Kiulung group [Blackwelder, 1907a, pp. 37 and 39 (last list of fossils), and fig. Sa (bed 33), p. 29], 2.2 miles (3.5 km.) southwest of Yenchuang, Sintai district. Shantung, China (Eliot Blackwelder, 11-23-1903). Lingulella damesi. Lingulella (Lingulepis) eros. Inouyia abaris (Walcott). Inouyia titiana (Walcott). Agraulos dolon Walcott. Anomocarella subrugosa (Walcott). Anomocarella thraso (Walcott.) 288 CAMBRIAN BRACHIOPODA. C9 (just below C7, same section; about 25 feet above CG3, same section; about same horizon as C52, different sec- tions). Middle Cambrian: Lower limestone member of the Kiulung group [Blackwelder, 1907a, pp. 37 and 39 (third list of fossils), and fig. 8a (bed 33), p. 29], 3 miles (4.8 km.) southwest of Yenchuang, Sintai district, Shantung, China (?, 11-27-1903). *Micromitra (Paterina) labradorica orientalis. I Coosia decelus (Walcott). Inouyia abaris (Walcott). I Anomocare minus Dames. CIO (about 200 feet above C7, same section; about same horizon as CI, C2, and C4, different section). Middle Cambrian: Lower shale member of the Kiulung group [Blackwelder, 1907a, pp. 37 and 40 (part of the third list of fossils), and fig. 8a (bed 35), p. 29], about 3 miles (4.8 km.) southwest of Yenchuang, Sintai district> Shantung, China (EUot Blackwelder, 11-23-1903). *Lingulella damesi. Anomocarella temenus (Walcott). Menocephalus sp. undt. Walcott. C12 (about 120 feet below C6, same section; about 75 feet above C62, same section but at a locality 3 miles east; C13 includes the horizon represented by C12; about 150 feet above CI, same section). Middle Cambrian: Gray limestone near the top of the middle limestone member of the Kiulung group [Blackwelder, 1907a, pp. 37 and 41 (part of first list of fossils), and fig. 10 (bed 7), p. 38], 3.25 miles (5.2 km.) southwest of Yenchuang, Sintai district. Shantung, China (Eliot Blackwelder and Li San, 11-25-1903). Acrotreta pacifica. Inouyia acalle (Walcott). Lisania ajax (Walcott). Damesella blackwelderi Walcott. Blackwelderia alastor (Walcott). Anomocarella tutia (Walcott). Pterocephalus asiatica Walcott. Teinistion alcon (Walcott). C17 (about 180 feet below C23, same section; about 35 feet above C20, adjacent sections; about 160 feet below C28, adjacent sections). Lower Cambrian: Ferruginous limestone nodules in the brown sandy shales at the top of the Manto shale [Blackwelder, 1907a, p. 27 (list of fossils at top of page) and fig. 6 (bed 15), p. 25], at Changhia, Shantung, China (Eliot Blackwelder, 10-31-1903). Obolella asiatica. I Ptychoparia impar Walcott. Ptychoparia aclis Walcott. | Ptjrchoparia granosa Walcott. C20 (about 15 feet above C31, same section; about 35 feet below C17, different sections). Lower Cambrian: Central part of the Manto shale formation [Blackwelder, 1907a, p. 26 (last list of fossils) and fig. 6 (bed 14), p. 25], on the west side of an isolated butte 1 mile (1.6 km.) south of Changhia, Shantung, China (Eliot Black- welder, 10-27-1903). Billingsella richthofeni?. Ptychoparia aclis Walcott. Ptychoparia (Emmrichella) mantoensis (Walcott). C22 (about same horizon as C19, C24, and C26, same section; above CIS, same section). Middle Cambrian: Chang- hia limestone in upper oolitic portion [Blackwelder, 1907a, pp. 22 and 33 (part of last list of fossils)], at Changhia, Shantung, China (Eliot Blackwelder, 10-29-1903). *Acrotreta lisani. Hyolithes cybele Walcott. Anomocarella temenus (Walcott). Lisania alala (Walcott). Lisania bura (Walcott). Menocephalus admeta Walcott. Menocephalus acantha (Walcott). C23 (about 180 feet above 017, same section; about 25 feet above C28, different sections). Middle Cambrian: Upper part of thin-bedded gray oolitic limestone at the base of the Changhia formation [Blackwelder, 1907a, p. 32 (second list of fossils) and fig. 6 (bed 20), p. 25], 50 feet below the base of the cliffs 1 mile (1.6 km.) east-southeast of Changhia, Shantung, China (Eliot Blackwelder, 10-27-1903). Acrothele rara?. Orthotheca daulis Walcott. Agraulos abrota Walcott. Anomocarella tatian (Walcott). Ptychoparia (Emmrichella) eriopia (Walcott). Ptychoparia (Emmrichella) theano (Walcott). C24 (about same horizon as C19, C22, and C26, same section; above C18, same section; about same horizon as C25, different section). Middle Cambrian: Near top of black oolitic group in the uppermost layers of the Changhia formation [Blackwelder, 1907a, p. 33 (part of last list of fossils)], 2 miles (3.2 km.) east of Changhia, Shantung, China. Acrotreta cf. pacifica. Agnostus sp. undt. Inouyia divi (Walcott). Dolichometopus dirce Walcott. Dorypyge richthofeni Dames. LOCALITIES. 289 C26 (about same horizon as C19, C22, and C24, same section; above CIS, same section). Middle Cambrian: Upper portion of the Changhia limestone, near top of black oolitic group [Blackwelder, 1907a, p. 33 (part of last list of fossils)], 2 miles (3.2 km.) north-northeast of Changhia, Shantung, China (Eliot Blackwelder, 10-29-1903). Eoorthis sp. undt. Anomocare? daulis Walcott. Crepicephalus damia Walcott. C28 (about 200 feet above C20, same section; about 160 feet above 017, adjacent sections; about 25 feet below C23, different sections). Middle Cambrian: Thin-bedded oolitic limestone at the base of the Changhia lime- stone [Blackwelder, 1907a, p. 32 (first list of fossils) and fig. 6 (bed 20), p. 25], just above the shales in the face of the cliff 1 mile (1.6 km.) east-southeast of Changhia, Shantung, China (Eliot Blackwelder, 10-29-1903). *Eoorthis agreste. Anomocarella tones (Walcott). Anomocarella toxeus (Walcott). Inouyia thisbe Walcott. Bathyuriscus. . 032 (see also C32', other drift blocks at the same locality). Middle Cambrian: A fine-grained bluish-black lime- stone bowlder believed to have come from the lower part of the Kisinling limestone [Blackwelder, 1907b, p. 272], collected in river drift 1 mile (1.6 km.) south of Chonpinghien, on Nanidang River, southern Shensi, China (Bailey Willis and Eliot Blackwelder, 5-28-1904). Obelus shansiensis. Dicellomus parvus. Acrotreta shantungensis. Orthotheca doris Walcott. Microdiscus orientalis Walcott. Aluta bergeroni (Walcott). Aluta enyo (Walcott). Aluta eris (Walcott). Aluta fragilis (Walcott). Aluta sterope (Walcott). Aluta woodi (Walcott). 032' (see C32, another drift block at the same locality). Lower Cambrian: A limestone bowlder collected in river drift 1 mile (1.6 km.) south of Chonpinghien, on Nankiang River, southern Shensi, China (Bailey Willis and Eliot Blackwelder, 5^28-1904). *Obolella asiatica. Hyolithes sp. undt. 036 (about same horizon as C45, different section; about same horizon as C50, same section; above C6S, same section; about same horizon as C47, same section). Upper Cambrian: Upper part of the Chaumitien limestone [Blackwelder, 1907a, p. 36 (part of third list of fossils), and fig. 9 (bed 2), p. 35], at Chaumitien, Changhia district. Shantung, China (Eliot Blackwelder, 10-22-1903). Billingsella pumpellyi. Anomocarella baucis Walcott. 037 (about same horizon as C72, same section; about 50 feet above C71, same section; about 200 feet below C73, same section; about 225 feet below C74, same section). Middle Cambrian: Upper part of the Kichou lime- stone, in dense black limestone nodules in green-gray shales 10 feet below the base of the cliff limestone, 8 miles (12.8 km.) south of Tinghianghien, Shansi, China (Eliot Blackwelder, 2-24-1904). The fossils from this locality are not listed, but the presence of Cambrian strata at the locality is mentioned by Willis and Blackwelder [1907, p. 146]. *Obolus shansiensis. Acrotreta shantungensis. Anomocare megalurus (Walcott). 054 (same horizon as C41, C49, and C56; about same horizon as C34 and 038, different sections). Upper Cam- brian: Lower part of Chaumitien limestone [Blackwelder, 1907a, p. 42 (part of last list of fossils)], near top of limestone knoll 0.66 mile (1.1 km.) west of Tsinan, Shantung, China (Eliot Blackwelder, 11-6-1903). *Obolus matinalis?. Eoorthis pagoda. Syntrophia orthia. IllEeniirus canens Walcott. 62667°— VOL 51, pt 1—12 19 lUaecurus sp. undt. Pterocephalia busiris Walcott. Ptychaspis ceto Walcott. Ptychaspis sp. undt. 290 CAJSIBEIAN BRACHIOPODA. CS6 (same horizon as C41, C49, and C54). Upper Cambrian: Lower part of Chaumitien limestone 25 feet below the top of Pagoda Hill [Blackwelder, 1907a, p. 42 (part of last list of fossils)], 1 mile (1.6 km.) west of Tsinan, Shantung, China (Eliot Blackwelder and Li San, 11-6-1903). *Obolus (Westonia) ep. undt, a. *Discinopsis? sulcatus. Acrotreta (dorsal valve resembling that of A. pacifica) *Eoorthis pagoda. *Syntrophia orthia. Scenella sp. undt. Walcott. Platyceras pagoda Walcott. Sb'aparollina rirce Walcott. Orthotheca sp. undt. Walcott. Cyrtoceras cambria Walcott. Menocephalus depressus Walcott. Pagodia bia Walcott. Pagodia lotos Walcott. Ptychaspis ceto Walcott. Conocephalina dryope (Walcott). Conocephalina belus (Walcott). Illsenurus dictys Walcott. Hysterolenus?. C57 (same horizon as C4, different section; below Cll, same section; above 058, same section). Middle Cambrian: In limestone nodules in the lower shale member of the Kiulung group [Blackwelder, 1907a, pp. 37 and 40 (first list of fossils)], 3 miles (4.8 km.) south of Kaokiapu and 4 miles (6.4 km.) north of Sintaihien, Sintai district. Shantung, China (?, 11-21-1903). *Acrothele rara. Orthotheca delphus Walcott. Agnostus chinensis Dames. Agnostus kushanensis Walcott. Dorypyge richthofeni Dames. C61 (about 25 feet above C6, same section; about same horizon aa Cll, different section; about 125 feet below C64, same section). Upper Cambrian: A dense black limestone in the uppermost limestone member of the Kiulung group [Blackwelder, 1907a, pp. 37 and 41 (third list of fossils), and fig. 10 (bed 13), p. 38], 3 miles (4.8 km.) southwest of Yenchuang, Sintai district, Shantung, China (Li San, 11-23-1903). Anomocare alcinoe Walcott. Anomocarella albion Walcott. Anomocarella chinensis Walcott. Dolichometopus deois Walcott. *BillLngsella pumpellyi. Ptychaspis baubo (Walcott) Proampyx burea Walcott. Pterocephalia busiris Walcott. Chuangia batia Walcott. Chuangia fragmenta Walcott. C62 (about 75 feet above CI, which occurs at a locality 3 miles east; about 75 feet below C12 and C13, same section). Middle Cambrian: Earthy layer in the middle limestone of the Kiulung group [Blackwelder, 1907a, pp. 37 and 40 (last. list of fossils), and fig. 10 (base of bed 7), p. 38], 2.5 miles (4 km.) south of Yenchuang, on the north-northeast spur of Hulushan, Sintai district. Shantung, China (Li San, 11-29-1903). *Obolus chinensis. I Hyolithes cybele Walcott. *Acrotreta shantungensis Walcott. | Anomocarella chinensis Walcott. C63 (about 40 feet above C5, same section; about 25 feet below C9, same section). Middle Cambrian: Sandy shale near the base of the Kiulung group [Blackwelder, 1907a, p. 37 (third paragraph), and fig. 8a (bed 32), p. 29], 3.5 miles (5.6 km.) southwest of Yenchuang, Sintai district. Shantung, China (Eliot Blackwelder, 11-27-1903). *Obolus obscurus. C64 (about 125 feet above C61, same section). Upper Cambrian: Upper limestone member of the Kiulung group [Blackwelder, 1907a, pp. 37 and 42 (first list of fossils), and fig. 10 (bed 20), p. 38], 2.7 miles (4.3 km.) south- west of Yenchuang, Sintai district, Shantung, China (Eliot Blackwelder, 11-25-1903). Lingulella damesi?. *Eoorthis doris. *Eoorthis kayseri. Eoorthis linnarssoni. *Huenella orientalis. Syntrophia orthia. Hyolithes daphnis Walcott. Orthotheca cyrene Walcott. Anomocare sp. Ptychaspis baubo (Walcott). Ptychaspis cacus Walcott. Ptychaspis callisto Walcott. Ptychaspis calyce Walcott. Ptychaspis ceto Walcott. Ptychaspis sp. Chuangia batia Walcott. Chuangia nais Walcott. Solenopleura beroe Walcott. Coosia bianos (Walcott). C67 (supposed to be from horizon of C36, C45, C47, C50, and C68). Upper Cambrian: Stream gravels taken from the wash from the mountains south of the city and used in making the railroad grade, 0.33 mile (0.5 km.) west of the west city gate at Tsinan, Shantung, China (Eliot Blackwelder, 10-15-1903). Obolus cf. matinalis. Eoorthis cf. linnarssoni. Ptychaspis sp. undt. Walcott. C68 (same horizon as C47 and C50, same section; below C36, same section; about same horizon as C45, different section). Upper Cambrian: Upper part of the Chaumitien limestone [Blackwelder, 1907a, p. 36 (part of third list of fossils)] on crest of ridge east of Chaumitien, 200 yards north of the wayside shrine, Changhia district. Shantung, China (Eliot Blackwelder, 10-25-1903). Acrotreta (dorsal valve resembling that of A. pacifica). Eoorthis kayseri. TERMINOLOGY. 291 C70 (35 feet below C69, same section). Middle Cambrian: Oolitic limestone about 30 feet above the base of the Kichou limestone [Willis and Blackwelder, 1907, p. 144, last list of fossils], 4 miles (6.4 km.) south-south- west of Tungyu, Shansi, China (Eliot Blackwelder, 2-21-1904). Obolus sp. undt. Scenella? dilatatus Walcott Stenotheca? simplex Walcott. Agraulos vicina Walcott. Inouyia capax (Walcott). Inouyia melie (Walcott). Conocephalina maia (Walcott). Conocephalina sp. C71 (about 50 feet below the horizon of C37 and C72, same section; about 125 feet above C75, different section). Middle Cambrian: Massive cliff -making limestone in the central portion of the Kichou formation [Willis and Blackwelder, 1907, pp. 139 and 145 (second list of fossils)], 4 miles (6.4 km.) southwest of Tungyu, Shansi, China (Bailey Willis and Eliot Blackwelder, 2-21-1904). Obolus shansiensis?. Acrotreta shantungensis. *Yorkia? orientalis. Eoorthis sp. undt. Orthotheca glabra Walcott. Agnostus chinensis Dames. Dorypyge richthofeni laevis Walcott. Anomocarella bigsbyi (Walcott). Anomocarella comus (Walcott). Anomocarella undata (Walcott). Solenoplem'a pauperata Walcott. Crepicephalus damia Walcott. C78 (about same horizon as C37, same section; about 50 feet above C71, same section; about 200 feet below C73, same section; about 225 feet below C74, same section). Middle Cambrian: Thin green-gray limestone interbedded with ocherous and green clay shales overlying the massive oolite in the Kichou formation [Willis and Blackwelder, 1907, pp. 139 and 145 (third list of fossils)], 4 miles (6.4 km.) east of Fanglanchon, Shansi, China (Eliot Blackwelder, 2-22-1904). Dorypj'ge richthofeni Isevis Walcott. Anomocare flava Walcott. Ptychoparia nereis Walcott. Conocephalina sp. undt. (Walcott). Obolus sp. imdt. *Lingulella (Lingulepis?) sp. undt, Platyceras willisi Walcott. Orthotheca glabra Walcott. C74 (about 225 feet above the horizon of C37 and C72, same section; about 25 feet above C73, same section). Upper Cambrian: A dense blue dolomitic limestone at the top of the Kichou limestone [Willis and Blackwelder 1907, pp. 139 and 145 (fifth list of fossils)], 4 miles (6.4 km.) east of Fanglanchon, Shansi, China (Eliot Blackwelder, 2-22-1904). Eoorthis kayseri. Ptychaspis bella Walcott. C75 (about 125 feet below C71, different sections), formation [Willis and Blackwelder, 1907, p. (Eliot Blackwelder, 2-13-1904). Obolus obscurus. *Eoorthis kichouensia. CoBcinocyathus elvira Walcott. Inouyia armatus (Walcott). Middle Cambrian: Limestone near the base of the Kichou 143], 4.5 miles (7.2 km.) south of Wutaihien, Shansi, China Inouyia melie (Walcott). Agraulos nitida Walcott. Agraulos uta Walcott. Ptychoparia lilia Walcott. ZOOLOGICAL DISCUSSION. The zoological relations of the Cambrian Brachiopoda, or their consideration from the paleozoologist's standpomt, are discussed under four general headings: (1) Characters of the shells, including the terminology adopted in describing them; (2) distribution in Cambrian strata; (3) evolution; and (4) classification. Under evolution no general description of the evolution of the Brachiopoda is attempted, nor is the life history of the living species treated. The discussion is limited to certain observations on the Cambrian species and genera that appear to add to our general knowledge of the subject. TERMINOLOGY. GENERAL STATEMENT. Except for the muscle scars of the inarticulate brachiopods, the terms used in the descrip- tion of genera and species are largely those defined by Schuchert [1897, pp. 73-75]. For the Atremata and Neotremata the terminology proposed by William King [1873, pp. 5 and 6] is adopted, and for the Protremata that used by Hall and Clarke [1892a, pp. 183-188] and given 292 CMIBKIAN BRACHIOPODA. under the terminology of Schuchert [1S97, pp. 73-77]. I agree with Hall and Clarke [1892c. p. 21] that the terminology of the English authors has claims for its adoption. F. Bloch- mann [1900, p. lOS] has proposed a set of terms for the muscles of the inarticulate brachiopods that has much to commend it. The terminology of Albany Hancock [1859, p. 800] has been extensively used by authors. The numbers in this correspond to the numbers given the termi- nology of King, Schuchert, and Bloclimann. Terminology of Hancock [1859, p. 800]. Inarticulates: Articulates: 1. Anterior occlusors. 1. Anterior occlusors. 2. Posterior occlusors. 2. Posterior occlusors. 3. Divaricator. 3. Accessory divaricators. 4. Central adjusters. 5. External adjusters. 6. Posterior adjusters. '6. Dorsal adjusters. 7. Peduncular. . 7. Peduncular. Terminology of King [1873, pp. 5-6]. 1. Anterior lateral. 4. Transmedians. 2. Centrals. 5. Outside laterals. 3. Umbonal. 6. Middle laterals. Terminology of Schuchert [1897, pp. 73-75]. 1. Retractors. 5. Protractors (externals). 2. Adductors. 6. Protractors (middles). 3. Pedicle. 7. Diductors. 4 1 '^ Ventral adjusters. 4. Rotators. Terminology of Blochmann [1900, p. 108]. 1. Lateralis. 4. Obliquus intemus. 2. Occlusor anterior. 5. Obliquus externus. 3. Occlusor posterior. 6. Obliquus medius. DEFINITIONS. Adductor muscles (see Central muscles). — The term adductor is used in the description of the muscles of the Protremata. Anterior lateral (retractor) muscles. — In the Atremata these extend from the outer lateral margins of the visceral area in the ventral valve to its anterior extremity in the dorsal valve, and serve to readjust the dorsal shell. Anterior region. — That portion of the shell in front of the transverse axis and opposite the pedicle opening. Apex. — The place of initial shell growth. It may be the most posterior portion of the valve or it may be situated near the transverse axis. Apical callosity. — The thickened boss at the inner side of the apex of the ventral valve of Acrotreta and other neotrematous genera, through which the pedicle tube or foramen passes. Area. — See Cardinal area. Articulate hracMopods. — In the orders Protremata and Telotremata the valves articulate by means of teeth and sockets. In some Atremata rudimentary articulation is also developed. (See p. 307.) Atremata. — Primitive inarticulate calcareophosphatic brachiopods with the pedicle emerg- ing more or less freely between the two valves. For a more detailed description see ' ' C'lassifi- cation of Cambrian Bracliiopoda," page 321. Brachia. — The fleshy, coiled or spiral, ciliated appendages of brachiopods serving in water circulation and respiration. Brachioccele. — All of the anterior half of the valves outside of the anterior portion of the parietal band. (After King.) Cardinal area.— A more or less well developed triangular area on each side of the delthy- rium, distinctly set off from the general surface of the shell. It is best developed on the ventral TERMINOLOGY. 293 valve of articulate bracliiopods, but is also present on the dorsal valve, and generally in a rudimentary condition in many inarticulate species. Wlien the area is rudimentary it is often called a false or pseudo-area (PI. II, figs. 1 and 7a; PL III, figs. 2a and 6b; PI. V, figs. Id at a; PL VI, figs. 1" and 3b). The area of some of the inarticulate genera is frecjuently divided by a line between the delthyrium and the outer margin; in such areas the line is caUed the flexure line, owing to the slight interniption in the striae of growth (PL VIII, fig. Id at f), and the spaces separated by the flexure line are called the inner and outer lateral spaces of the area. (See Deltidium and Foramen, and p. 303.) Cardinal extremities. — The terminations of the hinge liae. Cardinal muscle scar. — A large scar witliiu wliich the posterior, anteiior lateral, and transmedian muscles were attached. Cardinal process. — A variously modified apophysis situated posteriorly at the center of the hinge of the dorsal valve in articulate bracliiopods. To it are attached the diductor muscles, which by their contraction serve to open the valves anteriorly. (See p. 306.) Cardinal slopes. — The inclined surfaces extending from the umbonal slopes to the liinge margins. Central {adductor) muscles. — In the Protremata and Telotremata these muscles have their ventral insertion one on either side of the central axis, between the diductors. In passing to the dorsal valve they divide into four, and produce in that shell the two pairs of principal scars known as the anterior and posterior centrals. By contraction these muscles close the shell. In the Neotremata they are the essential muscles, the anterior centrals closing the valves, wlule the posterior pair serves to open the valves. In the Atremata there is a simple pair of centrals placed near the anterior extremity of the visceral area. CMlidium. — A dorsal plate, in appearance similar to the deltidium, covering the exterior portion of the cardinal pi'ocess in many Protremata. Its development does not begin until early neanic or later growth, and it is probably secreted by the dorsal mantle lobe. In the Atremata and Neotremata a similar plate, continuous with the dorsal cardinal region of the sheU, is named the pseudocliilidium. (See p. 306.) Crura. — Processes on the dorsal hinge plate of the Telotremata and some Protremata, to wliich are attached the fleshy bracliia and brachidia. These usually form the inner walls of the dental sockets, and may be supported by septal plates. Cruralium. — The dorsal equivalent of the ventral spondj^Hum. (See p. 309.) DeltJu/rium. — The triangular aperture transecting medially the ventral cardinal area, or the posterior surface from the apex to the posterior margin of the ventral valve, through some portion of wliich the pedicle passes. It has also been termed the fissure or foramen. The deltlwrium ma}' or may not be closed either by a calcareous deltidium or a phosphatic pseudo- deltidium. (See p. 305.) Deltidium. — A plate more or less continuous with the cardinal margin of the ventral \alve and covering the delthyrium in Atremata, Neotremata, and Protremata. Wlien present in inarticulate bracliiopods it is called the pseudodeltidium. In the Protremata, in wliich it is always more calcareous, tliicker, and more sharply defined, it is called the deltidium or the pseudochflidium. (See p. 305.) Dental plates. — Vertical plates supporting the teeth of the ventral valve in articulate bracliiopods. (See p. 310.) Dental soc]i:ets. — ExcaA^ations in the dorsal cardinal margin of articulate brachiopods, in which the teeth of the ventral valve articulate. The inner wall of the socket is elevated and forms the base of the crural plate. Diductor muscles. — In the Protremata and Telotremata the principal pair of diductor muscles has the larger end attached to the ventral valve near the anterior edge of the visceral area, and the other end has its insertion on the anterior portion of the cardinal process. By contraction these muscles open the valves. Dorsal valve. — Usually the smaller and imperforate valve and the one to which the brachia are always attached. Brachial, hsemal, socket, and entering valves are other terms more' rarely employed. 294 CAIVIBRIAN BRACHIOPODA. Efhebic. — Designating the mature shell. False area. — See Cardinal area. Flexure line. — See Cardinal area. Foramen. — A small circular passage through the deltidium, either below or at the apex of the ventral valve. Sometimes the foramen encroaches by pedicle abrasion on the umbo of the ventral valve. (See p. 314.) Foraminal tube. — The pedicle opening tlirough the ventral valve of neotrematous genera. (See PI. LVIII, fig. 5b.) Genital markings. — Radial markings or pits within the posterior portion of the visceral space, mdicating the position and extent of the genitals. Gerontic. — Designating old age. It is indicated in the ontogeny of vnaiiy species of brachio- pods by extreme thiclmess of the valves, obesity, or by numerous crowded growth lines near the anterior margin, a condition which sometimes produces truncation and absence of striae at the margin. (See p. 315.) Heart-shaped cavity. — Central depressed portion of visceral area (Mickwitz). (See PL VII, figs. 9, 11, and 12 at x; also figs. 1, 2, and 8.) Binge line. — The line along which articulation takes place. Also sometimes developed among inarticulate brachiopods. Inarticulate hracMopods. — In the orders Atremata and Neotremata the valves do not, as a rule, articulate by means of teeth and sockets, as is the case in the articulate orders Pro- tremata and Telotremata. Lateral areas. — That portion of the shell on each side of the central axis. Listrium. — In some Neotremata a plate closing the progressive track of the pedicle opening or pedicle cleft posterior to the apex of the ventral valve. (See p. 306.) Longitudinal axis. — A median line through the shell from the beak to the opposite margin. Median septum.. — An internal vertical plate commonly developed along the longitudinal axis and between the muscles of the ventral valve. Sometimes there is also a dorsal median septum. Lateral septa are rarely developed. Middle lateral muscle scar. — See Outside and middle lateral muscles. . Neanic. — Designating youthfuhiess, or the stage in which specific characters begui to develop. Neotremata. — Circular or oval, more or less cone shaped, inarticulate calcareophosphatic brachiopods with the pedicle opening restricted throughout life to the ventral valve. For a more detailed description see "Classification of Cambrian Brachiopoda," page 323. Nepionic. — Designating the smooth shell stage succeeding the protegulum. Outside and middle lateral (protractor) muscles.— In the Obohdse one pair has the ventral ends fastened at the anterior extremity of the visceral area, extending backward and inserted near the lateral margin of the dorsal valve, outside the transmedians. A second pair originates just behind the centrals of the ventral valve and is inserted posterior to the first pah. These muscles draw the dorsal valve forward. Parietal band.— The point of attachment of the muscular wall surrounding the visceral area. Pedicle.— The flexible muscular organ of the ventral valve by means of which brachiopods may be attached to extraneous objects. Pedicle furrow.— The external furrow adjoining the foramen or pedicle opening in certain neotrematous genera. (See PL LXXXIII, figs. 1 and 2 ; PL LXXXIV, figs. 1 and 5c.) Pedicle groove.— The median groove on the cardinal areas of the valves, formed by the pedicle extending through the posterior margin of the valves when they were closed. Pedicle muscles.— In the Protremata and Telotremata one pah originates on the ventral valve at points just outside and behind the diductors and another on the dorsal valve behind the posterior centrals, while the opposite ends of both are attached to the pedicle. Besides these there is an unpaired muscle lying at the base of the pedicle, attaching it closely to the ventral valve. TERMINOLOGY. 295 Pedicle opening. — See Delthyrium. Pedicle tube. — See Foraminal tube. Platform. — An internal median thickening of the shell elevating the muscles. Seen in cer- tain families of the Atremata and more rarely in the Neotremata. (See Spondyhum and pp. 307 and 309.) Pleurocceles. — Areas between the parietal band and the outer posterolateral margins. (After King.) Posterior region. — That portion of the shell back of the transverse axis and toward the beak or apex. Protegulum. — The initial shell of brachiopods. It is smooth and of microscopic size, in outline being semicircular or arcuate and without cardinal areas. Protractor muscles. — See Outside and middle lateral muscles. Protremata. — Articulate calcareous brachiopods with the pedicle opening restricted to the ventral valve throughout life or during early growth. Pedicle aperture modified by the del- tidium. Brachia unsupported by a calcareous skeleton but nearty always b}^ a crura of variable length. For a more detailed description see ' ' Classification of Cambrian Brachiop- oda," page 325. Pseudo-area. — See Cardinal area. PseudocJiilidium. — See Chihdium. Pseudocruralium. — Dorsal equivalent of pseudospondylium. P'seudodeltidium. — The convex medial portion continuous with the ventral cardinal areas in Atremata and Neotremata. (See Deltidium.) Pseudqpedicle groove. — See Pedicle groove. Pseudosfondylium. — See Spondylium. Retractor muscles. — See Anterior lateral muscles. Septal -plates. — Plates supporting the crural processes, alsoloiown a.s crural plates. (See p. 310.) Sessile spondylium = Pseudospondylium. Splanchnocatle. — The area within the parietal band. (After Eing.) Spondylium. — A plate in some articulate brachiopods, mainly the Pentameracea, formed by the union of converging dental plates, to the upper surface of which are attached the adduc- tor, diductor, and pedicle muscles. The spondylium mny rest upon the ventral valve or may be supported by a median septum. The spond3^1ium appears to be first indicated in the artic- ulates by a thickening of the shell of the ventral valve beneath the umbonal region so as to form an area upon which all the muscles of the valve have their points of attachment. In Billingsella this is beautifully illustrated by B. exporrecta (PI. LXXXVIII, figs. Id, le, and 2a) and B. plicatella (PL LXXXVI, figs. 3i, 3k, and 3m). In its development the spondylium is fore- shadowed in the Atremata by the so-called platform of ElJcania (PI. LI, figs. 1 and la) and bj^ the still more primitive form in Ololus (PI. VI). For the purpose of reference the rudimentary spon- dylia attached directly to the inner surface of the valve, as in iJiZZmgrse/IZa, may be called pseudo- spondylia (sessile spondyUa, Ulrich) , and those free or supported by a septum or septa, spondylia. In the Atremata the homologous equivalent has been known as the platform. In Obolus, Elkania, etc., there is sometimes developed in the dorsal valve a plate similar in appearance to the spondj'lium, but different in origin; this is known as the crurahum. (See p. 307.) Teeth. — Two processes of the ventral valve of articulate brachiopods, serving for articula- tion. (See p. 307.) Telotremata. — Articulate Brachiopoda with the pedicle opening shared by both valves in nepionic and early neanic stages, usually confined to one valve in later stages, and becoming more or less modified by deltidial plates in ephebic stages. Bracliia supported by calcareous crura, loops, or spiraha. Prodeltidium absent. (After Schuchert.) Transmedian (rotator) muscles. — In the Obolacea these are situated posteriorly just in advance of the umbonal muscle, two on one side and one on the other. By their contraction the dorsal valve turns alternately, first in one direction and then in the other. Transverse axis. — A line through the shell from right to left midway between the beak and anterior margin. (See Longitudinal axis.) 296 CAMBRIAN BRACHIOPODA. Trapezoidal area. — The area on each side of the heart-shaped cavity in Oholus in which the outside and middle lateral scars and central muscle scars were attached. (See PI. VII, figs. 10 and 12.) Umho. — The elevated or prominent portion of the valve anterior to the apex. Umbonal cavity. — The hollow space in the interior of the shell beneath the umbo. Vmbonal muscle. — A single muscle situated in the umbonal region of most Atremata. By its contraction the valves are opened anteriorly. In Oholus this muscle divides toward the ventral valve. Umbonal slopes. — The inclined surfaces about the umbo and opposite the cardinal slopes. Vascular (pallial) sinuses. — Two convergent or divergent primary sinuses of the circulatory S3'stem, traversing the mantle and originating in the posterior medial region. They usually have numerous secondary (lateral and peripheral) branches, and both often leave impressions in the shell. (See p. 311.) Ventral valve. — Usually the larger valve situated on the ventral side of the animal. Among articulate brachiopods the valve is usually easily distinguished by the presence of a delthyrium or pedicle opening through which the pedicle is protruded. In many atrematous genera the ventral valve is not readily distinguished. When the shell is cemented to foreign bodies it is always by the ventral valve. It is usually the larger and deeper of the two valves. Pedicle, larger, dental, neural, and receiving valves are synonymous terms. Visceral area. — The posterior region of the interior of the valves between the palhal sinuses; in general the immediate area of the median muscle tracks. Visceral cavity. — Visceral area. THE BRACHIOPOD SHELL. STRUCTURE. GENERAL STATEMENT. The general structural characters of the shell of the Ordovician and later brachiopods have been so fully described by authors that it does not appear to be necessary or desirable to repeat them. The student will find a full description given by Hall and Clarke in their "Introduction to the study of the Brachiopoda" [1892a, pp. 150-225]. Some of the more important works that contain data on the structure of the shell are those of Hancock,"^ King,*" Carpenter," Davidson/ and Mickwitz.^ The greater proportion of the Cambrian brachiopods are largely corneous or chitinous. These are restricted to the inarticulates, but the inarticulates of the Cambrian do not all pos- sess corneous shells. Mckwitz has shown [1896, pp. 102-142] that the shells of Oholus and its subgenera are essentially the same as those of Lingula in composition and structure. In both the shells are composed of successive calcareous and corneous lamellse that vary in thickness and structure. The calcareous lamellse are prismatic and crossed by minute tubules; the corneous lamellae are compact and imperforate. Hall and Clarke [1892a, p. 175], in speaking of the shells of the articulate brachiopods, say: Among the articulate genera, under favorable preservation, there may be distinguished three distinct calcareous shell layers; an inner prismatic or fibrous layer, which constitutes the greater portion of the shell; above this is a thin lamellar layer, and the outer surface of the shell is covered by a tenuous epidermal film or periostracum. When the shell is punctate the tubules open on the inner surface in narrow apertures, whence they widen upward, abruptly expanding in the lamellar layer, at whose upper margin they terminate. They do not pierce the periostracum. a Hancock, A., On the organization of the Brachiopoda, 1S59, pp. 791-869. b King, W., On some characters of Lingula anaiina, 1873, pp. 1-17. t Carpenter, W. B., On the intimate structure of the shells of Brachiopoda, 1853, pp. 23-45. d Davidson, T., On the classification of the Brachiopoda, 1853, pp. 41-136. « Miclrwitz, A., Ueber die Brachiopodengattung Obolus, 1896. THE BRACHIOPOD SHELL. 297 Among the calcareous, inarticulate brachiopods the shell of the Cambrian genus OholeUa shows a dense, compact, slightly lamellated structure made up of a granular groundmass pierced by extremely small tubules or pores. The substance of the shells of Rustella and Yorlcia is unknown, but from the character of the casts and the fact that the corneous shells of Micromitra in the same matrix are preserved it is probable that it was calcareous. The shells of Quehecia, Trematobolus, and Dearbornia are also calcareous. In Kutorgina and Schuchertina, forms that may be referred to either articulate or inarticu- late genera, the shells appear to be calcareous, compact, and without fibrous structure. Hall and Clarke, when speaking [1892a, p. 174] of the composition of the shell of the fossil hnguioids, say: In the group of fossil linguloids, begimung with I/ingula, passing through Lingulops and Lingulasma to Trimerella and its allies, there is a regular increase in the relative amount of calcareous matter in the shell, so that the Trimerellas, which are large and ponderous shells, seem to have wholly lost their corneous matter. The predominance of corneous or calcareous shell matter does not appear to be of more than generic importance in the classification of the brachiopods.. It is true that the knowm articulate genera are all calcareous, but it is equally true that among the inarticulate group calca- reous shells occur. Alteration, replacement, and removal of original shell substance have changed the shell of so many species that other characters must be depended on for classification. MICROSCOPIC STRUCTURE. In previous work on the Cambrian Brachiopoda, except in the cases above cited, practically no attention was paid to the riiicroscopic shell structure. The importance of this feature in the classification of later species suggested the possible value of a microscopic study of the earlier forms, and at my request Mr. E. 0. Ulrich and Mr. R. S. Bassler prepared thin sections and also assisted in the preparation of figures 1-15 (pp. 298 and 299) and in the preHminary study of the sections. The preparation of thin sections of these earty brachiopods is accompanied with difficulties which, together with the lack of sufficiently extensive collections, have undoubtedly prevented previous study along the same line. Specimens suitable for sectionmg, especially of the cal- careous forms, are not at all common, and when they do occur they are almost invariably buried in the rock and are so thin that the parting of the inclosmg matrix does not leave sufficient shell substance for the preparation of sections. In the present work the specific identity of a shell was first determined by uncovering about one-half the valve, and the other half, still embedded in the matrix, was then used m making the section. The structural features are often restricted to individual lamellse and the right zone for microscopic examuiation was deter- mined simply by close observation as grindmg proceeded. Both vertical and tangential sec- tions were prepared, the former cutting the shell at right angles and the latter cutting the shell in planes more or less parallel to the layers or lamellae of which it is composed. The most inter- esting results were obtained from the tangential sections, as the thin shells showed little decided structure in vertical sections. 298 CAMBRIAN BRACHIOPODA. Description of figures l-15aA Billingsella plicateUa Walcott [1905a, p. 240]: Figure 1. — Diagi-ammatic sketch of a small portion of a tangential section, X 200. The granular groundmass, \vith small pores and tubules 4 or 5 times their own diameter distant from each other, is also typical of other members of the Billingsellidse. Upper Cambrian, Gallatin Valley, Montana. Dalmanella subequata (Com-ad) [1843, p. 333]: Figure 2. — Photograph of a tangential section, X 35, showing the fibrous structure and comparatively large pores. Ordovician, St. Paul, Minnesota. Kutorgina cingulata (Billings) [1861b, p. 8]: Figure 3. — ^A small portion of the tangential section shown in fig. 8, X 200. The minute structure of this and the following species is essentially the same as that shown in fig. 5, the only difference being the closer aiTangement of the pores. Lower Cambrian, Swanton, Vermont. Obolus apollinis Eichwald [1829, p. 274]: Figure 4. — Small portion of tangential section, X 200. The minutely porous granular structure is beautifully shown in this species, in which the pores are arranged more closely than in any other observed. Upper Cambrian, Obolus sandstone, Esthonia, Russia. Billingsella coloradoensis (Shumard) [1860, p. 627]: Figure 5. — Photograph of horizontal thin section enlarged fifty diameters. This shows the characteristic granular groundmass of the Cambrian Billingsellidse. Upper Cambrian, Morgan Creek, Burnet County, Texas. Nisusia fe^inata (Billings) [1861b, p. 10]: Figure 6. — PhotogTaph of horizontal thin section enlarged fifty diameters. This section shows a granulai ground- mass in which faint indications of small pores or tubules may be seen with a high power. Lower Cambrian, ■ 2 miles east of Swanton, Vermont. Soorthis remnicha (N. H. Winchell) [1886, p. 317]: Figure 7. — Photograph of horizontal thin section enlarged fifty diameters. This section shows the same type of groundmass as that illustrated by fig. 6. Upper Cambrian, Cold Creek Canyon, Bm-net County, Texas. Kutorgina cingulata (Billings) [1861b, p. 8]: Figure 8. — Photograph of horizontal thin section showing granular shell substance. There are few slight indi- cations of pores. Lower Cambrian, Swanton, Vermont. Dalmanella multisecta (Meek) [1873, p. 112]: Figure 9. — Horizontal thin section enlai-ged fifty diameters. This siiows the fibrous structure of the shell pene- trated by numerous fine tubules. Ordovician, Eden shale, Cincinnati, Ohio. Dalmanella parva (de Verneuil) [1845, p. 188]: Figure 10. — Horizontal thin section showing fibrous structm'e; also section of the tubules that penetrate through the shell. Middle Ordo^dcian of Russia. Syntrophia lateralis (Whitfield) [1886, p. 303]: Figure 11. — Horizontal thin section enlarged fifty diameters, showing the arrangement of the pores in lines that radiate from the apex toward the margin. Lower Ordovician, Beekmantown, Fort Cassin, Vermont. Plectorthis plicateUa (Hall) [1847, p. 122]: Figure 12. — Horizontal thin section enlarged fifty diameters. This section shows the fibrous structure so characteristic of the Ordovician orthoids. Ordovician "Lorraine shaly limestone," Cincinnati, Ohio. Euenella abnormis (Walcott) [1905, p. 289]: Figure 13. — Horizontal thin section enlarged fifty diameters. The pores in this genus are smaller than in Syntrophia, but their arrangement is essentially the same and shows the line effect characteristic of the Pentameracea. Upper Cambrian, Gallatin Valley, Montana. Obolella crassa (Hall) [1847, p. 290]: Figure 14. — Horizontal thin section enlarged fifty diameters. This shows the fine granular groundmass, with an indication in the upper left side of the section that a surface ornamentation has been cut across. Lower Cambrian, Bic, Canada. Obolus apollinis Eichwald [1829, p. 274]: Figuees 15 and 15a. — Transverse vertical thin sections enlarged so as to show the lamellae and the presence of a large tubule that appears to have more or less imperfectly penetrated through the shell. Upper Cambrian, Obolus sandstone, Russia. o Figs. 1-4 are copied from flgs. 2-5 on p. 151 of a preliminary paper on the classification of the Cambrian Brachiopoda [Walcott, 1908e]. Figs. S-15 and 15a are copied from flgs. 1-12, PI. XII, of the same paper. THE BRACHIOPOD SHELL. 299 ■^-V .5* ■" 6 O 0 o o - o o ^J o & M e o o a a t) o -o e a o 0 !»' ." 0 ':' o o => O 0 ■. •= o ■■* ■ o O, ©1 -o' o 0 5 D O .°. a o "';--;' ', ■-": W* yj^v -' .■-■■.■ , ■ :' . P :i^w^' >^'''' ■ ' ■ "■'" . ■- ' '' ^pr^ ic I ■^ "^ ' ■ . . , / S" -1'' #^ >;'■''■'■'■ K -f , ,?'■:«:-,'' ■. ■,' >:' 300 CAMBRIAN BRACHIOPODA. The general resemblance of tlie Cambrian eoorthoids to certain Ordovician Protremata is so strikincj and the lines of descent so suggestive that particular attention was devoted to this group. Exammation, however, brought out the fact that this apparent relationship disapj)ears when the shell structure of the two groups is compared. Sections of the shells of members of the Bihrngsellidfe, of which figure 1 is typical, all show a lamellar structure Avith indications of more or less numerous, scattered, very minute pores or tubules passing without interruption through one lamella. In some sections the spots indicating the tubules are arranged in rows radiating from the beak of the shell to the margins, but no other regular arrangement can be seen. The great mass of the shell is made up of a compact, finely granular base A\itli dark spots and occasional minute crystals of calcite, a groundmass which, under the microscope, appears very much like that of a fine argillaceous shale. The Ordovician Protremata have a clearer, more crystalline aspect or color than the Cam- brian BillingsellidsB, a dMerence which probably indicates either a purer lime composition for the former or more probably a higher percentage of calcium phosphate for the latter. In chemical aspect the shells of the Billings elhdse appear to resemble those of the Atremata and Neotremata more closely than do the Orthidge. (Compare figs. 1, 3, and 4 with 2.) Analyses of the respective shells would be necessary to prove these relations, but they are interesting subjects for investigation in view of the possible derivation of the Billingsellidse from the Atremata. In the Cambrian articulate genera, with the possible exception of SyntropMa and liuenella, the minute, fibrous structure so characteristic of most if not all orthoids is entirely absent. (Compare figs. 1 and 2.) SyntropMa and Huenella, however, greatly resemble each other. Thus sections of the shell of Huenella ahnormis of the Upper Cambrian (fig. 13) and Syntropliia lateralis of the Lower Ordovician (fig. 1 1 ) show the same radial arrangement of the pores seen in the Billingsellidfe, but the shell structure is fibrous and the rows are coincident in direction with the fibers. On closer study this apparently fibrous structure can be resolved into more or less parallel bands or walls of shell substance separating rows of closely arranged, rectangular, porehke spaces. These spaces may be seen distinctly in thick sections, but they disappear when the section is made sufficiently thin to give a clear image under very high power. Sections of the linguloid genera were also prepared and studied, but the thinness of the shells and their phosphatic character prevented very satisfactory results. The irregular large tubules men- tioned by ]\Iickwitz [1896, p. 106] are beautifully shown in sections of Oholus apollinis before me. Some of the tubules penetrate several lamellfe of the shell and suggest the tubules of some of the orthoids. (See figs. 15 and 15a.) The same general structure, with the exception of the larger tubules, appears to be characteristic of all of the corneous shells of the Atremata and Neotremata, and, so far as known to me, of all of the Cambrian corneous shells. Figures 5-14 are from photographs which have not been retouched, so that personal equa- tion may be eliminated. Unfortunately, higher magnifications could not be used without a loss of clearness, but even at the present magnification these views show decided differences in structure. In conclusion, it appears that the Cambrian Billingsellidse are further removed from the Ordovician and later Protremata than has hitherto been suspected, the microscopic shell struc- ture in the former being of granular material pierced by small pores and in the latter of fibrous material. On the other hand, the microscopic structure of the Cambrian and later Pentameracea is so similar that an unbroken line of descent is indicated. SURFACE ORNAMENTATION. GENERAL STATEMENT. The known protegulum of all brachiopods is smooth, and the shells have usually advanced well into the nepionic stage of growth before the outer surface is ornamented to any considerable degree. Many species of Cambrian inarticulate brachiopods (especially the Obolacea) remain smooth through all stages of growth, with the exception of Hues and varices of growth. Many of tliem, however, have some form of ornamentation, and some of the most ornate types of surface, THE BEACHIOPOD SHELL. 301 such as that of Micromitra (IphideUa) pannula (PL IV) and Botsfordia cxiata (PI. LIX), were fully developed in Lower Cambrian time. I have given much attention to the question of the value of surface ornamentation for the purposes of systematic classification among the Cambrian brachiopods, and have concluded that only in cases where a cUstinctive surface is persistent for a considerable period can it be considered of more than specific value. In one instance I have given the type of surface found on Obolus (Westonia) aurora (PI. XL VI, fig. Ih) a subgeneric value, but its wide range of varia- tion makes me doubtful of its utility. ATREMATA. So far as known, the outer surface of Rustella, the most primitive type of brachiopod known (PL I, figs. 1, la-e), is marked only by concentric growth lines. Among other genera referred to the Paterinidse, VolhortTiia (PL I, figs. 6, 6a-e) has only concentric growth lines on the outer surface, although it has numerous radiating lines on the inner laminations of the shell.' On the outer surface in the genera Mickwitzia (PL VI) and Ilelmersenia (PL LXIII, figs. 7, 7a, and 7e) are found concentric and racUating lines and small tubercles (apparently rudimentary spines) that are ornamental in their arrangement and effect, but it is in Micromitra that the greatest variety and most lughly ornamented surfaces appear. Species that have a simple type of surface, marked only by concentric fines of growth, are grouped under the subgenus Paterina (PL II), while those having an ornate surface (PL IV) are included in the subgenus IpTiidella. Transition forms, intermediate in surface ornamentation between the two extreme types, are referred to Micromitra, since the type species, M. sculptilis, has this intermediate form of surface. The species Micromitra {Paterina) pealei (PL III, figs. 3, 3a-e) approaches closely to Micromitra sculptilis (PL III, figs. 5, 5a, and 5e) but is not quite so highly ornamented. Micro- mitra (IphideUa) pannula and its varieties (PL IV) have a highly ornate surface, and the species has both Avide geographic distribution and stratigraphic range. It is abundant in the Middle Cambrian and it also occurs in the upper portion of the Lower Cambrian section in Nevada. The oldest known bracluopod from British Columbia, Micromitra {IpTiidella) louise, which occurs 3,090 feet down in the Lower Cambrian terrane, has an ornamented surface much like that of M. {I.) nyssa (PL III, fig. 9), winch occurs at the summit of the Lower Cambrian in the same stratigraphic section. None of the Obofidffi of the Lower Cambrian is known to have an ornamented surface, but in the Middle Cambrian many species show, in addition to the concentric strise and lines of growth and the radiating strise and ridges, a variously pitted and granulated surface primarily formed by the crossing of the radiating and concentric ridges by oblique vmdulating ridges. Wlaat I have called the Westonia type of surface (Pis. XL VI and XLVII) is the most common. A variety of this type where the lines are transverse is more rarely seen (PL XLIX, fig. If and Ig). The Westonia surface is not confined to Oholus (Westonia), as it occurs among the Neotremata in the genera Oholella {Glyptias), Botsfordia, Acrotliele, Acroireia, and Acrothyra. (See description of Oholus {Westonia), p. 450.) It is also present on Ordovician and later brachio- pods and it is known on Lucinia divaricator and other pelecjrpods. [See Winchell and Schuchert, 1895, pp. 345-346.] In Oholus {Acritis) (PL XIII, fig. 3) the irregular, undulating, and more or less inosculating concentric ridges suggest one of the rudimentary characters of some t,ypes of the Westonia surface, but their origin was probably different. The surface of Lingula cincta Barrande [1879b, PL CV, figs. lA, 2A, and 2f], from Etage E (Ordovician), is much like that of Oholus (Acritis) anti- quissimus, but it is probably an illustration of the persistence of a form of surface sculptiu-e through several geologic form.ations and a corresponding period of time. The surface of Lingula eximia Barrande [1879b, PL CV, block 1] is highty ornate. The figure is introduced on Plate XXXII, fig. 3, as a possible type that may be found to have existed in late Cambrian time. Oholus (Mickwitzella) siluricus (PL XV, figs, lb and Ic) has fine crenula- tions on the front side of certain concentric ridges, a type of ornamentation that is unknown among the Cambrian bracliiopods except in this one Upper Cambrian species. 302 CMffiRIAN BRACHIOPODA. The presence of spines in inarticulate genera is of rare occurrence. The oldest known intlication of theii- presence in other families than the Paterinidse is on Bicia gemma (PI. L, fig. la) and Nisusia festinata (PI. C, fig. 1) of the Lower Cambrian. The Middle Cambrian Nisusia alberta (PI. C, fig. 3c) has a series of strong spines, and, in the Upper Cambrian, Acrotreta spinosa (PI. LXXIX, figs. 4a, ih, and 4g), Schizamhon (PI. LXXXIV, figs. Id and 3a), and Helmersenia ladogensis (PI. LXIII, fig. 7e) appear to have had a spinose surface. NEOTREMATA. OholeUa (Pis. lAV and LV) has, so far as known to me, only concentric lines and ridges of growth, but the surface of Botsfordia is usually quite ornate. The granular type is best shown b}- B. granulata (PI. LVII, fig. 4r) and B. csdata (PI. LIX, figs. Ih and lo), and the pitted or reticulated type, formed by the crossing of obliquely concentric ridges, by B. pulchra (PI. LXII, figs. 5, 5a-f, and 5k). Botsfordia? harrandei (PI. LVII, figs. 7, 7a, and 7b) appears to have a smooth surface or one marked only by concentric growth lines. Trematoholus of the Siphonotretidse is like OholeUa in having a plain surface, but in Yorlcia orientalis (PI. LXXXII, fig. 3a) the surface is of the reticulated tj^pe and resembles that of Micromitra (Iphidella) pannula of the Atremata. SipTionotreta has a finely granulated surface (PI. LXXXI, figs. 6 and 6a), also a pustulose surface (PI. LXXXI, figs. 5 and 5a). The latter type is found in the Atremata in Mickwitzia (PI. VI, fig. 2) and the granulated surface is present in Botsfordia (PI. LVII, fig. 4r) of the Obolelhdffi. The surface of Schizambon (PI. LXXXIV, figs. Id and 3a) difl^ers from all other genera of the Neotremata excent Acrotreta (PI. LXXIX. fig. 4g) in being spinose. The surface of Acrothele varies in almost the same manner as that of Micromitra. Species occur mth only concentric growth lines, as in AcrotTiele subsidua (PI. LX, figs. Ic, Id, and li), or the same species may have a few radiating ridges (PI. LX, figs, la, lb, and 8). The radiating ridges may be characteristic of some forms of the adult shells of the species, as in ^ . matthewi multicostata (PI. LXI, figs. 5, 5a-c). In addition to these, there may be an irregular more or less inosculating series of fine concentric ridges, as in A. avia (PI. LXII, fig. Ij); a finely granular surface, as in A. coriacea (PL LVI, fig. Ig) ; a more distinctly and strongly granular surface, as in A. {Redlichella) granulata (PI. LVI, fig. 2g) or A. prima costata (PI. LXI, fig. 4d). A pitted surface is sometimes formed by the crossing of obliquely concentric narrow ridges, as in A. beUa- punctata (PI. LVII, fig. 3b)." Only a few species of Acrotreta have more than the smooth surface with concentric lines. I was greatly surprised when I found a shell showing a spinose surface, A. spinosa (PI. LXXIX, figs. 4a, 4b, and 4g), and again when I found a reticulated surface, A J canceUaia (Pi. LXXIX, fig. 5a). Both species are from the fauna of the Cordilleran sea; A. spinosa developed in late Cambrian time and AJ cancellata in early Ordovician time. The closely related genus Acrothyra has a very fine Westonia type of surface (PI. XL VII) that can be seen only with the aid of a strong lens. PKOTKEMATA. The ornamentation of the surface of the shells of Protremata is usually in the form of radiating strise, fines, and ridges of varying size and number, with concentric lines and ridges of growth. The racUating striae, lines, and incipient ridges or plications are usually first seen on the inner laminations of the shell, and often this occurs in species that do not show it on the outer surface of the shell. Tlfis is beautifully sho^vm in the atrematous genera MicTcwitzia (PI. VI, figs. Ik and 1 1), Obolus (PI. VIII, figs, li and 2; PI. X, figs. 2 and 2&\Oholus {Westonia) (PI. XII, figs. 7 and 7c; PI. XLVII, figs, la, Ig, and Im), Obolus {Lingulobolus) (PL XVI, figs. 1, lb, 2c, 2f, 2h, and 2i), Lingulella (PL XVII, fig.ll; PL XXXI, figs. 6e and 6g; PL XXXVIII, figs. 2d and 2f), Lingulella {Lingulepis) (PL XLI, figs, la-c, If-h, and Ij-m), and Dicellomus (PL LII, figs. 2c and 2h; PL LIII, figs, lb, Ic, 2, 2a, 4a, 4d, and 4e). In Bicia gemmxi (PL L) the radiating lines and ridges occur on both the interior and exterior surfaces, and there are also elongated tubercles that suggest fine spines. In Kutorgina granulata (PL V, figs. 5b and 5c) THE BRACHIOPOD SHELL. 303 they are strong on the inner surface and less marked on the outer surface. Other species of Kutorgina (PI. V) have a smooth, or only concentrically lined, surface. Schuchertina cambria (PI. LI, figs. 6, 6a-m) has a fine series of internal radiating stride and ridges, but the exterior surface is without them. Among the Protremata the radiating ridges are present in most genera, although some species of a genus may not have them. In the Billingsellinse a few species with smooth shells occur (PI. LXXXVII, figs. 1, la-e, 7, 7a, 5, and 5a), but the greater number have both interior and exterior radiating ridges (Pis. LXXXVII-XC). Among the Nisusiinae and Eoorthinse all the species show more or less of external radiating lines and ridges; sometimes the young shells are nearly smooth (PL XCVIII, figs. If, 2b, and 5), but this in most cases is at a very young stage of growth. The Syntrophiidse show variation from the smooth adult shells of SyntropJiia calcifera (PL CIV, figs. 1, la-i) to the strongly costate shells of Huenella texana (PI. CHI, fig. le). Swantonia (PL CIV, figs. 5 and 6) has numerous radiating costse. INTERLOCKING PLICATIONS. Interlocking of the margins of the valves began as soon as phcations or ribs first appeared on the shell. The wide variation in size and number in the same species (PL CIII, figs. 1, la-g) indicates that this character is, like that of surface ornamentation, of little more than specific value. In the description of the surface ornamentation of the Protremata (p. 302) reference is made to the order of appearance and the character of the ridges or plications among the Cambrian brachiopods. CARDINAL AREA. ATREMATA. In the protegulum stage of the atrematous shells the posterior margins of the valve are not bent regularly inward toward each other and there are no indications on the surface of a cardinal area. There is a simple cleft, the length of which is dependent on the degree of round- ing of the posterior margins. Among the genera and species referred to the order Atremata, the pseudodeltidium of Rustella edsoni (PL I, figs, lb, Ic, le) is extremely rudimentary, if devel- oped at all, and there is no trace of a thickened cardinal surface. The pedicle appears to have impressed itself on the shell to the extent of making a shallow furrow on the posterior inner margin of the rather thick shell of the two valves. In MicJcwitzia monilifera (PL "^"1, fig. 1") the pressure and movement of the pedicle against the vertical cardinal margin during the growth of the shell have had the effect of bulging it outward so as to produce a pseudodeltid- ium, but on neither of the valves is there a trace of a cardinal thickening. In Ilelmersenia lado- gensis (PL LXIII, fig. 7d) a pseudodeltidium similar to that in Mickwitzia occurs on the ventral valve, and here also there is onl_y a thickening of the posterior margin and not a true cardinal area. In the genus Micromitra the mechanical influence of the pressure of the pedicle on the ventral valve is much more pronounced; in Micromitra (Paterina) bella (PL II, figs, la and lb) the pseudodeltidium is more clearty defined than in Mickwitzia or Helmersenia, and the concave arch of the cardinal margin for the protrusion of the pedicle is greater. In Micromitra {Paterina) superha (PL II, fig. 7) the excavation of the pseudodeltidium has increased, and in Micromitra (Paterina) logani (PL II, fig. 6b) and Micromitra (Iphidella) pannula (PL IV, figs. Id, 2a", and 2b') the pseudodeltidium has been excavated to such an extent that there is nearly an open delthyrium. This difl^erence in delthyrial openings must be due to variation in the thickness of the pedicle. Attention is called to the pseudodeltidium sho^\^l m figure 2a", Plate IV, where the tripartite, longitudinal division recalls the pseudodeltidium of Acrotreta nicTiolsoni (PL LXXIII, figs. Ig and Ih). So far as known to me, no true cardinal area is present in any species of the Paterinidse, though there may be a more or less marked thickening or bulging of the posterior margin of the valves to form a pseudodeltidium. In the Obolidse the vertical cardinal area is present in aU known species, but in varying degree of development. It is shghtly shown in Delgadella (PL XXIX, figs. 5, 5a, and 5b) and well defined in Obelus prindlei (PL XXVII, figs. 3a, 3b, 3c, and 3e), Lingulella granvillensis 304 CMIBRIAN BRACHIOPODA. (PI. XXII, figs. 1 and lb), Lingulella naihorsti (PI. XXXI, figs. 1 and la), and lAngulella scJiu- clierti (PI. XXI, fig. 6), all of which are from the Lower Cambrian. Lingulella schuclierti is probably the oldest known species, unless it be Delgadella lusitanica. In Dicellomus the cardinal area of the ventral valve (PI. LII, figs. Ic and Id) is not unlike that of Oholus, except that short teeth (PI. LII, fig. Id) appear to have been developed, and that on the cardinal area of the dorsal valve (PI. LII, fig. li) there is a socket-like groove on each side for the reception of the projection in the ventral valve. On other specimens of the area of the dorsal valve there are many minor depressions or crenulations (PI. LII, fig. Ij), but no defined groove or socket. On the dorsal valve of another species the cardinal area (PI. LIII, fig. 1) is not unlike that of the dorsal valve of Oholus. There is considerable variation in the details of form and size of the vertical cardinal areas of the various species of Oholus, its subgenera, and Lingulella, but it is all within the tj^pical Oholus-like cardinal area as seen in Oholus afoUinis (PI. VII). A curious individual development or extension of the area is shown in some specimens of Oholus namouna (PI. VIII, fig. 2a) and 0. rhea (PI. IX, fig. 1), where the posterior margin of the mantle appears to have been drawn farther forward inwardly and a thin deposit of shell made, so as to carry the front m,argin of the cardinal area far in advance of its usual position in the species of the genus. On Bicia, one of the oldest genera (PI. L), the area is as strongly defined as it is in Oholus and its subgenera, and teeth or articulate processes are suggested. In ETkania (PI. LI, figs. 1 and la) the cardinal area so merges into the thickened platform that it is not readily separable from it. I have referred to this as the internal cardinal area, or the area that is inclined inward from the plane of the margins of the valves and united by shell deposit to the interior of the shell. In Neoholus the internal cardinal area of the dorsal valve extends forward as a semicircular shelf (PI. I, fig. 4b). It is a modified cardinal area on the plane of the margins of the valves, but in the adult it does not extend over the rounded posterior margin of the valve. The area of the ventral valve is unknown, but from the presence of an open delthyrium (PL I, fig. 4') it is not probable that a well-defined cardinal area exists. In the dorsal valve of Lingulella granvillensis (PI. XXII, fig. Id), Lingulella helena (PI. XXIV, fig. 3c), Oholus (Westonia) euglyphus (PI. XL VIII, fig. le) there is a strong undercut or opening beneath the area adjoining the pedicle furrow. This also occurs in the ventral valve of the last-mentioned species (PI. XL VIII, figs. Ic and Id) and in many species of Oholus and its sub- genera and in Lingulella. In other species the area may be thickened so as practically to close up the space between it and the inside of the valve (PI. VII). In Kutorgina (PI. V) the cardinal areas are in a very rudimentarj^ condition, and com- parable with the rudimentary cardinal areas of Micromitra (Pis. II, III, and IV). The general form and structure of Kutorgina, taken in connection with the rudimentary cardinal areas beneath the beaks of the valve, give the areas a significance that those of Micromitra do not possess. It is highly probable that a number of intermediate forms, in which the cardinal areas gradually obtained their more mature character, were developed between the type from which Kutorgina was derived and Nisusia and Billingsella, but nothing is known of such inter- mediate forms in the Lower Cambrian. Schuchertina (PL LI, figs. 6, 6a-m) appears to have been descendant from some atrematous type that may also have been the ancestral stock of Kutorgina and the forms that passed into Nisusia and Billingsella. ScJiucJiertina is a primitive protrematous genus still preserving strong atrematous characters — or vice versa, according to one's point of view. , NEOTREMATA. The cardinal areas of the valves of OholeUa (Pis. LIV and LV) of the Lower Cambrian are essentially the same in appearance as those of Oholus, except that they are not usually so strongly developed. They may also be compared with the cardinal areas of Bicia (PL L), especially the projections on the inner angle adjoining the pedicle furrow. The narrow, thickened cardi- nal margin in the ventral valve of OholeUa does not clearly show from the intei'ior view, although such specimens as that illustrated on Plate LIV, figure 2h, indicate that the area is not so promi- nent as in the ancestral form. This is more clearly shown on Plate LIV, figure 2g. In THE BKACHIOPOD SHELL. 305 Botsfordia cxlata (PL LIX, figs, le, If, and Ik) the cardinal areas are present but subordinate as compared with the areas of Oholella. They are still less in evidence in Botsfordia granulata (PI. LVII, figs. 4g-m) and Botsfordia pulchra (PI. LXII, figs. 5g-j). In Neoholus (PL LXXXI, figs. 2e-h) the reduction of the cardinal areas has progressed until they are no lono-er a marked feature of either valve. In Trematoholus (PL LXXXIII and PL LXXXIV, figs. 5a and 5b) the development of the pedicle tube is much more advanced than in Oholella, but the cardinal areas are here again a prominent feature ; they are less clearly defined in Yorkia (PL LXXXII figs, le-h), in which the pseudodeltidium of the ventral valve is developed (PL LXXXII, figs. Ib-c). In other forms of the Siphonotretidse the cardinal areas as developed in the Obolidse are not seen m the adult stages of growth. It is interesting to note that the vertical tliickened cardinal area is present in the oldest known bracMopod, Trematoholus excelsis (PL LXXXII, fig. 8), wliich occurs stratigrapliically lower dowTi in the Lower Cambrian of North America than any other species of bracliiopod known to me. Linnarssonella, with its low false area and strongly marked interior of its valves has also a well-defined cardinal area in some species (L. modesta, PL LXXVIII, fio-. 8e; L. girtyi, PL LXXIX, figs. 1 1, Im, and Ir), in tliis feature suggestmg that it is more primitive than either Acrotreta or Acrothele. Quebecia is a very ancient form, but so far as known it passed in the adult bej^ond the stage of having a vertical cardinal area. Notliing is known of the interior of Discinolepis of the Middle Cambrian, but in the dorsal valve of Eeyserlingia the tliickened cardinal area is a well-developed feature (PL LXXXI, fig. 4e). Acrotreta occa- sionally shows a vertical cardinal area in the dorsal valve (A. definita, PL LXIV, fig. 2d; A. Tcutorgai, PL LXV, figs. 3h-j ; A. curvata, PL LXVIII, figs. Ik and ll; A. opUrensis, PL LXXIV, fig. If; A. opUrensis descendens, PL LXXVIII, fig. Ic; and A. marjumensis, PL LXXVIII, fig. 2c). Other examples doubtless occur, but it appears that in both Acrotreta and Acrothyra the vertical cardinal areas are absent or so reduced as no longer to be a generic character; the same is to an even greater degree true of Acrothele. Acrothele hellula (PL LVIII, figs. 6c-h) has a defined cardinal area in the dorsal valve and a trace of one on the ventral valve; otherwise, only the false external area back of the jDedicle opening is kno%vn to me among the species of Acrothele, its subgenus Eedlichella, or Schisopholis. Notliing is known of a thickened vertical cardinal area in Orliculoidea or Philhedra. PROTREMATA. Two of the earliest forms of the Protremata (Billingsella (PL LXXXV) and Nisusia (PL O) both have a clearly defined cardinal area on the ventral valve, divided by a delthyrium that is more or less completely covered by a deltidium. These characters appear to be developed in the same manner as in the Inarticulata ; in other words, they are the result of holoperipheral growth and pedicle pressure bulging the mecUan region of the cardinal area. No deltidial plates are kno%vn in the Billingsellidse. So far as known Otusia has an open delthyrium. The cardinal area of Wynnia (PL LXXXIX, fig. 4b) has a large, open delthyrium, with no trace of a deltidium in any of the four specimens from India. The figure shows a bit of shell at the top of the delthyrium, but tliis is not in place. The identification of the subfamily Rafinesquinffi by Eostrophomena is of doubtful value (PI. XCV, figs. 6, 6a-b) and nothing is known of the area of the ventral valve. Eoorthis (PL XCI), Orusia (PI. XCVIII), and FinJcelnburgia (PL XCIII) have an open delthyrium in the ventral valve. The cardinal area of Swantonia (PL CIV, figs. 5 and 6) is unknown. Huenella has a clearly defined area on both valves and an open delthyrium (PL CHI, figs. Ic, 2g, 2i, and 3")- DELTHYRIUM ANB DELTIDIUM. The development of the delthyrium from the simple Rustella stage, where it is scarcely more than a broad opening between the valves, to the definite form in the Iiigher types of the Protremata, where it is either open or more or less closed by a deltidium, has been outlined in 62667°— VOL 51, pt 1—12 20 306 CA^IBRIAN BRACHIOPODA. connection with the notes on the cardinal areas. The evolution iri the Atremata, Neotremata, and Protremata has been in the same direction, rangmg from the open-fissured protegulum stage in pre-Cambrian time to the fully developed, clearly defined, subtriangular, usually convex pseudodelth3Tium and deltidium. In Acrotreta hutorgai the cardinal area and deltid- ium of the dorsal valve are well defined (PL LXV, figs. 3i and 3j). I am inclined to think that the pseudodeltidia of the Atremata and Neotremata, as also the deltidia of the Protre- mata of the Cambrian, are all the result of holoperipheral growth and not of growth from a prodeltidial plate, as interpreted by Beecher [1S92, p. 142]. The deltidia of the Protremata vary in size from the large deltidium of BiUingsella colom- doensis (PI. LXXXV, figs. In and lo) to those iu which the delthyrium is entirely open in the mature stages of the incU^idual. The exact stage at wliich the rudiaientary deltidia resulting from the holoperipheral growth of the shell begin to take on the more definite form shown in Nisusia (PI. C) and BiUingsella (PI. LXXXV) is unknown. From my studies of the Cambrian brachiopods I see notliing that leads me to the belief that in the Protremata the deltidium has a different origin from the pseudodeltidium of the Atremata. Whatever the significance of the prodeltidium or tliird shell plate of the Neotremata may be, it is plain from the many species of Atremata, Neotremata, and Protremata through- out the Cambrian that the pedicle openings tend to develop in two directions; resulting, first, in a more or less large open delthyrium, due in all probability to a tlfick and short peduncle filling up the space, and, second, in a more or less covered delthyrium (the covering being either the phosphatic pseudodeltidium or the calcareous deltidium), the peduncular opening being either between the two valves or reduced to a foramen limited to the ventral valve. LISTRIUM. Hall and Clarke [1892a, p. 153] deemed it important to apply the term listrium to the calcareous deposition or plate closing the progressive track of the pedicle opening or pedicle cleft posterior to the apex of the ventral valve. Tliis feature is known only in Orhiculoidea among Cambrian genera of Bracliiopoda. It has not been observed in the Siphonotretidse. PSEUDOCHILIDIUM. The pseudochilidium is a convex plate closing the primitive aperture in the dorsal valve of Atremata and Protremata. It corresponds to the pseudodeltidium of the ventral valve and is formed about the dorsal side of the pedicle aperture. CARDINAL PROCESS. The cardinal process, hke the crura, was evidently developed in the interval of progression represented between the progenitor of Eutorgina and BiUingsella. The process is unknown in Kutorgina, but is very clearly developed in the Middle Cambrian forms of BiUingsella (PI. LXXXV, figs, lu-y; PI. LXXXVI, figs. 31 and 3n; and PI. LXXXVIII, figs. If and li). I have not observed it in Nisusia or Nisusia {Jamesella) of the Lower and Middle Cambrian. It appears in EoortUs remnicha (PI. XCI, figs. Iq and Ir; PI. XCII, fig. 2b) of the Middle Cam- brian, but I have not seen it distinctly in the Ordovician Protorthis (PL XCIX). The development of the process followed the definite cardinal area and hinge teeth and must at first have been quite rudimentary. Its absence in Nisusia and its presence in BiUings- ella indicate that the latter is a more progressive type in this respect. In the Middle Ordo- vician orthoid Dinorthis subquadrata the cardinal process is striated and fluted so as to give a better holding surface for the attaclunent of the muscles. In the Silurian genera Waldheimia and Oliothyris the entire concave part of the area of the dorsal valve projects as a plate poste- riorly beyond the beak. The cardinal process becomes more speciahzed in its bifurcated condition in the Stropho- menidse and Productidae, etc. (See Hall and Clarke [1892a, p. 168] for further description of this process.) THE BRACHIOPOD SHELL. 307 ARTICULATING PROCESSES. Among the Atremata, Bicia of the Lower Cambrian shows sti'ong projections on the anterior portion of the cardinal area of the ventral valve beside the delthyrium (PI. L, figs, li-k and 2a), but no corresponding sockets or means of articulation in the dorsal valve. It is a matter of interest to note that bosses occur on both valves (PL L, figs. 2, 2a-e) close to the front mar- gin of the cardinal area, which were evidently of service in connection ^vith the mo\'ement of the valves. In DiceUom us the area of the dorsal valve is sometimes grooved in such a manner (PI. LII, fig. li) as to suggest an articulation with a projection on the ventral valve, and the crenulated margin of figure Ij is suggestive of another tendency toward developing articulation of the valves. The actual presence or absence of articulathig processes in Eutorgina cingulata (PI. V) is very difficult to demonstrate by observation, owiug to the character of the matrix in which the specimens occur. That some form of articulating processes is present, however, is indicated b}' the facts (1) that in a relativeh- small collection tliirty of the valves are united, and (2) that in only a few instances is the dorsal valve in any other than the normal position in which it would have been held by teeth in the ventral valve. In only a few of the specimens have the valves slid or turned either wa}', as they usuaUy do in the inarticulates. In the Neotremata, the Lower Cambrian Obolella (PL LV, figs, le-g) has projections suggest- ing an articulating jirocess on either side of the delthvrium. The same is true of Trematobolus (PLs. LXXXIII and LXXXIV). In the Protremata the articulating processes are well developed in BUlingsella (PL LXXXV, figs. In, Iv, and Iw), and, so far as kno^\-n, in Nisusia and the other genera of the order. SPONDYLIUM. I am inchned to agree with Doctor Schuchert that the spondyhum originated as the result of deposition, within the ventral rostral cavity, of testaceous matter about the bases of the adductor, diductor, and pedicle nmscles [Schuchert, 1897, pp. 100-102]. With this conception in mind we may consider that the shghtly demarked rostral muscidar area of Nisusia is one of the earhest known traces of pseudospondyha, and that it is followed by the more decidedly elevated muscidar area or pseudospondyhum of BiUingseUa., which is of the same type as that of Clitamhonites and essentiallj' of the same general type as that of Eoorthis. In Filkelnburgia the pseudospondyhum appears to have been supported at its anterior margin by three septa (PL XCIII, fig. 2), thus forming a link betv/een the pseudospondyhum of BiUingsella and the spon- dj'hum of Syntrophia. In HueneUa (PL CHI, figs. Ih, li, 2 1, and 2m) the spondyhum is free at the sides and -without a supporting septum (as in Syntrophia, PL CII, fig. 6g; PL CIII, figs. 4d and 4e) or septa (as in ClarTcella, PL CIV, figs. 2c and 2d). Protorihis has no well-observed cardinal process in the dorsal valve, although it has gained a true spondyhum in the ventral; and SyntropTiia gains a crurahum in the dorsal valve, both valves of Syntrophia rotundata having either a spondyhum or crurahum supported on a median septum (PL CIII, figs. 4d and 4e). In Clarkella the spondyhum is supported by three or more septa (PL CIV, figs. 2c and 2d). In chronologic order the pseudospondyhum of the ventral valve first appears in the Lower Cambrian BiUingsella highlandensis (PL LXXXVII, fig. 4b) and B. orientalis (PL LXXXVI, fig. 2). It is present in all species of BiUingsella from the jMiddle and Tapper Cambrian, and has the same form in the iliddle Cambrian as in species of Eoorthis of the iliddle and LTpper Cambrian. On this line of descent the pseudospondyhum appears in Orthis (see Hall and Clarke [1892c, pp. 186-194]) of the Ordovician and later faunas, probabty as a reversion from a free spondyhum. On the hne of descent to Protorihis the pseudospondj^hum becomes a free spond3'hum and continues on through Syntrophia and ClarTcella into the Ordovician and Silurian Pentameridse and Chtambonitidte. It is not improbable that all Cambrian and Lower Ordovician Protremata have a pseudo- spondyhum or spondyhum. In the Orthidae a pseudospondyhum is often suggested, but the 308 CAi^IBRIAN BRACIIIOPODA. dental plates do not appear to join to form an attached (pseudo) or free spondylium. The points of attachment of the adductor (central) muscle scars appear to have been directly on the surface of the valve and not on a raised platform or pseudospondylium. At my request, and with all the illustrations of this monograph for study, E. O. Ulrich, who has been studying the Ordovician Protremata, prepared the following notes on the spondylia of the Cambrian and Ordovician Protremata: Spondylium. This structure, if we regard the term spondylium as referring only to the typical free or medially supported umbonal camera or spoon, is of more common occurrence among articulate brachiopods than is usually believed. Hall and Clarke [lS92a, pp. 328-335] discuss the theoretic relations of the spondylium to the deltidium and suggest an expansion of the former term that seems to me to be disproved by the chi'onogenesis of the articulate brachiopods. The typical spondylium is more or less rhomboidal in outline and corresponds to a ventral muscular area which is raised above the floor of the valve and formed by the convergence and union of the dental plates. To the concave surface of this structm-e the ends of the adductor, diductor, and pedicle muscles are attached. The manner in which the spondylium is attached to the bottom of the valve is so variable that the feature does not seem to be of more than generic consequence. It is free in Protorthis and in a related new Ordovician genus; sup- ported by one or three septa in Clitambonites, Pentamerus, Syntrophia (s. s.), Clarkella, etc. ; partly sessile but anteriorly supported by one or three septa in Finkelnburgia; and wholly sessile (resting entirely on the bottom of the vaWe) in Otusia and Onisia, Eoorthis, BillingseUa, Huenella, and certain Clitambonitidie, Syntrophiidse, and Pentameridse. The muscular area of the ventral valve of the Cambrian Orthis-like brachiopods never agrees perfectly with that of any of the described Ordovician Orthid*. In the latter the dental plates of the ventral valve never meet and the area is more or less distinctly bilobed and very rarely elevated, though it may be so depressed in thick shells as to suggest a spondylium. In the Cambrian types in question the muscular area is often elevated, commonly suggests and fre- quently forms a true spondylium, and as a rule is more or less distinctly rhomboidal in outline. These features, together with the arrangement and components of the muscle scars of the dorsal valve, suggest a relationship with the Ordovician ClitambonitidEe rather than with the true Orthidee." Of the true Ordovician orthids, it seems to me that the groups represented by 0. callactis-tricenaria and Dalmanella (especially the D. subxquata section) are the oldest and most persistent. Both of these types often retain umesorbed remnants of the deltidium, and in the development of their dental plates and septa and in the shape and arrangement of their ventral muscular areas they agree with the average Cambrian articulate more closely than do any other Ordo- vician or Silurian orthoids, with the possible exception of Plectorthis. Thus, except in the matter of surface plication, the resemblance between Orthis tricenaria and BillingseUa romingeri (Barrande) is rather striking. But it is to be noted that the muscular area in the ventral valve of 0. tricenana (as in Dalmanella subiequata) is blunt and gently bilobed or obscurely trilobed anteriorly, and not subrhomboidal in outline. Plectorthis ivMtfieldi has longer and broader ventral adductor scars than any other Ordovician or Silurian orthoid known to me, and on this account'its muscular area resembles that of BillingseUa more closely. Plectorthis whitfieldi is, however, of late Ordovician or.-Silm-ian age and lived at a time of very rapid evolution (and possibly reversion) among brachiopods, when other orthoids of the same type {Orthis {BillingseUa) laurentina (Billings) and Orthis fiabelUtes) were reverting to ancestral characters; or it may be that they were immigrants fi'om some other area where the older characters persisted. This difference in shape of the ventral muscular area in the Billingsellidas and Orthid» is due to the fact that in the f-jrmer the median (adductor) scars are always longer and as wide or wider than the lateral (diductor) pair. In the OrthidfB the adductor scars are of the same general shape as the corresponding scars in the Billingsellida;, but are relatively smaller and shorter. They are as long as the diductors in Orthis tricenaria, Plectorthis whitfieldi, and Dal- manella subxquata, and in others [Dinorthis, Rhipidomella, etc.] they are much shorter and more or less completely inclosed anteriorly by the revolutionary tendency of the area of the diductors to expand at the expense of the adductors. A natural division of the orthoids into two families may thus be established: (1) Venti-al muscular area small, obovate or obcordate; adductors reaching front margin of area {Orthis (s. s.), Pkc- torthis, Platystrophia, Hebertella, Orthostrophia, Dalmanella). (2) Ventral muscular area large, bilobed or elliptical; adductors proportionately small and more or less com- pletely inclosed anteriorly by the flabellate diductors [Heterorthis, Plxsiomys? deflecta group, Dinorthis, Bilobites, Rhipidomella, Schizophoria, Orthotichia]. Another well-marked difference between the true Ordovician orthoids and their billingsellid ancestors is in the arrangement of the muscle scars of the dorsal valve. In the Billingsellidae they are somewhat elongate and more or less radially arranged (PI. LXXXVIII, figs. If-k; PI. XCIII, fig. If; and PI. XCIX, fig. 2d) and in the Orthida; [Orthis tricenaria, Plectorthis, Dalmanella, and Orthis tritonia] they are shorter and placed longitudinally. Some of the later orthoid forms in the second group [Bilobites, Rhipidomella, and Schizophoria] are characterized by a radial arrangement of the dorsal muscle scars, but the ventral muscular areas are here highly developed and bear little resemblance to those of the Billingeellidse. " Commenting on this, Dr. Charles Schuchert mote me: " This is a very important point. It has often strucli: me that all the early Cambrian brachiopods have an incipient spondylium, sometimes free, sometimes supported, or sessile. Out of the sessile forms have developed the true orthids." THE BRACHIOPOD SHELL. 309 CRURALIUM. In the dorsal valve an immature cruralium is seen for the first time in Nisusia festinata (PL C, fig. Ig at d, and fig. Ij at cr) wliich is without a cardinal process; this appears to be the ficrst appearance in the Lower Cambrian of a muscle-supporting projection in the dorsal valve of an articulate brachiopod. Li Billingsella a cardinal process is developed (PL LXXXV, figs, lu and Iv) on a low crural thickening. This process is present in Eoorthis and OrtMs and is prominent in DinortMs, Hebertella, and most of the Ortliidge, Strophomenidse, and Pro- ductidsi. A well-developed cruralium in the dorsal valve is first seen in Synfropliia {S. rotundata, PL CHI, fig. 4e) of the Upper Cambrian. It is well developed in Clarkella, Conchidium, and other genera of the Pentameracea. PLATFORM. Hall and Clarke [1892c, p. 46]'' state that — The specialized postniedian testaceous deposit which has been termed the platform by Messrs. Davidson and King occm's among Brachiopoda only in the genera Lakhmina \^Neoholus], Lingulops, Lingulasma, Dinobolus, Trimerella, Monomerella, and Bhinobolus; it constitutes the principal diagnostic character of the family Trimerellidse of those authors, and in so far as any of these genera possesses this featme, so far, at least, it is a trimerellid. In ita chronogenesis it is accompanied by certain peculiar phenomena. According to oiu: present knowledge, its first appear- ance is in the little Lakhmina [=Neoholus\ fi-om the primordial "Obolus beds" in the Salt Range of India; but in American faunas, where the development of the group is best exemplified, it is first met in Dinobolus (in external fea- tiu-es the most oboloid form of the group) ta the later faunas of the Lower Silurian: Black River, Trenton, Galena. Thereupon follow in the still later fauna of the Hudson group the more pronounced linguloid genera, Lingulops and Lingulasma. Not, however, until the introduction of the Niagara or- Wenlock fauna does the entire group, with the exclusion of the inceptive linguloid forms, reach its culmination in specific and individual development. * * * With the disappearance of this fauna the platform-bearing brachiopods virtually became extinct, and we have as yet no trace whatever of the occurrence of this peculiar featm-e at any later date or in any other group of these animals. These authors conclude that it is probable — that the inception of the platform is due to the slight variation indicated in the mode or rate of formation of the muscular fulcra in Lingula, and this may itself have been due in part to a simple increase in the size of the muscular bands. In summing up their conclusions on the source and development of the platform in the trimerellids, the statement is made that "we are confronted with the interesting phenomena of a similar resultant attained along different lines of development." This is "expressed in a diagram in which Obolella and Lingulella are taken as the first stages of two lines of develop- ment. On the line of Oholella come in succession Obolus, ETkania, Dinobolus, and Trimerella. On the line of Lingulella come in succession Lingula, Lingulops, Lingulasma, Trimerella, and, as an oft'shoot from Lingulasma, Monomerella and Rhinobolus. Lalclimina [= Neobolus] is placed in a central line between Obolus and Lingulella [Hall and Clarke, 1892c, p. 52]. For the fuU discussion of the views of Hall and Clarke the student should consult the original work [Hall and Clarke, 1892c, pp. 46-55]. In the course of my studies of the Cambrian brachiopods I came to the conclusion that the platforms so far as developed were the result of shell secretion beneath and about the points of attachment of the muscles, also beneath the visceral cavity. In the dorsal valve of Eus- tella (PL I, fig. le) from the Lower Cambrian, the most primitive type of brachiopod known to me, the central and anterolateral muscle scars are slightly raised above the general level of the interior of the valve ; many natural casts of the interior of the ventral valve fail to show traces of the points of attachment of the muscles. I have assumed that Obolus was divergent from the same stock or radicle as Bustella, and that Lingulella is an early cUvergent from Obolus. (See schematic diagram, p. 317.) None of the Lower Cambrian species of Obolus or Lingulella known to me has any unusual thickening of the valves over the visceral area or about the muscle scars, but in the Middle and Upper Cambrian it is not uncommon to find more or less indication of it. Obolus micJcwitzi (PL X, figs. 1, la-k) of the Middle Cambrian is a striking example, and Obolus apollinis (PL VII) of o Observations on the development and function of the platform in the inarticulate Brachiopoda. 810 . CMIBRIAN BRACHIOPODA. the Upper Cambrian affords fine illustrations of the general thickening of the shell beneath the visceral area in both valves, wliile the points of attachment of the muscles may be depressed (PI. VII, figs. 10 and 17) or elevated (PL VII, figs. 9 and 14). The thickening of the shell is also well shown hj the ventral valves of Obolus (Sclimidtia) (PI. XIV; figs, la, 3a, and 4a) and less well by the dorsal valves (PI. XIV, figs. Ic, 4c, and 4d). Oholus cyane (PI. XXVII, fig. 4b) from the Lower Ordovician has an unusually well-developed thickening beneath the visceral area of the dorsal valve. Many other illustrations might be given from Oholus and its subgenera. In Lingulella and its subgenera there is a strildng development of the primitive or early stages of the platforms, and they are present in many species — L. acutangula (PI. XVII) and L. granvillensis (PL XXII, figs, lb and Id) of the Lower Cambrian and L. duiia (PL XXIV, figs. 4 and 4a) and L. ino (PL XXVI, fig. 4) of the Middle Cambrian. Of Upper Cambrian species only the small L. ferruginea shows a slight tMckening of the valves beneath the visceral area (PL XXIX, figs. Ir and Is). From Lingulella there appears to have been an offshoot in Middle Cambrian time m Oholus (Fordinia) perfedus (PL LXIII, figs. 10, lOa-d) that developed a strong tendency toward the formation of a rudimentary posterior thickening in the interior of the valves. Two species, Obolus (Fordinia) helMus (PL LI, figs. 3, 3a-f) and 0. (F.) gilherti (PL LI, figs. 5, 5a-d) from the Upper Cambrian, also show the same tendency. The rudimentary platform of 0. (Fordinia) ferfectus (PL LXIII, figs. 10a and 10c) is intermediate in development between those of Oholus apollinis (PL VII) and Elkania desiderata (PL LI). The position of the central group of muscle scars, at the anterior sloping ends of elevated ridges, marking the path of advance of the scars with the growth of the shell, is beautifully shown in figure 10a of the ventral valve of 0. (F.) perfedus (PL LXIII). In the dorsal valve of the latter species there is marked thickening of the shell beneath the visceral area, and a marked median septum or ridge just "in front of the cardinal area (PL LXIII, fig. 10c) is very suggestive of a cardinal process. The ventral valve of Elkania desiderata (PL LI, fig. 1) has a strong, solid, rudimentary platform into which the interior cardinal area is blended, and the position of the central group of muscle scars is on the front slope of the platform; in the dorsal valve (PL LI, figs. Ic and Id) a rudi- mentary platform is also clearlj^ indicated. The dorsal valve of Elkama amhigua (PL LI, fig. 2c) may have a fairly strong rudimentary platform or be without it (PL LI, fig. 2b). Elkania ida (PL LI, figs. 4b and 4c) has the rudimentary platform finely developed in both valves. Lingulasrna schucherti [Hall and Clarke,. 1892c, PL II, figs. 17-23] of the Upper Ordo- vician appears to be the best expression of an intermediate form between Oholus (Fordinia) (PL LXIII, figs. 10, lOa-d) and the forms represented by Dinoholus [Hall and Clarke, 1892c, PL IVb] and Trimerella [Hall and Clarke, 1892c, PL IV a] of the Silurian, but it is quite prob- able that Lingulasrna was not in any way intermediate between Fordinia and the trimerellids. It seems to represent a side branch of Lingula. The line of development of the platform to Ordovician and Silurian forms seems to have been from some Oholus-like form, as Fordinia to Neobolus (PL LXXXI, figs. 2e and 2f), and thence to Dinoholus. I thought at one time that Elkania might be a possible ancestral line to the Trimerellidse, but, after carefully considering the position of the rudimentary platforms, I concluded with Schuchert that Elkania was an offshoot from Oholus that did not leave any known descendants. SEPTA. The septum of the dorsal valve of the OboUdse is usually in the form of a narrow ridge, and is not a true septum in the usual sense, which is that a septum is a thin median vertical plate of variable height, terminating freely or supporting a spondylium. Well-developed septa occur in the Syntrophiidse as supports beneatli the spondylia (PL CIII, figs. 3d and 3e; PL CIV, figs. 2c and 2d). DENTAL PLATES. Dental plates first appear,sofar as known, in the Protremata as ooscure processes supporting the teeth of the ventral valve, one on each side of the delthyrium. One of the oldest examples THE BRACHIOPOD SHELL. 311 is that of the Lower Cambrian Nisusia festinata (PI. C, fig. Ij), where the plates form the support of the teeth and also outline a rudimentary spondyUum. Protorthis of the Middle Cambrian has a spondylium on each side of which are the teeth supported at each of the outer angles next to the cardinal area (PI. XCIX, fig. .3b). Dental plates undoubtedly existed in other genera of the Protremata of the Cambrian, but they have not been observed. VASCULAR MARKINGS. The most prominent of the vascular impressions are the pallia! sinuses or main vascular canals. Usually all that is impressed on the inner surface of the valves are the two main tnmks that diverge from near the apex or beak of the valves and skirt the margin of the visceral area. In rare instances the impressions of the secondary branches of the main sinuses are preserved. ATREMATA. None of the shells of the genera of the Paterinidse show more than the bases of the main trunks of the vascular system, but in Oholus and Lingulella and their subgenera there are numer- ous illustrations of the main vascular canals and in a few instances of the secondary canals. Ololus apollinis (PL ^T^I) of the Upper Cambrian has the vascular system' as well developed, judging from the impressions left by it on the interior of the valves, as in the mantle of recent Lingula. In the closely alhed form, Lingulella granvillensis (PI. XXII, figs, lb and Id), from the Lower Cambrian, there is every reason to think that the vascular system has reached its full development. The main vascular trunks, lateral canals, and peripheral canals are all indicated in the ventral valve (PI. XXII, fig. Id). Striking illustrations of the preservation of the mark- ings of the vascular system are shown in many of the illustrations. (See PI. VIII, fig. Id ; PL XII, figs. Ic, le, 9, and 9a; PL XIII, fig. Im; PL XV, fig. 11; PL XVII, figs. Ih and Ij; PL XXXVI, figs. Ic and Id; PL XXXVII, fig. Ic; and PL XXXVIII, figs. 2b and 2d.) In Bicia (PL L), one of the oldest of the Obolidje, the main vascular trunks are very strong, and they are prominent in Dicellomus (PL LII, figs. Id and Ij; PL LIII, figs. Id, 2, and 4a). NEOTREMATA. In the Neotremata, OhoMla, the most primitive form, has the vascular trunks developed (PL LIV, figs. 2g-n) on a scale comparable with those of Oholus, but, as is usually the case among Cambrian bracliiopods, the calcareous shells do not appear to bear the impressions of the secondary canals as well as do the chitinous or phosphatic shells. The main vascular canals of Botsfordia (PL LVII, figs. 4g-m; PL LIX), Linnarssonella (PL LXXIX, figs. Im-p, 2, and 2a), Trematobolus (PL LXXXIII), Yorkia (PL LXXXII, figs. Ih and 2), Schizambon (PL LXXXIV, figs, la, Ic, 2d, 3b, and 3c), and Deariornia (PL LXXXII, figs. 7b and 7c) are all strongly devel- oped. In Acrotliele are found some of the most beautiful examples of the preservation of a highly developed system of vascular canals (PL LVI, figs, la-d, 3b, and 3c; PL LXI, figs. Ic and Id). Acrotreta has relatively large vascular trunks (PL LXIV, figs, li, Ij, and 2c; PL LXV, figs. If, Ig, 3c, and 6; PL LXXIII, figs. 4c and 6), but no traces have been seen of the lateral canals. The main trunks of Acrothyra are also large (PL LXXVI, figs. 4a and 4b). Discinopsis (PL LXXXII, figs. 5a-b) has two narrow, long, main trunks that originate back of the line of the opening of the pedicle tube. PROTREMATA. In Billingsella the great size of the main vascular trunks (Pis. LXXXV-XC) is character- istic of the genus. The manner in which the anterior branches of the main trunlvs pass outward toward the border is finely shown in specimens of B. plicatella (PL LXXXVI, fig. 3i). The dorsal valve of B. exporrecta (PL LXXXVIII, fig. Ik) has two strong apparently main sinuses, on each side; the inner pair, however, may not be casts of the vascular sinuses, but may indicate grooves made by the path of advance of the attachments of the posterior adductor muscles. The vascular system of Nisusia (PL C) and its subgenus Jamesella (PL CI), Protorthis (PL XCIX), and usually of Eoorthis, has left no traces of its presence on the shell. On some 312 CMIBKIAN BKACHIOPODA. examples of Firikelnhurgia (PI. XCIII, figs. Id, If, 2, and 2b) there are indications of large main trunks, and in Orusia (PI. XCVIII, figs, le and Ip) narrow trunks are seen. Only one among many hundreds of specimens of Eoorthis (PI. XC'I, fig. 3b) shows traces of the main trunks. Among the Syntrophiidse, HueneUa ahnormis (PI. CIII, figs. 2b and 2h) shows that the main trunks were of large size. I have not seen any interiors of the shells of the Strophomenidse from the Cambrian sj^stem. TMs brief review proves that the simple primitive type of the circulatory system, as developed in the main vascular canals, their laterals, and the peripheral canals of the mantle, was fully developed in Lower Cambrian time, and that this type persisted throughout Cambrian time. The modified form of the canal system of the Craniidse has not been observed, nor has the complex canal system of the Ordovician and later orthoids [Hall and Clarke, 1892c, Pis. Va, Vc, VI, and VIA]. MUSCLE SCARS. It is only within a few years that material has been available from Cambrian rocks that could furnish data for a description of the muscle scars and by them an outline of the muscular system of the Cambrian brachiopods. ATREMATA. In theAtremata this has been most thoroughly worked out for Oiolus byMickwitz (1896), and an outline may be found in this monograph under the description of the genus Oholus. The terminology used in this monograph is mentioned on page 292. In the most primitive form of brachiopod known to me, Rustella edsoni, the muscle scars of the dorsal valve, so far as known, indicate that the system of scars was essentially the same as in Oiolus. In the dorsal valve the central scars (PI. I, fig. le) are preserved; also the anterior portion of the outhne of the parietal band, which indicates the position of the anterolateral scars. Although we have a number of good natural casts of the interior of the ventral valve, no traces of vascular marldngs or muscle scars have been observed. So far as known none of the many hundreds of specimens of various species of Micromitra have preserved any definite outlines of the muscle scars, and the same is true of Mickwitzia and Helmersenia. Oiolus and Lingulella and their subgenera all have the same general grouping of the muscle scars as described under Oiolus. For Oiolus these are well shown in 0. apollinis (PL VII) ; ioT Lingulella by L. acutangula (PI. XVII) ; for the subgenus Westonia by Oiolus (Westonia) escasoni (PL XLIX, figs, la, laa, Ic, and Id). The same general arrangement of the muscle scars, so far as known, is found inBicia (PL L), Elkania (PL LI), and Oiolus {Fordinia) (PL LXIII,figs. 10a and 10c). In Z^iceZZomws the central and the outside and middle lateral scars are located in front of the visceral area, as in Oiolus, but the anterolateral and transmedian scars are combined in one large cardinal scar (PL LIU, fig- Ic at cl), as in Acrotreta (PL LXIV, figs. 2c and 2d) ; in the dorsal valve the central and anterolateral scars are as in Oiolus, while the transmedian, outside laterals, and middle laterals appear to be grouped in one large cardinal scar (PL LIU, fig. li at cl). The combining of the muscle scars of the posterolateral region of the valves in one large scar in this genus of the Atremata foreshadows the typical large cardinal scar so characteristic of the Neotremata. NEOTREMATA. In Oiolella (Pis. LIV and LV) the arrangement of the muscle scars, so far as known, is that of Oiolus, but with a tendency on the part of the posterolateral scars to close in toward each other; this tendency is carried into effect in Botsjordia (PL LIX, figs. Ik and In; PL LVII, fig. 4k; and PL LXII, figs. 5g and 5i). In the dorsal valve of Botsfordia pulcTira (PL LXII, fig. 5h) the transmedian and middle lateral scars appear to be distmct, but in figure 5i and in • all ventral valves, figures 5g and 5j , a single large scar appears to be present. In Linnarssonella, which I have placed as the descendant from the Acrotreta stock (schematic diagram, p. 317), the posterolateral scars are all grouped in both valves in a large cardinal muscle scar (PL LXXIX, figs. Ik-p). The muscle scars of the central portion of the valves remain essentially as in Oiolus. THE BKACHIOPOD SHELL. 313 The system of muscle scars in Trematoholus (PI. LXXXIII) is, so far as knowii, that of Oholus, with a modification probably of the position of the scars of the pedicle muscles; of the latter, unfortunatelj^, nothing is Ivnown. Dearbornia (PI. LXXXII, figs. 7b and 7c) has the same arrangement of the muscle scars as Trematoholus, but of the muscle scars of the other genera descendant from the Trematoholus stock we know very little. The interiors of Svphonotreta (PL LXXXI, figs. 6c, 6d, and 6e) indicate an arrangement somewhat hke that of Trematoholus. Yorkia, Orhiculoidea as loaown in the Cambrian, and Philhedra show nothing of the muscle scars. ScJiizamhon (PL LXXXIV) appears to be related in its muscle scars to Trematoholus. The muscle scars of Acrothele, Acrotreta, and Acrotliyra agree in having the posterolateral scars united on each side in one large cardinal scar situated in the posterolateral region of the valves. The central and anterolateral scars of the dorsal valve are variously situated (PL LVIII, figs. 5f and 5h, and PL LX, fig. 1 1) in the central portion of the mterior of the valve, but not more so than in the dorsal valve of Oholus. In the ventral valve the outside and mid- dle laterals and the central scars are more or less contracted, and drawn back toward the small visceral area about the pedicle opening; the individual scars have not been seen except in one specimen of Acrotreta argenta (PL LXVII, fig. 5b). In this species the visceral area is unusually large and the positions of the outside lateral and central scars is shown ; the anterolaterals are not delinfited. Another species of Acrotreta, A. opliirensis (PL LXXIV, fig. le), has an unu- sually large visceral area, but, although the area of the muscle scars is defined, the individual scars can not be seen. No reference has been made to the umbonal muscle scars, as thej^ are so rarely preserved. They are well developed and shown in Oholus and Lingulella, and it is highly probable if not certain that some form of umbonal muscle existed in all of the inarticu- late brachiojDods. PKOTKEMATA. The muscles of the Protremata are limited to three sets: diductors, to open the valves; adductors (centrals), to close the valves; and the pedicle muscles. In KutorginO; the atrematous progenitor type of the Protremata, the anterior and poste- rior adductors (equal to the anterolateral and central scars, respectively) are known in the dorsal valve (PL V, fig. Ih), but nothing is Icnown of the pomt of attachment of the diductor muscles in the dorsal valve or of any muscles in the ventral valve. The muscle scars are preserved in Billingsella in the ventral valve witliin the area of the iDseudospondylium. The diductors probably occupied the outer divisions of the tripartite pseudospondylium and the adductors the central section. This is well shoAvn in many specimens (PL LXXXV, figs. Im and Ip; PL LXXXVI, figs. 3g, 3i, 3j, 3k, 3m, and 4b; PL LXXXVII, figs. 5b, 5c, and 7; and PL XC, figs. 2g, 2h, and 2i). The diductors appear to have followed closely in the line of the scars of the main vascular sinvises if the tripartite pseudodeltidium is considered to have been whollj^ taken up by the points of attachment of the muscles. In the dorsal valve the adductor scars are often prominent (PL LXXXVIII, figs. Ig, Ih, Ij, and Ik), also the cardinal process to which the diductor muscles were attached. The interiors of the ventral valves have not thus far shown muscle scars. The muscle scars of the ventral valve of Nisusia and its subgenus Jamesella, and those of Finlcelnhurgia, Orusia, and Protortliis, were probably gathered on a pseudospondylium or, when the latter is not defined, on the bottom of the valve beneath the umbo, as in Eoorthis. Tn an obscure specimen of the dorsal valve of Portortliis quacoensis (PL XCIX, fig. 2d) the pos- terior adductor scars appear to be preserved. In the dorsal valve of Finkelnhurgia the adductors are finel}^ shown (PL XCIII,fig. If), also a rounded, posterior central depression in which the diductors may have been attached. Among the Cambrian Syntrophiidee muscle scars have been discovered in Huenella ainor- mis of the Upper Cambrian. In the ventral valve (PL CHI, fig. 2b) the adductor and diductor scars are preserved on the spond3dium, and dorsal valves (PL CIII, figs. 2f, 2i, and 2j) show the adductors in fine preservation, also the crurahum to which the diductor muscles were attached. The muscle scars of this species are of unusual interest, as the ventral valve has a spondylium to which the pedicle, the large diductor, and the smaller scars of the adductor muscles were attached. 314 CAMBEIAN BRACHIOPODA. PEDICLE TUBE AND APERTURE. ATBEMATA. Wlien the pedicle rests in furrows on the areas of the valves, as in Oiolus (Pis. VII and XIV), it pertains to both valves, but with the deposition of a narrow band of shell about it on the ventral valve it strictly pertains to this valve alone, altliough it may still I'est against the area of the dorsal valve before passing through the semitube of the ventral valve. The transition froni the deep but open pedicle furrow of the ventral valve of Oholus to the inclosed sheath or tube of OholeUa is found in Dicellomus politus. In this species there has been a deposit of shelly matter that rises up from the sides of the jjedicle furrow on the ventral valve and arches slightly inward, almost forming a tube in places; M'hat remains of this semitube is shown bj' figures 16A and 16B. NEOTREMATA. The earliest and simplest stage of development of the pedicle tube when it completely surrounded the pedicle is found in Obolella of the Lower Cambrian (Pis. LIV and LV). In this genus the deep pedicle furrow of the ventral valve of Dicellomus has been covered over just at the apex of the cardinal area so as to form a simple ring or tube about the pedicle. In the next stage, as shown by Botsfordia (Pis. LVII and LIX), the pedicle has advanced its opening to the front side of the apex and the tube between it and the furrow in the area is a little stronger and a trifle larger. In Linnarssonella (Pis. LXXVIII and LXXIX) the opening of the pedicle tube is close to the posterior margin and the Obolella-like struc- ture in both valves is very striking. This is best seen by comparing the casts of the interior of the ventral valves of Linnarssonella (PI. LXXIX, figs. 3c-g) with those of OholeUa atlantica (PI. LV, figs. If-h). In both species the cast of the pedicle tube is in the same position in relation to other parts, and the external opening of the pedicle tube is at the apex above a low false cardinal area. The depressed forms of Acrothele, with the apex near the posterior margin, appear to have been descendant from the Obolella stock but to have reached a stage of development more advanced than any known form of the Cambrian genus Obolella. Acrothele bellula (PI. LVIII, figs. 5, 5a-h) of the Mddle Cambrian appears to be one of the oldest forms and to have retained in its ventral valve characteristics of its oboleUoid ancestors. In the ventral valve the pedicle tube penetrates the thickened apex of the shell and there is considerable space between the pedicle aperture and the posterior margin ; the tube and aperture are essentially the same in all the species of Acrothele, difl'ering only in details due to a rather narrow range of position and the varying thickness of the shell. The genus Schizopholis (PI. LXXXI, figs. 1, la-c) has a more nearly vertical posterior slope and distinctly marked false area, in this respect resembhng the large group of species referred to Acrotreta. The pedicle tube and aperture of the latter are of the same type as in Acrothele, difl'ering only in form and position witlun a narrow range. Acrothyra also shows little variations. Biscinolepis (PI. LXXXI, figs. 3 and 3a) has the pedicle operung more advanced and appears to be a form intermediate between Acrothele and Acrotreta. Figure 16. — BlcellomusiiolUusiXl^]!). A, Interior of ventral valve (fsp, pseudospondylium or pedicle plate; i, transraedian scars; j, anterolateral scars; v, visceral cavity; vs, main vascular sinuses) . B, Posterior portion of the interior of a ventral valve, showing a strongly developed area (fsp, pseudospondyliiun or pedicle plate; a, inside section of area; f, flexure line; a', outside section of area). The specimens represented by figures 16A and 16B are from Locality 79s, Upper Cambrian "St. Croix sandstone" at Hudson, Wisconsin (U. S.Nat. Mus. Cat. Nos. 51917aand 51917b, respec- tively). The same figures are reproduced on page 570. DISTRIBUTIOX. 315 The pedicle tube of Keyserlingia (PI. LXXXI, fig. 4c) apparently opens into an elongated depression in the shell back of the apex of the ventral valve ; the tube is a passage through a thickened mass of shell which is deposited about the pedicle and wliich is especially well developed in old sheUs (PI. LXXXI, 'figs. 4a and 4d). PROTREMATA. A pedicle tube or opening is found in the genus BillingseUa of the Lower Cambrian, the characteristic opening being at the apex of the delthyriuni (fig. 65, p. 750). It has not been observed in Nisusia (PL C) nor in the subgenus JameseUa (PI. CI), nor in &iyj other genus or subgenus of the Protremata of the Cambrian fauna. Tliis may be owing to the absence of a deltidium in the adult stages of the shell found, to its being covered by the incurved beak, to the difficult}' of worldng out or uncovering the deltidium so that it can be seen, or in all proba- bihty to the permineraHzation of the shell and the generally coarse nature of the sediments deposited \x\ih the shells. It may be that the opening was closed naturally in the adult stages as in some of the Ordo^ncian Clitamhonites. Even in BillingseUa, where the material is abundant and Avell preserved, it is only rarely that an entire deltidium is obtained and very rarely that the minute pedicle opening can be seen at its apex. OLB-AGE CHARACTERS. I have not given special attention to old-age characters during the progress of the study of the Cambrian brachiopods. The variations due to old age during the gerontic period appear in the unusual thickening of the shell of Oholus apoUinis (PL "VII), but old age is not indicated on the exterior of the shell (PL XIV, figs. 6 and 6a). The areas of attachment of the muscles in Obolus mickwitzi (PL X) suggest old age, and the strong concentric ridges at the front of the valves is another phase of old-age conditions. Oholus (Lingvloholus) (PL XVI), in its tliick shell, large deep muscle scars, and convex valves indicates an old-age form derived from Obolus. In Keyserlingia huchi (PL LXXXI, figs. 4a-e) the interior shell growth associates the species with old-age forms. There is abundant material for study of many of the species described in tliis volume that may, when carefully worked up and studied, give some interesting resxilts in relation to changes in the shell during the mature (neologic) and old-age (geratologic) periods of growth. DISTRIBUTION^IN CAIMBRIAN STRATA. We do not kno\v of any brachiopods in strata older than that containing the Mesonacidas or Lower Cambrian fauna. That such existed in pre-Cambrian time seems almost certain when the advanced stage of development of some of the ea^hest-lvno^^'n forms is considered. In the foUoATOig diagram the Icnown occurrence of the famihes of brachiopods in strata of Cambrian age is graphically sho^vn. The diagram is based on the data contamed in the table (p. 112) giving a summary by families. The Obolida?, M-ith 6 genera, 9 subgenera, 186 species, and 14 varieties, has the greatest development, and tliis family continues into the base of the Ordo- vician mth 4 genera, 3 subgenera, 41 species, and 1 variety. The Acrotretidte has 6- genera, 1 subgenus, 100 species, and 20 varieties, -with the greatest development m the Middle Cambrian and with a smaher representation in the Lower Ordovician. The Billmgsellidse, with 9 genera, 2 subgenera, 91 species, and 12 varieties, has a strong line of development from the upper iiiddle Cambrian and passes into the Ordo\'ician, where it disajjpears. The three families mentioned include about 48 per cent of the genera, 80 per cent of the subgenera, SO per cent of the species, and 79 per cent of the varieties included in the Cambrian Brachiopoda. The development of genera of the remaining families containing 3 genera or more is as follows: Paterinidse, 3; OboleUid^, 4; Siphonotretidse, 6; Syntrophiidge, 3; or 16 genera of the 23 outside 316 CA^iIBRIAX BRACHIOPODA. of the Obolidse, Acrotretidse, and BiUingsellidfP, which contain 21 genera. The remaining 7 famihes inckide 7 genera. Of the 44 genera from the Cambrian, 19 occur in the Lower Cambrian, 31 in the Middle Cambrian, and 20 in the Upper Cambrian. < _J O \- < E o SUPERFAMILIES LOWER CAMBRIAN MIDDLE CAMBRIAN UPPER CAMBRIAN si -'cc o FAMILIES Pentameracea SyntfOphiidae ^^' Strophomenacea --' Strophomenidae -'' / Orthacea j-'' 1^' . Billingsellidae ■^■^■^^un 1^ — Kutorginacea 1 ^-^ ..'' .-- Schuchertinidae ^^--^ Kutorginidae < -I 3" O H -c 2 £ o o Craniacea i Craniidae / Discinacea i / Discinidae A * X 1 '-' — Acrotretidae IV^I mil Siphonotretidae Siphonotretacea i i i ^^^ Obolellidae ^^ ^' 5 1 o < 1 1 >'' Obolacea 1 X ,,-— ^ ^^^^^^^^^ H^H ■ Obolidae ' Curticiidae ^"" ^^^ 1 Rustellacea -"'ll- -""^' "* _ Paterinidae Rustellldae Figure 17. — Diagram illustrating known distribution of families in Cnmbrian strata. EVOLUTION OF THE CAMBRIAN BRACHIOPODA. SCHEMATIC DIAGRAM. In order to formulate, so far as possible, in a graphic manner my conception of the evolution and lines of descent of the Cambrian Brachiopoda, gained bj' the investigations described in this monograph, a schematic diagram (fig. 18) has b§en prepared. This diagram is necessarily tentative and incomplete, but it will serve to point out my present conceptions of the lines of evolution of the various genera, and it shon^s clearly the very rapid development of the primitive atrematous genera in early Cambrian time. The genera identified from each of the thi-ee divisions of the Cambrian may be ascertained by glancing at the colunms headed Lower, iliddle, and Upper Cambrian for the generic and subgeneric names included in each column. The most primitive but not the oldest species known to me from the Cambrian formations is Rustella. edsoni (PI. I, figs. 1, la-e). This is found in association ^^'ith Olenellus thompsoni in Vermont, where it occurs at nearly the summit of the Lower Cambrian, and not low down toward the base of the Cambrian system. Probabty the oldest-loao^va brachiopod, or the species lowest in the stratigrapliic series, is Trematoholus excelsis (PI. LXXXII, figs. 8, 8a-d). This is far advanced in development and must have had a long line of descent from the protegulum. stage. Another very ancient type is Micromitra. A species %vith ornamented surface (31. {Iphidella) louise) occurs 2,850 feet down in the Lower Cambrian of the Canadian Rockies and Micromitra (Iphidella) pannula (PI. I"\') is abundant in the upper portion of the Lower Cambrian. Micromitra (Paterlna) labradonca (PI. II) is found deep in the Lower Cambrian of New Brunswick EVOLUTION. 317 LOWER CAMBRIAN MIDDLE CAMBRIAN UPPER CAMBRIAN ORDOVICIAN WimanellaO- Wiinanella Q Eoorthis -o Eostrophomena Eoorthii '-0 Orthii -d Finkeln- Billingse K>^ OmsiaO- ,.-'0'tusiaO Billings'ella _,'"" burgia — o "O Eoorthis Finkeln-p, burgia Billingsella o ' Jamesella o- / NisusiajO" X "-^ tonia Wynnia~0 Jamesella -D O Nisusi; -o — o Protorthis p-Syntrophia OLoperia -OJamesella Protorthis o Syntrophia Huenella o -QSyntrophi; O Clarkella O Kutorgina -Q Schuchertina 'D- Iphidella Iphidella p. MickwitziaO ^Micjomitra Micromitra HeliTiersenia Q Micrornitra ,' OVolborthia /,--^'^ Paterina Paterina Paterina -o 3 1 ' 3 \ \ Q. _Rustella 'O ,--0 Dicellomus o '- Obolu Elkania __._..— o ,0 Neobolus OFordinia -ODicellomus Elkania Obolus .-''' -O ^C-O Broggeria SchmldtiaO Curticia^O/'' /,' Obolus -''' / /' O Westonia Westonia O Acritis O Obolus Mickwitzeira-6'Dh'"2"" ^ lobolus \ DelgadellaQ X Linguiella y' ^O Palseobolus Linguiella -^ Lingulepis Linguiella ^"-^^ t?^*?!!]^^'?"./ V~ Lingula Lingulepis O Westonia ■Q Linguiella {3 Lingulepis '"OQ'^^becia Botsfordia ^ 0 ',Q y Obolella ■o O Acrothele ,0 Schizopholi -OBotsfordia Q Discinolepis ORedlichella ,''' Acrothele Acrothele AcrotretaQ; Linnarssonella -O DiscinopsisQ Acrotreta Linnarssonella o Acrotreta 5 Trematobolus ''^p^ Acrothyra ^ Orbicuioidea ^ .Q^ Trenna-^ APhilhe- Orbicuioidea YorkiaO tobolus ro (y dra Schizambon DearborniaO -Q- O Acrothele Acrotreta o Orbicuioidea Philhedra Schizambon Siphonotre_t_a_ Figure 18.— Schematic diagram of evolution of Cambrian Brachiopoda. 318 CA^IBRIAN BRACHIOPODA. and is the oldest brachiopod kno\\aa from the Atlantic Province. Bicia (PI. L), OholeUa (Pis. LIV and LV), Quebecia (PI. CIV), Botsfordia cselata (PI. LIX), Acrothele I ella punctata (PI. LVII, figs. 3, 3a-b), A. decipiens (PI. LYIII, figs. 3, 3a-d), A. woodwortM (PI. LX, fig. 6), Acrotreta emmonsi (PI. LXV, fig. 6), A. primseva (PI. LXIX, figs. 1, la-f), and Yorhia (PI. LXXXII) occur with other forms in the upper portion of the Lower Cambrian fauna. All of these examples of inarticulates indicate that the brachiopod fauna had advanced far in its evolution in Lower Cambrian time. Among the progenitors of the Protremata, Kutorgina (PI. V) occurs in the ^lesonacidje fauna, and Schuchertina (PI. LI) of the Mddle Cambrian probably springs from the Kutorgina stock in Lower Cambrian time. Among the articulates we find, of the order Protremata in the Lower Cambrian, several species of Billing sella (Pis. LXXXVI-LXXXIX), Nisusia (Pis. C and CI), and Swantonia (PI. CIV), all from the upper zone of the Mesonacidsa fauna. (See fists of genera and species, pp. 98-109.) ATREMATA. The most primitive form of the Atremata kno-\\'n to me is BusteUa edsoni (PI. I, figs. 1, la-e) of the upper portion of the Lower Cambrian tei'rane. It is without a false cardinal area, and there is only a sKght indication of a pedicle furrow; some of the less well-preserved shells suggest the protegiilum stage of the Brachiopoda. Mickwitzia (PI. VI, figs. 1" and 3), Helmersenia (PL LXIII, figs. 7b and 7d), and Yolborthia (PI. I, figs. 6 and 6e) have an obscurely defined false cardinal area on the ventral valve. In Helmersenia the pedicle opening is produced by the gaping of the valves; in Volhortnia (fig. 33, p. 366) it is produced by the bulging of the cardinal margins. In Micromitra (Pis. II, III, and IV) the posterior margins of the valves may be nearly closed as in M. pealei (PL III, figs. 3b and 3e'), or have a more or less open delthyrium as in M. (Iphidella) pannula (PL IV, figs. Id, If, 2a", 2b', 4a', and 4d'). In Curticia (PL I, figs. 2', 2b, 2a", and 2d) the open delthyrium is more developed than in Micromitra, although the cardinal area is not outlined. Curticia appears to be a form intermediate in character between Micromitra of the Paterinidfe and Obelus of the Obofidse. It shows no trace of a pseu- dodeltidium or any closing of the delthyrium by an extension of the area across it. In the graphic systematic scheme (p. 317) it is placed as a family descendant from Obolus. In the diagram on page 317 the lines of descent of the various genera are graphically out- lined, but our information is often so fragmentaiy that the scheme is necessarily imperfect. In this the Eustella type of the upper Lower Cambrian is assumed as the loiown form that most nearly approaches the protegulum stage or the first stage in which it would be possible to have a brachiopod preserved as a fossil. From the jpre-Bustella radicle Micromitra developed in early Cambrian time and continued nearly to the close of the Upper Cambrian, giving rise in the Lower Cambrian to Michwitzia and in the Upper Cambrian to Helmersenia and VoTborihia. Obolus, branching from the BusteUa protegulum radicle, is first known in the Lower Cam- brian a little later than Micromitra. It persisted on into the Ordovician, giving rise in early Middle Cambrian time to its subgenera Palxobolus and ^Yestonia, in late Mddle Cambrian time to Fordinia and to 0. (Acritis?) rugatus. Other subgenera, Schmidtia, Broggeria, and Mickwitzella, appeared in late Upper Cambrian or early Ordovician time. Bicia is taken from the -pre-Obolus- radicle. Dicellomus appears in central iliddle Cambrian strata and continues into the ITpper Cambrian. It probably originated in the Bicia phj^llum in Lower Cambrian time. Elkania begins in central IMiddle Cambrian strata and continues well into the Upper Cambrian. It appears to have been an ofi'shoot from Obolus \ntliout known direct descendants. Neobolus, with its pecuhar platforms pointing to the future Trimerelhdse, is probably a descendant from some Lower Cambrian form that branched off from Obolus. The descendants of Neobolus, if such existed, are imknown in the late IMiddle and LTpper Cambrian. Curticia is given as an offshoot from Obolus in L'pper Cambrian time and Lingulobolus in the Lower Ordovician. Fordinia appears to have been an offshoot from Obolus in Middle Cambrian time and to have disappeared without descendants. EVOLUTION. 319 It is assumed that Lingulell(i-]ike forms developed from primitive Oiolus in early Cambrian time, -since the genus is first known from the lower portion of the Lower Cambrian and is known to occur throughout the Cambrian and into the Ordovician. The subgenus Lingulepis appears in iliddle Cambrian time and continues on into the Lower Ordovician. Little is known of Delgadella of the Lower Cambrian, but from its form it is referred to the Lingulella phyUum. Lingula is probably descendant from Lingulella in late Cambrian time. Lingulella davisi (PL XXXI, figs. 6e, 6f) is quite similar to Lingula, as are Lingulella lens, L. concinna (PI. XXXIII), and other Upper Cambrian species. The subgenus Leptembolon branches off from Lingulella in late Upper Cambrian time. Matthew [1902b, p. 9S] has given a diagram showing "Conjectural Lines of Descent of the Canadian Oboli with Reference to the Oldest Known Atremata." This diagram and the discussion following it are based upon Matthew's observations in the Cambrian section of New Brunswick and Nova Scotia and liis interpretation of the genera and species. The greater opportunity offered by larger coUections from a much wider field has so changed the data upon which his conclusions were based that I shall not enter into a discussion of them. Kutorgina (PL V) is assumed to have branched off from the Micromitra radicle in pre- Cambrian time, and from its fine of descent or radicle Schuchertina (PL LI, figs. 6, 6a-m) is taken off. Both of these genera are placed on the border fine between the Atremata and Protremata. NEOTREMATA. The progressive increase in the differences in form and the relations of the two valves in the genera of the Neotremata is best seen by a glance at the diagram on page 317. In tliis an 06oZeZZa-Kke type is descendant fi-om a simple form like the Eustelta radicle and from this radicle the Acrotretidae diverges. Acroihele, with its great vertical range from the Lower Cambrian to the Ordovician and its wde geograpliic distribution, is the oldest and simplest form; Acrotreta is derived from Acrothele, and is first kiiown toward the close of the Lower Cambrian and continues through to the Ordovician; from the Acrotreta branch Acrothyra and Discinopsis diverged in Middle Cambrian time. Linnarssonella is assumed to have branched off from the Acrotreta radicle, and it is knowm to have continued from the central Middle Cambrian to later Upper Cambrian time. Another branch from Acrotreta leads to Orhiculoidea in the central Middle Cambrian, wliich continues on into the Ordovician. A shell doubtfuUj'- identified as PhiThedra occurs in the Mddle Cambrian. If correctlj^ identified it represents the Cramidse in the Cambrian fauna. Botsfordia is an offshoot from Oholella in the central Lower Cambrian, and I have assumed it to be the progemtor of ScMzopholis of the Middle Cambrian. Quehecia of the middle Lower Cambrian is tentativelj^ sho-wTi to be derived from the Oholella radicle. Another branch is Trematoholus, which is assumed to be the direct progenitor of the Siphon- otretidse as an offshoot of the Oholella primary stock. Yorlcia is the first knowTi branch from Trematoholus in Lower Cambrian time. Deariornia, as knowTi, is limited to the upper portion of the Middle Cambrian. PROTREMATA. The ancestral types of the true Protremata are, so far as at present kno^vn, Nisusia and Billingsella. These appear to have come from the radicle leading from Micromitra to Kutorgina of the Lower Cambrian. Kutorgina is placed on the border line between the Atremata and Protremata without direct descendants. ScliucTiertina (PL LI, figs. 6, 6a-m) has a calcareous shell, smooth outer surface, poorly defined cardinal areas, open delthyrium, and large muscle areas on the ventral valve. It sug- gests one of the transition forms between Kutorgina and Nisusia, but as its stratigraphic posi- tion is in the central iliddle Cambrian, far above and much later in time than the early forms of the fines of descent of the Protremata, it is placed on the border line without descendants. 320 CAJNIBRIAN BRACHIOPODA. The earliest representatives of the Nisusiinse are Nisusia and its subgenus JameseUa; both occur in the upper portion of the Lower Cambrian. Nisusia is unknown later than the upper portion of the iliddle Cambrian, and JameseUa is unkno^vn above the base of the Upper Cambrian. ProtortMs, along with its subgenus Loperia, is first known in the central portion of the Middle Cambrian; it disappears toward the close of the Upper Cambrian. Billingsella is known from the central Lower Cambrian and on to nearl}^ the close of the Upper Cambrian. Of the genera of the Billingsellidse other than Billhigsella, Wynnia occurs in the ]\Iiddle Cambrian. Orusia appears in the upper portion of the Middle Cambrian and continues well up into the LTpper Cambrian, and Otusia is found in the upper part of the Middle Cambrian. None of these genera appear to have had descendants in Ordovician time. Wimanella, although a more primitive form than Billingsella, is not known to occur as low down in the Lower Cambrian, and its upper range is only to the upper portion of the Middle Cambrian. It is derived fi'om the Billingsella radicle. Eoorthis is first known from the lower portion of the Middle Cambrian and continues through the Upper Cambrian into the Ordovician. Its line of evolution through Billingsella appears to have been from the same radicle as Nisusia, which occurs in the upper portion of the Lower Cambrian. The genus Finkelnburgia is derived from Eoorthis in the lower portion of the Upper Cambrian. The Ordovician genus Orihis is assumed to have developed from Eoorthis in late Cambrian time, and Eostrophomena in the early Upper Cambrian. Syntrophia, beginning in the lower Middle Cambrian, continues into the Ordovician, and appears to have descendants in ClarJcella and in Huenella. Swantonia suggests the 'Rhynchonellidse in form, but it has a spondylium and it ma}^ have been the progenitor of both Syntrophia and Protorthis. It is represented in the diagram as an offshoot from the radicle of Nisusia, without descendants. A review of the characters of the various subgenera of Orthis from the Ordovician strata leads us to expect to find repre- sentatives of Dinorthis in the Cambrian. According to Hall and Clarke [1892a, p. 195] this form is characterized bj^ having the ventral valve depressed so that it is flat or concave over the palhal region, in this respect resembling Hebertella [Hall and Clarke, 1892a, p. 198]. Among Cambrian forms Protorthis (Loperia) dugaldensis (PI. XCIX, figs. 5, 5a-h) of the Middle Cambrian has the depressed ventral valve, but otherwise it differs from Dinorthis in having a spondylium in the ventral valve and in the absence of a cardinal process in the dorsal valve. Thus far there appear to be no representatives of Orthis, Plectorthis, Orthostrophia, Platijstrophia, Heterorthis, Bilohites, Dalmanella, or other Ordovician or Silurian orthoids among the Cambrian species. In endeavoring to trace a genetic connection between the Cambrian Billingsellidse and the Orthidas of the Ordovician we are met at once with the great hiatus caused by lack of material for study and comparison from the formations between the Upper Cambrian and the Middle Ordovician. The Orthidas of the Middle Ordovician include a large group of brachiopods, differing radically from the BillingsellidiB in shell structure, whose ancestral line in the Lower Ordovician and Upper Cambrian is imknown. That this break will be filled is highly probable, but meantime the more or less conjectural lines of descent of various authors must be carefully reviewed in each case in connection with all the stratigraphic and paleontologic evidence afforded by all kno-wai Lower Ordovician formations, especially in the American and European areas. Systematic studies now in progress by members of the United States Geological Survey may afford much valuable information that will be of service in this connection. CAMBRIAN BRACHIOPODA. 321 CLASSIFICATION. That we may have a graphic illustration to aid in description, the following table and scheme are inserted. The ordinal classification of Beecher [1891], with emendations, is taken as the basis for the orders, while the arrangement of superfamilies is practically that of Schuchert [1897], with such emendations and additions as greater information has rendered necessary. Table of classification of Brachiopoda. Eh icia. ■ \Dicellomus. . Kutorgina. .Schuchertina. Obolellidse. Siphonotretidae . AcrothelinsB. Obolella. (Glyptias). Botsfordia. Schizopholis. ,(?)Quebecia. Yorkia. Dearbornia. Trematobolus. Schizambon. Siphonotreta. .Keyserlingia. fAcrothele. (Redlichella). Discinolepis. ILinnarssonella. Acrotreta. Acrothyra. Discinopsis. Discinidse Orbiculoidea. Craniidae Philhedra. ci 9, a ty . a' D < < L I Acrotretinse . rt ^ ^ ^ hr G o ^ « Nisusiinte. Billingsellinae. o =5 ii !^k [^■^ P c o a 43 (U INisusia. (Jamesella). Protorthis. (Loperia.) Wimanella. Billingsella. Orusia. Otusia. Wynnia. fEoorthis. "IFinkelnburgia. Rafinesquinae Eostrophomena. Eoorthinse. PmJ Syntrophiidae I(?)Swantoma. Syntrophia. Huenella. ClarkeUa. 62667°— VOL 51, pt 1—12- -21 322 CMIBRIAN BRACHIOPODA. Order ATREMATA Beecher [1891, p. 354]. (Emended Schuchert [1897, p. 119] and Walcott [1908e, p. 142].) Primitive inarticulate corneous or calcareophosphatic Brachiopoda with the pedicle emerging more or less freely between the two valves. Growth takes place in general around the anterior and lateral margins. Specialized forms show tendency to develop rudimentary articulation. Delthyrium originally unmodified, in later genera modified by pseudodeltidia and pseudochUidia, or by thickened, striated, and more or less furrowed or even cleft vertical cardinal margins, the ventral cleft in most specialized forms tending to inclose the pedicle and finally restrict it to the ventral valve; when completely so the genera are referred to the order Neotremata. Superfamily HUSTELLACEA Walcott [1908e, p. 143]. Primitive, thick-shelled, corneous or calcareophosphatic Atremata developing more or less of pseudodeltidia and pseudochilidia. FamUy RUSTELLID^ Walcott [1908e, p. 143]. Primitive Rustellacea with the delthyrium small, open, and not much modified by pseudo- deltidia or pseudochilidia. Muscle scars and vascular sinuses not well defined in the shell. Bustella Walcott [1905a, p. 311]. FamUy PATERINID.ffi; Schnchert [1893, p. 151]. I (Emended Schuchert [1897, p. 119] and Walcott [1908e, p. 143].) Progressive Rustellacea with the delthyrium more or less closed by pseudodeltidia or pseudochilidia. MicJcwitzia Schmidt [1888, p. 24]. Micromitra Meek [1873, p. 479]. (Paterina) Beecher [1891, p. 345]. (Iphidella) Walcott [1905a, p. 305]. Volborthia Kutorga [1848, p. 277]. Ci.) HelmerseniaT andev [1861, p. 48]. Superfamily OB GLACE A Schuchert [1896, p. 305]. (Emended Schuchert [1897, p. 119] and Walcott [1908e, p. 143].) Derived (in Rustellacea), progressive, thick-sheUed, calcareophosphatic or corneous Atre- mata without pseudodeltidia and pseudochilidia. Rounded or linguloid in outline, more or less lens-shaped, and fixed by a short pedicle throughout life to extraneous objects. Family CUETICIID.ff; Walcott and Schuoliert [Walcott, 1908e, p. 143]. Primitive Obolacea with a high well-defined delthjrrium. Interior characters much as in Obolidse. Curtida Walcott [1905a, p. 319]. FamUy OBOLID^ Eingr [1846]. (Emended Schuchert [1897, p. 119] and Walcott [1908e, p. 143].) Derived, progressive Obolacea with thickened, striated, vertical cardinal areas traversed by pedicle grooves. Muscles and vascular trunks strongly impressed in the valves. Subfamily OBOLIN'.a: Dall [1870, pp. 164 and 161]. (Emended Walcott [1908e, p. 143].) Primitive Obolidae with the pedicle grooves more or less shallow or deeply rounded, but never tending to form a sheath or to completely restrict the pedicle opening to the ventral valve. The radicle of the Trimerellidse, by way of the Neobolinse, appears to be in this sub- family in the thick-shelled Middle Cambrian forms of Oholus (s. s.). CLASSIFICATION. 323 Ololus Eichwald [1829, p. 274]. (Broggeria) Walcott [1902, p. 605]. {Palseobolus) Matthew [1895b, p. 201]. (Fordinia) Walcott [1908d, p. 64]. (LinguIoMus) Matthew [1895b, p. 260]. (Miclcwitzella) Walcott [1908d, p. 70]. (Acritis) Volborth [1869, p. 212]. {Sclimidtia) Volbortli [1869, p. 208]. {Westonia) Walcott [1901, p. 683]. LinguleUa Salter [1866b, p. 333]. (Leptembolon) Mickwdtz [1896, p. 199]. {Linpulepis) Hall [1863, p. 129]. Delgadella Walcott [1908e, pp. 142 and 144]. SubfamUy ELKANIIlSiiE Walcott and Schuchert [Walcott, 1908e, p. 144). Divergent Obolidse with posterior or marginal (not central) platforms, to which are attached the central and outside and middle lateral muscles. Elkania Ford [1886b, p. 325]. Subfamily NEOBOLINJE Walcott and Schuchert [Walcott 1908e, p. 144]. Progressive Obolidse with posterior platforms, to which were probably attached the central and outside and middle lateral muscles. Subfamily apparently progressive from the Oboluise to the Trimerellidse, though the platform is posterior and not subcentral as in the trimerelloids. Neoholus Waagen [1885, p. 756]. Subfamily BICIIN'^ Walcott and Schuchert [Walcott, 1908e, p. 144]. Progressive Obolidse with the pedicle restricted to the ventral valve and more or less inclosed by a pedicle tube, and with rudimentary articulation. The transgressing stock from the Atremata to the Neotremata (Obolellidffi) . Bida Walcott [1901, p. 676]. Dicellomus Hall [1873, p. 246]. Superfamily KUTORGINACEA Walcott and Schuchert [Walcott, 1908e, p. 144]. Progressive, thick-shelled, almost calcareous atrematous-like shells, tending to be trans- verse and developing rudimentary articulation, more or less rudimentary cardinal areas, pseu- dodeltidia, and muscle scars prophetic of the Protremata. Derived out of Rustellacea. Family KUTORGINID.ffi Schuchert [1893, p. 151]. (Emended Schuchert [1897, p. 131] and Walcott [1908e, p. 145].) Progressive transverse Kutorginacea with rudimentary cardinal areas, great delthyrial opening, rudimentary articulation, and immature pseudodeltidia. Muscle scars prophetic of the Strophomenacea . Kutorgina Billings [1861b, p. 9]. Family SCHUCHERTINID^ Walcott [1908e, p. 146]. Primitive round Kutorginacea with small cardinal areas. Externally like Oholus, with an open subtriangular delthyrium which apparently is without a pseudodeltidium. Muscle scars and vascular markings prophetic, through the Billingselhdse, of the Strophomenacea. Schuchertina Walcott [1905a, p. 323]. Order NEOTREMATA Beecher [1891, p. 354]. (Emended Schuchert [1897, p. 129] and Walcott [1908e, p. 145].) Derived and specialized inarticulate Brachiopoda (through the Obolidse of the Atremata), as a rule more phosphatic than calcareous, more or less cone-shaped, with the pedicle emerging during life through a perforation or sheath in the ventral valve, or a triangular more or less 324 CAMBEIAN BRACHIOPODA. open cleft, or onl^y so in the youngest-shelled stage, after which the ventral valve becomes attached by a pedicle to foreign objects. Pedicle cleft in derived forms modified by a listrium. Pseudodeltidia and pseiidochilidia as a rule not well developed. Superiamily SIPHONOTRETACEA Walcott and Sclmchert [Walcott, 1908e, p. 145]. Primitive, thick-shelled, calcareous or corneous, oboloid Neotremata, with the pedicle passing through a ventral sheath, the aperture of which may remain apical and circular in outline, or it may become elongate through resorption by passing anteriorly through the pro- tegulum and umbo of the shell. A listrium is not developed. Dorsal protegulum marginal. FamUy OBOLELLID^ Walcott and Schuohert [Walcott, 1908e, p. 14S]. Primitive Siphonotretacea with the pedicle emerging through a small circular perforation in the apex of the ventral valve, posterior to the protegulum. Derived out of the Obolidae. Oholella Billings [1861b, p. 7]. (Glyptias) Walcott [1901, p. 675]. Botsfordia Matthew [1891, p. 148]. Schizopholis Waagen [1885, p. 752]. (?) Quehecia Walcott [1905a, p. 320]. FamUy SrPHONOTEETID.a; Kutorga 11848, p. 2531. Small Acrotretidse with more or less liigh ventral valves. Linnarssonella Walcott [1902, p. 601]. Acrotreta Kutorga [1848, p. 275]. Acrothyra Matthew [1901b, p. 303]. Discinopsis (Matthew MS.) Hall and Clarke [1892c, p. 105]. 1 Described as Siphonotretseae. ^ Wrongly credited to Walcott and Schuchert [Walcott, 1908e, p. 146]. CLASSIFICATION. 325 Superiamily DISCINACEA Waagen [1885]. (Emended Schuchert [1897, p. 130] and Walcott [1908e, p. 146].) Derived Neotremata with phospliatic shells, a listrium modifying the pedicle slit, and without pseudodeltidia and false cardinal areas. Dorsal protegulum usually subcentral. Family DISCINID.ffi Gray [1840). (Emended Schuchert [1897, p. 130] and Walcott [1908e, p. 146].) Discinacea with an open pedicle notch in early life in the posterior margin of the ventral valve, which is closed posteriorly during neanic growth, leaving a more or less long, narrow slit partly closed by the listrium. Orhiculoidea d'Orbigny [1847]. Superfamily CRANIACEA Waagen [1885]. Cemented calcareous specialized Neotremata without pedicle or anal openings at maturity. Family CEANIID.ff; King [1846]. Craniacea with the pedicle functional probably only during nepionic growth. Philhedra Koken [1889, pp. 465, 467]. Order PROTBEMATA Beecher [1891, p. 355]. (Emended Schuchert [1897, p. 131] and Walcott [1908e, p. 147].) Progressive (though atrematous Kutorginacea), articulate calcareous Bracluopoda with well-developed cardinal areas. The pedicle opening is restricted to the ventral valve tlu'ough- out life or during early growth, and is often modified and more or less closed by a deltidium. Often there is a cliilidium. Brachia unsupported by a calcareous skeleton other than crura. Superfamily ORTHACEA Walcott and Schuchert [Walcott, 1908e, p. 147]. Derived, progressive Protremata. Cruralia and rudimentary spondylia (pseudospon- dylia) free or cemented (through sessility) directly to the valves. Sometimes without deltidia and chilidia. Cardinal process more or less well developed except in the most primitive genera. FamUy BILLINGSEI,LID.ffi: Scliucliert [1893, p. 152]. (Emended Schuchert [1897, p. 132] and Walcott [1908e, p. 147].) Primitive Orthacea with an open or more or less closed delthyrium. Cardinal process well developed, rudimentary, or absent. Usually with a clearly defined pseudospondylium, to wliich the muscles of the ventral valve were attached. Shell structure dense, granular, lamellar, nonfibrous. Subfamily NISUSIIN.a; Walcott and Scliuchert [Walcott, 1908e, p. 147 Primitive Orthacea with more or less well-developed deltidia and with or without rudi- mentary chilidia. Spondylia and cruralia rudimentary or small and not supported by septa. Cardinal process rudimentary or absent. Nisusia Walcott [1905a, p. 247]. (Jamesella) Walcott [1905a, p. 252]. Protorthis Hall and Clarke [1892c, p. 273]. {Loperia) Walcott [1905a, p. 287]. Subfamily BILLINGSELLIN.ffi: Walcott [1908e, p. 148].a Primitive Orthacea very much like Nisusiinse, but without true spondylia and cruralia. There is a more or less well-developed cardinal process except in Lower Cambrian forms. Wimanella Walcott [1908d, p. 98]. Billingsella Hall and Clarke [1892b, p. 230]. Orusia Walcott [1905a, p. 273]. Otiisia Walcott [1905a, p. 246]. Wynnia Walcott [1908e, pp. 142 and 148]. a This subfamily is wrongly referred to Schuchert, 1893, by Walcott [1908e, p. 148). 326 CAMBRIAN BRAOIIIOPODA. SubfamUy EOORTHINiE Walcott H908e, p. 148], Derived Orthacea nearly always with large open delthyria; deltidia and chilidia occasion- ally retained tliroughoiit life, but more often only in the younger-growth stages. Cardinal process well developed. Shell structure dense, granular, and with punctate lamellae. Eoorihis Walcott [1908d, p. 102]. Finkelnburgia Walcott [1905a, p. 277]. Superfamily STKOPHOMENACEA Schuchert [1896, p. 312]. (Emended Schuchert [1897, p. 131] and Walcott [1908e, p. 148].) Derived, progressive, terminal Protremata, out of Ortliacea (Billingsellidse). Deltidia and clailidia nearly always well developed. Cardinal process always well developed. Family STROPHOMEinD.ffi King [1846]. Subfamily EAFlNESQiriN.aE Schuchert [1893, p. 153). ■ (Emended Schuchert [1897, p. 132] and Walcott [1908e, p. 148].) Strophomenoids having generally a convex ventral and a concave or nearly flat dorsal valve. Eostrophomena Walcott [1905a, p. 256]. Superfamily PENTAMERACEA Schuchert [1896, p. 320]. (Emended Schuchert [1897, p. 134] and Walcott [1908e, p. 148].) Specialized Protremata with well-developed free or supported spondylia and cruralia. Deltidia and cliilidia usually absent. Family SYNTROPHIIDiE Schuchert [1896, p. 320). (Emended Schuchert [1897, p. 135] and Walcott [1908e, p. 148].) Primitive Pentameracea with long, straight cardinal areas. (?) Swantonia Walcott [1905a, p. 296]. SyntropUa Hall and Clarke [1892c, p. 270]. Huenella Walcott [1908d, p. 109]. Olarkella Walcott [1908d, p. 110]. DESCRIPTION OF GENERA AND SPECIES. Order ATEEMATA Beecher. [a, without; and tp^/w, perforation.] Superfamily RUSTELLACEA Walcott. Family RUSTELLIB^ Walcott. aenus BtrSTELLA Walcott.o Rustella Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 311. (Mentioned as a new genus, the type species being described.) RusUlla Walcott, 1908, Smithsonian Misc. CoU., vol. 53, No. 4, PL XI, and pp. 142 and 143. (Classification of genus.) This genus is founded on RusteUa edsoni Walcott. It appears to be the most primitive form of brachiopod known. The single specimen of Rustella ? major (IMatthew) does not add to our knowledge of this genus, and it may belong to some other genus. The generic name is given in memory of William P. Rust, of Trenton Falls, Oneida County, New York, whose collections from the Lower Cambrian strata of Georgia, Franklin County, Vermont, were the most extensive and the material the finest obtained there, so far as known to me. Rustella edsoni Walcott. Plate 1, figures 1, la-e. Oholella (Kutorgina) dngulata Bullngs (in part), 1861, Geol. Survey Canada, Paleozoic Fossils, vol. 1, p. 8, fig. 9 (not figs. 8 and 10, which represent specimens of the true Kutorgina dngulata). (Described and discussed as a new species.) Oholella {Kutorgina) dngulata Billings (in part), 1861, Report on the Geology of Vermont, vol. 2, p. 948, fig. 348 (not figs. 347 and 349). (Copy of preceding reference.) Oholella {Kutorgina) dngulata Billings (in part), 1862, Report on the Economic Geology of Vermont, by Hager, p. 220, fig. 348 (not figs. 347 and 349). (Copy of preceding reference.) Oholella dngulata Billings, 1863, Geol. Survey Canada, Fifteenth Rept. Progress, p. 284, fig. 287c (not figs. 287a and 287b, which represent specimens of the true Kutorgina dngulata and are copied from Billings, 1861b, p. 8, figs. 8 and 10, respectively). (No text reference. Fig. 287c is copied from Billings, 1861b, p. 8, fig. 9.) Kutorgina dngulata Waicott (in part) [not (Billings)], 1886, Bull. U. S. Geol. Survey No. 30, p. 103, PI. IX, figs. Ig and Ih (not figs. 1, la-f, which represent specimens of the true Kutorgina dngulata). (Specimens now referred to Rustella edsoni are here mentioned in the discussion of Kutorgina dngulata as representing a possible distinct species. The specimens represented by figs. Ig and Ih are redrawn in this monograph, PI. I, figs, la and 1, respectively.) Kutorgina dngulata Walcott (in part) [not (Billings)], 1891, Tenth Ann. Rept. U. S. Geol. Survey, p. 609, PI. LXIX, figs. Ig and Ih (not figs. 1, la-f, which represent specimens of the true Kutorgina dngulata). (No text reference. F^s. Ig and Ih are copied from figs. Ig and Ih of the preceding reference.) Rustella edsoni Walcott, 1905, Proc. II. S. Nat. Mus., vol. 28, pp. 311-312. (Described and discussed as below as a new species.) General form subcircular, biconvex. Ventral valve moderately convex, with the apex at the margin immediately above a low arch in the posterior margin. Surface smooth except for concentric growth lines and low ridges that in some shells are quite prominent. A shallow, broad, rudimentary pedicle groove occurs beneath the apex and on a slightly flattened space adjoining the posterior margin. Dorsal valve about as convex as the ventral and with the apex marginal. The interior of the valve shows two rounded depressions beneath the umbo with a slight, narrow groove between them; a httle in advance the outlines of the central muscle scars occur; rather strong but faintly indicated radiating lines occur toward the front. o Before Rustella was proposed by Walcott [1905a, p. 311] the species now included under the genus were placed in the following genera: Oioldla (Kutorgina) Billings [1861b, p. 8; 1861c, p. 948; 1862e, p. 220]. Obolella Billings [1863, p. 284]. Kutorgina Walcott [1886b, p. 103]. Obolus Matthew [1890, p. 155]. Kutorgina Walcott [1891a, p. 609]. Mickwitzii Mickwitz [1896, p. 23]. 327 328 CAMBRIAN BRACIilOPODA. Ohservations. — This shell was identified as the dorsal valve of Kutorgina cingulata by Bill- ings [lS61b, p. 8, fig. 9] and as the ventral valve of the same species by myself [1886b, p. 102, PI. IX, figs. Ig and Ih, and 1891a, p. 609, PI. LXIX, figs. Ig and Ih]. They were considered as distorted, flattened shells. Better material shows them to represent one of the simplest forms of brachiopod known; with the exception of the rudimentary pedicle furrow and area there is nothing more than the gaping valve, much hke Charles E. Beecher's ideal "Paterina" [1891, p. 345]. The specific name is given in recognition of the excellent work of Mr. George Edson, of St. Albans, Vermont, in collecting the Lower Paleozoic fossils of that region. Formation and locality. — Lower Cambrian: (25)" Sandstone just above Parker's quarry, near Georgia; and (319r) on the Bullard farm about 2 miles (3.2 km.) east of Swanton; both in Franklin County, Vermont. (392o) Arenaceous limestone collected somewhere in Vermont (exact location unknown). (49) Sandstone on Codorus Creek, 0.125 mile (0.2 km.) below Meyer's mill, near Emigsville; and (49a) sand- stone on the Liverpool road, south of the schoolhouse, 3 miles (4.8 km.) northwest of York; both in York County, Pennsylvania. RusTBLLA? MAJOR (Matthew). Text figure 19. Oholus f major Matthew, 1890, Trans. Roy. Soc. Canada for 1889, 1st ser., vol. 7, sec. 4, No. 12, p. 155, PL VIII, fig. 3. (Described and discussed as a new species; see below for copy of description. The specimen represented by fig. 3 is redrawn below, fig. 19.) Mickwitzia ? major (Matthew), Mickwitz, 1896, M6m. Acad. imp. sci. St.-P6tersbourg, 8th ser., vol. 4, No. 2, p. 23. (Discussed in German.) The original description by Matthew follows: Only the dorsal valve known. This is transversely oval, flattened near the umbo, and deep \vithin the edges toward the back of the shell. The interior markings seem those of an Oholus. The median line is strongly marked just within the umbo, and at the middle of the shell, in front of which it appears to fork. The scars of the posterior laterals only are distinct. The example known shows the interior of the shell and a little of the external surface. FiGUEE 19.—Eustella? major The shell was thin, and is changed to iron oxide. The outer surface near the edge of the (Matthew). A, A', Cast from a ghell was covered by fine radiating lines or ridges, natural mold in sandstone; side outline restored. From Observations. — The type and only specimen of this form is preserved Locality 301v, Lower Cam- ■'.^ ■' ^ , ■ • i i n i i i brian shales on Hanford as a natural mold m an impure sandstone; the ongmal shell had been Brook, New Brunswick, removed, and the resulting mold is very similar to those of Rustella collections of the University edsofii (PI. I, figs. 1 and la) from a fine-grained sandstone; in the case of Toronto. The cast from ^^ ^^^ latter species Only a film remains to indicate the~original shell, while in the collections of the u. s. in the calcarcous nodules embedded in the sandstone the shell is shown National Musemn, Cat. No. ^ ^ f considerable thickncss. 5U62. This specimen was -n -n ■ i ^ i • -i -x • figured by Matthew [1S90, PI. The reference to the genus KusteLLa is based on the sinularity in VIII, fig. 3]. g-^g ^j^^ form between this species and Rustella edsoni and the fact that Rustella? major occurs at about the same stratigraphic horizon in the Lower Cambrian as R. edsoni and below the recognized Middle Cambrian fauna. At the same locahty and at about the same horizon I found several Lower Cambrian fossils: Micromitra (Paterina) labradorica, Eyolithes cf. communis, Goleoloides cf. typicalis [Walcott, 1900, p. 322]. Formation and locality. — Lower Cambrian: (301v [Matthew, 1890, p. 155]) Sandy shales of Division 2b of the "Basal series" of Matthew, on Hanford Brook, St. John County, New Brunswick, Canada. a The type locality is in italics; where there is but one locality, however, this will not be italicized. When a locality is not represented in the collections of the United States National Museum, the authority for its citation is given immediately after the locality number, or at the end of the paragraph, if several can be grouped under the one reference. CAMBRIAN BRACHIOPODA. 329 Family PATERINID^ Scliucliert. Genus MICKWITZIA Schmidt." Mickwitzia Schmidt, 1888, Mto. Acad. imp. sci. St.-Petersbourg, 7th ser., vol. 36, No. 2, p. 24. (Described in German as a new genus.) Mickwitzia Schmidt, Hall and Clarke, 1892, Eleventh Ann. Rept. State Geologist New York for 1891, p. 246. (De- scribed.) Mickwitzia Schmidt, Hall and Clarke, 1892, Forty-fifth Ann. Rept. New York State Museum for 1891, p. 562. (Copy of preceding reference.) Mickwitzia Schmidt, Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, pp. 86-87. (Described and discussed.) Causea Wiman, 1902, Bull. Geol. Inst. Univ. Upsala, vol. 6, pt. 1, No. 11, pp. 53-54. (Described and discussed in German as a new genus, the description being incorporated with that of the type species, Causea formosa.) Mickwitzia Schmidt, Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 4, PI. XI, and pp. 142 and 143. (Classifica- tion of genus.) Shell large, unequivalTe. Ovate or subcircular, with apex of valves within the margin and erect, or curved over the margin. A false cardinal area may or may not be obscurely defined ; valves not articulated. Shell substance mostly calcium phosphate and arranged in three prin- cipal layers. The outer layer is papillose, with fine and large punctse; middle layer marked by numerous radiating and concentric, more or less elevated lines and small punctse that become very numerous toward the front margins of the shell; inner layer marked by large punctse or vertical canals and often a thickening of shell substance that takes the form of irregular ser- pentine ridges penetrated by vertical canals. TyiJe. — Lingula ? monilifera Linnarsson. Ohservations.— Both Schmidt [1888, p. 24] and Hall and Clarke [1892c, pp. 86-87] define and discuss this genus, but with the new material I have for study, a new diagnosis has been prepared. The genus appears to fall withm the order Atremata Beecher [1891, p. 354] and the family Paterinida3 Schuchert [1897, p. 119]. The latter family has heretofore included only the genus Micromitra. The species of Mickwitzia include cMtinous or phosphatic shells with elevated ventral valve, having an apex elevated within the margm {Mickvntzia formosa (Wiman)), or arcliing over the margin {llickwitzia monilifera (Linnarsson)). Micromitra has a clearly marked area and pseudodeltidium, in this respect being further advanced in evolution than Mickwitzia. A series of sheUs of Mickwitzia might show a more strongly marked false area in the young shell than in the adult forms. The generic name was given in honor of Dr. A. Mickwitz. Mickwitzia Formosa (Wiman). Plate VI, figures 3, 3a-c. Causea formosa Wiman, 1902, Bull. Geol. Inst. Univ. Upsala, vol. 6, pt. 1, No. 11, pp. 53-54, PI. II, figs. 1-5. (De- scribed and discussed in German as a new species. The specimen represented by figs. 1-5 is redrawn in this monograph, PL VI, figs, 3, 3a-c.) Outhne of ventral valve circular; apex a little in front of the posterior margin, strongly elevated, and rising verticaUy above a broad, obscurely defined false area. The area is defined by a rounded angle where the transverse, shghtly convex posterior surface below the apex unites with the lateral slopes from the apex. The posterior margin is shghtly arched, so as to form an opening between it and the dorsal valve. Only the inner layers of the shell are preserved on the type specimen, the outer epidermal layer having been exfoUated. On the posterior portion of the shell the second or middle layer has the radiatmg and concentric lines typical of Mickwitzia monilifera (Linnarsson). Toward the front the layer of shell is marked by faint racUating lines and many fuie punctse, exactly as in specimens of M. monilifera, where the outer layer is exfohated. This type of surface is a Prior tD the definition of Mickwitzia by Schmidt [1888, p. 24], the species now referred to this genus were placed under the following genera: Lingula Linnarsson [1869a, p. 344; 1869b, p. 398]. Obolus Linnarsson [1S71, pp. 9-10]. 330 CAMBRIAN BRACIIIOPODA. shown by Plate VI, figure Ik, except that the punctiB are very few on the center of the shell, which is the part enlarged by the figure. The inner layer of shell of M.formosa has numerous large punctae that penetrate it, and also the irregular serpentine ridged shell deposits charac- teristic of this species and of many adult shells of M. monilifera. Ohservations. — Wiman [1902, p. 53] created the genus Oausea to receive this species. He very kuadly sent me the type material for study, and with it a fine collection of M. monilifera (Linnarsson) . I am iinable to determine generic distinctions between the two species. The shell substance and structure are the same, so far as material exists for comparison. Mickwitzia formosa has a more elevated apex and is a much larger shell, but these are specific rather than generic distinctions. Formation and locality.— Middle? Cambrian: (3111 [Wiman, 1902, p. 57]) Drift bowlder of bluish calcareous sandstone, No. 31, on Biludden, about 20 miles {32.2 km.) east ofGefle, Province ofGefleborg, Sweden. (311s [Wiman, 1902, p. 57]) Drift bowlder of gray quartzitic sandstone, at Skarpnito, Aland Island, Finland, Russia. Mickwitzia monilifera (Linnarsson). Plate VI, figures 1, la-p; Plate LIX, figure 2. Lingula? monilifera Linnarsson, 1869, Ofversigt af K. svensk. Vet.-Akad. Forhandl. for 1869, Bd. 26, No. 3, p. 344, PI. VII, figs. 1 and 2. (Described and discussed in Swedish as a new species.) Lingula monilifera Linnarsson, 1869, Geol. Mag., vol. 6, p. 398, PI. XI, figs. 1 and 2. (Text translated into English from Ijinnarsson, 1869a, p. 344. Figs. 1 and 2 are copied from Linnarsson, 1869a, PL VII, figs. 1 and 2.) Obolus? monilifer Linnarsson, 1871, Bihang till K. svensk. Vet.-Akad. Hand!., Bd. 9, No. 7, pp. 9-10, PI. I, figs. 2 and 3. (Described and discussed in Swedish.) Mickwitzia monilifera (Linnarsson), Schmidt, 1888, Mem. Acad. imp. sci. St.-P6tersbourg, 7th ser., vol. 36, No. 2, pp. 21-23 and 24-25, PI. II, figs. 6-26. (Described and discussed in German. Figs. 12c and 12d are copied in this monograph, PI. VI, figs. Ip and lo, respectively.) Mickwitzia monilifera (Linnarsson), Walcott, 1891, Tenth Ann. Kept. U. S. Geol. Survey, PI. LXX, figs. 2, 2a-h. (No text reference. Figs. 2, 2a-f are copied from Schmidt, 1888, PL II, figs. 16a, 16c, 16b, 12b, 12c, 12d, and 12a, respectively. Fig. 2h is copied from Linnarsson, 1871, PI. I, fig. 2.) Mickwitzia. monilifera (Linnarsson), Hall and Clarke, 1892, Eleventh Ann. Rept. State Geologist New York for 1891, figs. 253-255, p. 246. (No text references. Figs. 253-255 are copied from Schmidt, 1888, PI. II, figs. 14a, 8b, and 16b, respectively.) Mickwitzia monilifera (Linnarsson), Hall and Clarke, 1892, Forty-fifth Ann. Rept. New York State Museum for 1891, figs. 253-255, p. 562. (Copy of preceding reference.) Mickwitzia monilifera (Linnarsson), Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, p. 86, figs. 42-44. (No text reference. Figs. 42-44 are copied from Schmidt, 1888, PI. II, figs. 14a, 8b, and 16b, respectively.) Mickwitzia monilifera (Linnarsson), Wiman, 1902, Bull. Geol. Inst. Univ. Upsala, vol. 6, pt. 1, No. 11, p. 53, PL II, figs. 12-14, PL IV, figs. 2 and 3. (Characterized and discussed in German.) General form ovate to subcircular; biconvex or subplanoconvex. Surface of exterior of the shell papillose; each papilla is about as high as the width of its base, and the apex is perforated by a minute tube. There appears to be no systematic arrangement of the papillse ; they are thickly set over the entire surface of a dorsal valve 20 mm. in diameter; on some parts of the shell the papillse are closely arranged in undulating, irregular ridges ; these, when worn by attrition, have the appearance shown by Plate VI, figure Im. This outer surface is rarely preserved, as it usually adheres to the matrix, leaving the second layer exposed to view. The layer of shell immediately beneath the outer shell is marked by concentric, elevated, minutely undulating, raised, closely set lines that are crossed by fine, radiating, closely set raised lines (PI. VI, figs. Ik and 1 1) ; this is the surface illustrated by Linnarsson [1869b, PI. XI, fig. 2] and Schmidt [1888, PI. II, fig. 21]; it is seen on most specimens preserving the shell. The distance from the apex, condition of preservation, etc., cause great variation in the appearance of the inner layer. Scattered punctae penetrate the inner layer, and often the depressions between the concentric and radiating raised lines give the surface a finely and regularly pitted or punctate appearance. On some shells the punctse are numerous and regu- larly arranged toward the front of the shell. The inner surface of the inner layer of the shell is marked by strong punctse in adult shells. Frequently a shell deposit is found over the inner PATERINID^. 331 surface wliich is punctate and curiously ridged, very much like the outer surface in partly worn shells. (See PL VI, fig. Im, of the outer surface.) Substance of shell mostly calcium phosphate [Schmidt, 1888, p. 2.3]. The shell is thick in small shells, but does not increase proportionately in thickness with age. The largest shell in the collection before me has a length of 32 mm., exclusive of extension of apex over area; width 30 mm. Ventral valve convex, ^^■ith apex projecting a little over the posterior margin. A false area is more or less definitely outlined ; in some specimens it is quite clear and in others very indefi- nite ; it is much like some of the less clearly defined false areas of species of Micromitra. When well defined the posterior margin of the valve arches slightly, as in Plate VI, figure le. Dorsal valve shghtly convex, with a very low submarginal apex. The interior of the valve is usually without traces of muscular or vascular markings. In one worn shell a median sinus occurs, and what appears to be the path of advance of the anterolateral muscle scars (PL VI, fig. If) ; another unworn sheU shows a trace of radiating lines near the median line; and a third has two plainly marked muscle scars a little in advance of the apex and some distance from the median line ; these occupy the position of the posterior muscle scars as they occur in the dorsal valve of Schizocrania. Observations. — The preceding description is based on specimens in the collection of the United States National Museum. Mr. Schmalensee, a collector in the Geological Survey of Sweden, at my request collected a number of fine specimens for the United States National Museum. The museum has also received a number of casts from other sources. Schmidt [1888, p. 22] describes a hooked process as occurring in a cast of a dorsal valve. After noting his expression of doubt as to whether the process belonged to the shell, and also after a study of the interiors of finely preserved dorsal valves, I can not retain the view that such a process exists in the dorsal valve of this species. We may attribute the apparent occur- rence of it in the cast studied by Schmidt to the accidental attachment of some foreign body, or it may be that the cast belongs to some other genus and species. There is no other species of the genus that is closely related to Mickwitzia monilifera; M. formosa has the same general character of shell, but its ventral valve is more erect, much larger, and it differs a Httle in the details of the surfaces of the interior layers of the shell. Formation and locality.— Middle? Cambrian: (3111 [W'iman, 1902, p. 57]) Drift bowlder of bluish calcareous sandstone, No. 31, on Biludden, about 20 miles (32.2 km.) east of Gefle, Province of Gefleborg; and (311u [Wiman, 1902, p. 57]) drift bowlder of blue calcareous sandstone, Soderarm lighthouse, near Norrtelje, Province of Stockholm; both in Sweden. (3He) Drift bowlder of rusty sandstone, south of Lumparn, parish of Jomala; (311f) drift bowlder of gray quartz- itic sandstone, at Slemmem, Mariehamn; (311q) drift bowlder of gray quartzitic sandstone, at Ytternasetj^ Mariehamn; and (311r) drift bowlder of gray quartzitic sandstone, at Granboda, Lemland; all [Wiman, 1902, p. 57] on Aland Island, Finland, Russia. Lower Cambrian: (390]) Eophyton sandstone at Lugnas, 8 miles (12 km.) south-southwest of Mariestad, Province ofSharaborg; and (390k) Eophyton sandstone at Prestorp, north of the hill of Billingen, Province of Skaraborg; both in Sweden. (3964) Upper boundary of the blue clay with the Fucoid sandstone, the "Mickwitzia conglomerate" at Reval; (396r) in the "upper strata" at Streitberg, near Reval; (396s) in loose blocks on Kosch Brook near Likkat, near Reval; (396t) at the sandstone capes of Ziegelskoppel, Kakkomaggi (also Rocca al Mare), near Reval; (396u) in loose blocks on the lower course of Jaggowal Brook, about 20 miles (32.2 km.) east-southeast of Reval; (396v) at the upper boundary of a dolomitic sandstone with which the Olenellus stratum begins, below the cement factory on Kunda Brook; a and (396w) in the glauconitic sands above the main mass of the clay, below the cement factory on Kunda Brook; all [Schmidt, 1888, p. 24] in the Government of Esthonia, Russia. Mickwitzia occidens Walcott. Plate VI, figure 4. Mickwitzia occidens Walcott, 1908, Smithsonian Misc. Coll., vol. 8, No. 3, p. 54, PI. VII, fig. 1. (Described as below as a new species. Fig. 1 is copied in this monograph, PL VI, fig. 4.) Only crushed and broken specimens of this shell are available. One of these shows that the apex of the ventral valve was a little above the posterior margin of the shell, very much as a Specimens of this species from the locality on Kunda Brook are mcluded in the collections of the United States National Musemn. 332 CA^ffiKIAN BRACIilOPODA. in Miclcuntzia pretiosa Walcott. The outline of the valves appears to have been ovate to sub- circular and the ventral valve moderately convex. The shell is phosphatic or chitinous and built up of three principal layers. The outer laj^er is tliin, and thicldy set with minute pustules or granules that give the surface a roughened appearance. Wlien the outer layer is exfoliated, wliich is usually the case, the jioiddle layer presents a smooth, shining surface that is marked by a few concentric striae and numerous fine radiating striae, between which many minute punctse occur. The inner layer shows minute, irregular, serpentine, rounded ridges, perforated by vertical canals or punct£e. An interior of a ventral valve shows the lines of advance of the anterolateral muscle scars. The largest shell indicated on the surface of the siliceous shale has a length and width of 12 mm. The generic reference of this species is based on the apex of the ventral valve and the structure and character of the shell. Formation and locality. — Lower Cambrian: (53) Sandstones in the lower portion of 3d of the Waucoba Springs section [Walcott, 1908f, pp. 187 and J-88], 1 mile (1.6 km.) east of the Saline Valley road, about 2.5 miles (4 km.) east- northeast of Waucoba Springs, Inyo County, California. (174c) Sandstones on small hill in the salt flat, 1 mile {1.6 hm.) northeast of Silver Peak Mill, Silver Peak quad- rangle { U. 8. Geol. Survey), Esmeralda County, Nevada. MiCKWITZIA PEETIOSA Walcott. Plate VI, figure 2. Michwitzia pretiosa Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, pp. 54-55, PI. VII, fig. 2. (Described and discussed as below as a new species. Fig. 2 is copied in this monograph, PI. VI, fig. 2.) Tliis species is founded on a single specimen of a ventral valve. It has a length of 7 mm., width 6.5 mm. Outline subcircular, slightly convex; apex curved over toward the posterior margin and projecting beyond it. False area short and obscure. Surface marked by radiating raised lines that at the front margin show six in a distance of 2 millimeters. Fine papillfe are thickly scattered over the surface, with a tendency to follow concentric lines of growth on some portions of the shell, and on others they appear on low, narrow, serpentine ridges, as in M. monilifera (Linnarsson). A few large punctse are scattered here and there over the surface. Inner surfaces and layers of shell unknown. This beautiful shell differs in the details of its surface from M. monilifera; it is also less convex, and the apex is nearer the posterior margin. Formation and locality. — Lower Cambrian: (390j) Eophyton sandstone at Lugn^s, 8 miles (12.8 km.) south- southwest of Mariestad, Province of Skaraborg, Sweden. MiCKWITZIA ? sp. undt. Lingula hawTcei ? Bornemann [not Eouault], 1891, Nova Acta Acad. Cses. Leop.-Carol. Germanicae Naturae Curiosoruni, Bd. 56, No. 3, p. 439, PI. XIX, figs. 19-20. (Characterized and discussed in German.) Bornemann describes and illustrates some large shells 3 centimeters or more in diameter from the Olenofsis beds, wliich he states are characterized by a somewhat quadrangular outline and faint sinus and resemble Barrande's "Lingula feistmanteli." I am inclined to compare this form with the large compressed casts of Mickwitzia monilifera and to make a tentative reference to the genus Miclcwitzia. The shell is certainly not Lingula rouaulti Salter. Formation and locality. — Middle? Cambrian: (354a [Bornemann, 1891, p. 439]) in grayish-white quartzitic sandstones in the valley of Gutturu Sartu, island of Sardinia, Italy. Genus MICROMITRA Meek.a [^cK/idi-, small; and mitra, a hat.] Not Iphidea Baly, 1865, Entom. Monthly Magazine, vol. 2, p. 127. (Proposed for a genus of Coleoptera.) Iphidea Billings [not Baly], 1872, Canadian Naturalist, 2d ser., vol. 6, No. 4, pp. 477^78. (Type species ("Iphidea bella ") described and discussed and ' ' Iphidea " mentioned as a new genus. The reference is copied in this mono- graph under Micromitra (Paterina) bella, p. 345.) a The synonymy for this genus does not give a complete record of the various genera under which the species now included in Micromitra were formerly placed; it includes only those references in which the genus is discussed or described. For the salce of completing the record the remaining mere generic references are here listed: Kutorgina Linnarsson [1876, p. 25]. Kutorgina Hall and Whitfield [1877, p. 207). Kutorgina Walcott [1884b, p. 20]. Kutorgina Matley [1902, p. 146]. Kutorgina Gronwail [1902, p. 40]. PATERINID^. 333 Micromitra Meek, 1873, Sixth Ann. Rept. II. S. Geol. and Geog. Survey Terr, for 1872, p. 479. (Suggests Micromilm as a new generic name for " Ipkidea (.?.?) scuZpiiKs" if that species should prove to belong to a new genus. Thia refer- ence is quoted in this monograph, p. 334.) Ipkidea Billings, 1874, Geol. Survey Canada, Paleozoic FossUs, vol. 2, pt. 1, p. 76. (Copied from BiUings, 1872b, pp. 477^78.) Ipkidea Billings, Linnarsson, 1876, Bihang till K. svensk. Vet.-Akad. Handl., Bd. 3, No. 12, p. 26. (Mentioned in English in the discussion of "Iphidea ornatella.") Ipkidea Billings, Dall, 1877, Bull. U. S. Nat. Mus., No. 8, p. 39. (Mentioned.) Ipkidea Billings, Waloott, 1886, Bull. U. S. Geol. Survey No. 30, pp. 100-101. (Copies the original description, BU- lings, 1872b, pp. 477^78, of the type species {"Ipkidea hella") and discusses genus.) Kuiorgina Waloott (in part), [not Billings], 1886, Idem, pp. 101-102. (Genus Kutorgina described, but descrip- tion also includes reference to specimens now referred to Micromitra, Micromitra (Paterina), and Micromitra (Iphidella).) Ipkidea Billings, Oehleet, 1887, Manuel de conchyliologie, by Fischer, p. 1270. (Described in French.) f Iphidea Billings, Hall and Clarke (in part), 1892, Eleventh Ann. Kept. State Geologist New York for 1891, p. 249 (Described, but accompanied by figures of specimens belonging with the subgenus Paterina.) f Iphidea Billings, Hall and Clarke (in part), 1892, Forty-fifth Ann. Rept. New York State Mus. for 1891, p. 565 (Copy of preceding reference.) Kutorgina Walcott, Hall and Clarke (in part), 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, pp. 90-94 (Copies Walcott's description, 1886b, pp. 101-102, and discusses genus, but description and discussion also include reference to specimens now referred to Micromitra, Micromitra (Paterina), Micromitra {Iphidella), Pro- tortkis, and Billingsella.) Ipkidea Billings, Hall and Clarke, 1892, idem, pp. 97-98. (Copies the original description, Billings, 1872b, pp. 477-478, of the type species ("Ipkidea bella") and discusses genus.) Ipkidea Billings, Waloott (in part), 1897, Proc. U. S. Nat. Mus., vol. 19, pp. 707-711. (Discussed. The genus includes species now referred to Micromitra, Micromitra (Paterina), and Micromitra (Iphidella).) Iphidea BUlings, Schuchert (in part), 1897, Bull. U. S. Geol. Survey No. 87, p. 233. (Merely refers Micromitra and Paterina to Ipkidea.) Iphidea Billings, Walcott, 1899, Mon. U. S. Geol. Survey, vol. 32, pt. 2, pp. 447^48. (Mentioned in discussion of "Ipkidea sculptilis.") Iphidella Walcott (in part), 1905, Proc. U. S. Nat. Mus., vol. 28, p. 304. (Merely proposed to replace Ipkidea, but includes reference to specimens belonging with Micromitra, Micromitra (Paterina), and Micromitra (Ipkidella) .) Paterina (Micromitra) (Meek), Schuchert, 1905, Am. Jour. Sci., 4th ser., vol. 19, p. 329. (Suggests that Micromitra be used in a subgeneric sense, under Paterina, for the forms typified by Micromitra sculptilis.) Not Ipkidea Grabav and Shimer, 1907, North American Index Fossils, vol. 1, p. 201. (Described, but the species placed under it belong with the subgenera Paterina and Ipkidella.) Micromitra Meek, Walcott, 1908, Smithsonian Misc. CoU., vol. 53, No. 4, PI. XI, and pp. 142 and 143. (Classification of genus.) Ventral valve conical (Micromitra (Paterina) etJieridgei (Tate), PL III, fig. 10) to depressed conical (if. (P.) labradorica (Billings), PI. II, fig. 2), with the beak curving more or less over a false area which is divided niidway by a triangular fissure that may be covered almost entirely (M. (P.) superba (Walcott), PI. II, fig. 1) or only in part (Micromitra (Iphidella) ornatella (Lin- narsson) , PI. Ill, fig. 6) by a convex pseudodeltidium. Dorsal valve slightly to moderately convex. Beak small and usually curved a little over a low area (Micromitra pealei (Walcott), PI. Ill, fig. 3e') that has a rather broad pseudodeltidium. Surface marked by concentric lines of growth and fine radiating striae (Micromitra (Paterivu) labradorica (Billings)) ; crenulated concentric striae that give a more or less distinctly crenu- lated appearance to the surface (Micromitra sculptilis (Meek)); and strongly crenulated concen- tric stride forming a network of raised, obliquely arranged lines that divide the surface into minute pits (Micromitra (Iphidella) pannula (White)). Shell substance corneous. Shell built up of thin layers or lamellae that are more or less obhque to the outer surface. Very little is known of the interior of the valves. The ventral valve of Micromitra (Pater- ina) labradorica (Billings) (PI. II, fig. 2c) has a few lines or ridges that radiate from the beak very much as in Kutorgina (PI. V, fig. 1). The dorsal valve also shows radiating ridges (Micro- mitra (Iphidella) ornatella (Linnarsson) PL III, fig. 6d), and in addition an exfoliated shell of M. (I.) pannula ophirensis Walcott shows a median ridge, the base of the main vascular sinuses, and two central muscle scars (PL IV, fig. 4e). Type. — Iphidea (??) sculptilis Meek [1873, p. 479]. 334 CAMBRIAN BRACHIOPODA. Meek's original reference to Micromitra [1873, p. 479] is as follows: It is quite probable that when specimens showing clearly all the characters of this shell can be examined it will be found to belong to an undefined genus, either of the Brachiopoda or some other group. In this case I would propose for this genus the name Micromitra. The type specimen labeled by Meek in 1873 as Iphidea (Micromitra) sculptilis is in the col- lections of the United States National Museum (Catalogue No. 7864). The label is in Meek's handwriting and firmly attached to the specimen of rock containing the shell. The description of the shell referred to Iphidea {f?) sculptilisMeek [1873, p. 479] is that of the ventral valve. While no generic description is given and the specific description is incom- plete, we are necessitated by the present rules of nomenclature to accept the name Micromitra, since Iphidea, as proposed by Billings [1872b, p. 477], was preoccupied by Baly in 1865. When away, engaged in field work, I accidentally discovered that the genus Iphidea was first used by Baly in 1865. I then put the name Iphidella in some manuscript notes and by oversight this name was published [Walcott, 1905a, p. 304]. Schuchert [1905, p. 329] called attention to its being a synonym of Micromitra and Paterina. This is shown in my synonymy of the genus Iphidea [1897b, p. 707]. I now use Iphidella as a subgenus of Micromitra. Billings's description of the genus Iphidea and that of the type species were combined. At the time of my study of Kutorgina and Iphidea [Walcott, 1886b, p. 100] I did not agree with Billings in his reference of "Obolus labradoricus" to Iphidea [Billings, 1874, p. 76]. Since that time I have collected more material representing this group of shells, and from its study have come to the conclusion that Billings was correct in referring "0. lahradoricus" to his genus Iphidea. The ventral valve of "0. lahradoricus" has a narrow false area of the same type as Micromitra (Paterina) hella (Billings), and the characteristic pseudodeltidium is clearly shown in a section, and it is known to occur in Micromitra sculptilis (Meek), Micromitra (Iphidella) ornatella (Linnarsson) , and M. (I.) pannula (White). The extreme development of the false area and pseudodeltidium is found in M. (P.) superha (Walcott), from the Middle Cambrian "Tonto" sandstone of the Grand Canyon of the Colorado. In this form the ventral valve is broadly conical, and the large pseudodeltidium projects backward at an angle equal to the slope from the apex to the front. In Micromitra (Paterina) hella the false area slopes more abruptly downward and in Micromitra (Iphidella) ornatella it is nearly vertical, the pseudodeltidium being much shorter and projecting but a short distance beyond the area. The slope of the area of M. (I.) ornatella is essentially the same as that of Micromitra (Paterina) lahradorica swantonensis (Wal- cott), which is the type of Beecher's genus Paterina. (See p. 344.) In some specimens of the latter species the beak projects so that the slope of the area carries it forward to a considerable distance under the beak. This is also true of Micromitra (Iphidella) pannula. The presence of an apical foramen in Micromitra (Paterina) hella and Micromitra (Iphidella) ornatella would separate those species from the Paterinidae, but from a careful study of all the evidence attainable I am led to question the presence of a true apical foramen in either species. Unless there are other characters than those shown by the false area and pseudodeltidium and the angle at which they slope, it will be impracticable to generically separate Micromitra (Pater- ina) hella and M. (P.) lahradorica and the other species mentioned. In his original description, Billings [1872b, p. 478] says: In the specimen above figured there ia an aperture in the beak, but in another there is no appsarancs whatever of a perforation. In a fine series of Micromitra (Paterina) hella from the Lower Cambrian,, south of Emigs- ville, York County, Pennsylvania, the characteristics of the genus and species are strikingly well shown. In none of the specimens is there in the ventral valve an indication of an apical pedicle opening. The dorsal valve is slightly elevated, and in the half-dozen well-preserved specimens no trace has been observed of any false area or pseudodeltidium; but in Micromitra (Iphidella) pannula the false area is even more clearly defined than in the ventral valve, and the pseudodeltidium is present as a depressed concave covering of more than one-half of the triangular space inside the narrow area on each side. The area on the dorsal valve has also been observed in M. (I.) ornatella (Linnarsson) and Micromitra (Paterinn) lahradorica (Billings). PATERINID^. 335 Linnarsson [1876, p. 25], in describing Micromitra {IpMdella) ornatella, speaks of the pres- ence of a minute foramen; but, after the study of several finely preserved ventral valves from the Paradoxides beds of Andrarum, Sweden, I am led to believe that what he considered to be an apical foramen is a depression in the apex of the shell on the incurved beak which was present in one of the embryonic (nepionic) stages and was subsequently lost. Tliis would involve the crowding out, as it were, of the pedicle posteriorly, the only evidence of its presence in the adult being the narrow, slightly depressed slit at the apex of the valve in some specimens. The pedicle in the adult shell is protruded between the two valves and separated from the scar of the embryonic pedicle slit by the growth of a pseudodeltidium. The examination of the somewhat closely allied form, Micromitra {IpJiidella) pannula (White), shows the presence in some specimens of an apical depression, and its absence in others. In Micromitra (Paterina) superia (Walcott), still more closely approaching the type, M. (P.) hella (Billings), in external appearance, there is no trace of an apical slit. In Micromitra (Paterina) crenistria (Walcott) , which is associated with M. (P.) superba, the apex is rounded, while in the somewhat similar but distinct form, M. pealei (Walcott), from the Gallatin River valley of Montana, the apical slit is as clearly shown as in Micromitra {IpMdella) ornatella (Linnarsson), but there is no apical foramen. Hall and Clarke [1892c, p. 97] illustrate a specimen of Micromitra {Paterina) hella showing an apical foramen, but in the description of PI. TV, fig. 8, the statement is made that the foramen is not altogether distinct in the specimen. The systematic position of the genus Micromitra appears to be in the Atremata of Beecher [1891, p. 354], with possible characters that nearly place it in the Protremata. The presence of an obscure apical furrow in front of the apex of Micromitra {Paterina) hella (Billings), Micro- mitra {IpMdella) ornatella (Linnarsson), and in some specimens of Micromitra pealei (Walcott) tends to support the view that tlie pedicle was apical in its early stages. We also have to con- sider the area of what appears to be the dorsal valve of Micromitra {IpMdella) pannula. In this species there is a rather deep convex pseudodeltidium in the conical valve and a clearly defined, depressed pseudodeltidium on the flat valve between the sides of the narrow false area. There is also present on the latter valve a narrow median groove extending from the apex to the posterior margin of the pseudodeltidium; it is similar in appearance to the pedicle groove of the ventral valve of Oholus and RMnoholus. This suggests that the flat valve may be the pedicle valve, but the presence of a scar of the embryo pedicle opening on the conical valve is opposed to such an interpretation. It may be urged that Micromitra is a true atrematous genus, the pedicle never having been inclosed and the slit on the ventral valve being only a depression without special significance. This may be so, but the impression it conveys to me is that the slit indicates a pedicle opening which existed near the apex of the ventral valve at an early stage in its growth, but which was subsequently closed, the pedicle continuing to protrude between the valves. Whiteaves \\Tote me, under date of July 2.3, 1896, that with the exception of the specimen wliich is referred in tlus monograph to Micromitra {Paterina) logani (see pp. 345 and 350), there were no specimens or electrotypes of the types of Micromitra {Paterina) hella (Billings) in the collections of the Geological Survey of Canada, nor of the closely allied species of the same genus from Topsail Head, mentioned by BiUings [1872b, p. 478]. Under the circumstances nothing can be done but to decide from Billings's description and figure [1872b, p. 477] the characters of the species, and refer to the species the form that can best be identified with the description and figure, as its typical representative. This appears to be the form from the Lower Cambrian limestone of York County, Pennsylvania. (See pp. 345 and 350, and PI. II, figs. 1 and Ic.) Ornamentation of the surface. — One of the most noticeable characters is the surface orna- mentation. The type species of Micromitra {M. sculptilis (Meek), PI. Ill, figs. 5, 5a-c) has on some specimens (PI. Ill, figs. 5c, 5d) concentric fines similar to those on the less ornamented forms of the genus, as represented by Micromitra {Paterina) labradorica (BiUings), and on other specimens a weU-defined series of radiating ridges of varying number, width, and strength (PI. Ill, figs. 5, 5a, and 5c). It was on account of the surface produced by the concentric lines crossing the radiating ridges that the specific name sculptilis was proposed. 336 CAMBRIAN BRACHIOPODA. Micromitra sculftilis (Meek), the type of group A {Micromitra Meek), is therefore inter- mediate in surface charactere between the concentricall}^ striated forms of group B {Paterlna Beecher) and the network ornamentation of group G {IpTiidella Walcott), though some exam- ples of the latter group have both the A and G types of surface on the same shell. The species with the inteimediate type of surface may be grouped under the genus Micromitra, as follows: Micromitra alabamaensis (Walcott) Middle Cambrian. haydeni Walcott Do. nisus (Walcott) 'Do. pealei (Walcott) Do. pusilla (Linnareson) Do. scotica Walcott Lower Cambrian. sculptilis (Meek) Middle and Upper Cambrian. sculptilis endlichi Walcott Middle Cambrian. zenobia Walcott Do. Micromitra {Paterina) labradoricaswantonensis (Walcott) and M. {P.) bella (Billings) represent the second type (B), whose surface is formed of simple concentric striae and lines of growth. On the basis of surface characters tliis group is given a subgeneric value, as suggested by Schuchert [1905, p. 329], and the name Paterina of Beecher [1891, p. 345] is adopted.*^ The group includes: Micromitra (Paterina) bella (Billings) Lower Cambrian. crenistria (Walcott) Middle Cambrian. etheridgei (Tate) Do. labradorica (Billings) Lower Cambrian. orientalis (Walcott) Do. swantonensis (Walcott) Do. utahensis (Walcott) Middle Cambrian. var. undt Lower Cambrian. logani (Walcott) Middle Cambrian. major (Walcott) Lower Cambrian. phillipsi (Holl) Upper Cambrian. prospectensis (Walcott) '. Lower Cambrian. stissingensis (Dwight) Middle Cambrian. stissingensis ora Walcott Do. stuarti Walcott Do. superba (Walcott) Do. undosa (Moberg) Lower Cambrian. wapta Walcott Do. williardi Walcott Do. Micromitra (Iphidella) ornatella (Linnarsson) and M. (7.) pannula (White) represent the third type (C), whose surface is formed by the union of the crenulated striae so as to form a fine network of raised obliciuely arranged lines that divide the surface into minute pits that give the impression of finely woven cloth. For the species with this ornamented surface IpMdella Walcott [1905a, p. 304] is used in a subgeneric sense. This includes: Micromitra (Iphidella) louise Walcott Lower Cambrian. nyssa Walcott '. Middle Cambrian. ornatella (Linnarsson) Do. pannula (A\1iite) Lower and Middle Cambrian. maladensis (Walcott) Middle Cambrian. ophirensis (Walcott) Do. StratigrapMc distribution. — The genus ranges from low down in the Lower Cambrian through the Middle Cambrian, and there are two species in the Upper Cambrian. Of the Lower Cambrian species, M. (I.) pannula (White) passes up into the central portion of the Middle Cambrian in the Marjum limestone of the House Range section, Utah. Micro- mitra sculptilis (Meek) occurs abundantly in the central portion of the Middle Cambrian and has also been found in the Upper Cambrian Dunderberg shale of the Eureka district, Nevada. Micromitra {Iphidella) jjannula ophirensis (Walcott) has a range of 2,370 feet (722.4 m.) in the House Range section of Utah, occurring in the Middle Cambrian at horizons 220, 2,075, and 2,590 feet (67, 632.5, and 789.4 m.) above the quartzitic sandstones of the Lower Cambrian. o It is therefore impossible to use the type of the preoccupied genus Iphiiea, MicromitTa {Paterina) bella, as the type of this subgenus, as Beecher founded it on " Obolus lahradoricus." (See p. 344.) paterinidJ:. 337 At Ophir, in the Oquirrh Range, it is at the horizon of the Pioche fauna, or near the base of the Middle Cambrian. The table in the introduction gives a summary of the numbers and the range of the genus by species and varieties. (See p. 99.) MiCROMITKA -ALABAMAENSIS (Walcott). Plate II, figures 5, 5a-c. IpMdea alabamaensis Walcott, 1897, Proc. U. S. Nat. Mus., vol. 19, pp. 713-714, PI. LIX, figs. 5, 5a-b. (Discussed somewhat as below as a new species. The specimens represented by figs. 5, 5a-b are redrawn in this monograph PL II, figs. 5, 5a, and 5c, respectively.) In following the Lower Cambrian- rocks southward -from Vermont, the first type of Micromitra met with is M. stissingensis (Dwight), which occui-s in the Mddle Cambrian of Dutchess County, New York. This is fairly well distinguished by its surface character from Micromitra (Paterina) labradorica (Bilhngs) and its variety swantonensis (Walcott), but at the next locahty to the south in eastern Tennessee, 4 miles (6.4 km.) north of Rogersville, in the Rogei-sviQe shale of the Mddle Cambrian, was found a form that is practically identical with the northern species or its variety, so far as it is possible to compare specimens preserved in limestone with those preserved in shale. A species of the same general form also occurs in the Mddle Cambrian shales of the Cowan Creek section, Cherokee Countj^, Alabama. There is, however, a difference in the surface strife that distinguishes it from M. (P.) labradorica, M.' (P.) labradorica swantonensis, and M. (P.) stissingensis. It is the tendency to crenulation of the striae in nearly all the specimens that have been examined. This, in extreme cases, goes so far as to approach the surface so characteristic of Micromitra (IpJiidella) pannula (White). The form can not well be identified wath the closely related M. (P.) labradorica (Bilhngs) or its variety swantonensis (Walcott) or M. (P.) stissingensis (Dwight) on account of these pecuhar surface characters, and the name M. alabamaensis was proposed for it. In the general form of the valves this species resembles M. (P.) labradorica and 21. (P.) stissingensis. So far as kno\vn the only specific difference is ia the surface character, which allies it with Micromitra sculptilis (Meek) . The convexity of the valves is unknown, owing to the compression of the shells in the shale, and we have no information of the area or pseudo- deltidium. Shell substance corneous. Formation and LOCALrry. — Upper Cambrian: (94o) Limestone at base of dolomite, 0.25 mile (0.4 km.) beyond Givens Ford, Cowan Creek, about 8 miles (12.8 km.) southeast of Center, Cherokee County, Alabama. Middle Cambrian : (90x and 94a) In and attached to the outer surface of siliceous nodules in the Conasauga (" Coosa ") shale, Coosa Valley, east of Center; (95a) shales on Spring Creek, near the old tram crossing north of Center road, Cowan Creek valley, southeast of Center; and (94) shales 0:25 mik {0.4 km.) beyond Steel Ford, Coioan Creel, about 8 miles {12.8 km.) southeast of Center; all in Cherokee County, Alabama. (121a) Shales on road leading from southeast of Harlan Knob to Amis post oflice; (124) shales (NoHchucky?) overlying the limestone which rests on the Rogersville shale, on Big Creek, southeast of Harlan Knob; (123) upper part of Maryville Umestone, on Big Creek, southeast of Harlan Knob; and (121) Rogersville shale, road just east of Harlan Knob; all about 4 miles (6.4 km.) northeast of Rogersville [Keith, 1905, p. 4, and areal geology sheet], Hawkins County, Tennessee, (14a) Sandstone of the Rome formation, along First Creek Gap, 4 miles (6.4 km.) north-northeast of Knoxville [Keith, 1905, areal geology sheet], Knox County, Tennessee. Micromitra HAYDENi Walcott. Text figures 20A-D, page 338. Micramitrahaydeni Waj.cott, 1908, Smithsonian Misc. Coll., vol.53. No. 3, pp. 55-56, PI. VII, figs. 3 and 3a. (Described and discussed as below as a new species. Figs. 3 and 3a are copied in this monogi-aph as figs. 20A and 20B'.) Ventral valve subcorneal, with a minute beak arching slightly over a strong, arched pseudo- deltidium which, is about one-half as long as the height of the valve. Cardinal slope rounded; a slight angle is indicated by a. fine where the concentric siu-face striee bend inward toward the pseudodeltidium across the narrow area ; a sharp angle is formed where the convex pseudodeltid- ium rises abruptly from the area. 62667°— VOL 51, pt 1—12 22 338 CAMBRIAN BRACmOPODA. -X Dorsal valve moderately convex, most elevated at the small imibo just in advance of the marginal minute beak ; area very low and narrow, and without trace of pseudodeltidium so far as now kno\vn. Surface marked by fine, concentric, slightly undulating, threadlike strise and a varying number of irregular, more or less interrupted, narrow, depressed, roimded radiating ridges; these ridges are usually most numerous at the central portions of the valves. The concentric strise extend across the narrow area and arch over the pseudodeltidium, where they are finer and crowded together so that all the strise between the apex and the front margin are com- pressed in about one-half the distance on the pseudodeltidium. The adult ventral valve is about 4.5 mm. in length by 5 mm. in width and 2.5 mm. in height, with a pseudodeltidium 1.3 mm. in length. A dorsal valve 2 mim. in length has a height of about 0.5 mm. at the umbo. The shell is rather thick for a species of this size, and it is built up of several thin layers or lamellse. Observations. — Micromitra Jiaydeni differs from the nearest related species, M. sculptilis (Meek), in having a strong convex pseudodeltidiimi, less elevation of the ventral valve, and a thicker shell. Micromitra haydeni occurs near the base of the Middle Cambrian and M. sculptilis about 2,000 feet (610 m.) higher in the section of the Cambrian rocks of Utah and southern Idaho. The specific name is given in honor of Dr. F. V. Hayden, geologist and explorer, under whose charge the geology of this region was first studied. Formation and iocality.— Middle Cambrian: (54s) Dark blue-gray Lamgston limestone [Walcott, 1908f, p. 198], just above the Cambrian quartzitic sandstones, north side of Twomile Canyon, near its mouth, 2 miles (3.2 km.) south- east of Malade, Oneida County, Idaho. Micromitra nisus (Walcott). Plate II, figure 10. Iphidella nisus Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 305. (Described and discussed as below as a new species.) Ventral valve rather low, with the apex overhanging the posterior margin. Surface marked by very fine lines of growth with still finer bands of strise between them. About 10 very fine radiating ridges extend from near the apex to the front and lateral margins. This little shell is represented by a single specimen of the ventral valve. The associated faima includes fragments of Olenellus. I was at first inclined to refer this shell to Micromitra sculptilis (Meek) or M. pealei (Wal- cott), but the overhanging apex and strongly marked surface and the fact that there is an interval of 2,000 miles between the localities of the species led me to separate them. Strati- graphically the two latter species occur in the Middle Cambrian and M. nisus in the Lower Cambrian. I do not think the two forms should be included in one species. Formation and locality.— Lower Cambrian : (2r) In a limestone bowlder in a conglomerate, in a railroad cut 2 miles (3.2 km.) west of Bic railway station, Rimouski County, Quebec, Canada. FiGUKE 20.— Micromitra haydeni Walcott. A, Top view of ventral valve (U. S. Nat. Mus. Cat. No. 61437a). B, B', Side and back views of a ventral valve (U. S. Nat. Mus. Cat. No. 5H37b). C, Exterior of dorsal valve (U. S. Nat. Mus. Cat. No. 51437c). D, Dorsal valve (U. S. Nat. Mus. Cat. No. 51437d). The specimens represented are from Locality 54s, Middle Cambrian lime- stones, near Malade, Idaho. Figures 20A and 20B' are copied from Walcott [IQOSd, PI. VII, figs. 3 and 3a]. Figure 20A represents the type specimen. PATEEINIDiE. 339 MiCROMITRA PEALEI (Walcott). Plate III, figures 3, 3a-e. Iphidea pealei Walcott, 1897, Proc. U. S. Nat. Mus., vol. 19, pp. 712-713, PI. LIX, figs. 3, 3a-c. (Described and dis- cussed as below as a new species. The two specimens represented by figs. 3, 3a-b, and 3c are redrawn in this monograph, PI. Ill, figs. 3, 3a-b, and 3c, respectively.) Ventral valve subconical, beak slightly incurving over the pseudodeltidium. Cardinal slope flattened to form a narrow false area, which is clearly defined from the curvature of the shell by a slightly elevated tlireadlike ridge. Pseudodeltidium comparatively narrow, strongly convex, and arched below. The strise of growth cross the false area and arch over the delthyrium. Dorsal valve moderately convex, and without any special characteristics to distinguish it from the same valve in Micromitra {Paterina) iella (Billings), M. (P.) superha (Walcott), and 21. (P.) lahradorica (Billings). Surface marked by fine concentric striae and lines of growth that are usually plain, but in some examples are shghtly crenulated. In such instances fine radiating hues or strias are also shown. Shell substance corneous. In the most perfectly preserved specimens there is a slight furrow or depression near the apex of the ventral valve, but there is no trace of a perforation or apical opening. Tliis species approaches M. sculptilis (Meek) in some examples of the ventral valve. It differs mainly in the narrow pseudodeltidium and the character of the surface markings. It might be considered as a form intermediate between M. (P.) heUa (Billings) and M. sculptilis (Meek). The specific name was given in honor of Dr. A. C. Peale, of the Hayden Survey, who col- lected the type specimen. Formation and locality. — Middle Cambrian: (4ii) Limestone about 325 feet (99.1 m.) above the unconformable base of the Cambrian in divide at the head of Jackson Creek (locally known as Sheep Creek), a creek flowing into Jackson Lake about 0.5 mile (0.8 km.) south of its northwestern corner, Teton Mountains, Grand Teton quadrangle (U. S. Geol. Survey), Uinta County, Wyoming. (159) Limestones north of West Gallatin ( Gallatin) River, Gallatin County; (302) limestone east of Gallatin River, above Gallatin, Gallatin County; (4p) about 225 feet (68.6 m.) above base of Cambrian in limestones interbedded in Flathead shales of Peale [1893, p. 21], on the north side of West Gallatin (Gallatin) River, 2 miles (3.2 km.) north- east of Logan, Threeforks quadrangle (U. S. Geol. Survey), Gallatin County; (155a) limestone north of East Gallatin River, near Hillsdale, Threeforks quadrangle ( U. S. Geol. Survey), Gallatin County; (th.) about 375 feet (114.3 m.) above base of Cambrian in limestone interbedded in the Flathead shales of Peale [1893, p. 21], 1 mile (1.6 km.) north of the junction of East Gallatin and West Gallatin (Gallatin) rivers, 4 miles (6.4 km.) east-northeast of Logan, Threeforks quadrangle (U. S. Geol. Survey), Gallatin County; (5f and 340) limestone interbedded in the Wolsey shale [Weed, 1900, p. 285], in Meagher County on road to Wolsey, south of the divide at the head of Sawmill Creek, and about 12 miles (19.3 km.) south of Neihart, Little Belt Mountains quadrangle (U. S. Geol. Survey), Cascade County; (4x) limestone interbedded in the Wolsey shale [Weed, 1900, p. 285], at the base of a butte in Belt Park, about 6 miles (9.6 km.) northwest of Neihart, Little Belt Mountains quadrangle (U. S. Geol. Survey), Cascade County; and (9h) limestone on Beaver Creek, 5 miles (8 km.) north of York, about 8 miles (12.8 km.) north of Canon Ferry, Big Belt Mountains, Fort Logan quadrangle (U. S. Geol. Survey), Meagher County; all in Montana. (74) Sandstone about 300 feet (91.4 m.) above the base of the Tonto group, at the head of Nunkoweap Valley, Grand Canyon of the Colorado, Arizona. Micromitra pusilla (Linnarsson). Plate III, figures 2, 2a-c. Kutorgina cingulata pusilla Linnars.son, 1876, Bihang till K. svensk. Vet.-Akad. Handl., Bd. 3, No. 12, p. 25, PI. IV, figs. 53 and 54. (Described as below, and discussed in English, as a new variety.) Kutorgina cingulata Walcott (in part) [not Billings], 1886, Bull. U. S. Geol. Survey No. 30, pp. 102-104. (Speci- mens now referred to Micromitra pusilla were included with the specimens representing Kutorgina cingulata when this description was written.) Kutorgina cingulata pusilla Linnarsson, Matley, 1902, Quart. Jour. Geol. Soc. London, vol. 58, pt. 1, pp. 146-147 figs. 19 and 20, p. 147. (Discussed from a new locality.) Kutorgina cingulata pusilla Linnarsson, Gronwall, 1902, Danmarks Geol. Unders0gelse, Rsekke 2, No. 13, pp. 40-41. (Discussed in Norwegian.') 340 CAMBRIAN BRACHIOPODA. Linnarsson [1876, p. 25] gives the following description of the dorsal valve of this species: Shell small, transversely oval, broadest about the middle. Hinge-line straight, shorter than the width of the shell; cardinal angles rounded. Shell substance apparently corneous. Surface marked with numerous sharply marked, concentric lines of growth. Length, 3 mm.; breadth, 4 mm. In some material received from Andrarum, Sweden, I found what appear to be the ventral and dorsal valves of this species associated with Micromitra (IpJiidella) ornatella (Linnarsson) and Acrotreta socialis von Seebach. The ventral valve shows a well-defined false area on each side of a triangular opening. The broken edge of the pseudodeltidium is shown on the side of the upper end of the fissure, but its form and depth can not be determined. This species is related to Micromitra {Paterina) labradorica (Billings), differing from it in having a less elevated ventral valve, radiating ridges on the surface, and being more uni- formty smaller in size. It is evidently a rare form, as only three specimens were met with in brealdng up a large quantity of rock. Formation AND LOCALITY. — Middle Cambrian: (8w) Limestones of the ParadoxiWes/orcMommm zone, at Andra- rum, 20 miles (32.2 km.) northwest of Simi-ishamn, Province of Christianstad ; (320f) limestone at Andrarum, 20 miles (32.2 km.) northwest of Simiishamn, Province of Christianstad; and (320u [Linnarsson, 1876, p. 25]) strata with Agnostus Ixvigatus at Ostra Rynninge, in Nerike; all in Sweden. (16h) Limestones of the Paradoxides forchhammeri zone at Borregaard; and (16j) limestones of the Paradoxides forch- hammeri zone at Laesa8.; both on Bornholm Island, Denmark. Matley [1902, p, 146] has identified this species from the following locality:" Upper Cambrian: (304b) Lower part of the "^Vhite Leaved Oak" shales (the zone of Polyphyma), Malvern Hills, between Herefordshire and Worcestershire, England, Micromitra scotica n. sp. Text figures 21A-C. Ventral valve moderately convex, transverse in outline. Beak almost apical, slightly in Cardinal slopes flattened to form a false area that is almost as wide as the greatest width of the shell. Pseudodeltidium narrow and arch- ing somewhat above the plane of the margin of the shell. Dorsal valves unknown. Surface marked by rather coarse concentric striae and radiat- ing ridges. The concentric striae cross the false area and the pseu- dodeltidium. Ohservations.—ThSs species ap- pears to be most closely related to FIGDRE21.— iV/(crom!«mMO/ico n.sp. A, Type specimen, a ventral valve, X4, from Local- MicTOmitra 'pusillo, (LiimarSSOn), ity 316d, Lower Cambrian shale on Meall k Ghiubhais, Ross-shire, Scotland (U. ^■ij.-j.u r+* '1 if fl^ Nat. Mus. Cat. No. 58310). B, B', B", Top, side, and back^^e\vs of aventral valve, XS, OUt IS tO DC CllStingUlSliea trom. tnat from Locality 316d, Lower Cambrian shale on Meall fi, Ghiubhais, Ross-shire, Scotland SDecieS bv reaSOn of itS loiio" nsCU- (Geol. Survey Scotland, specimen No. M2G46e). C, Top view of a crushed ventral iii-j- ii c i^i valve, X2.5, from Locality 316d, on Meall 4 Ghiubhais, Ross-shire, Scotland (Geol. dodcltlduim ailQ the tact that the Survey Scotland, specimen No. M417Sd). |^p^], j^^g j^^^. Q^rQrh&Xig the false area. The latter species occurs in the Middle Camljrian and Micromitra scotica is associated with Olenellus in Scotland. Formation and locality.— Lower Cambrian: (316d) b Localities M2646e, M2647e, and M4178d of the Geological Survey of Scotland, about 500 feet (152.5 m.) above the provisional base of the Cambrian and 75 feet (23 m.) below what is believed to be the top of the Lower Cambrian in the shales forming 5 and 6 of the section given by Peach and Home [1907, p. 414], in a small burn on the north slope of Meall A Ghiubhais, 4 miles (6.4 km.) west-northwest of the Kinlochewe Hotel, Loch Maree, Ross-shire, Scotland. advance of the posterior margui, which is nearly' straight. B a Groom [1902, p. 109] describes the locality and cites a list of the associated species. b Specimens from this locality are also included in the collections of the United States National Museum. PATERINID.E. 341 MiCEOMiTRA scuLPTiLis (Meek). Plate III, figures 5, 5a-e. IpMdea (;??) seulptilis Meek, 1873, Sixth Ann. Kept. U. S. Geol. and Geog. Survey Terr, for 1872, p. 479. (Described and discussed as a new species, and the generic name " Micromitra" proposed in case the species should prove to belong to a new genus.) Kutorgina minutissima Hall and Whitfield, 1877, U. S. Geol. Expl. 40th Par., vol. 4, pt. 2, pp. 207-208, PL I, figs. 11 and 12. (Described and discussed as a new species. The specimens represented by figs. 11 and 12 are redrawa in this monograpb, JPl. Ill, figs. 5b and 5c, respectively.) Kutorgina seulptilis (Meek), Walcott, 1884, Men. IT. S. Geol. Survey, vol. 8, p. 20, PL I, figs. 7, 7a-b, PL IX, fig. 7. (The three specimens represented in PL I, figs. 7 and 7a, PL I, fig. 7b, and PL IX, fig. 7, are redrawn in this monograph, PL III, figs. 5, 5b, and 5c, respectively.) IpMdea seulptilis Meek, Schuchert, 1897, Bull. U. S. Geol. Survey No. 87, p. 235. (Merely goes back to original generic reference.) IpUdea seulptilis Meek, Walcott, 1899, Mon. U: S. Geol. Survey, vol. 32, pt. 2, pp. 447-448, PL LX, figs. 5, 5a-c. (Discussed. The specimen represented by figs. 5, 5a-c is redrawn in this monograph, PL III, fig. 5a.) Iphidella seulptilis (Meek), Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 308. (Merely changes generic reference.) In the descriptiou of IpMdea {??) seulptilis, "Meek [1S73, p. 479] decided that as the shell had a very narrow, slightly flattened margia on each side, representing a false area, and that as there seemed to be a wide-open triangular foramen, it could be referred to the genus Acro- treta or the genus IpMdea. He was not positive that there was not a permanent pseudodel- tidium present, but assuming the absence of that structure, and tliinldng it probable that when all the characters of the shell were loiown it would be found to belong to a different genus, -either of the Brachiopoda or of some other group, he proposed for the genus the name " MicroTmtra"^ A study of the specimens of M. seulptilis collected from the same horizon, at a point not far distant from the origiaal locahty, shows the jDresence of a false area and a pseudodeltidiupa of the same type as that of Micromitra (Paterina) iella (BiOuigs). Thei'e is, however, a chfference in the two.fomis that is considered of subgeneric value. The surface of M. (P.) hella is covered with fine concentric strife and the surface of Micromitra seulptilis is marked by very fine, sharp, elevated concentric lines that coalesce or bifurcate irregular!}^, imparting a pecuharly inter- rupted wavj^ appearance that is liiglily characteristic. The variation in the surface character is continued still further in Micromitra (IpMdella) pannula (White), m which the surface is divided into miaute porelike pits by a ver}" fuie network of obhque raised lines. Under the lens the surface resembles that of finely woven cloth. The most nearly related species is Micromitra liaydeni Walcott, which has a similar surface, but the latter has a large pseudodeltidium on the ventral valve, and that valve is more depressed than in M. seulptilis. A fragmentary ventral valve from 2,500 feet (762 m.) up in the iliddle Cambrian series of the northern Wasatch Alountains appears to be a form somewhat intermediate between Micro- mitra {Paterina) erenistria (Walcott) and M. seulptilis. It has the surface of the latter except that the radiating ribs are very faint. It occurs ra the Blacksmith Fork section, east of Hyrum, Utah. Formation and locality. — Upper Cambrian: (61) Limestone in the Dunderberg shale [^''alcott, 1908f, p. 184], a little south of the Hamburg mine; and (62) limestone in the Dunderberg shale [Walcott, 1908, p. 184], in a canyon immediately north of Adams HUl; both in the Eureka district [Hague, 1892, Atlas], Eureka County, Nevada. Middle Cambrian: (302) Limestone east of Gallatin River, above Gallatin; and (302a and 302c) limestones at several places on the south side of the Gallatin Vallej-; both in Gallatin County, Montana. (302b) Limestones near Crowfoot Ridge, Gallatin quadrangle (U. S. Geol. Survey), Yellowstone National Park, Wyoming. (55n) About 1,850 feet (564 m.) above the Brigham quartzite and 2,350 feet (716 m.) below the Upper Cambrian in the limestones forming 2g of the Bloomington formation [Walcott, 1908f, p. 195], in Blacksmith Fork Canj^on, about 10 mUes (16.1 km.) east of Hyrum, Cache County, Utah. (81) Shales believed to be referable to the lower portion of the Marjum limestone [Walcott, 1908f, p. 180], found about 0.5 mile (0.8 km.) east of Antelope Springs; (3x) about 2,200 feet (670.6 m.) above the Lower Cambrian and 2,200 feet (670.6 m.) below the Upper Cambrian in the limestones forming Id of the Marjum limestone [Walcott, 1908f, p. 180], 2.5 miles (4 km.) east of Antelope Springs in ridge east of Wheeler Amphitheater; and (lOy) about 2,900 342 CAMBRIAN BRACHIOPODA. feet (884 m.) above the Lower Cambrian and 1,500 feet (457.2 m.) below the Upper Cambrian in the central part of the bed forming la of theMarjum limestone [Walcott, 1908f, p. 179], about one mile (1.6 km.) south-southwest of Marjum Pass; all in the House Range [Walcott, 1908f, PI. XIII], Millard County, Utah. (lis) Shales just above Simpson Spring, about 20 miles (32.2 km.) west-southwest of Vernon, on the stage road from Vernon to Fish Spring, Tooele County, Utah. (lOw) Shaly limestones about 5 miles (8 km.) northeast of Osceola, on the east side of the Snake Range, White Pine County; and (68) shaly limestones in upper beds of Secret Canyon shale, either in New York or Secret Canyon, Eureka district [Hague, 1892, Atlas], Eureka County; both in Nevada. Specimens that are compared with Micromitra sculptilis occur at the following locaHty: Middle Cambrian: (541) About 2,950 feet (899.2 m.) above the Brigham quartzite and 1,225 feet (373.4 m.) below the Upper Cambrian in the limestone forming le of the Bloomington formation fWalcott, 1908f, p. 194], in Blacksmith Pork Canyon, about 10 miles (16.1 km.) east of Hyrum, Cache County, Utah. MiCKOMITRA SCULPTILIS ENDLICHI Walcott. Text figure 22. Micromitra sculptilis endlichi Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, p. 56. (Characterized as below as a new variety.) This form is represented by a single specimen of a ventral valve. The surface is similar to that of Micromitra sculptilis (Meek), but the valve is more elongate, A^ ^^.gjgl^l^^ less elevated, and larger (5 mm. in diameter) than the specimens of ^1 ^ff ^^^^mV ^^^ latter from the type locality. iB n^|^^^^^B| The varietal name is given for Mr. F. M. Endlich of the Hayden n ^^^H^HVl Survey. 1 Formation and locality. — Tipper Cambrian: (8o) Limestone 2 miles (3.2 km.) north of Aurum, Schell Creek Range, White Pine Coimty, Nevada. A' Figure 22. — Micromiira sculpiilis endlichi Walcott. A, A', Top and side views of the type speci- men, a ventral valve from Local- ity So, Upper Cambrian lime- stones, 2 miles (3.2 km.) north of AuTum, White Pine County, Nevada (U. S. Nat. Mus. Cat. No. 51498). Micromitra zEnobia n. sp. Text figure 23. Most of the specimens of this species are flattened in the shale, but both valves appear to have been moderately and nearly equally convex. The beak of the ventral valve is slightly in advance of the posterior margin and incurves slightly over a well-defined cardinal slope which is nearly straight and almost as wide as the greatest diam- eter of the shell. The pseudodeltidium is moderately convex and apparently extends about half the distance from the beak to the posterior margin. Growth lines are fairly coarse and regular. In the ventral valve they bend abruptly at the cardinal slope, on which they are verj^ fine and very irregular. In other words, the cardinal slope is well defined and is covered with an irregular confusion of minute ridges which seem to bear little relation to the concentric ridges on the surface of the shell. This pattern can not be seen on the pseudodeltidium. In some of the adult shells from the type locality (35k) a faint radial crenulation can be seen near the apex. Fragments of lime- stone (Locality 57c) contain many small shells, probably the yoimg, with radial folds and a crenulation of the concentric strise similar to that in Micromitra sculptilis. The crenulations have been observed in one perfectly preserved adult specimen. The specimens from the limestone may be distinct. Formation and locality. — Middle Cambrian: (35k) Burgess shale member of the Stephen formation, west slope of ridge between Mount Field and Wapta Peal, 1 mile {1.6 km.) northeast of Burgess Pass, above Field; and (58 1) about 1,830 feet (557.8 m.) above the Lower Cambrian in the limestone forming 3b of the Stephen formation [Walcott, 1908c, p. 238 (7)], on the east side of Mount Stephen about 3,000 feet (914.4 m.) above the Canadian Pacific Railway track 3.5 miles (5.6 km.) east of Field; both in British Columbia. FiGUEE 23.— Micromitra zendbia n. sp. Top ^iew of type specimen, a ventral valve from Locality 35k, Middle Cambrian Stephen forma- tion 1 mile (1.6 km.) northeast of Burgess Pass, above Field, British Columbia (U. S. Nat. Mus. Cat. No. 58311). PATEEINID^. 343 (57c) About 2,500 feet (762 m.) above the Lower Cambrian and 2,475 feet (754 m.) below the Upper Cambrian in the limestone forming 1 of the Stephen formation [Walcott, 1908f, p. 209]; and (58z) about 1,875 feet (572 m.) above the Lower Cambrian and 3,100 feet (945 m.) below the Upper Cambrian in the limestone forming 2b of the Stephen formation [Walcott, 1908f, p. 211]; both on Mount Bosworth, north of the Canadian Pacific Railway between Hector and Stephen, on the Continental Divide between British Columbia and Alberta, Canada. MiCKOMiTKA sp. undt. (Walcott). Plate III, figure 7. Iphidea sp. undet., Walcotf, 1899, Mon. U. S. Geol. Survey, vol. 32, pt. 2, p. 449, PI. LX, fig. 6. (Described and discussed as below as an undetermined species. The specimen represented by fig. 6 is redrawn in this mono- graph, PI. Ill, fig. 7.) Ipkidella sp. undt., Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 305. (Description and discussion copied from preceding reference.) Dorsal valve semicircular, slightly convex. Hinge line somewhat shorter than the width of the shell below; nearly straight, the rostral angle about 180°. Beak small, not elevated. Surface ornamented by extremely fine, radiating, and undulating concentric striae that can be seen in detail only with a strong magnifying glass. Shell substance horny. This form is associated with Micromitra sculptilis (Meek) and, judging from external characters, is closely related to it. The surface ornamentation is of the same character, and, hi the absence of the ventral valve, it is difficidt to distinguish any specific charactsrs on which to base a new species, although the shell is much larger than that of M. sculptilis. Formation and localitt. — ^Middle Cambrian: (302b) Limestones near Crowfoot Ridge, GaUatin quadrangle (U. S. Geol. Survey), Yellowstone National Park, Wyoming. PATEBINA Beecher," subgenus of MICKOMITBA. [Pater, father.] Kutorgina Dall (in part) [not Billings], 1877, BuU. U. S. Nat. Mus. No. 8, pp. 40-41. (Includes reference to speci- mens now referred to Micromitra (Paterina).) Kutorgina Walcott (in part) [not Billings], 1886, Bull. U. S. Geol. Survey No. 30, pp. 101-102. (Genus Kutorgina described, but description also includes reference to specimens now referred to Micromitra, Micromitra {Paterina), and Micromitra (Ipkidella).) Paterina Beecher, 1891, Am. Jour. Sci., 3d ser., vol. 41, p. 345, and footnote. (Gives reasons for proposing Paterina as a new genus.) Paterina Beecher, Hall and Claeke, 1892, Eleventh Ann. Rept. State Geologist New York for 1891, p. 247. (De- scribed.) Iphidea Billings, Hall and Clarke, 1892, idem, p. 249. (Described and accompanied by figures of specimens referred to the subgenus Paterina.) Paterina Beecher, Hall and Clarke, 1892, Forty-fifth Ann. Rept. New York State Museum for 1891, p. 563. (Copy of Hall and Clarke, 1892a, p. 247.) Iphidea Billings, Hall and Clarke, 1892, idem, p. 565. (Copy of Hall and Clarke, 1892a, p. 249.) Kutorgina Hall and Clarke (in part) [not Billings], 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, pp. 90-94. (Copies Walcott's description [1886, pp. 101-102] and discusses genus, but description and discussion also include reference to specimens now referred to Micromitra, Micromitra (Paterina), Micromitra (Iphidella), Protorthis, and Billingsella.) a The synonymy for this suhgenas does not giye a complete record of the various genera under which the species now included in Paterina were formerly placed; it includes only those references in which the subgenus is discussed or described. For the sake of completing the record the remain- ing mere generic references are here listed: Obolus BiUmgs [1861b, p. 6; 1861c, p. 946; 1862e, p. 218; 1863, p. 284). Obolella Holl [1865, p. 102]. Oboldlaf Davidson [1866, p. 62]. Kutorgina Davidson [1868, p. 312; 1871, p. 342). Obolella Phillips [1S71, p. 68). Iphidea Billings [1872b, p. 477; 1874, p. 76]. Obolellusf Roemer [1876, PI. II, flgs. 6a-dJ. Obolella Dall [1877, p. 41). Iphidea Billings [1882, p. 13). Kutorgina Davidson [1883, p. 212). Kutorgina Walcott [1884b, p. 19). Iphidea Walcott [18S6b, p. 100). Iphidea Oehlert [1887, p. 1270]. * Kutorgina Dwight [1889, p. 145]. Kutorgina Walcott [1890, p. 36]. Kutorgina Dwight [1891, p. 105). Iphidea Walcott [1891a, p. 608). Kutorgina Walcott [lS91a, p. 609). Kutorgina Moberg [1892b, p. 112). Platyceras Tate [1892, p. 184). Iphidea Hall and Clarke [lS92o, PI. IV, figs. 6 and 7). Iphidea Grabau [1900, p. 617]. Kutorgina Matley [1902, p. 145). Micromitra Clark and Mathews [I90C, p. 252]. 344 • CA^IBRIAN BRACHIOPODA. Iphidea Billings, Walcott (in part), 1897, Proc. U. S. Nat. Mus., vol. 19, pp. 707-711. (Discussed. The genus as discussed includes species now referred to Micromilm, Micromitra (Paterina), and MicmniLru {Ipkidella) .) Paterina Beecher, Walcott, 1897, idem, p. 708. (Discussed as synonym of Iphidea.) Iphidea Billings, Schucheet (in part), 1897, Bull. U. S. Geol. Sui-vey No. 87, p. 233. (Merely refers Micromitra and Paterina to Iphidea.) IpUdella Walcott (in part), 1905, Proc. U. S. Nat. Mus., vol. 28, p. 304. (Merely proposed to replace Iphidea, but includes refere;ice to specimens belonging with Micromitra, Micromitra (Paterina), and Micromitra (Iphidella).) Iphidea Billings, Grabau and Shimer (in part), 1907, North American Index Fossils, vol. 1, p. 201. (Described, and includes species referred to each of the subgenera Paterina and Iphidella.) Micromitra {Paterina) (Beecher), Walcott, 1908, Smithsonian Misc. Coll., vol. .53, No. 4, PI. XI, and pp. 142 and 143. (Classification of subgenus.) All of the species of Micromitra with plain concentric stride on the outer surface are grouped under Paterina as a subgenus. Beecher [1891, p. 345] quoted " Oholus labradoricus Billings" as the type of liis genus Paterina, supposing that the species represented the simplest form of bracliiopod known. The genus was subsequently shown [Walcott, 1897b, p. 707] to have been previous^ described [Meek, 1873, p. 479] under a diiferent name, Micromitra {Iphidea being preoccupied [Schuchert, 1905, p. 329]), but as it appears necessary to group the shells of which Micromitra {Paterina) lahradorica (Billings) is a typical example under a subgenus, I have adopted Paterina as the name for it. Type. — Eutorgina labradorica swantonensis Walcott [1890, p. 36]. Beecher studied the specimens of the variety Micromitra, {Paterina) labradorica swantonensis (Walcott) wliich were in my laboratory in the United States .National Museum and did not at the time have the specimens of '^Oholus labradoricus" from the St. Lawrence Valley. He mistook the duplicate specimens of the variety for the species, and it was from the material he examined that the area of the ventral valve was subsequently worked out, as shown on Plate II, figures 3d, 3e, and 3f. A list of the species referred to Paterina has been given under the genus Micromitra (p. 336). MiCEOMiTKA (Paterina) bella (Billings). Plate II, figures 1, la-c. ■ ' Iphidea bella Billings, 1872, Canadian Naturalist, 2d ser., vol. 6, No. 4, pp. 477-478, fig. 13. (Described and discussed as a new species; see p. 345, for copy. Fig. 13 is reproduced in this monograph, PI. II, fig. Ic.) Iphidea bella Billings, 1874, Geol. Survey Canada, Paleozoic Fossils, vol. 2, pt. 1, p. 76, fig. 44. (Description and figure copied from preceding reference.)' . : j. , , , > .i , Iphidea bella Billings, 1882, Geol. Survey Newfoundland, Rept. Progress for 1881, Appendix, p. 13, fig. No. 8. (A copy of the preceding reference.) Iphidea bella Billings, Walcott, 1886, Bull. U. S. Geol. Survey No. 30, p. 100, PI. VII, fig. 4. (Copies the original description, Billings, 1872b, pp. 477-478, and discusses species. Pig. 4 is copied from Billings, 1872b, fig. 13, p. 477.) Iphidea bella Billings, Oehlekt, 1887, Manuel de conchyliologie, by Fischer, p. 1270, fig. 1026. (Mentioned in French. Fig. 1026 is copied from Billings, 1872b, fig. 13, p. 477.) Iphidea bella Billings, Walcott, 1891, Tenth Ann. Rept. U. S. Geol. Survey, p. 608, PI. LXVII, fig. 6. (Mentioned. Fig. 6 is copied from Billings, 1872b, fig. 13, p. 477.) Not Iphidea bella Hall and Clarke, 1892, Eleventh Ann. Rept. State Geologist New York, for 1891, p. 249, PI. IV, figs. 4 and 5. (Mentioned. Referred in this monograph to Micromitra {Paterina) labradorica sivantonensis.) Iphidea bella Billings, Hall and Clarke (in part), 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, p. 98, fig. 54, not PL IV, figs. 8 and 9. (Mentioned in the text. Fig. 54 is copied from Billings, 1872b, fig. 13, p. 477. The specimens represented by figs. 8 and 9 are referred in this monograph to Micromitra (Paterina) labradorica swantonensis.) Iphidea bella Billings?, Grabau, 1900, Occas. Papers Boston Soc. Nat. Hist., No. 4, vol. 1, pt. 3, pp. 617-618, PL XXXI, fig. 2. (Described and discussed.) Micromitra bella (Billings), Clark and Mathews, 1906, Maryland Geol. Survey, vol. 6, pt. 1, p. 252, PL XVI, fig. 15. (No text reference. Fig. 15 is copied from Walcott, 1886, PL VII, fig. 4.) Iphidea bella Billings, Grabau and Shimer, 1907, North American Index Fossils, vol. 1, p. 201, fig. 234h, p. 199. (Described. Fig. 234h is copied from Billings, lS72b, fig. 13, p. 477.) The shell described and illustrated by Bilhngs [1872b, jip. 477-478] had a large false area and a convex pseudodeltidium, the width of which at the hinge line was stated to be nearly one-tlrird the whole width of the shell. PATERINID^. 345 I received from Whiteaves what was supposed to be the type specimen of the ventral valve, from Trois Pistoles, but I find that it does not belong to the species described by Billings [1872b, p. 477]. The area is strongly marked, but the pseudodeltidium in the specimen before me is very short, not over one-fifth the height of the deltidial area. In this respect it resembles the pseudodeltidium of 2Iicromitra (Paterina) crenistria (Walcott). It is described in this monograph as M. (P.) logani (Walcott). Under date of July 23, 1896, Professor Whiteaves wrote that there were no other specimens or electrotypes of the types of M. (P.) hella (Billings) in the collections of the Geological Survey of Canada, nor of the closely alHed species of the same genus from Topsail Head, mentioned by Billings [1872b, p. 478]. (See pp. 335 and 350, and PI. II, figs. 1 and Ic.) Billings [1872b, pp. 477-478] describes the genus and species as follows: The ventral ? valve of I. hella is conical, strongly elevated at the beak, hinge line nearly straight, posterior angles narrowly rounded, sides and front nearly uniformly rounded, forming rather more than a semicircle. Posterior side with a large false area and a convex pseudodeltidium, the width of which at the hinge line is nearly one-third the whole width of the shell. The dorsal valve is semicircular, moderately convex^ mostrelevated at the beak. The hinge line appears to be straight. The form and structure of the posterior side (such as the area, foramen, deltidium, etc.) can not be made out from the specimen, owing to its imperfection. The surface is covered with fine concentric strise, which in the ventral? valve are continued around on the area. Of these strise there appear to be from fifteen to twenty in the width of one line, their size varying somewhat in different parts of the specimen. There are also a few obscure radiating striae. Width of ventral valve, seven lines; length, five lines; height, two lines. Very little is to be added to this description from a studj'' of the material from the north side of the Straits of Belleisle and from Pennsylvania, except that the examination of a num- ber of specimens has revealed the fact that there is no true perforation in the beak. Billings states that in the specimen described by Mm there is an aperture in the beak, but in another there is no appearance of one. I observed a narrow furrow near the apex of the beak in a specimen from L'Anse au Loup, Labrador, but there was no aperture through the shell. Several other specimens afford no traces of even a shght slit in front of the beak. The presence of this depression or furrow is mentioned, and its character set forth in the description of the genus Micromitra (p. 335). Formation and locality. — Lower Cambrian: (2ii) Liviestone bowlders in conglomerate, along the shore of the. St. Lawrence, near Trois Pistoles, Temiscouata County; and (2o) limestone bowlders in conglomerate on shore at east entrance to harbor at Bic, Rimouski County; both in Quebec, Canada. (314e [Billings, 1872b, p. 478]) Limestone at Topsail Head, Conception Bay, Newfoundland. (392a) Limestone [Walcott, 1891b, p. 254] at L'Anse au Loup, on the north shore of the Straits of Belleisle, Labrador. (326g [Grabau, 1900, p. 617]) Limestones at East Point, Nahant, Essex County, Massachusetts. (49) Sandstone on Codonis Creek, 0.125 mUe (0.2 km.) below Meyer's mUl, near Emigsville, York County; (346a) limestones in Landis Valley, Lancaster County; and (49w) limestones in raUroad cut 0.25 mile (0.4 km.) south of Emigsville, York County; all in Pennsylvania. (25) Sandstone just above Parker's quam^, near Georgia, Franklin County, Vermont. ]\IiCROMiTRA (Paterina) crenistria (Walcott). Plate III, figures 4, 4a-b. Iphidea crenistria Walcott, 1897, Proc. U. S.Nat. Mus., vol. 19, p. 713, PI. LIX, figs. 4, 4a-b. (Described and discussed essentially as below as a new species. The specimen represented by figs. 4, 4a-b is redrawn in this monogi-aph, PI. Ill, figs. 4, 4a-b.) Ventral valve subconical, beak nearly apical, curving shghtly over to the pseudodeltidium. False area very narrow, separated from the curvature of the shell by being turned somewhat abruptly backward. Pseudodeltidium comparatively broad, but decidedly short as compared with that of Micromitra (Paterina) bella (Billings) or M. (P.) superba (Walcott). It is more the type of that of -J/. (P.) labradorica (BiUings). It is strongly arched, leaving a broad, high space between it and the plane of the shell. Dorsal valve unknown. Surface of ventral valve marked by verj^ fine, shghtly crenulated striae that are so crowded on the false area that they are nearly lost, and only one or two varices of growth and a few striae are shown on the pseudodeltidium. No traces of an apical opening have been seen. On some shells a faint furrow is seen on the apex. 346 CAMBRIAN BRACHIOPODA. This species is clearly distinguished from other described forms of the subgenus by its highly arched pseudodeltidium and crenulated surface strise. An imperfect ventral valve from the upper portion of the Secret Canyon shale of the Eureka district section, Nevada, has somewhat coarser striae than this species, but otherwise it appears to be the same. Specimens from near Schellbourne, Nevada, appear to be identical with the Grand Canyon form. A single imperfect ventral valve, from the Orr formation, 930 feet above the base of the Upper Cambrian, in the House Range section of Utah, is very much like the specimen from the Secret Canyon shale of Nevada and is tentatively placed with it under this species. The Grand Canyon, Utah, and Nevada shells appear to be descendants of M. (P.) lahradorica of the Lower Cambrian and its varieties in the lower portion of the Middle Cambrian of the Cordilleran region. This form owes its specific name to the finely crenulated striae with which its outer surface is characterized. Formation and locality. — Tipper Cambrian: (313) Limestone 0.75 mile (1.2 km.) east-northeast of McGill post office. White Pine Coimty, Nevada. Middle Cambrian: (76) "Tonto" sandstone, near the water's edge, at the mouth of Kanab Canyon, where it enters the Grand Canyon of the Colorado; (73b) sandstone in upper part of Tonto group, lower portion of Kwagunt Valley, Grand Canyon of the Colorado; and (74) sandstone about 300 feet {91.4 m.) above the base of the Tonto group, at the head of Nunkoueap Valley, Grand Canyon of the Colorado; all in Arizona. (313b) Limestone 3 miles (4.8 km.) north-northeast of Schellbourne, Schell Creek Range, White Pine County, Nevada. (13b) Sandstones of the Rome formation, northeast of Rhea Springs [Hayes, 1894, areal geology sheet], Roane County, Tennessee. Specimens somewhat doubtfully referred to this species occur at the following localities: Upper Cambrian: (30j) About 950 feet (289.6 m.) above the Middle Cambrian and 2,450 feet (746.8 m.) below the top of the Upper Cambrian near the base of the arenaceous shales and limestone forming le of the Orr formation [Wal- cott, 1908f, p. 176], on Orr Ridge, about 5 miles (8 km.) south of Marjum Pass, House Range [Walcott, 1908f, PI. XIII], Millard County, Utah. Middle Cambrian: (S8) Shaly limestones in the upper beds of the Secret Canyon shale, east side of New York and Secret canyons, Eureka district [Hague, 1892, Atlas], Eureka County, Nevada. MiCEOMiTRA (Paterina) etheeidgei (Tate). Plate III, figures 10, lOa-c. Platyceras etheridgei Tate, 1892, Trans. Roy. Soc. South Australia for 1892, vol. 15, pt. 2, p. 184, PI. II, figs. 7a-c. (De- scribed and discussed as a new species. The two specimens represented by figs. 7a-c are redrawn in this monograph, PI. Ill, figs. 10, lOa-b.) The original description by Tate follows : Shell srnall, broadly conical; apex obtuse, posterior, recurved, but not spiral, usually protruding beyond the pos- terior margin; aperture roundly oval, but irregular in outline, subtruncated and narrowed posteriorly. Surface orna- mented with rather thick subimbricating concentric folds of growth, and curved beneath the apex coincidently with the posterior margin; faintly radially wrinkled. This very common species exhibits considerable variability in the outline of the aperture, and the amount of back- ward projection of the apex. The shells seem to have lived on ii-regular surfaces, and in some instances at least upon trilobites. The proportionate measures of the basal diameter and height are as 4 to 3 ; the longest diameter observed is 6 mills. The examination of the type specimen of this species shows that the shell substance is corneous, that there is a true false area, and that the species is closely related to Micromitra (Paterina) superha (Walcott). All of the specimens in the collection are ventral valves, and these differ considerably in elevation, apparently owing to the upward arching of the posterior margin beneath the false area. This characteristic distinguishes the species from M. (P.) superha and allied forms. The specific name was given in honor of Dr. R. Etheridge, jr. Formation and locality.— Middle ? Cambrian: (316 [Tate, 1892, p. 184]) Limestone at Curramulka, Yorke Peninsula, South Australia. PATERINID^. 347 MiCROMiTRA (Patekina) labradorica (Billings). Plate II, figures 2, 2a-{. Obolus labradorims Billings, 1861, Geol. Survey Canada, Paleozoic Fossils, vol. 1, p. 6, fig. 6. (Described as a new species. The specimen represented by fig. 6 is redrawn in this monograph, PI. II, fig. 2.) Obolus labradorims Billings, 1861, Report on the Geology of Vermont, vol. 2, p. 946, fig. 345. (Copy of preceding reference.) Obolus labradoricus Billings, 1862, Report on the Economic Geology of Vermont, by Hager, p. 218, fig. 345. (Copy of preceding reference.) Obolus labradoricus Billings, 1863, Geol. Survey Canada, Fifteenth Rept. Progress, p. 284, fig. 291. (No text reference. Fig. 291 is copied from Billings, 1861b, fig. 6, p. 6.) Iphidea labradorica Billings, 1872, Canadian Naturalist, 2d ser., vol. 6, No. 4, p. 478. (Merely changes generic reference.) Iphidea labradorica Billings, 1874, Geol. Survey Canada, Paleozoic Fossils, vol. 2, pt. 1, p. 76. (Copy of preceding reference.) Kutorgina labradorica (Billings), Walcott (in part), 1886, Bull. U. S. Geol. Survey No. 30, p. 104, not PI. IX, figs. 2 2a-b. (Original description, Billings, 1861b, p. 6, copied and species discussed. The specimens figured, however, belong with Micromitra (Paterina) labradorica swantonensis .) Not Paterina labradorica Beecher, 1891, Am. Jour. Sci., 3d ser., vol. 41, footnote, pp. 345-346, PI. XVII, figs. 1 and 2. (The specimens here referred to belong with Micromitra (Paterina) labradorica swantonensis.) Kutorgina labradorica (Billings), Walcott, 1891, Tenth Ann. Rept. U. S. Geol. Survey, p. 609, PI. LXIX, figs. 3, 3a-b. (Mentions new locality. The specimens represented by figs. 3, 3a-b are redrawn in this monograph, PL II, figs. 2d, 2c, and 2a, respectively.) Not Paterina labradorica Hall and Clarke, 1892, Eleventh Ann. Rept. State Geologist New York, for 1891, p. 247, fig. 258. (Genus Paterina described. Fig. 258 is copied from Walcott, 1886b, PI. IX, figs. 2b and 2a, but the specimens belong with Micromitra (Paterina) labradorica swantonensis.) Iphidea labradorica (BUlings), Schuchert (in part), 1897, Bull. U. S. Geol. Survey No. 87, p. 234. (Accepts Billings's reference of "Obolus labradoricus" to Iphidea, but includes reference to specimens of Micromitra (Paterina) labradorica swantonensis.) Iphidella labradorica Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 307. (Merely changes generic reference.) Ventral valve depressed, conical; the beak high and arched over the narrow area. Car- dinal slopes flattened so as to form a narrow false area, which is clearly defined from the curvature of the shell by a sharp angle ; pseudodeltidium unknown. Dorsal valve moderately convex, transverse, the hinge line being usually a little shorter than the greatest width of the shell below. Beak small, slightly incurving over the pseudo- deltidium. In some specimens there is a broad low mesial sinus, while in others this feature is scarcely discernible. Cardinal slope nearly vertical, forming a clearly defined narrow area, broken at the center by a broad pseudodeltidium, the center of which is marked by a rather broad, slight groove. The pseudodeltidium is well shown in two specimens, but the details of its characters are not so well exhibited as in specimens of the dorsal valve of Micromitra {Iphidella) -pannula (White). Stride of growth cross the false area and pseudodeltidium. The surface is marked by rather fine concentric striae that are quite regular near the apex of the shell, but less so outward toward the margin, as sho%vn by the type specimens that Whiteaves kindly sent on to me for study. These also show fine, radiating strise that cross the concentric strise and lines of growth, giving to the strise a slightly crenulated appearance somewhat similar to that of Micromitra {Paterina) prospectensis (Walcott). Where the shell is exfoliated, radiating striae are distinctly shown on the cast of the interior. On specimens from the limestone carrjdng Olenellus, etc., at Topsail Head, Conception Bay, Newfoundland, the sm-face striae are less distinctly marked and the shells are smaller, but there appears to be no specific difference between those from the Straits of Belleisle. Shell substance corneous. With a type specimen from L'Anse au Loup before me for comparison with the form from the Lower Cambrian limestone east of Swanton, Vermont, I am still inclined to distinguish the latter as the variety swantonensis. The strise of the Swanton shells are usually finer and more regular and the valves less transverse in proportion to the length. It is quite probable that these differences would largely disappear on the comparison of a larger series of specimens from the type locality, as there is a considerable range of variation among those from east of Swanton and those from Topsail Head. 348 CAMBEIAN BRACHIOPODA. In the Hanford Brook section of New Brunswick I found very good illustrations of this species in ^Matthew's "Etclieminian." This form owes its specific name to its occurrence at the Straits of Belleisle, Labrador. Formation and locality. — Lower Cambrian: (41a) Limestone [Walcott, 1891b, p. 260] on the mainland beneath Topsail Head, Conception Bay; (314e [^^'alcott, 1886a, p. loO]) limestone at Topsail Head, Conception Bay; (5r) lime- stone near the railroad track 1.5 miles (2.4 km.) west of the railway station at Manuels, Conception Bay; (St) shale and limestone nodules about 20 feet (6 m.) above the base of the Cambrian, on Redrock Point, near Chappie Cove, Holh-wood Point, Conception Bay; (51) limestone on Smith Point, in Smith Sound, Trinity Bay; and (314f) lime- stone of B7 of the section at Bonne Bay [Walcott, 1891b, p. 255]; all in Newfoundland. (392a) Limestones [Walcott, lS91b, p. 2S4] at L'Anse au Loup on the north shore of the Straits of Belleisle, Labrador. (3a) 450 feet (137.1 m.) below the quartzite in the St. John formation and over 500 feet (152.4 m.) below the Protolenus zone of Matthew [Walcott, 1900, pp. 320-322], Hanford Brook; and (301v [Walcott, 1900, p. 322]) sandy shales of Division 2b of the "basal series' ' of ^Matthew, on Hanford Brook; both in St. John County, New Brunswick. (2o) Limestone bowlders in conglomerate on shore at east entrance to harbor at Bic, Eimouski County, Quebec. (2b) Limestone just north of Beman Park, in the northeastern part of the city of Troy, Troy quadrangle (U. S. Geol. Survey), Rensselaer County, New York. (304o) Sandstone at Nuneaton, England. (Iv) Shales of No. 3 of the Silver Peak group, Barrel Spring section [Walcott, ]908f, p. 189], 3 miles (4.8 km.) north of Valcalda Spring and 4 miles (6.4 km.) west-northwest. of the Drinkwater mine. Silver Peak quadrangle (U. S. Geol. Survey), Esmeralda County, Nevada. (57r and 58s) About 150 feet (46 m.) below the Middle Cambrian near the base of the limestones forming 3 of the Mount A^Tiyte formation [Walcott, 1908c, p. 241 (10)], just above the tunnel on the north shoulder of Mount ; Stephen, about 3 miles (4.8 km.) east of Field, British Columbia. Specimens somewhat doubtfidly referred to tliis species occur at the following locality: Lower Cambrian: (2r) Limestone bowlders in a conglomerate in a cut on the Intercolonial Railway, 2 miles (3.2 km.) west of Bic railway station, Rimouski County, Quebec. MiCROMiTRA (Paterina) labradorica orientalis (Walcott). Plate II, figure 11. Iphidella labradorica orientalis Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 305-306. (Characteiized as below as a new variety.) Only one dorsal valve of this shell occurs in the collection. Its general form and surface characters are very much like those of Micromitra (Paterina) labradorica swantonensis (Walcott) [PI. II, figs. 3, 3a-f]. Tlie varietal name is given more on account of the fact that this shell occurs in China and the variety swantonensis on the eastern side of the North American con- tinent than from any marked differences between the shells from the two localities. It may be that with. a good series of shells from China differences would be found that are not to be determined with only the single shell for comparison. Formation and locality. — Middle Cambrian: (C9) Lower limestone member of the Kiulung gi-oup [Blackwelder, 1907a, pp. 37 and 39 (3d list of fossils)], 3 miles (4.8 km.) southwest of Yenchuang, Sintai district, Shantung, China. Micromitra (Paterina) labradorica swantonensis (Walcott). Plate II, figm-es 3, 3a-f. Kutorgina labradorica Walcott (in part) [not (Billings)], 1886, Bull. U. S. Geol. Survey No. 30, PI. IX, figs. 2, 2a-b. (The text reference [on page 104] includes only specimens belonging to the species Micromitra (Paterina) labra- dorica. The figures represent specimens of the variety swantonensis, which are redrawn in this monograph, PI. II, figs. 3, 3a-b, respectively.) Kutorgina labradorica swantonensis Walcott, 1890, Proc. U. S. Nat. Mus. for 1889, vol. 12, p. 36. (Characterized as a new variety.) Paterina labradorica Beecher [not (Billings)], 1891, Am. Jour. Sci., 3d ser., vol. 41, footnote, pp. 345-.346, PI. XVII, figs. 1 and 2. (Discussed as the type of the new genus Paterina. Figs. 1 and 2 are copied from Walcott'a figures, 1886b, PL IX, figs. 2b and 2, respectively.) Kutorgina labradorica siDantonensis Walcott, 1891, Tenth Ann. Rept. U. S. Geol. SiU'vey, p. 609, PI. LXIX, figs. 2, 2a-b. (Characterized. Figs. 2, 2a-b are copied from Walcott, 1886b, PI. IX, figs. 2, 2a-b.) Paterina labradorica Hall and Clarke [not (Billings)], 1892, Eleventh Ann. Rept. State Geologist New York for 1891, p. 247, fig. 258. (Genus Paterina described. Fig. 258 is copied from Walcott, 1886b, PI. IX, figs. 2b and 2a.j Iphidea bella Hall and Clarke [not Billings], 1892, idem, p. 249, PI. IV, figs. 4 and 5. (Mentioned.) PATEKINID^. 349 Iphidea bclla Hall and Clarke (in part) [not Billings], 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, p. 98, PI. IV, figs. 8 and 9 (not fig. 54, p. 98, which is refen-ed in this monograph to Micromitra (Patenna) bclla). (Men- tioned in the text. Figs. 8 and 9 are copied from Hall and Clarke, 1892a, PL IV, figs. 4 and 5, respectively.) Iphidea labradorica Schuchert (in part) [not (Billings)], 1897, Bull. U. S. Geol. Sm-vey No. 87, p. 234. (Accepts Billings's reference of "Obolus labradoncus" to Iphidea, but includes reference tQ_ specimens of both Micromitra (Paterina) labradorica 3,nd its -vsiricty swantonensis .) Iphidea labradorica swantonensis (Walcott), Schuchert, 1897, idem, p. 234. (Merely changes generic reference.) Iphidella labradorica swantonensis Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 307. (Merely changes generic reference.) Iphidea swantonensis (Walcott), Geabau and Shlmer, 1907, North American Index Fossils, vol. 1, p. 201, figs. 234i and 234], p. 199. (Described. Figs. 234i and 234] are copied.from Walcott, 1886b, PI. IX, figs. 2a and 2b, respectively.) The general form of the two valves of this variety is so close to that of Micromitra (Paterina) labradorica (BiUings) (p. 347) that it will not be necessary to repeat the description. The dif- ferences existing in the variety svjantonensis have been mentioned in describing the species. The variety is exceedingly abundant in the Olenellus-he ariiig limestone, 2 miles (3.2 Ivm.) east of Swanton, Vermont, in association with Eutorgina cingulata (Billings). Shell substance corneous. The most interesting addition to our taiowledge of the species is the discovery of the presence of a narrow area on the ventral valve and a short pseudodeltidium, as shown in a longitudinal section (PL II, figs. 3c-f). The existence of the area and pseudodeltidium in the ventral valve of the variety swantonensis, the form studied by Beecher, and in the dorsal valve of M. (P.) labradorica, was unknown at the time that Beecher [1S91, p. 345] selected M. (P.) labradorica swantonensis (see p. 344) as the simplest form or prototj-pe (Paterina), "preserving throughout its development the main features of a protegulum, and showing no separate or distmct stages of growth." The discovery of the area and iDseudodeltidium refers the species and its varieties to the genus Micromitra [Walcott, 1897b, p. 707]. The exact stratigraphic position of Locahty 87 has not been made out, but from the associated species of Agnostus and Pt^jchoparia, it is evidently to be referred to the Middle Cambrian. This form owes its varietal name to its occurrence in tlie vicinity of Swanton, Vermont. Formation and locality. — Middle Cambrian: (87) Conglomeratic limestone 1 mile (1.6 km.) south-southwest of Highgate Falls, Franklin County, Vermont. Lower Cambrian: (25a) Limestone on the Hall (Donaldson's) farm, 2 miles (3.2 km.) east of Swanton; (319z) sandy limestone 2.5 mUes (4 km.) east of Swanton; (26) sandstone northeast of the Corman farm buildings, east of Highgate Springs; and (319y) sandstone 2 miles (3.2 km.) east-southeast of Highgate Springs; all in Franklin County, Vermont. (319x) Limestone at the crossing of East Creek and Grove Street, 1.25 miles (2 km.) north of Rutland, Rutland County, Vermont. IVIicROMiTRA (Paterina) labradorica utahensis (Walcott). Text figure 24, page 350; Plate II, figures 8, 8a. Iphidella labradorica utahensis Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 306. (Characterized as a new variety.) The general form of this variety is much like that of Micromitra (Paterina) labradorica (Bilhngs). It differs from it in the fine, threadlike, concentric stria? of the outer surface, in this respect approaclung M. alabamaensis (Walcott) and M. (P.) superba (Walcott). During the field season of 1906 fine specimens of tliis variety were found in the limestones 760 and 1,200 feet above the quartzitic sandstones referred to the Lower Cambrian. A ventral valve 6 mm. in width has a convex pseudodeltidium 1.25 mm. in length, with a width of 2.5 mm. at its shghtly arched margins. The variety swantonensis also has a wide, convex pseudodeltidium (PI. II, figs. 3e, 3f). Formation and locality.— Middle Cambrian: (30c) About 1,050 feet (320 m.) above the Lower Cambrian and 3,350 feet (1,021.1 m.) below the Upper Cambrian in the shales forming Id of the Swasey formation [Walcott, 1908f, p. 182], at the head of Dome Canyon, House Range [Walcott, 1908f, PI. XIII], Millard County; (3d) concretionary lime- stone about 100 feet (30.5 m.) above the quartzitic sandstones of the Cambrian, at Ophh, OquiiTh Range, Tooele County; (30p) about 125 feet (38 m.) above the Cambrian quartzitic sandstones, on the north side of Ogden Canyon, 350 CAMBRIAN BRACHIOPODA. Figure 24.— ilicromilra {Paterina) labraiorica utahemis (Wal- cott). A, A', A", Top, side, and back views of a ventral valve from Locality 54m, Middle Cambrian limestones in Blacksmith Fork Canyon, Cache County, Utah (U. S. Nat. Mus. Cat. No. 51434). about 1 mile (1.6 km.) above its mouth, east of Ogden, Weber County; (30u) about 250 feet (76.2 m.) above the top of the Cambrian quartzitic sandstones, in sandy shales, 4 miles (6.4 km.) northwest of Promontory Point (on the " Lucia cut-off " of the Union Pacific Railway), about halfway up west end of ridge, north of Great Salt Lake, Boxelder County; (34m) limestone about 765 feet (233.2 m.) above the Brigham quartzite [Walcott, 1908a, p. 8], 1 mile (1.6 km.) northwest of Geneva (Copenhagen), east of Brigham, Boxelder County; and (32d) shales about 150 feet (45.7 m.) above the Brigham quartz- ite fW'alcott, 1908a, p. 8], on the east side of the south fork of Paradise Dry Canyon (locally known as East Fork), east of Par- adise, Cache Valley, Cache County; all in Utah. (54a) About 750 feet (228.6 m.) above the Brigham quartzite and 3,440 feet (1,048.5 m.) below the Upper Cambrian ia the shales forming 2a of the Ute limestone fW'alcott, 1908f, p. 196]; (54:0) about 900 feet (274.3 km.) above the Brigham quartzite and 3,300 feet (1,005.8 m.) below the Upper Cambrian in the limestone beds forming lb of the Ute limestone fW'alcott, 1908f, p. 196]; and (54m) about 1,225 feet {.373.4 m.) above the Brigham quartzite and 2,950 feet {899.2 m.) below the Upper Cam- brian in the upper part of the limestone forming la of the Ute limestone- [Walcott, 1908f, p. 19S\; all in Blacksmith Fork Canyon, about 10 miles (16.1 km.) east of Hyrum, Cache County, Utah. MicROMiTRA (Paterina) labradorica var. undt. This form is distinguished from Micromitra (Paterina) labradorica (Billings) and its varie- ties by having much finer and more closely arranged concentric striae. In other characters it approaches very closely to the tj^pical forms of the species. Formation and locality. — Lower Cambrian : (Iv) Shales of No. 3 of the Silver Peak group, Barrel Spring section [Walcott, 1908f, p. 189], 3 mOes (4.8 km.) north of Valcalda Spring and 4 miles (6.4 km.) west-northwest of the Drink- water mine, Silver Peak quadrangle (U. S. Geol. Survey), Esmeralda County, Nevada. Micromitra (Paterina) logani (Walcott). Plate II, figures 6, 6a-b. Iphidea logani Walcott, 1897, Proc. U. S. Nat. Mus., vol. 19, pp. 711-712, PI. LIX, figs. 2, 2a-b. (Described and discussed essentially as below as a new species. The specimen represented by figs. 2, 2a-b is redrawn in this monograph, PI. II, figs. 6, 6a-b.) Ventral valve conical, transverse in outline at the base, almost semicircular. Beak minute, incurving over the pseudodeltidium. Cardinal slopes rounded and flattened so as to form a fairly well-defined false area that is broken by a very wide triangular space. Pseudodeltidium arching upward, forming a narrow, sloping shelf beneath the beak, the angle of slojje from the summit of the shell over the beak and pseudodeltidium being nearly the same as the slope from the summit to the front. Surface marked by very fine concentric strise and somewhat coarser hnes of growth. Under a high power shght traces of radiating strise may be observed. The concentric strise pass around over the false area and cross the pseudodeltidium. Shell substance corneous. Ohservations. — This specimen was received from Whiteaves, of the Geological Survey of Canada, as the type of M. (P.) bella (BLUings). It differed, however, so materially from the description of that species [Billings, 1872b, pp. 477-478] and the figure iUustrating it that I found it necessary to give it a distinct specific designation. (See pp. 335 and 345.) This species approaches most nearly M. (P.) crenistria (Walcott) in its short pseudodel- tidium and finely striated surface. It differs, however, in the character of the surface striae, the form of the false area, and the pseudodeltidium. The specimen bears the label "Trois Pistoles, 1868, T. C. Weston." It was collected from a bowlder in the conglomerate at that locality, and it is probably of Middle Cambrian age, though this can not be stated positively, as there are -no associated fossils. Bilhngs [1872b, p. 478] speaks of the occurrence of fragments of trilobites in the bowlder containing his type of Micro- mitra {Paterina) hella. He does not mention the genera or species. PATERINIDiE. 351 The conglomerates of this formation, according to Logan, form 9 separate layers, from 2 to 16 feet thick, bedded in gray calcareous sandstone. The geologic age of the deposit of the matrix is supposed to be Upper Cambrian or Lower Ordovician. The age of the bowlders can only be determined by the fossils found in each. The specific name was given in honor of Sir WiUiam E. Logan. Formation and locality. — Middle? Cambrian: (2n) Limestone in conglomerate on shore near Trois Pistoles on St. Lawrence River, Province of Quebec, Canada. MiCROMITRA (PaTEEINA) MAJOR (Walcott) . Text figure 25. Iphidella major Walcott (in part), 1905, Proc. U. S. Nat. Mus., vol. 28, p. 304. (Described and discussed some-whatas below as a new species. Specimens now referred to Micromitra (Paterina) uillwrdi were included with the specimens representing Micromitra (Paterina) major when this description was given.) Oboltis smithi Walcott (in paxt), 1908, Smithsonian Misc. Coll., vol. 53, No. 3, PI. VII, fig. 9 (not fig. 9a, which rep- resents a specimen of Obolus smithi). (No text reference. Fig. 9, which is reproduced in this monograph as fig. 25, was inserted on PL VII of the above reference by mistake. All of the figures representing the two species {Obolus smithi and Micromitra (Paterina) major) happened to be grouped on the same preliminary plate, and when two figures were chosen to represent Obolus smithi in the paper referred to, one of the figures representing Micromitra (Paterina) major was accidentally included.) Ventral valve subcorneal, with the apex sHghtly in front of the posterior margin. A minute beak appears to incurve over the pseudodeltidium. Cardinal slope rather abruptly rounded, so as to indicate a rather narrow false area. Pseudodeltidium broad and convex, with its lower margin arched so as to leave a space between it and the plane of the margin of the shell. Dorsal valve shghth" convex, with a narrow area. Surface, so far as can be determined from the badly preserved mate- rial, marked b.y rather strong growth hnes and very fine concentric striae. (Paterina) major (Wai- The largest dorsal valve has a length of 10.5 mm."; vndth, 13 mm. Only va"^e from Locamy mc' one small ventral valve is known. Lower Cambrian beds in Ohservations. — The material representing this species is more or less tevX)sh™e^')Ti25mUM compressed and distorted in the argillaceous shales in which it occurs. ^'-^ ^^■'> northeast of In general form it is not unhke that of Micromitra (Paterina) lahradorica Aiabanla (u.'^ s.^^Na^' (Bilhngs) (PI. II, figs. 2, 2a-f), but it differs m its nearly smooth surface mus. cat. No. 51499). and the position of the apex. It is, however, the southern Appalachian [Waicott,i9osd,pi.vii,fig. representative of that species. The original description of this species was ^^^^^^IJ^omTs^smMr^l based on specimens now referred to this species and to Micromitra {Pater- was given cat. no. sieiia. ina) williardi Walcott. Very good specimens of the latter are now avaU- unXttTsfeolTd reference able from two locahties near Helena, Alabama. 1° tte synonymy, this was This form owes its specific name to its large size. Formation and locality. — lower Cambrian: (56c) Rome {" Montevallo") formation along roadjuM north of Buck Creek, 1.125 miles(l.S km.) northeast of Helena; and (17b) Rome ("Montevallo") formation 4 miles (6.4 km.) south of Helena; both in Shelby County, Alabama. A dorsal valve similar to the one illustrated above occurs at the following locahty: middle Cambrian: (90) Conasauga ("Coosa") shale on Edward's farm, near Craigs Mountain, about 10 miles (16.1 km.) southeast of Center, Cherokee County, Alabama. Micromitra (Paterina) phillipsi (Holl). Plate III, figure 8. Obolella phillipsi Holl, 1865, Quart. Jour. Geol. Soc. London, vol. 21, pt. 1, p. 102, figs. lOa-c. (Described as a new species. The specimen represented by figs. 10b and 10c is redrawn by Davidson, 1866, PL IV, figs. 17a and 17c, and Davidson's figures are copied in this monograph, PL III, fig. 8.) Obolella ? phillipsi Holl, Davidson, 1866, British Fossil Brachiopoda, vol. 3, pt. 7, No. 1, pp. 62-63, PL IV, figs. 17-19. (Described and discussed. Figs. 17a and 17c are drawn from the specimen represented in figs. 10b and 10c of the preceding reference, and are reproduced in this monograph, PL III, fig. 8.) Kutorgina cingulata Davidson [not (Billings)], 1868, Geol. Mag., vol. 5, p. 312, PL XVI, fig. 10. (Discussed.) 352 . CMIBRIAN BRACHIOPODA. Kutorgina cingulata Davidson [not (Billings)], 1871, British Fossil Brachiopoda, vol. 3, pt. 7, No. 4, pp. 342-343, PL L, fig. 25. (Discussed. Fig. 25 is copied from fig. 10 of preceding reference (p. 351) and erroneously referred to in the description of PI. L as " Kortugina cingulata.") OboleUa phiUipsi Hall, Phillips, 1871, Geology of Oxford and the Valley of the Thames, p. 68, Diagram XVII, fig. 12. (No text reference.) Obolelltis ? phiUipsi (Holl), Koemer, 1876, Lethtea geognostica, pt. 1, Letheea palseozoica, atlas, PI. II, figs. 6a-d. (No text reference. Figs. 6a-d are copied from Davidson, 1866, PI. IV, iigs. 19, 17a, 17c, and 17b, respectively.) OboleUa phillipsia Holl, Dall, 1877, Bull. U. S. Nat. Mus. No. 8, p. 41. (Mentioned as possibly belonging to an undescribed genus.) Kutorgina cingulata Davidson [not (Billin&s)], 1883, British Fossil Brachiopoda, vol. 5, pt. 2, p. 212. (Characterized.) Kutorgina cingulata Walcott (in part) [not (Billings)], 1886, Bull. U. S. Geol. Survey No. 30, pp. 102-104. (Speci- mens now referred to Micromitra (Paterina) phiUipsi were included with the specimens representing Kutorgina cingulata when this description was written.) Kutorgina cingulata phiUipsi (Holl), Matley, 1902, Quart. Jour. Geol. Soc. London, vol. 58, pt. 1, pp. 145-147. (Described and discussed as a variety.) Tlie orio;inal description by Holl follows : Semicircular, slightly broader than long; hinge-line straight, nearly equal to the greatest width of the shell. Ventral valve prominent at the beak, depressed near the margin; beak small, round, pointed, and situated close to the posterior margin. Dorsal valve evenly convex, slightly depressed at the angles; umbo obtuse. A slight mesial depres- sion toward the anterior border in both valves. Surface marked with numerous moderately fine, sharply defined, rather unequal, concentric strise, at about their own width apart. Length of a large specimen one-fourth inch, width one-third inch. The shell structure, where the outer layer has become exfoliated, is strongly punctate. Observations. — Davidson [1S6S, j). 312] refers this form to Kutorgina cingulata (Billings) under the belief that the American and English species occur at the same relative geologic horizon. The American siDCcies, however, occurs in association wdth the Olenellus fauna. With the identification of the types of Kutorgina cingulata (Billings) and Kutorgina labradorica (Billings), the latter species being referred to Micromitra (Paterina), it is no longer possible to refer HoU's species to Kutorgina cingulata, it being clearly congeneric with Micromitra {Paterina) labradorica. It differs specifically from that species in a more depressed ventral valve. The specific name was given in honor of Mr. J. Phillips. Formation and locality. — Upper Cambrian: (304g [Holl, 1865, p. 89}) Sandstones of the Hollybush series, Mal- vern Hills, between Herefordshire and Worcestershire, England. Lower Cambrian: (304c) "Malvern quartzite " at Raggedstone Hill; and (304d) "Malvern quartzite " at Mid- summer Hill; both [Groom, 1902, p. 94] in the Malvern Hills, between Herefordshire and Worcestershire, England. Micromitra (Paterina) prospectensis (Walcott). Plate II, figures 4, 4a. Kutorgina prospectensis Walcott, 1884, Mon. U. S. Geol. Survey, vol. 8, p. 19, PI, IX, figs. 1, la-b. (Described as a new species. The specimens represented by figs. 1, la-b are redra^vn in this monograph, PL II, figs. 4a and 4, respectively.) Kutorgina prospectensis Walcott, 1886, Bull. U. S. Geol. Survey No. 30, pp. 106-107, PL IX, figs. 3 and 3a. "(Copies original description and discusses species. Figs. 3 and 3a are drawn from the specimens figured by Walcott, 1884b, PL IX, figs, la and 1, respectively.) Kutorgina prospectensis Walcott, 1891, Tenth Ann. Kept. U. S. Geol. Survey, p. 610, PL LXIX, figs. 4 and 4a. (Men- tioned. Figs. 4 and 4a are copied from Walcott, 1886, PL IX, figs. 3 and 3a, respectively.) Iphidea prospectensis (Walcott), Schuchert, 1897, Bull. U. S. Geol. Survey No. 87, p. 234. (Merely changes generic reference.) Iphidella prospectensis Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 307. (Merely changes generic reference.) Ventral valve subcorneal, moderately elevated. Dorsal valve moderately convex, the beak curving down to the posterior margin. The character of the area and pseudodeltidium is unkno\vn. The surface slopes gently from the front to the highest point of the valve and arches down to the point of the beak. There is no trace of a mesial sinus. The cardinal slopes diverge from the beak at an angle of about 170°. Shell substance corneous. PATERINID^. 353 The surface of both valves is marked by clearly defined, regular, concentric striae that are shghtly crenulated by striae radiating from the beak outward to the margia. The concentric strife show 10 in a distance of 1 mm. and S at the center of the dorsal valve. Observations. — Notliing is knowTi of the interior or the areas of either valve. The clearly defined concentric strise, the thick corneous sheU, and the long convex pseudodeltidium dis- tinguish the species from all others of the genus known to me, with the possible exception of Micromitra {Paterina) labradorica swantonensis (Walcott). In the latter species, however, the striae are less regular, and present quite a different appearance under the magnifier. In the original description [Walcott, lSS4b, p. 19] the comparison was made with Kutorgina cingulata (Billings) as to certain points of resemblance between M. (P.) prospedensis and the young shells of K. cingulata. Tliis form owes its specific name to its occurrence on Prospect IMountain in the Eureka district, Nevada. Formation and locality. — Lower Cambrian: (Im and Ip) Limestones of No. 2 of the Silver Peak group, Barrel Spring section [Walcott, 1908f, p. 189], about 2.5 miles (4 km.) .south of Barrel Spring and 0.5 mile (0.8 km.) east of the road, in the extreme southeastern comer of the Silver Peak quadrangle (U. S. Geol. Survey), Esmeralda County; and (52) arenaceous shales just above the Prospect Mountain quartzite, in a stratigraphic position similar to that of the Pioche shale [Walcott, 1908/ , p. 184], at the top of Prospect Mountain, Eureka district [Hague, 1893, Atlas], Eureka County; both in Nevada. Micromitra (Paterina) stissingensis (Dwight). Plate III, figures 1, la-e. Kutorgina stissingensis Dwight, 1889, Am. Jour. Sci., 3d ser., vol. 38, pp. 145-147, PL VI, figs. 5-8. (Described and discussed as a new species; see below for copy of paragraph on p. 146. The specimens represented by figs. 5, 6, and 8 are redrawn in this monograph, PL III, figs. Ic, 1, and la, respectively.) Kutorgina stissingensis Dwight, 1891, Trans. Vassar Brothers' Inst, for 1887-1890, vol. 5, pt. 2, p. 105, figs. 5-8, p. 108. (Described and discussed as a new species.) Iphidea stissingensis (Dwight), Schuchert, 1897, Bull. U. S. Geol. Survey No. 87, p. 234. (Merely changes generic reference.) Iphidella stissingensis (Dwight), Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 308. (Merely changes generic reference.) All the specimens of this species known to me are more or less compressed in an argillaceo- arenaceous shale and impure limestone. As far as can be determined the ventral valve is obtusely conical, with the apex shghtly incurving. Dwight [1889, p. 145] in his original description mentions the presence of a distinct false area on the ventral valve, and I find in the two specimens traces of the area, also a wide, low, shghtly convex pseudodeltidium. The dorsal valve appears to have been slightly convex and to have resembled closely the general form and proportions of the same valve of Micromitra (Paterina) labradorica (BiUings). One somewhat crushed specimen shows a very low false area and a rather broad, low pseudo- deltidium somewhat like that of M. (P.) labradorica. It is too imperfect, however, for detailed description or illustration. The surface of both valves is covered with very fine, sharp, shghtly crenulated stria and fine ridges of growth, crossed by very fine radiating striae and fine radiating undulations of the same type as those in Micromitra sculptilis (Meek). The concentric striae cross the false areas and pass over the pseudodeltidium. Shell substance corneous. Dwight [1889, p. 146] describes the surface markings in detail as follows: The concentric ridges are somewhat wavy as seen under a strong magnifier; they are semicircular; a number of those lying nearest to the front margin run out along the upper part of the lateral margins, but the remainder and larger number terminate in regular order along the cardinal border. In front of the central portions of the shell the concentric ridges, which number about 12 to 15 to a millimeter, are regularly concentric; but nearer to the beak the number and the irregularity greatly increase. At a point about one-third the length of the shell from the beak there are 25 or more to the millimeter; as the radiating plications are numerous in this part, there is caused a complexity of curves, which under a powerful magnifier produces the effect of elegant and delicate basketwork. The radiating undulations are very irregular in position and number; they are not thoroughly continuous from the beak in specimens 62667°— VOL 51, pt 1—12 23 354 aOIBRIAN BRACIIIOPODA. observed, but appear at irregular intervals singly or in groups; while apt to be croT^ded around the beak, they are rare near the front mar^. On the best specimens about 25 have been counted in the central part of the shell just forward of the beak; had they extended ia equal distribution around it, quite to the cardinal border, there would have been about 50. They are also unequal in breadth; where they are somewhat regular, the interspaces about equal the plications in width; these plications are multiplied by implantation. Observations. — Some young specimens show a surface ornamentation verj^ much like that of Micromitra sculpfUis Oleek) (PI. Ill), but the ornamentation of the adult shell is quite distinct. As stated by Dwight [1SS9, p. 147], fragments of the shell in the shale might be taken for the shell of "Lingulepis pmniformis" (see LinguleUa (Lingulepis) acuminata (Con- rad), p. 545). He also caUs attention to the general resemblance to Micromitra (Paterina) lairadorica (Billings). Attention has been called under the description of 21. alabamaensis (Walcott) (p. 337) to the similarity of form and surface ornamentation between that species, M. (P.) Idbradorica (Billings), J/. (P.) l-ahradonca simntonensis (Walcott), and M. (P.) stisdngensis. An apparently identical form occurs at Mount Stephen, British Columbia, in association with Ogygopsis Tdotzi (Rominger). It has the same outline and shows the variations of surface ornamentation so characteristic of J/. (P.) stisdngensis (Dwight) from Xew York. The radial markings are lightly impressed and are so often entirely obscured that the Mount Stephen form frequenth' resembles the form described under the name of Micromitra zenohia (p. 342). This form owes its specific name to its occurrence near Stissing, New York. Formation and locaxity. — Middle Cambrian: (367d [Dwight, 1889, p. 145]) Limestone near Stissing, Dutchess Count}.-, New York. A single specimen of a dorsal valve 3 mm. in width, that is apparently identical with shells of similar size from the type locahty, occurs at the foUowing locahty: Middle Cambrian: (11m) Drill cores of Umestone in the Boimeterre limestone at horizons 10 and 20 feet (3 and 6 m.) above the Lamotte sandstone, St. Francois County, Missouri. Apparently identical forms occur at the foUowing locahty: Middle Cambrian: (14s) About 2,300 feet (701 m.) above the Lower Cambrian and 2,700 feet (823 m.) below the Upper Cambrian, in the Ogygopsis zone of the Stephen formation [Walcott, 1908f, p. 210], at the "fossil bed" on the northwest slope of Moimt Stephen, above Field, on the Canadian Pacific Railway, British Columbia. ilicEOMiTEA (Pateexna) stissingensis ora u. var. This form is distinguished from the specimens tentatively referred to Micromitra (Paterina) stissingends on Mount Stephen and from the typical specimens of the latter species in New York by its uniformly larger size and in its distinct radial striation. The Mount Stephen representatives of M. (P.) stisdngends frequently betray so little evidence of radial striation that they resemble Micromitra zenoHa, a form which is associated with M. (P.) stissingends ora and which differs from the latter variety in the entire absence of radial striation. It is possible that the Canadian forms will prove to be distinct from the New York species. Nothing is known of the cardinal area or pseudodeltidium of M. (P.) stissingends ora. Formation and locality. — Middle Cambrian: (35k) Shales in the Stephen formation on the west slope of the ridge between Mount Field and Wapta Peak, 1 mile (1.6 km.) northeast of Burgess Pass, above Field, British Columbia. MiCEOMiTEA (Pateeixa) stuarti Walcott. Text figures 26A-B, page 355. Micromitra (Paterina) stuarti Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, p. 58, PL YII, figs. 8 and 8a. (Described and discussed as below as a new species. Figs. 8 and 8a are copied on page 355, figs. 26A and 26A", respectively.) Ventral valve subcortical, with a minute beak arching slightly over a short pseudodeltidium. Cardinal slope with a rounded angle that extends from the beak to the posterolateral margin and defines a very narrow, flattened area on each side of a high triangular fissure that is covered for a short distance at the top by a very short, arched pseudodeltidium. PATERINIDiE. 355 FiGUEE 26. — MiCTomitra (,Patcnna) sluarti Walcott. A, A', A", Top, side, and back views of ventral valve, the type specimen (U. S. Nat. Mus. Cat. No. 514S5a). B, B', Top and side of dorsal valve (U. S. Nat. Mus. Cat. No. 514S5b). Tlie specimens represented are from Locality 54n, Middle Cambrian limestones in Blacksmith Fork Can- yon, east of Hyrum, Cache County, Utah. Figures 26A and 26A" are copied from Walcott [190Sd, PI. ^^I, figs. S and Sa]. Dorsal valve ratlier strDtigly convex for a species of this genus; the highest pan is at/ ■alaout the center of the shell, from whence the slope is very slight to the beak, and rather rapid to the front margin. Beak marginal above a low, broad arching of the posterior mar- gin of the shell; area slio-mi only by a veiy narrow margin where the shell bends toward the naedian line ; no trace of a pseudodel- tidium has been ob- served. Surface marked by narrow, rounded, concentric threadlike striae or ridges with short striae between them. Shell substance corneous. The average size of adult shells is S mm. long by about the same ■n^idth. Ohservations. — This is one of the larger species of the genus. 2Iicrojnitra (Paterina) superba (Walcott) occurs 16 feet (4.5 m.) below and Micromitra (Iphidella) pannula (White) 70 feet (21.3 m.) below in the same section. This fine shell has a short pseudodeltidium much like that of 31. (P.) Jogani (Walcott), but it differs in form and greater size; the same is true of M. (P.) crenistria (Walcott). It may be closelj" related to M. (P.) Jabradorica utahensis (Walcott), but the specimens of the latter are too imperfect for close comparison of foi'm. The specific name is given for my son, Benjamin Stuart Walcott, who assisted me m col- lecting the specimens during the summer of 1906. Formation and locality. — Middle Cambrian: (54n) About 5-50 feet (167.6 m.) above the Brigham quartzite and 3,640 feet (1,109.5 m.) below the Upper Cambrian, in the limestones forming 2e of the Ute limestone [Walcott, 1908f, p. 197], in Blacksmith Fork Canyon, about 10 miles (16.1 km.) east of HjTum, Cache County, Utah. MicEOMiTEA (Paterina) superba (Walcott). Text figures 27A-B; Plate II, figures 7, 7a-f. Iphideacrd.'? ornatella Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. S, pt. 1, PI. IV, figs: 6 and 7. (No text reference.) Iphidea superba Walcott, 1897, Proc. U. S. Nat. Mus., vol. 19, p. 711, PI. LIX, figs. 1, la-c. (Described. The speci- mens represented by figs. 1, la-c are redrawn in this monograph, PI. II, figs. 7c, 7, 7a, and 7b, respective!}'.) Ventral valve subcorneal, with a minute beak incurving over the pseudodeltidium. Car- dinal slope slightly flattened so as merely to indicate an imperfectly defined rather narrow false area. In some specimens the curvature of the shell is practically contmuous to the base of the pseudodeltidium. Pseudodeltidium broad, con- vex, with its lower margin broadly arched, so as to leave a considerable space between it and the line of the general plane of the sheU. Dorsal valve slightly con- vex; most elevated a little in front of the small beak which projects a little over the broad open space beneath it. Xo traces of a false area or pseudodeltidium have been observed. Figure 27 .— Micromitra (Paterina) superba (Walcott). A, A', Top and back views of ventral valve from Locality 54n, Middle Cambrian limestones in Blacksmith Fork Canyon, Cache County, Utah (U. S. Nat. Mus. Cat. No. 514S6). B, Side view of ventral valve showing pseudodeltidium, from Locality 5iy, at the same locality but from a shghtly lower horizon than that of the specimen represented by figures 27A-A' (U. S. Nat. Mus. Cat. No. 51491). 356 CMIBRIAN BRACHIOPODA. Surface with rather strong concentric stria?, and a few somewhat obscure lines of growth. On the ventral valve the striae extend around to and cross the pseudodeltidium. Shell sub- stance corneous. Observations. — This is one of the larger species of the genus, being surpassed in size only by Micromitra (Paterina) labradonca (Billings). It is clearly distinguishable from M. (P.) bella (Billings) by its larger size, more depressed ventral valve, and the form of the pseudo- deltidium. The dorsal valves of the two species are quite similar. It differs from M. pealei (Walcott) in its broad pseudodeltidium, false area, and surface markings. One specimen has a length of 9 mm. and a little greater width. The area is vertical, the pseudodeltidium being broken away. This species is represented by some fine specimens that occur in the lower part of the JMiddle Cambrian of northern Utah. Micromitra (Iphidella) pannula (White) occurs 54 feet (16.5 m.) lower in the section and M. (Paterina) stuarti Walcott 16 feet (4.5 m.) higher up. Formation and locality. — Middle Cambrian: (74) Sandstone about 300 feet (91.4 m.) above the base of the Tonto group, at the head o£ Nunkoweap Valley; (74d) sandstone beds in " Tonto " shale, just above massive sandstones near mouth of Bass Canyon, on the south side of the Grand Canyon; and (73a) "Tonto" sandstone in Chuar Valley; all in the Grand Canyon of the Colorado, Arizona. (54n) About 550 feet (167.6 m.) above the Brigham quartzite and 3,640 feet (1,109.5 m.) below the Upper Cam- brian in the limestone forming 2e of the Ute limestone; (54p) about 525 feet (160 m.) above the Brigham quartzite and 3,665 feet (1,127.1 m.) below the Upper Cambrian in the shale forming 2f of the Ute limestone; and (54y) about 510 feet (155.4 m.) above the Brigham quartzite and 3,680 feet (1,121.7 m.) below the Upper Cambrian in the lime- stones forming 2g of the Ute limestone; all in Blacksmith Fork Canyon [Walcott, 1908f, p. 197], about 10 miles (16.1 km.) east of Hyrum, Cache County, Utah. (Sj) About 575 feet (175.3 m.) above the unconformable base of the Cambrian in a shale which corresponds in position to shale No. 4 of the Dearborn River section [Walcott, 1908f , p. 202], on the ridge between Gordon and Youngs creeks, about halfway between Gordon Mountain and Cardinal Peak, Ovando quadrangle (U. S. Geol. Survey), Powell County, Montana. Specimens that are somewhat doubtfully identified with this species occur in the following locality : Upper Cambrian: (160) Sandstones forming a remnant of the Gallatin formation, which lies between the expo- sures of "porphyrite" on the east side of Willow Creek [Peale, 1896, areal geology sheet], 12 miles (19.2 km.) south- southwest of Threeforks, Threeforks quadrangle (U. S. Geol. Survey), Gallatin County, Montana. Micromitra (Paterina) undosa (Moberg). Text figures 28A-C. Kutorgina undosa Moberg, 1892, Geol. Foren. i Stockholm Forhandl. for 1892, Bd. 14, Hft. 2, p. 112, PL III, figs. 10-12. (Described in Swedish as a new species; see below for free translation. Figs. 10-12 are copied in this monograph as figs. 28C, 28A, and 28B, respectively.) Moberg describes this form essentially as follows : No specimen shows the umbonal part of the- ventral shell completely preserved, yet it seems as if the umbo had projected somewhat beyond the straight hinge margin. From the umbo the shell slopes gently in all directions, forming a rather feebly convex surface with even arch. The dorsal P valve is more flattened and less evenly arched than the ventral and more transverse, with the anterior corners evenly rounded off. The area is not quite distinctly preserved on any specimen; the . ~~" -^ Q beak is situated quite near the posterior edge ; it is sharply marked TiGUKE 28.-Micromitra (Pulerlna) undosa (Moberg). A, B, ^nd projects with a somewhat blunt point. The ornamentation of Ventral valves. C, Dorsal valve. the shell is very characteristic ; the strongly marked lines of growth The specimens represented by figures 2SA and 28B are appear to be formed of a row of small bows, and on some specimens from Locality 390a, drift blocks of Lower Cambrian sandstone there are fine, short, sharp, radiating, subordinate, depressed lines, at Stora Ror, Oeland Island; that represented by figure 28C -phe shell is quite thick, and, it is thought, formed of a hornlike is from Locality 390h, drift blocks of Lower Cambrian sand- , stone on Nordmannaskilr Island; both in Sweden. Figures substance. 28A-C are copied from Moberg [1892, PI. Ill, figs. 11,12, . j i- • a i t r and 10]. Figure 2SB may be selected as representing the TwO specimens of medium SlZe are 4 mm. and 3.5 typespecimen. mm. long and 5 mm. and 4.75 mm. broad, respectively. Judging by the fragments the sjjecies must have attained considerable size. PATERINID.E. 357 Ohservations . — Tliis form recalls Micromitra (Paterina) labradorica (Billings), wliicli is found in association with Discinella at Bio, Canada. The size and character of the shell indicate its relationsliip to Micromitra rather than to Kutorgina. Formation and locality. — Lower Cambrian: With Discinella in drift blocks of glauconitic quartzitic sand- stone at the following localities [Moberg, 1892b, pp. 112 and 115]; (310f) west of Ekerum; (390a) at several points near Stora Ror; (390d) north of Rohalla; and (390h) on Nordmannaskar Island; all in the Kalmar district of the Geological Survey of Sweden, Oeland Island, Sweden. Moberg [1892b, p. 11-t] describes some fragments which he refers to Kutorgina sp. From his statement that the fragments appear to be of a homy texture it is highly probable that they belong to the genus Micromitra. AIicROMiTRA (Paterina) wapta Walcott. Text figures 29A-B. Micromitra (Paterina) wapia Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, p. 59, PI. VII, fig. 6. (Described and discussed as below as a new species. Fig. 6 is copied in this monograph as fig. 29A.) Shell large and tliick for a species of this genus. Ventral valve depressed, conical, with the apex above a narrow false area that is outlined by the abrupt curvature of the shell. As the shells usually occur compressed in the siUceous shale, the false area is concealed and the posterior slopes from the apex form a blunt angle at the apex. Dorsal valve transverse, moderately convex, with the posterior margin nearly straight and a little shorter than the greatest width of the valve; beak small, marginal; cardinal slope and false area unknown. Surface marked by concentric, shghtly irregular, rounded lines and ridges of growth that are grouped in „ S ,r- „ . . ° J^ . != t^ Fia^TRE 29.— Micromitra (Paterina) wapta WtiicoU. A, bands ot Var3ing width; a few radiatmg striae or lines E.xteriorofventraIvalve,tlietypespecimen(U.S.Nat. occur on the central portions of one ventral valve ; with Mus.cat.No.5i4fl2a). b, portion of dorsal valve (u.s. . . ^ ' J«at. Mus. Cat. No. 51402b). a lens magnifvmg 20 diameters an occasional roughness . 1 T 1 r. specimens represented are from Locality 35c, a can be seen in reflected light on the surface of some ot drift Wock of Lower Cambrian shale on Mount Bosworth, flip fnnppntrip rirlcrps British Columbia. Figure 29A is copied from Walcott tne concentric riage=,. ^ ^ ^^^^^ p, ^^^^ ^^ ^^ Observations. — This is one of the largest species of the genus. One ventral valve has a length and breadth of 14 mm.; several are 9 to 11 mm. in diameter. It compares in size with Micromitra {Iphidella) nyssa, from the same geologic hori- zon in ]\Iontana, but the latter has a reticulate exterior surface of thel/. (7.) pannula type. It was al first thought that this species might be the old shells of Acrothele colleni Walcott, but a careful comparison with the younger stages of growth of M. (P.) wapta shows that the latter has only very indefinite traces of the highly ornate surface of Acrothele colleni and that the apex of the ventral valve of M. (P.) wapta is imperforate and over the posterior margin and not on the general surface of the valve in advance of the margin, as in Acrothele colleni. The two species were found associated on Mount Bosworth. M. (P.) wapta is of the same tj'pe as M. (P.) labradorica, M. (P.) prospectensis, and M. (P.) stissingensis. It differs from all in having more irregular, less definite threadlike concentric lines, and in the manner in which the stride are assembled in ridges. The specific name is derived from Lake Wapta, which lies a little to the west of the type locality. Fobmation and locality.— Lower Cambrian : (35c) Drift blocks of siliceous shale supposed to have come from the Mount Whyte forviation [Walcott, 190Sf, p. 214], found on the south slope of Mount Bosworth, a short distance northwest of the Canadian Pacific Railway track between Stephen and Hector, eastern British Columbia, Canada. (35e) About 270 feet (82.3 m.) below the Middle Cambrian, in a greenish siliceous shale correlated with No. 3 of the Mount ^^■hyte formation on Mount Bosworth [Walcott, 19081, p. 214], in the amphitheater between Popes Peak and Mount Whyte, about 3 miles (.4.8 km.) northwest of Lake Louise, southwest of Laggan on the Canadian Pacific Railway, Alberta, Canada. 358 CAIMBRIAN BRACHIOPODA. MicKOMiTEA (Paterina) williardi Walcott. Text figures 30A-E; Plate II, figures 9b-c. Iphidella major Walcott (in part), 1905, Proc. U. S. Nat. Mus., vol. 28, p. 304. (Specimens now referred to M. (P.) ivilliardi were included with the specimens representing M. (P.) major when this description was written.) Micromitra {Paterina) williardiVi alcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, p. 60, PI. VII, fig. 7. (Described and discussed as below as a new species. Fig. 7 is copied in this monograph as fig. 30A.) Ventral valve subconical, with the apex over the posterior third of the subcirciilar margin of the valve; false area narrow but clearly defined by a rather sharp angle on the cardinal slopes that breaks the curvature of the sliell a short distance from the margm of the pseudodeltidium; pseudodeltidium broad, con- vex, with its lower margin broadly arched so as to leave a space between it and the gen- eral plane of the margin of the shell. Some specimens of the pseudodeltidium are uniformly rounded, in others there is a narrow groove extending frpm the apex to the base, and on some a very narrow f amt ridge is indicated. Dorsal valve slightly con- vex, transverse, and slightly rounded at the cardinal margin. No traces of a false area or pseudodeltidium have been observed. The cast of the interior of the apex of the ventral valve shows a small apical callosity with two radiating grooves extending upward toward the front lateral margin of the shell. Surface marked by very fine, strong, concentric, elevated strise that in a specimen 10 mm. in diameter show seven elevated strias in a distance of 1 mm. ; the elevated strise are crossed by verj^ fine transverse strise ; the elevated strise cross the false area parallel to its base and arch over the pseudodeltidium. A ventral valve 10.5 mm. in diameter has a height of 2.5 mm. Oiservations. — This species is closely related to Micromitra {Paterina) superia (PI. II). It differs in having a longer pseudodeltidium, more finely elevated strise on the surface, and a more sharply elevated apex to the ventral valve. It is the Lower Cambrian representative of M. (P.) superha. The specific name is given in honor of Mr. T. E. WUliard, who collected the type specimen. Formation and locality. — Lower Cambrian: (17b) Rome ("Montevallo") formation, 4 miles (6.4 km.) south of Helena; and (56c) Rome {" Montevallo ") formation, 1.135 miles {l.Shm.) northeast of Helena; both in Shelby County, Alabama. Figure ZO.— MkromUra(,Paterina)u!iUiardi'\Valcott. A, A', A",Top, side, and back of apartly flattened ventral valve (U. S. Nat. Mus. Cat. No. 51482a). B, Pseudodeltidium with strong lines and ridges of growth (U. S. Nat. Mus. Cat. No. 514S2b). C, Pseudodeltidium with median furrow (U. S. Nat. Mus. Cat. No. 514S2c). D, A small dorsal valve (U. S. Nat. Mus. Cat. No.51482d). E, Enlargement of the outer surface near the front margin of a ventral valve, X 15 (U. S. Nat. Mus. Cat. No. 51482e). Figure 30A represents the type specimen. The specimens represented are from Locality S6c, 1.125 miles (1.8 km.) northeast of Helena, Shelby County, Alabama. Figure 30A is copied from Walcott [1908d, PI. VII, fig. 7). PATERINID^. 359 IPHIDELLA Walcott, a subgenus of MICBOMITRA. [IpMdea.] Kutorgina Walcott (in part) [not Billings], 1886, Bull. U. S. Geol. Survey No. 30, pp. 101-102. (Genus Kutorgina described, but description also includes reference to specimens now referred to Micromilra, Micromitra (Paterina), and Micromitra {Iphidella).) Kutorgina Hall and Clarke (in part) [not Billings], 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, pp. 90-94. (Copies Walcott's description, 1886b, pp. 101-102, and discusses genus, but description and discussion also include reference to specimens now refen-ed to ilia-omifra, Micromitra (Paterina), Micromitra {Iphidella), Protorthis, and Billingsella.) Iphidea Billings, Walcott (in part), 1897, Proc. IT. S. Nat. Mus., vol. 19, pp. 707-711. (Discussed. The genus as dis- cussed includes species now referred to Micromitra, Micromitra {Paterina), and Mia-omitra {Iphidella).) Iphidella Walcott (in pait), 1905, Proc. U. S. Nat. Mus., vol. 28, p. 304. (Merely proposed to replace Iphidea, but includes reference to specimens belonging with Micromitra, Micromitra {Paterina), and Micromitra {Iphidella).) Iphidea BilUngs, Gkabau and Shimee (in part), 1907, North American Index Fossils, vol. 1, p. 201. (Described and includes species referred to each of the subgenera Paterina and Iphidella.) Micromitra {Iphidella) Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 4, PI. XI, and pp. 142 and 143. (Classifica- tion of subgenus.) Iphidella was proposed to replace IpMdea, no species being given as the type. Micromitra Meek [1873, p. 479] has priority as the generic name, but as IpJiidella was intended to include the ornamental crenulated as well as plain type of surface, those species having the former type are now grouped under Iphidella as a subgenus of Micromitra. Type. — Trematis pannulus White. The species included in this subgenus and the description of their ornamented surfaces are given under the description of Micromitra (p. 336). ]MicEOMiTRA (Iphidella) LorisE Walcott. Text figures 31 A-B. Micromitra {Iphidella) Ionise Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, pp. 56-57, PI. VII, figs. 4 and 4a. (Discussed as below as a new species. Figs. 4 and 4a are copied in this monograph as figs. 31A and 31B, respec- tively.) In form tliis species is not unlike Micromitra pealei (PI. Ill, figs. 3, 3a-e) and the more elongate form of Micromitra {Iphidella) pannula muladensis (PI. IV, figs. 2, 2a-g). It differs from both forms mentioned in its surface characters. In the latter respect it is more Hke M. (7.) nyssa (PI. Ill, figs. 9, 9a), but the form of M. (I.) louise is more elongate and the apex of the ventral valve is nearer to the posterior margin; the shell also appears to have been thicker. The surface characters are exceedingly minute. Under a glass magnifying twenty diameters the surface looks much like that of the anterior half of Plate r\^, figure Is. The largest ventral valve in the collection has a yiavnESi.— Micromitra (TpMdeiia)iouiseWai- length of 7.5 mm. and a width of 7 mm. ; elevation, 1 mm. ^"- a, Flattened and partly distorted ven- '^ . . . . _ ' ' ^^ tralvalve,tlietypespecin;en(U. S.Nat. Mus. Micromitra (Iphidella) louise is the oldest known brachiopod cat. No. suoia.) b, side of laterally com- from the Cambrian of the Canadian Kocky lilountams. In the L'^Tuo^br''' ™'™ '''' ^' ^''' '^'^' ^"' Lakes Louise and Agnes section it is 3,150 feet (960.1 m.) The specimens represented are from the below the Middle Cambrian, and 2,760 feet (841.2 m.) below Lower Cambrian siliceous Late Louise shale, ,11- 1 • 1 • 1,1 ,1 1 • c ,1 . , at Locality 35d, on the north side of Lake the horizon winch is correlated on the basis of the associated Louise, Alberta, Canada. The figures are faunas with that at winch M. (/.) nyssa occurs in Montana, copied from waicott [i908d, pi. vn, figs. 4 It occurs in a fine, hard, dark-graj-, sihceous shale in association with Hyolithes, Cruziana, and a fragment indicating the free cheek of a trilobite. o The synonymy lor this subgenus does not give a complete record of the various genera under which the species now included in Iphidella were formerly placed; it includes only those references in which the subgenus is discussed or described. For the sake of completing the record the remaining mere generic references are here listed: Trematis White [1874, p. 6]. Iphidea Linnarsson [1876, p. 25]. Trematis White [1877, p. 36] . Kviargina Walcott [1887, p. 190; 1891a, p. 609]. Iphidea Schuehert [1897, p. 234). Iphidea Matthew [1902b, p. 110]. Iphidea Gronwall [1902, p. 40]. Kutorgiiia Pack [1906, p. 296]. 360 CAIvffiRIAN BRACHIOPODA. Tliis form owes its specific name to its occurrence on the shores of Lake Ijouise. Formation and locality. — Lower Cambrian: (36d) About 3,150 feet (960.1 m.) below the Middle Cambrian in the siliceous Lake Louise shale [Walcott, 1908f, p. 216] in cliff on the north side of Lake Louise, at its upper end, southeast of Laggan on the Canadian Pacific Railway, Alberta, Canada. MiCROMiTKA (Iphidella) nyssa Walcott. Plate III, figures 9, 9a. Micromitra (Tphidella) nyssa Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, p. 57, PI. VII, fig. 5. (Described and discussed as below as a new species. Fig. 5 is copied in this monograph, PL III, fig. 9.) Ventral valve subcircular in outline, with the posterior margin almost transverse; form depressed, conical, with a minute beak incurving over the pseudodeltidium. The cardinal slope is compressed in all the specimens, but it indicates that there was an imperfectly defined narrow area. Pseudodeltidium, as far as can be determined, broad and short, with its lower margin broadly arched. Dorsal valve slightly convex, beak marginal. No traces of a false area or pseudodeltidium have been obserA'^ed. Surface marked by concentric striae and Hnes of growth that are crossed obUquely by two sets of fine elevated lines. The crossing of the latter lines forms minute, shallow, rhomboidal pits, which give to the surface the appearance of a fine network. On the ventral valve the striaB cross the pseudodeltidium. Shell substance corneous. Ohservations. — This is one of the largest shells of this genus. The ventral valve has a length of 11 mm., width 13 mm. In form it resembles Micromitra (Paterina) labradorica (Billings) and in surface characters M. (Iphidella) ornatella (Linnarsson) and some varieties of M. (I.) pannula (White). Formation and locality. — Middle Cambrian: (4ci) About 315 feet (96 m.) above the unconformable base of the Cambrian and 190 feet (57.9 m.) above the top of the quartzitic sandstones, in a shale which corresponds in strati- graphic position to the upper part of shale No. 6 [see Walcott, 1908f, p. 202], on the ridge between Gordon and Youngs creeks, about halfway between Gordon Mountain and Cardinal Peak, Ovando quadrangle (U. S. Geol. Survey), Powell County, Montana. IMjcromitra (Iphidella) ornatella (Linnarsson). Plate III, figures 6, 6a-d. Iphidea ornatella Linnarsson, 1876, BUiang till K. svensk. Vet.-Akad. Handl., Bd. 3, No. 12, pp. 25-26, PL III, figs. 42a-e, 43a-c. (Described and discussed in English as a new species; see below for copy.) Iphidea ornatella Linnarsson, Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, pp. 97-98. (Mentioned in discussion of genus Iphidea.) Iphidea ornatella Linnarsson, Gronwall, 1902, Danmarks Geol. Unders0gelse, Rsekke 2, No. 13, p. 40. (Mentioned in Swedish.) The original description by Linnarsson follows: Shell small, transversely oval; sides and front rounded; hinge line straight, or nearly so, shorter than the width of the shell; cardinal angles rounded. Surface marked with retiform eminences, including small excavations. The eminences often swell out and become higher at the crossing points, thereby giving to the surface a somewhat granu- lated appearance (as in fig. 43). In some specimens there are also more or less distinct radiating ridges, especially near the median line of the shell. The shell substance is apparently corneous, but I have not been able to discern more than one layer. The color in the specimens from Bornholm is black, in those from Westrogothia more brown. Ventral valve convex, subconical. Beak erect and pointed, pierced by a minute round foramen. The posterior, visible only in one specimen, is truncated, so as to form a false area, which has in the middle a triangular fissure, arched over, in the upper part only, by a convex pseudodeltidium. Dorsal valve less convex, somewhat flattened along the middle; greatest height at the beak, which is not, however, so prominent as in the opposite valve. Hinge area not visible in any of the specimens. Interior of both valves unknown. Two specimens measured: Length 3 mm., breadth 4 mm.; and length 2 mm., breadth 3 mm. Linnarsson [1876, p. 26] speaks of the presence of a minute foramen, but after the study of several finely preserved ventral valves from the Paradoxides zone of Andrarum, Sweden, I am led to believe that what he considered to be an apical foramen is the minute longitudinal PATEKINIDyE. 361 furrow just in front of the beak, which is shown on the specimens before me and on otlier species as mentioned in the discussion of the genus Micromitra (p. 335). At first sight it is very difticult to determine whether tliere is an apical foramen or not, but with a strong light and a liigh power the furrow in M. (/.) omatella is seen to be smooth at the bottom and to show no trace of an opening down through the shell. The surface ornamentation is of the same type as that of M. (7.) -pannvla (Wliite). It differs in details, but the range of variation in tlie surface of M. (/.) pannula (Wlrite) is greater than the differences between its surface and that of M. (I.) omatella. The most marked distinction between the two species is in the form of the false area and pseudodeltidium of the ventral valve; the dorsal valve of M. (/.) pannula also appears to be more elevated. These differences, however, might disappear if we had a large number of specimens of M. (7.) omatella for comparison. With the material we now have they appear to be of specific value. One specimen from Andrarum shows a narrow area on each side of the wide, low, triangular openiag, the pseudodeltidium being broken away. Shell substance corneous. Formation and locauty. — Middle Cambrian: (8w) Limestones of the Paradoxides forchhammeri zone, at An- drarum, 20 miles (32.2 km.) northwest of Simrishamn, Province of Christianstad ; (320f) limestone at Andrarum, 20 miles (32.2 km.) northwest of Simrishamn, Province of Christianstad; (320n) livwstonesof the Paradoxides forchhammeri zone at Lovened, Djupadal, 19 miles {30.6 km.) south-southeast ofShara, Province of Skaraborg; and (320y) limestones of the Para- doxides forchhammeri zone at Gudhem, 12.5 mUes (20.1 km.) south-southeast of Skara, Province of Skaraborg; all in Sweden. (324c) Shales of Etage Id [Brogger] at Krekling, in Sandsvar, Norway. (16h) Limestones of the Paradoxides forchhammeri zone at Borregaard, Bomholm Island, Denmark. (6g) Limestone near the base of the Middle Cambrian, the lowest horizon carrying Paradoxides, northwest side of Chappie Arm Harbor, about 1 mile (1.6 km.) from its head, Trinity Bay, Newfoundland. Micromitra (Iphidella) pannula (White). Text figure 32, page 362; Plate IV, figures 1, la-t, 3, 3a. Tremxitis pannulusWrnTE, 1874, U. S. Geog. Surveys W. lOOthMer., Prelim. Kept., p. 6.- (Described as a new species.) Trematis pannulus White, 1877, idem. Final Rept., vol. 4, pt. 1, pp. 36-37, PL I, figs. 4a and 4b. (Described and discussed. The specimen represented by figs. 4a and 4b is redrawn in this monograph, PL IV, fig. Ig.) Kutorgina pannula (White), Walcott, 1886, Bull. U. S. Geol. Survey No. 30, p. 105, PL VII, figs. 3, 3a; PL VIII, figs. 2, 2a-c. (Copies the description and discussion given by WTiite, 1877, pp. 36-37. PL VII, figs. 3 and 3a, are drawn from the specimen figured by \\'hite, 1877, PL I, figs. 4a and 4b. The three specimens represented by figs. 3 and 3a, 2 and 2a, and 2b and 2c are redra^vn in this monograph, PL IV, figs. Ig, Ij, and Ik and Ip, respectively.) Kutorgina pannula (White), Walcott, 1887, Am. Jour. ScL, 3d ser., vol. 34, p. 190, PL I, figs. 14, 14a-b. (Character- ized from a new locality. The two specimens represented by figs. 14 and 14a and fig. 14b are redrawn in this monograph, PL IV, figs. Im and Iq and figs. Ik and Ip, respectively.) Kutorgina pannula (White), Walcott, 1891, Tenth Ann. Rept. U. S. Geol. Survey, p. 609, PL LXIX, figs. 5, 5a-f. (Mentioned. Figs. 5, 5a, and 5b are copied from Walcott, 1886b, PL VIII, figs. 2a, 2, and 2b; figs. 5c, 5e, and 5f from Walcott, 1887, PL I, figs. 14, 14b, and 14a; and fig. 5d from Walcott, 1886b, PL VII, fig. 3. The six specimens represented by figs. 5 and 5a and 5b-f are redrawn in this monograph, PL IV, figs. Ij, Ik, Im, Ig, Ip, and Iq, respectively.) Iphidea pannulus (White), Schuchert, 1897, Bull. U. S. Geol. Survey No. 87, p. 234. (Merely changes generic ref- erence.) Iphidea pannula (White), Matthew, 1902, Trans. Roy. Soc. Canada for 1902, 2d ser., vol. 8, sec. 4, No. 3, p. 110. (Char- acterized from a new locality.) Iphidella pannula (White), Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 307. (Merely changes generic reference.) Kutorgina pannula (White), Pack, 1906, Jour. Geol., vol. 14, No. 4, p. 296, PL II, figs. 1, la-c. (Discussed. Figs, lb and Ic are outline drawings after Walcott's figures, 1886b, PL VIII, figs. 2a and 2b; fig. la is an outline draw- ing after Walcott's figure, 1891a, PL LXIX, fig. 5d.) Iphidea pannulus (^\1iite), Grabau and Shimer, 1907, North American Index Fossils, vol. 1, p. 201. (Described.) Micromitra (Iphidella) pannula (White), Walcott, 1908, Canadian Alpine Journal, vol. 1, No. 2, p. 244, PL I, figs. 1, la-c. (No text reference. Figs. 1, la-c are copied in this monograph, PL IV, figs. Ir, le. Id, and Iq, respec- tively.) Ventral valve conical; beak slightly incurving over the pseudodeltidium. Cardmal slopes rounded and flattened so as to form a not very strongly defuied false area on each side of the wide, triangular opening, wliich is crossed toward the summit by a low, highly rounded pseudo- 362 CAJMBRIAN BRACmOPODA. deltidium; the latter projects directly outward at right angles to the false area and then curves abrupt!}', so as to be almost flat across the center. A narrow, slight median groove extends from beneath the apex to the posterior margin. Another specimen shows a portion of a pseudo- deltidium that is somewhat less elevated than the one described. The apex of the valve just outside of the extreme point of the beak is crossed by a very minute longitudinal depression that is visible only under a strong magnifier. Dorsal valve slightly convex, sloping regularly from the front margin to the small beak, which is sHghtly incurved at the margin of the valve. False area clearly defined; in a speci- men 10 mm. in width the area has a width of a little over 1 mm. at the side, narrowing to a point at the apex. It is broken midway by a wade triangular opening, which is filled in by a depressed pseudodeltidium. The sides of the deltidium turn in at nearly a right angle for a short distance to the general plane of the pseudodeltidium, which extends across from side to side. Posterior margin slightl}' arched, and its general surface broken midway by a narrow, distinct groove, which extends from beneath the beak back to the posterior margin. (See PI. IV, fig. If.) Strise of growth extend across the false areas and pseudodeltidia in both valves; shell substance corneous. The surface ornamentation of this species is as liighly ornamental as that of any Cambrian brachiopod. It appears to be formed of a very fine network of oblique raised lines, which divide it up into minute diamond-shaped pore- like pits, a surface wliich resembles, under a strong lens, the texture of finely woven cloth. A closer examination, however, of some of the larger shells shows, on the outer margin, cren- ulated concentric lines, and a little farther back on the shell more deeply crenulated lines; still farther back the points of the crenulations unite so as to form a solid network that gives the appearance of oblique lines crossing at nearly right angles (PI. IV, fig. Is). The surface marking is so strongly char- acteristic that the presence of the species has been detected a number of times by finding very small fragments of the sheU. It not in- frequently happens that in old shells the sur- face characters have been almost entirely worn away, traces of the ornamentation remaining The wearing of the surface near the umbo is shown FiGmiE 32. — Micromitra {IphideUa) pannula (AVhite). Ventral valve, showing setae, from Locality 35k, Middle Cambrian, Burgess shale member of the Stephen formation, near Field, British Columbia. This specimen is unique in being the first Cambrian brachiopod in which the setae have been obser\-ed. The preser\'ation of so frail a portion of the anatomy of the brachiopod is no more remarkable, however, than the presence in the same shales of annelids showing the fringe of setse around the mouth: of crustaceans of many kinds showing the braDchiae and appendages; of trilobites with anteimse, brancluEe, legs, etc.; of holothurians showing the podia and the dental plates: of medusEe, sponges, etc. — a fauna which is now being described and figured in volimie 57 of the Smithsonian Miscel- laneous Collections. only in the vicinity of the cardinal slopes. in Plate IV, figure Im. In some specimens fi-om Montana (PI. IV, fig. Is) the surface is most beautifully pre- served, and at fu'st glance there appears to be a specific difference between it and the specimens from Mount Stephen, central Nevada, and the Colorado Canyon. This may be seen by com- paring figures Ir and Is (PI. IV). There are, however, intermediate forms that possess more or less of the characteristics shown by the two figures. In some specimens there are fine, radiating undulations extending from the apex to the margin that give to the shell an appear- ance much like that of the young of M. sculptilis (Meek) and M. (Paterina) stissingensis (Dwight) . These are finely shown by Plate IV, figure In. The surface ornamentation is much like that of M. (Iphidella) ornatella (Linnarsson) of Sweden. It differs but slightly in the form of the depression formed by the union of the crenulated striae. This species has a wide geographic distribution, and it also occurs both in the Lower Cam- brian in the Olenellus fauna, and in the Middle Cambrian in the Olenoides fauna. Its range in PATERINID.E. 363 the West is from Nevada to Montana, and in the Appalachian region from eastern New York to Alabama. At fu-st, on account of its higlily ornamented surface, I was led to think that it might belong to a distinct genus from Micromitr^,, but comparisons with M. sculptilis (Meek) and the simple ornamentation of M. (Paterina'; beUa (Billings) show transitions in the orna- mentation between the otherwise distinct forms. Varieties of Micromitra (Iphidella) pannula. — In collections from the Middle Cambrian limestones of northern Utah and southern Idaho, material has been selected for illustration which represents varieties of form and surface markings of Micromitra (Iphidella) pannula (White) that might be given specific names were it not for the intermediate phases which occur at the same locality with the varieties. The specimens from near Malade, Idaho (PI. IV, figs. 2, 2a-g), and many not illustrated, show a wide variation in outline and surface. Another series from near Ophir, Utah (PI. IV, figs. 4, 4a-f), illustrate the entire evolution of the "pannula" type of surface, from the concentric strife' to the fine network of oblique, raised lines dividing the surface into minute, diamond-shaped depressions. In some of the examples from Malade the ridges are so sharp and clear that the surface has a honeycomb-hke appearance (PL IV, fig. 2g). The surface of M. (/.) pannula (White) is composed of porelike pits formed bj' obliquely crossing, elevated lines (PI. IV, figs. In-ls), and for convenience of reference the forms sho-wing variations from this ma}' be separated into the Yurieties maladensis and opMrensis (pp. 364-365). Formation and locality. — TTpper Cambrian: (96) Limestones near the ford on the Cedartown road, 1.5 miles (2.4 km.) south of Rome, Floyd County, Georgia. Middle Cambrian: (14s) About 2,300 feet (701 m.) above the Lower Cambrian and 2,700 feet (823 m.) below the Upper Cambrian, in the Ogygopsu zone of the Stephen formation [W^alcott, 1908f, p. 210], at the "fossil bed," on the northwest slope of Mount Stephen, above Field on the Canadian Pacific Railway; (57j) about 2,000 feet (609.6 m.) above the Lower Cambrian in the limestones forming 2 of the Stephen formation [Walcott, 190Sc, p. 237 (6)], just east of the "fossil bed" on the northwest slope of Mount Stephen, above Field on the Canadian Pacific Railway; (58j) about 1,900 feet (579 m.) above the Lower Cambrian near the base of the limestone forming 2 of the Stephen formation [Walcott, 1908c, p. 238 (7)]; on the east side of Mount Stephen about 3,000 feet (914 m.) above the Canadian Pacific Railway track, 3 miles (4.8 km.) east of Field; and (3Sk) Burgess shale member of the Stephen formation on the west slope of the ridge between Mount Field and Wapta Peak, 1 mile (1.6 km.) northeast of Burgess Pass, above Field; all in British Columbia. (57g) About 1,700 feet (518 m.) above the Lower Cambrian and 3,250 feet (991 m.) below the Upper Cambrian in the siliceous shales forming 2d of the Stephen formation [Walcott, 1908f, p. 211], on Mount Bosworth, north of the Canadian Pacific Railway between Hector and Stephen, on the Continental Divide between British Columbia and Alberta, Canada. (4c[ and 4q') 315 and 310 feet (96 and 94.5 m.), respectively, above the unconformable base of the Cambrian and 190 and 185 feet (57.9 and 56.4 m,), respectively, above the top of the quartzitic sandstones in shales and limestones which correspond in position to the upper part of shale No. 6 of the Dearborn River section [see '\\'alcott, 190Sf, p. 202], on the ridge between Gordon and Youngs creeks, about halfway between Gordon Mountain and Cardinal Peak, Ovando quadrangle (U. S. Geol. Survey), Powell County; (302t) limestone northeast of Logan, Threeforks quadrangle (U. S. Geol. Survey), Gallatin County; and (149a) limestone at the forks of Pole Creek, above Cherry Creek basin, Threeforks quadrangle (U. S. Geol. Survey), Madison County; all in Montana. (55c and 163) « Spence shale member of the Ute limestone [W^alcott, 1908a, p. 8], about 50 feet (15.2 m.) above the Brigham quartzite and 2,755 feet (839.7 m.) below the Upper Cambrian, in a ravine running up into Danish Flat from Mill Canyon; and (59f) limestones immediately underlying the Spence shale member of the Ute limestone [Walcott, 1908a, p. 8], in a saddle north of the creek which flows into Mill Canyon from the west; both about 5 miles (8 km.) west-southwest of Liberty and 15 miles (24.2 km.) west of Montpelier, Bear Lake County, Idaho. (5b and 54s) Dark blue-gray Langston limestone [Walcott, 1908f, p. 198] just above the Cambrian quartzitic sandstones, north side of Twomile Canyon, near its mouth, 2 miles (3.2 km.) southeast of Malade, Oneida County, Idaho. (31v) 650 feet (198 m.) above the Lower Cambrian and 3,750 feet (1,143 m.) below the Upper Cambrian, in shales at the top of the limestone forming la of the Howell formation [Walcott, 1908f, p. 182], northeast side of Dome Canyon, about 4 miles (6.4 km.) west-southwest of Antelope Springs; and (31s) 490 feet (149.4 m.) above the Lower Cambrian and 3,925 feet (1,196.3 m.) below the Upper Cambrian, in the pinkish, argillaceous shale foi-ming Id of the Howell for- mation [V\^alcott, 1908f, p. 182], south side of Dome Canyon, about 1 mile (1.6 km.) below the divide and 3 mil pa (4.8 km.) west-southwest of Antelope Springs; both in the House Range [Walcott, 1908f, PL XIII], Millard County, LTtah. (14t) Limestone lying on the slope between the Cambrian quartzite and the massive blue limestone 100 feet (30.5 m.) above. Mount Nebo Canyon, 3 miles (4.8 km.) southeast of Mona, Juab County; (55u) limestones about 200 a This species also occurs in Locality 65e. 364 CAIvIBKIAN BRACHIOPODA. feet (61 m.) above the Lower Cambrian [see Walcott, 1908f, p. 171], 0.25 mile (0.4 km.) below the Maxfleld mine, in Big Cottonwood Canyon, on the west front of the Wasatch Mountains southeast of Salt Lake City, Salt Lake County; (30a) shale on the north side of Big Cottonwood Canyon, 1 mile (1.6 km.) below Argenta,, in the Wasatch Mountains southeast of Salt Lake City, Salt Lake County; and (541) about 500 feet (152.4 m.) above the Brigham quartzite and 3,700 feet (1,127.8 m.) below the Upper Cambrian in the Spence shale member of the Ute limestone [Walcott, 1908f, p. 197], in Blacksmith Fork Canyon, about 10 miles (16.1 km.) east of Hyrum, Cache County; all in Utah. (31) Shales at the Chisholm mine; and (333 [Pack, 1906, p. 296]) shales at the Abe Lincoln mine; both on the southwest slope of the Ely Mountains, 3 miles (4.8 km.) northwest of Pioche, Lincoln County, Nevada. (73a) "Touto" sandstone in Chuar Valley; and (74) sandstone about 300 feet (91.4 m.) above the base of the Tonto group, at the head of Nunkoweap Valley; both in the Grand Canyon of the Colorado, Arizona. (14) Limestones overlj'ing the sandstones of the Rome formation, near the wagon road and in a quarry near the railroad track, 7 miles (11.2 km.) southwest of Rome, Floyd County, Georgia. (101) Rogersville shale, just above the road iu the hill west of the schoolhouse, 3.5 miles (5.6 km.) southwest of Rogersville on the road to Melinda Ferry [Keith, 1896a, areal geology sheet], Hawkins County, Tennessee. Lower Cambrian: (57r and 58s) About 150 feet (46 m.) below the Middle Cambrian near the base of the limestones formmg 3 of the Mount Whyte formation [^Valcott, 1908c, p. 241 (10)]; and (35f)a about 300 feet (91 m.) below the Middle Cambrian in the limestone forming 6 of the Mount Whyte formation fWalcott, 1908c, p. 242 (11)]; both just above the tunnel on the north shoulder of Mount Stephen, about 3 miles (4.8 km.) east of Field, British Columbia, Canada. (41) Limestone in the Pioche shale [Walcott, 1908a, p. 11], on a ridge 2.5 miles (4 km.) northwest of the town of Cherry Creek, "Wliite Pine County; (30) limestone 8 miles (12.8 km.) north of Bennetts Spring, on the west slope of the Highland Range, Lincoln County; and (31a) limestone interbedded in the Pioche shale [Walcott, 1908a, p. 11], jibst above the quartzite on the east side of the anticline, near Pioche, Lincoln County; all in Nevada. (34) Limestone on roadside a little west of the bridge over Poultney River at Low Hampton, about 5 miles (8 km.) east-northeast of Whitehall, Whitehall quadrangle (U. S. Geol. Survey), Washington County; (38a) lime- stone 2 miles (3.2 km.) south of North Granville, on the road which turns south from the road running between that village and Truthville, 4 miles (6.4 km.) west-northwest of Granville, Fort Ann quadrangle (U. S. Geol. Survey), Washington County; and (44b) limestone near North Chatham in the northern part of the Kinderhook. quadrangle (U. S. Geol. Survey), Columbia County; all in New York. (4v) About 200 feet (61 m.) above the unconformable base of the Cambrian and 75 feet (22.9 m.) above the top of the quartzitic sandstones in a shale which corresponds in stratigraphic position to shale No. 6 of the Dearborn River section [Walcott, 1908f, p. 202], Gordon Creek, 6 miles (9.6 km.) from South Fork of Flathead River, Ovando quadrangle (U. S. Geol. Survey), Powell County, Montana. Specimens that are somewhat doubtfully referred to this species occur at the following localities : Middle Cambrian: (55c) Spence shale member of the Ute limestone [Walcott, 1908a, p. 8], about 50 feet (15.2 m.) above the Brigham quartzite, and 2,755 feet (839.7 m.) below the Upper Cambrian, in a ravine running up into Danish Flat from Mill Canyon, about 6 miles (9.6 km.) west-southwest of Liberty and 15 miles (24.2 km.) west of Montpelier, Bear Lake County, Idaho. (54(i) A drift block supposed to have come from the horizon of Locality 32x, a horizon correlated with the shales forming 2d of the Bloomington formation in Blacksmith Fork Canyon [Walcott, 1908f, p. 195], in Wasatch Canyon, east of Lakeview ranch, about 5 miles (8 km.) north of Brigham, Boxelder County, Utah. (13k) Shales of Matthew's [1903, p. 15] Coldbrook, above the great falls in Dugald Brook, Indian River, eastern Cape Breton, Nova Scotia. IVliCEOMiTEA (Iphidella) pannxila maladensis (Walcott). Plate IV, figures 2, 2a-g. Iphidella pannula maladensis Walcott, 1905, Proc. U. S. Nat. Mus,, vol. 28, p. 306. (Characterized as a new variety.) Surface covered with elevated, sharp, distinct ridges that give it an irregular, honeycomb- like appearance. This form owes its varietal name to its occurrence near Malade, Idaho. Formation AND LOCALITY.— Middle Cambrian: (5b) Dark blue-gray Langston limestone [Walcott, WOSb, p. 19S] just above the Cambrian quartzitic sandstones, on the north side of Tiuomile Canyon, near its mouth, 2 miles {3.2 km.) southeast of Malade, Oneida County, Idaho. (6g) Limestone near the base of the Middle Cambrian, the lowest horizon carrying Paradoxides, northwest side of Chappie Arm Harbor about a mile (1.6 km.) from its head. Trinity Bay, Newfoundland. a This species is somewliat doubtfully identified from this locality. PATERINID^. 365 MicROMiTRA (Iphidella) panntjla ophirensis (Walcott). Plate IV, figures 4, 4a-f. Iphidella pannula ophirensis Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 306. (Characterized as a now variety.) Surface formed by raised, concentric lines and ridges that inosculate and become more and more irregular until the tj^pical surface of Micromitra {Iphidella) pannula is developed. This form owes its rarietal name to its occurrence at Ophir, Utah. FoRM-\TioN AND LOCALITY. — Middle Cambrian: (3e) Thin-bedded limestones less than 400 feet (121.9 m.) above the quartzitic sandstones of the Cambrian, near Ophir, Oquirrh Range, Tooele County, Utah. Shells that I can not separate from this variety occur at the following localities: ' Middle Cambrian: (3x) About 2,200 feet (670.6 m.) above the Lower Cambrian and 2,200 feet (670.6 m.) below the Upper Cambrian, in the limestone forming Id of the Marjum limestone [Walcott, 1908f, p. 180], 2.5 miles (4 km.) east of Antelope Springs, in ridge east of ^Tieeler Amphitheater; and (llo) about 2,750 feet (838.2 m.) above the Lower Cam- brian and 1,650 feet (502.9 m.) below the Upper Cambrian, in limestone at the base of la of the Marjum lime- stone [Walcott, 1908f, p. 179], about 4 miles (G.4 km.) southeast of Antelope Springs, in the spur at the junction of the Deseret and Swasey Spring roads; both in the House Range [^'alcott, 190Sf, PI. XIII], Millard County, LTtah. (54s) Dark blue-gray Langston limestone [Walcott, 190Sf, p. 198], just above the Cambrian quartzitic sandstones, on the north side of Twomile Canyon, near its mouth, 2 miles (3.2 km.) southeast of Malade, Oneida County, Idaho. (14s) About 2,300 feet (701 m.) above the Lower Cambrian and 2,700 feet (823 m.) below the Upper Cambrian, in the Ogygopsis zone of the Stephen formation [Walcott, 190Sf, p. 210], northwest slope of Mount Stephen, above Field on the Canadian Pacific Railway, British Columbia, Canada. Fragments of shells that are not to be separated by their surface characters from Micro- mitra {Iphidella) pannula ophirensis occur in China. The fragments also indicate that the shells were about the same size and form. Middle Cambrian: (C5) Lower limestone member of the Iviulung group [Blackwelder, 1907a, pp. 37 and 39], 3.2 miles (5.1 km.) southwest of Yenchuang, Sintai district, Shantung, China. Genus VOLBORTHIA von Mbller.a Volborthia von Holler, 1874, Neues Jahrb. fiir Mineralogie, pp. 449^52. (Described and discussed in German as a new genus; see below for free translation of description on pp. 449-451.) Acrotreta {Volborthia) {von MoUer), Oehlert, 1887, Manuel de conchyliologie, by Fischer, p. 1266. (Described in French as a subgenus, with figures of "Acrotreta ( Volborthia) recurva (Kutorga).") Volborthia von Moller, Hall and Clarke, 1892, Eleventh Ann. Rept. State Geologist New York for 1891, p. 249. (Described.) Volborthia von Moller, Hall and Clarke, 1892, Forty-fifth Ann. Rept. New York State Mus. for 1891, p. 565. (Copy of preceding reference.) Volborthia von Moller, Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, pp. 95-96. (Original description, von Moller, 1874, pp. 449-451, translated essentially as below and genus discussed.) Volborthia von Moller, Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 4, PI. XI, and pp. 142 and 143. (Classifi- cation of genus.) The description in substance by von Moller [1874, pp. 449-451] is as follows: The shells remind one in their form of a broad horn whose opening is closed through a very convex cover (the dorsal valve). Seen from above, the outline of the figured shell, in consequence of the rounded edges and the likewise rounded front edge, is transversely oval. Only the posterior edge, whose length is about one-half of the breadth of the shell, appears straight. The ventral valve is very high, conical, and has a strong, recurved, prominent beak without any perforation. Between the beak and the hinge line (posterior edge) is a distinctly marked and high three-cornered area, whose length is divided by a narrow ridge extending from the beak to the middle of the straight hinge line. The dorsal valve is convex, nevertheless decidedly lower than the ventral, and it has just such a beak as the other. Although this beak lies in the same vertical line with that of the opposite valve, it nevertheless touches the hinge line of the shell, without any area lying between. The siirface of both valves is smooth and covered only with very fine concentric growth stria, which extend without interruption also over the area of the ventral valve. On the latter they appear much coarser and not so regular, especially on the ridge where these striae are rather strongly bent downward toward the beak of the ventral valve. Neither the ventral nor the dorsal valves appear to have inward projections; at least the casts (molds) show not the slightest traces thereof. Likewise the muscle scars are not known, and on the casts are usually found only a small a Prior to the deflnition of Volborthia by von Moller [1S74, p. 449] the species now referred to this genus was placed under Acrotreta Kutorga (1848, p. 277]. 366 CAMBRIAN BRACHIOPODA. number of widely separated radial lines. As regards the substance of the shell, it must be remarked that it is exactly the same as in the genus Siphonotrcta, i. e., calcareous-horny, and of a brown color. Under the microscope, enlarged six to eight times, the valves show a fine but distinct puncturing, invisible to the unaided eye. As regards the duiiensions of the shell, the largest examples have a length of 14, a breadth of 19, and a thickness of 16 mm., while the height of the ventral valve is 10 mm. Hall and Clarke [1892c, p. 96] compare this genus with Kutorgina on account of the general form and surface characters, and call attention to the presence of an areal ridge similar to that of "'Iplvidea" = Micromitra. The authors were under the impression tliat an apical foramen existed in Micromitra and probably in Volhorthia and that the areal ridge was the "ecurved" foramen scar. I do not find a foramen in Micromitra, and none has been seen in VolhortMa. The areal ridge appears to be the arched pseudodeltidium, both in Micromitra [PI. Ill, fig. 3b] and Volhorthia [PI. I, fig. 6e]. The previously published illustrations of Volhorthia recurva do not show any opening between the posterior margins of the valves, but that there was an opening for the passage of the pedicle is shown in figures 33A and 33 A'. The absence of defined muscle scars and vascular markings is a characteristic of this genus. The generic name was given in honor of Dr. A. von Volborth. Type. — Acrotreta recurva Kutorga. VOLBOETHIA EECUBVA (KutOrga). Text figures 33A-B; Plate I, figures 6, 6a-e. Acrotreta recurva KVTOII.Q A, 1848, Verhandl. Russ.-kais. min. Gesell. St. Petersburg for 1847, No. 12, pp. 277-278, PL VII, figs. 9a and 9d. (Characterized and discussed in German as a new species. The description of PI. Vil gives the name of the species as "Acrotreta incurva." The only flgm'es accompanying the reference are those men- tioned, 9a and 9d.) ^ Figure 33.— Volhorthia recurva (Kutorga). A, Posterior view of specimen figured by von Moller, 1874, PI. VII, figs. 1-6. A', Enlargement of same to show pedicle opening, light from the right. B , Posterior view of an associated ventral valve showing crenulation of the stri^ on the false area. The specimens represented are from Locality 336g, limestone in the vicinity of Zarskoe Selo, Russia. The specimens are now in the museum at Reval, but a cast of the type specimen represented in figures 33A-A' is in the. collections of the U, S. National Museum, Cat. No. 58298. Volhorthia recurva (Kutorga), von Moller, 1874, Neues Jahrb. fiir Mineralogie, pp. 449-452, PI. VII, figs. 1-6. (The description and discussion of the species is included in that of the genus, which is in German and which is trans- lated on pp. 355-356. Figs. 1-6 are copied in this monograph, PI. I, figs. 6, 6a-e, respectively. The specimen represented by figs. 6, 6a-e of von Holler's paper is redrawn in this monograph, figs. 33A-A'.) Volhorthia recurva (Kutorga), Hall and Clarke, 1892, Eleventh Ann. Kept. State Geologist New York for 1891, figs. 261 and 262, p. 249. (No text reference. Figs. 261 and 262 are copied from von Moller 1874, PI. VII, figs. 2 and 6, respectively.) Volhorthia recurva (Kutorga), Hall and Clarke, 1892, Forty-fifth Ann. Rept. New York State Mus. for 1891, figs. 261 and 262, p. 565. (Copy of preceding reference.) Volhorthia recurva (Kutorga), Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, pp. 95-96, figs. 52 and 53. (The description of the species is included in that of the genus, which is translated, essentially as on pp. 355-356 of this monograph, from von Moller, 1874, pp. 449^51. Figs. 52 and 53 are copied from von Moller, 1874, PI. VII, figs. 2 and 6, respectively.) The generic description includes the important characters of this, the only known species. Formation and LocALrrY. — Ordovieian: (336g [Kutorga, 1S4S, p. 278]) Limestone in the vicinity of Zarskoe Selo; and (337j [Fr. Schmidt, personal communication, 1908]) zone Blllfr or BIII/3, characterized by Asaphus raniceps, a little above the zone with Asaphus expansus, at Obuchow (Obookhov), on Wolchow River; both in the Government of St. Petersburg, Russia. PATERINID^. 367 Genus HELMEBSENIA Pander. Siphonotreta Jeremejbw, 1856, Verhandl. Russ.-kais. min. Gesell. St. Petersburg for 1855-6, No. 2, pp. 73 and 80. (New species S. ladogensis described in German.) Helmersenia Pander, 1861, Bull. Acad. imp. sci. St.-P6tersbourg, vol. 3, columns 48-49. (Jeremejew's species described and discussed in German.) Helmersenia Pander, Zittel, 1880, Handbuch der Palaeontologie, Bd. I, Abth. 1, p. 666. (Described in German.) Keyserlingia Kaepinsky, 1887, Bull. Acad. imp. sci. St.-P^tersbourg, vol.31, p. 476, footnote. (The use of Keyser- lingia in this footnote is clearly a typographical error, Helmersenia being intended. The genus is discussed in German.) Helmersenia Pander, Oehlert, 1887, Manuel de conchyliologie, by Fischer, p. 1264. (Described in French, see p. 369.) Helmersenia Pander, Hall and Clarke, 1892, Eleventh Ann. Kept. State Geologist New York for 1891, p. 254. (Described.) Helmersenia Pander, Hall and Clarke, 1892, Forty-fifth Ann. Kept. New York State Mus. for 1891, p. 570. (Copy of preceding reference.) Helmersenia Pander, Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, p. 119. (Copies Hall and Clarke, 1892a, p. 254, and discusses genus.) Helmersenia Pander, Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 4, PI. XI, and pp. 142 and 143. (Classi- fication of genus.) General form longitudinally ovate, subcircular to transversely ovate, with the ventral valve broadly subacuminate and dorsal valve broadly rounded except at the minute beak; ventral valve moderately convex, rising on the umbo and sloping most rapidly down to the minute, nearly marginal beak; dorsal valve gently convex with apex marginal. The interior of the ventral valve shows a narrow area with a thickened median ridge ex- tending a short distance forward to the visceral area. The latter has the general form of the visceral area of Oholus, with the muscle scars in front on each side of the center. One specimen shows the central and the outside and middle lateral scars; beneath the area, at the base of the median ridge, the main vascular sinuses arch outward and then forward; between the vascular sinus and the outer margin of the shell there are indications of the transmedian and anterior lateral muscle scars. The interior of the dorsal valve shows a slender median ridge extending well forward into the valve, and the main vascular sinuses well out toward the side of the shell. None of the specimens show the muscle scars of this valve, and I have not been able to find more than the broken margin of the area. Surface marked by concentric striae and a few stronger lines of growth. Scattered irreg- ularly over the surface on the epidermal layer there are elongate bases of numerous slender spines that closely resemble the bases of the spines of Siphonotreta verrucosa (Eichwald). The inner surface is minutely punctate with a few larger scattered punctse. The shell varies in size from 2 to 3 mm. in diameter. It rarely exceeds 2 mm. TypCf — Siphonotreta ladogensis Jeremejew. From Pander's remarks [1861, p. 48] in describing the genus Helmersenia it is evident that he considered the shells described by Jeremejew [1856, p. 73] as Siphonotreta ladogensis as belong- ing to this genus. As pointed out by Karpinsky [1887, p. 476] the form studied by Pander differs from S. ladogensis in being more circular in outline. I strongly suspect, however, that if the types of S. ladogensis were compared with the material used by Pander they would be found to be specifically identical. The figures given by Jeremejew [1856, p. 73] in my opinion represent young shells of the form subsequently named by Karpinsky. Tlirough the courtesy of Dr. Fr. Schmidt, of the Geological Survey of Russia, I have had the opportunity of studying specimens of Helmersenia collected by Karpinsky at Kunitz, in the Government of Pskow. I also received from Dr. A. Mickwitz some fine specimens collected at Koporje, in the Government of St. Petersburg. With the specimens from Kunitz there some- what rarely occurs Keyserlingia huchi (de Verneuil) and large numbers of Oholus (Sclimidtia) celatus Volborth. The associated forms at Koporje are Oholus (S.) celatus and fragments of a larger Oholus. Pander [1861, p. 48] describes the ventral valve of this species as having at the top of the beak a circular opening that does not, as in the " Siphonotretem.," extend into a canal. I have carefully studied with a strong lens more than one hundred specimens of the ventral valve of 368 CMIBRIAN BRACHIOPODA. this species, and in only three specimens have I found what might be considered to be a perfora- tion at the apex of the shell. In one of these it was clearly a circular fracture of the shell, and in the other two the apex had been pushed in so as to form a small circular depression with sharp edges. Several interiors of the shell also fail to show any indication of an opening through the shell; the specimen illustrated b}' Pander [1861, PI. II, fig. 2b] and the enlargement (g) are very much like the specimen with the minute circular opening caused by fracture. There are several other specimens in which there is a slight depression just in advance of the beak, which indicates that the shell was very thin and slightly flexible at this point. I would not venture to suggest that this was an imperfect ventral valve were it not for the fact that I have such an abundant supply of material which is clearly to be referred to the form described by Pander. I would further state that it frequently occurs that the apex of the shell is slightly raised above the surface so as to form a minute node and that when the apex is pushed in the edge of the depression follows a concentric line of growth. If we consider that Helmersenia is not a perforate shell, it then falls in with Obolus except that the area of the ventral valve is unlike that of Obolus and it has a spinose outer surface. The area, as illustrated by Pander [PI. LXIII, fig. 7d], is of the Mickvntzia monilifera type (PI. VI, fig. 1"). The shells of Helmersenia are delicate and much more like those of Mickwitzia than Oholus. The outer surface of MicJcivitzia is not known to be spinose, but if we compare the surface shown by figures 1 n and 2 (PL VI) with figures 7, 7a-b (PL LXIII) of Helmerseniawe gain an 'mpression of their great similarity. On account of the character of the area of the ventral valve, the appearance of the shell, and its surface, Helmersenia is placed within the Paterinidse. ' The generic name was given in honor of Gr^goire de Helmersen. Helmersenia ladogensis (Jeremejew). Plate LXIII, figures 7, 7a-f. Siphonotreta ladogensis Jeremejew, 1856, Verhandl. Russ.-kais. min. Gesell. St. Petersburg for 1855-6, No. 2, pp. 73 and 80, figs. 5a-c, p. 73. (Described in German on p. 80, as a new species.) Discina buchii Eichwald (in jjart) [not (db Verneuil)], 1860, Lethsea rossica, ancienne p&iode, vol. 1, sec. 2, p. 914. (Includes Siphonotreta ladogensis with Discina buchii.) Helmersenia Pander, 1861, Bull. Acad. imp. sci. St.-Petersbourg, vol. 3, columns 48^9, PL II, figs. 2a-g. (Described and discussed in German. Figs. 2d and 2f are copied in this monograph, PI. LXIII, figs. 7d and 7c, respectively.) Helmersenia jeremejewi Dall, 1877, Bull. U. S. Nat. Mus. No. 8, p. 31. (See the text below for discussion of this reference.) Keyserlingia panderi Karpinsky, 1887 (April), Bull. Acad. imp. sci. St.-P^tersbourg, vol. 31, p. 476, footnote. (Dis- cussed in German; see below.) Helmersenia jeremejewi Dall, Oehlert, 1887 (June), Manuel de conchyliologie, by Fischer, p. 1264. (Mentioned in French as type of genus; see below.) Helmersenia sp.? Pander, Hall and Clarke, 1892, Eleventh Ann. Rapt. State Geologist New York for 1891, p. 254, PI. IV, figs. 6 and 7. (Mentioned in the text, which is a description of the genus. Figs. 6 and 7 are copied from Pander, 1861, PL II, figs. 2d and 2b, respectively.) Helmersenia sp.? Pander, Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, p. 119, PL IV, figs. 4 and 5. (Mentioned. Figs. 4 and 5 are copied from Hall and Clarke, 1892a, PI. IV, figs. 6 and 7, respec- tively.) The specific description of this species has been included in the generic description. Pander [1861, p. 48] gave no specific name to the form which he described as Helmersenia, but he refers to Siphonotreta ladogensis Jeremejew in such a manner as to indicate that he con- sidered that species as the type. In 1877 Dall published a list of the names applied to the subdivisions of the Brachiopoda, and [1877, p. 31] designated the type species as Helmersenia jeremejem, ascribing the species to Pander and referring to page 47 of Pander's paper. Pander [1861, p. 48] places the words " SipJionotreta Jereraeiew" aiter Helmersenia, refers to the place of publication of Siphonotreta? ladogensis Jeremejew, and discusses the generic relations of the specimens before him with Siphonotreta ladogensis. It is thus evident that Pander did not name the species H. jeremejewi. CURTICIID^. 369 Dall tells me that he did not see Jeremejew's paper in which the specific name ladogensis was proposed. Ten years later Karpinsky [1887, p. 476], in his report on the Geology of the Government of Pskow, gives a list of the species occurring in the Ungulite sandstone and places a footnote after the word Helmersenia, in which he refers to " Keyserlingia" and suggests that the species be called "Keyserlingia panderi." In this footnote he mentions "Keyserlingia" three times, but places after the first a reference to Pander's description of Helmersenia. It is evident that Karpinsky intended to specifically identify panderi with Helmersenia and not Keyserlingia. A few months after the appearance of Karpinsky's paper Oehlert, in Fischer's Manuel de Conchyliologie, describes the genus Helmersenia [1887, p. 1264] and gives as the type H. jeremejevn Pander. He gives no reference, but it is likelj'' that he followed Dall. This form owes its specific name to its occurrence near Ladoga, near St. Petersburg, Russia. Formation and locautt. — Upper Cambrian: (336o) Ungulite grit, Koporje, Government of St. Petersburg; (336p) Ungulite grit, Kunitz, Government of Pskow; and (336q [Jeremejew, 1856, pp. 73 and 80]} Ungulite sandstone, near Ladoga, Government of St. Petersburg; all in Russia. Superfamily OBOLACEA Schuchert. Family CURTICIID^E Walcott and Schucliert. Genus CUBTICIA Walcott. Curtieia Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 319. (Mentioned aa below as a new genus.) Curticia Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 4, PI. XI, and pp. 142 and 143. (Classification of genus.) The description of the type species, Curticia elegantula, includes all that is known of this genus. The generic name is given in recognition of the excellent work of Dr. Cooper Curtice, of Moravia, New York, both as a field collector and laboratory assistant. Curticia elegantula Walcott. Plate I, figures 2, 2a-l. Curtida elegantula Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 319-320. (Described and discussed as below as a new species.) General form subcircular, biconvex. Surface of exterior of shell marked by fine, concentric, slightly undulating striae, and lines and varices of growth. When the thin exterior layer is exfoliated, the inner layers are ornamented by numerous fine, radiating lines, very much as in Dicellomus and Obolus, also by more or less imbricating concentric lines. The inner surface shows radiating and concentric lines without the visceral area. Shell substance corneous and probably calcareous. The shell is built up of a tliin, outer, surface layer and several inner layers or lamella, slightly oblique to the outer surface on the umbo and central parts of the valves. The lamellas are more oblique and numerous toward the front and sides, and thus thicken the shell over those parts. The average ventral valve Has a length of 5 mm.; width, 6 mm. ; dorsal valve, 5 mm. by 5 mm. Ventral valve strongly convex, most elevated at the umbo, and arching over to a minute, slightly incurved apex; area rudimentary, with a high, triangular, open delthyrium occupying most of it. A cast of the interior of the valve shows that a narrow, elevated ridge occurs just in advance of the apex, and a very small visceral area is indicated. Dorsal valve evenly convex, apex marginal; cardinal area rudimentary, narrow, and divided by a low, broad, open delthyrium. The interior shows a median ridge and septum, with small rounded depressions beneath the umbo on each side of the median ridge and a little in advance of the apex. Ventral muscle scars small and clearly defined. Anterior lateral scars small and situated in advance of the central scars close to the median ridge and at its anterior extremity. Main vascular sinuses broad and slightly defined. Ohservations. — This shell was labeled by the field collector as Dicellomus politus. In external form it resembles that species, but the open delthyrium of the ventral valve and the 62667°— VOL 51, pt 1—12 24 370 CAMBRIAN BRACHIOPODA. absence of an area on the dorsal valve distinguish it. It appears to be a forni intermediate in development between Rustella, with its absence of cardinal areas and its very rudimentary pedicle aperture, and Oholus, with its well-defined cardinal areas with their pedicle grooves. It occurs in large numbers and its dark smooth shell is a very striking object in the buff-gray sandstone. Formation and locality. — ^Upper Cambrian : (82b) " St. Croix sandstone " along the railroad track near Taylors Falls, Chisago County, Minnesota. Family OBOLID^ King. Subfamily OBOLIN^ DaU. Genus OBOLtTS Eichwald.a [i^Mc, a coin.l Oholus EiCHWALD, 1829, Zoologia specialis, vol. 1, p. 274. (Described in Latin as a new genus.) Unguliten Pander, 1830, Beitrage zur Geognosie des russischen Reiches, pp. 55-58. (Described and discussed in German.) Ungula Pander, 1830, idem, pp. 57-58. (Proposed as a new genus on p. 57 and described in German.) Ungulites Quenstedt, 1837, Archiv fur Naturgeschichte, von A. F. A. Wiegmann, Jahrg. 3, Bd. 1, pp. 143-145. (Refers to Pander's new genus Ungula as " Ungulites" and describes the genus in German.) Orthis VON Buch (in part), 1841, Archiv ftlr Mineralogie, Bd. 15, Hft. 1, p. 7. (Merely describes and discusses Obolv^ apollinis as "Orthis ungula," and refers the species to the " Unguliten, " the text being in German.) Unguliten Pander, von Buch, 1841, idem, p. 7. (The description of this group is incorporated with that of the species "Orthis ungula" {Oholus apollinis), the text being in German.) Oholus Eichwald, db Verneuil, 1845, G^ologie de la Russie d'Europe, by Murchison, de Verneuil, and de Keyserling, vol. 2, pt. 3, p. 291. (The genus is discussed in French in the third and fourth paragraphs on p. 291, under Oholus apollinis; see Matthew, 1892, pp. 43-44, for translation.) Oholus Eichwald, Kutorga, 1848, Verhandl. Russ.-kais. min. Gesell. St. Petersburg for 1847, No. 12, pp. 250-253. (Discussed in German.) Aulonotreta Kutorga (in part), 1848, idem, pp. 278-279. (Described in German as a new genus, the species in the genus belonging with Oholus, Oholus (Acritis), and Oholus (Miclcwitzella). Oholus Eichwald, Morris, 1849, Annals and Mag. Nat. Hist., 2d ser., vol. 4, pp. 319-320. (Discussed.) Oholus Eichwald, Davidson (in part), 1853, British Fossil Brachiopoda, vol. 1, introduction. No. 3, pp. 135-136. (Described and discussed. The species referred to the genus belong with Oholus, Oholus (Acritis), and Oholus (Mickwitzella). Two of the species, Oholus davidsoni and Oholus transversa, are Ordovician forms and are not taken up in this monograph.) o The synonymy for this genus does not give a complete record of the various genera under which the species now included in Obolus were formerly placed; it gives only those references in which the genus is discussed or described. To complete the record for the species taken up in the monograph the following mere generic references are listed: Oiolus von Leuchtenberg [1843, p. 16]. OtMcuU Owen [1852, p. 583]. Lingula Billings [1859, p. 431]. Oiolus Schmidt [1861, p. 218]. Lingula Billings [1863, p. 124]. Lingulepis HaU [1863, pp. 129 and 130]. Lingula Billings [1865a, p. 216]. Obolus? Billings (1866b, p. 362]. Lingulepis Hall [1867, p. 107]. Lingula Barrande [1868a, p. 100]. Obolus? Barrande [186Sa, pp. 104 and 105]. Lingula Barrande [1868b, p. 690], Obolus? Barrande [1868b, p. 693]. Linguldla? Meek [1871, p. 185]. Oholus Billings [1872a, p. 218; 1872c, p. 356]. Obolus Kayser [1876, p. 9]. Obolus Roemer [1876, PI. II, figs. 7a-c]. OboUlU Hall and Whitfield [1877, p. 205]. Lingulepis HaU and Whitfield [1877, p. 206]. Lingula Barrande [1879b, Pis. CVI: iv; CX: vin; CXI: I, and CXI: VI]. Obolus? Barrande [1879b, Pis. XCV: iv; CXI: vi; GXIII: v; CXXVI:n; and CLII: iij. Obolus Noetllng [1883, p. 265]. Lingulella Kayser [1883, p. 35]. Lingulepis Waloott [1884b, p. 12). Obolella Walcott [1884b, p. 14). Obolus Roemer [1885, p. 23 (270)]. Obolella? Walcott [1886b, p. 111). Lingulella Walcott [1889c, p. 441). Obolus Gagel [1890, p. 21). Lingula Bomeraann [1891, p. 438). Obolella Bornemann [1891, pp. 439 and 440). Lingulella? Hall and Clarke [1892c, p. 61]. Obolella?? Hall and Clarke [1892c, pp. 69 and 73). Lingulella Keyes [1894, p. 38). Lingulella Matthew [1895b, p. 255). Lingula Sardeson [1896, p. 95). Schmidtia Mickwitz [1896, p. 19]. Olossina Schuchert [1897, p. 224). Lingulella? Walcott [1897a, p. 404). Obolus (.Lingulella) Walcott [1898b, pp. 404, 412, 415, 410, 418, and 419; 1899, pp. 443 and 445; 1901, p. 673). Obolus Walcott [1901, p. 684). Obolus Matthew [1902c, pp. 94 and 96). Obolus (MonoboUna) Matthew [1902e, p. 98). Lingulella Matthew |1902c, p. 108). Obolus (Lingulella) Walcott [1902, p. 605). Lingulella Matthew [1903, p. 62). Obolus Matthew [1903, p. 76). MonoboUna Matthew [1903, p. 210). Obolus Walcott [1905a, pp. 324, 325, 326, 327, and 328j. Obolus (.Lingulella) Waloott [1905a, pp. 328, 330 , and 331). Obolus Moberg and Segerberg [1900, p. 65) Obolus Walcott [190Sc, p. 244; 1908d, pp. 61, 02, and 63). OBOLIDiE. 371 Obolus EicHWALD (in part), 1860, Letheea rossica, ancienne p&iode, vol.l, sec. 2, pp. 924-925. (Described in French. The species referred to the genus belong with Obolus, Obolus (Acritis), and Obolus (Mickwitzella).) Obolus Eichwald, Davidson, 1866, British Fossil Brachiopoda, vol. 3, pt. 7, No. 1, p. 58. (Gives synonymy and refers genus to Lingulidse.) Not Schmidtia von Volborth, 1869, Verhandl. Russ.-kais. min. Gesell. St. Petersburg, 2d ser., pt. 4, pp. 208-209. (Characterized and discussed as a new genus to include those forms which had been referred to Ungula, but which were not included in Ungulites Quenstedt, 1837, p. 143. Schmidtia celatus is, however, described as the only representative of the new genus.) Obolus Eichwald, Dall, 1870, Am. Jour. Conchology, 2d ser., vol. 6, pt. 2, pp. 154 and 162. (Described.) Ungula Pander, Dall, 1877, Bull. U. S. Nat. Mus. No. 8, p. 75. (Discusses date of publication of Ungula Pander, Ungula Rose, and Obolus Eichwald.) Obolus Eichwald, Zittel, 1880, Handbuch der Palaeontologie, Bd. 1, Abth. 1, p. 664. (Described in German.) Obolus Eichwald, Davidson, 1883, British Fossil Brachiopoda, vol. 5, pt. 2, p. 218. (Mentioned in discussion of Siphonotrela.) Ungulites Quenstedt, 1885, Handbuch der Petrefactenkunde, Aufi. 3, p. 756. (Characterized in German.) Obolus Eichwald, Oehlert, 1887, Manuel de conchyliologie, by Fischer, p. 1261. (Described in French, with figures of " 0. davidsoni Salter" and " 0. politus Kutorga.") Obolus MicKwiTz, 1892, Melanges geol. et paleontol. tires du Bull. Acad, imp, sci. St.-P6tersbourg, vol. 1, pp. 57-64. (Described and discussed in German.) Obohu Matthew, 1892, Trans. Roy. Soc. Canada, 1st ser., vol. 9, sec. 4, No. 5, pp. 43-44. (Translates the descrip- tion given by de Verneuil, 1845, p. 290.) Obolus Eichwald, Hall and Clarke, 1892, Eleventh Ann. Rept. State Geologist New York for 1891, pp. 242-243. (Described and discussed.) Aulonotrcta Kutorga, Hall and Clarke (in part), 1892, idem, pp. 243-244. (Described and discussed. As discussed the genus includes species referred to both Obolus and Obolus (Acritis).) Obolus Eichwald, Hall and Clarke, 1892, Forty-fifth Ann. Rept. New York State Museum, for 1891, pp. 558-559. (Copied from Hall and Clarke, 1892a, pp. 242-243.) Aulonotreta Kutorga, Hall and Clarke (in part), 1892, idem, pp. 559-560. (Copied from Hall and Clarke, 1892a, pp. 243-244.) Obolus Eichwald, Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, pp. 80-81. (Described and discussed.) Aulonotreta Kutorga, Hall and Clarke (in part), 1892, idem, p. 82. (Described and priority of generic references, ^-tc, discussed. As discussed the genus includes species referred t« both Obolus and Obolus (Acritis).) Obolus Eichwald, Hall and Clarke, 1892, idem, pp. 337-339. (Gives a translation of Mickwitz's diagnosis, 1892, and discusses genus.) Obolus Eichwald, Mickwitz, 1896, M6m. Acad. imp. sci. St.-P^tersbourg, 8th ser., vol. 4, No. 2, pp. 1-133. (These pages contain a general discussion of the genus and its relations, in German, the actual diagnosis of the genus being given on pp. 127-129.) Obolus (Euobolus) Mickwitz, 1896, idem, pp. 129 and 133. (Characterized in German, on p. 129, as a new subgenus.) Obolus Eichwald, Walcott, 1898, Proc. U. S. Nat. Mus., vol. 21, pp. 385-386. (Genus and type species discussed.) Obolus Eichwald, Walcott, 1901, Proc. TJ. S. Nat. Mus., vol. 23, pp. 681-683. (Described and discussed, translating a portion of Mickwitz's description, 1896, pp. 118-121.) Obolus Eichwald, Matthew, 1903, Geol. Survey Canada, Rept. Cambrian Rocks Cape Breton, p. 135. (Characterized and discussed.) Obolus {Eoobolus) Matthew (in part), 1903, idem, pp. 135-136. (Characterized as a new subgenus. One of the three species referred to the subgenus belongs with Obolus and the remaining two belong with Lingulella.) Obolus Eichwald, Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 4, PI. XI, and pp. 142 and 144. (Classification of genus.) Diagnosis (mainly after Mickwitz [1896]). — Shells nearly equivalve, equal-sided, moder- ately convex, subcircular, transversely or longitudinally ovate, in some species subtriangular or subrectangular. Shell substance calcareocorneous, structure foliated ; the layers of calcium phosphate alter- nating with homogeneous, horny lamellae are traversed by microscopic canals, which in their main direction are perpendicular to the plane of stratification; the inner layers and lamellae are more or L-ss oblique to the thin outer layer over the central and posterior portions of the valves, and strongly so with the short lamellae of the anterior and lateral parts. Surface shining as if varnished, with concentric and usually radial striation, varying from bare visibility to deeply incised concentric folds and radial ribs. Color of shell dark grayish blue to black, when in a state of decomposition dark reddish brown to whitish. Front and side margins usually thin, sharp-edged, fragile, lying in the same plane with the hinge margin, which is greatly thickened inside. Area mainly in the plane of the edge of the valve, in the ventral valve triangular, owing to the somewhat projecting beak, in the dorsal valve rounded at the point, 372 CMIBRIAN BRACHIOPODA. in both striated parallel to the base, and trayersed, from the point of the beak on, by the more or less diverging lines of folding of the areal lamellae and a strongly marked pedicle furrow. Visceral area (splanchnoccEle) on the ventral valve restricted to the back part, in the dorsal valve drawn far forward into the vascular area (brachiocoele) and strongly indented laterally ; in both valves it extends backward up close to the base of the visceral (splanchnocoelic) part of the area, which is bounded by the flexure line (folding of the area lamellae). The edge of the mantle of the beak part is restricted to the side areas (pleurocoeles), appearing between the flexure lines of the area lamellae. Anterior part of the thickened posterior half of valve slopes down to the middle of the valve, forming in the ventral valve a line concave to the beak, in the dorsal valve a sinus. The lateral parts of the thickening are drawn out into thin side edges. In front of the base of the area is a small median septum, which in the dorsal valve for the most part is less prominent, but in both is often hardly perceptible by reflected light as an almost invisible crest. Beginning at the median septum, there are in each valve two gradually deepening grooves for the main vascular canals, which intersect the thickened part parallel to the edge of the shell. In the dorsal valve these grooves combine with the sinus from the calcareous ridge in forming two projections pushing themselves like horns into the middle of the valve. The traces of the main vessels of the mantle lobes in the continuation of the visceral (splanchnocoelic) vascular grooves are subparallel and project into the vascular (brachiocoelic) parts of the valves, in the ventral valve terminating with their anterior ends in the peripheral vascular canal, in the dorsal valve, shortly before reaching the vascular canal, bending about into the interior of the shell, and vanishing at the scars of the anterior lateral muscles. The peripheral vascular canals in both valves run along their edge from one side area (pleurocoele) to the other. Traces of secondary vessels radiate in great number from the grooves of the main vessels toward the peripheral canals and into the middle of the shell. In the median line of the ventral valve, between the median septum and the anterior edge of the thickened part of the shell, there is a deep, heart-shaped pit, with its point directed forward and having a shallow median groove. In the cavity of the dorsal valve there is a more or less pronounced median ridge, extending into the anterior part of the valve and divided longitudinally by a shallow median furrow. On each valve there are six pairs of muscular scars, and in the ventral valve in front of the pedicle furrow there is the unpaired scar of the pedicle muscle. The umbonal scars are close to the base of the area, in the ventral valve divided, inclosing the scar of the pedicle muscle between them, in the dorsal valve confluent in the median line of the valve. The scars of the central pair of muscles are placed about centrally in both valves; in the dorsal one they are isolated on the inner sides of the ends of the hornlike projections; in the ventral valve they are united with the scars of the outside and middle lateral muscles, on both sides of the anterior part of the heart-shaped pit. The transmedian muscles are undivided; their scars in both valves are close to the base of the area in the line of prolongation of the flexure lines. The anterior lateral muscle scars of the ventral valve adjoin the transmedians, overlapping tliem a httle on the outside; in the dorsal valve they are isolated, pushed far forward toward the frontal margin and situated at the anterior end of the median crest separating them. The scars of the second pair, the middle lateral muscles, in the ventral valve are combined with those of the central and outside lateral muscles at the point of the heart-shaped pit; in the dorsal valve they blend with those of the outside lateral muscles and lie against them on the inner sides of their anterior ends. Finally the scars of the third pair, the outside lateral muscles, in the ventral valve are combined with those of the central and middle lateral muscles and lie on the outer sides of the former, while in the dorsal valve they are united with those of the middle lateral muscles and lie obliquely outward before the scars of the transmedian muscles. In both valves the parietal band closely circumscribes all muscle scars externally, crossing the furrows of the main vessels and entering the visceral (splanchnocoelic) part of the area at its base on a line with the flexure lines. The study of a series of the interior of the ventral valve of Oholus apollinis (PI. VII) shows that the arrangement of the point of attachment of the middle (k) and outside (1) laterals and OBOLIDiE. 373 central muscle scars (h) varies considerably in the different specimens, Mickwitz's diagram- matic figure shows the middle lateral scars (k) to be the smaller and situated close to the median line. This, however, is not the case in all specimens. In Plate VII, figure 9, the middle lateral (k) is the larger and the two other scars are arranged quite differently from those in Mickwitz's diagrammatic figure. In Plate VII, figure 5, the growth of the shell has crowded all three of the muscle scars so that they are arranged in transverse lines. In Plate VII, figure 4, they occur up on the side of the visceral cavity (v), the central scars (h) occupying the greater portion of the space, the outside laterals (1) being crowded forward, and the middle laterals (j), which are so large in figure 9, are scarcely to be determined at the inner angle in figure 4. In Plate VII, figure 3, the jjoints of attachment of the scars are on a ridge, and they present no points of similarity to the position assigned in the diagrammatic figure of Mickwitz, nor to the positions in Plate VII, figures 9, 4, and 5. The points of attachment are sunk deep into the ridge, and on this account it is impracticable to distinguish between the central (h) and middle lateral (k) scars. In figure 1 the scars are also on a high ridge. They are slightly depressed and apparently range very much as in Plate VII, figure 5, except that the middle laterals (k) are nearer the median line. It does not appear to be possible to distinguish the centrals. Type. — 0. apoUinis Eichwald. Observations. — It is stated by Hall and Clarke [1892c, p. 339] that Mickwitz did not obtain his results from the type specimens of Oholus apoUinis, but from a hitherto undescribed form, Oholus quenstedti. Tins is true [see Mickwitz, 1890, p. 60, footnote], but in liis final work [1896, p. 128] Mickwitz diagnoses the genus and cites Oiolus apoUinis as the type. He says [1896, p. 25]: A more accurate study of the greatly increased material has convinced me that 0. quenstedti can not be maintained as a species, since it is merely the terminal link of a series of variations which, like var. maximus and ingriais, can be traced back to 0. apoUinis. Thus, the typical species remains 0. apoUinis Eichwald. Mickwitz [1896] has given in his exhaustive memoir on Oholus a very complete historical sketch and full description of the genus and its subgenera so far as known to him. The study was conducted with such care and thoroughness and the material was so well preserved that our present knowledge of the adult shell of Oiolus is nearly as complete as that of the adult shell of the recent Lingula. The student is referred to the memoir of Mickwitz for the literature, history, and geology of the Cambrian formations of the eastern Baltic region of Russia, for a minute description of the external and internal characters of the shells of the Baltic species of Oholus and of the relations of Oholus to Lingula and Oholella, and for detailed observations on Oholus and its subgenera as known to him. Oholus and Lingula. — After studying the species from American rocks and a very good series from the typical localities in Russia, I am not prepared to agree with Mickwitz that Oholus should be referred to the Lingulidas. In figure 34 the interior of the valves of Oholus and Lingula may be compared. Figure 34.— Interiors of valves of Obolus and Lingula. Obolus apolUnis quenstedti Mickwitz. After Mickwitz [1896, figs. Oa-b, p. 79]. A, Ventral valve; B, dorsal valve. I. Splancimoccele. II. Brachiocoele. III. Pleiiroccele. a. Pedicle furrow. b. Parietal band. The synonymy for this subgenus does not give a complete record of the various genera under which the species now included in Mickwitzella were formerly placed; it gives only those references in which the genus is discussed or described. To complete the record the following mera generic references are listed: Obolus Eichwald [1843, p. 7). Obolm de Vemeuil [1845, p. 290]. Obolus Eichwald [1859, PI. XXXVII, flgs. 6 and 7). Obolus Schmidt [1801, p. 218; 1881, p. 17]. Lingula Schmidt [1881, p. 17]. Obolus Mickwitz [1892, p. 60]. OBOLID^. 435 Obolus apoUinis Eichwald, de Vernbtjil (in part), 1845, G^ologie de la Russie d'Eui-ope, by MimchisQn, de Vemeuil, and de Keyserling, vol. 2, pt. 3, pp. 290-292. (Described and discussed in French. The reference includes Obolus {ilichwitzella) siluricus, Obolus (Acritis) antiquissimus, Obolus apollinis, and Obolus apolUnis ingricus; Obolus apollinis being figured.) Aulonotreta polita Kutorg.\ (in part), 1848, Verhandl. Russ.-kais. min. Gesell. St. Petersbm-g for 1847, No. 12, pp. 279-282 (not PI. VII, figs. lOa-f). (Described and discussed in German as a new species. The text includes Obolus {ilickwitzella) siluricus, Obolus apollinis ingricus, and Obolus apollinis, the last species being figured.) Obolus siluricus Eichw.-vld, 1859, Lethsea rossica, ancienue periode, Atlas, PL XXXVII, figs. 6 and 7a-b. (The text reference accompanying these figm-es is in the following citation.) Obolus siluricus Eichwald, 1860, Lethaea rossica, ancienne periode, vol. 1, sec. 2, pp. 927-928. (Described and dis- cussed in French.) Obolus siluricus Eichwald, Schmidt, 1861, Ai-chiv fiir Naturkunde Liv-, Ehst-, und Kuidands, 1st ser., vol. 2, p. 218. (Mentioned in German.) Obolus siluricus Eichwald, Schmidt, 1881, Mem. Acad. Imp. Sci. St.-P^tersboui-g, 7th ser., vol. 30, No. 1, p. 17. (Local- ity mentioned in German.) Lingula cf. davisi Salter, Schmidt, 1881, idem, fig. 5, p. 17. (Mentioned in the text.) Obolus siluriais Eichwald, Mickwitz, 1892, Melanges g^ol. et paleontol. tii-es du Bull. Acad. imp. sci. St.-P6tersboiirg, vol. 1, p. 60. (Mentioned in German.) Obolus (Thysanotos) siluricus (Eichwald), Mick-witz, 1896, Mem. Acad. imp. sci. St.-P^tersbourg, 8th ser., vol. 4, No. 2, pp. 195-199, PL III, figs. 1-9. (Described and discussed in German; see below for translation. Fig. 9 is copied in this monograph, PL XV, fig. lb.) Mickwitz [1896, pp. 195-199] describes the species as follows: Shells large, very flatly arched, thin, brittle. Outline of shells round, somewhat broadened. Posterior borders of shells rectilinear, not winged. Tip of the beak of large shell slightly curved inwardly. Sui-face of shell very lustrous, like varnish. Concentric strife in sharp-edged ribs, which are separated by flat troughs. These ribs run parallel to the posterior borders of the growth lamellae and therefore always become shorter toward the anterior borders of the same. Growth lamellse prettily fringed at the anterior borders; the concentric striae are continued on the fringes. Area large, quite smoothly striate, slightly excavated at the base of the splanchnoccelic part. Pleiuoc'oelic part of the area extends far into the lateral borders of the shell. Traces of the pseudo-area lamellae approach the borders of the peduncular gi-oove, and converge into the tip of the beak. Peduncular gi-oove large, deep, roundly hollowed, inwardly strongly broadened. Thickening of the shells veiy slight. Central groove of the large shell indefinitely flat. Corneous processes and sinus of the small shell strongly receding. Median swelling of the small shell broad and flat, divided at its anterior half by a broad median gi'oove. Principal vascular traces broad and flat, separated by a median swelling into two sharp-cut fm-rows. Places of attachment of the central muscles of the small shell large, cu-cular; those of the umbonal muscles very coarsely longitudinally striate. Obsei-vations: The large shell of this species reminds one in form of 0. apollinis quenstcdti, especially of a specimen whose relative numbers also somewhat coiTespond with those of 0. siluricus. In comparing these numbers, one must take into consideration that the only large shell of the last-mentioned species, which allowed measm-ement, is some- what pressed in from above, so that the heights given in the table of measures may most hkely be somewhat too small. The small shell, however, has a somewhat broader form than the con-esponding Cambrian species, and varies in outline by ha^dng the gi-eatest breadth nearer the anterior border. The exterior surface of the shell of 0. siluricus has aheady been spoken of on several occasions: The crescent -shaped growth lamelte, which coiTespond to a vegetative period, run out as in all Obolus shells into the posterior borders of the shell, which, so to say, inclose them. The law of gi-owth of the gi-owt.h lamellte, or the seam of the mantle which produces the same, is plainly here and there the same. Now the aberrancy of this species consists in the fact that the concentric striae of these lamellae do not converge into the tip of the crescent as the other species — with the exception of 0, antiquissimus — but run parallel to the posterior (interior) border of the lamellae and therefore always become shorter toward the anterior. It is self-evident that this aberrant plaited formation must have corresponded to an aberrant character of the seam of the mantle, but what the character of the latter was is unknown. Also the profile of the con- centric striation of 0. siluricus deviates essentially from the other ornamented species of EichwaM's genus; for example, 0, triangularis shows a regular wavy line in which the crests and troughs of the wave are composed of equal cm'ves. In 0. siluricus, however, the cm'ves of the troughs follow immediately on one another, so that the crests run out into sharp points, 0, antiquissimus, which has an intermediate form, shows the crests of the waves somewhat rounded off at the point. The fringes, with which the growth lamellae are ornamented at the close of the vegetative period, correspond with the radial striation on the interior side of the appertaining lamellae in such a manner that every notch between two teeth of fringes is equal to a radial fmTOW, These radial f iutows, which owe their formation to the setae, which are sunk into the seam of the mantle, are peculiar to all Oboli and were aheady observed in the impression by Eichwald in all shells whose upper layer (gi'owth lamella) was broken off. To every notch of the fringe therefore corresponds a seta of the mantle. The subject can not be followed any fm-ther. We also here meet with the peculiar but unknown charac- ter of the seam of the mantle, which produces a pretty fringe in the vegetative rest; in the period of gi-owth, however, it produces a lamella which is interrupted at the border, both being f m-nished with concentric ribs. The teeth of the 436 CAMBRIAN BRACHIOPODA. fringes, at the antorior border of the adult shell, reach a considerable length (four to five transverse ribs); near the beak they are only indicated. The breadth of the growth lamellre of this species varies greatly. One shows in the center of the shell a width of 5.5 mm., while the center lamella of another is only 2 mm. broad. This is plainly connected with the relative condi- tions of nourishment. Independent thereof also here, as with all Oboliis species, a diminishing of the breadth of the lamellfe toward the anterior border of the adult shell takes place. The shells of 0. siluricus are very thin, and consequently the development of the inner characters is very slightly pronounced. In striking contrast to this peculiarity stands the strongly developed area with the broad, deeply hollowed peduncular groove, which somewhat diminishes toward the beak. The surface of the area is smooth at the posterior part, and gives rise to the conjecture that in consequence of a narrow closing of the shell a mutual attrition has taken place. (Similarly as in 0. antiquissivivs, only in a less degree.) The same conclusion is forced upon one by the deeply hollowed peduncular gi-oove, which allowed, even with the narrow closing of the shell, sufficient space for the passing of the peduncle; and lastly, the strongly developed longitudi- nally striate places of attachment of the umbonal muscle. A small shell of a young specimen also shows this place of attachment distinctly but lacks the striation in the figure. The beak of the small shell also has in its youth a rectilinear bordered tip. In age this is somewhat worn off, so that the beak has a round appearance. The area of the small shell is hollowed transversely to the median line and therefore not exposed to attrition, which is limited to the borders of this shell. Unfortunately this part is only at hand in the ah-eady mentioned young specimen. The inner characters of 0. siluricus are more withdrawn from observation. On the one hand they are, as aheady mentioned, very slightly developed; on the other hand sufficient material is lacking. The central groove of the large shell is very flat and indefinitely bordered, but is perceptible in both figured specimens. The principal vascular fmTows are more distinctly distinguishable, their central swellings are strongly developed and rear themselves from the deeply hollowed lateral fiurows. In one specimen the secondary vascular traces may be followed under a magnifying glass. The accessory vessels, radiating inwardly and perpendicularly to the principal vessels, run rectilinearly to the anterior border, and bend off shortly before reaching the median line, as has been demonstrated in other species. A shortly branched ramification of the first part of these vessels was only suggestively perceptible. The outwardly directed accessory vessels run in the known manner. Their opening into the peripheral canal is not perceptible on account of corrosion of this part of the shell. Of the remaining visible characters in the figured large shell only the places of attachment of the combined central muscles are to be mentioned, which, however, can not be analyzed into their elements on account of the deficient pre- servation of the shell. In their totality, they form a narrow band, which lies before the central groove and is bordered by the parietal band. This band curves, close to the inner lateral fm-rows of the principal vessels, rectangularly toward the back and is widened there considerably. This portion, however, is corroded, so that the exact form of the place of attachment can not be ascertained. In the small shell, apart from the already mentioned place of attachment of the umbonal muscle, the large chcular places of attachment of the central muscles may be seen for the first time, and lie near the center of the fragment of the shell on both sides of the flat median swelling, which is divided by a broad median fmrow. The places of attachment of the anterior lateral muscles are also perceptible, but only suggestively. They ah-eady lie in the scaled-off part of the anterior half of the shell. On the left above, the elongate, quite deeply sunk place of attachment of the transmedian muscle is also perceptible. Lastly, the beginnings of the principal vascular traces and parietal band, as far as the inner smiace of the shell is intact, may be followed and are also expressed in the figure. The species owes its specific name to the "Sihirian" age of the beds in which it is found. Formation and locality.'^: — Passage beds between the Upper Cambrian and the Ordo-idcian: "Glauconite sandstone" at the following localities: (396) At Baltischport, 30 miles (48 km.) west of Reval; (396a) at Leppilco, near Leetz, on the eastern side of the Baltischport Peninsula, about 25 miles (40.3 km.) ivest of Reval; (396b) at Fall, 15 miles (24 km.) west of Reval; (396o) at the mouth of Fahna Brook, east of Fall, about 15 miles (24 km.) west of Reval; and (396e) in the eastern part of the east Baltic region; all [Mickwitz, 1896, p. 198] in the Government of Esthonia, Russia. (395x [Lamansky, 1901, p. 617]) Glauconitic sandstone (correlated by Lamansky with the Upper Cambrian Cera- topyge slate) in the vicinity of Baltischport, 30 miles (48 km.) west of Reval; (395v [Eichwald, 1843, p. 147]) sandstone on Odensholm Island, about 55 miles (88.6 km.) west of Reval; (396y [Eichwald, 1843, p. 147]) chlorite-bearing sands in the limestone beds at Reval; (336f [Eichwald, 1860, p. 927]) pjTOxene-bearing sands in the Orthoceratite limestone beds at Reval; (3371 [Schmidt, 1861, p. 218]) green sand at Baltischport; and (396x [Eichwald, 1843, p. 146]) chlorite- bearing sands in the limestone beds at Baltischport, about 30 miles (48 km.) west of Reval; all in the Government of Esthonia, Russia. (395w [Eichwald, 1843, p. 147]) Chlorite-bearing sands in the limestone beds at Pawlowsk; and (395y [Kutorga, 1848, p. 281]) sandstone on Pulkowa Brook; both near St. Petersburg, Russia. (368a [Siemu-adzki, 1886, p. 672]) Gray sandstone of unknown stratigi-aphic position or age, in the Polnischen Mittelgebirge, north of Sandomierz on the Vistula, Russian Poland. a Localities 396 and 396a are represented in the collections of the United States National Museum. OBOLIDiE. 437 ACBITIS VolborthjO subgenus of OBOLTTS. [oKflcToc, indiscernible.] Aulonoireia Kutoroa (in part), 1848, Verhandl. Russ.-kais. min. Gesell. St. Petersburg for 1847, No. 12, pp. 278-279. (Described and discussed in German as a new genus. The species referred to the genus belong with Obolus, Obolus (Acritis), and Obolus {Mkhvntzella).) Aulonotreta Kutorga, Morris, 1849, Annals and Mag. Nat. Hist., 2d ser., vol. 4, pp. 316-317. (Characterized and discussed as a synonym of Obolus.) Obolus Eichwald, Davidson (in part), 1853, British Fossil Brachiopoda, vol. 1, introduction, No. 3, pp. 135-136. (Described and discussed. As far as they have been identified in this monograph the species referred to the genus belong with Obolus, Obolus (Acritis), and Obolus { Midcwitzella) .) Obolus Eichwald (in part), 1860, Lethsea rossica, ancienne p^riode, vol. 1, sec. 2, pp. 924-925. (Described in French. The species referred to the genus belong with Obolus, Obolus (Acritis), and Obolus ( Michwitzella) .) Acritis VoLBORTH, 1869, Verhandl. Russ.-kais. min. Gesell. St. Petersburg, 2d ser., Bd. 4, pp. 212-217. (The descrip- tion and discussion of the genus (in German) is incorporated with that of Obolus (Acritis) antiquissimus.) Acritis Volborth, Dall, 1877, Bull. U. S. Nat. Mus. No. 8, p. 11. (Placed as a synonym of Aulonotreta.) Aulonotreta Kutorga, Dall, 1877, idem, p. 16. (Priority of this generic name over, 4cnh's discussed.) Acritis Volborth, Oehlert, 1887, Manuel de conchyliologie, by Fischer, p. 1264. (Described in French.) Aulonotreta Kutorga, Hall and Clarke (in part), 1892, Eleventh Ann. Bept. State Geologist New York for 1891, pp. 243-244. (Described and discussed. As discussed the genus includes species referred to both Obolus and Obolus (Acritis) .) Aulonotreta Kutorga, Hall and Clarke (in part), 1892, Forty-fifth Ann. Kept. New York State Museum for 1891, pp. 559-560. (Copj' of preceding reference.) Aulonotreta Kutorga, Hall and Clarke (in part), 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, p. 82. (De- scribed and discussed and priority, etc., of generic references discussed. As discussed, the genus includes species referred to both Obolus and Obolus (Acritis).) Obolus (Acritis) (Volborth), Mickwitz, 1896, M6m. Acad. imp. sci. St.-P6tersbourg, 8th ser., vol. 4, No. 2, pp. 205-206. (Characterized and discussed in German as a subgenus; see -below for translation.) Obolus (Acritis) (Volborth), Walcott, 1901, Proc. U. S. Nat. Mus., vol. 23, p. 683. (Characterized.) Obnlus (Acritis) Volborth, Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 4, PI. XI, and pp. 142 and 144. (Classi- fication of subgenus.) Mickwitz describes the subgenus as follows: The subgenus Acritis, like the two preceding subgenera, Thysanotos (^ Michvitzella) and Leptembolon, is based on a single species, Obolus antiquissimus Eichwald, which, out of all the species of Eichwald's genus, departs most widely from the typical species. The most prominent characteristics of this subgenus — apart from the parallelism of the concentric striation of the surface of the shell, which it has in common with the subgenus Th/sanotos (^ Mickwitzella) — consist in the remarkable shortening of the splanchnocoele, which even in the adult stage of the animal advances but little toward the frontal edge, and in the different arrangement of the deposit of the thickened lamellse, which impart to the adult shells a totally different appearance. The failure to recognize these facts was the main cause of the long controversy over the genus of 0. antiquissimus, which after all threw no light on the subject. Type. — Obolus (Lucina) antiquissimus Eichwald [1843, p. 142]. . Obolus (Aceitis) antiquissimus (Eichwald). Plate XIII, figure 3; Plate XV, figures 2, 2a-d. Obolus (Lucina) antiquissimus Eichwald, 1843, Beitrage zur Kenntniss des russischen Reiches, Bd. 8, No. 2, pp. 142-144, PI. IV, figs. la-c. (Described and discussed in German as a new species.) Obolus apollinis Eichwald, de Verneuil (in part), 1845, G^ologie de la Russie d'Europe, by Murchison, de Verneuil, and de Keyserling, vol. 2, pt. 3, pp. 290-292. (Described and discussed in French. The reference includes Obolus (Michwitzella) siluricus, Obolus (Acritis) antiquissimus, Obolus apollinis, and Obolus apollinis ingricus, Obolus apollinis being figured.) Aulonotreta sculpta Kutorga, 1848, Verhandl. Russ.-kais. min. Gesell. St. Petersburg for 1847, No. 12, pp. 282-283 PI. VII, figs, lla-d. (Described and discussed in German as a new species.) Obolus apollinis Eichwald, Davidson (in part), 1853, British Fossil Brachiopoda, vol. 1, Introduction, No. 3, PL IX, fig. 285 (not figs. 280-284, which represent Obolus apollinis). (No text reference. Fig. 285 is copied from Kutorga's figure, 1848, PI. VII, fig. lib, of Aulonotreta sculpta.) a Tiie synonymy for this subgenus does not give a complete record of the various genera under which the species now included in .-1 critis were formerly placed; it gives only those references in which the genus is discussed or described. To complete the record, the following mere generic references are listed: Obolus (Lucina) Eichwald [1S43, p. 142]. Obolu.': de Verneuil [1845, p. 290]. Obolus Eichwald [1859, PI. XXXVII, figs. 5a-dJ. Obolus Siemiradzki[188G, p. 072]. Acritis Gagel[1890, p. 22]. Acritis Hall and Clarke [1892, p. 82). 438 CAIIBEIAN BEACHIOPODA. Obolus antiquissimus Eichwald, 1859, Lethasa rossica, ancienne p(5riode, Atlas, PI. XXXVII, figs. 5a-d. (The accompanying text is cited in the following reference.) Obolus antiquissimus Eichwald, 1860, Lethsea rossica, ancienne periode, vol. 1, sec. 2, pp. 928-929. (Described and discussed in French.) Acritis antiquissima Volborth, 1869, Verhandl. Russ.-kais. min. Gesell. St. Petersburg, 2d ser., Bd. 4, pp. 212-217, PI. XVII, figs. 7-9. (Described and discussed in German, the description of the genus Acritis being incor- porated with that of the species.) Aulonotreta sculpta Kutorga, Dall, 1877, Bull. U. S. Nat. Mas. No. 8, p. 16. (Discusses the priority of the generic names proposed for this form.) Obolus siluricus (Eichwald), Siemiradzki, 1886, Jahrb. K.-k. geol. Eeichsanstalt for 1886, Bd. 36, Hft. 4, p. 672. (Characterized and new locality mentioned.) Acritis antiquissima (Eichwald), Gagel, 1890, Beitr. zur Naturkunde Preussens, von Phj'sikal.-oekonom. Gesell. Konigsberg, 6, p. 22, PL I, fig. 1. (Described in German.) Aulonotreta antiquissima (Eichwald), Hall and Clarke, 1892, Eleventh Ann. Kept. State Geologist New York for 1891, figs. 246 and 247, p. 244. (No text reference. Figs. 246 and 247 are copied from Volborth, 1869, PL XVII, figs. 7 and 9, respectively.) Aulonotreta antiquissima (Eichwald), Hall and Clarke, 1892, Forty-fifth Ann. Rept. New York State Museum for 1891, figs. 246 and 247, p. 560. (No text reference. The figures are copied from the preceding reference.) Acritis antiquissima (Eichwald), Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, p. 82, figs. 35 and 36. (Species discussed, and priority, etc., of generic references discussed. Figs. 35 and 36 are copied from Volborth, 1869, PL XVII, figs. 7 and 9, respectively.) Obolus {Acritis) antiquissimus (Eichwald), Mickwitz, 1896, M6m. Acad. imp. sci. St.-P^tersbourg, 8th ser., vol. 4, No. 2, pp. 206-213, PL III, figs. 20-22, 24-29. (Described and discussed in German; see bellow for translation. Figs. 20a-b are copied in this monograph, PL XV, fig. 2d.) Obolus (Acritis) antiquissimus ventrosus Mickwitz, 1896, idem, pp. 213-214, PL III, figs. 23a-b. (Characterized in German as a new variety.) Mickwitz [1896, pp. 206-213] describes this species as follows: Shells large, strongly arched. Arching of the large shell slighter than that of the smaller. Greatest height of both shells more toward the beak. Outline of shell broadly oval to round, broader than long, the greatest width lying more to the anterior border. Beak of the large shell very blunt, laterally rounded ; extreme tip of the beak of the large shell lapping hook-shaped over the rectilinearly worn-off tip of the beak of the small shell. Growth lamellfe very thick, loosely disposed, their anterior sharp-edged borders projecting like a molding on theu- inner surfaces, strongly radially ribbed. Concentric striae of the outer sm-face of the shell in wavy roundish ribs, which run parallel to the posterior border of the crescent-shaped gi'owth lamellae, growing constantly shorter toward the anterior border of the same. Anterior and lateral borders sharp-edged, lying in one plane with the worn-off borders of the beak. Pos- terior borders of the shell massive, broad, projecting inwardly in shape of a border. Area of both shells strongly devel- oped, broadly ribbon-shaped, prolonged far into the lateral borders, deeply hollowed, polished on the surface by mutual attrition. Peduncular groove strongly conical, deeply sunk, inwardly often broadened like a trumpet, traces of the pseudo-area rectilinear, converging into the tip of the beak, attaining to distinctness as a line of the markation of the narrow splanchnocojlic and the broad pleuroccelic heads of the layers of the worn area lamellae. Thickening of the shell extended chiefly to the brachiocoele, advancing in scalariformed terraces which follow the contours of the parietal band; with the large shell forming a thick mass in front of the central gi'oove, and with the small filling out the lateral angular seams which penetrate into the splanchnocoele. Splanchnocoele small, crowded back strongly to the beak, reaching under the rimlike projecting posterior border of the shell. Heart-shaped groove very small, very indistinctly pronounced, often only perceptible in a slightly expressed furrow between the combined central places of attachment — the projecting tip of the central groove. Median swelling of the small shell beginning as a distinctly developed roundish ridge under the hollowed area, between the places of attachment of the central muscles, which are there situated, and ending with a fine short furrow between the places of attachment of the anterior lateral muscles, which are also moved very far back. Principal vessel furrows of both shells deeply sunk, hollowed into plainly round or flat furrows; in the large shell more approximated to the median line and running rather straight; in the small shell more approximated to the lateral borders. Secondary vessels not ramified, radiating inwardly and outwardly perpendicularly to the principal vessels. Peduncular muscles fastened to a toothlike process, which is pushed before the opening of the peduncular groove and reaches freely into the splanchnocoele. The places of attachment of the umbonal muscle, in the large shell, on both sides of the place of attachment of the peduncular muscle on the narrow sides (perpendicular to the plane of the shell border), which stands out into the interior of the shell; in the small shell on a platform, which lies opposite to the place of attachment of the peduncular muscle and projects into the interior like a pier. Combined places of attach- ment of the transmedian and anterior lateral muscles with the large shells in front of the divided places of attachment of the umbonal muscles on the narrow side of the projecting rimlike border of the shell; with the small shell at the corresponding place in similar position to the places of attachment of the transmedian muscles; and in front of these the combined places of attachment of the middle and outside lateral muscles. Places of attachment of the •"entral muscles in the large shell behind those of the outside lateral muscles, lying on both sides of the projecting OBOLID^. 439 tip of the central groove. Both places of attachment narrow, long drawn out, and placed transversely to the shell. On the facing ends of the places of attachment of the outside lateral muscles and divided by the projecting tip of the central groove the small, round, quite deeply depressed places of attachment of the middle lateral muscles. Placed of attachment of the central muscles in the small shell moved far into the excavated tip of the beak, lying under the platform which serves the umbonal muscle as a place of attachment; very much prolonged, divided from one another by the median swelling. Places of attachment of the anterior lateral muscles of the small shell likewise moved very far toward the posterior, lying about in the posterior third of the shell, divided by a fine fm-row at the end of the swelling. Parietal band moved away from the places of attachment in its anterior part, coursing at the border of the scalari- formed terraces of thickening. Observations: The immature shells of this extraordinary species show unmistakably the characters of the genua OholiLS, while these latter are not so easily distinguished in adult individuals. Tliis is especially the case with the characters of the inner surfaces of the shell, which acquire an entirely altered appearance ia consequence of the formation of the shell, which varies in age, and the altered disposition of the thickening of the shell. The relative height of the adult shell is larger than that of the young. In the same mentioned specimens it amounts to 0:171; 0:307; 0:262. The falling off of the arching to the tip of the beak is very flat with the young shell; with the old, as a rule, perpendicular. However, essential aberrances take place with the adult iadividuals; some show the falling off of the beak considerably flattened. As with all other ornamented species, the ornamentation of the outer surface of the shell is altered with the advanc- ing age of the animal. The delicate concentric striation has no waves until the close of the first vegetative period and reminds one with its parallelism (in a strict sense) of that of 0. siluricus. At times, however, it shows some irregu- larities, as the parallel uniformly curved ribs at times flow together or become disturbed. With the beginning of the second vegetative period the waves occur, which, however, are often disturbed inform, and are resolved into separate small swellings. This ornamentation Volborth has fitly named "undulate-humped." Toward the anterior border the swellings are crowded again, the waves become smoother, and the concentric ribs flatten, so that the ornamentation is almost lost close to the anterior border. The construction of 0 . antiquissimus, in comparison with the other Oboli, is somewhat negligent, if we may use that term. The growth lamellae lie very irregularly on one another and protrude very unequally with their anterior sharp borders; at the same time the coherency of the lamelte is so loose that they fall apart at the least occasion. The irregularity of the construction of the shell is shown principally at the posterior borders, at which the lamellae are displaced perpendicularly under one another, and on account of unequal stratification give the appearance of the leaves of an uncut book. The individual rings of the growth lamellae (taking the latter as a whole, not only the visible parts on the surface of the shell) are very massive with 0. antiquissimus, and are club-shaped toward the beak, in the profile, as with other species. But while in the remaining species they at the same time become narrower (crescent-shaped) toward the beak, they here retain their breadth to the traces of the pseudo-area of the area lamellae and then pass over (in the splanchnocoelic part of the area of the base) into a position perpendicular to the plane of the border of the shell. The breadth of the rings (surface of displacement) increases with the advancing age of the shell, independently of whether the existing vegetative period produces a thin or thick lamella. The thickness is understood as the perpen- dicular distance between the surfaces of separation. According to this, the construction of the shell takes place as follows: At the anterior border the growth lamellae are separated. in ordinary manner, each one sticking halfway under the preceding one. Toward the posterior the individual rings are pushed more and more below one another until they lie perpendicularly below one another at the posterior borders of the shell. Now, as every new ring surpasses the preceding in breadth, and the splanchno- coele is nominally reduced in thickness, the rings, which lie perpendicularly upon one another, form a very mas- sively hollowed border, similar to a rim, at the posterior borders of the shell, which is also continued even in the beak. There, however (between the traces of the pseudo-area), they are built up by the lamellae of the splanchno- coelic part of the area, which'' lie in front of one another, perpendicular to the plane of the border of the shell. In the umbonal part of a small shell the described lamellae (which lie over each other) of the posterior lateral borders, as well as the posterior border of the shell which is formed by the splanchnocoelic area lamellae, may be seen distinctly. A principal distinction between the construction of the shell of 0. antiquissimus and that of the other species ia not present. The strengthening of the principal part of the shell (which incloses the visceral cavity) takes place with the first named through strengthenmg of the outer lamellae at the expense of the inner thickening, but with the other species through strengthening of the inner thickening at the expense of the outer lamellae. A noteworthy appearance, which has only been noticed with 0. antiquissimus, deserves to be emphasized. The ring-shaped lamellae of the anterior part of the shell consist of rock-mass (limestone), but are, as all lamellae, clothed with a homogeneous (corneous) layer, so that it gives the impression that the individual lamellae had been hollow and after the death of the animal had been filled with calcareous mud. It is, however, more likely that the inner layer of the canal, which is less capable of resistance, was dissolved after the death of the animal and restored by the penetrating calcareous mud. In still greater measure than through the just described formation of the border the configuration of the inner surface of the shell becomes altered through the disposition of the lamellae of thickening, which deviates in the age of the 440 CAIklBKIAN BKACHIOPODA. animal. The large shell of a youthful specimen is not essentiall)- distinguishable in the general arrangement of the characters from the typical species, unless stress be laid on the extraordinarily strongly shortened splanchnocoele. In one specimen a slight swelling is already noticeable, which, however, does not extend to the splanchnoccele, but, moved from the places of attachment of the muscle far to the front, lies in the brachiocoele. Another already shows the beginning of the formation of terraces in the form of two slight obliquely placed swellings, which are connected in advance growth and widen out to a surface whose border (which faces the beak and falls off perpendicularly) shows an inlet corresponding to the protruded tip of the central groove in the median line of the shell. In further growth of the shells one terrace is built upon the other, each following the other scalariformly, receding from the border of the preceding one and thus gradually forming the mass. This thickening of the shell is extended only on the central part of the shell. At both sides deep, broad fiurows remain, which are retained for the principal vessels. Most likely the mass is gradually flattened toward the anterior border. Unfortunately, all specimens are injured in such a manner that nothing definite could be ascertained. With the small shell the thickening takes place in enthely similar manner. Here the terraces are chieflj' separated by the lateral angular places of the brachioccele, which are formed by the protruding splanchnocoele and form a mass scalariformly sloping, which cuts deep into the protruding splanchnocoele. A youthful specimen of the small shell shows a strongly developed mass, which, however, was for the greater part destroyed by the treatment with dilute hydrochloric acid. This manner of preparation was chosen to lay bare the posterior parts under the deeply hollowed umbonal border, which was also satisfactorily accomplished at the expense of the stronglj'- weathered lamellae of thickening. Of the characters whose development is connected with the thickening of the posterior part of the shell, as the septa, corneous processes, and heart-shaped groove, nothing is to be discovered in the adult shells of 0. antiquissimus. In young specimens, however, the central groove is mostly distinguishable, even if it is always very small, flat, and indefinitely bordered. The principal vessels are sunk in the small shells in the usual manner, but are not divided by a middle swell- ing. With the adult they run in deep furrows at both sides of the central mass. Their course can not be followed in the anterior halt of the shell on account of the injured condition of the shells. The accessory vessels and the peripheral canal are only perceptible in indistinct traces. The former seem to run without branching, and perpendicularly to the principal vessels. The places of attachment of the muscles of 0. antiquismnus h-uve in general the same arrangement as those of the typical species. In the latter those which lie more toward the center of the shell and toward the anterior are, however, corresponding to the disposition of the splanchnocoele, strikingly long drawn out. The peduncular muscle and the divided umbonal muscle are attached in the young shells exactly in the same manner and at the same place on the bottom of the shell of the ventral valve as in the other species. In further growth of the shells small elevations are formed at tife places of attachment. The progressing development of these elevations may be followed in a series of shells. The center one of these elevations is gradually altered through corre- sponding attachment of the lamelte into a toothlike process, which reaches in front of the peduncular groove freely into the splanchnocoele and serves the peduncular muscle as a place of attachment. The places of attachment of the divided umbonal muscle have gradually moved to the rimlike border of the shell (close to the peduncular furrow), whose narrow sides are turned inward. The combined spots of attachment of the transmedian and anterior lateral muscles of the large shell undergo the same change of place. The case is entirely similar with the places of attachment of the small shell, which lie at the base of the area, and the pleurocoele (umbonal, transmedian, outside lateral, and middle lateral muscles). They all move, in the adult indi- viduals, into a place corresponding to their position in the youthful shell, to the narrow side of the rimlike border which surrounds the posterior part of the shell. The place of attachment of the umbonal muscle acquires, aside from this, a special broadening in the form of a pier-shaped platform, which protrudes into the inside of the shell. The pierhke construction gives this place of attachment of the umbonal muscle, which (judging by the mutual attrition of the beaks) displays a considerable strength, a special firmness. All these places of attachment, which he at the border of the shell, are grained like shagreen, coffee-brown colored, and covered with small, lustrous, dark-brown knots. More important than those just described is (in comparison with the typical species) the dislocation of the places of attachment, lying in the interior of the shell. They all are, in consequence of the extraordinary shortening of the splanchnocoele of this species, pushed back so far toward the beak that (especially with the small shell) an entirely distorted figure of the typical figure is brought about. The position of the combined central places of attachment of the large shell is in this regard less striking. The latter are, to be sure, moved so near to the area that only a small triangular space is left for the central groove, but the difference between this arrangement and that -ndth 0. celatus orbiculatus is, however, proportionately slight. Of greater importance is the aberrancy in the opposed position of the individual spot of attachment of this complex, in which, as already often mentioned, the places of attachment of the central muscles are arranged behind those of the outside lateral muscles. The combined central places of attachment could not be demonstrated in the only adult specimen of the large shell; they are lost in the strongly developed configuration of the inner surface. The small shell, on the other hand, presents an entirely singular view. The strongly developed places of attach- ment of the central muscles are, with the young shells, pushed back to the most posterior part of the splanchnoccele, and lie under the platform which serves the umbonal muscles as a place of attachment, and which covers the same. OBOLID^. 441 In the first-mentioned specimen, the entire posterior part is broken off, so that the long-drawn-out elliptic places of attachment (immediately in front of the foot of the broken-off platform) are visible. The second specimen had to be figured from a front view, to make the covered places of attachment visible. Between the places of attachment of the central muscles (which in 0. antiquissimus he nearer one another than with the other species) the slightly developed but distinctly ^dsible median swelling comes in and is produced in the known manner as far as between the places of attachment of the anterior lateral muscle, which are also moved considerably toward the posterior. Formation and locality." — Passage beds between the Upper Cambrian and the Ordovician: "Glauconite limestone " at the following localities: (396i) At Fall, 15 miles (24 km.) west of Reval; (396d) « at Domglint, in Reval; (396h) at Tischer, 10 miles (16 km.) west of Reval; (396j) at Nommeweske, near Palms; (337h [Eichwald, 1860, p. 929]) Orthoceratite limestone near Reval; and (396o) in the entire western part of the east Baltic region; all in the Government of Esthonia, Russia. (396k) "Glauconite limestone" at Iswos on the Wolchow; (396z) limestone in the vicinity of Zarskoe Selo; (395w) chlorite-bearing sands in the limestone beds at Pawlowsk, near St. Petersburg; (336e) Orthoceratite limestone at Pul- kowa, near St. Petersburg; and (3961) "glauconite limestone" at Pulkowa, near St. Petersburg; all in the Government of St. Petersburg, Russia. (396m) "Lower lenticular layer" of the "glauconite limestone" at Saggad, east of Palms; (396n) white Umestone between the "glauconite limestone" proper and the sandy representatives of the "Vaginatum limestone," at Leppiko, near Leetz, on the eastern side of the Baltischport Peninsula, about 25 miles (40.3 km.) west of Reval; (396g) upper limestone at Reval; (396x) chlorite-bearing sands in the limestone beds at Baltischport, about 30 miles (48 km.) west of Reval; (396y) chlorite-bearing sands in the limestone beds at Reval; (336d) Orthoceratite limestone at Reval; and (396p) strata between the "lower lenticular layer" and the "^'aginatum limestone" proper, at Nommeweske, near Palms; all in the Government of Esthonia, Russia. (386b) Drift blocks of "glauconite limestone" near Wehlau, 30 miles (48 km.) east of Konigsberg, East Prussia, Germany. Obolus (Acritis?) rugatus Walcott. Plate XIII, figure 2. Obolus (Acritis?) rugatus Walcott, 1901, Proc. U. S. Nat. Mus., vol. 23, p. 694. (Characterized as a new species.) The concentric surface lines which are the characteristic feature of this sheh, although much coarser, are the same type as those of 0. {Acritis) antiquissimus (Eichwald) and termmate on the posterolateral margms m much the same manner. It is a very rare form, only one specimen having been collected, although the beds iq which it occurs were very thoroughly searched during the survey of the Eureka mining district. All that is known of the species is shown by the figure illustrating it. It is probably not an Acritis and probably not an Obolus. The peculiar surface, as shown in Plate XIII, figure 2, is very much like that of a Silurian species named by Clarke Glossina acerJ' This form owes its specific name to tlte coarseness of the concentric surface lines. Formation and locality. — Middle Cambrian: (58) Shaly limestone in upper beds of Secret Canyon shale, east side of New York and Secret canyons. Eureka district [Hague, 1892, Atlas], Eureka County, Nevada. SCHMIDTIA Volborth.c subgenus of OBOLUS. Schmidtia Yoi.BORin, 1860; see Marshall's Nomenclator Zoologicus, p. 137. Not Schmidtia Balsamo-Crivelli, 1863. (Proposed for a genus of Porifera.) Schviidtia Volborth, 1869, Verhandl. Russ.-kais. min. Gesell. St. Petersburg, 2d ser., Bd. 4, pp. 208-209. (Discussed in German.) Schmidtia Volborth, Dall, 1877, Bull. U. S. Nat. Mus. No. 8, p. 62. (Notes on use of generic name Schmidtia). Schmidtia Volborth, Zittel, 1880, Handbuch der Pateontologie, Bd. 1, Abth. 1, p. 665. (Described in German.) Schmidtia Volborth, Oehlert, 1887, Manuel de conchyliologie, by Fischer, p. 1263. (Described in French.) Schmidtia Volborth, Hall and Clarke, 1892, Eleventh Ann. Rept. State Geologist New York for 1891, p. 244. (Described.) Schmidtia Volborth, Hall and Clarke, 1892, Forty-fifth Ann. Rept. New York State Museum for 1891, p. 560. (Copy of preceding reference.) a Locality 396d is represented in tlie collections of the United States National Museum. With the exception of Locality 337h the remaining localities are cited from Mickwitz [1S9G, p. 213]. 6 Clarke, J. M., New York State Museum, Memoir 9, 190S, pp. 214-216, PI. XLVII, figs. 7 and 8. c The synonymy for this subgenus does not give a complete record of the various genera under which the species now included in Schmidtia were formerly placed: it gives only those references in which the genus is discussed or described. To complete the record the following mere generic references are listed: rrngula Pander [1830, p. 59). Ololus {Lingulella) Walcott [1898b, PI. XXVI, figs. 1 and 2]. Obolus Wimau [1902, pp. C2 and 63]. Obolus Moberg and Segerberg [1906, p. 65]. Obolus Westerg4rd [1909, p. 56]. 442 CAJMBRIAN BRACIIIOPODA. Schmidtia Volborth, Hall and Clarke, 1892, Nat. Hist. New York, Palaeontology, vol. 8, pt. 1, p. 83. (Discussed.) Obolus {Schmidtia) (Volborth), Mickwitz, 189G, M6m. Acad. imp. sci. St.-P6tersbourg, 8th ser., vol. 4, No. 2, p. 158. (Described and discussed in German; see below for translation.) Obohis (Schmidtia) (Volborth), Walcott, 1901, Proc. U. S. Nat. Mus., vol. 23, p. C83. (Characterized.) Obolus (Schmidiia) (Volborth), Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 4, PI. XI, and pp. 142 and 144. (Classification of genus.) The original description by Mickwitz follows : The subgenus Schmidtia, out of all the subgenera of Eichwald's genus, is most closely related to the subgenus Eu- obolus. Some species of that subgenus, especially 0. celatus and to a less degree 0. crassus, show in theu- general appear- ance so much resemblance to 0. apoUinis that they might pass for miniature models of it. The other two species, on the contrary, depart from the typical species in the form of the valves and in the shape of the area; 0. obtusus, in outline and in the flatness of its valves, rather resembles Lingula, while 0. acuminatus has a very peculiar form, differing from all Oboli, and due in pai-t to the peculiar conformation of the apex of the beak. The main arguments for establishing a special subgenus Schmidtia alongside of the subgenus Euobolus, aside from the exti-aordinary smallness of the valves, are: the absence of radial stria tion of the surface of the valve; the absence of longitudinal striation from the slope of the thickened posterior part of the valve, as well as of the posterior edge of the central pit; the invariably more uniform thickening of the valves, manifested in this, among other things, that the plem-occelic parts of the valves differ in nothing from the frontal and side edges; the fact that the area of the large valve is broken in the plane of the pedicle furrow; the pit-shaped depression of the splanchnocoelic part of the area of the small valve; the pestle-shaped form of the central pit; the recession of the horn-shaped projections and of the sinus of the small valve, while the median ridge simultaneously predominates. A further difference seems to exist in the different conformation of the inward-radiating secondary vessels, which in some species of the subgenus Schmidtia are variously ramified, whereas in the subgenus Euobolus, so far as can be seen, they are more I'ectilinear and less branched. Still the knowledge of these organs in the species of the two subgenera is as yet too imperfect to permit a definite statement. Type. — Schmidtia celata Volborth. Observations. — The reasons stated by Mickwitz [1896, p. 158] for establishing Schmidtia as a subgenus of Obolus are essentially those that differentiate it from Lingulella. The species of the latter subgenus are radially striated and the shells are uniformly thinner. So far as known, all of the species of Schmidtia are those described by Mickwitz from the Obolus beds of Russia. In order to place before the student full details of the species, I have had drawings made from the original specimens received from Mickwitz, and have also introduced the greater portion of his detailed descriptions. In order also that there may be a reference in this monograph to the varieties Mickwitz has determined, .these are included in the synonymj^ of the different species referred to Schmidtia. The subgeneric name was given in honor of Dr. Fr. Schmidt, of St. Petersburg, Russia. Obolus (Schmidtia) acuminatus Mickwitz. Plate XIV, figures 2, 2a-c. Obolus (Schmidtia) acuminatus Mickwitz, 1896, M6m. Acad. imp. sci. St.-P6tersbourg, 8th ser., vol. 4, No. 2, pp. 179- 183, PL II, figs. 39 and 40. (Described and discussed in Geiman as a new species; see below for translation.) Obolus (Schmidtia) acuminatus alatus Mickwitz, 1896, idem, pp. 183-184, PL II, figs. 41 and 42. (Described and dis- cussed in German as a new variety.) Obolus (Schmidtia) acuminatum humeratus Mickwitz, 1896, idem, pp. 184-186, PL II, figs. 43 and 44. (Described and discussed in German as a new variety.) Obolus (Schmidtia) acuminatus subtriangularis Mickwitz, 1896, idem, pp. 186-187, PL II, figs. 45 and 46. (Described and discussed in German as a new variety.) The original description by Mickwitz follows : This remarkable species comprises, as the preceding, a number of forms essentially deviating from one another (especially in outline), whose unity can be safely asserted only by the agreement of certain characters important for the distinction of different species of the subgenus Schmidtia. To these belong, in the first rank, the peculiarly devel- oped beak, with the aberrantly placed indications of a pseudo-area, which stands in a certain opposition to that of 0. obtusus. The latter shows, as we have seen, this part of the shell flat, obliquely truncated, and the traces of a pseudo-area far removed from the peduncular groove. With 0. acuminatus, on the contrary, the beak is highly arched, inwardly bent, and the traces of a pseudo-area coincide with the borders of the peduncular groove. Diagnosis: Shells small; large shell (ventral valve) strongly arched, small shell (dorsal valve) more weakly. Greatest height of both shells directed more toward the beak. Outline oval. Beak of the large shell high, pointed, falling off steeply toward the tip of the beak and the umbonal borders. Tip of the beak bent inward. Anterior border OBOLID^. 443 of the large shell somewhat receding from the plane of the lateral borders. Beak and anterior border of the small shell somewhat projecting beyond the same. Shell borders thin, sharp edged, in the small shell formed like the border of a plate. Outer surface of the shell polished, somewhat irregular because of unequally deeply cut concentric furrows, and rough toward the front because of the projecting borders of the lamellae. Area small, in the large shell triangular; in the small, shaped like a band. Splanchnoccelic part of the large shell reduced to the borders of the peduncular grooves; with the small excavated into narrow furrows. Pleurocoelic parts of the large shell deeply hollowed out; in both, at the base, posteriorly somewhat caudate, extended, and drawn out into the lateral borders. Peduncular groove parallel-bordered, narrowing as a rule toward the apex of the shell in the excavation of the area supported by a bridge. Traces of a pseudo-area on the large shell coinciding with the borders of the peduncular groove or running very close to the same; in the small shell in similar position, including between them the nari'owly grooved, excavated, splanch- noccelic part of the area surface. Shell thickening slight. Median septum under the magnifying glass mostly perceptible, in the large shell often in connection with the bridge supporting the peduncular furrow. Lateral septa receding. Median swelling of the small shell plainly developed, between the places of attachment of the anterior lateral muscles in the form of a sharp ridge. Posterior part of the central depression very widely extended; anterior part parallel-bordered, at the tip scarcely broadened. Observations: 0. acuminatus is, next to 0. ohtusus, the most characteristic species of the subgenus. The most essential differences of these two species, which lie in the formation of the beak, have been referred to in the beginning. For the rest they also differ so far from each other in the form and size of their shells that a confusion of them is pre- vented. The external characters which separate 0. acuminatus from the two other species of the subgenus Schmidtia are less striking. From 0. celatus the species now in question is separated externally principally through the oval outline, in the more considerable height of their shells, whose greatest height lies more toward the beak; from 0. crassus, to which it is closely related in relation to the outline and height of the shell, through the steeper falling off of the arching toward the tip of the beak. The shells of the last-named species have likewise an oval outline, but the relative breadth of the same is greater. Also the arching of the shells in 0. crassus is somewhat stronger in the middle, but the greatest height lies more toward the center of the shell. The S-shaped section of the border of the large shell of 0. acuminatus, to which a slight concavity in the small shell corresponds, was also noticed in 0. celatus pr^dsus; but here also the broad oval outline of the shells of this variety and the flat falling off of the arching of the tip of the beak give a certain and distinctive external character. The relations are shown more clearly by comparing the average characters of the respective relative numbers than by figures and descriptions. The aberrant characters, which are present in the interior of the tip of the beak, are by far more important for the distinction of the species than the external differences of form. The most characteristic among these is the position of the traces of the pseudo-area, which in 0. acuminatus run parallel and coincide with the peduncular groove; in 0. celatus and 0. crassus, however, they are removed from the latter and converge posteriorly. The form of the shells of 0. acuminatus shows but slight deviations. In some specimens the highly arched beak of the large shell, which falls oft steeply posteriorly and laterally, is somewhat more sharply pointed and the tip of the beak seems to be compressed toward the side. In others the S-shaped section of the border of the large shell is more slightly wavy, but in the differences of form no rule can be perceived. It is similar with the small shells. In regard to regularity, however, the outer surface of the shell seems to be subject to greater deviations than the foregoing species in their concentric striations. Besides forms with entirely smooth and lustrous shell surfaces, some occur that have very irregularly deep sculptured concentric furrows, which become especially irregular toward the anterior border and give the shells a dull aspect. The area is in both shells very unevenly striate, and in the large shells, on account of the fracture in the pedun- cular furrow and the somewhat incurved tip of the beak, it is, as a rule, slightly excavated. With normally built shells the traces of the pseudo-area show slight inclination to separate themselves from the borders of the peduncular fur- row; and the de^dations (which some specimens pointing to the variety alatus show in this direction) are always very small. In the small shell, whose traces of a pseudo-area lie opposite those of the large shell, these deviations show themselves in a greater breadth of the furrow similar to the peduncular groovelike furrow which forms the splanch- noccelic part of the area. The crowding of the splanchnocoele into the beak of the large shell (which is conditioned by the high arching and the uniformly slight thickening of the same) is only a more marked form of the groove-shaped excavation of the base of the area. Shells whose beaks are more flatly arched show as a rule a more distinct thickening of the posterior part, and, in connection therewith, an unexcavated, massive tip of the beak. The same is also the case with the small shells of this species. Likewise the bridge supporting the peduncular furrow is foreshadowed in that the groovelike hollowing out of the base of the area at the mouth of the peduncular furrow is transplanted into the splanchnoccelic part. The inner configuration of the shells is, on account of the defective thickening, as a rule slightly pronounced. An exception is formed by the spots of attachment of the central muscles of both shells and the median swelling of the small shell, which are always easily perceptible. The former are shown deejjly sunken in the large shell, and in the roundish form characteristic for the Schmidtias, while the laterally situated places of attachment of the outside lateral muscles are only slightly deepened, but are separated from those by a distinct ridge. In a small shell the places of attachment of the central muscles appear in the form of strong protuberances. The median swelling is, in opposition to that of 0. ohtusus, at its anterior border (between the places of attachmeiit of the anterior latejral muscles) undivided, and posteriorly united with the feeble median septum. In a large shell the latter appears as a very sharp, small ridge. 444 CAi'IBRIAN BRACHIOPODA. Of the remaining; places of attachment of the muscles there are also plainly to be seen the ones lying in the neigh- borhood of the area in the small shell, while they are lost, in the large shell, in the border of the excavation. The central depression in the large shell is always very shallow. Of the circulatory system are to be distinguished only the posterior ends of the principal vascular canals, under the magnifying glass. The accessory vessels and the peripheral canals, on the contrary, are so feebly developed on all the observed speci- mens that only indistinct traces are perceptible by reflected light. Formation and locality. — TJpper Cambrian: Obohis sandstone at the following localities: (395)a at Joa, near Jcgelecht, 12 miles {19.S km.) east of Reval; (396a) at Tihala, near Togelecht; (395b) at Ilgast; (395c) at Asserien, 75 miles (121 km.) east of Reval; (395d) at Ontika, about 95 miles (153 km.) east of Reval and 30 miles (4S km.) west of Narwa; and (395e) at Isenhof, So miles (137 km.) east of Reval; all [Mickwitz, 1896, p. 183] in the Government of Estlionia, Russia. Oboi.us (Schmidtia) celatus (Volbortli). Plate XIV, figures 1, la-c. TJngula ovata Pander, 1830, Beitrage zur Geognosie des russischen Reiches, p. 59, PL XXVIII, fig. 6a-b (not PI. Ill, fig. 23, refeiTcd to Obolus apolUnis). (Characterized in German.) SchmidtiacelataYohBO-RTn, 1869, Verhandl. Russ.-kais. min. Gesell. St. Petersburg, 2d ser., Bd. 4, pp. 209-212, PL XVII, figs. 1-6. (Described and discussed in German as a new species.) Schmidtia celata Volborth, Hall and Clarke, 1892, Eleventh Ann. Rept. State Geologist New York for 1891, p. 244, figs. 248 and 249. (No text reference. Figs. 248 and 249 are copied from Volborth [1869, PL XVII, figs. 1 and 4, respectively].) Schmidtia celata Volborth, Hall and Clarke, 1892, Forty-fifth Ann. Rept. New York State Museum for 1891, p. 560, figs. 248 and 249. (Copy of preceding reference.) Schmidtia celata Volborth, Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, p. 83, figs. 37 and 38. (No text reference. Figs. 37 and 38 are copied from the figures given in the two preceding references.) Obolus {Schmidtia) celatus (Volborth), Mickwitz, 1896, Mem. Acad. imp. sci. St.-P6tersbourg, 8th ser., vol. 4, No. 2, pp. 159-163, PL II, figs. 19 and 20. (Described and discussed in German; see below for translation.) Obolus (Schmidtia) celatus orbiculatus Mickwitz, 1896, idem, pp. 163-165, PL II, figs. 21 and 22. (Described and dis- cussed in German as a new variety.) Obolus {Schmidtia) celatus prxcisus Mickwitz, 1896, idem, pp. 166-167, PL II, figs. 37 and 38. (Described and discussed in German as a new variety.) Obolus (Lingulella) celatus (Volborth), Walcott, 1898, Proc. U. S. Nat. Mus., vol. 21, PI. XXVI, figs. 1 and 2. (No text reference. The specimens represented by figs. 1 and 2 are redrawn in this monograph, PL XIV, figs, la and Ic, respectively.) Obolus celatus orbiculatus (Mickwitz), Wiman, 1902, Bull. Geol. Inst. Univ. Upsala, vol. 6, pt. 1, No. 11, p. 62. (New locality mentioned in German.) Obolus celatus orbiculatus (Mickwitz), Moberg and Segerberg, 1906, Medd. fran Lunds Geol. Faltklubb, Ser. B, No. 2 (Aftryck ur K. Fysiografiska Sallskapets HandL, N. F., Bd. 17), p. 65. (Mentions locality given in pre- ceding reference, in Swedish.) Obolus celatus orbiculatus (Mickwitz), WestergArd, 1909, Medd. fran Lunds Geol. Faltklubb, Ser. B, No. 4 (Aftryck ur K. Fysiografiska Sallskapets HandL, N. F., Bd. 20), p. 56. (Locality mentioned in Swedish.) The original description by Mickwitz follows : This species was first described hy Volborth, who also gave us the first knowledge of a part of the places of attach- ment of the muscles. The first figure of a small shell is, however, found in Pander's above-cited work as TJngula ovata; but this drawing lacks all internal characters with exception of the plate-shaped border of the shell, which Volborth also mentions. Much more exact drawings of a whole series of Schmidtias (without names or description) are preserved to us in a sheet among the papers left by Pander, which was kindly handed over to me by Professor Lahusen. The places of attachment of the muscles, especially of the small shells, are in some of these figures present in full proportion, but, to be sure, not disentangled as their individual constituent parts. Also on one specimen of a large shell are plainly designated the principal and accessory vessels (which radiate inwardly). I have not utilized these drawings in any present work, because my material is much more complete than that of Pander, and, moreover, the species described by me could not with sufficient certainty be identified with the drawings in question. Diagnosis: Shells small, slightly arched; arching of the small shell slighter than that of the large shell. Outline of the shells roundish, umbonal border of the large shell rectilinear. Surface of shell very smooth and lustrous; con- • centric striation very fine, in thickness somewhat irregular. Anterior {Stirn) and lateral borders thin, sharp margined; those in the small shell usually somewhat thickened, with the umbonal borders lying in one plane. Area small, in the large shell slightly interrupted in the peduncular fm-row; in the small shell, in the splanchnocoelic part, deepened o Locality 396 is represented in the collections of the United States National Museum. OBOLIDiE. 445 into a depression; peduncular furrow shallow but plainly developed, slightly diminished toward the tip of the beak. Traces of a pseudo-area bent slightly concave to the area lamellse at the median line of shell, converging into the tip of the beak. Shells almost uniformly thick, toward the beak only a little thickened. Traces of the principal vessels broad, shallow, little prominent ; middle swelling and lateral furrows of the same scarcely projecting. Secondary, inwardly radiating vessel traces in the large shell in the principal direction perpendicular to the principal vessels; in the small one curved anteriorly, in both very indistinctly ramified. Central groove of large shell pestle-shaped, with a slight swell. Apex of central groove relatively broad, somewhat drawn out, parallel-bordered, generally some- what involved with the combined central places of attachment of the muscles. Median swelling of small shell dis- tinctly developed, growing over into the median septum, at times separated by a fine median groove. Corneous jjrocesses and sinus receding very much. Observations: 0. celatus varies as all Obolus species in its external form and internal configuration of its shells. The want of space, however, forbade the illustration of these alterations in a manner similar to that used for the prin- cipal species of Eichwald's genus. I had to restrict myself to the illustration of the extreme members of the series of forms. This remark concerns all species of the subgenus Schmidtia. Aside fi'om the form figured by Volborth, some with circular outline and others with flattened anterior border occur, which are connected with the principal forms by transitions and were demonstrated in their extreme members as 0. celatus orbiculatus and 0. celaf.us prxcisus. To all members of this group, brought together as 0. celatus, a note- worthy peculiarity of accessory nature is common which is lacking in the remaining species of the subgenus Schmidtia, and which, therefore, may be looked upon as a fm'ther argument for the cospecificity of the forms mentioned. This peculiarity is a fine netlike coating, which may be found on many of these shells and which often covers the surface of the shell in several superimposed layers in the form of crusts. It may indicate the existence of a bryozoan. Traces of the netlike coating are, however, also found in the specimens of the variety prxcisus. The tip of the beak and the anterior border of the large shell deviate in some specimens from the normal character in such a manner that both recede somewhat from the level of the border of the shell; then in the corresponding small shell the reverse occm's so that the closing of the shell is secured. The receding of the beak is nevertheless never so strong as, for example, in 0. obtusus. The flat plate-shaped border [Volborth, 1S69, p. 210] of the small shell is formed by the last separated lamella of the border, which is marked off from the remaining surface by the principal vessel furrows which course along its inner border, and, in consequence of the flatness of the small shell, it stands out more distinctly. In the large shell the principal vessel furrows are moved more toward the interior of the splanchnocosle, and as the shell also has a stronger arching, the lamella? of the border recede farther. Besides, this formation, which is found in all species of the subgenus Schmidtia, is very variable in its strength and in some small shells hardly perceptible. On the other hand, it at times also occurs in the large shells in which the peripheral canals play the same part as the principal vessel furrows. The surface of the area of the large shell in this species of the subgenus Schynidlia is least broken in the peduncular furrow, and the area itself reminds one of that of the tj^pical species, especially in that the traces of the pseudo-area of the area lamellse converge into the tip of the beak. The pleuroccelic parts of the area of both shells are only slightly prolonged into the lateral borders. On the other hand, the area of the small shell deviates from that of 0. apollinis by the deepening of its splanchnocoelic part, which possesses in consequence of the special position of the traces of the pseudo-area in this species a subtriangular form. The form of the central groove varies within rather wide limits. Through lateral restraint of the posterior part of the protruded parallel-bordered tip there results an irregular biscuit-shaped outline, and through compression of the posterior broad part of the central groove in the median direction, a simultaneous shortening and tapering of the anterior part. Some shells show the protruded tip laterally compressed, so that only a narrow groove is left, which is then as a rule inclosed by strong swellings. In others this groove possesses a breadth which almost equals the posterior part of the central groove. All these alterations of form, which seem subject to no law, are also peculiar to all other species of the subgenus. The side septa and median septum are, even if slightly, developed in both shells. The former as a rule stand out more distinctly in the large shells; the latter, however, in the small ones, where it is more distinctly expressed, appears as a prolongation of the always strongly pronounced median swelling. The corneous processes and the sinus of the small shell are rarely to be distinguished. Yet in some specimens, in reflected light under a lens, two fine ridges are seen, which converge from the external sides of the places of attach- ment of the central muscles toward the beak and, with the median swellihg, form a triradiate figure. In spite of their minuteness the places of attachment usually stand out distinctly, especially those of the central muscles, which in both shells as a rule are let down deeply with swelled borders. Also the separation of the combined places of attachment is attained with the help of a lens, although naturally with more difficulty than in the larger forms of Eichwald'sgenus. It is very difficult to perceive the places of attachment of the transmedian and the combined places of attachment of the outside and middle lateral muscles in the small shells. The places of attachment of the central muscles, as also those of the outside and middle lateral muscles of the large shell, have more roundish forms and are not so closely connected as in the species of the subgenus Euobolus. Noteworthy is also the somewhat deviating position of the places of attachment of the central and anterior lateral muscles in the small shell. The direction of the longitudinal axes converge, in the former toward the beak, in the latter toward the anterior border. As these places of attachment have in by far the most cases a pronounced elongate form, this position is very striking and was also noticed by former observers [Volborth, 1869, p. 210]. 446 CA^IBRIAN BRACHIOPODA. Little is to be said of the vessels. It is the easiest, especially in the small shells, to distinguish the peripheral canals, which lie on the plate-shaped border and are usually perceptible under the lens. It is more difficult to per- ceive the principal vessels. They easily lose themselves in the small shell in the terrace of the plate-shaped border and are but seldom perceptible in the large shell in spite of their freer position. The lateral vessels sink in their minuteness to microscopic sizes and are distinguishable only in exceptional cases by use of strong enlargement. This is particularly the case in the ramifications, which are very indefinite in this species. The figured specimens allow the vessel system to be perceived very faintly under the lens. As a rule the parietal band is seen, and it is also faintly suggested in the figures. In the small shell it also stands out on account of the fine-grained character of the splanchnoccelic part of the shell. Formation and LOCALrry." — Upper Cambrian: Obolus sandstone at the following localities: (395) At Joa, near Jegelecht, 12 miles (19.3 km.) east of Reval; (395a) at Tihala, near Jegelecht; (395b) at Ilgast; (395c) at Asserien, 75 miles (121 hm.) east of Reval; (395d) at Ontika, about 95 miles (153 km.) east of Reval and 30 miles (48 km.) west of Narwa; and (395e) at Isenhof, 85 miles (137 km.) east of Reval; all in the Government of Esthonia, Russia. Obolus conglomerate at the following localities: (395g) At Joa, near Jegelecht, 12 miles (19.3 km.) east of Reval; (395h.) at Tihala; (3951) at Ilgast; (395j) at Asserien, 75 miles (121 km.) east of Reval; (395k) at Ontika, about 95 miles (153 km.) east of Reval and 30 miles (48 km.) west of Narwa; (3951) at Isenhof, 85 miles (137 km.) east of Reval; all in the Government of Esthonia, Russia. Sandstone below the Obolus conglomerate at the following localities: (395in) At Joa, near Jegelecht, 12 miles (19.3 km.) east of Reval; (395n) at Tihala; (395o) at Ilgast; (395p) at Asserien, 75 miles (121 km.) east of Reval; (395q) at Ontika, about 95 miles (153 km.) east of Reval and 30 miles (48 km.) west of Narwa; and (395r) at Isenhof, 85 miles (137 km.) east of Reval; all in the Government of Esthonia, Russia. (336o) Ungulite gritat Koporje, Government of St. Petersburg; and (336p) Ungulite grit at Kunitz, Government of Pskow; both in Russia. Schmidtia conglomerate (part of the Obolus conglomerate) at the following localities: (396s) At Asserien, 75 miles (121 km.) east of Reval; (395t) at Ontika, about 95 miles (153 km.) east of Reval and 30 miles (48 km.) west of Narwa; and (395u) at Isenhof, 85 miles (137 km.) east of Reval; all in the Government of Esthonia, Russia. (321d) Drift bowlder of Obolus sandstone. No. 21 [Wiman, 1902, p. 68], on Fanton Island, parish of Borstil, Province of Stockholm, Sweden. Obolus (Schmidtia) ceassus Mickwitz. Plate XIV, figures 4, 4a-d. Obolus (Schmidtia) crassus Mickwitz, 1896, Mem. Acad. imp. sci. St.-P6tersbourg, 8th ser., vol. 4, No. 2, pp. 187-193, PL II, figs. 47-49, 52-55. (Described and discussed in German as a new species; see below for translation.) Obolus (Schmidtia) crassus angulatus Mickwitz, 1896, idem, pp. 193-194, PL II, figs. 50 and 51. (Described and discussed in German as a new variety.) . The original description by Mickwitz follows : Obolus crassus is the most abundant species of the subgenus Schmidtia. Its shells are massively built and to this circumstance we are indebted for the remarkably strong development of all the internal characters, a development which has been of the greatest importance in rendering possible the determination of the organization of the genus Obolus Eichwald. With the large choice of well-preserved shells, specimens are found which preserve the finest detail, as, for example, the outwardly and inwardly radiating accessoiy vessels, the opening of the principal vessels of the large shell into the peripheral canal, etc. This development of the inner characters, standing alone among all the Obolus species, which, so to speak, forms the basis of the anatomical part of the present work, and in many doubtful cases has proved decisive, was the cause of directing to the shells of 0. a'assus especial attention, which finds expression in the increased number of figures and measurements. Diagnosis: Shells small, thick. Large shell (ventral valve) strongly arched, small shell (dorsal valve) less so. Outline of shells broadly oval, umbonal borders convex. Surface of the shell faintly polished; concentric striation rather fine, not uniform. Growth lamellas bordered by quite deeply engraved lines, toward the anterior border not strongly projecting. Shell borders massiye, blunt; plate-border formation slightly developed. Anterior border and tip of the beak of the large shell mostly receding a little from the plane of the lateral border; in the small shell projecting. Area very large, triangular, unevenly striate. In the large shell somewhat broken in the peduncular groove; in the small one slightly deepened in the splanchnoccelic part; in bgth slightly excavated into furrows at the ■• almost rectilinear base. Peduncular groove deeply cut, narrowing slightly toward the tip of the beak. Traces of the pseudo-area strongly developed, rectilinear, more or less converging posteriorly, separating the lateral borders. Thickening of the shell quite regular, somewhat stronger at the splanchnoccelic part. Septa of both hardly per- ceptible. Corneous processes of the small shell suppressed by the strongly developed median swelling, which includes the entire protruded splanchnocoele and fills the sinus. The median swelling has a fine median furrow at the anterior border. Central groove of the large shell as a rule deeply sunken and bordered by swellings. Posterior part very broad, anterior projecting tip parallel-bordered. a Locality 395 is represented in the collections of the United States National Museum; the remaining localities are taken from the references given in the synonjiny. The authority for each locality cited is given in the list of localities, pp. 161-291. OBOLID^. 447 Principal vessel furrows broad and flat. Central swelling of same slightly pronounced. Central swelling of the peripheral canals mostly separated into square sections by finrows which are parallel, directed obliquely outward, and which subside posteriorly. Secondary inwardly radiating vessel furrows strongly and irregularly branched; in the large shell perpendicular in their principal direction to the principal vascular canals; the posterior ones running out into the interior of the brachiocoele, those more anteriorly placed bending toward the peripheral canal and opening into the same. In the small shell these furrows take an oblique direction, anteriorly and internally from the lateral parts of the principal vascular canals but posteriorly and externally from the parts turned off toward the places of attachment of the anterior lateral muscles. Secondary outwardly radiating vascular traces in both shells rectUinear, perpendicular to the principal vascular fiuTows, plainly forked, close before the opening into the peripheral canal. Places of attachment of the muscles in both shells strongly sunken, those of the central and outside lateral muscles of the large shell oval, somewhat separated from one another by a small swelling. Parietal band in both shells plainly developed, normally running out, brought out through the fine-grained condi- tion of the surface. Observations: 0. crass^us reminds one, in the form of its shell, of 0. acuminatus in relation to the position of the traces of the pseudo-area; it takes, on the contrary, an intermediate position between 0. celaius and 0. obtusus. The relations to 0. acuminatus have already been mentioned (p. 443). Further, at the same place it was pointed out that the traces of the pseudo-area of both species (0. crassus and 0. celatus) converge posteriorly. The difference in the position of the converging pseudo-areas of the two last-named species is, however, very essential and consists in the fact that in 0. celatus the same opens into the tip of the beak; with 0. crassus, on the contrary, the borders of the area intersect at a certain distance from the beak. The last can, under some circumstances, become so large that the traces of the pseudo-area maintain a subparallel position which reminds one of that in 0. obtusus. A confounding of the two species in this rarely occurring case is meanwhile excluded on account of the high triangular area and the deviating form of the shell of 0. crassus. In a majority of the shells the convergence of the traces of the pseudo-area is dis- tinctly pronounced. The high, coarsely striate area has a plump form in consequence of the pleurocoelic part being only slightly drawn out into the lateral borders, and on account of its convex external borders, which contrast strongly with those of 0. celatus. Its base runs almost straight, is always composed, in common with the other species of the genus Obolus, of three shallow curves, and is slightly grooved; tip in the large shell usually recedes somewhat from the plane of the shell borders. The break in the surface of the area in the large shell, in the peduncular, is insignificant but somewhat stronger than in 0. celatus; the sunken splanchnocoelic part of the area in the small shell has a trapezoidal form, in consequence of the spfecial position of the traces of the pseudo-area, and is somewhat hollowed out in the median direction. * * *■ The profile of the shell borders shows in both shells, as a rule, a straight line; in the small shell it is at times slightly bowed concavely. The shell borders themselves are, corresponding to the thick condition of the shells of this species, thicker and less sharp than with the other species of the subgenus Schmidtia. The external surface of the shell possesses a rather coarse concentric striation, which becomes somewhat stronger toward the anterior border, but does not stand out in the projecting intricate form as observed in other species of the subgenus. The character of the internal surface of the shell offers in general the same picture which we have learned to know in 0. celaius. With the majority of the shells the central pit has the normal, pestle-shaped form, and is inclosed by a more or less pronounced swelling. One specimen shows the latter at the posterior border and on the sides of the depression swollen up. With another specimen it is, on the contrary, entirely absent and the central depression appears shallowed and indefinitely bordered. This shell is in a somewhat abnormal condition. It shows in profile an arrest of growth through which the greatest height is shoved toward the beak. At the same time it shows the places of attachment of the central muscles as thick protuberances — especially on the right side. The septa of both shells are very weakly developed, likewise the corneous processes of the small shell, which, as with all Schmidtias, recede before the powerfully developed median swelling. The latter is in its anterior half provided with a fine median gi-oove. In reference to the places of attachment of the muscles of 0. crassus there is nothing essential to be added to the condition found in the other Schmidtias. They are found here in exactly the same position and condition as in the other species of the subgenus, so far as the modified form of the shells does not condition slight alterations. It is at all events to be insisted upon that these characters in the present species are found in a condition of distinctness, which the remaining species of the subgenus do not show in equal degree. Into the circulatory system of 0. crassus, on the contrary — which, through its prominent development and preser- vation, explains many conditions which, in the other species, must remain undecided — I shall enter more closely. The principal vessels of the large shell of this species are moved somewhat nearer to the median line than in 0. celatus and at times acquire a subparallel position. This character, nevertheless, is extremely variable and is dependent on the form of outline of the shell. Broader forms show these traces more approximated to the border of the .shell. In the small shell the principal vessel furrows run in the manner known near the border of the shell and parallel to the same. The opening of the principal vascular canals of the large shell into the peripheral canal is plainly to be seen under a lens by reflected light. * * * The peripheral canals show a peculiar formation, which hitherto has not been noticed in the other species of the subgenus Schmidtia. The median swelling of the peripheral canals (especially at its posterior parts) is separated by short, obliquely placed cross furrows, which anteriorly run inward, posteriorly outward, into a series of small square sections, which as a whole resemble a twisted ribbon. This character is somewhat inconstant and seems to appear 448 CAjMBRIAN brachiopoda. only in those shells whose characters, upon the whole, are strongly pronounced. It is self-e\adent that such fine particularities are only perceptible by strong magnification in reflected light; they could not be distinctly reproduced without impairing the value of the figures. The secondary vessels, which radiate inwardly, vary essentially both in their course and in the manner of their ramification. In the large shell, as a rule, they ramify rectilinearly and perpendicularly to the principal vessels and throw off short branches to both sides; only those which lie more anteriorly ciu^e toward the anterior border and open between the principal vascular furrows into the peripheral canal. The accessory vessels run out entirely different in another specimen. Here they fork shortly after branching off from the principal vessels and take their course to the posterior part of the shell. Nothing is to be seen of an opening into the peripheral canal of the anterior border. Lastly, another shell, where these organs leave the most indistinct traces, shows an irregular confusion of treelike ramified canals, the directions of which seem to alter by every turning of the shell under the lens. The accessory vessels of the small shell, which radiate inwardly, show simUar differences. As a rule, the accessory vessels issuing from the central part of the principal vessels, ttnm anteriorly immediately after their exit from the latter, and are slightly curved in the shape of an S and hardly ramified. Only those lying at the extreme back bend into the angular spaces of the brachioccele, which are formed by the parietal band; the accessory vessels, however, which ramify from the anterior, inwardly bent ends of the principal vessels, run rectilinearly posteriorly. Another specimen, however, shows the central accessory vessels directed more posteriorly and very strongly ramified. WTiat significance these essential deviations have in the systematic aspect can not, however, be established at present. No correlation has hitherto been obtained. The secondary outwardly radiating vascular traces correspond, in all examined specimens, in regard to their ' arrangement and coiu^e. Branching off perpendicularly to the principal vessels, the straight, short traces fork before opening into the peripheral canal. As in 0. celatus, the parietal band may be followed as a fine ftuTowed swelling, and where perceptible traces are lacking it is often established through the difference in the character of the siuface of the splanchnocoele and brachioccele. This form owes its specific name to the massiveness of its shells. FoRjiATiON AXD LOCALITY. a — Upper Cambrian: Obolus sandstone at the following localities; (395) At Joa, near Jegelecht, 12 miles {19.3 km.) east of Reval; (395a) at Tihala, near Jegelecht; (395b) at Ilgast; (395c) at Asserien, 75 miles (121 km.) east of Reval; (395d) at Ontika, about 95 miles (153 km.) east of Beval and 30 miles (48 km.) west of Narwa; and (395e) at Isenhof, 85 miles (137 km.) east of Reval; all fMickwitz, 1896, p. 192] in the Government of Esthonia, Russia. Obolus (Schmidtia) obtusus Mickwitz. Plate XIY, figures 3, 3a-c. Obolus {Schmidtia) obtusus Mickwitz, 1896, Mem. Acad. imp. sci. St.-P6tersbourg, 8th ser., vol. 4, No. 2, pp. 167-171, PI. II, figs. 23, 24, 33, and 34. (Described and discussed in German as a new species; see below for translation.) Obolus (Schmidtia) obtusus longus Mickwitz, 1896, idem, pp. 171-172, PL II, fig. 25. (Described and discussed in German as new variety. ) Obolus (Schmidtia) obtusus acutus Mickwitz, 1896, idem, pp. 172-173, PL II, fig. 26. (Described and discussed in German as a new variety. ) Obolus (Schmidtia) obtusus latus Mickwitz, 1896, idem, pp. 174-175, PL II, fig. 27. (Described and discussed in Ger- man as a new variet}^) Obolus (Schmidtia) obtusus minutus Mickwitz, 1896, idem, pp. 175-177, PL II, figs. 29 and 30. (Described and discussed in German as a new variety. ) Obolus (Schmidtia) obtusus ellipticus Mickwitz, 1896, idem, pp. 177-178, PL II, figs. 31 and 32. (Described and dis- cussed in German as a new variety.) Obolus (Schmidtia) obtusus extenuatus iliCKWiTz, 1896, idem, pp. 178-179, PL II, figs. 35 and 36. (Described and dis- cussed in German as a new variety.) Obolv^ obtusus (Mickwitz)?, Wi5ia>j, 1902, Bull. Geol. Inst. Univ. LTpsala, Bd. 6, pt. 1, No. 11, p. 63, PL III, fig. 12. (New locality mentioned in German.) Obolus obtusus (Mickwitz)?, Moberg and Segerbeeg, 1906, Medd. Iran Lunds Geol. Faltklubb, Ser. B, No. 2 (Aftryck ur K. Fysiografiska Siillskapets Handl., N. F., Bd. 17), p. 65. (Localitj' mentioned in Swedish.) Obolus obtusus (Mickwitz)?, Westergard, 1909, Medd. fran Lunds Geol. Faltklubb, Ser. B, No. 4 (Aftryck ur K. Fysiografiska Sallskapets Handl., N. F., Bd. 20), p. 57. (Locality mentioned in Swedish.) The original description by Micl^witz follows : This extraordinary species, whose principal characteristics consist in the peculiar character of the area which is predominantly prolonged, consists of a large number ot shells, which do not essentially deviate in outline and size. All of these forms are rare; of some of them only one was found; in consequence, their cospecificity could not be proven a Locality 395 is represented in the United States National Museum collections OBOLIDiE. 449 in all cases througli transitions. I was for a long time undecided as to whether I should refer all of these aberrant shells to one species. Nevertheless, the fact that deviations in a much greater measure are not extraordinary in other Obolas species, and, furthermore, the fear of multiplying the number of species without decisive reason, and, lastly, the correspondence of the different forms in the mentioned principal characters persuaded me to look upon the entire group as belonging to one species. The characteristic form was erected into a species and the others were subordinated to it as varieties. However, it is possible that with more complete material the one or the other variety will be removed from the species. At present this arrangement will make easy the general view of the forms. Diagnosis: Shells moderately large, flatly arched, drawn out lengthwise. Outline sub triangular. Tip of beak of the large shell somewhat protruded, obtuse-angled, externally obliquely truncated; small shell almost rectilinearly cut off. Borders of the beak of the large shell receding from the plane of shell borders, going over into the lateral borders with a roundish angle. Exterior surface of shell very smooth, strongly lustrous like varnish, concentric striae very fine. Growth lamellee marked by somewhat coarser grooves, commonly standing out at the anterior border like shingles. Area large, splanchnocoelic part broad, band-shaped; plemrocoelic part prolonged far into the lateral bor- ders. Plane of the area of the large shells broken in the peduncular groove, in the small shell depressed into broad grooves between the traces of the pseudo-area. Traces of the pseudo-area parallel in both shells very near to borders of area. Peduncular groove broad, flat, parallel bordered. Thickening of shell slight, inner configuration slightly pro- nounced. Central depression of large shell pestle-shaped, at times indefinitely flattened. Septa and corneous proc- esses receding very much. Median swelling of small shell strongly developed, divided by a sharp fmrow between the places of attachment of the anterior lateral muscles. Places of attachment of the muscles distinctly pronounced. Those of the outside lateral muscles of large shell circular, standing off from those of the central muscles and mostly separated by a roundish swelling. Observations: The few shells of this relatively rare species which are at hand in finest preservation do not allow some necessary characters of the visceral surface to be distinguished. Especially the impressions of the lateral vessels are withdrawn from observation, although just these characters, through their wonderful development and preserva- tionin some species of the subgenus Schmidtia (e. g., in 0. celatus and 0. crassus), make possible in the highest degree the study of the vascular system in Eichwald's genus. Yet, in spite of the incomplete characterization, 0. obtustis belongs to the best-defined species of the subgenus Schmidtia. The peculiarity shows itself for the first in the predominant prolongation and the slight arching, which find their numerical expression in the respective value of b : 1 and h : 1. These relative numbers are in 0. obhisus smaller than in all other species of the subgenus. * * * To the longitudinally extended form now comes the broad obtuse-angled tip of the beak, which gives the shells a subrectangular outline, and by which 0. obtusus is distinguished as well from all other species of the subgenus Schmidtia as from those of the other subgenera. The tip of the beak of a large shell loses its blunt form, and the rounded angle of the posterior border of the shell disappears, so that the outline becomes more broadly oval. In similar manner the small shell is changed. The corners of the blunted tip of the beak become round, and the rectilinearly truncate tip of the beak assumes a slightly convex form. Of less specific account than the form, but not less striking to the eye, is the more considerable size of the shells, which surpasses that of all other species of the subgenus Schmidtia, the average length of the large shell being 6.47 mm., while the corresponding valve of the next largest species (0. crassus) only attains 5.96 mm. These results refer to the species with the exception of the varieties; of the latter, 0. obtusus longus has a still more considerable length (7.7 mm.). The exterior surface of the shell of a specimen figured shows some short, radially placed, slight furrows on the central part of the sm'face; the furrows are lacking on the posterior borders. This striation can, however, only be looked upon as an occasional formation, for, even if slight furrows of the same kind can be noticed in another specimen,, they are entirely missing in all other shells examined. Isolated striae of this kind also occur in the other Schmidtias. The formation of the area is very aberrant. While this part of the shell is generally triangular in the other species, it assumes in 0. obtusus the form of a broad band, which hems the tip of the beak and is prolonged fai' into the borders of the shell. The splanchnocoelic part of the base of the area runs parallel to the borders of the beak and is, corre- sponding to the tip of the beak, angled in the peduncular furrow. In the small one it is rectilinear or slightly concave. The siu:face of the area of the large shell sinks, as in 0. celatus, only in a far stronger degree, from both sides toward the peduncular groove; besides this the whole surface of the area inclines obliquely toward the exterior, so that the borders of the beak recede from the surface of the border of the shell. The gap of the surface of the area in the pedun- cular groove is partly a consequence of the deficient thickening of the posterior part of the shell, which causes the lamellae of the area to appear as a mere covering of the hollow tip of the beak; yet it is partly brought about by a slight lateral compression of the tip of the beak, which is also indicated at the exterior sm-face of the shell through a slight roundish median edge perceptible in reflected light. In the small shell these conditions occm- in a similar manner, but stand out less distinctly. Especially characteristic for this species is the position of the traces of the pseudo-area, which run parallel to the median line of the shell and are very near the lateral borders of the area. In some the posterior part of these traces seems to bend toward the tip of the beak with a roundish angle. Yet in nature the traces of the pseudo-area run recti- linearly to the posterior border of the beak and the deflecting apparent prolongations of the same are only accidental examples of more strongly sculptured striae of the area. 62667°— VOL 51, pt 1—12 29 450 CMIBRIAN BRACHIOPODA. This position of the traces of the area, which is far removed from the peduncular groove, appears to point to the relative size of the embryonal shells — a conjecture to which the consideration of the broad, parallel-bordered peduncular groove of 0. obtusus has already led. In the small shell, the traces of the pseudo-area run exactly in the same man- ner, and inclose the flatly deepened splanchnocoelic part of the area between them, which allows a shallow, rather broad groove in the median line, opposite the peduncular groove of the large shell, to be perceptible by reflected light. The thickening of the shells is generally very slight, and therefore the configuration of the inner surface stands out but little. Nevertheless, predominant fluctuations occur also in this species. It is noteworthy that of all the formations which stand out from the surface of the shell, the median swelling of the small shell is the most given to variations, which often degenerate in a monstrous manner. * * * The heart-shaped groove is given to similar alterations of form as we have learned in 0. celatus, and may be partly dependent on the strength of the thickening * * *. The places of attachment of the muscles are in general distinctly pronounced, but not so sharply bordered as with the large forms of Eichwald's genus. Especially there are here also, as with 0. celatus, the large central spots of attach- ment of the large shell, only with difficulty decomposable into their constituent parts. As with the previous species, the outside lateral muscles are delimited from the central muscles and form, close to the principal vascular canals, isolated, shallow-pitted, excavated places of attachment. Of the principal vascular canals there can be distinguished on all the specimens at hand, in both shells, only the posterior parts; in the small shells, besides, as a rule, also the ends, curved around posteriorly and directed toward the places of attachment of the anterior lateral muscles. The first are very broad, flat, and divided by a median swelling, which often appears to be a prolongation of the lateral septa. The latter in no way deviates from the usual arrange- ment. Of the accessory vascular canals there can be observed only slight indications of the inwardly radiating canals, which show as somewhat lighter colored lines. Formation and locality.'' — Upper Cambrian: Obolus sandstone at the following localities: (395) At Joa, near Jegelecht, 12 miles {19.3 km.) east of Reval; and (395b) at Ilgast; both [Mickwitz, 1896, p. 171] in the Government of Esthonia, Russia. (321c [Wiman, 1902, p. 68]) Drift bowlder of Obolus sandstone. No. 17, on Fanton Island, parish of Borstil, Province of Stockholm, Sweden. WESTONIA Walcott,!> subgenus of OBOLtrS. Obolus (Westonia) Walcott, 1901, Proc. U. S. Nat. Mus., vol. 23, pp. 683 and 691. (Described on latter page, as below, as a new subgenus.) {Westonia) Walcott, Matthew, 1903, Geol. Survey Canada, Bept. Cambrian Rocks Cape Breton, pp. 205-206. (Copies original description, and discusses the form as a subgenus more allied to Lingulella than Obolus.) Lingulella Grabau and Shimek [not Salter], 1907, North American Index Fossils, vol. 1, p. 192. (Described as Lingulella, but both species that are referred to it belong with Obolus {Westonia).) Obolus { Westonia) Walcott, 1908, Smitihsonian Misc. Coll., vol. 53, No. 4, PI. XI, and pp. 142 and 144. (Classification of genus.) Ovate, with ventral valve slightly acuminate; area of ventral valve strongly defined and divided by a relatively large pedicle groove. Surface marked by concentric and radiating striae that are crossed by transverse, semi-imbricating, "ripple-embossed" lines. So far as known, the muscle scars and vascular markings are essentially the same as in Oholus. Type. — Lingula aurora Hah. Of the species referred to Westonia, Oholus {Westonia) aurora (Hall), 0. (TF.) ella (Hall and Whitfield), 0. {W.) euglyplius (Walcott), 0. {W.) chuarensis (Walcott), 0. (W.) stoneanus a Locality 395 is represented in the United States National Museum coilections. 6 The sjTionymy for this subgenus does not give a complete record of the various genera under which the species now included in Wcslonia were formerly placed; it gives only those references in which the genus is discussed or described. To complete the record the following mere generic references are listed: Lingula Hall [1861, p. 24]. Lingula Rogers [1861, p. .390; 1862, p. 4; 1863. pp. 12(i and 127: 1867, pp. 103 and 104]. Lingulella Hall [1873, p. 244]. LinguUpis Hall and Whitfield [1877, p. 232]. Lingula Barrande [1879b, Pis. CVI and CXI]. Lingulella Whitfield [1882, p. 344]. Lingulella Walcott [1886b, p. 97; 1891a, p. 607]. Lingulella Hall and Clarke [1892c, p. 58 and PI. II, figs. 9-11 and 12-13]. Lingula Sardeson [1896, p. 95]. Lingulepis Walcott [1897a, p. 404). Obolus (.Lingulella) Walcott [1898b, pp. 399, 402, and 413, and PI. XXVIII]. Lingulella Grabau [1900, p. 624). Lingulella? Matthew [1901a, p. 270]. ' Lingula Wiman [1902, p. 51]. Lingulellaf Wiman [1902, p. 52]. Obolus Matthew [19D2c, pp. 96 and 110]. Obolus (Westonia) Walcott [1902, p. 611]. Lingulella Weller [1903, p. 112]. Obolus (Westonia) Walcott [1905a, pp. 334, 335, 336, and 337). Lingulella Pack [1906, p. 295]. Lingulella (Westonia) Grabau and Shimer [1907, p. 193]. Obolus (Westonia) Walcott [1908d, pp. 67, 68, and 69]. OBOhlDM. 451 (Wliitfield), 0. (W.) rogersi (Walcott), 0. (WJ) lamellosus (B arr ancle), and 0. ( F.) escasoni (Matthew) all have transverse, irregular, elevated lines. In 0. ( W.) stoneanus and 0. ( W.) rogersi these lines have two or three sharp undulations near the median line, and in 0. ( W.) aurora many short and more or less irregular undulations occur on the entire central portion of the shell. Beyond the short, central undulations, more or less wave-like, long undulations extend to the sides of the valve, usually with a slight backward curvature toward the margin. Oiolus {Westonia) finlandensis Walcott, 0. (TF.) iottnicus (Wiman), and 0. (W.) wimani Walcott, of the Middle (possibly Lower) Cambrian sandstones of Sweden, differ in surface characters from the typical species of the genus. In these species the concentric lines and strise of growth are well marked, also radiating hnes that extend from the umbo irregularly toward the front and side margins of the shell. In addition there is a series of somewhat irregular strise or lines that terminate at right angles to the lateral margin, start in toward the center of the shell, and then curve backward so as to meet at the center, or merge apparently into the radiating strise (PL XLVIII, figs. 3 and 3a). These lines were apparently formed by the same agency (the front marghi of the mantle) that formed the various irregular, more or less trans- verse lines on the other species of the genus. The two other species from the sandstones of Sweden, 0. ( W.) dlandensis Walcott and 0. ( W.) halticus Walcott, appear to have the typical Westonia surface represented on 0. ( W.) ella, although it is exceedingly fine. The generic name was given in honor of Mr. T. C. Weston. Obolus (Westonia) alandensis Walcott. Plate XLVIII, figures 6, 6a. Lingulafsp. No. 2, Wiman, 1902, Bull. Geol. Inst. Univ. Upsala, vol. 6, pt. 1, No. 11, p. 52, PL II, fig. 39. (Locality given.) Lingulella ? sp. No. 3, Wiman, 1902, idem, p. 52, PL II, fig. 33. (Locality given. The specimen represented by fig. 33 is redrawn in this monograph, PL XLVIII, fig. 6.) Lingulella ? sp. No. 5, Wiman, 1902, idem, p. 52, PL II, fig. 35. (Locality given. The specimen represented by fig. 35 is redrawn in this monograph, PL XLVIII, fig. 6a.) Obolus {Westonia) alandensis Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 334. (Discussed essentially as below as a new species.) This species is characterized by its broad form when compared with Oiolus ( Westonia) bottnicus (Wiman), 0. ( W.) mmam Walcott, and 0. ( W.) halticusWalcott. Its surface is marked by fine concentric lines of growth, with very fine, threadlike, concentric strise between them. In strong, reflected light, almost microscopic, transverse, very irregular lines can be seen that give the surface somewhat the appearance of that of 0. (W.) ella (Hall and Whitfield). For reference to the geological horizon of bowlders on Eggegrund Island, similar to the ones containing this species, see description of 0. ( W.) bottnicus Walcott, p. 454. The species derives its specific name from its occurrence on Aland Island. Formation and locality. — Middle? Cambrian: (311] and 311k) Drift bowlders of bituminous sandstone, Nos. 28 and 29 [Wiman, 1902, p. 57], on Biludden, about 20 miles (32.2 km.) east of Gefle, Province of Gefleborg; and (311m) drift bowlder of bituminous sandstone, No. 1 [Wiman, 1902, p. 57], on Limon Island, about 12 miles (19.3 km.) northeast of Gefle, Province of Gefleborg; all in Sweden. (311y) Drift bowlder of rusty sandstone [Wiman, 1902, p. 57], at Ytternds, Slemmern, Aland Island, Finland, Russia. Obolus (Westonia) atjeoea (Hall). Plate XLVI, figures 1, la-h. Lingula aurora Hall, 1861, Kept. Supt. Geol. Survey Wisconsin, p. 24. Lingula aurora Hall, 1862, Kept. Geol. Survey Wisconsin, vol. 1, p. 21, fig. 4. (No text reference.) Lingula aurora Hall, 1863, Sixteenth Ann. Rept. New York State Cab. Nat. Hist., pp. 126-127, PL VI, figs. 4 and 5. (Described and discussed.) Lingula aurora Hall, 1867, Trans. Albany Inst., vol. 5, pp. 103-104, PL I, figs. 4 and 5. (Copy of preceding reference.) Lingulella aurora Hall, 1873, Twenty-third Ann. Rept. New York State Cab. Nat. Hist., pp. 244-245. (Merely changes generic reference.) 452 CAMBRIAN BEACHIOPODA. Lingidclla aurora (Hall), Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, PI. II, figs. 12 and 13. (No text reference.) Lingula aurora Hall, Sardeson, 1896, Bull. Minnesota Acad. Nat. Sci., vol. 4, No. 1, pt. 1, p. 95. (New localities mentioned.) Obolus {Westonia) aurora (Hall), AValcott, 1901, Proc. U. S. Nat. Mus., vol. 23, p. 691. (Merely changes generic reference.) Lingulella aurora (Hall), Grabau and Shimee, 1907, North American Index Fossils, vol. 1, p. 193. (Described.) General form broadly ovate, with the dorsal valve almost subcircular, except for the gentle slope of the cardinal margins toward the low obtuse beak. The beak of the ventral valve is almost invariably broken off, as shown in Plate XL VI, figures la to Id. If the cardinal slopes are restored, as in figure Ic, the form of the beak is rather obtuse. Original convexity unknown, as aU of the large number of specimens in the collection are compressed and often fiattened on the surface of the shaly sandstone. It appears to have been moderate like that of Lingulella ampla (Owen) and Oholus (Westonia) stoneanus (Whitfield). The shell appears to have been built up of a tliin outer layer and thin lamellose inner la3i-ers. On some of the casts of the valves the character of both the inner and outer surface markings is shown. The outer surface of the shell is marked by concentric striae and lines of growth and a complex system of lamellose striae. The latter are almost directly transverse near the sides of the shell and curve slightly backward over the central portion, where they have a sharp zigzag character that is highly characteristic (PI. XL VI, figs. Ig and Ih). When the outer surface of the shell is exfohated the surface is marked by concentric lines and striae and fine radiating striae (figs. 1 and lb). This latter surface is probably caused by the markings of the inner surface of the shell and the inner surface of the outer layer or lamella, as is seen so frequently in the shell of Lingulella acutangula (Roemer) (PI. XVII) and Dicellomus folitus (Hall) (PL LII). The appearance of several specimens leads to the conclusion that the interior surface was more or less punctate. It frequently happens that the outer surface of the shell is worn nearly smooth, the only remaining traces of the beautiful surface ornamentation being toward the beak, or a spot here and there protected by a strong raised line of growth. This is one of the largest shells of the genus. A ventral valve from Mazomanie is 21 mm. long, with a maximum width of 17 mm., and an associated dorsal valve is 17.5 mm. long and 17 mm. in width. The cardinal area is well defined in both valves. In the ventral valve it is divided at the center by a strong pedicle groove and toward its margins by narrow, clearly defined flexure fines. The striae of growth cross the area parallel with its base (PI. XL VI, fig. Ic). The area formed a thin shelf between the pedicle groove and the lateral margms, and the undercut extended back beneath the area, but how far can not be determined, as the cast of it is broken away in the specimens in the collection. The area of the dorsal valve is short as compared with that of the ventral valve. It extends weU out on the cardinal slopes, and has a very faintly indicated flexure line near the lateral margin. The cast of the visceral cavity (v) is partly shown in figure la. There is a peculiar apron-hke area that extends forward from the flattened cast of the pedicle groove (PL XL VI, figs. Ib-d) that probably represents a broad groove that existed in the interior of the shell back of the visceral cavity. No clearly defined muscle scars have been observed. Ohservations. — The surface ornamentation is very characteristic, and is of the same general type as that of Oholus (Westonia) ella. (Compare PL XLVI, fig. Ih, with PL XLVII, fig. lo.) The outline of the valves is somewhat like that of Lingulella am^la (Owen) (PL XXVIII). It differs in bemg wider m proportion to the length. As pointed out by HaU, Oholus (Westonia) aurora is from the upper beds at Mazomanie and Lingulella ampla from the lower beds at Trempealeau. - Formation and locautt.— Upper Cambrian: (S85x)a In the upper beds of the "St. Croix sandstone," near Mazo- manie, Dane County; (85s) "St. Croix sandstone," at Prairie du Sac, Sauk County; (78, 78c, and 78s) "St. Croix sand- stone" at Osceola, Polk County; (79) "St. Croix sandstone," in bluff near Hudson, St. Croix County; (86) "St. o S85x is the type locality, though the specimens in the United States National Museum collections to which that number is assigned were collected much later than the type specimens. The species also occurs in Localities 3281 and 328p. OBOLID^. 453 Croix sandstone," at Van Ness quarry, Gibraltar Bluff, Lodi, Columbia County; and (328b) St. Lawrence formation [Sardeson, 1896, p. 95], at Osceola, Polk County; all in Wisconsin. (339a) St. Lawrence formation [Sardeson, 1896, p. 95], at Otisville, Washington County; and (97 and 339c) Reeds Landing, foot of Lake Pepin, Wabasha County; both in Minnesota. Obolus (Westonia) balticus Walcott. Plate XLVIII, figures 7, 7a-b. Idngulella? sp. No. 4, Wiman, 1902, Bull. Geol. Inst. Univ. Upsala, vol. 6, pt. 1, No. 11, p. 52, PI. II, figs. 37 and 38. (Locality given. The specimens represented by figs. 37 and 38 are redrawn in this monograph, PL XLVIII, figs. 7a and 7b, respectively.) lAngulella? sp. No. 6, Wiman, 1902, idem, p. 52, PI. II, fig. 34. (Locality given. The specimen represented by fig. 34 is redrawn in this monograph, PI. XLVIII, fig. 7.) Obolus (Westonia) hallica Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 334. (Characterized as below as a new species.) This species is characterized by its elongate form, with the sides of the dorsal valves regu- larly rounded from the back to the rounded frontal margin. The dorsal valves are also more regularly and strongly convex than in other species occurring in the Cambrian sandstones of Sweden. The outer surface is marked by concentric and radiating striae, crossed obliquety by very fine, irregidar transverse striae. The latter are only to be seen with a strong magnifier and favorable light. For reference to the geologic horizon of bowlders on Eggegrund Island, similar to the ones containing this species, see description of Oholus ( Westonia) hottnicus, page 454. The species derives its name from its occurrence in the North Baltic region. Formation and locality. — Middle? Cambrian: (311h) Drift bowlder of bituviinous sandstone, No. 26 [Wiman, 1902, p. 57], on Biludden, about 20 miles {32. 2 1cm.) east ofGefle; and (311o) drift bowlder of bituminous sandstone. No. 1 [Wiman, 1902, p. 57], on Skalstenarne Island, just west of Eggegrund Island, about 25 miles (40 km.) east-northeast of Gefle; both in the Province of Gefleborg, Sweden. (311t) Drift bowlder of mottled calcareous sandstone [Wiman, 1902, p. 57], at Ofverby, paiish of Jomala, Aland Island, Finland, Russia. Obolus (Westonia) blackweldeei Walcott. Plate XXXIX, figures 10, lOa-c. Obolus (Westonia) bladcwelderi Walcott, 1905, Proc. LT. S. Nat. Mus., vol. 28, p. 335. (Described and discussed as below as a new species.) General form elongate, with the width about one-half the length; front margin broadly rounded; sides slightly arched up to the lateral slopes, which are quite straight in the ventral valve and curved toward the rounded posterior end of the dorsal valve ; the beak of the ventral valve is pointed and marginal. The convexity of the valves is moderate, that of the dorsal apparently being the greater. Surface marked by concentric stride and lines of growth which are crossed by irregular, fine, imbricating, more or less transverse lines; the transverse lines trend slightly backward toward the sides of the valves. A dorsal valve 8 mm. in length has a width of 5 mm. Observations. — Nothing is known of the interior of the valves. When the shell is broken from the limestone, the outer surface usually adheres to the matrix. The best exteriors are those of shells on the surface of the layers. Of the known species of Westonia, 0. (W.) wimani Walcott, and 0. ( TF.) halticus Walcott are most nearly related to 0. ( W.) llackweUeri. The latter is a larger shell and also less narrow proportionally where the gently arching sides pass into the posterolateral slopes. The specific name is given for Prof. Eliot Blackwelder, of the University of Wisconsin, who collected the specimens. Formation and localitt.— Middle Cambrian: (CI and C2) Lower shale member of the Kiulung group [Black- welder, 1907a, pp. 37 and 40 (part of the 3d list of fossils), and fig. 10 (bed 4), p. 38], 2 miles (3.2 km.) south of Yenchuang; and (C6) thin slobby limestone in the upper shale member of the Kiulung group [Blackwelder, 1907a, pp. 37 and 41 (2d list of fossils), and fig. 10 (bed 12), p. 38\, 2.5 miles (4 hm.) southwest of Yenchuang; both in the Sintai district, Shantung, China. 454 . CAMBRIAN BRACHIOPODA. Obolus (Westonia) bottnicus (Wiman), Plate XLVIII, figures 4, 4a-c. Lingula botinica Wiman, 1902, Bull. Geol. Inst. Univ. Upsala, vol. 6, pt. 1, No. 11, p. 51, PI. II, figs. 40-44. (Charac- terized and discussed in German as a new species. The specimens represented by figs. 41, 42, 4.3, and 44 are redra-nm in this monograph, PI. XLVIII, figs. 4, 4a, 4b, and 4c, respectively.) Obolus (Westonia) bottnica (Wiman), Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 335-336. (Characterized and discussed as below.) The description of Obolus (Westonia) foilaridensis Walcott so closely applies to this species that it is only necessary to point out the difference between the two and to compare the figures illustrating them. The surface of Oholus (Westonia) hottnicus has the same concentric and radiating lines with the irregular, transverse lines terminating at right angles to the margins, curving inward and backward in such a manner as obliquely to cross the radiating lines that extend from the umbo forward to the anterior and anterolateral margins. The central scars of the dorsal valve are much farther forward in 0. ( W.) hottnicus. Wiman [1902, p. 51] refers this species to the Olenellus sandstone series. The bowlder containing it also carried Aparcliites? anderssoni, Hipponicharion matihewi, Acrotreta egge- grundensis, Kutorginaf, Torellella Isevigata, and fragments referred to Olenellus. This fauna is essentially Middle Cambrian in its facies and unless the fragments referred to Olenellus are indisputably of that genus, I am inclined to refer the bowlder and its contained fossils to the Middle Cambrian. The fact that Obolus (Westonia) hottnicus is nearly identical with 0. (W.) finlandensis of the Middle Cambrian of Finland also points to the Mddle Cambrian age of the fauna. The specific name is derived from the Swedish form of the word Bothnia. Formation and locality. — Middle? Cambrian: (311) Drift bowlder of coarse-grained, somewhat friable, glauconitic sandstone, No. 3 [Wiman, 1902, p. 57], on Eggegrund Island, about 25 miles (40 Im.) east-northeast of Gefle, Province of Geflehorg, Sweden. Specimens which were doubtfully referred to this species by Wiman occur at the following locality : Middle? Cambrian: (311e) Drift bowlder of rusty sandstone [Wiman, 1902, p. 57], south of Lumparn, parish of Jomala, Aland Island, Finland, Russia. Obolus (Westonia) chuarensis (Walcott). Plate XXA', figures 2, 2a-e. OboltLS (Lingulella) chuarensis Walcott, 1898, Proc. U. S. Nat. Mus., vol. 21, p. 399. (Described and discussed essentially as below as a new species.) Obolv^ ( Westonia) chuarensis Walcott, 1901, Proc. U. S. Nat. Mus., vol. 23, p. 691. (Merely changes generic reference.) General form broadly ovate, almost subquadrate, with the ventral valve obtusely acuminate, and the dorsal valve rounded subquadrate, the posterior margin being broadly obtuse; convexity moderate, increasing somewhat in the older shells. Surface of shell marked by rather strong, concentric lines and strise of growth and very fine, more or less transverse and irregular, appar- ently imbricating strise such as ornament the surface of Obolus (Westonia) ella (HaU and Wliit- field) and 0. (W.) euglyphus (Walcott). Fine radiating strise also appear under a strong magnifying glass. When the outer surface is exfohated the inner layers of the shell show traces of radiating strise. The inner surface is marked by pits or punctse, arranged in more or less irregular concentric lines; also fine radiating strife. The shell is strong and formed of a thin outer layer and several inner layers or lamellse., those near the outer margm being arranged obliquely to the outer surface. The only traces of the interior markings are those on the casts of the dorsal valve. These show a short and rather broad area, strong vascular sinuses, and traces of the anterior lateral muscle scars. OBOLID.E. 455 Observations. — The character of the surface ornamentation and subquadrate form of the dorsal valve lead to a comiiarison with 0. ( W.) ella (Hall and "Wliitfield) (PI. XLYII) of the Rocky Mountain fauna. The species differs from the latter in having a thicker, stronger shell, relatively shorter in proportion to its length. The surface is also of the same type as that of 0. (TF.) euglypTius (Walcott) (PI. XL VIII), which occurs at the same horizon in the upper portion of the "Tonto" sandstone but not associated with it. It differs from 0. (IF.) euglypJius in being much shorter and broader in proportion to its length. The species derives its name from its occurrence in the Chuar Vallej^, Grand Canyon of the Colorado, Arizona. Formation and locality. — Middle Cambrian: (74) Sandstone about 300 feet (91.4 m.) above the base of the Tonto group at the head of Nunkoweap Valley; (74b) sandstone about 1,000 feet (305 m.) above the base of the Tonto group, at the head of Nunkoweap Valley; (73) sandstones of the Tonto group in Kwagunt Valley; and (73a) " Tonto" sandstone, in Chuar Valley; all in the Grand Canyon of the Colorado, Arizona. Obolus (Westonia) daetoni (Walcott). Text figures 40A-C. Oholus (Westonia) dartoni Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, p. 67, PL VII, fig. 14. (Discussed as below as a new species. Fig. 14 is reproduced below, fig. 40A.) This species has the general form and convexitj' of Obolus ( ^Yeston^a) eughjphus (Walcott) (PI. XL VIII, figs. 1, la-e). It differs in the dorsal valve being narrower posterior^. The surface of the two species differs very much, that of 0. ( W.) dartoni being of the 0. (W.) eUa (Hall and Wliitfield) type (PI. XLVII, fig. lo) and not like that of 0. ( TV.) euglyphus (PI. XLVIII, fig. If). From 0. (TF.) ella this species differs in being more elongate in outline and in having the surface more clearly marked by the crossing of the mmute ridges. These ridges are slightly irregular and curve from near the umbo obliqueh^ across the shell toward the lateral and fi-ont margins so as to form a pattern much like that shown on the front portion of Plate XLVII, figure le. Some portions of the surface recall that of the central portions of Plate XLVI, figure Ih. The largest ventral valve has an indicated length of 12 to 15 mm. ; width, 9 mm. The specific name was given for Mr. N. H. Darton, of the United States Geological Survey, who collected the specimens. Formation and locality. — Middle Cambrian: (302o) Sandstones just above the granite, west of Garfield Peak, 50 miles (80.5 km.) west of Casper, Natrona County, Wyoming. Obolus (Westonia) ella (Hall and Whitfield.) Plate XXXIII, figures 3, 3a-c; Plate XLVII, figures 1, la-p. Lingulepis ella Hall and Whitfield, 1877, U. S. Geol. Expl. 40th Par., vol. 4, p. 232, PI. I, fig. 8. (Described and discussed as a new species. The specimen represented by fig. 8 is redrawn in this monograph, PI. XLVII, fig. lb.) Lingulella ella (Hall and \Vhitfield), Walcott (in part), 1886, Bull. U. S. Geol. Survey No. 30, pp. 97-98, PI. VII, fig. 2; PI. VIII, figs. 4, 4a, 4d, and 4e (not figs. 4b and 4c, now referred to Lingulella dubia). (Copies original description and describes and discusses species. Fig. 4. is redrawn from the specimen represented in fig. 8 of the preceding reference. The specimens represented by figs. 2 and 4 are redrawn in this monograph, PL XLVII, figs. Im and lb, respectively.) Lingulella ella (Hall and Whitfield), Walcott (in part), 1891, Tenth Ann. Rept. U. S. Geol. Survey, p. 607, PL LXVII, figs. 2, 2a-b, and 2e (not figs. 2c and 2d, now referred to Lingulella dubia). (Horizons mentioned. Figs. 2, 2a-b, and 2e are copied from figs. 2, 4a, 4, and 4e, respectively, of the preceding reference.) A B C Figure iO.—Obotus (Weslonia) dartoni Walcott. A, Ventral valve, worn smooth bj' beach action (U. S. Nat. Mus. Cat. No. 5t6S3a). B, Dorsal valve, worn smooth (U. S. Nat. Mus. Cat. No. 51C83b). C, Enlargement ol the surface, X 10 (U. S. Nat. Mus. Cat. No. 51683c). The specimens represented are from Locality 302o, Middle Cambrian sandstones near Garfield Peak, Wyoming. Figure 40A is copied from Walcott H908d, n. VII, fig. 14); it represents the type specimen. 456 CAjMBRIAN brachiopoda. Lingidclla eUa (Hall and ^\^litfield), Hall and Clarke (in part), 1892, Nat. Hist. New York, Paleontology, vol. S, pt. 1, p. 58, figs. 19 and 21 (not fig. 20, now referred to Lingulella dubia). (Species discussed in the text. Figs. 19 and 21 are copied from Walcott, ISSCb, PI. VII, fig. 2, and PI. VIII, fig. 4a.) Lingidepis ella Hall and ^^^litfield, Walcott, 1897, Am. Jour. Sci., 4th ser., vol. 3, p. 404. (Merely changes generic reference.) Obolus {Lingulella) ella (Hall and \\Tiitfield), Walcott, 1898, Proc. U. S. Nat. Mus., vol. 21, PI. XXVIII, figs. 5-8. (No text reference. The specimens represented by figs. 5-8 are redrawn in this monograph, PI. XLVII, figs. Ig, Ik, Id, and li, respectively.) Obolus (Westonia) ella (Hall and ^^Tiitfield), Walcott, 1901, Proc. U. S. Nat. Mus., vol. 23, p. 691. (Merely changes generic reference.) Obolm ella (Hall and Miitfield), Matthew, 1902, Trans. Roy. Soc. Canada for 1902, 2d ser., vol. 8, sec. 4, No. 3, pp. 96 and 110, PI. I, figs. 9a-b. (Discussed on both pages.) Lingulella ella (Hall and AATiitfield), Pack, 1906, Jour. Geol., vol. 14, No. 4, p. 295, PL I, figs. 2 and 2a. (Mentioned, and new localities given.) Lingulella (Westoiiia) ella (Hall and ^^^■litfi■eld), Grabau and Shimer, 1907, North American Index Fossils, vol. 1, p. 193, figs. 229a-b. (Described. Figs. 229a-b are copied from Walcott [1886b, PL VIII, figs. 4 and 4a, respectively].) General form broad ovate, with the dorsal valve subquadrate or rounded quadrate and the ventral valve obtusely acuminate; valves moderatel}' convex, so far as can be determined from the crushed and flattened specimens from the shales of Utah and Nevada. Surface of the shell marked bj^ concentric strise and lines of growth and, on the type specimen, by very fine, irregular, lamellose, more or less transverse striae and fine radiating lines; the surface is much like that of 0. ( W.) euglyphus (Walcott) (PI. XL VIII) ; fine, clearly defined radiating lines occur on the inner layer of the shell of partly exfoliated specimens. The cast of the inner surface of the shell shows papillae that filled punctte in the shell; they are rather large and are arranged in the central portion of the shell in concentric lines, much as in Lingulella davisi. The shell is strong and rather thick in old shells. It is made up of a tliin outer layer and several inner layers or lamellfe that are well shown in the figure of the t3'pe specimen (PI. XLVII, fig. lb). The largest ventral valve thus far examined has a length of 16 mm. and a width of 13 mm. A dorsal valve is 13 mm. long by 12.5 mm. in width. The area of the ventral valve is of the same type as that of 0. ( W.) aurora (Hall) (PI. XL VI) and Lingulella ampla (Owen) (PI. XXVIII) . The flexure line is nearer the pedicle fur- row than in Lingulella perattenuata (Whitfield) (PI. XXI), L. acutangula (Roemer) (PI. XVII), Lingulella ampla, and Oholus ( AYestonia) aurora, which results in a wider outer lateral space on the area (PL XLVII, fig. Ic (a')). The pedicle furrow is strong and deeply rounded, and in one specimen referred to this species (PI. XLVII, figs. Id and Ig) the cast of the base of the undercut between the area and the outer shell is clearly shown on each side of the pedicle groove. The area of the dorsal valve is low and broad; the flexure lines cross it so as to form a broad, slightly elevated space in the cast corresponding to a broad, shallow furrow in the shell (PI. XLVII, fig. li). The striae of growth cross the area parallel with its base, both in the ventral and dorsal valves. The cast of the interior of the ventral valve shows the visceral cavity (PL XLVII, figs. Ic, Id, and Ig) and the median septum of the dorsal valve is seen in figures li and Ik. The muscle scars are not distinctly shown on the ventral valve. In the dorsal valve the central scars (h) are preserved in specimens from Nevada (fig. li) and Montana (figs. 1 and Ik), and the anterior laterals in Plate XLVII, figures Ik and 1 1. The remains of markings made by the vascular system are limited to the main or trunk sinuses of the two valves, and a jjortion of the parietal scar (]3s) is seen on one specimen of the ventral valve (PL XLVII, fig. Ig). Observation fi. — The type specimen of this species is a somewhat crashed dorsal valve that fortunately preserves the outer surface and much of the shell. Near the tj^pe locality, and in the same band of slaty shales, were found a number of specimens, including a series of j'oung shells. Two of the larger shells are shown by Plate XLVII, figures 1 and la, and two of the OBOLIDiE. 457 young by figures le and If. . The shells found near Helena, Montana, commonly occur as casts in a siliceous shale and have the form of and appear to be specifically identical with the species in the Wasatch and Oquirrh mountains. A few specimens preserve the shell and show it to be thick and stronglj'- laminated toward the front. The form from the Bighorn Mountains of Wyoming appears to be identical with this species, except that the surface ornamentation is coarser and much more distmctly outlined by the zigzag, irregular, transverse striae. The strength of the stride and the size of the more or less rhombic interspaces range from near those of 0. (TF.) dla to more than double their size, the increase in the size of the interspaces being made more prominent by the deposition of what appears to be chalcedony on the outer surface or a replacement of the shell by chalcedony. The form of the valves and the position of the central and anterior lateral muscle scars in the dorsal valve are essentially the same as in 0. ( TF.) eUa. On Gordon Creek in Montana this species occurs in association with the Albertella Jielena fauna [Walcott, 1908f, p. 202], which is referred to the highest zone of the Lower Cambrian. Four small ventral valves were found that have the form and surface characteristic of Obolus (Westonia) eUa. Obolus ( Westonia) ella has a wide geographic distribution in the Cordilleran and southern Apijalachian regions. It also has a vertical range from the summit of the Lower Cambrian in Montana and British Columbia to 250 feet up in the Upper Cambrian. Formation and locality. — ^Tipper Cambrian : (4y and 54t) Limestone of the St. Charles formation [Walcott, 1908a, p. 6], about 250 feet (76 m.) above the Middle Cambrian on the north side of Twomile Canyon, near its mouth, 2 miles (3.2 km.) southeast of Malade, Oneida County, Idaho. (54e) About 200 feet (61 m.) above the Middle Cambrian and 1,025 feet (212.4 m.) below the top of the Upper Cambrian in limestones forming 3 of the St. Charles formation [Walcott, I908f, p. 193], in Blacksmith Fork Canyon, about 10 miles (16.1 km.) east of Hyrum, Cache County, Utah. Middle Cambrian: (57g) About 1,700 feet (518 m.) above the Lower Cambrian and 3,250 feet (991 m.) below the Upper Cambrian, in the siliceous shales forming 2d of the Stephen formation [Walcott, 1908f, p. 211], on Mount Bos- worth, north of the Canadian Pacific Railway between Hector and Stephen, on the Continental Divide, between British Columbia and Alberta, Canada. (5f) Limestone interbedded in the Wolsey shale [Weed, 1900, p. 285], in Meagher County, on the road to Wolsey, about 4 miles (6.4 km.) south of the divide at the head of Sawmill Creek, and 11 miles (17.7 km.) south of Neihart, Little Belt Mountains quadrangle (U. S. Geol. Survey), Cascade County; (340a) shales near Helena, Lewis and Clark County; (302s) dark siliceous shale in a quarry in Last Chance Gulch, south slope of Mount Helena, 1.5 miles (2.4 km.) south of Helena, Lewis and Clark County; (4u) shales in the Gallatin formation of Peale [1893, PI. IV], northwest side of canyon 0.5 mile (0.8 km.) south of Helena, Lewis and Clark County; (9m) shale 4 miles (6.4 km.) above Walker's ranch, on North Fork of Dearborn River, in the eastern part of the Lewis and Clark National Forest, Lewis and Clark County; (4ii') limestone about 310 feet (94.5 m.) above the unconformable base of the Cambrian and 185 feet (56.4 m.) above the top of the quartzitic sandstones in a shale which corresponds in stratigraphic position to the upper part of shale No. 6 of the Dearborn River section [Walcott, 1908f, p. 202], on the ridge between Gordon and Youngs creeks, about halfway between Gordon Mountain and Cardinal Peak, Ovando quadrangle (U. S. Geol. Sm:vey), Powell County; (4k) about 725 feet (221 m.) above the base of the Cambrian in the shales of the Gallatin formation of Peale [1893, PL IV], on the north side of West Gallatin (Gallatin) River, northeast of Logan, Threeforks quadrangle (U. S. Geol. Sm-vey), Gallatin County; and (4g) about 325 feet (99.1 m.) above the base of the Cambrian in the Flathead shales of Peale [1893, p. 21], 1 mile (1.6 km.) north of the junction of East Gallatin and West Gallatin (Gallatin) rivers, 4 miles (6.4 km.) east-northeast of Logan, Threeforks quadrangle (U. S. Geol. Survey), Gallatin County; all in Montana. (5h and 55d) About 2,000 feet (609.6 m.) above the Cambrian quartzitic beds in a shale which is probably to be referred to the Bloomington formation [Walcott, 1908a, p. 7], on the south side of Twomile Canyon, near its mouth, 2 miles (3.2 km.) southeast of Malade, Oneida County; and (55c) Spence shale member of the Ute limestone [Walcott, 1908a, p. 8], about 50 feet (15.2 m.) above the Brigham quartzite and 2,755 feet (839.7 m.) below the Upper Cambrian, in a ravine running up into Danish Flat fi'om Mill Canyon, about 6 miles (9.6 km.) west-southwest of Liberty and 15 miles (24.2 km.) west of Montpelier, Bear Lake County; both in Idaho. (171a) Sandstone in Big Goose Creek Canyon, in the Bighorn Mountains, west of Sheridan, Sheridan County; and (4n) limestone about 325 feet (99.1 m.) above the unconformable base of the Cambrian in divide at the head of Jackson Creek (locally known as Sheep Creek), a creek flowing into Jackson Lake about 0.5 mile (0.8 km.) south of its northwestern corner, Teton Mountains, Grand Teton quadrangle (U. S. Geol. Sm'vey), Uinta County; both in Wyoming. (3g) Shales on the river bank 250 feet (76.2 m.) above the west end of the Denver and Rio Grande Railroad tunnel, Glenwood Springs, Garfield County, Colorado. 458 CAMBRIAN BRACHIOPODA. (329c) In Weber Canyon, about 2.5 miles (4 km.) northeast of Peterson, Morgan County; (30p) about 125 feet (3S m.) above the Cambrian quartzitic sandstones, on the north side of Ogden Canyon, about 1 mile (1.6 km.) above its mouth, east of Ogden, Weber County; and (30a) shale on north side of Big Cottonwood Canyon, 1 mile (1.6 km.) below jVrn-enta, Wasatch Range, southeast of Salt Lake City, Salt Lake County; all in Utah. (32y) Shales about 175 feet (53.3 m.) above the Brigham quartzite [W'alcott, 1908a, p. 8], in the Wasatch Moim- tains 1 mile (1.6 km.) northwest of Geneva (Copenhagen), east of Brigham; (32p and 55e) Spence shale member of the Ute limestone, about 100 feet (30.5 m.) above the Brigham quartzite [Walcott, 1908f, p. 197], in Wasatch Canyon, east of Lakeview Ranch, 5 miles (S km.) north of Brigham; and (329) green shales in a canyon about 7 miles {11.2 Jem.) north of Brigham {near the village of " Calls Fort" [Hague, 1S77, p. 405\); all in Boxelder County, Utah. (31e and 54a) About 750 feet (228.6 m.) above the Brigham quartzite and 3,440 feet (1,048.5 m.) below the Upper Cambrian, in the shales forming 2a of the Ute limestone [Walcott, 190Sf, p. 196], in Blacksmith Fork Canyon, about 10 miles (16.1 km.) east of Hyrum; (32d) shales about 150 feet (45.7 m.) above the Brigham quartzite [Walcott, 1908a, p. S], on the east side of the south fork of Paradise Dry Canyon (locally known as East Fork), east of Paradise; and (31z and 55t) about 350 feet (106.7 m.) above the Brigham quartzite, in the Ute limestone [Walcott, 1908a, p. 7], on west side of road 0.5 mile (0.8 km.) above the forks, Paradise Dry Canyon, east of Paradise; all east of Cache Valley, Cache County, LTtah. (32o) Shale about 325 feet (99 m.) above the Cambrian quartzitic sandstones, 2 miles (3.2 km.) southeast of Muskrat Spring, on the northwest face of Grantsville Peak, Stansbury Range; (3d) concretionary limestone about 100 feet (30.5 m. ) above the Cambrian quartzitic sandstones, at Ophir, Oquirrh Range; (329e) shales in East Canyon, above Ophir, Oquirrh Rano-e; (3c) shales about 75 feet (22.9 m.) above the Cambrian quartzitic sandstones, at Ophir, Oquirrh Rano-e; and (321i and 32z) shales in a canyon on the west side of the Simpson Range, 4 miles (6.4 km.) south of Simpson Spring, about 20 miles (32.2 km.) west-southwest of Vernon; all in Tooele County, Utah. (30d) About 1,020 feet (310.9 m.) above the Lower Cambrian and 3,400 feet (1,036.3 m.) below the Upper Cambrian in the limestone forming le of the Swasey formation [Walcott, 1908f, p. 182], at the head of Dome Canyon; and (31s) 490 feet (149.4 m.) above the Lower Cambrian and 3,925 feet (1,196.3 m.) below the Upper Cambrian in the pinkish argillaceous shale forming Id of the Howell formation [Walcott, 190Sf, p. 182], south side of Dome Canyon about 1 mile (1.6 km.) below the divide; both about 3 miles (4.8 km.) west-southwest of Antelope Springs, House Range [Walcott, 1908f, PI. XIII], Millard County, Utah. (31) Shales on the dump of the Chisholm mine; (333b [Pack, 1906, p. 295]) shales on the dump of the Half-moon mine; (333a [Pack, J.906, p. 295]) shales on the dump of the Himon mine; (333 [Pack, 1906, p. 295]) shales on the dump of the Abe Lincoln mine; (7k) shales in the dumps of the Half- moon and Chisholm mines, southwest slope of Ely Moun- tains; and (31u) shales on the west slope of the spur facing the main part of the Highland Range; all about 3 miles (4.8 km.) northwest of Pioche, Lincoln County, Nevada. (90) Conasauga ("Coosa") shale, on Edwards farm, near Craigs Mountain, about 10 miles (16.1 km.) southeast of Center, Cherokee County; and (141a) limestone 0.25 mile (0.4 km.) west of the hotel at Montevallo, Shelby County; both in Alabama. (14a) Sandstone of the Rome formation along First Creek Gap, 4 miles (6.4 km.) north-northeast of Knoxville [Keith, 1905, areal geology sheet], Knox County, Tennessee. Lower Cambrian: (4v) About 200 feet (61 m.) above the unconformable base of the Cambrian and 75 feet (22.9 m.) above the top of the quartzitic sandstones in a shale which corresponds in stratigraphic position to shale No. 6 of the Dearborn River section [W^alcott, 1908f, p. 202], on Gordon Creek, 6 miles (9.6 km.) from South Fork of Flathead River, Ovando quadrangle (U. S. Geol. Survey), Powell County, Montana. (33i) About 100 feet (30.5 m.) above the Prospect Mountain quartzite in the shales of the Pioche formation [Wal- cott, 1908f, p. 171], 0.25 mile (0.4 km.) below the Maxfield mine, Big Cottonwood Canyon, west front of the Wasatch Mountains, southeast of Salt Lake City, Salt Lake County, Utah. (30) Eight miles (12.8 km.) north of Bennetts Spring, on the west slope of the Highland Range, Lincoln County, Nevada. Specimens that are somewhat doubtfully referred to Oholus (Westonia) eUa occur at the following localities: Middle Cambrian: (57y) About 1,900 feet (579 m.) above the Lower Cambrian and 3,050 feet (930 m.) below the Upper Cambrian, in the siliceous shales forming 2a of the Stephen formation [Walcott, 1908f, p. 211], on Mount Bos- worth, north of the Canadian Pacific Railway between Hector and Stephen, on the Continental Divide between British Columbia and Alberta, Canada. (31d and 541) About 500 feet (152.4 m.) above the Brigham quartzite and 3,700 feet (1,127.8 m.) below the Upper Cambrian, in the Spence shale member of the Ute limestone [Walcott, 1908f, p. 197], in Blacksmith Fork Canyon, about 10 miles (16.1 km.) east of Hyrum, Cache County; (32n) shales about 725 feet (221 m.) above the Brigham quartzite [W'alcott, 1908a, p. 8], in the Wasatch Mountains, 1 mile (1.6 km.) northwest of Geneva (Copenhagen), east of Brigham, Boxelder County; and (lis) shales just above Simpson Spring, about 20 miles (32.2 km.) west-southwest of Vernon, on the stage road from Vernon to Fish Springs, Tooele County; all in Utah. OBOLID^. 459 ObOLUS (WeSTONIA) ELLA ONAQUIENSIS Walcott. Plate XLIX, figures 6, 6a. Obolus (Westonia) ella onaquiensis Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, pp. 67-68. (Discussed as below as a new variety.) This varietj' is represented bj' a number of more or less imperfect specimens that at first sight might be phxced with Obolus ( Westonia) ella (Hall and Whitfield), but the character of the surface clearly distinguishes the two forms. In typical forms of 0. (W.) ella the transverse striae are more regular, while in this variety they are in the form of sharp, finely zigzag, trans- verse strife much like the shells of the species from the Bighorn Mountains. This surface is formed by the interruption of very fine sharp ridges that curve from the umbo outward toward the sides and front of the shell like engine-turned strise on a watch case. This form derives its varietal name from its occurrence in the Onaqui Range of Utah. Formation and LOCALrrY. — Middle Cambrian: (33f) Shales about 400 feet (122 m.) above the Cambrian quartzitic sandstones, on the western slope of the high peak southwest of Lookout Pass, Onaqui Range, west of Vernon, Tooele County, Utah. Obolus (Westonia) elongatus Walcott. Plate LXIII, figures 8, 8a-d. Obolus (Westonia) elongatus Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, p. 68, PI. VII, fig. 12. (Described and discussed as below as a new species. Fig. 12 is copied in this monograph, PI. LXIII, fig. 8a.) General form elongate oval, with the ventral valve acuminate and the dorsal valve elongate oval. Convexity unknown, as the shells are all flattened by compression. The outer surface is marked by fine concentric lines of growth crossed by a series of finely denticulated, imbricating lines that start on each cardinal slope and extend obliquely forward across the median line, and then curve out toward the sides of the shell; minute rhomboidal ■spaces are formed over the posterior and central jjortions of the shell by the crossing of the oblique lines; the denticulated margin faces forward and is seen only on the thin epidermal layer, while the general system of oblique fines shows on both the outer layer and the next inner layer of the shell. The shell is built up of several thin layers or lamellfe. The largest specimen of the ventral valve has a length of 9 mm.; width, 5 mm.; a dorsal valve 6 mm. long has a width of 4 mm. Nothing is known of the interior of these valves. Observations. — This is a more elongate species than Obolus (Westonia) bottnicus Walcott and 0. (W.) iinlandensis Walcott. The oblique surface lines have the same general direction as those of the latter species, but they are finely denticulated on their front margin, and cross at the center at a greater angle. Formation and locality. — Middle Ordovician: (105x) Gray, siliceous shales, just below a band of quartzitic .sandstones, probably corresponding in position to the upper part of the Simpson formation of the Oklahoma section, Wasatch Canyon, east of Lakeview Ranch, about 5 miles (8 km.) north of Brigham, Boxelder County, Utah. Obolus (Westonia) escasoni (Matthew). Plate XLIX, figures 1, la-f. Lingulella (?) escasoni Matthew, 1901, Bull. Nat. Hist. Soc. New Brunswick, vol. 4, pt. 4, No. 19, pp. 270-273, PI. V, figs. la-i. (Described and discussed as a new species. The specimens represented by figs. Id and Ig are redrawn in this monograph, PI. XLIX, figs, lb and la, laa, respectively.) Oholus {Westonia) escasoni (Matthew), Walcott, 1901, Proc. U. S. Nat. Mus., vol. 23, p. 691. ' (Merely changes generic reference.) Westonia escasoni Matthew, 1903, Geol. Survey Canada, Rept. Cambrian Rocks Cape Breton, pp. 206-209, PI. XVI, figs. la-i. (Copied from Matthew, 1901a, pp. 270-273, PI. V, figs, la-i.) General form ovate, with the ventral valve broadly subacuminate and the dorsal valve rounded oval in outline. The valves are moderately convex, the ventral being most prominent 460 CAMBEIAN BRACHIOPODA. toward the beak. The convexity gives a depth of about 1 mm. to shells 5 mm. in diameter. Surface marked by radiating strise, concentric hnes of growth, and fine, more or less unchilating transverse striae. "When the thin outer layer of the shell is exfoliated, the next layer is marked by rather strong, radiating striae and concentric strisB and lines of growth. The inner surface of the shell is strongly pitted, even over the visceral area, and the anterior and lateral margins are marked by the impressions of the fine canals of the vascular system. The character of the transverse lines is fuUy shown by Plate XLIX, figure If. The shell is relatively thick, and formed of a very thin outer layer and several inner layers or lamellse, which are more or less oblique to the outer layer. These layers are well shown by the posterior portion of Plate XLIX, figure la. The shell is small, the largest not exceeding 6 mm. in length. The dorsal valve is slightly shorter than the ventral. The relative dimensions of the two valves may be seen by comparing figures 1 and lb of Plate XLIX. The details of the area of the ventral valve are not well shown by any specimens in the collection. The pedicle gi'oove appears to have been well marked, and the area to have extended a short distance out on the cardinal slopes. The area of the dorsal valve is larger in proportion than usual when compared with that of the ventral valve. The strife of growth cross it parallel to the anterior margin. The interior of the ventral valve is shown by Plate XLIX, figure la, which beautifully preserves the central portion, and by the cast (fig. 1). The heart-shaped pit (x), so character- istic of Oholus, is clearly defined in figure la, where it strongly resembles the same space in Oholus apollinis Eichwald (PI. VII) . No traces of a median septum have been observed in the ventral valve, but in the dorsal valve the median ridge extends from back of the central muscle scars to the anterior lateral scars. A strong, pestle-shaped depression extends in the ventral valve from the area forward to the anterior margins of the visceral cavity. The visceral area of the dorsal valve is narrow, elongate, and extends forward to the anterior third of the valve. Owing to the small size of the shell and the exfoliation along the margins, no one valve shows all of the muscle scars belonging to it. In Plate XLIX, figure la, the outside lateral, mid- dle lateral, and central scars are beautifully defined, but the transmedian and anterior laterals have not been observed in the ventral valve. Many specimens show the anterior laterals and centrals of the dorsal valve, also the transmedian. The outside and middle laterals appear to be combined in one scar a little anterior to the transmedian. The umbonal and pedicle scars have not been observed. Of the markings left on the shell by the vascular system the main or trunk canals are the most pronunent. They are, however, rather indistinct in most examples of the dorsal valve and not specially prominent in the ventral valve. The channels occupied by the fine branches of the exterior lateral canals are well shown by Plate XLIX, figures la and Ic. Ohservations. — I have made a very close examination of Matthew's type 'material, which he kindly sent to me for examination, but do not find the muscle scars of the ventral valve as shown in his figure Ig [Matthew, 1903, PL XVI]. On the contrary, as shown in my Plate XLIX, figure la, the outside and middle laterals and central muscle scars are arranged very much as in Oholus. It is exceedingly difficult to determine the exact position and size of the muscle scars, but with a strong magnifying glass and reflected light the dull surface of the point of attachment can often be determined. The peculiar arrangement of the muscle scars indicated in Matthew's figure [1903, PI. XVI, fig. Ig] results from examining the specimen in a light which raises the ridges bounding the muscle scars so as to give the effect of transverse lines. I find that the. scars are not placed in exactly the same position on the two sides, and that on the left side it is practically impossible to determine the outside laterals. In the study of such minute objects there will always be an opportunity for different interpretation, but with the experience I have had in the study of the Cambrian Brachiopoda, I think the position given the muscle scars in figure la is essentially correct. The characteristic transverse sculp- ture refers the species to Westonia. It is a beautiful shell and one of the most striking forms of this type from the Cambrian rocks. OBOLID^. 461 The specific name is derived from "Escasonie," a local name for that part of Cape Breton in which the species occurs. Formation AND locality. — ^Upper Cambrian: (325 [Matthew, 1903, p. 208]) Arenaceous shales possibly from the horizon of the Peltura fauna {Division CSb), on McAdam shore; and (10r)« arenaceous shales of Di\ision C3a? of Jlat- thew at McAdam shore; both on East Bay, east of Bras d'Or Lake, southeastern Cape Breton, Nova Scotia. Middle? Cambrian: (lOo)'' Arenaceous shales in the raUroad cut on the shore of Brasd'Or Lake, atBarachois; and (llz) sandstone on Big Ridge, 2 niHes (3.2 Jjm.) south of Marion Bridge, on the canal of John McDougald; both in southeastern Cape Breton, Nova Scotia. Obolus (Westonia) euglyphxjs (Walcott). Plate XLVIII, figures 1, la-f . Ololus (TAngulella) euglyphus Walcott, 1898, Proc. U. S. Nat. Mus., vol. 21, pp. 402-403. (Described and dis- cussed essentially as below as a new species.) Obolus ( Westonia) euglyphus Walcott, 1901, Proc. U. S. Nat. Mus., vol. 23, p. 691. (Merely changes generic reference.) General form ovate, with the ventral valve sub acuminate, and the dorsal valve broad ovate in outline. There is some range of variation in the outline of the valves; this may be seen by comparing figures 1, lb, and Ic of Plate XLVIII. The convexity of the valves is fairly strong and is nearly the same in each. A ventral valve 11 mm. in length has a width of 8 mm., convexity 1.5 nun.; and a dorsal valve 9 mm. in length has a width of 8 mm., con- vexity 1.5 mm. The outer surface of the shell is marked by strong concentric lines and striae of growth and a complex system of lameUose striae of the type of those on Oholus ( Westonia) ella (Hall and Whitfield). The strife have a transverse direction, are irregular, and sometimes inosculate. They are somewhat coarser than those on the surface of 0. ( W.) ella (PI. XLVII, fig. 1 1) and finer than those of 0. ( W.) aurora (HaH) (PI. XLVI, figs. Ih and Ig). They are also less irregular than those of 0. ( TT.) ella, and more so than those of 0. ( W.) aurora, the result being a surface character intermediate between those of the species mentioned. When the outer layer is exfoliated the surface of the inner layer is marked by numerous fine, radiating striae (PI. XLVIII, fig. lb) and concentric lines of growth. The cast of the inner surface of the shell shows rather numerous jiapiUse that fiU the pits or punctae in the shell. The sheU is strong and formed of a tliin outer layer and several inner layers or lamellae that are arranged very much as in LinguJella acutangula (Roemer) (PL XVII). As shown by casts of the interior the cardinal area of the ventral valve is rather long and well extended out on the cardinal slopes. It is divided at the center by a cast of a strong, rather deep pedicle furrow, and about three-fifths of the distance between the pedicle furrow and the lateral margin by a sharp, narrow flexure line. The striae of growth cross the area parallel to its base. Only a few traces of them are preserved in the pedicle furrow. The area formed a thin shelf between the pedicle groove and the lateral margins, the undercut extenduig far back under the area as in L. acutangula. This is shown in the cast by a tliin projection of -the embedding rock over the area (PI. XLVIII, figs. Ic and Id). The area of the dorsal valve is lower and less prominent. It arches forward at the median line and extends well out on the cardinal slopes. The cast of the visceral cavity (v) of the ventral valve includes the heart-shaped pit (x) and a slight trace of the trapezoidal area, in which the central muscle scars and the middle and outside lateral muscle scars occur. There are no traces of a median septum in the ventral valve, and it is only slightly indicated in one specimen of the dorsal valve. This is owiag, however, more to the condition of preservation of the specimen than to the character of the septum. No muscle scars are clearty defined iu either valve. Of the vascular system the main or trunk sinuses are fairly well shown in the ventral valve (PI. XLVIII, figs. Ic and Id), but less so for the dorsal valve (PL XLVIII, fig. le). Observations. — This form has the general shape of Lingulella acutangula (Eoemer), but differs in being more ovate; it also differs in the arrangement of the markings on the interior a The specimens from Localities lOo and lOr are somewhat doubtfully referred to this species. 462 CAjVIBRIAN braohiopoda. of the valves, particularly the dorsal. In Obolus ( Westonia) euglyphus the traces remaining on the casts mdicate a close resemblance to 0. (W.) chuarensis (Walcott), and the surface ornamentation is of the same character. Attention has been called to the character of the surface, which is intermediate between that of 0. ( TT'.) ella (Hall and Wliitfield) (p. 456) and 0. (W.) aurora (Hall) (PI. XLVI). This species differs from Lmgulella Uneolafa (Walcott) in its surface characters, thick- ness of shell, and usually in outline; it is also usually a larger species, although a few examples of L. Uneolafa approach it in size. Fi'om 0. ( TT.) chuarensis it differs in being much more elongate and proportionately more ovate in outline. Formation and locality. — Middle Cambrian: (74c) "Tonto" sandstone, at the head of Lava Canyon; and (74) sandstones about SOO Jcet (91.4 m.) above the base of the Tonto group, at the head of Nunkoweap Valley; both in the Grand Canyon of the Colorado, Arizona. Obolus (Westonla) finlandensis Walcott. Plate XLVIII, figures 3, 3a-b. Obolus (Westonia) finlandensis Walcott, 1902, Proc. U. S. Nat. Mus., vol. 25, pp. 611-612. (Described and discussed as below as a new species.) General form elongate ovate, with the ventral valve subacuminate and the dorsal valve ovate in outline. Convexity of the two valves moderate. A ventral valve 11 mm. in length has a convexity of about 1.25 mm., and a dorsal valve 8 mm. in length has a convexity of 1 mm. above the plane of the margin. The outer surface of the shell is marked by concentric lines of growth with very fine inter- stitial strife. The latter are crossed by fine, radiating strise that are interrupted more or less by the concentric lines of growth. In addition to the concentric and radiating striae there is a series of imbricating hnes that are slightly oblique to the longitudinal axis of the shell. These lines terminate at right angles to the margins, curving inward and backward apparently to the opposite side. This type of ornamentation is much like that of several species of Westonia, except that it is somewhat more complicated. The cast of the interior of the shell shows the interior surface to have been marked by scat- tered punctse that had a tendency to gather concentrically on the lines of growth. A few rather strong radiating stride also occur outside of the visceral area. The shell is rather tlrick. It is formed of a thin outer layer and several inner layers or lamellfe that are more or less oblique to the outer surface and marked near the front margin by fine radiating strise. The largest specimen has a length of 11 mm., with a width of 7 mm. A dorsal valve of the same width has a length of 8 mm. The area of the ventral valve is unlaiown. That of the dorsal valve is strongly defined and extends well forward on the cardinal slopes. It is marked by transverse strife of growth parallel to the base. The only interior markings known are in the dorsal valve. These indicate the course of the main vascular sinus, and the size and length of the median ridge, also the position of the central muscle scars. Observations. — The oblique, imbricating lines on the outer surface of this species relate it closely to Oholus ( Westonia) hottnicus (Wiman) and 0. (W.) wimani Walcott. The two speci- mens showing the outer shell are unfortunately slightly worn along the median line, so that it is not possible to trace the growth of the oblique, imbricating lines entirely across the shell. In form the shell resembles Lingulella acutangula (Roemer). For.mation and locality. — Middle Cambrian: (311x) Compact, fine-grained, quartzitic sandstone at Saltvik, Aland Island, Finland, Russia. Obolus (Westonia) iphis Walcott Plate XLIX, figures 4, 4a-d. Obolus ( Westonia) iphis Walcott, 1905, Proc. I". S. Nat. Mus., vol. 28, p. 336. (Described as below as a new species.) The general form of this shell is well shown by the illustrations. It differs from all other species of Westonia in having a more elongate and acuminate ventral valve and in the presence OBOLIDtE. ' 463 of a marked mesial depression on tlie dorsal valre. Tlie shell is rather tliin and made up of several very thin layers or lameUse. The outer surface is marked by fine radiating strise, con- centric striiB and lines of growth, and fine, more or less undulating, transverse lines that cross both the radiating and concentric lines. The transverse lines appear to be the edges of shghtly elevated imbricating lameUse of the shell. Formation and locality. — Lower Ordovician : (201a) Pogonip limestone, east slope of the ridge east of Ram- burg Ridge, Eureka district [Hague, 1S92, Atlas], Eureka County, Nevada. Upper Cambrian: (64) Limestone near the Bullwhacker mine, Eureka district [Hague, 1892, Atlas], Eureka County, Xevada. (54j) About 700 feet (213.4 m.) above the Middle Cambrian and 525 feet (160 m.) below the top of the Upper Cam- brian, in the arenaceous limestone forming 2c of the St. Charles formation [Walcott, 1908f, p. 192], in Blacksmith Fork Canyon, about 10 miles (16.1 km.) east of Hyrum, Cache County, Utah. Obolus ? (Westonia ?) LAMELLOSUS (Barrande) . Plate XII, figures 7, 7a-d. Lingula lamdlosa Barrande, 1879, Systeme silurien du centre de la Boheme, vol. 5, PI. CVI, figs, i: 1-5; PI. CXI, figs, ix: 1-3. (Xot described, but figured as a new species. PI. CVI, figs, i: 2A, i: 3t, and PI. CXI, figs, ix: 2A; ix: lA, and ix: If are copied in this monograph, PL XII, figs. 7, 7a-d, respectively.) Oholus {Westonia?) lamellosus (Barrande), Walcott, 1901, Proc. U. S. Xat. Mus., vol. 23, p. 691. (Merely changes generic reference.) This species appears to be the Bohemian Lower Ordovician representative of Oholus ( Wes- tonia) stoneanus (Whitfield) of the Upper ^Mississippi Valley Middle Cambrian fauna. The two forms agree in relative size and proportions and in type of surface ornamentation. Tiiis may be seen by comparing figures 2, 2a-g, Plate XX\TII, with figures 7, 7a-d, Plate XII. Another point of similarity is that both species are very abundant in the locahties in which they occur. The principal differences to be noted are that Ol ( WJ) lamellosus has apparently a tliicker and stronger shell than 0. (TF.) stoneanus. This, however, may be due to the fact that all the specimens of the latter species are more or less flattened in the shaly sandstone, and that the shell substance has been largely removed by solution. It is on account of the resemblance of the two forms that Barrande's species is referred to the genus Obolus and subgenus Westonia, despite the absence of any knowledge of the area or the interior vascular markings or muscle scars. It is hoped that the paleontologists of Bohemia ^viU take up the study of this species and others that have been referred to Oholus, in order to establish clearly their generic relations. Formation and locality. — lower Ordovician: (3031 [BaiTande 1879b, PL CVI]) Etage dl, Libetschov, Bohemia, Austria-Hungarj-. Obolus (Westonia) xotchexsis Walcott. Plate LXIII, figure 9. Obolus (Westonia) notchensis Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, p. 69, PL VII, fig. 13. (Discussed as below as a new species. Fig. 13 is copied iu this monograph, Plate LXIII, fig. 9.) This species is represented by two specimens of the ventral valve that have the general outline of Lingulella ampla (Owen) (PL XXVIII, figs, la and If). The exterior surface is marked by concentric lines of growth and transverse, irregular, imbricating lines much like those of Oholus (Westonia) stoneanus (AMiitfield) (PL XXVIII, fig. 2) and 0. (W.) ipliis (PL XLIX, figs. 4a-c). The form of the valve differs from that of the latter species. The largest specimen has a length of 11 mm., with a maximum width of 9 mm. The specific name is derived from Notch Peak, L'tah, on wliich the species occurs. Formation and locality. — Lower Ordovician: (105t) Thin-bedded, bluish-gray limestone [Walcott, 1908f, p. 173 and Pis. XIII and XIV], at the summit of Xotch Peak, House Range, Millard County, Utah. Obolus (Westonia) rogersi (Walcott). Plate XLII, figures 2, 2a-d. lAngula prima Rogers [not Conrad MS., Hall], 1861, Proc. Boston Soc. Nat. Hist., vol. 7, p, 390. (Mentioned.) Lingula antiqua Rogers [not Emmons], 1861, idem, p. 390. (Mentioned.) 464 CAJ\iBRIAN BRACHIOPODA. Obolus (Lingulella) rogersi Walcott, 1898, Proc. U. S. Nat. Mus., vol. 21, pp. 413-415. (Described and discussed essentially as below as a new species.) Lingulella rogersi (Walcott), Gkabau, 1900, Occas. Papers Boston Soc. Nat. Hist., No. 4, vol. 1, pt. 3, pp. 624-625, Pi. XXXI. fig. 4. (Described and discussed.) Obolus (Weslonia) rogersi Walcott, 1901, Proc. U. S. Nat. Mus., vol. 23, p. 691. (Merely changes generic reference.) General form elongate ovate, with the ventral valve subacuminate and the dorsal valve ovate in outline. There is considerable range of variation in the outline of the valves, owino' largely to distortion apparently produced by movement of the matrix. The convexity of the valves is fairly strong and nearly the same in both, except that the dorsal valve curves more abruptly inward toward the beak. The outer siu-face of the shell usually adheres to the matrix, but, in three specimens, portions of it are preserved wliich show that it is of essentially the same character as that of Oholus ( Westonia) stoneanus (PI. XXVIII). The surface is formed by very fine concentric lines and striffi of growth crossed transversely by strong, imdulating, slightly lamellose hues (PL XLII, figs. 2 and 2d). When the outer layer is exfoliated the inner layers are marked by concentric lines of growth and fine radiating stria?. This is also the character of the inner surface, so far as can be determined from the specimens in the collection. The sheU is rather thick and built up of a thin outer layer and several inner layers or lamellae, the latter becoming increasingly nimierous toward the front. The largest dorsal valve in the collection has a length of 13 mm. -with, a width of 11 mm., and a smaller ventral valve with a length of 12 mm. has a width of 9 mm. The dimensions of most of the specimens in the collection average less than those here given. The area of the ventral valve is relatively short for a species of this tjrpe. It is divided midway, as seen in the cast, by a strong pedicle frurow. Owing to the imperfection of the mate- rial, none of the specimens show flexure lines or stria of growth. The area of the dorsal valve is short and extends but a short distance on either side of the median hne. The cast of the interior of the ventral valve is very much hke that of the iriterior of Oholus cyane (PL XVII). It has the same median ridge and the transverse trapezoidal area wliich includes the central, middle lateral, and outside lateral muscle scars. The main vascidar sinuses are indicated by slight ridges (PL XLII, figs. 2a and 2b). The cast of the interior of the dorsal valve shows a narrow median septum, two central muscle scars of average size, situated a short distance back of the center of the shell, and two small anterior lateral scars, located some distance in advance of the center, which give an elongated visceral cavity somewhat like that of Lingulella hayesi (PI. XXV) of the Middle Cambrian and Oholus lamhorni (PL XXII) of the Upper Cambrian. Ohservations. — The external form of the more elongate specimens of tliis species is very much like that of Lingulella acutangula (Roemer) (PL XVII). When compressed laterally it occasionally has the form of Lingulella (Lingule-pis) acuminata (Conrad). It is distmguished, however, fi'om all described species of Westonia known to me by its higlily characteristic surface ornamentation. Oholus {Westonia) stoneanus (PL XXVIII) has the same type of surface, but it differs from the latter in being a much more elongate shell. The material described in tliis monograph was collected by Prof. N. S. Shaler and Mr. J. B. Woodworth from the pebbles on the beach on the northern shore of Marthas Vineyard, Massa- chusetts, and at several points along the shores of Narragansett Ba_y. The first notice we have of these fossiliferous pebbles is that by W. B. Rogers, who [1S61, p. 389] annoimced the discovery, by Norman Easton, of pebbles carrying fossils of the Potsdam fauna in the Carboniferous conglomerate north of Fall River, Massachusetts. In 1875 [p. 100] Rogers announced the discovery of impressions, suggestive of the fossil Lingulas mentioned by him from Fall River, in the pebbles in the conglomerate at Newport, Rhode Island. He thought that the pebbles were derived from rocks probably closely connected in time with the Braintree Paradoxides zone. Among the material sent by Professor Shaler I ioxmd the remains of a large Linguloid brachiopod, which appears to be identical with Oholus (Linguloholus) affinis (Billings), fi-om the Lower Ordovician rocks of Newfoundland. The material is somewhat imperfect, but I OBOLID^. 465 do not know of any other large brachiopod of this type fi-om the Cambrian or Ordovician rocks. The reference to the Lower Ordovician is made by reason of the presence of this Lingulobolus. The specific name is given for Mr. W. B. Rogers, who first called attention to the species. Formation and locality. — Lower Ordovician : (326) Limestorie pebbles on the beach on the northern shore of liarthas Vineyard; and (326a [Grabau, 1900, p. 613]) limestone pebbles in a Carboniferous conglomerate north of Fall River, Bristol CJounty; both in Massachusetts. (343 [Rogers, 1875, p. 11, and U. S. Nat. Mils.']) Limestone pebbles on the beach near Newport and at several points along the shores of Narragansett Bay, Rhode Island. (114b) Sandstone 1 mile (1.6 km.) north of Lance Cove, Great Belle Island, Conception Bay, Newfoundland. Obolus (Westonia) stoneanus (Whitfield). Plate XXVIII, figures 2, 2a-g; Plate XLIX, figures 2, 2a. Lingula aurora var. Hall, 1863, Sixteenth Ann. Rept. New York State Cab. Nat. Hist., pp. 127-128, PI. VI, figs. 6-8. . (Described and discussed.) Lingula aurora var. Hall, 1867, Trans. Albany Inst., vol. 5, pp. 104-106, PL I, figs. 6-S. (Copy of preceding reference.) Lingulella aurora var. Hall, 1873, Twenty-third Ann. Kept. New York State Cab. Nat. Hist., pp. 244-245, PL XIII, fig. 5. (Mentions change of genus. Fig. 5 is drawn from the same specimen as Hall, 1863, PL VI, fig. 7.) Lingulella stoneana Whitfield, 1882, Geology of Wisconsin, vol. 4, pp. 344-345, PI. XXVII, figs. 6 and 7. (Charac- terized and discussed as a new species.) Lingulella stoneana 'WTiitfield, Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, PI. II, figs. 9-11. (No text reference. Figs. 9 and 11 are copied from Hall, 1863, PL VI, figs. 7 and 8, respectively; and fig. 10 from Hall, 1873, PL XIII, fig. 5.) Lingulella stoneana T\Tiitfield, Weller, 1903, Geol. Survey New Jei-sey, Kept. Paleontology, vol. 3, p. 112,-Pl, I, fig. 6. (Described and discussed. The specimen represented by fig. 6 is redrawn in this monograph, PL XLIX, figs. 2 and 2a.) Obolus (Westonia) stoneanus (T\1iitfield), Walcott, 1901, Proc. U. S. Nat. Mus., vol. 23, p. 691. (Merely changes generic reference.) In form Obolus (We.stonia) stoneanus (PI. XXVIII) approaches quite closely to the more rounded shells of Lingulella ampla (Owen), except that in the dorsal valve the posterior lateral slopes are broadly rounded, giving a subelliptical outline to the valve. The original convexity of the valves is not preserved, but it appears to have been moderate, like that of Lingulella ampla. A large ventral valve from Prairie du Sac has a length of 15 mm., with a maximum width of 11 mm. An associated dorsal valve, 10 mm. wide, has a length of 11.5 mm. The surface of the shell is strongly characteristic. It is formed by very fine concentric lines or strite of growth crossed transversely b}^ strong, undulating slightly lamellose lines (PI. XXVIII, fig. 2d, and PI. XLIX, fig. 2a). The margins of the inner surface of the shell show fine radiatmg lines. All of the large number of specunens in the collection are flattened in the shaly sandstone, and there is usually little left of the substance of the shell to afford a basis for an opinion of the fonn or thiclvuess. A careful study of the material, however, leads to the conclusion that the valves were moderately convex and comparatively thin. In casts of the interior the concentric strise and transverse lamellose lines are almost invariably strongly marked, and no traces of the interior muscle scars or marldngs are preserved. The area of the ventral valve, as seen in a cast, is divided midway by the cast of the strongly marked pedicle groove and, on each side and well out toward the margin, by the flexure lines. The few stride of growth preserved cross the area parallel to its base. On the dorsal valve the area is short, broad, and slightly arched forward near the center; the flexure lines are fairly well preserved in a compressed cast of the shell. No muscle scars or vascular markings have been observed on the interior casts of the ventral valve. A dorsal valve shows the central muscle scars (h) and the base of the main vascular sinuses (vs) (PI. XXVIII, fig. Ih). Observations. — This species was separated as a variety of Obolus (Westonia) aurora by •Professor Hall [186.3, p. 127]. Later [1882, p. 344], Professor Wliitfield, finding that its pecu- Haiities persisted in specimens found at localities where 0. (W.) aurora did not occur, gave it a specific name. The peculiar surface ornamentation clearh^ distiaguishes it from other species 62667°— VOL 51, pt 1—12 30 466 CAJMBRIAN BEACHIOPODA. of the genus except 0. (IF.) aurora, from which it difTers in having a more elongate form and in the fact that the surface markmgs, though of the same type, vary in being much coarser and in having longer undulations. (Compare PL XXVIII, fig. 2d, with PI. XL VI, fig. Ih.) The form found by Stuart Weller [1900, p. 112] in the Upper Cambrian sandstones of nortli- ern New Jersey is illustrated on Plate XLIX, figures 2, 2a. The specific name was given for Mr. R. E. Stone [Wliitfield, 18S2, p. 345]. FoKMATioN AND locALiTY. — Upper Cambrian: (85x) Upper beds of the "St. Croix sandstone" at Mazomanie, Dane County; (81b) "St. Croix sandstone" near Devils Lake, Sauk County; (328m) sandstone 1 mile (1.6 km.) south of Osceola, Polk County; (328f [Hall, 1863, p. 128]) sandstone at the falls of St. Croix River, Polk County; and (85 and 8Ss)o "St. Croix sandstone" at Prairie du Sac, Sauh County; all in Wisconsin. (lie) Hardyston quartzite [Weller, 1903, pp. 110 and 112], O'Donnell and McManniman's quarry, Newton, Sussex County, New Jersey. (327) Ai-enaceous limestone east of Gold Camp; (327a) arenaceous limestone about 500 feet (152 m.) above the base of the Cambrian in McKinley Canyon; (327b) arenaceous limestone near the base of the section on the south side of Cerro Cuchillo ; and (327c) arenaceous limestone in the Caballos Mountains (exact locality unknown) ; all in the Caballos Mountains, Sierra County, New Mexico. Obolus (Westonia) THEMIS Walcott. Plate XI, figures 2, 2a-c. Obolus (Westonia) themis Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 336-337. (Described and discussed as below as a new species.) General form subsemicircular, with the ventral valve subacuminate and the dorsal valve broadly ovate in outline. Valves rather strongly convex. Surface of the shell marked by strong concentric lines of growth with finer intermediate strias ; in addition there are very fine, irregular, raised, more or less transverse stria? that inosculate, forming a minutely papillose or granular surface much like that of Oholus (Westonia) elta (PI. XLVII). It often occurs that the outer surface has been removed by attrition in the sand, so that the shell has a smooth polished surface. Owing to the condition of preservation the markings of the inner layers are not preserved. The shell is strong and thick in advance of the center. It is made up of the thin outer surface layer and several inner layers or lamelhie that in the posterior portions are slightly oblique to the outer surface. After the shell has attained a size of 2 or 3 mm. the lamellse are more oblique to the outer surface and form a thick, strong shell, the outer edges of which often produce a rather rough surface. This is shown by the figures iUustrating the species. The largest ventral valve in the collection has a length and breadth of 10 mm.; a dorsal valve 10 mm. in length has a width of 11 mm. The only interior portions of the shell known are on a fragmentary ventral valve in which the visceral area does not reach the center, and the main vascular sinuses are about halfway between the center and the lateral margins of the valve. Observations. — The general form of the shell is much Uke that of Oholus loperi (PI. IX) . It difi'ers from the latter in surface characters. Formation and locality.— Middle Cambrian: (17c) Sandy limestone 235 feet (71.6 m.) above the "Tonto' ' sand- stone. Grand View trail, north of Last Chance copper mine, south side of the Grand Canyon of the Colorado, Arizona. Obolus (Westonia) wasatchensis Walcott. Text figures 41A-P, page 467; Plate XLIX, figures 5, 5a. Obolus ( Westonia) wasatchensis Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, pp. 69-70, PI. VIII, figs. 1 and la. (Discussed as below as a new species. Figs. 1 and la are copied in this monograph as figs. 41A and 41D.) This species is founded on some large shells that differ from Oholus ( Westonia) ella (Hall and Whitfield) (PI. XLVII) in attaining a larger size and greater proportional width and in a 85s is the type locality, tlioagli the specimens in the United States National Museum to which that number is assigned were collected much later than the type specimens. OBOLID^. 467 having the surface marked by radiating lines that extend from the umbo with a gentle curva- ture toward the sides and front of the shell, so as to terminate at right angles to the margin, very much as in Oholus (Westonia) finlandensis (PL XLVTII, figs. 3 and 3a). In the Blacksmith Fork section of the Middle Cambrian terrane in the Wasatch Moun- tains of northern Utah 0. (IF.) wasatchensis occurs 1,590 feet higher in the section than 0. (W.) ella. The specific name is derived from its occurrence in Wasatch Canyon, Utah. Formation and locality. — Middle Cambrian : (34u) Shales about 950 feet (289.6 m.) above the Cambrian quartzitic beds, 2 miles (3.2 km.) southeast of Muski-at Spring, on the northwest face of Grantsville Peak, Stansbury Range, Tooele County; and (33t) shale about 1,500 feet (457.2 m.) above the Brigham quartzite, 1 mile (1.6 km.) northwest of Geneva (Copenhagen), east of Brig- ham, Boxelder County; both in Utah. (64ii) Drift block supposed to have come from the horizon of Locality 32x; (32x) about 1,700 feet (518.2 m.) above the Brigham quartzite [Walcott, 1908a, p. 8], in shales correlated with the shales forming 2d of the Bloomington formation in Blacksmith Fork Canyon [Walcott, 190Sf, p. 195]; and (33j) about 2,300 feet (701 m.) above the Brigham quartzite; all in Wasatch Canyon, east of Lakeview Ranch, 5 miles (8 km.) north of Brigham, Box- elder County, Utah. (541i) About 3,140 feet (957.1 m.) above the Brigham quartzite [Walcott, 1908a, p. 8] and 1,050 feet (320 m.) below the Upper Cambrian in the lime- stones forming la of the Bloomington formation [Walcott, 1908f, p. 194]; and (54k) about 2,100 feet (640 m.) above the Lower Cambrian and 2,100 feet (640 m.) below the Upper Cambrian in the shales forming 2d of the Bloom- ington formation [Walcott, 190Sf, p. 195] ; both in Blacksmith Fork Canyon, about 10 miles (16.1 km.) east of Hy- rum. Cache County, Utah. (55d) About 2,000 feet (609.6 m.) above the Cambrian quartzitic beds, in a shale which is probably to be referred to the Bloomington formation [Walcott, 1908a, p. 7], on the south side of Twomile Canyon near its mouth, 2 miles (3.2 km.) southeast of Malade, Oneida County, Idaho. E D Figure i\.— Oholus (Westonia) wasatchensis Walcott. A, Elongate ventral valve, the type specimen (U. S. Nat. Mus. Cat. No. 51733a). B, Interior view of an elongate ventral valve (U.S. Nat. Mus. Cat. No. ol737a). C, Interior of a broken, flattened ventral valve (U. S. Nat. Mus. Cat. No. 51734b). D, E.xterior of dorsal valve (U. S. Nat. Mus. Cat. No. 61734a). E, Interior of a flattened dorsal valve (U. S. Nat. Mus. Cat. No. 61734c). F, Interior of a dorsal valve (U. S. Nat. Mus. Cat. No. ol734d). The specimens represented by figures 41.\ and 4115 are from Localities 54q and 55d, respec- tively: and those represented by figures 41C-F are from Locality 54k. Figures 41A and 41D are copied from Walcott [1908d, PI. VIII, figs. 1 and la, respectively). Obolus (Westonia) wimani Walcott. Plate XLVIII, figures 5, 5a-b. Lingula ? sp. No. 1, Wiman, 1902, Bull. Geol. Inst. Univ. Upsala, vol. 6, pt. 1, No. 11, p. 51, PL II, fig. 36. (Locality mentioned.) Lingulella? sp. No. 1, Wiman, 1902, idem, p. 52, PL II, fig. 30. (Locality mentioned. The specimen represented by fig. 30 is redrawn in this monograph, PL XLVIII, fig. 5.) Lingulella? sp. No. 2, Wiman, 1902, idem, p. 52, PL II, fig. 31. (Locality mentioned. The specimen represented by fig. 31 is redrawn in this monograph, PL XLVIII, fig. 5a.) Lingulella? sp. No. 7, Wiman, 1902, idem, p. 52, PL II, fig, 32. (Locality mentioned. The specimen represjnted by fig. 32 is redrawn in this monograph, PL XLVIII, fig. 5b.) Obolus (Westonia) wimani Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 337. (Discussed essentially as below as a new species.) The general form of this species is not unhke that of Oholus ( Westonia) iottnicus (Wiman) (PI. XLVIII). The cardinal slopes of the ventral valve are more rounded, which makes the valve broader near the center. All of the specimens are also smaller. The surface markings 468 CAilBKIAN BRACHIOPODA. are of the same character as those of Oholus ( Westonia) jinlandensis Walcott (PI. XLVIII) and 0. ( F.) bottnicus. It is not improbable tliat with the discovery of a large series of specimens the three species may be combined, or 0. ( TF.) hottnicus and 0. ( W.) wimani placed as varieties of 0. ( W.) jinlandensis. For reference to the geological horizon of bowlders on Eggegrund Island, similar to the ones containing this species, see description of 0. ( TF.) hottnicus, page 454. The specific name is given for Dr. Carl Wiman, of the University of Upsala. Formation and locality. — Middle? Cambrian : (311c, 311g, and 3111)o Drift bowlders of bituminous sandstone, Nos. 7, 16, and 27 [Wiman, 1902, p. 57], onBiludden, abolitSO miles {32.2 km.) east of Gefle, Province of Gefleborg, Siveden. (311t) Drift bowlder of mottled calcareous sandstone [Wiman, 1902, p. 57], at Ofverby, parish of Jomala, Aland Island, Finland, Russia. Obolus (Westonia) sp. undt. a. Fragments of a species of Obolus with a very minutely reticulated surface occur in associa- tion with Cyrtoceras cwmbria Walcott and suggest Obolus ( Westonia) ella, except that the surface ornamentation is so minute that it can only be seen with a strong lens. The fragments indicate a shell about the size of 0. ( IF.) ella. Formation and locality. — Upper Cambrian : (C56) Lower part of Cliaumitien limestone, 25 feet below the top of Pagoda Hill [Blackwelder, 1907a, p. 42 (part of last list of fossils)], 1 mile (1.6 km.) west of Tsinan, Shantung, China. Obolus (Westonia) sp. undt. b. Fragments of a shell showing the characteristic surface ornamentation of Westonia occur in the Ordovician limestone, Eureka district, Nevada. The shell must have been at least as large as Obolus ( Westonia) stoneanus (Whitfield) , but the material is too imperfect for identification. Formation and locality. — Passage beds between the Upper Cambrian and the Ordovician: (205) siliceous limestone on Roundtop Mountain, Eureka district [Hague, 1892, Atlas], Eureka County, Nevada. Genus LINGULELLA Salter. [I-ingula.] Tellinomya McCoy [not Hall], 1854, British Paleozoic Fossils, p. 274. (Described from distorted specimens of Lin- gulella davisi (McCoj^).) Lingulella Salter, 1866, Mem. Geol. Survey Great Britain, vol. 3, p. 333. (Described and discussed as a new genus.) "The name Lingulella was first introduced about 1861, with the late Dr. S. P. Woodward's full consent; and the name appears at page 9 of Sir Roderick Murchison's address to the geological section of the British Asso- ciation, Manchester, 1861," but was not described (see Davidson, 1866, p. 55). Lingulella Salter, Davidson, 1866, British Fossil Brachiopoda, vol. 3, pt. 7, No. 1, p. 55. (Original description copied and Lingulella discussed as either a genus or subgenus.) Lingulella Salter, Davidson, 1868, Geol. Mag., vol. 5, p. 304. (Genus discussed.) Lingulella Salter, Dall, 1870, Am. Jour. Conchology, 2d ser., vol. 6, pt. 2, pp. 153 and 159. (Described.) Lingulella Salter, Meek, 1871, Proc. Acad. Nat. Sci. Philadelphia for 1871, vol. 23, pp. 186-187. (Notes on genus in discussion of "Lingulella lamborni.") Lingulella Salter, Dall, 1877, Bull. U. S. Nat. Mus. No. 8, p. 44. (Mentioned.) Lingulella Salter, Zittbl, 1880, Handbuch der Palseontologie, Bd. 1, Abth. 1, pp. 663-664. (Described in German.) Lingulella Salter, Salter and Etheridge, 1881, Mem. Geol. Survey Great Britain, vol. 3, 2d ed., p. 537. (Copy of Salter, 1866b, p. 333.) Lingula {Lingulella) Salter, Oehlert, 1887, Manuel de conchyliologie, by Fischer, p. 1261. (Described in French.) Lingulella Salter, Bornemann, 1891, Nova Acta Acad. Cses. Leop. Carol. Germanicse Naturae Curiosorum, Bd. 56, No. 3, pp. 435^37. (Discussed in German.) Lingulella Salter, Hall and Clarke (in part), 1892, Eleventh Ann. Rept. State Geologist New York for 1891, pp. 232-233. (Described. Lingulella davisi is given as the type, but as a generic illustration Botsfordia cselata is figured on PI. III.) Lingulella Salter, Hall and Clarke (in part), 1892, Forty-fifth Ann. Rept. New York State Museum for 1891, pp. 548-549. (Copy of preceding refei-ence.) a 311c is the type locality. OBOLID^. 469 Lingulella Hall and Clarke (in part), 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, pp. 55-59. (Original description copied and genus discussed. Lingulella davisi is given as the type, but figures of Obolus (Westonia) ella accompany the text and as a generic illustration Botsfordia cxlaia is figured on PI. II. Species belonging with other genera are also mentioned as belonging to Lingulella.) Obolus {Euobolus) Mickwitz (in part), 1896, Mem. Acad. imp. sci. St'.-P6tersbourg, 8th ser., vol. 4, No. 2, p. 129. (Described in German.) Obolus (Lingulella) (Salter). Walcott, 1898, Proc. U. S. Nat. Mus., vol. 21, pp. 390-392. (Discussed.) Lingulella Salter, Matthew, 1899, Bull. Nat. Hist. Soc. New Brunswick, vol. 4, pt. 3, No. 18, p. 201. (Characterized in discussion of Palxoholus, see p. 471, for copy.) Obolus {Lingulella) (Salter), Walcott, 1901, Proc. U. S. Nat. Mus., vol. 23, p. 683. (Characterized.) £oo6o?Ms Matthew, 1902, Trans. Roy. Soc. Canada for 1902, 2d ser., vol. 8, sec. 4, No. 3, p. 97. (Characterized without reference to Mickwitz and without any indication of the fact of its being intended as a new subgenus; see Matthew, 1903, p. 135.) Lingulella Salter, Matthew, 1902, idem, p. 103. (Nova Scotia representatives mentioned.) Leptobolus Matthew [not Hall], 1903, Geol. Survey Canada, Rept. Cambrian Rocks Cape Breton, pp. 105-106_ (Described, see p. 472 for copy.) Lingulella Salter, Matthew, 1903, idem, p. 116. (Discussed.) Obolus (Eoobolus) Matthew, 1903, idem, p. 135. (Characterized as a new subgenus.) Lingulella Salter, Delgado, 1904, Communicagoes Commissao Servipo Geol. Portugal, tome 5. fasc. 2, p. 367. (Dis- cussed in French.) Not iiTi^uZcZta Grabau and Shtmer, 1907, North American Index Fossils, vol. 1, p. 192. (Described, but one of the species referred to belongs with Obolus (Westonia) and the other is the type of that subgenus.) Lingulella Salter, Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 4, PI. XI, and pp. 142 and 144. (Classification of genus.) Type of genus. — Lingula davisi McCoy. Valves subequal, equilateral; elongate ovate, broad ovate, or subtriangular in outliae. Ventral valve usually sub acuminate, -with a distinct area, pedicle groove, and flexure lines. Dorsal valve somewhat shorter, less acuminate, and with a less clearly marked pedicle groove on the shorter area. Beaks terminate at the margin of the areas, which are usually ia the plane of the margins of the valves; the areas, which vary in size and shape ia the different species, are usually more or less triangular; in the ventral valve they may be so shortened and arched as to nearly lose this marked form; the areas of the dorsal valve also vary ia their form length, and extension on the cardinal slopes. Shell substance calcareocorneous; structure consists of a thin outer surface layer and numerous inner layers or lamella that are subparallel to the surface over the posterior portions of the shell and more or less obhque to it over the central, lateral, and anterior portions; the short obhque layers usually form the inner flattened rim of the valves which is frequentlv seen in the casts (PL X^^I, fig. li). Surface of shell marked by fine concentric strife and fines of growth, and in some species finely' inosculatiag, lameUose stride; also, in most if not aU species, radiating strife and lines. The visceral area (splanchnocoele [Mickwitz, 1896]) is usuaUy confined to the central and posterior portions of the ventral valve, but it m&j extend far into the bracliial area (bracliio- coele O'lickwitz, 1896]) (PL XVII, fig. Ic) ; in the dorsal valve it extends farther forward than in the ventral valve of the same species; in both valves it may range from the posterior third of the sheU forward to the anterior third, and in the dorsal well into the latter; in both valves the AQSceral area extends back to the base of the areas where it is bounded exteriorly by the flexure lines (lines of folding of the area lameUa^. A narrow mecfian ridge or septum is frequently observable in the dorsal valve, but -wdth the exception of what may be considered as mdicating its probable presence m one specimen of a -ventral valve of Lingulella- davisi (McCoy) (PL XXXI, fig. 6f), no traces of a septum have been observed in the ventral valve of any of the species that I have studied. The main vascular sinuses vary in size, direction, and length in the various species; in all they begm m front of the area at the median line and extend forward and outward across the parietal band into the central-lateral and anterior parts of the brachioccEle. The impressions of the secondary vascular canals are rarely preserved, but the few traces observed indicate that they were numerous and extended toward the peripheral canal and into the middle of the shell in the direction neces- sitated by the arrangement of the main sinuses and the boundaries of the visceral area. 470 CAJMBRIAN BEACHIOPODA. In the anterior portion of the visceral area of the dorsal valve of some species the "heart- shaped pit" of Obolus is distinctly marked (PI. XVII, fig. If). It is rarely so well shown, although its anterior outline is preserved in nearly all species whose interior characters are well marked. A median ridge may or may not be present in the interior of the dorsal valve. The preservation of all vascular markings depends largely on the thickness of the shell, being rarely seen in thin shells and often found in thick ones. There are six pairs of muscle scars that have been observed, in addition to the pedicle scar (m) which is situated on the ventral valve between the two scars (gg) left by the divided umbonal muscle close to the area; on the dorsal valve the single umbonal scar (g) is just in advance of the base of the area. The central scars (h)' are usually situated about the center of the dorsal valve a short distance each side of a median septum; in the ventral valve they are inclosed in a trapezoidal area (c), with the scars of the outside and middle lateral muscles, on each anterolateral side of the heart-shaped area (x). The transmedian scars are shown as one scar on each side a little in advance of and on a line with the flexure lines of the area; the variation in their relatiA^e position in the two valves and in various species may best be under- stood by studying the illustrations and descriptions of species. The scars (k) of the middle lateral muscles are inclosed within the area (x) with the central and outside laterals; in the dorsal valve they blend with those of the outside laterals (1) in advance and a little outside of the transmedian scars (i). As previously stated, the scars of the outside lateral muscles in the ventral valve are combined with the central and middle laterals, while in the dorsal valve they are united with the middle lateral muscles. The scars of the anterior lateral muscles (j) of the ventral valve are usually so closely united with those of the transmedians (i) that it is only in unusually well-preserved specimens that the two scars can be differentiated; in the dorsal valve they are more or less in advance of the centrals, and divided by a narrow median septum or ridge; they may be situated a little back of the center of the valve or at any distance between that and a short distance from the frontal margin of the shell. In both valves the scar of the parietal band closely circumscribes all muscle scars externally, crossing the main vascular sinuses and terminating at the base of the flexure line of the area. The principal forms of Lingulella may be grouped under five divisions by the outlines of the ventral valve. Acuminate: Ovate-elongate: Lingulella perattenuata (PI. XXI). Lingulella bella (PL XIX). L. acutangula (PI. XVII). Ovate-quadrangular: L. manticula (PL XX). Lingulella mosia (PL XVIII). L. nanno (PL XXIV). L. winona (PL XVIII). Subacuminate: Sub triangular: Lingulella davisi (PI. 'X'SXl). Lingulella aug a {V\. XXIV). Intermediate forms are illustrated by Lingulella martinensis (PI. XXXVIII), which is rounded subtriangular and acuminate, and L. phaon (PL XXVI), which is both acuminate and subacuminate. The outline, relative size, and position of the visceral areas (splanchnocoeles) are exceed- ingly variable. In Lingulella oweni (PL XVIII) the area is very short, while in L. acutangula (PL XVII), L. perattenuata and L. similis (PL XXI), L. punctata (PL XX), and L. radula (PL XLV) it is elongate. The narrow type of visceral area in the dorsal valve is seen in Lingulella acutangula (PL XVII), L. hayesi (PL XXV), L. similis (PL XXI), L. manticula (PL XX), i. leos (PL XXIV), L. ampla (PL XXVIII), and L. radula (PL XLV). The surface characters vary from the almost smooth and highly polished Lingulella nanno (PL XXIV), on which only the faintest traces of radiating strise and depressed rounded lines of growth are visible, to shells with strong concentric striae and lines of growth, Lingulella auga (PL XXIV). Whenever the surface of the shell is sufficiently well preserved to permit close examination radiating strise have been observed. Observations. — Prior to the investigation of the material described and illustrated in this monograph," the data relating to Lingulella were too meager to permit detailed comparison with n Announced in a rreliminary paper: Proo. U. S. Nat. Mus., vol. 21, 1898, p. 390. OBOLID^. 471 other genera. The presence of a pecuHar central channel in the cardinal area was the only character of importance observed by Davidson [1866, p. 55] that served to distinguish Lin- gulella from Lingula. In the original description, Salter [lS66b, p. 333] calls attention to the resemblance of the muscular scars of Lingulella to those of Oholus, but he considers that the difference in relative position is sufficient to distinguish the two genera. Attention is also called [Salter, 1866b, p. 333] to Obolella Billings, and to the fact that the later figures of Billings "show a very different set of muscular scars." Davidson had the same material that Salter had and more, but was unable to find any satisfactory interiors, and hence left the genus as doubtful, evidently considering it as closely related to Lingula. IVIickwitz met with the same difficulty as Davidson, in having unsatisfactory material upon which to base an opinion. After stating [1896, p. 126] that OholeUa Billings would probably have to make room for the genus Oiolus Eichwald, he says: "Whether Lingulella Salter will share the same fate I will not venture to predict with the same degree of certainty, since the diagnosis and figures are even more imperfect than in Billings's genus." When in Wales, in 1888, I made a small collection of Lingulella davisi (McCoy) at thetype locality at Portmadoc, and later Mr. G. J. Williams sent me a number of fine specimens for study. With this material, supplemented by a beautiful series of specimens of a number of American species, it has been possible to obtain a clear conception of Lingulella and its relations to Oiolus, OholeUa, Schnfiidtia, Lingulobolus , Lingulepis, and Lingula. The memoir of Mickwitz [1896] gave the genus Obolus a position tliat it had not held prior to his very thorough investigation. With his descriptions and plates and a fine suite of specimens worked out from material very generously given me by Dr. Fr. Schmidt, I have been able to make a series of comparisons with Lingulella that at times has led me almost to doubt the advisabihty of characterizing Lingulella as generically distinct from Oholus. This distinction is now based on the more elongate form of most of the species of Lingulella, and the greater tliick- ness of the shell of the typical forms of Oholus. There are differences in the position, size, and form of the muscular scars, visceral area, and vascular canals of Oholus and Lingulella, but they are not greater than those between different species referred to Lingulella. The same general arrangement of muscle scars prevails, but on comparing the interior of the dorsal valve of Lingulella davisi (McCoy) (PI. XXXI, fig. 6e) with that of Lingulella acutangula (Roemer) (PI. XVII, fig. Ih) or Lingulella ampla (Owen) (PL XXVIII, fig. Ih) we find as great variation as when the comparison is made with the dorsal valve of Obolus (PL VII, figs. 6-9). The same is true of the ventral valve, although the means of comparison are in this case not so good. One of the oldest species of Lingulella, L. granvillensis Walcott (PL XXII) of the upper Olenellus zone, has the outline of Oholus (Schnfiidtia) celatus Volborth, and the interior markings of the ventral valve are also of the same type. Lingulella acutangula (Roemer) (PL XVII, fig. If) has the heart-shaped pit so characteristic of Oholus (PL VII, figs. 1-4) and the arrange- ment of the muscular scars is essentially as in Oholus, but the outline of the valve is much more elongate. Lingulella davisi (McCoy) and Lingulella ampla (Owen) vary decidedly from Oholus in the interior marldngs, but not more than Lingulella am.pla differs from Lingulella acutangula. The variations are so well shown by the figures on the plates that detailed comparisons will not be entered upon. Matthew [1899b, p. 201] proposed to distinguish Oholus from Lingulella by its — roundness of outline, short cardinal area and depressed beaks, advanced position of muscle scars in the valve, and strong arch of the vascular trunks in the ventral as well as the dorsal valve. There is, however, a more important distinction, which, in consequence of imperfect preservation of the valves, can seldom be observed; that is, the position of the secondary muscles of the central group in the ventral valve, as compared with the great muscle of that group. In Obolus they are lateral, but in Lingulella anterior to the great muscle. This shows a radical difference of structure between the two genera. I am not able to recognize as constant the characters mentioned by Matthew, owing to the great variation in the large group of species referred to Oholus and Lingulella. The data for a clear distinction of the two, Oholus and Lingulella, are still too limited for more than an arbitrary reference of Lingulella to a generic place in relation to Oholus. This is particularly 472 CAIvIBRIAN BRACHIOPODA. the case with the position of the muscle scars of the ventral valve to which Matthew refers. The central muscles of the ventral valve of Obolus vary greatly in the position of the points of attachment; this is shown by Plate Vll/figures 1-13, for Oholus apoUinis. The scarsof thecentral muscles of Lingulella are rarely preserved so that they can all be identified; in one species, LincjuleUa acutangida (PI. XVII, figs. Ic and Ig), they appear to be arranged as in Oholus apoUinis. The same is true for Obolus ( Westonia) escasoni (Matthew) (PI. XLIX, fig. laa). The genus ScJimidtia Volborth is made a subgenus of Oholus by Mickwitz [1896, p. 25]. A comparison of t^ypical specimens of Obolus (Schmidtia) celatus Volborth and Lingulella davisi (IMcCoy) leads to the view that Schmidtia is identical with Lingulella except that Lin^ gulella is a radiallj^ striated shell and Schmidtia is not. I did not fuUy appreciate tliis distinc- tion when writing a preliminary notice [1898, p. 392] of the study of Lingulella and hence referred to Schmidtia as a synonym of Lingulella. An}^ extended comparison with Obolella is unnecessary, as it is a tliick, round-ovate shell with a cardinal area and pedicle opening unlike Lingulella or any of the subgenera of Oholus. Linguloholus has the same arrangement of muscle scars as Lingulella, but differs in the greater tliickness of the shell in both valves. Lingulepis is scarcely more than a very acuminate form of Lingulella with the area and visceral cavity of the ventral valve modified in shape to meet the extreme elongation of the posterior portion of the valve. That Lingulella is closely related to Lingula is seen at once by comparing the markings on the interior of the two shells. Under observations on Oholus (p. 375) the dififerences between Oholus and Lingula have been stated. Lingulella differs from Lingula iu the same manner as Oholus in having its visceral area continued back to the posterior margin of the interior of the valves, but it has the same general form as Lingula. Without the interior of the valves for comparison it would be very difficult to determine that many of the Cambrian species were not true species of Lingula. Matthew [1903, p. 105] refers a group of small shells heretofore placed under Lingulella to the Ordovician genus Leptoholus of HaU. He says: Such forms have usually been included in Lingulella, but in addition to theu- minute size they are separated from that genus by important characters. These little shells have thin test, weak umbones; vascular trunks are situated near the lateral margins, and both the central and lateral muscles in both valves are advanced far toward the front of the valves. As a result of the examination of the types of the Ordovician species of Leptoholus I find that they have quite strong, thick shells in proportion to their size, c^uite as much so as the young shells of species of Lingulella that acquire thickened shells as they attain their fuU growth. The vascular trunks are weU out toward the margin, but this feature also occurs in large forms of Lingulella, as indicated in the table under Obolus (p. 377). The position of the central and lateral muscle scars is also too variable a character to afford a basis for generic reference. Leptoholus is marked by a peculiar visceral area in -the ventral valve unknown in any Cambrian shell, and the bifurcation of the strongly marked ridges of the path of advance of the central and lateral muscle scars in the dorsal valve is a distinguishing character not found in the Cambrian shells referred to Leptoholus. The Cambrian forms referred to Lepto- holus by Matthew [1903] are: L. atavus, L. atavus insulse, L. atavus tritavus, L. collicia, L. collicia collis, L. jlumenis, L. gemmulus, L. cf. linguloides, and L. torrentis. If the above species are included in a distinct genus, several others should go with them, notably: Lingulella ferruginea Salter (PL XXIX), L. lepis (Salter) (PL XXXI), and L. cania CVValcott) (PL XXXV). One of the oldest species known of the genus Lingulella, Lingulella schucherti (Walcott) (PL XXI, fig. 6), is in all respects, so far as can be determined from the material, a true Lingu- lella. The shell is phosphatic, relatively tliin, elongate, resembhng in tins respect Lingulella acutangula (Roemer) (PL XVII). From this it appears that we have in the Olenellu^ fauna of the Lower Cambrian, associated -with Obolella, a typical representation of the genus Lingu- lella. This association shows that the differentiation in the group of brachiopods represented by Lingula and Obolella, or the LinguUdse, had advanced a long way before the period in Lower OBOLID/E. 473 Cambrian time represented by the fauna at Troy, New York. It is to be borne in mind that the fauna at Troj^ was collected both from stratified and conglomerate limestones. On this account it is not practicable to state that all the species from either are from the same geologic horizon, but Lingulella scliuclierti (Walcott) (PL XXI) and Oholella crassa (Hall) (PL LIV) occur in the same pieces of limestone. Lingulella granvillensis Walcott (PL XXII) occurs at numerous places in Wasliington County, New York, in strata near the top of the Lower Cambrian zone. Lingulella nathorsti Linnarsson (PL XXXI, figs. 1, la-b) occurs in the Hohnia kjerulji zone of Sweden. It has nearly the outlme of Lingulella acutangula (Roemer) in some examples of the ventral valve. (Compare PL XXXI, fig. Ic, with PL XVII, fig. la; and PL XXXI, fig. la, with PL XVII, figs. Ih-k; also fig. 1 on each of the two plates.) Lingulella delgadoi Walcott (PL XXIX, figs. 6 and 6a) from the Olenellus zone of Portugal is, from our present knowledge of it, a true Lingulella. Matthew [1903, p. 109] in speakmg of the growth of Lingulella and allied forms, speaks of a law that the young shells are often round and the adults more elongate. This is in accord with the view that the protegidum of all forms of the Atremata is semicircular or semielliptical. In Lingulella (Lingulepis) gregwa (Matthew) (PL XLIV) and L. (L.) exigua (Matthew) (PL XLIII) the young shells are more elongate than the adult, owing to the broadening of the anterior portions of the valves as they increase in size. Lingulella ? paliformis [Hall and Clarke, lS92c, PL II, figs. 6-8] has the form of some of the more acuminate species of Lingulella, but from a study of the type specimens I am led to conclude that the material is too lunited to decide the true generic relations of the species. The area of the dorsal valve is hke that of Lingulella, but the only specimen showing the area of the ventral valve suggests that the pedicle furrow was confined to the dorsal valve. Nothing is known of the interior markings of either valve. The vertical range of Lingulella is from the upper horizon of the Olenellus or Lower Cambrian fauna to the summit of the Cambrian and into the Ordovician fauna. One of the oldest kno^vn species is Lingulella scliuclierti (Walcott) , found in the limestone conglomerate at Troy, New York, in association with Oholella crassa (Hall), Bicia gemma (Billings), Elliptocephala asa- pTioides Emmons, etc. Lingulella granvillensis Walcott, which is associated with Olenellus in the strata referred to the upper portion of the Olenellus zone, L. nathorsti Lumarsson of the Holmia Icjerulfi zone of Sweden, and L. delgadoi Walcott are found in association with Olenellus. The greatest development of the species is in the Middle and Upper Cambrian, only a few forms continuing on into the Lower Ordovician. The small Lingulella desiderata ranges from the base of the Middle Cambrian in the Cor- dilleran I'egion to the Ordovician. There may be specific differences, but in the large amount of material now available for study there are none that appear to be of specific importance. Lingulella isse also has a great vertical range. Lingula attenuata Sowerby [Davidson, 1866, p. 44, PL III, figs. 18-27] has the form oi_Linr- gulella and may possibly be a survival into the Middle Ordovician of a species of the genus. We do not have sufficient data to know whether the interior markings of the valves are more like those of Lingula, or Lingulella. Of the 77 species and 4 varieties from the Cambrian referred to Lingulella in this monograph, 5 species occur in the Lower Cambrian, 46 species and 1 variety in the Middle Cambrian, 35 species and 3 varieties in the Upper Cambrian, 6 species in the passage beds between the Cam- brian and the Ordovician, and there are 13 species fi-om the Ordovician. Of the Mddle Cam- brian species 13 pass up into the Upper Cambrian, of which two are found in the Ordovician. Two species pass from the Upper Cambrian to the Ordovician and two from the Upjjer Cambrian to the passage beds. The range of all known species is given in the tables of genera and species (pp. 98-113). Subgenera of Lingulella. — Leptemholon Mickwitz [1896, p. 199] is rather difficult to charac- terize. Mickwitz [1896, p. 199] says of it: The subgenus Leptemholon is based on a species of Obolus whicli externally resembles Lingula very closely, and in fact was regarded as sucli by earlier authors [Schmidt, Fr., 1881, p. 17]. The specimens of the internal surfaces 474 CM'IBKIAN BKACHIOPODA. of the valves, however, showed, together with some suggestions of the last-mentioBed genus (Lingula), unmistakable marks of the genus Obolus, so that the species, which would not be assigned to any of the other groups, had to be ranked in a special subgenus of Eichwald's genus. Type. — Oholus (Leptemholon) lingulxformis Mickwitz (PI. XIV, figs. 5, 5a-b). Lingulepis Hall [1S63, p. 129] is a Lingulella-hke shell with the ventral beak much atten- uated. Type: Lingula acuminata Conrad. For the species hitherto referred to Lingulella that are now referred to other genera or subgenera see pages 58-62. Lingulella acutangula (Koemer). Plate XVII, figures 1, la-o. Lingula acutangula Roemer, 1849, Texas, p. 420. (Described in Latin and discussed in German as a new species.) Lingula acutangula Roemee, 1S52, Ki'eidebildungen von Texas, p. 90, PI. XI, figs. lOa-b. (Described in Latin and discussed in German.) Lingulepis acutangulus (Roemer), Schuchert, 1897, Bull. U. S. Geol. Siu-vey No. 87, p. 259. (Merely changes generic reference.) Obolus (Lingulella) acutangulus (Roemer), Walcott, 1898, Proc. U. S. Nat. Mus., vol. 21, pp. 392 and 394; PL XXVII, fig. 6; PL XXVIII, figs. 1 and 2. (Mentioned in the text in discussion of Lingulella. Figs. 6, 1, and 2 are repro- duced in this monograph, PL XVII, figs. Ic, If, and Ih, respectively.) General form elongate ovate with the ventral valve subacuminate and the dorsal valve ovate in outline. When the ventral valve is slightly compressed the cardinal slopes are often crushed down over the area about the pedicle groove, so as to make the outline of the valve more acuminate. This appears to be the case with the type figure of Roemer, and it is partly shown by Plate XVII, figure le. There is considerable range of variation in the outline of the valves (PI. XVII) . The convexity of the two valves is fairly strong, and it is nearly the same in each, except that the dorsal valve curves inward more rapidly toward the beak. A ventral valve 9 mm. in length has a convexity of 1.25 mm., and a dorsal valve 10 mm. long arches 1.5 mm. above the plane of the margin. Surface of the shell marked by radiating and concentric striae and lines of growth. The radiating striae are usualty indistinct, but in a number of shells they are well marked or inter- rupted somewhat by irregular rounded lines that alternate, blend, and disappear without any apparent system (PI. XVII, fig. 1 1) . The concentric stride are fine, usually having an unbroken curvature, but in some instances they are broken into short undulations, such as characterize the surface of several other species of Lingulella. In some examples the undulations are close and pronounced, and form a fine broken reticulation that is discernible only with a strong mag- nifying glass. When the outer layer of the shell is partly exfoliated the radiating striae appear as sharp, clear-cut lines, but they do not extend to the inner surface of the shell (PL XVII, fig. 1 1). The interior surface is usually marked by strong punctae which vary greath' in number and arrangement. This is illustrated by the casts of the interior of several shells, where the punctse are represented by papillae. On figure Ic the papillae are large and somewhat scattered, while in figure la they are smaller and arranged in concentric lines quite to the edge of the shell. In the dorsal valve the punctae are not quite so strong and they do rtot extend out to the margin (PL XVII, figs, li, Ij, and Ik) ; in specimens showing the interior scars and markings the punctse are less numerous (figs. If, Ih, and Ij). The shell is thicker than in most species of the genus, in this respect resembling in a modified degree the type of Oholus, 0. apollinis Eichwald. The shell is formed of a thm outer layer and several thinner layers or lamellae that are slightly oblique to the outer laj^er (fig. Im), a structure quite similar to that of the shell of the recent Lingula anatina Bruguiere. The longest ventral valve in the collection has a length of 14 mm., and a maximum width of 10 mm. Roemer's figure [1852, PL XI, fig. 10] is larger, 18 mm. by 13 mm. The average length of the ventral valve is from about 8 to 10 mm., and of the dorsal valve 6.5 to 8.5 mm. The relative dimensions of the two valves may be seen b}^ a comparison of figures 1 and li, Plate XVII. OBOLID^. 475 As determined by a stud}" of interior casts, the plane of the cardinal area of the ventral valve coincides near its edges with the edge of the shell, rising slightlj- toward the deep, rounded pedicle furrow. The area is divided at the center by the pedicle furrow, and toward its margins by elevated lines, or extremely narrow ridges, that extend from the apex with a slightly- outward curvature to the base of the area (the flexure marks of the area parallel with its base) ; they are rounded and strong in the pedicle groove, sharp and crowded on the lateral slopes; they cross the pedicle groove transversely, slope forward across the central spaces (splanchnoccele of Mickwitz [1896, p. 116]) curve almost backward in the flexure lines and slope forward at a low angle across the lateral spaces (pleurocoele of IMickmtz [1896, p. 116]). The area forms a thin shelf between the pedicle groove and the lateral margins, the undercut extending far back under the area. This is shoAvn in the cast by a tliin projection of the embedding rock over the area (PI. XVII, figs la, Ic, and If), where the broken edges remain. The area of the dorsal valve is lower and less prominent; the striae of growth cross it parallel to the anterior margin, being interrupted by the flexure lines, which are but shghtly indicated on most specimens. The shallow furrow, corresponding to the pedicle furrow of the ventral valve, usually extends across the space between the flexure lines. The pedicle groove on the ventral valve is deep, narrow, and strongly defined, tapering very gradually from the anterior end toward the beak. The cast of the visceral cavity (v), including the heart-shaped pit (x) of the ventral valve, is shown by Plate XVII, fig-ures la, Ic, If, and Ig, the latter particularly well by figure If, where it strongly resembles the same space in Oholus apollinis Eichwald. There are no traces of a median septum in the ventral valve ; in the dorsal valve it is shown in the casts as a very narrow, clearly defined, sharp depression (s) extending a short distance back of the central muscle scars, in some specimens, and forward nearly to the anterior lateral scars (PI. XVII, figs. Ih and Ij). • The muscle scars are finely shown in casts of both valves. The umbonal scar (gg) of the ventral valve is divided as in Oholus, the pedicle scar (m) being situated between the two parts (PI. XVII, fig. If) ; the latter are oval in outline, their longer axis being slightly inclined forward and outward. In the dorsal valve the umbonal scar (g) is very close to the area and extends across nearly the entire distance between the central portion of the area delimited by the flexure lines (PI. X'Sni, figs. Ih and Ij). In one specimen fine striae cross the scar subparallel to the median Ime of the shell. The scars of the central muscles are not clearly defmed in the ventral valve, owing to their being crowded in with the scars of the middle and outside laterals. Their position, judging from the location of the centrals in Oholus, is ^\^.thin the trapezoidal area (c) indicated on Plate XVII, figures If and Ig. The central muscle scars (hh) are large and distincth^ defined on a number of casts of the interior of the dorsal valve. They are situated a little in advance of the center of the shell, on each side of the median septum, with their longer axis inclined ou tward at an angle of nearly 45° (PI. XVII, figs. Ih and Ij). The anterior laterals (j) are clearly defined in both valves; their form, size, and position are shown by figures If and Ig for the ventral valve, and figures Ih and Ij for the dorsal valve. The middle and outside lateral scars on the ventral valve are situated in the trapezoidal area (c), but neither are clearly separable in an}' of the specimens in the collection unless it be in that represented by figure Ic, where a small round scar (k) occurs, corresponduig in position to that of the middle lateral scars of Oholus. On the dorsal valve the middle and outside laterals are closely united as in Oholus, and they are apparently combined in the elongate scar (1) (PI. XVII, figs. Ih and Ij). This scar corre- sponds in position with the two scars in Oholus, in which genus it is usually impossible to dis- cover the line of demarcation between them. The transmedian scars (i) are distmctly shown on the dorsal valve (PL XVII, figs. Ih and Ij), but in the ventral valve they are so closely united with the anterior laterals (j) that it is impossible to differentiate them. Portions of the markings left on the shell by the vascular system are finely preserved in a few casts of the interior of the valves. The description is of the present appearance of the casts, which is the reverse of the actual condition in the interior of the shell. The main or trunk 476 CAIIBKIAN BRACHIOPODA. sinuses (ts) are inclicated for the ventral valre in figure Ig, and for the dorsal valve b}- figures Ih and Ij. The latter are rather indistinct, rounded ridges, \nth a few lateral branches sho^\^ng in the specimens. In figure Ig the interior lateral branches (ivs) are shown, and the peripheral sinuses (pvs) are seen m figures Ih and Ij, Plate X^^I. The parietal scar (ps) is cUstinctly shown in front of the visceral area of the ventral valve (PI. X^T^I, fig. If), but it has not been traced outside of the mam sinus. In one specimen of the dorsal valve its course may be followed from the median line in front of the anterior lateral muscle scars, cui"ving outward to the main vascular sinus and outside of the sinus around the outside lateral, where it turns back toward the flexure line of the area (fig. Ij). Oiservations. — The specimens described bj^ Roemer [1S49, p. 420] came from a limestone in San Saba County, Texas. He figures [1852, PI. XI, fig. 10] a ventral valve that is larger and more acuminate than the majority of the specimens in the collection before me; but, in the absence of a closely alhed species from the Cambrian of Texas, and in view of the fact that there is a considerable range of variation in the form of the valves, I do not hesitate to identify the form here described as belonging to the species studied by Roemer. He compares it [1852, p. 90] with "Lingula cuneata" of the Medina sandstone of New York, to point out that it is more acuminate than that species. It also differs from it in the character of the interior markings and muscle scars and the greater thickness of the shell. Prom other species of the genus, Lingulella acutangula varies in form and in the arrangement of the muscle scars. It is some- what closely related to Lingulella cuneola (Whitfield) of the iliddle Cambrian of the Black Hills, South Dakota, and the latter species may even be identical with it. Formation and locality. — Tipper Cambrian: (14b) Limestone on Cold Creek at north end of gorge opposite the north end of Sponge Mountain, 2 miles (3.2 km.) south of the San Saba County line, in Llano County; (14i) upper part of the limestone exposed 1 mile (1.6 km.) west of Cherokee, San Saba County; (353) limestones [see Roemer, 1849, p. 420] on San Saba River, San Saba County; (68 and 68e) interbedded limestone and sandstone, Packsaddle Mountain, Llano County; (69) limestone, near Honey Creek, Burnet County; (67 and 67c) sandstone on Tatur Hill, 7 miles (11.2 km.) northwest of Burnet, Burnet County; (353c) heavy dark ferruginous sandstone collected somewhere in Llano County; and (70 and 70e) limestone, near Morgans Creek, Bm-net County; all in Texas. Middle Cambrian: (llj) Basal part of Bonneterre limestone. Mine Lamotte, Madison County; and (Ilk) limestones of the "Edgewise beds," beneath the Elvins formation, St. Francois County; both in Missouri. (17c) Sandy limestone, 235 feet (71.6 m.) above the "Tonto" sandstone, Grand View trail, north of Last Chance copper mine, south side of the Grand Canyon of the Colorado, Arizona. Specimens that are somewhat doubtfully referred to Lingulella acutangula occur at the f oUowmg locahties : TTpper Cambrian: (327) Arenaceous limestone east of Gold Camp, in the Caballos Mountains, Sierra County, New Mexico. (Ill) Arenaceous limestone of the El-vins formation, 50 feet (15.2 m.) above the "Edgewise beds," St. Francois County, Missouri, Middle? Cambrian: (313c) Limestone 12 miles (19.3 km.) west-southwest of Alpha Station, Eureka County, Nevada. Lingulella agnostorum (Wallerius). Plate XXX, figure 15. Lingula agnostorum Wallekius, 1895, LTndersokningar ofver Zonen med Agnostus lievigatus i Vestergotland, pp. 64-65, figs. 8a-b. (Described in Latin, and discussed in Swedish, as a new species.) Shell very small. Outline ovate, with the ventral valve subacuminate ; moderately convex. Surface of shell marked by concentric striae and strong growth lines that, near the umbo, form deep undulations separating the mmute, elevated, smaller umbo from the less elevated con- centric ridges in front of it. The ventral valve illustrated hj Wallerius is about 3 nnn. in length and that of the specimen before me is 1.5 mm. I have not seen a dorsal valve. Ohservations. — This minute shell is associated with Acrotreta parvula (Wallerius) and Agnostus lievigatus. It differs from Lingulella sp. undt. a of the Olenus truncatus zone in its minute size, more acute beak, and less distinctly striate surface characters. OBOLID^. 477 This form owes its specific name to its association with Agnostus. Formation axd locality. — (310i) Limestone in passage beds between the Middle Cambrian Paradoxides forch- hammeri zone and the Upper Cambrian Olenus truncatus zone; at Borgholm, on Oeland Island, Sweden. LiNGTILELLA AMPLA (Owen). Plate XXVIII, figures 1, la-j. lAngula ampla Owen, 1852, Rept. Geol. Survey Wisconsin, Iowa, and Minnesota, p. 583, PL I b, figs. 5 and 12. (Described as a new species, see p. 478 for copy. The specimen represented by fig. 5 is redrawn in this mono- graph, PL XXVIII, fig. 1.) Lingula ampla Owen, Hall, 1863, Sixteenth Rept. New York State Cab. Nat. Hist., p. 125, PL YI, fig. 10. (Original description, Owen, 1852, p. 583, copied and species discussed.) Lingula ampla Owen, Hall, 1867, Trans. Albany Inst., vol. 5, pp. 101-102, PL I, fig. 10. (Discussion and figure copied from preceding reference.) lAngulella ampla {Ovf en), Schuchert, 1897, Bull. U. S. Geol. Survey No. 87, p. 257. (Merely changes generic reference.) Obolus (Lingulella) amphis (Owen), Walcott, 1898, Proc. U. S. Nat. Mus., vol. 21, pp. 392 and 394, PL XXVIII, figs. 3-4. (Mentioned in the text in discussion of Lingulella. The specimens represented by figs. 3 and 4 are redrawn in this monograph, PL XXVIII, figs. If and Ih, respectively.) General form ovate, with the ventral valve obtusely acuminate and dorsal valve broadly ovate; valves moderately convex. Surface of shell marked by concentric striae, and lines of growth and indistinct radiating strife; verj^ fine radiating stri^ occur on the inner surface of the outer layer of the shell, and the casts show the presence of papillae that indicate that the inner surface of the shell was punctate (PI. XX"\T;II, fig. Ig). The shell is of medium thickness and formed of a thin outer layer and several inner layers or lamellae which give a greater thick- ness to the posterior half. The lamella are arranged as in Lingulella acutangula (Roemer) where they are slightly oblique to the outer layer. One of the larger ventral valves has a length of IS mm., mth a maximum A\'idth of 12 mm., and an associated dorsal valve has a width of 12 mm. and a length of 15 mm. As shown ia the cast of the interior of the shell, the area of the ventral valve is nearly flat near its lateral margin and lises from about the flexure line toward the pedicle groove. The pedicle furrow is shown by a narrow, elevated, rounded, tapering ridge which divides the area midway. The area is marked also by rather strong flexure Imes which extend from the beak obliciuely across the area at some cUstance from the outer margin, as shown in Plate XXVIII, figures Ic-f. The strife of growth cross the area parallel \ni\\ its base; they are very fine and closely grouped together on the lateral slopes; none of the specimens show their presence on the cast of the pecUcle furrow. The area forms a thin shelf between the pedicle groove and the lateral margins, the undercut extending backward far under the area. This is well sho^^■n in several of the casts, although the cast of the undercut is usuallj' broken away. A portion of it remains, however, in Plate XX\1II, figure Ic. The area of the dorsal valve is well defined and is marked in one specimen b}^ strong flexure lines (f, fig. Ih), and fuie transverse striffi. As in the ventral valve, the area forms a thin shelf, the cast of the undercut extending well imder the area in several of the specimens. Its ragged edges are shown in figure li. The cast of the interior of the ventral valve shows the visceral cavity (v), and there are slight traces of a median septum (s) in the dorsal valve (PI. XXVIII, fig. Ih). The muscle scars are partly preserved. In the ventral valve the anterior laterals (j) are shown in one cast (PI. XX\T!II, fig. Ic). The central, middle lateral, and outside lateral muscle scars are all crowded together and lost m the space in front of the anterior portion of the visceral cavity. The central (h) and anterior lateral (j) muscle scars are well defined in the dorsal valve (PL XX^TCII, figs. Ig and Ih). Of the markings left on the cast by the vascular sj'stem onh' the main smus (vs) is pre- served (PI. XX"\TII, figs. Ic, Id, and If for the ventral valve and figs. Ig and Ih for the dorsal valve). Observations. — One of the specimens illustrated by Owen [1S52, PL I b, fig. 5] is in this monograph represented by Plate XXWII, figure 1. It appears to be a ventral valve that 478 CAilBRIAN BRACHIOPODA. has been broken away toward the apex. His second figure [1852, PI. I b, fig. 12] is a partially covered dorsal valve which shows the characteristic form and the concentric striae of the species. His description [1852, p. 583] is as follows: This species has a greater chcumference and superficial area than any of the others hitherto discovered in F. 1. Shell nearly oval, rather flat; beak blunt, and not projecting beyond the general contour of the shell, and formed more after the manner of the beaks of TerabratuliE. A few faint concentric strite. Length 11/16 of an inch; width 8/16 of an inch. This species occurs in the Lingula and Obolus grits, member c, near Mountain Island, at the Dalles of the St. Croix, and elsewhere in Wisconsin. James Hall did not have the type before him when he described the species. He identified a form from the lower bed at Trempealeau, which he regarded [1863, p. 125] as the typical form of the species. The original type came from Mountain Island, in the Mississippi just above the mouth of Trempealeau River. It also occurs at about the same horizon 10 miles lower down on the west shore of the river, opposite the mouth of Black River. In general form, this species somewhat resembles Lingulella lillingsiana (Wliiteaves) from Newfoundland, but it differs from that species in the character of the surface markings and that of the interior markings and scars, especially those of the dorsal valve. The position of the main vascular sinus of the dorsal valve distinguishes it from other si:)ecies of which we have the interior mark- ings. In a specimen of the ventral valve (PI. XXVIII, fig. If) there appears to be a unique marking (y) in the central anterior portion of the valve. It recalls the heart-shaped pit (x) of Obolus and Lingulella acutangula (Roemer) (PI. XVII, fig. If), but it is so far away from, the normal position of that pit that it appears to be the resultr of a malformation or an impression in the cast which accidentally resembles the outline of the heart-shaped pit. Formation and locality. — Upper Cambrian: "St. Croix sandstone" at the following localities: (80) 0.66 mile (1.1 km.) southwest of the railway depot at Menomonie, Dunn County; (100) near Menomonie, Dunn County; aiid (98) near Eau Claire, Eau Claire County; all in Wisconsin. Middle Cambrian: (84 and 84f) "St. Croix sandstone," at Dresbach opposite the mouth of Black River, Winona County; (84s) near Dakota, Winona County; and (339e) on Mountain Island, Minnesota, in Mississippi River just above the mouth of Trempealeau River; all in Minnesota. (338g) Wisconsin shore of the Mississippi, near Trempealeau, Trempealeau County; and (328e) "St. Croix sand- stone" at St. Croix Falls, Polk County; both in Wisconsin. A closely related if not identical species occurs at the following locality. A ventral valve from this locality is illustrated in Plate XXVIII, figure Ij. Middle Cambrian: (88a) Limestone about 100 feet (30.5 m.) above the quartzitic sandstone at the base of the Cambrian in the northern suburbs of Deadwood, Black Hills, South Dakota. Lingulella arguta (Walcott). Plate XXIV, figures 5, 5a-b. Lingula? manticula White (in part), 1874, U. S. Geog. Surveys W. 100th Mer., Prelim. Rept. on Invertebrate Fossils, pp. 9-10. (Described as a new species, including specimens referred to both Lingulella arguta and L. manticula.) Lingula ? mantiaila White (in part), 1877, U. S. Geog. Surveys W. 100th Mer., vol. 4, pp. 52-53, PI. Ill, fig. 2a (not fig. 2b). (Described and discussed. The specimen represented by fig. 2a is redrawn in this monograph, PI. XXIV, fig. 5. The specimen represented by fig. 2b is referred in this monograph to Lingulella manticula.) Obolus (Lingulella) argutv^ Walcott, 1898, Proc. U. S. Nat. Mus., vol. 21, p. 396. (Described and discussed as below as a new species.) General form ovate, with the ventral valve obtusely acuminate; valves moderately con- vex. Exterior surface of the shell unknown. Very fine radiating strise and concentric lines of growth occur on the outer surface of the inner layer of the shell. The shell appears to be of medium thickness and formed of a thin outer layer and one or more thin inner layers or lamellas. The type specimen of the ventral valve has a length of 6 mm. and a width of 4.5 mm. Observations. — This species is founded upon one of the specimens illustrated by White [1875, PL III, fig. 2a] as Lingula? manticula. The broadly ovate form of the ventral valve clearly distinguishes it from that species. From the associated fragments of trilobites it evi- dently occurs at a lower horizon in the Middle Cambrian. A dorsal valve from the same locality OBOLID^ 479 and in a slightly different character oi limestone is illustrated and provisionally referred to the same species (PI. XXIV, fig. 5a). In outline this shell resembles Lingulella bella (Walcott) and L. lellula (Walcott) from Newfoundland; it is more broadly acuminate than these species and much smaller than Lingulella hella. It may also be compared with L. punctata (Walcott) , from which it differs in being more ovate. Formation and locality. — Upper Cambrian : (313f) Limestone at Schellbourne, Sckell Creek Range, White Pine County, Nevada. Middle Cambrian: (3e) Thin-bedded limestone less tlian 400 feet (121.9 m.) above the quartzitic sandstones of the Cambrian, near Ophir, Oquirrh Range, Tooele County, Utali. (llw) About 1,050 feet (320 m.) above the Lower Cambrian and 3,350 feet (1,021.1 m.) below the Upper Cambrian in the shales forming Id of the Swasey formation [Walcott, 1908f, p. 182], at the head of Dome Canyon; (3w) about 2,350 feet (716.3 m.) above the Lower Cambrian, and 2,050 feet (624.8 m.) below the Upper Cambrian, in the central portion of the thin-bedded Kmestones forming Ic of the Marjum limestone [Walcott, 1908f, p. 180], in the cliff about 2 miles (3.2 km.) southeast of Marjum Pass; (lOy) about 2,900 feet (88"4 m.) above the Lower Cambrian and 1,500 feet (457.2 m.) below the Upper Cambrian in the central portion of the limestone forming la of the Marjum limestone [Walcott, 1908f, p. 179], about 1 mile (1.6 km.) south-southwest of Marjum Pass; (3x and llx) about 2,200 feet (670.6 m.) above the Lower Cambrian and 2,200 feet (670.6 m.) below the Upper Cambrian, in the limestones forming Id of the Marjum limestone [Walcott, 1908f, p. 180], 2.5 miles (4 km.) east of Antelope Springs, in ridge east of ^Vheeler Amphi- theater; and (llq and lly) about 2,350 feet (716.3 m.) above the Lower Cambrian and 2,050 feet (624,8 m.) below the Upper Cambrian, in the limestones forming Ic of the Marjum limestone [Walcott, 1908f, p. 180], 2.5 miles (4 km.) east of Antelope Springs, in ridge east of Wheeler Amphitheater; all in the House Range [Walcott, 1908f, Pis. XIII and XV], Millard County, Utah. (14m) Limestone about 7 miles (11.2 km.) south of Towner's ranch, Indian Creek, Lincoln County; (54) Eldo- rado limestone [Walcott, 1908f, p. 184], on the east slope of Prospect Mountain, in New York Canyon, Eureka district [Hague, 1892, Atlas], Eureka County; (59) limestone at the base of the western slope of Combs Peak, near the plain of jy.ntelope Valley, Eureka district [Hague, 1892, Atlas], Eureka County; and (313e) limestone 2 miles (3.2 km.) west of Green's ranch. White Pine County; all in Nevada. A shell which is provisionally referred to Lingulella arguta occurs associated with the latter species in the following locality: Middle Cambrian: (313a) Limestone at Schellbourne, Schell Creek Range, White Pine County, Nevada. Lingulella atava (Matthew). Plate XXXV, figures 5, 5a-h. Leptobolus atavus Matthew, 1899, Bull. Nat. Hist. Soc. New Brunswick, vol. 4, pt. 3, No. 18, pp. 200-201, PI. II, figs., la-b and d-f. (Described and discussed as a new species. The specimens represented by figs, la and Id are redrawn in this monograph, PI. XXXV, figs. 5 and 5c, respectively.) Oholus (Lingulepis) gregioa Walcott (in part) [not (Matthew)], 1901, Proc. U. S. Nat. Mus., vol. 23, pp. 692 and 694. (Matthew's "Leptobolus atavus" mentioned as the young of "Lingulepis gregwa.") Oholus (Lingulella) atavus (Matthew), Walcott, 1902, Proc. U. S. Nat. Mus., vol. 25, pp. 609-610. (Described and discussed essentially as below.) Leptobolus atavus Matthew, 1903, Geol. Survey Canada, Rept. Cambrian Rocks Cape Breton, pp. 106-109, PI. VI, figs. 2a-b and d-g. (Described and discussed. Figs. 2a-b, d-e, and g are copied from Matthew, 1899b, PI. II, figs, la-b and d-f, respectively.) General form elliptical, with the ventral valve subacuminate, and the dorsal valve broadly subacuminate in outline. In the shorter form of the valves the sides are almost uniformly rounded from the cardinal slopes to the frontal margin. The convexity of the valves is fairly strong, that of the dorsal valve being broken by a slight longitudinal flattenmg that extends from the posterior portion to the frontal margin. As shown by the matrix, the outer surface is marked by concentric ridges and fine striae of growth. The interior cast shows concentric lines and traces of rather coarse radiating Imes. None of the specimens preserve the shell, but from the strength of the interior surface markings it is inferred that the shell was rather thick. The longest ventral valve in the collection has a length of 6 mm.; width, 3.5 mm. The dorsal valves are slightly shorter. The area of the ventral valve is divided at the center by a strong pedicle furrow, and about midway between the pedicle furrow and the outer margin by clearly marked flexure 480 CAjMBRIAN brachiopoda. lines that extend from the apex, with a slightly outward curvature, to the base of the area. Strife of growth cross the area parallel with its base, being much stronger on the area than in the pedicle furrow. The area of the dorsal valve is fully as prominent as that of the ventral valve. It curves forward at the center and extends well out on the cardinal slopes. The flexure lines are clearly defined well out toward the lateral margin. The striae of growth cross the area parallel to the base. The cast of the interior of the ventral valve shows only the outline of the visceral cavity, and that the main vascular sinuses extend a considerable distance in advance of the visceral cavity. The cast of the interior of the dorsal valve shows that it had a strong, broad, central ridge, divided by a faint longitudinal median sinus. Only traces have been seen of the main vascular sinuses. Observations. — This is a very pretty little species that, in the absence of well-defined speci- mens, I [1901, p. 694] confused with the young of "Lingule-pis gregwa" Matthew. Material collected by S. Ward Loper at the type locality, however, proves that the shell differs consider- ably from that of the young of Lingulella (Lingulepis) gregwa, although specimens of the dorsal valve of the two forms are often very much alike. Matthew's illustrations [1903, PI. VI, figs. 2a-b, d-g] of Lingulella atava are somewhat diagrammatic, as though they were drawn to represent the average form of several specimens. With the type specimens before me I find considerable variation in width and outline. Some have the outline of Lingulella eoUieia (Matthew) and the two types of the latter species are much like Matthew's figures of Lingulella atava [1903, PI. VI, figs. 2a-b, d-g]. The specimens of Lingulella collicia have the rotund, subquadrate outline of Lingulella atava and not the uniform curvature of j\Iatthew's figures of Lingulella collicia [1903, PI. VI, figs. 3a, 3b]. With a large series of well-preserved material from the type locahty and formation, I have endeavored to represent two forms that may be referred to Lingulella atava and Lingulella collicia, respectively. Lingulella atava is more slender and its sides are more uniformly curved than L. collicia, and it is also usually larger. Lingulella cania (Walcott) is a narrow, elongate form. Formation and locality. — Middle Cambrian: (lOp) Sandstones just below the waterfall in Division E2b; (13d and 13d') sandstones opposite the third waterfall, between Divisions E2a and E2b; (131') sandstones of Division E3a; (344) sandy shales of Division E3b; (13n" and 344b) sandstones of Division E3d; (13n')a sandstones of Division ESe; and (13n and 344d) sandstones of Division E3f ; all in Matthew's [1903, p. 21] Etcheminian, on Dugald Brook, Indian River, eastern Cape Breton, Nova Scotia, Canada. Lingulella atava iNstTLiE (Matthew). Plate XXXV, figures 8, 8a. Leptobolus atavus insulx Matthew, 1903, Geol. Survey Canada, Kept. Cambrian Rocks Cape Breton, pp. 110-112, PI. VI, figs. 4a-c. (Described and discussed as a new variety. The specimens represented by figs. 4a and 4b are redrawn in this monograph, PL XXXV, figs. 8 and 8a, respectively.) The form of this shell is much like that of Lingulella cania (Walcott) or a narrow L. atava (Matthew). The material representing it is not well preserved. Matthew [1903, PL VI, figs. 4a-c] has illustrated it with three somewhat diagrammatic figaires that give his conception of its form and interior markings. I have figured two of the best preserved of the tj^jical specimens. Thej^ show the general form and character to be similar to those of L. atava. Formation and locality.— Middle Cambrian: (307d [Matthew, 1903, p. 110]) Sandstones believed to belong to Division E2a of Matthew's Etcheminian, at Youngs (McFees) Point, George River, eastern Cape Breton, Nova Scotia. LiNGtJLELLA AUGA (Walcott). Plate XXIV, figures 6, 6a-g. Obolus (Lingulella) auga Walcott, 1898, Proc. U. S. Nat. Mus., vol. 21, pp. 396-397. (Described as below as a new species.) General form subcuneate, with ventral valve obtusely acuminate, and the dorsal valve rounded acuminate; valves moderately convex. Surface of the shell, as indicated by casts a 13n' is the type locality, though the specimens in the United States National Museum collections to which that number is assigned were collected later than the type specimens. Localities 344, 344b, and 344d are cited by Matthew (see pp. 208-269). OBOLID^. 481 in the fine sandstone, marked by lines of growth, and fine, slightly undulating strise.; the inner surface is marked by somewhat irregularly scattered pits or punctse, some of which are unusually large for the size of the shell. The few remaining traces of the shell indicate that it was relatively thin. The largest well-preserved cast of the ventral valve has a length of 5 mm., with a width of 4.5 nun. The dorsal valves are a little shorter, the length and breadth being nearly the same. Casts of the interior of the ventral valve show the presence of a rather long area divided midway by a narrow, clearly defined cast of a pedicle groove; traces of flexure lines are also preserved. The area of the dorsal valve is proportionately shorter than that of the ventral valve; traces of the visceral cavity (v) and the base of the main vascular sinuses (vs) are pre- served in a few specimens and in one specimen the anterior lateral muscle scars appear to be present. Observations. — In the form of the valves this species is somewhat similar to Lingulella grandis (Matthew) (PI. XXXVIII); otherwise it appears to be quite distinct from any other described species. It has a long cardinal area and a narrow, deep pedicle furrow on the ventral valve. Formation and localitt. — Middle Cambrian: (10a) Sandstones of the Rome formation, in west railroad cut Ijirough Shooks Gap; and (10b) limestones of the Rome formation at the western end of the central railroad cut through Shooks Gap; both in Bays Mountains, 10 miles (16.1 km.) southeast of Knoxville [Keith, 1895, areal geology sheet], Knox County, Tennessee. LlNGTILELLA BELLA (Walcott). Plate XIX, figures 2, 2a-q; Plate XXXVI, figure 4. Obolus (Lingulella) bellus Walcott, 1898, Proc. U. S. Nat. Mus., vol. 21, pp. 397-398. (Described and discussed as a new species.) Obolus {Lingulella) bellus Walcott (in part), 1901, Proc. U. S. Nat. Mus., vol. 23, pp. 685-687. (Described and dis- cussed, including specimens now referred to Lingulella concinna Matthew and L. lens (Matthew).) Obolus {Lingulella) bellus Walcott, Matthew, 1903, Geol. Survey Canada, Kept. Cambrian Rocks Cape Breton, p. 204. (Says "0. {L.) bellus" does not include "Lingulella concinna" .) General form ovate, with ventral valve obtusely acuminate, and dorsal valve broad ovate to ovate quadrate; valves moderately convex as far as can be determined from the somewhat compressed specimens as they occur in the sandy shales. The small ventral valves are more acuminate than the large ones and the smaller dorsal valves are more elongate. The change in form is slight from one to another specimen in the series, but the two extremes are so different that without the connecting series two species could be determined. Surface of shell with numerous concentric lines of growth and fine radiating lines. The inner layers are marked by concentric lines and numerous fine radiating strise. The shell is relatively thin over the anterior portions and stronger near the cardinal mar- gins. It is formed of a very thin outer layer, with one or more thin layers or lamellse. The casts of the interior surface of the ventral valve show numerous papdlse arranged in concentric lines on the posterior half of the shell. These correspond to the punctse of the inner surface. A large ventral valve has a length of 22 mm.; width, 15 mm.; and a dorsal valve 18 mm. in length had a width of 14 mm. The specimens in the collection average from 2 to 3 mm. smaller than those measured. The cast of the area of the ventral valve shows that it was rather long and extended well ' out onto the cardinal slope; it is divided midway by a strong pedicle furrow, and toward the lateral margin by a narrow fiexure line. The area is marked by fine strise of growth parallel to the margin. The area of the dorsal valve is rather short, but it extends laterally well out on the cardinal slopes. The shallow curve corresponding to the pedicle groove of the larger valve is wide and clearly defined. The casts of the interior of the valves show almost no traces of the vascular markings or muscle scars. Only the central and anterior lateral muscle scars and the main vascular sinuses have been observed in the ventral valve. 62667°— VOL 51, pt 1—12 31 482 CMIBKIAN BRACHIOPODA. Observations. — This fine species occurs ia great abundance in the upper beds of Little Belle Island associated with a narrow form of Lingula; and also in the higher beds on Great Belle Island, and a little below the layers carrying Oholus (lAnguloholus) affinis (Billings) and 0. (L.) spissus (Billings). The species is found at some little distance above the horizon in which I collected a species of Olenus and I refer the horizon to the Ordovician or the passage beds to the Ordovician fauna. The species appears to be clearly distinct from any described form. It may be compared with Lingulella davisi (McCoy) in relation to its size and outline, but not in other respects. It differs in the size and position of the muscle scars and the more strongly punctate interior surface. Some of the smaller shells closely resemble Lingulella concinna Matthew and the larger ones L. lens (Matthew). ^Vhen studying the material of the two latter forms in 1901, I referred them all to Lingulella hella [Walcott, 1901, p. 685], but with the large series now before me this reference is not sustained. Formation and locality. — Lower Ordovician: (114b) Sandstone 1 mile {1.6 km.) varth of Lance Cove, Great Belle Island, Conception Bay, Newfoundland. Upper Cambrian : (114 and 114a) Uppermost sandstone beds and the sandy shales underlying them on Little Belle Island, in Conception Bay, Newfoundland. (343b) Limestone pebble on Sachuset Beach, near Newport, Narragansett Bay, Rhode Island. Lingulella bellxjla (Walcott). Plate XIX, figures 1, la-e. Oholus {Lingulella) bellulus Walcott, 1898, Proc. U. S. Nat. Mus., vol. 21, p. 398. (Described and discussed as below, as a new species.) Oholus {Lingulella) bellulus Walcott, Matthew, 1903, Geol. Survey Canada, Rept. Cambrian Rocks Cape Breton, p. 205. (Says this species and "Lingula billingsana" Whiteaves are the same.) General form ovate with the ventral valve obtusely acuminate; dorsal valve round ovate; valves moderately convex. Surface of shell marked by concentric lines of growth and exceed- ingly fine, irregular striae that give the same appearance to the surface as that seen on Oholus (Westonia) ella (Hall and Wliitfield), Oholus fragilis (Walcott), and on a larger scale on Lingulella radula Matthew. The outer layer of the shell usually adheres to the arenaceous matrix, leaving the shiny inner layer on the shell; this is marked by concentric stride and lines of growth, and fine radiating stri^. The shell is thin and formed of a very thin outer layer and one or more thin inner layers or lamellse. The average length of the ventral valve is -from 4 to 5 mm.; width, 3 to 3.5 mm. The dorsal valves are a little shorter, 0.5 mm. to 1 mm. The cast of the area of the ventral valve shows it to be elongate, divided midway by a narrow but strong pedicle furrow, and, about midway between the pedicle furrow and the lateral margin, by a narrow flexure line; it is marked by striae of growth parallel to its base. •The area of the dorsal valve is not well shown on the specimens in the collection. The cast of the interior of the ventral valve shows somewhat imperfectly the visceral cavity, but not the muscle scars. In an interior of the dorsal valve the main vascular sinuses (vs) are well shown (PI. XIX, fig. Id), also the median septum (s). The central muscle scars are faintly shown in one fragmentary interior of the dorsal valve. Observations. — This beautiful little species occurs in the arenaceous shales and thin-bedded sandstones of Little Belle Island, in association with the larger species Lingulella bella (Walcott). It is closely related to Lingulella ferruginea Salter, but differs somewhat in form and the more anterior position of "the visceral cavity in the dorsal valve." The species is the Upper Cam- brian representative of the Middle Cambrian species L. ferruginea. It occurs at about the same horizon as L. billingsiana (Whiteaves) , but differs decidedly from it in form and convexity, the only points of comparison which the material permits. Formation and locality. — Upper Cambrian: (114 and 114a) <» Uppermost sandstone beds and the sandy shales underlying them on Little Belle Island, Conception Bay, Newfoundland. " H4a is the type locality. OBOLID^. 483 LiNGTJI-ELLA BILLINGSIANA (Whiteaves) . Plate XXIX, figures 3, 3a. lAngula hillingsiuna Whitbaves, 1878, Am. Jour. Sci., 3d ser., vol. 16, p. 226. (Described, see below, as a new species.) Lingulella? hillingsana (WTiiteaves), Schuchert (in part), 1897, Bull. U. S. Geol. Survey No. 87, p. 256. (Merely changes generic reference and spelling of Whiteaves's Lingula billingsiana, cited above. Includes also reference to specimens now referred to Lingulella grandis.) Not Lingula billingsana Whiteaves, Matthew, 1903, Geol. Survey Canada, Rept. Cambrian Rocks Cape Breton, p. 205. (Mentions "Obolus (Lingulella) belluliis" Walcott as the same as "Lingula billingsana.") The original description by Wliiteaves follows : Shell small, very slightly convex, compressed at the sides; outUne elliptic ovate, narrowest behind; length nearly twice the width; margin of the valves widening convexly and gradually from the beaks to the center, or a little beyond it; front narrowly and evenly rounded. Surface marked by fine concentric striations and faint radiating Hnes. Internal markings unknown. Length, about two Hnes and a haU; width, one line and a half. Observations. — Through the courtesy of Prof. J. F. Whiteaves I have been able to study the type specimens of this species. Much to my surprise I find them to be distinct from the forms (Lingulella hella and L. hellula, PI. XIX) I cohected on Little Belle Island and Great Belle Island, Conception Bay, and those (Lingulella grandis (Matthew), PL XXXVIII) tentatively compared with the species by Matthew. The shell is more elongate and convex than that of Lingulella hella (Walcott). Two specimens of the ventral valve are illustrated (PI. XXIX, figs. 3 and 3a). No dorsal valves occur in the material available for study. The outer surface is exfoliated from all of the specimens so as to show the shiny surface of the inner layer described by Whiteaves [1878, p. 226]. One of the broken ventral valves shows a narrow pedicle groove. The specific name was given in honor of Mr. E. BiUings. Formation and locality.— Upper Cambrian: (314a [^^Tiiteaves, 1878, p. 226]) Shales on Kelleys Island, Concep- tion Bay, Newfoundland. Lingulella boenemanni (Walcott). Plate XXX, figures 18, 18a-c. Lingula atienuata Bornemann [not Sowerby], 1891, Nova Acta Acad. Caes. Leop.-Carol. Germanicse Nature Curio- sorum, Bd. 56, No. 3, pp. 437-438, PI. XIX (XXXIV), figs. 1-10. (Described and discussed in German, see below for liberal translation. Pigs. 10a, 4, 8, and 7 are reproduced in this monograph, PI. XXX, fio-s. 18 18a-c, respectively.) Oholus {Lingulella) bornemanni Walcott, 1901, Proc. U. S. Nat. Mus., vol. 22, pp. 687-688. (Described and dis- cussed essentially as below as a new species.) The original description by Bornemann follows: Shell oblong oval, sharply pointed toward the beak, marked with fine concentric stripes which are usually regular and also often marked with large, irregular, concentric folds. Faint radial or longitudinal striation usually appears distinctly on the surface in the center of the shell. At the vertex there is usually a distinct, straight, lono-itudinal impression. Shape exceedingly variable, often unsymmetric, short rounded-triangular or almost circular, or narrower and elongated, more or less arched or even flat. The long-extended specimens resemble Lingulella (Lingulepis) acuminata (Conrad); others agree perfectly with Murchison's original figures of Lingula atienuata; others again may be compared with Lingulella davisi (McCoy) and were at first placed with that species. The simultaneous occurrence in enormous multitudes and the numerous transition stages leave no doubt that all these forms belong to one species, and the average type of them fits best to Lingula atienuata Sowerby. Size, 2 to 9 mm. The state of preservation is best in the slates, yet there the specimens are mostly pressed flat. The specimens existing in great numbers in the sandstones often still exhibit their original arching, but the deHcate shells are ordinarily distorted in an irregular manner and poorly preserved. Bornemann [1891, p. 437] identified this species with Lingula atienuata Sowerby, on account of the resemblance in outline of many of the specimens. Other specimens closely resemble Lin^ gulella (Lingulepis) acuminata (Conrad) from the Middle and Upper Cambrian of North America. It is so improbable that a species of this character should persist from Middle Cambrian time to Middle Ordovician time that, notwithstanding the resemblance, I think it is better to 484 CAMBKIAN BRACHIOPODA. distinguish it from Lingula attenuata Sowerby [Davidson, 1866, p. 44] and give a specific name that will not lead to erroneous stratigraphic correlations. The Cambrian fauna of Sardinia is so distinct from that of other localities and the stratigraphic succession of the subfauna is so confused that I think it unwise to identify'' its species with described species unless the material is so full and well preserved that there is no doubt of their specific identity. The specific name was given in honor of Dr. J. G. Bornemann. Formation and locality. — Middle? Cambrian: (354) Yellowish-broion slates not far from the buildings of Canal Grande; {35ia) gi-ayish- white quartzitic sandstone in the valley of Gutturu Sartu; (354b) yellowish sandstone with Archxocyathus at Punta Pintau and elsewhere; all [Bornemann, 1891, p. 438] in the island of Sardinia, Italy. LlNGtJLELLA BUTTSI Walcott. Plate XXIX, figures 4, 4a-b. Lingulella buttsi Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, pp. 70-71, PL VIII, fig. 6. (Described and discussed as below as a new species. Fig. 6 is copied in this monograph, PI. XXIX, fig. 4.) General form elongate ovate, with the ventral valve bluntly acuminate and the dorsal valve a little more rounded on the posterior margin. Both valves rather strongly convex. The great- est convexity of the dorsal valve is at the umbo, and of the ventral valve along the central sec- tion. A ventral valve 12 mm. in length has a convexity of 2 mm., and a dorsal valve 8 mm. long arches 1.75 mm. above the plane of the margin. A narrow, median, slightly flattened, almost concave space that extends from the apex to the front margin occurs on the dorsal valve. The exterior surface of the shell is dull dark-bluish gray and the inner layers shiny bluish black. The outer surface is marked by concentric stride and lines of growth with a few indistinct radiating striae ; the striae on the dorsal valve bend sUghtly backward where they cross the median, flattened space. The inner layers have many concentric striae, also numerous fine radiating striae. The shell is built up of several layers or lamellae, so as to be strong in the umbonal region and thin toward the edges. The largest ventral valve in the collection has a length of 12 mm. and a maximum width of 9.5 mm. at the anterior third of its length; a dorsal valve 10 mm. long has a width of 7 mm. A partly exfoliated ventral valve indicates the presence of a strong ridge on each side of the visceral area somewhat similar to that in Lingulella acutangula (Roemer) (PI. XVII) . Observations. — This fine shell has the general outline of the group of small shells of which LiTigulella ferruginea Salter is typical. It differs from them in its large size and strong shell. AU of the larger species of Lingulella are either more acuminate or broader in outline. The material was collected by Mr. Charles Butts, of the United States Geological Survey, and I take pleasure in naming the species after him. Formation and locality. — Middle Cambrian: (90b) Conasauga limestone in cut on Louisville and Nashville Raiboad, near Woodstock; and (90c) Conasauga limestone near Kimbrel; both in Bibb County, Alabama. LlNGtJLELLA CANIA (Walcott). Plate XXXV, figures 3, 3a-d. Obolus (Lingulepis) gregwa Walcott (in part) [not (Matthew)], 1901, Proc. U. S. Nat. Mus., vol. 23, p. 694. (Speci- mens now referred to Lingulella cania are here mentioned as representing the young of Lingulella {Lingulepis) gregwa.) Obolus (Lingulella) canius Walcott, 1902, Proc. U. S. Nat. Mus., vol. 25, pp. 610-611. (Described as below as a new species.) Shell small. General form elongate oval, with the ventral valve slightly acuminate. In both the ventral and dorsal valve the shell narrows posteriorly, the front being broadly rounded. The convexity of the two valves is well marked, and it is nearly the same in each. Surface of the shell marked by fine concentric striae and a few lines of growth. When the outer shell is exfoliated fine radiating striae cross the fine concentric striae. The shell appears to be of moderate thickness and formed of several thin layers or lamellae. The largest ventral valve in the collection has a length of 5 mm. ; width, .3 mm. ; and a dorsal valve 4 mm. in length has a width of 2 mm. OBOLID^. 485 The area of the ventral valve is elongate, being nearly one-fifth the length of the shell. It is divided midway by a very distinctly defined pedicle furrow. The flexure line is just percep- tible about half the distance out from the pedicle furrow to the lateral margin. The area extends well forward on the cardmal slopes and is marked by strong striae of growth parallel to its base. The area of the dorsal valve is shorter than that of the ventral, and is marked by fine lines of growth and clearly marked flexure lines that extend from the apex forward on a line with the main vascular sinuses. The cast of the interior of the ventral valves shows a general outhne of the visceral cavity and the main vascular sinuses. Only the base of the main vascular sinus has been seen in the dorsal valve. Ohservations. — This veiy pretty little species occurs in association with Paradoxides. In my first study of the brachiopods collected by S. Ward Loper from Cape Breton I confused it [1901, p. 694] with the young of Lingulella (Lingulepis) gregwa (Matthew). By means of a larger collection made by Loper in 1901, I have been able to separate it from the young of the associ- ated Lingulella (Lingulepis) exigua (Matthew) and from somewhat similar species that occur at a lower horizon, Lingulella atava (Matthew) and L. collicia (Matthew). It dift'ers from both the latter species in having a more elongate oval outline. It differs from the young of Lingulella (Lingulepis) gregwa in being more regularly oval and m having the posterolateral margin curved instead of nearly straight. Formation and locality. — Middle Cambrian: (3i) Compact, fine-grained, thin-bedded, gray sandstone of the Paradoxides zone, on McLeans Brook, 1 mile {1.6 km.) east of McCodnim Brook and 1.5 miles {2.4 km.) west of Marion Bridge; and (10s) sandstone on McLeans Brook, near Marion Bridge; both in eastern Cape Breton, Nova Scotia, Canada. Lingulella cedens (Barrande) Plate XXX, figure 8. Lingula cedens Barrande, 1868, Faune silurienne des environs de Hof, en Bavifere, p. 102, fig. 66. (Described in French. Fig. 66 is copied in this monograph, PL XXX, fig. 8.) Lingula cedens Barrande, 1868, Neues Jahrb. f iir Mineralogie for 1868, pp. 691-692, unnumbered plate, fig. 66. (Copy of preceding reference.) This is one of the larger shells of the fauna at Hof, but as it is deformed by pressure it is difiicult to give its specific characters. The author states that the surface of the internal cast contains traces of rather strong concentric striae, with finer intermediate striae; also traces of very fine longitudinal striae. Length, 18 mm.; greatest width, 12 mm. Barrande [1868a, p. 102] compares this form with Lingulella davisi (McCoy), from which it appears to be very little different. It is probable that an extended series of specimens would unite it with Lingulella unrthi (Barrande). Formation and locality. — Passage beds between the Upper Cambrian and the Ordovician: (303c [Barraride, 186Sa, p. 102]) Suburbs of Hof ; and (303f [Pompeckj, 1896a, pp. 7 and 8]) railway cut near Schellenberg, a little dis- tance back of the railway station at Neuhof, aiear Hof; both in Bavaria, Germany. Lingulella clarkei n. sp. Text figures 42A-D, page 486. The ventral valve of this species has the same general outline and form as that of Lingulella acutangula (Roemer) (PI. XVII, figs. 1,1a, Ig) except that it is a little broader across the front. The dorsal valve differs materially in being proportionally narrower on the posterior half and in having a broad shallow sinus extending from the umbo to the front margin. A similar sinus occurs on one dorsal valve of Lingulella manticula (Wliite) (PL XX, fig. 1 a) and on all dorsal valves of Obolus (Fordinia) perfectus Walcott (PI. LXIII, fig. 10b). The largest ventral valve has a length of 9 mm. ; width, 7 mm. A broad dorsal valve has a length of .5 mm.; width, 4.2.5 mm. 486 CAMBRIAN BEACIIIOPODA. The exterior surface is marked by very fine concentric striae or fine ridges of growtli; numerous radiating striaj occur on the ianer layers of the shell. Nothing is known of the interior of either valve. The specific name is given in honor of Prof. J. M. Clarke, of Albany, New York. Figure i2.—Lingulella clarkei n. sp. A, A', Exterior and side outline of ventral valve (U. S. Nat. Mus. Cat. No. 51853a). B, Exterior of ventral valve, the type specimen (U. S. Nat. Mus. Cat. No. 61853b). C, Broad form of dorsal valve (U. S. Nat. Mus. Cat. No. 51853c). D, Dorsal valve with exterior layer of shell exfoliated (U. S. Nat. Mus. Cat. No. 52458a). The specimens represented byflgures42A, 42B,and 42C are from Locality 68; that represented by figure42D is from Locality 60; both in Nevada. Formation and locality. — Middle Cambrian : (60) Limestone in the upper beds of the Secret Canyon shale, across the canyon from the dump of the old Richmond mine shaft; and (58) shaly limestones in the upper part of the Secret Canyon shale, east side of New York and Secret canyons; both in the Eureka district [Hague, 1892, Atlas], Eureka County, Nevada. LiNGULELLA coLLiciA (Matthew). Plate XXXV, figures 1, la-f, 2, 2a-d. ! Leptobolus ? collida Matthew, 1899, Bull. Nat. Hist. Soc. New Brunswick, vol. 4, pt. 3, No. 18, p. 200, PI. I, figs. 3a-e. (Described as a new species. Figs. 1, la-b, PI. XXXV, of this monograph are drawn from three of Matthew's specimens, but closer identification is impossible.) Obolus (Hngulella) collida (Matthew), Walcott, 1902, Proc. U. S. Nat. Mus., vol. 25, p. 610. (Characterized.) Leptobolm collida Matthew, 1903, Geol. Survey Canada, Kept. Cambrian Rocks Cape Breton, pp. 112-113, PI. VI, figs. 3a-e. (Described and discussed. Figures copied from Matthew, 1899b, PL I, figs. 3a-e.) Leptobolus collida collis Matthew, 1903, idem, pp. 114^115. (Characterized as a new variety.) This shell is associated with Lingulella atava (Matthew), but differs from that species in being larger and in having a more acuminate and broader ventral valve and more broadly oval dorsal valve. The exterior surface is marked by very fine, slightly irregular, concentric strise. The variety collis is simply a wide form, that is so closely united to L. collida by many gradations among the shells before me that I do not think it worthy of a distinct name. Formation and locality. — Middle Cambrian: (lOp) Sandstones just below the waterfall in Division E2b; (13d') sandstones opposite the third waterfall in Dugald Brook, between Divisions E2a and E2b; (344a [Matthew, 1903, p. 26]) sandy shales of Division E3c; (13n')o sandstones of Division E3e; (344d [Matthew, 1903, p. 82]) sandy shales of Division E3f; all in Matthew's [1903, p. 21] Etcheminian, Dugald Brook, Indian River, Cape Breton, Nova Scotia. (13m) Sandstones of Division ESf in Matthew's Etcheminian, Gillis Brook, eastern Cape Breton, Nova Scotia. (344e [Matthew, 1903, p. 78]) Shales of Division Eld of Matthew's Etcheminian, on Boundary Brook, eastern side of the Escasonie Indian Reservation, eastern Cape Breton, Nova Scotia, Canada. Lingulella concinna Matthew. Plate XXXIII, figures 2, 2a-h; Plate XXXIV, figures 1, la-r. Lingulella condnna Matthew, 1901, Bull. Nat. Hist. Soc. New Brunswick, vol. 4, pt. 4, No. 19, pp. 273-274, Pl.V, figs. 2a-b. (Described and discussed as a new species. PL XXXIII, fig. 2d, of this monograph is drawn from one of Matthew's specimens, but which one can not be determined.) Obolus (Lingulella) bellus Walcott (in part), 1901, Proc. U. S. Nat. Mus., vol. 23, p. 685. (Matthew's Lingulella condnna is referred to, and described with Lingulella bella.) Obolus (Lingulella) condnnus (Matthew), Walcott, 1902, idem, vol. 25, pp. 608-609. (Described and discussed some- what as on p . 487 . ) a I3n' is the type locality, though the specimens in the XTnited States National Museum collections to which that number is assigned were collected later than the type specimens. OBOLID^. 487 Lmgulella condnna Matthew, 1903, Geol. Survey Canada, Bept. Cambrian Rocks Cape Breton, pp. 203-204, PL XIV, figs. 5a-b. (Description and figures copied from Matthew, 1901a, p. 273, PI. V, figs. 2a-b.) General form ovate. Ventral valve obtusely acuminate; dorsal valve broad, rounded ovate; valves moderately convex. Surface of shell marked with numerous concentric Unes of growth and with intervening bands of strife that are somewhat undulating. Wlien the outer surface of the shell is exfoUated the shiny inner layers of the shell are marked by both con- centric and radiating striae. The shell is thin and formed of a tliin outer layer, and several thin inner layers or lamellae. In some of the layers of argillaceous shale the shell has a bluish tinge with a glistening surface, often wrinkled and ridged by longitudinal compression and also compressed into transverse ridges when the shell has been distorted by movement in the shale. In some of the specimens in the sandy layers, a few concentric lines of minute punctse occur on the posterior portion of the inner surface. A large ventral valve has a length of 15 mm. with a width of 10 mm., and a dorsal valve 11 mm. in length has a width of 8 mm. The average length of several hundred specimens of the ventral valve is from 6 to 7 mm. The cast of the area of the pedicle valve shows it to be rather long and well extended out on the cardinal slopes. A clearly defined pedicle furrow divides it midway, and a narrow flexure line occurs about halfway between the pedicle furrow and the outer margin. The area is marked by fine strise of growth parallel to the margin. The area of the brachial valve is short and seldom well preserved. The cast of the interior of the valves, both in the argillaceous and sandy shale, shows almost no traces of vascular markings or muscle scars. Observations. — When studying this species in 1901 I had a few specimens which at the time I considered to be identical with Lingulella hella (Walcott). During the season of 1901 S. Ward Loper collected many hundred specimens on McNeil Brook, and other localities in Cape Breton, that clearly showed that Matthew [1901a, p. 273] was correct in assigning it to a distinct species. I was not sure that his Lingulella lens (Matthew) was distinct, as the material from which he described and figured it was badly crushed and broken, the fragments of shell being embedded together in the limestone. None of the t3'pical specimens show the apex of the ventral valve. The one used in illustration by Matthew [1901a, PI. V, fig. 3a] has aU the apex broken away, and the shell is somewhat compressed laterally. A photograph of this specimen of Lingulella lens (Matthew) is reproduced in Plate XXXIII, figure 1 . Among the collections made by Loper, there are a large number of shells crushed and crowded together very much as in the typical material of Lingulella lens used by Matthew. There are, however, in the accompanying shales large numbers of individual specimens which are beautifully preserved, which illustrate the outline and con.vexity of the shell. The series Ulustrates the growth of the shell, also the various forms in which it occurs owing to the differ- ence in sediment in which it has been embedded. The material collected by Loper came from several horizons of the Upper Cambrian. Matthew [1901a, pp. 273-274] assigns "Lingulelh, condnna" to the Dictyonema zone, and "Lingula lens" to the Parabolina zone. The shells in the arenaceous shales on McAdam shore are clearly Lingulella condnna, but in the calcareous layers the shells are different and I retain the name lens for them. I received from Dr. G. Lindstrom a specimen from the black Dictyonema shales of Skane, Sweden, labeled "Lingulella natTiorsti Linnarsson." This is evidently an accident, as that species occurs only in the Lower Cambrian and the specimen is a broader shell much like that of L. condnna of Cape Breton. With our present information it is provisionally referred to L. condnna. Formation and locality. — Upper Cambrian: (3h) Shale and shaly limestone on McNeil Brook, 1.5 miles (2.4 km.) east of Marion Bridge; (307 [Matthew, 1903, p. 204]) shales of Division CScof Matthew on McLeodBrooh {==Barachois i?iDer)/(10c) shales on west side of Barachois River; (lOn) shale in ravine on east side of Barachois Glen, 3 miles (4.S km.) from Barachois; (lOe, lOf, lOg, and lOh) shale on small east branch of Barachois River, about 0.75 mile (1.2 km.) north of the crossroad fromBoisdale to Upper Leitches Creek; (8d and 373) shale at Upper Leitches Creek; (10m and 372a) shale 2 miles (3.2 km.) south of the Boisdale Road from Upper Leitches Creek; (lOd and lOi) shale in high bank on west side of Barachois River, just north of the Boisdale Road; (131i) shale on east bank of Barachois River, 1.5 miles 488 CAJMBKIAN BEACHIOPODA. (2.4 km.) north of Boisdale; (101) shale on east bank of Barachois River, 6 miles (9.6 km.) from Little Bras d'Or Lake; (3q) shale in Barachois Glen, 4 miles (6.4 km.) south of Little Bras d'Or Lake; (3p and 372h) shale in ravine 0.5 mile (0.8 km.) north of McMullins, on the crossroad to Boisdale; (16o) shales on McMullins Brook, in the east Boisdale district; (3o and 372c) shale in ravine east of the railroad, just south of Barachois; and (372d) shale on McAdam shore on East Bay, east of Bras d'Or Lake; all in eastern Cape Breton, Nova Scotia. Middle Cambrian: (3i) Compact, fine-grained, thin-bedded, gray sandstone of the Paradoxides zone, on McLean Brook, 1 mile (1.6 km.) east of McCodrum Brook and 1.5 miles (2.4 km.) west of Marion Bridge, eastern Cape Breton, Nova Scotia. A specimen from the following locality is provisionally referred to Lingulella condnna: TTpper? Cambrian: (310h) Shale collected somewhere (probably Fogelsang), in the old Province of Skane, now the Provinces of Malmohus and Christianstad, Sweden. Lingulella cuneola (Whitfield). Plate XXVII, figures 7, 7a-b. Lingulepis cuneolus Whitfield, 1877, U. S. Geog. and Geol. Sui-vey Rocky Mtn. Region, Rept. Geology Black Hills of Dakota; Prelim. Rept., pp. 8-9. (Described and discussed as below as a new species.) Lingulepis cwneoZus Whitfield, 1880, U. S. Geog. and Geol. Survey Rocky Mtn. Region, Rept. Geology and Resources Black Hills of Dakota, by Newton and Jenney, p. 336, PI. II, figs^ 5 and 6. (Description copied from preceding reference. The specimen represented by fig. 6 is redrawn in this monograph, PL XXVII, fig. 7.) Obolus (Lingulella) cuneolus (WhitQeld) , Walcott, 1899, Mon. U. S. Geol. Survey, vol. 32, pt. 2, p. 443. (Merely changes generic reference.) The original description by Whitfield follows : Shells small, rather below the medium size, triangularly ovate in outline or sometimes subctmeatej ventral valve triangularly ovate, with a sharp somewhat pointed beak, the width and length about as three and four, and the point of greatest width near the lower thu-d of the length of the valve; cardinal slopes abrupt, scarcely convex; basal line rounded at the sides, but nearly straight in the middle; surface of the valve strongly convex, becoming almost sub- angular in the upper part; dorsal valve much shorter proportionately than the ventral, the length but little exceeding the width; side and base more rounded and the beak truncate; surface distinctly convex. Surface of the shell apparently smooth, but usually exfoliated, in which condition a few fine radiating lines are visible. This shell differs from L. ■pinnaformis Owen in size and in the more distinctly cuneate form of the ventral valve. At first sight it might be taken for the young of that species, but a little critical examination soon reveals marked dis- tinctions in the truncation of the front margin, and especially in the form of the cardinal slopes, which are rounded and never concavs, as in almost all ventral valves of that species. In consequence of this latter feature the beak does not appear so attenuated as in that one, although proportionately quite as long. In the general surface characters and form of the valves it corresponds with the genus Lingulepis, although we have not been able to distinguish the muscular impressions. Were it not for the diffei'ence in the size of the shells we should be inclined to think this might be the species figured by Messrs. Meek and Hayden [1865, p. 3, PL I, figs, la-b] as Lingulepis dakoiensis; but as their figures appear to be of the natural size, we should suppose it to be very distinct, as all the specimens of our shell noticed have been small, none exceeding one-fourtb of an inch in length. Observations. — This species does not appear to be correctly referred to Lingulepis. In outline it resembles some of the cuneate forms of Lingulella, and in its thick laminated shell it upprosbches Lingulella phaon (Walcott) (PI. XXVI). Like that species, it has a thick outer layer and strong, radially striated inner layers, and numerous lamellae slightly oblique to the outer layer over the anterior portions of the shell, especially about the anterior and lateral margins. Most of the specimens are in the form of partial casts, only a portion of the outer shell adhering to the cast. The form of the ventral valve approaches that of some of the broader shells of Lingulella perattenuata (Whitfield) (PI. XXI). It differs, however, in being more cuneate. Except for the somewhat straighter slope of the sides toward the beak it might be identified with Lingulella acutangula (Roemer) (PI. XVII). Although fairly large collections were made from the Cam- brian formations in the Black Hills during the field season of 1897, no specimens were found that could be definitely identified as belonging to this species, the only material available for study being that in the original collections of W. P. Jenney. Formation and LOCALrry. — Middle Cambrian: (355) Sandstones in Red Canyon Creek, southwest sidfe of the Black Hills, South Dakota. OBOLID^. 489 Specimens somewhat doubtfully referred to this species occur at the following locahty : Middle Cambrian : (167) Sandstone beneath limestone and resting on the pre-Cambrian in a bluff 9 miles (14.4 km.) west of Custer, Black Hills, South Dakota. LiNGIILELLA DAMESI (Walcott)." Plate XXXIX, figures 8, 8a-c. Obolus (Lingulella) damesi Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 329. (Characterized as below as a new species.) The general descriptions of Obolus chinensis (Walcott) (p. 387) and Lingulella j^rima (Hall) (p. 526) apply so closely to this species that it does not appear necessary to do more than call attention to the points in which they differ. From Obolus chinensis (PL XXXIX) this species varies in having a more elongate, acuminate ventral valve and a more ovate dorsal valve ; the valves are also less convex. From Lingulella prima (PI. XXVII) it differs in the more gradual curvature of the sides from the apex to the front margin, in this respect resembhng some varieties of L. ferruginea Salter (PI. XXIX). The average size of the ventral valve is about 5 mm. in length by 3.5 mm. in width. The specific name was given in honor of Dr. W. Dames. Formation and locality. — Middle Cambrian: (C7) Lower limestone member of the Kiulung group [Black- welder, 1907, pp. 37 and 39 (last list of fossils), and fig. 8a (bed 33), p. 29], 2.2 miles (3.5 km.) southwest of Yenchuang; and (CIO) lower shale member of the Kiulung grouj) [Blackwelder, 1907, pp. 37 and 40 (part of 3d list of fossils), and fig. 8a (bed 35), p. 29], about 3 miles {4.8 km.) southwest of Yenchuang; both in the Siatai district. Shantung, China. A shell which may be a variety of this species occurs at the following locahty: Upper Cambrian: (C64) Upper limestone member of the Kiulung group [Blackwelder, 1907, pp. 37 and 42 (first list of fossils), and fig. 10 (bed 20), p. 38], 2.7 miles (4.3 km.) southwest of Yenchuang, Sintai district, Shantung, China. Lingulella davidsoni (Barrande). Plate XXXII, figures 1, la-e. Lingula davidsoni Barrande, 1879, Systeme silurien du centre de la Bohems, vol. 5, PL CIV, figs, vm: 1—4. (Not described, but figm-ed as a new species. PL CIV, figs, vin: lA, lb, 3A, 3b, 4E, and 4 are reproduced in this monograph, PL XXXII, figs. 1, la-e, respectively.) In the absence of specimens for study an opinion of the generic relations of this fine species is necessarily based on the illustrations given by Barrande. Comparing Plate XXXII, figures 1 and lb, with Plate XVII, figure la, we note at once the similarity between Lingulella davidsoni and L. acutangula (Roemer) in their general form and the character of their areas as far as shown for Lingulella davidsoni. Fragments of the exterior shell of the latter (PI. XXXII, fig. lb) may be compared with the exterior surface of the former (PI. XVII, fig. 1). The dark oval spots in front of the area in figure Id may be of importance, or they maj'^ represent only a depres- sion on each side of the median ridge such as often occurs in compressed shells. If this species is a typical Lingulella, it is one of the last of its race, occurring as it does in Etage d4 of Barrande's section. The specific name was given in honor of Thos. Davidson. Formation and locality. — Ordovician: (303m) Etage d4 at Lieben; (303n) Etage d4 at Wraz; and (303o) Etage d4 at Lodenitz; all [Barrande, 1879b, PL CIV] in Bohemia, Austria-Hungary. Lingulella davisi (McCoy). Plate XXX, figures 2, 2a; Plate XXXI, figures 6, 6a-h. Lingula sp. Davis, 1846, Quart. Jour. Geol. Soc. London, vol. 2, pt. 1, p. 70. (Mentioned only.) Not Lingula ovata McCoy, 1846, Silurian Fossils of Ireland, p. 24, PL III, fig. 1. (Described and discussed. This species is not taken up in this monograph.) a Better preserved and more complete series ol specimens of this species collected by Ur. J. P. Iddings, in Manchuria, indicate that the form bears a closer relationship to Obolus than to Lingulella. In the volume on Paleontology of Willis's work on Research in China (Carnegie Insti- tution of Washington) the species will be described and figured under the title, Obolus damesi (Walcott). 490 CM'IBRIAN BRACHIOPODA. Lingula sp. Sedgwick, 1847, Quart. Jour. Geol. Soc. London, vol. 3, pt. 1, pp. 140, 143, and 147. (Mentioned only.) Tellinomya lingulx-comes McCoy [not Salter], 1851, Annals and Mag. Nat. Hist., 2d ser., vol. 7, p. 56. (Described and discussed. Salter's species is not a brachiopod and is not taken up in this monograph.) lAngida davisi McCoy, 1851, idem, vol. 8, pp. 405^06. (Described and discussed as a new species.) Lingula davisi McCoy, 1854, British Paleozoic Fossils, p. 252, PI. IL, figs. 7, 7a-b. (Description copied from preceding reference and one locality added,) Lingula ovata McCoy (in part), 1854, idem, p. 254, PL IL, figs. 6 and 6a. (Described and discussed. Specimens of Lingulella davisi were included with "Lingula ovata" in this description. The specimens belonging with Lingula ovata are not taken up in this monograph.) Tellinomya linguliromes McCoy [not Salter], 1854, idem, p. 274, PL IX, fig. 18. (Described and discussed almost aa in McCoy, 1851h, p. 56.) Lingulella davisi (McCoy), Salter, 1866, Mem. Geol. Survey Great Britain, vol. 3, pp. 333-334, PL II, figs. 7-12, PL IV, figs. 14 and 14a. (Described in Latin and discussed in English.) Lingulella davidi (McCoy), Davidson, 1866, British Fossil Brachiopoda, vol. 3, pt. 7, No. 1, pp. 56 and 57, PL IV, figs.' 1-16. (Described and discussed. Figs 9, 3, 7, 6, 4, 5, 13, 14, and 15 are copied from Salter, 1866b, PL II, figs. 7-12, and PL IV, figs. 14 and 14a, respectively. Figs. 10, 11, and 12 are reproduced in this monograph, PL XXXI, figs. 6, 6a-b, respectively.) Lingulella davisii (McCoy), Salter, 1867, Siluria, by Murchison, 4th ed., pp. 44 (and footnote) and 52; fossils (5) fig. 1; fossils (10), fig. 11. (Mentioned.) Lingulella davisi (McCoy), Davidson, 1868, Geol. Mag., vol. 5, pp. 304 and 306, PL XV, figs. 13-15. (Species discussed.) Lingulella davisi (McCoy), Meek, 1871, Proc. Acad. Nat. Sci. Philadelphia for 1871, vol. 23, pp. 186-187, fig. 2, p. 185. (Discussed in discussion of "Lingulella lamborni." Fig. 2 is copied from Davidson, 1866, PL IV, fig. 14.) Lingulella davvdi (McCoy), Hall, 1873, Twenty-third Ann. Eept. New York State Cab. Nat. Hist., PL XIII, fig. 4. (No text reference. Fig. 4 is copied from Davidson, 1866, PL IV, fig. 16.) Lingulella davidi (McCoy), Roemer, 1876, Lethsea geognostica, pt. 1, Letheea palseozoica, Atlas, PL II, figs. 5a-c. (No text reference.) Lingulella davisii (McCoy), Salter and Etheridge, 1881, Mem. Geol. Survey Great Britain, vol. 3, 2d ed., pp. 537-538, PL II, figs. 7-12; PL IV, figs. 14 and 14a. (Copied from Salter, 1866b, p. 333, PL II, figs. 7-12; PL IV, figs. 14 and 14a.) Lingulella sp. Kayser, 1883, China, by Richthofen, vol. 4, pp. 35-36, PL III, fig. 3. (Described in German. Fig. 3 is reproduced in this monograph, PL XXX, fig. 2a.) Lingulella davisi (McCoy), Hall and Clarke, 1892, Eleventh Ann. Rept. State Geologist New York for 1891, p. 232, fig. 239. (No text reference, figure copied from Salter, 1866b, PL IV, fig. 14a.) Lingulella david (McCoy), Hall and Clarke, 1892, Forty-fifth Ann. Rept. New York State Museum for 1891, p. 548, fig. 239. (Copy of preceding reference.) Lingulella davisi (McCoy), Hall and Clarke, 1892, Nat. Hist. New York Paleontology, vol. 8, pt. 1, pp. 56 and 57, fig. 18. (Discussed in the text and figure copied from Salter, 1866b, PL IV, fig. 14a.) Lingulella cf. davini (McCoy), Kayser, 1897, Zeitschr. Deutsch. geol. Gesell. for 1897, Bd. 49, Heft 2, No. 2, p. 280, PL VII, fig. 6. (Characterized. Fig. 6 is reproduced in this monograph, PL XXX, fig. 2.) Obolus (Lingulella) davidi (McCoy), Walcott, 1898, Proc. U. S. Nat. Mus., vol. 21, pp. 394 and 395, PL XXVII, figs. 1-5. (Mentioned in discussion of genus Lingulella. The specimens represented by figs. 1, 2, 4, and 5 are redrawn in this monograph, PL XXX, figs. 6f, 6d, 6e, and 6h, respectively.) Lingulella ct. davidi (McCoy), Matthew, 1902, Bull. Nat. Hist. Soc. New Brunswick, vol. 4, pt. 5, No. 20, pp. 407-^08. (Described.) Lingulella cf. davisii (McCoy), Matthew, 1903, Geol. Survey Canada, Rept. Cambrian Rocks Cape Breton, p. 203. (Copied from preceding reference.) The characters of this species, as far as known to me, are illustrated on Plate XXXI, and reference is made to some of them in the description of the genus Lingulella. Many interest- ing observations are given by Davidson [1866, p. 57] in his description of the species and its occurrence at various localities in Wales. E. Kayser [1897, PI. VII, fig. 6] illustrates a dorsal ? valve from the Cambrian beds of Iruya, Province of Salta, Argentina, which he compares with Lingulella davisi. The specimen indicates the presence of a form that may be the representative of L. davisi, but it may be a new form, or possibly identical with some one of the species of the Atlantic basin fauna found in New Brunswick or Newfoundland. The original figure is reproduced on Plate XXX, figure 2. The form illustrated by Kayser [1883, PI. Ill, fig. 3] in the report on the Cambrian brachi- opods of Liaotung is also suggestive of Lingulella davisi, as may be seen by comparing a copy of Kayser' s figure on Plate XXX with the illustration of L. davisi on Plate XXXI, figure 2a. OBOLIDyE. 491 It should also be compared with Lingulella ampla (Owen) (PI. XXVIII, figs. 1, la-j) of the Mississippi Valley. The specific name was given in honor of Mr. J. E. Davis, who first called attention to the species. Formation and locality." — Ordovician : (304n) "Coiiiston(Bala) limestone" [McCoy, 1854, p. 254], at Coniston, Lancashire, England. trpper Cambrian : (366d) Lower Lingula flags at Camedd Filiast, Bangor; (366e) Lower Lingula flags at Marchillyn- mawr, Llanberis; both [Davidson, 1866, p. 57] in Carnarvonshire, North Wales. Lower Lingula flags at the following localities : (366f) Ffestiniog; (366g) Dolgelly ; (366h) Pen-y-Bryn, 5 miles (S km.) north of Dolgelly; (366i) Llyn Dywarchen; (366]) Pont Nan t-y-Lladron, on the Bala Road; (366k)6 Penmorfa; (3661)6 Tremadoc; and (366m)6 near Nant-y-Groes, west of Bala; all [Davidson, 1866, p. 57] in Merionethshire, North Wales. (366n) Lower Lingula flags at Portmadoc; (366o) "Bala schists" [McCoy, 1854, p. 254] at Bryn Melyn, near Bala; (366p [Davidson, 1866, p., 57]) Upper Tremadoc beds at Deudraeth; (366q [Davidson, 1866, p. 57]) Upper Tremadoc beds at Garth, opposite Portmadoc; and (366a) upper portion of Middle Lingula flags, 6 miles (9.6 km.) east of Ffestiniog; all in Merionethshire, North Wales. (366r) Shale 2 miles (3.2 km.) north of Builth, Brecknockshire; and (366 [Davidson, 1866, p. 57]) atWhitesand Bay, near St. Davids Head, Pembrokeshire; both in South Wales. (318m [Davidson, 1866, p. 57]) Near the base of the lower black slates, in the Waterfall Valley near Maentwrog, North Wales. (307a [Matthew, 1903, p. 203]) Shales of Division C3c2 of Matthew on McLeod Brook (=Barachois River), near Bois- dale, eastern Cape Breton, Nova Scotia, Canada. (389d [Kayser, 1897, p. 280]) Iruya, Province of Salta, Argentina, South America. (332 [Kayser, 1883, p. 35]) Limestones at Saimaki, Liaotung, China. LiNGTJLELLA DELGADOI n. Sp. Plate XXIX, figures 6, 6a-o. Lingulepis acuminata meehi Delgado [not Wai.cott], 1904, Communicagoes Commissao Servigo Geol. Portugal, tome 5, fasc. 2, pp. 366-367, PI. IV, figs. 17 and 27; PL VI, fig. 9. (Characterized and discussed in French. A photo- graph of the specimen represented by fig. 27 (reverse view) is reproduced in this monograph, PI. XXIX, fig. 6b.) Lingulella granvillensis Delgado [not Walcott], 1904, idem, pp. 367-368, PI. IV, figs. 15, 16, 18, and 19. (Discussed in French. Photographs of the specimens represented by figs. 16 and 18 are reproduced in this monograph, PI. XXIX, figs. 6 and 6a, respectively.) Lingulella ferruginea Delgado [not Saltee], 1904, idem, pp. 368-369, PI. IV, figs. 20 and 21; PI. VI, fig. 2. (Discussed in French.) Lingulella cf. linguloides Matthew, Delgado, 1904, idem, pp. 369-370, PL IV, fig. 14. (Described and discussed in French. A photograph of the specimen represented by fig. 14 (reverse view) is reproduced in this monograph, PI. XXIX, fig. 6c.) This is one of the abundant and variable forms in the fauna of the Province of Alemtejo. It may be compared in this respect with the widely distributed Lingulella ferruginea Salter. Delgado compares different phases of it to three species, two of which, L. ferruginea Salter and L. cf. linguloides Matthew, I think are specifically the same. Lingulella granvillensis Walcott has the same flattening along the median line of the ventral valve. As stated by Delgado [1904, p. 367], there is a strong resemblance between the representatives of the two forms, but I think that it is better to give the Portuguese form a distinct specific name than to identify it with the American species. Delgado sent me enlarged photographs of the specimens of the three varieties which he recognized and illustrated, and I have reproduced four of them, Plate XXIX, figures 6, 6a-c. It is quite probable that if I had all of Delgado's specimens to study a different disposition would be made of the specific references, but with present knowledge and experience of the variability of species like this, especially where the shells have been more or less misshaped by lateral movement in the "schists," I prefer to combine the forms in one species. The specific name is given in honor of the late Dr. J. F. Nery Delgado. • Formation and locality. — Lower Cambrian: (351 [Delgado, 1904, pp. 366-369]) Shales at Monte de Valbom, northeast of Villa Boim, Province of Alemtejo, Portugal. a The species also occurs in Locality 317b (p. 248). i> Davidson does not state which of the three localities (366k, 366 1, or 366m) is the type. 492 CMiBRIAN BRACHIOPODA. LiNGXILELLA DESIDERATA (Walcott). Plate XX, figures 4, 4a-c, 5, 5a-j. Obolus {Lingulella) desideratus Walcott, 1898, Proc. U. S. Nat. Mus., vol. 21, pp. 399-400. (Described and discussed as a new species.) Obolus {Lingulella) desideratus Walcott (in part), 1899, Mon. U. S. Geol. Survey, vol. 32, pt. 2, pp. 445^46, PL LX, fig. 2 (not 2a). (Described essentially as below, and discussed. The specimen represented by flg. 2 is redrawn in this monograph, PI. XX, flg. 4. The specimen represented by fig. 2a is referred in this monograph to Obolus rotundatus, PL XX, fig. 2e.) Dicellomus nanus Walcott (in part) [not Meek and Hayden], 1899, idem, p. 447, PL LX, fig, 3 (not figs. 3a-d). (Mentioned. The specimen represented by fig. 3 is redrawn in this monograph, PL XX, fig. 5j. The speci- mens represented by figs. 3a-d are referred in this monograph to Dicellomus nanus.) Shell small, subovate, with the ventral valve obtusely acuminate, and the dorsal valve broadly ovate. Valves are strongly convex, with the ventral valve fully as much so as the dorsal. There is a slight variation in the outline of the valves, some being slightly more rounded posteriorly than others. The surface of the shell is marked by fine, concentric lines of growth, and between them very fine, slightly irregular stride; a few rather narrow indistinct undulations radiate from the umbo toward the front and lateral margins; when the outer shell is partly exfoliated the outer surface of the inner layer is marked by very fine indistinct radiating striiB; there are a few traces of small, scattered pits or punctse on the inner surface. The shell is thin and formed of an outer layer and one or more inner layers or lamellae. The average length of the ventral valve is about 4 mm.; width, 3 mm. A dorsal valve 3.5 mm. long has a width of 3 mm. A cast of the interior of a ventral valve shows an area of medium length, divided midway by a narrow, clearly defined pedicle groove. The area of the dorsal valve is short. Nothing is known of the interior of the ventral valve, but in a cast of a dorsal valve there are traces of the main vascular sinuses, central median septum, and the central muscle scars. Ohservations. — This species may be compared with the Middle Cambrian Lingulella ferru- ginea Salter of the Atlantic basin faunas, and L. similis (Walcott), of the Black Hills, upper JCssissippi Valley, and Appalachian faunas. Lingulella similis is more convex and narrower, and L. manticula (White) is considerably more acuminate. Compared with the Rocky Moun- tam species it is intermediate between L. manticula and L. rotunda (Matthew). It may also be compared with L. granvillensis Walcott of the Olenellus fauna of eastern New York, and L. idle (Billings) of the Lower Ordovician fauna of Newfoundland. It is distinguished from L. granvillensis by its more regularly rounded anterior margin. The specimens represented by Plate XX, figures 4b, 4c, and 5j, are broader proportionately than the typical specimens represented by Plate XX, figures 4 and 4a, but they occur at the same geological horizon in the Eureka district, Nevada. What appears to be the same, or a closely related species, occurs in the upper beds of the Secret Canyon shale in the Eureka dis- trict, Nevada. A form that appears to be identical occurs in considerable abundance in Alabama and Tennessee. The similarity in form between the specimens from Wyoming and Nevada, and those from Alabama and Tennessee is shown by Plate XX, figures 4, 4a-c, of the typical specimens, and Plate XX, figures 5, 5a-i, of their representatives in the Appalachian region. This similarity is even more striking when the specimens are compared directly with one another, and some allowance made for the fact that the Appalachian specimens have all been more or less compressed. A small shell that appears to be identical with this species occurs in the red sandstone and argillaceous shale of the Lower Ordovician of Colorado. The specimens from Trout Creek, below Bergen Park, are much like those from the Gallatin Range in Montana and the same species of Billingsella is associated with them. At Cement Creek, 10 miles (16.1 km.) south- east of Crested Butte, Colorado, the shells occur in a fine conglomerate and coarse sandstone OBOLIDiE. 493 associated with a species of Bathyurus much like that from the beds containing Lingulella desiderata at Trout Creek. Formation and locality. — Lower Ordovician: (360) Red siliceous limestone near Colorado Springs; (186) near line of contact between red and gray Ordovician limestones, in red siliceous limestone about 30 feet (9.1 m.) above the pre-Cambrian rocks, Williams Canyon, Manitou; (187) red siliceous limestone 105 to 122 feet (32 to 36.7 m.) above the pre-Cambrian rocks, 2 miles (3.2 km.) below Manitou Park Hotel; (360a) red siliceous limestone on west side of Trout Creek, below Bergen Park, 7 miles (11.2 km.) north-northwest of Manitou; all in El Paso County, Colorado. (360b) Red siliceous limestone on Cement Creek, 3 miles (4.8 km.) north of Hot Springs, Ouray County; and (360c) red siliceous limestone about 10 miles (16.1 km.) southeast of Crested Butte, Elk Range; both in Colorado. Upper Cambrian: (161) Limestone on the south side of West Gallatin (Gallatin) River, northwest of Hamilton, on the north side of the Gallatin Valley, Gallatin County, Montana. (7x, 7y, and 7z) Limestone of the Emigrant formation [Tmner, 1902, p. 265], about 2.5 miles (4 km.) southeast of the summit of Emigrant Pass, Silver Peak quadrangle (U. S. Geol. Survey), Esmeralda County; (8n) limestone about 500 feet (152 m.) up in the limestones east of Swallow Ranch, west side of Snake Range, 20 miles (32.2 km.) south of Osceola, White Pine County; (313) limestone 0.75 mile (1.2 km.) east-northeast of McGill post office, \%ite Pine County; and (61) limestone in the Dunderberg shale [Walcott, 1908f, p. 184], a little south of the Hamburg mine. Eureka district [Hague, 1892, Atlas], Eureka County; all in Nevada. (30h) About 350 feet (106.7 m.) above the Middle Cambrian and 2,950 feet (899.2 m.) below the top of the Upper Cambrian near the base of the arenaceous limestones forming 2a of the Orr formation [Walcott, 1908f, p. 177]; and (30j and 30k) 950 and 1,150 feet (289.6 and 350.5 m.) above the Middle Cambrian and 2,450 and 2,175 feet (746.8 and 662.9 m.) below the top of the Upper Cambrian, in the arenaceous shales and limestone forming le of the Orr forma- tion [Walcott, 1908f, p. 176]; all on Orr Ridge, about 5 miles (8 km.) south of Marjum Pass, House Range [Walcott, 1908f, PI. XIII], Millard County, Utah. (ISd)" Thin-bedded blue limestone near Cave Spring on the east side of the Fish Spring Range, about 4 miles (6.4 km.) south of the J. J. Thomas ranch, Juab County; (34t) limestone 1.5 miles (2.4 km.) northwest of Wahwah Springs, about 80 feet (24.4 m.) below the highest point on the north side of the road at Cane Pass, Wahwah Moun- tains, Beaver County; (32g) about 2,575 feet (784.9 m.) above the Cambrian quartzitic sandstones in a blue limestone about 2 miles (3.2 km.) southeast of Muskrat Springs on the northwest face of Grantsville Peak, Stansbury Range, Tooele County; (54j) about 700 feet (213.4 m.) above the Middle Cambrian and 525 feet (160 m.) below the top of the Upper Cambrian in the arenaceous limestones forming 2c of the St. Charles formation [Walcott, 1908f, p. 192], in Blacksmith Fork Canyon, about 10 miles (16.1 km.) east of Hyrum, Cache County; all in Utah. (5a and 54t) Limestones of the St. Charles formation [Walcott, 1908a, p. 6] about 250 feet (76 m.) above the Middle Cambrian on the north side of Twomile Canyon, near its mouth, 2 miles (3.2 km.) southeast of Malade, Oneida County, Idaho. (93 and 93o) Shales and limestones at the base of the Knox dolomite near Jordan's, just below the ford on Cowan Creek, about 8 miles (12.8 km.) southeast of Center; (93a) b same horizon as Locality 93 on Terrapin Creek road from Center to Amberson; (94o) same horizon as Locality 93, 0.25 mile (0.4 km.) beyond Givens Ford, on Cowan Creek, about 8 miles(12.8 km.) southeast of Center; and (94xx) same horizon as Locality 93 at Givens mill, on Cowan Creek, about 8 miles (12.8 km.) southeast of Center; all in Cherokee County, Alabama. (361) Shaly limestone in suburb of Attalla, Etowah County, Alabama. (96) Limestones near the ford on the Cedartown road, 1.5 miles (2.4 km.) south of Rome, Floyd County; and (362) shales in the Oothkalooga Valley, Bartow County; both in Georgia. (107u and 107o) Limestones and shales at the base of the Knox dolomite, west of the top of Copper Ridge, near the Southern Railway cut, about 10 miles (16.1 km.) northwest of Knoxville [Keith, 1896b, areal geology sheet], Knox County, Tennessee. (122a) c Shale at the headwaters of Forgey Creek, northwestern part of the Greeneville quadrangle (U. S. Geol. Survey), Hawkins County, Tennessee. Upper? Cambrian: (66) Limestone at Sierra Springs, eastern base of Lookout Mountain, Eureka district [Hague, 1892, Atlas], Eureka County, Nevada. Middle? Cambrian: (313c) Limestone about 12 miles (19.3 km.) west-southwest of Alpha Station, Eureka County, Nevada. Middle Cambrian: (57) Shaly Eldorado limestone [Walcott, 1908f, p. 184] at the 700-foot (213.4 m.) level of the Richmond mine. Ruby Hill [Hague, 1892, p. 43, and PL I, opposite p. 116]; (57b) limestones at the north end of Mineral Hill, just south of Ruby Hill [Hague, 1892, p. 43, and PL I, opposite p. 116]; (60) limestones in upper beds of Secret Canyon shale, across the canyon from the dump of the old Richmond mine shaft; and (58) shaly limestones in upper beds of Secret Canyon shale, east side of New York and Secret canyons; all in the Eureka district [Hague, 1892, Atlas], Eureka County, Nevada. (313b) Limestone 3 miles (4.8 km.) north-northeast of Schellbourne, Schell Creek Range, 'V^Tiite Pine County, Nevada. a This species also occurs at Locality 341 (p. 196). 6 The species is somewhat doubtfully identified from this locality. c This species also occurs at Locality 122 (p. 223). 494 CMIBRIAN BRACHIOPODA. (15x) Limestones near the middle of the Fish Spring Range, near the line between Juab and Tooele counties; and (15p) limestones near the north end of the Fish Spring Range, Tooele County; both in Utah. (5b) Dark blue-gray Langston limestone [Walcott, 1908f , p. 198], just above the Cambrian quartzitic sandstones, on the north side of Twomile Canyon, near its mouth, 2 miles (3.2 km.) southeast of Malade, Oneida County; (59f) lime- stones immediately underlying the Spence shale member of the Ute limestone [Walcott, 1908a, p. 8], in a saddle north of the creek which flows into Mill Canyon from the west, about 5 miles (8 km.) west-southwest of Liberty and 15 miles (24.2 km.) west of Montpelier, Bear Lake County; and (55c and 163) Spence shale member of the Ute limestone PiV'alcott, 1908a, p. 8], about 50 feet (15.2 m.) above the Brigham quartzite and 2,755 feet (839.7 m.) below the Upper Cambrian, in a ravine running up into Danish Flat from Mill Canyon, about 6 miles (9.6 km.) west-southwest of Lib- erty and 15 miles (24.2 km.) west of Montpelier, Bear Lake County; all in Idaho. (55e) Spence shale member of the Ute limestone about 100 feet (30.5 m.) above the Brigham quartzite [Walcott, 1908f, p. 197], at the mouth of the first small canyon south of Wasatch Canyon, east of Lakeview ranch, 5 miles (8 km.) north of Brigham, Boxelder County, Utah. (311 and 541i) About 3,140 feet (957.1 m.) above the Brigham quartzite and 1,050 feet (320 m.) below the Upper Cambrian in the limestones forming la of the Bloomington formation [Walcott, 1908f, p. 194]; and (541) about 500 feet (152.4 m.) above the Brigham quartzite and 3,700 feet (1,127.8 m.) below the Upper Cambrian in the Spence shale member of the Ute limestone [Walcott, 1908f, p. 197]; both in Blacksmith Fork Canyon, about 10 miles (16.1 km.) east of HjTum, Cache County, Utah. (3021) Limestone in the Gallatin Range; and (302b) limestone near Crowfoot Ridge, Gallatin quadrangle (U. S. Geol. Survey) ; both in Yellowstone National Park, Wyoming. (5f) Limestones interbedded in the Wolsey shale [Weed, 1900, p. 285], in Meagher County on the road to Wolsey, about 4 miles (6.4 km.) south of the divide at the head of Sawmill Creek and 11 miles (17.7 km.) south of Neihart, Little Belt Mountains quadrangle (U. S. Geol. Survey), Cascade County, Montana. (581) About 1,830 feet (557.8 m.) above the Lower Cambrian in the limestone forming 3b of the Stephen formation [Walcott, 1908c, p. 238(7)], on the east side of Mount Stephen about 3,000 feet (914.4 m.) above the Canadian Pacific Railway track, 3.5 miles (5.6 km.) east of Field, British Columbia. (88a) Limestone about 100 feet (30.5 m.) above the quartzitic sandstone at the base of the Cambrian, in the north- ern suburbs of Deadwood, in the Black Hills, South Dakota. (9) Limestone on southeastern slope of ridge 1 mile (1.6 km.) north of the northwest corner of Harlans Knob, about 4 miles (6.4 km.) northeast of Rogersville [Keith, 1905, areal geology sheet]; (9a) same horizon as locality No. 9 in limestone on the south shore of Holston River at Melinda Ferry, 5 miles (8 km.) southwest of Rogersville [Keith, 1896a, areal geology sheet]; (101a and 101b) Rogersville shale near the schoolhouse, 3.5 miles (5.6 km.) southwest of Rogersville, on the road to Melinda Ferry; (103b) third limestone south of the ridge of sandstone in the Rome formation ("Town Knobs "), on the road from Rogersville to Dodson Ford, near the line between the Morristown and Greeneville quadrangles (U.S. Geol. Survey); and (121) Rogersville shale, road just east of Harlan Knob, 4 miles (6.4 km.) northeast of Rogersville [Keith, 1905, areal geology sheet]; all in Hawkins County, Tennessee. (117) Shales on the road north from Greeneville, Greene County, Tennessee. (369g) Shales at Bonneterre, St. Francois County, Missouri. (90b) Conasauga limestone, in cut on the Louisville and Nashville Railroad, near Woodstock, Bibb County; (16) Conasauga ("Coosa") limestone, Blountsville Valley, Blount County; and (139) limestone on Hokes Bluff road, north of the chert outcrop, 5 miles (8 km.) east of Gadsden, Etowah County; all in Alabama. Specimens somewliat doubtfully referred to this species occur at the following locality: Middle Cambrian: (107a) Shale in railroad cut in Bull Run, northwest of Copper Ridge [Keith, 1896b, areal geology sheet], 11 miles (17.7 km.) northwest of Knoxville, Knox County, Tennessee. LlNGtTLELLA DUBIA (Walcott). Plate XXIV, figures 4, 4a. Lingulella ella Walcott (in part) [not Hall and Whitfield], 1886, Bull. U. S. Geol. Survey No. 30, pp. 97-98, PI. VIII, figs. 4b and 4c (not PL VII, fig. 2, or PL VIII, figs. 4, 4a, 4d, and 4e). (Original description. Hall and Whitfield, 1887, p. 232, copied and species described and discussed. The specimens represented by figs. 4b and 4c are redrawn in this monograph, PI. XXIV, figs. 4 and 4a, respectively. The specimens represented by PL VII, fig. 2, and PL VIII, figs. 4, 4a, 4d, and 4e, are referred in this monograph to Obolus (Westonia) ella.) Lingulella ella Walcott (in part) [not Hall and Whitfield], 1891, Tenth Ann. Rept. U. S. Geol. Survey, p. 607, PL LXVII, figs. 2c-d (not figs. 2, 2a-b). (Mentioned. Figs 2c and 2d are copied from Walcott, 1886b, PL VIII, figs. 4c and 4b, respectively. The specimens represented by figs. 2c and 2d are redrawn in this monograph, PL XXIV, figs. 4 and 4a, respectively. The specimens represented by figs. 2, 2a-b, and 2e are referred in this monograph to Obolus (Westonia) ella.) Lingulella eUla Hall and Clarke (in part) [not Hall and Whitfield], 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, p. 58, fig. 20 (not figs. 19 and 21). (Mentioned in the text. Fig. 20 is copied from Walcott, 1891a, PL LXVII, fig. 2c. The specimens represented by figs. 19 and 21 are referred in this monograph to Obolus ( Westonia) ella.) OBOLID^. 495 Oholus (Lingulella) dubius Walcott, 1898, Proc. U. S. Nat. Mus., vol. 21, p. 401. (Described and discussed esaen- tially as below as a new species.) Lingulella genei Pack, 1906, Jour. Geology, vol. 14, No. 4, p. 295, PI. I, figs. 3, 3a-b. (Described and discussed as a new species.) This is a small shell associated with Oholus ( Westonia) ella (HaU and TMiitfield). It occurs in the form of casts in argillaceous shale, no traces of the shell substance remaining. The ventral valve averages about 3 mm. ia length, and the dorsal valves are a httle shorter. A cast of the interior of the ventral valve shows the visceral cavity (v), and an unusually strong main vascular sinus (vs) on each side. Only one specimen shows these characters as illustrated by Plate XXIV, figure 4; others only faintly indicate them. This dorsal valve is rounded ovate, and the cast of its interior shows a very short area that extends well out on the cardinal slopes. The interior markings are a portion of the main vascular sinuses, which, in their form and extension, somewhat resemble those of the dorsal valve of 0. ( W.) chuarensis (Walcott). The only muscle scars preserved are the anterior laterals of the dorsal valve. As far as can be determined from the casts, the outer surface is marked by hnes of growth and fine, slightly undulating concentric striae. Observations. — At first I thought the specimens now referred to this species were the young Oholus {Westonia) ella, and so illustrated them [1891a, PI. LXVII, figs. 2c and 2d]. There is still considerable doubt as to their specific relations, but in view of the very distinct interior markings I have referred them to a new species. The form described by F. J. Pack [1906, p. 295] as "Lingulella genei" comes from the same locaHty and band of shale as L. duhia, and has the same form and strong interior markings. Some of Pack's specimens show the cast of the exterior surface. This is marked by the very fine, concentric, sHghtly undulating lines so typical of Lingulella. The best-preserved casts of the surface do not present the characteristics of the surface of Oholus ( Westonia) ella. Formation and locality. — Middle Cambrian : (31) Shales at the CMsholm mine, southwest slope of Ely Mountains; and (333 [Pack, 1906, p. 295]) shales on the dump of the Abe Lincoln mine; both near Pioche, Lincoln County, Nevada. • . Lingulella .ELLSi (Walcott). Plate XIX, iigui-es 3, 3a-c. Obelus (Lingulella) ellsi Walcott, 1898, Proc. U. S. Nat. Mus., vol. 21, p. 402. (Described and discussed as below as a new species.) Shell small, broad ovate in outhne, with the ventral valve obtusely acuminate, and the dorsal valve broadly rounded; valves appear to have been moderately convex, judging from their appearance in the siliceous shale. The surface of the shell is marked by rather strong, concentric lines and strife of growth, the striae apparently indicating a slightly lameUose surface; very line radiating striae occur on the surface of the inner layers of the shell. A ventral valve 3.5 mm. in length has a width of 2.75 mm.; the dorsal valve is a little shorter than the ventral valve. Partial casts of the interior of the ventral valve show a very clearly defined area that extended as a shelf on each side of the rather deep, narrow, pedicle furrow; portions of the casts that fill the undercut may be observed in several specimens ; the flexure hnes are narrow, shaip, and situated well out toward the lateral margins. The cast of the visceral area of the ventral valve extends about one-third the distance from the area to the anterior margin; it is not well defined, and no traces of muscle scars have been detected; of the vascular system only the base of the main sinuses is shown in any of the casts. Observations. — This very pretty httle species is closely related in form to Lingulella rotunda (Matthew), and comparison should also be made with the more rotund variety of L.ferruginea Salter. It occurs in association with AcrotJiele pretiosa (Billings). 496 CMffiRIAN BRACHIOPODA. The specific name is given in lionor of Dr. R. W. Ells, whose fine work on the geology of a portion of the Province of Quebec unraveled the stratigraphic relations of the Lauzon slates in which the species occurs. Doctor Ells guided me to the locality at which the species occurs. Formation and locality. — Ordovician: (220a) Shales of the "Upper Sillery" ('Lauzon of Logan), on Chaudiere River at the Grand Trunk railroad bridge, Province of Quebec, Canada. LiNGULELLA FERRUGINEA Salter. Plate XXIX, figures 1, la-w, 2, 2a-f ; Plate XXX, figure 1; Plate XXXI, figures 3, 3a-c; Plate XXXV, figures 4, 4a-b. Lingulella unguiculus Salter, 1866, Rept. British Assoc. Adv. Sci. for 1865, p. 285. (Mentioned in a list of fossils from the "Menevian group.") Lingulella femiginea Salter, 1867, Quart. Jour. Geol. Soc. London, vol. 23, pt. 1, p. 340, fig. 1. (Described by Salter as a new species in the paper by Salter and Hicks, see p. 497 for copy. Fig. 1 is reproduced in this monograph, PI. XXIX, fig. 2b.) Lingulella ferruginea ovalis Hicks, 1867, idem, p. 341, figs. 2 and 3, p. 340. (Characterized by Hicks as a new variety, and discussed by Salter and Hicks, in the paper by Salter and Hicks. Figs. 2 and 3 are reproduced in this monograph, PL XXIX, figs. 2 and 2a, respectively.) Lingulella fenuginea Salter, Davidson, 1868, Geol. Mag., vol. 5, pp. 306-307, PL XV, figs. 1-8. (Described and dis- cussed. Figs. 7a and 6a are reproduced in this monograph, PL XXIX, figs. 2c and 2d, respectively.) Lingulella ferruginea ovalis Hicks, Davidson, 1868, idem, p. 307. (Mentioned in discussion of L. ferruginea.) Lingulella ferruginea Salter, Davidson, 1871, British Fossil Brachiopoda, vol. 3, pt. 7, No. 4, pp. 336-337, PL XLIX, figs. 32-35. (Described and discussed, see p. 497 for copy of part of discussion. Figs. 35a and 33a are repro- duced in this monograph, PL XXIX, figs. 2e and 2f, respectively.) Lingula or Lingulella sp. Linnarsson, 1876, Bihang till K. svensk. Vet.-Akad. HandL, Bd. 3, No. 12, pp. 15-16, PL III, figs. 24-28. (Described and discussed in English. Fig. 28 is reproduced in this monograph, PL XXXI, fig. 3c.) Lingulella sp. undt. Linnarsson, 1879, Sveriges Geol. Undersokning, Afhandl. och uppsatser, Ser. C, No. 35, p. 25, PI. Ill, figs. 38 and 39. (Described in Swedish.) Lingulella ferruginea Salter, Salter and Ethbridge, 1881, Mem. Geol. Survey Great Britain, vol. 3, 2d ed., p. 538. (Occurrence mentioned.) Lingulella ferruginea Salter, Davidson, 1883, British Fossil Brachiopoda, vol. 5, pt. 2, PL XVII, fig. 35. (No text reference.) Lingula ? dawsoni Matthew, 1884, Manuscript name requested by Walcott. Lingula ? dawsoni Matthew, Walcott, 1884, Bull. U. S. Geol.' Survey No. 10, p. 15, PL V, fig. 8. (Described and dis- cussed as a new species, see p. 497 for copy. The specimen represented by fig. 8 is redrawn in this monograph, PL XXIX, fig. Id.) Lingulella dawsoni Matthew (in part), 1886, Ti'ans. Roy. Soc. Canada for 1885, vol. 3, sec. 4, No. 3, pp. 33-34, PL V, fig. 9d (not figs. 9, 9a-c). (Described and discussed as a new species, but refers in synonymy to preceding reference. The specimen represented by fig. 9d is redrawn in this monograph, PL XXIX, fig. 1. The speci- mens represented by figs. 9, 9a-c are referred in this monograph to Lingulella martinensis.) Lingulella lingulcyides Matthew, 1886, idem, p. 34, PL V, figs. 8, 8a-b. (Described and discussed as a new species. The two specimens represented by figs. 8, 8a-b are redrawn in this monograph, PL XXIX, figs la, lb, and Ic, respectively.) Obolella? gemmula Matthew, 1892, Trans. Roy. Soc. Canada for 1891, vol. 9, sec. 4, No. 5, pp. 41-42, PL XII, figs. 8a-c. (Described and discussed as a new species. The specimens represented by figs. 8b and 8c are redrawn in this monograph, PL XXIX, figs, lu and Iv, respectively.) Lingulella dawsoni (Matthew), Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, p. 58, PL II, fig. 5. (Mentioned in text. Fig. 5 is drawn from the specimen figured by Matthew, 1886, PL V, fig. 9d.) Lingulella ci. ferruginea Salter, Kaysee, 1897, Zeitschr. Deutsch. geol. GeselL, Bd. 49, Heft 2, No. 2, p. 280, PL VII, fig. 7. (Characterized and discussed in German. Fig. 7 is reproduced in this monograph, PL XXX, fig. 1.) Obolus (Lingulella) gemmulus (Matthew), Walcott, 1901, Proc. U. S. Nat. Mus., vol. 23, p. 673. (Merely changes generic reference.) Leptobolus cf. linguloides Matthew, 1902, Bull. Nat. Hist. Soc. New Brunswick, vol. 4, pt. 5, No. 20, p. 407. (De- scribed.) Leptobolus linguloides Matthew, 1902, idem, p. 407. (Merely changes generic reference.) Lingulella ferruginea Salter, Matthew, 1903, Geol. Survey Canada, Rept. Cambrian Rocks Cape Breton, p. 108. (Dis- cussed in description of "Leptobolus atavus.") Leptobolus gemmulus Matthew, 1903, idem, pp. 190-192, PL XIV, figs. la-c. (Original description, Matthew 1892, p. 41, copied, revised, added to, and discussed.) Leptobolus cf. linguloides Matthew, 1903, idem, pp. 192-193. (Copy of Matthew, 1902b, p. 407.) Leptobolus linguloides Matthew, idem, p. 193. (Merely changes generic reference.) OBOLIDiE. 497 The original description by Salter [Salter and Hicks, 1867, p. 340] is as follows; Length fully 2.5 lines. Form ovate-oblong, the front rather obtuse, but not straight edged; the sidea nearly parallel; the obtusely pointed beak includes an angle of about 75°. Generally convex, especially down the median area; the sides beveled obliquely; the sm-face concentrically and very finely striated; the inner surface rather coarsely Bulcate concentrically, indicating close ridges or sharp waves of growth upon the outer surface (not visible in our specimens). The inner surface (and probably the outer) shows radiating lines (rather coarse ones) over the median area, but not on the sides. The pedicle groove is so wide and pyramidal as to open at an angle of 40° ; and its edges are so strongly pronounced as to give the appearance of hinge plates. A short median ridge divides this area, and extends but a very short distance. A specimen, apparently of the shorter valve, has also a median line, but fainter and longer. This is uncertain, the specimen being much crushed. The foregoing description was followed by a description of a variety named ovalis by Hicks [Salter and Hicks, 1867, p. 341]. It was collected in the Red Rocks of the Menevian group near St. Davids, and the varietal name was given to it on account of the front edge being "rounded off, and not squared at all." Davidson [1868, p. 307] stated that he did not consider this character of any importance, as he had before him specimens of L. ferruginea of a similar size which had the front quite as much rounded off. Davidson [1868, p. 307] also states that there can be no doubt as to the shell termed Lingulella unguiculus by Salter in 1865 being the same species as L. ferruginea described in 1867. He also states that it is true that L. ferruginea, Uke most of its congeners, varies sUghtly in its shape in different examples; some having their front and middle more rounded than others, and the posterior portion conyerging rather more in some individuals than in others. Davidson [1871, p. 336] further observes that — this small species has been correctly described and illustrated by Mr. Salter; and is, as far as we are aware, the earliest brachiopod hitherto discovered; for specimens [Davidson, 1871, PI. XLIX, fig. 35] were found by Hicks at the middle and the very base of the purple and red rocks of Sedgwick's "Harlech group," which dh-ectly underlies the "Menevian group" or lowest Lingula flags. The position is about 1,200 feet (365.8 m.) lower in the series than the specimen described by Salter and Hicks [1867, p. 340]. The shell does not appear to be scarce, but the beds are much cleaved, and their color is not in any way favorable to the exhibition of the characters of so thin a shell. In my remarks [1884a, p. 15] upon the species "Lingula f dawsoni " Matthew, I called atten- tion to the close resemblance between that species and Lingulella ferruginea, and said that with only a specimen of the ventral valve for comparison it was difficult satisfactorily to determine the specific relations of the species. With the large collections now before me from Newfoundland, and Matthew's and our own specimens from New Brunswick, it is possible to refer the form that has been described as Lingula? dawsoni to Lingulella ferruginea. Before making comparisons between the American and Welsh representatives of the species described, I will quote the original description of L. dawsoni [Walcott, 1884a, p. 15], and add such additional data as the specimens from the other collections of Newfoundland have afforded: Shell small, broadly subelliptical, subattenuate toward the beak; the margins gradually expanding and curving from the beak to the center, where the shell has its greatest width, and thence narrowing toward the front, which is broadly rounded. General surface depressed, convex, becoming more convex toward the beak. Surface marked by fine undulating concentric lines crossed by radiating lines that are seen only by the aid of a strong magnifying glass. In form this species approaches Lingulella ferruginea Salter of the Menevian fonnation of Wales quite closely, but with only a specimen of the ventral(?) valve to compare with it, it is difiicult satisfactorily to determine its specific relations. From the Newfoundland material the following additional description is taken: The dorsal valve is ovate and moderately convex as it occurs in the shale. The shell appears to have been thin, and built up of two or more layers or lameUse. The surface described for the type specimen is correct for the surface when the thin outer layer is exfohated. The outer surface, as shown by a small bit of it on the type specimen, is of the 62667°— VOL 51, pt 1—12 32 498 CMffiRIAN BRACHIOPODA. same general character as that of Lingulella radula Matthew and Lingulella mariinensis Matthew. It is exceechngly fine and is discernible only with a strong magnifier. The surface of a specimen represented by Plate LXIX, figure It, is marked, m addition to the radiating and concentric lines, by hregular, more or less transverse lines that suggest the surface of species referred to the subgenus Westonia. Associated specimens do not show this peculiarity of surface. The interior of the dorsal valve is not well shown. In two specimens (PL XXIX, figs. 1 and 1 1) traces of the visceral area are preserved, and the area and pedicle groove are indicated in figure If. In the casts of the dorsal valve the area is clearly defined (fig. In) and the trans- median (i) and the central muscle scars (h) (fig. Iq). The main trunk of the vascular sinus is far out toward the margins (fig. Ir), and in the same interior the paths of advance of the muscle scars are unusually prominent. A median sinus appears to be indicated in figure In. Oiservations. — Tlirough the courtesy of Dr. Gilbert D. Harris I have been able to com- pare the type specimen of "Lingula ? dawsoni," which belongs to the Hartt collection of Cornell University, with the specimens referred to the species by Matthew. Only one of Matthew's specimens [1886, PI. V, fig. 9d] belongs to the species. Two other specimens, however, described and figured as " Lingulella linguloides" [Matthew, 1886, p. 34], are undoubtedly specifically iden- tical with the original type of " Lingula? dawsoni," Matthew's identification being based on the figure of the specimen described and illustrated by me [1884a, p. 15]. Two other specimens illustrated by Matthew [1886, PI. V, figs. 9, 9a-c] as " Lingulella dawsoni" appear to be identical with L. martinensis Matthew. Both the ventral and dorsal valves of the two figured specimens are broken away at the beak, and allowance is also made for their being compressed in shale, while the types of L. martinensis are embedded in sandstone. It will be noticed that our Plate XXIX, figure 1, differs from Matthew's figure 9d [1886, PI. V] in the form of the visceral area, although they are drawn from the same specimen. The shell is small, and the markings are somewhat indistinct, but from what may be seen and from our knowledge of the form of the markings in the closely related species, I think the change in the figure is necessary. A shell that appears to be identical with this species occurs in the compact, gray, thin- bedded sandstones that are interbedded in the Upper Cambrian shales on McNeil Brook, 1.5 miles (0.94 km.) east of Marion Bridge, Cape Breton, Nova Scotia. The species is abun- dantly represented, the partings of the shaly sandstone often being nearly covered with the detached valves. The average length of the ventral valve is 3 mm. Lingulella ferruginea occurs in abundance in the shales and interbedded limestones of the Manuels Brook section, Newfoundland, and also in the dark shales above the Lower Cambrian beds near Topsail Head, on the shore of Conception Bay. In order to exliibit the range of variation caused by the character of the embedding matrix, a number of specimens are illus- trated. Plate XXIX, figures le to Ik, and In, are from the shales; figures If, li, Ij, and Ik show the effect of compression and distortion, while figures 1 1, Im, lo, Ip, and Iq, from the limestone, are more convex and regular, although the specimens they represent were chosen as illustrating variation in form. In the Manuels Brook section, Newfoundland, Lingulella ferruginea is associated with Acrotreta misera, Agnostus punctuosus, Microdiscus punctatus, Paradoxides davidis, P. hicksi, Anopolenus venustus, ConocorypJie elegans, Otenocephalus matthewi, Erinnys venulosa, Ptycho- paria robbi, P. variolaris, HolocepTialina inflata, Agraulos socialis, etc. [Walcott, 1891b, p. 261]. Davidson [1868, p. 306] gives a fist of the fossils that occur in association with Lingulella ferruginea in the Menevian group of Wales. Among them we find Paradoxides davidis, P. Tiicksi, Erinnys venulosa, PtycJioparia variolaris; also the genera HolocepTialina and Anopolenus. The above-mentioned association of species ra the Newfoundland and Welsh beds shows that Lingulella ferruginea occurs in the same relative faunal horizon on the two sides of the Atlantic. A comparison of the illustrations of the type specimens [Salter and Hicks, 1867, figs. 1-3] and those subsequently described and illustrated by Davidson [1871, PI. XLIX, figs. 33 and 35] shows clearly that there are no true specific difl'erences between the two species. OBOLID^. 499 In order to place these clearly before students, the original figures of Salter [Salter and Hicks, 1867, figs. 1-3] and Davidson [1871, PI. XLIX, figs. 33 and 35] are reproduced on Plate XXIX. "Leptobolus gemmulus" Matthew [1903, p. 190] appears to be a true Lingulella and specific- ally identical Avith L. ferruginea. It occurs at a higher horizon (Division 3c of Matthew's sec- tion) than the tj'pical forms of the latter in Wales and near St. John, New Brunswick, but that is not surprismg for a species which has so wide a geograpMc distribution. Only one specimen from the tj'pe locality at Xa^'y Island, St. John, sent to me by Matthew, shows the area and central groove of the ventral valve. In tli3 sliales of his Division C3e on McLeod Brook, Cape Breton, Matthew collected a fine series of compressed and flattened shells that he referred to "Leptobolus gemmulus." These shells appear to have the broad form as the result of being flattened in tlie shale. The same changes occur in typical specimens of L. ferru- ginea when flattened in the shales at Andrarum, Sweden. In the interbedded limestones they are narrower and more convex. I note the same differences also in specimens from the shaly sandstones of IMcNed Brook, Cape Breton. The narrow, uncompressed forms are shown by Plate XXXY, figures 4, 4a-b. In the same sandy shales occur flattened shells that are as broad as those referred to " Leptoholus gemmulus" Matthew [1903, p. 190] (PL XXIX, figs. lu and Iv). Lingulella lepis Salter, when uncompressed, has the broad form given to L. ferruginea by compression, and would be compared with Matthew's "Leptobolus gemmulus" if the latter were retained as a species. A species that appears to be identical with this occurs at Hastings Cove, St. John County, New Brunswick, and a closely aUied form, compared by Matthew [1895a, p. 115] with Lingulella granvillensis, occurs m the "Protolenui beds" of Hanford Brook, St. Jolm County, New Brunswick. Linnarsson [1876, PI. Ill] gives several illustrations of a small LAngulella from the Para- doxides beds. One of them (see PI. XXXI, fig. 3c) is an elongate form that may represent a distinct species from the broader forms represented by Plate XXXI, figures 3, 3a, and 3b in this monograph. A direct comparison between specimens from the hmestones of Sweden and Newfoundland leads to the conclusion that they belong to the same species. Kayser [1897, PI. VII, fig. 7] illustrates a species of Lingulella from Iruya, northern Argentina, that he compares with L. ferruginea Salter. It certainly resembles that species verj^ closely, and with our present knowledge of the Avide distribution of L. ferruginea, I believe we are justified in identifying the South American form as the representative of that species. The figure given by Kayser [1897, PI. VII, fig. 7] is reproduced on Plate XXX. The associated species given by Kayser [1897, pp. 277-281] are Liostracus ulricTii, L. steinmanni, L. sp., Agnostus iruyensis, Lingulella cf . davisi, and OrtMs saltensis. Formation and locality.^ — Upper Cambrian: (3h) Shale and shaly limestone on McNeil Brook, 1.5 miles (2.4 km.) east of Marion Bridge; (307 [Matthew, 1903, p. 192]) shales of Division C3c of Matthew, on McLeod Brook (=Bara- chois River); and (307a [Matthew, 1903, p. 240]) shales of Division C3c2 of Matthew, on McLeod Brook (=Barachoi8 . River), near Boisdale; all in eastern Cape Breton, Nova Scotia, Canada. (308 [Matthew, 1892, p. 41]) Shales of Division C3c of Matthew at Navy Island, St. John Harbor, St. John County, New Brunswick, Canada. (3) Shaly limestones 300 feet (91.4 m.) above the Paradoxides zone, Manuels Brook, Conception Bay, Newfound- land. (310d) Ceratopyge slate at Borgholm, Oeland Island, Sweden. (389d [Kayser, 1897, p. 280]) Iruya, Province of Salta, Argentina, South America. Middle Cambrian: (3i) Compact, fine-grained, thin-bedded, gray sandstone of the Paradoxides zone, on McLean Brook, 1 mile (1.6 km.) east of McCodrum Brook, and 1.5 miles (2.4 km.) west of Marion Bridge, eastern Cape Breton, Nova Scotia, Canada. (2s) Limestone in upper part of Paradoxides zone, at Hastings Cove [Matthew, 1898b, p. 38], on Kennebecasis Bay, 0.5 mile (0.8 km.) northeast of Torryburn, on the Intercolonial Railway northeast of St. John; (2i) sandstones of Division lb3 of Matthew's [1895a, p. 108] Protolenus zone, on Hanford Brook; and (21) limestone at the base of the Paradoxides zone [Matthew, 1895a, p. 108]; all on Hanford Brook, St. John County, New Brunswick. (301 1) Shales of Division Id of Matthew on Porters Brook, St. Martins; (2m) shales near the base of the Paradoxides zone on Hanford Brook; (301k) St. John formation in the city of St. John; (301h) shales of Division Ic of Matthew, on Hanford Brook; (301g) sandstones of Division Ic of Matthew, at Portland (now a part of the city of St. John); and a This species also occurs at Localities 318u and 3187, p. 249. 500 CMIBRIAN BRACHIOPODA. (301z) in Division Ic of Matthew at Ratcliffs Millstream; all [Matthew, 1886, p. 34] in St. John County, New Brunswick. (la, 6 1, and 6n) Shales near the top of No. 6 of the Manuels Brook section ; (6r and 6u) limestone and shale, respec- tively, on the west side of Manuels Brook; (1) shales of zone A of No. 7 of the Manuels Brook section; and (2) shales of zone B of No. 7 of the Manuels Brook section; all on Manuels Brook [Walcott, 1891b, p. 261], Conception Bay, Newfoundland. (2a) Shales ft-om same horizon as No. 1, Topsail Head, Conception Bay, Newfoundland. (6g) Limestone near the base of the Middle Cambrian, the lowest horizon carrying Paradoxides, northwest side of Chappie Arm Harbor, about 1 mile (1.6 km.) from its head. Trinity Bay, Newfoundland. (318j [Salter, lS66b, p. 340]) Black shales of the Menevian group at Pen-y-pleidiau, St. Davids; (318h) shales in the Mene\'ian at St. Davids; (318o) " red shales at the base of the Harlech grits at Solva; (366b) red shales at the base of the Harlech grits at Porthclais Harbor, south of St. Davids; and (318n)o red shales at the base of the Harlech grits at St. Davids; all in South Wales. (318e)a Lower portion of the Menevian at Camlan; (318k)a in the Menevian rocks at Tafern Helig; (3181)o in the Menevian rocks at the Waterfall Valley, near Maentwrog; all in North Wales. (8w) Limestones of the Paradoxides forchhammeri zone, at Andrarum, 20 miles (32.2 km.) northwest of Simri- shamn, Province of Christianstad ; (310q) limestone of the Agnostus Ixvigatus zone at Lovened, Province of Skaraborg; (320m [Linnarsson, 1876, p. 15]) limestones of the Paradoxides forchhammeri zone at Kinnekulle, Province of Skaraborg; (320n [Linnarsson, 1876, p. 16]) limestones of the Paradoxides forchhammeri zone at Lovened, Djupadal, 19 miles (30.6 km.) south-southeast of Skara, Province of Skaraborg; (310m [Linnarsson, 1876, p. 16]) arenaceous shales of the Para- doxides tessini zone on Oeland Island; (310o) limestone of the Paradoxides tessini zone at Borgholm, Oeland Island; (310p) limestone of the Paradoxides mlandicus zone at Borgholm, Oeland Island; (310y) limestone at Kiviks Esperod, Province of Malmohus; and (310z) limestone at Brantevik, on the shore a little south of Simrishamn, Province of Christianstad; all in Sweden. (16h) Limestones of the Paradoxides forchhammeri zone at Borregaard; and (16j) limestones of the Paradoxides forchhammeri zone at Laesaa; both on Bornholm Island, Denmark. (324d) Windjuelandet, Ringsaker, Province of Hedemarken, Norway. Tliis species is somewhat doubtfully identified from the following localities: Upper Cambrian: (6s) Just north of Fosters Point, Random Island, Random Sound, Newfoundland. Middle Cambrian : (i) Shales of zone A of No. 7 of the Manuels Brook section [Walcott, 1891b, p. 261], Manuals Brook, a small stream which flows into Conception Bay from the east, near Topsail Head, Newfoundland. (2i) Sandstones of Division lb3 of Matthew's [1895a, p. 108] Protolenus zone, Hanford Brook, St. John County, New Brunswick. LiNGULELLA cf. FERRUGINEA. Plate XXX, figure 4. ' . Lingulella (?) sp. Pompeckj, 1896, Jahrb. K.-k. geol. Reichsanstalt, Bd. 45, Hft. 3, p. 509, PI. 'XIV, figs. 16a-b. (Described in German; see below for translation. Figs. 16a-b are reproduced in this monograph, PI. XXX, fig. 4.) The original description by Pompeckj is as follows: There is on hand a ventral valve which, owing to its bad state of preservation, can not be assigned to the genus Lingulella otherwise than doubtfully. Outline elongated, pentagonal with corners rounded off. The length is somewhat more than double the breadth. The vertex (beak?) is drawn far forward. The surface shows a concentric striation. In front of the vertex (beak?) is seen a short median gi-oove. The form recalls Lingulella (?) sp. undt., which Linnarsson [1876, p. 15] described from Kinnekulle; but it ia more slender than the species made known from the Paradoxides slate of Sweden. This httle shell is probably the representative of Lingulella ferruginea Salter of the English and Swedish Paradoxides fauna. Formation and locality. — Middle Cambrian: (345 [Pompeckj, 1896b, p.. 509]) Greenish shales in the Paradoxides zone on the Dlouhd Hora, above the brook of Sbirov, near Skrej, Bohemia, Austria-Hungary. Lingulella flumenis (Matthew). Plate XXXV, figures 6, 6a-b. Leptobolus flumenis Matthew, 1903, Geol. Survey Canada, Rept. Cambrian Rocks Cape Breton, pp. 189-190, PL XI, figs. 7a-f. (Described and discussed as a new species; see p. 501 for copy. The specimens represented by figs. 7a, 7b, and 7e are redrawn in this monograph, PI. XXXV, figs. 6, 6a-b, respectively.) a Davidson, 1871, p. 337. OBOLID^. 501 The original description by Matthew is as follows : A narrowly ovate species, somewhat straight on the sides, and broadly rounded in front. The ventral valve has an obtusely pointed beak, bent down at the apex. Sides of the valve somewhat sharply sloped in the posterior half and gently sloped in front. Interior. — This shows an area nearly half a millimeter long, and a visceral callus extending about half the length of the valve. The lateral ridges within the valve extend as far; and in front of them, reaching to within a sixth of the length of the valve from the front, is a pair of arched vascular grooves not far fi-om the margin of the valve; numerous external branches from these trunk grooves extend to the flattened margin of the valve. The individual length of these branches is about equal to the width of the main groove. The dorsal valve is obtusely rounded at the hinge area, which is very short, and here and at the sides the valve is strongly arched downward, but is gently sloped down in front. Interior. — In front of the linear cardinal area is a pair of pits marking the insertion of the cardinal muscles. The middle of the valve for more than half the valve's length has a flattened band marking the progress of the central muscles during the growth of the shell. At the front this band is about one-sixth or one-eighth of the width of the valve, and at its sides are faint prints of the central muscles; and at the front are two pairs of minute pits, one or both of which marks the position of the anterior laterals. The place of the posterior laterals is marked by a series of small pits near the margins in the posterior third of the valve. In front of these pits are the strong arched grooves left by the vascular trunks, which extend across the middle half of the valve near its margins. No examples have been obtained showing the surface markings, except those near the front of the valve; but both valves show from four to six ridges of gi-owth in the anterior quarter of the valve. These ridges are broadly curved in the middle part, but more abruptly at the sides. Ventral valve 4 mm. long and 2.5 mm. wide. The dorsal valve is nearly one-half millimeter shorter than the ventral. This species is of nearly the same size as L. insulse, but is less elliptical in outline, and the valves are more flat- tened in front; the area of the ventral valve also is longer, and that of the dorsal shorter than in that species; also the central group of muscles is not set so far forward as in that of the dorsal of the species cited. This species differs fi-om L. atavus of the Etcheminian terrane in having the central muscles of both valves set fai'ther back. The exact horizon of this species is uncertain, as the outcrop is in an isolated basin [Mat- thew, 1903, p. 51]. Matthew correlated it with his section on the lithologic character of the matrix. The form is very much hke that of Lingulella collicia (Matthew), and it appears to ' be identical with small shells of the latter species. Formation and locality. — Middle Cambrian: (325a [Matthew, 1903, p. 190]) Shales of Division C2c of Mat- thew's [1903, p. 49] Bretonian on the eastern slope of the valley of McNeil Brook, on the road to Trout Brook, in the Mira River valley, eastern Cape Breton, Nova Scotia. Lingulella franklinensis (Walcott). Plate XXVI, figures 3, 3a-b. Obolus {Lingulella) franklinensis Walcott, 1898, Proc. U. S. Nat. Mus., vol. 21, pp. 404-405. (Described and dis- cussed essentially as below as a new species.) Shell small, ovate, moderately convex, with the apex of the dorsal valve subacuminate. Surface of the shell marked by rather strong hnes and strise of growth, with very fine, shghtly irregular, wavy striae between the coarser concentric strise. Two ventral valves referred to this species have a length of 3 and 3.5 mm., respectively, with a width of about 2.75 mm. There are no dorsal valves in the collection. A partial cast of the interior of the shell carries an impression of radiating striae, a strong cast of a narrow pedicle furrow, and a few concentric Hnes of growth. If the shell represented by Plate XXVI, figure 3b, belongs to this species, the interior surface was also marked by scattered bits of punctse. Observations. — This species is founded on three specimens of the ventral valve that occur in the Umestones interbedded in dark shales above the Lower Cambrian Olenellus-hesLTing shales. A larger shell (PI. XXVI, fig. 3b) has the same surface characters and occurs at the same relative geological horizon, and it may belong to this species; the only specimen of it in the collection is apparently a dorsal valve. The exact stratigraphic horizon has not been determined, but from the associated species of Agnostus and Ptychopana it appears that the reference should be to the Middle Cambrian. 502 CMIBRIAN BRACIIIOPODA. The material for stud}^ is so limited that it is difficult to make comparisons with other species. In form the ventral valve resembles that of Lingulella lineolata (Walcott) (PI. XIjVIII), L. tarpa (Walcott) (PI. XXIII), and in some respects L. granvillensis Walcott (PI. XXII), -with which it would be more naturally compared owing to its belonging to the Appalachian fauna. The specific name is derived from Franldin County, Vermont, in which the species occurs. Formation and locality. — Middle Cambrian: (28a) "St. Albans formation, " in limestone lentil about 1 mile (1.6 km.) east of Parker's quarry, west of Georgia; (319v) sandy shale, 2 miles (3.2 km.) east of Highgate Springs; and (87) conglomerate limestone 1 mile {1.6 1cm.) south-southwest of Highgate Falls; all in Franklin County, Vermont. Lingulella fuchsi Redlich. Plate XXXIX, figures 2, 2a-c, 3. Lingulella fuchsi Redlich, 1899, Mem. Geol. Survey India, Paleontologia Indica, new ser., vol. 1, No. 1, Cambrian Fauna of the Eastern Salt Range, p. 7, PI. I, figs. lOa-e. (Described and discussed as a new species. Fig. 10c is reproduced in this monograph, PI. XXXIX, fig. 3.) Obolus (Lingulella) fuchsi (Redlich), Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 332. (Discussed somewhat aa below.) In the collection of fossils received from Doctor Noetling I find, associated with Lingulella wanniecJci Redlich, a small elongate form that appears to be identical •with. L. fuchsi of Redlich. Redlich states [1899, p. 10] that his L. fuchsi occurs in a hard clay above the lower magnesian sandstones which rest on the shales containing L. wanniecJci. If my identification of the species is correct, L. wanniecki has a greater vertical range, or there may have been some error in the identification and labeling of the zone from which the original specimens were obtained. The identification of the species in the material before me is based on the form of the ventral valve, as shown by Redlich's figure 10c [1899, PI. I] and my figure 2 (PI. XXXIX). The dorsal valves represented by Plate XXXIX, figures 2a-c, differ materially from Redlich's illustration; but in the specimen represented by figure 2d the little pit mentioned by RedHch [1899, p. 7] is shown, also two ridges that leave a concave furrow in the central portion of the cast of the valve. These are the lines of the main vascular sinuses. Formation and locality. — Middle Cambrian: (15r)a Dark argillaceous shale, at Khussak, Salt Range, India. Lingulella grandis (Matthew). Plate XXXVIII, figures 2, 2a-f. Leptoholus grandis Matthew, 1894, Trans. Roy. Soc. Canada for 1894, 1st ser., vol. 11, sec. 4, No. 8, pp. 91-92, PL XVI, figs. 7a-c. (Described and discussed as a new species. The specimens represented by figs. 7a and 7b are redrawn in this monograph, PL XXXVIII, figs. 2b and 2f, respectively.) Lingulella ? cuneata Matthew, 1894, idem, pp. 92-93, PL XVI, figs. 5a-b. (Described and discussed as a new species. Matthew's types of Lingulella cuneata are figured in this monograph, PL XXXVIII, figs. 2, 2a, 2c, and 2d, but it is impossible to tell which of these Matthew figured, PL XVI, figs. 5a-b.) Lingula cf. billingsiana ^^Tiiteaves, Matthew, 1894, idem, p. 93, PL XVI, figs. 6a-b. (Described and discussed.) Lingulella f billingsana Schuchert (in part) [not (Whitbaves)], 1897, Bull. U. S. Geol. Survey No. 87, p. 256. (Merely changes generic reference of Matthew's species Lingula cf. billingsiana cited above.) Not Leptobolus cf. grandis Matthew, 1902, Trans. Roy. Soc. Canada for 1902, 2d ser., voL 8, sec. 4, No. 3, p. 111. (Characterized. This species is given by Matthew as occurring -on Mount Stephen, British Columbia. For the species occurring at this locality see pp. 127-128.) General form subcuneate, with the ventral valve acuminate and the dorsal valve elongate- ovate; valves more than usually convex for a species of the genus. Surface of shell marked by concentric striae and strong Imes of growth, and, where the outer surface is perfect, by almost microscopic, irregular, semi-inosculating, elevated strise, that under a high power give the surface an appearance somewhat similar to that of Lingulella {Lingulepis) roierti (Matthew) and Obolus ( Westonia) ella (Hall and Whitfield) (PI. XLVII). In almost every instance this surface adheres to the matrix, leaving the glossy inner surface described by Matthew [1894, p. 92]; the inner layers or lamellae are marked by numerous fine radiating striae and concentric growth lines; a Specimens from the typo locality were given to the United States National Museum and this number was assigned to them. OBOLID^. 503 a iew large punctse were seen on the interior of one ventral valve. The shell is unusually thick for its size. It has a thin outer layer and several inner layers or lamellse that are arranged very much as in Lingulella acutangula (Roemer) (PI. XVII). A relatively large ventral valve has a length of 7 mm. and a %vidth of about 5.5 mm. The cast of the area of the ventral valve shows a long area divided midway by a narrow pedicle groove, and toward the lateral margins by a very narrow flexure line. The area of the dorsal valve is shorter in proportion than that of the ventral valve, and also less extended on the cardinal slopes. The cast of the visceral cavity (v), including the outline of the heart-shaped cavity (x), is very well shown by Plate XXXVIII, figures 2a and 2b. There are no traces of a median septum in the ventral valve, but in the dorsal valve it is a very narrow sharp crest on the summit of the broad, strong, median ridge that extends from the area fully three-fourths of the distance to the front margin; the septum appears to be confined to the anterior half of the length of the ridge. The muscle scars are not clearly defined in either valve. The trapezoidal areas of the ventral valve, where the central scars and the middle and outside laterals are usually located, are present, but the individual scars can not be differentiated. In the dorsal valve the central scars appear to be unusually large ; they are situated on each side of the broad median ridge, and crowd the parietal scar out to the main vascular sinus ; the anterior laterals are situated on each side of the median septum, as shown in Plate XXXVIII, figure 2d, but they are not well defined. The main vascular sinuses of the ventral valve extend far forward and curve inward so that they appear nearly to unite a short distance back of the anterior margin of the shell; their interior lateral branches appear to touch, and thus give the appearance of uniting the two main sinuses; the lateral branches extend outward from the main sinus nearly to the edge of the shell, while the interior lateral branches are crowded into the space between the main vascular sinuses and the visceral area. The main vascular sinuses of the dorsal valve extend well forward and curve inward toward the median line; their interior lateral branches fill the narrow space between the vascular cavity and the main sinuses; no traces have been observed of the peripheral branches of the vascular system of the dorsal valve. The parietal scar is shown more clearly for the dorsal than for the ventral valve. In the former it extends about the space occupied by the central scars, but it has not been traced outside of the main sinuses or in front of the anterior lateral muscle scars. Ohservations. — I was greatly puzzled when studying Matthew's figures [1894, PI. XVI] of "Leptoholus grandis, Lingulella? cuneata, and Lingula of. billingsiana." It seemed, after extended study of the character and variation of the interior markings of Oholus and Lingulella, that the three species should be referred to Lingulella and perhaps to one species. Doctor Matthew very kindly sent me liis material, including the type specimens of this species. At first I was inclined to consider "Leptoholus grandis" as distinct from Lingulella, but on close study it became more and more evident that the differences were such that a generic distinction could not be based upon" them. The anterior extension of the main vascular sinuses varies both in form and degree with different species of Lingulella. This may be seen by comparing Lingulella ampla (Owen), Lingulella acutangula (Roemer), etc. The position and size of the visceral area and muscle scars of the dorsal valve are also subject to great variation, as may be seen by comparing Lingulella acutangula, and L. ampla. All of the material of Matthew's "Leptoholus grandis, Lingulella f cuneata, and Lingula cf. hillingsiana" is from one locality and bed. It comprises a large number of shells on some twenty-seven pieces of rock. I found that there was more or less distortion of the shells by both vertical and lateral compression. Where the interior markings are well preserved the shells can be at once referred to Lingulella grandis. It is oidy in shells that are distorted or a little larger, or where the interior is imperfectly shown, that any doubt arises, and even in this case no undoubted dorsal valve was found that could be referred to any other species than L. grandis. The illustrations of "Lingulella? cuneata" [figs. 5a and 5b] and "Lingula cf. hillingsiana" [figs. 6a and 6b] by Matthew [1894, PL XVII are all of ventral valves, and the figures of "Leptoholus 504 CMIBRIAN BRACHIOPODA. grandis" [figs. 7a and 7b] are so diagrammatic that it is impossible to make comparisons between them and the dra\\Tngs of the same specimens which accompany this monograph. Formation and locality. — Lower Ordovician : (301s) Gray sandstones of Division 3e(?) of Matthew [1894, p. 91] at McAphee's corner, Hardingville, St. John County, New Brunswick. LlNGTJLELLA GRANVILLENSIS Walcott. Plate XXII, figures 1, la-d. Lingulella granviUensis Walcott, 1887, Am. Jour. Sci., 3d ser., vol. 34, pp. 188-189, PI. I, figs. 15, 15a-c. (Described and discussed as a new species. The specimens represented by figs. 15, 15a, and 15b are redrawn in this mono- graph, PI. XXII, figs. Ic, Id, and 1, respectively.) Lingulella granvillensis Waicott, Oehlert, 1889, Annuaire g^ologique universel for 1888, tome 5, p. 1138. (Described in French in a review of the preceding reference.) Lingulella granvillensis Walcott, 1891, Tenth Ann. Rept. U. S. Geol. Survey, pp. 607-608, PI. LXVII, figs. 4, 4a-d. (Description and figs. 4, 4a-c, copied from Walcott, 1887, p. 188, PL I, figs. 15, 15a-c.) Lingulella granvillensis Walcott, Hall and Glabke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, p. 58. (Discussed.) General form rather broadly ovate, with the ventral valve obtusely acimiinate and the dorsal valve obtusely oval. Valves moderately convex, the dorsal being somewhat more so than the ventral. Surface of shell marked by concentric lines of growth, with very fine, slightly undulating striae between them, and a few very indistinct radiating strise. The character of the surface of the inner layers and of the interior of the shell is unknown. The shell appears to have been rather thin and formed of a thin outer layer and one or more inner layers or lamellae. A rather large ventral valve has a length of 6 mm. and a width of 4.5 mm., and an asso- ciated dorsal valve 5 mm. in length has a width of 3.5 mm. The interior of a small ventral valve shows the visceral area and the two main vascular sinuses; on a cast of the dorsal valve the main vascular sinuses are shown, also a fine irregular network of interior branches of the main sinuses and a few peripheral branches of the vascular system. These are shown by Plate XXII, figure Id. A broad, low ridge, represented on the cast by a shallow depression, extends forward in front of the area two-thirds the distance toward the frontal margin. It is marked on the median line near the center of the shell by a sharp, narrow median septum, and lines indicating the path of advance of tlie central and anterior lateral muscle scars. The scars are not clearly defined, but appear to be situated as indicated on figure Id. In front of the anterior lateral muscle scars there is a peculiar rhomboidal area that is not so well defined in any other species. Observations. — This is one of the small species that in si2;e and general form resembles Lingulella ferruginea Salter of the Middle Cambrian of the Atlantic basin; also L. manticula (Wliite) of the Upper Cambrian and Lower Ordovician of the Rocky Mountain region; it differs from the former in its broader anterior outline and from the latter in its more acuminate form and shorter area. This form owes its specific name to the occurrence of the type specimen near Granville, New York. Formation and locality. — Lower Cambrian: ('20a) Gray limestone, interbedded with shaly slates, in a lane west of Lafayette Stevens's house, about 100 yards (91.4 m.) from the main road, in the southern part of '^'hitehall Township, Fort Ann quadrangle (U. S. Geol. Survey); (21a) limestone below the first fall of Mettawee River, above the North Granville bridge. Fort Ann quadrangle (U. S. Geol. Survey); (37b) limestones 0.25 mile (0.4 km.) east of Salem, Cambridge quadrangle (U. S. Geol. Survey); (38a) limestone 2 miles (3.2 km.) south of North Granville, on the first road luhich turns south from the road running between that village and Truthville, 4 miles (6.4 km.) west-northwest of Granville, Fort Ann quadrangle ( U. S. Geol. Survey) ; (34) limestone on roadside a little west of the bridge over Poultney River, at Low Hampton, about 5 miles (8 km.) east-northeast of 'WTiitehall, 'Whitehall quadrangle (U. S. Geol. Survey); (338m) limestone on the roadside north of schoolhouse No. 4, in the northeast part of 'Whitehall, 'Whitehall quadrangle (U. S. Geol. Survey); (35) limestone 1.5 miles (2.4 km.) north of Bald Mountain, and 3.5 miles (5.6 km.) north-northwest of Greenwich, Schuylerville quadrangle (U. S. Geol. Survey); (38) limestone 0.25 mile (0.4 km.) north of John Hulett's farmhouse about 3 miles (4.8 km.) west of South Granville, and 4.5 miles (7.2 km.) southwest of Granville, Fort Ann quadrangle (U. S. Geol. Survey); and (3381) limestone in OBOLID^. 505 the northern part of Easton Station, 3 miles (4.8 km.) south of Greenwich, Cambridge quadrangle (U. S. Geol. Survey); all in Washington County, New York. (29) Limestone just above the bridge at the Stockport paper mill, on Kinderhook Creek; and (441)) limeptone near North Chatham in the northern part of the Kinderhook quadrangle (U. S. Oeol. Survey): both in Columbia County, New York. (25a) Limestone on the Hall (Donaldson's) farm, 2 miles (3.2 km.) east of Swanton, Franklin County, Vermont. LiNGULELLA HAYESI (Walcott). Plate XXV, figures 1, la-j. Obolus (Lingulella) hayesi Walcott, 1898, Proc. U. S. Nat. Mus., vol. 21, pp. 405-406. (Described and discussed as a new species, essentially as below.) Shell small; general form broad ovate, Avith. the ventral valve obtusely acuminate and the dorsal valve rounded ovate; valves moderately convex. Outer surface as seen m casts marked by fine, concentric lines and strije of growth; the inner surface had fine, radiating strise and scattered pits or punctse. The shell appears from the, casts to have been of medium tliickness and built up of several layers or lamellae. The average length of the ventral valve is about 3.5 mm.; width about 3 mm. The dorsal valves are a little shorter than the ventral valves, the length and width being about the same, although some of the shells are a little wider than long. The casts of the interior of the ventral valve show a clearly defined, strong area, divided midway by the cast of a narrow pedicle groove, and again by sharp flexure lines situated a little nearer the pedicle groove than to the lateral margins. The strise of growth cross the area parallel -with its base, arcliing over the cast of the pedicle furrow. The area formed a thin shelf between the pedicle groove and the lateral margins, the undercut extending back under the area as shown in the cast by a thin projection of the embedding rock over the area. The area of the dorsal valve is of medium length and marked by strife of growth and rather clearly defined flexure lines. The cast of a ventral valve shows the visceral cavity and rather strong and long main vascular sinuses. In the dorsal valve the main vascular sinuses are frequently outlined very beautifully on the sfliceous casts; the visceral area surrounded by the parietal band is clearly defined, also the central and anterior lateral muscle scars, and in one cast the transmedian muscle scars. Observations. — This very pretty species occurs quite abundantly on the siliceous nodules embedded in the Conasauga ("Coosa") shale. It resembles in form Oholus lamborni (Meek) and Oholus vnllisi (Walcott), but is a much smaller species. The elongate visceral cavity of the dorsal valve is also of the same type as that of those species. The thickemng in front of- the visceral cavity (PL XXV, fig. lb) is similar to that which occurs in Oholus matinalis (Hall) (PI. V, fig. Id). In this character and in its broadly ovate form it comes very close to the forms which are referred to Oholus. The specific name was given in honor of Dr. C. W. Hayes, at that time chief geologist of the United States Geological Survey. Formation and locality. — Middle Cambrian : (90x and 94a) '^ In and attached to the outer surface of siliceous nodules in the Conasauga ("Coosa") shale, Coosa Valley, east of Center, Cherokee County, Alabama. Lingulella heberti Barrois. Plate XXXIX, figures 11, lla-c. Lingulella heberti Barrois, 1882, Mem. Soc. geol. du Nord, vol. 2, pp. 185-186, PI. IV, figs. 3a-d. (Described and discussed in French as a new species; see below for translation. Figs. 3a-d are reproduced in this monograph, PI. XXXIX, figs. 11, lla-c, respectively.) The original description by Barrois follows: Shell corneous, regular, elongated, slightly convex, scarcely inequivalve. Enlarged in the pallial region where the outline is rounded; pointed at the beaks; longer than wide. Marked with well-developed concentric lines of a 90x is the type locality. 506 CAMBRIAN BRACHIOPODA. growth, some of which are stronger than others. The shell is covered with small fine tubercles, in lines, like certain species of Kingena from the Cretaceous, and produced by the fine, oblique, granular striae. (PL XXXIX, fig. llc.)85 is the type locality, though the specimens in the United States National Museum collections to which that number is assigned were collected later than the type specimens. OBOLID^. 521 LiNGULELLA MOSIA OSCEOLA (Walcott). Plate XVIII, figures 2, 2a-c. Obolus (Lingulella) mosia osceola Walcott, 189S, Proc. U. S. Nat. Mus.> vol. 21, p. 409. (unaractenzed as below as a new variety.) There is a considerable variation in the form of Lingulella mosia (Hall) as it occurs in the brown sandstone of Osceola, and for the narrow, more elongate variety the name osceola was proposed [Walcott, 189Sb, p. 409]. It is an intermediate form between L. mosia and L. perattenuata (Whitfield) (PI. XXI). The same, or a closely allied, variety occurs in a light-colored sandstone at Eau Claire. The varietal name is derived from Osceola, the type locality. Formation and locaiitt. — Upper Cambrian: (78 and 78s)'' "8t. Croix sandstone" in quarry near St. Croix River, in suburbs of Osceola, Polk County, and (98) "St. Croix sandstone" near Eau Claire, Eau Claire County; both in Wisconsin. Lingulella nanno (Walcott). Plate XXIV, figures 1, la-d. Obelus (Lingulella) nanno Walcott, 1898, Proc. U. S. Nat. Mus., vol. 21, p. 409. (Described as below as a new species.) Shell very small; general form elongate ovate, with the ventral valve subacuminate to acuminate, and the dorsal valve elongate in outline. The convexity of the two valves is mod- erate in the very small shells, increasing slightly with the increase in size. Average length of the ventral valve is about 2 mm., and that of the dorsal valve a little less. The surface of the shell as it appears in the hard, fine grained, drab-colored limestone is marked by fine, concentric strife, and very faint traces of radiating striiB. Observations. — This minute species occurs in thin layers of limestone interbedded in the Conasauga ("Coosa") shale. Its small size and acuminate ventral valve distinguish it from other species. It is associated with Dicellomus appalachia Walcott and fragments of trilo bites. Formation and locality. — Middle Cambrian: (16) Conasauga limestone, Blountsville Valley, Blount County; and (91) Conasauga ("Coosa") shale at Cedar Bluff, Cherokee County; both in Alabama. Lingulella nathorsti Linnarsson. Plate XXXI, figures 1, la-h. lAngulella ? nathorsti Linnarsson, 1876, Bihang till K. svensk. Vet.-Akad. Handl., Bd. 3, No. 12, pp. 1.5-16, PI. Ill, figs. 24-30. (Described and discussed in English as a new species.) This is a medium-sized well-characterized species. As the illustrations of Linnarsson [1876, PI. Ill] are not altogether satisfactory I have had several drawings made from material received from Dr. G. Lindstrom. Plate XXXI, figures 1, la-b, represents specimens from the gray, arenaceous, slialy sand- stones at Andrarum, and Plate XXXI, figures Ic-e, specimens from the hard, dark-gray sand- stones in Dalarne. Specimens from the dark sandstone show the surface of the shell to have been marked by concentric striae and lines of growth and very fine radiating strisB. The casts from the arenaceous shales show the area of the valves (PI. XXXI, figs. 1 and lb) and traces of the vascular markings. Observations. — In form and outline Lingulella nathorsti may be compared with L. radula Matthew, but it differs greatly fi-om that species in its surface characters. The specific name was given in honor of Mr. A. G. Nathorst. Formation and locality. — lower Cambrian: (330x) In strata with Holniia kjerulfi at Andrarum, SO miles (32 Jem.) northwest of Simrishamn, Province of Christianstad; and (By) with Torellella ixvigata in the " Sparagmite " sandstone, at Skarosen, northwest Dalarne, Province of Kopparberg; both in Sweden. a 78 is the type locality. 522 CAMBRIAN BRACHIOPODA. LiNGULELLA NicHOLSONi Callawaj. Plate XXX, figures 3, 3a-f. Lingulella nicholsoni Callawat, 1874, Quart. Jour. Geol. Soc. London, vol. 30, p. 196. (JName proposed.) Lingulella nicholsoni Callaway, 1877, idem, vol. 33, pp. 668-669, PL XXIV, figs. 11, lla-b. (Described and discussed as below. Figs. 11 and lib are reproduced in this monograph, PL XXX, figs. 3 and 3a, respectively.) Lingxdclla nicholsoni Callaway, Davidson, 1883, British Fossil Brachiopoda, vol. 5, pt. 2, pp. 208-209, PL XVII, figs. 31, 31a, and 32. (The discussion of the species, the localities, and the figures given in the preceding reference are here copied.) Lingulella nicholsoni Callaway?, Matley, 1902, Quart. Jour. Geol. Soc. London, vol. 58, pt. 1, p. 141. (A new locality mentioned.) The original description by Callaway follows: Ovate, depressed, widest about the middle, two-thirds as broad as long, front and sides rounded, beak moderately acuminate, area of ventral valve striated, the strise parallel to the external slope of the valve, pedicle groove divided by a narrow ridge down the middle; visceral surface pitted; exterior surface marked by fine concentric lines of growth. Length, 5 lines; width, 3.5 lines. This is a larger shell than Lingulella ferruginea Salter and its sides are not so parallel. It closely resembles L. lepis (Salter) ; but L. lepis is wider toward the front, according to Davidson's figures [18S3, PI. XVII, figs. 31, 31a, and 32]. In a collection kindly lent to me by Dr. Charles Lapworth I found this species to vary greatly in outline in the shales. It is a well-marked species. Plate XXX, figures 3b and 3c, shows probably the most characteristic adult forms. The specific name was given in honor of Mr. Nicholson. FoKMATioN AND LOCALITY. — TTpper Cambrian: (3041 [Callaway, 1877, p. 669]) Shineton shales at Shineton, Mary Dingle, Dryton, Cressage, 1 mile (1.6 km.) west of Cressage, west of Earley, and under, Cound-Moor quarry; and (304k [Davidson, 1883, pp. 208 and 209]) Shineton shales at Bull Hill Cottage and Pewardine; all in South Shropshire, England. (3041) In the collection received from Dr. Charles Lapworth, collected by R. R. Rhodes, of the Geological Survey of Great Britain, the species is recorded in shales at the following localities: 2246, 2481, 2499, 2512, 2513, 2541, 2548, 2556, 2567, 2625, and 2627, all on Shineton Brook and vicinity. South Shropshire, England. (304a [Groom, 1902, p. 110]) "Bronsil shales; " and (304b [Groom, 1902, p. 109]) lower part of the "'WTiite Leaved Oak shales" (the zone of Polyphyma); both in the Malvern Hills, between Herefordshire and Worcestershire, England. Lingulella ora (Walcott). Plate XXXV, figures 9, 9a-d. Obolus (Lingulella) orus Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 330. (Characterized as below as a new- species.) This is a shell of the Lingulella manticula (White) form, but differs from it in being more elongate; ventral valve more acuminate and dorsal valve proportionately larger. Its nearest allies in form are among the group of narrow, elongate shells occurring in New Brunswick and Cape Breton. It differs from all of them — lAngulella collicia (Matthew), i. f/wmenis (Mat- thew), L. cama (Walcott), etc. — in having a thick, strong shell and usually more acuminate dorsal valve. The exterior surface bears rather strong concentric lines of growth and very fine, irregular, undulating, elevated strise that suggest the surface of Obolus (Westonia) ella (Hall and Whitfield) when seen in reflected light with a strong magnifier. This little shell occurs abundantly, but good interiors have not been found. The main vascular sinuses appear to be submargmal in both valves, and the visceral area of the dorsal valve narrow, extending a Uttle beyond the center of the valve. Formation and locality. — Tipper Cambrian: (9p) About 160 feet (48.8 m.) above the -porphyry contact in the limestones of the Reagan sandstone, in SE. \ NE. \ sec. 2, T. 4 N., R. 13 W.; and (9q) about 10 feet (3 m.) above the porphyry contact and 90 feet (27.4 m.) below the Arbuckle limestone, in limestones of the Reagan sandstone, in middle of west half of sec. 2, T. 4 N., R. 13 W.; both about 15 miles (24.2 km.) northwest of Fort Sill, Comanche County, Oklahoma. OBOLID^. 523 A single specimen of a ventral valve 4 mm. in length that is much like the corresponding valve of Lingulella ora occurs at the following locality. More and bettor material is needed before an identification can be made that is more than tentative. Middle Cambrian: (11m) Drill cores of limestone in the Bonneterre limertone at horizons 10 and 20 feet (3 and 6 m.) above the Lamotte sandstone at Flat River, St. Francois County, Missouri. Lingulella oweni (Walcott). Plate XVIII, figures 5, 5a-f. Obolus {Lingulella) oiveni Walcott, 1898, Proc. U. S. Nat. Mus., vol. 21, p. 410. (Described and discussed essentially as below as a new species.) General form ovate, with the ventral valve obtusely acuminate, and the dorsal valve more broadly rounded posteriorly; valves appear to have been moderately convex, as far as can be determined from the flattened specimen in the shaly sandstones. Surface of shell marked by concentric lines and stri» of growth and indistinct, radiating striae. There are no traces of the interior markings observed. The shell is of medium thickness; none of the specimens show how it was built up, farther than that there were obHque lamellae attached to the outer layer in the anterior portion of the valve. The largest ventral valve from Gibraltar Bluff has a length of 16.5 mm.; width, about 12 mm.; an associated dorsal valve 14 mm. in length, has a width of 11 mm. as it occurs flattened on the surface of the sandstone. A smaller shell referred to this species from Osceola averages from 6 to 8 mm. in length. As shown in the cast of an interior of a shell, the area is rather long, and divided midway by a sharp pedicle furrow; the flexure hnes are situated about midway between the cast of the pedicle furrow and the lateral margin. The area formed a thin shelf between the pedicle groove and the lateral margins, the undercut extending far back under the area; a broken portion of this is preserved on the cast illustrated by figure 5a. One cast of the interior of a ventral valve shows a slight trace of the visceral area (PI. XVIII, fig. 5d). In a cast of a dorsal valve (fig. 5b) both the central and anterior lateral muscle scars are somewhat indistinctly preserved. Observations. — This species is most nearly related to Lingulella ampla (Owen). It differs, as far as can be determined from the material for comparison, in being less elongate and in the position of the central and anterior lateral muscle scars in the dorsal valve, as may be seen by comparing Plate XVIII, figure 5b, with Plate XXVIII, figure Ig. The typical form of this species is represented on Plate XVIII, figures 5, 5b, and 5c, and a smaller form, which has been referred to it, by figures 5d, 5e, and 5f. The species differs strongly from Oholus ( Westonia) stoneanus (Whitfield) in its surface markings, although the outline of the valves is almost the same in the two species. The specific name was given in honor of Dr. D. D. Owen. Formation and LOCALrry. — TTpper Cambrian: (78c) "St. Croix sandstone" at Osceola, Polk County; (86) "St. Croix sandstone" at Van Ness's quarry, Gibraltar Bluff, Lodi, Columbia County; (85z) "St. Croix sandstone" at Madison, Dane County; (85a) "St. Croix sandstone" at Brown's quarry, Prairie du Sac, Sauk County; and (85s) "St. CroLx sandstone" at Prairie du Sac, Sauk County; all in Wisconsin. (97) "St. Croix sandstone" at Reads Landing, foot of Lake Pepin, Wabasha County, Minnesota. Lingulella peeattenuata (Whitfield). Plate XXI, figures 1, la-i. Lingulepis perattenuatus Whitfield, 1877, U. S. Geog. and Geol. Survey Rocky Mtn. Region, Rept. Geol. Black Hills of Dakota, Prelim. Rept., p. 9. (Described and discussed as on p. 524 as a new species.) Lingulepis perattenuatus Whitfield, 1880, U. S. Geog. and Geol. Survey Rocky Mtn. Region, Rept. Geol. and Re- sources Black Hills of Dakota, by Newton and Jenney, p. 337, PI. II, figs. 7-9. (Copy of preceding refer- ence. The specimens represented by figures 7, 8, and 9 are redrawn in this monograph, PI. XXI, figs, li, Ih, and lb, respectively.) 524 aOIBRIAN BRACHIOPODA. Linffitlepis cuneohis Schtchert (in part) [not Whitfield], 1S97, Bull. U. S. Geol. Survey No. 87, p. 259. (Merely refers Whitfield's Lingukpis pcratteniiatus to L. cuneolus.) Obolus (Lingulella) pcrattenuatus (^liitfield), Walcott, 1899, Mon. U. S. Geol. Survey, vol. 32, pt. 2, p. 443. (Merely changes generic reference.) The original description by TTliitfield follows : Shell spatula te or elongate-ovate, becoming acutely pointed toward the beak; sides below the middle of the length of the ventral valve rounded; front margin very regularly curved; cardinal slopes straight, or sometimes slightly convex; greatest width a little more than half the length of the ventral valve and sometimes nearly two-thirds as great. Surface of the ventral valve depressed convex, very slightly subangular along the middle above the lower third of the length, and a little more distinctly so in the upper part. Apex scarcely truncate. Dorsal valve considerably shorter than the ventral, broadly truncated at the upper end, the line of truncation being distinctly arched. Surface evenly convex. Structure of the surface of the shell polished, with fine, somewhat lamellose lines of growth. The material studied by WTiitfield, now in the collections of the United States National Museum, has been carefully worked over and the cardinal area of both valves developed in the casts of the interior of the shell (PI. XXI, figs. 1 and Id). The plane of the area of the ventral valve coincides near its edges "\\"ith the edge of the shell, but it rises quite rapidly toward the pedicle furrow. It is divided at the center by a rather deep, strongly marked pedicle furrow and near the lateral margin b}' a rather sharp, very narrow flexure line (PI. XXI, figs, la and Ic). The strife of growth cross the area parallel with its base. They are sharp and crowded on the lateral slopes, but are very indistinctly preserved in the pedicle groove. The area of the dorsal valve is lower than that of the ventral and, in the typical specimens, shows nothing more than the fine strise of growth (PL XXI, fig. li). No traces of muscle scars or vascular markings have been found in the material from the type locality in the Black Hills, but, in some casts of the interiors of valves from Texas, traces of the visceral cavit}" and muscle scars are sho^vn. In Plate XXI, figure le, the outline of the visceral cavity (v) is preserved, also the main vascular sinus (vs). Both valves of the shell are much thinner than in Lingulella acutangula (Roemer). The shell is formed of a thin outer layer and one or two inner layers or lamellae, which occur in the posterior haK of the shell. The surface of the outer layer is marked by concentric strife and lines of growth and very fine, more or less interrupted radiating striae. The inner layer is characterized on its outer surface by fine, concentric, radiating strife. A few minute punctae occur on the inner surface of several shells, as shown by the papillse on the cast. Oiservations. — The most nearly related species in the American Cambrian rocks is L. acutangula (Roemer). It differs in having a much tliinner shell, and, as far as they are pre- served, in the character and position of the interior markings and muscle scars. The type species was described from the "Potsdam formation" of the Black Hills. From a recent study of the Black Hills Cambrian section I have found that it is from the ^liddle Cambrian sandstones and limestones as they occur near the headwaters of Red Canyon Creek and in the vicinity of Deadwood. It is also identified from the Middle Cambrian of central Texas and in the same fauna from the "Tonto" sandstone of the Grand Canyon of the Colorado, Arizona. In the Black Hdls it is associated with Lingulella (Lingulepis)' acunfiinafa (Conrad) and Dicellomus politus (Hall) . Formation axd locality. — Tipper Cambrian: (67c) Sandstone on Tatur HOI, 7 miles (11.2 km.) northwest of Bumet, Burnet Coimty; i70j limestone near Morgans Creek, Burnet County; and (68y) interbedded sandstone and limestone on Packsaddle Mountain, Llano County; all in Texas. Middle Cambrian: (355) Sandstones on Red Canyon Creel:, southwest side of Black Hills; and (355f) sandstones near Deadwood, Black HUls; both in South Dakota. (74) Sandstone about 300 feet (91.4 m.) above the base of the Tonto group, at the head of Nunkoweap Valley; and (74d) sandstone beds in the "Tonto'' shale just above massive sandstones near the mouth of Bass Canyon, on the south side of the Grand Canyon of the Colorado, southeast of Powells Plateau; both in the Grand Canyon of the Colo- rado, Arizona. A single ventral valve of this species, or a closely related form, occurs in the follo^ving locaUty: Middle Cambrian: (9o) Siliceous limestone about 15 feet (4.6 m.) above the Coronado quartzite [Lindgren, 1905, p. 3], 0.5 mile (0.8 km. j southwest of Milk ranch, on the first spur north of the one which the main road follows, Clifton quadrangle (U. S. Geol. Sur\-ey,i, Graham County, Arizona. OBOLID^. 525 LlNGULELLA PHAOJf (Walcott). Plate XXVI, figures 1, la-e. Obolus (Lingulella) phaon Walcott, 1S98, Proc. TJ. S. Xat. Mus., vol. 21, pp. 410-411. (Described and discussed essentially as below as a new species.) General form ovate, M'iih the ventral valve subacuminate, and the dorsal broadly ovate; valves of moderate convexity. Surface of the shell marked by fine concentric lines and strise of growth, and very fine more or less interrupted radiating strise; when the outer laj^er is exfo- liated the inner surface is marked hj numerous fine radiating strife; the interior surface as seen in casts is more or less marked hy rather large papillse arranged in concentric lines, the papillgs corresponding to the pits or punctie on the inner surface of the shell. The shell is rather thick, and is built up of a thin outer layer and several inner layers or lamellae, the lamellae toward the front being obUque to the outer layer. A large ventral valve 1 5 mm. in length has a width of 13 mm.; a dorsal valve 11 mm. long has a width of 10 mm. As sho\\Ta in the cast of the interior of the shell, the area of the ventral valve rises gradu- ally from the margin toward the pedicle groove. It is broken midway by the cast of a strong pedicle furrow and a Httle more than halfway up toward the lateral margin by a strong flexure line; the strise of growth are very fine and cross the area parallel with its base. The cast of the undercut shows that the area formed a thin shelf between the pedicle groove and the lateral margins. The area of the dorsal valve is well defined. As in the ventral valve the area formed a thin shelf, as sho\\Ti by the cast of the undercut extending weU over the area in several of the specimens; the cast of the broken edges of the undercut between the areas is shoAvn by Plate XXVI, figures lb, Ic, Id. The cast of the interior of the ventral valve (PI. XXVI, figs, lb and Ic) shows the strongly defined, narrow, visceral area (v), the trapezoidal area (c) in which the central, middle, and outside lateral muscle scars occur, also the anterior lateral muscle scars (j), and unusuaUy strong main vascular sinuses (vs). In a specimen which is not illustrated, apparent lines of growth occur on the ridge in front of the trapezoidal area (c), a feature that is present in L. Jiayesi (Walcott) and Oholus matinalis (Hall). In a dorsal valve the relatively narrow central vascular area extends forward nearly to the center of the shell (PL XXVI, fig. Id); central (li) and anterior lateral (j) scars are faintly indicated, also transmedian (i) scars, and the median septum (s); the main vascular sinuses (vs) are unusuaU}- deep and well defined. Ohservations. — Tliis species at first inspection might be taken for Lingulella ampla (Owen) (PI. XXVIII). It occurs at the same horizon in association with Dicellomus 'politus (Hall). It differs in having a broader and less elongate shell, with the visceral area- of the dorsal valve terminating near the center instead of forward of the center, and, as far as can be deter- mined from the material at hand, in having a thicker shell. It also averages about one-fourth less in size. Formation and locality. — Upper Cambrian: (98 and 98x)a "St. Croix sandstone" near Eau Claire, Eau Claire County; and (83a) "St. Croix sandstone" 25 feet (7.6 m.) above the water level near the Knapp, Stout and Company's buildings, Menomonie, Dunn County; both in Wisconsin. (84a) "St. Croix sandstone " at River Junction, Houston County, 20 miles (32.2 km.) below Dresbach, Minnesota. Lingulella pogonipensis (Walcott). Plate XX. figures 3, 3a-c. Oholus {Lingulella) pogonipensis Walcott, 1898, Proc. U. S. Nat. Mus., vol. 21, pp. 411—112. (Described and dis- cussed as below as a new species.) Shell rather large, general form ovate, almost ovate cuneate in the ventral valve: dorsal valve more ovate. Valves moderately convex. Surface of the shell marked by numerous concentric lines and strise of growth, and very fine radiating strise; the finer concentric strise are shghtly irregular, but not nearly so much so as in many species of the genus. The outer a 98x is the type locality. 526 CMIBRIAN BRACTIIOPODA. surface of the inner layer is marked by very fine radiating strige, also concentric lines of growth. The shell is below the average thickness and is formed of a thin outer layer, and one or more inner layers or lamellae. The largest ventral valve has a length of 15 mm.; width, 11 mm. As shown by a partial cast the area is of medium length, and divided midway by a narrow, strongly marked cast of the pedicle furrow. Observations. — In form the valves of this species somewhat resemble those of Lingulella ampZa. (Owen) (PI. XXVIII), and more closely those of L. isse (Walcott) (PI. XXXIX). In the absence of all interior markings no further comparisons can be made. The species derives its specific name from its occurrence in the Pogonip limestone. Formation and locality. — Passage beds between the Upper Cambrian and the Ordovician: (201) Arenaceous Pogonip limestone, on east slope of ridge east of Hamburg Ridge; (205) siliceous limestone on Roundtop Mountain; (203a) limestones at base of Pogonip limestone, in the spur on Hamburg Ridge extending out southwest from Wood Cone; and (211) siliceous Pogonip limestone, on spur of Hamburg Ridge extending southwest from Wood Cone; all in the Evu-eka district [Hague, 1892, Atlas], Eureka County, Nevada. Specimens somewhat doubtfully referred to this species occur at the following localities: Tipper Cambrian : (32f ) Thin-bedded siliceous limestones near the top of the Upper Cambrian, about 2 miles (3.2 km.) southeast of Muskrat Spring, on the northwest face of Grantsville Peak, Stansbury Range, Tooele County, Utah. Upper? Cambrian: (358a) Siliceous limestone in Pinal County, Arizona. Lingulella prima (Conrad MS.) (Hall). Plate XXVII, figui-es 1, la-c. ' Lingula ovata Emmons [not McCoy], 1842, Nat. Hist. New York, Geology, pt. 2, p. 105. (Mentioned.) lAngula prima (Conrad MS.) Hall, 1847, Nat. Hist. New York, Paleontology, vol. 1, p. 3, PL I, fig. 2. (Described and discussed. It is the first description of the fossil, though no reference is made to the fact that it is a new species.) ' ; Lingula prima Hall, Emmons, 1855, American Geology, vol. 1, pt. 2, p. 202. (Described.) Lingulepis prima (Hall), Miller, 1877, American Paleozoic Fossils, Catalogue, p. 115. (Merely changes generic reference.) Obolella prima (Hall), Whitfield, 1884, Bull. Am. Mus. Nat. Hist., vol. 1, No. 5, pp. 142-143, PI. XIV, figs. 3-5. (Discussed.) Lingulella f prima (Hall), Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, p. 69, footnote. (Discussed.) Lingulepis prima (Hall), Schuchert (in part), 1897, Bull. U. S. Geol. Survey No. 87, p. 260. (Merely changes generic reference. Includes species other than Hall's ''Lingula prima") Obolm (Lingulepis) primus (Hall), Walcott, 1901, Proc. U. S. Nat. Mus., vol. 23, p. 673. (Merely changes generic reference.) General form subovate with the ventral valve subacuminate and the dorsal valve broadly subacuminate. There is a tendency in some individuals to a subcuneate outline. Valves moderately convex, increasing in some shells to almost strongly convex. There is some range of variation in the outlines of the valves, as shown by Plate XXVII, figures 1 and la. The surface of the shell is marked by concentric lines and small undulations of growth and by very fine radiating strise. When the outer layer is exfoliated the inner layer is seen to be marked by sharp radiating strise and a few concentric lines of growth. The interior surface shows fine radiating strise and a few scattered pits. The shell is of medium thickness and formed of a thin outer layer and several inner layers, or lamellse, which are more or less oblique to the outer layer; the lamellse are much more numerous toward the margins and form a rather thick rim around the anterior and anterolateral margins. The average length of the ventral valve is 5 mm., width 4 mm. The dorsal valve is slightly shorter in proportion to its width. As shown in the interior casts the area of the ventral valve is relatively short; it is divided at the center by a rather strongly marked pedicle furrow and well out toward its margins by clearly defined flexure lines. Faint traces of strise of growth cross the area parallel with its base; the area of the dorsal is not shown in any of the specimens in the collection. The cast of the interior of the ventral valve shows the visceral cavity (v), the trapezoidal area (c), and the rather strong median ridge, which extends from the area forward to the anterior OBOLID.E. ,^ 527 margin of the visceral area. This ridge corresponds to a median groove passing anteriorly into the heart-shaped cavity. There are no clearly defined muscle scars in any specimen in the collection, although the trapezoidal area in the ventral valve, in which the central, middle, and outside lateral muscle scars usually occur, is fairly well preserved in one specimen. None of the casts of the dorsal valve show more than the cast of the median ridge or septum. Of the markings left on the shell by the vascular system only the main vascular sinuses have been preserved on the cast of the ventral valve. Observations. — This is a small but striking species that occurs in the sandstones east of the Adirondack Mountains. In outline and form it may be grouped with Lingulella ferruginea Salter and L. hellula (Walcott) (PL XIX). It is a larger and more acuminate shell than L. ferruginea, and its dorsal valve is distinguished from that of L. hellula by being shorter and broader anteriorly. It occurs quite abundantly in the thin beds of hard sandstones at Ausable Chasm, below Keeseville, Essex County, New York, associated with Ptychoparia minuta and L. (Lingulepis) acuminata (Conrad) ( ?)• The interior of the ventral valve resembles typical forms of Oholus more nearly than the typical forms of Lingulella. This may be due to the state 01 preservation or it may be that, despite the Lingula-\ike outlines of the valves, it is more a true Oholus in its interior markings as these are developed in 0. matinalis (Hall). (Compare PI. VIII, fig. le, with PI. XXVII, fig. 1.) Whitfield [1884, p. 142] referred the species to the genus Oholella. There is a strong resemblance between the dorsal valve of the species and that of some of the species of Oholella, but a careful study of a large amount of material shows that this resemblance is confined to the dorsal valve. He also refers "Oholella nitida" Ford to tliis species, but "0. nitida" is a true Acrotreta and occurs in the lower portion of the Olenellus fauna of the Lower Cambrian, amd Lingulella prima (Hall) is from the Upper Cambrian. ' ' Dwight [1886, p. 208] mentions "Oholella (Lingulella) prima" as occurring in "Potsdam" strata at Poughkeepsie, New York, but inasmuch as he does not describe the specimen, and the form has not been found in other extensive collections that have been made there, the reference is considered as exceedingly doubtful. I think Dwight had small specimens of the dorsal valve of Lingulella (Lingulepis) acuminata (Conrad), which occurs at the locality at Poughkeepsie. Formation and locality. — ITpper Cambrian : (77) " Sandstone, near the water below the falls at the high bridge, and also at several horizons in the section, the highest point being 70 to 7.5 feet {21 to 23 m.) above the water, in Ausable Chasm; (367f) sandstone at French Creek, 1 mile (1.6 km.) east of Keeseville; (367g) sandstone in the bed of the brook, in the suburbs of Port Henry; (367h) Rosses Bridge, 4 miles (6.4 km.) west of Essex; (136) Potsdam sandstone in bank of stream opposite the first switch on the Port Henry and Maine Railroad out of Port Henry; and (338t^ Potsdam sandstone in Ausable Chasm, below Keeseville; all in Essex County, New York. Lingulella? priisleva Hicks. Plate XXXI, figures 5, 5a. « Lingulella primxva Hicks, 1871, Quart. Jour. Geol. Soc. London, vol. 27, p. 401, PI. XV, figs. 13 and 14. (Deacribed as a new species.) Lingulella primieva Hicks, Salter and Etheridge, 1881, Mem. Geol. Survey Great Britain, vol. 3, 2d ed., p. 538. (Localities mentioned.) Lingulella primxva Hicks, 1881, Popular Science Review, new ser., vol. 5, p. 297. (Mentioned only.) Lingulella primxva Hicks, Davidson, 1883, British Fossil Brachiopoda, vol. 5, pt. 2, p. 208, PL XVII, figs. 33 and 34. (Described and discussed. Fig. 33 is drawn from the specimen figured by Hicks, 1871, PL XV, fig. 14. Figs. 33 and 34 are reproduced in this monograph, PL XXXI, figs. 5a and 5, respectively.) This species is rather doubtful, owing to its condition of preservation, which renders it quite difficult to make any comparison with other described species. It occurs in association with L. ferruginea Salter, but is a much larger species. Formation and locality. — Middle? Cambrian: (366c) "Caerfai group" [Salter and Etheridge, 1881, p. 5381 "-t Caerfai, Nuns Hill, and Porthclais Harbor, all south of St. Davids; and (318i) red shales of the Caerfai group at St. Davids; both in South Wales. a 77 is the type locality, though the specimens in the United States National Museum collections to which that number is assigned were collected later than the type specimens. 528 CAMBRIAN BEACHIOPODA. LlNGTILELLA PUNCTATA (Walcott). Plate XX, figures 6, 6a. Lingula? manticula Walcott [not White], 1884, Mon. U. S. Geol. Survey, vol. 8, pp. ici-l4, PI. IX, fig. 3, and PI. XI, fig. 2. (Discussed. The specimens represented by PL IX, fig. 3, and PI. XI, fig. 2, are redrawn in this monograph, PI. XX, figs. 6 and 6a, respectively.) Obolus {Lingulella) punctatus Walcott, 1898, Proc. U. S. Nat. Mus., vol. 21, pp. 412-413. (Described as below as a new species.) General form ovate, with the ventral valve subacuminate. Valves moderately convex, with the dorsal valve having a slightly depressed median sinus that extends from near the umbo to the anterior margin. Surface of shell marked by lines and striie of growth, and very fine, slightly tmdulating strise; also a few faintly indicated radiating striae; when the outer layer is exfoliated the outer surface of the inner layer is seen to be marked by numerous and very fine radiating striae, in addition to the concentric lines of growth; the interior of the shell, as shown by the casts, was strongly pitted or punctate, the punctse being arranged in concentric lines following the lines of growth. The shell is relatively thin and formed of a thin outer layer a,nd one or more thin inner layers or lamellae. The type specimen of the ventral valve has a length of 9 mm., width 6.5 mm. An asso- ciated dorsal valve has a length of 7 mm., width 5.5 mm. The only interior that shows anything more than the punctate surface is that of the dorsal valve. In this the area is partly shown; it is relatively short and marked by fine striae par- allel to its base, and two imperfectly developed flexure lines. The cast of a narrow median septum is well shown, and on each side of it the middle lateral muscle scars. The path of advance of the central muscle scars is quite plain, also one of the scars. The only trace of the vascular system is a portion of a main vascular sinus. This form owes its specific name to the concentrically punctate interior of the shell. Formation and locality. — Upper Cambrian: (8i) Limestone at summit of canyon, 10 miles (16.1 km.) south of Bgan Canyon, east side of Egan Range, \^Tiite Pine County; (8o) limestone on the slope of the ridge where the range swings around to the northwest, 2 miles (3.2 km.) north of Aurum, Schell Creek Range, White Pine County; (61) limestone in the Dunderberg shale [Walcott, 19081, p. 184], a little south of the Llamburg mine. Eureka district [Hague, 1892, Atlas], Eureka County; and (63) limestone in the Dunderberg shale [Walcott, 19081, p. 184], in canyon immediately north of Adams Hill, Eureka district [Hague, 1892, Atlas], Eureka County; all in Nevada. Middle Cambrian: (7i) Limestone just west of the summit on the road east of Schellbourne, Schell Creek Range, White Pine County, Nevada. (54) Eldorado limestone [Walcott, 19081, p. 184], on east slope of Prospect Mountain, in New York Canyon; (57) shaly limestone in the Eldorado limestone [Walcott, 1908f, p. 184], at the 700-foot (213.4 m.) level in the Rich- mond mine. Ruby Hill [Hague, 1892, p. 43, and PL I, opposite p. 116]; and (58) shaly limestone in upper beds of Secret Canyon shale, east side of New York and Secret canyons; all in the Eureka district [Hague, 1892, Atlas], Eiu'eka County, Nevada. LiNGULELLA QUADRILATERALIS (Walcott). Plate XXXIX, figiu-es 6, 6a. Obolus (Lingulella) quadrilateralis Walcott, 1905, Proc. U. S. Nat. Mm;., vol. 28, p. 331. (Described and discussed as below as a new species.) General form rounded, quadrilateral; valves moderately convex. Surface marked by con- centric lines and ridges of growth with fine striae between. The surface of the inner layers of the shell is shiny and marked by fine radiating strias in addition to the concentric lines. The shell is rather thin; it is built up of several layers. Ohservations. — This species differs from other described species by its subquadrilateral outline. In this respect it may be compared with Obolus ( Westonia) chuarensis (Walcott) (PL XXV), from which it differs in having a thinner shell and different surface markings. Formation and locality. — Middle Cambrian: (91) Conasauga {"Coosa") shale, at Cedar Bluff, Cherokee County; and (56q) limestone at the very top of the Conasauga limestone, in quarry at Ketona, about 5 miles (8 km.) northeast of Birmingham, Jefferson County; both in Alabama. (140a) Shales 200 yards (182.9 m.) east of Thomas Mills, 5 miles (8 km.) north of Cave Spring, Floyd County, Georgia. OBOLID^. 529 LiNGULELLA RADtlLA MattlieW. Plate XLV, figures 1, la-1. Lingulella radula Matthew, 1891, Trans. Roy. Soc. Canada, 1st ser., vol. 8, sec. 4, ISlo. ti, pp. 147-148, PL XV, figs. 7a-b and 8a-e. (Described and discussed as a new species. PL XLV, figs. 1, la, lb, Ic, and le, are drawn from specimens in Matthew's type material, but fiu-ther identification is impossible.) Lingulella radula aspera Matthew, 1903, Geol. Survey Canada, Kept. Cambrian Rocks Cape Breton, pp. 204-205, PL XV, figs. 2a-d. (Described and discussed as a new variety.) General form ovate cuneate, with the ventral valve subacuminate and the dorsal valve broadly OA^ate in outline; valves apparently moderately convex, but tliis is uncertain, as the shells have all been compressed in the arenaceous shale. Surface marked by concentric lines of growth and very fine, irregular strise. It is the type of surface of Oholus ( Westonia) ella (Hall and Wliitfield) or Lingulella {Lingulepis) gregwa (Matthew), reduced so that the surface, under a strong magnifier, has a roughened or minutely papUlose appearance. Matthew [1891, p. 148] describes it as due to wavy squamose ridgelets having the edges and points directed forward, as in Botsjordia pulchra (Matthew). 0\ving to this roughened surface the outer layer of the shell usually adheres to the matrix, leaving the dark, shiny surface of the inner layer. The inner surface is marked by concentric rows of pimctse and fine radiating strise. The shell is of medium thickness and formed of a tliin outer layer and several inner layers or lamellae, which are more or less oblique to the outer layer on the anterior half of the shell, One of the largest ventral valves has a length of 10 mm., width 8 mm.; a large dorsal valve has a length of 9 mm., width 8 mm. The cardinal area and pedicle groove are usually obscured by the adhering fragments of shell. The pedicle groove is strong and narrows gradually as it crosses the long area of the ventral valve. The area of the dorsal valve is short and broad. The cast of the visceral cavity (v) is preserved in a number of specimens. In Plate XLV, figures 1 and li, the heart-shaped pit (x), so characteristic of Oholus and of Lingulella acutangula (Roemer), is clearly outlined. A narrow median septum (s) is found in the dorsal valve (PL XLV, figs. Ij and 11), and the anterior lateral muscle scars (j, fig. li) are clearly shown in the ventral valve. The centrals, middle laterals, and outside laterals can not be cUfferentiated in the trapezoidal area (c) in front of the heart-shaped pit. On the dorsal valve the centrals (h, figs. Id, Ij, and ll) and anterior laterals (j, fig. Ij) are finely preserved. Considerable portions of the markings of the vascular system are preserved on the casts of the interior of the valves. The main vascular trunks of the ventral valve are shown by figures 1, la, and Ic, and the position of the parietal scar is also seen at ps (figs, la, Ic, and li). Observations. — Doctor Matthew sent me the types of this species for study and illustration. 1 have not been able to interpret some of the interior markings in the manner that his figures indicate, but this is not unexpected when the obscure character of most of the specimens is considered. Wlien at St. John, in 1877, 1 collected a large number of specimens of this species, and, as they are somewhat better preserved than the types, drawings have been made of the casts of the interiors of three ventral valves and one dorsal valve. The variety, spoken of by Matthew [1903, p. 204], from the lower portion of Division 2c shows the outer surface unusually well preserved, but I do not think it is a distinct species or worthy of a varietal name. In the collections made by LojDer on McPhees Brook, Division 2 of Matthew's section, there are small specimens that correspond to Matthew's variety aspera collected on McNeil Brook; also adult specimens. The horizon is much lower, according to Matthew's sections, but the specimens are very much alike from the two localities. Formation and locality. — Middle Cambrian : (301y) Shaly sandstones of Division C2c of Matthew, east side of Courtney Bay, St. John; and (301x) sandstones of Division C'2c of Matthew, in the city of St. John; both [Matthew, 1891, p. 148] in New Brunswick. (307c [Matthew, 1903, p. 205]) Sandstones probably belonging with Division C2c of Matthew, on Mira Riverj and (307b) sandstone on McPhees Brook; both in eastern Cape Breton, Nova Scotia, Canada. 62667°— VOL 51, pt 1—12 34 530 CMIBRIAN BRACHIOPODA. LiNGULELLA EANDOMENSIS (Walcott). Plate XXI, figures 5, 5a. Oboliis {LinguMla) randomensh Walcott, 1901, Proc. U. S. Nat. Mus., vol. 23, pp. 688-689. (Described and discussed as below as a new species.) General form elongate ovate; ventral valve rather broadly subacuminate, and the dorsal valve slightly acunrinate. The widest portion of the valves is the anterior tliird, from which they very gradually narrow toward the cardinal slopes. The convexity of the valves is mod- erate and uniform and nearly the same in each. Surface of the shell marked by fine concentric striae, and rather strong lines of growth, also fine radiating strias. The shell is formed of a few thin lamellae or layers, as far as can be determined from the fragments preserved on the casts in the sandstone. The longest ventral valve in tlie collection has a length of 10 mm. with a maximum width of 6 mm. The dorsal valve is slightly shorter. As shown by the interior cast the area of the ventral valve is rather long, and extends well forward on the cardinal slopes. It is divided at the center by a narrow pedicle furrow and midway by a very slight flexure Une. The base of the area curves backward over the margin, arching slightly forward before reaching a rather deep indentation at the center. The stride of growth cross the area parallel to its base. They are very sharp and fine and quite uniformly distributed over the area. Area of the dorsal valve unknown. Oiservations. — This pretty species occurs in great numbers in thin layers of brown sand- stone embedded in a dark shale a short distance below the Olenus zone. In form it resembles LinguMla mosia osceola (Walcott) (PI. XVIII, figs. 2 and 2c). It differs from it in having a narrower pedicle furrow and, when comparing a large number of specimens, in being slightly more elongate. It is proportionately narrower toward the beak. The species derives its specific name from its occurrence on Random Island. Formation and locality. — Tipper Cambrian: (6y) Sandstone on north side of Random Island, between Birch and Sandy points, Smith Sound, Trinity Bay, Newfoundland. LiNGULELLA ROTUNDA (Mattliew). Plate XXXVII, figures 3h-k. Lingulepis rotunda Matthew, 1903, Geol. Survey Canada, Kept. Cambrian Rocks Cape Breton, p. 199, PI. XIV, figs. 4a^f. (Described and discussed as a new species.) This small species is marked by its nearly circular, convex dorsal valve. The inner surface of the shell is strongly punctate, but I could not find the minute tubercles on the outer surface of the dorsal valve described by Matthew. The outer surface, where preserved, appears to be smooth or marked by concentric striae. Formation and locality.— Middle Cambrian: (325a [Matthew, 1903, p. 199]) Shales of Division C2c of Matthew's [1903, p. 49] Bretontan, on the eastern slope of the valley of McNeil Brool, on the road to Trout Brook, in the Mira JRiver valley; (31) in compact, fine-grained, thin-bedded, gray sandstone, of the Paradoxides zone, on McLean Brook, 1 mile (1.6 km.) east of McCodrum Brook, and 1.5 miles (2.4 km.) west of Marion Bridge; and (325c) sandstone on the shore of Bras d'Or Lake; all in eastern Cape Breton, Nova Scotia, Canada. LiNGULELLA SCHUCHERTI (Walcott). Plate XXI, figure 6. Obolus (Lingulella) schucherti Walcott, 1901, Proc. U. S. Nat. Mus., vol. 23, pp. 689-690. (Described and discussed as below as a new species.) General form elongate ovate, ventral valve subacuminate and the dorsal valve elongate ovate in outline. Surface marked by fine concentric stria?, and rather strong concentric undu- lations or lines of growth ; also line radiating striae, and on some specimens indistinct, radiating, rather narrow, depressed furrows. OBOLID.E. 531 The outer surface of the inner layers shows radiatmg strife and concentric lines of growth. The~radiating striae are also present on the inner surface outside of the area of the vascular cavity. The shell is tliick and foi-med of a thin outer layer and several thin inner laj^ers or lamellae arranged very much as in other shells of the genus Lingulella. The largest ventral valve has a length of about 11 mm.; vddth, 7 mm. A dorsal valve 8 mm. in length has a width of 5.5 mm. Casts of the interior of the ventral valve show a well-marked area, with a broad, strong pedicle furrow. The base of the area arches strongly forward. Just at the center, across the pedicle furrow, however, it has a slight backward arch. None of the specimens show the flexure line or the extent of the area along the cardinal slopes of the valve. The area of the dorsal valve is unknown. None of the characters of the visceral cavity or vascular markings are shown with sufhcient clearness to describe them. A tubercle on each side of the median line, just in advance of the area, indicates the main vascular sinus, and a depression the position of the anterior portion of the visceral cavity. Observations. — This is probably the oldest species of the genus Lingulella. It is associated with Botsfordia cselata (Hall), EUiptocepliala asa-phoides Emmons, and other characteristic species of the Lower Cambrian. In its elongate dorsal valve it recalls Oholus rhea Walcott of the Middle Cambrian (PI. IX, figs. 1, la-c). It differs from that species in the character of the shell and the outline of the valve. The specific name is given in honor of Prof. Charles Schuchert, who collected the onlj^ speci- men of the species known to me. Formation and locality. — lower Cambrian; (367) Conglomerate and limestone, Troy, Rensselaer County, New York. Lingulella siemiradzkii (Walcott). Plate XXXI, figures 2, 2a. Lingula ap. cf. exunguis Eichwald, Sibmiradzki, 1886, Jahrb. K.-k. geol. Reichsanstalt for 1886, Bd. 36, Hft. 4, p. 672. (Mentioned in German.) Lingula cf. exunguis Eichwald, GtJRicH, 1892, Neues Jahrb. fur Mineralogie, Bd. 1, p. 69. (Mentioned in German.) Lingula sp. Lingula aff. exungui Eichwald, GiJRicH, 1896, Verhandl. Russ.-kais. min. Gesell. St. Petersburg, 2d ser., Bd. 32, p. 214. (Discussed.) Oholus {Lingulella) siemiradzhii Walcott, 1901, Proc. U. S. Nat. Mus., vol. 23, pp. 690-691. (Discussed as below . as a new species.) Attention was called to this species by Siemiradzki [1886, p. 672] in connection with his study of the Paleozoic rocks of the Mittelgebirge of Poland. He speaks of it as "Lingula sp." in the black conglomerate, and compares it with " L. exunguis Eichwald." In the associated gray sandstone he found an Oholus which he says is identical with "0: siluricus Eichwald." Gixrich discusses the Cambrian of Sandomierz in a paper on the Paleozoic of the Mittel- gebirge, and mentions [1896, p. 17] Siemiradzki's discovery of fossils in the lower sandstones and shales. Gurich added greatly to the fauna found by Doctor Siemiradzki. He mentions [1896, p. 17] Paradoxides cf. tessini, P. hohemicus, Agnostus fallax, A. gihhus, and Liostracus linnars- soni, and refers the famia to the Middle Cambrian. The "Lingula" he compares [1896, p. 214] with "Lingula crassa Eichwald," calling attention to the resemblance in the siu^ace charac- ters; also to those of Lingulella davisi (McCoy). This is a small shell belonging to the group of species containing Lingulella ferruginea Salter, L. desiderata (Walcott), etc. The outer surface is marked by concentric, slightly undu- lating, and imbricating striae of growth, and the outer surface of the inner layers by fine radiat- ing striae. The general form and other characters are represented in Plate XXXI, figures 2 and 2a. Through the kindness of Dr. Fr. Schmidt I received a fi-agment of gray quartzitic sand- stone containing a large number of specimens of the "Lingula" of Siemiradzki. The shell 532 CAMBRIAN BRACHIOPODA. proves to be a true Lingulella. In the same piece of rock an obscure form of Oholus occurs that may be a medium-sized Oholus apoUinis Eichvvald. I take pleasure in naming the Lin- gulella after its discoverer, Dr. J. S. Siemiradzki. Formation and locality. — Middle Cambrian: (368) Quartzitic sandstone in the Pepper Mountains, near Sandomierz, on the Vistula, Russian Poland. Lingulella ? signata (Barrande). Plate XXX, figure 11. Lingula ? signata Barrande, 1868, Faune silurienne des environs de Hof, en Baviere, p. 103, fig. 73. (Described and discussed in French as a new species. Fig. 73 is reproduced in this monograph. Pi. XXX, fig. 11.) Lingula ? signata Barrande, 1868, Neues Jahrb. fiir Mineralogie for 1868, p. 692, unnumbered plate, fig. 73. (Copy of preceding reference.) This species is doubtfully referred to Lingula by its author. It is oval in outhne, with a strongly arched sm"face. Where the shell is partly removed two small, elongate impres- sions are seen near what is supposed to be the posterior portion of the valve, and on the front portion of the shell a longitudinal groove. Barrande [lS68a, p. 103] remarks that the latter recalls the perforation of Discina; but it is not perforated, as the shell continues over the entire surface of the depression. The aspect of the shell is horny and without ornamentation. Length, 2.5 mm.; wddth, 2 mm. It is verj^ doubtful if this species should be referred to Lingulella, but it may possibly be a rounded dorsal valve somewhat hke that of L. mosia (Hall), L. ferruginea Salter, or Lingu- lella (Lingulepis) acuminata (Conrad). Formation and locality. — Passage beds between the Upper Cambrian and the Ordovician: (303c [Ban-ande, 1868a, p. 103]) Subm-bs of Hof, Bavaria, Germany. Lingulella similis (Walcott). Plate XXI, figures 2, 2a-i, 3, 3a-d. Ohohm {Lingulella) similis Walcott, 1898, Proc. U. S. Nat. Mus., vol. 21, pp. 415-416. (Described and discussed as below as a new species.) Shell small, general form ovate, with the ventral valve subacuminate, and the dorsal valve rounded ovate in outhne. There is some variation in the outhne of the valves; this may be seen by comparing Plate XXI, figures 2 and 2b, of the ventral valve, and figures 2a and 2c of the dorsal valve. Sm-face of the shell marked by concentric lines of growth and very fine, slightly irregular, concentric striae. Wliere the outer surface is well preserved, fine radiating striae may be seen with a strong magnifying glass. When the outer layer of the shell is exfoliated the outer surface of the inner layer is marked by fine concentric Imes and ver}^ fine numerous radiating striae; the inner siu-face of the shell shows concentric lines of growth and faint, scattered pits or pimctse. The shell is of medium thickness and formed of a thin outer layer, with one or more inner layers or lamellae. The latter are especially prom- inent toward the front, where they have essentially the same arrangement as in Lingulella acutangula (Roemer). The average length of the ventral valve is from 4 to 5 mm.; width, 2.5 mm. An associated dorsal valve 4 mm. in length has a width of 3 mm. A cast of the interior of a ventral valve shows a clearly defined area of medium length. It is divided midway by a cast of a narrow, strong pedicle furrow, and on each side by flexiu-e lines situated about two-thirds the distance from the pedicle furrow to the lateral margin; a few indistinct striae cross the area parallel with its base. The area of the dorsal valve as seen in a cast is well defined and rather large ; it is marked by fine, transverse striae of growth and indistinct flexure lines. A cast of the interior of the dorsal valve shows a trace of the visceral cavity and a narrow median septum. The only muscle scars observed are the two umbonal scars in the ventral valve (g), figure 2, and the central (h) and the anterior lateral scars (j) of the dorsal valve, figure 2a. OBOLID^. 533 Ohservations. — This very pretty little species occurs in abimdance in the compact gray limestone of the Black Hills associated with numerous fragments of trilobites and Dicellomus nanus (Meek and Hayden). The more elongate forms strongly resemble Lingulella peratten- uata (Whitfield), which occurs in the Middle Cambrian sandstones on the southern margin of the Black HiUs. The species differs, however, from the latter in being more ovate and in having the dorsal valve more obtusely roimded posteriorly. This species may be also com- pared with L. desiderata (Walcott) and L. manticula (White). When flattened in the shales it is difficult to distingmsh it from L. desiderata. A small shell occurs in the "St. Croix sandstone" of the upper Mississippi region that appears to be identical with this species, both in its typical form and in its comparatively wide range of variation. With the somewhat abundant supply of material from both the Black Hills and Wisconsin, I am imable to determine any specific differences that are con- stant. The same is true of the form in the fimestones south-southwest of Potosi, Mssom-i, where it is associated with Linnarssonella girtyi Walcott. The same range of variation occurs in shells from the limestone m the upper part of the Reagan sandstone of Oklahoma, and apparently they are identical. In the shaly sandstones of the Eome formation in Tennessee casts of an apparently iden- tical form occur (PI. XXI, figs. 3, 3a-d). The variation between the Tennessee and South Dakota shells does not appear to be greater than the range of variation among the shells from the same locaHty in the Black HiUs and the localities where it has been identified in Wisconsin and Minnesota. In a hmestone at the north end of the Quinn Canyon Range, Nevada, J. E. Spurr, of the United States Geological Survey, collected a number of small shells that appear to be identical with this species. The shells are well preserved and have the general form of surface charac- teristic of the species. A single specimen of a larger ventral valve has all the characteristics of L. manticula (White). A shell from Middle Cambrian limestones at Mount Nebo, Wasatch Range, Utah, is doubt- fully referred to tliis species. It is associated with Micromitra (IpMdella) pannula (Wliite) and Acrotreta nehoensis Walcott. This form owes its specific name to its marked resemblance to several other forms, from each of which, however, it is distinct. Formation and locality. — Upper Cambrian: (12m) Arbuckle limestone (in the section 7 miles (11.2 km.) north of Springer this horizon is about 30 feet (9.1 m.) above the Keagan sandstone), in NE. J sec. 2, T. 2 S., R. 1 E., .^-d- more quadi-angle (U. S. Geol. Survey), Carter County, Oklahoma. (12n) Limestone of the Reagan sandstone (in the section 7 miles (11.27 km.) north of Springer this horizon is about 240 feet (73 m.) above the porphjrry contact and 40 feet (12 m.) below the Arbuckle limestone), NW. i sec. 1, T. 2 S., R. 1 E., Ai-dmore quadrangle (U. S. Geol. Survey), Carter County; (12k) limestone of the Reagan sand- stone (in the section 7 miles (11.2 km.) north of Springer this horizon is about 225 feet (69 m.) above the porphwy contact and 55 feet (17 m.) below the Arbuckle limestone), on the west side of Honey Creek, near the southeast corner of sec. 35, T. 1 S., R. 1 E., Ardmore quadrangle (U. S. Geol. Survey), Carter County; (12p) about 225 feet (69 m.) above the igneous rocks in the limestone of the Reagan sandstone, at the northwest extremity of the Arbuckle Moun- tains, about 4 miles (6.4 km.) east of Homer, Carter County; all in Oklahoma. (9r) About 45 feet (14 m.) above the porphyry contact in the limestone of the Reagan sandstone, SE. -|- NE. J sec. 2, T. 4 N., R. 13 W.; (9s) about 85 feet (26 m.) below the Arbuckle limestone in the limestone of the Pieagan sand- stone, middle of west half of sec. 13, T. 4 N., R. 13 W.; (9t) about 170 feet (52 m.) above the porphyry contact in the limestone of the Reagan sandstone, SE. i NE. J sec. 2, T. 4 N., R. 13 W.; and (9u) about 195 feet (59.4 m.) above the porphyry contact in the limestone of the Reagan sandstone, SE. ^ NE. J sec. 2, T. 4 N., R. 13 W.; all about 15 miles (24.2 km.) northwest of Fort Sill, Comanche County, Oklahoma. (328a) "St. Croix sandstone" 4 miles (6.4 km.) north of Winfield; and (97a and 97c) "St. Croix sandstone" near Winfield; both in Jefferson County, Wisconsin. (TSb) "St. Crobc sandstone" 50 feet (15.2 m.) above St. Croix River, near the landing at Osceola, Polk County; (328n) "St. Croix sandstone" 2 miles (3.2 km.) south of Osceola, Polk County; and (80a) "St. Crois sandstone" 4 miles (6.4 km.) north of Reedsburg, Sauk County; all in Wisconsin. (86a) "St. Croix sandstone" near Redwing, Goodhue County; (339d) "St. Croix sandstone" at Taylors Falls, Chisago County; (82o) conglomerate beds in the "St. Croix sandstone" in point below Franconia, Chisago County; 534 CMIBRIAN BRACHIOPODA. (97s) "St. Croix sandstone" at Franconia, Chisago County; and (97) "St. Croix sandstone" at Reads Landing, foot of Lake Pepin. Wabasha County; all in Minnesota. Middle Cambrian: {^i) Limestones at the north end of the Quinn Canyon Range, 1 mile (1.6 km.) northwest of the Italian Ranch foothills, Nye County, Nevada. (360d) Siliceous limestones near Pike View, north of Colorado Springs, El Paso County, Colorado. (355a) Shales in Bear Gulch Valley; (88a) limestone about 100 feet {30.5 vi.) above the quartzitic sandstone at the base of the Cambrian in the northern suburbs of Deadwood; (165) limestone on the east side of the valley, in railroad cut about 1 mile (1.6 km.) below the main part of Deadwood; and (17j) limestone in the east endof the town of Galena; all in the Black Hills, South Dakota. (lie) Thin-bedded limestones south-southwest of Potosi, Washington County, Missouri. (10a) Sandy layers of the Rome formation, in western raih-oad cut through Shooks Gap, and (106) shales of the Rome formation, on the roadside at the eastern base of Shooks Gap; both in Bays Mountains, 10 miles (16.1 km.) south- east of Knox^dlle [Keith, 1895, areal geology sheet], Knox County, Tennessee. (9a) Limestone on the south shore of the Holston River at Melinda Ferry, 5 miles (8 km.) southwest of Rogers- ville [Keith, 1896a, areal geology sheet], Hawkins County, Tennessee. (14a) Sandstone of the Rome formation along Fu'st Creek Gap, 4 miles (6.4 km.) north-northeast of Knoxville [Keith, 1905, areal geology sheet], and (374) in the subm-bs of and 4 and 11 miles (6.4 and 17.7 km.) north-northeast of Knoxville; both in Knox County, Tennessee. (138) Shale in the street northeast of Printuf House, Gadsden, Etowah County, and (146) shale in bluff on Coosa River east of Tiirkeytown, 8 miles (12.8 km.) northeast of Gadsden, Etowah County; both in Alabama. (362a) Sandy shale a short distance west of Cave Spring; (138a) shales in the Rome formation west of the ceme- tery .west of Rome; and (140c) shales at edge of hill on the road leading west of Cave Spring; all in Floyd County, Georgia. Specimens tliat are somewliat doubtfully referred to this species occur at the following localities : i Middle Cambrian: (14t) Limestone lying on slope between the Cambrian quartzite and the massive blue lime- stone 100 feet (30.5 m.) above. Mount Nebo Canyon, 3 miles (4.8 km.) southeast of Mona, Juab County, Utah. (92x) Conasauga ("Coosa") shale, at Yanceys Bend, Coosa River; and (90) Conasauga ("Coosa") shale on Edwards's farm, near Craigs Mountain; both southeast of Center, Cherokee Count}', Alabama. LiNGULELLA? SIMPLEX (Barrandc). Plate XXXII, figures 4, 4a-b. Lingula simplex Barrande, 1879, Systeme silurien du centre de la Boheme, vol. 5, pt. 1, PI. CIV, figs, vi: 1-4. (Not described, but figured as a new species. Figs. lA, 4A, and 4B are reproduced in this monograph, PI. XXXII, figs. 4, 4a-b, respectively.) This species, like Lingulella? insons (Barrande), is one of the forms that, with the present evidence, is probably to be referred to Lingulella. All that is known to me of the species is shown in the figures copied from Barrande. Formation and locality. — Lower Ordovioian: (303a) Etage D3 at Trubin; and (303p) Mage. dS in the environ- of Beraun; both [Barrande, 1879b, PI. CIV] in Bohemia, Austria-Hungary. Lingulella taepa (Walcott). Plate XXIII, figures 2, 2a-c. Obolus (Lingulella) tarpa Walcott, 1898, Proc. U. S. Nat. Mus., vol. 21, pp. 417^18. (Described and discussed as below as a new species.) General form elongate ovate, with the ventral valve subacuminate, and the dorsal valve ovate in outline. There is considerable range of variation in the outline of both valves, owing in part, possibly, to distortion. The convexity of the two valves is fairly strong, as far as can be determined from the somewhat compressed condition of the shells in the shale and calcareous sandy shales. The largest ventral valve in the collection has a length of 14 mm. The average length of the ventral valve is from 10 to 12 mm. One 11.5 mm. in length has a width of 8 mm. None of the specimens of the collection show the outer sm'face, and only traces of con- centric and radiating lines have been observed on the mner surface. The shell appears to be moderately tliick, and formed of numerous lamellse that were oblique to the outer layer in the OBOLID^. 535 anterior portions of the shell, in this respect resembling the shell of Lingulella acutangula (Eoemer) (PI. XVII, figs. Im, lo). Casts of the interior of the ventral valve have a moderatelj'- long area divided midway by the cast of a strong pedicle furrow and marked about midway between the pedicle furrow and the lateral margin by a sharp flexure Ime; strise of growth cross the area parallel with its base and arch over the cast of the pedicle furrow. The area of the dorsal valve is relatively short, arching forward slightly at the median portion. The only interior markmgs observed are seen in the casts of the ventral valve where the visceral area and a portion of the main vascular sinuses are imperfectly preserved. Observations. — The external form of this species strongly recalls that of Lingulella acutangula (Roemer), but the material is too imperfect to identif}^ it with the latter. It occurs at a consider- ably lower geologic horizon, and what is preserved of the iaterior markings of the ventral valve iadicates a considerable difference in the position of the visceral area (PL XVII, fig. Ic, and PI. XXIII, fig. 2a). Formation and locality. — Middle Cambrian : (11) Sandstones and shales of the Rome formation, about 1 mile (1.61cm.) east of Post Oalc Springs [Hayes, 1894, areal geology sheet], Roane County; and (11a) sandstone between First and Armstrong creeks, in the southeast corner of the Maynardville quadrangle (U. S. Geol. Survey), Union County; both in Tennessee. Lingulella texana Walcott. Plate XLIX, figiu-es 3, 3a. Lingulella texana Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, p. 71, PI. VIII, iig. 5. (Characterized aa below as a new species. Fig. 5 is copied in this monograph, PI. XLIX, fig. 3.) This is a small but distinctly marked species, represented by two dorsal valves occm-ring in the Upper Cambrian limestones of central Texas. The dorsal valves are oval, and quite strongly convex. The shell appears to have been rather thick, and the outer surface is marked by strong, radiating strise, a feature which is characteristic of the species. They are crossed by fine, concentric strise and lines of growth. The position of the muscle scars and the size and character of the area are shown by Plate XLIX, figure 3a. Formation and locality. — Upper Cambrian : (369) Sandstones at the base of the Elvins formation, in the eastern limits of the town of Flat River, St. Francois County, Missouri. (69) Limestones near Honey Creek; and (70) limestone near Morgans C'reeh; both in Burnet County, Texas. Lingulella torrentis (Matthew). Plate XXXV, figure 7. Leptobolus torrentis Matthew, 1903, Geol. Survey Canada, Rept. Cambrian Rocks Cape Breton, pp. 74-75, PI. VI, fig. 1. (Described as below as a new species. The specimen represented by fig. 1 is redrawn in this monograph. Pi: XXXV, fig. 7.) Leptobolus atavus tritavus Matthew, 1903, idem, p. 109, PL VI, figs. 5a-c. (Characterized as a new variety.) The original description by Matthew follows: Shell thin, surface shining. Form elongate oval. Ventral valve obtusely pointed at the back, somewhat acutelj' rounded in front; elevated along the middle; some- what flattened along the sides within the margin. By decortication a low boss and a transverse furrow behind it are exposed on the mold, about three-quarters of the length of the valve from the hinge; if this boss marks the front of the callus, the central muscles are unusually far forward, more advanced even than in L. atavus of the Etcheminian terrane. There are faint impressions of the lateral septa on the sides of the valve. The surface of the shell is covered with minute, low tubercles, cancellate in arrangement; through these can be traced faint parallel lines, concentric to the umbo. Along the median third in places can be seen about six broad, flat ridges, radiating from the direction of the umbo; these break the continuity of the concentric ridges. Length, 3 mm.; width, 2 mm.; depth, 0.5 mm. The ventral valve of "Leptobolus atavus tritavus" Matthew is similar in form to the type of Lingulella torrentis. Compare figures 1 and 5a of Matthew [1903, PI. VI]. The surface characters 586 CMIBRIAN BRACHIOPODA. appear to be identical. Tlio dorsal valve is elongate oval in outline, resembling the same valve in Lingulella atava (Matthew). Formation and locality. — Middle Cambrian: (344f [Mailhcw, 190S, p. 7-2]) Shales of the Coldbrooh terrane of Matthew, on Dugald Brooh, Indian River; and (344e [Matthew, 1303, p. 78]) shales of Division Eld of Matthew's [1903, pp. 28 and 29] Etcheminian, on Boundary Brook, eastern side of the Escasonie Indian Reservation; both in eastern Cape Breton, Nova Scotia. Lingulella teipaeilis (Matthew). Text figures 44a-l, page 537; Plate XLV, figures 2, 2a-f. Obolm triparilis Matthew, 1902, Trans. Roy. Soc. Canada, 2d ser., vol. 8, sec. 4, No. 3, p. 94, PI. I, figs. 2a-c. (Dis- cussed as a new species.) Obolus discus Matthew, 1902, idem, p. 94, PI. I, figs. 3a-d. (Mentioned as a new species.) Lingulella loyigovalis Matthew, 1903, Geol. Survey Canada, Rept. Cambrian Rocks Cape Breton, pp. 123-125, PI. VII, figs. 3a-f. (Described and discussed as a new species. Figs. 3b and 3d are represented in outline by text figs. 44h and 44h', respectively, p. 537, of this monograph.) Obolus {Eoobolus) triparilis Matthew, 1903, idem, pp. 136-137, PI. VIII, figs. 4a-c; PI. IX, figs. la-b. (Described and discussed as a new species. PI. VIII, figs. 4a-c, is copied from Matthew, 1902b, PI. I, figs. 2a-c; PL VIII, fig. 4a, and PL IX, fig. la, are represented in outline by figs. 44b and 44b', respectively, p. 537, of this monograph.) Obolus (Eoobolus) discus Matthew, 1903, idem, pp. 138-139, PL VIII, figs. 3a-d. (Described and discussed as a new species. Figs. 3a-d are copied from Matthew, 1902b, PL I, figs. 3a-d; figs. 3aand 3c are represented in outline by figs. 44a and 44a', respectively, p. 537, of this monograph.) This species is distinguished from Lingulella (LinguJepis) gregwa (Matthew) by its outhne. The range of variation in its form covers both the types of the species and the type^ of "Lin- gulella longovalis" Matthew and "Obolus (Eoobolus) discus" Matthew. Matthew assigns specific value to variations in length and breadth of the visceral areas of the valves. I do not find that this holds good, as the shells from the same layer of rocks and not distinguishable by other characters vary in the length of the visceral area of the dorsal valve from a point back of the center to nearly the front of the valve. There is also considerable variation in the ventral valve. On the same shell there is a variation of the surface characters from the nearly plain, concentric strise to undulating striae, with minute points on the crest. This is also true of the surface of Lingulella {Lingulepis) gregwa (Matthew). The "central" scar in the dorsal valve, mentioned by Matthew [1903, p. 136] as charac- terizing "Obolus (Eoobolus) triparilis," is at the bifurcation of the median ridge, and appears to be a shght depression just in advance of the bifurcation and not a true muscle scar. The variation in outhne of the valves is shown in figures 44a-l. No specimens among the types sent by Matthew nor in our material show areas like those represented by figures 44b' and 44h'. The area is not preserved on the dorsal valves of L. triparilis sent by Matthew, and the area of the dorsal valve of his "Z-. longovalis" does not extend so far down the lateral slojjes of the shell as represented in the figure. The variation in the length and strength of the visceral area in the two valves is also outlined from specimens showing their position. Among the specimens from the same layer of rock there is a transition in form from Lingulella triparilis to Lingulella (Lingulepis) longi- nervis (Matthew) of a somewhat later stratigraphic horizon. This is illustrated in figures 44f-k. The surface characters are of -the same type in Lingulella (Lingulepis) gregwa (Matthew), L. (L.) longinervis (Matthew), and Lingulella triparilis. "Obolus (Eoobolus) discus" Matthew appears to be based on imperfect specimens of the short, broad form of L. triparilis. With the types of "0. (E.) discus," L. triparilis, and "L. longovalis" before me, I am not able to discover difi^erences of specific value between them. All have the same surface characters, and the gradations in form unite them into one species. Formation and locality. — Middle Cambrian: (13t' and 13t)o Sandstones at the base of Division Elh; (344g) [Matthew, 1903, p. 77]) shales of Division Elc; (13t") sandstones of Divisions Elc and Eld; (344i [Matthew, 1903, a 13t is the type locality, tliough the specimens in the United States National Museum collections to which that number was assigned were collected later than Matthew's type specimens. OBOLIDiE. 537 p. 79]) sandy layers in the shales of Division Ele; and (lOp) sandstone just below the waterfall in Division E2b; all in Matthew's [1903, p. 21] Etcheminian, on Dugald Brook, Indian River Valley, eastern Cape Breton, Nova Scotia. (307d [Matthew, 1903, p. 79]) Sandy limestone of Division E2a? of Matthew's Etcheminian, on Young (McFees) Point, George River, Cape Breton, Nova Scotia. FiGUEE U.—Lingulella triparilis (Matthew); outlines illustrating variation in form of shells now referred' to Lingulella triparilis. a, a', Ventral and dorsal valves of " Obolus (Eooholus) discus" [Matthew, 1903, PI. VIII, figs. 3a and 3e]. b, b', Ventral and dorsal valves of Lingulella triparilis [Matthew, 1903, PI. VIII, flg. 4a, and PI. IX, flg. la], c-g, c'-g', Ventral and dorsal valves from Locality 13t", sandstones of Division Ele of Matthew, Dugald Brook', illustrating the gradation in form between shells referred to L. triparilis and " L. longoualis." h, h', Ventral and dorsal valves of " L. longoralis" [Matthew, 1903, PI. VII, figs. 3b and 3d]. i-l,i'-V, More elongate ventral and dorsal valves from speci- mens associated with those represented by c-g, Lingulella tumid a Matthew. Plate XXIV, figures 7, 7a-d. Lingulella tumida Matthew, 1899, Bull. Nat. Hist. Soc. New Brunswick, vol. 4, pt. 3, No. 18, p. 200, PL I, fio-s. 2a-c. (Described as a new species.) Obolus (Lingulepis) gregwa Walcott (in part) [not (Matthew)], 1901, Proc. U. S. Nat. Mus., vol. 23, p. 692-694. (Mat- thew's Lingulella tumida is here referred to and described with Lingulella (Lingulepis) gregwa.) Lingulella tumida Matthew, 1903, Geol. Survey Canada, Rept. Cambrian Rocks Cape Breton, p. 123, PI. VI, figs. 6a-c. (Described and discussed. Figs. 6a-c are copied from Matthew, 1899b, PI. I, figs. 2a-c.) This shell resembles Lingulella martinensis Matthew and some forms of Lingulella (Liv^ gule-pis) exigua (Matthew) in outline of the valves. At first I thought it should be placed with the latter species, which I had [1901, p. 692] by error identified with Lingulella (Lingulepis) gregwa (Matthew). It is uniformly smaller than L. (L.) exigua, and differs in the more uniform concentric Unes and striae of growth. 538 CMIBRIAN BRACHIOPODA. Matthew's material is poor, but in the collections made by S. Ward Loper there is an abundance of specimens showing some variations in form. The surface is marked by strong, concentric lines of growth, with narrow bands of finer and somewhat minutely irregular strife. Depressed, irregular, and bifurcating radiating Unes show on very perfectly preserved shells. Formation and locality. — Middle Cambrian: (13i) Sandstones of the "Joliannian" Division of Matthew's section, on Gillis Brook, East Bay, east of Bras d'Or Lake; and (13r) sandstone at a little different horizon than that of Locahty 13i, on Gillis Brook, East Bay, east of Bras d'Or Lake; and (13n')a sandstones of Division ESe of Mat- thew's [1903, p. 21] Etcheminian, Dugald Brook, Indian River; all in eastern Cape Breton, Nova Scotia. LlNGULELL.i UPIS (Walcott). Plate XXXVI, figures 3, 3a. Obolus (Lingulella) upis Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 331-332. (Described and discussed as below as a new species. ) This is a small, elongate shell of the group to which Lingulella ora (Walcott) belongs. It differs from the latter in being more elongate and in its marked surface characters, and from L. collicia (Matthew), L. fiumenis (Matthew), L. cania (Walcott), and allied forms, in haying a thick, strong shell and highly characteristic exterior surface. The shell is thick, the anterior portions being made up of numerous lamellae oblique to the exterior surface, in this respect resembling some of the species of Obolus having thick shells. The exterior surface is marked by concentric lines of growth, with very fine, some- what irregular striae between them. These show very distinctly in the anterior portion of the shell. Further back they become very irregular, giving a crenulated appearance to the striae and Hnes of growth, and the surface looks as though it was formed of thin, imbricating scales or lamellse. Ohservations. — The surface of Lingulella upis suggests that of Obolus ( Westonia) euglyphus (Walcott), but I have been unable to find traceg*of the transverse lines characteristic of Westonia. Formation and locality. — Upper Cambrian: (14g and 14i) 6 Upper part of the limestones exposed 1 mile {1.6 km.) west of Cherokee, San Saba County; and (14b) limestone on Cold Creek, at north end of gorge opposite the north end of Sponge Mountain, 2 miles (3.2 km.) south of the San Saba County line, in Llano County; both in Texas. Lingulella wanniecki Eedlich. Plate XXXIX, figures 1, la-n. Lingulella wanniecki Redlich, 1899, Mem. Geol. Survey India, Paleontologia Indica, new ser., vol. 1, No. 1, The Cambrian Fauna of the Eastern Salt Range, p. 7, PL I, figs. 9a-d. (Described and discussed as a new species.) Obolus {Lingulella) wanniecki (Redlich), Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 332. (Described and dis- cussed as below.) General form broa'dly ovate, with the ventral valve obtusely acuminate and the dorsal valve rounded subtriangular; convexity moderate in the specimens embedded in argillaceous shales. There is considerable range of variation in the outline of the valves; this is shown in Plate XXXIX, for the ventral valve by figures 1, la-f, and for the dorsal valve by figures Ig-m. All that is known to me of the interior markings of the ventral valve is shown bj^ figures Id-f, and of the dorsal valve by figures 11-n. The surface of the shell is marked by concentric lines of growth and very fine closely undulating raised strias that inosculate so as to give the surface a granulated appearance. This type of surface occurs on Lingulella isse (Wal- cott) and L. upis (Walcott). The anterior layers of the shell are marked by radiating and concentric strias, and the interior of the shell has scattered jDunctae in addition to the radiating and concentric striae. The shell is relatively thick and formed of several layers or lamellae in addition to the very thin outer ornamented layer. The visceral area of the ventral valve is short, and the main vascular sinuses are about halfway between the center of the shell and the lateral margins. In the dorsal valve the o 13n' is the type locality, but the specimens in the United States National Museum to which that number is assigned were collected later than the type specimens. t> Hi is the type locality. OBOLID^. 539 visceral area is well developed beyond the center of the shell, and the vascular sinuses are farther out proportionately than in the dorsal valve. The central and anterior lateral muscle scars are placed on an elevated central ridge, on each side of a sharp median septum. Ohservations . — This very pretty little shell occurs in great numbers in the dark argilla- ceous shales with. RedlicTiia noetlingi (Redlich). Redlich [1899, p. 7] states that it is the only species of the genus in the collection sent to him. In the collections made by Fritz Noetling I find associated mth Redlichia noetlingi, Lingulella wannieclci, L. fuchsi Redlich, Acrothele (Jtedlichella) granulata (Linnarsson) ; also specimens of a species of undescribed Hyolithes. Among the American species of Lingulella, L. wanniecki may be compared in form with L. desiderata (Walcott) and L. oweni (Walcott). Its surface is much like that of L. upis (Walcott) and L. ora (Walcott). It is distinct from all described species when its form and sur- face are taken into consideration, as there is no species with its subtriangular form that has its granulated surface. The formations containing this fauna are referred to the Middle Cambrian, as there is no evidence that the Cambrian fauna of India above the upper "Annelid sandstone," as described by Noetling and Redlich, is older. Formation and locality. — Middle Cambrian: (15r) « Dark argillaceous shales at Khussak, Salt Range, India. Lingulella welleki (Walcott). Plate XXXVIII, figures 4, 4a-b. Obohis (Lingulella) welleri Walcott, 1902, Proc. U. S. Nat. Mus., vol. 25, p. 608. (Described and discussed essen- tially as below as a new species.) General form elongate ovate, with the ventral valve subacuminate and the dorsal valve subelliptical. Owing to the more or less crushed condition of all the specimens the exact convexity of the entire valve is unknown. Surface of the shell marked by numerous elevated concentric lines of growth and very fine slightly irregular interstitial concentric striae. Wlien the outer edge is exfoliated the inner layers show fine radiating striae and con- centric lines of growth. Nothing is known of the interior surface of the shell. The shell appears to have been relatively tliin and formed of several layers or lamellae. A ventral valve 14 mm. in length has a width of 9 mm. and a dorsal valve 10 mm. in length has a width of 7.5 mm. In both valves the mdth is slightly increased by the flattening of the shell. Observations. — Tliis species occurs in association with Oholus ( Westonia) stoneanus (Whit- field) Lq an arenaceous, magnesian limestone. It difl^ers from described species of Lingulella in the elliptical form of its dorsal valve and the strongly filose concentric striae of the outer surface. The dorsal valve has the outline of that of Oholus ( Westonia) stoneanus but the ventral valve is more acuminate and the characteristic Westonia surface of the latter is absent. Some specimens of 0. (W.) stoneanus have the transverse imbricating lines only on the postei-ior half of the valve, in which case the anterior half is much like that of Lingulella welleri. The specific name is given in honor of Prof. Stuart Weller, who discovered the locality. Formation and locality. — Upper Cambrian: (lie) Hardyston quartzite [Weller, 1900, pp. 10 and 12], O'Donnell and McManniman's quarry, Newton, Sussex County, New Jersey. Lingulella winona (Hall). Plate XVIII, figures 3, 3a-b. Lingula idnona Hall, ISCiS, Sixteenth Rapt. New York State Cab. Nat. Hist., p. 126, PI. VI, fig. 9. (Described as a new species; see p. 540 for copy.) Lingula winona Hall, 1867, Trans. Albany Inst., vol. 5, p. 102, PI. I, fig. 9. (Copied from preceding reference.) a Specimens from the type locality were given to the United States National Museum and this number was assigned to them. 540 CAMBRIAN BRACHIOPODA. Lingula winona Hall, Sardeson, 189G, Bull. Minnesota Acad. Nat. Sci., vol. 4, No. 1, pt. 1, p. 96. (Cliaracterizes specimens from new locality.) LingulcUa winona (Hall), Schuchei.t, 1897, Bull. U. S. Geol. Survey No. 87, p. 258. (Merely changes generic refer- ence.) The original description bj' Hall follows: Shell small, subquadrilateral, the front nearly straight; sides nearly straight and parallel; apex obtuse, the cardinal margins sloping at an angle of SO degrees. Sm-face marked by fine concentric striae. A cast of part of a ventral valve from Osceola, Wisconsin, that appears to belong to tliis species, shows the visceral area and the main vascular sinuses (PI. XVIII, fig. 3). This shell is more convex and has a more rounded outline than the type shell, but I tliink that this is owing to the fact that the type shells are pressed flat in the sandy shales and to a degree distorted. Flattened shells at Osceola are much more quadrate in outline. The species has been found at a number of localities, but very little more can be added to the original description. The shell, although very small, is built up of two or more layers that are lamellose toward the front of the shell. The outlines of the two valves when compressed are shown by Plate XVIII, figures 3 a and 3b. The nearest form to Lingulella winona is L. mosia (Hall) of the Upper Cambrian. It differs in the uniformly smaller size and its regular subquadrate outline. The specific name is derived from Winona, Minnesota. Formation and locality. — Upper Cambrian: (78 and 78c) "St. Croix sandstone," quarry near St. Croix River in suburbs of Osceola, Polk County; (85x) upper beds of the "St, Croix sandstone" near Mazomanie, Dane County; (lOv) shaly beds in the "St. Croix sandstone," at Fox Glen, 8 miles (12.8 km.) east of Baraboo, Barabod quadrangle (U. S. Geol. Survey), Sauk County; (79) "St. Croix sandstone" in bluff near Hudson, St. Croix County; and (85s) "St. Croix sandstone" at Prairie du Sac, Sauk County; all in Wisconsin. (113) "St. Croix sandstone " at La Grange Mountain (or Barn Bluff), near Red Wing, Goodhue County, Minnesota. (341) Near Lansing, Allamakee County, Iowa. LlNGCXELLA WINONA CONVEXA (Walcott). Plate XVIII, figures 4, 4a-d. Oholus {Lingulella) imnona convexus Walcott, 1901, Proc. U. S. Nat. Mus., vol. 23, p. 691. (Discussed as below as a new variety.) A small relatively convex shell occurs abundanth* in the brown sandstones at Osceola that appears to be an intermediate form between Lingulella winona (Hall) and L. mosia (HaU). It differs from L. mosia in being a shorter shell, and from L. winona in the more regularly ovate to semicircular dorsal valve and more acuminate ventral valve. Observations. — The group of shells represented by L. winomi, L. m,osia, and their varieties appears to range from the Middle Cambrian beds of Hudson, Wisconsin, up and into the Upper Cambrian beds of Osceola, Wisconsin. There is so much variety of form owing to the condi- tions of preservation that it is very difficult to be always sure of the correctness of the specific reference. The variety convexa may be only the uncompressed form of L. winona, which is usually flattened in the shaly sandstones, or it may be a distinct species. From the material available for comparison tliis can not be clearly determined. Formation and locality. — Upper Cambrian: (78, 78s, and 78c)<» "St. Croix sandstone" in quarry near St. Croix River in suburbs of Osceola, Polk County; (79) "St. Croix sandstone " in bluff near Hudson, St. Croix County; (85xand S85x) upper beds of the "St. Croix sandstone," near Mazomanie, Dane County; (100) "St. Croix sandstone" near Menomonie, Dunn County; (79a) "St. Croix sandstone" in quarry and ledge, 0.5 mile (0.8 km.) southeast of the county courthouse, Menomonie, Dunn County; (80) "St. Croix sandstone" 0.66 mile (1.1 km.) southwest of the railway depot, Menomonie, Dunn County; (85s) "St. Croix sandstone" at Praii-ie du Sac, Sauk County; and (135) "St. Croix sandstone " near Trempealeau, Trempealeau County; all in Wisconsin. (75) "Tonto " sandstone, near the water's edge at the mouth of Kanab Canyon, where it enters the Grand Canyon of the Colorado, Arizona. a 78 is the type locality. OBOLIDJi;. 541 LiNGULELLA wiETHi (Barrande). Plate XXX, figure 7. lAngula viirtM'BA'RRAysTiE, 1868, Faune silurienne des environs de Hof, en Baviere, p. 101, fig. 63. (Described and discussed in French as a new species. Fig. 63 is reproduced in this monograph, PI. XXX, fig. 7.) Lingula wirthi Barrande, 1868, Neues Jahrb. fiir Mineralogie for 1868, p. 691, unnumbered plate, fig. 63. (Copy of preceding reference.) Tliis is a more elongate shell than Oholusf havaricus (Barrande), and is known only by- several casts. It has a length of 15 imn.; greatest width, 9 mm. In many respects it resembles Lingulella davisi (McCoy) of the Lingula flags of Wales. The outer surface is marked by con- centric lines and strise, as far as can be determined from the casts. Formation and locality. — Passage beds between the Upper Cambrian and the Ordovician: (303c [Barrande, 1868a, p. 101]) Suburbs of Hof; and (303f [Pompeckj, 1896a, pp. 7 and 8]) railway cut near Schellenberg, a little distance back of the railway station at Neuhot, near Hof; both in Bavaria, Germany. LiNGXJLELLA ZEUS n. Sp. Text figure 45. This species is represented by one very minute specimen, a poorly preserved interior of a suborbicular ventral valve, showing a fairly well defined area. The exterior surface was covered with strong concentric striae. Observations. — This specimen is of particular interest as the only representative of the genus Lingulella from Scotland, where it occurs associated, with Olenelloides armatus. The species is too poorly preserved for further description or comparison. Formation and locality. — Lower Cambrian : (316c) Shales fi-om Locality M4197d of the Geological Survey of Scotland, a band probably equivalent to either 6 or 7 of the section on the north slope of Meall 4 Ghiubhais [Peach and Home, 1907, p. 414] on the Bruachaia; River, 2 miles (3.2 km.) east-northeast of the Kinlochewe Hotel, Loch .^ ,,. t- , ■,, ,. -r^ , . „ , , Figure is.— Lingulella zeus n. sp. Maree, Ross-shire, Scotland. Interior of a ventral valve, the type and only specimen, x 12, LiNGXJLELLA sp. Undt. a. froinLocality316c,LowerCam- brian shales near Loch Maree, Plate XXX, figure 13. Ross-shire, Scotland. Thespeci- men is numbered M4197d in There are two specimens of the dorsal valve in the collection from lur -e" ofsToUand'!' ^""^""'"'"'^ the Olenus truncatus zone. The outer surface is marked by fine radi- ating and concentric striae, and the inner surface by large punctse, scattered, as far as known, in the anterior half of the valve. Formation and locality. — Upper Cambrian : (310k) Oeland Island, Sweden. Lingulella sp. undt. b. Imperfect specimens of a small, rather broad form of Lingulella occur in Middle Cambrian shales at York, Pennsylvania. The outline of the shells is somewhat like that of Oholus willisi (Walcott), but the material is too poor for specific determination. Formation and locality. — Middle Cambrian : (48d) Argillaceous shales in the railroad cut beside the gas house, York, York County, Pennsylvania. LEPTEMBOLON Mickwitz, subgenus of LINGULELLA. [Xzr.zir, small; and 'i/t^o/.ov, a wedge.] Obolus (Leptembolon) Mickwitz, 1896, M^m. Acad. imp. sci. St.-Petersbourg, 8th ser., vol. 4, No. 2, p. 199. (Char- acterized and discussed as a new subgenus; see below for translation.) Obolus (Leptembolon) Mickwitz, Walcott, 1908, Smithsonian Misc. Coll., vo? . 53, no. 4, PL XI, and pp. 142 and 144. (Classification of subgenus.) The original description by Mickwitz follows: The subgenus Leptembolon is based on a species of Obolus, which externally resembles Lingula very closely, and in fact was by earlier authors regarded as such. The specimens of the internal surfaces of the valves, however, 542 CAjMBRIAN brachiopoda. showed, together with some suggestions of the last-mentioned genus [Lingula], unmistakable marks of the genus Oholus, so that the species, which would not be assigned to any of the other groups, had to be ranked in a special subgenus of Eichwald's genus. The internal characteristics of the Cambrian and Siliuian Lingulse have not hitherto been established so com- pletely as to render it possible to compare the organization of this extinct group in detail with the recent Lingula. It is probable that more accurate knowledge of these oldest Lingulse will lead to a change in the generic designation. A similar uncertainty of course exists also in regard to the relations of the genus Obolus to the above-mentioned Lin- gula, and if it be possible to ascertain the internal features of the latter to the same extent as in the genus Oholus, 0. lingulse/ormis will probably become the connecting link between these old extinct genera. LiNGULELLA (LePTEMBOLOX) LlNGULiEFORMIS (Mickwitz) . Plate XIV, figures 5, 5a-b. Obolus (Leptem.bolon) lingulxforrais Mickwitz, 1S96, M6m. Acad. imp. sci. St.-Petei-sbourg, 8th ser., vol. 4, No. 2, pp. 200-204, PI. Ill, figs. 10-17. (Described and discussed in German as a new species; see below for trans- lation. Figs. 17a-b are copied in this monograph, PL XIV, fig. 5.) Obolus (Leptembolon) lingulieforrtvis solidus Mickwitz, 1896, idem, pp. 204-20-5, PL III, figs. IS and 19. (Described and discussed in German as a new variety.) The original description by Mickwitz follows : Shells moderately large, quite flatly arched. Outline pointedly oval to subtriangular. Beak and posterior part of shell laterally somewhat flattened, forming two slightly pronounced roundish edges, which converge to the tip of the beak. Anterior part of shell similarly flattened toward the anterior border. Surface of shell very smooth, vei-y lustrous, like varnish. Concentric strise very fine and regular, especially sharp cut at the posterior borders. Growth lamella indistinctly bordered. In age, clearly distinguishable by the somewhat projecting borders of the lamellas. Anterior and lateral borders very thin, sharp-edged, brittle, lying in the plane with the uncovered umbonal borders. Posterior part of the shell scarcely thickened, area more iu shape of covering of the hollow tip of the beak. Pleurocoelic part of the area somewhat prolonged into the lateral borders. Peduncular groove very broad, somewhat diminished toward the tip of the beak, lying deep but only flatly arched on account of the deficient thickening of the beak. Traces of the pseudo-area rectilinear, converging to the tip of the beak. Splanchnocoele of the large shell (ventral valve) drawn forth, anterior point of the same bordered in the shape of a bow, and somewhat projecting. Terrace of the thickening of the posterior part of the shell diverging into the brachiocoele, longitudinally palmately striate. Central groove of large shell very flat, posterior pai-t indefinitely bor- dered, tip drawn out, parallel bordered and anteriorly semicircularly rounded. Corneous processes of the small shell (dorsal valve) strongly receding, sinus indefinitely flattened. Median swelling of small shell strongly developed, beginning in the sinus as a thin, roundish ridge, gradually swelling, reclining beyond the places of attachment of the anterior lateral muscles, and ending shortly before the anterior border in the shape of a pestle. Principal vessels distinguishable in their beginnings, not traced in the brachiocoele. Peripheral canals and accessory vascular furrows in both shells only distinguishable in indistinct traces. Places of attachment of the umbonal muscles large, longi- tudinally striate, not to be separated from tLe place of attachment of the peduncular muscle in the large shell. Places of attachment of the central and outside lateral muscles to both sides of the central groove of the large shell, separated from each other and from those of the middle lateral muscles. The latter lie before the semicircularly bordered apex of the central groove. Central muscles (with their advance corresponding to the growth of the animal) lea\'ing behind, in the small shell, a row of traces, which converge into the sinus. Places of attachment of the combined outside and middle lateral muscles, as also those of the transmedian muscles of the small shell, very near the border of the shell. Observations: The shells of 0. lingulieformis show a different form of outline in their youth than in theii- age. For the species of the subgenus Euobolus, we have demonstrated a proportional gi'owth, and tlie same aiso takes place in the species of the other subgenera, as the consideration of the concentric stri« teaches, which marks the stages of age. The form of outline remains the same, except in the very first stages of youth. In 0. lingulsefonnis the outline of the shell is elliptic until in old age, and then first begins to become subtriangular through the growth lamella pro- jecting mostly at the anterior border and anterior lateral borders. Self-e-\adently, the separation of the substance of the shell takes place also in this stage along the entire border of the shell (including the ai-ea), but the lamellas run, so far as their external part (which foiTus the siu-face of the shell) comes into consideration, so sharply into the lateral borders that they do not help to broaden the posterior borders of the shells, but only to thicken them vertically. The outline of the posterior part of the shell, therefore, remains the same, while the anterior part steadily gains in breadth. In connection with this manner of formation stand the extraordinarily sharply sculptured concentric striae at the lateral borders of the shell, which are closely crowded against each other. This characteristically subtriangular outline, which, in connection with the flat arching of the shell, marks the typical form of 0. lingulieformis, is, however, in some specimens given to essential deviations. The beak becomes OBOLID^. 543 broader, and the form of the outline approaches more to the elliptic. At the same time the shell is much more strongly arched. A small shell whose outline deviates only slightly from the typical form is arched much more than tiie nor- mal specimens. These transition forms point, as we see, toward the variety solidus. The typical form shows two slightly pronounced roundish edges which converge into the tip of the beak and are caused by a lateral flattening of the posterior part of the shell. In like manner the anterior part of the shell is somewhat flattened toward the anterior boi-der. These characters are first plainly perceptible by reflected lio-ht, and are much less developed in the described roundish forms. A peculiar correlation also seems to exist between the form of the shell and the strength of the shell. The latter is the slightest in the typical form, increases in the roundish form, and acquires the maximum in 0. lingulxformis solidus. The thinness of the shell of the species in question is pronounced, especially in the deficient thickening of the tip of the beak, which in this regard reminds one of the recent lingulas. Here, as well as there, the broad posteriorly diminished pedunculai- groove is shallow and only indefinitely bordered, and sunk in the area of the large shell. 0. lin- gulxfoi-inis reminds one, more than all other species of Eichwald's genus, in the fonnation of the area of the small shell, of the recent Lingula with which this part is, to be sm'e, in a still more pronounced inanner, a mere covering of the thin- walled tip of the beak with the corneous area lamellae. The configm-ation of the inner surface of the shell is, in relation to the deficient thickening, quite distinctly devel- oped. In its projecting tip the splanchnocoele of the large shell in some measure resembles the con-esponding formation of Lingula anatina. On the other hand, the small shell shows the three-lobed form, which is peculiar to the genus Obolus and is continued by the aberrant position of the places of attachment of the muscles. The thickening of the posterior part of the large shell is reduced to a wall-like rim whose pointed upper edge incloses the parietal band. The decli-\dty of this rim into the brachioccele is quite steep and marked at its middle, circular-formed, projecting part by somewhat diverging longitudinal swellings palmately arranged ; the slope into the splanchnocoele is flatter and is lost in the indefinitely bordered central groove, from which only the strongly drawn forth, parallel-bordered, somewhat anteriorly broadened, and rounded-off tip is clearly distinguishable by a slight but sharply bordered depression. As often mentioned, the places of attachment of the middle lateral muscles, which are removed from the places of attachment of the central muscles, and united to one surface, lie before the tip of the central groove. The places of attachment of the central muscles are oval and lie on both sides of the drawn-out apex of the central groove. They show a coarse transverse striation, which is posteriorly continued farther than the places of attachment, and owes its origin to the gradual advance of the central muscles, whose traces were only partly covered by a slight secretion of lime. A similar condition takes place with the places of attachment of the outside lateral muscles of the large shell, which lie, as with Schmidtia, close to the inner sides of the principal vascular canal, far removed from those of the cen- tral muscles, and somewhat pushed back. Yet more striking is this succession of exposed traces with the places of attachment of the central muscles of the small shell, in which it may be followed from the inner sides of the corneous processes to the extreme tip of the sinus. The last-mentioned small shell of the variety solidus shows very distinctly — namely, at the right side — the places of attachment of the combined middle and outside lateral muscles as well as those of the transmedian muscles, while the umbonal muscle has left less distinct traces. The first-mentioned places of attachment lie so close to the border of the shell that the pleurocoeles are reduced to small, ribbon-shaped strise. This form of the pleurocoele stands in connection with the previously mentioned law of growth of the shells. In the large shell the places of attachment of the combined anterior lateral and transmedian muscles, likewise on the right side, are quite distinctly pronounced, while the places of attachment of the divided umbonal muscles and peduncular muscle form a somewhat indefinitely bordered, coherent surface, which is longitudinally striate in the middle. Very striking to the eye is the strongly developed median swelling of the small shell, which separates the dis- tinctly depressed oval places of attachment of the anterior lateral muscles, and reaches, with its pestle-shaped swelled ends, nearly to the anterior border of the shell; of the circulatory system only the posterior parts of the principal vessels (with the exit out of the splanchnocoele) are unfailingly distinguishable. The concentric striae of the small shell are insufficiently covered furrows of separation of the growth lamellae. Formation and locality. « — Passage beds between the Upper Cambrian and the Ordovician: "Glauconite sand- stone" at the following localities: (396) at Baltischport, 30 mUes (48 km.) west of Reval; (396a) at Leppiko near Leetz, on the eastern side of the Baltischport peninsula, about 25 miles {40.3 1cm.) west of Reval; (396b) at Fall, 15 miles (24 km.) west of Reval; (396c) at the mouth of Fahna Brook, east of Fall, about 15 miles (24 km.) west of Reval; (396d) at Domglint in Reval; and (396f) in the western part of the east Baltic region; all [Mickwitz, 1896, p. 203] in the Gov- ernment of Esthonia, Russia. Upper Cambrian: (395) Obolus sandstone at Joa, near Jegelecht, 12 miles (19.3 km.) east of Reval, Government of Esthonia, Russia. o Localities 395 and 396a are represented in the United States National Museum eoUections. 544 CAMBRIAN BRACIilOPODA. LINGULEPIS HaU,a subgenus of LINGULELLA. [Ling^ula, a tongiie; and hT:i<:, a scale.] • Lingulepis Hall, 1S63, Sixteenth Ann. Rept. New York State Cab. Nat. Hist., p. 129. (Described as a new genus.) Lingulepis Hall, Meek and Hayden, 1865, Smithsonian Contrib. Knowl., No. 172, Paleontology Upper Missouri, pt. 1, pp. 1 and 2. (Described and discussed.) Lingulepis Hall, 1867, Trans. Albany Inst., vol. 5, p. 106. (Copied from Hall, 1863, p. 129.) Lingulepis Hall, Dall, 1870, Am. Jour. Conchology, 2d ser., vol. 6, pt. 2, pp. 154 and 161. (Described.) Lingulepis Hall, Meek, 1871, Proc. Acad. Nat. Sci. Philadelphia for 1871, vol. 23, pp. 186-187. (Notes on genus in discussion of "Lingulella? lamborni.") Lingulepis Hall, Zittel, 1880, Handbuch der Palseontologie, Bd. 1, Abth. 1, p. 664. (Described in German.) Lingula {Lingulepis) (Hall), Oehlert, 1887, Manuel de conchyliologie, by Fischer, p. 1261. (Described in French.) Lingulepis Hall, Hall and Clarke, 1892, Eleventh Ann. Rept. State Geologist New York for 1891, pp. 231-232. (Described.) Lingulepis Hall, Hall and Clarke, 1892, Forty-fifth Ann. Rept. New York State Museum for 1891, pp. 547-548. (Copy of preceding reference.) Lingulepis Hall, Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, pp. 59-62, and 164. (Origi- nal description copied, p. 59; genus described and discussed, pp. 59-62; and derivation of genus shown graphi- cally, p. 164.) Lingulepis Hall, Schuchert, 1897, Bull. U. S. Geol. Survey No. 87, p. 258. {Lingulella and Lingulepis compared.) Lingulepis Hall, Walcott, 1897, Am. Jour. Sci., 4th ser., vol. 3, p. 404. (Re-refers all the species that have been placed under Lingulepis.) Oholus {Lingulepis) (Hall), Walcott, 1899, Mon. U. S. Geol. Survey, vol. 32, pt. 2, pp. 443-444. (Copy of preceding reference, except that Lingulepis and Lingulella are made subgenera of Oholus.) Oholus {Lingulepis) (Hall), Walcott, 1901, Proc. U. S. Nat. Mus., vol. 23, p. 683. (Characterized.) Lingulepis Hall, Matthew, 1902, Trans. Roy. Soc. Canada for 1902, 2d ser., vol. 8, sec. 4, No. 3, p. 102. '(Discussed.) Lingulepis Hall, Matthew, 1903, Geol. Survey Canada, Rept. Cambrian Rocks Cape Breton, p. 126. (Described and discussed. Hall's original description copied also.) Lingulepis Hall, Gbabau and Shimer, 1907, North American Index Fossils, vol. 1, p. 193. (Characterized.) Lingulella {Lingulepis) (Hall), Walcott, 1908, Smithsonian Misc. CoU.^ vol. 53, No. 4, PI. XI, and pp. 142 and 144. (Classification of subgenus.) Genotype. — Lingula acuminata Conrad. Schuchert states in his bibhography [1897, p. 258] that the only essential difference between Lingulepis and Lingulella is that the ventral beak of the former is often much attenuated. He does not refer to the interior markings of the valves, which have been illvistrated as of a pecuhar character by Hall [1892c, p. 60]. I quite agree with Schuchert, and I find that, with a fairly good series showing the interiors of both valves, all the essential markings of the vascular system and muscle scars are the sume as in Lingulella, except as the form of the ven- tral valve changes the outhne of the visceral area. When a shell of Lingulella (Lingulepis) acuminata (Conrad) (PL XLII, figs. Ig, Ih) is less attenuate than usual it is ahnost a good Lingulella, both as regards external form and interior markings. It is a fact, however, that many hundreds of specimens with a wide geographic distribution show a persistent form that is readily recognized, and for tlois reason, and also for convenience of classification, I give Lin- gulepis a subgeneric value. a The synonymy for this subgenus does not give a complete record of the various genera under which the species now included in Lingulepis were formerly placed; it gives only those references in which the genus is discussed or described. To complete the record the following mere generic references are hsted: Lingula Comad [1.S39, p. 64]. Lingula Emmons [1S42, p. 208]. Lingula Hall [1S47, pp. 3 and 9; 1S51, p. 204]. Lingula Owen [1S51, p. 170; 1852, p. 583]. Orbicuta Owen [1852, p. 583]. Lingula Emmons [1855, pp. 202 and 203]. Lingula Bilhngs [1856, p. 34]. Lingula ITall [18C2, pp. 21 and 435]. Lingula Hayden [1862, p. 73]. Lingula Billings [1863, p. 102]. Lingula Chapman [1863, p. 187]. Lingula Emmons [1863, p. 92]. Lingula Chapman [1864, p. 159]. Lingula HoU [18C5, p. 102]. Lingula Salter [1865, p. 102]. Lingula DaNndson [1866, pp. 41 and 53]. Lingula PhiUips [1871, p. 68]. Lingulepis Whitfield [1880, pp. 335 and 337; 1882, p. 169; 1884, p. 141]. Lingulepis Dwight [1880, p. 208]. Lingulella Matthew [1891, p. 146]. Glossina Tlall and Clarke [lS92a, PI. I, flgs. 10 and 11]. Lingula (^Glossina) Hall and Clarke [1892c, PI. I figs. 1 and 2]. Lingula James [1895, p. 884]. Lingulepis Matthew [lS9ob, pp. 256 and 257]. Lingulepis Walcott [lS97a, p. 404]. Lingulella Matthew [1899, p. 199]. Obolus (Lingulepis) Walcott [1901, p. 692]. Lingula Matley [1902, p. 141]. Oholus (Lingulella) Walcott [1902, p. 607]. Obolus (Lingulepis) Walcott [190.5a, p. 333; 1906, p. 567]. Lingulella (Lingulepis) Walcott [190Sd, p. 721. OBOLID^. 545 The visceral area of Oholus since (PI. XXVI, fig. 2ej is somewhat like that of Lingulella (Lingulepis) acuminata (PI. XLII, fig. Ig), and also resembles the visceral area of the ventral valve illustrated by HaU [1863, PL VI, fig. 15]. The condition of preservation and the original impress made by the different parts of the animal on the shell varies so much in shells of the same species that it is difficult, without a large series of specimens, to decide definitely upon generic or specific characters in the Obohdse. This is particularly true of Oholus, Lingulella, and Lingulepis. Of the 14 species and 2 varieties referred to Lingulepis from the Cambrian, 1 species occurs in the Lower Cambrian, 9 species and 2 varieties in the iliddle Cambrian, and 5 in the Upper Cambrian. One species, L. (L.) acuminata (Conrad), is common to the Mddle and Upper Cambrian and Ordovician. For the species that have been referred to Lingulepis and which are now referred to other genera, see pages 62-63. Lingulella (Lingulepis) acuminata (Conrad)."* Plate XXXIV, figures 3, 3a-e; Plate XL, figures 1, la-s; Plate XLI, figures 1, la-n; Plate XLII, figures 1, la-o. Lingula acuminata Conrad, 1839, Third Ann. Rept. New York State Survey, p. 64. (Described as a new species.) Limjula antiqua Emmons, 1842, Nat. Hist. New York, Geology, pt. 2, p. 268, fig. 68. (Occurrence discussed. Fig. 68 is copied in this monograph, PL XL, fig. la.) Lingula antiqua Emmons, Hall, 1847, Nat. Hist. New York, Paleontology, vol. 1, pp. 3-4, PL I, figs. 3a-e. (Described and discussed as a new species, but uses Emmons's name.) Lingula acuminata Conrad, Hall, 1847, idem, p. 9, figure with footnote. (Copies the original description of Conrad, 1839, p. 64. The figure is copied in this monograph, PL XL, fig. 1.) Lingula prima Owen, 1851, Proc. Am. Assoc. Adv. Sci. for 1851, p. 170. (Mentioned.) Lingula antiqvxi Emmons, Owen, 1851, idem, p. 170. (Mentioned.) Lingula antiquata Emmons, 1855, American Geology, vol. 1, pt. 2, pp. 202-203, PL IV, fig. 7. (Described and dis- cussed. Fig. 7 is copied from Emmons, 1842, fig. 68, p. 268.) Lingula acuminata Conrad, Emmons, 1855, idem, p. 203, PL IV, fig. 9. (Described. Ilg. 9 is copied from Hall, 1847, p. 9, footnote.) Lingula prima Owen, Billings, 1856, Canadian Naturalist, 1st ser., vol. 1, p. 34, fig. 1. (Described.) Lingula antiqua Emmons, Billings, 1856, idem, p. 34, fig. 2. (Characterized.) Lingula acuminata Conrad, Billings, 1863, Fifteenth Rept. GeoL Survey Canada, p. 102, figs.- 8a-g. (Mentioned.) Lingula acuminata Conrad, Chapman, 1863, Canadian Jom-. Ind., Sci. and Art, new ser., vol. 8, p. 187, fig. 155. (Men- tioned.) Lingula antiqua Emmons, 1863, Manual of Geology, 2d ed., p. 92, fig. 77. (Mentioned. Fig. 77 is copied from Emmons 1842, fig. 68, p. 268.) Lingula acuminata Conrad, Chapman, 1864, Minerals and Geology of Canada, p. 159, fig. 155. (Text and figure copied from Chapman, 1863, p. 187, fig. 155.) Lingulepis minima Whitfield, 1884, Bull. Am. Mus. Nat. Hist., vol. 1, No. 5, p. 141, PL XIV, figs. 1 and 2. (Described and discussed as a new species.) Lingulepis minima Whitfield, Dwight, 1886, Proc. Am. Assoc. Adv. Sci. for 1885, p. 208. (Mentioned.) Lingulepis acum.inata Conrad, Dwight, 1886, idem, p. 208. (Mentioned.) Lingula antiqua Emmons, James, 1895, Am. Naturalist, vol. 29, p. 884, fig. 1. (Mentioned. Fig. 1 is copied from Emmons, 1842, fig. 68, p. 268.) Lingulepis acuminata (Conrad), Matthew, 1895, Trans. Roy. Soc. Canada for 1894, 2d ser., vol. 1, sec. 4, No, 13 pp. 257-258, PL II, figs. 5a-b. (Described and discussed.) Lingulepis acuminata (Conrad), Schuchert, 1897, Bull. U. S. GeoL Survey No. 87, p. 259. (Discussed.) Lingulepis acuminata (Conrad), Walcott, 1897, Am. Jour. Sci., 4th ser., vol. 3, p. 404. (Merely changes generic and specific references.) Oholus (Lingulepis) acuminaius (Conrad), Walcott, 1899, Mon. U. S. GeoL Survey, vol. 32, pt. 2, p. 443. (Merely changes generic and specific references.) SjTionymy of the forms that have been referred to Lingulepis pinnaformis (Owen) from the Mississippi Valley, and which are now referred to Lingulella (Lingulepis) acuminata (Conrad) : Lingula prima Owen, Hall, 1851, Rept. Geology Lake Superior Land District, by Foster and Whitney, pt. 2, p. 204, PL XXIII, figs. la-g. (Described and discussed; dorsal valves.) a The synonymy for this species is given in two parts; first, the synonymy of the forms that have been referred to the species acuminata; second, the synonymy of the forms that have been referred to the species pimmformis. The latter species is now considered to be a synonym of the former. 62667°— VOL 51, pt 1—12 35 546 CAJVIBRIAN BRACHIOPODA. Lingula antiqua Emmons, Hall, 1851, Kept. Geology Lake Superior Land District, by Foster and Whitney, pt. 2, pp. 201-205, PI. XXIII, figs, 2a-<;. (Discussed; ventral valves.) Lingula pinnaformis Owen, 1852, Kept. Geol. Survey Wisconsin, Iowa, and Minnesota, p. 583, PI. I b, figs. 4, 6, and 8. (Described.) Lingula antiqua Emmons, Hall, 1862, Rept. Geol. Survey Wisconsin, vol. 1, fig. 2, p. 21. (No text reference.) Lingula pinmeformis Owen, Hall, 1862, idem, p. 435, fig. 3, p. 21. (Discussed.) Lingula antiqua Emmons, Haydbn, 1862, Am. Jour. Sci., 2d ser., vol. 33, p. 73, figs. la-b. (Discussed. It may be that the Lingula prima here mentioned by Hayden was based on the dorsal valves of L. antiqua.) Lingulepis pinnaformis (Owen), Hall (in part), 1863, Sixteenth Rept. New York State Cab. Nat. Hist., pp. 129- 130, PL VI, figs. 14-16 (not figs. 12 and 13, referred to Obolus matinalis). (Described and discussed.) Lingulepis pinnijormis (Owen), Meek and Hayden, 1865, Smithsonian Contrib. Knowl., No. 172, Paleontology Upper Missouri, pp. 2-3, PL I, figs. la-b. (Described and discussed.) Lingulepis dakotensis Meek and Hayden, 1865, idem, p. 3. (Name merely proposed in case the species should prove distinct.) Lingulepis pinnaformis (Owen), Hall (in part), 1867, Trans. Albany Inst., vol. 5, p. 107, PI. I, figs. 14-16 (not figs. 12 and 13, referred to Obolus matinalis). (Copy of Hall, 1863, p. 129-130.) Lingulepis pinnaformis (Owen), Whitfield, 1880, U. S. Geog. and Geol. Survey Rocky Mtn. Region, Rept. Geology and Resources Black Hills of Dakota, p. 335, PI. II, figs. 1-4. (Described.) Lingulepis dakotensis Meek and Hayden, Whitfield, 1880, idem, pp. 337-338, PL II, figs. 10 and 11. (Copies the description given by Meek and Hayden, 1865, p. 2, and discusses species. Figs. 10 and 11 are copied from Meek and Hayden, 18C5, PL I, figs, lb and la, respectively.) Lingulepis pinnaformis (Owen), Whitfield, 1882, Geology of Wisconsin, vol. 4, pp. 169-170, PL I, figs. 2 and 3. (De- scribed.) Lingulepis pinniformis (Owen), Dwight, 1886, Proc. Am. Assoc. Adv. Sci. for 1885, p. 208. (Mentioned.) Lingulepis pinniformis (Owen), Hall and Clarke, 1892, Eleventh Ann. Rept. State Geologist New York for 1891, figs. 237 and 238, p. 232; and PL I, figs. 16 and 17. (Mentioned. Figs. 237 and 238 are outline drawings of the figm-es given by Hall, 1863, PL VI, figs. 16 and 15, respectively; figs. 16 and 17 (PL I) are copied from Hall, 1863, PL VI, figs. 16 and 15, respectively.) Lingulepis pinniformis (Owen), Hall and Clarke, 1892, Forty-fifth Ann. Rept. New York State Museum for 1891, figs. 237 and 238, p. 548. (Mentioned. Figs. 237 and 238 are copied from those on p. 232 of the preceding reference.) Lingulepis pinniformis (Owen), Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, figs. 22 and 23, p. 60, and PL I, figs. 35 and 36. (Mentioned on pp. 60 and 61. Figs. 22 and 23 are outline drawings and figs. 35 and 36 are copies of the figures given by Hall, 1863, PL VI, figs. 16 and 15, respectively.) LAngulepis pinniformis (Owen), Schuchert, 1897, Bull. U. S. Geol. Survey No. 87, p. 260. (Questions specific reference.) LAngulepis pinniformis (Owen), Grabau and Shimee, 1907, North American Index Fossils, vol. 1, p. 193, fig. 227. (Described. The two figures in figm'e 227 are copied from Hall, 1863, PL VI, figs. 15 and 16.) Lingulepis prima (Hall), Grabau and Shimer, 1907, idem, p. 193. (Described, but no figures are given, and it is impossible to tell whether the species should be referred to Lingulella (Lingulepis) acuminata or to Lingulella ■prima.) General form elongate ovate, with the ventral valve subacuminate to acuminate, and the dorsal valve ovate in outline. The outline of the valves varies greatly (PL XL). On a single slab of rock from Whitehall, New York, there is a range of variation that unites the slender acuminate form, represented by figure Ic, with forms that are not to be differentiated from Lingulella acutangula (Roemer). The range of variation in the dorsal valve is less, but it varies from elongate ovate to nearly round ovate. The convexity of the valves varies with the size and condition of preservation. Those that preserve the natural convexity are rather strongly convex in the dorsal valve, and about one-third less so for the associated ventral valve. The variation in size is very marked, large groups of shells occurring where the average length of the ventral valve is not over 6 to 10 mm. In other localities this increases to 20 mm. with corresponding increase in width. Surface marked by concentric lines of growth, very fine concentric striae, and fine radi- ating strife. When the outer laj^er of the shell is exfoliated, the surface is marked by flattened, radiating striae and concentric lines and stride of growth. The iimer surface is marked by flat- tened radiating striae and minute pits or punctae. The shells from most localities are relatively thin, but some from the locality at St. Croix Falls show several layers, and those from the sandstones of the Black Hills of South OBOLID^. 547 Dakota are relatively strong and thick. The shell is built up of a thin outer layer and several inner layers or lamellae that, on the anterior and lateral portions of the shell, are oblique to the outer layer and form a thick, laminated shell very much like that of Oholus. Casts of the interior of the ventral valve show a clearly defined area that extends a considerable distance forward along the cardinal slopes. It is divided midway by a strong, rather broad pedicle furrow, and about midway of the very narrow side spaces, by extremely narrow flexure lines. One specimen from the Black Hills shows that the area formed a thin shelf between the pedicle groove and the lateral margins, the undercut extending some little distance beneath it. The area of the dorsal valve is clearly marked in a few specimens; it is relatively short although fairly well extended on the lateral margins. The cast of the visceral cavity (v) is rarely preserved except in its posterior portion; this is marked by the cast of a median groove, and the path of advance of the central, anterior lateral, and middle lateral muscle scars. Traces of the muscle scars or the anterior portion of the visceral cavity are rarely preserved; thus the heart-shaped pit so often seen in Lingu- lella and Oholus is outlined in not over a half dozen specimens out of several hundred casts of the interior. The position and shape of the visceral area varies with the width of the shell. In the long shells it extends far forward, while in the broad shells it scarcely reaches to the center (PI. XLII, figs, le and Ig.) No traces of a median septum have been observed in the ventral valve, but in the dorsal it is shown in the casts as a narrow, clearly defined, sharp depression, extending from between the anterior lateral scars back and between the central muscle scars. The muscle scars are more or less clearly shown in a number of casts of both valves. The lunbonal scar of the ventral valve is divided as in Oholus, the pedicle scar (m) (PI. XLII, fig. Ig) being situated between the two parts (gg). In the dorsal valve the umbonal scar is situated just in front of the area, arching slightly toward the beak. The scars of the central, anterior lateral, and middle lateral muscles are not clearly defined in the ventral valve, owing to their being crowded together in the space on each side of the anterior portion of the visceral cavity. The central muscle scars of the dorsal valve are of medium size and well defined on a number of casts of the interior of the shell. They are situated a little back of the center of the shell on each side of the median ridge, and their longer axis is slightly inclined outward. The anterior laterals are not well defined in the ventral valve, because they are crowded into a very narrow space. On the dorsal valve they are rarely visible, owing to their very faint impression on the shell. The transmedian scars are distinctly shoMTi on the dorsal valve, but in the ventral valve they have not been differentiated from the anterior laterals. The markings left on the shell by the vascular system are limited to the main or trunk sinuses on a few casts of the interior (PI. XLI, fig. la, and PI. XLII, fig. le). Ohservations. — The type specimens described by Conrad [1839, p. 64] were small, and frona an uncertain locality in the "Calciferous sandrock." His associate, Mr. Vanuxem, states [1842, p. 35] that Doctor Eights found a rolled stone containing L. acuminata, the surface of the fractured part showing from 60 to 70 valves in an area 2 by 3 inches. I have collected this species in situ. in great numbers in Saratoga County, and in the valley of the Hudson near Whitehall, in calcareous sandstones probably equivalent to Conrad's "Calciferous sandrock." The shell corresponds to the description given by Conrad, and occurs in great numbers in partings of the rocks. In all of the illustrations given of this species from New York, the small, relatively narrow form was figured. The broader and larger form that occurs in the compact, sandy limestone north of Saratoga Springs, and at Beverly, Ontario, does not appear to have been known to the earlier authors. It was not until 1863 that the Eastern forms so much like those of "Lingula pinnaformis" of Wisconsin were illustrated by Billings [1863, p. 102]. Matthew [1895b, PI. II] illustrated the interior of the ventral and dorsal valves of L. (L.) acuTninata from Beverly, Ontario. The muscle scars and their markings, as shown in Matthew's diagrammatic figures, vary from those 548 CAJVIBRIAN BRACHIOPODA. I have observed, and none of the specimens studied by him showed the area of either the ventral or dorsal valve. As the result of a comparison of a series of specimens of L. {L.) acuminata from the Potsdam sandstone and the base of the " Calcif erous " in Saratoga, Washington, Franklin, and Jsfferson counties. New York, and from the same horizon in Ontario, Canada, with a large series of specimens from the "St. Croix sandstone" of Wisconsin, I was led [1897a, p. 404] to conclude that "Lingula ■pinnaformis" Owen was a synonym of Lingulella {Lingulcpis) acuminata (Con- rad), thus making L. (L.) acuminata the type of the subgenus Lingulepis, the original description of the subgenus being based upon specimens from the "St. Croix sandstone" of Wisconsin. It is hardly practicable to illustrate all of the varieties of L. (L.) acuminata (Conrad) as they occur in widely distributed localities. The shells appear to have varied in size, thickness, convexity, and outline at various localities, and often in the same locality in different layers, probably owing to the character of food supply and the vitality of the individual animals. Very fine specimens of the casts of young shells of the narrow, elongate form occur at Mount Washington, Eau Claire, Wisconsin. The species ranges from western Vermont, New York, and eastern Canada, westward across the upper Mississippi Valley to the Black HiUs of South Dalcota, the Bighorn Mountains of Wyoming, and the Rocky Mountains of central Colorado. In the Appalachian region it ranges southward to Tennessee and Alabama, and westward to the Arbuckle and Wichita mountains of Oklahoma, and the Franklin Range near El Paso, Texas. Its vertical range appears to have been from the upper portion of the Middle Cambrian in the Mississippi Valley and the Black HiUs to the lower layers of the "Calciferous " of the Ordovician in New York and Canada. A number of shells from the Upper Cambrian rocks of Nevada conae within the rather wide range of variation of this species. I was at first inclined to place them as a variety, but after extended comparison with a series of specimens from New York and Wisconsin, decided that nothing would be gained by so doing. A few figures on Plate XXXIV, figures 4, 4a-e, illus- trate the wide variation in form of the Nevada shell, a variation comparable with that from the typical locality in New York'. A fine series of specimens illustrating the narrow and broad forms has been collected from the limestone in the upper portion of the Reagan sandstone (Upper Cambrian), at the north- west extremity of the Arbuckle Mountains, Oklahoma. Dwight [1886, p. 208], in speaking of the Upper Cambrian fauna near Poughkeepsie, New York, said: It will be observed, as has been suggested to me by Whitfield, that the fauna of this locality forms a connecting link between the Potsdam fossils of the Appalachian region and that of the more western States. Thus, the Lingulella pinnaformis of Wisconsin and other western localities is here mingled with Lingulepis minima and acuminata of New York State. Dwight's remark that the species "Lingulella pinnaformis" occurs mingled with "Lingu- lepis minima" and "L. acuminata" proves that all the varieties of Lingulella (Lingulepis) acuminata occur at the Dutchess County locality. Formation and locality. — Ordovician and TJpper Cambrian : (338u) Strata from the upper layers of the Potsdam sandstone to the lower portion of the "Calciferous sandrock" at Chateaugay Falls, Franklin County, New York. TTpper Cambrian: (392e [Billings, 1856, p. 34]) Sandstone on lot 22, ninth concession, township of Bastard; (392d [Billings, 1856, p. 34]) sandstone on lot 11, eleventh concession, township of Lansdowne; and (392b [Matthew, 1895b, p. 258]) sandstone (corresponding to the passage beds above the massive Potsdam sandstone at Chateaugay Falls) at Beverly, township of Bastard; all in the county of Leeds, Ontario, Canada. (392) Potsdam sandstone at Burgei3s;.(.392m) sandstone on the east shore of Missisquoi Bay, 1.5 miles (2.4 km.) south of Phillipsburgh, Province of Quebec; and (392n) sandstone in eastern Canada (exact locality unknown); all in Canada. (16n) Interformational conglomerates and shales in Adams pasture, 0.5 mile (0.8 km.) west of Main Street, on Lake Street, St. Albans, Franklin County, Vermont. (76) Arenaceous limestone at Hoyt's quarry, 4 miles (6.4 km.) west of Saratoga Springs, Saratoga County; (76a) arenaceous limestone in a raihoad quarry 1 mile (1.6 km.) north of Saratoga Springs, Saratoga County; (109) sandstone 25 feet (7.6 m.) above the Archean, 1.5 miles (2.4 km.) south of Deweys Bridge, on the Champlain Canal, Washington OBOLIDJ^:. 549 County; (367k) sandstone at Deweys Bridge, Washington County; (110 and 110a) shaly calcareous sandstone resting on massive layers of Potsdam sandstone, east side of the town of WTiitehall, Washington County; (338r [Billings, 1856, p. 34]) Potsdam sandstone at Keeseville, Essex County; (338s [Emmons, 1842, pp. 267 and 26S]) Potsdam sand- stone at High Bridge, on Ausable River, Essex County; (77) sandstone at several horizons in the section below the falls at the high bridge, in Ausable Chasm, Essex County; (111) at the top of the Potsdam sandstone on Marble River, 1 mile (1.6 km.) south of Chateaugay, FrankUn County; (338t) Potsdam sandstone in Ausable Chasm, below Keeseville, Essex County; (338w [Hall, 1847, p. 4]) Potsdam sandstone at Hammond, St. Lawrence County; (338j [Hall, 1847, p. 4]) Potsdam sandstone near Alexandria Bay, Jefferson County; (185) sandy layers above the massive Potsdam sandstone one-half mile (0.8 km.) southeast of Redwood, Jefferson County; (185a) sandy layers 20 feet above the massive Potsdam sandstone, east side of Indian View, 3 miles (4.8 km.) south of Theresa, Jefferson County; (367j) sandstone 3 miles (4.8 km.) south of Poughkeepsie, Dutchess County; (108) sandstone 1 mile (1.6 kin.) south of Poughkeepsie, Dutchess County; and (367e [Dwight, 1886, p. 205]) shaly limestones 850 feet (259.1 m.) southerly from the southwest corner of the driving park and 2,200 feet (670.6 m.) west of the road leading southerly from the same, about 1 mile (1.6 km.) southwest of Vassar College, near Poughkeepsie, Dutchess County; all in New York. (92b) Limestone on Buffalo Creek, 2 miles (3.2 km.) southeast of Buffalo Mills, Rockbridge County, Virginia.. (105) Limestone in Knox dolomite, at Bishops ilill, Hancock County; and (107o) limestones and shales at the base of the Knox dolomite, west of the top of Copper Ridge, near the Southern Railway cut, about 10 miles (16.1 km.) northwest of Knoxville [Keith 1896b, areal geology sheet], Knox County; both in Tennessee. (79 and 79b) "St. Croix sandstone" near Hudson, St. Croix County; (82 and 82s) "St. Croix sandstone" on the bank of St. Croix River, St. Croix Falls, Polk County; (328h) silicocalcareous layers of Fib of Owen, at the falls of the St. Croix, Polk County; (97a) "St. Croix sandstone" near Winfield, Jefferson County; (98) "St. Croix sand- stone" near Eau Claire, Eau Claire Coimty; and (99a) "St. Croix sandstone" near Pilot Knob, Adams County; all in Wisconsin. (330 [Hall, 1851, p. 204]) Sandstone on Taquamenon Bay, Chippewa County; (330b) sandstone at Iron Mountain, Dickinson County; and (330a [Hall, 1851, p. 204]) sandstone on Escanaba River; all in northern Michigan. (33911 [Hall, 1863, p. 130]) "St. Croix sandstone " near the mouth of the Minneiska (Miniska) River, near the line between Wabasha and Winona counties; and (97b) "St. Croix sandstone" below the greensand bed and about 25 feet above St. Croix River at Franconia, Chisago County; both in ilinnesota. (353b) Sandstone just beneath the Ophileta zone, south end of the Franklin Range, El Paso County, Texas. (360g) Shaly sandstone on Trout Creek, 1 mile (1.6 km.) below Manitou Park, El Paso County, Colorado. (54d) About 1,050 feet (320 m.) above the Middle Cambrian and 175 feet (53.3 m.) below the top of the Upper Cambrian in the lower part of the limestone forming 1 of the St. Chai-les formation [Walcott, 1908f, p. 192]; and (54g) just above the Middle Cambrian, near the base of the bedded light-gray sandstone forming 4 of the St. Charles for- mation [Walcott, 1908f, p. 193]; both in Blacksmith Fork Canyon about 10 miles (16.1 km.) east of Hyrum, Cache County, I'tah. (7x and 7y) Limestone of the Emigrant formation [Turner, 1902, p. 265], about 2.5 miles (4 km.) southeast of Emigrant Pass; and (7z) limestone of the Emigrant formation [Turner, 1902, p. 265], about 3 miles (4.8 km.) southeast of Emigrant Pass; both in the Silver Peak quadrangle (LT. S. Geol. Survey), Esmeralda County, Nevada. (9q) About 10 feet (3 m.) above the porphyry contact and 90 feet (27.4 m.) below the Arbuckle limestone in limestone of the Reagan sandstone, middle of west half of sec. 2, T. 4 N., R. 13 W., about 15 miles (24.2 km.) north- west of Fort Sill, Comanche County; (9s) about 85 feet (26 m.) below the Arbuckle limestone in the limestone of the Reagan sandstone, near middle of west half of sec. 13, T. 4 N., R. 13 W., 13 miles (20.8 km.) northwest of Fort Sill, Comanche County; (9v) limestone of the Reagan sandstone, about 250 feet (76 m.) below the Ai-buckle limestone SW. \ sec. 17, T. 4 N., R. 12 W., about 11 miles (17.7 km.) northwest of Fort Sill, Comanche County; (12n) lime- stone of the Reagan sandstone (in the section 7 miles (11.2 km.) north of Springer this horizon is about 240 feet (73 m.) above the porphyry contact and 40 feet (12 m.) below the Arbuckle limestone), NW. J sec. 1, T. 2 S., R. 1 E., Ardmore quadrangle (U. S. Geol. Survey), Carter County; and (12p) about 225 feet (69 m.) above the igneous rocks in the limestone of the Reagan sandstone, at the northwest extremity of the Arbuckle Mountains, about 4 miles (6.4 km.) east of Homer, Carter County; all in Oklahoma. (14b) Limestone on Cold Creek at north end of gorge opposite the north end of Sponge Mountain, 2 miles (3.2 km.) south of the San Saba County line in Llano County; (14r) sandstone in the lower part of the beds exposed on Colorado River, 3 miles (4.8 km.) south of the northeast corner of Llano County; (69) limestone near Honey Creek, Burnet County; and (70) limestone near Morgans Creek, Burnet County; all in Texas. Middle Cambrian : (328e) "St. Croix sandstone" at St. Croix Falls, Polk County; and (79x) "St. Croix sand- stone" near the flour mill on Beaver. Creek, north of Galesville, Trempealeau County; both in Wisconsin. (84) "St. Croix sandstone" at Dresbach, opposite the mouth of Black River, Winona County; (84s) "St. Croix sandstone" near Dakota, Winona County; (339j) sandstone between the lowest blue shale and the reddish calcareous beds above, at Taylors Falls, Chisago County; and (339k) sandstone near Winona, Winona County; all in Minnesota. (89) Limestone in Mm-phi-ees Valley, Blount County, Alabama. (374d) Shale 2 miles (3.2 km.) north of Rotherwood; and (124a) shale (Nolichucky?) overlj-ing the hmestone which rests on the Rogersville shale, on Big Creek, southeast of Harlan Knob, 4 miles (6.4 km.) northeast of Rogere- ville [Keith, 1905, p. 4, and areal geology sheet]; both in Hawkins County, Tennessee. 550 CAJMBRIAN BRACHIOPODA. (355) Sandstones on Red Canyon Creek, southwest side of Black Hills; (365d) sandstone in the Black Hills; (164) sandstone in the Deadwood formation in the cliffs on the east side of the valley near Deadwood, Black Hills; (167) sandstone beneath limestone and resting on the pre-Cambrian in a bluff 9 miles (14.4 km.) west of Custer, Black Hills; and (355b) sandstone in the Deadwood formation on Castle Creek, west side of Black Hills; all in South Dakota. (171 and 171a) Sandstone in Big Goose Creek Canyon, Bighorn Mountains, west of Sheridan, Sheridan County; (302m) middle of shale above lower sandstone on Billy Creek, in the Bighorn Mountains, Sheridan County; and (340c) dai'k-red sandstone near the base of the Cambrian at Rawlins, Carbon County; all in Wyoming. IjINGUlella (Lingulepis) acuminata meeki (Walcott). Plate XLI, figures 2, 2a. Lingulepis meeki Walcoit, 1897, Am. Jour. Sci., 4th ser., vol. 3, p. 40.5. (Described and discussed as below as a new species.) Oboliis {Lingulepis) acuminatus meeki Walcott, 1899, Mon. U. S. Geol. Survey, vol. 32, pt. 2, p. 444, PL LX, figs. 1 and la. (Text copied from preceding reference. The specimens represented by figs. 1 and la are redrawn in this monograph, PI. XLI, figs. 2 and 2a, respectively.) Obolus (Lingulepis) acuminata weeksi Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 333. (Merely used for Oholus {Lingulepis) acuminata meeki by mistake in discussion of " Obolus {Lingulepis) eros.") Shell small, attenuate, marked b}^ rather strong concentric Imes and stcim of growth, and interrupted, irregular, radiating striae. Ventral valve narrow, elongate, beak acuminate, rostral slopes long, nearly straight, passing gradually mto the curvature of the anterolateral margins, and posteriorh'- meeting at a very acute angle; front strongly rounded. Length of valve, 8 mm.; width, 3.5 mm., the widest portion being near the anterior extremity. Beak slight^ upcurved, the longitudinal median line straight or even slightly concave from the apex of the beak to the middle, where it begins to slope gently to the frontal margin; transverse curvature very slight anteriorly, more convex than the beak. Dorsal valve more convex than the ventral, linguliform; beak depressed, bluntly rounded, curving evenly and gradually to the semitruncate anterior margin. Observations. — The interior markings of this shell have not been ascertained, but the external characters are such as to make a reference to the subgenus Lingulepis more than .probably correct. The flat, acute-acuminate ventral valve with its elevated or retrorse beak, which is not covered by the smaller dorsal valve, is characteristic of Lingulepis. There is a form from Texas, probably identical with Lingulella perattenuata O^Tiitfield) that might be mistaken for this variet}^, but it is an undoubted Lingulella and does not show the external characteristics of lAngulepis. A comparison of Lingulella (Lingulepis) acuminata meeki with the young and narrow specimens of L. (L.) acuminata (Conrad) shows it to vary from that species, the posterior rostral .slopes of X. (i.) acuminata possessing a peculiar incurv- ing which is not shown in L. (L.) acuminata meeM. After the publication of "LAngulepis meeJci'' [Walcott, 1897, p. 405] shells were collected from the north end of the Teton Range, which showed that that form was very closely related to L. (L.) acuminata. As all the Teton Range shells were quite small and the majority had the characters of "Lingulepis meelci," the latter was reduced to a variety of Z. (L.) acuminata [Walcott, 1899, PI. TjX, figs. 1 and la], and the Teton shells were included with those from the Gallatin Range. The varietal name was given in honor of Dr. F. B. Meek. Formation and locality. — Middle Cambrian : (302b) Limestones near Crowfoot Ridge, Gallatin quadrangle { U. S. Geol. Survey), Yellowstone National Park; and (4e) limestones about 950 feet (289.6 m.) above the unconformable base of the Cambrian in the divide at the head of Jackson Creek (locally known as Sheep Creek), a creek flowing into Jackson Lake about 0.5 mile (0.8 km.) south of its northwest corner, Teton Mountains, Grand Teton quadrangle (U. S. Geol. Survey), Uinta County; both in Wyoming. (4h) About 375 feet (114.3 m.) above the base of the Cambrian in limestone interbedded in the Flathead shales of Peale [1893, p. 21], 1 mile (1.6 km.) north of the junction of East Gallatin and West Gallatin (Gallatin) rivers, 4 miles (6.4 km.) east-northeast of Logan, Threeforks quadrangle (U. S. Geol. Survey), Gallatin County, Montana. OBOLIDiE. 551 LiNGTJLELLA (LiNGTJLEPIs) ACUMINATA SEQUENS Walcott. Text figures 46A-B. Glossina acuminata Hall and Clarke [not Conrad], 1892, Eleventh Ann. Kept. State Geologist New York for 1891, PL I, figs. 10 and 11. (No text reference.) Lingula (Glossina) acuminata Hall and Clarke [not (Conrad)], 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, PL I, figs. 1 and 2. (No text reference. Figs. 1 and 2 are copied from Hall and Clarke, 1892a, PL I, figs. 10 and 11, respectfully.) Lingulella (Lingulepis) acuminata sequensWAi^coTT, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, p. 72, PL YIII, fig. 4. (Characterized and discussed as a new variety. Fig. 4 is copied in this monograph as fig. 46A.) This variety differs from LinguleUa (Lingulepis) acuminata (Conrad) in being somewhat less attenuate in its ventral valve, and in having the cardinal slope of the ventral valve straight, instead of gently incurved. It occurs at a sUghtly higher geologic horizon than L. (L.) acuminata, and appears to be a form derived from that species. Judging from Hall and Clarke's illustrations [1892a, PL I, figs. 10 and 11] they had rep- resentatives of this variety of LinguleUa (Lingulepis) acuminata and mistook them for the form illustrated by Hall [1847, p. 9] as Lingula acuminata. That figure represents a typical form of L. (L.) acuminata, and is not the variety illustrated by Hall and Clarke in 1892. The specimens illustrated by Hall and Clarke are given as from Saratoga County, New York, "Calciferous sandstone." The specimens wliich I have taken as typical of this variety are from Division A of the Beekmantown limestone. This form owes its varietal name to the fact that it is a later representative of the species. ■"■ B Figuhe 46. — LiTigulella (^Lingulepis) acumi- FoRMATiON AND LOCALITY. — Ordovlcian: (367c) Beekmantown limestone, 7m(o sejitcns Waleott. A, Ventral valve Division A; quarry near the northwest suburb of Ticonderoga, Essex County, showing nearly straight lateral slopes IMew XorK. T>0Tsa\ valve (U. S. Nat. Mus. Cat. No. Lingulella (Lingulepis) eros (Walcott). 53075b). The specimens represented are from Lo- Plate XXXIX, figures 9 and 9a. cality 367o near Ticonderoga, New York. Fig. 46A is copied from Walcott [1908d, PI. Obolu^ (Lingulepis) eros Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 333. VIII, fig. 4]. It represents the type speci- (Described and discussed as below as a new species.) m™- Ventral valve elongate with rostral slopes gradually converging so as to form an acuminate beak. Surface marked by fine concentric lines of growth and very fine, somewhat irregular, concentric striae. Rather large scattered punctse occur on the interior surface. This species is represented by fragments and two broken ventral valves; these indicate a length for the ventral valve of from 7 to 10 mm. It is allied to Lingulella (Lingulepis) acumi- nata meeJci ° (Walcott) of the Middle Cambrian fauna of the Teton mountains of Wyoming. Formation and locality. — Middle Cambrian: (C7) Lower limestone member of the Kiulung group [Black- welder, 1907a, pp. 37 and 39 (last list of fossils), and fig. 8a (bed 33), p. 29], 2.2 miles (3.5 km.) southwest of Yenchuang, Sintai district, Shantung, China. LiNGUELLA (Lingulepis) exigua (Matthew). Plate XXXIII, figures 4, 4a; Plate XLIII, figures 1, la-z. Obolus (Lingulepis) gregwa Walcott (in part) [not (Matthew)], 1901, Proc. U. S. Nat. Mus., vol. 23, pp. 692-694. (Described and discussed almost as on pp. 552-553, with the exception of the notes under "Observations," which have been rewritten in this monograph. The following species were included in this reference: Lingu- lella (Lingulepis) exigua, L. (L.) gregwa, Lingulella tumida, and L. atava.) a Written " weekai" in the original description [Walcott, 1905a, p. 333] through mistake. 552 CM'IBRIAN BEACHIOPODA. Lmgulepis starri var. Matthew, 1903, Geol. Survey Canada, Rept. Cambrian Rocks Cape Breton, pp. 193-197, PI. XIV, figs. 2a-c. (Gives an essential copy (rearranged) of the description given by Walcott, 1901, pp. 692-694, and describes and discusses the specimens referred by Walcott to Obolus {Lingulepis) gregwa as belonging to an undetermined variety of Matthew's "Lingulepis starri.") Lingulepis starri exigua Matthew, 1903, idem, pp. 197-198, PL XIV, figs. 3a-d. (Described and discussed as a new variety.) General form elongate ovate with the ventral valve acuminate and the dorsal valve ovate triangular in outline. The outline of the valves varies, as showii by the series of figures on Plate XLIII and by many other specimens not illustrated. The convexity of the valves varies with the condition of the preservation, those from the sandstone being rather stroiagly convex, wliile those in the shale are very much compressed. On the dorsal valve of the youngest shells there is a marked and rather broad, shallow sinus extending from the umbo to the front where it flattens out. One of the largest ventral valves has a length of 21 mm., with a width of 18 mm. A dorsal valve 16 mm. in ■width has the same length; other examples are a little wider than long. Surface of the shell marked by concentric striae and undulations of growth, over wliich there is a series of very fine, elevated, sharply undulating and inosculating lines that form a minute irregular network over the surface, very much like that of Lingulella {Lingulepis) gregwa (Matthew), except that the irregular lines are very much finer on the latter. Where the Imes are strongly elevated the effect is that of a minutely granulose surface. ' In some examples the surface suggests an incrusting or scabrous outer layer of shell covered mth minute points. When the thin outer layer of the shell is exfoliated the surface of the various bright, sluny, inner layers is nunutely granulose, in addition to the flattened, radiating strise and concentric lines of growth. The interior surface of both valves is often marked by con- centric rows of strong pits or punctse very much as in Lingulella davisi (McCoy) (PI. XXXI, fig. 6g). In some specimens the lines of punctse extend over the surface of the visceral cavity so as to obscure the vascular markings and muscle scars. In some examples only a few scat- tered punctse occur, wliile in others they are present over nearly the entire surface. The small shells are tliin, but the larger ones are built up of a very tloin outer layer and several inner layers or lamellse that are more or less obhque to the outer surface, especially over the anterior and lateral portions of the shell. The plane of the cardinal area of the ventral valve is nearly coincident, near its edges, with the edge of the shell. The area is long and extends well forward on the cardinal slope. It is divided midway by a narrow, rounded, deep pedicle furrow, and about half way between the pedicle furrow and the lateral margins by an unusually well-defined flexure fine wliich is in fine with the main vascular furrows of the interior of the valves ; fine striae of growth cross the area and arch around the pedicle furrow parallel to the base of the area. There is practically no undercut beneath the area except near the flexure line at the frontal margin of the area. The area of the dorsal valve is short, narrow, and crossed by fine lines of growth parallel to its base. The cast of the visceral cavity in the ventral valve shows it to have been relatively small and usually confined to the posterior half of the shell, although in some shells it extends past the center (PI. XLIII, fig. Iq). There are no traces of a median septum in the ventral valve; in the dorsal valve, at the bottom of the groove between the central muscle scars, there is a shghtly elevated median hne that extends forward to the anterior margin of the visceral cavity beyond the anterior lateral muscle scars. The visceral cavity of the dorsal valve usually extends forward to about the center of the valve, but in a series of specimens coUected in 1903 a number of interior casts show the front of the visceral area varying in position from back of the center to nearly the frontal margin of the shell ; it varies in width and outline very much as the shells vary, being wide in broad shells and narrow in elongate forms. The markings left on the shell by the vascular system are very strong and beautifully pre- served in some portions. The direction and size of the main sinuses are well shown by the illustrations ; in some shells there is a double groove with a slight ridge between ; in others the OBOLID^. 553 ridge is large, only a trace of an outer groove remaining; in some J^oung shells the groove is broad and shallow; in all shells the large size of the main vessels is shown by the broad, strong grooves or ridges left on, the shell. It frequently happens tliat the lines of sharply defined pits on the Unes of growth deeply mdent the grooves and rounded ridges left by the main vessels and mark them off iato sections. The interior and lateral vessels left narrow but strong grooves or ridges on the shell, which, however, are usually obscured by the strong pittmg of the surface. The parietal scar surrounds the visceral cavity in each valve, crosses the course of the main vascular vessels, and comes back around the spaces occupied by the muscle scars, terminating at the edge of the area at the flexure line in the ventral valve; termination unknown on the dorsal valve. Some of the muscle scars are finely shown in the dorsal valve and fairly well in the ventral. The umbonal scar of the ventral valve is divided, the pedicle scar being situated between the two parts. In the dorsal valve the umbonal scar is close to the area, and extends nearly as far each side of the median line as the length of the area. The scars of the central muscles in the ventral valve are crowded in with the middle and outside laterals withui the trapezoidal space (c, PL XLIII, figs. Ic^ and Is). In the dorsal valve they are located on a low ridge each side of a central, longitudinal median depression; they are elongate oval in outlme, their major axis bemg subparaUel to the median line of the shell; fine longitudinal lines cross the scars in the best preserved specimens; the ridge on wliich the central scars occur varies m strength, but it appears to be present in all adult shells; it narrows gradually posteriorly and rather rapidly to the inner side of the anterior lateral muscle scars. The anterior laterals of the ventral valve are placed well back on the narrow space between the edge of the area and the maua vascular sinus; they are elongate and rather large; in the dorsal valve they are elongate ^^-ith the major axis inclining toward the median line (PL XLIII, figs. Ir and ly). The middle and outside laterals are situated in the trapezoidal area (c) of the ventral valve, but neither is clearly separable fi-om the other or from the central scars. In the dorsal valve the position of the middle and outside laterals is shown, but not their form or size. The transmedian scars in the ventral valve are seen just back of the anterior laterals, but they have not been observed in the dorsal valve owing to the imperfections of the shell. Oiservations. — This is one of the most interesting species of lAngulepis I have known. In its coarsely pitted inner surface it recalls LinguleUa davisi (McCoy) (PL XXXI) of England, and Oholus willisi (Walcott) (PL XXIII) of the southern Appalachians. The elongate ventral valve is hke that of LinguleUa (Lingulepis) acuminata (Conrad), whUe the interior scars and markings are those of Oholus. With L. (L.) gregwa (Matthew) and L. (i.) starri (Matthew) it is the Atlantic coast representative of L. (L.) acuminata which is so abundant in the Middle Cambrian of the Upper Mssissippi Valley, and in the passage beds between the Cambrian and the Ordovician in the region adjoining the Adirondack Mountains of New York. It differs from L. (L.) acuminata in its surface characters. The slieUs embedded in the fine-grained shales are all flattened and more or less distorted by compression, while those in the sandy layers interbedded in the shales retain their original convexity, although frequently distorted and fractured by movement of the matrix. The fracturing of the brittle, mineralized shell is beautifidly illustrated by Plate XXXIII, figure 4a, which represents the sUiceous fillings of the fractures, the shell substance having been dissolved with acid. Typical specimens of LinguleUa (Lingulepis) exigua have narrow, elongate ventral valves and broadly oval dorsal valves. I was at first strongly inchned to separate the broad, thick shells as a distinct species, but on findmg a series of connecting forms and observing that the surface and interior markings were similar, I decided to unite them. The shells varj^ materially in their external aspect in the different layers of siliceous rock, but when the shell substance is removed by acid it is found that their interior and exterior characters are the same. The typical forms of L. (L.) exigua are represented in Plate XLIII, by figures 1, la-b. Id, Ig-j, and the variations 554 CAJVIBRIAN BRACHIOPODA. by figures If, lo-s. With growtli in size and age the shell increases in thickness notably over the posterior portions. In some notes [1901, p. 692] on "Lingulepis gregwa" (Matthew), I identified this shell as "Oholus {Lingulepis) gregwa." It is closely related to it but differs in the surface characters. The exterior shell of LinguleUa (Lingitlepis) gregwa is marked by fine, ii-regular, elevated, and sometimes inosculating ridges that have a row of minute tubercles on them that give a beaded appearance to each ridge. The surface of the shell of L. (L.) exigua has a much more minutely granulose surface formed by verj^ irregular, inosculating, elevated lines or ridges, much like that of L. (L.) roherti (Matthew). Matthew [1903, p. 193] refers this form to "Lingulepis starri var." With the types of starri as a basis of comparison I find that the type of surface of starri is as stated by Matthew [1891, p. 147]: "Each valve is ornamented by. numerous, concentric furrows, closely set, about 12 to 15 to a millimeter." I find 8 to 10 on one of the typical specimens. This surface is quite unlike the surface of L. (L.) exigua which is as described above. Wlien the thin outer layer is exfoliated the concentric strise and ridges of growth are Hke the surface of starri, but the outer' surface is roughened ("granulated," Matthew) in a manner unlike the surface of L. (L.) exigua. It has the appearance under a strong magnifier of a surface produced by fine points distributed over an incrusting layer of shell. Formation and locality. — Upper Cambrian: (3n) Thin-bedded sandstone on Salmon River, Gillia Hill, 13 miles (20.9 km.) south of Marion Bridge, eastern Cape Breton, Nova Scotia. Middle Cambrian: (3i) Compact, fine-grained, thin-bedded, gray sandstone of the Paradoxides zone [horizon of Division Cib, ilaUhew, 1903, p. 195], on McLean BrooJc, 1 mile {1.6 km.) east of McCodrum Brooh and 1.5 miles {2.4 Jem.) west of Marion Bridge; (10s and lOt) sandstone on McLean Brook, near Marion Bridge; (307f [Matthew, 1903, p. 198]) shale of Division C2a on McLean Brook, Mu-a River; (307g [Matthew, 1903, pp. 195 and 198]) shales of Division C2b on McLean Brook, Mira River; (13r) sandstone of the " Johannian" Division of Matthew's section on Gillis Brook, East Bay, east of Bras d'Or Lake; and (llz) sandstone on Big Ridge, 2 miles (3.2 km.) south of Marion Bridge, on the canal of John McDougald; all in eastern Cape Breton, Nova Scotia. LlNGULELLA (LlNGULEPIS) GREGWA (MattllCw). Plate XLIV, figures 1, la-p. Lingulella gregwa Matthew, 1899, Bull. Nat. Hist. Soc. New Brunswick, vol. 4, pp. 199-200, PI. 1, figs. la-f. (De- scribed and discussed as a new species.) Obohis {Lingulepis) gregwa Walcott (in part), 1901, Proc. U. S. Nat. Mus., vol. 23, pp. 692-694. (The following species were included under Lingulella {Lingulepis) gregwa in this reference; Lingulella {Lingulepis) exigua, L. {L.) gregwa, Lingulella tumida, and L. atava. The specimens upon which the description was based are now referred to Lingulella {Lingulepis) exigua. Lingulepis gregwa Matthew, 1903, Gaol. Survey Canada, Rept. Cambrian Rocks Cape Breton, pp. 56-57. (Notes on orientation of shells.) Lingulepis gregwa Matthew, 1903, idem, pp. 126-131, PI. IX, figs. 3a-f. (Described and discussed. Figs. 3a-f are copied from Matthew, 1899, PL I, figs, la-f.) The description of LinguleUa {Lingulepis) exigua (Matthew) applies very closely to this species, with the exception of the surface characters and details of outline, and the interior markings of the valves. As a whole, the ventral valve of L. (L.) gregwa is less acuminate, and the outline of the dorsal valve is more rounded posteriorly. A comparison of the series of illustrations of the two species fully exliibits the differences referred to. The exterior sur- face of the shell of L. (L.) gregwa is marked by a few, strong, concentric lines of growth, and numerous fine, concentric, irregular, often inosculating ridges having a row of minute tubercles on them that gives a beaded appearance to each ridge. This appearance is unmistakable when the outer shell is at all well preserved. There are also indications of very fine radiating ridges, irregularly dispersed over the surface of the shell. When the thin, highly ornamented outer layer is exfoliated the various lamellae of the shell show very fine, radiating striae, and a few concentric lines of growth. The interior of the shell has rather large scattered punctae, and occasionally a specimen shows the punctae gathered in concentric lines. The shell is built up of a thin outer layer and several inner la3''ers, or lameUse, that are more or less oblique to the OBOLID^. 555 outer surface, especially over the anterior and lateral portions of the shell, where they are much more numerous. In many specimens the shell substance has been replaced by calcite. Interiors of the ventral valve show considerable difference in the position of the main vascular sinuses. They are usually well out toward the sides. In the dorsal valve the main vascular sinuses are widely separated, and the visceral area is well extended toward the front. Qhservations. — When studying the collections made by S. Ward Loper on McLean Brook in 1900, 1 identified the shells now placed xinder Lingulella (Lingulepis) exigua as " Obolus (Lin- gulepis) gregwa." But at that time I had only the somewhat imperfect material in Matthew's collection from Dugald Brook for the purposes of comparison. With a large series of well- preserved specimens collected on Dugald Brook in 1901 by Loper, the fact that the two species had been confused became at once apparent. Lingulella {Lingulepis) gregwa is found in great numbers at a lower stratigraphic horizon beneath the Paradoxides zone, while L. (L.) exigua occurs at the summit of the Middle Cambrian fauna in association with Paradoxides. Both species have strong points of resemblance to L. (L.) acuminata (Conrad) and both, in their younger stages, depart to such an extent from the typical forms of the adult shell that they might be considered a distinct species if found at another locality or stratigraphic horizon. The specific name is derived from Gregwa Brook, on wliich specimens of the species occur. Formation and locality. — Middle Cambrian: (lOp) Sandstone just below the waterfall in Division E2b of Matthew's [1903, p. 21] Etcheminian, on Dugald Brook, Indian River; (lOp') sandstone one-fourth mile (0.4 km.) from lower bridge, on Gregwa Brook, Indian River; (lOp") sandstone on the small brook on the hill between the bridge over Indian River and McPhees Brook; (13t") sandstones of Divisions Elc and Eld of Matthew's [1903, p. 21] Etcheminian, on Dugald Brook, Indian River; (344e [Matthew, 1903, p. 78]) shales of Division Eld of Matthew's [1^03, pp. 28 and 29] Etcheminian, on Boundary Brook, eastern side of the Escasonie Indian Reservation; (344k » [Matthew, 1903, p. 77]) sandstones of Division Elb of Matthew's [1903, p. 21] Etcheminian, on Dugald Brook, Indian River; (344m [Matthew, 1903, p. 78]) sandy shales of Division Eld of Matthew's [1903, p. 31] Etcheminian, on Dugald Brook, Indian River; and (344n [Matthew, 1903, p. 33]) shales in the gorge at the old mill on McCodrum Brook, Mira River; all in eastern Cape Breton, Nova Scotia. LiNGXJLELLA (LlNGULEPIs) GREGWA EOBUSTA (Matthew). Lingulepis gregwa rohusta Matthew, 1903, Geol. Survey Canada, Rept. Cambrian Rocks Cape Breton, p. 57. (Notes on orientation of shells.) Lingulepis gregwa robusta Matthew, 1903, idem, p. 131. (Characterized as a new variety.) Matthew separates a form with a thicker shell and straighter cardinal margins as the variety rohusta. My impression is that these characters are so largely the result of the con- dition of preservation of the specimens in the matrix that the variety has very little value. Formation and locality.— Middle Cambrian : (lOp) Sandstone just below the waterfall in Division E2b of Matthew's [1903, p. 21] Etcheminian, on Dugald Brook, Indian River; (lOpO sandstone one-fourth mile (0.4 km.) from lower bridge, on Gregwa Brook, Indian River; (lOp") sandstone on the small brook on the hill between the bridge over Indian River and McPhees Brook; (13t") sandstones of Divisions Elc and Eld of Matthew's [1903, p. 21] Etche- minian, on Dugald Brook, Indian River; (344Ii [Matthew, 1903, p. 79]) sandy layers in the shales of Division Ele of Matthew's [1903, p. 21] Etcheminian, on Dugald Brook, Indian River; and (344m [Matthew, 1903, p. 78]) sandy shales of Division Eld of Matthew's [1903, p. SI] Etcheminian, on Dugald Brook, Indian River; all in eastern Cape Breton, Nova Scotia. Lingulella (Lingulepis) longineevis (Matthew). Plate XLIV, figures 2, 2a-g. Lingulepis longinervis Matthew, 1903, Geol. Survey Canada, Rept. Cambrian Rocks Cape Breton, pp. 133-135, PI. VII, figs. 6a-g. (Described and discussed as a new species. The specimen represented by figure 6f is redrawn in this monograph, PI. XLIV, fig. 2e.) This species diifers from Lingulella (Lingulepis) gregwa (Matthew) in having the sides of the ventral valve extended in a nearly straight line beyond the center of the valve. Some of Matthew's specimens have a concentrically striated surface with only a trace of the character- istic surface of L. (L.) gregwa. Others show more of the ornamented surface, and in specimens a Doubtfully identified from this locality. 556 CA]\IBRIAN BRACHIOPODA. collected bj' S. Ward Loper from the same beds from which the types of L. (L.) longinervis came, the surface is indistinguishable from that of L. (L.) gregwa. Matthew [1903, p. 134] considers the long, large "visceral callus" of the doi-sal valve as the most prominent characteristic of this form. I find in L. (i.) gregwa (Matthew) and L. (L.) exigua (Matthew) that the visceral area in many specimens extends nearly to the front of the dorsal valve and that the length and strength of the visceral area in both ventral and dorsal valves of Lingulepis are not usual!}' characters to be depended upon as criteria for specific determinations. The position assigned to the central and anterolateral muscle scars by Matthew [1903, PI. \T!I, figs. 6e and 6f] appears to be theoretical, as a most careful study of the typ- ical specunens fails to locate them as indicated in the figures. In fact, the specimens are too poorly preserved to indicate clearly where the scars are. Fine casts of the interior collected by Loper show the scars named farther toward the central portion of the shell. LinguleTla {Lingulepis) longinervis differs from L. (L.) exigua (Matthew) in its less atten- uate ventral valve and less robust character in both size and thiclaiess of shell. The specimens collected by Matthew are small and do not show the variation that exists in the collection made by Loper. In a laj^er of reddish brown sandstone Loper found a great number of shells varying in size and form from those similar to Matthew's types to shells nearly twice as large. In a layer of hard graj^ standsone, 5 feet above, all the specimens are similar in size and form to those collected by Matthew. LinguleTla triparilis (Matthew) occupies a position intermediate in form between L. (L.) gregwa (Matthew) and L. (i.) longinervis, and the surface characters of the three species are essentially of the same type. Formation and locality. — Middle Cambrian: (372f) shales of imknown stratigi-aphic position; (13d") sand- stones 10 feet (3 m.) below Division E2a; (13g) sandstones 10 feet (3 m.) above Division E2a; (13f) sandstone 20 feet (6 m.) above Division E2a; {13p and 13p') sandstones 40 to 45 feet (12.2 to 13.6 m.) above Division E2a; (13d) sand- stones opposite the thuxl waterfall in Dugald Brook, between Divisions E2a and E2b; (lOp) sandstones just below the waterfall, ia Division E2b; (344o [Matthew, 1903, -p. 134]) sandstones of Division ESb; and (131) shaly sandstones of Division E3a; all in Matthew's [1903, p. 21] Etchemuiian, on Dugald Brook, Indian River, eastern Cape Breton, Nova Scotia. (lOp') Sandstone one-fourth mile (0.4 km.) from lower bridge, on Gregwa Brook, Indian River; and (lOp") sand- stone on tlie small brook on the hill between the bridge over Indian River and McPhees Brook; both in eastern Cape Breton, Nova Scotia. LiNGTJLELLA (LiNGtJLEPis) PUMiLA (Matthew!) Plate XLV, figures 3, 3a. Lingulepis pumila Matthew, 1903, Geol. Survey Canada, Rept. Cambrian Rocks Cape Breton, p. 75, PI. VII, figs. 5a and 5b. (Described as a new species. The specimens represented by figs. 5a and 5b are redrawn in this monograph, PI. XLV, figs. 3 and 3a,_ respectively.) This species differs from Lingulella triparilis (j\Iatthew) and LinguleTla (Lingulepis) gregwa (Matthew) in having a more attenuate ventral valve. In this respect it resembles the narrow forms of L. (L.) longinervis (Matthew). The material is poor, so that only the general form can be used to characterize it. One dorsal valve shows that the shell was thick, very much as in L. (L.) exigua (Matthew). The surface of exfoliated shells is nearly smooth. Matthew [1903, p. 75] describes the outer surface as consisting of irregular concentric ridges, about six in the space of a millimeter. Formation and locality. — Middle Cambrian: (344f [Matthew, 1903, p. 72]) Shales in the Coldbrook terrane of Matthew, on Dugald Brook, Indian River, eastern Cape Breton, Nova Scotia. Specimens that are somewhat doubtfully referred to this species occur at the following locality : Middle Cambrian: (13k) Shales of Matthew's [1903, p. 15] Coldbrook, above tlie great fall in Dugald Brook, Indian River, easteiTi Cape Breton, Nova Scotia. Lingulella (Lingulepis?) pygjlea (Salter). Plate XXX, figure 10. Lingula pygmxa Salter, 1865, Quart. Jour. Geol. Soc. London, vol. 21, p. 102, figs. 8a and 8b, p. 101. (Described as a new species; see p. 557 for copy. Figs. 8a-b are copied in this monograph, PL XXX, fig. 10.) OBOLID.E. 557 Lingula pygmxa Salter, Davidson, 1866, British Fossil Brachiopoda, vol. 3, pt. 7, No. 1, p. 53, PI. II, figs. 8 and 8a. (Text and figures copied from the preceding reference.) Lingula pygmsea Salter, Phillips, 1871, Geology of Oxford and the Valley of the Thames, p. 68, Diagram XVII, fig. 13. (No text reference.) Lingula pygmxa Salter, Matlet, 1902, Quart. Jour. Geol. Soc. London, vol. 58, p. 141. (Synonymy given and species mentioned.) The original description by Salter follows : Minute, subcylindrical, gibbous; beak somewhat obtuse; anterior margin truncate; shell thin; sm-face finely striated transversely. Length, jV inch; width, ^V inch. In the Black shales. The Black shales are referred to the Upper Cambrian, the locality being in the eastern por- tion of the Malvern Hills of England. Davidson [1866, p. 53] states that he could only repro- duce Salter's description and figure, as he had not seen specimens of the shell. The figure given by Salter [1865, figs. 8a and 8b, p. 101] is that of an elongate, cuneate shell more Uke the tj^pical form of Lingulepis than Lingulella. From its form and the fact that it occurs in association with the Olenus fauna it is probable that it should be referred to Lingulepis. Formation and locality. — ^Upper Cambrian: (304f [Salter, 1865, p. 102]) "Black shales" in the Malvern Hills, between Herefordshire and Worcestershire, England. Lingulella (Lingulepis) eobeeti (Matthew). Plate XXXVII, figures 4, 4a-d. Lingulella Toberti 'MATTSBVf , 1895, Trans. Roy. Soc. Canada for 1895, 2d ser., vol. 1, sec. 4, No. 13, pp. 256-257, PI. I, figs. 2a and 2b. (Described and discussed as a new species. Plate XXXVII, figs. 4, 4a-d of this monograph are drawn from specimens in Matthew's type material, and it is possible that the specimens represented by figs. 4a and 4b are the ones figured by Matthew, figs. 2a and 2b, respectively, but positive identification is impossible.) Lingulepis roberti Matthew, 1903, Geol. Survey Canada, Rept. Cambrian Rocks Cape Breton, p. 132, PI. VIII, figs. 5a-b. (Text and figures copied from the preceding reference.) General form elongate ovate, with the ventral valve acuminate and the dorsal round ovate. The cardinal slopes of the ventral valve are in some shells slightly incurved as in Lingulella (Lingulepis) acuminata (Conrad); a portion of this curvature, as shown in Plate XXXVII, figures 4 and 4a, may be owing to the lateral compression of the shells. The convexity of the ventral valve is moderate, while that of the dorsal is unusually large (PI. XXXVII, fig. 4b). This may be owing to the deformation of the shell by lateral pressure in the matrix. Surface of the shell marked by very fine, obscure, radiating striae and narrow undulations, and very fine, irregular, concentric strife between relatively strong strise and fines of growth. The irregular striae inosculate, Plate XXXVII, figure 4c, so as to give an appearance much like that of Obolus (Westonia) ella (Hall and Whitfield) (PL XLVII, fig. lo). When the thin outer layer is exfohated, the dark shiny surface of the inner layers shows radiating stri^ and concentric fines of growth. The inner surface appears to have been punctate to a moderate degree. The sheU is moderately thick and is built up of a thin outer layer and several inner layers or lamellae that anteriorly are sfightly oblique to the outer layer, much as in Lingulella acutangula (Roemer). The largest ventral valve among the type specimens has a length of 13 mm.; mdth, 9 mm.; the width is narrowed 2 or 3 mm. by the lateral compression. A dorsal valve that is very fittle, if any, distorted is 10 mm. long and 10 mm. wide. A trace of the pedicle groove in the ventral valve is shown by Plate XXXVII, figure 4a. The area of the dorsal valve is not preserved in any of the specimens sent to me by ^Matthew. The cast of the visceral cavity is shown in Plate XXXVII, the ventral valve in figure 4a and the dorsal valve in figure 4b. The anterior lateral and central muscle scars are seen in the specimens of the type sent me by Matthew. In g and h, figure 4b, of Matthew's figures, the umbonal scar is short and broad, as in Obolus selwyni (Matthew) (PI. XXXVII, fig. If). The markings of the vascular system observed are the main vascular sinuses of the ventral valve, a trace of them in the dorsal valve, and a little of the parietal scar about the visceral cavity in the dorsal valve (fig. 4b). 558 CAMBRIAN BRACHIOPODA. Observations. — Tliis species is related by its form to Lingulella (Lingulepis) gregwa (Mat- thew) and L. (L.) longinervis (]\'Iatthew), but it differs in its surface cliaracters. In its very- fine, irregular striae and general form it is closely allied to L. (L.) exigua (^latthew). The thick, robust shell and numerous strong pits on the inner surface of the shell give the latter a character not seen in L. (L.) roberti. The ■\asceral area and muscular scars of the ventral and dorsal valves are much like those of Obolus selwyni (Matthew) (PL XXXVII), and in specimens of the same size occupy relatively the same position. The specific variations between the two species appear to be in the shape of the valves and the character of the fuier ornamentation of the surface. Matthew originally [1895, p. 257] referred this species to the Ordovician fauna, but in his review of the Cambrian fauna of Cape Breton [1903, p. 132] it is referred to his lower Etcheminian. The specific name was given in honor of Mr. J. Alfred Robert, of the Geological Survey of Canada, who collected the specimens of the species. Formation AND LOCALITY. — Middle Cambrian : (307d [Matthew, 1903, p. 132]) Sandy limestone of Division E2a? of Matthew's Etchemiiiian, on Young (McFees) Point [Matthew, 1903, p. 19], near George River station, Cape Breton, Nova Scotia. Lingulella (Lingulepis) rowei (Walcott). Plate XXI, figures 4, 4a-b. Obolus (Lingulepis) rowei Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 334. (Characterized as a new species.) This shell differs from Lingulella (Lingulepis) acuminata (Conrad) and other species of Lingulella and Lingulella (Lingulepis) in the sharp, fine, concentric ridges of the outer surface, about six to the milhmeter. This surface resembles closety that of Obolus (Palse-obolus) bre- tonensis Matthew. The material is not well preserved, but there is sufficient to illustrate the form of the valves and the character of the surface. A fragment shows a more attenuate posterior portion of a ventral valve than the one illustrated. The specific name is given in memory of Mr. R. B. Rowe, assistant geologist of the United States Geological Survey, who collected the material a short time before his death. Formation and locality. — Lower Cambrian: (14p) Reddish-brown quartzitic sandstone, near Resting (Fresh- water) Springs, which is in the southwest corner of T. 21 N., R. 8 E., on Amargosa River, in the southeastern part of Inyo County, California. Lingulella (Lingulepis) spatula (Walcott). Plate XIX, figures 5, 5a-b. Obolus (Lingulella) spatulus Walcott, 1902, Proc. U. S. Nat. Mus., vol. 25, p. 607. (Described and discussed as below as a new species.) General form of the ventral valve spatulate, the sides sloping from the apex forward with a very slight curvature to the anterior fifth of the shell, where they pass into the broadly rounded frontal margin. Dorsal valve ovate with the greatest width toward the front. Convexity moderate, and about equal in both valves. A ventral valve 9 mm. in length has a convexity of about 1 mm. A fragment of the outer surface indicates that the surface was relatively smooth, being broken only by fine, scattered striae of growth. The inner layers show concentric lines, also fine, radiating striae. The interior of the shell was marked by scattered pustules, concentric striae, and a few radiating lines. The largest ventral valve has a length of 9 mm. and a width of 6 mm. A dorsal valve 5 mm. in width has a length of 7 mm. The only trace of the vascular system preserved is the median ridge, of the dorsal valve, which extends forward to the anterior fourth of the shell. Observations. — This very pretty little shell occurs in abundance in the chocolate brown sandstone interbedded in the shales, just above the massive "Tonto" sandstone. It is distinct OBOLIDiE. 559 from all other species known to me from the Cambrian rocks of the Grand Canyon region. Oholus ( Westonia) cJiuarensis (Walcott) occurs in a layer of sandstone 50 or 60 feet higher up in the section. Formation and locality. — Middle Cambrian: (74d) Sandstone beds in "Tonto" shale just above massive sandstones near mouth of Bass Canyon, on the south side of the Grand Canyon of the Colorado, southeast of Powells Plateau, Arizona. LiNGIILELLA (LiNGTJLEPIS ?) SQUAMOSA (HoU). Plate XXX, figure 9, Lingula squamosa Holl, 1865, Quart. Jour. Geol. Soc. London, vol. 31, pt. 1, p. 102. (Described as a new species; see below for copy.) f Lingula squamosa Holl, Davidson, 1866, British Fossil Brachiopoda, vol. 3, pt. 7, No. 1, p. 41, PI. II, fig. 7. (Copies the original description and discusses species. Fig. 7 is copied in this monograph, PL XXX, fig. 9.) The original description by Holl follows : Triangular, broad anteriorly, compressed; beak acute; anterior margin truncate; shell thick, strongly grooved from side to side by imbricating lines of growth. Length, one-fourth inch. In the light-brown felspathic sandstone of the Holly bush series. The sandstone of the Hollybush series is beneath the Black shales in which Lingulella (Lingulepis?) pygmxa (Salter) occurs, but appears to form a portion of the Upper Cambrian of the Malvern Hills section. The species has a pecuhar cuneate form, more like that of L. (L.) acuminata (Conrad) tlian any other European shell Itnown to me. On this account it is referred to the subgenus Lingulepis. Formation and locality. — Upper Cambrian: (304g [Holl, 1865, p. 102]) Sandstones of the Hollybush series, Malvern Hills, between Herefordshire and Worcestershire, England. Lingulella (Lingulepis) starri (Matthew). Plate XXXVII, figures 2, 2a-b. Lingulella starri Matthew, 1891, Trans. Roy. Soc. Canada for 1890, 1st ser. vol. 8, sec. 4, No. 6, pp. 146-147, PI. XV, figs. 5a-c, 6a-b. (Described and discussed as a new species. According to Matthew the type specimens have been mislaid or lost, and the specimens represented in this monograph are from new material collected by him.) Lingulepis starri Matthew, 1903, Geol. Survey Canada, Rept. Cambrian Rocks Cape Breton, p. 195. (Mentioned.) General form cuneate, elongate ovate, with the ventral valve obtusely acuminate and the dorsal valve broadly ovate; valves appear to have been moderately convex. Outer surface of the shell marked by fine, concentric, shghtly irregular striae, 8 to 12 in the space of a milh- meter; when the outer layer of shell is exfoliated coarser concentric striae are seen; and on the umer surface of the shell strong concentric striae and numerous radiating strise occur, the latter being most prominent on the anterior half of the valves. The shell is strong and is built up of a thia outer layer and several inner layers or lamellse, very much as in Lingulella acutan^ gula (Roemer). A large ventral valve, as measured by Matthew, has a length of 16 mm.; width, 14 mm. A cast of the interior of a broken ventral valve shows the visceral cavity (v) and a trace of the main vascular sinus (PL XXXVII, fig. 2b) . Observations. — This is one of the large species of the genus and compares in this respect with Lingulella ampla (Owen) and Oholus ( Westonia) aurora (Hall) . Matthew wrote me that the type of this species had been mislaid or lost. The illustrations are taken from other speci- mens identified and labeled by him. The specific name was given in honor of Mr. R. P. Starr, who discovered the species. Formation and locality. — Upper Cambrian: (308c [Matthew, 1891, p. 147]) Shales of Division 2h of Matthew's Johannian at St. John; and (2x) thin-bedded sandstones of Division 2 of Matthew [1892, p. 59], on the south shore of Long Island, Kennebecasis Bay [Matthew, 1898a, pp. 124 and 127]; both in St. John County, New Brunswick. 560 CAl'IBRIAN BRACHIOPODA. LiNGULELLA (LiNGULEPIS ?) sp. Undt. (Walcott). Obolus (Lingulepis) sp. undt. Walcott, 1906, Proc. U. S. Nat. Mus., vol. 30, pp. 567-568. (Characterized as below as an undetermined species.) This species is represented by a few fragments, one of which shows that the ventral valve is elongate, and the apex acuminate. The shell was built up of several layers or lamellae, as in characteristic forms of Lingulella (Lingulepis). The interior surface of some of the lamellae is marked by fine, racUatmg, and concentric strise; the outer surface, under a strong magnifier, shows fine, concentric, somewhat irregular striae. Formation and locality. — Middle Cambrian: (C72) Tiiin green-gray limestone interbedded with ocherous and green clay shales, overlying the massive oolite in the Kichou formation [Willis and Blackwelder, 1907, pp. 139 and 145 (3d list of fossils)], 4 miles (6.4 km.) east of Fanglanchon, Shansi, China. Genus DEIiGADELLA Walcott.a Delgadella Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 4, PI. XI, and pp. 142 and 144. (Classification of genus.) The description of the type species includes all that is known of this genus. The form of the shell is more Mke that of Lower Ordovician species referred to Lingula than to the typical forms of Lingulella or Lingulepis. Type. — Lingulepis lusitanica Delgado. The generic name is given m memory of the late Mr. J. F. Nery Delgado, of the Geological Survey of Portugal. Delgadella lusitanica (Delgado). ' Plate XXIX, figures 5, 5a-b. Lingulepis lusitanica Delgado, 1904, • Communicafoes Commissao Servigo Geologico Portugal, tome 5, fasc. 2, pp. 365-366, PI. IV, figs. 31-34. (Characterized and discussed in French as a new species. Photographs of the specimens represented by figs. 31, 32, and 34 are reproduced in this monograph, PI. XXIX, figs. 5a, 5b, and 5, respectively, each individual figure being a reversed view of Delgado's original figure.) General form elongate ovate, moderately convex. The greatest width of the ventral valve is at the anterior third, whence the outhne narrows slightly to the broadly rounded front, and gradually to the subacuminate posterior half. Dorsal valve unlcnown, unless Plate IV, figure 17, and possibly figure 27, of Delgado, represents it. However, these two shells are referred in this monograph to Lingulella delgadoi (p. 491) as they appear to be more closely related to that species than to Delgadella lusitanica. Shell thick and with a thick margin. This is shown by the casts of the edges of the valves, as shown by figures 5 and 5a. Shell substance unknown. Delgado [1904, p. 365] states that the shells range fi'om 5 to 8.5 mm. in length. Observations. — Delgado referred tliis species to Lingulepis on account of its general form, but from the fact that it has a tliick, strong shell and does not have the attenuated extension of the apex of the ventral valve of the typical forms of Lingulepis I am inclined to refer it to a new genus characterized by a thick shell, spatulate form, with a subacuminate beak. A shell agreeing with tliis in outline and form occurs in the Lower Ordovician shales at Kelleys Island, Conception Bay, Newfoundland. Delgado [1904, p. 365] compares tliis species with the very young shells of Lingula lesueuri Rouault [Davidson, 1866, PL I, figs. 1-11]. If the specimens representing it had been sent to me without any information as to the associated fauna, I should have been strongly inclined to refer them to a Lower Ordovician fauna. Lingulella {Lingulepis) acuminuta meeki (Walcott) has a somewhat similar outline, but that is a thin, corneous shell of the Upper Cambrian fauna. We must await further discov- eries of more perfectly preserved material before a more complete description can be given. o Prior to the deflnition of the genus Delgaiella the type species was described under Lingulepis [Delgado, 1904, p. 3651. OBOLiD.^i:. 561 Mr. Delgado very kindly sent me a specimen of this species, also some large photograjDlis of specimens illustrated by him. I have reproduced three of these in illustration of the species. Formation and locality. — Lower Cambrian: (351 [Delgado, 1904, p. 365]) Shales at Monte de Valbom, north- east of Villa Boim, Province of Alemtejo, Portugal. Subfamily ELKANUN.^ Walcott and Scliucliert. Genus ELKANIA Ford.« Billingsia Ford [not De Koninck, 1876], 1886, Am. Jour. Sci., 3d ser., vol. 31, pp. 466-467. (Described and discussed as a new genus.) Not Billingsia Walcott, 1886, Bull. TJ. S. Geol. Survey No. 30, pp. 5, 21, 60, and 62. (Used in lists for a genus of the Gastropoda.) Elkania Ford, 1886, Am. Jour. Sci., 3d ser., vol. 32, p. 325. (Proposes Elhania for Billingsia, which was preoccupied.) Elhania Ford, Hall and Clarke, 1892, Eleventh Ann. Kept. State Geologist New York for 1891, p. 241. (Described.) Elhania Ford, Hall and Clarke, 1892, Forty-fifth Ann. Rept. New York State Museum for 1891, p. 557. (Copy of preceding reference.) Elhania Ford, Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, pp. 75-78. (Copies part of Billings's, 1861b, p. 70, description of "Obolella desiderata" and Ford's, 1886a, p. 467, description of the genus, and describes and discusses genus.) Elkania Ford, Walcott (in part), 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 321-323. (Described and discussed essen- tially as below. The text includes reference to species now placed under Oholus {Fordinia).) Elkania Ford, Walcott, 1908, Smithsonian Misc. CoU., vol. 53, No. 4, PI. XI, and pp. 142 and 144. (Classification of genus.) General form ovate, biconvex; shell substance corneous and made up of several thin layers or lameUse that increase in number toward the front and lateral margins. Surface marked by fine concentric striae of growth. Apex of both ventral and dorsal valves marginal. The inte- rior of the ventral valve has a thickened posterior section which has a central pedicle furrow and two flexure lines running obliquely forward and outward from the apex, a little inside of the grooves of the main vascular trunks; this structure is apparently the result of the union of the area with the bottom of the shell so as to bring, as the shell grew, the path of advance of the pedicle groove, main vascular sinuses, and lateral muscle scars all on one surface instead of on the area and the shell beneath it as in Oholus. The muscle scars are arranged as in Oholus. The transmedian and anterior laterals occur well out toward the margin (PI. LI, fig. 1) and the space inclosing the central, middle lateral, and outside lateral scars is in the central area, on the front of the slope of the thickened posterior portion of the valve (PI. LI, figs. 1 and 3a) ; the points of attachment of the individual muscles can not be distinguished. In the dorsal valve the central and anterior lateral scars are. clearly shown in several specimens; the transmedian and outside laterals are situated just outside the main vascular sinus (PI. LI, fig. Ic). Our knowledge of the vascular markings is limited to the main vascular sinuses, except in one ventral valve, where the inner branches have been preserved; in both valves the main trunk rises near the apex and its path is outlined across the internal cardinal area. The preceding description differs materially from that of Ford [1886a, p. 467] and HaU and Clarke [1892c, p. 77]. I find the muscle scars as described above and am compelled to consider them as indicating the same muscles as in Oholus. That the genus is an advance on Oholus in the evolution of the inarticulate brachiopods I quite agree with Hall and Clarke [1892c, p. 165], but not that it is a stage ia the transition from Oholus to Trimerella and its allies. (See remarks on platform, p. 309.) Elkania is an OholUs with the cardinal areas within the plane of the margins of the valves. In the type species, Elkania desiderata (Billings), the area of the ventral valve is entirely within the valve, while that of the dorsal valve has been nearly obliterated in the process of change from an open backward-facing area to an inclosed forward-facmg oThe synonymy for this genus does not give a complete record of the various genera under which the species now included in Elkania were formerly placed; it gives only those references in which the genus is discussed or described. To complete the record the following mere generic references are listed: Oiolella Billings [lS62d, pp. 69 and 71]. I Obolella f Walcott (lS84b, p. 67; lSS6b, p. 111). Obolella Davidson [1868, p. 309). | 62667°— VOL 51, pt 1—12^—36 562 CAJMBRIAN BRACHIOPODA. area. A comparison of the interiors of Obolus apollinis Eicliwald (PI. VII, figs. 1-17) with those of Oholus (Fordinia) hellulus (Walcott) (PI. LI, figs. 3a-f) and Elkania desiderata (Billings) (PI. LI, figs. 1, la-d) ilhistrates how httle change is necessary to convert the exterior cardinal areas of Obolus into the inclosed internal areas of ETkania. As the beaks of Elkania are marginal, the pedicle passed out through an opening made by the gaping of the valves. The tln-ee known species of the genus are the type species Elkania desiderata (Billings), E. amhigiM (Walcott), in wliich the shell is' very thick, and E. ida (Billings). Authors have referred frequently to the resemblance between species of Oholella and Elkania desiderata. This does not appear to exist except in a superficial manner. Oholella is a stage in the evolution toward the Siphonotretidas, whereas Elkania has no known descendants. The generic name was given in honor of Dr. Elkanah BiUings, of the Geological Survey of Canada. Elkania ambigua (Walcott). Plate LI, figurea 2, 2a-c. Oholella f ambigua Walcott, 1884, Mon. U. S. Geol. Survey, vol. 8, pp. 67-68, PL I, figs. 2a-c. (Described and discussed as a new species. The specimens represented by figs. 2a-c are redrawn in this monograph, PL LI, figs. 2a, 2, and 2b, respectively.) Billingsia 1 ambigua (Walcott), Ford, 1886, Am. Jom-. Sci., 3d ser., vol. 31, p. 467. (Generic relations mentioned.) Elkania ambigua (Walcott), Ford, 1886, idem, vol. 32, p. 325. (Merely changes generic reference.) Elkania ambigua (Walcott), Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, ^t. 1, p. 78. (Generic relations discussed.) General form ovate; biconvex; beaks marginal. Surface marked by fine concentric striae of growth. Substance of shell corneous as far as can be determined, although some of the layers appear to be calcareous. The shell is made up of many thin layers or lamellae. Ventral valve elongate oval, moderately convex. Dorsal valve transversely broad ovate; the interior shows a slender median septum at the bottom of a shallow, concave, well-defined visceral area; within the latter area the central muscle scars occur at the outer margins about one-half the distance from the posterior margin to the anterior margin of the visceral area; the anterior lateral scars are close together on each side of the median septum at the anterior margin of the area; the thickening of the shell varies greatly in different shells; in some it extends far to the front (PL LI, fig. 2c) and in others it is scarcely noticeable (fig. 2b). No interiors of the ventral valve have been found and the cardinal area of the dorsal valve is unkno^vn. The largest dorsal valve has a length of 9 mm.; width, 10 mm. This species m size and form is related to E. desiderata (Billmgs) ; it differs in the character of the interior of the dorsal valve, and in having a thicker and stronger shell m the adult stage. When the species was first described its relations were uncertain, hence the specific name. Formation and locality.— Lower Ordovician: (63) Base of the Pogonip limestone, northeast of Adams Hill; and (202) Pogonip limestone, on the summit of the ridge directly southeast of the Jackson mine, northwest of Shadow Canyon; both in the Eureka district [Hague, 1892, Atlas], Eureka County, Nevada. Elkania desiderata (Billings). Plate LI, figures 1, la-d. Obolella desiderata Billings, 1862, Geol. Survey Canada, Paleozoic Fossils, vol. 1, pp. 69-70, figs. 62a-b. (Described and discussed as a new species. The specimens represented by figs. 62a and 62b are redrawn by Hall and Clarke, 1892c, PL III, figs. 16 and 17, respectively.) Obolella desiderata BilUngs, Davidson, 1868, Geol. Mag., vol. 5, figs. 1 and 2, p. 309. (Mentioned.) Obolella f desiderata BiUings, Walcott, 1886, Bull. U. S. Geol. Survey No. 30, p. 111. (Generic relations discussed.) Billingsia desiderata (Billings), Ford, 1886, Am. Jour. Sci., 3d ser., vol. 31, pp. 466 and 467, fig. 1, p. 466. (Generic relations discussed.) Elkania desiderata (Billings), Ford, 1886, idem, vol. 32, p. 325. (Merely changes generic reference.) Elkania desiderata (BiUings), Hall and Clarke, 1892, Eleventh Ann. Kept. State Geologist New York for 1891, PI. Ill, figs. 13 and 14. (No text reference. Figs. 13 and 14 are drawn from casts of the two specimens figured by BilUngs, 1862d, figs. 62a and 62b, p. 68, the specimens themselves being redrawn in Hall and Clarke, 1892c, PL III, figs. 16 and 17, respectively.) OBOLID.^. 563 Elkania desiderata (Billings), Hall and Clahke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, pp. 76 and 77, PI. Ill, figs. 15-19. (Part of original description, Billings, 1862d, p. 70, copied on p. 76 and species described and discussed. Figs. 16 and 17 are drawn from the specimens figured by Billings, 1862d, figs. 62a and 62b, p. 68; figs. 15 and 18, which represent casts of the specimens represented by figs. 16 and 17, respectively, are copied fi'om figs. 13 and 14 of the preceding reference.) The species has been so thoroughly described by Bihings [1862d, p. 69], Ford [1886a, p. 466], and Hall and Clarke [1892c, p. 77], from their respective points of view, that I will confine my observations to the interior characters. As noted under the genus, I regard the cardinal areas as being reversed ; that is, slopmg within the plane of the margins of the valves instead of with- out, as in Oholus; the space beneath the area and the bottom of the valve is filled with shell, and the margin of the area thus disappears in the anterior slope of the thickened portion of the shell. The scheme of muscle scars, as far as they are known, is the same as in Oholus. In the ventral valve the anterior laterals (j) and transmedians (i) occur outside the main vascular sinuses toward the margin of the valve and in front of the included cardinal area. The space occupied by the central and middle and outside lateral scars is defined on the front slope of the umbonal thickening of the valve. The muscle scars of the dorsal valve include the transme- dian and outside laterals on the outer margin of the mam vascular sinuses, and the central and anterior laterals on the margins of the central visceral area. The vascular markings include the main vascular sinuses in the two valves, and some inner branches in the ventral valve. Elkania desiderata differs from E. amhigua (Walcott), the only related species, in the interior of the dorsal valves, which are the only parts we have for comparison. The shell is also thinner. Formation and locality. — Lower Ordovician: (319a) Levis shales. Point Levis, Province of Quebec, Canada. Elkania ida (Billings). Plate XXX, figures 20, 20a; Plate LI, figures 4, 4a-c. Oholella ida Bilungs, 1862, Geol. Survey Canada, Paleozoic Fossils, vol. 1, p. 71, fig. 63a-b._ (Described and dis- cussed as a new species, see below for copy.) Oholella? ida Billings, Walcott, 1886, Bull. U. S. Geol. Survey No. 30, p. 111. (Generic relations mentioned.) Billingsiaf ida (Billings), Ford, 1886, Am. Jom\ Sci., 3d ser., vol. 31, p. 467. (Generic relations mentioned.) Elkania ida (Billings), Ford, 1886, idem, vol. 32, p. 325. (Merely changes generic reference.) The original description by Billings follows: Shell small, obtusely ovate, greatest width at or a little in front of the middle, abruptly narrowed to the beaks, sides and front margin uniformly rounded, the front slightly less convex than the sides. Both valves equally and rather strongly convex, most elevated at about one-third the length from the apex, thence sloping with a gentle curve to the sides and front margin, abruptly descending on each side of the beak and umbones. Ventral valve slightly more pointed above than the dorsal; umbo narrowly convex; beak apparently depressed to the level of the lateral margin. Dorsal valve obtusely angular or narrowly rounded at the beak, the latter not visibly distinct from the cardinal edge; umbo obtusely convex. Surface with a somewhat shining aspect, with very fine concentric striw; a few radiating strife are visible on two of the specimens. Shell apparently very thin. Length of a perfect ventral valve, 2 lines; width, 1| lines. -The length and width of the dorsal valve are about equal. In some material from the McGill University Museum, kindly lent to me by Sir William Dawson and Dr. Frank D. Adams, I found some fine specimens labeled Oiolella ida, collected by J. Richardson. These specimens show the characters described by Billings [1862d, p. 71] and in addition the following: The shell is corneous and built up of manj^ lamellae or layers arranged obliquely to the surface so as to form a thick, strong shell. The interior of the ventral valve has a thickened umbonal portion with a pedicle groove much like that in E. desiderata (Billings), but much shorter m proportion; owing to the imperfect condition of the remaining portions, no further details can be determined. The interior of the dorsal valve shows a thickened elevated area like that of the dorsal valve of E. desiderata (PL LI, fig. Id), but differ- ently shaped. A large transverse depression just in advance of the posterior margin appears 564 CAMBRIAN BRACHIOPODA. to be all that is left to indicate the cardmal area; the central muscle scars are situated just in advance of this depression and the anterior laterals at the front end of the visceral area ; the position of the transmedian and outside lateral scars is indicated by an elongate scar near the posterolateral margm, just in advance of the traces of the cardinal area. Vascular markings unlviiown. This species differs from E. desiderata in having a thicker and more convex shell and has a difi'erently shaped visceral area in the dorsal valve. Formation and locality. — Lower Ordovician: (319) « Limestone No. 1 of Billings'is section; and (319i) limestone of Billings's section; both at Point Levis, Province of Quebec, Canada. Subfamily NEOBOLIN^ Walcott and Scliucliert. Genus NEOBOLTJS Waagen. [vkot;, young; and Obolus. Neobolus AVaagen, 1885, Mem. Geol. Survey India, Paleontologia Indica,.13th ser.. Salt Range Fossils, vol. 1, pt. 4, fas. 5, pp. 756-758. (Described and discussed as a new genus.) Davidsonella Waagen [not Munibr-Chalmas, 1880], 1885, idem, pp. 762-764. (Described and discussed as a new genus.) Neobolus Waagen, Oehleet, 1887, Manuel de conchyliologie, by Fischer, p. 1263. (Described in French, with figures of Neobolus u'arthi.) Lakhmina Obhlert, 1887, idem, p. 1265. (Described in French, with figures of " Lakhmina linguloides.") Lahhmina Oehlert, Waagen, 1891, Mem. Geol. Survey India, Paleontologia Indica, 13th ser., Salt Range Fossils vol. 4, pt. 2, description of PI. II, figs. 3-A. (No text reference.) Lahhmina Oehlert, Hall and Clarke, 1892, Eleventh Ann. Rept. State Geologist New York for 1891, pp. 234-235. (Described.) Neobolus Waagen, Hall and Clarke, 1892, idem, p. 245. (Described.) Lahhmina Oehlert, Hall and Clarke, 1892, Forty-fifth Ann. Rept. New York State Museum for 1891, pp. 550-551. (Copy of Hall and Clarke, 1892a, pp. 234-235.) Neobolus Waagen, Hall and Clarke, 1892, idem, p. 561. (Copy of Hall and Clarke, 1892a, p. 245.) Lakhmina Oehlert, Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, pp. 28-30. (Described and discussed.) Neobolus Waagen, Hall and Clarke, 1892, idem, p. 84. (Described and discussed.) Neobolus Waagen, Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, pp. 72-76. (Described and discussed as below, with the exception of the paragraph desciibing the two text figures.) Neobolus Waagen, Walcott, 1908, idem, vol. 53, No. 4, PI. XI, and pp. 142 and 144. (Classification of genus.) General outhne of shells broad oval to subcircular; nearly equivalve, moderately convex. Shell substance calcareocorneous and probably phosphatic, structure laminated. Surface with concentric striation. Shell strong for its size and built up on its anterior and lateral margins of several thin layers or lamellae. Apex of ventral valve small and shghtly" projecting over a low false area that appears to have an open delthyrium. Apex of dorsal valve marginal. The interior of the ventral valve has a strong, rounded, central ridge extending from the narrow area, about one-third the length of the shell, and a strong ridge on each side that extends from the same point of origin as the central ridge obliquely forward nearly to the frontal margin of the shell ; '' between the central ridge and the posterior portions of the lateral ridges there are sUghtly concave shelves forming, with the central ridge, a triangular platform, with an open space beneath the concave shelves; numerous radiating striae occur on the con- cave shelves and the inner surface of the shell. Of the muscular impressions in the ventral valve, Waagen wrote [1885, p. 762] that "nothing can be observed." Considered fi-om the point of view of the Trimerellidse, this may appear to be correct, but if we compare the muscle scars of Oholus with what appear to me to be points of attachment of muscles in the specimen represented by Plate LXXXI, figure 2e, there is no difficulty in recognizing a few scars. Just beneath the outer extension of the narrow area of the ventral valve there is a minute, clearly defined, elongate, oval space that corresponds to the divided umbonal muscle scar in Obolus apollinis Eichwald; near the Outer oThis is the locality from which the species is listed in the collections ol the Geological Survey of Canada. Billings [18fi2b, p. 71) also identifies the species from No. 2 of his section. 6 1 do not find any indication of the incurving of these ridges as described and illustrated by Waagen [1885, p. 762, PI. LXXXV, fig. 6]. OBOLID^. 565 margin, on a line with the anterior portion of the central ridge, there is a narrow elongate space which, under a strong reflected light, is seen to be divided diagonally by a shght, narrow, raised hne. Compared with Obolus tliis space is the point of attachment of the transmedian and anterior lateral muscle scars. It is probable that the outside and middle lateral muscle scars and the centrals were attached to the platform, but there are no defined muscle scars upon it. The interior of the dorsal valve has several very unusual characters. There is no true cardinal area, unless the thick margin of the shell be considered as such; from the center of the cardinal margin a strong flat process marked by concentric hues of growth projects forward into the valve and rises a Httle above the plane of the margin of the valve. Waagen [1885, p. 763] calls attention to the resemblance between this process and the tooth of TrimereUa lindstromi. From beneath the median process a short, thick platform projects upward and forward into the valve (PI. LXXXI, figs. 2f , 2g, and 2h) ; it is as wide as the process at its base, expanding toward its front margin. It is concave between its lateral crests, and the outer slopes are slightly concave from the crest to the body of the shell; in front the concave space and crests terminate rather abruptly above the front face, which in turn is underlain by a transversely hollow space of unknown extension beneath the platform. Toward each end of the frontal area a minute depression appears to indicate the point of attachment of a muscle. A narrow, rounded median septum extends from beneath the platform well toward the front of the shell. Two more or less interrupted and obscure ridges, indicating the main vascular trunks, extend from the front anterolateral angles at the base of and at the side of the platform obhquely outward into the valve. The elongate smooth spaces outhned by Waagen [1885, PI. LXXXV, fig. 6] in Iris illustrations of this valve are too indefinite to be given form in the drawing of the onl}^ specimen showing the interior. What appears to be a small muscle scar occurs at the cardinal angle ; it corresponds in position to the transmedian scar of Oholus. Figure 47A, page 567, shows the area, median ridge, and side ridges of the visceral area of the dorsal valve. The platform shown by Plate LXXXI, figure 2f, has not been developed beyond the first stages of its growth. It is probable that the fully developed platform occurs only in very old shells. There is no trace of a platform in the specimen represented by Plate I, figure 3, but it may have been broken away. In another shell, not illustrated, there is no trace of thickening beneath the visceral area. In a section of the platform, median ridge, and vas- cular sinuses taken where they unite with the inner surface of the dorsal valve (fig. 47B, p. 567) the platform appears to be intermediate in development between the platforms represented by figure 47A, page 567, and Plate LXXXI, figure 2f. Type. — Neobolus warthi Waagen. Observations. — Through the courtesy of Dr. T. H. Holland, director of the Geological Survey of India, I received the type specimens of Neobolus, Davidsonella, and LaJcJi^nina,. studied, described, and illustrated by Waagen. With these before me I find that the elaborate figures of Waagen [1885, PI. LXXXV] are diagrammatic to a considerable extent, also that I can not clearly recognize some of the characters noted by Waagen. Waagen's original description [1885, p. 762] of the genus "Davidsonella" is very full and he also gives a detailed description of the type species "D. linguloides." Oehlert [1887, p. 1265] evidently based his description of "Lakhmina" on Waagen's description and illustra- tions, apparently not noting that Waagen stated in his text [1885, p. 762] that the elongate area on the sides of the interior of the shell were not muscle scars, but that he considered them as smooth areas outside the crescent. Oehlert [1887, p. 1265], when describing the genus Lalchmina, says, "with a straight and projecting beak perforated for the passage of the foramen." He reproduces Waagen's figures and shows a deep pedicle furrow. This leads me to think that he had Waagen's description and figures in mind when writing his diagnosis of Lalchmina. Only one shell shows the apex of the ventral valve and the small false area beneath, and one other of the interior shows the true area and a triangular depressed spot at the center; a fracture at the center has broken 566 CAMBRIAN BRACIIIOPODA. out a bit of the shell which gives rise to the narrow, cleej) furrow described by Waagen. The ventral valve has (a) a false area beneath the apex, and (b) a true area on a plane with the margins of the valve. When looking over the types of Neoholus and Lakhmina for the purpose of having illus- trations made of them, I noted that there was a strong resemblance between the shells of the two genera, but having the impression that the ventral valve of Lakhmina had a pedicle open- ing at the apex, drawings were arranged on the plates under the conception that Lakhmina belonged with the Neotremata. Schuchert noted the same resemblance when looking over the plates of this monograph and called my attention to it. I then made a careful study of all of the specuuens and by the use of acid developed several interiors of dorsal valves. I found that the supposed perforation of the apex of the ventral valve of Laklimina was the result of the breaking out of the minute apex; that the dorsal valve of Neoholus warthi was the same as the dorsal valve of Lakhmina linguloides and that two genera and four species had been based on specimens of Neoholus warthi. The external characters of all of the shells referred to Neoholus and Lakhmina are the same. Only one specimen of the interior of the ventral valve that shows anything of the platform beneath the visceral area occurs in the collections; this was referred to Lakhmina by Waagen, but the accompanying dorsal valves were first described as Neoholus. By com- paring the illustrations of Waagen [1891, PI. II] the student will notice that figure 8c of the interior of the dorsal valve of Neoholus is essentially the same as the interior of the dorsal valve of Lakhmina (fig. 4c) with the exception of the thickened platform. It may seem as though it were forcing unlike forms into one species to place the specimen represented by Plate LXXXI, figures 2f, 2g, and 2h, with those represented by figures 47A and 47B, page 567, but with our present information it appears to be necessary to do so. AH authors have classified the shells described as Lakhmina linguloides with TrimereUa, and Hall and Clarke [1892c, p. 29] state that in the present condition of knowledge it must be regarded as the earliest representative of the trimerelloid Brachiopoda. The external form, is similar to that of Oholus and the interior characters might readily have been developed from that genus, but the platform is posterior and not central as in the trimerelloids. Neobolus warthi Waagen. Text figures 47A-B, page 567; Plate I, figures 3, 4, 4a-b, 5, 5a; Plate LXXXI, figures 2, 2a-h. Neoholus warthi Waagen, 1885, Mem. Geol. Survey India, Paleontologia Indica, 13tli ser.. Salt Range Fossils, vol. 1, pt. 4, fas. 5, pp. 758-759, PI. LXXXIV, figs. 3-8. (Described and discussed as a new species. The three specimens represented by figs. 4, 5a-b, and 7 are redrawn in this monograph, PI. I, figs. 4, 4a, and 3, respec- tively.) Neoholus wynnei Waagen, 1885, idem, pp. 759-761, PI. LXXXV, figs. 1 and 2. (Described and discussed as a new species. The two specimens represented by figs, la-c and 2a-c are redrawn in this monograph, PI. I, figs. 5 and 5a, respectively.) Davidsonella linguloides Waagen, 1885, idem, pp. 764-766, PL LXXXV, figs. 3-6. (Described and discussed as a new species. The four specimens represented by figs. 3a-b, 4a-b, 6, and 5 are redrawn in this monograph, PI. LXXXI, figs. 2, 2d, 2e, and 2f-h, respectively.) Davidsonella squama Waagen, 1885, idem, pp. 766-767, PL LXXXVI, fig. 1. (Described and discussed as a new species. In 1891 [PL II, figs. 6a-b] Waagen figures the specimen represented by figs, la-b as Neoholus warthi. The specimen represented by figs, la-b is redrawn in this monograph, PL LXXXI, fig.' 2a.) Neoholus warthi Waagen, Oehleet, 1887, Manuel de conchyliologie, by Fischer, p. 1263, fig. 1012. (No text refer- ence. The two figures are copied from Waagen, 1885, PL LXXXIV, figs. 6 and 7.) Lakhmina linguloides (Waagen), Oehleet, 1887, idem, p. 1265, fig. 1015. (No text reference. The two figures are copied from Waagen, 1885, PL LXXXV, figs. 5 and 6.) Lakhmina linguloides Waagen, 1891, Mem. Geol. Survey India, Paleontologia Indica, 13th ser.. Salt Range Fossils, vol. 4, pt. 2, PL II, figs. 3a-c and 4a-c. (No text reference. Figs. 3a-b and 4a-b are copied from Waagen, 1885, PL LXXXV, figs. 3a-b and 4a-b, respectively; figs. 3c and 4c are copied from Waagen, 1885, PL LXXXV, figs. 6 and 5, respectively.) Neoholus warthi Waagen, 1891, idem, PL II, figs. 5-9. (No text reference. Figs. 5, 6a-b, 8a-b, and 8c are copied from Waagen, 1885, PL LXXXIV, fig. 4;. PL LXXXVI, figs, la-b; PL LXXXIV, figs. 5a-b; and PL LXXXIV, fig. 7; respectively. The specimen figured by Waagen, 1885, PL LXXXVI, figs, la-b, as Davidsonella squama is figured by him later, 1891, PL II, figs. 6a-b, as Neoholus warthi.) OBOLID^. 567 Neoholus wynnei Waagen, 1891, Mem. Geol. Survey India, Paleontologia Indica, 13th ser., Salt Range Fossils, vol. 4, pt. 2, PL II, figs. 10 and 11. (No text reference. Figs. 10 and 11 are copied from Waagen, 1885, PL LXXXV, figs. 2 and 1, respectively.) Lahhmina linguloides (Waagen), Hall and Clarke, 1892, Eleventh Ann. Rept. State Geologist New York for 1891, p. 234, figs. 243 and 244. (No text reference. Figs. 243 and 244 are copied from Waagen, 1885, PL LXXXV, figs. 5 and 6, respectively.) Neobolus warthi Waagen, Hall and Clarke, 1892, idem, p. 245, figs. 250 and 251. (No text reference. Figs. 250 and 251 are copied from Waagen, 1885, PL LXXXIV, figs. 6 and 7, respectively.) Lakhmina linguloides (Waagen), Hall and Clarke, 1892, Forty-fifth Ann. Rept. New York State Museum for 1891, p. 550, figs. 243 and 244. (No text reference. Figs. 243 and 244 are copied from Hall and Clarke, 1892a, figs. 243 and 244, p. 234.) Neobolus warthi Waagen, Hall and Clarke, 1892, idem, p. 561, figs. 250 and 251. (No text reference. Figs. 250 and 251 are copied from Hall and Clarke, 1892a, figs. 250 and 251, p. 245.) Lakhmina linguloides (Waagen), Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, p. 28, figs. 13 and 14. (No text reference. Figs. 13 and 14 are copied from Waagen, 1885, PL LXXXV, figs. 5 and 6, respectively.) Neobolus warthi Waagen, Hall and Clarke, 1892, idem, p. 84, figs. 39 and 40. (No text reference. Figs. 39 and 40 are copied from Waagen, 1885, PL LXXXIV, figs. 6 and 7, respectively.) Lahhmina linguloides (Waagen), Frech,_1897, additional plates inserted in 1897, in Lethsea geognostica, pt. 1, Leth^a palseozoica, atlas, 1876, PL I a, figs. 4a-b. (Figs. 4a and 4b are copied from Waagen, 1885, PI. LXXXV, figs. 5 and 6, respectively.) Neobolus warthi Waagen, Frech, 1897, idem, PL I A, figs. 5a-b. (Figs. 5a and 5b are copied from Waagen, 1885, PL LXXXIV, figs. 7 and 4, respectively.) The generic description embraces the characters of the species. By the courtesy of Dr. T. H. Holland, director Geological Survey of India, I have had the opportunity of studying the type material and thus of coming to an in- dependent opinion as to the genus and species. Waagen [1885, p. 758] states that the sur- face of the shell is perfectly smooth. I find that some of the specimens are worn nearly smooth, while others preserve concentric lines and strise of growth. The shells show the same variation of surface as do shells of Obolus that have lived on a sandy bottom and been more or less worn by the attrition of the sand. The second species of the genus, "Neobolus wynnei," differs from the types of Neoholus warthi, according to Waagen [1885, p. 760], only in having the surface strise more distinctly pre- served. This character does not appear to be of specific value, as there is considerable vari- ation in this respect among the type specimens of Neoholus warthi. The relations of Neoholus warthi and LaTchmina linguloides have been mentioned under observations on the genus Neoholus (page 565). The shell described as " Davidsonella squama" by Waagen [1885, p. 766] appears to be a dorsal valve of "Lakhmina linguloides." He figures it [1891, PL II, figs. 6a-b] as Neoholus warthi. I found some rock attached to the cardinal margin in such a manner as to give the effect of a low pointed apex. On clearing the rock away the apex was found to be marginal and the cardinal border the same as in the dorsal valves of "Lakhmina linguloides." The shell is the largest found at Jutana. It has a length of 13 mm.; width, 14.5 mm. The specific name was given in honor of Dr. H. Warth. Formation and locality. — Middle Cambrian: Lower portion of the "Neobolus beds" of the Khussak group, in purplish-colored, fine-grained, micaceous sandstones at the following localities [Waagen, 1885, p. 759]; (357c) near the fresh-water springs in a gorge above the salt mines at Kiura (Khewra); (357a) at Jutdna; and (357b) at Ch61 Hill; all in the Salt Range, India. A B Figure i7.— Neobolus warthi Waagen. A, Interior of dorsal valve showing area, median ridge, and thickening of the shell beneath the visceral area. On the right side the main vascular sinus is clearly shown. This drawing is from a cast of a dorsal valve in which the platform has not been developed. B, Outline of a platform, median ridge, and vascular sinuses in a dorsal valve, obtained by removing the outer shell by acid (X3). (See p. 565.) The specimens represented by figures 47A and 47B were collected in the Khussak group of the Middle Cambrian at Kiura (KhewTa), Salt Range, India. The specimen represented by figure 47A is shown in Plate I, fig. 4b, also, the present figure being the correct and later drawing from a cast made in a natural mold. The specimen from which the cast was taken is in the collection of the Geological Survey of India (Cat. No. 3/780). 568 CMIBRIAN BRACHIOPODA. SubfamUy BICIIN^ Walcott and Schucliert. Genus BICIA Walcott. o Bicia Walcott, 1901, Proc. U. S. Nat. Mus., vol. 23, pp. 676-678. (Described and discussed as below as a new genus.) Bicia Walcott, 190S, Smithsonian Misc. Coll., vol. 53, No. 4, PL XI, and pp. 142 and 144. (Classification of genus.) Shell subequivalve, moderately convex, longitudinally ovate, with the ventral valve sometimes subacuminate and the dorsal valve subcircular. Beak of both valves as now known terminates at the posterior margin. Surface marked by concentric and radiating striae. Shell substance unknown in an unaltered condition. Shell structure formed of a thin surface layer and numerous inner layers or lamellae more or less oblique to the outer layer. Area of the ventral valve usually on the plane of the edges of the valve, but in some instances it rises at a low angle; it is usually high and triangular in outline, but the apex may be rounded and the base curved forward at the median line; divided midway by a narrow pedicle furrow and again at each side by a narrow flexure line that extends forward and outward from the apex. Ai'ea of dorsal valve short; it appears in both of the known species to rise from the plane of the edges of the valve. Strife of growth subparallel to the base across the areas. The main vascular sinuses of the ventral valve are narrow and extend forward from the projecting center of the base of the area, gradually separating as they cross the visceral area and extend forward beyond the transverse center of the shell. In the dorsal valve they appear to separate more rapidly and to follow the outer margin of the central cavity, except in the second species. A narrow median septum is indicated in the dorsal valve on the crest of a strong median ridge. One of the striking features in both of the known species of this genus is the oblong oval boss (b) that is present in the ventral valve of most adult shells; it is situated each side of the forward projecting central portion of the area, with the larger axis extending forward and outward when the shell is subacuminate, and transverse when the shell is broadly rounded; in the dorsal valve of Bicia gemma (Billings) it is not so weU defined as in B. whiteavesi Wal- cott ; the boss (b) is bounded by the margin of the base of the area, the narrow elongate sulcus containing the marginal muscle scars and the base of the main vascular sinuses. In B. whit- eavesi it reaches its greatest development in both valves, resembling in position and surface characters the posterior occlusor scars of Pholidops implicata von Huene [1899b, p. 278, PI. X]. Somewhat similar bosses occur in the ventral valve of Oholella crassa (Hall) and Oholus apollinis Eichwald, but they are not developed to the extent they are in Bicia. They appear to occur only in those thick shells that have deposits of shell substance over the visceral area. The outline of the parietal scar in the ventral valve is well shown by Plate L, figure Ig; it incloses a heart-shaped visceral area in the ventral valve closely circumscribing the muscle scars; its general course in the dorsal valve i^ suggested by the position of the muscle scars. Five pairs of muscle scars have been observed. The rather large central scars (h) in the dorsal valve are placed close to the broad median ridge, a little back of the center; the small anterior laterals (j) are slightly in advance of the centrals on the median ridge, close to the median line; the transmedian scars (i) are almost under the edge of the area and near the outer margin; the outside (1) and middle (k) laterals are slightly in advance and farther out than the transmedian scars. The centrals, middle laterals, and outside laterals of the ventral valve are grouped in the narrow space on each side of the U-shaped forward-projecting portion of the visceral area (c, fig. 2) ; traces of individual scars have been seen, but they can not be separated so as to identify them; the transmedian (i) and anterior lateral (j) scars are close to the outer margin of the ventral valve and just in advance of the oblong boss in front and each side of the forward-projecting base of the area; umbonal and pedicle scars unknown, except what may possibly be a small umbonal scar in the dorsal valve of B. whiteavesi Walcott [PI. L, fig. 2e, at g]. a Prior to the definition of tlie genus Bicia the type species was described under the following genera: Oboklla Billings [1872a, p. 21S; lS72b, p. 357]. I Obolelta Hall and Clarke [1892c, pp. 69 and 71]. Obolella Walcott [1886b, p. 116; 1891a, p. 612]. | OBOLIDiE. 569 Type. — OioleUa gemma Billings. Second species: Bicia whiteavesi Walcott. Ohservations. — Bicia is a form that combines many of the characteristics of Oholella and Oiolus. It resembles Oholella in the arrangement of the muscle scars and main vascular sinuses of the interior of the valves. It differs in having a high area with an open pedicle groove in the ventral valve and an elevated ridge or boss in the back portion of the dorsal valve that in one species, B. whiteavesi, is very prominent. The ensemble of the dorsal valve of Bicia is unlike that of either Oholella or Oholus. Bicia with its thick shell, high area, deep central cavity (heart-shaped cavity of Mickwitz [1896, p. 71]), arrangement of visceral cavity, muscle scars, and vascular markings in the ventral valve, is a true Oholus of the 0. apolUnis Eichwald type; but in its more elongate outline, strongly striated surface, and in nearly aU details of the dorsal valve it is quite distinct. Of the two species now referred to the genus, B. gemma (BiUings) has an unusually thick shell and a very marked deposit of shell substance over the visceral area in the ventral valve, the posterior portion of the same area in the dorsal valve, and along its median line. In the second species there is a considerable deposit over the same area, with the exception of the median line, where the strong median ridge is absent. The generic name is derived from the town of Bic, Quebec, near which the type species was found. Bicia gemma (Billings). Plate L, figures 1, la-n. Oholella gemma Billings, 1872, Canadian Naturalist, 2d ser., vol. 6, No. 2, pp. 218-219; fig. 5, p. 217. (Described and discussed as a new species.) Oholella gemma Billings, 1872, Am. Jovir. Sci., 3d ser., vol. 3, p. 357, fig. 5, p. 3.55. (Described and discussed. Fig. 5 is copied from fig. 5 of the preceding reference.) Oholella gemma BilHngs, Walcott, 1886, Bull. U. S. Geol. Survey No. 30, pp. 116-117, PI. X, figs. 2, 2a-e. (Copies the original description, Billings, 1872a, pp. 218-219, and discusses species. The specimens represented by PI. X, figs. 2b, 2c, 2d, and 2e, are redrawn in this monograph, PL L, figs, li, Ij, Ik, and Ic, respectively.) Oholella gemma Billings, Walcott, 1891, Tenth Ann. Rept. U. S. Geol. Survey, p. 612, PI. LXXI, figs. 5, 5a-c, PI. LXXII, figs. 2 and 2a. (No text reference. Figs. 5, 5a-c are copied from Walcott, 1886b, PI. X, figs. 2, 2d, 2b, and 2c, respectively; PL LXXII, figs. 2 and 2a, are copied from Walcott, 1886b, PL X, figs. 2a and 2e, respec- tively.) Oholella gemma Billings, Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, pp. 69 and 71; fig. 30, p. 71; and PI. II, figs. 42-44. (Discussed under the genus Oholella. Fig. 30, p. 71, is copied from Wal- cott, 1886b, PI. X, fig. 2d; PL II, fig. 42, is drawn from the specimen figured by Walcott, 1886b, PL X, fig. 2a.) Bida gemma (Billings), Walcott, 1901, Proc. U. S. Nat. Mus., vol. 23, pp. 678-680. (Described and discussed as below.) General form ovate, with ventral valve subacuminate when the beak is extended, or obtusely acuminate when the beak is rounded; dorsal valve oval to subcircular in outline; the range of variation in the outline of the valves is shown by the figures on Plate L. The convexity of the valves is fairly strong and nearly the same in each where they are embedded in the same matrix. Surface of shell marked by numerous slightly irregular concentric stride and lines of growth, by fine radiating stride between stronger radiating lines, and on some sheUs by strongly developed, elevated, radiating striae; the radiating striae are often slightly irregular and interrupted, as shown by figure la. When the outer surface is partly worn away it is smooth, or the shell has a pecuUar surface formed by traces of the radiating, interrupted, or undulating stride (fig. Id). The concentric striae and lines of growth are shown on the outer surface of the inner layers of the shell and on the interior surface where rather strong radiating striae are often beautifully shown. The shell is unusually thick and strong for one so small; those from St. Simon and Troy appear to be calcareous and formed of one soHd layer; this is probabty owing to their condi- tion of preservation, as in a weathered specimen lamellae oblique to the outer surface are clearly shown, and indications of lamellse on the central and posterior portions point to the same shell structure as in Oholus and Oholella. 570 CMIBRIAN BRACHIOPODA. The ventral valves average about 5 mm. in length, the largest being 7 mm.; average width 4 mm., largest 5 mm. The dorsal A-alve is about one-fifth shorter than the ventral. The area f the ventral A'alve is usually on the plane of the margms of the valve, but in many specimens it rises at angles varying from 1° to 10°; it is high and narrow, somewhat as in Oholus (Schmidtia) acuminatus ;Mick^^•itz (PI. XIV, figs. 2, 2a) and divided midway by a strong, rounded, narrow pedicle furrow; the strife of growth are rather coarse and arch forward at the center and across the pedicle furrow, following the contour of the base of the area; the position of the flexure line is sometimes clearly sho^vn by a narrow depression. The area of the dorsal valve is short and easily escapes observation except in well-preserved shells; it sometimes has a slight central pedicle depression and often is only a short, almost smooth surface extending well out on the cardinal slopes of the valve. The muscle scars as far as determined are arranged as in Oholus. The umbonal and pedicle scars have not been observed. The elongate, oval central scars (h) are rather large in the dorsal valve and situated on each side of the strong median ridge about the middle of the valve; in the ventral valve they are crowded in with the scars of the middle and outside laterals; the anterior laterals (j) are barely discernible in one specimen of the dorsal valve as small oval dots on the central ridge a short distance in advance of the centrals; in the ventral valve they are close to the base of the area and near the outer edge of the shell; the middle and outside laterals in the ventral valve are situated in the trapezoidal area (c), but do not appear to be separable on the specimens in the collection; in the doreal valve they are well shown in advance of the transmedian scar (i). The latter (i) in the ventral valve is merged with the anterior laterals (j). Of the vascular markings the main sinuses of the ventral valve are about all that is clearly shown, although the position of the parietal scar is indicated in advance of the center of the shell (fig. Ig). One of the most strongly marked characters of the dorsal valve is the median ridge (mr); it varies in strength and outline in difl^erent shells, but is usually a promiaent feature; it extends to the frontal margin in most shells, but in some it narrows and is less prominent anteriorly. A few specimens show a slight depression crossing it just in front of the central scars, and one has two minute anterior lateral muscle scars directly on the ridge, the parietal scar passing across just in front of them. The thickened shell beneath the visceral cavity of the ventral valve is present in nearly all adult shells; it varies greatly in size, form, and thickness; in some valves it covers the entire area within the parietal scar (PI. L, figs. Ih and Ik), and in others only a portion (PI. L, fig. li). The thickening in the dorsal valve is along the posterior border of the central cavity; this is best shown in the cast (PI. L, fig. 1 1). The median ridge is also frequently more or less enlarged. Formation and locality. — Lower Cambrian : (2o) Limestone bowlders in conglomerate on shore at east entrance to harbor at Bic, Kimouski County; (2p) limestone on south side of the road a little west of Bic, and half mile (0.8 km.) west of the road leading to the wharf, Rimouski County; and (319b) limestone bowlders in conglomerate at St. Simon, Rimouski (?) County; all in the Province of Quebec, Canada. (392c [Billings, lS7'2a, p. 218]) At the Straits of Belle isle, Labrador. (32a) Limestone 0.75 mile (1.2 km.) west of Riders Mills on the Harlem Extension Raihoad, about 9 miles (14.4 km.) north-northeast of Chatham, Kiuderhook quadrangle (U. S. Geol. Survey), Columbia County; (27) even- bedded and conglomeratic limestones on the ridge in the eastern suburb of Troy, Rensselaer County; (29a) limestone 1 mile (1.6 km.) below the New York Central Raihoad depot at Schodack, Rensselaer County; and (2b) limestone just north of Beman Park, in the northeastern part of the city of Troy, Troy quadrangle (U. S. Geol. Survey), Rensselaer County; all in New York. BiCIA WHITEAVESI Walcott. Plate L, figures 2, 2a-e. Bieia whiteavesi Walcott, 1901, Proc. U. S. Nat. Mus., vol. 23, p. 680. (Characterized and discussed as below as a new species.) This species is associated with Bicia gemma (Billings) in a bedded limestone at Troy, New York. It differs from the latter, in the dorsal valve, in the absence of the median ridge; the presence of a broad area; in the presence in the interior of both valves of two large, OBOLID.^. 571 circular, scarlike spots, one on each side of the median line and just in front of the area, that recall in appearance and position the posterior adductor scars of Crania. The ventral valve is so much like that of B. gemma (Billings) that it is difficult to decide whether such shells as are represented by Plate L, figures 2a and 2b, should not be referred to B. gemma. There is a gradual transition in form and character of the interior of the ventral valve between the extremes represented in B. gemma bj' figures Ih and li, through figures If, Ig, Ik, 2a, and 2b, to the extreme form of B. whiteavesi, figure 2c. If it had not been for the bosses in figure 2c, and the doreal valve, figure 2e, associated with it, I would have hesitated to refer it to a distinct species. The specific name is given in honor of Prof. J. F. Whiteaves, of the Geological Survey of Canada. Formation and locality. — Lower Cambrian: (2b) Limestone just north of Beman Park, in the northeastern part of the city of Troy, Troy quadrangle (U. S. Geol. Survey), Rensselaer County, New York. Genus DICELLOMUS HaU.o Bicellomus Hall, 1873, Twenty-third Ann. Rept. New York State Gab. Nat. Hist., p. 246. (Characterized as a new genus.) Schmidtia Zittel (in part) [not Volborth], 1880, Handbuch der Palseontologie, Bd. 1, Abth. 1, p. 665. (Doubtfully places DiceUotnus as a synonym of Schmidtia.) Oholella Billings, Hall and Clarke (in part), 1892, Eleventh Ann. Rept. State Geologist New York for 1891, pp. 240-241. {Dicellomus is included with Oholella as a synonym.) Oholella Billings, Hall and Clarke (in part), 1892, Forty-fifth Ann. Rept. New York State Museum for 1891, pp. 556-557. (Copy of preceding reference.) Oholella Billings, Hall and Clarke (in part), 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, pp. 66-73, espe- cially pp. 72-73. (Dicellomus is discussed as a synonym of Oholella.) Bicellomus Hall, Walcott, 1899, Mon. U. S. Geol. Survey, vol. 32, pt. 2, p. 446. (Discussed, part of the paragraph being copied below, see p. 572.) Dicellomus Hall, Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 312-313. (Described and discussed essentially as below.) Dicellomus Hall, Grabau and Shimer, 1907, North American Index Fossils, vol. 1, p. 189. (Described.) Dicellomus Hall, Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 4, PI. XI, and pp. 142 and 144. (Classification of genus.) Shell small; general form ovate to subsemicircular, biconvex, with apices marginal. Sur- face of outer shell finely punctate in aU species where it is preserved uninjured. Interior or middle lamellse marked by radiating striae and minute punctse; inner surface finely punctate. The shell is thick in all the species now known, and is buUt up of a thin, outer, scabrous layer, numerous inner layers or lamellse, and a thin inner layer. Shell substance apparentlj calcareo- corneous. The interior of the ventral valve (PI. LII, figs. Ic, Id) shows a short area with a median pedicle groove; an elongate visceral area; well-marked main vascular sinuses; large, composite scars (cl) where the posterior muscles, i. e., transmedian and outside and anterior laterals, were attached; and a short shelf that extended into the valve from each side of the pedicle groove. This extension appears to correspond to the dental plate in the articulate brachiopods, and it has a shght thickening at the anterolateral margin that suggests a short tooth. In material received from Prof. W. A. Finkehiburg from Hudson, Wisconsin, I worked out several interiors of the ventral valve and found in all of them more or less of the remains of a lining of the pedicle a The synonymy tor this genus does not give a complete record of the various genera under which the species now included in Dicellomuf were formerly placed; it gives only those references in which the genus is discussed or described. To complete the record the tollowing mere generic references are listed: Oiolus Owen [1852, p. 501]. Lingula Hall [1S61, p. 24]. Oholella Billings [1861b, p. 7; lS61c, p. 946]. Lingula Hall [1862, p. 435]. Obolella Billings [lS62c, p. 421 ; 1862d, p. 67; lS62e, p. 218]. Obolella Meek and Hayden [1862, p. 435]. Obolella Hayden [1862, p . 73]. Lingula 'iVTiitfleld [1862, p. 136]. OboleUa f HaU [1863, p. 133]. Lingulepis Meek and Hayden [1865, p. 3]. Obolella Meek and Hayden [1865, p. 4]. Obolella/ HaU [ 887, p. 112]. Obolus Whitfield [1875, p. 103]. Obolus? 'Whitfield [1880, p. 338]. OboleUa Whitfield [1880, pp. 339 and 340], Obolella Walcott [18S6b. p. 111]. Obolella Schuchert [1897, p. 275]. Dicellomus Walcott [1901, p. 673; 190Sd, p. 77]. 572 CAMBRIAN BRACHIOPODA. tube tliat extended on each side above the plane of the cardmal area so as to form a concave phite similar to the posterior portion of the sponilylium in SyntropJiia (PI. C'll, fig. 6f). If the sides of the plate were extended farther and united about the pedicle, a tube would result similar to that of OboleUa (PI. LV, figs. If and Ih), and ultimately to that of Botsfordia (PI. LVII, figs. 4c and 4g). Tliis plate in Dicellomus, while suggesting a spondylium, is more nat- urally interpreted as the beginning of a pedicle tube. The Ulterior of the dorsal valve has a well defined but very narrow area in one species, D. politus (Hall), that is hollowed out so as to form a shallow groove on each side, apparently for the reception of the short tooth of the ventral A^alve. No good posterior margins of the valve could be found of the other species of the genus. The composite scar is large, and in one shell it is subdivided into three small scars that were the points of attachment of the trans- median and outside and middle laterals. The central and anterior lateral scars are arranged as in Oiolus; the centrals are large and located on the sides of the visceral area; the anterior laterals are small and are located at the anterior end of the visceral area. Type. — Lingida polita Hall. Observations. — When referring to Dicellomus in 1899 I said [1899, p. 446]: When proposing that the genus Dicellomus include OboleUa polita, Professor Hall [1873, p. 246] stated that the grooving or emargination of the apices of both valves and the thickening of the edges of the shell on each side below the apex, together with the form and character of the muscular impressions, would separate the species from OboleUa. Again, Messrs. Hall and Clarke [1892c, p. 72] gave a fuller description of Dicellomus politus, but owing to the poor character of the material they did not feel confident that it should be recognized as generically distinct from OboleUa chromatica. Material now in the collections of the United States Geological Survey clearly shows that Professor Hall's provisional conclusion was correct, and that Dicellomus politus is generically distinct from OboleUa chromatica. The presence of the large, composite, cardinal muscle scars in each valve suggests that a search be made for a foraminal opening, as in OboleUa, Linnarssonella, and Acrotreta. No trace has been found externally, and the interior of the ventral valve does not show evidence of it, except in the pedicle plate. Dicellomus appears to include characteristics of Obolus and OboleUa, and the presence of incipient dental plates, teeth, and dental grooves suggests an articulate shell. Dicellomus appalachia Walcott. Plate LIll, figures 4, 4a-g. Dicellomus appalachia Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 314. (Described and discussed as below as a new species.) This shell has been identified with D. politus (Hall) in the preliminary studies of the genus Dicellomus. I find that while it has the same type of shell structure and general form, it differs in being less elongate proportionallj^ and in the details of the form and positions of the muscle scars and vascular markings of the interior of the valve; it difl^ers in the latter respect from D. nanus (Meek and Hayden). The outer thm layer has a dull, finely roughened surface that is minutely punctate. When the outer layer is exfoliated the surface of the layer beneath is highly poUshed and marked by exceedingly fine radiating and concentric strise and lines of growth. The interior of the dorsal valve shows the large central muscle scars with the minute anterolateral scars almost in contact with them. A composite scar (cl, PI. LIII, fig. 4d) shows the separate points of attachment of the transmedian (i), outside lateral (1), and middle lateral (k) scars. The variation in the length of the visceral cavity of the dorsal valve, as shown in Plate LIII, figures 4d to 4g, is very great, and it may be that figures 4f and 4g belong to another species. This species occurs in great abundance in both limestones and shales. It is the Appa- lachian representative of the widely distributed D. politus of the interior of the continent, hence the specific name. Formation and locality. — Middle Cambrian; (2z) Nolichucky (?) shale [Campbell, 1899, p. 3], near Shipley Ferry, 0.75 mile (1.2 km.) northwest of Bethany Chapel, northeastern corner of the Roan Mountain quadrangle (U. S. Geol. Survey); (2z') shales in the Honaker limestone [Campbell, 1899, p. 3], at Wallace switch, about 5 miles (8 km.) northeast of Bristol, Bristol quadrangle (U. S. Geol. Survey); and (374c) sandy shale (Nolichucky?) [Campbell, 1899, OBOLIDiE. 573 p. 3], 8 miles (12.8 km.) northeast of Shipleys, near the line between the Roan Mountain and Bristol quadrangles (U. S. Geol. Survey); all in Sullivan County, Tennessee. (103a) Upper part of the second shale south of the ridge of sandstone in the Rome formation ("Town Knobs"), on the road from Rogersville to Dodson Ford, near the line between the Morristown and Greeneville quadrangles (U. S. Geol. Survey); (102) Rogersville shale just south of road, one-half mile (0.8 km.) southwest of Rogersville, on the road to Melinda Ferry [Keith, 1896a, areal geology sheet]; (104) shale in railroad cut 0.5 mile (0.8 km.) from Roo-ers- ville on the road to Holston River, near the line between- the Morristown and Greeneville quadrangles (U. S. Geol. Survey); (124a) shale (Nolichucky?) overlying the limestone which rests on the Rogersville shale, on Big Creek, southeast of Harlan Knob, 4 miles (6.4 km.) northeast of Rogersville [see Keith, 1905, p. 4, and areal geology sheet]; and (374b) shale 1.25 miles (2 'km.) fi-om Rogersville, near the line between the Morristown and Greeneville quadrangles (U. S. Geol. Sui'vey); all in Hawkins County, Tennessee. (107) IJmestone in Bull Run; and (107b) shales in railroad cut in Bull Run; both northwest of Copper Rido-e [Keith, 1896b, areal geology sheet], 11 miles (17.6 km.) northwest of Knoxville, Knox County, Tennessee. (11a) Sandstone between First and Armstrong creeks, in the southeast corner of the Maynardville quadrangle (U. S. Geol. Survey), Union County; (117c) shale at Buckingham Ford on Hollis Creek, 5 miles (8 km.) south- east of Greeneville, Greene County; (374a) limestones 2 miles (3.2 km.) south of Coal Creek, Anderson County; and (119) limestone in various localities in Jefferson and Hawkins counties; all in Tennessee. (16) Conasauga limestone, Blountsville Valley, Blount County; (89) limestone in Murphrees Valley, Blount County; (90a) shales at Cedar Bluff, Cherokee County; (90b) Conasauga limestone, in cut on Louisville and Nash- ville Railroad, near Woodstock, Bibb County; (144c) limestone near the top of the beds exposed nearN. K. Burns's barns, near Swansea (Viola), Blount County; and (91) Conasauga ("Coosa") shale, at Cedar Bluff, Cherokee County; all in Alabama. (47h) Shales on Wolf Creek, 6 miles (9.6 km.) below Rocky Gap, Bland County, Virginia. DiCELLOMUs NANUS (Meek and Hayden). Plate LIII, figures 1, la-1, 2, 2a, 3, 3a-d. Obolella nana Meek and Hayden, 1862, Proc. Acad. Nat. Sci. Philadelphia for 1861, vol. 13, pp. 435-436. (Described and discussed as a new species.) Obolella nana Meek and Hayden, Hayden, 1862, Am. Jour. Sci., 2d ser., vol. 33, p. 73, figs, la-b and 2a-b. (Char- acterized and discussed. The two specimens represented by figs. 2a and 2b are redrawn in this monograph, PL LIII, figs. 2a and 2, respectively.) Obolella nana Meek and Hayden, Billings, 1862, Geol. Survey Canada, Paleozoic Fossils, vol. 1, pp. 67-68. (Original reference. Meek and Hayden, 1862, pp. 435—436, copied.) Obolella nana Meek and Hayden, 1865, Smithsonian Contrib. Knowl., No. 172, Paleontology Upper Missouri, pt. 1, p. 4, PL I, figs. 3a-d. (Described and discussed. Figs. 3a-b and 3c-d are copied from Hayden, 1862, p. 73, figs. 2a and 2b, respectively.) Obolella nana Meek and Hayden, Whitfield, 1880, U. S. Geog. and Geol. Survey Rocky Mtn. Region, Rept. Geoloo-y and Resources Black Hills of Dakota, by Newton and Jenney, pp. 340-341, PL II, figs. 14-17. (Copies the description given by Meek and Hayden, 1865, p. 4, and discusses species. Fig. 17 is copied from Meek and Hayden, 1865, PL I, fig. 3d.) Obolella nana Meek and Hayden, Walcott, 1886, Bull. U. S. Geol. Survey No. 30, p. 111. (Discussed.) Obolella nana Meek and Hayden, Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, pp. 69-70. (Discussed.) Dtcellomus nanus (Meek and Hayden), Walcott (in part), 1899, Mon. U. S. Geol. Survey, vol. 32, pt. 2, p. 447, PI. LX, figs. 3a-d (not fig. 3). (Synonymy and new localities given. Figs. 3b and 3d are drawn from the specimens figured by Hayden, 1862, p. 73, figs. 2a and 2b, and are redrawn in this monograph, PI. LIII, figs. 2a and 2, respectively. The specimens represented by figs. 3a and 3c are not figured in this monograph. The specimen represented by fig. 3 is referred in this monograph to Lingulella desiderata.) Dicellomus nanus (Meek and Hayden), Walcott, 1905, Proc. IT. S. Nat. Mus., vol. 28, pp. 314-315. (Described and discussed essentially as below.) The principal characters of this species are the same as Dicellomus politus (Hall). The two forms differ exteriorly in D. nanus being more convex on the umbones and less elongate. The interior of the ventral valve shows a less elongate visceral area, a relatively larger com- posite muscle scar (cl); the interior of the dorsal valve of D. nanus has a much larger com- posite muscle scar and a broader visceral area with the central muscle scar farther from the median line. One of the types of D. nanus is the interior of a ventral valve (PL LIII, fig. 2), on which there is a subtriangular depression (c) that appears to have been the path of advance of the areas, on each side of the median space, in which the central muscle, and the middle and outside 574 CMIBRIAN BRACHIOPODA. lateral jnuscles, were attached. Another shell from the Bighorn Mountains shows something of the same character (PL LIII, fig. ll). The area of the ventral valve is short, and divided midway by a shallow pedicle furrow; area of dorsal valve unknown. The exterior of the shell appears to be smooth and slightly polished, except for fine con- centric striis and lines of growth and what appear to be scattered punctse. The average size of the adult shells is from 3 to 4 mm., the length and width usually being nearly the same. The exact horizon of the type specimen is unknown. It occurs in a somewhat friable, purplish sandstone, unlike any beds in tlie Middle Cambrian Deadwood formation that I met with. The specimens from the limestones of the Bighorn Mountains, etc., appear to belong to the Upper Cambrian. Formation and locality. — Ordovioian: (302v) Sandstones 2 miles (3.2 km.) west of the main summit of Buffalo Fork Peak [St. John, 1877, pp. 468 and 469 and map opposite p. 324 (near station XLIX)], about 25 miles (40 km.) east of Jackson Lake, Uinta County, Wyoming. Upper Cambrian: (152a) West side of Dry Creek below Pass Creek; and (158a) limestone north of East Gallatin River near Hillsdale; both in the Threeforks quadrangle (U. S. Geol. Survey), Gallatin County, Montana. (302u) Upper limestone of the Deadwood formation, north of Cheever's ranch, on the summit of the Bighorn Mountains, Wyoming. Middle Cambrian: (170) Sandstone about 10 miles (16.1 km.) south-southeast of Bald Moimtain, Bighorn Moun- tains; (302m^ middle of shale above lower sandstone on Billy Creek in the Bighorn Mountains; (302y) sandstone on Johnson Creek, Bighorn Mountains; and (302b) limestones near Crowfoot Ridge, Gallatin quadrangle (U. S. Geol. Siirvey), Yellowstone National Park; all in Wyoming. (302z) Limestone on Mill Creek, near Landusky, Little Rocky Mountains, Chouteau County, Montana. (355) Sandstones on Red Canyon Creek, southwest side of Black Hills; and (355d) sandstone in the Black Hills; both in South Dakota. .,-, (llj) Basal part of Bonneterre limestone. Mine Lamotte, Madison County; and (11m) drill cores of limestone'at horizons 10 and 20 feet (3 and 6 m.) above the Lamotte sandstone, St. Francois County; both in Missouri. DiCELLOMUS PARVUS Walcott. Plate LXXXIX, figures 11, lla-d. Dicellomus parvus Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 315-316. (Described and discussed as below as a new species.) General form ovate, with the ventral valve subacuminate and dorsal valve broad oval to subcircular. Valves moderately convex. Surface of outer shell dark and polished; it is marked, when not abraded, by fine, clearly defined, concentric striss and occasional lines of growth. The largest ventral valve has a length of 2.5 mm. and a width of 2 mm. The shell is strong but not thick. Shell substance apparentlj'- calcareocorneous. Ventral valve uniformly convex, except that the slopes toward the cardinal margins are more abrupt than elsewhere; apex appears to be marginal. The interior of the valve shows a short, low, median ridge in the center of the visceral cavity; on each side, and a little in front of the end of the median ridge are the trapezoidal areas for the attachment of muscle scars; rather small, composite cardinal muscle scars occur close to the cardinal margins. Dorsal valve somewhat less convex than the ventral; apex marginal. The interior of the valve shows well-defmed composite cardinal muscle scars, a narrow median septum, and a faintly impressed main vascular sinus that curves outward and forward at about one-third the distance from the outer margin to the median septum; the central muscle scars are small and situated back of the center of the valve on each side of a low median swelling on which the median septum occurs; the position of the anterior lateral muscle scars is indicated at the end of the median septum a little in advance of the center of the valve. Ohsen'ations. — This minute shell has the generic characters of Dicellomus politus (Hall), but it differs specifically in its minute size and the positions of the muscle scars in the dorsal valve. Formation and locality.— Middle Cambrian : (C6) Thin slobby limestone in the upper shale member of the Kiulung group [Blackwelder, 1907a, pp. 37 and U {2d list of fossils), and fig. 10 {bed n), p. SS], Z.5 miles {4 km.) southwest of OBOLID^. 575 Yenckuang, Sintai district, Shantung; and (C32) a fine-grained bluish-black limestone bowlder believed to have come from the lower part of the Kisinling limestone [Blackwelder, 1907b, p. 272], collected in river drift 1 mile (1.6 km.) south of Chonpinghien, on Nankiang River, eouthern Shensi; both in China. DiCELLOMUS PECTENODDES OVllitfielcl). Text figures 48A-B; Plate LII, figures 6, 6a-c. Obolus pectenoides Whitfield, 1875, Kept. Reconnaissance Black Hills of Dakota, by Ludlow, p. 103, unnumbered plate, figs. 1-3. (Described and discussed as a new species.) Obolus f pectenoides Whitfield, 1880, U. S. Geog. and Geol. Survey Rocky Mtn. Region, Kept. Geology and Resources Black Hills of Dakota, by Newton and Jenney, pp. 838-339, PI. II, figs. 18 and 19. (Described. The specimens represented by figs. 18 and 19 are redrawn in this monograph, PI. LII, figs. 6 and 6a, respectively.) Obolella pectenoides (ViTiitfield), Schuchert, 1897, Bull. IT. S. Geol. Survey No. 87, p. 275. (Merely changes generic reference.) Dicellomus pectenoides (^Tiitfield), Walcott, 1901, Proc. U. S. Nat. Mus., vol. 23, p. 673. (Merely changes generic reference.) Dicellomus pectenoides C^Tiitfield), Walcott, 1905, idem, vol. 28, p. 316. (Characterized.) This is the largest shell of the several species of the genus. A ventral valve 9 mm. long has a width of 11 mm. All that is known of the structure of the shell indicates that it was like D. politus (Hall) (PL LII) and D. nanus (ileek and Hay den) (PI. IJII). This siiecies differs from all other described species b}" the anterior posi- tion of the central muscle scars of the dorsal valve, its larger size, and the thickening beneath the visceral cavity of the ventral valve. Area of ventral valve short and mucli like that of D. nanus (PI. LIII, fig. Ic). Specimens from Eau Claire, Wisconsin, show a tliickenlng of the shell beneath the visceral cavity of the ventral valve not unlike „ ,. _. „ , ., ,w),-*fl i^\ ^ n t r ■ _ •' _ _ FiGUKE iS.—Dicdlomus pectenoides (Whitfield). A, Cast of in- that of Elkania desiderata (Billings) (PI. IjI, fig. la). tenor of ventral valve from Locality 78a, "St. Croix sand- The interior of the dorsal valve is quite dissimdar fZ!'.' '4 T',""'^"',' ""^™°^'" '''• f' "";'■ "!"" ^f • ^°- 1 51909). B, Cast of interior of dorsal valve from Locality 100, in the two species. "St. Crolx sandstone" at Menomonie, Dunn County, Wis- consin (IT. s. Nat. Mus. Cat. No. 51910). v, Visceral cavity; Formation and locality. — TTpper Cambrian : (151a) Lime- vs, main vascular sinuses; h, central muscle scars, stone in point overlooking Chum Canyon, on the west side of the Bridger Range; and (158) limestone north of East Gallatin River near Hillsdale, Threeforks quadrangle (U. S. Geol. Survey); both in Gallatin County, Montana. (78a) "St. Croix sandstone" in the topmost quarry on Mount Washington, near Eau Claire, Eau Claire County; and (100) "St. Croix sandstone" near Menomonie, Dunn County; both in Wisconsin. Middle Cambrian: (355b) Sandstone in the Deadwood formation on Castle Creek, on the west side of the Black Hills; and (164) sandstone in the Deadwood formation in the cliffs on the east side of the valley near Deadwood, Black Hills; both in South Dakota. (355c [Whitfield, 1S75, p. 10-3]) Sandstone on French Creek, Black Hills, South Dakota. Dicellomus politus (Hall). Text figures 16A-B, page 314; 49A-B, page 576;a Plate LII, figures 1, la-k, 2, 2a-i, 3, 4, 4a, 5, 5a-b. Obolus appolinusf Owen (not Eichwald), 1852, Rept. Geol. Survey Wisconsin, Iowa, and Minnesota, Appendix, p. 501, PL I B, figs. 9, 11, 15, and 20. (Occurrence mentioned.) Lingula polita Hall, 1861, Rept. Supt. Geol. Survey Wisconsin, p. 24. (Described and discussed.) Obolella sp. 3 Billings, 1861, Geol. Survey Canada, Paleozoic Fossils, vol. 1, p. 7. (Characterized.) Obolella sp. 3 Billings, 1861, Report on the Geology of Vermont, vol. 2, p. 946. (Copy of preceding reference.) Lingula ? polita Hall, 1862, Rept. Geol. Survey Wisconsin, vol. 1, p. 435, fig. 1, p. 21. (Generic reference discussed.) Obolella polita (Hall), Billings, 1862, Am. Jour. Sci., 2d ser., vol. 33, p. 421. (Note on the dates of publication of the references cited above. Hall, 1861, p. 24, and Billings, 1861, p. 7.) Obolella sp. 3 Billings, 1862, Report on the Economic Geology of Vermont, by Hager, p. 218. (Copy of Billings, 1861b, p. 7.) Lingula polita HaU, Whitfield, 1862, Am. Jour. Sci., 2d ser., vol. 34, p. 136. (Note on the date of the first reference to Lingula polita.) Obolella f polita Hall, 1863, Sixteenth Ann. Rept. New York State Cab. Nat. Hist., pp. 133-134, PL VI, figs. 17-21. (Described and discussed.) a Text figures 16A-B and 49A-B are the same. 576 CAMBRIAN BRACIIIOPODA. DiceUo7nus politiis (Hall), Walcott, 1905, idem, pp Linc/uhpis prima Meek and Hayden, 1865, Smithsonian Contrib. KnowL, No. 172, Paleontology Upper Missouri, pt. 1, p. 3, PL I, figs. 2a-b. (Described and discussed as a new species. The specimen represented by figs. 2a and 2b is redrawn in this monograph, PL LII, fig. 2h.) Obolella ? polita Hall, 1867, Trans. Albany Inst., vol. 5, pp. 112-113, PL I, figs. 17-21. (Text and figures copied from Hall, 1863, pp. 133-134, PL VI, figs. 17-21.) Dicellomm polita Hall, 1873, Twenty-third Ann. Kept. New York State Cab. Nat. Hist., p. 246. (Changes generic reference.) Obolella polita (Hall), Whitfield, 1880, U. S. Geog. and Geol. Survey Rocky Mtn. Region, Rept. Geology and Resovirces Black Hills of Dakota, by Newton and Jenney, pp. 339-340, PL II, figs. 12 and 13. (Described and discussed. The specimen represented by fig. 13 is redrawn in this monograph, PL LII, fig, 2g; fig. 12 is not.) Obolella polita (Hall"), Walcott, 1886, Bull. U. S. Geol. Survey No. 30, p. 111. (Discussed.) Obolella polita (Hall), Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, pp. 72 and 73, PL II, figs. 37-il. (Discussed as a species of Dicellomus, but the use of that term is held in abeyance until the species shall have been proven generically distinct from Obolella. Figs. 40 and 41 are copied from Hall, 1863, PL VI, figs. 20 and 21.) Dicellomus politus (Hall), Walcott, 1899, Hon. V. S. Geol. Sm'vey, vol. 32, pt. 2, pp. 443 and 446, PL LX, figs. 4 and 4a. (Discussed, establishing the generic distinctness of Dicellomus. The specimens represented by figs. 4 and 4a are redrawn in this monograph, PL LII, figs. Ij and Ic, respectively.) Dicellomus politus (Hall), Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 313. (Copy of text referred to in preceding reference.) 316-318. (Described and discussed as below, although some changes and additions have been made.) Dicellomus politus (Hall), Grabau and Shimer, 1907, North American Index Fossils, vol. 1, pp. 189-190, fig. 224, p. 190. (Described. The three figures in fig. 224 are J4S "-■^8aEa»fc^a», copied from Hall, 1863, PL VI, figs. 17, 20, and 21.) General form ovate, with the ventral valve subacuminate; biconvex, the ventral valve usually more convex than the dorsal. Surface smooth as the specimens usually occur, but a few examples \ B show that there is a thin outer layer covered with fine papUlee and punctre that appear to be placed on very fine, more or less inosculating ridges. Concentric lines of growth of varying strength show on the outer surface, also on the various inner laj^ers or lamellas. When the outer layer is exfoliated or worn off by attrition of the sand, the surface of the inner layer is marked by radiating strife and concentric lines of growth that are a marked feature of the species. The radiating strife may be uniform m size, or with 4 to 6 very fuie strife between two stronger elevated strise. Inner surface smooth to the eye, but a strong lens shows that it is finely punctate, with exceedingly fine, irregular, raised lines all over the surface. The intermediate layer is more coarsely and irregularly punctate. The shell is thick, and is built up of a thin, scabrous, outer layer, a middle layer made up of several highly polished lamellee, and a thin inner layer. The numerous inner lamellae are oblique to the outer surface over much of the shell, and thus give it thickness. Shell sub- stance calcareocorneous. The usual length of the ventral valves from Wisconsin is about 6 mm., width 5 mm., with the same width and length for the dorsal valve. Specimens from the Black Hills average a trifle larger than those from Wisconsin. Ventral valve with a uniform convexity over the central portions, from which the surface slopes gently to the margins. Apex nearly if not quite margmal. Casts of the interior indi- cate a short cardinal area that extends out on the cardinal margins of the shell and appears to merge into the margins. On each side of the pedicle furrow a thin plate or shelf (sh) extended into the valve on the plane of the margins of the shell. Some of the casts indicate that these Figure 49.— Dicellomus politus (Hall). A, Interior of ventral valve (fsp, pseudospondylium or pedicle plate; i, transmedian scars; j, anterolateral scars; v, visceral cavity; vs, main vas- cular sinuses). B, Posterior portion of the interior of a ventral valve, showing a strongly developed area (fsp, pseudo- spondylium or pedicle plate; a, inside section of area; f, flexure line; a', outside section of area). The specimens represented by figures 49A and 49B are from Locality 79s, Upper Cambrian "St. Croix sandstone" at Hud- son, Wisconsin (tT. S. Nat. Mus. Cat. Nos. 51917a and 51917b, respectively). The same figures are reproduced on page 314. OBOLID^. 577 plates had a projecting boss or tooth that articulated in a rude manner with the depressions on the posterior, flattened, inner margin of the dorsal valve. If this interpretation is correct the teeth and plates correspond to the teeth and dental plates of the articulate brachiopods and the plates may mark the beginning of a spondylium. A number of interiors from Hudson, Wisconsin, show a concave plate in the pedicle furrow, the edges of which rise above the plane of the cardinal area; this plate is evidently the begin- ning in Dicellomus of the pedicle tube, as shown in Oholella (PI. LV, figs, le. If, and Ih). In some shells the plate appears to extend into the shell beyond the anterior margin of the car- dinal area and it then has the appearance of a small spondyUum. I think, however, that it is only the secretion of shelly matter about the pedicle and not connected with the development of a spondylium; the latter is indicated by the extension of the toothlike processes already referred to. The posterior lateral, transmedian, and anterior lateral muscles were undoubtedly attached within the area of the composite scar (cl) (PI. LII). The visceral area and pos- terior portions of the main vascular sinuses are weU outlined, but no muscle scars or details of the vascular system have been preserved in the material studied. Dorsal valve most convex back of the center. Apex marginal. The interior of the valve shows shallow depressions in the flattened posterior margin (a) that suggest dental cavities for the reception of the dental projections of the ventral valve. The central muscle scars (h) are shown a little back of the center of the valve, where a low median ridge bifurcates (PI. LII, fig. li). In some shells a sharp median septum is shown, also narrow main vascular sinuses. Observations. — The reference to this species of the specimens from the siliceous shale at Helena is rather doubtful, as the shells are compressed and distorted. (See PI. LII, figs. 4 and 4a.) Shells agreeing with D. politus m all points available for comparison occur in the basal, probably Middle Cambrian, sandstone beneath the great limestone series of Ai-izona. The material is abundant and preserved very much in the same condition as that from the Deadwood formation of the Black HUls of South Dakota. In sandstones in the basal part of the Upper Cambrian Reagan sandstone in Oklahoma a few shells were found that appear to be identical with D. politus. They have the elongate form of that species, which is unknown in any other species of the genus. In the collections made by the Fortieth Parallel Survey there are specimens so closely resembling D. politus that they are identified as such, although the dorsal valve is rather transverse. Dicellomus politus differs from D. nanus (Meek and Hayden) and D. pedenoides (Whit- field) in being more elongate, also in the details of the interior markings of the valves. From D. appalachia Walcott it differs in interior markings, and, as specimens average, in being more elongate. Formation and locality. — Upper Cambrian: (83b) "St. Croix sandstone" along the railroad track near Taylors Falls, Chisago County; (97 and S97x) "St. Croix sandstone" at Reads Landing, foot of Lake Pepin, Wabasha County; (339i) [Owen, 1852, desc. of PI. IB] sandstones of Flh of Owen's section, below Mountain Island, in Mississippi River, nearly opposite the old mouth of Black River; and (98a) "St. Croix sandstone" at Marine Mills, on St. Croix River, Washington County; all in Minnesota. (78a) "St. Croix sandstone" in the topmost quarry on Mount Washington, near Eau Claire, Eau Claire County; and (98 and 98x) "St. Croix sandstone" near Eau Claire, Eau Claire County; (79s) "St. Croix sandstone" in bluff near Hudson, St. Croix County; (328c) "St. Croix sandstone" at Alma, Buffalo County; (83) "St. Croix sandstone" near Trempealeau, Trempealeau County; (100a) "St. Croix sandstone" at Ettrick, Trempealeau County; (80) "St. Croix sandstone" 0.66 mile (1.1 km.) southwest of the railway depot, Menomonie, Dunn County; and (100) "St. Croix sandstone" near Menomonie, Dunn County; all in Wisconsin. (128a) Shales on the Louisville and Nashville Railroad, 1.5 miles (2.4 km.) southeast of Cog Hill, near the line between Polk and McMinn counties, Tennessee. 62667°— vol 51, pt 1—12 37 578 CAIVIBRIAN BRACHIOPODA. (9x) Sandstones lying between beds of quartzite underlying the 300 feet of limestone at the top of the Reagan sandstone, SW. } sec. 17, T. 4 N., R. 12 W., about 11 miles (17.7 km.) northwest of Fort Sill, Comanche County, Oklahoma. Tipper? Cambrian: (358a) Siliceous limestone on Ash Creek, in Pinal County, Arizona. Middle Cambrian: (84 and 84f) "St. Croix sandstone" at Dresbach, opposite the mouth of Black River, Winona County; (339e) "St. Ci-oix sandstone" on Mountain Island, in Mississippi River, just above the mouth of Trem- pealeau River; and (84s) "St. Croix sandstone" near Dakota, Winona County; all in Minnesota. (79x) "St. Croix sandstone" near the flour mill on Beaver Creek, north of Galesville; and (328g) "St. Croix sand- stone," Wisconsin shore of Mississippi River, near Trempealeau; both in Trempealeau County, Wisconsin. (167) Sandstone beneath limestone and resting on pre-Cambrian "slates, schists, and pegmatites" in bluff 9 miles (14.4 km.) west of Custer, Black Hills; (355e) sandstone in the central part of the Black Hills; and (355) sand- stones in Red Canyon " Creek , southwest side of the Black Hills; all in South Dakota. (Hm) Drill cores of limestone in the Bonneterre limestone at horizons 10 and 20 feet (3 and 6 m.) above the Lamotte sandstone, at Flat River, St. Francois County, Missouri. (329b) Thin-bedded limestone collected by the 'Wheeler Survey in Utah. (5k) Limestone in Jleagher County, on the road to Wolsey, about 1 mile (1.6 km.) south of the divide at the head of Sawmill Creek, and 8 miles (12.8 km.) south of Neihart, Little Belt Mountains quadrangle (U. S. Geol. Sur- vey), Cascade County; (302k) limestone near Gallatin, Threeforks quadrangle (U. S. Geol. Survey), Gallatin County; (302s) b dark siliceous shale in a quarry in Last Chance Gulch, south slope of Mount Helena, 1.5 miles (2.4 km.) south of Helena, Lewis and Clark County; and (340f) lowest beds exposed at the mouth of Bear Creek, Little Belt Mountains; all in Montana. DiCELLOMUS PEOLIFICUS Walcott. Plate LXXXIX, figures 10, lOa-b. Dicellomus prolificus Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, p. 77, PI. VIII, figs. 3 and 3a. (Char- acterized and discussed as below as a new species. Figs. 3 and 3a are copied in this monograph, PL LXXXIX, figs. 10 and 10b, respectively.) This species differs from Dicellomus politus (Hall), to which it appears to be most nearly related, by the greater convexity of the ventral valve, its higher umbo, and, in most shells, a greater narrowing toward the apex. The dorsal valve differs from that of D. politus in being more rounded on the cardinal margins. It is also to be noted that no traces of muscle scars or vascular markings have been observed on many interiors and casts of the interior of the valves, wliile in D. politus they are prominent on most casts and often on the interior of the valves. The range of outline of the valves of D. politus might include those of D. pro- lificus, but the convexity of the ventral valve and the smooth interior seem to distinguish the latter species. Great numbers of the separated valves occur in several thin layers of gray limestones near the summit of the cliffs on the south side of Marjum Pass. Formation and locality. — Middle Cambrian: (lOz) About 2,900 feet (884 m.) above the Lower Cambrian and 1,500 feet (457.2 m.) below the Upper Cambrian in the central part of the limestone forming la of the Marjum limestone [Walcott, 1908f, p. 179], in the long cliff about 2 miles (3.2 km.) southeast of Marjum Pass [Walcott, 1908f, Pis. XIII and XV], House Range, Millard County, Utah. Dicellomus sp. undt. Walcott. Dicellomus sp. undt. Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 319. (Mentioned as below as a possible new species.) A single specimen of a ventral valve very much like that of Dicellomus appalacJiia (Wal- cott) occurs with material from the Paradoxides forchhammeri zone at Andrarum. A series of specimens would probably prove that it is the representative of an undescribed species. Formation and locality. — Middle Cambrian: (3101) Paradoxides forchhammeri zone at Andrarum, 20 miles (32.2 km.) northwest of Simrishamn, Province of Christianstad, Sweden. o Some of the specimens are labeled asfrom Redwater Canyon and some as from Red Canyon Creek, the former locality being given by Whitfield [1882, p. 340]. i> The specimens from this locality are somewhat doubtfully referred to this species. (See PI. LII, figs. 4 and 4a.) KUTORGINID^. 579 Superfamily KUTORGINACEA Walcott and Schuchert. Family KUTORGINID^E Walcott and Scliucliert. Genus KTJTORGINA BiUings.a Kutorgina Billings, 1861, Geol. Survey Canada, Paleozoic Fossils, vol. 1, p. 9, footnote. (Characterized and dis- cussed as a possible new genus; see below for copy.) Kutorgina Billings, 1861, Eeport on the Geology of Vermont, vol. 2, p. 948, footnote. (Copied from preceding refer- ence.) Kutorgina BrLLiNGS, 1862, Report on the Economic Geology of Vermont, by Hager, p. 220, footnote. (Copied from preceding reference.) Kutorgina Billings, Davidson, 1868, Geol. Mag., vol. 5, p. 312. (Merely questions genus.) Oholella {Kutorgina) (BUlings), Dall, 1870, Am. Jour. Conchology, 2d ser., vol. 6, pt. 2, pp. 154 and 163. (Described.) Kutorgina Billings, Davidson, 1871, British Fossil Brachiopoda, vol. 3, pt. 7, No. 4, p. 342. (Copy of Davidson, 1868, p. 312.) Kutorgina Billings, Dall, 1877, Bull. U. S. Nat. Mus., No. 8, pp. 40-41. (Discussed.) Kutorgina Billings, Zittel, 1880, Handbuch der Palasontologie, Bd. 1, Abth. 1, p. 664. (Described in German.) Kutorgina Billings, Walcott (in part), 1886, Bull. U. S. Geol. Survey No. 30, pp. 101-102. (Original characteri- (Zation, Billings, 1861b, p. 7, copied, and genus described and discussed. The generic description is based on specimens now referred to Micromitra, Micromitra (Paterina), Micromitra (Iphidella), and Billingsella, as well as upon those representing Kutorgina.) ? Kutorgina BiWin^s, Oehleht, 1887, Manuel de conchyliologie, by Fischer, p. 1262. (Described in French, with figures of "Kutorgina cingulata Linnarsson.") Kutorgina Billings, Beecheh, 1891, Am. Jour. Sci., 3d ser., vol. 41, footnote, pp. 345-346. (Generic relations dis- cussed.) Kutorgina BUlings, Hall and Clarke, 1892, Eleventh Ann. Kept. State Geologist New York for 1891, pp. 247-248. (Described and discussed.) Kutorgina Billings, Hall and Clarke, 1892, Forty-fifth Ann. Kept. New York SUte Museum for 1891, pp. 563-564. (Copy of preceding reference.) Kutorgina Billings, Hall and Clarke (in part), 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, pp. 90-94. (Copies Walcott, 1886b, pp. 101-102, on pp. 91-92, and describes and discusses genus, including species now referred to Micromitra, Micromitra (Iphidella), Micromitra {Paterina), Protorthis, and Billingsella, as well as those referred to Kutorgina.) Kutorgina Billings, Hall and Clarke, 1892, idem, p. 183. (Discusses generic relations; see the seventh reference in the synonymy of Botsfordia pulchra, p. 607.) Kutorgina Billings, Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 306-308. (Original characterization, Billings, 1861b, p. 7, copied and genus described and discussed essentially as below.) Kutorgina BUlings, Grabau and Shuier, 1907, North American Index FossUs, vol. 1, p. 209. (Described.) Kutorgina Billings, Walcott, 1908, Smithsbnian Misc. Coll., vol. 53, No. 4, PI. XI, and pp. 142 and 145. (Classifi- cation of genus.) Billings [1861b, p. 9] proposed the genus Kutorgina in a footnote accompanying the description of the type species K. cingulata. He says: Since the above was written I have examined many casts of the interior of this species, and am inclined to the opinion that it is generically distinct from Oholella chromatica. From the very considerable elevation of the beak the dorsal valve must have an area and probably a foramen. In one specimen there are two large oval impressions faintly impressed, but stUl distinctly visible. There is no trace of the lateral scars, and the form, notwithstanding the characters of the surface, conveys the idea of an Orthisina. Should, upon further examination, my suspicions turn out to be well founded, I shall call the genus Kutorgina, after the celebrated European naturalist, Kutorga. From present information of the genus the following diagnosis is prepared: Shells inequivalve, transverse or elongated. Ventral valve convex, Avith apex marginal or incurved over the pseudo-area; cardinal area rudimentary, without any delthjTium or well-defined pseudodeltidium; the latter usually extends one-half the distance from the apex to the plane of the posterior margin of the valve; interior of ventral valve with well-defined main vas- cular sinuses, with a visceral area between the sinuses. Dorsal valve flat or slightly convex, rising to a small, elevated umbo; apex marginal and usually pointing upward; cardinal area n The synonymy for this genus does not give a complete record of the various genera under which the species now included in Kulorgina were formerly placed; it gives only those references in which the genus is discussed or described. To complete the record the following mere generic references are listed: Lin^ula Bomemann [1891, p. 439J. Kutorgimi Bomemann [1891, p. 440J. Orthis f Tate [1892, p. 185]. Kutorgina Freeh [1897, PI. I A, figs. 6a-b]. Kutorgina von Toll [1899, p. 26]. Kutorgina Matthew [1899a, p. 189; 1899d, p. 98]. Kutorgina Walcott [1901, p. 695]. 580 CAMBEIAN BRACHIOPODA. short, rudimentary, and without well-defined pseudodeltidium. Interior of ventral valve with median septum between the central and posterolateral muscle scars. Observations. — The short cardinal areas of the valves leave a broad open space between them for the passage of the pedicle. The areas are more than reflected posterior margins of the valves, as they have transverse lines of growth and a suggestion of a pseudodeltidium. These features are more rudimentary than in Micromitra. Eutorgina includes the larger cal- careous shells, and Micromitra the somewhat more specialized, smaller, corneous shells. The exterior form of the valves of Kutorgina suggest Nisusia festinata (Billings), with wliich the type species, K. cingulata (Billings), is associated in Vermont and at Bic Harbor. The genus was named in honor of Kutorga. Kutorgina cingulata (Billings). Text figures 3, page 299; 8, page 299; 50A-C, page 581; Plate V, figures 1, la-s. Obolella (Kutorgina) cingulata Billings (in part), 1861, Geol. Survey Canada, Paleozoic FoBsils, vol. 1, pp. 8-9, figs. 8 and 10 (not fig. 9). (Described as a new species. Fig. 9 is that of a specimen now referred to Rustella edsoni.) Obolella (Kutorgina) cingulata Billings (in part), 1861, Report on the Geology of Vermont, vol. 2, p. 948, figs. 347 and 349 (not fig. 348). (Text and figures copied from Billings, 1861b, p. 9, figs. 8 and 10, p. 8. Fig. 348 is that of a specimen now referred to Rustella edsoni.) Obolella (Kutorgina) cingulata Billings (in part), 1862, Report on the Economic Geology of Vermont, by Hager, p. 220, figs. 347 and 349 (not fig. 348). (Text and figures copied from preceding reference. Fig. 348 is that of a speci- men now referred to Rustella edsoni.) Obolella cingulata BiLLmos, 1863, Geol. Survey Canada, Fifteenth Rept. Progress, p. 284, figa. 287a and 287b (not fig. 287c). (No text reference. Figs. 287a and 287b are copied from Billings, 1861b, figs. 8 and 10, p. 8. Fig. 287c represents a specimen now referred to Rustella edsoni.) Kutorgina cingulata (Billings), Walcott (in part), 1886, Bull. U. S. Geol. Survey No. 30, pp. 102-104, PI. IX, figs. 1, la-f (not figs. Ig and Ih). (Original description, Billings, 1861b, p. 9, copied and species described and dis- cussed. The specimens represented by figs. 1, la-f are redrawn in this monograph, PI. V, figs. Ic, lb. Id, la, 1, li, and Ih, respectively. Specimens referred to Rustella edsoni are mentioned on p. 103 and are figured, PI. IX, figs. Ig and 111.) Kutorgina cingulata CBiWmgB), Beecher, 1891, Am. Jour. Sci., 3d ser., vol. 41, footnote, pp. 345-346. (Discusses generic relations.) Kutorgina cingulata (Billings), Walcott, 1891, Tenth Ann. Rept. U. S. Geol. Survey, p. 609, PI. LXIX, figs. 1, la-f (not figs. Ig and Ih). (Mentioned. Figs. 1, la-f are copied from Walcott, 1886b, PI. IX, figs. 1, la-f. Figs. Ig and Ih represent specimens now referred to Rv.stella edsoni.) Kutorgina cingulata (Billings), Hall and Clarke, 1892, Eleventh Ann. Rept. State Geologist New York for 1891, PI. IV, figs. 11-13. (No text reference.) Kutorgina cingulata (Billings), Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, p. 92, figs. 47^9; PI. IV, figs. 10-17. (Mentioned in discussing genus. Figs. 47-49 are copied from Walcott, 1886b, I PL IX, figs, lb, la, and If, respectively. Figs. 13, 14, and 17 are copied from figs. 11-13 of the preceding reference.) Kutorgina cingulata (Billings), Frech, 1897, Additional plates inserted in 1897 in Lethasa geognostica, pt. 1, Lethsea palKozoica, atlas, 1876, PL I a, figs. 6a-b. (No text reference. Figs. 6a-b are. copied from Walcott, 1886b, PL IX, figs, la and 1, respectively.) Kutorgina cingulata (Billings), von Toll, 1899, M6m. Acad. imp. sci. St.-P6tersbourg, 8th ser., vol. 8, No. 10, pp. 26-27, PL I, fig. 28. (Described and discussed in German.) Kutorgina cingulata Billings, Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 308-309. (Described and discussed essentially as below, with the exception of the notes and figures on the shell structure.) Kutorgina cingulata von Toll, Walcott, 1905, idem, p. 309. (Species and locality mentioned.) Kutorgina cingulata (Billings), Grabau and Shimbr, 1907, North American Index Fossils, vol. 1, p. 209, fig. 246. (Described. The three figures of fig. 246 are copied from Walcott, 1886b, PL IX, figs. 1, la, and lb.) General form transversely or longitudinally oval; biconvex, with the ventral much more convex than the dorsal valve. Surface marked by concentric lines and ridges of growth and the edo-es by imbricating lamella of growth. Shell substance calcareous and fibrous. The shell is formed of a tliin, dark, compact outer layer and a thick, laminated, calcareous inner layer. It is possible that the tliin outer layer is chitmous, but it does not appear to be so. The L'Anse au Loup and Bic Harbor shells average about 15 mm. long by 17 mm. in width. At the locahty near Swanton, Vermont, ventral valves occur 24 mm. in length and 30 mm. in width, and one large dorsal valve is 20 nam. in length with a width of 30 mm. KUTORGINID^. 581 Ventral valve in young shells moderately convex, becoming more and more convex with increase in size and age; in young shells the slope from the front margin to the apex is nearly straight, and the apex terminates at the posterior edge of the valve above the more or less ele- T ated pseudo-area ; in old shells the curvature from the front to the apex is nearly a semicircle, and the apex terminates m a pointed beak overhanging the pseudo-area; a mesial sinus, of vary- ing strength, occurs on many shells, and in others it is entirely absent; the area is concave on the outer parts; toward the center it becomes shghtly flattened or convex and thus forms a very rudimentary pseudodeltidium; it extends beneath the apex at an angle of about 45° to the plane of the margins of the valve ; the pseudo-area extends about one-half the distance from the apex to the plane of the valve and arches gently from the lateral extremities to the center. A partly exfohated shell shows four dark lines radiattag forward from the umbo and two near the sides that may have something to do with the muscle scars or vascular sinuses. FiGiTRE 50. — Kutorgina cingulata (Billings),. A, Enlargement of a portion of a transverse section of an old shell which shows its laminations and the peculiar manner of growth (X30). B, C, Vertical sections of an old shell, showing the imhricated manner of growth of the outer thin dark layer {X30). This outer layer is not preserved In the specimen represented by A. The specimens from which these sections were made came from Locality 25a, near Swanton, Vermont (U. S. Nat. Mus. Cat. Nos. 15337f,. 15337g, and 15337h, respectively). I thought so in 1886 [1886b, p. 103] but am not sufficiently confident of it now to state it as a settled conclusion. Fine punctee occur on the inner layer of the shell; also numerous radiating lines about one-half milHmeter apart. Dorsal valve gently convex in young shells; with increase in size the umbo becomes more elevated and the apex points upward or terminates at the union of the pseudo-area and the upward slope of the shell on the umbo; in some shells there is a tendency for the valve to become shghtly concave in the space between the margins and the elevated umbo; the area of the valve is narrow and with little character; on some shells it slopes beneath the apex, and on others it slopes backward forming a low angle with the surface of the valve ; the interior of the dorsal valve shows a median septum with two central scars (h) and the anterolateral scars (j) (PL V, fig. Ih); numerous small vascular canals racUate from the central concave area toward the flattened anterior and lateral half of the valve ; a cast of the interior (PI. V, 582 CMIBRIAN BRACHIOPODA. fig. Id) shows two vascular canals radiating forward from near the apex. Radiating lines occur on the interior of the same character as those of the ventral valve. Observations. — Since writing on tliis species in 1886 I have collected specimens showing the character of the areas of the valves and also obtained further information relative to the interior of the dorsal valve. The rucUmentary areas are less advanced in development than those of Micromitra, and the muscle scars of the dorsal valve are much like those of Obolella and Oholus. The presence of rudimentary teeth in Kutorgina cingulata is very difficult to demonstrate by actual observation, owing to the character of the matrix in which the specimens occur. That articulating processes are present, however, is indicated by the fact that in a relatively small collection thirty of the valves are united, and the fact that the dorsal valve is rarely in any other position than that in which it would be if teeth in the ventral valve held it in its normal position. In only a few of the specimens have the valves slid or turned either way, as they frequently do in the inarticulates. The specimens from Bic Harbor and east of Swanton, Vermont, are better than those from the type locafity at L'Anse au Loup, so I have selected material from these locaUties for iUustration, with the exception of a dorsal and ventral valve. Many of the Vermont shells are larger and more fully developed, but specimens of the same size as those from L'Anse au Loup and Bic Harbor are identical in the characters available for comparison. Formation and locality. — lower Cambrian : (392a) Limestones at L'Anse au Loup, on the north shore of the Straits of Belleisle; and (392 l)o arenaceous limestone at Point Amour, Straits of Belleisle; both in Labrador. (2o) Limestone bowlders in conglomerate, on shore at east entrance to harbor at Bic, Rimouski County, Quebec, Canada. (25a)6 Limestone on the Hall (Donaldson's) farm, 2 miles (3.2 km.) east of Swanton; and (319m) shales of No. 6 of the section at Parker's quarry [Walcott, 1891b, p. 278], near Georgia; both in Franklin County, Vermont. (Iv) Shales of No. 3 of the Silver Peak Group, Barrel Spring section [Walcott, 1908f, p. 189], 3 miles (4.8 km.) north of Valcalda Spring and 4 mUes (6.4 km.) west-northwest of the Drinkwater mine. Silver Peak quadrangle (U. S. Geol. Sm'vey), Esmeralda County, Nevada. (35f) About 300 feet (91 m.) below the Middle Cambrian in the limestone forming 6 of the Mount Whyte forma- tion [Walcott, 1908c, p. 242 (11)] just above the tunnel on the north shoulder of Mount Stephen, about 3 miles (4.8 km.) east of Field, British Columbia, Canada. (347 [von Toll, 1899, p. 27]) Near Tschurskaja Station, on Lena River, Siberia. Kutorgina granulata Matthew. Plate V, figiKes 5, 5a-c. Kutorgina granulata Matthew, 1899, Bull. Nat. Hist. Soc. New Brunswick, vol. 4, pt. 3, No. 18, p. 189, PI. I, figs. 2a-d. (Characterized and discussed as a new species. The specimens represented by figs. 2a, 2b, and 2c are redrawn in this monograph, PI. V, figs. 5 and 5a, 5c, and 5b, respectively.) Kutorgina granulata Matthew, 1899, Trans. Roy. Soc. Canada for 1899, 2dser., vol. 5, sec. 4, No. 4, p. 98, PI. V, figs. 2a-d. (Described and discussed. Figs. 2a-d are copied from figs. 2a-d of the preceding reference.) The description by Matthew [1899e, p. 98] follows: Shell substance calcareous. Hinge-line straight, somewhat shorter than the full width of the shell; lateral margin straight near the hinge; front margin broadly rounded. Ventral valve convex, the umbo considerably elevated, the posterior third of the shell somewhat more tumid than the rest; lateral angles somewhat flattened. The area appears to have a deltidium, about one-fifth as wide as the length of the hinge-line; this line, when viewed from behind, appears to be bent up in the middle. Interior: On the posterior half there are a number of low vascular ridges; two of these inclose a median groove, which extends to within a third of the front of the valve; there are about three other ridges on each side. These ridges are most distinct near the umbo, and about three or four are found in the space of 1 millimeter. The dorsal valve is flatter, and has the umbo depressed to the cardinal line, and the sides of the valve toward the hiage much flattened. Interior: There is a median septum extending about one-third of the length of the valve, and faintly indicated for another third to a point where there is a small pit on the inner surface of the valve; and there are also radiating lines as in the ventral valve, but more numerous. The surface is minutely granulated. On the somewhat tumid posterior third of the valve concentric striaa are faintly visible, but they become distinct on the anterior part, and there are very fine radial lines, giving to the summit a These specimens are in the collections of the Geological Survey of Canada. >> The species also occurs in Locality 319e. KUTOEGINID^. 583 of the intervening ridgelets a beaded appearance; at certain intervals stronger concentric striae of growth show on the surface of the shell; there are about five or six of these on its surface. Length, 4 ram.; width, 6 mm.; depth of the ventral valve, 1.5 mm. This species is smaller than K. cingulata and differs in its ornamentation. Observations. — Tliis little shell occurs in reddish hmestone beneath a shaly band in which I found fragments of Olenellus. Except for size it is much Uke Kutorgina cingulata (BiUings) in its general aspect. It diflfers in the details of surface ornamentation and interior radiating Unes. The form owes its specific name to its granulated surface. Formation and locality. — Lower Cambrian: (314b [Matthew, 1899e, p. 97]) Limestone of the "Etcheminian series," at Smith Sound, Trinity Bay, Newfoundland. Kutorgina peculiaris (Tate). Plate V, figure 2, Orthis (f) peculiaris Tate, 1892, Trans. Roy. Soc. South Australia for 1892, vol. 15, pt. 2, pp. 185-186, PI. II, fig. 5. (Described as a new species; see below for copy. The specimen represented by fig. 5 is redrawn in this mono- graph, PI. V, fig. 2.) The original description by Tate follows: Transversely eubquadrilateral, equilateral; hinge-line in the longest anteroposterior [transverse] diameter, straight. Ventral (?) valve flatly convex, with an abruptly depressed and deeply bUobed ventral margin; the mesial furrow decreases in depth as it ascends to near the umbo; the lateral margins are obliquely arched, nearly straight, forming an angle of about 70° with the hinge-line. Surface marked by depressed unequal folds of growth. The author [1892, p. 185] referred to the valre as ventral (?). Its reference to Kutorgina identifies the valve as the dorsal. I do not know of a closely related form. The form owes its specific name to the fact that it seemed to be an unusual representative of the genus to which it was first assigned. Formation and locality. — Middle? Cambrian: (315a) Limestone at Parara, near Ardrossan; and (315) lime- stone at Curramidka; both [Tate, 1892, p. 185] in Yorke Peninsula, South Australia. Kutorgina perugata Walcott. Plate V, figures 3, 3a-e. Kutorgina ■perugata Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, .p. 310. (Described and discussed essentially as below as a new species.) General form ovate, biconvex. Surface marked by concentric lines of growth and more or less strong concentric corrugations. The outer surface is ornamented by a fine network of oblique depressed lines that leave minute rhomboidal elevations between them that look like fine papillse under a moderately strong magnifier, and the cast of the surface has much the same appearance in a transverse light. Shell substance calcareous. A large ventral valve has a length of 14 mm., width 16 mm. A dorsal valve 11 mm. in length has a width of 14 mm. The ventral valve is strongly convex in adult shells, with the highest point near the umbo or at the apex; the apex terminates at or overhangs a rudimentary pseudo-area that slopes beneath the shell at an angle of 45° to 60° to the plane of the margins of the valve; the pseudo- area is concave and about half the length of the space between the apex and the plane of the valve. Casts of the interior show well defined main vascular sinuses, with the outline of the visceral area between them. The dorsal valve is transverse, nearly flat in some examples and slightly convex in others. The surface slopes gradually from the margins to near the umbo, where the slope increases and extends to the upward-pointing apex; a rudimentary pseudo-area slopes backward from the apex. In some examples the pseudo-area appears to be httle more than a bending over 584 CMIBRIAN BEACHIOPODA. of the posterior margins of the shell; in others it has the outline of a slightly convex pseudo- deltidium. Oiservations. — Tliis species in its reticulate surface ornamentation recalls Micromitra {IpMdella) pannula ("\'Vliite) and MicJcivitzia monilifera (Linnarsson). In form the young shells are not unlike Kutorgina cingulata (Billings). A large, imperfect, ventral valve, 24 by 24 mm., of tlais genus, was collected by J. E. Clayton from the Cambrian limestone of the Silver Peak district. It may belong to K. perugata, and it is so referred for the present. From the shales of the Olenellus zone in Silver Canyon, WMte Mountain Range, a series of com- pressed specimens was collected. Some of these show a concave pseudo-area on the ventral valve, also strong main vascular sinuses. Some of the shells from the shales of Locality 175 have lost all traces of surface characters, only a faint, smooth impression remaining. Formation and locality. — Lower Cambrian: (313i) Limestone collected at long. 117° 20' W., lat. 38° N., in the western part of Esmeralda County, Nevada. (Iv) Shales of No. 3 of the Silver Peak group, Barrel Spring section [Walcott, 1908f, p. 189], 3 miles {4-8 hm.) north of Valcalda Spring and 4 miles {6.4 hm.) west-northwest of the Drinkwater mine; (175) <» shales carrying Olenelliis on the divide between Clayton and Fish Lake valleys, about 15 miles (24.2 km.) south-southwest of the town of SUver Peak; and (184) shales at the summit of the Silver Peak Range, 10 miles (16.1 km.) southwest of the town of Silver Peak; all in the Silver Peak quadrangle (U. S. Geol. Survej'), Esmeralda County, Nevada. (7) Shaly beds about 1,000 feet (30.5 m.) above the quartzitic beds, Silver Canyon, WTiite Mountain Range, Inyo County, California. Kutorgina sardiniaensis Walcott. Plate V, figures 4, 4a-c. Kutorgina cingulata Bornemann [not (Billings)], 1891, Nova Acta Acad. Caes. Leop. -Carol. Germanicse Naturse Curio- sorum, Bd. 56, No. 3, p. 440, PL XIX (XXXIV), figs. 22 and 23. (Described and discussed in German; see below for translation. Figs. 22 and 23 are copied in this monograph, PL V, figs. 4b and 4c, respectively.) Lingula rouauUi Bornemann [not Salter], 1891, idem, p. 439, PL XIX (XXXIV), fig. 21. (Characterized and dis- cussed in German. Fig. 21 is copied in this monograph, PL V, fig. 4.) Kutorgina sardiniaensis Walcott, 1901, Proc. U. S. Nat. Mus., vol. 23, p. 695. (Merely changes specific reference of Bornemann's Kutorgina migulata.) Kutorgina sardiniaensis Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 311. (Original description, Bornemann, 1891, p. 440, translated as below and species discussed as below as a new species.) The original description by Bornemann follows: Transversely oval, more or less arched, with a straight margin which is a little shorter than the greatest breadth of the shell. Surface shows strong concentric lines of growth. Found quite commonly in the slates with Olenopsis and Metadoxides near Canal Grande, and rarely in sandstone with Archxocyathus on Punta Pintau. The specimens in the argillaceous shale are always pressed very flat, and are imperfect; in the sandstone, impressions of the outer surface are often found. Here belongs, perhaps, also the shell designated above as Lingula rouaulti (?). All that is known of the species is represented by the illustrations. It appears to be con- generic with Kutorgina cingulata (Billings), but not specifically identical ■wdth it. Formation and locality. — Middle? Cambrian: (354) Yellowish-brown slates not far from the buildings of Canal Grande; (354ta) yellowish sandstone with Archxoeyathus at Punta Pintau and elsewhere; and (354e)6 slate at Porto Canal Grande; all [Bornemann, 1891, pp. 439 and 440] in the island of Sardinia, Italy. Kutorgina sp. undt. Walcott. Kutorgina sp. undt. Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 311. (Characterized and discussed as below as an undetermined species.) Ventral valve transverse, moderately convex; length, 6 mm.; width, 8 mm.; pseudo-area short and sloping beneath the apex at an angle of about 45°. A single cast from a coarse sandstone is all that is known of tliis species. It may be a young shell of K. cingulata (Billings) , but the means of comparison do not justify such a reference. Formation and locality. — lower Cambrian : (47a) Sandstone on the southwest side of Sailings Mountain, 2 miles (3.2 km.) east of Natural Bridge, Rockbridge County, Vu-ginia. a The species is soraewhat doubtfully identified from this locality. & Specimens from this locality are in the collections of the United States National Museum. SCHUCHERTINID^. 585 FamUy SCHUCHERTINID^ Walcott. Genus SCHUCHERTINA Walcott. Schuchertina Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 323. (Mentioned as beiow as a new genus.) Schuchertina Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 4, PI. XI, and pp. 142 and 145. (Classification of genus.) The description of the type species includes that of the genus, as but one species is known. Tyjie. — Schuchertina cambria Walcott. The generic name is given in recognition of the thorough work that Prof. Charles Schuchert has done on the Brachiopoda. Schuchertina cambria Walcott. Plate LI, figures 6, 6a-m. Schuchertina cambria Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 323-324. (Described and discussed as below as a new species.) Shell subovate, mth valves obtusely acuminate, biconvex. Surface marked by concentric lines and striae of growth and fine radiating striae. The inner and outer surface of the shells have very fine punctffi, but no traces of punctaj penetrating tlxrough the shell have been observed. The largest ventral valve has a length of 22 mm.; Avidth, 23 mm.; dorsal valve, length, 17 mm.; mdth, 18 mm. Shell substance calcareous, rather thick on the umbonal region and thin toward the margins. Ventral valve subacuminate, moderately convex; on some of the larger shells a broad mesial fold and arcliing of the frontal margins are present; apex terminates at the margin above a triangular opening or delthyrium; area small and wdthin the plane of the margins of the valve; it is attached to the bottom of the valve and divided midway by a very slight pedicle groove; the margins of the delthyrium-like opening sustain an angle of about 45° to' the plane of the valve, and the solid area within is at its center nearly on the plane of the valve; the anterior maro-ins of the area extend upward to meet the margins of the shell, thus forming a solid arched area. The interior of the valve is marked by radiating, shallow, narrow furrows that var}^ in number and strength in different shells; just in front of the area on each side of the median line oval depressions occur, which correspond in position and shape to the diductor muscle scars of the ventral valve of the Billingsellidse, and they are so interpreted on the figures; traces of the adduc- tor scars are found on each side of the median line. Dorsal valve obtusely acuminate, about as convex as the ventral valve; apex marginal on the broad, low, median arch of the posterior margin; the only trace of an area that has been observed is shown on figure 6j; a broad shallow mesial sinus and projecting front margin occur on adult shells; the position of the anterior and posterior adductor muscle scars is indicated, also the umbonal tliickenin<^ in which the diductor muscles were probably attached, as there is no trace of a cardinal process; radiating furrows Hke those in the ventral valve are strongly marked in adult shells. Observations. — Schuchertina cambria is a shell that, as far as I know, is unique. In its exterior form it suggests a biconvex orthoid genus, and tliis hkeness is further increased by the flabelliform scars of the ventral valve; the smooth surface and soHd cardinal areas suggest Elkania. It may be that Schuchertina is a type derived from some early Cambrian form allied to the BillingseUidse. Its general aspects appear to affihate it with the Orthidse. Formation and locality.— Middle Cambrian: (5k) Limestone in Meagher County on the road to Wolsey, about 1 mile (1.6 km.) south of the divide at the head of Sawmill Creek, and 8 miles (12.8 km.) south of Neihart, Little Belt Mountains quadrangle (U. S. Geol. Survey), Cascade County, Montana. 586 CAMBKIAN BRACHIOPODA. Order NEOTEEMATA Beecher. [viec, young; and zpjifiat perforation.] Superfamily SIPHONOTRETACEA Walcott and Schuchert. Family OBOLELLID^E Walcott and Scliucliert. Genus OBOLELLA Billings, o [Obolus.] Obolella Billings, 1861, Geol. Survey Canada, Paleozoic Fossils, vol. 1, p. 7. (Described and discussed as a new genus.) Obolella Billings, 1861, Report on the Geology of Vermont, vol. 2, p. 946. (Copy of preceding reference.) Obolella Billings, 1862, Report on the Economic Geology of Vermont, by Hager, p. 218. (Copy of preceding refer- ence.) Obolella Billings, 1862, Am. Jour. Sci., 2d ser., vol. 33, pp. 420-421. (Note on date of first publication.) Obolella Billings, Hall, 1863, Sixteenth Ann. Rapt. New York State Cab. Nat. Hist., p. 131. (Original description, Billings, 1861b, p. 7, copied.) Obolella Billings, Meek and Hayden, 1865, Smithsonian Contrib. Knowl., No. 172, Paleontology Upper Missouri, pt. 1, pp. 5-A. (Original description, Billings, 1861b, p. 7, copied.) Obolella Billings, Davidson, 1866, British Fossil Brachiopoda, vol. 3, pt. 7, No. 1, p. 60. (Original description, Billings, 1861b, p. 7, copied and genus discussed.) Obolella Billings, Hall, 1867, Trans. Albany Inst., vol. 5, p. 108. (Original description, Billings, 1861b, p. 7, copied.) Obolella Billings, Davidson, 1868, Geol. Mag., vol. 5, pp. 808-309. (Original description, Billings, 1861b, p. 7, copied and genus discussed.) Obolella Billings, Dall, 1870, Am. Jour. Conchology, 2d ser., vol. 6, pt. 2, pp. 154 and 163. (Described.) Obolella Billings, Davidson, 1871, British Fossil Brachiopoda, vol. 3, pt. 7, No. 4, pp. 338-339. (Copied from David- son, 1868, pp. 308-309.) Obolella Billings, 1872, Canadian Naturalist, 2d ser., vol. 6, No. 2, pp. 217-218. (Described and discussed.) Obolella Billings, 1872, Am. Jour. Sci., 3d ser., vol. 3, pp. 355-357. (Described and discussed.) Obolella Billings, 1876, idem, vol. 11, pp. 176-178. (General description and discussion of genus and species referred to it.) Obolella Billings, Zittel, 1880, Handbuch der Palseontologie, Bd. I, Abth. 1, p. 664. (Described in German.) Obolella Billings, Ford, 1881, Am. Jour. Sci., 3d ser., vol. 21, pp. 131-134. (General discussion of genus and species referred to it.) Obolella Billings?, Walcott, 1884, Mon. U. S. Geol. Survey, vol. 8, pp. 67-68. (Genus discussed in description of "Obolella ambigua.") Obolella Billings, Walcott, 1886, Bull. U. S. Geol. Survey No. 30, pp. 109-112. (Original description, Billings, 1861b, p. 7, and later description, Billings, 1876, p. 176, copied and species referred to the genus discussed.) Obolella Billings, Oehlert, 1887, Manuel de conchyliologie, by Fischer, p. 1262. (Described in French, with figures of "0. desquamata Hall.") Obolella Billings, Hall and Clarke (in part), 1892, Eleventh Ann. Rept. State Geologist New York for 1891, pp. 240- 241. (Described and discussed, the genus Dicellomus being included as a synonjrm.) Obolella Billings, Hall and Clarke, 1892, Forty-fifth Ann. Rept. New York State Museum for 1891, pp. 556-557. (Copy of preceding reference.) Obolella Billings, Hall and Clarke (in part), 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, pp. 66-73. (Genus described, with a general discussion of the genus and the species referred to it. The genus Dicellomus is included as a sjoionym, and the reference also includes species now referred to Bicia, Obolus, etc.) Obolella Billmgs, Hall and Clarke, 1892, idem, pp. 164-165. (Generic relations discussed.) Obolella Billings, Matthew, 1892, Trans. Roy. Soc. Canada for 1891, vol. 9, sec. 4, No. 5, pp. 39-40. (Original description, Billings, 1861b, p. 7, copied and literature on the genus discussed.) a Many of the references to Obolella in the synonymy are based upon or include species now referred to other genera. The present reference of all species formerly placed under Obolella will be found on pages 69-72. The synonymy for this genus does not give a complete record of the various genera under which the species now included in Obolella were formerly placed; it gives only those references in which the genus is discussed or described. To complete the record the following mere generic references are listed: Orbicula f Hall [1847, p. 290]. jlmcu!a? Hall [1847, p. 292]. Obolella f (Orbicula?) Ford [1871, p. 33]. Dicellomus Hall [1873, p. 246]. Obolella Ford [1878, p. 128]. Obolella Walcott [1885a, pp. 115-117; 1885b, p. 21]. Obolella Ford [1886a, p. 466]. Obolella Shaler and Foerste [1888, p. 27]. Obolella Walcott [1890b, p. 36]. Camerella Walcott [lS90b, p. 36]. Obolella Walcott [1891a, p. 611]. Camarella Walcott [1891a, p. 614]. Camarella Hall and Clarke [1894, p. 221]. Protorhyncha ? Schuchert [1897, p. 334]. Obolella Matthew [1899d, p. 70]. Obolella Walcott [1899, p. 448]. Obolella Burr [1900, p. 47]. Obolella Grabau [1900, p. 620]. Obolella Walcott [1901, p. 674]. Obolella ? Matley [1902, pp. 13^ and 139]. Obolella Delgado [1904, p. 364]. Obolella Etheridge [1906, pp. 248 and 249]. Obolella Gorham [1905, PI. I]. Obolella Walcott [1905a, pp. 297 and 313]. Obolella Clark and Mathews [1906, p. 252]. OBOLELLID^. 587 Oholella Billings, MicKwrrz, 1896, M6m. Acad. imp. sci. St.-P6tersbourg, 8th ser., vol. 4, No. 2, pp. 116, 121, and 123-126. (Copies the description of the genus as given by Hall and Clarke, 1892c, pp. 66-67, on pp. 123 and 124 and gives a general discussion of the generic relations of Oholella and Obolus, etc.) Oholella Billings, Grabau and Shimer, 1907, North American Index Fossils, vol. 1, p. 188. (Described.) Oholella Billings, Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 4, PI. XI, and pp. 142 and 145. (Classifica- tion of genus.) Generic characters. — Shell siibequivalve, moderately convex; dorsal valve more elevated at the umbo than the ventral; longitudmally ovate or oval in outlme, with the dorsal valve some- times transversely oval. Surface marked by concentric striae of growth and radiating strise except in the subgenus Glyptias, which has irregular transverse lines crossing the concentric strise. Shell substance unknown in an unaltered condition; it is now calcareous but it may have been calcareocorneous as in Oholus. Shell structure formed of a thin outer layer with many thin inner layers or lamella more or less oblique to the outer layer; the short lamellis of the anterior portion of the valves are more oblique than the longer lamellos of the central and posterior portions and lie at the edges in the same plane as the margins of the valves. Area of the ventral valve rises from the plane of the margins of the valve at angles vary- ing from 10° to 70°; broadly subtriangular when the beak is projecting, other^\'ise rounded at the posterior margin almost as much as the area of the dorsal valve; the latter is usually on the plane of the margins of the valve and broadly rounded posteriorly ; both areas are striated parallel to the base; in the ventral valve a narrow, shallow furrow divides the area midway; the area of the dorsal valve is divided by a narrow, raised, triangular space, bordered on either side by a more or less deeply impressed groove formed by a narrow fold of the area lamellae; outside of this groove, and between it and the outer flexure fold of the area (f), a depressed triangular space occurs that has led authors to consider it as the scar of the point of attachment of cardinal muscles (PL LIV, figs. Ih, li). It sometimes occurs that the inner angle of the area of the ventral valve adjoining the pedicle opening projects forward so as to form a toothlike knob that in the cast is shown by a deep indentation beside the cast of the pedicle opening and between the latter and the projecting cast of the undercut beneath the area (PI. LV, figs. If, Ig). Pedicle opening or foramen of the ventral valve cylindroconical, broad at the base and tapering to a minute apex; position of the external opening a little in advance of the point of the beak; as indicated by casts of the tube in 0. atlantica and a speci- men of 0. crassa. The opening varies in proportional size in different species; it is usually marked by rather strong striae of growth. It extends upward and backward through the shell, very much as does the foramen in Trematobolus and Botsfordia. Splanchnoccele "• of the ventral valve confined to the posterior half of the valve while in the dorsal valve it extends forward to and in some instances beyond the center; in both valves it extends back to the central part of the area which is bounded by the flexure lines (PI. LIV, figs, li, 2g, 2m). Traces of a median septum are shown in the dorsal valve (PI. LIV, figs. Ih, li, and PI. LV, fig. li), but no definite septum has been observed in the ventral valve. A central median ridge of varying degrees of size and length often extends toward the central portion of the dorsal valve; when it is large, a deep rounded groove usually occurs on each side of it on the inner slope of which the central muscle scars may be situated (PI. LIV, figs. 2k-m). Often the median ridge is practically absent (PI. LV, figs, li, 4a). The grooves of the main vascular sinuses begin in each valve at the front margin of the area near the median line, and in the ventral valve gradually extend forward and outward toward the front half of the shell where they begin gently to curve inward, terminating toward the front of the valve, the distance and curvature varying ih different species (PI. LIV, figs. If, 2g, 2h, and PL LV, figs. If, Ih, 3c); in the dorsal valve the main vascular sinuses curve out more rapidly (PL LIV, figs, li, 2m) and are much less prominent; none of the secondary radial canals or the peripheral vascular sinuses have been observed. The course of the parietal scar between the main vascular sinuses is in front of the splanchnoccele in the ventral a Using nomenclature of Mickwitz, 1896. 588 CAJ\IBRIAN BRACHIOPODA. valves (PI. TAV, figs, le, 2g, 2h), also in the same valves it passes closely around the muscle scars situated between the main sinuses and reaches the base of the area in line with the flexure liue of the area; in the dorsal valve it closely follows the outside limits of the muscle scars, but it has not been traced across the main vascular sinuses. The size and position of the pedicle and umbonal muscle scars is imknown, but they are probably similar to those of Oholus. The central scars (h) (PL LIV, figs. Ih, 2k, 2 1) are placed a little distance each side of the median line in the dorsal valve; in the ventral valve they are not separable from the middle and outside laterals, which occur on each side of the front of the visceral area at (c) (PI. LIV, fig. 2h). The middle and outside laterals of the dorsal valve (1) are blended and lie obliquely outward before the transmedian scars (i). The transmedian scars are close to the base of the area in both valves, and lie in the line of the prolongation of the flexure line of the area. In number and relative position the muscle scars of Obolella as far as known are essentially the same as in Oholus. Ohservations. — The genus OioIeUa has been under discussion by authors for over fifty years. In the original description Billings [1861b, p. 7] noted its resemblance to Oholus but claimed that it was distmct on account of the difference in "the arrangement of the muscular impressions." Later [1872c, p. 356] he compared it again with Oholus, but having poor illus- trations of both Oholus and Oholella he failed to discover the true position and relations of the muscle scars in either. It was not until after Mickwitz's memoir [1896] on Oholus appeared, and the collections of Oholella made under my direction during the summer of 1899 were studied, that any correct comparisons could be made. It then became evident that as far as known there was practically no difference in the arrangement of the muscle scars of the two genera, but that there were most essential differences in the cardinal area of the ventral valve. Before working out the fact that the ventral valve was perforated by a pedicle tube or foramen, I was at a loss to find generic difference of value, although I believed that the area of the dorsal valve of Oholella indicated differences not readily explained. The pedicle passage of Oholus varies greatly in size and form, but it is always an open furrow. In Oholella, it is in the ventral valve a cylmdroconical tube, the cardinal area rising from the plane of the margin of the valve beneath the pedicle tube; in the dorsal valve a slightly raised area occupies the place of the broad furrow in Oholus. Oholella is confined to the Olenellus or Lower Cambrian fauna. Oholus, as now limited, appears in the Lower Cambrian, and has its greatest development in the Middle and Upper Cambrian fauna. Bicia gemma is associated with Oholella crassa both at Bic and Troy, and the species was referred to Oholella by BUlings [1872a, p. 218]. It differs so radically from Oholella in the character of the areas of the valves and the interior markings that it is scarcely necessary to institute comparisons between them. Lingulella sckucherti is found associated with Oholella crassa at Troy, New York. The interior markings of Oholella and Botsfordia are quite similar (Pis. LiV and LV, and Pis. LVII and LIX). The same is true of Trematoholus (PI. LXXXIII), but the pedicle open- mg of Botsfordia is above the beak with almost no area beneath, while that of Oholella is above a well-defined false area, and that of Trematoholus is more in advance of the beak. Obolella asiatica Walcott. Plate LV, figures 6, 6a. Oholella asiatica Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 297. (Described and discussed as below as a new species.) General form broad, ovai, with the ventral valve showing a tendency to become bluntly acuminate. Valves gently convex. Surface of shell marked by concentric, raised Imes of growth that form the front edge of narrow lamellas of varying width; the raised lines are highest in front, which gives an imbricated appearance to the surface; fine concentric striae occur on the interspaces between the raised lines. Shell strong, apparently calcareous. OBOLELLID^. 589 The specimens occur in a compact, bluish-gray oolitic limestone. None of them show the area or interior of the valves. The reference to Ololella is based on the general form and calca- reous shell. The shells vary in size from 3 to 5 mm. Oholella asiatica may be compared with young shells of 0. crassa. Its broadly elliptical form and slight convexity distinguish it from other species of the genus. It may be that if material is found showing the interior valves the generic reference will be changed; but with the data now available, the reference is to Oholella. The geological horizon is in some doubt, as the specimens were found m a block of river drift limestone. The associated fragments of trilobites are too indefinite for determination. Oholella is a Lower Cambrian genus as far as knowTi, and other blocks of river drift limestone at the same locality contained fragments of RedlicJiia, so the reference of the species is made to the Lower Cambrian. By error 0. asiatica was included in the list of the Middle Cambrian fossils of Chma [Walcott, 1905b, p. 5]. Formation and locality. — lower Cambrian: (C32') Limestone bowlder collected in river drift 1 mile {1.6 km.) south of Chonpinghien, on Nmihiang River, southern Shensi; and (C17) ferruginous limestone nodules in the brown sandy shales at the top of the Manto shale [Blackwelder, 1907a, p. 27 (list of fossils at top of page) and fig. 6 (bed 15), p. 25], at Changhia, Shantung; both in China. Obolella atlantica Walcott. Text figure 51, page 590; Plate LV, figures 1, la-i. Obolella crassa Shaler and Foerste [not (Hall)], 1888, Bull. Mus. Comp. Zool. Harvard Coll., whole ser. 16, No. 2 (geol. ser. 2), p. 27, PI. I, figs. la-f. (Described.) Obolella sp. Shaler and Foerste, 1888, idem, pp. 27-28, PI. I, figs. 2a-c. (Described.) Obolella atlantica Walcott, 1890, Proc. U. S. Nat. Mus. for 1889, vol. 12, p. 36. (Characterized.) Obolella atlantica Walcott, 1891, Tenth Ann. Kept. U. S. Geol. Survey, p. 611, PI. LXXI, figs. 1, la-c. (Copies Wal- cott, 1890, p. 36. Figs. 1 and lb are copied in this monograph, PL LV, figs, lb and Ic, respectively. Figs, la and Ic were slightly altered before they were used in this monograph, PI. LV, figs, li and Ih, respectively.) Obolella atlantica Walcott, Matthew, 1899, Trans. Roy. Soc. Canada for 1899, 2d ser., vol. 5, sec. 4, No. 3, p. 70. (Copies Walcott, 1890, p. 36, and discusses species.) Obolella atlantica Walcott, Burr, 1900, American Geologist, vol. 25, p. 47. (Discussed.) Obolella atlantica Walcott, Grabau, 1900, Occas. Papers, Boston Soc. Nat. Hist., No. 4, vol. 1, pt. 3, pp. 620-621, PI. XXXIV, figs. 3a-b. (Described.) Obolella crassa Shaler and Foerste, Gorham [not (Hall)], 1905, Bull. Roger Williams Park Museum, No. 9, PI. I, figs. la-f. (No text reference. Figs, la-f are copied from Shaler and Foerste, 1888, PI. I, figs, la-f.) Obolella atlantica Walcott, Gorham, 1905, idem, PI. I, figs. 2a-c. (No text reference. Figs. 2a-c are copied from Shaler and Foerste, 1888, PL I, figs. 2a-c, respectively.) Obolella atlantica Walcott, Grabau and Shimer, 1907, North American Index Fossils, vol. 1, p. 188, figs. 222a-d. (Described. Figs. 222a-d are copied from Walcott, 1891a, PL LXXI, figs. 1, la-c, respectively.) General form ovate, with ventral valve obtusely acuminate in the uncompressed speci- mens; dorsal valve nearly cu-cular, with the transverse diameter the greatest in the best pre- served shells (PI. LV, figs. Ill and li). Valves moderately convex. Surface of the shell marked by concentric striffi and more or less imbricating lines of growth; fine radiating striie that are sometimes raised lines strongly mark most shells, although in some mstances the strife are absent, probably from having been worn awa}^ by abrasion. Wlien the imbricating lamellfe of the shell are broken the surface has the appearance shown by figure Ic. The shells from the limestones of Manuels Brook appear to be relatively thick and formed of several layers, the lamella? being arranged so as to terminate slightly oblique to the outer surface, thus forming the foundation for the imbricating lines of growth. The Smith Point material shows onh^ casts of the outer and umer surfaces, as do most of the specimens from North Attleboro. The thickenmg of the outer portions of the shell by the growth of the oblique lamellte forms a strong interior margin which is usually flat (PI. LV, figs, la and Ih), but it is sometimes oblique to the plane of the edges of the valves (fig. la). The ventral valves average about 5 mm. in length, the largest is 8 mm. ; the dorsal valve is a little shorter than the ventral. 590 CAjMBRIAN brachiopoda. The area of the ventral valve is low and rises from the edge of the valve to meet the beak at an angle of 30° to 45°; it extends well out on the cardinal slopes before merging into them; a narrow furrow divides it midway. The anterior margin of the area adjoining the false pedicle furrow forms a tooth or knob- like projection (PI. LV, fig. le) that forms a deep recess next to the cast of the pedicle tube in the casts of the interior of the ventral valve (fig. If). The surface of the area is marked by fine transverse strife. On each side of the pedicle tube there is a strong undercut which in the cast is replaced by a toothlike projection. The area of the dorsal valve extends nearly as far out on the cardinal slopes as that of the ventral; it is marked midway m the cast by two ridges that converge toward the median line at the posterior margin; these ridges represent furrows such as occur on the areas of some species of Oholus and Lingulella at the side of the flexure lines {Lingulella acutangula (Roemer), PI. XVII, fig. Ih). They are also present in the dorsal valve of Obolella chromatica Billings. The pedicle tube or foramen is beautifully shown in numerous casts of the ventral valve. Wlien the shells are compressed the cast of the tube rests so nearly on the area that one is led to doubt the existence of shell between the area and the tube. (See PI. LV, figs. If, Ig, 3c.) In uncompressed specimens the cast of the tube extends upward and backward as shown by figure Ih. The cast shows a minute apex and trumpet-shaped base. None of the speci- mens show the exterior foraminal opening, nor has it been seen in any species of the genus. The strong pedicle furrow shown on the cardinal area in Plate LV, figure le, does not exist on the specimen, except as indicated by two faint lines. The true pedicle tube opening is shown beneath the area, as represented in figure 5L This was drawn from the same specimen as that represented in Plate LV, figure le. Figure 51.— Oholellaatlantica \fa\cott. / , , n i • ii j. • i m View of ventral valve, tipped back 1 he musclc scars are not weii preserved m the material avail- to show pedicle opening beneath ^|j2e for study. The position of the transmedian scars (i) is indi- thearea(X4). (The same specimen i i i • j_i j. i i j.i ■ i isshowninadiflerentpositioninPi. cated on cach valve; also in the Ventral valve the space occupied Lv,flg. le.) The specimen is from |j„ ^j-^g central, middle lateral, and outside lateral muscle scars. Locality 5o,LowerCambrianshales ^^ ,, i i . ,i • • jt _L^ j_ t at Smith Sound, Trinity Bay, New- Of the vascular markings the mam sinuses ot the ventral foundiand (U. s. Nat. Mus. Cat. yalve are fairly well shown, also the outlines of the parietal scar (PI. LV, fig. Ig). The presence of a short median ridge is indicated on a cast of the dorsal valve (fig. li). Observations. — This small but very interesting species is most nearly related to 0. chro- matica Billings. It is nearly the same size, has the same type of shell structure, and probably the same surface characters. It differs in being less convex, in having a more transverse dorsal valve, less elongate ventral valve, and the narrower marginal border on the inside of the shell, as shown by comparing Plate LV, figure Ih, -with Plate LIV, figure Ih. The separated valves occur in immense numbers in the shales above the limestone on Smith Point and they are also abundant in a ferruginous limestone at Manuels. The mode of occurrence of the species is very much like that of 0. chromatica, of which it appears to be the Atlantic coast province representative; hence the specific name. Formation and locality. — Lower Cambrian : (5o) Just below the Middle Cambrian in shales on Smith Point; and (5n) shales about 275 feet (84 m.) below the horizon of Locality 5o on Smith Point; both in Smith Sound, Trinity Bay, Newfoundland. (5t) Shale and limestone nodules about 20 feet (6 m.) above the base of the Cambrian, on Redrock Point near Chappie Cove, Hollywood Point; (41) sandstone [see Walcott, 18911, p. 260, for position in section] on Manuels Brook; (41a) limestone [Walcott, 1891b, p. 260] on the mainland beneath Topsail Head; and (5p) limestone 300 feet (91.4 m.) southeast of the railway station, Manuels; all on Conception Bay, Newfoundland. (9n and 326e) Dark-purplish siliceous shales on Pearl Street, North Weymouth, Norfolk County; (326f [Burr, 1900, p. 47]) 0.5 mile (0.8 km.) south of North Weymouth, Norfolk County; and (326d) station 2 of Grabau [1900, p. 610], near North Attleboro, Bristol County; all in Massachusetts. Specimens compared with this species occur at the following locality: Lower Cambrian: (59m) Weisner quartzite in the Roan iron mine, Bartow County, Georgia. OBOLELLID^. 591 Obolella chromatica Billings. Plate LIV, figures 1, la-i. Obolella chromatica Billings, 1861, Geo!. Survey Canada, Paleozoic Fossils, vol. 1, pp. 7-8, figs. 7a-d. (Described and discussed as a new species.) Obolella chrovmtica Billings, 1861, Report on the Geology of Vermont, vol. 2, p. 947, figs. 346a-d. (Text and figures copied from preceding reference.) Obolella chromatica Billings, 1862, Report on the Economic Geology of Vermont, by Hager, p. 219, figs. 346a-d. (Text and figures copied from preceding reference.) Obolella chromatica Billings, 1863, Geol. Survey Canada, Fifteenth Rept. Progress, p. 284, figs. 288a-d. (No text reference. Figs. 288a-d are copied from Billings, 1861b, p. 7, figs. 7a-d, respectively.) Obolella chromatica Billings, Hall, 1863, Sixteenth Ann. Rept. New York State Cab. Nat. Hist., p. 132, text figure. (Mentioned. The text figure is copied from Billings, 1861b, p. 7, fig. 7c.) Obolella chromatica Billings, Hall, 1867, Trans. Albany Inst., vol. 5, p. 110. (Text and figure copied from Hall, 1863,- p. 132.) Obolella chromatica Billings, 1876, Am. Jour. Sci., 3d ser., vol. 11, pp. 176-178, figs. 1, 2, 3, p. 176; and figs. 4a-d, p. 177. (Described and discussed. Figs. 4a-d are copied from Billings, 1861b, p. 7, figs. 7a-d, respectively.) Obolella chromatica Billings, Ford, 1881, Am. Jour. Sci., 3d ser., vol. 21, p. 133, figs. 3 and 4. (Compared with 0. crassa. Figs. 3 and 4 are drawn from the figures given by Billings, 1876, figs. 1 and 3, p. 176.) OboUlla chromatica Billings, Walcott, 1886, Bull. U. S. Geol. Survey No. 30, figs. 9 and 10, p. 110 and p. 112, PL XI, figs. 1, la-b. (Copies Billings, 1861b, p. 7, and 1876, pp. 176-177. Figs. 9 and 10 are copied from Billings, 1876, figs. 1 and 3, p. 176. The specimen represented by fig. lb is redrawn in this monograph, PI. LIV, fig. Ih.) Obolella circe Billings, Walcott (in part), 1886, idem, p. 118, PL X, fig. 3 (not fig. 3a). (Original description, Billings, 1872a, pp. 219-220, of Obolella circe copied. The specimen represented by fig. 3 is redrawn in this monograph, PL LIV, fig. li. Fig. 3a represents a specimen of Quebecia dree.) OboUlla chromatica Billings, Walcott, 1891, Tenth Ann. Rept. U. S. Geol. Survey, p. 611, PL LXXI, figs. 2, 2a-b. (Mentioned. Figs. 2, 2a-b are copied from Walcott, 1886b, PL XI, figs. 1, la-b, respectively.) Obolella circe Billings, Walcott, 1891, idem, p. 611, PL LXXI, fig. 3 (not fig. 3a). (Mentioned. Fig. 3 is copied from Walcott, 1886b, PL X, fig. 3. Fig. 3a represents a specimen of Quebecia circe.) Obolella chromatica Billings, Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, p. 67, figs. 28 and 29. (Mentioned in the text. Figs. 28 and 29 are copied from Billings, 1876, figs. 1 and 3, respectively, p. 176.) Obolella chromatica Billings, Walcott, 1899, Men. U. S. Geol. Survey, vol. 32, pt. 2, p. 446, (Note on generic rela- tions.) Obolella chromatica Billings, Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 313. (Copied from Walcott, 1899, p. 446.) General form ovate, with ventral valve obtusely acuminate; dorsal valve broadly rounded, with a tendency to become subacuminate in most specimens. Valves rather strongly convex, with the beak of the ventral valve raised above the plane of the posterior margin, but usually below the greatest elevation of the valve. The beak is slightly incurved over the area of the ventral valve, and that of the dorsal valve terminates at the posterior margin, or may be very slightly curved over it. Surface of the shell marked by concentric striae and lines of growth and fine radiating striae. The latter are usually absent either from the exfoliation of the outer layer of the shell, or from having' been abraded before the shell was embedded in sediment. Shell rather tliick and formed of several layers or lamellee within a thin outer layer. The outer layer usually adheres to the matrix, and the inner layers have been so replaced by calcareous matter that the shell appears to be solid. In a few examples the individual layers are preserved, and the oblique lamellae, encircUng the anterior portions of the valves, form imbricating lines where the outer layer has been removed. Billings [lS61c, p. 947] described the shell as brealdng with a granular fracture, and when weathered as havuig a tendency to fibrous exfoliation, which is true for the specimens in wliich the original structure is lost. The area of the ventral valve is usually lower than the greatest elevation of the surface (PL LIV, fig. la), but it may be as high as any portion of it (fig. Ic); it projects backward at an angle varying from 45° to 70°. Billings states 45° to 60° from material he studied. The area is divided midway by a narrow pseudo-pedicle furrow (p, fig. If). The area of the dorsal valve is well defined in the cast (fig. Ig) and much like that of 0. crassa (Hall) (fig. 2k) and 0. atlantica Walcott (PI. LV, fig. 1 1) . The two ridges on the cast that converge toward the posterior margin are broader than in any other species except OJ lindstromi Walcott (PI. LV, fig. 4a). 592 CAMBRIAN BRACHIOPODA. The position of the depressions (a) these ridges filled on the area is shown by figures Ih, li; they are triangular areas on each side of a raised, central, triangular space that corresponds in position to the pedicle furrow in species like Lingulella (Lingulepis) acuminata, (Conrad) (PI. XLII, fig. 2a). In Oholus apoUinis this portion of the area is sometimes slightly elevated, with a depressed furrow on either side (PI. VII, figs. 6, 7). The cast of the cylindroconical pedicle tube or foramen has been observed in a cast of the interior of the ventral valve (fig. le). This is best seen in Obolella atlantica (PI. LV, figs. If, Ig, Ih). The external foraminal opening has not been observed. The muscle scars are unfortunately not well preserved. The general position of the trans- median and anterior laterals is shown in the ventral and dorsal valves (i, j, PI. LV, figs. If, Ig); the centrals (h) and the anterior laterals (j) in the dorsal valve (fig. Ih). The position of the central, middle, and outside lateral muscle scars is indicated in the ventral valve by the outline of the visceral cavity (v) as shown on figures le. If, but no individual scars can be determined. The outside and middle laterals of the dorsal valve are merged with the transmedian in all the specimens showing them at all; this is undoubtedly owing to the poor preservation of the specimens. The main trunks of the vascular sinuses are fairly well shown in both valves; also the outline of the parietal scar between the sinuses. A rather strong median ridge occurs in the posterior half of the dorsal valve on which the small anterior lateral muscle scars are situated (PI. LIV, figs. Ig-i). Observations. — When the validity of the genus Obolella was attacked [Hall, 1867, p. 110] Billings restudied this, the type species, and gave [1876, p. 176] an elaborate description of all the characters he could determine. Through the kindness of the director of the Geological Survey of Canada and of Prof. J. F. Whiteaves, I have had the opportunity of stud3''ing the material in the Canadian Survey collection. Prof. Alpheus Hyatt also sent me specimens he collected at L'Anse au Loup and I found some very good specimens in a small collection in the United States National Museum, that were not accessible when I illustrated the species in 1886 [1886b, PI. XI, figs. 1, la-b] and 1891 [1891a, PI. LXXI, figs. 2, 2a-b]. Among the new characters discovered are: (a) the narrow pseudo-pedicle groove; (b) the cast of the cylindroconical pedicle tube or foramen; (c) the character of the area of the ventral valve; (d) the vascular impressions of the interior of the ventral valve ; these taken in connection with the features shown b}^ 0. atlantica Walcott establishes the genus Obolella as distinct from Obolus and Dicellomus. The species 0. chromatica Billings is about the same size as 0. atlantica, but it differs in outline, convexity, and details of the areas of both valves. I know of no other species with which it is necessary to compare its specific characters. It is in association with Olenellus thompsoni and other fossils characteristic of the upper portion of the Lower Cambrian fauna in the Gulf of St. Lawrence and the Lake Champlain region. The bits of liraestone brought from Labrador, show great numbers of the separated valves, indicating that they occur in large numbers in one or more layers. Von Toll [1899, p. 27, PI. I, fig. 27] illustrates a specimen from 3 miles (4.8 km.) beyond Bestjachskaja station, on Lena River, Siberia, which he compares with Obolella chromatica BiUings. It is too imperfect to determine with any degree of certainty what it may be. Formation and locality. — Lower Cambrian: (392a) Limestones at L'Anse au Loup, on the north shore of the Straits of Belleisle; (392c [Billings, lS72a, p. 218]) at the Straits of Belleisle; and (3921) arenaceous limestone at Point Amour, Straits of Belleisle; all in Labrador. (314:f) Limestone of B7 of the section at Bonne Bay [Walcott, 1891b, p. 255], Newfoundland. (338p) Sandy limestone one-fourth mile (0.4 km.) northwest of schoolhouae No. 7 in Greenwich, Cambridge quadrangle (U. S. Geol. Snrvey), Washington County, New York. Obolella ceassa (Hall). Text figure 14, page 299; Plate LIV, figures 2, 2a-n. OrbicuJaf crassa Hall, 1847, Nat. Hist. New York, Paleontology, vol. 1, p. 290, PI. LXXIX, fig. 8a. (Described. 1 Auiculaf desquamata Hall, 1847, idem, p. 292, PL LXXX, figs. 3a and 3b. (Described.) OBOLELLIDiE. 593 Oholella (Orbieulaf) crassa (Hall), Ford, 1871, Am. Jom. Sci., 3d ser., vol. 2, p. 33. (Merely changes generic refer- ence.) Oholella crassa (Hall), Billings, 1872, Canadian Naturalist, 2d ser., vol. 6, No. 2, p. 218. (New locality mentioned.) Oholella desquamata (Hall), Billings, 1872, idem, p. 218, fig. 6, p. 217. (New locality mentioned.) Oholella crassa (Hall), Billings, 1872, Am. Jour. Sci., 3d ser., vol. 3, p. 356. (Copy of Billings, 1872a, p. 218.) Oholella desquamata (Hall), Billings, 1872, idem, p. 356, fig. 6, p. 355. (Copy of Billings, 1872a, p. 218, and fig. 6, p. 217.) Dicellomus crassa Hall, 1873, Twenty-third Ann. Kept. New York State Cab. Nat. Hist., p. 246, PI. XIII, figs. 6-9. (Generic reference changed.) Oholella crassa (Hall), Ford, 1878, Am. Jour. Sci., 3d ser., vol. 15, p. 128. (Described and discussed.) Oholella crassa (Hall), Ford, 1881, idem, vol. 21, pp. 131-133, figs. 1 and 2. (Described and discussed.) Oholella chromatica (Hall), Walcott, 1885, idem, vol. 29, pp. 115 and 117; figs. 1 and 2, p. 116. (Mentioned in the text. Figs. 1 and 2 are copied from Ford, 1881, figs. 1 and 2, respectively, p. 131. They represent Oholella crassa and are wrongly referred to in the text, pp. 115 and 117, as Oholella chromatica.) Oholella crassa (Hall), Walcott, 1885, idem, vol. 30, p. 21. (Correction of error on pp. 115 and 117 of preceding reference.) Oholella crassa (Hall), Ford, 1886, idem, vol. 31, fig. 2, p. 466. (No text reference. Fig. 2 is drawn from the speci- men figured by Ford, 1881, fig. 1, p. 131.) OhoUlla crassa (Hall), Walcott, 1886, Bull. U. S. Geol. Survey No. 30, p. 114, PI. X, figs. 1, la-f. (Copies Hall, 1847, p. 290; Ford, 1878, p. 128; and Ford, 1881, pp. 131-133; and discusses species. Figs. Id and If are drawn from the specimens figured by Ford, 1881, figs. 2 and 1, respectively, p. 131. The specimen represented by fig. Ic is redrawn in this monograph, PL LIV, fig. 21.) Oholella crassa (Hall), Walcott, 1891, Tenth Ann. Kept. U. S. Geol. Survey, p. 612, PI. LXXI, figs. 4, 4a-f. (New . locality mentioned. Figs. 4, 4a-f are copied from Walcott, 1886b, PI. X, figs. 1, la-f, respectively.) Oholella circe? Walcott [not Billing.^], 1891, idem, fig. 62, p. 611. (No text reference.) Oholella crassa (Hall), Hall and Clarke, 1892, Eleventh Ann. Kept. State Geologist New York for 1891, PL III, figs. 5-7. (No text reference.) Oholella crassa (Hall), Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, p. 70, PL II, figs. 31-36. (Discussed. Fig. 33 is drawn from the specimen figured by Hall, 1847, PI. LXXX, figs. 3a-b. Figs. 32, 36, and 34 are copied from figs. 5-7, respectively, of the preceding reference.) Oholella crassa (Hall)?, Grabau, 1900, Occas. Papers Boston Soc. Nat. Hist., No. 4, vol. 1, pt. 3, pp. 619-620, PL XXXI, fig. 3. (Described.) Oholella crassa (Hall), Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 321. (Discussed.) Oholella crassa (Hall), Grabau and Shimer, 1907, North American Index Fossils, vol. 1, pp. 188-189, figs. 222e-g, p. 188. (Described. Figs. 222e-g are copied from Walcott, 1886b, PL X, figs. 1, le, and Ic, respectivelj'.) General form ovate to suborbicular, with the ventral valve bluntly acuminate in some examples. Considerable variation in outline occurs, as is shown by Plate LIV, figures 2, 2a, 2b of the ventral valve, and 2k, 2 1 of the dorsal valve. Valves moderately convex, with the beak of the ventral valve depressed below the greatest elevation of the surface and slightly curved over the low area; the beak of the dorsal valve terminates at the posterior margin. Surface of the shell marked by rather strong, concentric stride and lines of growth that interrupt the continuity of fine radiating lines; it is rarely that the surface is well preserved; usually the shells are smooth as though they had been abraded. Shell rather thick, and formed of several layers or lamellae that are more or less oblique to a thin outer layer ; the short oblique lamellae encircling the anterior portion of the valves form imbricating lines when the outer surface is removed (PL LIV, fig. 2b). Very few shells show the shell structure; usually the calcareous matter has so far replaced the origmal shell that there is only a solid calcareous, granular, or calcite shell, as shown by the broken section (fig. 2f). The weathered surface often has a fibrous appearance similar to that of the shell of Oholella cJiromatica Billings. The area of the ventral valve is usually short, but it varies considerabh'^ in this respect (PI. LIV, figs. 2g, 2h, 2j). It overhangs the posterior margin at an angle varying from 45° to 70° and extends well out onto the cardinal slopes; fine strife of growth parallel to the margin cross the area and pass into and across the central furrow; a narrow furrow divides the area midway (PL LIV, figs. 2g, 2h, and 2j). The specimen represented by figure 2h has a roimded cardinal area and a very shallow median furrow; a small pedicle opening is outlined beneath the rounded area, but it is not shown in the illustration. A tendency of the mner point of the area next to the furrow to thicken and project forward into the cavity of the shell is found in several specimens, but it is not as pronounced as in Oholella atlantica Walcott. The area 62667°— VOL 51, pt 1—12 38 594 CMIBRIAN BRACHIOPODA. of the dorsal valve is flat and marked midway by a slightly raised triangiolar space with depressed triangular spaces on each side; what appear to be flexure lines cross the area very much as they do in the area of the dorsal valve of Oholus apollinis Eichwald. Pedicle tube or foramen of ventral valve small, cylindroconical. It has been observed in a broken section of the posterior portion of one shell (PI. LIV, fig. 2n). The external foraminal opening is a little in advance of the extreme end of the beak. The muscle scars are more clearly sho\vn in 0. crassa than in any other species of the genus. The transmedians (i) m both valves are near the margin of the area and close to the mam vascular sinuses; the outside and middle laterals (1) of the dorsal valve can not be sep- arated, but their position a little in advance and slightly outside of the transmedian is well indicated on the casts of the interior (PI. LIV, figs. 2k and 21) ; the anterior laterals of the ventral valve are shown by figure 2h at j, a little in advance and outside of the transmedian, also in the dorsal valve as small oval scars each side of the median line near the center of the shell; the central scars (h) of the dorsal valve are elongate, oval, and situated on the inner edge of a groove bounding the visceral cavity, about one-fourth of the distance between the anterior lateral scars and the posterior margin of the shell; the central, middle lateral, and outside lateral scars of the ventral valve have not been differentiated; the area (c) in which they should occur (PL LIV, figs. 2g and 2h) is clearly outlined in a number of specimens; the pedicle and imibonal scars have not been observed. The main vascular sinuses of the ventral valve are strongly marked and extend forward well toward the front margin of the shell; they vary in form and position in dift'erent shells largely on account of the thickness and manner of deposit of the shell substance. The figures - 2g-j fllustrate better than any description I can give the character of the sinuses and the prin- cipal variations as far as known to me. In the dorsal valve the main sinuses extend farther out from the median line than in the ventral, but they are small and inconspicuous when com- pared with the latter or with the strongly impressed grooves on each side of the visceral cavity. The latter grooves rise to give the peculiar ridges having the appearance of frog legs that are so strongly marked in the cast of the dorsal valve of Oholus (Lingulobolus) spissus (Billings) (PL XVI, fig. 2d). Observations. — In a former paper [1886b, pp. 114-116] I have quoted the descriptions of this species by Hall and Ford. With the material now available and our more detailed infor- mation of the genus, it is unnecessary to repeat or to comment on those descriptions or on the slight additions made by myself, except the reference made to Aviculaf desquamata HaU. Bfllings [1861b, p. 7] thought that Avicula? desquamata Hall might be referred to Obolella, and Ford [1871, p. 33] referred Orhicula? crassa Hall to the same genus. Later [1878, p. 128] the latter observer placed Aviculaf desquamata as a synonym of 0. crassa, saying: The species known as Obolella crassa of the Troy beds may also be briefly noticed in this connection. It includes the species already widely known under the name of 0. desquamata from the same locality, this latter, as may be shown, having been founded upon the dorsal valve of the former. The ventral valve is always more acutely pointed at the beak than the dorsal, but beyond this feature there is nothing, so far as I have been able to discover, by which they may be distinguished from each other externally. The surface of each when perfect is both radiately and concen- trically striated. As a rule, however, the imbricating edges of the successive layers of growth are the only markings visible. Obolella crassa is one of the large species of the genus. There is no closely allied species on the American Continent, but 0. mobergi, of Sweden, may be considered as such in the Scan- dinavian Cambrian faunas. Some examples of the outer surface of 0. mobergi resemble 0. crassa, but a careful comparison of the form and also of the interior of the valves shows striking specific differences (Pis. LIV and LV). The presence of a well-marked median furrow on the area of the ventral valve and a relatively smaU pedicle tube are noticeable featm-es in 0. crassa. Obolella crassa is very abundant in some of the limestone layers interbedded in the siliceous shales at Troy, New York. It also occurs in the limestone conglomerate of the same region. It is associated with the EUiptocephala asapJioides fauna in the Hudson Valley, and a similar fauna is found in the limestone bowlders of the Bic conglomerate in the St. Lawrence OBOLELLID^. 595 Valley. I have found no traces of it in the Atlantic province Cambrian formations. Strati- graphically, it is, I believe, the oldest representative of its genus in America. Formation and locality. — Lower Cambrian: (392c [Billings, 1872a, p. 218]) At the Straits of Belleisle, Labrador. (56b) Limestone bowlder in conglomerate, on the south shore of Orleans Island, below Quebec; (2o) limestone bowlders in conglomerate, on shore at east entrance to harbor at Bic, Rimouski County; and (319b) conglomeratic limestones containing Olenellus ?, at St. Simon; all in Quebec, Canada. (319k) Calcareous sandstone near the base of the section west of Parker's quarry, on cliff overlooking Lake Champlain, east of .Georgia, Franklin County, Vermont. (2b) <» Limestone just north of Beman Park, in the northeastern part of the city of Troy, Troy quadrangle (U. S. G«ol. Survey); (27) even-bedded and conglomerate limestones on the ridge ill the eastern suburb of Troy, Troy quadrangle (U. S. Geol. Survey); (338q [Eall, 1847, P- 290]) calcareous beds 2 miles {3.2 km.) northeast of Troy, Troy quadrangle {U. S. Geol. Survey); (27a) reddish sandstone about 1 mile (1.6 km.) east of Lansingburg, north of Troy, Cohoes quadrangle (U. S. Geol. Survey); and (29a) limestone 1 mile (1.6 km.) below the New York Central Railroad depot at Schodack; all in Rensselaer County, New York. (338o) Shale on Moses Hill, 2 miles (3.2 km.) west of North Greenwich; and (35) limestones 1.5 miles (2.4 km.) north of Bald Mountain; both in the Schuylerville quadrangle (U. S. Geol. Survey), Washington County, 6 New York. (326d) "Station 2" of Grabau [1900, p. 610] near North Attleboro, Bristol County; and (326g [Grabau, 1900, p. 620]) limestones at East Point, Nahant, Essex County; both in Massachusetts. Specimens that are somewhat doubtfully referred to tliis species occur at the following localities : Lower Cambrian: (50a) Sandstone 2 miles (3.2 km.) northwest of York, York County; and (12v) sandstone above the quartzite 1 mile (1.6 km.) west of Fruitville on Little Conestoga Creek, Manheim township, Lancaster County; both in Pennsylvania. (59m) Weisner quartzite in the Roan iron mine, Bartow County, Georgia. Obolella ceassa elongata n. var. Plate LV, figures 5, 5a. In the collections from St. Simon there is an oval or elongate ovate form to which it appears to be desirable to give a varietal name. Its surface is marked by stronger concentric lines of growth than usually occur on the less elongate shells of 0. crassa (Hall), and the valves, especialljr the dorsal, are much more elongate than those of 0. crassa. One ventral valve of the latter species from Troy, New York, is nearly as elongate (PL LIV, fig. 2a), but it is broader on the posterior half of the shell than those from St. Simon referred to the variety elongata. Formation and locality. — Lower Cambrian: (319b) Conglomeratic limestones containing Olenellus?, St. Simon, Province of Quebec, Canada. Obolella groomi Matley. Text figure 52, page 596. Obolella{f) groomi Matley, 1902, Quart. Jour. Geol. Soc. London, vol. 58, pt. 1, pp. 137 and 139, figs. 1-2, p. 137. (Described and discussed as a new species, see below for copy. Fig. 1 is copied on p. 596 as fig. 52.) The original description by Matley follows : Shell oval, moderately convex, about as long as wide, widest toward the front, which is moderately to well rounded. Lateral margins straight or slightly convex, converging posteriorly to form a rounded beak. Hinge-area absent, or not well defined. Sides usually somewhat deflected. Surface covered by about thirty small but well-marked, con- centric, rugose ridges. No radial striae. Casts of the interior show nothing but very faint traces of markings. About 4.5 mm. long by 5 mm. wide. Type in Professor Groom's collection. Other specimens measure: Length. Width. mm. mm. 7 5.5 5.5 5 4.5 4.75 a The species also occurs at Locality 2d. b This species also occm's at Locality 20. 596 CAMBRIAN BRACHIOPODA. Several specimens of this shell have been collected by Prof. Theodore Groom, in honor of whom the specific name is given. With no knowledge of its internal characters, the generic reference is necessarily provisional, but the species approaches in outline and external characters some American forms of the genus Obolella, especially the type species of the genus, 0. chromatica Billings, of the Olenellus zone of Canada, from which, however, it appears to be separated by the form of the beak and the shape of the umbonal region. There is little to add to Matley's description and observations, except to call attention to the resemblance in general form and surface of this species to the figure of Obolella crassa elongata on A a' Plate LV, figure 5. As described and illustrated the species appears Figure 52. — Obolrlla groomi Matley. , i , /^t 7 77 A, A', Top and side views of a ven- tO be a true OboleUa. tral valve. The figures are copied „ -r ^ ^ ■ /««. \ .!■•«■ 1 . • 1. from Matley [1902, p. 137, fig. ij. FORMATION AND LOCALITY. — Lower Cambrian: (304c) « 'Malvern quartzite at Raggedstone Hill; and (304d)« "Malvern quartzite" at Midsummer Hill; both [Groom, 1902, p. 94] in the Malvern Hills, between Herefordshire and Worcestershire, England. Obolella ? lindstromi Walcott. Plate LV, figures 4, 4a. Obolella lindstromi Walcott, 1901, Proc. U. S. Nat. Mus., vol. 23, pp. 674-675. (Characterized and discussed essen- tially as below as a new species.) This species differs from Oholella mohergi Walcott in the more subacuminate outline of the valves, the surface characters, and the interior of the dorsal valve. The last is well shown by comparing figures 3e and 4a (PL LV). Figures 3 and 4 clearly indicate the differ- ence in surface of the two species. The surface of 0. f lindstromi is much like that of Bicia gemma (PI. L, figs, la and Id). The ventral valve (PI. LV, fig. 4) occurs in a hard gray sandstone of the Mesonacis torelli zone, and the cast of the dorsal valve (fig. 4a) is from one of the brown sandstone masses that occur witliin the gray sandstone at Sularp. I am not sure that the dorsal valve illustrated actually belongs to tliis species, as it is not associated with the typical ventral valve. It differs from the typical dorsal valves of 0. mohergi in being more acuminate, and there is no corresponding ventral valve associated with it in the material studied. I take pleasure in naming the species in honor of Dr. G. Lindstrom, to whom all paleon- tologists are deeply indebted for liis many fine contributions to the paleontology of the Silurian formations of Scandinavia. Formation and locality. — Lower Cambrian: {321v) Gray sandstone of the Mesonacis torelli zone at Bjorhelunda, south of Simrishamn, Province of Christianstad; and (321s) brown sandstone interbedded in gray sandstone at Sularp, near Lund, Province of Malmohus; both in Sweden. Obolella minor (Walcott). Plate LIV, figures 3, 3a-d. Camerella minor Walcott, 1890, Proc. U. S. Nat. Mus. for 1889, vol. 12, pp. 36-37. (Described and discussed as a new species.) Camarella? minor Walcott, 1891, Tenth Ann. Rept. U. S. Geol. Survey, p. 614, PI. LXXII, figs. 4, 4a-d. (Text copied from preceding reference. Figs. 4, 4a-d are copied in this monograph, PI. LIV, figs. 3b, 3, 3c, 3d, and 3a, respectively.) Camarella minor Walcott, Hall and Clarke, 1894, Nat. Hist. New York, Paleontology, vol. 8, pt. 2, p. 221. (Char- acterized and discussed.) Protorhyncha .? minor (Walcott), Schuchert, 1897, Bull. U. S. Geol. Survey No. 87, p. 334. (Generic reference changed and generic relations discussed.) Oholella minor (Walcott), Clark and Mathews, 1906, Maryland Geol. Survey, vol. 6, 1906, pt. 1, p. 252, PI. XVI, figs. 13 and 14. (No text reference. Figs. 13 and 14 are copied from Walcott, 1891a, PI. LXXII, figs. 4a and 4c, respectively.) General form ovate, biconvex. Surface smooth or marked by concentric lines and varices of growth. Ventral valve subacuminate, moderately convex, with the most elevated portion at the umbo, wliich curves downward toward the small apex; the posterior or umbonal third o Neitlier Groom [1902, p. 94] nor Matley [1902, p. 137] states which of these localities is the type locality. OBOLELLID^. 597 of the valve is usually more or less tumid, a ridge of growth separating it from the anterior portion of the shell; area nearly on the plane of the margins of the valve and divided midway by a narrow, deep, pedicle furrow; casts of the interior show that the area formed a shelf on each side of the pedicle furrow. Dorsal valve transversely ovate; a narrow, short area and a slight median ridge are indicated on a cast of the interior. Tliis shell is small. A large ventral valve measures, length, 7 mm. ; -width, 6 mm. ; a dorsal valve, length, 6 mm.; width, 6.5 mm. Observations. — The characters of tliis little shell, as far as they are laiown, are those of Oholella. In my original description I gave an erroneous interpretation to the cast of the interior of the ventral valve. At that time I did not know much of the interior of Oholella, and also considered the cast of the space beneath the area beside the pedicle groove as indicating the existence of plates as in Pentamerus. In the absence of the shell or fine casts it is impossi- ble to determine conclusively whether a foraminal tube existed, as in Oholella atlantica Walcott, or not; one cast indicates that such was the case. The form and long area distinguish this from other species of the genus. Formation and locality. — Lower Cambrian: (16f) Sandstone at the mouth of Little Antietam Creek, near Eakles Mills; (47d.)o sandstones 1 mile (1.6 km.) east-southeast of Smithsburg; (47e) sandstone on Observatory Hill, 2 miles (3.2 km.) south of Keedysville; and (47f) sandstone at Eakles Mills, 2 miles (3.2 km.) south of Keedysville; all in Washington County, Maryland. (32) Sandstone on the south slope of Stissing Mountain, Dutchess County, New York. (49b) Sandstone 2 miles (3.2 km.) northwest of Emigsville, York County; (49c) sandstone in ridge just north of the railway station in Emigsville, York County; (49d) sandstone 3 miles (4.8 km.) east of Waynesboro, Franklin County; (49e) sandstone 1 mile (1.6 km.) south of Mount Zion Church, and 4 miles (6.4 km.) northeast of York, York County; and (49f)o sandstones of Mount Holly G^p, South Mountain, Cumberland County; all in Pennsylvania. (47a) Sandstone on the southwest side of Sailings Mountain, 2 miles (3.2 km.) east of Natural Bridge, Rockbridge County, Virginia. (47c) Sandstone 2 miles (3.2 km.) west of Harpers Ferry, Jefferson County, West Virginia. Obolella mobeegi Walcott. Plate LV, figures 3, 3a-f . ? Obolusf sp. Kjeritlf, 1873, Om Skuringsmaerker, Glacialformationen, Terrasser, og Strandlinier, etc., 2: Sparagmit- fjeldet, p. 83, figs. 10 and 11. (No text reference.) Obolella mobergiVf ALCOTT, 1901, Proc. IT. S. Nat. Mus., vol. 23, pp. 673-674. (Described and discussed as below as a new species.) General form ovate, with the ventral valve subacuminate and the dorsal valve obtusely sub- acuminate; valves moderately convex; beak of the ventral valve slightly elevated above the plane of the shell; beak of the dorsal valve curved down to the plane of the margin. vSurface of the sheU marked by concentric lines and strije of growth, and in some examples by rather strong, radiating, broken, and slightly irregular raised lines of the same character as those of Bicia gemma (Billings). The shell is formed of a thin outer layer, and numerous inner layers or lameUse over the anterior half of the shell. These imbricating inner lamellae are oblique to the .outer layer, very much as in Oholella (Glyptias) favosa (Linnarsscm) . A ventral valve 10 mm. in length has a width of 9 mm. A dorsal valve 9 mm. long has the same width. The area of the ventral valve is of medium length and tipped back from the edge of the valve to meet the beak; it extends well out onto the cardinal slopes, and is divided midway by a narrow furrow. The surface of the area is marked by rather strong transverse strife crossing the area. On each side of the base of the pedicle tube there is a rather strong undercut which in the cast is replaced by a marked toothlike projection. The area of the dorsal valve is narrow. The cast of the pedicle tube or foramen is large, cylindroconical, and encircled by a number of rather strong lines of growth (PL LV, fig. 3c) . The casts of the interior of the ventral valve show a central visceral area, very much like that in 0. crassa (Hall); also two strongly marked vascular sinuses that extend weU into the a Doubtfully identified from this locality. 598 CAMBRIAN BRACHIOPODA. middle of the valve. No clearlj^ defined muscle scars are shown on any of the specimens. Casts of the interior of the dorsal valve give little satisfactory data in relation to the muscle scars. The cast illustrated by Plate LV, figure 3e, shows a part of the outline of the visceral area, also the impression of the transmedian muscle scar. Ohservations. — This species has been considered as the European representative of 0. crassa (HaU), which occurs at the same relative stratigraphic horizon at Troy, New York. The Swedish form differs specifically from the American in having a slightly more elongate pedicle tube and in having the interior thickenings of the area more strongly developed. It differs from 0. atlantica Walcott and 0. chroniMica Billings in having a much more robust shell and in manj^ sUght details. Kjerulf [1873, p. 83, figs. 10 and 11] illustrates, without text reference, a form that appears to be referable to this species. It is found in Locality 324, at Tomten, Norway, in association with Ilolmia Tcjerulfi, Arionellus, and Oholella {Gh/ptias) favosa. The specific name was given in honor of Dr. J. C. Moberg. Formation and locality. — Lower Cambrian: (331v) Gray sandstone of the Mesonacis torelli zone at Bjorkelunda, south of Simrishamn, Province of Chris- tianstad; and (321s) brown sandstone in- terbedded in gray sandstone at Sularp, near Lund, Province of Malmohus; both in Sweden. (8v) Shales and dark, calcareous, ferruginous rock in the upper portion of the Eolmia Tcjerulfi zone, Ringsaker; and (324 [Kjerulf, 1873, pp. 73 and 83]) green shales with interbedded calcare- ous sandstone at Tomten, in Ringsaker; both in the Province of Hedemarken, Norway. Obolella vermilionensis n.sp. Text figures 53A-E. Figure Si.— Obolella vermilionensis n. sp. A, Cast of the interior of a ventral valve, the type specimen (X 2), from Locality 60b, Lower Cambrian sandstones in Vennilion Pass, Alberta, Canada (U. S. Nat. Mus. Cat. No. SGOOOa). B, B', Top and baclj views of a dorsal valve associated with the specimen represented in figure 53A (X 2) (U. S. Nat. Mus. Cat. No. 56606b). C, Ventral valve preserving its shape but from which all traces of shell sub- stance have been removed (X 2). It is associated "with the specimens represented by figures 53A and 53B (U. S. Nat. Mus. Cat. No. 56606c). D, Ventral valve from Locality 14p, Lower Cambrian sandstones near Resting Springs, California (U. S. Nat. Mus. Cat. No. 51964a). E, Associated dorsal valve, Locality 14p ( U. S. Nat. Mus. Cat. No. 51964b). This species is represented by numerous casts in a fine- grained sandstone. General form Shells fairly convex and uniformly larger than those of the suborbicular, slightly transverse other species of the genus. The beak of the ventral valve is somewhat lower than the greatest elevation of the shell, and does not reach the posterior margin. Both the beak and the area are, as a rule, poorly pre- served, but the incurving of the growth lines to form the area is well shown in several specimens. Interior casts of the ventral valve show traces of vascular sinuses. The beak of the dorsal valve terminates at the posterior margin, but is raised slightly above the plane of the margin of the shell. Shell substance not preserved, but the casts show indications of both radial and concentric striation. Ohservations. — The representatives of this species occur in such widely separated parts of the Rocky Mountain province as California and British Columbia, but the forms are identical and are associated in each district with Ilolmia and Orthotlieca. Oholella crassa approaches this species in the size of some of its specimens, but it is uni- formly smaller and less convex. Oholella vermilionensis also differs from the former species in its transverse outline. Further comparison is impossible because of the lack of knowledge as to the interior of Oholella vennilionevsis. OBOLELLIDZE. 599 Formation and locality.— Lower Cambrian: (60b) About 2,300 feet (702m.) below the Mount Whyte formation and 200 to 300 feet [61 to 92 m. ) above the Lake Louise shale, in ike St. Piran sandstone [Walcott, 1908a, p. 4], at Vermilion Pass, on the Continental Divide between British Columbia and Alberta, west-southwest of Castle, on the Canadian Pacific Railway, Alberta, Canada. (53) Sandstones in the lower portion of 3d of the Waucoba Springs section [Walcott, 1908f, pp. 187 and 188], 1 mile (1.6 km.) east of the Saliae Valley road about 2.5 miles (4 km.) east-northeast of Waucoba Springs; (312a) sandstones of 3b of the Waucoba Springs section [Walcott, 1908f, p. 187], east of the Saline Valley road east of Waucoba Springs; (14p) sandstone near Resting (Freshwater) Springs, which is in the southwest corner of T. 21 N., R. 8 E., on Amar- gosa River; (8b) limestone in ToUgate Canyon, about 15 miles (24.2 km.) east of White Pine, White Mountain Range; and (176) shales and interbedded limestones, between massive limestones carrying Archseocyathus, at the south end of Deep Spring Valley; all in Inyo County, California. Obolella wirrialpensis Etheridge. Plate LV, figures 7, 7a-b. Obolella wirrialpensis Etheridge, 1905, Trans. Roy. Soc. South Australia, vol. 29, p. 248, PI. XXV, figs. 2 and 3. (Described and discussed as a new species. The specimen represented by fig. 2 is redrawn in this monoo-raph PL LV, fig. 7b.) Obolella wirrialpensis calceoloides Etheridge, 1905, idem, p. 249, PL XXV, figs. 4-6. (Characterized and discussed as a new variety. The name placed at the head of the paragraph is "Obolella sp.," the term calceoloides hemg applied to it in the text.) The original description by Etheridge follows: Valve (? pedicle) ovate to subquadrate, gently convex, rising dorsally into a small umbo; rounded ventrally and without emargination; lateral angles rounded. Internal muscle scars hardly at all curved, diverging from one another, extending far forward, and tapering to a fine point. Surface characters very marked and distinctive, consisting of a series of clean-cut, flat, concentric steps, the "tread " of each step practically at right angles to its "riser; " no concen- tric or radial striae of any kind. After a study of the type specimens of this species and several specimens that were worked out of a block of the hmestone received from Mr. Walter Howchin, of the University of Ade- laide, I have concluded that" the variety calceoloides is a narrow form of the species. There are a number of intermediate forms which render it difficult to separate a distinct variety. The species resembles Obolella crassa (Hall) in outline and convexity more than any other species referred to the genus. The specific name is derived from Wirrialpa, the type locality. Formation and locality.— Lower? Cambrian: (315d [Etheridge, 1905, p. 248]) Limestone near Wirrialpa, Flinders Range, South Australia. Obolella ? sp. undt. Obolella cf. atlantica Delgado, 1904, Communicapoes Commissao Servi^o Geol. Portugal, tome 5, fasc. 2, p. 364, PL IV, fig. 35. (Described in French.) This form, Delgado states [1904, p. 364], is represented by a single specimen, which he compares with Obolella atlantica Walcott. The material is too poor to base a specific deter- mination upon. The photograph of the cast of the interior of a small ventral valve 4.5 mm. long and 6 mm. wide indicates that the specimen may be referred to this genus, but it may belong to Trematobolus, Botsfordia, or an allied genus. The Obolella maculata referred to by Delgado [1904, p. 364] has in this monograph been referred to Acrotliele villaboimensis. Formation and locality.— Lower Cambrian: (351 [Delgado, 1904, p. 364]) Shales at Monte de Valbom, to the northeast of Villa Boim, Province of Alemtejo, Portugal. GLYPTIAS Walcott,o subgenus of OBOLELLA. Obolella (Glyptias) Walcott, 1901, Proc. U. S. Nat. Mus., vol. 23, p. 675. (Mentioned as below as a new subgenus.) Obolella (Glyptias) Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 4, PL XI, and pp. 142 and 145. (Classifi- cation of subgenus.) The subgenus Glyptias is based on the peculiar surface sculpture and the very short area. Type. — Lingula (?) favosa Linnarsson. a Prior to the deflnition of this subgenus the type species was described under Lingula ? Linnarsson [1869a, p. 356: 1869b, p. 406]. 600 ■ CM'IBRIAN BRACHIOPODA. Obolella (Gltptias) favosa (Lianarsson) . Plate LV, figures 2, 2a-d. Lingula (f) favosa Linnarsson, 1869, Ofversigt af K. svensk. Vet.-Akad. Forhandl. for I860, vol. 26, No. 3, pp. 356-357. (Described and discussed in Swedish as a new species.) Lingula (f) favosa Linnarsson, 1869, Geol. Mag., vol. 6, p. 406. (Translation, of the preceding reference.) f Diseina? sp. Kjektilf, 1873, Om Skuringsmterker, Glacialtormationen, Terrasser, og Strandlinier, etc., 2:Sparagmit- fjeldet, p. 83, figs. 12 and 13. (No text reference.) Obolella {Glyptias) favosa (Linnarsson), Walcott, 1901, Proc. U. S. Nat. Mus., vol. 23, pp. 675-676. (Described and discussed essentially as below.) General form ovate, with the ventral valve subacuniinate and the dorsal valve obtusely rounded; valves moderately convex. The dorsal valve is abruptly curved downward at the beak to the plane of the edge of the shell, while the beak of the ventral valve is slightly above the margin, the posterior edges of the shell curving up to meet it. Surface of the shell marked by very fine concentric Hues or strise of growth, crossed transversely by undulating, slightly lamellose hnes in almost identically the same manner as in Obolus ( Westonia) stoneanus (Whit- field) of the Upper Cambrian of Wisconsin (PL XXVIII, fig. 2d). When the outer surface of the shell is exfoliated or worn off by attrition, which is the usual condition, the surface of the inner layers shows fine radiating and concentric strise. The shell is formed of a very thin, highly ornamented outer layer and numerous inner layers or lamellaB; the latter over the anterior portions are oblique to the outer layer, and when the shell is partly exfoliated they appear as imbricating layers very much as in Obolus matinalis (HaU) . The largest ventral valve in the collection has a length of 7 mm. and a width of 6 mm. An associated dorsal valve 6 mm. long has a width of 6.25 mm. The area of the ventral valve is narrow and rises slightly to meet the beak, which is ele- vated above the posterior margin. The pedicle tube or foramen is short and small, and, judging from the appearance of the specimens where the beak of the valve is broken away, it opened near the apex of the beak. On the dorsal valve there is no evidence of a true area except in the presence of a narrow, thickened rim somewhat like that of the dorsal valve of Bicia gemma (Billings). None of the muscle scars are shown in the ventral valve. The position of the central and anterior lateral scars of the dorsal valve is indicated near the outline of the vis- ceral cavity (PI. LV, fig. 2c). Of the vascular markings, the main sinuses are clearly shown in each valve, also the outline of the parietal scar. AH that is known of them is well shown on Plate LV. Observations. ^This beautiful little shell has remained without illustration since Linnarsson [1869a, p. 356] gave it a name, based on the "singular sculpture" of the outer shell. In a collection made for me by Mr. Schmalensee, a collector in the Geological Survey of Sweden, there were several specimens showing casts of the interior more or less imperfectly. From these I was able to ascertain that the shell has the generic characters of Obolella, although differing from the typical species of that genus in the character of the surface ornamentation. The outer surface has been seen only on the posterior umbonal portion of the valves in the shells collected. Kjerulf [1873, p. 83, figs. 12 and 13] illustrates, without text reference, a form that appears to be referable to this species. It occurs in LocaHty 324 at Tomten, Norway, in association with Obolella mobergi, Holmia hjerulji, and Arionellus. , Formation and locality.— Lower Cambrian ; (309c) o ' ' Fucoid sandstone " at Billingen, east of Skara; and (309d) "fucoid sandstone" at Lugnds, 8 miles {1^.8 hm.) south-southeast of Mariestad; both [Linnarsson, 1869a, p. 357] in the Province of Skaraborg, Sweden. (324 [Kjerulf, 1873, pp. 73 and 83]) Green shales with interbedded calcareous sandstone at Tomten, in Ringsaker, near Lake Mjosen, Province of Hedemarken, Norway. a Specimens from this locality are included in the collections of the United States Nationnl Museum. OBOLELLID^. 601 Genus BOTSFOBDIA Matthew. « Oholus (Botsfordia) Matthew, 1891, Trans. Roy. Soc. Canada for 1890, 1st ser., vol. 8, sec. 4, No. 6, p. 148. (Merely uses the term "Obolus (Botsfordia) pulcher" in the text.) Obolus (Botsfordia) Matthew, 1892, Trans. Roy. Soc. Canada for 1891, 1st ser., vol. 9, sec. 4, No. 5, p. 63. (Merely proposed as a new subgenus.) Lingulella Hall and Clarke (in part), 1892, Eleventh Ann. Rept. State Geologist New York for 1891, pp. 232-233. (The genus Lingulella is described, Lingulella davisi being given as the type, but Botsfordia cxlata is figured as the generic illustration on PI. III.) Lingulella Hall and Clarke (in part), 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, pp. 55-59. (The genus Lingulella is described and discussed, but figures of Obolus (Westonia) ella accompany the text, and Botsfordia cxlata is figured as the generic illustration on PL II. Species belonging with other genera are also mentioned as belonging to Lingulella.) Mobergia Redlich, 1899, Mem. Geol. Survey India, Paleontologia Indica, new ser., vol. 1, No. 1, Cambrian Fauna of the Eastern Salt Range, pp. 5-6. (The description of this new genus is incorporated with that of the new species " Mobergia granulata.") Botsfordia Matthew, Waloott, 1908, Smithsonian Misc. Coll., vol. 53, No. 4, PI. XI, and pp. 142 and 145. (Classifi- cation of genus.) General form moderately convex, subcircular, with the ventral valve more or less obtusely acuminate and the dorsal valve oval. Ventral valve with the beak (apex) close to the pos- terior margin, perforated with a minute pedicle opening that is separated from the posterior margin by a very short listrium; posterior margin arched above the plane of the side and front margins of the valves. Dorsal valve with a minute beak at the margin. Surface with concentric lines and ridges of growth and a more or less regular system of tubercles resting upon concentric, rounded, regular or irregular, separate or inosculating ridges; the tuberculated or granulated surface may cover the entire shell or only a portion of it; the tubercles may be arranged in regular order, as in Botsfordia fulchra (Matthew) (PI. LXII), or irregularly, as in B. granulata (Redlich) (PI. LVII). The shells are small, rarely exceeding a length of 12 mm. Substance corneous, or phos- phate of lime and chitin. Structure of shell lamellated, the inner lamellae being more or less oblique to the outer layer. Interior of ventral valve with a small visceral area not exceeding one-half the length of the valve ; the pedicle opening is at the posterior end of the visceral area, where the shell usually has its greatest thickness. Vascular sinuses strong, and well within the body of the valve. Muscle scars arranged essentially as in Oholus; the transmedian and anterior lateral are close to the main vascular sinus and well back toward the posterolateral part of the valve. So far as known; the centrals and the middle and outside laterals are grouped on each side of the front of the visceral area. Interior of dorsal valve much like that of Acrothele, except that the transmedian muscle scars are separable from the outside and middle lateral scars in one species, Botsfordia gran^ ulata (Redlich) ; otherwise they appear to be grouped within the cardinal muscle scar. Median ridge long and prominent; main vascular sinuses well developed and well within the sides of the valve; visceral area in the adult usually not more than one-half the length of the valve; central and anterior lateral muscle scars near the center of the valve. Type. — Obolus pulcher Matthew. a The synonymy f jr this genus does not give a complete record of the various nenera under ivhieh the species now included in Botsfordia were formerly placed; it gives only those references in which the genus is discussed or described. To complete the record the following mere generic references are listed; Orbicula Hall [1847, p. 290]. Brachiopode, nouv. gen. [de Vemeuil and Bar- rande, 1860, p.5.%1. Obolella iOrbicula) Ford [1871, p. 33]. Obolella Billings [1872a, p. 218]. Lingulella Walcott [1886b, p. 95; 1887, p. 199]. Lingulella? Matthew [1888, p. 28]. Obolus Matthew [1889, p. 306; 1890, p. 151]. Lingulella Walcott [1891a, p. 607]. Obolus? Hall and Clarke [1892c, pp. SI and 183]. Obolus (^Botsfordia) Matthew [1894, p. 90; 1895a, p. Ho]. Lingulella Matthew [lS95a, p. 126]. Acrothele Pompeckj [lS96b, p. 603]. Obolus (Lingulella) Walcott [1901, p. 688]. Obolus (Botsfordia) Matthew [1902e, p. 95]. 602 CAMBRIAN BRACHIOPODA. Matthew [1895a, PI. Ill] has given diagrammatic illustrations and elaborate descriptions of a number of "embryonic" characters of Botsfordia pulchra. Prof. W. A. Parks, of the University of Toronto, sent me (in July, 1906) all the material in the Matthew collection representing this genus and species, but I was unable to recognize the originals from which Matthew's drawings were made. It does not seem probable that his figures 2a, 2b, and 2c represent a young shell of this genus, as it is represented with a high false area similar to that of some species of Acrothele; the same is true of figure 2g. Of the other figures, Ik, 2k, and 2i appear to be the posterior portions of adult shells from which the anterior portions have been broken away. There are two slabs of rock in the Matthew collection upon which there are a number of distorted and poorly preserved interiors of the valves, some of which may have been used in constructing restorations of the interior characters. Matthew [1891, p. 148] regarded Botsfordia as a subgenus of Oiolus, as he did not dis- cover that the ventral valve was perforated with a pedicle opening and that the dorsal valve was much like that of Acrothele. Redlich [1899, pp. 5-6] proposed the genus Mobergia for a generically similar species, therefore his name becomes a synonym of Botsfordia. Redlich [1899, p. 6] compares Mohergia with Oholella, an observation that was based on keen appre- ciation of the cleft or pedicle groove and the arrangement of the muscle scars in the ventral valve; the dorsal valve he compared with that of Acrothele. He said [1899, p. 6]: "The agree- ment goes so far that we may consider Oholella crassa [Walcott, 1886b, p. 114] and Acrothele granulata [Linnarsson, 1876, p. 24] as the extreme forms of Mohergia." The difference between the ventral valves of Oholella crassa (Hall) and Botsfordia is that in the latter the pedicle groove and area have disappeared and a narrow listrium takes the place of the area, the pedicle open- ing passing through the shell, while in Oholella the pedicle opening is above a clearly defined area. The dorsal valve of Botsfordia is more like that of Acrothele. The young shells of Oholella may have been provided with a pedicle opening in the young stages of growth, much like that in the adult stages of Botsfordia. Botsfordia appears to be a primitive form of Acro- tretidse to the extent that the false area of the ventral valve is only a thin band between the pedicle opening and the posterior margin, whereas in Acrotreta there is a well-developed false area. Botsfordia appears to represent the first, or, at least, an early stage between the open pedicle furrow of Oholus and the inclosed pedicle tube of Acrothele and Acrotreta. Botsfordia differs from Acrothele by the form of its visceral area and position of the main vascular sinuses in the ventral valve, also the position of the pedicle opening. The cancellated surface of Botsfordia pulchra (Matthew) is similar to that of Micromitra (Iphidella) pannula (White) (compare PI. LXII, figs. 5, 5a-c, with PI. IV, figs. Is, It). The forms of surface in B. granulata (Redlich) and B. cselata (Hall) are often found in species of Oholus {Westonia) and Lingulella (Lingulepis) (Pis. XLIV, XLVII). The surface of Acrothele (Redlichella) granulata (Linnarsson) (PI. LVI) is similar to that of Botsfordia granulata (Redlich) (PL LVII). In Schizopholis rugosa Waagen the false cardinal area is more developed than in Botsfordia, and the apex is elevated. Schizopholis appears to be a form intermediate between Botsfordia and Acrotreta. At present the species of Botsfordia known to ine are B. pulchra (Matthew), B. cselata (Hall), B. granulata (RedUch), and B.? harrandei Walcott. Botsfordia? bakbandei Walcott. Plate LVII, figures 7, 7a-b. BracMopode nouv. gen. de Verneuil and Bakrande, 1860, Bull. Soc. g6ol. France for 1859-1860, 2d ser., vol. 17, pp. 536-537, PI. VIII, figs. 5, 5a-e. (Described and discussed in French as a new species. Figs. 5, 5a-b are copied in this monograph, PI. LVII, figs. 7, 7a-b, respectively.) Acrothele Pompeckj (in part), 1896, Jahrb. K.-k. geol. Reichsanstalt for 1895, Bd. 45, Hft. 3, p. 603. (Discussed in German, changing generic reference; see p. 603 for translation.) Botsfordia? harrandei Walcott, 1908, Smithsonian Misc. ColL, vol. 53, No. 3, pp. 77-78. (Discussion in the preced- ing reference translated and species described and discussed as on p. 603 as a new species.) OBOLELLID^. 603 Of this species Pompeckj [1896b, p. 603] writes: From Barrande's description and figure it is not quite easy to interpret this species. I have before me several specimens of a brachiopod from Coulouma, in the Department of H6rault, which Miquel [1893, p. 9] mentioned as "la Disdna." I regard this south French form as belonging to the genus Acrothele, and believe that it is probably identical with the species mentioned by de Verneuil, Barrande, and Barrois as occurring in Spain. Having before me the specimens which Miquel collected, and which I have named Acrothele iergeroni (PI. LVIII), I do not think they can be considered the same as the form described by de Verneuil and Barrande. (Compare PI. LVII, figs. 7, 7a-b with PI. LVIII, figs. 6, 6a-c.) From Barrande's description and illustration the following note is written: The shell is about as wide as long, suboval, with pointed beaks; valves moderately convex, with the ventral a little more so than the dorsal. There is a small area on each valve, but no trace of a triangular false deltidium. Beak of ventral valve with a minute pedicle opening. Surface ■with fine, distinct, concentric strise. Substance of shell calcareous. A shell 13 mm. in length has the same width, and the thickness of the two valves united is 5 mm. Barrande thought that a new genus was indicated, but in the absence of interior characters decided not to name the genus or species. The perforate ventral valve and area suggested Siphonotreta to him, but the calcareous shell was opposed to it. I have referred the shell to the genus Botsf or dia provisionally and named it after Barrande, whose memory all paleontologists take pleasure in recaUing. The reference to Botsfordia is made on account of: (a) the subacuminate ventral valve with minute pedicle opening above a false cardinal area unmarked by a false deltidium; (b) the convex ventral and dorsal valve; (c) the tendency of Botsfordia pulchra Matthew to have the substance of its rather thick shell replaced by calcareous matter. I have attempted to secure specimens of tliis shell, but unsuccessfully. Until further information can be secured the present reference vdll serve to indicate the probable relation- ship of the species. Formation and locality. — Middle Cambrian: (350 [de Verneuil and Barrande, 1860, p. 538]) Red limestone of the Paradoxides zone, near Adrados, north of Sabero and Bofiar, Gantabrian Mountains, Province of Leon, north- western Spain. Botsfordia c^lata (Hall). Plate LIX, figures 1, la-q, 3, 3a-b. Orbicula aetata Hall, 1847, Nat. Hist. New York, Paleontology, vol. 1, p. 290, PI. LXXIX, figs. 9a-c. (Described and discussed as a new species.) Obolella (Orbicula) caslata (Hall), Ford, 1871, Am. Jour. Sci., 3d ser., vol. 2, p. 33. (Merely changes generic reference.) Obolella cxlata (Hall), Billings, 1872, Canadian Naturalist, 2d ser., vol. 6, No. 2, p. 218. (Merely changes generic reference.) Idngulella cselata (Hall), Ford, 1878, Am. Jour. Sci., 3d ser., vol. 15, pp. 127-128. (Described and discussed.) Idnguklla cxlata (Hall), Walcott, 1886, Bull. U. S. Geol. Survey No. 30, p. 95, PI. VII, figs. 1, la-d. (Copies the first paragraph of Hall, 1847, p. 290, copies Ford, 1878, pp. 127-128, and discusses species. The specimens represented by figs, lb and Id are redrawn in this monograph, PL LIX, figs. Ic and lo, respectively.) Idngulella exlata (Hall), Walcott, 1887, Am. Jour. Sci., 3d ser., vol. 34, p. 199, PI. I, fig. 16, opposite p. 240. (The description of the plate is on p. 199.) Idngulella cselata (Hall), Walcott, 1891, Tenth Ann. Kept. U. S. Geol. Survey, p. 607, PI. LXVII, figs. 1, la-e. (Localities mentioned. Figs. 1, la-d are copied from Walcott, 1886b, PL VII, figs. 1, la-d, respectively. Fig. le is copied from Walcott, 1887, PL I, fig. 16.) Lingulella cselata (Hall), Hall and Clarke, 1892, Eleventh Ann. Rept. State Geologist New York for 1891, PL III, figs. 1^. (No text reference.) Idngulella cselata (Hall), Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, pp. 57 and 58, PL II, figs. 1—4. (Mentioned in the text. Figs. 1-4 are copied from figs. 1-4 of the preceding reference.) Idngulella {f) ccelata (Hall), Matthew, 1895, Trans. New York Acad. Sci. for 1894-95, vol. 14, p. 126. (Specimens from a new locality characterized and discussed.) Obohis (Lingulella) bicensis Walcott, 1901, Proc. U. S. Nat. Mus., vol. 23, p. 688. (Described and discussed as a new species.) General form elongate ovate and varying from broad oval to oval acuminate. Ventral valve naoderately convex with the longitudinal line nearly flat from a short distance in front of 604 CAIMBRIAN BRACHIOPODA. the apex nearlj- to the front margin in old shells ; in young shells it rises with a gentle slope from the front margin to the umbo; the posterior margin, including some distance along the cardinal slopes, rises and arches gently above the plane of the edges of the front and sides of the valve, which brings the apex or beak close to the posterior margin (PI. LIX, fig. lb) ; pedicle opening small and at the point of the apex or beak. Dorsal valve more broadly ovate in outline than the ventral, moderately convex, and rather strongly arched toward the beak, wliich is marginal; the arching of the posterior portion of the valve causes it to fit closely into the upward arching posterior margin of the ventral valve ; a shallow median sinus of varying strength and width extends from the umbo toward the front margin, where it usually disappears. Surface highly ornamented by narrow, closely arranged, concentric, elevated, irregular, and often inosculating hnes, on which small round pustules are lined in such a manner as to give a beaded effect to the surface. The width of the ridges and size of the pustules vary on shells from the same localities and from different localities. Often the sliells have been worn by attri- tion so as to be almost smooth, tlie coarser stria; and lines of growth alone remaining; in addi- tion some shells have more or less numerous, rounded, depressed, radiating ridges, which may be quite regular (PI. LIX, fig. Ih) or very irregular and discontinuous (PL LIX, fig. Ic) ; some shells are without traces of the radiating ridges and others have only the faint outUnes of them. The inner layers are usually shiny and marked by concentric lines and striae, and numerous fine radiating striae. Shell substance corneous ; shell rather thin when young, increasing to a rather strong shell in large specimens; it is built up of a rather tMn outer layer and several inner laj^ers or lamellae. The largest ventral valve has a length of 10 mm., width of 8 mm., toward the anterior margin; as tliis shell has been broken near the beak and also at the anterior margin, it probably had a length of 12 to 13 mm. The interior of the ventral valve shows strong main vascular sinuses, which originate near the pedicle opening, and gradually separate as they extend forward into the valve; beyond the center they curve shghtly inward and terminate about the anterior fifth of the length of the valve. A small visceral area extends a short distance forward between the main vascular sinuses; it has a narrow depressed space across the front (PI. LIX, fig. Ig) that indicates the position of the central, outside lateral, and middle lateral scars; the furrow that extends from near the center of the visceral area to the pedicle opening near the posterior margin is clearly indicated on figure le; as tlie pedicle opening was at the extreme end and with only a very narrow hstrium between it and the posterior margin, the cast of it, or any trace of it, is very difficult to find ; tliis is rendered doubly so by the thin posterior portion of the shell breaking off both before being embedded in the sediment and when being worked out of the rock. There may have been a narrow area, but it has not been seen, and nothing definite is known of the muscle scars. The interior of the dorsal valve shows a short narrow area, from which a rather broad, low, median ridge extends forward beyond the center of the valve; a narrow septum is indicated along the posterior portion of the ridge; strong main vascular sinuses originate beside the median ridge at the back and diverge gradually as they extend into the valve; the position of the central and lateral muscle scars appears to have been the same as in Oholus (PI. LIX, fig. 1 1), but they have not been clearly distinguished except one central scar (li) ; the cardinal muscle scars are large and situated outside of the main vascular sinuses about their awn length in advance of the area. Observations. — This species, Uke Botsfordia granulata (Redlich), is characterized by having the pedicle aperture close to the posterior margin; it also has the same Obolus-hhe arrangement of the visceral area, vascular sinuses, and muscle scars in the ventral valve; it differs in outline, surface, and interior markings from B. granulata. When studying the genus Lingulella in 1898 I left Lingulella cselata (Hall) out of the list of species of Lingulella [Walcott, lS98b, p. 393], as I was satisfied that it did not belong there, but OBOLELLID^. 605 it was not until the study of Botsfordia Mattliew was taken up that a satisfactory generic reference was estabhshed. The shell appears to have been easily broken, as it is very difhcult to obtain good specimens, especially of the ventral valve. It was 10 years or more after I began collecting it before a ventral valve was found showing the pedicle opening. In 1901 I described a young shell of this species as Oholus (Lingulella) hicensis [Walcott, 1901, p. 688]. By comparison with other small shells from the type locality at Troy, New York, I am satisfied that the Bic specimen is a young shell of B. cselata. Botsfordia cxlata is widely distributed in the Lower Cambrian rocks of the St. Lawrence River, Lake Champlain, and Hudson River valleys, and it is one of the oldest of the Cambrian brachiopods of the Atlantic pro\ance of eastern North America. At Troy, and in Wasliington County, Nev/ York, it is associated with the trilobites FMipto- cepTiala asapJioides Emmons and Conocoryphe trilineata (Emmons) of the Lower Cambrian fauna, and in the Georgia, Vermont, section it is 700 feet lower than Olenellus tJiompsoni (Hall) . Formation and locality. — Middle Cambrian : (308e [Matthew, 1895a, p. 126]) Beds of Division Clbl of Matthew's [1895a, p. 108] Protolenus zone, on Hanford Brook, St. John County, New Brunswick. Lower Cambrian: (2o) Limestone bowlders in conglomerate, on shore at east entrance to harbor at Bic; (2r) limestone bowlders in a conglomerate in a cut on the Intercolonial Railway, 2 miles (3.2 km.) west of Bic railway station; and (2p) limestone on south side of road a little west of Bic and half a mile (0.8 km.) west of the road leading to the wharf; all in Rimouski County, Quebec, Canada. (392c) At the Straits of Belleisle, Labrador. (319j) Sandstone 50 feet (15 m.) above the base of the section west of Parker's quarry and about a mile (1.6 km.) from the shore of Lake Champlain, in the township of Georgia, Franklin County, Vermont. (29a) Limestone 1 mile (1.6 km.) below the New York Central Raih-oad depot at Schodack; (2b) limestone just north of Beman Park, m the northeastern part of the city of Troy, Troy quadrangle (U. S. Geol. Sm-vey): (367i [Hall, 1847, p. 290]) shales near Troy; and (27) even-bedded and conglomerate limestones on the ridge in the eastern suburb of Troy, Troy quadrangle (U. S. Geol. Survey); all in Rensselaer County, New York. (33) Limestone on the roadside near Rock Hill schoolhouse near North Greenwich, about 5 miles (8 km.) north- northeast of Greenwich; (33b) limestone on M. C. Tefft's farm, 1.5 miles (2.4 km.) east-southeast of North Greenwich, about 5 mUes (8 km.) north-northeast of Greenwich; (36b) limestone near schoolhouse No. 12, near Greenwich; (39a) limestone 0.25 mile (0.4 km.) north of Easton Station, 3 miles (4.8 km.) south of Greenwich; and (43a) limestone 1 mile (1.6 km.) east-northeast of Salem; all in the Cambridge quadrangle (U. S. Geol. Survey), Washington County, New York. (34a) Limestone 1 mile (1.6 km.) west of North Hebron, 5 mUes (8 km.) south-southwest of Granville; (38) limestone 0.25 mile (0.4 km.) north of John Hulett's farmhouse about 3 mOes (4.8 km.) west of South Granville and 4.5 miles (7.2 km.) southwest of Granville; and (38a) limestone 2 mUes (3.2 km.) south of North Granville, on the road which turns south from the road running between that vUlage and TruthvUle, 4 mUes (6.4 km.) west-northwest of GranvUle; all in the Fort Ann quadrangle (U. S. Geol. Sm-vey), Washington County, New York. (38c) Shale at the slate quarries on the west side of the valley 1 mile (1.6 km.) north of Middle GranvUle, Mettawee •quadrangle (U. S. Geol. Survey); (34) limestone on roadside a little west of the bridge over Poultney River at Low Hampton, about 5 mUes (8 km.) east-northeast of Whitehall, Whitehall quadrangle (U. S. Geol. Survey); (35) Limestones 1.5 mUes (2.4 km.) north of Bald Mountain and 3.5 mUes (5.6 km.) north-northwest of Greenwich, Schuylerville quadrangle (U. S. Geol. Sm-vey); (35a) shaly limestone on the west slope of the summit of Bald Moun- tain, 3 miles (4.8 km.) north-northwest of Greenwich, SchuylervUle quadrangle (U. S. Geol. Sm-vey); (338h) lime- stone on the summit of Bald Mountain, about 2 miles (3.2 km.) northwest of Greenwich, SchuylervUle quadrangle (U. S. Geol. Survey); and (39) limestone south of the Delaware and Hudson railroad track, on the road running south- .southwest from Low Hampton, about 5 miles (8 km.) east-northeast of Whitehall, Whitehall quadrangle (U. S. Geol. Survey); all in Washington County, New York. Botsfordia geanulata (Redlich). Plate LVII, figures 4, 4a-r. Mobergia granulata Reduch, 1899, Mem. Geol. Survey India, Paleontologia Indica, new ser., vol. 1, No. 1: The Cambrian fauna of the Eastern Salt Range, pp. 5-6, PI. I, figs. 11-18. (The description and discussion of this new species is incorporated with that of the new genus "Mobergia.") General form subcircular, with the ventral valve very obtusely acuminate, and the dorsal valve transversely more or less broadly oval. Ventral valve moderately convex with the 606 CAMBRIAN BRACHIOPODA. longitudinal line nearly flat from the apex to beyond the center of the valve, where it slopes gently to the anterior margin; on some shells the slope to the apex rises more abruptly and there is a gentle slope from the umbo to the front margin; the posterior margin arches gently upward from the plane of the edges of the front and sides of the valve. Apex directed back- ward and perforated by a minute pedicle opening; it extends a little beyond the posterior margin, and is separated from it by a narrow false area or rim of shell ; on some shells an elongate, more or less crescentiform tubercle occurs on each side of the apex, and just back of them at the end of the depression between them the minute pedicle opening occurs, or there may be a thickening of the shell back of the opening which results in a tubercle, as shown in Plate LVII, figure 4d; in other shells there is simply a thickened rim of shell about the front and sides of the apex with the pedicle opening at the posterior section of it (PL LVII, fig. 4c). Dorsal valve moderately convex; it slopes rather abruptly from the umbo to the minute mar- ginal beak and gently to the front; a minute tubercle occurs on each side of the beak of perfect specimens (PI. LVII, fig. 4b). Surface marked by concentric lines of growth and low, rounded, more or less obscure radiating ridges that occur on the anterolateral portions, or on the central part, or all across in front of the umbo and sides, or only as faint traces; in addition there is a system of fiae undu- lating, irregular, more or less inosculating, concentric ridges, upon which there are minute rounded tubercles or granules that have no extended systematic arrangement; on some shells the granulated surface extends to the front margin and on others more or less of the front portion of the valves is marked only by concentric lines and traces of the undulating ridges; in some places the granules are arranged in diagonal lines that cross each other obHquely, and then the effect is a modified form of the surface of Botsfordia fulchra (Matthew). The following are measurements of the valves: Dimensions of valves of Botsfordia granulata {Redlich). Length. Width, mm. mm. Ventral 6.5 7.5 Ventral. 6.5 6.5 Dorsal 4 5 Dorsal 4. 5 5 The specimens are embedded in a fine shale and are more or less flattened by compression. The shells are built up of a tliin outer layer and several inner layers or lamellae slightly obHque to the outer surface. The shell substance is corneous or, according to the author, "phosphate of Hme and chitine" [Redhch, 1899, p. 6]. The interior of the ventral valve is essentially the same as that of Botsfordia palchra (Matthew) and B. cselata (HaU) ; strong main vascular sinuses rise beside the median line close to the posterior margin and gradually diverging, extend forward into the body of the valve nearer to the median fine than to the outer margins; the visceral area is about three-eighths the length of the valve and it has a narrow median groove that terminates in a club-shaped anterior end (PI. LVII, fig. 4g) that suggests the heart-shaped cavity of Oholus (PI. VII, figs. 1, 3, and 6). The position of the transmedian and anterior lateral muscle scars is shown close beside the main vascular sinus; the central scars and outside and middle laterals can not be separated but the space they occupy is indicated at c, Plate LVII, figure 4p. The cast of the pedicle passage through the sheU is shown in figure 4i. The interior of the ventral valve is much like that of Acrothele coriacea Linnarsson. (Compare PI. LVII, fig. 4k, with PL LVI, fig. le.) There is a median ridge with the main vascular sinuses starting out beside it near the posterior margin and gradually separating as they extend forward into the valve about halfway between the margins of the valve and the median ridge; the cardinal muscle scars are small and close to the median ridge, posterior margin, and main vascular sinuses ; the central muscle scars occur on the slope of the median ridge a little back of the center of the valve, and the small anterior laterals close to the median line a little in advance; in young shells the transmedian and middle and outside laterals are combined in OBOLELLIDiE. 607 one scar (cl, PI. LVII, fig. 4k), but in a larger shell the transmedian scars are separated back oi the middle and outside lateral scars, which can not be distinguished as separate scars. Observations. — Redlich [1899, p. 5] proposed the genus "Mobergia' ' for tliis species. This was well done, but Matthew [1891, p. 148] had previously described Botsfordia. Botsfordia granu- Tata (Redlich) has the same type of interior in both valves as B. pulchra (Matthew), and the granulated surface is of the same general type except that it is more completely developed in B. pulchra. There is a strong generic relation to Botsfordia csdata (Hall) but the specific differ- ences are very decided. Doctor Holland, director of the Geological Survey of India, kindly sent me the type speci- mens of this species, and through the courtesy of Dr. Fritz Noetling, I obtained for the United States National Museum a fine collection of this species from the Salt Range. FoKMATiON AND LOCALITY. — Middle Cambrian: (15r)a Dark argillaceous shales, at Khussak, Salt Range, India. Botsfordia pulohra (Matthew). Plate LXII, figures 5, 5a-l. Lingulella (?) cf. Lingula favosa Linnarsson, Matthew, 1888, Canadian Rec. Sci., vol. 3, No. 1, pp. 28-29. (Mentioned.) Obolus ■pulcher M.\tthew, 1889, idem, vol. 3, pp. 306-307, figs. 1-8, p. 306. (Described and discussed as a new species.) Oholu^ pulcher Matthew, 1890, Trans. Roy. Soc. Canada for 1889, 1st ser., vol. 7, sec. 4, No. 12, pp. 151-155, PI. VIII, figs, la-m, 2a-l. (Description given by Matthew, 1889, pp. 306-307, copied, and species described and discussed in great detail. Figs, la-c and 2a-c are copied from figs. 3-8, respectively, of the preceding reference.) Oholus {Botsfwdia) pulcher Matthew, 1891, idem for 1890, vol, 8, sec. 4, No. 6, p. 148. (Mentioned,) Obolus {Botsfordia) pulcher M.\tthew, 1892, idem for 1891, vol. 9, sec. 4, No. 5, pp. 62-63. (Discussed, the new sub- ~ generic name being proposed on page 63.) Obolus? pulcher Matthew, Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, p. 81, PL IV k, fig. 22. (Characterized, questioning generic reference.) Obolvs? pulcher Matthew, Hall and Clarke, 1892, idem, p. 183. (Characterized and discussed, copying Matthew's notes, 1890, p. 154, on the stages of growth and development. Calls attention to resemblance of this species, in growth stages, to Kutorgina.) Oholus (Botsfordia) pulchra M.^tthew, 1894, Trans, Roy, Soc. Canada for 1893, 1st ser., vol. 11, sec. 4, No, 8, pp. 90-91, PL XVI, figs. 3 and 3b. (Described and discussed.) Obolus (Botsfordia) pulchra Matthew, 1895, Trans. New York Acad. Sci. for 1894-95, vol. 14, pp. 115-121, PL III, figs, la-i, Ik, 2a-g, 2i, and 2k (the missing figures are lacking in the reference; they have not been referred elsewhere in this monograph), (With the exception of the note on the horizon in the first paragraph, the text is copied from Matthew, 1890, pp. 151-155. Figs, la-i, 2a-g, and 2i are copied fi-om Matthew, 1890, PL VIII, figs. la-i, 2a-g, and 2i, respectively. Figs. Ik and 2k are copied from Matthew, 1894, PL XVI, figs. 3b and 3, respectively.) Obolus (Botsfordia) pulcher Matthew, 1902, Trans. Roy, Soc. Canada for 1902, 2d ser., vol. 8, sec. 4, No. 3, p. 95, PL I, figs. 7a-b. (Characterized and discussed.) General outline subcircular; the ventral valve being obtusely acuminate and the dorsal a little wider than long. Ventral valve gently convex, most elevated at or a little in front of the apex; apex close to the posterior margin and pointed backward; there is a minute pedicle aperture at the end of the apex. The posterior margin of the valve is arched upward so as to leave only a narrow rim between the margin and the pedicle aperture. Dorsal valve moderately convex, more arched toward the front in old shells, and in all shells it arches upward at the posterior margin so as to fit closety against the margin of the ventral valve. Surface marked by concentric lines of growth that form imbricating ridges at irregular intervals. In addition there is a reticulated surface formed by the presence on the rounded concentric ridges of small tubercles that are rounded quadrilateral in outline and that alternate on the adjacent ridges, so that each tubercle falls opposite the space between the two tubercles in front; this results in rows of tubercles that are apparently arranged in oblique rows extending from the posterolateral margin of the shell on each side obliquely forward to the margin of the shell on the opposite side; the depressions between the tubercles unite and serve to increase the appearance of an oblique reticulate, tuberculated surface; the tubercles are low at the back and high in front. The finely cancellated surface is usuallj^ on the posterior half of the shell, the tubercles becoming scattered and often entirely absent over a Specimens from the type locality were given to tlie United States National Museum and this number was assigned to them. 608 CMIBRIAN BRACHIOPODA. the anterior and lateral portion of the valves. The interior layers and interior surface show numerous fine, radiating strife, and there are also a few radiating lines on the anterior portion of the adult shells. The shell is built up of a thin outer layer and numerous inner layers or lamellae that are obhque to the outer surface; the obhque layers on the front portion and sides of adult shells terminate at the growth lines, so as to give an imbricated appearance to the surface. Shell substance apparently corneous. A large ventral valve has a length and breadth of 11.5 mm. A dorsal valve 10 mm. long has a width of 12 mm. These proportions vary slightly in different shells. The interior of the adult ventral valve is much like that of Botsfordia cselata (Hall). It has a short visceral area between distinctly marked main vascular sinuses that originate one on etich side of the median line at the posterior margin, and gradually separate as they extend forward into the valve; no distinct muscle scars have been seen in this valve. The interior of the dorsal valve has a long central ridge extending well toward the front of the valve; at about the center it shows a tendency to bifurcate; the main vascular sinuses originate at the median line near the posterior margin and arch rapidly outward on each side and then obliquely forward into the body of the valve; the muscle scars are represented by an elongate cardinal scar on each side near the main vascular sinus, where it curves forward into the valve; also one centr;^ muscle scar on each side of the median ridge a little back of the center of the valve. Under the description of the genus Botsfordia I have referred (p. 602) to the description of the interior of this species by Matthew. I have given above all I can observe on the specimens in the Matthew collection now at the University of Toronto, also on the specimens in the col- lection of the United States National Museum. Observations. — This species is so clearly distinct from Botsfordia cseJata (Hall) and B. granr- ulata (Redlich) that comparison is unnecessary. It agrees with both of the latter species in having the perforated apex of the ventral valve separated from the posterior margin by a narrow rim of shell, also in having a short visceral area and strong main vascular sinuses. The dorsal valves are of the same general type. Formation and locality. — Middle Cambrian: (2y) Sandstone about 25 feet (7.6 m.) above the Lower Cambrian, on the southeast side of Catons Island; and (308d [Matthaw, 1894, p- 1^1]) sandstones of Division Clh2-4 of Matthew's section on Catons Island; both in Long Reach, St. John River, Kings County, New Brunswick. Genus SCHIZOPHOLIS Waagen. [oxiC This date (1892) is taken from the title-page and is used throughout this monograph, but the work is clearly antedated, the correct date being 1893 or 1894. 616 CMIBRIAN BRACHIOPODA. length of the depression; traces of a median septum occur in the dorsal valve. Tlie grooves of the main vascular canals begin in each valve at the front margin of the area and arch out- ward and forward, and then, after passing the center of the valve, curve gently inward, termi- nating toward the front of the valve; only traces of the secondary radial canals have been observed. The course of the parietal scar in each valve is probably much like that of Obolus. The muscle scars, as far as known, are essentially the same as those of Oholus. In the ventral valve the transmedian (i) and anterior laterals (j) occur just outside of the line of the main vascular canals. The position of the outside (1) and middle (k) laterals and central (h) scars is within the areas (c) on each side of the anterior termination of the median depression. In the dorsal valve the centrals (h) and anterior laterals (j) are clearly defined, and the position of the transmedian (i) and outside laterals (1) is indicated. The umbonal scars are small and are situated in the ventral valve close to the sides of the anterior end of the furrow in the area; they have not been recognized in the dorsal valve. Pedicle muscle scars unknown. Type. — Trematoholus insignis Matthew. Observations. — The above description is quite unlike that given of this genus by Matthew [1893a, p. 276]. It is drawn up from specimens of Trematoholus insignis, lent to me, first by Dr. Matthew, and later by Prof. W. A. Parks of the University of Toronto, and a fine series of specimens collected by Mr. S. Ward Loper for the United States National Museum at the type locahty. I find that the specimen illustrated and described by Matthew [lS93a, p. 276, fig. la] as the interior of the ventral valve is a natural cast of the exterior of a ventral valve, preserv- ing the cast of the area and the elongate depression formed by the advance of the pedicle opening, and that his dorsal valve (lb) is the cast of the interior of a ventral valve. The type specimen of Matthew's ventral valve [1893a, p. 276, fig. la] is illustrated by Plate LXXXIV, figure 5b, and tlie cast of it by figure 5c. The muscle scars illustrated by Matthew are slight irregularities that existed on the outer surface of the sheU, along the stronger lines of growth. The tj'pe specimen of Matthew's dorsal valve [1893a, p. 276, fig. lb] is illustrated by Plate LXXXIV, figure 5; it should be compared with the casts of the interior of the ventral valve of Trematoholus Icempanum (Matthew) as shown by Plate LXXXIII, figures Ic and Id. The generic relations of Trematoholus insignis Matthew and T Icempanum, the type of the genus Protosiphon Matthew [1897a, p. 68], may be seen by comparing Plate LXXXIII, figure 1, with Plate LXXXIV, figure 5c, and Plate LXXXIV, figures 5 and 5a, with Plate LXXXIII, figures Id and Ij. They appear to be generically the same. The specimens of Trematoholus insignis Ma.tihew a,nd Protosiplion pristinus (see Trematoholus pristinus (^Matthew)) came from the same stratum of rock and the same locality, and, with the correct understanding of the valves of the type specimens of T. insignis, they may be closely compared, as is done under the description of T insignis. Trematoholus is closely related to Schisamhon. The ventral valve in both genera has an oval pedicle opening in front of the beak at the anterior end of an external groove, tapering toward the beak; it is the progressive track of the pedicle aperture, and strong, arched lines indicate its successive positions in different stages of growth. (See PI. LXXXIII, fig. lo, which is a cast of the groove and opeiung in a tliick shell.) In Siphonotreta the pedicle opening is in front of the beak, but it does not advance with the growth of the shell as in ScTiizamhon and Trematoholus. The surface of Schizambon ia spinose wliile that of Trematoholus is nearly smooth. The shells of the latter are thick and the former relatively thin. The muscle scars, as far as known, are essentially the same in the two genera. It is interesting to note that, with the exception of the pedicle groove and opening, Trema- toholus and Oholella are closely related. The species now referred to the genus Trematoholus are: T. inMgnis Matthew, T. pristinus (Matthew), T. Jcempanum (Matthew), and T. excelsis Walcott. T excelsis occurs in the Lower Cambrian of eastern central California. It is one of the oldest of the Cambrian bracliiopods. The three species from New Brunswick are from near the base of the Middle Cambrian. SIPHONOTRETIDiE. 617 Trematobolus excelsis Walcott. Plate LXXXII, figures 8, 8a-b. Trematoholus exceUis Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, pp. 80-81, PI. VIII, fig. 8. (Described and discussed as below as a new species. Fig. 8 is copied in this monograph, PI. LXXXII, fig. 8.) Shell transversely oval in outline, with both valves obtusely acumiaate. Ventral valve strongly convex, with the minute beak at the posterior margin above a low area; the slope from the highest point of the valve, a little back of the center, is greatest toward the beak and nearly uniform to the front and sides of the valve. Pedicle opening unknown, as no exterior or cast of the exterior of the valve occurs in the material collected; two casts of the interior show the cast of the foramen at about the same position as in T. insignis Matthew and other species of the genus. Dorsal valve slightly more transverse than the ventral and about two-thirds as convex; a very slight median flattening occurs at the anterior margin that extends back on the valve, nearly to the beak in some specimens; otherwise the convexity is distributed as in the ventral valve. Surface marked by a few concentric lines of growth. The shell is rather thin, except over the umbonal and posterior portions of the ventral valve, where it is moderately thick. Its substance is now calcareous, and appears like that of T. insignis; the original shell may have been calcareocorneous. A ventral valve 18 mm. in length has the same width; a large dorsal valve 22 mm. long has a width of 27 mm. The area of the ventral valve is short and divided midway by a depressed subtriangular false pedicle furrow; the presence of pits on each side of the anterolateral margms of the false pedicle furrow indicates that the area at these places projected in the same manner as that of T. insignis Matthew and T. kempanum (Matthew). (Compare PI. LXXXII, fig. 8, with PI. LXXXIII, fig. Ic, and with PI. LXXXPV, fig. 5.) The cast of the interior of the ventral valve shows a median ridge with the cast of the pedicle opening at about the posterior sixth of the length of the valve; only the imperfect outlines of the splanclinocoele are Icnown; the main vascular sinuses are outHned for a short distance back of the transverse center suffi- ciently to indicate that their position was about the same as in T. kempanum. The position of the anterior lateral (j) muscle scar is clearly shown just outside of the main vascular sinuses; it is elongate oval in outline and a little in advance of the transmedian scar (i) ; the umbonal muscle scars are close to the median furrow, as in T. Tcempanum. Interior of dorsal valve unknown. Observations. — This fine species differs from all other known species of the genus in having the ventral valve more convex than the dorsal and m its greater size. It is the oldest species of the genus, occurring as it does well down in the section of the Lower Cambrian strata, in association with Olenellus. There are a large number of specimens of the exterior of the dorsal valve, but only two interior casts of the ventral valve. The dorsal valve of T. pristinus (Matthew) and T. Tcempanum (Matthew) also greatly outnumbers the ventral valve in the collections. This circumstance may be owing to the presence of the foraminal furrow and interior median furrows; these would cause the shell of the ventral valve to break more readily than that of the dorsal. Formation and locality. — lower Cambrian: (53) Sandstones in the lower portion of 3d of the Waucoba Springs section; (312) sandstones of 3d of the Waucoba Springs section; and (312a) shales of 3b of the Waucoba Springs section; all east of the Saline Valley road, east of Waucoba Springs [see Walcott, 1908f, p. 187, for position in section], Inyo County, California. (176 and 178a) Shales and interbedded limestones between massive limestones containing Archxocyathus at the south end of Deep Spring Valley; and (176a) sandstone on ridge east of the head of Mazouka Canyon, Inyo Range; both in Inyo County, California. Trematobolus insignis Matthew. Plate LXXXIV, figures 5, 5a-c. Trematobolus insignis Matthew, 1893, Canadian Rec. Sci., vol. 5, pp. 276-279, figs, la-d, p. 276. (Described and discussed as a new species. The specimens represented by figs, la and lb are redrawn in this monograph, PI. LXXXIV, figs. 5b and 5, respectively. Figs. 5c and 5a of this monograph are drawn from casts of the typical specimens, Matthew, 1893a, figs, la and lb, respectively.) 618 CM'IBRIAN BRACIIIOPODA. Trematobolus insignis Matthew, Hall and Clarke, 1892," Eleventh Ann. Eept. State Geologist New York for 1891, p. 252, fig. 263. (No text reference. Figs. 263 (la-d) are copied from Matthew, 1893a, figs, la-d, respectively, p. 276.) Trematobolus insignis Matthew, Hall and Clarke, 1892, o Forty-fifth Ann. Kept. New York St;ate Museum for 1891, p. 568, fig. 263. (Copy of preceding reference.) Trematobolus insignis Matthew, 1894, Trans. Roy. Soc. Canada for 1893, 1st ser., vol. 11, sec. 4, No. 8, pp. 88-90, PI. XVI, figs. 4a-d. (Except for the last paragraph, this is a copy of Matthew, lS93a, pp. 276-279. Figs. 4a-d are copied from Matthew, lS93a, figs, la-d, respectively, p. 276.) Trmatobolus insignis Matthew, 1895, Trans. New York Acad. Sci. for 1894-95, vol. 14, pp. 122-125, PI. IV, figs. 2a-d. (Text and figures copied from preceding reference.) Trematobolus insignis Matthew, 1895, Bull. Nat. Hist. Soc. New Brunswick, vol. 3, No. 13, p. 95, figs. la-d. (No text reference. Figs, la-d are copied from Matthew, 1895a, PI. IV, figs. 2a-d, respectively.) Trematobolus insignis Matthew, 1898, Bull. Nat. Hist. Soc. New Brunsmck, vol. 4, pt. 1, No. 16, p. 35, figs. la-d. (No text reference. Figs, la-d are copied from Matthew, 1895a, PI. IV, figs. 2a-d, respectively.) Shell svibcircular in outline, biconvex, valves inarticulate. Ventral valve gently convex, with the minute beak at the posterior margin, and above a low area. Pedicle opening a rather large, simple, oval opening at the anterior end of a furrow that gradually narrows toward the beak, where it terminates; from the lines of growth in the furrow indicating progressive stages of the advance of the foramen it is evident that the foramen began at or just in advance of the beak, and advanced with the growth of the shell in the same manner as the foramen of Schisam- ion (PI. LXXXIV, fig. 1) ; the length of the foraminal furrow varies from one-third to two- fifths of the length of the valve. The substance of the original shell appears to have been entirely removed by solution and replaced by the limestone. The closelj'' related species T. Icempanum (Matthew) has al calcareo- corneous shell. That the shell was strong is incHcated by the depth of the vascular markings and muscle scars. The outer surface is marked by a few concentric fines of growth. The type specimen is 9 mm. in diameter. The area of the valve is short and divided midway by a depressed, narrow, subtriangular space, bounded by narrow, slightly elevated ridges that originate just beneath the beak and diverge a little toward the margin of the area, where they unite with the margin and extend forward so as to form two short jDrojections, one on each side of the pseudopedicle furrow on the area; the area slopes forward from the beak at an angle of about 15°; it is marked by rather strong transverse lines of growth. There are no traces of the posterior portion of the foraminal furrow on the interior of the valve; it is entirely within the substance of the shell. The splanclinocoele extends to about the center of the valve; in front of the area a low, broad sweUing begins that extends forward beyond the foraminal opening, where it divides so as to leave a short depressed space, and witliin, a narrow median ridge; on each side and in front of the line of the pedicle opening there are the obscure outlines of the spaces occupied by the scars of the points of attaclunent of the central, middle lateral, and outside lateral muscles, very much as in Oholus (PI. VII) ; these muscle-bearing spaces are finely shown in T. Jcempanum (Matthew) and T. pristinus (Matthew) (PI. LXXXIII, figs. Id, Ij, 2c). The sinuses of the main vascular canals are broad and strong; they start near the front margin of the area near the median line and extend outward and forward subparallel to the outer margin of the valve to about the transverse median line, beyond winch, owing to the broken specimen, they have not been traced. The umbonal muscle scars occur on each side of the median line just beneath the projections of the area beside the false pedicle furrow; they are small and located on a low ridge. The transmedian and anterior lateral mus- cle scars are elongate oval in outline, close to the outer margin of the main vascular sinus, and placed on a rounded, low ridge; the transmedian scar extends a little outside of the anterior lateral scar at its anterior end; as already stated, the central scars and the middle and out- side lateral scars probably occurred in the spaces on each side of the anterior end of the low median ridge. a This date (1892) is taken from the title-page and is used throughout this monograph, but the work is clearly antedated, the correct date being 1893 or 1894. SIPHONOTRETIDiE. 619 The opening of the foramen in the interior of tlie valve is on the low naedian ridge at a point three-fifths of the distance from the area to the anterior end of the median line of the splanch- noccele (visceral area). Dorsal valve unknown. Ohservations. — This species is known only by the type specimens of Matthew. These include a matrix of the ventral valve, represented by Plate LXXXW, figure 5b, a cast of the interior of a broken ventral valve, figure 5, a fragment of the exterior of a ventral valve showing the foraminal furrow, and a fragment of the cast of the outer surface. As stated under the description of the genus, Matthew [1893a, p. 276] mistook the matrix of the ventral valve for the interior of a ventral valve, and the cast of the interior of a ventral valve for a dorsal valve. The true relations of the specimens are readity seen by comparing them with the speci- mens of closely alhed species on Plate LXXXIII." The type material was collected from a layer of rock that is identical with, or is nearly at the same horizon as, a layer at the same locality carrying numerous specimens of Trematoholus pristinus {=Protosip7ion pristinus Matthew). I would consider the latter a synonym were it not for the position and size of the vascular sinuses in the ventral valve, which are located well out toward the outer margin (compare PI. LXXXIV, fig. 5, with PI. LXXXIII, fig. 2c), wliile in T. pristinus they are much nearer the median line of the valve. The interior of the ventral valve of T. insignis is more like that of T. Tcempanum (Matthew). (Compare PI. LXXXIV, fig. 5, with PI. LXXXIII, figs. Ic, li.) Until a larger series of specimens representing T. insignis is collected the diagnosis of the genus must depend largely upon the material representuig T. Tcempanum. FoEMATiox AND LOCALITY. — Middle Cambrian: (301 fMatthew, 1895a, p. 123]) Sandstxjnes of Division lb2 of Matthew, on Hanford Brook, St. John County, New Brunswick, Canada. Trematobolus kempanum (Matthew). Plate LXXXIII, figures 1, la-o. Protosiphon Tcempanum Matthew, 1897, Geol. Mag., new ser., dec. 4, vol. 4, pp. 70-71, figs. 1-4, p. 70. (Described and discussed as a new species.) Protosiphon Tcempanum Matthew, 1898, Trans. Roy. Soc. Canada for 1898, 2d ser., vol. 4, sec. 4, No. 2, p. 131, PI. I, figs. la-f. (Text is almost an exact copy of the preceding reference. Figs, la-d are copied from figs. 2, 1, 3, and 4, respectively, of the preceding reference.) General form subcircular to rounded ovate, biconvex, with the dorsal valve about one- third more convex than the ventral; outhne of ventral valve obtusely acuminate and dorsal valve broadly roimded posteriorly. Beak of ventral valve marginal above a well-defined area; just in front of the beak a naiTow furrow starts that marks the path of advance of the pedicle opening; tliis furrow is usually from one-fourth to one- third the length of the shell and grad- ually \\adens and deepens up to the oval pechcle opening; strong fines of growth, with the curvature of the posterior side of the opening, mark the stages of growth and advance of the opening; these are beautifully shown by the cast of the furrow and opening illustrated by Plate LXXXIII, figure lo. The furrow and pedicle opening are entirely in. the layers of the shell and do not cause a projection on the interior of the valve; the opening is compressed in some specimens, but it is usually of good size, as is shown by a cast of it that extended from the outer to the inner surface; tliis is represented by figure le. The opening is of the same character as that of ScMzavnbon, except that it is through a thick shell. Dorsal valve proportionally a little shorter than the ventral; beak marginal. Surface marked by a few concentric fines of growth; the inner surface appears to have been smooth. The specimens are preserved in a fine-grained sandstone, and usuaUy in the form of casts; a few show portions of the shell, and these indicate that it was of a calcareo- corneous nature and built up of several rather strong layers or lamellae. This is also indicated by the cast of the pedicle furrow and opening (fig. lo). <■ I sincerely regret being obliged to differ so greatly with my friend Doctor Matthew on the interpretation of the types of this species and of the genus Trematobolus. 620 CAJVIBEIAN BRACHIOPODA. The largest ventral valve in the collection has a length of 14 mm. and a width of 13.5 mm. A dorsal valve 13 mm. long has the same wddth. The area of the ventral valve slopes backward and rises from the plane of the margins of the valve at an angle of about 45°. It is divided midway by a false pedicle area that varies in ^^^dth; it is subtriangular in outline, slightly depressed, and has a narrow median furrow of varjdng depth that is marked by strong lines of growth; on each side of the inner end of this furrow the area is extended forward as a toothlike projection, very much as in Bicia (PL L) and Obolella (PI. LV). The area is marked by transverse lines of growth sub- parallel to its anterior margin. The cast of the area (PI. LXXXIII, figs. Ic, Id, Ig, li, and Ik) shows the pits made by the projections of the area next to the false pedicle furrow; it was these pits in the cast of the ventral valve of T. insignis (PI. LXXXIV, fig. 5) that Matthew [1893a, p. 276] mistook for the dental sockets of the dorsal valve. The splanchnocoele of the ventral valve is large and clearly shown ; the low, broad, rounded median ridge is about one-half the length of the valve ; it broadens out near the pedicle opening and again toward the front; it is marked by a narrow median depression back of the pedicle opening, and, in front of the pedicle opening, by a central, elongate swell surrounded by a narrow furrow. The pedicle opening is clearly defined on nearly all casts of the valve; it is situated about two-fifths the distance from the area to the front end of the ridge on which it occurs. On each side, a short distance back of the front end, an area is outlined that extends obliquely backward to the main vascvdar sinu^; this area may be depressed below the general surface or raised above it; it corresponds to the area in the ventral valve of Oholus, in wliich the central muscle scars and the middle and outside lateral scars occur. (Compare PI. LXXXIII, figs. Ic, Id, with PI. VII, figs. 5 and 13; also with PI. XIV, figs, la and 4a.) The transmedian and anterior lateral muscle scars occur on a rounded ridge just outside of the main vascular sinuses (PL LXXXIII, fig. Id). The umbonal muscle scars are oval in outline and situated close to the posterior end of the central median ridge, and between the ridge and the trans- median muscle scars. The impressions made by the main vascular canals are broad, strong, and continued to the anterior third of the valve; they originate beside the median ridge close to the area, and curve outward and then inward beyond the center of the valve. The area of the dorsal valve is narrow and divided by a central, sHghtly depressed, tri- angular space; it is marked by transverse fines of growth and appears to be on the same plane as the margins of the valves. The splanclinocoele of the dorsal valve extends forward beyond the center of the valve; it is cUvided by a narrow, median septum, and has an oval depression in it a little back of the anterior lateral muscle scars; the central muscle scars are large, oval in outline, and situated on the outer slope of the rounded ridge about the central depression; the anterior lateral scars are small and placed on the rounded ridge in front of the central depression and close to the median septum. A low, rounded ridge extends obliquely forward into the valve from each side of the median septum; these probably mark the position of vascular canals extending forward from the visceral area; they are shown in Plate LXXXIII, figures 11 and In. The transmedian and anterior lateral muscle scars are located close to the outer edge of the main vascular sinus, well back on the posterolateral part of the valve. The main vascular sinuses start back of the visceral area near the median septum and curve outward and then forward about halfway between the central muscle scars and the margin at the center of the valve, and then a httle inward before terminating near the front margin. Observations. — ^This fine shell was the type of Matthew's genus Protosiphon [1897a, p. 68]. I find it to be congeneric with Trematobolus insignis Matthew, and rather closely related to that species. This may be seen by comparing Plate LXXXIII, figures Ic, Id, with Plate LXXXIV, figure 5. The pedicle furrow and aperture is much hke that of Schizamhon typicalis Walcott (PL LXXXIV, figs. 1, la) except that it is in a thick shell, wlule that of the latter species is in a relatively tlfin shell. In 1898 Mrs. Walcott and I collected a large series of specimens at the typical locahty, as I wished to illustrate fully this the oldest of the Siphono- tretidse of the ScTiizambon type. The shell occurs above the Olenellus zone, at about the same general horizon as T. insignis and T. pristinus. SIPHONOTRETID^. 621 The specific name was given in honor of Prof. J. F. Kemp, of Columbia University, New- York City. Formation and locality. — Middle Cambrian: (2u) Lowest beds exposed on the south side of Long Island; and (308g) shales of Division IbS or lb4 [Matthew, 1S97, p. 71] of Matthew's section on Long Island; both in Kennebecasis Bay [see Matthew, 1898a, pp. 124 and 127], St. John County, New Brunswick, Canada. Trematobolus pristinus (Mattliew). Plate LXXXIII, figures 2, 2a-h; Plate LXXXIV, figure 6. Obolus pristinus Matthew, 1895, Trans. New York Acad. Sci. for 1894-95, vol. 14, pp. 121-122, PI. IV, figs. la-d. (Described as a new species. The specimen represented by figui-e Ic is redrawn in this monograph, PI. LXXXIII, fig. 2f.) Obolus pristinus Matthew, 1902, Trans. Roy. Soc. Canada, 2d ser., vol. 8, sec. 4, No. 3, p. 96, PL I, figs. 8a-d. (Char- acterized. Figs. 8a-d are copied from figs, la-d, respectively, of the preceding reference.) General form biconvex, subcircular to short ovate. Ventral valve rounded acuminate, sometimes a Httle broader than long; beak marginal above a low area. Pedicle opening at the anterior end of a furrow thikt gradually narrows to the beak; the foraminal furrow varies in length from about one-third to two-fifths the length of the valve; it is situated in the thick- ened part of the shell and does not produce a ridge on the interior of the valve. Dorsal valve proportionally a httle shorter than the ventral; beak marginal; area, if present, unknown. Surface marked bj^ fine concentric striae and lines of growth that show as the front margins of imbricated lamellae of the shell; very fine radiating striae (also a few radiating, shghtly elevated lines) occur on some specimens, but whether they belong on the epidermal layer or one of the inner lameUse is unknown; the inner surface is shghtly roughened. The substance of the shell has been replaced by the calcareous matter of the matrix, but from the calcareo- corneous nature of the shell of T. kempanum (Matthew) it is probable that the original shell of this species was of the same nature. The shells vary in size from 5 to 13 mm. in length; the average is about 9 mm. The area of the ventral valve is short; otherwise, nothing is known of it. The splanch- nocoele extends nearly to the center of the valve; a low ridge starts near the area, and, gradu- ally widening, passes beyond the pedicle opening into an oval depression forming the anterior portion of the visceral cavity; the ridge back of the pedicle opening is marked by a slightly raised median line; the space on each side, between the median ridge and the main vascular sinuses, has a narrow band across the front that extends from each side of the central depressed area diagonally backward to the main sinuses; these bands correspond in position to the spaces occupied by the central muscle scars and the transmedian and outside lateral scars (compare PI. LXXXIII, fig. 2b, with PI. VII, fig. 13, of Obolus); the anterior lateral muscle scar is close to the main vascular sinus, nearly opposite the pedicle opening. . The main vascular sinuses start near the area on each side of the low median ridge, and, with a gentle outward curve, pass the center, and then, with a slight inward curve, reach nearly to the front margin; they do not extend laterally beyond a vertical fine drawn midway between the center and lateral margins of the valve. Fine, irregular, secondary radial canals extend outward from the main canal toward the margins. The splanchnoccsle of the dorsal valve extends beyond the center; a very narrow median septum is shown, or else a broad, low, rounded ridge. The main vascular sinuses start near the median line, close to the posterior margin, and curve forward, subparallel to the lateral margins of the valve, gradually getting farther away from the margins as they pass the trans- verse center of the valve. The central muscle scars are elongate oval in outline and situated back of the center of the valve; the anterior laterals are small and close to the median fine. Nothing is clearly shown of the details of the area of the dorsal valve; it was probably similar to that of T. Jcempanum (Matthew). (Compare figs. 2f and 2g with figs. 1 1 and Im, PI. LXXXIII.) Observations. — This species is closely related to T. insignis Matthew, reference to which is made under that species; it differs in the position of the main vascular sinuses of the ventral 622 CAMBRIAN BRACHIOPODA. valve, and in the size of the splanchnocoele. T. Icempanum is a larger shell with different vas- cular and other scars in the interior of the ventral valve. Figures 2, 2a-d represent specimens collected by S. Ward Loper for the United States National Museum, and figures 2e-h represent the specimens in Matthew's collection, now at the University of Toronto. Formation and locality. — Middle Cambrian: (301 [Matthew, 1895a, -p. 122]) Sandstones of Division IbS; (2h) sandstones of Di\-ision lb2; and (2i and 2k) sandstones of Di\'ision lb3; all in Matthew's [1895a, p. 108] Protolenus zone, on Haniord Brook, St. John County, New Brunswick, Canada. Genus SCHIZAMBON Walcott. [irxi'w, I divide; and afi^wu, a raised edge.] Schizamhon Walcott, 1884, Mon. U. S. Geol. Survey, vol. 8, pp. 69-70. (Described and discussed as a new genus.) Schizamhonia Oehlert, 1887, Manuel de conchyliologie, by Fischer, p. 1266. (Described in French.) Schizamhon Walcott, Hall and Clarke, 1892, Eleventh Ann. Kept. State Geologist New York for 1891, pp. 253-254. (Described and discussed.) Schizamhon Walcott, Hall and Clarke, 1892, Forty-fifth Ann. Rept. New York State Museum for 1891, pp. 569-570. (Copy of preceding reference.) Schizamhon Walcott, Hall and Clarke, 1892,. Nat. Hist. New York, Paleontology, vol. 8, pt. 1, pp. 113-117. (Copies the original description, Walcott, 1884b, p. 69, and discusses genus and species referred to it.) Schizamhon Walcott, Winchell and Schuchert, 1895, Nat. Hist. Minnesota, Geology, vol.3, pt. ,1, Paleontology, p. 360. (Copies the original description, Walcott, 1884b, p. 69, and discusses genus.) Schizamhon Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 4, PI. XI, and pp. 142 and 146. (Classification of genus.) Tills genus is described in Monograph VIII of the United States Geological Survey [Walcott, 1884b, p. 69] and very fully in Hall and Clarke's monograph [1892c, p. 113]. The type species is illustrated in this memoir on Plate LXXXIV. The other species now referred to the genus are S. ? esthonia Walcott, S. manitouensis Walcott, and S. priscus Matthew. As stated in the oi'igiiial description [Walcott, 1884b, p. 69] SipTionotreta fissa Kutorga appears to belong to the genus, and Hall and Clarke [1892b, pp. 115-116] include Schizmnbonf canadensis (Ami);" Messrs. Winchell and Schuchert [1895, pp. 361 and 362] ten- tatively include S.f dodgei and S.f lockei, and Mr. George H. Hudson [1904, p. 284] describes a new species, ScMzambon duplicimuratus, from the Chazy limestone on Valcour Island, Lake Champlain, New York. Type. — Schizamhon typicalis Walcott. SCHIZAMBON? ESTHONIA U. Sp. Plate LXXXIV, figure 4. This species is represented by a single specimen of the ventral valve. It is nearly circular in outline and moderately convex. Apex a little in advance of the posterior margin; a slight flattening back of the apex outlines a faint false area. A wedge-shaped depression extends from the sharp apex forward a short distance to its larger end where the large oval foramen occurs; this depression is similar to that in Schizambon typicalis Walcott and S. fissa (Kutorga) ; it is marked by fine lines of growth back of the foramen. Surface marked by fine concentric lines of growth and three narrow, low, concentric ridges or varices of growth; the entire surface is finely granulated, the granules being formed apparently by the crossing of fine, curving, oblique furrows that start on the posterolateral margin and curve forward obliquely across the shell, crossing so as to form rhomboidal spaces in which the granules occur. This type of surface is unlike the spinose surface of S. typicalis. It suggests the surface of Micromitra and some forms of Oholus (Westonia). From some points of view the crossing of the depressed lines gives a punctate appearance to the surface. It may be that this shell belongs to some other genus, but with the present information it is referred to ScMzamhon. The specific name is derived from Esthonia. Formation and locality. — Upper Cambrian: (336h) Ungulite grit, at Baltischport, Esthonia, Russia. a Siphonotrela scotica canadensis Ami, 1S87, Ottawa Naturalist, vol. 1, No. 9, p. 12'!. SIPHONOTRETID^. 623 SCHIZAMBON MANITOUENSIS n. sp. Plate LXXXIV, figures 3, 3a-e. General form and convexitj" much like those of ScMzambon typicalis Walcott, also surface characters if the influence of the different matrix is allowed for. The differences between the two species are in the larger foramen in S. manitouensis; in a shorter depression before the beak; in the interior markings of the dorsal valve and the strong area of the dorsal valve (PI. LXXXIV, fig. 3c). There may be a similar area in S. typicalis, but owing to the condition of preservation it has not been observed. The finely spinose surface is rarely seen, as it adheres to the matrix. The usual appearance of the shell is like that shown by figm-e 3. The average shell has a length of 4.5 mm., width about the same. Substance corneous. The specific name is derived from Manitou, Colorado. Formation and locality. — Lower Ordovician: (186 and 186a) " Near line of contact betzveen the red and gray Ordovician limestone, in siliceous red limestone about 30 feet (9.1 m.) above the pre-Cambrian rocks, Williams Canyon, Manitou; and (360) red siliceous limestone near Colorado Springs; both in El Paso County, Colorado. ScHizAMBON PRiscus Matthew. Plate LXXXIV, figures 2, 2a-e. ScMzambon prisons M.^tthew, 1901, Bull. Nat. Hist. Soc. New Brunswick, vol. 4, pt. 4, No. 19, pp. 277-278, PL V, figs. 4a-d. (Described and discussed as a new species. None of the specimens figured are reproduced in this monograph.) ScMzambon prisons Matthew, 1903, Geol. Survey Canada, Rept. Cambrian Rocks Cape Breton, pp. 187-189, PI. XI, figs. 6a-d. (Description and figiu-es copied from preceding reference.) Shell small and subcircular to transversely ovate, moderatelj' convex. Ventral valve sUghtly acuminate, with the apex above a short false area, and lower than the umbo. Foramen small, oval, and opening externally into an elongate groove tapering toward the beak; back of the foraminal opening a tapering ridge extends to the beak, leaving a narrower groove on each side. In the interior of the shell the edges of the tapering groove are slightly elevated and the foraminal opening appears to be of about the same size as the external opening. On some specimens of the ventral valve, on each side of the foramen on the outer sin-face, a narrow depres- sion extends forward and slightly outward nearly to the front margin ; this character corresponds to the low ridges in the ventral valve of Schizamhon typicalis Walcott (PI. LXXXIV, fig. la). The dorsal valve is less convex than the ventral, and its beak is marginal. The interior of the valve shows a median ridge of varying strength, and the same is true of the ridges indi- cating the narrow main vascular canals. In figure 2c the anterior portion of the median ridge is shown, also the oval, widely separated central muscle scars (h) and the small anterior lateral scars (j); in figure 2d the main vascular canals and the central portion of the median sinuses are shown. In figure 2e there is only a trace of vascular markings. Surface as preserved, marked by very fine radiating and concentric ridges that form on some shells a cancellated pattern; the fact that many shells adhere by the outer surface to the matrix leads me to suspect that the outer surface is roughened and probably spinose as in other species of the genus. ■ The average size of the shells is about 4 mm. in length and width. Shell substance corneous. Formation and locality. — Upper Cambrian: (lOf and lOg) Shales on the east branch of Barachois River, 0.76 mile (1.2 km.) north of the crossroad from Boisdale to Upper Leitches Creek; (lOh) at same locality as Locality lOf, but in shales of a slightly different horizon; (lOe) shales on the east branch of Barachois River, 0.5 mile (0.8 km.) north of the crossroad from Boisdale to Upper Leitches Creek; (101) shale on east bank of Barachois River, 6 miles (9.6 km.) from Little Bras d'Or Lake; (ISh) shale on the east bank of Barachois River, 1.5 miles (2.4 km.) north of Boisdale; (10k) shale on west bank of Barachois River, about 0.25 mile (0.4 km.) north of the Boisdale road; (lOd) shale on the west side of Barachois River, 0.125 mile (0.2 km.) north of the Boisdale road, opposite Mcllullin's place; (101) shale in high bank on the west side of Barachois River, just north of the Boisdale road; (307 [Matthew, 1903, p. 188J) shales of Division CSc of Matthew on McLeod Brook (=Barachois River); (3q) shale in Barachois Glen, 4 miles a 186a is tlie type locality. 624 CAMBRIAN BRACHIOPODA. (6.4 km.) south of Little Bras d'Or Lake; (3h) shale and shaly limestone on McNeil Brook, 1.5 miles (2.4 km.) east of Marion Bridge; and (372e [Matthew, 1903, p. 50]) shales on McMullins Brook, near McLeod Brook (=Barachoi8 River); all in eastern Cape Breton, Nova Scotia, Canada. (308 [Matthew, 1901a, p. 278]) Shales of Division C3c of Matthew at Navy Island, St. John Harbor, St. John Coimty, New Brunswick, Canada. Specimens somewhat doubtfully referred to this species occur at the following locality: Upper Cambrian: (10c) Shales in a horizon 50 feet below that of Locality 10k, on the west side of Barachoia River, eastern Cape Breton, Nova Scotia, Canada. SCHIZAMBON TYPICALIS Walcott. Plate LXXXIV, figures 1, la-d. ScMzambon typicalis Walcott, 1884, Mon. U. S. Geol. Survey, vol. 8, pp. 70-71, PL I, figs. 3, 3a-d. (Described and discussed as a new species. Figs. 3, 3a-d are copied in this monograph, PL LXXXIV, figs, la, 1, Ic, lb, and Id, respectively.) Schizambon typicalis Walcott, Hall and Clarke, 1892, Eleventh Ann. Rept. State Geologist New York for 1891, p. 253, PL IV, figs. 18-20. (Mentioned under genus Schizambon. Fig. 18 is copied from Walcott, 1884b, PL I, fig. 3a.) Schizambon typicalis Walcott, Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, pp. 114, 116, and 117; fig. 65, p. 114; and PL IV, figs. 27-30. (Mentioned in discussion of genus Schizambon. Fig. 65 is copied from Walcott, 1884b, PL I, fig. 3a. Figs. 27 and 29 are copied from figs. 19 and 20, respectively, of the preceding reference.) This species is fully described in Monograph VIII of the United States Geological Survey [Walcott, 1884b, pp. 70-71]. There is little to add to the description. For comparison with the other species the original figures are reproduced. Among the fossils occurring in limestone bowlders from Locahty 30w there is a single specimen of a ventral valve of a shell that appears to be identical with ScJiizamion typicalis. The points of identity are: (a) general form; (b) shape of foraminal opening; (c) fine, ele- vated, concentric striae. The only difference is the greater convexity, which is owing, I think, to the character of the matrix, the Nevada specimen being in a shaly limestone and somewhat compressed. Formation and locality. — lower Ordovlcian: (201a) Pogonip limestone, east slope of the ridge east of Hamburg Ridge, Eureka district [Hague, 1893, Atlas], Eureka County, Nevada. Upper Cambrian : (30w) Drift bowlder of limestone supposed to have come from la of the Notch Peak limestone on Notch Peak [Walcott, 1908f, p. 175], found about 2 miles (3.2 km.) south of Marjum Pass, House Range [Walcott, 1908f, PL XIII], Millard County; (33d) « thin-bedded blue limestone at the base of the first high point southwest of the J. J. Thomas ranch, on the east side of the Fish Spring Range, Juab County; and (54c) about 1,100 feet (335.3 m.) above the Middle Cambrian and 120 feet (36.6 m.) below the top of the Upper Cambrian in the central portion of the limestone forming 1 of the St. Charles formation [Walcott, 1908f, p. 192], in Blacksmith Fork Canyon, about 10 miles (16.1 km.) east of Hyrum, Cache County; all in Utah. Genus SIPHONOTBETA de Verneuil.!' [aitfiwv, a siphon or tube; t^jjtoj-, perforated.] Crania Eichwald (in part) [not Retzius], 1829, Zoologia specialis, vol. 1, p. 273. (Described in Latin. The genus includes species other than those belonging with Siphonotreta.) Terebratula Eichwald (in part) [not Lhwyd], 1840, Jour. Natur- und Heilkunde Medizinischen Akad. St. Petersburg, pts. 1 and 2, p. 138 (p. 24 in second part of one edition). (Merely places "Crania unguiculata and C. verrucosa" in this genus.) Terebratula Eichwald, 1842, Die Urwelt Russlands, Hft. 2, p. 145. (Merely mentions " Terebratula unguiculata.") Siphonotreta de Veeneuil, 1845, G^ologie de la Russie d'Europe, by Murchison, de Verneuil, and de Keyserling, vol. 2, pt. 3, p. 286. (Described in French as a new genus.) Siphonotreta de Verneuil, Kutorga (in part), 1848, Verhandl. Russ.-kais. min. Gesell. St. Petersburg for 1847, No. 12, pp. 261-263. (Described and discussed in German. Notes on the genus occur at various places on pp. 250-260.) Siphonotreta de Verneuil, Morris, 1849, Annals and Mag. Nat. Hist., 2d ser., vol. 4, pp. 315-320. (Notes on the genus and its generic relations.) a This species is somewhat doubtfully identified from this locality. b The synonymy for this genus is not complete; it includes only those references dealing with the species taken up in this monograph. SIPHONOTKETID^. 625 Siphonotreta de Verneuil, Morris, 1850, Rept. British Assoc. Adv. Sci. for 1849, Notices and Abstracts, pp. 57-58. (Notes on the genus.) Siphonotreta de Vemeuil, Davidson, 1853, British Fossil Brachiopoda, vol. 1, Introduction, No. 3, pp. 131-133. (Described and discussed.) Siphonotreta de Verneuil, Eichwald, 1860, Lethsea rossica, ancienne periode, vol. 1, sec. 2, p. 915. (Described in French.) Siphonotreta de Vemeuil, Seebach, 1865, Zeitschr. Deutsch. geol. Gesell. for 1865, Bd. 17, Heft. 2, p. 341. (Discussed in German.) Siphonotreta de Verneuil, Davidson, 1866, British Fossil Brachiopoda, vol. 3, pt. 7, No. 1, p. 75. (Mentioned.) Siphonotreta de Vemeuil, Quenstedt (in part), 1871, Petrefactenkunde Deutschlands, Abth. 1, Bd. 2, Brachiopoden, pp. 673-674. (Described and discussed in German.) Siphonotreta de Verneuil, Davidson, 1877, Geol. Mag., new ser., dec. 2, vol. 4, pp. 13-16. (Notes on the genus and its generic relations.) Siphonotreta de Vemeuil, Zittel, 1880, Handbuch der Pateontologie, Bd. 1, Abth. 1, pp. 665-666. (Described in German.) Siphonotreta de Verneuil, Davidson, 1883, British Fossil Brachiopoda, vol. 5, pt. 2, pp. 217-219. (Discussed.) Siphonotreta de Verneuil, Oehlert, 1887, Manuel de conchyliologie, by Fischer, p. 1265. (Described in French, with figures of S. unguiculata and S. verrucosa.) Siphonotreta de Verneuil, Hall and Clarke, 1892, Eleventh Ann. Rept. State Geologist New York for 1891, pp. 252-253. (Described.) Siphonotreta de Verneuil, Hall and Clarke, 1892, Forty-fifth Ann. Rept. New York State Museum for 1891, pp. 568-569. (Text copied from preceding reference.) Siphonotreta de Vemeuil, Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, pp. 110-113. (Described and discussed.) Siphonotreta de Verneuil, Winchell and Schuchert, 1895, Nat. Hist. Minnesota, Geology, vol. 3, pt. 1, Paleontology, p. 358. (Copies the description given by Hall and Clarke, 1892c, pp. 110-111.) Siphonotreta de Verneuil, Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 4, PL XI, and pp. 142 and 146. (Clas- sification of genus.) For the diagnosis of the genus, see Hall and Clarke [1892c, pp. 110-113]. The following notes are the result of the study of casts of a natural mold of the interior of the two valves united that I worked out from a specimen of S. unguiculata (PI. LXXXI, figs. 6, 6a-b) received from Dr. Fr. Schmidt, in which the transverse diameter is 18 mm. The cast of the interior of the ventral valve shows that the visceral area was elevated on a thickening of the shell, and that the muscle scars were attached in depressions in front of and beside the elevated visceral area; the main vascular canal was also on a ridge where it passed from the anterolateral edge of the visceral area. The points of attachment of the central, outside lateral, and middle lateral scars are not clearly defined as distinct scars in the specimens at hand, but the space occupied by them is very distiactly marked. It is very much like that of Oholus apoUinis Eichwald (PI. VII). The points of attachment of the transmedian and anterior lateral muscles are close to the elevated visceral area, just outside of the ridge beneath the maui vascular sinuses. The opening of the pedicle tube is not well preserved; this feature is illustrated by Davidson [1877, PI. II, figs. 8 and 9]. The interior of the dorsal valve shows a thickening of the shell in front of the antero- lateral muscle scars so as to form a transverse ridge that unites with the median ridge and a ridge on each side that appears to have been beneath the main vascular canals; within the subtriangular space thus formed the rather large anterolateral muscle scars occur as pits, and a little back of them, and of about the same size, the elongate oval central muscle scars; outside of the lateral ridge occur three large oval scars that correspond in position to the trans- median, outside lateral, and middle lateral scars of the dorsal valve of Oholus. The specimens studied by Davidson illustrate the interior of the ventral valve somewhat better than those before me, but the interior of the dorsal valve does not appear to have been so good. Type. — Crania unguiculata Eichwald. SiPHONOTEETA ? DtJBIA n. sp. Plate LXXXI, figures 7, 7a-b. Shell small, subcircular in outline. Ventral valve subcorneal, with the apex a short dis- tance in front of the posterior margin and directed backward ; it is truncated by a small, round 62667°— vol 51, pt 1—12 40 626 CM'IBEIAN BRACHIOPODA. opening that penetrates through the shell, but whether the opening is continued as a tube is unlaio\\Ti; a false area is slightly indicated on the slope between the pedicle aperture and the gently upward-arching posterior margin. Dorsal valve depressed in some examples so as to be slightly concave between the minute beak at the posterior margin and the front; in other examples it is flat and in some slightly convex. Surface of both valves marked by concentric lines of growth and low ridges from which spine bases extend across to the front edge of the next ridge, very much as in Si])honotreta unguindata (Eichwald) (PL LXXX) ; the spine bases are short and scattered on the posterior parts, numerous and elongated toward the front and lateral margins in the adult shells. The average diameter of the valves is from 3 to 4 mm. Substance of shell probably calcareocorneous; it is calcareous in the specimens, but this appears to have been the result of replacement of the original shell by impure calcite, which has also replaced the substance of associated trilobite tests. The generic reference is doubtful, as nothing is known of the interior of either valve. The circular pedicle opening distinguishes the species from ScJiizambon typicalis Walcott, which has a similar spinose surface (PI. LXXXIV, fig. Id), and relates it to SipJionotreta. I think that with full knowledge of this species it will be found to belong to an undefined genus, as it is not probable that SipJionotreta was developed so early in Cambrian time. This form owes its specific name to the doubtfulness of the generic reference. Formation and locality. — Lower Cambrian: (Iv) Shales of No. 3 of the Silver Peak group, Barrel Spring section fW^alcott, 1908f, p. 189], 3 miles (4.8 km.) north of Valcalda Spring and 4 miles (6.4 km.) west-northwest of the Drinkwater mine, Silver Peak quadrangle (U. S. Gaol. Sm-vey), Esmeralda County, Nevada. SiPHONOTRETA UNGUICtJLATA (Eichwald) . Plate I.XXXI, figures 6, 6a-e. Crania ungxdculata Eichwald, 1829, Zoologia specialis, vol. 1, p. 274, PL IV, fig. 3. (Described in Latin as a new species.) Crania sulcata Eichwald, 1829, idem, p. 274, PI. IV, fig. 4. (Described in Latin as a new species.) Terebratula unguiculata Eichwald, 1840, Jour. Natur- und Heilkunde Medizinischen Akad. St. Petersburg, pts. 1 and 2, pp. 138-140 (pp. 24-26 in second part of one edition). (Described in German.) Terebratula unguiculata Eichwald, 1842, Die ITrwelt Russlands, Hft. 2, p. 145, PL IV, figs. 2a-b. (Mentioned in German.) SipJionotreta unguiculata (Eichwald"), de Verneuil, 1845, G6ologie de la Russie d'Europe, by Murchison, de Verneuil, and de Keyserling, vol. 2, pt. 3, pp. 286-287, PL I, fig. 13. (Described in French.) Siphonotreta unguiculata (Eichwald), Kutorga, 1848, Verhandl. Russ.-kais. min. Gesell. St. Petersburg for 1847, No. 12, pp. 264 and 284, PL VI, figs, la-d, 2a-c, 3a-c. (Described in German on p. 264.) Siphonotreta unguiculata var. a Kutorga, 1848, idem, p. 284, PL VI, figs. 4a-e. (The description of this variety may be incorporated with that of the species on p. 264; it is only mentioned, however, in the description of PL VI, which is on p. 284.) Siphonotreta unguiculata var. P Kutorga, 1848, idem, pp. 264-265, PL VI, figs. 5a-d. (Characterized in German.) Siphonotreta unguiculata var. ;- elongata Kutorga, 1848, idem, p. 265, PL VI, figs. 6a-b. (Characterized in German as a new variety.) Siphonotreta unguiculata (Eichwald), D.ividson, 1853, British Fossil Brachiopoda, vol. 1, Introduction, No. 3, PI. IX, figs. 261-265, 269 and 270. (Mentioned on p. 133. Fig. 269 is copied from Kutorga, 1848, PL VI, fig. la.) Siphonotreta unguiculata Eichwald, 1860, Lethsea rossica, ancienne p6riode, vol. 1, sec. 2, pp. 915-916. (Described and discussed in French.) Siphonotreta unguiculata (Eichwald), Schmidt, 1861, Archiv fiir Naturkunde Liv-, Ehst-, und Kurlands, 1st ser.,Bd. 2, p. 218. (Localities mentioned.) Siphonotreta unguiculata (Eichwald), Quenstedt, 1871, Petrefactenkunde Deutschlands, Abth. 1, Bd. 2, Brachio- poden, p. 674, PL LXI, figs. 23-27. (Discussed.) Siphonotreta unguiculata (Eichwald), Davidson, 1877, Geol. Mag. new ser., dec. 2, vol. 4, footnote and figs. A and B, p. 14; p. 15, PL II, figs. 7-11. (Described and discussed. Fig. 9 is copied in this monograph, PL LXXXI, fig. 6c.) Siphonotreta unguiculata (Eichwald), Zittbl, 1880, Handbuch der Palseontologie, Bd. 1, Abth. 1, p. 666, figs. 489a-d. (No text reference. Figs. 489a-d are copied from Davidson, 1853, PL IX, figs. 265, 264, 262, and 261, respec- tively.) Siphonotreta unguiculata (Eichwald), Walcott, 1884, Mon. U. S. Geol. Survey, vol. 8, p. 16, PL I, fig. 8. (Discussed. Fig. 8 is copied from Davidson, 1877, PI. II, fig. 9.) SIPHONOTRETID^. 627 Siphonotreta unguiculata (Eicliwald), Quenstedt, 1885, Handbuch der Petrefactenkunde, Auflage 3, p. 755, PI. LVIII, fig. 53. (Discussed in German.) Siphonotreta unguiculata (Eichwald), Gagbl, 1890, Beitr. zur Naturkunde Preussens, von Physikal.-oekonom. Gesell. Konigsberg, 6, p. 23, PI. I, fig. 3. (Characterized in German.) Siphonotreta unguiculata (Eichwald), Hall and Clarke, 1892, Eleventh Ann. Kept. State Geologist New York for 1891, p. 253, PL IV, figs. 2^-26. (Mentioned. Figs. 22 and 23 are copied from Davidson, 1877, PL II, figs. 9 and 11, respectively. Figs. 24-26 are copied from Kutorga, 1848, PL VI, figs. 2c, 3b, and 3a, respectively.) Siphonotreta unguiculata (Eichwald), Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, p. Ill, PL IV, figs. 23-26. (Mentioned. Figs. 22-26 are copied from those in the preceding reference, which see.) The characters of this species are inchided in the generic description given by Messrs. Hall and Clarke [1892c, p. 110]. It differs from S. verrucosa (Eichwald) in its broader outline and more finely granulated and spinose surface. Figs. 6, 6a, and 6b are of a specimen received from Dr. Fr. Schmidt; fig. 6c is copied from Davidson [1877, PI. II, fig. 9]. Formation and locality." — Ordovician: (336g) Limestone in the vicinity of Zarskoe Selo; (336w) near Paw- lowsk; and (336x) in the Archangel quarry on the Volkhof (Wolchow); all near St. Petersbm-g, Russia. (336v) Echinosphxrites limestone at Reval; (337d) " Brandschief er " at Salla, near Erras, 85 miles (137 km.) east of Reval; and (337e) "Jewesche Schicht" at Altenhof, near Poddrus, 55 miles (88.6 km.) east of Reval; all in the Government of Esthonia, Russia. Drift bowlders of Echinosphxrites limestone at the following localities: (3861) Near Wehlau, 30 miles (48.3 km.) east of Konigsberg, East Prussia; (386j) at Belschwitz, East Prussia; (386k) near Wormditt, East Prussia; and (3861) near Marienwerder, West Prussia; all in Germany. Passage beds between the Upper Cambrian and the Ordovician: (336e) Orthoceratite limestone at Pulkowa; (337m) Orthoceratite limestone at Popowka; (337k) Orthoceratite limestone on the banks of Wolchow (Volkhof) River, near Lake Ladoga; and (336y) glauconitic limestone at Popowka; all near St. Petersburg, Russia. Orthoceratite limestone ("Vaginatenkalk") at the following localities: (336z) At Narwa; (337) at Erras, 85 miles (137 km.) east of Reval; (337a) at Kusal, 25 miles (40 km.) east of Reval; (337b) & at Reval; (337c) on Odensholm Island, 55 miles (88.6 km.) west of Reval; and (3371) ao Baltischport, west of Reval; all in the Government of Esthonia, Russia. Siphonotreta verrucosa (Eichwald). Plate LXXXI, figures 5, 5a-b. Terebratula veirucosa Eichwald, 1840, Jour. Natur- und Heilkunde Medizinischen Akad. St. Petersburg, pts. 1 and 2, pp. 140-141 (pp. 26-27 in second part of one edition). (Described in German.) Siphonotreta verrucosa (Eichwald), de Verneuil, 1845, Geologic de la Russie d'Europe, by Murchison, de Vemeuil, and de Keyserling, vol. 2, pt. 3, p. 287, PL I, figs. 14a-d. (Described in French.) Siphonotreta verrucosa (Eichwald), Kutorga, 1848, Verhandl. Russ.-kais. min. Gesell. St. Petersburg for 1847, No. 12, pp. 266-267, PL VII, fig. 1. (Described in German.) Siphonotreta verrucosa (Eichwald), Morris, 1849, Annals and Mag. Nat. Hist., 2d ser., vol. 4, PL VII, figs. 2a-d. (No text reference. Description of plate on p. 321.) Siphonotreta verrucosa (Eichwald), Davidson, 1853, British Fossil Brachiopoda, vol. 1, Introduction, No. 3, PL IX, figs. 267 and 268. (Mentioned on p. 133.) Siphonotreta verrucosa Eichwald, 1860, Lethtea rossica, ancienne p^riode, vol. 1, sec. 2, pp. 916-917. (Described and discussed in French.) Siphonotreta verrucosa (Eichwald), Schmidt, 1861, Archiv. fuf Naturkunde Liv-, Ehst-, und Km-lands, 1st ser., Bd. 2, p. 218. (Localities mentioned.) Siphonotreta verrucosa (Eichwald), Quenstedt, 1871, Petrefactenkunde Deutschlands, Abth. 1, Bd. 2, p. 674, PL LXI, figs. 28-30. (Discussed.) Siphonotreta verrucosa (Eichwald), Quenstedt, 1885, Handbuch der Petrefactenkunde, Auflage 3, p. 755, PL LVIII, figs. 52 and 54. (Discussed in German.) Siphonotreta veirucosa (Eichwald), Gagel, 1890, Beitr. zur Naturkunde Preussens, von Physikal-oekonom. Gesell. Konigsberg, 6, p. 22, PL I, figs. 2a-b. (Characterized in German.) This beautiful and instructive species is described by de Verneuil [1845, p. 287]. Figures 5, 5a, and 5b are drawn from a specimen received from Dr. Fr. Schmidt. The outer opening of the pedicle tube is a little longer than wide, and slightly pointed toward the minute beak, which is at its posterior margin. There is no trace of a groove or pseudodeltidium on the false area of this species or Siphonotreta unguiculata. " Localities 336y and 337m are represented in the United States National Museum collections; the other localities are taken from the references in the synonymy. The authority for each reference cited will be found in the list of localities, pp. 161-291. ''May be the type locality. Eichwald [1829, p. 274] gives it as " limestone at Reval." 628 CAMBRIAN BRACHIOPODA. FoHMATinN AND LOCALiTY.a — Ordovician : (336w) Near Pawlowsk, near St. Petersburg, Russia. Drift bowlders of Echinosphxrik's limestone at the follo\ving localities: (3861) Near Wehlau, 30 miles (48.3 km.) east of Konigsberg, East Prussia; (386k) near Wormditt, East Prussia; and (386 1) near Marienwerder, West Prussia; all in Germany. Passage beds between the Upper Cambrian and the Ordovician: (336e) Orthoceratite limestone at Pulkowa; (337m) Orthoceratite limestone at Popowka; and (336y) glauconitic limestone at Popowka; all near St. Petersburg, Russia. (337f) "Vaginatenkalk"6 atTiirsel, 15 miles (24.2 km.) west of Narwa; and (337g) " Vaginatenkalk " *> at Chudleigh, 25 miles (40 km.) west of Nai'wa; both in the Government of Esthonia, Russia. Genus KEYSERLINGIA Pander, c Orhicula de Verneuil (in part) [not Lamarck], 1845, Gilologie de la Russie d'Europe, by Mxu-chison, de Vemeuil, and de Keyserling, vol. 2, pt. 3, p. 288. (Described and discussed in French. Of the species included in the genus only "Orbiada buchii" is treated in this monograph.) Not Orbicella Dana, 1846; see Scudder's Nomenclator Zoologicus, p. 236. (Proposed for a genus of the Polypi.) Orbicella d'Orbigny (in part) [not Dana], 1850, Prodrome de Pal^ontologie, vol. 1, p. 20. (Characterized in French. "Orbicella buchi" is the only one of the many species placed under the genus which is treated in this monograph.) Keyserlingia Pander, 1861, Bull. Acad. imp. sci. St.-P6tersbourg, tome 3, columns 46^8. (Described and discussed in German.) Keyserlingia Pander, Daix, 1877, Bull. U. S. Nat. Mus. No. 8, p. 39. (Merely listed, but gives "Orbiaila reversa" as the type.) Orbicella d'Orbigny, Dall (in part), 1877, idem, p. 50. (Cites Orbicella buchi as the type and gives synonymy of genus.) Keyserlingia Pander, Oehlert, 1887, Manuel de conchy liologie, by Fischer, p. 1263. (Described in French, with figures of Keyserlingia buchi.) Not Keyserlingia Karpinsky, 1887, Bull. Acad. imp. sci. St.-P6tersbourg, tome 31, p. 476, footnote. (The use of the name Keyserlingia in this reference is clearly a typographical error, " Helmersenia" being the proper term.) Orbicella d'Orbigny, Hall and Clarke, 1892, Eleventh Ann. Rept. State Geologist New York for 1891, p. 254. (Pan- der's original description, 1861, p. 46, translated.) Orbicella d'Orbigny, Hall and Clarke, 1892, Forty-fifth Ann. Rept. New York State Museum for 1891, p. 570. (Copy of preceding reference.) Keyserlingia Pander, Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, pp. 117-119. (Copies the translation of Pander's original description given by Hall and Clarke, 1892a, p. 254, and discusses the genus and the priority of the generic names proposed for it.) Keyserlingia Pander, Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 4, PL XI, andpp. 142 and 146. (Classifica- tion of genus.) The description of the type species, Keyserlingia hucJii, gives all that is known of this genus. My description and remarks are based on the study of a considerable number of specimens collected for me by Mr. Schmalensee at Jaggowal, Esthonia, and a few received from Dr. Fr. Schmidt, collected at Kunitz, Government of Pskow. From the means of comparison with other related generic forms it appears that Keyser- lingia has an interior pedicle tube somewhat like that of Siplionotreta unguiculata (Eichwald), but that the pedicle cleft is back of the apex as in ScMzotreta elliptica Kutorga. A young shell has a very clear opening in the pedicle cleft, but in nearly all adult shells the opening is closed. In the interior of the ventral valve of many shells the pedicle tube extends forward into the valve (PI. LXXXI, fig. 4a) , but in adidt shells it is often closed by a vesicular growth of shell (fig. 4b). Keyserlingia, as exemplified by K. iucJii, is a form having an external pedicle cleft back of the apex much like that of ScMzotreta, and an interior pedicle tube extending forward a varying distance but not usually beyond the center. Type. — Orhicula hucM de Verneuil. The generic name was given in honor of A. de Keyserling. Keyserlingia buchi (de Verneuil). Plate LXXXI, figures 4, 4a-e. Orbicula buchii de Verneuil, 1845, G^ologie de la Russie d'Europe, by Murchison, de Verneuil, and de Keyserling, vol. 2, pt. 3, pp. 288-289, PL XIX, figs. la-c. (Described and discussed in French as a new species.) a Localities 336y and 337m are represented in the United States National Museum collections; the other localities are taken from the references in the synonj'my. The authority for each of the localities cited will be found in the list of localities, pp. 101-291. I have been unable to determine which i3 the type locality. 6 The Vaginoccras limestone is the equivalent of the CJrthoccrafilc limestone, c The s^nonomy for this genius is not complete; it includes only those references dealing with the species taken up in this monograph. SIPHONOTRETID^. 629 Orbicella buchi d'Oreigny (in part), 1850, Prodrome de Paleontologie, vol. 1, p. 20. (Changes generic reference, but includes "Orbicula reversa" also as a synonym of "Orbicella buchi.") Diseina buchii (de Verneuil), Eichwald (in part), 1860, Lethsea rossica, ancienne p&iode, vol. 1, sec. 2, p. 914. (Described and discussed in French. Eichwald includes Jeremejew's Siphonotreta ladogensis as a synonym.) Keyserlingia buchi (de Verneuil), Pander, 1861, Bull. Acad. imp. sci. St.-Petersbourg, tome 3, columns 46^8, PI. II, figs. la-h. (Described and discussed in German.) Orbicella buchi (de Verneuil), Hall and Clarke, 1892, Eleventh Ann. Kept. State Geologist New York for 1891, p. 254, PI. IV, fige. 8-10. (Mentioned as the type species. Figs. 8, 9, and 10 are copied from Pander, 1861, PI. II, figs, la, Ih, and Ic, respectively.) Keyserlingia buchi (de Verneuil), Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, p. 118, PI. IV, figs. 1-3. (Note fixing " K. buchi" as the type species. Figs. 1-3 are copied from Hall and Clarke, 1892a, PL IV, figs. 9, 10, and 8, respectively.) Shell inequivalve, circular, or slightly oval longitudinally or transversely. Ventral valve depressed conical with the apex from just in front of the posterior margin to one-fifth of the length of the valve toward the front margin; a rouglily outhned false area is formed by the incurving of the posterior slope from each side beneath the apex, to a narrow cleft that extends downward from the apex a varying distance toward the posterior margin; the narrow cleft is usually closed at the bottom, but in some examples it has a small elongate opening midway and in others a minute rounded opening toward the lower or posterior part. The exterior of the dorsal valve is slightly convex with the apex marginal. Surface marked by fine, concentric striae and a few stronger lines of growth that pass beneath the apex across the false area except where interrupted by the pedicle cleft ; when the latter is closed the strise do not cross the shell substance at the bottom of the cleft. In addition there are faint traces of fine radiating strise and on some ventral valves a few obscure, low, radiating ridges. The area of the ventral valve rises from the plane of the margins of the valve at an angle of about 45°; it is slightly arched inward at the center, and is marked by strong strise of growth parallel to the outer margin. Within the valve a median ridge of varying strength and length extends forward from the front margin of the area. In fifteen examples it is less than one-half the distance to the front margin, and in only one it extends forward beyond the center. On all unbroken specimens a strong projection extends upward from the median ridge just in advance of the area; it is narrow at the base, widening sideways and backward; it has a large variously shaped anterior opening that narrows toward the base of the projection; the size of the projec- tion and opening depends upon the amount of sheUy matter that has been deposited on and in it. The opening is the inner end of the pedicle tube; in some examples it is entirely filled %vith shelly deposit (PI. LXXXI, fig. 4b), and in others it is still open; in several examples with an open interior aperture the pedicle cleft is closed at the exterior end. The median ridge, in front of the pedicle tube, has a vesicular interior that gives it a hoUow appearance when the top is broken away. In several examples the pedicle muscle scar is clearly preserved, on the projec- tion fi'om the median ridge, just in front of the opening of the pedicle tube. On each side of the median ridge close to the area the cardinal muscle scars are either in a depressed pit or on a more or less elevated projecting growth of shell rising from the bottom of the valve; sometimes the projections extend beyond the plane of the margins of the valve (PI. LXXXI, fig. 4c), and often the central projection about tlie pedicle tube extends above the plane of the margin. On some shells the area indicated as the cardinal scar shows the points of attachment of three muscles, probably the umbonal, transmedian, and anterior laterals; the only indication of the points of attachment of the muscles corresponding to tlie central, outside, and middle laterals of Oholus is on the sides and beside the elevated pedicle tube. The area of the dorsal valve has a broad, triangular, slightly concave space at the center that is bounded by narrow flexure lines ; on each outer side of the flexure line the area narrows and slopes upward at an angle of about 30° to 45°; it is marked by distinct lines of growth that cross the central depressed space subparallel to the margin of the area. Within the valve a strong median septum extends from tlie area to tlie front part of the valve; this septum when broken shows an interior vesicular structure that gives the appearance of its having been hoUow. Well toward the front an oval muscle scar (central) occurs on each side of the septum; the car- dinal muscle scars are oval in outline close to the area and surrounded by a more or less tliickened 630 CAJVIBEIAN BRACHIOPODA. shell groMili in old shells. Between the large cardinal scars and tlie outer margin there is a narrow, elongate, depressed area in which the outside and middle lateral muscles may have been attached. Shell substance corneous. The shell is built up of numerous thin layers or lamellse, and the thick growth of the old shells is by irregular accretions. The average size of the shells is 5 to 7 mm. in diameter. Observations. — This interesting form was evidently in its younger stages a siphonate shell that had its pedicle tube closed by shell growth in the adult stage. I have broken several ventral valves on the line of the pedicle cleft and found that the shell within the cleft has a vesicular structure and that the opening could not be traced through the shell. The filling up of the pedicle tube and the deposition of shelly matter about the interior opening of the tube appear to have been a phase of adult growth and old age. The filling of the tube must have cut off the pedicle and left the shell to drift about very much as in the case of Leptsena rhomboidalis and BTiyncJiotrema capax [Hall and Clarke, 1894, p. 184]. This species differs from OrUcula reversa de VerneuU [1845, p. 289] in having the apex of the ventral valve much nearer the posterior margin. Formation AND LOCALITY. — Upper Cambrian : (395) OfcoZiis sandstone at Joa, near Jegelecht, 12 miles (19.3 km.) east of Reval, Government of Esthonia; (395b) Oholus sandstone at Ilgast, Government of Esthonia; (9d) Obolus sandstone at Jaggowal, about 20 miles (32.2 km.) east-southeast of Reval, Government of Esthonia; (336n [de VerneuU, 1845, p. 2S9]) on Ijora {Ischora) River, Government of St. Petersburg; (336o) Ungulite grit, Koporje, Government of St. Petersburg; (336a [Eichwald, 1860, p. 914]) Obolus sandstone at Podolova (Putalova?) on Ijora (Ischora) River, Government of St. Petersburg; and (336p) Ungulite grit, Kunitz, Government of Pskow; all in Russia. Superfamily ACROTEETACEA Schuchert. Family ACROTRETID^ Scliucliert. Subfamily ACROTHELIN^ Walcott and Scliucliert. Genus ACBOTHELE Linnarsson. « [&pof. at the top; and Stj^i!, nipple.] Acrothele Linnarsson, 1876, Bihang till K. svensk. Vet.-Akad. Handl., Bd. 3, No. 12, pp. 20-21. (Described and discussed in English as a new genus.) Acrothele Linnarsson, Zittel, 1880, Handbuch der Pateontologie, Bd. 1, Abth. 1, p. 665. (Described in German.) o The synonymy for this genus does not give a complete record ol the various genera under which the species now included in Armlkde were lormerly placed; it gives only those references in which the genus is discussed or described. To complete the record the followmg mere generic references are listed : JDiscina (Orbicula) de Vemeuil and Barrande L1860, p. 532). Oboldla Billings [lS62d, p. 68; 1863, p. 230]. Obolella Chapman |lSri3, p. 191; 1864, p. 163). Oboldla Salter [1866, p. 28.5]. Obolella Davidson [1868, p. 311]. Lingula Hartt [1868, p. 644). Obolella Davidson [1871, p. 341]. 0/)oJdiaFord[1873, p. 213]. Acroireta f White [1874, p. 6; 1877, p. 34]. Acrothele Brogger [1878, p. 76]. Lingula Hartt [1878, p. 644]. Acrolhele I.iimarsson [1879, p. 25]. Obolus 9 Barrande [1879b, PI. Oil: vn). AcTotnele White [1880, p. 41]. Biscina (Acrotreta?) Brogger [1882, p. 47]. Acrothele? Walcott [1884b, p. 14]. Acrothele Walcott [1884b, p. 15]. Billingsia Ford [1886a, p. 467]. Elkania Ford [1886b, p. 325]. Acrothele Matthew [1886, pp. .39 and 41]. Acroireta 'Walcott [1886b, pp. 107, 108, and 109]. Obolella f Walcott [1886b, p. HI]. Obolella Walcott [1886b, p. 118]. Acrothele Beecher [1891, PI. XVII, fig. 12]. Lingula Hartt [1891, p. 644]. Acrothele Walcott [lS91a, pp. 608 and 609]. Obolella Walcott [1891a, p. 612]. Obolella Hall and Clarke [lS92c, p. 70]. Acrotreta Hall and Clarke [lS92c, pp. 100 and 103]. Acrothele Moberg [1892b. p. 114]. Dixcina Miquel [1893, p. 9; 1894a, p. 106; 1894b, p. 10; 1895, p. 10]. Acrothele Matthew [1895a, p. 128, PI. V, figs. 7a-b, andPl. V.flgs. 8a-b]. Acrolhele Pompeckj [1896b, pp. 509-511 and 603]. Acrothele Matthew [1897, p. 168]. Linnars.ionia Schuchert [1897, p. 262]. Acrothele Walcott [1897b, p. 716; 1898b, p. 402]. Obolella Hobbs [1899, p. 114]. Acrothele Matthew [1899b, p. 202]. Acrothele Grabau [1900, p. 615). Linnarssonia 9 Walcott [1901, p. 673]. Acrothele Gronwall [1902, pp. 39 and 40]. Acrothele Matthew [1902b, pp. 396, 397, .398, 400, and 402; 1902c, p. 110]. Acrothele Walcott [1902, p. 598]. Obolella Delgado [1904, p. 364]. Acrothele Delgado [1904, p. 365). Acrothele f Walcott [1905a, p. 303). Acrothele Walcott [190.5b, p. 111. Acrothele Moberg and Segerberg[1906, p. 67). Acrolhele Shimer[1907, pp. 176 and 177). Obolella Grabau and Shimer [1907, p. 189). Acrothele Walcott [1908d, pp. 82-881. ACROTRETID^. 631 Acroihele Linnarsson, Davidson, 1883, British Fossil Brachiopoda, vol. 5, pt. 2, pp. 213-214. (Copies description given by Linnarsson, 1876, p. 20.) Acrothele Linnarsson, Walcott, 1886, Bull. U. S. Geol. Survey No. 30, pp. 107-108. (Copies original description [Linnarsson, 1876, p. 20] and discusses genus.) Acrothele Linnarsson, Oehlert, 1887, Manuel de conchyliologie, by Fischer, pp. 1269-1270. (Described in French.) Acrothele Linnarsson, Hall and Clarke, 1892, Eleventh Ann. Rept. State Geologist New York for 1891, pp. 249-250. (Described.) Acrothele Linnarsson, Hall and Clarke, 1892, Forty-fifth Ann. Rept. New York State Museum for 1891, pp. 565-566. (Copy of preceding reference.) Acrothele Linnarsson, Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, pp. 98-101. (Copies original description, Linnarsson, 1876, p. 20, and discusses genus.) Acrothele Linnarsson, Matthew, 1903, Geol. Survey Canada, Rept. Cambrian Rocks Cape Breton, pp. 103-105. (Dis- tribution discussed and tabulated.) Acrothele Linnarsson, Grabau and Shimer, 1907, North American Index Fossils, vol. 1, p. 200. (Described.) Linnarssonia Grabau and Shimer?, 1907, idem, p. 200. (Described, but the only species referred to the genus (Lin- narssonia pretiosa) is not figured, and it is impossible to tell whether the authors are discussing the L. pretioaa that is now referred to the genus Acrotreta {Acrotreta sagittalis), or to the genus Aa-othele {Acrothele pretiosa).) Acrothele Linnarsson, Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 4, PI. XI, and pp. 142 and 146. (Classi- fication of genus.) General form subcircular to transversely broad oval in outline. Ventral valve moderately convex to subconical; a false area is usually more or less distinctly outlined on the ventral valve between the apex (beak) and the posterior margin; pedicle opening on the posterior slope of the apex (or beneath the beak). The only suggestion of a true cardinal area is in Acroihele heUula Walcott (PI. LVIII, fig. 5c); and this appears to be a broadening and slight flattening of the posterior under edge of the shell. Dorsal valve gently convex, and some- times nearly flat; beak minute, marginal; area known only in A. heUula Walcott (PI. LVIII, figs. 5f-h), where it is short and divided midway by a small, triangular false deltidium, very much as in Acrotreta definita Walcott (PI. LXIV, fig. 2d.) Surface marked by concentric lines and stride of growth which cross the false area of the ventral valve; on some species there are low, rounded, radiating ridges that are usually con- fined to the ventral valve; in addition,- on some species, there is a series of more or less inoscu- lating, irregular, fine ridges with tubercles on them, which gives a highly ornamented surface such as occurs on some forms of Micromitra and Westonia. The shells of Acrothele rarely exceed 13 mm. in diameter, and the average size of adult sheUs is from 6 to 8 mm. Substance of shell corneous. The shell is built up of several layers or lamellae that are usually more or less obliquely inchned to the outer surface, over the central and outer portions. The interior of the ventral valve has a small visceral area about the pedicle opening and extending a short distance in front of it; in several species an elongate depression occurs on each side and a little in advance of the pedicle opening that corresponds to the tubercle on each side of the apex of the outer surface ; frequently the shell is thickened beneath the visceral cavity and a short ridge of varying width and length results; the edge of the pedicle opening may be slightly thickened, which forms a callosity or apical swelling, but not to the same extent as in the ventral valve of Acrotreta. Nothing has been seen of an area in front of the visceral area corresponding to the trapezoidal areas of Oholus, Aa^otreta, and Trematoiolus, in which the central, outside lateral, and middle lateral muscles were attached ; in fact, it is only very rarely that the impression of the visceral area is shown. The main vascular sinuses start from just back of the pedicle opening, and curve, one on each side, out and then forward into the body of the valve, usually within a line drawn halfway between the center and the outer margin of the valve; many branches from the main sinus occur in some species. The trans- median and anterior lateral muscle scars appear to be merged in the cardinal muscle scar, situ- ated on the outer posterolateral slope, outside of the main vascular sinuses; on one shell what appear to be the umbonal muscle scars are preserved (PI. LXI, fig. Ic). The interior of the dorsal valve has a median ridge of varying length and size, and main vascular sinuses that start near the posterior margin and extend directly outward for a short distance, and then obliquely forward in almost a direct line (PI. LVI, figs. Id and le; PI. LX, figs. Ik and 1 1). The cardinal muscle scars are usually small and close to the posterolateral 632 CAilBRIAN BRACHIOPODA. margin (PI. LX, fig. Ik), but larger scars occur and extend farther forward into the valve (PI. LXII, fig. If; PI. LVIII, figs. 3c, 3d, and 5h). The central and anterior lateral scars are situated essentially as in Oholus; the former on the slopes of the median ridge and the latter at the anterior end of the ridge. Type. — Acroihele coriacea Linnarsson. Observations. — The generic description is drawn up from the material studied in connec- tion with the various species now referred to the genus. One of Linnarsson's species, Acroihele granulata [1876, p. 24] I have taken as the type of the subgenus Redlichella on account of the difl'erences in the interiors of the valves. Surface characters. — The surface characters of the various species of Acroihele vary nearly as much as those of Micromitra. The species may be grouped by the surface features under three headings: (1) Striato-granulose ; (2) concentrically ridged, striated, or nearly smooth; (3) pseudopunctate. The first group, striato-granulose or radulo-granulose, includes, as now known, sixteen species and seven varieties. The surface of the type species of the genus, Acrothele coriacea Linnarsson, is representative of this form of surface. It has concentric lines of growth, and a series of concentric, irregular, more or less inosculating, rounded, fine ridges upon which minute nodes or granules occur; these granules, on some species, are more or less regularly arranged on the ridges and appear over nearly the entire surface (PI. LVI, fig. Ig), while in others they are scattered irregularly (PI. LXI, fig. 4d). On Acrothele matthewi (Hartt) (PI. LXI) and some other species the younger shells are granulated, while on the older shells the ridges are fairly regular and only an occasional granule occurs on them. On most adult shells with this form of surface the ridges near the margin are more regular and rarely inosculate. This type of surface occurs also on Acrothele {Redlichella) granulata (Linnarsson) (PL LVIj fig. 2g) and Botsfordia granulata (Redlich) (PI. LVII, fig. 4r) and Botsfordia cselata (Hall) (PI. LIX, figs. Ih and lo). The species upon which I have seen the ridges and granules are: Acrothele avia Matthew. avia puteis Matthew, bergeroni Walcott. coUeni Walcott. coriacea Linnarsson. decipiens Walcott. gamagei (Hobbs). intermedia Linnarsson. matthewi (Hartt). matthewi eryx Walcott. matthewi lata Matthew, matthewi multicostata Matthew. Acrothele panderi Walcott. pretiosa (Billings), prima (Matthew), prima costata (Matthew), proles Matthew, quadrilineata Pompeckj. spurri Walcott. subsidua (White), subsidua hera Walcott. subsidua Isevis Walcott. yorkensis Walcott. Acrothele hellula Walcott has this type, of surface, but the ridges and granules are so minute that they are only to be seen with a very strong lens. The second group is concentrically ridged, striated, or smooth, as far as known. I think, however, that %vith better-preserved specimens some of the species now included under it would be found to have the striato-granulose surface. The species referred to it are : Acrothele bohemica (Barrande). borgholmensis Walcott. ceratopygarum (Brogger). levisensis Walcott. maculata (Salter). On the pseudopunctate surface the union of the inosculating ridges is very regular and the hollows or pits between the ridges are arranged in oblique lines that appear to start on the posterolateral margins of the valves and curve obliquely forward to the opposite Acrothele? minuta Walcott. Acrothele nitida (Ford). tmrneri Walcott. woodworthi Walcott. ACROTRETIDiE. 633 side (PL LVII, fig. 3b). It is the same type of surface as that of Botsfordia pulchra (Matthew) (PI. LXII, figs. 5, 5a-c) and Micromitra (Iphidella) pannula (White) (PL IV, figs. It arid Is). Tlus form of surface is represented by only one species: Acrothele hellapunctata Walcott (PL LVII, figs. 3, 3a-b). The surface of the follo\ving species has not been definitely determined owing to the condi- tion of preservation. I think most of them wTill be found to belong to the group represented by A. coriacea Linnarsson (p. 642) : Acrothele dichotoma Walcott. pr-mseva (de Verneuil and Barrande). rara Walcott. villaboimensis Delgado. sp. undt. a Walcott. sp. undt. Moberg. The group of forms described by G. F. Matthew [1903, pp. 9S-103] from the "Etcheminian" of Nova Scotia, and A. prima (Matthew) [1SS6, p. 41] from New Bruns^^^ck, and A. prima costata (Matthew) [1895a, p. 128], are all closely related by their general form, usualty strong shells, and surface characters; the latter are variable but the range of variation is usually to be found on anjr large, old shell, an exception being found in radiating ridges, which varj^ greatly and to a certain extent depend upon conditions that affected the shell after the animal died, such as maceration and distortion by compression and movement ia the embeddmg sediment. The shells above the horizon of the Paradoxides zone, represented by Acrothele matthewi (Hartt), appear to have been affected also by the same conditions, although the sediment is usually finer and more compact. Pompeckj [1896b, p. 603] thought that the shell described hj de Verneuil and Barrande [1860, pp. 536-537] was probably a species of Acrothele, and probably the same as the shell collected by ]\Iiciuel. Mj^ study of jVIiquel's material shows that a true Acrothele is repre- sented: A. hergeroni Walcott (PL LVIII, figs. 6, 6a-c). The other form is biconve.x, calcareous, and not a tj^pical Acrothele. I have referred to it provisionally (p. 602) us Botsfordia f harrandei. Comparisons with other genera. — The relations between Acrothele and Acrotreta were recog- nized by Linnarsson [1876, p. 20] and by all subsequent authors who have had occasion to discuss the genus. Both genera have (a) a more or less elevated ventral valve with a pedicle opening at the summit of a more or less distinctly defined false area; (b) a moderately convex dorsal valve with somewhat similar interior markings; (c) small visceral areas in the ventral valve; (d) corneous shells built up of thin layers. . Acrothele differs from Acrotreta (a) in having a depressed ventral valve; (b) a faintly defined false area in the ventral valve; (c) larger size; (d) greater variety and more liighly ornamented surface; (e) apparently more complex vascular markings; and (f) a difference in the position of the main vascular sinuses ; for the dorsal valve this is best seen bj" comparing Plate LX, figures Ik and 1 1, Acrothele subsidua (White), with Plate LXV, figures If and Ig. I have examined many hundred specimens of the interior of dorsal valves of Acrotreta without fuiding any traces of the main vascular sinus, whereas in Acrothele they are usually present. In the ventral valve the differences are also marked, as the vascular sinuses are proportionally much larger ia Acrotreta. There are exceptions to the marked difference in elevation of the ventral valve, as that of Acrothele suhsidua {White) (PL LX, figs, la, Ic, and Id) is nearly as elevated as that of Acrotreta sagittalis taconica (Walcott) (PL LXXI, figs. 1, la-e). Acrotreta appears to be a somewhat more highl}^ delevoped form than Acrothele, although a smaller shell. Geographic distribution. — Species of the Acrothele coriacea type occur in Sweden, Denmark, Bohemia, southern France, and Portugal in Europe; in eastern North America, in Nova Scotia and New Brunswick; in western North America in Utah, Nevada, Idaho, and Montana. Tliis indicates the wide distribution of one specific type, and other forms extend the distribution 634 CAJ\IBRIAN BRACHIOPODA. far to the south in the Appalachian province, ^4. hellula Walcott; and to the north in Pennsyl- vania, A. yorhensis Walcott. The general distribution of species is given in the table (p. 105) and the details of each species under the specific description. Stratigraphic range. — Acroihele is represented by eight species and one variety in the upper portion of the Lower Cambrian in association with Olenellus or allied forms of trilobites, but in no instance has it been found low down in the Lower Cambrian. In the Middle Cambrian twenty-one species and six varieties occur, and there the genus attained its widest distribution and greatest development. One species, A. iorgholmensis Walcott, occurs in strata of the Geratopyge zone, and three species in Lower Ordovician formations. Of the latter, A. ceratopy- garum is not a typical form of Acroihele. (See p. 640.) ACROTHELE ARTEMIS Walcott. Text figiire 54. Acrothele artemis Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, p. 82, PL VIII, fig. 10. (Described and discussed as below as a new species. Fig. 10 is copied in this monograph as fig. 54.) General form of ventral valve moderately convex; subcircular and somewhat obtusely acuminate in outline; apex near the posterior margin; pedicle opening unknown, but from the occurrence of a small boss on the inside of the shell beneath the apex it was probably of the same character as in closely related species. Surface marked by concentric lines and small ridges of growth, and an irregular system of fine granules on the concentric ridges; in the lower interspaces there is an irregular distribution of very minute inosculating ridges that, with the tubercles, form a surface independent of the concentric growth lines. The shell is built up Figure o4.-^crotte/£arte77)!s Walcott. of numcrous lamella3 beneath the outer surface layer and appears A, A', Ventral valve with the apex , , ^p^^, pti broken. The specimen is irom Lo- to have been comsous, or composcd 01 phospliate or nme and cality 5b, Middle Cambrian lime- chitin east ot Maiade, Oneida County, The largest shcll has a length and width of 10 mm.; the apex Idaho, (u. s. Nat. Mus. Cat. No. jg about 2 mm. from the posterior margin ; dorsal valve unknown. 51969.) The figure is copied from „, ,. _, . ^ . i i • f a jt i Walcott, i908d, PI. vm, flg. 10. Observations. — 1ms species resembles m iorm Acrotfiele prima costata (Matthew) (PI. LXI, figs. 4 and 4a), and both species have a granular surface. The latter species, however, has a thinner shell, and its surface is marked by much larger granules. I know of no other closely related species. Formation and locality. — Middle Cambrian: (5b) Dark blue-gray Langston limestone [Walcott, 1908f, p. 198], just above the Cambrian quartzitic sandstones, north side of Twomile Canyon, near its mouth, 2 miles (3.2 km.) south- east of Maiade, Oneida County, Idaho. Acrothele avia Matthew. Plate LXI, figures 7, 7a-b; Plate LXII, figures 1, la-k. Acrothele avia Matthew, 1899, Bull. Nat. Hist. Soc. New Brunswick, vol. 4, pt. 3, No. 18, pp. 202-203, PL III, figs, la-h. (Described as a new species. The specimens represented by figs. Ic and If are redrawn in this mono- graph, PL LXI, figs. 7a and 7b, respectively.) Acrothele avia Matthew, 1902, idem, pt. 5, No. 20, pp. 396-398, PL XVI, figs. 7a-b; PL XVII, figs, la-f and 2a-b. (Described and discussed. PL XVII, figs.' la-f, and PL XVI, figs. 7a-b, are copied from Matthew, 1899b, PL III, figs. la-h. The specimens represented by figs. 2a and 2b are redrawn in this monograph, PL LXI, fig. 7, and PL LXII, fig. li, respectively.) Acrothele abavia Matthew, 1902, idem, pp. 398-400, PL XVI, figs. 3a-d and 4a-b. (Described and discussed as a new species.) Acrothele avia Matthew, 1903, Geol. Survey Canada, Rept. Cambrian Rocks Cape Breton, p. 55. (Notes on orienta- tion of valves.) ACROTRETID.E. 635 Acrothele mm Matthew, 1903, Geol. Survey Canada, Eept. Cambrian Rocks Cape Breton, pp. 98-99, PL V, figs. la-f and 2a-b. (Described and discussed essentially as in Matthew, 1902a, pp. 396-398. Figs, la-f are copied from Matthew, 1899b, PI. Ill, figs, la-f; figs. 2a and 2b are copied from Matthew, 1902a, PI. XVII, figs. 2a and 2b, respectively.) Acrothele abavia Matthew, 1903, idem, pp. 100-101, PI. IV, figs. 3a-d and 4a-b. (Described and discussed as in Matthew, 1902a, pp. 398-400. Pigs. 3a-d and 4a-b are copied from Matthew, 1902a, PI. XVI, figs. 3a-d and 4a-b, respectively.) This is a strong shell of the Acrothele matthewi (Hartt) type. The adult shells are some- what thicker, the surface is a Httle different, being coarser, and the callosity in front of the pedicle opening is longer and larger than in A. matthewi or its varieties. Matthew [1902a, p. 396] gives as one of the most marked distinctions of this species the presence on the sides of the dorsal valve of "about a dozen radiating, brandling, crenulated ridges that extend to the margin." With all of Matthew's types before me, I find one bit of rock mth two ventral valves, one partly overlapping the other; on these the radiating ridges not only occur on the sides, but also over the middle of the shell, and where a bit of the shell is broken off the ridges are clearly impressed on the cast of the interior; this specimen is labeled as one of the original types of the species ; a second ventral valve preserving a part of the exterior surface also shows traces of radiating ridges. Another type specimen shows part of the exterior surface and the cast of the interior, but there is no trace of a radiating ridge on the outer surface or cast ; seven specimens of the dorsal valve on which the outer layer is exfohated show no traces of the radiating ridges. I find further that the dorsal valves on which the radiating ridges occur are very thin and hence liable to be flexed by lateral pressure, developing surface ridges on the hues of radiating strise that occur on the inner layers of nearly all shells of Acrothele. On the ventral valve a few radiating ridges occur on one of the specimens (PI. LXIJ fig. 7) ; another specimen, laterally compressed, shows many such ridges (PI. LXI, fig. 7a). Other specimens are without exterior traces of ridges, but when the shell is exfoliated, numerous fine, radiating striae with stronger and deeper strife at wider intervals are to be seen. I have taken up this matter of the radiating ridges at length, as I do not consider the side ridges on the dorsal valve of Acrothele avia sufficient to separate it from other species to which it is closely related. The surface is formed of fine, irregular, concentric, rounded ridges that frequently inoscu- late ; these ridges are crenulated by fine depressions which cross them and thus outHne tubercles or rounded points of varying height and size, depending upon the depth of the radiating cross depressions; this type of surface gives great variety to different parts of the shell and to dif- ferent shells. As far as I can determine by the use of a strong lens (three-quarter inch) it is essentially the same type of surface as that occurring on Acrothele matthewi (Hartt) and related species, one of which is shown by Plate LXI, figure 4d. At the apex of one of the specimens of the ventral valve in Matthew's collection there are two minute elongate tubercles with a narrow depression between them, and on the pos- terior slope there is an oval pedicle opening with the narrow end nearest the apex; a low, narrow ridge, that divides the obscure false area midway, extends from the opening to the posterior margin. "Acrothele abavia" Matthew does not appear to vary specifically from the forms of Acrothele avia in which the radiating ridges are absent. The specimens occur in a little coarser sediment, and on this account are not well preserved. Matthew [1902a, p. 399] speaks of a small tubercle in front of the pedicle opening and "the visceral callus that extends half of the length of the shell " of the ventral valve ; such a tubercle occurs on the only two specimens of A. avia well enough preserved to show the interior of the ventral valve. I do not find the elongate visceral callus on any specimens of the ventral valve in Matthew's collection; some specimens do show a short callosity similar to that in A. avia. After a very careful study of all the specimens, also of a large collection from the same locality and strata belonging to the United States National Museum, I am led to think that Matthew mistook the median ridge of some dorsal valve in which the posterior portion was broken away as the visceral callosity of the interior of a ventral valve; this behef is further strengthened by his statement [1902a, p. 399]: "On each side of the callus a groove runs out toward the front margin. Some 636 CMIBRIAN BRACHIOPODA. examples show a median and two lateral septa in front of the callus.' (See interior of dorsal valve as shown by PI. LXII, fig. Ig.) In the United States National Museum collection, from Matthew's horizon E3a, I find 13 interiors of the ventral valve with short "callus" and 10 typical exteriors, also 22 dorsal valves. There are also fair specimens from horizons 3d and 3e. The shells of horizon^a have the oblate form of Acrothele avia found at horizons 3d and Be. Acrothele avia differs from Acrothele proles Matthew in having the apex of the ventral valve a little nearer the posterior margin, but not so near as that of Acrothele prima (Matthew). Formation and locauty. — Middle Cambrian: (13d'') Sandstones 10 feet (3 m.) below Division E2a; (13d and 13d') sandstones opposite the third waterfall in Dugald Brook, between Divisions E2a and B2b; (lOp) sandstone just below the waterfall in Division E2b; (131 and 131') sandstones of Division E3a; (344 [Matthew, 1903, p. 81]) Bandy- shales of Division E3b; (344a [Matthew, 1903, p. 26]) sandy shales of Division E3c; (344b [Matthew, 1903, p. 81]) sandy shales of Division B3d; (13n')o sandstones of Division ESe; and (13n) sandstones of Division E3f; all in Mat- thew's [1903, p. 21] Etcheminian, on Dugald Brook, Indian River, eastern Cape Breton, Nova Scotia. (13m) Sandstones of Division E3f of Matthew's [1903, p. 76] Etcheminian, on Gillis Brook, Indian River; and (lOp") sandstone on the small brook on the hill between the bridge over Indian River and McPhees Brook; both in eastern Cape Breton, Nova Scotia. Acrothele avia puteis Matthew. Acrothele avia-puteis Matthew, 1902, Bull. Nat. Hist. Soc. New Brunswick, vol. 4, pt. 5, No. 20, p. 398, PL XVI, figs. 5a-b. (Characterized as a new variety.) Acrothele avia-puteis Matthew, 1903, Geol. Survey Canada, Rept. Cambrian Rocks Cape Breton, p. 100, PI. IV, figs. 5a-b. (Characterization and figures copied from preceding reference.) This seems to be a variety of Acrothele avia Matthew. It differs in the possession of a pair of pits, one of wliich lies on each side of the space between the foramen and the visceral callus, partly overlapping each. The visceral callus is quite short in this form and has but little promi- nence. The ridges on the surface of the shell are more regularly concentric than in the type, and more sharply cut; about ten are found in the space of 1 millimeter. The cardinal area is curved forward toward the top, and finely striated. The foramen is about a fifth of the length of the valve from the cardinal line, and the front of the callus about a third. Vascular trunks and branches are visible on the surface of the ventral valve as in A. avia. The dorsal valve does not sensibly differ from that of A. avia. The largest valve seen was 8 mm. long and about the same width. The typical specimens of the ventral valve oi Acrothele avia puteis are slightly different from those of Acrothele avia, but not sufficiently so to show clearly in an illustration. The pits beside the median line, between the pedicle aperture and the visceral callosity, do not appear in the specimens of the species, and indeed the condition of the material is such that probably they could not be distinguished if originally present. The visceral callosity is shorter and much like that of Acrothele matthewi (Hartt). Formation and locality. — Middle Cambrian: (13m) Sandstones of Division E3f of Matthew's [1903, p. 76] Etcheminian, on Gillis Brook; and (344c [Matthew, 1903, p. 100]) sandy shales of , Division ESd of Matthew's Etche- minian, on Gregwa Brook; both in the Indian River valley, eastern Cape Breton, Nova Scotia. Acrothele bellaptjnctata Walcott. Plate LVII, figures 3, 3a-b. Acrothele bellapunctata Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, pp. 82-83, PL VIII, figs. 9 and 9'. (Described and discussed as below as a new species. Figs. 9 and 9' are copied in this monograph, PL LVII, figs. 3 and 3b, respectively.) General form a broad transverse oval with the posterior side slightly flattened and arched upward for a short distance below the apex. Ventral valve convex near the umbo and nearly flat over the anterior portion of the valve; apex near the posterior margin. Foraminal aper- ture apparently at the apex above a short, not distinctly marked, false area. Ventral valve nearly flat and with the posterior margin curved downward so as to fill the space caused by a 13a' is the type locality, though the specimens in the United States National Museum collections to which that number is assigned were collected later than the type specimens. ACEOTRETID^. 637 the upward arching of the margin of the ventral valve. Surface of shell beautifully ornamented by elevated sharp oblique lines with deep interspaces that give a strongly punctate appear- ance to the shell; concentric undulations and ridges of growth also occur in a more or less irregular manner. The inner layers or lamellae are marked by fine, concentric, and rather strong radiating lines. The shell is built up of numerous thin layers or lamellae of a corneous appearance. A slightly compressed ventral valve has a length of 5 mm. with a width of 6.5 mm. A ventral valve is 4 mm. in length with a width of 5 mm. Observations. — This is one of the most beautifully ornamented species of the genus. Its surface is not unlike that of some varieties of Micromitra (IpJiidella) pannula (White). In form it suggests AcrotJiele (Redlichella) granulata (Linnarsson). Nothing is known of the interior character of the valves. Formation and locality. — lower Cambrian : (8v) Shales in upper portion of Holmia hjerulfi zone, Ringsaker; Province of Hedemarken, Norway. ACROTHELE BELLXILA Walcott. Plate LVIII, figures 5, 5a-h. Acrothele hellula Walcott, 1897, Proc. U. S. Nat. Mus., \ol. 19, pp. 716-717, PI. LX, figs. 4, 4a-e. (Described and discussed as a new species. Figs. 4, 4a-e are reproduced (with slight changes) in this monograph, PI. LVIII, figs. 5, 5a, 5c, 5f-h, respectively.) General form transversely broad oval, with the posterior margin slightly transverse. Ventral valve slightly conical with the apex between the posterior seventh and eighth of the length of the valve; the slope from the apex to the posterior margin is about 45° and to the front at a low angle after passing from the steeper slope adjoining the apex. On each side of the apex there is an elongate, sharp tubercle, and just back, a minute pedicle opening. A slightly outlined triangular false area begins at the pedicle opening and extends to the posterior margin; it is divided by a faint, narrow, rounded ridge. Dorsal valve moderately convex, with the umbo broad, and beak at the posterior margin. The exterior surface is marked by concentric lines of growth that cross the area of the ventral valve. The ventral valve has numerous low, narrow, obscure radiating ridges, and an extremely minute series of irregular, concentric, inosculating elevated lines that give the surface a roughened appearance under a strong lens. Substance of the shell in appearance corneous. The largest shell in the collection is repre- sented by a dorsal valve; this has a length of 6 mm.; width, 7 mm. The casts of the interior of the ventral valve are very good; they show that the shell was thick over the umbo, that the cast of the pedicle opening was eone-shaped (PI. LVIII, fig. 5b), and that on each side just in front of the base of the opening there was a short, narrow depression corresponding in position to the tubercles on the outer surface. Back of the cast of the opening the false area is rather strongly defined, also the cast of the hollows occupied by the cardinal muscles; the main vascular sinuses originate just back of the pedicle opening and arch forward toward the anterolateral margins of the shell (PI. LVIII, fig. 5e) ; usually they have left no impression on the shell in advance of the visceral area; the visceral area is short and fairly well defined on some specimens (fig. 5d). Notlxing is known of the muscle scars of the ventral valve except the position of the cardinal scars. The cast of the interior of the dorsal valve is most interesting, as a true area similar to that of Acrotreta definita Walcott (PI. LXIV, fig. 2d) and Acrotreta Icutorgai Walcott (PI. LXV, fig. 3j) is clearly shown; the area is short and divided midway by a triangular space, the lateral, slightly elevated sides of which project a little into the valve beyond the front margin, very much as in Oholella atlantica Walcott (PL LV, fig. le) and 0. crassa (HaU) (PI. LTV, fig. 2g). A median ridge extends from in front of the area to the anterior third of the valve; it has a narrow, low, median septum on its posterior half, and two central muscle scars (h) on its outer slopes a Httle back of the center of the valve; the anterior lateral muscle scars (j) are a little in 638 CAMBKIAN BRACHIOPODA. advance of the centrals, close to the median ridge and smaller than the centrals; the main vascular sinuses are very faint beA'ond where they come forward into the body of the valve; back toward the posterolateral margin of the valve small cardinal scars occur at about the same distance from the center of the area as the central scars are in front of it. Ohservations. — This species is so strongly marked in its ventral valve by the pointed tuber- cles beside the apex, the cone-shaped pedicle passage through the shell, and distinct visceral area, and in the dorsal valve by a well-defined area and small cardinal muscle scars far out on the cardinal slope, that it can not readily be confused with any known species. Formation and locality. — Middle Cambrian: (94x) Shales 0.06 mile (0.1 km.) south of Givens Mill, Cowan Creek, about 8 miles (12.8 km.) southeast of Center; and (90x) in and attached to the outer surface of siliceous nodules in the Conasauga ("Coosa") shale, Coosa Valley, east of Center; both in Cherokee County, Alabama. ACKOTHELE BERGEEONI Walcott. Plate LVIII, figures 6, 6a-c. La Discina Miquel, 1893, Note sur la G^ologie des Terrains PrLmaires du D4partement de I'H^rault, St. Chinian h. Coulouma, p. 9. (Mentioned in French.) La Discina Miqitel, 1894, Bull. Soc. d'Etude Sci. Nat. B6ziers for 1893, M^m. Compt. Rend, des Seances, vol. 16, 1894, p. 106. (This article is a copy of the preceding reference which was published as a separate.) La Discina Mkjuel, 1894, Note sur la Geologie des Terrains Primaires du D^partement de l'H6rault, le Cambrien et I'Arenig, p. 10. (Mentioned in French.) La Discina Miquel, 1895, Bull. Soc. d'Etude Sci. Nat. B&iers for 1894, M6m. Compt. Rend, des Seances, vol. 17, 1895, p. 10. (This article is a copy of the preceding reference which was published as a separate.) Acrothele Pompeckj (in part), 1896, Jahrb. K.-k. geol. Reichsanstalt for 1895, Bd. 45, Hft. 8, p. 603. (Discussed in German, changing generic reference; see under Botsfordia ? harrandei, p. 603, for copy.) Acrothele bergeroni Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, pp. 83-84, PL VIII, fig. 11. (Described and discussed as below as a new species. Fig. 11 is copied in this monograph, PL LVIII, fig. 6c.) All the specimens representing this species are flattened by compression in the argillaceous shale, also more or less distorted. The outline of figure 6 (PI. LVIII) is probably the nearest the original outline of the ventral valve, and figure 6c of the dorsal. A ventral valve 6 mm. in length has the apex 1.5 mm. from the posterior margin. A cast of the interior of a ventral valve (PI. LVIII, fig. 6b) indicates a relatively large interior opening for the pedicle tube; a short, small visceral cavity with the shell thickened so as to form a short ridge; and an obscure false area; also that the posterior margin is arched slightly above the plane of the margin of the valve. An exterior cast shows the impression of a minute elongate tubercle on each side of the apex, and a small pedicle opening just back of them. A cast of the interior of a dorsal valve shows a short median ridge, and the posterior portion of the main vascular sinuses. The exterior cast shows that the surface was marked by small concentric ridges and lines of growiih, a few low, obscure, rounded, radiating ridges, and fine granulations or tubercles on very minute, irregular, more or less inosculating concentric ridges, or the same type of surface as that of Acrothele coriacea Linnarsson. If these shells were found at the same horizon in Sweden as A. coriacea I think they would be referred to that species except that the apex of the ventral valve of the French species is much nearer the posterior margin; more perfect specimens would probably show other differences. This species appears to differ from Acrothele quadrilineata Pompeckj and A. iohemica (Barrande) by the more anterior position of the apex of the ventral valve. In response to a request for permission to study the Cambrian brachiopods that he had collected from Montagne Noire, Mr. Miquel very courteously sent me a number, and among them I found this species, and, with his permission, have described it. It gives me pleasure to give the specific name in recognition of the discovery by Prof. J. Bergeron of the Middle Cambrian fauna of Herault, and his fine work on the fauna. Formation and locality. — Middle Cambrian: (342 [Miquel, 1893, p. 9]) Shales in Montagne Noire, Coulouma, Department of Herault, France. ACKOTRETIDiE. 639 AcEOTHELE BOHEMicA (Bairande) . Plate LVII, figures 1, la-d. Oholusf bohemicus Barrande, 1879, Systeme silurien du centre de la Boheme, vol. 5, pt. 1, PI. CII, figs, vn: 1-3. (Not described, but figured as a new species. Figs, vn: 1-2 are reproduced in this monograph, PI. LVII, figs. 1 and la, respectively.) Aerothele bohemica (Barrande), Walcott, 1886, Bull. U. S. Geol. Survey No. 30, p. 107. (Merely changes generic reference.) Aerothele bohemica (Barrande), Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, p. 101. (Suggests reference to Aerothele.) Aerothele bohemica (Barrande), Pompeckj, 1896, Jahrb. K.-k. geol. Reichsanstalt for 1895, Bd. 45, Hft. 3, pp. 509-511, PI. XIV, figs. 7-15. (Described and discussed in German. Figs. 8b, lib, and 10b are reproduced in this monograph, PL LVII, figs, lb, Ic, and Id, respectively.) Barrande did not publish a description of this species, but Pompeckj [1896b, p. 509] gives an extended description based on a large number of specimens. From this and the accom- panying illustrations it appears that the general form is much like that of Aerothele coriacea Linnarsson. It differs from the latter in having the apex nearer the posterior margin and in having a concentrically striated surface and undulating hnes instead of granulose surface; these characters also distinguish A. hohemica from A. {RedlicTiella) granulata (Linnarsson). The student should carefully examine the series of figures accompanying Pompeckj's descrip- tion as well as those of Barrande. Copies of the latter are inserted on Plate LVTI, figures 1 and la, and copies of Pompeckj's figures on Plate LVII, figures lb, Ic, and Id. The posterior position of the apex of the ventral valve suggests in this respect Aerothele prima (Matthew) (PI. LXI, fig. 6) and Aerothele prima costata (Matthew) (PI. LXI, figs. 4 and 4a), but in surface characters and outhne of the valves the species differ, as indeed they do in the apex of A. prima being nearer the margin than that of A. hohemica. Comparison should be made with A. quadrilineata Pompeckj, wliich is closely alhed to this species. The specific name is derived from Bohemia. Formation and locality. — Middle Cambrian : (345 [Pompeckj, 1896b, p. 509]) Greenish shale in the Paradoxides zone, on the Dlouhd Hora, above the brook of Sbirov, near Skrej; (345a [Pompeckj, 1896b, p. 511]) shales in the Para- doxides zone, on the right bank of the brook of Kardsek, near Tejfovik; (345b [Pompeckj, 1896b, p. 511]) in the "Bande de Jinec," at Felbabka and Jinec; and (345c) in Etage C [Barrande, 1879b, PL CII], at Mleschitz; all in Bohe- mia, Austria-Hungary. ' ACROTHELE BOBGHOLMENSIS Walcott. Plate LXIII, figures 2, 2a-b. Aerothele borgholmensis Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, pp. 84-85, PL VIII, fig. 12. (De- scribed and discussed as below as a new species. Figs. 12 and 12' are copied in this monograph, PL LXIII, figs. 2 and 2a, respectively.) General form subcircular to broad oval. Ventral valve subcorneal, with the apex a short distance back of the center. A clearly defined false area extends from the apex to the margin ; it is defined by a slight depression and a low ridge at the outer edges; two or three longitudinal fines extend to the margin, and the concentric Hnes of growth of the shell cross it without inter- ruption. An elongate, small foraminal aperture occurs just back of and beneath the apex. The outer surface of the shell is of a dull, dark color, and marked by sfightly undulating, clearly defined, concentric strife; the inner layers are marked by fine radiating and concentric fines. The shell is built up of tliin lamellee arranged in concentric layers that are sfightly obfique to the surface layer. Shell substance corneous. Nothing is known of the interior of the valves except the sharp median ridge of the dorsal valve. The largest specimen has a diameter of 4 mm. ; the average size is about 3 mm. Ohservations. — The convexity, position of the apex, and clearness of the false area depend upon the degree of compression and distortion the shells have received. I have described what appears to be the uninjured sheU. 640 CAilBRIAN BRACHIOPODA. The subcentral position of the apex seems to distinguish this species. It is associated with Oholus (Broggeria) salteri (Holl) and Lingulella lepis (Salter) . The specific name is derived from Borgholm, the type locality. Formation and locality. — Upper Cambrian: (310d) Ceratopyge slate at Borgholm, Oeland Island, Sweden. ACROTHELE CERATOPTGARtTM (BrOgger) . Plate LXIII, figures 1, la-c. Disdna (Acrotretaf) ceratopygarum Broggee, 1882, Die sUurischen Etagen 2 und 3, p. 47, PI. X, figs. 1, la-b. (De- scribed in German. Figs, la and lb are reproduced in this monograph, PL LXIII, figs. 1 and la, respectively.) Acrothele ceratopygonum Walcott, 1902, Proc. U. S. Nat. Mus., vol. 25, p. 598. (Mentioned in discussion of Acrotreta seebachi.) Acrothele ceratopygarum (Brogger), Moberg and Segerberg, 1906, Medd. irkii Lunds Geol. Faltklubb, Ser. B, No. 2 (Aitryck ur K. Fysiografiska Sallskapets Handl., N. F., Bd. 17), p. 67. (Mentioned in Swedish.) Acrothele barbata Moberg and Segerberg, 1906, idem, pp. 67-68, PI. Ill, figs. 7-10. (Described and discussed in Swedish as a new species.) Ventral valve conical, with eccentric apex. False area well defined and marked midway by a narrow, slightly elevated ridge that does not extend quite to the margin of the shell; on the interior of the shell a narrow furrow extends nearly to the margin where it is cut off by a transverse ridge just within the margin. Foraminal aperture minute, situated at the top of the false area just below the apex; in the exfohated shell it appears to be elongate. The outer surface of the shell appears in a cast to be nearly smooth; the inner layers or lamellae are marked by fine concentric and radiating lines. A cast of the interior shows a very small visceral area just in front of the apex, and a cardinal muscle scar on each side of the median hne back of the cast of the foraminal opening. The two ventral valves measure 5 mm. in diameter; height, about 2 mm. From Moberg and Segerberg's description [1906, p. 67] of the dorsal valve of Acrothele harhata the following is taken: "The dorsal valve is nearly flat, or with the posterior and cen- tral parts slightly arched; beak marginal." The interior shows a few traces of muscle scars. The interior of the ventral valve shows the main vascular sinuses and branches very much as in Acrothele coriacea Linnarsson (PI. LVI, figs, la. Id). These authors give the dimensions of one of the larger shells as, length, 5.25 mm.; width, 6 mm.; elevation, 1.5 mm. Observations. — Through the courtesy of Doctor Brogger I have had the opportunity of studying the type specimens of this species. One of them is illustrated (PI. LXIII, fig. Ic), and I have also copied two of Brogger's figures. The species is related to Acrothele horghol mensis Walcott from the Ceratopyge slate, but differs in the character of the false area and median ridge of the latter. It is also a larger and more convex form. Specimens from Vestfossen, Norway, one of which is illustrated on Plate LXIII, figure lb, have the same form as the shells described by Moberg and Segerberg under the name of Acro- thele harbata [1906, p. 67], and I find bits of the outer shell showing the "coarse, irregular, anastomosing, concentric ridges" characteristic of Acrothele barbata; a little trace of the marginal fringe is also shown on one specimen. The fact that the two species occur at the same strati- graphic horizon in Sweden and Norway, and the fact that they have the same specific characters, lead me to place A. barbata as a synonym of Brogger's A. ceratopygarum. This species derives its specific name from its occurrence ia the Ceratopyge limestone. Formation and locality. — Passage beds between the Upper Cambrian and the Ordovician: (3231i [Brogger, 1882, p. 17]) blue Ceratopyge limestone, at Vestfossen, 10 miles {16.1 km.) west-southwest of Christiania, Norway. (310 [Moberg and Segerberg, 1906, p. 67]) Ceratopyge limestone (zone 4), at Ottenby, on Oeland Island, Sweden. Acrothele colleni n. sp. Text figures 55A-E, page 641; Plate LXIII, figures 6, 6a-b. This species is represented by numerous specimens of both valves, but only the exterior of the valves is known. The ventral valve is subconical, with the apex a little in front of the ACROTRETID.E. 641 posterior third; the slope from the apex to tlie posterior margin is about 45° and that to the anterior margin 20°. The posterior slope is marked by a rather clearly defined false area, which is slightly flattened, and marked midway by a very slight depression; the apical opening is small, oval in outline, and situated on the posterior side of the apex. On finely preserved specimens the front and sides of the apical opening have a narrow, slightly elevated ridge, and a trace of a small tubercle on each side at the anterior end of the opening; the posterior margin arches very slightly beneath the false area. The dorsal valve is moderately convex and most prominent on the umbo, with the apex at the posterior margin. One of the largest ventral valves has a length of 9 mm.; width, 10 mm. The dorsal valve has a length of 7 mm.; width, 8 mm. These proportions vary somewhat as the shells are more or less distorted by compression in the shale. Shell substance corneous. The exterior surface is marked by very fine, concentric ridges of growth, with depressed and elevated lines between them; there are also mmierous low, rounded, narrow, radiating ridges that vary in strength and number on different specimens; on some shells there is hardly a trace of the radiating ridges, and on others they are numerous, especially on the sides: one dorsal valve shows nine on each side, with a few scattered through the central portion in addi- tion to the concentric and radiat- ing lines ; there is also a system of exceedingly minute and irregular, more or less inosculating, but, as a whole, concentric ridges, upon which very minute tubercles oc- cur. These are most perfect over the posterior half of the shell, but extend in many examples to the front margin. A cast of the apical portion of the dorsal valve shows that the pedicle aperture enlarged as it passed through the shell, and that the visceral area was short. Observations. — This species is of the Acrothele coriacea Linnars- son type. It has the same sur- face, except that the irregular, concentric ridges and tubercles are finer. The Lower Cambrian specimens from British Columbia appear to be identical with those from Montana and they are associated \\ath the same subfauna, of wliich Albertella Jielena Walcott is considered to be typical. The shells from the Mddle Cambrian, wliich occur 2,450 feet higher in the section on Mount Stephen, have the same form and surface markings and appear to be identical in all respects. It is interesting to note that Micromitra (Iphidella) pannula (White) has a similar vertical range. The specific name is given for Mr. M. Collen, of White Sulphur Springs, Montana, who collected the finest specimens at the locality on Scapegoat Mountain, Montana. Formation .and locality.— Middle Cambrian: (14s) About 2,300 feet (701 m.) above the Lower Cambrian and 2,700 feet (823 m.) below the Upper Cambrian, in the Ogygopsis zone of the Stephen formation [Walcott, 1908f, p: 210], on the northwest slope of Mount Stephen, above Field on the Canadian Pacific Railway, British Columbia, Canada. (4q) About 315 feet {96 m. ) above the unconformable base of the Cambrian and 190 feet (57.9 m. ) above the top of the quartzitic sandstones, in a shale which corresponds in position to the upper part of shale No. 6 [Lower Cambrian) of the Dearborn River section [Walcott, 190Sf, p. 202\ on the ridge between Gordon and Youngs creeks, about halfway between Gordon Mountain and Cardinal Peak, Ovando quadrangle ( U. S. Geol. Survey), Powell County, Montana. 62667°— vol 51, pt 1—12 41 L. FlGUEE 55.— Acrothele colleni n. sp. A, Slab showing a ventral and a dorsal valve (U. S. Nat. Mus. Cat. No. 51410a). B, Broken ventral valve showing false area (U. S. Nat. Mus. Cat. No. 61410b) (Xabont 4). C, A much larger ventral valve than that represented by B (U. S. Nat. Mus. Cat. No. 51410c). D, Cast of a ventral valve shomng the incurv- ing of the flexure hnes across the false area (U. S. Nat. Mus. Cat. No. 61410d) (X about 4). E, Dorsal valve (U. S. Nat. Mus. Cat. No. 51410e). The specimens" represented are from LocaUtj' 35c, a drift block of Lower Cambrian shales, on the slopes of Mount Bosworth, on the Continental Divide, 1 mile (1.6 km.) east of Hector, British Columbia. 642 CAMBRIAN BRACmOPODA. Lower Cambrian: (57e) About 115 feet (35 m.) below the Middle Cambrian, in limestone correlated with the top of Ic of the Mount W'hyte formation on Mount Boswortli [Walcott, 1908f, p. 213], just above the tunnel on the north shoulder of Mount Stephen, about 3 miles (4.8 km.) east of Field, British Columbia; (35c) drift blocks supposed to have come from the Mount Whyte formation [Walcott, 190Sf, p. 214], found on the south slope of Mount Boswortli, a short distance northwest of the Canadian Pacific Railway track between Stephen and Hector, eastern British Columbia; and (356) about 270 feet (82.3 m.) below the Middle Cambrian, in a greenish siliceous shale correlated with No. 3 of the Mount Whyte formation on Mount Bosworth [Walcott, 1908f, p. 214], in the amphitheater between Popes Peak and Mount AVhyte, about 3 miles (4.8 km.) northwest of Lake Louise, southwest of Laggan on the Canadian Pacific Railway, Alberta, Canada. (4v) About 200 feet (61 m.) above the unconformable base of the Cambrian and 75 feet (22.9 m.) above the top of the quartzitic sandstones, in a shale which corresponds in stratigraphic position to shale No. 6 of the Dearborn River section [Walcott, 1908f, p. 202], on Gordon Creek, 6 miles (9.6 km.) from South Fork of Flathead River, Ovando quad- rangle (U. S. Geol. Survey), Powell County, Montana. AcEOTHELE coRiACEA Linnarsson. Plate LVI, figures 1, la-i. Acrothele coriacea Linnarsson, 1876, Bihang till K. svensk Vet.-Akad. Handl., Bd. 3, No. 12, pp. 21-23, PI. IV, figs. 44-4S. (Described and discussed in English as a new species.) Acrothele coriace Linnarsson, Brogger, 1878, Nj't Magazin for Naturvidenskabeme, Bd. 24, Hft. 1, p. 76, PI. IV, fig. 11. (Mentioned.) Acrothele coriacea Linnarsson, Gronwall, 1902, Danmarks geol. Unders0gelse, Rsekke 2, No. 13, p. 40. (Localities mentioned in Norwegian.) General form subcircular to transversely broad oval in outline, with the posterior margin slightlj' transverse. Ventral valve slightly conical with the apex usually witliin the posterior fourth of the distance from the front to the back margin. The apex, as usually seen, is foniied of two minute, elongated tubercles with a narrow, elongate depression between them; at the posterior end of tliis depression a minute pedicle aperture occurs; on some shells the two minute tubercles unite in front so as to form a ring with a break at the back side just behind wMch the pedicle aperture opens. The size of the tubercles and median depression varies in different shells, and also with the amount of exfoliation of the outer shell. In some examples when the shell is nearly all exfoliated at the apex and umbo the two tubercles are prominent and a third tubercle occurs back of them which is the cast of the inner portion of the foraminal tube. A narrow false area is faintly defined on some shells and more distinctly on others. A median line often extends from the foraminal aperture to the margin. Casts of the interior show a much more distinctly defined false area, also that it is impressed in the shell. The striae of growth cross the area without interruption except as they curve slightly upward at the center on some shells. Linnarsson [1876, p. 21] states that there is no trace of a longitudinal groove as in Acrotreta subconica Kutorga; tliis is true of most specimens, but on others from the Para- doxides forcJihammeri zone, I find a narrow line and on others a curving upward of the concentric striae at the median line. The dorsal valve is slightly convex near the umbo, from which it curves rather abruptly down to the posterior margin and in some shells the lateral and anterior margins curve up a little, leaving a slightly concave surface between the margins and the umbo. The apex is near the posterior margin; it is divided midway by a narrow furrow so as to form a narrow elongate tubercle on each side. On some shells a slight depression or flattening extends to about the middle of the valve. The exterior surface is marked by concentric lines and striae of growth and slight undula- tions or ridges on the older shells ; a few rather faintly indicated, radiating costse occur on some examples of the ventral valve. Linnarsson [1876, p. 21] describes the outer surface as being rough, somewhat like leather. With a strong magnifier I find this to be caused by a minute granulation on fine, irregular, slightly elevated striae. The shiny inner layers of the shell are marked by concentric lines and very fine radiating lines. The shell is corneous and built up of numerous thin layers or lamellae so as to form a shell that is strong at the umbo and thin toward the margins. The largest ventral valve in ACROTRETID^. 643 the material available has a length of 8 mm. and a width of 10 mm. The average size is from 5 to 6 mm. in length, with a greater width. The interior of the ventral valve shows a rounded, slightly depressed visceral area, which foroas a semicircular area about the well-defined apical callosity and pedicle opening; back of the latter the false area is usually clearly defined. From each side and a little back of the pedicle opening in the ventral valve a rather strong main vascular sinus arches outward and then forward to the anterior half of the valve, where it divides into two or more branches; numerous lateral sinuses branch off and extend nearly to the margin, and a few shorter branches extend toward the central section. In the dorsal valve the vascular markings include the main vascular sinuses, which extend obliquely forward and outward, and an elaborate series of canals that originate in advance of the visceral area (PI. LVI, figs. Id and If). Our information as to the muscle scars of the ventral valve is limited to a suggestion of small cardinal scars on each side of the false area a little back of the main vascular sinuses. In the dorsal valve small cardinal scars (cl) occur on each side of the median ridge back of the base of the main vascular sinuses; small centrals (h) also occur on each side near the anterior end of the median ridge. Observations. — The above description is made from the study of a large number of speci- mens from several localities in Sweden, and a fine locahty on Bornholm Island, Denmark. It differs somewhat from Linnarsson's [1876, p. 21], chiefly as the result of my having more and somewhat better preserved material for study. He describes an umbonal muscle scar in the dorsal valve, but from his illustration [1876, PI. IV, fig. 4Sb] I am inclined to think that the scar is only a bit of the false area, the inner shell having been exfoliated. The relations of the species are with. Acrothele (Bedlichella) granulata (Linnarsson), from which it differs in smaller average size, more finely granulated surface, and, what is of more value, in the form of the muscle scars of the dorsal valve. This type of Acrothele is widely distributed. It is represented in Bohemia by A. loliemica (Barrande) and A. quadrilineata Pompeckj ; in France by A. hergeroni Walcott; in North Amer- ica by A. matthevn (Hartt) and its varieties; and in China by A. matthewi eryx Walcott. Formation and locality. — Passage beds between the Upper Cambrian and the Ordovician: (8x) Limestone at Slemmestad, about 3 miles (4.8 km.) southwest of Christiania, Norway. Upper-Middle Cambrian: (310i) Passage beds between the Middle Cambrian Paradoo!ddes forchhammeri zone and the Upper Cambrian Olenus truncatus zone at Borgholm, Oeland Island, Sweden. Middle Cambrian: o (leiiand 334h) Limestones of Paradoxides forchhammeri zone at Borregaard; (161) limestones of Paradoxides davidis zone at Borregaard; (334b) b Andi-arum limestone at Borregaard; (334c) 6 in the Paradoxides tessini zone at Borregaard; (334d) b in the zone with Agnostus parvifrons at Borregaard; (334f) limestone on Bornholm Island; (16j) limestone of Paradoxides forchhammeri zone at Laesaa; (16k) limestones of Paradoxides davidis zone at Laesaa; (334e) Andrarum limestone at Laesaa; all on Bornholm Island, Denmark. (8w) Limestones of the Paradoxides forchhammeri zone, at Andrarum, 20 miles (32 km.) northwest of Simris- hamn, Province of Christianstad; (330o)<: limestone band between the Holmia Icjerulfi zone and the Paradoxides tessini zone at Andrarum, 20 miles (32 km.) northwest of Simrishamn, Province of Christianstad; (320f) limestone at Andrarum, 20 miles (32 km.) northwest of Simrishamn, Province of Christianstad; (3201) drift blocks from the Paradoxides celandicus zone at Lillviken, near Oestersund, Jemtland; (320m) c limestones of the Paradoxides forchhammeri zone at Kinnehulle, northeast of Lidkqping, Province of Skarahorg; (320n) limestones of the Paradoxides forchhammeri zone at Lovened, Djupadal, 19 miles (30.6 km.) south-southeast of Skara, Province of Skaraborg; (321q) limestones of the Paradoxides forchhammeri zone at Munkesten, north of Hunneberg, Province of Skaraborg; (320r) limestones of the Agnostus lievi- gatus zone, at Hunneberg, western boundary of the Province of Skaraborg; (320y) limestones of the Paradoxides forch- hammeri zone at Gudhem, 12.5 miles (20.1 km.) south-southeast of Skara, Province of Skaraborg; (320b) limestone forming 2d of the Paradoxides zone, the Agnostus Ixvigatus horizon, at Gudhem, 12.5 miles (20.1 km.) south-southeast of Skara, Province of Skaraborg; (320v)c in the Paradoxides forchhammeri zone at Lanna, Hj'ulsta, Vinala, and Vrana, all four in Nerike; (320p) « limestones of the Paradoxides forchhammeri zone at Sodra Mockleby, southern part of Oeland Island; (320g) limestones of the Paradoxides forchhammeri zone at Borgholm, Oeland Island; and (320q) limestone form- ing 2c of the Paradoxides forchhammeri zone, at Alunbruk (alum works), southern part of Oeland Island; all in Sweden. (324b) Shales of Etage Ic [Brogger] at Krekling, in Sandsvar; (324c) shales of Etage Id at KrekUng, in Sandsvar; and (324a) shals of Etage Ic [Brogger] at Skrena, Skiensdalen; all [Christiania Univ. Min. Inst. Coll.] in Norway. a This species also occurs in Locality 320k. b Gronwall, 1902, p. 40. " Linnarsson, 1876, p. 23. 644 CAMBRIAN BRACHIOPODA. ACROTHELE DECIPIENS Walcott. Plate LVIII, figures 3, 3a-d. Acrothele dedpiem Walcott, 1897, Proc. U. S. Nat. Mus., vol. 19, p. 716, PI. LX, fig. 2. (Described and discussed as a new species. The specimen represented by fig. 2 is redrawn in this monograph, PL LVIII, fig. 3a.) General form of the ventral valve subcircular, usually a little longer than wide; moderately convex; apex at the posterior one-sixth to one-eighth of the valve. Pedicle aperture of medium size, situated on the posterior slope of the summit of the apex; the slope fi'om the apex to the posterior margin is rather abrupt; and very gentle to the front margin. The obscure false area, with a faintly defined groove down its center, is shown on some specimens. Dorsal valve oval, moderately convex, and marked by a shallow depression extending from the back to the front ; apex marginal. Surface marked by fine, concentric lines of growth, and very fine, somewhat irregular, and sometimes inosculating ridges upon which occur exceedingly minute tubercles which give a very finely tuberculated surface; some specimens show depressed, narrow, rounded ridges extending from near the apex to the margins; these ridges vary in size and number. Shell substance corneous. Nothing is known of the interior of the ventral valve except a cast of the apical callosity (PL LVIII, fig. 3a). The interior of the dorsal valve has a strong median ridge that extends forward beyond the center, and strong cardinal scars. Observations. — This species is of the Acrothele matthewi (Hartt) type. It has a similar surface, and the apex of the ventral valve is well toward the posterior margin. The interior of the dorsal valve suggests that of Acrotreta more than do most interiors of the dorsal valves of Acrothele. It has an unusually long and strong median ridge and cardinal muscle scars. Acrothele decipiens was found associated with fragments of Olenell'm in the fine gray lime- stone in the Lower Cambrian shale. Formation and locality. — lower Cambrian: (50) Shaly limestones, 1.125 miles (1.8 Tcm.) north of S toner, 10 miles {16.1 1cm.) east-northeast of York; and (346) limestone and shale a little south of Emigsville; both in York County, Pennsylvania. Acrothele dichotoma Walcott. Plate LX, figure 2. Acrothele? dichotoma Walcott, 1884, Mon. U. S. Geol. Survey, vol. 8, pp. 14-15, PI. IX, fig. 11. (Described and discussed as a new species. The specimen represented by fig. 11 is redrawn in this monograph, PI. LX, fig. 2.) Acrotreta dichotoTTM Walcott, 1886, Bull. U. S. Geol. Survey No. 30, p. 107. (Suggests reference to Acrotreta.) Acrotreta dichotoma (Walcott), Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, pp. 100 and 103. (Mentioned.) Shell of medium size, thin, corneous, nearly circular in outUne, the transverse diameter being a Uttle greater than the longitudinal. Ventral valve depressed, discoid, with the apex but slightly elevated above the general plane of the surface and situated about one-third the distance from the posterior to the anterior margin. The apex is exfoliated, but the inner layers show that it was perforate and that in the interior the shell was thickened about the pedicle opening. The shghtly depressed area is triangular in form, and extends to the posterior margin, gradually expanding to a width of a little less than its length; it appears to have been quite minute at first, just beneath the apex, and to have been filled in by successive addi- tions of the shell, so that the generally circular outUne of the shell has scarcely been broken by the very shght truncation of the posterior margin. The additions to the posterior margin of the false area are crowded together as little transverse ridges with fine striae between. The outer portion of the shell is largely exfoliated, but traces of radiating striae and con- centric Hues of growth are shown. The latter on the outer portion appear to have been con- tinuous with those crossing the pseudodeltidium. From each side of the apex a narrow, main vascular sinus gentlv diverges, extending toward the central portion of the shell. Transverse diameter, 7.5 mm.; longitudinal diameter, 6.75 mm.; elevation or convexity, about 0.75 mm. ACROTRETID^. 645 When describing this species in 1884 I was not aware that a false area was present on some ventral valves of the type species of the genus, and that the supposed muscle scars were the main vascular sinuses. This caused me to question the generic reference. The ventral valve of Acrothele dichotoma has the same general form as A. subsidua (White), but it has a thicker shell, and, so far as known, a concentrically striated surface. FoHMATiON AND LOCALITY. — Middle Cambrian: (58) Shaly limestone in upper beds of the Secret Canyon shale, east side of New York and Secret canyons, Eureka district [Hague, 1892, Atlas], Eureka County, Nevada. Acrothele gamagei (Hobbs). Plate LX, figures 5, 5a-c. Oholella gamagei Hobbs, 1899, Am. Geologist, vol. 23, No. 2, pp. 114-115, figm-ed. (Described, figured, and discussed as a new species.) Acrothele gamagei (Hobbs), Ghabau, 1900, Occas. Papere Boston Soc. Nat. Hist., No. 4, vol. 1, pt. 3, pp. 615-617; fig. 48, p. 617; PI. XXXI, figs. la-d. (Described and discussed. Fig. 48 is copied from the figure accompanying the preceding reference.) Acrothele gamagei (Hobbs), Shimee, 1907, Am. Jour. Sci., 4th ser., vol. 24, pp. 176 and 177. (New locality mentioned.) .4croiAeZe ^amajrei (Hobbs), Geabau and Shimer, 1907, North American Index Fossils, vol. 1, p. 200. (Character- ized.) General form subcircular to transversely broad oval in outline, with the posterior margin slightly transverse. Ventral valve slightly conical with the apex at about the posterior fifth of the length of the valve ; the apex is formed of two elongate tubercles with a slight depression between them; at the posterior end of the depression a small pedicle opening occurs; back of the pedicle opening a more or less indistinctly defined false area extends to the posterior margin ; the posterior margin of the valve arches slightly upward. The dorsal valve is gently convex with posterior portion curving slightly downward so as to fit closely into the upward-curving margin of the ventral valve; beak marginal. The surface is marked by narrow, concentric undulations of growth, a few obscurely defined, radiating ribs and fine, concentric, irregular, imdulating, elevated lines ; the latter have numerous minute tubercles on them over the central portions of the shell, and sometimes on the outer lines of the old shells ; this results in a finely granulated surface that may be seen with the aid of a strong lens. The concentric lines cross the false area with only slight irregularity. The shell appears to be corneous and built up of several thin layers or lamellae. The interior of the ventral valve shows an elongate depression on each side of the apex, a small visceral area, and not very strongly defined main vascular sinuses that originate back of the pedicle opening and curve forward into the body of the valve. The interior of the dorsal valve has a low, rounded, median ridge that extends forward of the center where it bifurcates; a narrow, sharp, median septum occurs on the posterior portion of the ridge; the main vascular sinuses originate near the posterior margin beneath the beak and extend obliquely forward into the valve. The only muscle scars seen are the elongate, oval central scars of the dorsal valve, which are situated on the slopes of the median ridge back of the transverse center of the valve. Ohservations. — As stated by Grabau [1900, p. 615] this is the Massachusetts representative oi Acrothele matthewi (Hartt) of the St. John formation of New Brunswick. With the additional information afforded by a collection made by WUliam P. Rust for the United States National Museum, the similarity between the two forms is still more striking; they have the same general form, surface, and convexity; but A. gamagei attains a larger size and differs in the position of its main vascular sinuses; the latter may be seen by comparing Plate LX, figures 5b and 5c, with Plate XLI, figures Ic and Id. The specific name was given in honor of Miss A. O. Gamage, of South Bristol, Maine. Formation and locality. — Middle Cambrian: (326b [Grabau, 1900, p. 617]) Braintree slate, below high tide about 100 feet {30. S m.) east of the quarry at East Braintree, Abington quadrangle ( U. S. Geol. Survey); and (5) siKceous shale on Hayward Creek, Braintree, Dedham quadrangle (U. S. Geol. Survey); both in Norfolk County, Massachusetts. 646 CAMBRIAN BRACHIOPODA. AcEOTHELE INTERMEDIA LinnarssoD. Plate LVI, figures 3, 3a-d. Acrothele intermedia Linnarsson, 1879, Sveriges Geol. Undersokning, Afhandl. och Uppsatser, Ser. C, No. 35, pp. 25-27, PI. Ill, figs. 40-44. (Described in Latin, and described and discussed in Swedish, as a new species. Figs. 40-44 are reproduced in tliis monograph, PI. LVI, figs. 3, 3a-d, respectively.) Acrothele intermedia Linnarsson, Gronwall, 1902, Danmarks geol. Undersfjgelse, Raekke 2, No. 13, p. 39. (Localities mentioned in Norwegian.) A comparison of the figures of Acrothele intermedia on Plate LVI, with those representing A. coriacea Linnarsson and A. (Redlichella) granulata (Linnarsson) on the same plate, shows very clearly that A. intermedia is related in form to both, but that it differs in narrowing pro- portionately more toward the posterior margin. Linnarsson [1879, p. 26] states that in surface characters it agrees more nearly with A. coriacea. The outer surface is described as having numerous fine concentric striie without granules. He gives [1879, p. 26] the dimensions of two ventral valves as "length 8 and 6 mm., width 9.5 and 7 mm., respectively." A dorsal valve 9 mm. in length has a width of 1 1 mm. I have not seen the type of this species, or found specimens of it in the collections received from Sweden. Five of Linnarsson's figures are reproduced on Plate LVI. Two of these show a somewhat different position and arrangement of the main vascular canals and branches of the ventral valve than in A. coriacea Linnarsson. Formation and locality. — Middle Cambrian: (16h) Limestones of the Paradoxides forchhammeri zone at Borre- gaard; and (334a [Gronwall, 1902, p. 39]) limestones of the Conocoryphe exsulans zone at Borregaard; both on Bom- holm Island, Denmai-k. (3201i) Shales in the Paradoxides tessini zone at Lovened, Pro\'ince of Skaraborg; (320i) limestones of the Coronatus zone, at Andrai'um, 20 miles (32 km.) northwest of Simrishamn, Province of Chi'istianstad; (320j) limestones of the Coro- natus zone, at Gislof, Province of Malmohus; and (320k) limestones of the Coronatus zone, at Kiviks Esperod, Province of Malmohus; all [Gronwall, 1902, p. 39] in Sweden. (320q) Limestone forming 2c of the Paradoxides forchhammeri zone at Alunbruk (alum works), southern part of Oeland Island, Sweden. Specimens that are rather doubtfully compared with Acrothele intermedia occur at the fol- lowing locality : Upper Cambrian: (304] [Mason College Coll.]) Lower Stockingford shales, Puxley Park I^ane, halfway up the path to the quarry, Atherstone, Warwickshire, England. Acrothele levisensis Walcott. Plate LXXXI, figures 12, 12a-b. Acrothele levisensis Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, p. 85, PI. VIII, fig. 13. (Described and discussed as below as a new species. Fig. 13 is copied in this monograph, PI. LXXXI, fig. 12.) Outline transversely broad ovate, ventral valve moderately convex at the apex, which is about the posterior fifth of the length of the valve; pedicle aperture small and situated on the slope back of and near the apex. Dorsal valve depressed convex, with a very gentle slope from the umbo to the front margin and a greater slope to the marginal beak. Surface marked by fine concentric lines and striae that cross the space back of the apex without apparent interruption. A compressed ventral valve 8 mm. in length has a width of 10 mm. A dorsal valve has a length of 7 mm. ; width, 8 mm. The cast of the interior of a compressed dorsal valve shows a median ridge that expands near the center of the valve, and a main vascular sinus on each side that has the same general course as in Acrothele coriacea Linnarsson. Observations. — In general form this species is much like Acrothele coriacea and related species. It differs from them in ha^nng a smooth surface except for the concentric lines and striae. The foiu' specimens representing tliis species were attached to a block in the collections of the Geological Survey of Canada, with specimens of Elkania desiderata (Billings). The specific name is derived from Point Levis, the type locality. Formation and locality. — Lower Ordovlcian: (319a [Geol. Survey Canada]) Levis shale, Point Levis, Province of Quebec, Canada. ACKOTRETID^. 647 ACKOTHELE MACTJLATA (Salter). Plate LVII, figures 2, 2a-b; Plate LVIII, figure 2. Oholella maadata (Hicks MS.) Salter, 1866, Kept. British Assoc. Adv. Sci. for 1865, p. 285. (Name merely listed.) Obolella maculata Salter, Davidson, 1868, Geol. Mag., vol. 5, p. 311, PI. XVI, figs. 1-3. (Described as below, and discussed. Figs. 1-3 are reproduced in this monograph, PI. LVII, figs. 2, 2a-b, respectively.) Oholella maculata Salter, Davidson, 1871, British Fossil Brachiopoda, vol. 3, pt. 7, No. 4, p. 341, PL L, figs. 18-21. (Copy of preceding reference. Figs. 18, 19, and 21 are copied from Da\ddson, 1868, PL XVI, figs. 1, 2, and 3, respectively.) Not Oholella maculata Delgado, 1904, Communicacoes Commissao Ser\'i9o Geol. Portugal, tome V, fasc. 2, p. 364, PL IV, fig. 24. (Described in French. This species is referred in this monograph to Acrothele villahoimensis.) The description by Davidson [1868, p. 311] follows: Shell small, transversely oval, valves moderately convex; 4 lines in length, by 5 in breadth. Beak very obtusely acuminated; front broadly rounded; greatest breadth at about the middle of the shell; surface smooth, marked only by fine concentric lines of growth. Interior incompletely known. From the above description it is not possible to refer this species to Acrothele, but the figure given of the interior of the dorsal valve clearly indicates that genus. All of the figures given by Davidson appear to be of dorsal valves. It would be interesting to know if the specimens illustrated by Davidson [1871, PL LIX, figs. 41a, 42a] as "Discma pileolus Hicks" are associated Avith the specimens illustrated as ''Oholella maculata Hicks" [Davidson, 1871, PI. L, figs. 18-21]. With oxu- present information it is difficult to make comparisons mth other species of AcrotTiele fm-ther than to call attention to the similarity of the interior of the dorsal valve to that of Acrothele subsidua (Wliite) (PI. LX, fig. Ik). Formation and locality." — Middle Cambrian: (318d [Davidson, 1871, p. 341]) Sandstone in the middle portion of the Menevian at Porth-y-rhaw, St. Davids; and (318]i) shales in the Menevian at St. Davids; both in South Wales. (318e) Lower portion of the Menevian, at Camlan; and (318f) lower portion of the Menevian at Gwynfynydd; both [Davidson, 1871, p. 341] in North Wales. ACKOTHELE MATTHEWI (Hartt). Plate LXI, figures 1, la-g. lAngula matthewi Hartt, 1868, Acadian Geology, by Dawson, 2d ed., p. 644, fig. 221. (Described as a new species. The specimen represented by fig. 221 is redrawn in this monograph, PL LXI, fig. la.) lAngula matthewi Hartt, 1878, idem, 3d ed., p. 644, fig. 221. (Copy of Hartt, 1868, p. 644.) Acrothele mattheivi (Hartt), Walcott, 1884, Bull. U. S. Geol. Survey No. 10, p. 15, PL I, figs. 4 and 4a. (Original description copied and species discussed. The specimen represented by fig. 4a was labeled by Hartt as "Oholus (Discina) nitidus," n. sp., and is redrawn in this monograph, PL LXI, fig. 1. Fig. 4 is drawn from the speci- men figured by Hartt, 1868, p. 644, fig. 221, and is redrawn in this monograph, PL LXI, fig. la.) Acrothele mattheioi (Hartt), Walcott, 1886, Bull. U. S. Geol. Survey No. 30, p. 109. (Mentioned as similar to Acro- thele subsidua.) Acrothele matthewi (Hartt), Matthew, 1886, Trans. Roy. Soc. Canada for 1885, 1st ser., vol. 3, sec. 4, No. 4, pp. 39^1, PL V, figs. 15 and 15a. (Original description copied and species redescribed and discussed.) Acrothele matthewi (Hartt), Walcott, 1891, Tenth Ann. Kept. U. S. Geol. Survey, p. 609. (Mentioned as closely allied to Acrothele suhsidua (White).) lAngula matthewi Hartt, 1891, Acadian Geology, by Dawson, 4th ed., p. 644, fig. 221. (Copy of Hartt, 1868, p. 644.) Acrothele matthewi (Hartt), Hall and Clarke, 1892, Eleventh Ann. Kept. State Geologist New York for 1891, PL III, fig. 24. (Fig. 24 is drawn from the specimen figured by Matthew, 1886, PL V, figs. 15 and 15a.) Acrothele matthewi (Hartt), Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, pp. 99 and 100, PL III, fig, 29. (Discussed. Fig. 29 is copied from fig. 24 of the preceding reference.) Acrothele matthewi (Hartt), Matthew, 1895, Trans. New York Acad. Sci. for 1894-95, vol. 14, p. 128, PL V, figs. 6a-b. (No text reference. Figs. 6a-b are copied from Matthew, 1886, PL V, figs. 15 and 15a, respectively.) Acrothele matthewi (Hartt), Matthew, 1902, Bull. Nat. Hist. Soc. New Brunswick, vol. 14, pt. 5, No: 20, pp. 397 and 402, PL XVII, figs. 5a-b. (Mentioned. Figs. 5a-b are copied from Matthew, 1886, PL V, figs. 15 and 15a, respectively.) Acrothele matthewi (Hartt), Matthew, 1903, Geol. Survey Canada, Rept. Cambrian Rocks Cape Breton, p. 104, PL V, figs. 5a-b. (Mentioned. Figs. 5a-b are copied from Matthew, '1902a, PL XVII, figs. 5a-b, respectively.) a The type locality is unknown. Davidson's figure 3 [186S, PI. XVI] has been designated as the type, but its locality is unknown. 648 CAMBRIAN BRACHIOPODA. Acrothele matihem (Hartt), Grabau and Shimer (in part), 1907, North American Index Fossils, vol. 1, p. 200, fig. 234f (not 234g). (Described. Fig. 234f is copied from Matthew, 1886, PI. V, fig. 15; fig. 234g from Matthew's figure, lS95a, PI. V, figs. 7a-b, of Acrothele matthem prima, now referred to Acrolhek prima.) General form subcircular to transversely broad ovate in outline, with the posterior margin slightly transverse. Ventral valve subconical in young shells, becoming depressed, with an elevated apex in the adult stages of growth. The apex is within the posterior fourth of the valve, usuallj^ about one-sixth the distance from the posterior to the front margios; it is formed of two minute, more or less elongated tubercles, with a depression between them at the posterior end of which a minute pedicle opening occurs; a specimen of the variety Acro- thele matthem multicosta Matthew shows a minute tubercle just back of the pedicle opening that looks as though it were part of a ring that formerly extended about the apex, the two side tubercles being other portions of the ring. A narrow false area is indicated on some shells; on others it is absent. Dorsal valve slightly convex on the umbo, and nearly flat over the anterior portions; apex marginal as far as can be determined from the compressed shells. The exterior surface is marked by concentric hnes and striae of growth and a few laminated ridges near the outer margins ; on some specimens of the ventral valve one or two low, obscure ridges extend forward from the apex to the front margin. The epidermal layer is also marked by fine granulations or papiUse that are thickly placed over the surface; on the outer portions the granules are closely spaced on the top of low, irregular, narrow ridges in the same manner as on Acrothele coriacea Linnarsson; the inner layers of the shell are shiny and marked by concentric lines and very fine radiating striae. ! The shell is corneous and built up of several thin layers or lamellae. A large ventral valve has a length of 7 mm. with a width of 8 mm. The interior of the ventral valve shows an apical callosity penetrated by the pedicle open- ing, and back of it the base of the main vascular sinuses ; the latter extend outward and forward to about the transverse center of the valve, and then forward, curving inward more or less; rather strong lateral branches extend outward at varying points; one specimen shows three branches and another seven branches; back of the base of the sinuses a narrow, depressed space extends to the margin of a very narrow area; these features are showii in a cast of the interior (PI. LXI, fig. Ic); the median depressed space corresponds to the false pedicle furrow in some species of Acrotreta (PI. LXV, figs. 3g, 3h). The interior of the dorsal valve has a very characteristic median septum that extends forward from one-fourth to one-half the length of the valve; also the posterior portions of the main vascular sinuses that originate in front of the beak and extend outward and then obliquely forward. Of the muscle scars only the minute umbonal scars of the ventral valve have been observed; these are minute and close to the anterior end of the false pedicle furrow. Observations. — In general form and size Acrothele matthewi is alHed to A. coriacea Lin- narsson. The interiors of the valves are also much alike, as may be seen by comparing Plate LVI, figures la-c, with Plate LXI, figures Ic and Id (ventral valves), and Plate LVI, figure le, with Plate LXI, figure Ig (dorsal valves). The main vascular sinuses of the ventral valve of A. matthewi are stronger than those of A. coriacea, and the outer, granular surface of the epidermal layer is also much coarser. Acrothele matthewi differs from Acrothele (Redlichella) granulata (Linnarsson) in its smaller size and in the markings on the interior of the ventral valve; the granulated outer surface of the two species is sumlar, the differences between them not being greater than the variations on different portions of the same shell. From A. avia Matthew and A. proles Matthew this species is separated by the surface characters. It is difficult to institute detailed comparisons of outline and form of A. matthewi and other species, as both it and its varieties are represented by compressed and more or less distorted shells. Acrothele matthewi is a variable species, and Matthew has proposed subspecific names for the most marked of the varieties. One variety {A. matthewi eryx) is recognized and named from China. A large form in Matthew's collection labeled "Acrothele cf. granulata" appears ACROTRETID^. 649 to comprise large shells of A. matthewi. In the larger shells the granules become coarser toward the outer margins and are more irregularly distributed over the surface. Of the varieties named by Matthew, "A. matthewi prima" appears to be of specific value on account of the position of the apex of the ventral valve. "Acrothele matthewi costata" is a variety of A. prima, and A. matthewi m,ulticostata and A. matthewi lata appear to be the only varieties remaining that are sufficiently persistent and definite to be recognized, and even these merge by many gradations into the typical forms of the species. The specific name was given in honor of Dr. G. F. Matthew. Formation and locality. — Upper Cambrian: (3) Shaly limestones 300 feet (91.4 m.) above the Paradoxides zone, Manuels Brook, Conception Bay, Newfoundland. Middle Cambrian: (la, 6n, and 61) Shales near the top of No. 6; (1) shales of zone A of No. 7; and (2) shales of zone B of No. 7; all in the Manuels Brook section [W-'alcott, 1891b, p. 261] on Manuels Brook, Conception Bay, New- foundland. (6g) Limestone near the base of the Middle Cambrian, the lowest horizon carrying Paradoxides, northwest side of Chappie Arm Harbor, about 1 mile (1.6 km.) from its head, Trinity Bay, Newfoundland. (2 1 and 2m) Limestones and shales at the base of the Paradoxides zone [Matthew, 1895a, p. 108] on Hanford Brook; (3011i [Matthew, 1886, p. 41]) shales of Division Ic of Matthew, on Hanford Brook; (301i)bedsof Division Ibl of Matthew, on Hanford Brook; (3011 [Matthew, 1886, p. 41]) shales of Division Id of Matthew, on Porters Brook, St. Martins; (301g [Matthew, 1886, p. 41])" sandstones of Division Ic of Matthew, at Portland (now part of the city of St. John); (2s) limestone in upper part of Paradoxides zone, at Hastings Cove [see Matthew, 1898b, p. 38], on Kennebecasis Bay, 0.5 mile (0.8 km.) northeast of Torryburn, on the Intercolonial Railway, northeast of S,t. John; (3b) shale at the base of the Paradoxides zone, at the head of Seeley Street, St. John; (301k [Walcott, 1884a, p.i6]) shales of the St. John forma- tion at St. John; and (301j [Walcott, 1884a, p. 16]) shales of the St. John formation at Ratcliffs MiUstream; all in St. John County, New Brunswick. ACEOTHELE MATTHEWI EETX Walcott. Plate LXI, figure 2. Acrothele matthewi eryx Walcott, 1905, Proc. U. S. Nat. Mus., vol. 29, p. 11. (Described and discussed as below as a new variety.) In form, convexity, and size the ventral valve of the only specimen representing this variety is very similar to the typical forms of Acrothele matthewi (Hartt) . The shell is partly exfoliated and shows a small oval pit about the pedicle opening and two narrow vascular sinuses that extend from a point nearly back of the pit about the pedicle opening, forward, and a httle outward, about one-third the length of the valve. The shell is buUt up of several layers or lamellse that are smooth and sliiny on the interior, except where slightly roughened by faint vascular markings and obscure radiating striae; the outer surface is duU and marked by concentric striae and lines of growth, and numerous fine, irregular, often anastomosing, elevated lines that give the surface a rough appearance. The ventral valve is nearly cii'cular, with a diameter of 6 mm. If this shell were associated with Acrothele m/itthewi in the Middle Cambrian rocks of New Brunswick, I should not hestitate to identify it with that species. In the absence of a series of specimens, and of representatives of the dorsal valve, it is not certain that it is identical with Acrothele matthewi. Formation and locality. — Middle Cambrian: (C4) Limestone nodules at the base of the lower shale member of the Kiulung group [Blackwelder, 1907a, pp. 37 and 40 (2d list of fossils), and fig. 10 (bed 4), p. 38], 3 miles (4.8 km.) southwest of Yenchuang, Sintai district. Shantung, China. Acrothele matthewi lata Matthew. Plate LXI, figure 3. Acrothele matthewi lata Matthew, 1886, Trans. Roy. Soc. Canada for 1885, 1st ser., vol. 3, sec. 4, No. 4, p. 41, PI. V, figs. 17 and 17a. (Described as a new variety. The specimen represented by figs. 17 and 17a is redrawn in this monograph, PI. LXI, fig. 3.) Acrothele matthewi lata Matthew, Hall and Clarke, 1892, Eleventh Ann. Rept. State Geologist New York for 1891, PI. Ill, figs. 25 and 26. (Fig. 26 is drawn from the specimen figured by Matthew, 1886, PL V, figs. 17 and 17a.) a This species also occurs in Locality 308h. 650 CMIBRIAN BRACHIOPODA. Acrothek maiihewi lata Matthew, Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, Pi. Ill, figs. 26-28. (No text reference. Figs. 27 and 28 are drawn from the specimen figured by Matthew, 1886, PI. V, \ figs. 17 and 17a. Figs. 26 and 27 are copied from figs. 25 and 26, respectively, of the preceding reference.) Acrothele mattheud lata Matthew, 1895, Trans. New York Acad. Sci. for 1894-95, vol. 14, PI. V, figs. 8a-b. (No text reference. Figs. 8a-b are copied from Matthew, 1886, PL V, figs. 17 and 17a, respectively.) Acrothele matthewi lata Matthew, 1903, Geol. Survey Canada, Rept. Cambrian Rocks Cape Breton, p. 104, PI. V, figs. 6a-b. (Mentioned. Figs. 6a-b are copied from Matthew, 1902a, PI. XVII, figs. 6a-b, respectively.) This variety is characterized by having a flatter rim that gives the valves a depressed appearance around the border. There are many variations that tend to unite it with typical examples of the species, but there is no difficulty in recognizing the typical forms of the variety. Formation and locality. — Middle Cambrian: (301 [Matthew, 1886, p. 42]) Sandstones of Division lb2 of Mat- thew, on Hanford Brook; (301a [Matthew, lS95a, PL V, fig. S]) fine-grained sandstones below the Protolenus-bearing shales and sandstones in Division IbS of Matthew, on Hanford Brook; and (301g fMatthew, 1886, p. 41]) sandstones of Division Ic of Matthew, at Portland (now a part of the city of St. John); all in St. John County, New Brunswick. Acrothele matthewi multicostata Matthew. Plate LXI, figures 5, 5a-c. Acrothele matthewi multicostata Matthew, 1897, Trans. Roy. Soc. Canada for 1897, 2d ser., vol. 3, sec. 4, No. 7, p. 168. (Characterized as a new variety.) This variety is distmguished from the typical forms of the species by the presence of ntunerous narrow, more or less obscure, radiating ribs. There is a gradation in this respect to typical forms of A. matthewi, where an occasional trace of ribs occur. The more anterior position of the apex of the ventral valve serves to distinguish tliis variety from A. prima costata, wMch occurs at a slightly lower horizon at the same locahty. This form owes its varietal name to the numerous radiating ribs upon its sheU surface. Formation and LOCALiTT.^Middle Cambrian: (2s and 2t) o Shales and interbedded limestone in the upper part of the Paradoxides zone, Eastings Cove [Matthew, 1898b, p. 38], on Kennebecasis Bay, 0.5 mile {0.8 km.) northeast of Torryburn, on the Intercolonial Railway , northeast of St. John; and (21) limestone at the base of the Paradoxides zone [Matthew, 1895a, p. 108], on Hanford Brook; both in St. John County, New Brunswick. Acrothele? minuta Walcott. Plate LXIII, figure 3. Acrothele? minuta Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 303. (Described as below aa a new species.) SheU miuute, 1.5 mm. in diameter, subcircular in outline, gently convex, with a slight median depression from the umbo to the anterior margin; back of the umbo there is a sharp median depression between minute ridges on each of wliich there are two points or nipples. Surface marked by fine concentric striae. Substance of shell apparently phosphatic. Tliis interesting little species is represented by a single specimen. The generic reference is somewhat doubtful. Formation and LocALrrr. — Middle Cambrian: (C6) Thin slabby limestone in the upper shale member of the Kiulung group [Black-welder, 1907a, pp. 37 and 41 (2d Hst of fossils), and fig. 10 (bed 12), p. 38], 2.5 miles (4 km.) southwest of Yenchuang, Sintai district. Shantung, China. Acrothele nitida (Ford). Plate LVIII, figures 4, 4a. Oholella nitida Ford, 1873, Am. Jour. Sci., 3d ser., vol. 5, p. 213. (Described as on p. 651 as a new species.) Obolella nitida Ford, Walcott, 1886, Bull. U. S. Geol. Survey No. 30, pp. 118-119, PI. XI, fig. 2. (Original descrip- tion copied. The specimen represented by fig. 2 is redrawn in this monograph, PI. LVIII, fig. 4.) Obolella nitida Ford, Walcott, 1891, Tenth Ann. Rept. U. S. Geol. Survey, p. 612, PL LXXII, fig. 1. (New localities mentioned. Figure copied from preceding reference.) Obolella nitida Ford, Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, p. 70. (Mentioned.) XXVIII, figs. 8 and 8e, respectively.) Shell minute; general form subcircular. Ventral valve moderately convex; beak small and shghtly incurved over a very low false area; pedicle opening minute exteriorly, with a slightly elevated, sharp ridge on each side a little in advance of the point of the beak; seen from the back, the minute aperture points backward from the bottom of a pit between the two short, sharp ridges; in a specimen from a layer of hmestone a short distance above in the section, the aperture is at the point of a small nipple-hke projection, apparently formed by the union of the ends of the ridges already described on each side of the aperture. Dorsal valve slightly convex, with a minute beak at the posterior margin. Surface dull when the outer layer of the shell is preserved; it is marked by a few very fine, concentric lines of growth. The inner surface is marked by concentric lines and a few fine radiating lines. The shell is formed of several layers or lamellae and is relatively tliin. The average diameter of the adult shell is from 1.75 to 2.25 mm.; the dorsal valve shghtly shorter than the ventral. The cast of the interior of the ventral valve shows a sUght, longitudinal, median elevation and two short, not very strongly marked main vascular sinuses; several specimens indicate a slight cavity just beneath the aperture, which probably represents the inner side of the pedicle tube. The interior of a dorsal valve shows main vascular sinuses quite close to the outer margin; also two small, rounded median depressions a short distance in front of the posterior margin. Ohservations. — This shell occurs in great abundance on the surface of shaly, gray Hme- stone, about midway of the strata referred to the Upper Cambrian in the House Range ACKOTKETID^. 669 section. It differs from L. nitens, which occurs a short distance above it in the section, and with which it is also associated, in having a less elevated ventral valve and a less convex dorsal valve; and from L. transversa in being more rounded in outline and less convex. It appears to be more nearly related in form to L. minuta (Hall and Wliitfield) ; it differs, however, materially in the character of the interior markings of the ventral valve, features which also separate it from L. girtyi Walcott and L. fennesseensis Walcott. Formation and locality. — ^Upper Cambrian: (30k) 1,150 feet (350.5 m.) above the Middle Cambrian and 2,175 feel {66:2.9 m.) belotv the top of the Upper Cambrian, at the top of the arenaceous shales and ■limestones forming le of the Orr formation [Walcott, 190Sf, p. 176]; and (31t) about 1,175 feet (358.1 m.) above the Middle Cambrian and 2,150 feet (655.3 m.) below the top of the Upper Cambrian, in the limestone forming Id of the Orr formation [Walcott, 190Sf, p. 176]; both on Orr Eidge, about 5 miles (8 km.) south of Marjum Pass, House Range [Walcott, 1908f, PI. XIII], Millard County, Utah. LlNNARSSONELL.4 NITENS Walcott. Plate LXXVIII, figures 7, 7a. Linnarssonella nitens WalcOtt, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, p. 91, PI. IX, fig. 7. (Discussed as below as a new species. Fig. 7 is copied in this monograph, PL LXXVIII, fig. 7.) The outUne of the valves and the exterior appearance of this shell are much like those of L. modesta. It differs in having on the ventral valve a low, distinct area, with the perforated apex directed backward on nearly the same plane as the umbo, or most elevated portion of the valve. The dorsal valve is more convex and its interior has a strong mechan ridge extend- ing forward from the posterior margin about two-thirds of the distance to the front margin, a feature but little developed in L. modesta. From L. minuta (HaU and Wlutfield) it differs in the Mgher apex of the ventral valve, and from L. transversa in the latter character and in the more circular outline of the aperture of the valves. A single specimen of L. modesta was found associated with this species. In size L. nitens varies from 1.5 to 2 mm. in diameter. Formation and locality. — TTpper Cambrian: (31t) About 1,175 feet (35S.1 m.) above the Middle Cambrian and 2,150 feet (655.3 m.) below the top of the Upper Cambrian, in the limestone forming Id of the Orr formation [Walcott, 190Sf, p. 176], on Orr Ridge, about 5 miles (8 km.) south of Marjum Pass, Hou^e Range [Walcott, 1908f, PI. XIII], Millard County; and (32g) about 2,575 feet (784.9 m.) above the Cambrian quartzitic sandstones, in a blue limestone about 2 miles (3.2 km.) southeast of Muskrat Spring, on the northwest face of Grantsville Peak, Stansbury Range, Tooele County; both in Utah. L1NNAESSONELI.A TENNESSEENSIS Walcott. Plate LXXIX, figures 3, 3a-k. . Linnarssonella tennesseensis Walcott, 1902, Proc. U. S. Nat. Mus., vol. 25, pp. 604-605. (Described and discussed as below as a new species.) Mcehina prima Walcott, 1905, idem, vol. 28, p. 313. (Name referred to, but it was not defined or used elsewhere. ") General fonn of ventral valve rounded subtriangular, moderately convex, with the beak curving gently over a very low false area nearly to the posterior margin. Pedicle opening minute and situated a little in front of the beak. Surface of sheU marked by fine concentric striae and Unes of growth. The interior surface shows a few fine, radiating striae. Shell rather thick and built up of several thin layers or lamellffi. The cast of the interior of the ventral valve shows small cardinal scars and a minute pedicle tube directed backward, very much as in Oholella atlantica Walcott (PI. LV, figs. ]f-h). The area is short, narrow, and di^dded by a deep, narrow pedicle furrow; on each side of the latter the area projects into the valve so as to form a shelf, with a thickening at the interior angle next to the pedicle fiu-row; the central ^nsceral area is confined mainly to the deep median groove; an elevated area about the anterior end of the groove probably served as the point of attachment of the central muscle; the main vascular sinuses are very strong and project well toward the front part of the valve; the composite cardinal muscle scars, which served o A shell is referred to as Meekina prima, but before the generic or specific description was published I found that the specimens were casts of the iaterior of Limmrssonella tennesseejisis. 670 CMIBEIAN BEACHIOPODA. as the point of attachment of the transniedian ami anterior hxterals, are situated close to the posterior laterrJ margin of the valve. The dorsal valve has a very short antl narroAV area, with a small but distinct slightly con- cave shelf-like projection in front of it; on each side near the posterior lateral margins a strongly defined cardinal posterior muscle scar occurs that served as the point of attachment of the transmedian, outside lateral, and middle lateral muscles. The central scars are a little in advance of the center of the valve. None of the specimens show the main vascular canals except at their base. The shells average about 3 mm. in diameter. Observations. — The material representing this species occurs as casts of the interior and exterior surfaces, in a fine argillaceous shale. It is owing to the removal of the shell substance by solution that the cast of the area and area-like shelf of the dorsal valve is so clearly shown, also the posterior muscle scars, visceral area, etc., of the ventral valve. The shell has the general outhne of Linnarssonella girtiji Walcott ; but it differs in having the ventral valve more acuminate, less convex, and in the apex curving over nearly to the posterior margin. It has the outline of L. 7ninuta (Hall and Whitfield), but not the strong vascular sinuses and small cardinal scars of the ventral valve of that species. The perforate ventral valve and large cardinal muscle scars relate this species to Linnars- sonella. The composite cardinal muscle scars, area, and projection of the inner angles of the area into the area of the ventral valve, and also the interior of the dorsal valve, suggest Dicel- lomus. The spondylium-like shelf of the dorsal valve, indicated in the cast, may be only the cast of the area projecting out into the valve (PI. LXXIX, fig. Ir, of Linnarssonella girtyi). The cardinal scars and slielf-like areas of the valve separate this species from Oholella. Formation and locality. — Upper Cambrian: (31t) About 1,175 feet (358.1 m.) above the Middle Cambrian and 2,150 feet (655.3 m.) below the top of the Upper Cambrian, in the limestone forming Id of the Orr formation [Walcott, 1908f, p. 176], on Orr Ridge, about 5 miles (8 km.) south of Marjum Pass, House Range [Walcott, 1908f, PI. XIII], Millard County, Utah. Middle Cambrian: (13) Sandstones of the Rome formation, 1.5 miles (2.4 km.) east of Post Oak Springs [Hayes, 1894, areal geology sheet], Roane County; (107b) shales in railroad cut in Bull Run, northwest of Copper Ridge [Keith, 1896b, areal geology sheet], 11 miles (17.6 km.) northwest of Knoxville, Knox County; and (12) sandy shale on Webbs Ridge in gap west of Simpson's farm, 6 miles (9.6 km.) northeast of Knoxville, Knox County; all in Tennessee. Linnarssonella teansveksa Walcott. Plate LXXVIII, figures 6, 6a-c. Linnarssonella transversa Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, p. 92, PI. IX, fig. 6. (Discussed aa below as a new species. Fig. 6 is copied in this monograph, PI. LXXVIII, fig. 6.) This is a small shell tliat at first sight suggests L. modesta; it differs from that species in the valves being more convex, transverse instead of circular, and in having stronger concentric striae, and, in some instances, radiating stride. A few fragments of the interior of the dorsal valve indicate that the main vascular sinuses are well out toward the outer margin, and that small circular depressions occur on each side of the median line, very much as in the dorsal valve of L. girtyi Walcott (PI. LXXIX, fig. Ir), and that two small central muscle scars are midway between the posterior and anterior margins of the valve. The average shell has a widtli of 2 mm., with a length of from 1.5 to 1.75 mm. L. transversa differs by its transverse outline from all other known species of the genus. Formation and locality. — Upper Cambrian: (30j) About 950 feet (289. G m.) above the Middle Cambrian and 2,450 feet (746.8 m.) below the top of the Upper Cambrian, near the base of the arenaceous shales and limestone forming le of the Orr formation [Walcott, 1908f, p. 176], on Orr Ridge, about 5 miles (8 km.) south of Marjum Pass, House Range [Walcott, 1908f, PI. XIII], Millard County, Utah. Linnarssonella ueania Walcott. Plate LXXVIII, figures 9, 9a-c. Linnarssonella urania Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, pp. 92-93, PI. IX, figs. 9 and 9a. (De- scribed and discussed as below as a new species. Figs, 9 and 9a are copied in this monograph, PI. LXXVIII, figs. 9a and 9c, respectively.) Shell minute, general form elongate oval. Ventral valve convex; apex minute and curved down nearly to the plane of the margin of the valve ; false area, if present, must be very narrow. ACKOTRETID^. 671 Pedicle opening situated on the umbo a short distance above the point of the beak; on some shells it opens on the plane of the surface of the valve, and on others it has a rounded, sUghtly elevated margin. Dorsal valve slightly convex, with a minute beak at the posterior margin. Surface of the shell glossy, with very fine concentric striae and Hues of growth. A ventral valve 2.5 mm. in length has a width of 1.75 mm. The dorsal valves are somewhat shorter in propor- tion to the width. A partial cast of the interior of the ventral valve shows a small visceral area in front of the pedicle opening. The interior of the dorsal valve is marked by a strong central ridge that extends from the beak four-fifths of the distance to the front margin; on each side of the median ridge, near the posterior margin, there is a rather large, clearly defined cardinal muscle scar. Observations. — This species differs from L. girtyi Walcott in not having a false area^ in the ventral valve, and also in the position of the pedicle opening. The incurved apex is more hke L. modesta, but the form of the ventral valve and the position of the pedicle aperture are quite different. Formation and locality.— Middle Cambrian: (55u) Limestones about 200 feet (61 m.) above the Eowbp Cam- brian [see Walcott, 1908f, p. 171], 0.25 mile (0.4 km.) below the Maxfield mine, in Big Cottonwood Canyon, on the west front of the Wasatch Mountains, southeast of Salt Lake City, Salt Lake County, Utah. Genus ACROTRETA Kutorga.o [ojipoct s-t the top: and -pijriJr, bored through.] Acrotreta Kutokga, 1848, Verhandl. Russ.-kais. min. Gesell. St. Petersburg for 1847, No. 12, pp. 259 and 260 (notes on genus), and p. 275 (described in German as a new genus; see p. 672 for translation). Acrotreta Kutorga, Morris, 1849, Annals and Mag. Nat. Hist., 2d ser., vol. 4, pp. 316 and 318. (Characterized and discussed.) Acrotreta Kutorga, Davidson, 1853, British Fossil Brachiopoda, vol. 1, Introduction, No. 3, p. 133. (Described and discussed aa a possible subgenus.) oThe synonymy for this genus does not give a complete record of the various genera under which the species now included in Acrotreta were formerly placed; it gives only those references in which the genus is discussed or described. To complete the record the following mere generic references are listed: Discina Shumard [1861, p. 221]. Acrotreta Billings |1865a, p. 210). Obolella Salter [1866, p. 2&3]. Discina Salter [1866, p. 285). Obolella Hartt [1868, p. 644). Lingula Barrande [1868a, p. 102; 1868b, p. 692). Obolella Davidson [1868, pp. 309 and 310). Acrotreta f Davidson [1868, p. 314). Obolella Davidson [1871, pp. 339 and 340). Obolella? Billings [1872b, p. 470). Acrotretti Meek [1873, p. 463). Obolella? Billings [1874, p. 69). Metoptoma Callaway [1874, p. 196). Acrotreta White [1874, p. 9]. Acrotreta Linnarsson [1876, p. 16). Obolella Linnarsson [1876, p. 19). Acrotreta Linnarsson [1877, p. 374). Acrotreta White [1877, p. S3). Obolella Callaway [1877, p. 669). Acrotreta Swanston [1877, PI. VII figs. 21a-c). Obolella Hartt [1878, p. 644). Obolella Linnarsson [1879, p. 27). Obolusf Barrande [1879b, PI. XCV: ii). Acrotreta Barrande [1879b, PI. XCV: vn]. Acrotreta Brogger [1882, pp. 45 and 46). Obolella Davidson [1883, p. 211). Acrotreta Davidson [1883, p. 213). Obolella Walcott [1884a, p. 16). Obolella? Walcott [1884b, PI. I, fig. Ic). Acrotreta Walcott [1886b, p. 98]. LingulellafM3.tVa.ew [1886, p. 33]. Acrotreta Matthew [1886, p. 30]. Acrotreta Swanston [1886, PI. VII, figs. 21ar-c). Linnarssonia Walcott [1887, p. 189). Linnarssonia Oehlert [1889, p. 1138]. Linnarssonia Walcott [lS89b, p. 36). Obolella Dawson [1888a, p. 55; 1888b, p. 55J. Acroi-it Walcott [1889c, p. 441). Linnarssonia Walcott [1889c, p. 442). Obolella {Linnarssonia) Dawson (1830, p. 53]. Linnarssonia Hall [1890, p. 55). Obolella Hartt [1891, p. 644). Acrotreta Walcott [1891a, p. 60S]. Linnarssonia Walcott [1891a, p. 610 and PI. LXVm, figs. 2a-d). Obolella Hall and Clarke [1892c, p. 103). Acrotreta Matthew (1892, p. 43; 1834, p. 87]. Linnarssonia Matthew [1893a, p. 125). Acrotreta Matthew (1895a, p. 126). Lingulella f Matthew [1895a, p. 127). Obolella WaUerius [1895, p. 65). Acrotreta WaUerius [1895, p. 66). Linnarssonia Matthew (1897, p. 169). Linnarssonia Schuchert [1897, p. 262). Linnarssonia Freeh [1897, PI. I^V, Dgs. 3a and Sti\. Lingulella? Matthew (1898a, p. 128]. ^croircto Walcott [1899, p. 449). Acrotreta Matthew [1901a, p. 275], Acrothyra ? Matthew (1901b, p. 304). Acrotreta Matley [1902, p. 142). Acrotreta? Matley [1902, p. 143]. Acrotreta Matley [1902, p. 144). Linnarssonia Matley [1902, p. 145). Lingulella (Acrothyra ?) Matthew [1902b, p. 390]. Acrothele Matthew (1902b, p. 404). Acrotreta Matthew (1902c, p. 109]. Acrotreta Walcott [1902, pp. 680-600). Acrotreta Wiman [1902, pp. 54 and 55). Obolella Wiman [1902, p. 66]. A crothele Matthew [1903, p. 103). Acrotreta Walcott (1905a, pp. 298-303]. Acrotreta Moberg and Segerberg [1906, pp. 64, 65, and 66]. Acrotreta Walcott [1908c, p. 245; 1908d, pp. 93, 94, 95, and 96]. 672 CAMBEIAN BEACHIOPODA. Acrotreta Kutorga, von Seebach, 1865, Zeitschr. Deutsch. geol. Gesell. for 1865, Bd. 17, Hft. 2, p. 341, (Discussed in German.) Acrotreta Kutorga, Davidson, 1871, British Fossil Brachiopoda, vol. 3, pt. 7, No. 4, p. 343. (Mentioned in discussion of Acrotreta nicholsoni.) Acrotreta Kutorga, Dall, 1877, Bull. U. S. Nat. Mus. No. 8, p. 12. (Mentioned.) Acrotreta Kutorga, Zittel, 1880, Handbuch der Pal*ontologie, Bd. 1, Abth. 1, p. 666. (Described in German.) Acrotreta Kutorga, Walcott, 1884, Mon. U. S. Geol. Survey, vol. 8, pp. 16-17. (Discussed.) Linnarssonia Walcott, 1885, Am. Jour. Sci., 3d ser., vol. 29, p. 115. (Described and discussed as a new genus.) Linnarssonia Walcott, Matthew, 1886, Trans. Roy. Soc. Canada for 1885, 1st ser., vol. 3, sec. 4, No. 4, p. 35. (Discussed.) Acrotreta Kutorga, Oehlert, 1887, Manuel de conchyliologie, by Fischer, p. 1266. (Described in French, with figures of "A. subconica.") iinnarssoma Walcott, Dawson, 1890, Trans. Roy. Soc. Canada for 1889, 1st ser., vol. 7, sec. 4, No. 3, pp. 53-54. (M'entioned in discussion of Acrothele pretiosa.) Acrotreta Kutorga, Hall and Clarke, 1892, Eleventh Ann. Rapt. State Geologist New York for 1891, p. 250. (Described.) Linnarssonia Walcott, Hall and Clarke, 1892, idem, p. 251. (Described.) Acrotreta Kutorga, Hall and Clarke, 1892, Forty-fifth Ann. Kept. New York State Museum for 1891, p. 566. (Copied from Hall and Clarke, 1892a, p. 250.) Linnarssonia Walcott, Hall and Clarke, 1892, idem, p. 567. (Copied from Hall and Clarke, 1892a, p. 251.) Acrotreta Kutorga, Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, pp. 101-104. (Described and discussed.) Linnarssonia Walcott, Hall and Clarke, 1892, idem, pp. 107-109. (Described and discussed.) Linnarssonia Walcott, Matthew, 1892, Trans. Roy. Soc. Canada for 1891, 1st ser., vol. 9, sec. 4, No. 5, p. 42. (Species referred to the genus mentioned.) Acrotreta Kutorga, Matthew, 1902, Bull. Nat. Hist. Soc. New Brunswick, vol. 4, pt. 5, No. 20, p. 390. (Stratigraphic range in Cape Breton discussed.) Acrotreta Kutorga, Matthew, 1903, Geol. Survey Canada, Rept. Cambrian Rocks Cape Breton, p. 94. (A copy ot the preceding reference.) Acrotreta Kutorga, Matthew, 1903, idem, pp. 96-97. (Notes on development of the genus.) Acrotreta Kutorga, Grabau and Shimer, 1907, North American Index Fossils, -vol. 1, p. 199. (Described.) f Linnarssonia Grabau and Shimer, 1907, idem, p. 200. (Described, but the only species referred to the genus {"L. -pretiosa") is not figured and it is impossible to tell whether the authors are discussing the Linnarssonia pretiosa that has been referred to the genus Acrotreta {Acrotreta sagittalis), or to the genus Acrothele {Acrothele pretiosa).) Acrotreta Kutorga, Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 4, PL XI, and pp. 142 and 146. (Classifica- tion of genus.) The original description by Kutorga follows: Dorsal valve highly conical; the hinge surface of the cone flat, in the form of a high triangle, similar to an area, with a shallow gutter-shaped depression running from the tip as far as the middle point, which (depression) here appears as an indication of a deltidium. At the upper end of this furrow, turned consequently to the hinge side, is found the obtusely oval external siphonal opening. Ventral valve flat, with a distinct marginal apex. On the surface of the shell are seen only delicate growth wrinkles concentric to the apex of the cone, which curve crescentially into the longitudinal furrow of the surface of the shell; no tubercles and no spines; hinge border rectilinear. The revised description of the genus is as follows : Ventral valve strongly convex to conical, with the posterior face more or less flattened to form a false area that is usually marked by a shallow median groove. Pedicle opening at the apex of the cone and directed more or less backward. Apex usually anterior to the posterior margin, but occasionally overhanging it. Dorsal valve slightly convex, with very small beak; area short and divided by a small false deltidium. Surface marked by fine concentric strise and lines of growth wMch cross the posterior face and the median groove; in addition there are on five species very fine, concentric, undulating, often inosculating, rounded ridges that form a surface like that of Oholus ( Westonia) ella (Hall and \^Tiitfield) (PI. XLVII, fig. 10). Acrotreta primseva Walcott (PI. LXIX) has this type of surface. A. claytoni Walcott (PL LXXF^) has fine, undidating strise, A. spinosa Walcott (PI. LXXIX) fine short spines, and A.? canceUata Walcott (PL LXXIX) a cancellated surface. The shell in all species where it is preserved is calcareocorneous and built up of several thin layers or lamellae that are arranged more or less obliquely to the outer surface toward the outer margin of tlie valves. ACROTKETID^. 673 The cast of the ventral valve shows that the interior of the shell has a rather strong cal- losity or apical swellmg penetrated by the foramina! tube, and on each side of and back of the callosity near the posterior margin the cardinal muscle scars, which usually take the form of a projecting boss or tubercle corresponding to a depression in the shell in which the trans- median and middle lateral muscles were probably attached. In front of the apical callosity in A. argenta Walcott there are two trapezoidal areas cori'esponding to similar areas in Ololella and Oholus, in which the central, outside, and middle lateral muscles were attached. The position and size of the areas are shown by Plate IjXVII, figures 5a and 5b. The grooves of the main vascular sinuses pass around the apical swelling and extend forward, diverging toward the anterolateral margins of the shell. The interior of the dorsal valve is almost invariably marked by a long, well-defined median ridge and a pair of strong cardmal tubercles near the margin of the area corresponding in position to tlie cardinal tubercles of the ventral valve. Smaller tubercles occur in advance of tlie posterior tubercles, one on each side of the median ridge; they are often replaced by elon- gate oval scars that correspond to the central scars of the dorsal valve of Oholus: the anterior lateral muscle scars are too minute to be clearly located, but they were undoubtedly close to the median hne a little in advance of the central scars. The cardinal tubercles of both valves often have scars on them indicating the attachment of muscles. Type. — Acrotreta suhconica Kutorga. Ohservations. — Of the t3^pe of the genus, A. suhconica Kutorga, onlj^ the external shell is known. In 1884 [1884b, PI. I, figs, lb and Id] I illustrated the interior of both valves of ".4. gemma" (see pp. 30-31), showing the area, median ridge, "cardinal tubercles," and central muscle tubercles of the dorsal valve, and the apical swelling and cast of the main vascular canals in the ventral valve. Matthew [1886, PI. V, figs. 13 and 13c] illustrated the interior of A. haileyi, showing the cast of a small tubercle on each side of the apical swelling. Hall and Clarke [1892c, p. 102] stated that they could not see the cast of these tubercles on the original specimen, and I have not been able to find them on any of the type specimens of A. haileyi received from Mat- thew. It frequently occurs that the casts of the short deep channel of the main vascular sinuses give rise to tubercles a little in advance of and close to the apical callosity (PI. LXX, fig. If), or it may be that the cast of the visceral cavity will take the form of tubercles in front of the cast of the apical callosity (PI. LXIV, fig. 2c). The intimate relations existing between Acrotreta and Linnarssonia became more and more apparent with the collection of better material representing the two species referred to the two genera. Girty, when selecting specimens for illustration, called my attention to the strong resemblance between them and suggested that Linnarssonia was a synonym of Acrotreta. In all essential characters this is true, and Linnarssonia, if retained at all, must be as a subgenus to include the depressed forms of Acrotreta, intermediate between the typical elevated species A. suhconica Kutorga and A. gemma Billings and the nearly flattened shells of AcrotJiele. In view, however, of the close similarity of the interiors of the valves of Acrotreta scJimalenseei Walcott, A. curvata Walcott, and A. Tcutorgai Walcott to "Linnarssonia transversa" (see Acrotreta sagitta- lis transversa (Hartt)), "'L." sagittalis (Salter), and "i." misera (Billings) there remains only the external form of the pedicle valve to distinguish the two genera; this latter character is not of generic importance in the presence of the gradation in elevation and outline between A. suhconica Kutorga and A. sagittalis transversa (Hartt), shown by A. idahoensis Walcott, A. schmalenseei Walcott, A. microscopica (Shumard), A. pyxidicula White, and A. sagittalis (Salter). When studj'ing the specimens of Acrotreta at hand in 1884 I believed that A. gemma Billings, of Newfoundland, included the western forms described by Meek [1873, p. 463] and White [1877, p. 53]. This conclusion was retained until the study of a large series fi'om each of the typical localities convinced me that there were a number of species and varieties grouped under A. gemma. The correct reference of these species and varieties is indicated in the table, pages 30-31, and taken up in detail in the synonymy of each of the diff'erent species. 62667°— VOL 51, pt 1—12 13 674 CAMBRIAN BRACHIOPODA. "Acrotreta? costata" Davidson [1883, p. 213] from the Llandeilo of Scotland does not appear to be an Acrotreta. The description and figures suggest a genus allied to Cyrtia HaU and Clarke [1894, p. 40] of the Silurian. The surface characters of Acrotreta have been considered to be very simple and confined to concentric lines and strias of growth and obscure radiating strise. This study of the species has resulted in the discovery that five species, A. hisecta Matthew, A. gemmula Matthew, A. infiata (Matthew), A. primseva Walcott, and J., sabrinse (Callaway), have a surface much like that of Oholus {Westonia) ella (Hall and Whitfield) (PL XL VII). Mention has been made of the cancellated and spinose species, and those with undulating concentric stride. It is evident that Acrotreta, like Acrothele and Micromitra, has varied surface characters that are of specific but not generic A^alue. The false area, with or without its vertical median groove, is a variable character. The area and median groove are well developed in the type A. subconica Kutorga (PI. LXXIII, figs. 2g, 2h) and in the species A. socialis v. Seebach (PI. LXXIII, figs. 4', 4a'). On A. attenuata Meek a narrow sharp furrow is present, but the false area is scarcely defined (PL LXIV, figs, lb", Ic", Id"). On A. idaJioensis Walcott the false area is clearly defined but there is scarcely a trace of the median furrow (PL LXV, figs. 1", la"-c"). On A. microscopica (Shumard) (PL LXVII, figs, la'-c') there is only a faint false area and no median groove. The vascular markings, muscle scars, and apical callosity of the ventral valve vary in relative size, position, and appearance, but they all have a common general character and positio^p. Usually the markings on the interiors of the valves are very faint, and often nothing can be seen but the apical caUosity and the base of the main vascular sinuses in the ventral valve, apd the median ridge in the dorsal valve. It would require many pages on which to record the variations, and as thej^ are illustrated by the figures on the plates I will not attempt it. Geographic distribution. — The httle shell of Acrotreta occurs in every country where any considerable development of the Cambrian fauna is known. The exceptions are northern India, Australia, and where the Lower Cambrian fauna predominates. The general distribu- tion is given on pages 105-106. Stratigraphic distribution. — Three species and one variety are known from the Lower Cambrian, one of which, A. primseva Walcott (PL LXIX, figs. 1, la-f), is one of the largest species of the genus. From the Middle Cambrian thirty-three species and ten varieties are known; the}^ range from the base of the terrane to its summit, and two, A. idahoensis Walcott and its variety alta and A . pyxidicula White, pass up into the Upper Cambrian, and the first species and its variety alta continue on up into the base of the Ordovician in Nevada. In the Upper Cambrian twenty-one species and thr.ee varieties are known and in the passage beds above seven species. In the Lower Ordovician seven species and one variety occur, of which one species and one variety also occur in the Cambrian. The stratigraphic range of the species is given on pages 105-106. Acrotreta argenta Walcott. Plate LXVII, figures 5, 5a-g. Acrotreta argenta Walcott, 1902, Proc. U. S. Nat. Mus,, vol. 25, pp. 580-581. (Described as below as a new species.) The material representuig this species is more or less crushed and broken, but a few speci- mens show the general form and characters. It belongs to the Acrotreta idahoensis Walcott group in having a wide false area, strongly marked apical callosity, and pedicle opening. The thickening in the posterior portion of the dorsal valve is also characteristic of the two species. The cast of the interior of a ventral valve (PL LXVII, fig. 5b) reveals what I have searched for unsuccessfully in hundreds if not thousands of specimens of this genus. I refer to the visceral area with the position of the point of attachment of the central and lateral muscles on each side of it, essentially as in Obolella and Obolus (PL VII). Formation and locality.— Upper Cambrian: (7x and 7y) Limestone ot the Emigrant formation [Turner, 1902, p. 265], about 2.5 miles (4 km.) southeast of Emigrant Pass; (8b') shales of the Emigrant formation [Turner, 1902, p. 26ol, ACKOTRETID^. 675 in a ravine on the east side of the road about 1 mile {1.6 km.) southwest of Emigrant Pass; and (7v) shales of the Emigrant formation [Turner, 1902, p. 265], 4.25 miles (6.8 km.) south-southeast of Emigrant Peak; all in the Silver Peak quad- rangle (U. S. Geol. Survey), Esmeralda County, Nevada. ACROTEETA ATTENUATA Meek. Plate LXIV, figures 1, la-o; Plate LXXIX, figures 6, 6a. Acrotreta attenuata Meek (in part), 1S73, Sixth Ann. Rept. U. S. Geol. and Geog. Survey Terr, for 1872, p. 463, footnote. (Listed as A. subconica Kutorga, and described in footnote as a possible new species. Specimens now referred to A. attenuata Var.? and A. idahoensis were also included ia this reference.) Acrotreta gemma Walcott (in part) [not Billings], 1884, Mon. U. S. Geol. Survey, vol. 8, pp. 17-18. (Specimens representing Acrotreta pyxidicula, A. curvata, and A. idahoensis alta were included with the specimens repre- senting A. attenuata when this description of A. gemma was written, but only the last two are known to have been figured: A. curvata, PI. I, figs. Id and le; and A. idahoensis alta, PL I, figs, la and lb. The specimens represented by PL IX, figs. 9 and 9a, can not be found at this time, but it is probable that they should be referred to A. idahoensis alta. Fig. Ic represented a specimen of Acrotreta sabrinx, and the specimen repre- sented by fig. If is missing.) Acrotreta gemma Walcott (in part) [not Billings], 1886, Bull. U. S. Geol. Survey No. 30, pp. 98-99. (Specimens now referred to Acrotreta pyxidicula and A. primxva were included with the specimens representing A. attenuata when this description of A. gemma was written, A. primseva being figured, PL VIII, figs. 1, la-b.) Acrotreta gemma Walcott (in part) [not Billings], 1891, Tenth Ann. Bept. U. S. Geol. Survey, p. 608. (Specimens now referred to Acrotreta pyxidicula, A. curvata, A. idahoensis alta, and A. primseva were included with the specimens representing -4. attenuata in this reference to A. gemma, the last three being figured: A. curvata, PL LXVII, fig. 5b; A. idahoensis alta, PL LXVII, figs. 5 and 5a; and A. primxva, PL LXVII, figs. 5c, 5d, and 5e.) Acrotreta gemma Walcott (in part) [not Billings], 1899, Mon. U. S. Geol. Survey, vol. 32, pt. 2, p. 449. (Specimens now referred to Acrotreta pyxidicula, A. curvata, A. idahoensis alta, and A. primseva were included with the specimens representing A. attenuata when this description of A. gemma was written, the last three being figured: A. curvata, PL LXII, fig. 2e; A. idahoensis alta, PL LXII, figs. 2a, and 2c; and A. primxva, PL LXII, figs. 2, 2b, and 2d.) Acrotreta attenuata Meek, Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 298. (Characterized.) The variations in the exterior form of the ventral valve of this species are so fully shown by the illustrations that it is unnecessary to enter into detailed description. The species is characterized by its elevated ventral valve and narrow, incurved false area. The specimens illustrated by Plate LXIV, figures 1, la, lb, and Ih, are from the material labeled by Meek as Acrotreta attenuata, and all the others are from the same geological area. Some of the forms of A. idahoensis alta (PI. LXV, fig. 4) look like A. attenuata, but the false area is different. Acro- treta Jcutorgai has a somewhat similar false area and elevation, but it is a less robust shell and the apex of the ventral valve is nearer the posterior margin. The former reference to A. gemma is explained under the description of the genus (p. 673). Shells with a distinctly marked false pedicle groove in the ventral valve occur in the shales of the Wlieeler formation of the Middle Cambrian of the House Range, Utah. The shells of this locality show fine interiors of both valves (PI. LXIV, figs, li-n, and PI. LXXIX, figs. 6, 6a). The interiors of the ventral valve are much like those of A. Jcutorgai Walcott (PI. LXV, figs. 3b, 3c). . Formation and locality.— Upper Cambrian: (61) Limestone in the Dunderberg shale [Walcott, 1908f, p. 184], a little south of the Hamburg mine, Eureka district [Hague, 1892, Atlas], Eureka County, Nevada. Middle Cambrian: (59) Limestone at the base of the western slope of Combs Peak, near the plain of Antelope Valley, Eureka district [Hague, 1892, Atlas], Eiureka County, Nevada. (3s) About 1,700 feet (518.2 m.) above the Lower Cambrian and 2,700 feet (823 m.) below the Upper Cambrian in the shaly limestones and calcareous shales of the Wheeler formation fV\'alcott, 1908f, p. 181] in the eastern part of Wheeler Amphitheater, east of Antelope Springs, House Range [Walcott, 1908f, Pis. XIII and XV]; (lOy) about 2,900 feet (884 m.) above the Lower Cambrian and 1,500 feet (457.2 m.) below the Upper Cambrian in the central part of the limestone forming la of the Marjum limestone [Walcott, 1908t, p. 179], about 1 mile (1.6 km.) south-southwest of Marjum Pass, House Range [lA'alcott, 1908f, PL XIIl]; and (3x) about 2,200 feet (670.6 m.) above the Lower Cambrian and 2,200 feet (670.6 m.) below the Upper Cambrian in the shaly limestones forming Id of the Marjum limestone [Walcott, 1908f, p. 180], 2.5 miles (4 km.) east of Antelope Springs, in ridge east of Wheeler Amphitheater, House Range [Walcott, 190Sf, Pis. XIII and XV]; all in Millard County, Utah. (91i) At the base of the limestone above the Wolsey shale [Walcott, 1908f, p. 202] on Beaver Creek, 5 miles (8 km.) north of York, and about 8 miles (12.8 km.) north of Canyon Ferry, Big Belt Mountains, Fort Logan quadrangle (U. S. Geol. Survey), Meagher County; (159) limestones north of West Gallatin (Gallatin) River, Gallatin County; (302) 676 CAMBRIAN BRACIilOPODA. limestones on the east side of West Gallatin {Gallatin) River, above Gallatin, Gallatin County; and (156a) limestones of the Flathead formation of Peale, north of East Gallatin River, near Hillsdale, Gallatin County; all in Montana. (4n) Limestone about 325 feet (99.1 m.) above the unconformable base of the Cambrian in divide at the head of Jackson Creek (locally known as Sheep Creek), a creek flowing into Jackson Lake about 0.5 mile (0.8 km.) south of its northwest corner, Teton Mountains, Grand Teton quadrangle (U. S. Geol. Survey), Uinta County; and (340d) lime- stone near the head of Bear River Canyon; both in Wyoming. ACKOTRETA ATTENUATA var. ? Walcott. Plate LXV, figure 2. Acrotretaattenuata Meek (in part), 1873, Sixth Ann. Rept. U. S. Geol. and Geog. Survey Terr, for 1872, p. 463, footnote. (These specimens were included by Meek with the specimens which he listed as Acrotreta suhconica and described in a footnote as A. attenuata. See also A. attenuata and A. idahoensis .) Acrotreta attenuata Meek, vaj.?, Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 298. (Reason given for separation as variety.) A shell mtli a distinctly marked false area is separated as a variety of Acrotreta attenuata. It is associated with the type specimen of A. attenuata. Formation and locality. — Middle Cambrian: (302) Limestone east of West Gallatin (Gallatin) River, above Gallatin, Gallatin County, Montana. Acrotreta babel Barrande. Plate LXXVII, figures 6, 6a-b. Acrotreta babel Bakrande, 1879, Systeme silurien du centre de la Boh^me, vol. 5, pt. 1, PI. XCV, figs, vii: 1-2. (Not described, but figured as a new species. Figs. 2A, 2B, and 2C are reproduced in this monograph, PI. LXXVII, figs. 6, 6a-b, respectively.) Tliis minute species is the only form, of this genus that has been identified from Bohemia by Barrande. It has the characters of the genus, and with the figures for comparison with other species it appears to be distmct from all others. Barrande [1879b, PL XCV, fig. vii: 1] illustrates a more conical shell from Trubin than that represented by figiu-es 6 and 6a, wliich may belong to another species and genus. Formation and locality.— Lower Ordovician: (303) Etage do, Konigshof; and (303a) Etage dS, Trubin; both [Barrande, 1879b, PI. XCV] in Bohemia, Austria-Hungary. Acrotreta baileti Matthew. Plate LXXVII, figures 2, 2a-d. Acrotreta baileyi Matthew, 1886, Trans. Roy. Soc. Canada for 1885, 1st ser., vol. 3, sec. 4, No. 4, pp. 36-37, PI. V, figs. 13, 13b-d. (Described and discussed as a new species. The specimens represented by figs. 13, 13c, and 13d are redrawn in this monograph, PI. LXXVII, figs. 2a, 2, and 2', respectively.) Acrotreta baileyi Matthew, Hall and Clarke, 1892, Eleventh Ann. Rept. State Geologist New York for 1891, PI. Ill, figs.. 28-30. (Figs. 28 and 30 are drawn from the specimens figured by Matthew, 1886, PI. V, figs. 13c and 13, respectively.) Acrotreta baileyi Matthew, Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, p. 102, PL III, figs. 32-34. (Discussed. Figs. 32-34 are copied from figs. 28, 30, and 29 of the preceding reference.) Not Acrotreta baileyi f Matthew, 1892, Trans. Roy. Soc. Canada for 1891, 1st ser., vol. 9, sec. 4, No. 5, p. 43, PI. XII, fig. 7d (referred to A. bisecta). Acrotreta baileyi Matthew, 1902, Bull. Nat. Hist. Soc. New Brunswick, vol. 4, pt. 5, No. 20, p. 395, PL XVI, figs. la-d. (Mentioned and dimensions given. Figs, copied from Matthew, 1886, PL V, figs. 13, 13b-d.) Acrotreta baileyi Matthew, Walcott, 1902, Proc. U. S. Nat. Mus., vol. 25, pp. 581-582. (Described and discussed as below.) Acrotreta baileyi Mattsew , 1903, Geol. Survey Canada, Rept. Cambrian Rocks Cape Bieton, p. 97, PL III, figs. la-d. (Mentioned. Figures are copied from Matthew, 1886, PL V, figs. 13, 13b-d.) General outline transversely oval, with the posterior margin more or less straight for less than one-half the transverse diameter of the shell. On the ventral valve the posterior margin is rounded in at the median furrow of the false area, and op the dorsal valve it curves gently from the cardinal slopes to the beak. The ventral valve is strongly convex with the apex about one-fourth the length of the valve from the posterior margin. The crushed condition of the shells does not permit ACROTRETID^. 677 decision as to whether the umbo or the apex is the most elevated part of the valve. False area defined by the incurving of the cardinal slopes so as to form a somewhat flattened, trian- gular space that is divided midway by a rather strong vertical furrow. Pedicle aperture rather large and opening obliquely backward. The dorsal valve is gently convex, with a minute marginal beak. Surface of shell marked by fine concentric strife and lines of growth, and possibly by fine radiating strife. I fail to find any traces of the radiating striae on specimens that have not been distorted by pressure, and it looks as though all radiatmg striae and lines are the result of lateral compression of the shell. The average length is about 3.5 mm.; width, 4 mm. (Dis- torted shells have a length of 4 mm.; width, 3 mm.) The cast of the interior of the ventral valve shows a strong apical callosity, a fair-sized pedicle opening, large cardinal scars, and a small visceral area in front of the apical callosity. Matthew [1886, p. 36, PL V, fig. 13c] describes and shows on his illustration two "minute muscle scars" close to the "umbonal tubercle" and on each side of the parallel striae. On one specimen I find what may have led Matthew to consider there were such scars, but on many others quite as well preserved there are no such indications, and they are not known in any other species of the genus. Hall and Clarke examined Matthew's type material, and stated [1892c, p. 102] that wdth the original material before them they were unable "to dis- tinguish anything more than the central callosity." The cast of the' interior of the dorsal valve shows a strong median ridge of variable length and size, large cardinal scars, and well- defined central scars. Observations. — Tliis species belongs with the series represented by A. sagittalis (Salter) and its varieties, and if uncompressed, nondistorted, well-preserved specimens could be obtained, it is quite possible that it would prove to be identical with A. sagittalis transversa (Hartt). Matthew [1886, p. 37] thinks it has a thinner shell, but that is not probable, as the apical callosity and cardinal scars of the ventral valve and the median ridge, cardinal and central scars of the dorsal valve all indicate a shell quite as thick as that of A. sagittalis and its varieties. Doctor Matthew kindly sent me the type and study material of this species from his private collection. Formation and locality. — Middle Cambrian: (300) Shaly sandstones, possibly of Division Id of Matthew, on Long Reach, Kings County; and (301) doubtfully in sandstones of Division lb2 of the " Protolenus zone" [Matthew, 1895a, p. 108] Hanford Brook, St. John County; both [Matthew, 1886, p. 37] in New Brunswick, Canada. ACKOTEETA BELLATULA Walcott. Plate LXXVIII, figures 4, 4a-d. Acrotreta bellatula Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, pp. 93-94, PI. IX, figs. 4, 4a-b. (Described and discussed as below as a new species. Figs. 4, 4a-b are copied in this monograph, PL LXXVIII, figs. 4, 4b, and 4d, respectively.) General outline subcircular to transversely broad oval, with the posterior margin of the ventral valve nearly straight beneath the false area. The ventral valve is moderately convex, with the apex a little in front of the posterior margin. False area defined by the incurving of the cardinal slopes so as to form a somewhat flattened triangular space that is divided mid- way by a narrow and rather shallow, vertical furrow; pedicle aperture of medium size and opening slightly backward. Dorsal valve nearly as convex as the ventral, except that it curves down in the posterior portion to a minute marginal beak. Surface of the shell marked by fine, concentric striae and lines of growth that show marked variations in their sharpness on different specimens, the older shells having a dark, dull sur- face giving the effect of a thin film over the striae; a few traces of radiating striae are shown on some shells. The average length of the larger shells is about 1.75 mm.; width, 2 mm. The interior of the ventral valve shows a small apical callosity, mmute pedicle tube, and vascular sinuses originating a Uttle back of the apical callosity; a cast shows that there were 678 CAMBRIAN BRACHIOPODA. medium-sized, elevated cardinal muscle scars. An interior cast of the dorsal valve indicates a median ridge that extended about four-fifths of the distance from the area to the front mar- gin. It also indicates medium-sized, elevated cardinal muscle scars. A second specimen shows a shorter median ridge, with small, elevated central muscle scars about halfway between the posterior and front margins of the shell. Ohservations. — This species belongs to the Acrotreta sagittalis (Salter) group. The low convexity of the ventral valve, posterior position of the apex, the strong cardinal muscle scars, and the strong median ridge, and the cardinal and central scars of the dorsal valve, are all features common to Acrotreta hellatula and A. sagittalis. It differs from A. sagittalis in the more posterior position of the apex and less convexity of the ventral valve, and from A. definita Walcott in its much smaller size and less elevated ventral valve. Formation -AND locality. — Hiddle Cambrian: (lOz) About g, 900 feet (8S4 m.) above the Lower Cambrian and 1,500 feet (457.3 m.) below the Upper Cambrian in la of the Marjum limestone [Walcott, 1908f, p. 179]; (lln) a horizon about 100 feet (30.5 m.) above (lOz); and (3w) about 2,350 feet (716.3 m.) above the Lower Cambrian and 2,050 feet (624.8 m.) below the Upper Cambrian in the central portion of Ic of the Marjum limestone [Walcott, 1908f, p. 180], in the long cliff about 2 miles (3.2 km.) southeast of Marjum Pass; both in the House Range [Walcott, 1908f, Pis. XIII and XV], Millard County, Utah. ACKOTRETA BELTI (Davidsou). Plate LXXVII, figures 8, 8a. Obolella belli Davidson, 1868, Geol. Mag., vol. 5, pp. 310-311, PI. XV, figs. 25-27. (Described as below as a new species. The specimens represented by figs. 25-27 are redrawn by Davidson, 1871, PI. L, figs. 15, 17, and 16, respectively, and the last two figures are copied in this monograph ; see note accompanying the following reference.) Obolella belli Davidson, 1871, British Fossil Brachiopoda, vol. 3, pt. 7, No. 4, pp. 340-341, PL L, figs. 15-17. (Copy of preceding reference; figs. 15-17 are copied (with slight changes) from figs. 25, 27, and 26, respectively, of the preceding reference. Figs. 16a and 17a are reproduced in this monograph, PL LXXVII, figs. 8 and 8a, respectively.) Obolella sagittalis belli Davidson, 1871, idem, description of figures, opposite PL L. (Species placed as a variety without explanation.) Not Linnarssonia belli? Matthew, 1892, Trans. Roy. Soc. Canada for 1891, 1st ser., vol. 9, sec. 4, No. 5, pp. 42^3, PL XII, figs. 7a-c. (This species is not specifically referred in this monograph.) Linnarssonia belli (Davidson), Matley, 1902, Quart. Jour. Geol. Soc. London, vol. 58, pt. 1, p. 145, figs. 17-18. (Char- acterized.) Not Linnarssonia of. belli Matthew, 1903, Geol. Survey Canada, Rept. Cambrian Rocks Cape Breton, pp. 209-210, PL XVI, figs. 3a-c. (Copies Matthew, 1892, pp. 42^3, PL XII, figs. 7a-c. The species is not specifically referred in this monograph.) The original description by Davidson follows: Shell small, less than a line in length by about 1 line in breadth; transversely oval; beak acuminated; front broadly rounded. Valves moderately convex and marked by concentric lines of growth. The internal characters agree pretty closely with those described in 0. sagittalis. Observations. — It is possible that with a good series of specimens of this species its relations to other species might be more accurately determined than Doctor Davidson was able to do. It is not probable iha.t Acrotreta sagittalis (Salter) persisted into Lower Tremadoc time, but with a genus where the specific characters are so limited and the variations within the same species considerable it is exceedingly difficult to determine the specific relations of a form represented by only a few not very good specimens. Acrotreta belli appears to belong to the A. sagittalis group of forms, but for the present I think it is quite as well to leave it as a species. Fokmation and locality. — Upper Cambrian : (305 [Davidson, 1871, p. 341]) Lower Tremadoc shales, Craig-y-dinas, North Wales. (304 [Matley, 1902, p. 145]) "Bronsil" shales at White Leaved Oak, Malvern Hills; and (304a [Groom, 1902, p. 110]) "Bronsil" shales in the Malvern Hills; both between Herefordshire and Worcestershire, England. Acrotreta bisecta Matthew. Plate LXVI, figures 7, 7a-e. Acrotreta haileyi f Matthew, 1892, Trans. Roy. Soc. Canada for 1891, 1st ser., vol. 9, sec. 4, No. 5, p. 43, PL XII, fig. 7d. (Characterized and discussed.) Acrotreta bisecta Matthew, 1901, Bull. Nat. Hist. Soc. New Brunswick, vol. 4, pt. 4, No. 19, pp. 275-276, PL V. figs. 5a-g. (Described and discussed as a new species.) ACROTRETID^. ' 679 Acrotreta bisecta Matthew, 1902, Bull. Nat. Hist. Soc. New Brunswick, vol. 4, pt. 5, No. 20, p. 394, PL XVI, figs. 2a-g. (Mentioned and figures of preceding reference copied.) Acrotreta sipo Matthew, 1902, idem, pp. 406-407, PL XVIII, figs. 1 and 2. (Described and discussed as a new species.) Acrotreta bisecta Matthew, Walcott, 1902, Proc. U. S. Nat. Mus., vol. 2.5, p. 5S2. (Described and discussed.) Acrotreta sipo Matthew, 1903, Geol. Sui-vey Canada, Rept. Cambrian Rocks Cape Breton, pp. 185-186, PL XVIII, figs. 1 and 2. (Copy of Matthew, 1902a, pp. 406-407, PL XVIII, figs. 1 and 2.) Acrotreta bisecta Matthew, 1903, idem, pp. 186-187, PI. XI, figs. 5a-g. (Copy of Matthew, 1901, pp. 275-276, PI. V, figs. 5a-g.) Acrotreta bisecta Matthew, Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 298-299. (Described and discussed as below.) Nearly all the ventral valves of this species are more or less compressed in the shale, thus decreasing the true elevation. Matthew [1903, PI. XI, fig. 5] illustrates a pointed, high, ventral valve, but does not state whether or not the figure is diagrammatic. Some of the casts in the shale indicate a sharply conical ventral valve. When the apex is broken off the cast of a median apical callosit}^ is seen, with the base of the cast of a medium-sized pedicle tube; the cardinal scars are small and nearly concealed by the cast of the strong main vascular sinuses. There is considerable range of variation in the size and length of the median ridge of the dorsal valve. One specimen (fig. 7d) shows a strong median ridge, cardinal and central scars, and deeply excavated false deltidium. Surface marked by fine concentric strice and lines of growth and very fine undulating strias that give the concentric strite a fretted appearance when examined by a strong lens. The most nearly related species appears to be A. sahrinse (Callaway) of the Sliineton shales. Matthew [1902a, p. 406] has described a shell as "Acrotreta sipo" that occurs with his "AsapheUus fauna." I am unable to detect any specixic chfferences between it and A. bisecta, from the same area. The specific name is due to the presence of a strong median ridge bisecting the dorsal valve. Formation and locality. — Upper Cambrian: (3q) Shale in Barachois Glen, 4 miles (6.4 km.) south of Little Bras d'Or Lake; (101) shale on east bank of Barachois River, 6 miles (9.6 km.) from Little Bras d'Or Lake; (10c and lOd) shales on west side of Barachois River, 0.125 mile (0.2 km.) north of Boisdale Road, opposite McMullin's place; (lOe, lOf, and lOg) shales on the east branch of Barachois River, 0.5 and 0.75 miles (0.8 and 1.2 km.), respectively, north of the crossroad from Boisdale to Upper Leitches Creek; (lOn) shale in ravine on east side of Barachois Glen, 3 miles (4.8 km.) from Barachois; (lOh) shale on small east branch of Barachois River, 0.75 mile (1.2 km.) north of the crossroad from Boisdale to Upper Leitches Creek; (13h) shale on east bank of Barachois River, 1.5 miles (2.4 km.) north of Boisdale; (307a [Matthew, 1903, p. 186]) shales of Division C3c2 of Matthew, on McLeod Brook = Barachois River; and (307 [Matthew, 1903, p. 1S7]) shales of Division CSc of Matthew, on McLeod Brook=Barachois River; all in eastern Cape Breton, Nova Scotia. (308 [Matthew, 1892, p. 43]) Shales of Division C3c of Matthew at Navy Island, St. John Harbor, New Brunswick, Canada. ACROTKETA?? CANCELLATA Walcott. Plate LXXIX, figures 5, 5a. Acrotreta f ? cancellata\7 AhcoTT, 1905, Proc. U.S. Nat. Mus., vol. 28, p. 299. (Characterized as below as a new species.) The onty specimen of this species in the collection has more the form of Micromitra than Acrotreta. In its overhanging false area it suggests Acrothyra. Whatever the genus to which it belongs may be, its cancellated surface serves to distinguish it from forms with wlaich it might otherwise be compared. The surface is formed hy very fine, raised, concentric lines or ridges of growth, crossed by sharp radiating lines, which are seen only between the concentric fines. Formation and locality. — Passage beds between the Upper Cambrian and the Ordovician: (305) Siliceous limestone on Roundtop Mountain, Eureka district [Hague, 1892, Atlas], Eureka County, Nevada. Acrotreta carinata (Segerberg MS.) Moberg and Segerberg. Text figures 56A-D, page 680. Acrotreta cf. socialis Brogger (in part), 1882, Die silurischen Etagen 2 und 3, pp. 46^7, PL X, figs. 2, 2a-b (not figs. 3^, which are not referred in this monograph). (Described in German.) Acrotreta carinata (Segerberg MS.) Moberg and Segerberg, 1906, Medd. fran Lunds Geol. Faltklubb, Ser. B, No. 2 (Aftryck ur K. Fysiografiska Sallskapets HandL, N. F., Bd. 17), p. 66, PL III, figs. 5a-c and 6. (Described in Swedish as a new species; see p. 680 for translation. The figures are reproduced in this monograph as figs. 56A-D, p. 680.) 680 CAMBRIAN BRACHIOPODA. The original description by Moberg and Segerberg follows: The species differs from Acrotreta circularis, to which in other respects it is closely related, by its more even area, sharply bounded on the sides. At the rectilinear posterior edge the area occupies about one-fourth of the circumfer- ence; that is to say, more than in the case of A. circularis. The apex is also placed somewhat nearer the posterior edge than in the last-named species. The smaller shell is only feebly arched, with marginal, .some- what overlapping umbo. By its large well-marked keeled area our species resembles A. socialis, from the Ceratopyge limestone of Norway. Observations. — This species has about the same size and general appearance as Acrotreta seebachi. It differs from it in the more anterior position of the apex and the strongly defined false area with a median ridge. Formation and locality. — Passage beds between the Cambrian and the Ordovician: (310) Ceratopyge limestone (zone 4), at Ottenby, on Oeland Island; and (309) Ceratopyge limestone (zone 4), at Fogelsdng, 5 miles (8 km.) east of Lund, Province of Malmohus; both [Moberg and Segerberg, 1906, p. 66] in Sweden. Acrotreta circularis Moberg and Segerberg. Text figures 57A-C. Acrotreta circularis Moberg and Segerberg, 1906, Medd. fran Lunds Figure 56.— ^croircto carinata Moberg and Segerberg. A, Top view of ventral valve. B, Back view of ventral valve. C, Side view of ventral valve. D, Dorsal valve. All X 8. The ventral is the type. The specimens represented are from Locality 309, the Ceratopyge limestone at Fogels&ng, Province of Malmohus, Sweden. The figures are copied from Moberg and Segerberg [1906, PI. Ill, Dgs. 5a-c and (ij. Geol. Faltklubb, Ser. B, No. 2 (Aftryck ur K. Fysiografiska Sall- skapets Handl., N. P., Bd. 17), pp. 65-66, PL III, figs. 4a-c. (De- scribed in Swedish as a new species; see below for translation. The figm-es are reproduced in this monograph as figs. 57A-G.) On both sides of the Top The original description by Moberg and Segerberg follows : The apex of the larger shell (ventral valve) is situated midway between the posterior edge and the center, or possi- bly (the apex itself is not preserved) somewhat closer to the center. On the posterior edge there is a slightly defined triangular area which has a median rounded ridge extending out from the apex. The area as a whole is also somewhat arched, not quite level; at the posterior edge it occupies about one-fifth of the entire circumference of the shell. The height (from the apex to the level of the edge of the shell) is about two-thirds of the breadth. Shell smooth, shiny, with fine concentric growth lines visible even on the area, where, however, they are feebler, apex where the shell, as above mentioned, has been removed, there is found a furrow which on the area is parallel with its nearest side edge, and in the opposite direction runs obliquely toward the side. In the dkection from the apex down toward the anterior edge the shell is quite arched. The species differs from Acrotreta socialis von Scebach, as known from examples from the forchharrvmeri zone, by its greater size, its distinct keeled area, and the more subcentral position of the apex, which again causes the arch to be less raised. Observations. -^Tliis shell is nearest to Acro- treta seebacU (PI. LXXVII, figs. 3, 3a). It differs in having the apex farther back from the posterior margin and in the strong median ridge on the false area. It is very close to Acrotreta carinata Moberg and Segerberg. Formation and locality. — Passage beds between the Cambrian and the Ordovician: (310) Ceratopyge lime- stone (zone 4), at Ottenby, on Oeland Island; and (309) Ceratopyge limestone {zone 4), at Fogelsdng, 5 miles (8 km.) east of Lund, Province of Malmohus; both [Moberg and Segerberg, 1906, p. 66] in Sweden. Acrotreta claytoni Walcott. Plate LXXIV, figures 3, 3a-b. Acrotreta claytoni Walcott, 1902, Proc. U. S. Nat. Mus., vol. 25, p. 583. (Described as below as a new species.) The material representing this species does not give sufficient data for tlie preparation of a detailed description. The only ventral valve is depressed by compression in the shale; it is transversely broad oval in outline, with the posterior margin nearly straight for a distance of A FiGTTEE S7.—AcrotTela circularis Moberg and Segerberg. A, view. B, Posterior view. C, Side view. All X S. The specimen represented is from Locality 309, the Ceratopyge limestone at Fogelsdng, Province of Malmohus, Sweden. The fig- ures are copied from Moberg and Segerberg [1906, PI. Ill, figs. 4a-c]. ACROTRETID^. 681 two-fifths of the diameter of the valve ; the false area is fairly well defined by the abrupt incurv- ing of the cardinal slopes; its median furrow is distinctly outlined, and it slopes forward to the apex, which is situated about two-fifths the distance from the posterior margin to the front margin. Pedicle aperture minute and directed upward from the extreme apex of the valve. Dorsal valve gently convex. Surface of shell marked by fine concentric strise and lines of growth, and very fine irregular, undulating striae that can be seen only by the aid of a strong lens. A partial cast of a dorsal valve from the same faunal horizon about 30 miles distant shows a well-defined median ridge and cardinal scars. Observations. — This species is most nearly related to Acrotreta primseva Walcott of the upper Olenellus fauna, at Pioche, Nevada. It differs in having a less elevated ventral valve and in the more advanced position of the apex and foraminal aperture. All the specimens known are also smaller than the average of A. primseva, the largest being 3 mm. in width and 2.5 mm. in length. The specific name is derived from Clayton Valley, near the type locality. Formation and locality. — Lower Cambrian: (41) Limestone in the Pioche formation [Walcott, 1908a, p. 11] on a ridge 2.5 miles (4 km.) northwest of the town of Cherry Creek, White Pine County, Nevada. (175) Shales carrying Olenellus on the divide between Clayton and Fish Lake valleys, about IS miles (24.2 km.) south- southwest of Silver Peak; (184) shales at the summit of the Silver Peak Range, 10 miles (16.1 km.) southwest of the town of Silver Peak; and (II) shales of No. 3 of the Silver Peak group. Barrel Spring section [Walcott, 1908f, p. 189 o], 2.5 miles (4 km.) south of Barrel Spring and 0.5 mile (0.8 km.) east of the road, in the extreme southeastern corner of the Silver Peak quadrangle; all in the Silver Peak quadrangle (U. S. Geol. Survey), Esmeralda County, Nevada. Acrotreta concentrica Walcott. Plate LXXVII, figures 1, la-b. Acrotreta concentrica Walcott, 1902, Proc. U. S. Nat. Mus., vol. 25, p. 583. (Described as below as a new species.) Shell small, outline subcircular to transversely broad oval; apex of ventral valve nearly central; false area indicated by a slight flattening of the valve on the posterior side, and a distinctly marked, but very narrow, median furrow. The elevation of the valve is about one- half its diameter. The dorsal valve is slightly convex and its cast is marked by smaU cardinal scars and a narrow median ridge that extends to the anterior third of the shell. A ventral valve is 1.25 mm. in diameter, and one dorsal valve is 2 mm. in length. Ohservations. — This species occurs at about the horizon of Acrotreta Icutorgai Walcott but is distinguished from that species and all others by the central position of the apex of the ventral valve. This form owes its specific name to the nearly central position of the apex of the ventral valve. Formation and locality. — Middle Cambrian: (96x) Limestone 1 mile (1.6 km.) north of Adairsville, 15 miles (24.2 km.) northwest of Cartersville, Cartersville quadrangle (U. S. Geol. Survey), Bartow County, Georgia. Acrotreta conula Walcott. Plate LXXV, figures 2, 2a-b. Acrotreta conula Wamott, 1902, Proc. U. S. Nat. Mus., vol. 25, p. 584. (Described as below as a new species.) Shell small. Ventral valve eccentrically cone-shaped, with a broadly oval transverse aperture. The apex is situated at the posterior third of the distance between the front margin and the posterior edge of the slightly indicated false area. A minute pedicle aperture occurs at the summit of the apex. Dorsal valve convex, with the minute beak at the posterior margin. The cast shows a well-defined median ridge with the central muscle scars well back on the valve. Surface marked by fine concentric strise and lines of growth. This form owes its specific name to the fact that the ventral valve is markedly cone-shaped. Formation and locality. — TTpper Cambrian : (310a) Shales of Olenus truncatus zone, Oeland Island, Sweden. a The species mentioned occur at two sligiitly different localities (11 and Iv), none of tlie species being common to botti localities. 682 CAMBRIAN BRACHIOPODA. ACROTKETA CONVEXA Walcott. Plate LXVI, figures 6, 6a-c. Acrotreta convexa Walcott, 1902, Proc. U. S. Nat. Mus., vol. 25, p. 584. (Described essentially as below as a new species.) Shell small, subcircular, valves convex. Ventral valve most elevated at the low apex, which is above the sUghtly transverse posterior margin. Dorsal valve somewhat less convex than the ventral valve, with its greatest elevation at the posterior third; beak minute, mar- ginal. Length and width of shell 1 mm. Shell substance very thin, but not proportionally thinner than other large forms. Surface marked by fine concentric striae and lines of growth. Casts of the interior of the ventral valve show a minute apical callosity and cardinal scars. The cast of the dorsal valve has a long median furrow and minute cardinal scars. Ohservations. — This minute shell occurs in the shales and in a fine-grained interbedded sandstone of the Upper Cambrian. It is characterized mainly by the convexity of the dorsal valve and the relatively low ventral valve, characters that point to its descent from a form Hke Acrotreta sagittalis. The cast of a dorsal valve represented by Plate LXVI, figure 6c, shows a great develop- ment of the cardinal muscle scars; this is abnormal or else the valve belongs to another species. Formation and locality. — Upper Cambrian : (3n) Thin-bedded sandstone on Salmon River, Oillis Hill, 13 miles (S0.9 Jem.) south of Marion Bridge; (lOe) shales on east branch of Barachois River, 0.5 mile (0.8 km.) north of the cross- road from Boisdale to Upper Leitches Creek; (101) shale on east bank of Barachois River, 6 miles (9.6 km.) from Little Bras d'Or Lake; and (lOi) shale in high bank on west side of Barachois River, just north of the Boisdale road; all in eastern Cape Breton, Nova Scotia, Canada. Acrotreta curvata Walcott. Plate LXVIII, figures 1, la-n. Acrotreta gemma Walcott (in part) [not Billings], 1884, Mon. U. S. Geol. Survey, vol. 8, pp. 17-18, PI. I, figs. Id and le (not figs, la, lb, Ic, and If; see below). (Specimens now referred to Acrotreta attenuata, A. pyxidicula, and A. idahoensis alta were included with the specimens representing A. curvata when this description of A. gemma was written, A. idahoensis alta being figured (PI. I, figs, la and lb). The specimens represented by PI. IX, figs. 9 and 9a, can not be positively located at this time, but it is probable that they should be referred to A, idahoensis alta. The specimens represented by PI. I, figs. Id and le, are redrawn in this mono- graph, PI. LXVIII, figs. Ig and 1 1, respectively. Fig. Ic represented a specimen of Acrotreta sabrinse, and the specimen represented by fig. If is missing.) Acrotreta gemma Walcott (in part) [not Billings], 1891, Tenth Ann. Rept. U. S. Geol. Survey, p. 608, PI. LXVII, fig. 5b (not figs. 5, 5a, 5c, 5d, and 5e; see below). (Fig. 5b is a copy of Fig. Id of preceding reference. Speci- mens now referred to Acrotreta attenuata, A. pyxidicula, A. idahoensis alta, and A. primxva were included with the specimens representing A. curvata in this reference to A. gemma, but only the last two were figured; A. idahoensis alta, PI. LXVII, figs. 5 and 5a, and A. primxva, PI. LXVII, figs. 5c, 5d, and 5e.) Acrotreta gemma Hall and Clarke (in part) [not Billings], 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, p. 102, fig. 55 (not figs. 56 and 57; see below). (Mentioned in the text and fig. 55 copied from Walcott, 1884b, PL I, fig. Id. The specimens represented by figs. 56 and 57 are referred in this monograph to Acrotreta idaho- ensis alta.) Acrotreta gemma Walcott (in part) [not Billings], 1899, Mon. U. S. Geol. Survey, vol. 32, pt. 2, p. 449, PL LXII, fig. 2e (not figs. 2, 2a-d; see below). (Fig. 2e is a copy of Walcott, 1884b, PL I, fig. Id. Specimens now referred to Acrotreta attenuata, A. pyxidicula, A. idahoensis alta, and A. primseva were included with the speci- mens representing A. curvata when this description of A. gemma was written, but only the last two were figured: A. idahoensis alta, PL LXII, figs. 2a and 2c, and A. primxva, PL LXII, figs. 2, 2b, and 2d.) Acrotreta curvata Walcott, 1902, Proc. U. S. Nat. Mus., vol. 25, p. 584. (Characterized essentially as below as a new species.) This is a clearly defined species and all that is known of it, with the exception of the very fine concentric surface stria?, can be illustrated. It belongs with Acrotreta idaJioensis Walcott and other species with a broad false area. It difi^ers from described species in the incurved apex of the ventral valve, the strong sinus of the dorsal valve, and the general aspect of the two valves. ACROTRETID^. 683 This form owes its specific name to the fact that the apex of the ventral valve is strongly incurved. Formation and locality. — Passage beds between the Upper Cambrian and the Ordovician: (203a) Lime- stones at base of Pogonip limestone, in the spur on Hamburg Ridge extending out southwest from Wood Cone, Eureka dis- trict [Hague, 1S92, Atlas'], Eureka County, Nevada. Upper Cambrian: (12p) About 225 feet (69 m.) above the igneous rocks in the limestones of the Reagan sand- stone, at the northwest extremity of the Arbuckle Mountains, about 4 miles (6.4 km.) east of Homer, Carter County, Oklahoma. ACKOTKETA DEFINITA Walcott. Plate LXIV, figures 2, 2a-g, 3, 3a-b. Acrotreta definita Walcott, 1902, Proc. U. S. Nat. Mus., vol. 25, pp. 584-585. (Described essentially as below as a new species.) For exterior outline, form, and convexity of the valve, the student is referred to the illustrations (PI. LXIV). It is to be noted that the false pedicle groove is very distinct and also broader than that of Acrotreta attenuata Meek. The interior of the ventral valve is beau- tifully shown by casts. One of these (fig. 2c) shows the strong vascular sinuses, cardinal scars, cast of apical callosity, and, just in front of the latter, two slight tubercles, which may be the cast of depressions corresponding to the foraroinal pits of AcrotJiele. The cast of the dorsal valve is also very instructive in showing the area, cardinal scars, median ridge, and central scars. Observations. — This large fine species differs from its nearest ally, Acrotreta idahoensis Walcott, in the false area and the details of the arrangement of the vascular markings and muscle scars of the interior of the valves. The Idaho shells occur in a dark argillaceous shale and were collected by R. S. Spence, of Evanston, Wyoming. The Eureka (Nevada) specimens (PI. LXIV, figs. 3, 3a-b) are from a shaly limestone. Acrotreta depressa (PI. LXVI, figs. 8, Sa-c) occurs at about the same stratigrapliic horizon, but it has, when imcompressed, a more elevated and sharper apex. Fokmation and locality. — Middle Cambrian: (55) Shaly limestone at the top of the Eldorado limestone [Wal- cott, 1908f, p. 184], east slope of Prospect Mountain, in New York Canyon, Eureka district [Hague, 1892, Atlas]; and (57) shaly limestone of the Eldorado limestone [Walcott, 1908f, p. 184], at the 7o6-foot (213.4 m.) level of the Rich- mond mine. Ruby Hill [Hague, 1892, p. 43, and PI. I, opposite p. 116]; both in Eureka County, Nevada. (55c and 163) « Spence shale inember of the TJte limestone [Walcott, 1908a, p. 8], about 50 feet {15.2 m.) above the Brigham quartzite and 2, 755 feet {839.7 m.) below the Upper Cambrian, in a ravine running up into Danish Flat from. Mill Canyon, about 6 miles {9.6 km.) west-southwest of Liberty, and 15 miles {24.2 km.) west of Montpelier, Bear Lake County, Idaho. (4o) Shale about 375 feet (115 m.) above the unconformable base of the Cambrian, in divide at the head of Jackson Creek (locally known as Sheep Creek), a creek flowing into Jackson Lake about 0.5 mile (0.8 km.) south of its northwestern corner, Teton Mountains, Grand Teton quadrangle (U. S. Geol. Survey), Uinta County, Wyoming. ACROTEETA DEPRESSA (Walcott). Plate LXVI, figures 8, 8a-c. Acrotreta gemma depressa Walcott, 1889, Proc. U. S. Nat. Mus. for 1888, vol. 11, pp. 441-442. (Reason given for separation as a new variety.) Linnarssonia sagittalis Walcott, 1889, idem, p. 442. (Mentioned.) Acrotreta gemma depressa Walcott, Matthew, 1902, Trans. Roy. Soc. Canada for 1902, 2d ser., vol. 8, sec. 4, No. 3, p. 109. (Copies Walcott, 1889c, p. 441, and proposes the species A. depressa.) Acrotreta depressa Walcott, 1908, Canadian Alpine Journal, vol. 1, No. 2, p. 245, PI. I, figs. 3, 3a-c. (No text refer- ence. Figs. 3, 3a-c are copied in this monograph, PI. LXVI, figs. 8c, 8c', 8a, and 8, respectively.) A group of depressed ventral valves in an arenaceous argillaceous shale led me [1889c, p. 441] to distinguish the shell as a variety of Acrotreta gemma Billings. Material received since 1889, from a black and finer shale, shows an elevated ventral valve much like that of A. idaTioensis alia Walcott, but at present I am unable to decide that the typical form of 1 163 is the type locality. 684 CAMBRIAN BRACHIOPODA. A. depressa (figs. 8 and 8') is the same as the elevated ventral valve represented by figure 8c, or that the latter is A. idaJioensis alta; neither form should be referred to A. gemma. A. definita (PI. LXIY, figs. 2, 2a-g) occurs at the same relative stratigraphic horizon as this species and it is about the same size. It differs in having a lower, less elevated, and less pointed apex on the ventral valve. This form owes its specific name to the fact that its ventral valve is depressed. Formation and locality. — Middle Cambrian: (14s) About 2, .300 feel (701 m.) above the Lower Cambrian and 2,700 feet {823 m.) below the Upper Cambrian in the Ogygopsis zone of the Stephen formation [Walcott, IBOSf, p. 210], at the great ''fossil bed," on the northwest slope of Mount Stephen; (57f) about 2,200 feet (670.6 m.) above the Lower Cam- brian and 2,800 feet (853.4 m.) below the Upper Cambrian in the limestone forming 1 of the Stephen formation [Walcott, 1908f, p. 209], about 0.5 mile (0.8 km.) east of the great "fossil bed " on Mount Stephen; (58j) about 1,900 feet (579 m.) above the Lower Cambrian and 3,100 feet (945 m.) below the Upper Cambrian, near the base of the lime- stone forming 2 of the Stephen formation [Walcott, 1908c, p. 238(7)], on the east side of Mount Stephen about 3,000 feet (914 m.) above the Canadian Pacific Railway track; and (58r) about 1,800 feet (548.6 m.) above the Lower Cambrian and 3,200 feet (975.4 m.) below the Upper Cambrian, in the limestones forming 2 of the Stephen formation [Walcott, 1908f, p. 211], in the amphitheater between Mounts Stephen and Dennis; all near Field on the Canadian Pacific Railway, British Columbia, Canada. ACROTEETA EGGEGRUNDENSIS Wiman. Plate LXX, figures 2a-d. Acrotreta eggegrundensis Wiman, 1902, Bull. Geol. Inst. Univ. Upsala, vol. 6, pt. 1, No. 11, p. 55, PI. II, figs. 23-29. (Described in German as a new species. The two specimens represented by figs. 29, 27, and 26, and fig. 24 are redrawn in this monograph, PI. LXX, figs. 2a-c and 2d, respectively.) Acrotreta eggegrundensis Wiman, Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 299-300. (Characterized as below.) This species is of a characteristic Middle Cambrian type of Acrotreta represented in America by A. idahoensis Walcott and A. Jcutorgai Walcott. The surface is marked by unusually strong lines and ridges of growth and the false area is well defined. It is quite distinct from other species of the genus in European formations. Carl Wiman [1902, p. 51] refers this species to the Olenellus sandstone series. The bowlder containing it also carried AparcMtes ? anderssoni, Hipponicharion mattJiewi, Obolus ( Westonia) hottnicus, Kutorgina?, TorelleUa Isevigata, and fragments referred to Olenellus. This fauna is essentially Middle Cambrian in its facies, and unless the fragments referred to Olenellus are indisputably of that genus, I am inclined to refer the bowlder and its contained fossils to the Middle Cambrian. The fact that Obolus ( Westonia) hottnicus is nearly identical with 0. ( W.) finlandensis of the Middle Cambrian of Finland also points to the Middle Cambrian age of the fauna. The specific name is derived from Eggegrund Island, the type locality. Formation and locality. — Middle? Cambrian: (311) Drift bowlder of coarse-grained, somewhat friable, glauconitic sandstone. No. 3 [Wiman, 1902, p. 57], on Eggegrund Island, about 25 miles {40 km.) northeast of Gefle, Province of Gefleborg; and (311a) drift bowlder of glauconitic sandstone [Wiman, 1902, p. 57], at Norrskedika, a little northwest of Osthammar, Province of Stockholm; both in Sweden. (Slid) Drift bowlder of glauconitic sandstone [Wiman, 1902, p. 57], south of Lumparstrommen, Aland Island, Finland, Russia. Acrotreta emmonsi Walcott. Plate LXV, figure 6. Acrotreta emmonsi Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 300. (Characterized as below as a new species.) Only the interiors of the two valves of this species are known. The one illustrated shows the distinct character of the vascular markings and muscle scars. The only shell with which it can be compared is the dorsal valve of Acrotreta idaJioensis Walcott (PL LXV, figs. If, Ig). This shell resembles Obolella, but its corneous test, cardinal muscle scars, and absence of area of the Obolella type prevent a reference to that genus. Fragments of Olenellus occur in the layer of limestone from which the specimens were obtained. ACROTRETID^. 685 The specific name is given in memory of Dr. Ebenezer Emmons, who studied and wrote of the Bald Mountain section. Formation and locality. — lower Cambrian: (35a) Shaly limestone on the west slope of the summit of Bald Moun- tain, S miles {4-8 km.) north-northwest of Greenwich, Schuylerville quadrangle ( U. S. Geol. Survey); and (38a) limestone 2 miles (3.2 km.) south of North Granville, on the road which turns south from the road running between that village and Truthville, 4 miles (6.4 km.) west-northwest of Granville, Fort Ann quadrangle (U. S. Geol. Survey); both in Washington County, New York. AcROTRETA GEMMA Billings. Plate LXVI, figures 1, la-b. Acrotreta gemma Billings, 1865, Geol. Survey Canada, Paleozoic Fossils, vol. 1, pp. 216-217, figs. 201a-f. (Described as below as a new species. The specimens represented by figs. 201b, d, e, and f are redrawn in this monograph, PI. LXVI, figs. 1, la-b, respectively.) Not Acrotreta gemma Walcott [1884b, p. 17; 1886b, p. 98; 1891a, p. 608; or 1899, p. 449]. (The specimens referred to Acrotreta gemma Billings in the references mentioned have been referred in this monograph to Acrotreta aitenuata, A. curvata, A. idahoensis alta, A. primxva, and A. pyxidicula, which see.) The original description by Billings follows: Shell very small, about 1 line in diameter; one valve nearly flat and the other acutely conical. Dorsal valve very gently convex, nearly circular; sides and front margin uniformly rounded ; posterior margin very obtusely angu- lated at the beak, on each side of which a portion of the cardinal edge, equal to one-fourth of the whole width of the shell, is nearly straight; umbo very small; beak apparently depressed to the hinge line and not projecting beyond it; cardinal angles compressed, broadly rounded; a wide, shallow, mesial sinus extends from the front marginabout half- way to the beak; elsewhere the valve is gently convex or nearly flat. Ventral valve acutely conical, with a flat triangular area which is perpendicular to the plane of the lateral margin, its base half the width of the whole shell. In the apex of this valve there is a minute circular aperture, and in one specimen a dark line extends from it down the middle of the area, which appears to represent the foraminal groove of this genus; but in two other specimens of the ventral valve, with the area well preserved, there is no indication of a groove. Surface with very fine concentric striae. Width of dorsal valve about 1 line; length about eight-ninths of a line. The height of the ventral valve is about 1 line. The form of this species is very like that of A. subconica Kutorga, but that species is twice the size of this and has the area distinctly grooved. Observations. — By the courtesy of Prof. J. F. Whiteaves, of the Geological Survey of Canada, I have had the opportunity of studj^ing the type material of this species. Nine speci- mens of the ventral valve were received, but none of the dorsal valve, as they could not be found. One specimen in a dove-colored limestone appears to belong to a distinct species, which I have named Acrotreta ovalis. The remaining specimens show some variation in the angle of slope of the sides of the ventral valve, but four of them are similar to the form illus- trated by Billings [1865a, p. 216]. The broad false area, with a scarcely perceptible impression of the path of advance of the pseudodeltidium, is clearly shown in one of the specimens, and faintly in others. Two shells have the apex broken off so as to expose the cast of a minute apical callosity and a small portion of the side of the cast of the main vascular sinus (PL LXVI, fig. lb). Acrotreta gemma belongs to the A. subconica Kutorga group of the genus, having a high "ventral valve and a distinct and broad false area. It differs from A. subconica in having a less elevated ventral valve and in the apex being in front of the posterior margin instead of extending over it. Acrotreta gemma has no strong specific relations with the forms from the Eocky Mountains that I identified with it. A. attenuata Meek has a high ventral valve, but the false .area is practically absent, a narrow, deep sulcus taking its place. A. idahoensis alta Walcott has the elevation and false area, but differs in the details of the area and the outline of the cross section of the ventral valve. It was this form that led me [1884b, p. 17] to consider thsLtA.gemma occurred in Nevada, and with the slight knowledge that I then had of the genus and species a -wide variation of form was given to A. gemma. As far as now known to me, the species is restricted to the type locality. Formation and locality. — Lower Ordovician: (314d [Billings, 1865a, p. 217]) Limestone of Division P of the "Quebec group," 4 miles (6.4 km.) northeast of Portland Creek, Newfoundland. 686 CAMBRIAN BRACHIOPODA. AcROTRETA GEMMULA Matthew. Plate LXVI, figures 3, 3a-c; Plate LXXVII, figures 5, 5a-f. Acrotreta gemmula Matthew, 1894, Trans. Roy. Soc. Canada for 1893, 1st ser., vol. 11, sec. 4, No. 8, pp. 87-88, PI. XVI, figs. 2a-d. (Described as a new species. The specimens represented by figs. 2a and 2b are redra'wn in this monograph, PI. LXVI, figs. 3a and 3b-c, respectively.) Acrotreta gemmula Matthew, 1895, Trans. New York Acad. Sci. for 1894-5, vol. 14, p. 126, PI. V, figs. 5a-d. (Changes stratigraphic range. Copies figures from preceding reference.) Acrotreta gemmula Matthew, 1903, Geol. Survey Canada, Kept. Cambrian Rocks Cape Breton, p. 97, PI. Ill, figs. 4a-d. (Mentioned. Figures copied from Matthew, 1894, PI. XVI, figs. 2c, 2d, 2a, and 2b, respectively.) Shell small, nearly circular m oiitline, with the posterior margin slightly straightened. Height of ventral valve above the posterior margin about one-half the length of the valve. Apex slightly incurved over the false area, which varies from nearly vertical to an appreciable forward slope from the margin. False area mth rounded lateral margins and a rather strong median groove that terminates in a sulcus at the margin and begins at a minute foraminal aperture just beneath the apex. The position of the pedicle aperture causes it to open almost directly backward. The dorsal valve is moderately and rather uniformly convex. Surface of shell marked by fine, concentric striae and lines of growth, and toward the outer margin by very fine, undulating, concentric strife that give the surface, when examined by a strong lens, the fretted appearance shown on a larger scale on Oholus ( Westonia) ella (Hall and Whit- field) and a few species of Acrotreta. The size of the shell is about that of Acrotreta convexa Walcott, 1.5 to 2 mm. indiameter. The shell appears to have been rather thin, as it is indented by the pressure of the fine grains of sand of the matrix, and often bends rather than breaks when compressed. It is buUt up of very thin layers or lameUse that in the dorsal valve form a thickened rim. The cast of the interior of the ventral valve indicates a small but distinctly marked apical callosity penetrated by a rather strong pedicle tube that is directed backward at an angle of about 45°. A trace of the main vascular sinuses is shown at the anterolateral edges of the apical callosity; the casts of the cardinal scars are rather large for so small a shell. The interior of the .dorsal valve is marked by a rather strong median ridge, large cardinal scars, and small central scars. One of the strongly marked characters is the strong outer rim. This is a very clearly defined species and the oldest of the Acadian representatives of the genus, occurring, as it does, just below the " Protolenus fauna." The position of the pedicle aperture is similar to that of many species of AcrotJiele and is unusual for the genus, and may be of generic or subgeneric importance. In the collections made byLoper on Dugald Brook this species occurs with O&oZws (Palseoiolus) hretonensis (Matthew) in beds beneath AcrotJiyra proavia (Matthew) . He collected a fine series of this species at the same horizon from which Matthew obtained the types of his ' 'Acrotreta papillata' ' (see AcrotJiyra sera (Matthew), p. 718). I find that when the outer surface of the shell is well preserved it has a sHghtly fretted or pitted appearance on specimens from Hanford Brook and also Dugald Brook. Those from Dugald Brook show radiating lines when the thin outer layer of the shell is exfoliated. In some layers of rock all the shells are finely pitted, evidently by the fine grains of quartz sand in the matrix being pressed against the shell; in other layers the shells are identical in surface markings and form with those of A. gemmula from Hanford Brook. The interiors of the dorsal valve are not sufficiently well preserved for comparison, but in the ventral valve they are essentially the same. In each locality there is considerable variation, in the form and size of the apical callosity. Formation and locality. — Middle Cambrian: (301a [Matthew, 1894, p- 88]) Fine-grained sandstones below the Protolenus-bearing shales and sandstones in Division IhS of Matthew on Hanford Brook; and (301 [Matthew, 1895a, p. 126]) sandstones of Division lb2 of the "Protolenus zone " of Matthew on Hanford Brook; both in St. John County, New Brunswick. (lOp) Sandstone just below the waterfall in Division E2b of Matthew's [1903, p. 21] Etcheminian, Dugald Brook, Indian River; and (lOp") sandstone on the small brook on the hill between the bridge over Indian River and McPhees Brook; both in eastern Cape Breton, Nova Scotia, Canada. ACROTRETID^. 687 ACROTRETA GRACIA Walcott Plate LXVI, figures 5, 5a-d. Acrotreta ffrada Walcott, 1902, Proc. U. S. Nat. Mus., vol. 25, pp. 586-587. (Described and discussed essentially as below a3 a new species.) Shell small, slightly transverse; apex of ventral valve about one-third the length of the shell from the posterior margin; height about two-thirds the length of the shell; false area defined by the sharp rounding of the cardinal slopes and the transverse posterior margin, which is indented by the strong, broad, median groove extending from the margin to the apex, where it almost comes in contact with the minute apical pedicle opening. Dorsal valve moderately convex mth a nearly straight or gently curved posterior margin ; beak minute, marginal. Sur- face of shell marked by fine concentric strise and lines of growth. Shell strong and built up of thin layers or lamellae that over the central and anterior portions are more or less obhque to the outer surface layer. The cast of the ventral valve indicates a smaU but very clearly marked apical callosity; rather small cardinal scars and main vascular sinuses. The false area is narrow and broken midway by a rather wide, sUghtty arching false deltidium. The cast of the ulterior of the dorsal valve shows a broad, low, median ridge extending to about the anterior third of the length of the valve, large cardinal muscle scars, and small main vascular sinuses that arch inward after passing the central scars, and then outward. Ohservations. — This species is distinguished by the strong shell, broad median ridge of the dorsal valve, and deep median groove of the false area of the ventral valve. The light color of the shell may be o^nng to the character of the limestone in which it is preserved, or it may be that it is a little more calcareous than other species of the genus. The Acrotreta which Matthew [1897b, p. 169] describes and illustrates from the Hastings Cove locahty (" Linnarssonia beiti magna") is characterized by a narrow median ridge in the dorsal valve and other characters not present in A. gracia. In the Paradoxides zone on Han- ford Brook I found numerous examples of a species of Acrotreta that appears to be identical with the form described by Matthew [1897b, p. 169] and have referred it as a variety (magna) of Acrotreta sagittalis (Salter) (p. 706) . Formation and locality. — Middle Cambrian: (2s) Limestone in upper part of Paradoxidcs zone, Hastings Cove [Matthew, 1898b, p. 38], on Kennebecasis Bay, 0.5 mile (O.S km.) northeast of Torryburn, on the Intercolonial Railway, northeast of St. John, St. John County, New Brunswick. Acrotreta idahoensis Walcott. Plate LXV, figures 1, la-i; Plate LXVIII, figures 2, 2a-g. Acrotreta attenuata Meek (in part), 1873, Sixth Ann. Rept. U. S. Geol. and Geog. Survey Terr, for 1872, p. 463, foot- note. (Among the specimens which Meek listed as ^. subconica and for which he proposed the name A. attenuata in a footnote are specimens which are now referred to A. idahoensis. See also A. attenuata and A. attenuata var.) Not Acrotreta subconica Kutorga, 1848, Verhandl. Russ.-kais. min. Gesell. St. Petersburg for 1847, No. 12, p. 275. (Referred in this monograph to Acrotreta s^ibconica.) Acrotreta idahoensis Walcott, 1902, Proc. U. S. Nat. Mus., vol. 25, p. 587. (Described essentially as below as a new species.) The general outline, form, and convexity of the two valves are so fully shown by the illus- trations that detailed descriptions will not be given. The material for illustrating the interior of the ventral valve is limited, but one cast shows the position of the base of the cast of the foraminal tube, and the large, main vascular sinuses (PL LXV, fig. Id). An interior of a dorsal valve and the accompanying cast (PI. LXV, figs. If, Ig) present characters rarely seen in this genus. The vascular canals arch out beyond the central muscle scars, and then bend in toward the median ridge, and again obliquely outward to form the outer limit of a smooth, polished, lanceolate-shaped surface that extends obhquely outward from the median ridge. The hne that extends from in front of the cardinal scars forward, subparallel to the margin of the shell, and then bends abruptly in and forward is apparently the outer boundary of a very broad. 688 CAMBRIAN BRACHIOPODA. shallow, vascular sinus. Something of this same character occurs in the dorsal valve of Oholus {Linguloiolus) spissus (Billings) (PI. XVI, figs. 2, 2cl). The cardinal scars are small and situated close to the narrow area. Another cast of the interior (fig. le) shows the central scars distinctly; also the presence of a thickening of the shell in the vicinity of the cardinal scars. The median ridge is smaller and shorter than in Plate LXV, figure Ig. Observations. — The external characters of this species suggest Acrotreta curvata Walcott, but the elevation and curvature of the ventral valve are not the same and the interior of the dorsal valve is very distinct in its specific characters. There are no interiors of the form from the Black Hills, but the external characters appear to be the same. These include the broad false area, with its shghtly marked groove, the position of the apex, and the curvature of the false area. Acrotreta idahoensis has been found in the Dunderberg shale of the Eureka district, Nevada, and it extends up also to the base of the Pogonip limestone. The horizon is higher than that of the type specimen, but the shells from the higher and lower horizons appear to be identical. Formation and locality. — Lower Ordovician: (201a) Pogonip limestone, east slope of the ridge east of Ham- burg Ridge; and (202) Pogonip limestone on the summit of the ridge directly southeast of the Jackson mine, north- west of Shadow Canyon; both in the Eureka district [Hague, 1892, Atlas], Eureka County, Nevada. Upper Cambrian: (61) Limestone in the Dunderberg shale [Walcott, 1908f, p. 184], a little south of the Hamburg mine. Eureka district [Hague, 1892, Atlas], Eureka County; and (313) limestone 0.75 mile (1.2 km.) east-northeast of McGill post office, WTiite Pine County; both in Nevada. (15d) Thin-bedded blue limestone near Gave Spring, on the east side of the Fish Spring Range, about 4 miles (6.4 km.) south of the J. J. Thomas ranch, Juab County; and (30h) about 350 feet (106.7 m.) above the Middle Cam- brian and 2,960 feet (899.2 m.) below the top of the Upper Cambrian, near the base of the arenaceous limestones form- ing 2a of the Orr formation [Walcott, 1908f, p. 177], on Orr Ridge, about 5 miles (8 km.) south of Marjum Pass, House Range [Walcott, 1908f, PI. XIII], Millard County; both in Utah. (5c and 54t) Limestones of the St.Charles formation [Walcott, 1908a, p. 6], about ^50 feet (76 m.) above the Middle Cambrian; and (54u) limestones of the St. Charles formation about 100 feet (30.2 m.) above the Middle Cambrian; both on the north side of Twomile Canyon near its mouth, 2 miles (3.2 km.) southeast of Malade, Oneida County, Idaho. (56g) Limestone of the St. Charles formation [Walcott, 1908a, p. 6], in the valley of the stream which flows into Mill Canyon from the west, about 6 miles (9.6 km.) west-southwest of Liberty and 15 miles (24.2 km.) west of Mont- pelier, Bear Lake County, Idaho. Middle Cambrian: (88a) Limestone about 100 feet (30.5 m.) above the quartzitic sandstone at the base of the Cambrian, in the northern suburbs of Deadwood; and (165) limestone on the east side of the valley, in raiboad cut about 1 mile (1.6 km.) below the main part of Deadwood; both in the Black Hills, South Dakota. (302a) Limestones at several places on the south side of the Gallatin Valley, Gallatin County, Montana. (302b) Limestones near Crowfoot Ridge, Gallatin quadrangle (U. S. Geol. Survey), Yellowstone National Park, Wyoming. (59g) Limestones immediately overlying the Spence shale member of the Ute limestone [Walcott, 1908a, p. 8], in a saddle north of the creek which flows into Mill Canyon from the west, about 5 miles (8 km.) west-southwest of Liberty and 15 miles (24.2 km.) west of Liberty, Bear Lake County, Idaho. (llo) About 2,750 feet (838.2 m.) above the Lower Cambrian and 1,650 feet (502.9 m.) below the Upper Cam- brian, at the base of la of the Marjum limestone [Walcott, 1908f, p. 179], about 4 miles (6.4 km.) southeast of Antelope Springs, in the spur at the junction of the Deseret and Swasey Spring roads [Walcott, 1908f, PL XIII], House Range, Millard County, Utah. Acrotreta cf. idahoensis. This species is represented by a single specimen of a somewhat imperfect ventral valve. It is larger than the average shells of Acrotreta idalioensis Walcott, and appears to have had a more incurved apex. The exterior layer is also duller and less distinctly striated than most specimens of the latter species. The shell is built up of numerous thin layers or lamellae, more or less obUque to the outer surface; the lamella are marked by numerous fine radiating striae and a few concentric strise. The general impression given by the shell is that it is an old shell which has thickened by growth and become more robust and incurved than is usual in the species with which it is compared. Formation and locality. — Middle Cambrian: (7j) Limestones at the north end of the Quinn Canyun Range, 1 mile (1.6 km.) northwest of the Italian Ranch foothills, Nye County, Nevada. ACKOTRETID.^. 689 ACEOTRETA IDAHOENSIS ALTA Walcott. Plate LXV, figures 4, 4a-b, Acrotreta gemma Walcott (in part) [not Billings], 1884, Mon. U. S. Geol, Survey, vol. 8, pp. 17-18, PI. I, figs, la and lb (not figs. lc-£; see below), and (?) PI. IX, figs. 9 and 9a (see also below). (Specimens now referred to Acrotreta attenuata, A. pyxidicula, and A. curvata were included ■\vith the specimens representing A. idahoensis alta when this description of A. gemma was written, A. curvata being figured, PI. I, figs. Id and le. The specimen represented by PI. I, fig. la, is redrawn in this monograph, PI. LXV, fig. 4a. Fig. Ic represented a specimen of Acrotreta sabring; the specimens represented b.y figs. If and 9 and 9a are missing.) Acrotreta gemma Walcott (in part) [not Billings], 1891, Tenth Ann. Rept. U. S. Geol. Survey, p. 608, PI. LXVII, figs. 5 and 5a (not figs. 5b-e; see below). (Figs. 5 and 5a are copied from figs, la and lb of preceding reference. Specimens now referred to Acrotreta attenuata, A. pyxidicula, A. curvata, and A. primxva were included with the specimens representing A. idahoensis alta in this reference to A. gemma, but only the last two were figured: A. curvata, PL LXVII, fig. 5b, and A. primxva, PL LXVII, figs. 5c, 5d, and 5e.) Acrotreta gemma Walcott, Hall and Clarke (in part) [not Billings], 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, p. 102, figs. 56 and 57 (not fig. 55). (Mentioned in the text, and figures copied from Walcott, 1884b, PI. I, figs, la and lb. The specimen represented by fig. 55 is referred in this monograph to Acrotreta curvata.) Acrotreta gemma Walcott (in part) [not Billings], 1899, Mon. U. S. Geol. Survey, vol. 32, pt. 2, p. 449, PL LXII, figs. 2a and 2c (not figs. 2, 2b, 2d, and 2e; see below). (Figs. 2a and 2c are copied from Walcott, 1884b, PI. I, figs, la and lb, respectively. Specimens now referred to Acrotreta attenuata, A. pyxidicula, A. curvata, and A. primxva were included with the specimens representmg A. idahoensis alta when this description of A. gemma . was written, but only the last two were figured: A. curvata, PL LXII, figs. 2e, and A. primxva, PI. LXII, figs. 2, 2b, and 2d.) Acrotreta idahoensis alta Walcott, 1902, Proc. U. S. Nat. Mus., vol. 25, p. 588. (Characterized essentially as below as a new variety.) Tlais is one of the forms that I included %vitli Acrotreta gemma Billings in the report on the Paleontology of the Eureka district, Nevada [lS84b, p. 17]. It has the broad .false area of A. idahoensis Walcott, but the ventral valve is more elevated and the apex does not over- hang the false area. From A. attenuata Meek it differs in having a broad false area. A form indistinguishable from Acrotreta idahoensis alta occurs in the Dunderberg shale of the Eureka district section of Nevada. The horizon is higlier than tliat of the type specimen, but there appears to be no way of distinguishing between the type and the Dunderberg shale specimens. A similar but smaller form extends up through from the Dunderberg shale into the arenaceous and calcareous shales at the base of the Pogonip hmestone, where fossds of the Ordovician fauna occur. This form owes its varietal name to its high ventral valve. Formation and locality. — Lower Ordovician: (63) At base of Pogonip limestone, northeast of Adams Hill, Eureka district [Hague, 1892, Atlas], Eureka County, Nevada. Passage beds between the Upper Cambrian and the Ordovician: (201) Arenaceous Pogonip limestone on east slope of ridge east of Hamburg Ridge; and (206a) sandy limestone on Hoosac Mountain; both in the Eureka district [Hague, 1892, Atlas], Eureka County, Nevada. Upper Cambrian: (61) Limestone in the Dunderberg shale [Walcott, 1908f, p. 184], a little south of the Hamburg mine ; and (65) limestone on the east side of Sierra Canyon, opposite Pinnacle Peak ; both in the Eureka district [Hague, 1892, Atlas], Eureka County, Nevada. (54f) 150 feet (45.7 m.) above the Middle Cambrian and 1,075 feet (327.7 m.) below the top of the Upper Cambrian in light-gray sandstone forming No. 4 of the St. Charles formation [Walcott, 1908f, p. 193], in Blacksmith Fork Canyon about 10 miles (16.1 km.) east of Hyrum, Cache County; (34q) shales about 3,800 feet (1,158.2 m.) above the Brigham quartzite [Walcott, 1908a, p. 8], in Wasatch Canyon, east of Lakeview ranch, about 5 miles (8 km.) north of Brigham, Boxelder County; and (15d) thin-bedded blue limestone near Cave Spring on the east side of the Fish Spring Range, about 4 miles (6.4 km.) south of the J. J. Thomas ranch, Juab County; all in Utah. Middle? Cambrian: (33n) Limestone pebbles, west front of the Pavant Mountains, at the mouth of Crow Creek, about 4 miles (6.4 km.) east of Fillmore, Millard County, Utah. Middle Cambrian : (58) Shaly liviestone in upper beds of Secret Canyon shale, east side of New York and Secret can- yons, Eureka district [Hague, 1892, Atlas], Eureka County, Nevada. (7i) Limestone just west of the summit on the road east of Schellbourne; and (313b) limestones 3 miles (4.8 km.) north-northeast of Schellbourne; both in the Schell Creek Range, WTiite Pine County, Nevada. (302w) Limestone at Madison Mountain, Montana. 62667°— vol 51, pt 1—12 44 690 CAMBKIAN BRACHIOPODA. ACROTRETA IDAHOENSIS SULCATA Walcott. Plate LXV, figure 5. Acrotreta idahoensis sulcata Walcott, 1902, Proc. U. S. Nat. Mus., vol. 25, p. 588. (Characterized as below as a new variety.) Tliis strongly marked ventral valve is associated with the variety alta, but in its rounded posterior side and strong median groove it is quite distinct. The apex is broken off so as to show the cast of a small apical callosity and the base of a minute forammal tube. This form owes its varietal name to the fact that it possesses a sulcate ventral valve. Formation and locality. — TTpper Cambrian: (301i) About 350 feet (106.7 m.) above the Middle Cambrian and 2,950 (899.2 m.) below the top of the Upper Cambrian, near the base of the arenaceous limestones forming 2a of the Orr formation [Walcott, 1908f, p. 177], on Orr Ridge, about 5 miles (8 km.) south of Marjum Pass, House Range [Wal- cott, 1908f, PI. XIII], Millard County, Utah. (54t) Limestone of the St. Charles formation [Walcott, 1908a, p. 6], about 250 feet (76 m.) above the Middle Cam- brian, on the north side of Twomile Canyon, near its mouth, 2 miles (3.2 km.) southeast of Malade, Oneida County, Idaho. Middle Cambrian: (54s) Dark blue-gray Langston limestone [Walcott, 1908f, p. 198], just above the Cambrian quartzitic sandstones, north side of Twomile Canyon, near its mouth, 2 miles (3.2 km.) southeast of Malade, Oneida County; (55c) Spence shale member of the Ute limestone [\^'alcott, 1908a, p. 8], about 50 feet (15.2 m.) above the Brigham quartzite and 2,755 feet (839.7 m.) below the Upper Cambrian, in a ravine running up into Danish Flat from Mill Canyon, about 6 miles (9.6 km.) west-southwest of Liberty and 15 miles (24.2 km.) west of Montpelier, Bear Lake County; and (322a) Langston limestone near Paris, Bear Lake County; all in Idaho. Acrotreta inchoans (Barrande). I Plate XV, figures 7, 7a. Lingula inchoans Barrande, 1868, Faune silurienne des environs de Hof, en Baviere, p. 102, figs. 74 and 75. (De- scribed in French as a new species; see below for translation. Figs. 74 and 75 are reproduced in this mono- graph, PI. XV, figs. 7 and 7a, respectively.) Lingula inchoans Barrande, 1868, Neues Jahrb. fiir Mineralogie for 1868, p. 692, unnumbered plate, figs. 74 and 75. (Copy of preceding reference.) Acrothele inchoans (Barrande), Pompeckj, 1896, Tremadoc Fossilien bei Hof, p. 3. (Discussed in German.) Acrothele inchoans (Barrande), Matthew, 1902, Bull. Nat. Hist. Soc. New Brunswick, vol. 4, pt. 5, No. 20, p. 404. (Mentioned.) Acrothele inchoans (Barrande), Matthew, 1903, Geol. Survey Canada, Rept. Cambrian Rocks Cape Breton, p. 103. (Copy of preceding reference.) The original description by Barrande follows: Under this name we unite several very small shells, rounded in appearance, but more or less elongated, which, however, might represent merely the youthful form of another species. These very flat shells show one or two con- centric grooves at the external contour. The one which is represented in figure 74 [PL XV, fig. 7, of this work] has, moreover, in the middle a faint longitudinal groove which extends nearly throughout its length. Dimensions: Length, 2 mm.; breadth, 3.2 mm. on the specimen in figure 74 [PI. XV, fig. 7, of this work]. Ohservations. — Pompeckj wrote me that he had concluded that this species was an Acrotreta and not a Lingula. The illustrations and descriptions of Barrande suggest that the specimens represent the compressed dorsal valves of Acrotreta. Matthew [190'2a, p. 404] places this species under Acrothele, but with only the figure given by Barrande I prefer to accept Pompeckj's provisional reference to Acrotreta. Formation and locality. — Passage beds between the ITpper Cambrian and the Ordovician: (303c [Barrande, 1868a, p. 102]) Dark argillaceous shale in the suburbs of Hof ; and (303f [Pompeckj, 1896a, pp. 7 and 8]) railway cut near Schellenberg, a little distance back of the railway station at Neuhof, near Hof; both in Bavaria, Germany. Acrotreta inflata (Matthew). Plate LXXVI, figures 1, la-k, 2, 2a. Lingulella? inflata Matthew, 1886, Trans. Roy. Soc. Canada for 1885, 1st ser., vol, 3, sec. 4, No. 4, p. 33, PL V, figs. 7 and 7a. (Discussed as a new species. The specimen represented by figs. 7 and 7a is redrawn in this mono- graph, PL LXXVI, fig. 2.) Lingulella? inflata Matthew, 1895, Trans. New York Acad. Sci. for 1894-95, vol. 14, p. 127, PL V, figs. 3a-b. (Men- tioned. Figures copied from preceding reference.) ACKOTRETID.^. 691 Lingulella? inflata ovalis Matthew, 1895, Trans. New York Acad. Sci. for 1894-95, vol. 14, p. 127, PI. V, figs. 4a-c. (Described and discussed as a new variety. The specimen represented by figs. 4a-c is redrawn in this mono- graph, PI. LXXVI, fig. 2a.) Lingulella? inflata Matthew, 1898, Trans. Roy. Soc. Canada for 1898, 2d ser., vol. 4, sec. 4, No. 2, p. 128. (Mentioned.) Acrothyra? inflata Mattkevt , 1901, Bull. Nat. Hist. Soc. New Brunswick, vol. 4, pt. 4, No. 19, p. 304. (Merely suggests change in generic reference.) Lingulella {Acrothyra?) inflata Matthew, 1902, idem, vol. 4, pt. 5, No. 20, p. 390. (Mentioned.) Acrotreta inflata (Matthew), Walcott, 1902, Proc. U. S. Nat. Mus., vol. 25, pp. 588-589. (Described essentially as below.) Shell subcircular to transversely broad oval. Ventral valve subcorneal, with the apex directed backward and usuallj' on a line with the posterior margin, or extending bej'ond it (PL LXXVI, figs. 1' and la'), but it nxa.j be anterior to it (PI. LXXVI, figs, lb' and Id'); false area slightly defined by the abrupt curvature of the cardinal slopes, median line depressed, narrow, the two sides of tlie false area incurving to form it (PL LXXVI, fig. Ig) ; pedicle aperture longitudinally oval and slighth^ truncating the apex. Dorsal valve gentlj- convex, with a minute marginal beak. Surface of shell marked by concentric strise and growth lines, and fine, irregular, wavy striae that inosculate more or less, giving the surface a fretted appear- ance under a strong lens. The inner surface is marked by concentric lines and rather strong radiating lines. The shell is built up of a thin outer ornamented surface and several thin inner la}rers or lamellis. The average length of the ventral valve is 4 mm. and the width 3 to 3.5 mm. The dorsal valves are usually wider than long. Casts of the interior of the ventral valve show strong cardinal scars, a strong apical callosity, and rather weakly developed main vascular sinuses. The apical callosity varies in size and in form from elongate oval (PL LXXVI, fig. lb) to subcuTular (fig. If). The cast of the interior of the dorsal valve shows large cardinal muscle scars, and a broad, short median ridge posteriorly that extends beyond the center of the valve. Ohservations. — This species appears to be a true Acrotreta with the apical callosity elon- gated by the elongation of the ventral valve. The dorsal valve is more convex than in most species of Acrotreta, which gives a stronger relief to the ridges on the cast between the cardinal scars and the median ridge. The posterior view (PL LXXVI, fig. Ik') should be compared with the same view of the dorsal valve of Acrotreta sagittalis (Salter) and its varieties (PL LXXI, figs. 11', Im', and 3g"; and PL LXXII, figs, le' and If). The fretted surface is of the same type as that of several other species of the genus. Matthew had very little material when he described the species [1886, p. 33]; subsequently [1895a, p. 127] he created the variety ovalis fi'om a more elongated ventral valve. In the col- lection made for the United States National Museum by Loper, there are a number of ventral and dorsal valves. The range of variation in outline appears to cover the variety ovalis. Some are more transverse than the original type of the species and others nearlj^ as elongate as the variety ovalis. I have therefore considered the variety as within the original species. Some of the shells show elongation and others are broadened by distortion. Matthew [1895a, p. 127] called attention to the resemblance of this species to Linnarssonia and Acrotreta, and when describing the genus Acrothyra suggested [1901b, p. 304] that it miglat belong to that genus. It appears, however, to be a true Acrotreta. A series of specimens, sup- plemented hj the types and a number of ventral valves received from Doctor Matthew which he had [1895a, p. 126] provisionally identified as '^Acrotreta gemma Bilhngs?" show a rather remarkable variation in outline and position of the apex of the ventral valve. This is illus- trated by the figures on Plate LXXVI, also by a number of specimens not illustrated. The narrow forms, var. ovalis Matthew, have the apex extended beyond the posterior margin, and in the broad forms the apex is above or in advance of the posterior margin, but if the shells are compressed vertically the apex may be pushed out over the false area whether the shell be narrow or broad. I think that in the normal form the false area is vertical or slightly inclined backward. Formation and locality. — Middle Cambrian: (2f and 2g)a Sandstones of DiA-ision Ibl of Matthew's [1895a, p. 108] Protolenus zone, Hanford Brook, St. John County, New Brunswick, Canada. a The specimens in the United States National Museum collections to which these numbers are assigned were collected at the type locality but later than the type specimens. 692 CMIBRIAN BRACHIOPODA. ACROTKETA KUTORGAI Walcott. Text figure 58; Plate LXV, figures 3, 3a-e, 3g-k. Acrotreta kutorgai Walcott (in part), 1902, Proc. U. S. Nat. Mus., vol. 25, pp. 589-590. (Described as a new species, but owing to a different interpretation of the structural characters of the ventral valve the description differs from the one given below. Specimens now referred to Acrotreta rudis were included with true representatives of A. kutorgai in this description.) The external characters of the ventral valve are clearly exhibited (PI. LXV) bv figures 3, 3a, and 3d, and what is known of the interior by figures 3b and 3c. Figure 3g is that of a most interesting specimen, as it clearly shows the cast of the cardinal area of the dorsal valve adjusted against the false area and pseudodeltidium of the ventral valve. In 1902 (p. 589) I considered this cast of the cardinal area of the dorsal valve to be the true area and pseudo- deltidium of the ventral valve, and figure 3g was drawn to bring out this interpretation. Figure 58 represents a view into the interior of the cast, showing the cast of the false area and pseiidodeltidium of the ventral valve, as well as the cast of the cardinal area of the dorsal valve. The cardinal area of the dorsal valve is well defined in the casts represented by Plate LXV, figures 3h-j. The median ridge of the dorsal valve is as long proportionally as that of A. hisecta, and like it varies in length and size in different shells. The outer surface is marked by fine concentric striae -1 and lines of growth. Observations. — This pretty species occurs attached to the surface of siliceous nodules in association with riGUKE 5s.-Acrotrcia kutorgai Walcott. View into QUnoides curticei, Crepicepliolus texauus, Acrothele iellula interior, the specimen being tipped, as shown in the .^ i ,, i , p ■^ r i rrii xt j: ii side outline. A vertical view of the same specimen Walcott, and CastS of Mcdusse. ilie OUthne ot the COn- is sho%™ in Plate LXV, figure 3g. vexity of the valvcs and the posterior view of the ventral The specimen represented is from Localit^^^^^^^^ ^ j^ ^^^^^ j-j.^ ^^^.^^ ^f j^ ^Hg^Uata Meek, but the Coosa Valley, Alabama(U. S.Nat. Mus. Cat. No. 3o2i(a;. ... interior markings are quite unlike. The specific name was given in honor of Kutorga. Formation and locality. — Upper Cambrian: (361) Shaly limestone in suburb of Attalla, Etowah County, Alabama. (107o and 107u) Limestones and shales at the base of the Knox dolomite, west of the top of Copper Ridge, near the Southern Railway cut, about 10 miles (16.1 km.) northwest of Knoxville [Keith, lS96b, areal geology sheet], Knox Count}', Tennessee. Middle Cambrian: (90b) Conasauga limestone in cut on Louisville and Nashville Railroad, near Woodstock, Bibb County; (90) Conasauga ("Coosa") shale on Edwards farm, near Craigs Mountain, about 10 miles (16.1 km.) southeast of Center, Cherokee County; (140) limestone interbedded in shales near Chepultepec, Blount County; (90x) in and attached to the outer surface of siliceous nodules in the Conasauga {"Coosa") shale, Coosa Valley, Cherokee County; (137) shales on the southeast side of the northeast end of the Cane Creek Mountains, 3 miles (4.8 km.) south of Gadsden, Etowah County; and (139a) limestones on road near Wades Gap, near Chepultepec, Blount County; all in Alabama. Specimens that are somewhat doubtfully referred to this species occur at the following localities: Middle Cambrian: (142) Shales just above the Olenellus zone, near the railroad, 4.5 miles (7.2 km.) north of Montevallo, Shelby County, Alabama. (18) Limestone 1 mile (1.6 km.) east of Gap Creek, 13 miles (20.8 km.) S. 75° E. of Knoxville, Knox County, Tennessee. Acrotreta lisaxi Walcott. Plate LXVI 11, figures 3, 3a-c. Acrotreta liani Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 300. (Described and discussed as below as a new species. Li San's name was at that time believed to be correctly written as Lian, hence the form of the specific name.) Shell small, about 1.5 mm. in diameter; outline of aperture subcircular, the posterior side being sli2:htly transverse. Ventral valve conical, with the apex a little in advance of ACROTKETID^. 693 the posterior margin; false area indefinite, except for a rather strong, shallow furrow that extends from the apex to the margin. The elevation of the valve is about two-tliirds its diameter at its aperture. Dorsal valve slightly convex, apex marginal. Surface of shell marked by fine, concentric striae and lines of growth that on the dorsal valve tend to form low ridges toward the outer margms. Observations. — This species is the representative of the American Acrotreta idahoensis sulcata Walcott. It has the same type of false area, and the ventral valve is of average height. The specific name is given in recognition of Li San, Mr. Wilhs's faithful Chinese interpreter. Formation and locality. — Middle Cambrian: (C22i Changhia limestone in upper oolitic portion [Blackwelder, 1907a, pp. 22 and 33 (part of last list of fossils)], at Changhia, Shantung, China. Acrotreta marjumensis Walcott. Plate LXXVIII, figures 2, 2a-d. Acrotreta marjumensis Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, pp.. 94-9.5, PI. IX, figs. 2 and 2a. (De- scribed and discussed as below as a new species. Figs. 2 and 2a are copied in this monograph, PL LXXVIII, figs. 2 and 2c, respectively.) The general form of this species is much like that of Acrotreta idahoensis Walcott. Tlie ventral valve differs in having a more strongly marked and broader false area and in the greater cui'vature of the apex over the false area. It is also less elevated, or convex, in pro- portion to the size of the shell. It may also be compared with A. nehoensis Walcott, from which it differs in being less elevated and in not having a well-indicated false pedicle furrow. The dorsal valve is moderately convex and difl'ers little from the dorsal valve of A. idahoensis and A. nehoensis. The interior of the dorsal valve shows a narrow median ridge that, at the center and toward the front of the shell, rises as a sharp, rather high, and very narrow ridge.. This ridge starts posteriorly from a subtriangular, somewhat elevated area which has a longitudinal furrow crossing it. The cardinal and central muscle scars are very clearly defined; in some cases the central scars are sHghtly depressed, and in other shells elevated above the general surface of the interior of the shell. The specific name is derived from Marjum Pass, near the tj^pe locality. Formation and locality. — Upper Cambrian: (33d) Thin-bedded blue limestone at the base of the first high point southwest of the J. J. Thomas ranch, on the east side of the Fish Spring Range, Juab County, Utah. Middle Cambrian : (lln) About 3,000 feet {914-4 m.) above the Lower Cambrian and 1,400 feet {4^6.7 m.)' below the Upper Cambrian, in the upper part of the limestone forming la of the Marjum limestone [Walcott, 1908f, p. 179], in the long cliff 2 miles {3.2 km.) southeast of Marjum Pass, House Range [Walcott, IQOSf, Pis. XIII and XV\, Millard County, Utah. Acrotreta microscopica (Shumard). Plate LXVII, figures 1, la-h, lo, 2, 2a-d. Disdna microscopica Shumard, 1861, Am. Jour. ScL, 2d ser., vol. 32, p. 221. (Described as a new species.) The external outline, form, and convexity of the two valves are so fully illustrated by the figures that I will only call attention to the variation in the outline of the elevation of the ventral valve. In Plate LXVII, figure Id", the false area slopes backward instead of forward as in other specimens. The lines of growth show that the growth of the anterior portion of the shell was much more rapid than on the posterior face, thus causing the apex to tip back toward the area, a feature not observed in the other specimens illustrated. The concentric surface striae are sharp, but very fine. The only interior of a ventral valve found is represented by figures lo, lo', and lo". The typical forms from Texas are representad by Plate LXVII, figures 1, la-h, and lo, and what appears to be an identical form from Nevada by figures 2, 2a-d. The latter form shows about the same range of variation in outline and position of the apex of the ventral valve as the typical foirms from Texas. This species belongs to the group of forms with a wide false area. It differs from A. idahoensis Walcott and A. curvata Walcott in the form of the ventral valve. 694 CAMBEIAN BRACHIOPODA. Acrotreta microscopica has remained without iUustration for manj^ years. I made a large collection in Burnet County, Texas, in 1884, which was increased by Coope/ Curtice in 1890. We found the little shell in great numbers associated with characteristic Upper Cambrian fossils. In the Eureka district, Nevada, there is a small species of Acrotreta, which, so far as can be determined from the material available for study, is identical with the A. microscopica as it occurs in the Upper Cambrian limestones of Texas. It has essentially the same range of varia- tion in the fomi of the ventral valve, and the dorsal valves also appear to be identical. (Com- pare figs. 1 and 2a (the latter has been broadened by pressure); figs. Id' and 2'; and the side outlines la and 2c; and lb" and 2b.) The ventral valves have the same outline and convexity. The outhnes of the convexity of figures le-g should be more nearly as in figures Ih and 2d and not concavo-convex as shown on the plate. Formation and locality. — Upper Cambrian: (67) Sandstone on Tatur Hill, 7 miles (11.2 'km.) northwest of Burnet, Bui-net County; and (70e) limestone near Morgans Creek, Burnet County; (69) limestone near Honey Creek, Bui-net County; (71) limestone in Cold Creek Canyon, Burnet County; (68 and 68e) limestone in Packsaddle Mountain, Llano County; (14b) limestone on Cold Creek at north end of gorge opposite the north end of Sponge Mountain, 2 miles (3.2 km.) south of the San Saba County line, in Llano County; (14g) limestone 1 mile (1.6 km.) west of Cherokee, San Saba County; and (14e) limestone in Bartlett Hollow, 2 miles (3.2 km.) southeast of the mouth of Falls Creek, Burnet quadrangle (U. S. Geol. Survey), Lampasas County; all in Texas. (12p) About 225 feet (69 m.) above the igneous rocks, in the limestones of the Reagan sandstone, at the northwest extremity of the Arbuckle Mountains, about 4 miles (6.4 km.) east of Homer, Carter County; (12n) limestones of the Beagan sandstone (in the section 7 miles (11.2 km.) north of Springer this horizon is about240 feet (73m.) above the porphyry contact and 40 feet (12 m.) below the Arbuckle limestone), NW. i sec. 1, T. 2 S., R. 1 E., Ardmore quad- rangle, Carter County; (12k) limestones of the Reagan sandstone (in the section 7 miles (11.2 km.) north of Springer this horizon is about 225 feet (69 m.) above the porphyry contact and 55 feet (17 m.) below the Arbuckle limestone), on the west side of Honey Creek, near the southeast corner of sec. 35, T. 1 S., R. 1 E., Ardmore quadrangle (U. S. Geol. Survey), Carter County; and (9r and 9t) about 45 feet (14 m.) and 170 feet (52 m.), respectively, above the por- phyry contact in the limestones of the Reagan sandstone, SE. i NE. i sec. 2, T. 4 N., R. 13 W., 15 miles (24.2 km.) northwest of Fort Sill, Comanche County; all in Oklahoma. Tipper? Cambrian: (8o) Limestone on the slope of the ridge where the range swings around to the northwest, 2 miles (3.2 km.) north of Aurum, Schell Creek Range, White Pine County, Nevada. Middle Cambrian: (58) Shaly limestones in upper beds of Secret Canyon shale, east side of New York and Secret canyons, Eureka district [Hague, 1892, Atlas], Eureka County, Nevada. ACKOTRET.\ MICROSCOPICA MISSOURIENSIS Walcott. Plate LXVII, figures 4, 4a-b. Acrotreta microscopica missouriensis Walcott, 1902, Proc. U. S. Nat. Mus., vol. 25, p. 590. (Described as below as a new variety.) The shell is uniformly larger and the vertical median line of the false area more depressed, incurved, and distinct than those of Acrotreta microscopica (Shumard) and the variety tetort/- ensis Walcott. Some of the specimens of the ventral valves beautifully illustrate the effects of compression. One shell (PI. LXVII, figs. 4' and 4") is Hke that of Acrotreta attenuata Meek and the other (PL LXVII, figs. 4a and 4a') resembles the low form of A. ophirensis Walcott with the apex overhanging the false area. The surface of the shells embedded in the fine-grained sandstone has a papillose surface resulting from the indenting of the shell by the grains of sand, whereas those from limestone are marked only by fine concentric striae. Formation and locality.— Middle Cambrian: (Ilk) Sandstones of the "Edgewise beds," beneath the Elvins forma- tion, St. Francois County; and (lie) thin-bedded limestones south-southwest of Potosi, Washington county; both in Missouri. Acrotreta microscopica tetonensis Walcott. Plate LXVII, figures 3, 3a-d. Acrotreta microscopica tetonensis Walcott, 1902, Proc. U. S. Nat. Mus., vol. 25, p. 590. (Characterized as below as a new variety.) This neat little shell possesses the characters of Acrotreta microscopica (Shumard) and A. idahoensis Walcott^ but differs from both by the projection of the apex of the ventral valve ACROTEETIDiE. 695 over the false area. All that is known of it is represented by the illustrations (PL LXVII, figs. 3, 3a-d). The varietal name is derived from the Teton Mountains, Wyoming. Formation and locality. — Middle Cambrian: (4e) Limestones about 950 feet (289.6 m.) above the uncon- formable base of the Cambrian in the divide at the head of Jackson Creek (locally known as Sheep Creek), a creek flowing into Jackson Lake about 0.5 mile (0.8 km.) south of its northwestern comer, Teton Mountains, Grand Teton quadrangle (U. S. GeoL Survey), Uinta County, Wyoming. AcROTRETA? MINIMA (Barrande). Plate LXXVII, figures 7, 7a. Obolus? minimus Baerande, 1879, Systeme silurien du centre de la Boheme, vol. 5, pt. 1, PI. XCV, figs, ii: 1-5. (Not described, but figured as a new species. Figs. 3A and lA are reproduced in this monograph, PL LXXVII, figs. 7 and 7a, respectively.) This minute shell may possibly belong with Acrothele, but with the data furnished by the illustrations of Barrande [1879b, PI. XCV, figs. ii:l-5] a provisional reference is made to Acrotreta. It certainly is not an Oholus. The figures illustrate all the characters known. Formation and locality. — Lower Ordovician: (303d [Barrande, 1879b, PL XCV]) Etage dl, Swarow, Bohemia, Austria-Hungary. Acrotreta misera (Billings). Plate LXXII, figures 2, 2a-l. Obolellaf miser Billings, 1872, Canadian Naturalist, 2d ser., vol. 6, No. 4, pp. 470-^71. (Described and discussed.) Obolella ? miser Billings, 1874, Geol. Survey Canada, Paleozoic Fossils, vol. 2, pt. 1, p. 69. (Copy of preceding refer- ence.) Linnarssonia misera (Billings), Matthew, 1886, Trans. Koy. Soc. Canada for 1885, 1st ser., vol. 3, sec. 4, No. 4, pp. 35-36, PL V, figs. 12, 12a-e. (Described and discussed.) Linnarssonia misera (Billings), Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, pp. 108-109, PL III, figs. 35-37. (Mentioned. Figs. 35 and 36 are drawn from the specimens figured by Matthew, 1886, PL V, figs. 12c and 12, respectively.) Acrotreta miser (Billings), Walcott, 1902, Proc. U. S. Nat. Mus., vol. 25, pp. 590-591. (Described essentially as below.) The abundant material representing this species that I collected in Newfoundland gives illustrations that present its characters with such fullness and detail that minute description is unnecessary. Plate LXXII, figures 2, 2a-e of the ventral valve, show variation in outline, also of the cast of the apical callosity, cardinal scars, and base of main vascular sinuses. Figures 2h-l illustrate the interior of the dorsal valve. The outer surface is marked by fine concentric striae and growth lines, and the inner layers or lamellae by very fine radiating striae. The minute pedicle aperture is on the back side of the apex, opening almost posteriorly in some examples. This is a small species, averaging from 1.5 to 2.5 mm. in length. Formation and locality. — Middle Cambrian: (1 and 2) Shales of zones A and B, respectively, of No. 7 of the Manuels Brook section [Walcott, 1891b, p. 261], Manuels Brook, Conception Bay; (314 [Billings, 1872h, p. 470]) Paradoxides zone on Chappie Arm, Trinity Bay; (314h) shale on Manuels Brook, Conception Bay; (6g) limestone near the base of the Middle Cambrian, northwest side of Chappie Arm Harbor, about 1 mile (1.6 km.) from its head. Trinity Bay; (6h) limestone in the southwest cove of Chappie Arm, Trinity Bay; and (6r) limestone on the west side of Manuels Brook, Conception Bay; all in Newfoundland. (2s and 2t) Shales and interbedded limestones in the upper part of the Paradoxides zone, Hastings Cove [Matthew, 1898b, p. 38], on Kennebecasis Bay, 0.5 mile (0.8 km.) northeast of Torryburn, on the Intercolonial Railway, north- east of St. John; and (3011 [Matthew, 1886, p. 36]) shale of Division Id of Matthew, on Porters Brook, St. Martins; both in St. John County, New Brunswick, Canada. Acrotreta neboensis Walcott. Plate LXXVII, figures 9, 9a-b. Acrotreta neboensis Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 300-301. (Described as below as a new species.) Ventral valve moderately elevated, the apex projecting slightly over the nearly vertical false area. The latter is marked midway by a very narrow false pedicle furrow. The transverse 696 CAMBRIAN BRACHIOPODA. dorsal valve has a strong median depression which starts on the umbo and widens out rapidly toward the front. The surface of the shell is marked by concentric ridges and lines of growth and very fine concentric strise. Observations. — This is one of the Acrotreta idahoensis forms of the genus. It differs from other described forms in the strong median depression of the dorsal valve. The specific name is derived from Mount Nebo Canyon, the type locality. Formation and locality. — Middle Cambrian: (14t) Limestone lying on slope between the Cambrian quartzite and the massive blue limestone 100 feet ^30.5 m.) above, in Mount Nebo Canyon, 3 miles (4.8 km.) southeast of Mona, Juab County, Utah. Acrotreta nicholsoni Davidson. Plate LXXIII, figures 1, la-k, 6, 6a-b. Acrotreta? nicholsoni Davidson, 1868, Geol. Mag., vol. 5, pp. 313-314, PI. XVI, figs. 14^16. (Described and discussed as a new species; see below for copy of description. Figs. 14, 15, and 16 are reproduced in this monograph, PI. LXXIII, figs. 1, Ic, and Id, respectively.) Acrotreta ? nicholsoni Davidson, 1871, British Fossil Brachiopoda, vol. 3, pt. 7, No. 4, pp. 343-344, PI. XLIX, figs. 36-40. (Described and discussed. Figs. 36, 37, and 40 are copied from figs. 15, 14, and 16, respectively, of the preceding reference. Figs. 38 and 39 are reprofluced in this monograph, PL LXXIII, figs, la and lb, respectively.) Aa-otreta nicholsoni Davidson, Swanston, 1877, Proc. Belfast Natiualists' Field Club, Appendix 4 for 1876-77, PL VII, figs. 21a-c. (Not described. Figs. 21b and 21c are copied from Davidson, 1868, PL XVI, figs. 14a and 14b.) Acrotreta nicholsoni Davidson, 1883, British Fossil Brachiopoda, vol. 5, pt. 2, p. 213, PL XVI, figs. 21-23. (New localities mentioned and new figures given. Figs. 21a, 21c, 21b, 22a, 22b, 21d, and 22c are reproduced in this monograph, PL -LXXIII, figs, le-lk, respectively.) Acrotreta nicholsoni Davidson, Sw.^-Nston, 1886, Systematic Lists, Flora, Fauna, Paleontology, and Archaeology, North of Ireland, vol. 1, PL VII, figs. 21a-c. (Reprint of Swanston, 1877, PI. VII, figs. 21a-c.) Acrotreta nicholsoni Davidson, Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, p. 103, fig. 59. (Mentioned in the text and fig. 59 copied from Davidson, 1868, PL XVI, fig. 16a.) The original description by Davidson follows: Shell small, about 2 lines in length by about the same in breadth, almost cii'cular; rather wider and broadly rounded anteriorly; nearly straight posteriorly; dorsal valve very slightly convex; ventral valve conical; apex subcentral and truncated by a minute circular foramen, situated at a little more than bne-thii-d of the length of the valve. From the center of the posterior margin a narrow groove or channel extends to the base of the foramen, while on either side a small, flattened triangular space or false area (?) is limited by an indented line. Sm-face of both valves marked with numerous concentric lines of growth. Subsequently Davidson obtained some less-compressed specimens and reiUustrated [1883, PI. XVI, figs. 21-2,3] the species. In order to bring before the student all available information I have reproduced most of Davidson's figures. Oiservations. — A. nicholsoni is one of the largest species of the genus and one of the latest in point of time. Davidson [1883, PI. XVI, figs. 21-23] illustrates specimens 5 to 6 mm. in length, and it ranges up into the Llandeilo. The strongly marked false area and the high ventral valve serve to distinguish this species. The specific name was given in honor of Nicholson. Formation and locality. — Lower Ordovlcian: (316 [Davidson, 1871, p. 34S]) Upper Llandeilo (?) hlach shales, at Dobbs Linn, near Moffat, Dumfriesshire; and (316a [Davidson, 1883, p. 213]) Llandeilo at Craighead, Ardmillan Brae, and Balcletchie, all in the Gu'van district of Ayrshire; both in Scotland. (317 [Davidson, 1883, p. 213]) Coalpit Bay, County Down, Ireland. Upper Cambrian: (304:h) Shineton shales at Mary Dingle, South Shropshire; and (SOla [Groom, 1902, p. 110]) "Bronsil" shales, Malvern Hills; both in England. Acrotreta nox Walcott. Plate LXXVII, figure 10. Acrotreta nox Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 301. (Characterized as below as a new species.) This minute shell, 1 mm. in length, is characterized by its low ventral valve, nipple-hke apex, and apparently smooth surface. Formation and locality. — Upper Cambrian : (lOv) Shales in "St. Croix sandstone, " at Fox Glen, 8 miles (12.8 km.) east of Baraboo, Sauk County, Wisconsin. ACROTRETID^. 697 AcROTRETA CELANDiCA Westergard. Acrotreta oelandica WestergIrd, 1909, Medd. fran Lunds Geol. Faltklubb, Ser. B, No. 4 (Aftryck m- K. Fysiografiska Sallskapets Handl., N. F., Bd. 20), p. 76, PI. V, figs. 24a-b. (Described in Swedish as a new species; see below for translation.) The original description by Westergard follows: Apex situated near the posterior border. Along the latter there is a faintly defined triangular area which occupies one-fourth of the periphery of the shell. The shell is about half as high as broad. Surface smooth, with fine distinct gi-owth lines, which, although more faintly, are also to be seen on the area. The slope fi-om the apex to the anterior border is slightly concave, though this is likely a secondary phenomenon due to pressure. The apes itself has not been preserved. Formation and locality. — Upper Cambrian: (310r) Zone v. of the Ceratopyge slate at Ottenby, Oeland Island; and (310s) uppermost part of the alum slate in beds equivalent to the Ceratopyge slate, northern -part of Oeland Island; both [Westergard, 1909, p. 76] in Sweden. Acrotreta ophirensis Walcott. Plate LXXIV, figures 1, la-p. Acrotreta ophirensis Walcott, 1902, Proc. U. S. Nat. Mus., vol. 25, pp. 591-592. (Described as below as a new species.) General outline transversely broad oval, sometimes nearly circular, with the posterior margin shghtty indented midway on the ventral valve by incurving to the false pedicle furrow. The ventral valve is convex and moderately elevated, the highest point being in front of the pedicle aperture at about one-tliird the diameter of the shell. Pedicle aperture large for the size of the shell and opening either directly or obKquely backward; one specimen shows an obscure, short, narrow, triangular false area, with a vertical furrow crossing it (PI. LXXIV, fig. la"); false area scarcely defined by the cardinal slopes, which incurve very gently ; median furrow well defined, rather strong, and nearly flat on the bottom, the margins being sharply outlined in many specimens. Some of the shells curve over the false area so that the depressed apex extends sHghtly beyond the posterior margin, but generally it is directly on the fine of, or a little in front of, the posterior margin. Longitudinal diameter of average size ventral valve 3 mm., wdth a length of 2 to 2.5 mm.; elevation, 1.5 mm. A few shells have nearly the same length and ^\adth. The convexity of the dorsal valve averages 0.75 mm. The minute beak of the dorsal valve curves down to the posterior margin from the somewhat swollen posterior third of the valve. Surface marked by fine concentric striae and lines of growth, some of which form con- centric ridges. The shell is built up of a thin outer layer and numerous thin inner layers or lamellae that are oblique to the outer layer over the central and outer portions, the obUquity increasing toward the outer anterior and lateral margins. The interior of the ventral valVe shows a rather strong apical callosity that extended nearly to the posterior inner margin of the shell; distinct, but relatively small cardinal scars, and narrow main vascular sinuses that ma}^ be traced nearly to the anterolateral margins of the valve. The outlines of the visceral cavity are indicated on one well-preserved cast of the interior of the valve (PI. LXXIV, fig. le). The interior of the dorsal valve shows great varia- tion in the size and length of the median ridge and cardinal and central scars; these characters are fuUy shown in the numerous illustrations of the interior and casts of the interior of the dorsal valve. Observations. — This species is most closely related to Acrotreta curvata Walcott. It differs in the ventral valve being larger, in the apex being less extended over the false area, and the form of the median furrow, which is Hke that of A. attenuata Meek. Although the shells occur in a compact unaltered hnaestone, there is more or less distortion in the outline of both valves; this, taken in connection mth the variation in form and size of the vascular markings, muscle scars, and median ridge of the dorsal valve, might serve to discriminate several so-called varie- ties, but I have given names to only two of the more pronounced varieties. 698 CALIBEIAN BRAOHIOPODA. Similar forms occur in a compact, dark, bluish-gray limestone more than 200 miles to the north in the Wasatch Mountains, east of Cache Valley, on the line of the Ute Peak section of the Fortieth Parallel Survey. The specific name is derived from Ophir, the type locality. Formation and locality. — Middle Cambrian: (3e) Limestone less than 400 feet {121.9 m.) above the quartzitic sandstones of the Cambrian, at Ophir, Oquirrh Range, Tooele County, Utah. (30n) About 3,750 feet (1,143 m.) above the Lower Cambrian and 650 feet (198 m.) below the Upper Cambrian, in the shaly limestones forming Ic of the Weeks limestone [Walcott, 1908f, p. 175], on the north side of Weeks Canyon, about 4 miles (6.4 km.) south of Marjum Pass; (30g) about 2,350 feet (716.3 m.) above the Lower Cambrian and 2,050 . feet (624. S m. ) below the Upper Cambrian in the limestone forming Ic of the Marjum limestone; and (3x and 3y) about 2.200 feet (670.6 m.) above the Lower Cambrian and 2,200 feet (670.6 m.) below the Upper Cambrian in the shaly lime- stones forming Id of the Marjum limestone [Walcott, IQOSf, p. 180], in the ridge east of A\lieeler Amphitheater; all in the House Range [Walcott, 1908f, Pi. XIII], Millard County, Utah. (31z and 55t) About 350 feet (106.7 m.) above the Brigham quartzite in limestone of the Ute limestone [Walcott, 1908f, p. 7], on west side of road, 0.5 mile (0.8 km.) above the forks. Paradise Dry Canyon (locally known as East Fork), east of Paradise, Cache County, Utah. ACROTEETA cf. OPHIRENSIS Walcott. Numerous compressed specimens of shells about the size of Acrotreta opMrensis Walcott occur in strata of Middle Cambrian age at various localities in Utah. They resemble the latter species in size, occasional strong lines of growth, position of the apex of the ventral valve, and strong cardinal muscle scars in the dorsal valve; they differ in being much less convex, and in having only a trace of shell substance; the removal of the shell by solution and the compression in the shale accounts very largely for the differences. The stratigrapliic position of the two forms is about the same and they both Uved in the eastern portion of the CordiUeran Middle Cambrian Sea. Formation and locality.— Middle Cambrian: (32j) 625 feet (190.5 m.) above the top of the Cambrian quartzitic sandstone in pinkish-colored very fine grained arenaceous shale, 2 miles (3.2 km.) southeast of Muskrat Spring, on the northwest face of Grantsville Peak, Stansbury Range, Tooele County, Utah. (31v) 650 feet (198.1 m.) above the Lower Cambrian and 3,750 feet (1,143 m.) below the Upper Cambrian, in shales at the top of the limestone forming la of the Howell formation [Walcott, 1908f, p. 182], northeast side of Dome Canyon, about 4 miles (6.4 m.) west-southwest of Antelope Springs; (lly and 30g) about 2,350 feet (716.3 m.) above the Lower Cambrian and 2,050 feet (624.8 m.) below the Upper Cambrian in Ic of the Marjum limestone fWalcott, 1908f, p. 180], ridge east of \\Tieeler Amphitheater; and (31s) 490 feet (149.4 m.) above the Lower Cambrian and 3,925 feet (1,196.3 m.) below the Upper Cambrian, in the pinkish argillaceous shale forming Id of the Howell formation fWalcott, 1908f, p. 182], south side of Dome Canyon about 1 mile (1.6 km.) below the divide, and 3 miles (4.8 km.) west-southwest of Antelope Springs; all in the House Range [Walcott, 190Sf, Pis. XIII and XVI], MUlard County, Utah. (31c) About 900 feet (274.3 m.) above the Brigham quartzite and 3.300 feet (1,005.8 m.) below the Upper Cam- brian, in the limestone forming lb of the Ute limestone [Walcott, 1908f, p. 196], in Blacksmith Fork Canyon, about 10 miles (16.1 km.) east of Hyrum, Cache County; (32c) about 60 feet (18.3 m.) above the Brigham quartzite [Walcott, 1908a, p. 8], in green shale, 1 mile (1.6 km.) northwest of Geneva (Copenhagen), east of Brigham, Boxelder County; and (30u) about 250 feet (76.2 m.) above the Cambrian quartzitic sandstones in sandy shales, 4 miles (6.4 km.) northwest of Promontory Point (on the "Lucin cut-off" of the Union Pacific Railway), about halfway up west end of ridge, north of Great Salt Lake, Boxelder County; all in Utah. Acrotreta ophirensis descendbns Walcott. Plate LXXVIII, figures 1, la-c. Acrotreta ophirensis descendens Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, p. 95, PI. IX, figs. 1 and la. (Discussed as below as a new variety. Figs. 1 and la are copied in this monograph, PI. LXXVIII, figs. 1 and Ic, respectively.) In the Cambrian section of the House Range, Utah, the typical forms of Acrotreta opMr- ensis occur in the Marjum limestone; 1,570 feet higher in the section, in the Weeks limestone, there are great numbers of a shell identical in many respects. This latter shell differs from the typical form in being less convex in both the ventral and dorsal valves, and in having a more pointed, less curved apex on the ventral valve. ACROTRETID^. 699 This form owes its varietal name to the fact that it occurs higher in the section than the species, and is probably descendant from it. Formation and locality. — Middle Cambrian: (30n) About 3,750 feet (1,143 m.) above the Lower Cambrian and 650 feet (198 m.) below the Upper Cambrian in. shaly limestones forming Ic of the Weeks limestone [Walcott, 1908f, p. 175], on the north side of Weeks Canyon, about 4 miles (6.4 km.) south of Marjum Pass, House Range [Walcott, 1908f, PL XIII], Millard County, Utah. ACEOTRETA OPHIEENSIS RUGOSA Walcott. Plate LXXIV, figures 2, 2a-e. Acrotreta ophirensis rugosus Walcott, 1902, Proc. U. S. Nat. Mus., vol. 25, p. 592. (Characterized as below as a new variety.) This form is associated with Acrotreta opTiirensis Walcott in considerable numbers. It is characterized by strong, rugose growth lines and thicker shell. FoRM.ATioN .^ND LOCALITY. — Middle Cambrian: (3e) Thin-bedded limestone, less than 400 feet (121.9 m.) above the quartzitic sandstones of the Cambrian, at Ophh, Oquii-rh Range, Tooele County, Utah. Acrotreta ovalis Walcott. Plate LXVI, figures 2, 2a-b. Acrotreta ovalis Walcott, 1902, Proc. U. S. Nat. Mus., vol. 25, p. 592. (Characterized as below as a new species.) In material received from the Geological Survey of Canada in answer to a request for the specimens representing Acrotreta gemma Bilhngs, there was one ventral valve embedded in a smooth, dove-colored limestone from Point Levis. This specimen differs materially from A. gemma in the oval outline of the rim of the shell, less elevated apex, and less well-defined false area. It is more of the type of A. schmalenseei Walcott, and of A. microscopica (Shumard) of the interior continental species than any of the Atlantic Province forms. Formation and locality. — Lower Ordovlcian: (319 [Geol. Survey, Canada]) Limestone No. 1 of Billings's Point Xievis Section, Point Levis, Province of Queljec, Canada. Acrotreta pacifica Walcott. Plate LXIX, figures 6, 6a-e. Acrotreta pacifica Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 301. (Described below as a new species.) Ventral valve a high cone, with the apex a little in advance of the posterior margin; base circular, with the exception of a slight flattening on the posterior side ; apex acute and pointing upward; false area only a slight flattening of the shell from the apex to the margin. The largest ventral valve has a diameter and height of about 1.5 mm. Surface marked by fuie concentric striee that continue without noticeable deflection across the false area. OhservatioTis. — Only two specimens of the ventral valve of tliis species occur in the collec- tion. One of these has a slightly transverse, broadly oval base, and a more definite false area. The species is closely related to Acrotreta idaJioensis alta Walcott except that the ventral valve is not quite as elevated. Formation and locality. — Middle Cambrian: (CI and C2) Lower shale member of the Kiulung group [Black- welder, 1907a, pp. 37 and 40 (part of the 3d list of fossils) and fig. 10 (beds 4 and 5), p. 38], 2 miles (3.2 km.) south of Yenchuang; (C12) gray limestone near the top of the middle limestone member of the Kiulung group [Blackwelder, 1907a, pp. 37 and 41 (part of the fii'st list of fossils) and fig. 10 (bed 7), p. 38], 3.25 miles (5.2 km.) southwest of Yen- chuang; (C6) lower limestone member of the Kiulung group [Blackwelder, 1907a, pp. 37 and 39 (first list of fossils), and fig. 8a (bed 30), p. 29], 3.2 miles {5.1 km.) southwest of Yenchuang; and (C4) limestone nodules at the base of the lower shale member of the Kiulung group [Blackwelder, 1907a, pp. 37 and 40 (2d list of fossils), and fig. 10 (bed 4), p. 38], -■3 miles (4.8 km.) southwest of Yenchuang; all in the Eintai district. Shantung, China. Acrotreta parvula (Wallerius). Plate LXXVII, figures 4, 4a. ■Obolella parvula Wallerius, 1895, UndersQkningar ofver Zonen med Agnostus Isevigatus i Vestergotland, pp. 65-66, figs. 9ii-d. (Described in Latin, and discussed in Swedish.) Acrotreta parvula (Wallerius), Walcott, 1902, Proc. U. S. Nat. Mus., vol. 25, p. 592. (Described as on p. 700.) 700 CMIBRIAN BRACHIOPODA. Shell minute, subcircular. Ventral valve relatively depressed, the highest point being at the umbo, from which there is a slight downwartl curvature to the apex. False area low and about vertical, the apex being on a line with the posterior margin. Dorsal valve slightly convex; beak marginal. Surface marked by fine concentric strise. Obsen'ations. — This minute species occurs with Agnostus Isevigatus in the upper portion of the j\Iiddle Cambrian. It is of the Acrotreta sagittalis (Salter) type, but does not appear to be identical with the young of that species. Formation and locality. — Middle-Upper Cambrian : (310i) Passage beds between the Middle Cambrian Para- doxides forchhanuneri zone and the Upper Cambrian Olenus truncatus zone, limestone at Borgholm, Oeland Island, Sweden. Middle Cambrian: (320) Gudhem, 12.5 miles (20.1 km.) south-southeast of Skara; and (320a) Djupadal, 19 miles {30.6 hm.) south-southeast of Shara; both [Wallerius, 1895, p. 66] in the Province of Skaraborg, Sweden. ACEOTEETA PEIMiEVA Walcott. Plate LXIX, figures 1, la-f. Acrotreta gemma Walcott (in part) [not Billings], 1886, Bull. U. S. Geol. Survey No. 30, pp. 98-99, PI. VIII, figs. 1, la-b. (Specimens now referred to Acrotreta pyxidicula and A. attenuata were included with the specimens representing A. primseva when this description of A. gemma was written, but they were not figured. The two specimens represented by figs, lb and 1, la are redrawn in this monograph, PL LXIX, figs. Ic and 1, respectively.) Acrotreta gemma Walcott (in part) [not Billings], 1891, Tenth Ann. Kept. U. S. Geol. Survey, p. 608, PI. LXVII, figs. 5c, 5d, and 5e (not figs. 5, 5a-b, see below). (Figs. 5c, 5d, and 5e are copied from figs, la, 1, and lb, respec- tively, of preceding reference. Specimens now referred to Acrotreta attenuata, A. idahoensis alta, and A. curvata were included with the specimens representing A. primseva in this reference to A. gemma, but only the last two were figured: A. idahoensis alta, PI. LXVII, figs. 5 and 5a, and A. curvata, PI. LXVII, fig. 5b.) Acrotreta gemma Walcott (in part) [not Billings], 1899, Mon. U. S. Geol. Survey, vol. 32, pt. 2, p. 449, PI. LXII, figs. 2, 2b, and 2d (not figs. 2a, 2c, and 2e, see below). (Figs. 2, 2b, and 2d are copied from Walcott, 1886b, PL VIII, figs. 1, la, and lb, respectively. Specimens now referred to Acrotreta pyxidicula, A. attenuata, A. idahoensis alta, and A. curvata were included with the specimens representing A. primseva when this description oi A. gemma was written, but only the last two were figured; A. idahoensis alta, PL LXII, figs. 2a and 2c, and A, curvata, PL LXII, fig. 2e.) Acrotreta primasea Walcott, 1902, Proc. U. S. Nat. Mus., vol. 25, p. 593. (Described essentially as below as a new species.) Acrotreta gemma Walcott, Geaeau and Shimer [not Billings], 1907, North American Index Fossils, vol. 1, p. 199, figs. 234a-c. (Described, and figures copied from Walcott [1886b, PL VIII] figs, la, 1, and lb, respectively.) Outline of valves transversely oval to subcircular. Ventral valve subconical, with the apex at the summit of the false area near or just above the posterior margin. The elevation varies from one-half to two-thirds the diameter of the shell. The false area is quite clearly defined in most specimens; it varies in width at the posterior margin from one-third to nearly one-half of the diameter of the shell; the path of advance of the pseudodeltidium is marked usually by a narrow incised line similar to that of Acrotreta attenuata Meek. Foraminal aper- ture minute and situated at the apex of the cone. Dorsal valve shghtly convex, with a minute beak slightly incurved over the posterior margin. A broad, slightly defined median sinus flattens the front and central portion of the valve, but it is not perceptible toward the umbo and beak. Surface of the shell marked hj fine concentric striae and occasional ridges of growtli; on some shells there is a very fine, almost microscopic, irregular, concentric striation that gives a fretted surface somewhat similar to that of Oholus (Westonia) ella (Hall and Whitfield). The inner lamellae of the shell and tlie interior surface have traces of fine radiating striae that, with the irregular concentric striae, give a broken, subimbricated, fretted effect to the surface. The shell is formed of a thin outer layer and several thin inner layers or lamellae, the outer ones of which are slightly oblique to the outer surface layer. The largest shells have a transverse diameter of 5.5 mm., longitudinal diameter 5 mm., height of ventral valve 3 mm.; dorsal valve 1 mm. The interior of a slightly crushed ventral valve, figure le, shows the cast of an apical callosity, strong vascular canals, and faint outlines of the visceral cavity. The cast of an interior of a dorsal valve has a long, well-defined median ridge, cardinal scars, and faintly defined central scars, as illustrated by figures Id and If. Interiors of the ventral valve from near ACEOTRETID.^. 701 Cherry Creek show two relatively small cardinal scars near the posterior margin, and a small sub triangular apical callosity. Ohservafions. — This, the oldest species of the genus known to me, has all the essential characters of the type species as far as the available information permits of comparison. It is one of the largest shells of the genus, and is a striking feature of the fauna of the liigher portion of the Olenellus zone of central Nevada. The most nearly related species appears to be A. attenuata Meek (PI. LXIV, fig. 1). FoKMATioN AND LOCALITY.— Middle Cambrian: (7j) Limestones at the north end of the Quinn .Canyon Range, 1 mile (1.6 km.) northwest of the Italian Ranch foothills, Nye County, Nevada. Lower Cambrian: (41) Limestone in the Pioche formation [Walcott, 1908a, p. 11] on a ridge 2.5 miles (4 km.) northwest of the town of Cherry Creek, \Miite Pine County; and (31a) limestone and interbedded siliceous shales of the Pioche formation [Walcott, 1908a, p. 11], just above the quartzite on the east side of the anticline, near Pioche, Lincoln County; both in Nevada. ACROTEETA PYXDDICULA White. Plate LXIX, figures 2, 2a-f, 3, 3a-f. Acrotreta pyxidicula White, 1874, U. S. Geog. Surveys W, 100th Mer., Prelim. Rept. Invertebrate Fossils, p. 9. (Described as a new species.) Acrotreta pyxidicula White, 1877, U. S. Geog. Sm-veys W. 100th Mer., vol. 4, pt. 1, pp. 53-54, PI. Ill, figs. 3a-d. (Described essentially as in preceding reference. The specimens represented by figs. 3a-b and 3c-d are redrawn in this monograph, PL LXIX, figs. 2 and 2f, respectively.) Acrotreta gemma Walcott (in part) [not Billings], 1884, Mon. U. S. Geol. Survey, vol. 8, pp. 17-18. (Specimens representing Acrotreta attenuata, A. curvata, and A. idahoensis alta were included with the specimens representing A. pyxidicula when this description of A. gemma was written, but only the last two are known to have been figured: A. curvata, PL I, figs. Id and le, and A. idahoensis alta, PL I, figs, la and lb. The specimens repre- sented on PL IX, figs. 9 and 9a, can not be positively located at this time, but it is probable that they should be referred to A. idahoensis alta.) Acrotreta gemma Walcott (in part) [not Billengs], 1886, Bull. U. S. Geol. Survey No. 30, pp. 98-99. (Specimens now referred to Acrotreta attenuata and A. primxva were included with the specimens representing A. pyxidicula when this description of A. gemma was written, A. primxva being figiu-ed, PL VIII, figs. 1, la-b.) Acrotreta gemma Walcott (in part) [not Billings], 1891, Tenth Ann. Rept. U. S. Geol. Survey, p. 608. (Specimens now refeiTed to Acrotreta attenuata, A. curvata, A. idahoensis alta, and A. primxva were included with the speci- mens representing A. pyxidicula in this reference to A. gemma, the last three being figured: A. curvata, PL LXVII, fig. 5b; A. idahoensis alta, PL .LXVII, figs. 5 and 5a; and A. primxva, PL LXVII, figs. 5c, 5d, and 5e.) Acrotreta gemma Walcott (in part) [not Billings],' 1899, Mon. U. S. Geol. Survey, vol. 82, pt. 2, p. 449. (Specimens now refen-ed to Acrotreta attenuata, A. curvata, A. idahoensis alta, and A. primxva were included with the speci- mens representing A. ;;?/xJrficitta when this description of ^1. i/emma was written, the last three being figm-ed : A. curvata, PL LXII, fig. 2e; A. idahoensis alta, PL LXII, figs. 2a and 2c; and A. primxva, PL LXII, figs. 2, 2b, and 2d.) This is a small and very pretty species in which the interiors of the two valves are fairly well shown by casts. A marked feature of the ventral valve is the very strong vascular sinus (fig. 3f), and of the dorsal valve the thickening of the shell in the posterior portion (fig. 3e). The surface of the sheh is marked bj' fine concentric striae and occasional lines of growth. It is one of the small species of the genus, the average size being from 1.5 to 2 mm. Of the known species it may be compared with A. idaJioensis Walcott (PI. LXV) from which it differs in the shghter elevation of its ventral valve and the incised median line on the false area. FoEMATiON AND LOCALITY. — TTppei Cambrian: (313f) Limestone at Schellbourne, Schell Creek Range, White Pine County, Nevada. (329d) Limestone near Fish Springs, Fish Spring Range, Juab County, Utah. Middle Cambrian: (7j) Limestone at the north end of the Quinn Canyon Range, 1 mile (1.6 km.) northwest of the Italian Ranch foothills, Nye County; and (60) limestone in upper beds of Secret Canyon shale, across the canyon from the dump of the old Richmond mine shaft, Eureka district [Hague, 1892, Atlas], Eureka County; all in Nevada. (30z) About 2,450 feet (746.8 m.) above the Lower Cambrian and 1,950 feet (594.4 m.) below the tapper Cambrian, in the upper part of the limestone forming Ic of the Marjum limestone [Walcott, 1908f, p. 180], in the long cliff about 2 miles (3.2 km.) southeast of Marjum Pass, House Range [Walcott, 1908f, pis. XIII and XV], Millard County, Utah. (5b and 54s) Dark blue-gray Langston limestone [Walcott, 1908f, p. 198], just above the Cambrian quartzitic sand- stones, north side of TwomUe Canyon, near its mouth, 2 miles (3.2 km.) southeast of Malade, Oneida County; (59f) limestones immediately underlying the Spence shale member of the Ute limestone [Walcott, 1908a, p. 8], in a saddle 702 CAMBRIAN BRACHIOPODA. north of the creek which flows into Mill Canyon from the west, about. 5 miles (8 km.) west-southwest of Liberty and 15 miles (24.2 km.) west of Montpelier, Bear Lake County; and (322) limestone (stratigraphic position unknown) about 6 miles (9.6 km.) west-southwest of Liberty and 15 miles (24.2 km.) west of Montpelier, Bear Lake County; all in Idaho. (4h) About 375 feet (114.3 m.) above the base of the Cambrian in the limestone interbedded in the Flathead shales of Peale [1893, p. 21], 1 mUe (1.6 km.) north of the junction of East Gallatin and West Gallatin (Gallatin) rivers, 4 miles (6.4 km.) east-northeast of Logan, Threeforks quadrangle (U. S. Geol. Survey), Gallatin County, Montana. ACEOTRETA EIIDIS Walcott. Plate LXV, figure 3f ; Plate LXXV, figure 1. Acrotreta hutorgai Walcott (in part), 1902, Proc. U. S. Nat. Mus., vol. 25, pp. 589-590. (Described as a new species, but the description included specimens belonging to both Acrotreta kutorgai and A. rudis.) Acrotreta rudis Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, pp. 95-96, PL IX, fig. 5. (Described and dis- cussed as below as a new species. Fig. 5 is copied in this monograph, PI. LXV, fig. 3f.) The specimens illustrating this species are all more or less crushed and flattened on the surface of the fine argillaceous shale in which they are embedded in large numbers, and they are often in the condition of casts of the interior of the valves. This is well shown by the enlargement of a fragment of the shale on which three ventral and three dorsal valves occur (PI. LXXV, fig. 1). The ventral valve, as far as can now be determined, was elevated, conical, and with the apex overhanging the false area, so that when the shells were crushed down the posterior side disappeared beneath. A few fragmentary specimens show the false area to have been distinctly defuied, of medium height, and marked by a narrow, shallow median furrow extending from the apex to the margin of the valve. Dorsal valve subcircular, slightly transverse, gently convex, and with a minute beak at the posterior margin. The pedicle opening appears to have been of medium size and situated at the apex of the valve. Surface marked by lines of growth and very fine concentric striae that continue across the false area and fiu-row. The cast of the interior of the ventral valve shows a small but well-defined visceral area in advance of the apex and a short strong main vascular sinus on each side of the area; one cast shows traces of the sinuses nearly to the front margin. The interior of the dorsal valve is marked by a strong median septum or ridge that extends from the front of a small cardinal area forward nearly to the anterior margin in some examples. A large, oval cardinal muscle scar occurs on each side of the median ridge near the posterior border of the valve; the central muscle scars are small, elongate oval and situated on the sides of the median ridge at about the posterior third of the longitudinal axis of the shell; the two anterolateral muscle scars are on the sides of the median ridge a little in advance of the central scars. Tliis is one of the large species of the genus. A dorsal valve 4 mm. in length has a width of 4.5 mm. The ventral valves average from 4 to 4.5 mm. from the apex to the front margin. In size and outline this species may be compared with Acrotreta depressa (PI. LXVT, figs. 8, 8a-c) and A. definita (PL LXIV, figs. 2, 2a-g). It differs from both in its ventral valve being more elongate. All the specimens of A. rudis are so flattened in the shale that com- parison with uncompressed specimens is very difficult. Formation and locality. — Middle Cambrian: (101a) Rogersville shale, just above the road in the hill loest of the Bchoolhouse, 3.5 miles {5.6 km.) .southwest of Rogersville on the road to Melinda Ferry [Keith, 1896a, areal geology sheet]; (102c) first shale south of the Estillville pike, 3.5 miles (5.6 km.) east of Rogersville, GreenevUle quadrangle (U. S. Geol. Survey); and (121) Rogersville shale, road just east of Harlan Knob, 4 miles (6.4 km.) northeast of Rogersville [Keith, 1905, areal geology sheet]; all in Hawkins County, Tennessee. AcEOTEETA SABEiNJE (Callaway). Plate LXXIII, figures 5, 5a-d. Metoptoma sahrinae Callaway, 1874, Quart. Jour. Geol. 'Soc. London, vol. 30, pt. 1, p. 196. (Name proposed, not described.) Obolella sabrinse Callaway, 1877, idem, vol. 33, pt. 1, p. 669, PL XXIV, fig. 12. (Described as a new species. The specimen represented by fig. 12 is redrawn in this monograph, PL LXXIII, fig. 5b.) ACROTRETID^. 703 Oholella sahrinse (Callaway), Davidson, 1883, British Fossil Brachiopoda, vol. 5, pt. 2, p. 211, PI. XYI, figs. 27, 27a, 27d, 28, and 2Sa. (Described and discussed.) Oholella? scabrims (Callaway), Walcott, 1884, Mon. U. S. Geol. Survey, vol. 8, PL I, fig, Ic. (Not described, and figiu-e copied from Davidson, 1883, PL XVI, fig. 27d.) Oholella sahrinse (Callaway), Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, p. 103, fig. 58. (Mentioned in the text and figure copied from Davidson, 1883, PL XVI, fig. 27d.) Acrotreta sp. of. nichohoni Davidson, Matley, 1902, Quart. Jour. Geol. Soc. London, vol. 58, pt. 1, p. 142, fig. 10. (Discussed in text as Acrotreta sp., and figured as A. sp. cf. nichohoni.) Acrotreta {?) sahrinse (Callaway), JIatlet, 1902, idem, p. 143. (Discussed.) Acrotreta (f) sahrinse malvernensis Matley, 1902, idem, pp. 143-144, figs. 11-14. (Described and discussed as a new variety.) Acrotreta sp. cf. A. socialis von Seebach, Matley, 1902, idem, pp. 144-145, figs. 15 and 16. (Characterized and dis- cussed.) As in the case of most species of Acrotreta preserved in shales, the Yentral valves of this form are so compressed as to prevent our getting the true elevation. With several fairly well- preserved specimens to judge from I think the height was about two-thirds of the greatest diam- eter of the shell. A partial cast of the interior shows a small apical callosity and the base of the cast of a small pedicle tube. The interior of the dorsal valve is almost bisected by a strong median ridge; the cardinal scars are also prominent. A fragment of the outer shell shows fine, concentric striae and Hnes of growth that are fretted by very fine undulating striae. Through the courtesy of Dr. Charles Lapworth I have had the opportimity of studjnng and illustrating the type specimen of Callaway's "Oholella sahrinse" (PI. LXXIII, fig. 5b). It is a cast of the dorsal valve preserving little more than the impression of the strong median ridge and a trace of the area. Dr. Lapworth also sent me several other specimens of this species; these are illustrated on Plate LXXIII, figures 5, 5a, 5c, and 5d. Davidson [1883, PI. XVI, fig. 27d] illustrates an interior of a dorsal valve in which the median ridge and the cardinal and central scars are clearly defined. He also gives [1883, PI. XVI, figs. 27, 27a] the exterior of a compressed ventral valve and a side view of the two valves imited. Of described species, Acrotreta hisecta Matthew approaches this most closely. It is qmte probable that with a good series of specimens of each species for comparison the two forms would be referred to the one species of Callaway. Matley [1902, p. 143, figs. 11-14] illustrates and describes some crushed specimens from the lowest black shales of the ilalvern HiUs, which he tentatively gives the value of a variety of this species under the name malvernensis. With examples from the typical locaHt}'' before me for comparison %\'ith the proposed variety, I am inclined to consider the latter of such doubtful value as to leave it out of tliis work. He also [Matley, 1902, p. 144] mentions an Acrotreta as sp. cf. A. socialis von Seebach from a higher stratigraphic horizon. Acrotreta socialis as now restricted is confined to the ^Middle Cambrian. I do not tliink that the material as illustrated and described by Matley clearly indicates a form distinct from Acrotreta sahrinss, if allowance is made for the crushed condition of naost specimens of the latter species. The shell mentioned as Acrotreta sp. cf. nicTiolsoni [Matley, 1902, p. 142] may also be a large specimen of this species. The shells figxired by Matley [1902, p. 141, figs. 7 and 8] as Lingulella (?) sp. and [1902, p. 142, fig. 10] as Lingula {?) sp. I think are either Acrotreta or Acrothyra, probabty the latter. Formation and locahty.^ — Upper Cambrian : ( 304h and 304i [Callaway, 1877, p. 669]) Shineton shale, at Shineton, Mary Dingle, Dryton, Cressage, 1 mile (1.6 km.) west of Cressage, west of Harley, and under Cound-Moor quarry, all in South Shropshire, England. (304:p) Shineton shales at the following localities of the Geological Survey of Great Britain: 2495, 2536, 2543, 2545, 2558, and 2580, all of which are on Shineton Brook, South Shropshire, England. (304j) Lower Stockingford shales, Puxley Park lane, halfway up the path to the quarry, Atherstone, Warwick- shire; (304a [Groom, 1902, p. 110]) "Bronsil" shales, Malvern Hills; and (304b [Groom, 1902, p. 109]) lower part of the "White Leaved Oak" shales (the zone of Polyphyma), Malvern Hills; all in England. a Localities 304h and 304j are the only localities represented in the United States National Museum collections. 304h is the type locality. 704 CMIBRIAN BRACHIOPODA. ACEOTRETA SAGITTALIS (Salter). Plate LXXI, figures 2, 2a-h, 3, 3a-j. •Obolella sagittalis Salter, 1866, Rept. British Assoc. Adv. Sci. for 1865, p. 285. (Name proposed.; Discina labiosa Salter, 1866, idem, p. 285. (Name proposed.) Obolella sagillalis Salter, Davidson, 1868, Geol. Mag., vol. 5, pp. 309-310, PI. XV, figs. 17-24. (Described and dis- cussed.) Obolella sagittalis Salter, Davidson, 1871, British Fossil Brachiopoda, vol. 3, pt. 7, No. 4, pp. 339-340, PI. L, figs. 1-14. (Copy of preceding reference. Figs, la, 3a, 4 and 4a, 5 and 5a, 9, 10 and 10a, and 12 and 12a appeared, Da-\ddson, 1868, PI. XV, as figs. 17a, 21a, 23 and 23a, 19 and 19a, 22a, 20 and 20a, and 24 and 24a, respectively.) Obolella sagittalis Salter, Linnarsson, 1876, Bihang till K. svensk. Vet.-Akad. Handl., Bd. 3, No. 12, pp. 19-20, PI. Ill, figs. 36-41. (Described and discussed in English.) Obolella sagillalis Salter, Linnarsson, 1879, Sveriges Geol. Undersokning, Afhandl. och Uppsatser, Ser. C, No. 35, pp. 27-28, PI, III, figs. 45-49. (Described in Swedish.) Obolella sagittalis Salter, Brogger, 1882, Die silurischen Etagen 2 und 3, p. 45, PI. X, figs. 6-8. (Described and discussed in German.) Obolella sagittalis Salter, Davidson, 1883, British Fossil Brachiopoda, vol. 5, pt. 2, p. 211, PI. XVI, figs. 25-26. (Gives new localities and new figures.) Linnarssonia sagittalis (Salter), Walcott, 1885, Am. Jour. Sci., 3d ser., vol. 29, p. 115, figs. 5 and 8. (Merely refers the species to Linnarssonia. Figs. 5 and 8 are copied from Davidson', 1868, PI. XV, figs. 22a and 23a, respec- tively.) Obolella ida ? Dawson, 1888, Canadian Rec. Sci., vol. 3, p. 55. (Possible occurrence discussed.) Obolella ida f Dawson, 1888, Peter Redpath Museum, Montreal, Canada; Notes on Specimens, April, 1888, p. 55. Obolella (Linnarssonia) pretiosa Dawson, 1890, Trans. Roy. Soc. Canada' for 1889, 1st ser., vol. 7, sec. 4, No. 3, pp. 53-54, figs. ■26a-c. (Discussed.) Linnarssonia cf. pretiosa Dawson, Hall, 1890, idem, p. 55. (Description of the specimens discussed in preceding reference.) Linnarssonia sagittalis (Salter), Walcott, 1891, Tenth Ann. Rept. U. S. Geol. Survey, PL LXVIII, figs. 2a-d. (Not described.) Linnarssonia pretiosa (Dawson), Hall and Clarke, 1892, Nat. Hist., New York, Paleontology, vol. 8, pt. 1, p. 70, PL III, figs. 43-44. (Discussed. Figs. 43-44 are copied from Dawson, 1890, figs. 26a-c, p. 53.) Linnarssonia sagittalis (Salter), Hall and Clarke, 1892, idem, p. 108, figs. 60-61. (Discussed. The figures are copied from Da-\ddson, 1868, PL XV, figs. 22a and 23a, respectively.) Linnarssonia pretiosa (Dawson), Schuchert (in part), 1897, Bull. U. S. Geol. Survey No. 87, p. 262. (Mere reference, but includes specimens now referred to both Acrothele pretiosa and Acrotreta sagittalis.) Linnarssonia sagittalis (Salter), Frech, 1897, additional plates inserted in 1897 in Lethaea geognostica, pt. 1, Lethsea palseozoica, Atlas, 1876, PL lA, fig. 3a. (No text reference. Fig. 3a is copied from Walcott, 1891a, PL LXVIII, fig. 2. ) Obolella cf. sagittalis Salter, Wiman, 1902, Bull. Geol. Inst. Univ. Upsala, vol. 6, pt. 1, No. 11, p. 66. (New localities mentioned.) Obolella (Acrotreta '?) sagittalis (Salter), Moberg and Segerberg, 1906, Medd. fran Lunds Geol. Faltklubb, Ser. B, No. 2 (Aftryck ur K. Fysiografiska Sallskapets Handl., N. F., Bd. 17), p. 64, PL I, figs. 25 and 26. (Charac- terized in Swedish.) ^Linnarssonia pretiosa Grabau and Shimer, 1907, North American Index Fossils, vol. 1, p. 200. (Described, but not figured, and it is impossible to tell whether the authors are discussing the L. pretiosa that is now referred to Acrotreta sagittalis, or the true Acrothele pretiosa.) Although I have examined a large collection of this species, both from Wales and Sweden, good exteriors of the valves have not been observed. The apex of the ventral valve almost invariably remains in the matrix, or the shell has been removed by solution. The convexitj^ of the two valves is approximately the same (figs. 3c and 3d, PI. LXXI) except that the ventral valve is more elevated near the apex. The apex is situated a little in front of the posterior margin at the edge of the slightly defined false area which slopes forward at an angle of 70° to 80°. The surface of the shell is marked by rather strong concentric striae and often strong ridges of growth and very fine radiating striae on the interior layers. The shell is built up of thin la^^ers or lamellae of a calcareocorneous nature. The average diameter of specimens from St. Davids, Wales, is 2.5 mm. The representatives of the species from Andrarum, Sweden, are usually smaller than the St. Davids shells but other^vise appear to be identical. The interior of the ventral valve is shown bj^ numerous casts. The apical callosity and the cardinal scars are usually large. The visceral cavity is sometimes outlined in front of the callosity and between the clearly marked main vascular sinuses. Casts of the interior of the ACROTKETID.E. 705 dorsal valve show a remarkable range of variation in the length and size of the median ridge (PI. LXXI, figs. 3e, 3g-j). Within the extremes of variation specific characters could be established. This species has had a varied experience at the hands of paleontologists. Davidson [1871, PL L, figs. 1-14] elaborately illustrated the casts of the interiors of the valves, and I [1885, p. 116] copied some of his figures when preparmg the description of the genus Linnarssonia. When in Wales m 1888, 1 collected a quantity of material at St. Davids, and recently Schmalensee collected a good series at A:idrarum for the United States National Museum. From these col- lections figures have been drawn that illustrate the appearance of the sheUs as they occur both in shale and hmestone. The varieties taconica and transversa are strongly marked, but I think are not entitled to full specific valuation. A direct comparison of specimens from the black shales of Little Metis with those from the black shales of the type locality of A. sagittalis at St. Davids fails to. disclose any specific differences between them, so far as the material at hand permits of comparison. The Little Metis shell was published as Linnarssonia cf. pretiosa by Hall [1890, p. 55], and this identification was accepted by Su- William Dawson [1890, p. 53]. "Obolella pretiosa" Billmgs [1862d, p. 68] is a true Acrothele, and no species of Acrotreta is known to occur at the type locality on the Chaudiere River. The stratigraphic horizon of the Little Metis beds has not been definitely determined. Dawson [1890, p. 32] says: "At Metis the evidence of the pebbles in the conglomerates indicates that they are newer than the Lower Cambrian, and the few fossils found in the sandstones and shales would tend to place them at or on the horizon of «£he Chazy." I personally examined the section at Little Metis in 1899, and am not at all certain of the horizon of the shales carrying Acrotreta sagittalis and the beautiful fossil sponges described by Dawson [1890, pp. 37-55]. It is a region of strong folding and thrust faults. The Acrothele is a Middle Cambrian type, and nothing similar to it is known from the Upper Cambrian. As far as tins shell can locate the horizon, it is Cambrian, and probably low down in the Upper Cambrian, if not in the Mddle Cambrian. Formation and locality.— Passage beds between the Upper Cambrian and the Ordovician: (309 pioberg and Segerberg, 1906, desc. of PL I]) Ceratopyge limestone (Zone 4) at Fogelsang, 5 miles (8 km.) east of Lund, Province of Malmohus, Sweden. (323 [Wiman, 1902, p. 66]) Phyllograptus slate and Ceratopyge limestone in the Chi-istiania region of Norway; and (323h [Brogger, 1882, p. 17]) blue Ceratopyge limestone at Vestfossen, 10 miles (16.1 km.) west-southwest of Chi-istiania, Norway. Upper Cambrian: (321e-321m [IViman, 1902, p. 68]) Drift bowlders of Ceratopyge slate, Nos. 1-4, 6-8, 9, 12, 14, 17, 23, and 27, on Biludden, about 20 miles (32.2 km.) east of Gefle, Province of Gefleborg; and (321n [IViman, 1902, p. 68]) drift bowlder of limestone {Ceratopyge slate horizon), at Trodje, in Gastrikland; both in Sweden. (323a [Wiman, 1902, p. 66]) Ceratopyge slate in the Christiania region of Norway. (318g [Davidson, 1868, p. 310]) Lower Lingula flags at Porth-y-rhatv, Pen-y-pleidiau, and several other localities near St. Davids, South Wales. (318c [Davidson, 1868, p. 310]) Lower Lingula flags at the Rheider Waterfall Valley and at Gwynfynydd and other places near Dolgelly, all in North Wales. Middle? Cambrian (Probalily between Middle and Upper Cambrian); (392g [Dawson, 1888a, p. 55]) Black shales at Little Metis, Province of Queljec, Canada. Middle Cambrian: (2g) Sandstone of Division Ibl of Matthew's [1895a, p. 108] Protolenus zone on Hanford Brook, St. John County; and (2s) limestone in upper part of Paradoxides zone, Hastings Cove [Matthew, 1898b, p. 38], on Kennebecasis Bay, 0.5 mile (0.8 km.) northeast of Tonybm-n, on the Intercolonial Railway northeast of St. John, St. John County; both in New Brunswick. (6g) Limestone near the base of the Middle Cambrian, the lowest horizon caiTying Paradoxides, northwest side of Chappie Arm Harbor, about 1 mile (1.6 km.) from its head, Ti'inity Bay; (6w) limestone at Seal Point Cove, near Long Point, Trinity Bay; and (61) limestone about 300 feet (91.4 m.) below the base of the Upper Cambrian on shore north of Fosters Point, Random Island, Random Sound; all three in Newfoimdland. (3181i) Shales in the Menevian at St. Davids, South Wales. (316b [Davidson, 1883, p. 211]) Cairn Bum and Druidhill Bum, both in Dumfriesshire, Scotland. (8w) Limestones of the Paradoxides forchhammeri zone, at Andrarum, 20 mOes (32.2 km.) northwest of Simi-istamn, Province of Christianstad ; (321y) shale at Andrarum, 20 miles (32.2 km.) northwest of Simrishamn, Christianstad ; and (321z) shales at Fogelsang, 5 miles (8 km.) east of Limd, Province of MaLmohus; aU in Sweden. 62667°— VOL 51, pt 1—12 45 706 CAilBRIAN BRACHIOPODA. (lel) Limestones of the Paradoxides davidis zone at Borregaard; (16i) limestones of the Conocoryphe exsulans zone at Borregaard; (16j) limestones of the Paradoxides forchhammeri zone at Laesaa; (I6I1 and 3341i) limestones of the Paradoxides forchhammeri zone at Borregaard; and (16k) limestones of the Paradoxides davidis zone at LaesaS,; all on Bornholm Island, Denmark. Specimens somewhat doubtfully compared with Acrotreta sagittalis occur at the following localit}' : Middle Cambrian: (317a [Davidson, 1871, p. 340]) at Bellewstown, County Meath; and at Balbriggan, County- Dublin; both in Ireland. Acrotreta cf. sagittalis. High up in the Middle Cambrian of the House Range, Utah, there is a small, depressed species of Acrotreta that appears to be identical with A. sagittalis as the latter occurs in Sweden and Newfoundland. Some of the ventral valves are very low, but specimens of a similar char- acter occur in the limestones of Sweden and Newfoundland. Formation and locality. — Middle Cambrian: (lln) About 3,000 feet (914.4 m.) above the Lower Cambrian and 1,400 feet (426.7 m.) below the Upper Cambrian, in the upper part of the limestone forming la of the Marjum limestone [Walcott, 1908f, p. 179], in the long cliff southeast of Marjum Pass [Walcott, 1908f, Pis. XIII and XV], House Range, Millard County, Utah. A somewhat similar shell that also strongly suggests Acrotreta sagittalis occurs in the Middle Cambrian limestones near Antelope Springs, in the House Range, Millard County, Utah. As the material is not very good or abundant, nothing more will be done at present toward identifying it. Acrotreta sagittalis magna (Matthew). Plate LXVI, figures 4, 4a-f . Linnarssonia belli magna Matthew, 1897, Trans. Roy. Soc. Canada for 1897, 2d ser., vol. 3, sec. 4, No. 7, pp. 169-170, PL I, figs. la-b. (Described and discussed as a new variety. The specimens represented by figs, la and lb are redrawn in this monograph, PI. LXVI, figs. 4b and 4-4a, respectively.) Acrotreta sagittalis magna (Matthew), Walcott, 1902, Proc. U. S. Nat. Mus., vol. 25, pp. 595-596. (Discussed as below.) In addition to the material collected by Matthew, I have a number of specimens collected by me at the typical locality at Hastings Cove. A comparison with a series of specimens of Acrotreta sagittalis (Salter) from St. Davids, Wales, and of A. sagittalis transversa (Hartt) shows at once that the form Matthew named is very closely related to both. The length and size of the median ridge, and the position of the central scars of the dorsal valve, and the size and position of the cardinal scars of the ventral valve are the internal characters that Matthew depends upon to distinguish the variety magna. AU of the charactei's are fully covered by the variations in the same characters in A. sagittalis and its variety transversa. The nearly circular form of the variety magna is about the onlj'' character that can be considered of value, and that is very closely approached by some specimens of A. sagittalis (PI. LXXI, figs. 3b, 3e, 3h). It is not probable that the New BrunsAvick shell is a variety of Acrotreta belti (Davidson) (PL LXXVII). In order to have all the data possible for the student I have illustrated Matthew's types, which he kindly sent me for the purpose, also specimens I found in the lime- stone at the base of the beds carrying Paradoxides at Hanford Brook. Formation and locality. — Middle Cambrian: (2s) « Limestones in 'upper part of Paradoxides zone, Hastings Cove [Matthew, lS98b, p. 3S], on Kennebecasis Bay, 0.5 mile {0.8 km.) northeast of Torryburn, on the Intercolonial Rail- way, northeast of St. John; (2i) sandstones of Division lb3 of Matthew's [1895a, p. 108] Protolenus zone, Hanford Brook; and (21) limestones at base of Paradoxides zone, Hanford Brook; all in St. John County, New Brunswick, Canada. o 2s is the type locality, though the specimens in the United States National Museum collections to which that number is assigned were collected later than the type specimens. ACROTRETIDiE. 707 ACROTRETA SAGITTALIS TACONICA (Walcott) . Plate LXXI, figures 1, la-o. Linnarssonia taconica Walcott, 1887, Am. Joiir. Sci., 3d ser., vol. 34, pp. 189-190, PL I, figs. 18, 18a-d. (Described and discussed as a new species. The specimens represented by figs. 18a-c are redrawn in this monograph, PI. LXXI, figs, lo, Ic, and Ih, respectively.) Linnarssonia taconica Walcott, Oehlert, 1S89, Annuaire geologique universel for 1888, tome 5, p. 1138. (Described in French in a review of the preceding reference.) Linnarssonia sagiitalis taconica Walcott, 1889, Am. Jour. Sci., 3d ser., vol. 38, p. 36. (Stratigraphic position mentioned.) Linnarssonia sagittalis taconica Walcott, 1891, Tenth Ann. Rept. U. S. Geol. Survey, pp. 610-611, PI. LXVIII, figs. 1, la-d. (This description and the figures are copied from Walcott, 1887, p. 189, PL I, figs. 18, 18a-d.) Acrotreta sagittalis taconica Walcott, 1902, Proc. U. S. Nat. Mus., vol. 25, pp. 596-597. (Characterized and discussed as below.) This variety is characterized by the uniformly shorter median ridge of the dorsal valve. The ventral valve appears to be identical \\dtli those of Acrotreta sagittalis (Salter) from Andra- rum, which are embedded in the same character of matrix as the variety taconica. This is the second representative of the genus found in association with the Olenellus fauna. Acrotreta prim8e,va Walcott occurs in the upper zone of the OleneUus fauna in Nevada, and this is in the upper portion of the same fauna in the Appalachian region. Its association with Microdiscus connexus, a representative of Microdiscus punctatus of the Paradoxides zone of New Brunswick, also serves to connect it %vith Acrotreta sagittalis. It appears to be one of the few forms that connect the Atlantic Province Cambrian fauna mth that of the Appalachian Province. It has been found m abundance in the Lower Cambrian of the Canadian Rocky Mountains, thus extending its range to the CordiUeran Province. Formation and locality. — Lower Cambrian: (36b) Limestone near schoolhouse No. 12, near Greenwich; (338g) limestone in the town of Greenwich; (33 and 338c) limestone at and near Rock Hill schoolhouse, near North Green- wich; (338e) limestone a little west of North Greenwich; (338f) limestone near Argyle, 8 miles (12.8 km.) north of Greenwich; (36 and 338d) limestone 1 mile (l.(i km.) south of Shushan; (338x) limestone 0.5 mile (0.8 km.) south of Coila, just east of Cambridge; (43a) limestone 1 mile (1.6 km.) east-northeast of Salem; (45a) limestone at McNaughton Comer, 1 mUe (1.6 km.) east of Salem; and (37b) limestone 0.25 mOe (0.4 km.) east of Salem; all in the Cambridge quadrangle (U. S. Geol. Sm'vey), Washington County, New York. (35) Limestones 1.5 mUes (2.4 km.) north of Bald Mountaiii, 3.5 miles (5.6 km.) north-northwest of Greenwich; and (338h) limestone on the summit of Bald Mountain, about 2 miles (3.2 km.) northwest of Greenwich; both in the SchuylervUle quadrangle (U. S. Geol. Smn^ey), Washington County, New York. (34) Limestone on roadside a little west of the bridge over Poultney River at Low Hampton, about 5 miles (8 km.) east-northeast of \Miitehall; (39) limestone south of the Delaware and Hudson Railroad track on the road running south-southwest from Low Hampton, about 5 miles (8 km.) east-northeast of "WTiitehall; (45b) limestone near the roadside about 1,200 feet (366 m.) east of Bristol's house, near Low Hampton, about 5 miles (8 km.) east- northeast of ■\\Tiitehall ; and (338a) limestone in the northeast section of Whitehall township; all in the Whitehall quadrangle (U. S. Geol. Sm-vey), Washington County, New York. (20a) Gray litnestone, interbedded with shaly slates, in a lane west of Lafayette Stevens's house, about 100 yards (91.4 m.) from the main road, in the southern part of 'WTiitehall township; (22) limestone 1.5 miles (2.4 km.) north of North Granville; and (38a) limestone 2 miles (3.2 km.) south of North Granville, on the road which turns south from the road running between that village and Truthville, 4 miles {6.4 km.) west-northwest of Granville; all in the Fort Ann quadrangle (U. S. Geol. Surs'ey), Washington County, New York. (22a) Limestone in Penrhyn quarries. Middle Granville, Mettawee quadrangle (U. S. Geol. Sm-vey), Washington County, New York. (338b) Limestone on Kinderhook Creek near Stockport Paper Mill; (29) limestone just above the bridge at the Stockport Paper Mill, on Kinderhook Creek; (44b) limestone near North Chatham; and (32a) limestone 0.75 mile (1.2 km.) west of Riders Mills on the Harlem Extension Railroad, about 9 miles (14.4 km.) north-northeast of Chatham; all in the Kmderhook quadrangle (U. S. Geol. Sm-vey), Columbia County, New York. (44a) Limestone on Valatie Kill, near the line between Nassau and Schodack townships, near the line between the Ti-oy and Kinderhook quadrangles (U. S. Geol. Survey); (338y) limestone north of Eagle Mills; (338) limestone at Schodack, northeast comer of the Coxsackie quadrangle (U. S. Geol. Sm-vey); and (29a) limestone 1 mile (1.6 km.) below the New York Central Railroad depot at Schodack; all in Rensselaer County, New York. 708 CAMBRIAN BRACHIOPODA. (58k) Just below the Middle Cambrian in limestones forming 1 of the Mount Whyte formation [Walcott, 1908c, p. 240 (.9)]; (57m) about 50 feet (15 m.) below the Middle Cambrian in a siliceous shale correlated with lb of the Mount ^^lyte formation on Mount Bosworth [Walcott, 1908f, p. 213]: (57e) about 115 feet (35 m.) below the Middle Cambrian, in limestone correlated with the top of Ic of the Mount TOiyte formation on Mount Bosworth [Walcott, 19081, p. 213]; (57r and 58s) about 150 feet (46 m.) below the Middle Cambrian, near the base of the limestones forming 3 of the Mount ^^■hyte formation [Walcott, 1908c, p. 241 (10)]; and (35f) about 300 feet (91 m.) below the Middle Cambrian, in the limestone forming 6 of the Mount WTiyte formation [Walcott, 1908c, p. 242 (11)]; all on Mount Stephen, just above the tunnel on the north shoulder, 3 miles (4.8 km.) east of Field, British Columbia. (57s) About 160 feet (49 m.) below the Middle Cambrian, near the base of the gray oolitic limestone forming lb of the Mount \ATiyte formation [Walcott, 19081, p. 212], on Mount Bosworth, north of the Canadian Pacific Railway between Hector and Stephen, on the Continental Divide between British Columbia and Alberta, Canada. ACROTRETA SAGITTALIS TRANSVERSA (Hartt). Plate LXXII, figures 1, la-k. Obolella transversa Hartt, 1868, Acadian Geology, by Dawson, 2d ed., p. 644. (Characterized.) Obolella transversa Hartt, 1878, idem, 3d ed., p. 644. (Copy of preceding reference.) Obolella transversa Hartt, Walcott, 1884, Bull. U. S. Geol. Survey No. 10, p. 16, PL I, figs. 5 and 5a. (Original descrip- tion copied and species discussed. The specimens represented by figs. 5 and 5a are not redrawn in this mono- graph, but better figures of them are given by Walcott, 1891a, PL LXVIII, figs. 2a and 2c, respectively.) Linnarssonia transversa (Hartt), Walcott, 1885, Am. Jour. Sci., 3d ser., vol. 29, p. 115, figs. 3, 4, 6, and 7, p. 116. (Dis- cussed as the type of the new genus Linnarssonia. Figs. 3 and 7 are drawn from the specimens figured by Wal- cott, 1884a, PL I, figs. 5 and 5a, respectively.) Linnarssonia transversa (Hartt), Matthew, 1886, Trans. Roy. See. Canada for 1885, 1st ser., vol. 3, sec. 4, No. 4, p. 35, PL V, figs. 11, lla-e. (Discussed. Casts of the two specimens represented by figs. 11, lla-e are figured by Walcott, 1891a, PL LXVIII, figs. 2d and 2a.) Obohlla transversa Haett, 1891, Acadian Geology, by Dawson, 4th ed., p. 644. (Copy of Hartt, 1868, p. 644.) Linnarssonia sagittalis transversa (Hartt), Walcott, 1891, Tenth Ann. Rept. U. S. Geol. Survey, Description of PI. LXVIII, figs. 2a, 2c, and 2d. (No text reference. Figs. 2a and 2c are drawn from the specimens figured by Walcott, 1884a, PL I, figs. 5 and 5a, respectively. Fig. 2d is drawn from the specimen figured by Walcott, 1885a, fig. 6, p. 116. Figs. 2d and 2a are drawn from casts of the two specimens figured by Matthew, 1886, PI. V, figs. 11, lla-e.) Linnarssonia transversa (Hartt), Hall and Claeke, 1892, Eleventh Ann. Rept. State Geologist New York for 1891, PL III, figs. 22 and 23. (Fig. 22 is drawn from the specimen figured by Matthew, 1886, PL V, fig. 11.) Linnarssonia transversa (Hartt), Hall and Claeke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, p. 108, PL III, figs. 38-42. (Mentioned in the text. Figs. 38-39 and 40^2 are drawn from the specimens figured by Matthew, 1886, PL V, figs, lie and 11, respectively. Figs. 42 and 39 are copied from figs. 22 and 23, respectively, of the preceding reference.) Linnarssonia transversa (Hartt), Matthew, 1895, Trans. New York Acad. Sci. for 1894-95, vol. 14, p. 125, PL V, figs. la-c and 2a-c. (Locality mentioned. The figures are copied from Matthew, 1886, PL V, figs. 11, lla-e.) Linnarssonia sagittalis transversa (Hartt), Frbch, 1897, Additional plates inserted in 1897 in Lethaea geognostica, pt. 1, Lethffia pateozoica. Atlas, 1876, PL lA, fig. 3b. (No text reference. Fig. 3b is copied from Walcott, 1891a, PI. LXVIII, fig. 2d.) This is the representative of Acrotreta sagittalis (Salter) in the Paradoxides zone of New Brunswick. Many shells are more transverse in outline than the average of At sagittalis, but examples of the latter (PL LXXI, figs. 3, 3a, 3g, 3j) are nearly as much so and the interior casts show a striking similarity in the Welsh and Acadian forms. The range of variation in each form is nearly as great as the variation between the two. In view of this, I think it is best to characterize transversa as a variety of A. sagittalis. The shells from the "Protolenus beds" of Hanford Brook also vary in form from the nearly circular variety magna to the transverse forms included under transversa. Formation and locality.— Upper Cambrian: (3) Shales 300 feet (91.4 m.) above the Paradoxides zone, Manuels Brook, Conception Bay, Newfoundland. Middle Cambrian: (2f and 2g) Sandstones of Division Ibl : (2h) overlying 2g in the sandstones of Division lb2; (2) sandstones of Division lb2; (2i) sandstones of Division lb3; (2k) overlying 2i in the sandstones of Division lb3; and (301b) sandstones of Division lb5 and higher; all in Matthew's [1895a, p. 108] Protolenus zone, Hanford Brook, St. John County, New Brunswick. (301c) Sandstones of the St. John formation, at Coldbrook; and (301k) St. John formation, in the city of St. John; both in St. John County, New Brunswick. ACROTEETID^. 709 ACROTRETA SCHMALENSEEI Walcott. Plate LXX, figures 1, la-s. Not Acrotreta sodalis von Seebach, 1S65, Zeitschr. Deutsch. geol. Gesell. for 1865, Bd. 17, p. 341, PI. Villa, figs. 1^. (This species is referred in this monograph to Acrotreta sodalis.) Acrotreta sodalis Linnarsson [not von Seebach], 1876, Bihang till K. svensk. Vet.-Akad. Handl., Bd. 3, No. 12, pp. 16-lS, PI. Ill, figs. 32-35. (Described and discussed in English.) fAcrotreta sodalis Linnarsson, 1877, Geol. Foren. i Stockholm Forhandl., No. 40, Bd. 3, No. 12, p. 374. (Not figured, and may belong with either Acrotreta schmalenseei or A. sodalis.) Acrotreta sodalis Linnarsson, Wallerius, 1895, Lndersokningar ofver Zonen med Agnostus Ixvigatus i Vestergotland, p. 66. (Discussed in Swedish.) Acrotreta schmalensei^ta.coTr, 1902, Proc. U. S. Nat. Mus., vol. 25, pp. 597-598. (Described as below as a new species.) As in the case of many other species of this genus, the student is referred to tlie series of figures illustrating it for information as to the external outline, form, and convexity of the two valves and the range of known variation. The collections of the United States National Museum contain a large series of specimens from which the shells illustrated were selected. The broad false area has a shallow, faint median groove on some specimens, and on others no traces of it have been seen. The pedicle aperture, which is exceedingly minute, is situated at the extreme apex of the ventral valve; the cast of the base of the pedicle tube is clearly shown in interior casts of the v?Jve (PI. LXX, figs. If and Ih). One of the distinguishing characters is the cast of the large mam vascular sinuses on each side of the visceral area, a feature which varies (PI. LXX, figs, le, li, and Is). The casts of the interior of the dorsal valve (figs. Ij-lp) are interesting and instructive in showing the considerable variation in the size and length of the median ridge, and the size of the cardinal and central scars. The shell is small and built up of a thin outer layer and several inner layers or lamellse more or less oblique to the outer layer. The outer surface is marked by fine concentric strise and lines of growth, and the inner surfaces of the lamellae by concentric striae and fine radiating strise. The average length of the opening of the valves is 1.5 to 2 mm., and the width is usually a little more. Observations. — All of the specimens illustrated are from the Paradoxides fordihammeri zone. They appear to be identical with the figures of Acrotreta sodalis given by Linnarsson [1876, PL III, figs. 32-35], but are not like those given by von Seebach [1865, PI. Villa, figs. 1-4]. Those of the latter represent a shell with strong concentric striae and median groove on the false area, characters that Linnarsson states that he did not find on his specimens. Among the collections made for me by Mr. G. Schmalensee, a collector in the Geological Sur- vey of Sweden, I find a larger Acrotreta than the one described by Linnarsson [1876, p. 16], which agrees with the description of A. sodalis given by von Seebach [1865, p. 341] and with his figures. Linnarsson writes that he thinks that von Seebach had representatives of several species before him when he wrote his notes on A. sodalis. With this I fully agree, but with the collections now before me from Bornholm and Oeland, I think the specific name A. sodalis should be given to the larger shell, illustrated by von Seebach [1865, PI. Villa, figs. 1-4], and a new name given to the smaller and very distinct shell illustrated by Linnarsson [1876, PI. Ill, figs. 32-35]. In recognition of the faithful and intelligent work of Mr. G. Schmalensee, I take pleasure in naming the species in his honor. Acrotreta schmalenseei is of the type of A. subconica Kutorga, but is much less elevated. It may be compared with A. microscopica (Shumard) and A. gemma Billings among American species. Formation and locality. — Middle Cambrian: (323b) Limestone of the Paradoxides celandicus zone, at Wind- juelandet, Ringsaker, Pro^dnce of Hedemerken, Norway. (320n) Limestones of the Paradoxides forchhammeri zone at Lovened, Djupadal, 19 miles (30.6 km.) south-southeast of Skara; (320e) limestone at Munkesten, north of Hunneberg; (321q) limestones of the Paradoxides forchhammeri zone at Munkesten, north of Hunneberg; and (320m [Linnarsson, 1876, p. 18]) limestone of the Paradoxides forchhammeri zone at Kinnekulle, northeast of Lidkoping; all in the Pro^ance of Skaraborg, Sweden. (8w) Liviestones of the Paradoxides forchhammeri zone at Andrarum; and (330c [Wallerius, 1895, p. 66]) Andrarum limestone, at Andrarum; both 20 miles (32 km.) northwest of Simrishamn, Province of Christianstad, Sweden. 710 CAMBRIAN BRACHIOPODA. (320d) Exsulans limestone in the lower part of the Paradoxides tessini zone, at Fogelsang, 5 miles (8 km.) east of Lund, Pro^^nce of Malmohus, Sweden. (310c [Wallerius, 1895, p. 66]) Limestone of the Paradoxides celandicus zone, on Oeland Island; (SlOp [Linnarsson, 1876, p. 18]') limestone of the Paradoxides celandicus zone at Borgholm; and (310b) dark-brown limestone at Borgholm, on Oeland Island; all in Sweden. (16j) Limestone of the Paradoxides forchhammeri zone at Laesaa; (16h) limestone of the same zone at Borregaard; and (334 [\\'alleriiis, 1S95, p. 60]) limestone of the Paradoxides forchhammeri zone; all on Bornholm Island, Denmark. ACROTEETA SEEBACHI Walcott. Plate LXXVII, figures 3, 3a. Acrolreta secbachi 'Walcott, 1902, Proc. IT. S. Nat. Mus., vol. 25, pp. 598-599. (Described and discussed as below . as a new species.) Acrotreia seebachi 'Walcott, Moberg and Segbrberg, 1906, Medd. fr&n Limds Geol. Faltklubb, Ser. B, No. 2 (Aftryck ur K. Fysiografiska Sallskapets Handl., N. F., Bd. 17), pp. 66-67. (Characterized and discussed in Swedish.) Among the fragments of trilobites in the Ceratopyge limestone collected by Schmalensee there are a few specimens of a species of Acrotreta distinct from A. schmalenseei Walcott and A. socialis von Seebach. The ventral valve is relatively low, with the false area nearly vertical. A cast of this valve shows the cardinal scars on each side high up toward the apex; small main vascular sinuses and apical callosity. False area rather large and marked by a slight indica- tion of a median depression that is recognized by a slight undulation in the transverse striae. Surface marked by fine threadlike concentric striae and lines of growth. A broken dorsal valve has a broad median sulcus and a small distinct beak at the posterior margin. The valves are slightly transverse. A large ventral valve measures 3 mm. in width by 2.5 mm. in length. The surface stria and the cardinal scars serve to distinguish this species from others known to me. Acroihelef ceratopygarum (Brogger) is from the Ceratopyge shales, but it has a low ventral valve with the false area sloping forward. After deciding that a new species was represented in the material received from Schmalen- see, I studied a fine series of specimens that Dr. W. C. Brogger kindly sent me. In material collected by Schmalensee from the Ceratopyge shale at Borgholm, Oeland Island, Sweden, some imperfect specimens suggest Acrotreta seebachi; they might equally well be referred to A. carinata Moberg and Segerberg, or A. circularis Moberg and Segerberg. The specific name was given in honor of Dr. K. von Seebach. Formation and locality." — Passage beds between the Upper Cambrian and the Ordovician: (8x) Ceratopyge, • limestone at Slemmestad, about S miles (4.8 km.) southiuest of Christiania; (323d) Ceratopyge limestone (Etage Say- of Brogger) at Christiania; (323f) lower part of the Ceratopyge limestone [Brogger, 1882, pp. 16 and 17] at 'Vestfossen, 10 miles (16.1 km.) west-southwest of Christiania; (323h) blue Ceratopyge limestone [Brogger, 1882, p. 17] at "Vestfossen, 10 miles (16.1km.) west-southwest of Christiania; and (323e) Ceratopyge limestone at Engervik, near Christiania; all in Norway. TTpper Cambrian: (310d) C'cmtop2/9« slate at Borgholm, Oeland Island, Sweden. Specimens somewhat doubtfully referred to this species occur at the following locality: Passage beds between the Upper Cambrian and the Ordovician: (323g) Ceratopyge limestone (Etage 3a}- of Brogger), at Vaekkero, in the Christiania region, Norway. Acrotreta shantxjngensis Walcott. Plate LXIX, figures 5, 5a-e. Acrotreta shantungends Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 301-302. (Described and discussed as below as a new species.) Shell small. Ventral valve a low cone with the apex a little forward of the posterior margin, which is slightly flattened; apex minute, directed backward and projecting slightly over the faintly defined false area. The cast of the interior shows that the apical callosity was rather large and that the main vascular sinuses were well defined on each side of it ; the cardinal scars are small and not prominent. o Localities 8x and 310d are represented in the collections of the United States National Museum; the others are in the collection of the University of Christiania. ACROTRETID^. 711 Dorsal valve slightly convex; apex marginal; surface marked by a rather broad, shallow median depression that begins on the umbo and gradually widens toward the front margin. The interior of the dorsal valve has a strong median ridge extending from the posterior margin two-thirds the distance toward the front. A small, elevated cardinal scar occurs on each side of the median ridge a little in advance of the posterior margin. Main vascular sinuses rather strong; they start beneath the apex and extend forward a short distance from the outer lateral margin of the shell. Surface marked by fine concentric strije and lines of growth. Oiservations. — This shell m size and general form is closely related to Acrotreta microscopica (Shumard) (PI. LXVII) of the Middle Cambrian fauna of the United States. The specific name is derived from Shantung, China. Formation and locality. — Middle Cambrian: (C37) Upper part of the Kichou limestone" in dense black lime- stone nodules in green-gray shales 10 feet (3 m.) below the base of the chff limestone, 8 miles (12.8 km.) south of Ting- hianghien; and (C71) massive cliff-making limestone in the central portion of the Kichou formation [Willis and Blackwelder, 1907, pp. 139 and 145 (2d list of fossils)], 4 miles (6.4 km.) southwest of Tungyu, Shansi, China. (CI) Lower shale member of the Kiulung gi-oup [Blackwelder, 1907a, pp. 37 and 40 (part of the 3d list of fossils), and fig. 10 (bed 4), p. 38], 2 miles (3.2 km.) south of Yenchuang; and (C62) earthy layer in the middle limestone member of the Kiulung group [Blackwelder, 1907a, pp. 37 and 40 (last list of fossils), and fig. 10 {base of bed 7), p. 38], 2.5 miles (4 km.) south of Yenchuang, on the north-northeast spur of Hulushan; both in the Sintai district, Shantung, China. A shell apparently identical with Acrotreta shantungensis was collected at the following locality: Middle Cambrian: (C32) A fine-grained, bluish-black limestone bowlder believed to have come from the lower part of the Kisinling limestone [Blackwelder, 1907b, p. 272], collected in river drift 1 mile (1.6 km.) south of Chon- pinghien, on Nankiang River, southern Shensi, China. Acrotreta signalis Walcott. Plate LXIX, figure 4. Acrotreta signalis Walcott, 1902, Proc. U. S. Nat. Mus., vol. 25, p. 599. (Described and discussed as below as a new species.) Ventral valve transverse, broadly ovate; height about one-third the length; apex directed backward on a line with the posterior margin, which is transverse and slightly undulated at the center by the median furrow of the false area ; apex with a minute apical foramen which is directed backward. Surface marked by fijie concentric strinj and lines of growth that at the median furrow of the false area curve toward the posterior margin. Shell small, 1.5 mm. long by about 1.75 mm. in width. Shell buUt up of several very thin layers or lamellae. Observations. — In all of the extensive collections made from the Cambrian sandstones of the upper Mississippi Valley, only two ventral valves of any species of Acrotreta have been found, as far as Ivnown to me. These occur in association with Lingulella (Lingulepis) acuminata (Conrad) and the shells have the color and appearance of those of that species, shiny light gray to white, the original coloring matter having been leached out. Only the exterior of the ventral valve is known. This compared with A. microscopica (Shumard) (PL LXVII) shows a less elevated ventral valve and a less distinct false area. It also has a marked median groove on the false area. It recalls A. idaJioensis Walcott, but diflFers in being more depressed and in having a stronger groove on a narrower false area. Formation and locality. — Middle Cambrian: (328e') "St. Croix sandstone" at St. Croix Falls, Polk County, Wisconsin. Acrotreta socialis von Seebach. Plate LXXIII, figures 3, 3a-c, 4, 4a-e. Acrotreta socialis von Seebach [not Linnarsson], 1865, Zeitschr. Deutsch. geol. Gesell. for 1865, Bd. 17, p. 341, PL Villa, figs. 1-4. (Described and discussed in German, as a new species. Figs. 1-4 are reproduced in this mono- graph, PL LXXIII, figs. 3, 3a-c, respectively.) " The fossils from this locality are not listed, but the presence of Cambrian strata at the locality is mentioned by Willis and Blackwelder [1907, p. 1461. 712 CAMBRIAN BRACHIOPODA. Not Arrotreta snciaUs Linnarsson, 1876, Bihang till K. svensk. Vet.-Akad. 5andl., Bd. 3, No. 12, pp. 16-18, PI. Ill, tigs. 32-35. (Described and discussed in English. This species is referred in this monograph to Acrolreia schmalcnscei.) fAcTotreta sodalis Linnarsson, 1877, Geol. Foren. i Stockholm Forhandl., No. 40, Bd. 3, No. 12, p. 374. (Not figtired, and may belong with either Acrotreta sodalis or Acrotreta schmalenseei.) Acrotreta socialis von Seebach, Walcott, 1902, Proc. U. S. Nat. Mus., vol. 25, pp. 599-600. (Described and discussed essentially as below.) Not Acrotreta cf. sodalis Matthew, 1902, Bull. Nat. Hist. Soc. New Brunswick, vol. 4, pt. 5, No. 20, pp. 392-894, PL XV, figs. 5a-k. (Described and discussed. This species is referred in this monograph to Acrotreta sp. undt.) Not Acrotreta cf. socialis Matthew, 1903, Geol. Survey Canada, Kept. Cambrian Rocks Cape Breton, pp. 183-185, PL III, figs. 5a-k. (Copy of preceding reference. This species is referred in this monograph to Acrotreta sp. undt.) The species described and illustrated by von Seebach [1865, p. 341, PI. Villa, figs. 1-4] as Acrotreta socialis is characterized by a well-marked, concentrically striated surface and a strong median groove in the false area. In the collections made for me by Mr. Schmalensee at Borg- holm, Oeland Island, I find associated with Paradoxides celandicus an Acrotreta that has these characters. All the specimens from the Paradoxides for chhammeri zone in the large collection before me, with the exception of one ventral valve, belong to a distinct species which I have named A. scJimalenseei. Von Seebach evidently had specimens of the latter species, also of a species of Acrotreta from the Ceratopyge limestone, as he mentions the occurrence of A. socialis at both horizons. The external form, as far as known to me, is shown by the figures. There is some variation in the height of the ventral valve and in the outline of the margins of the valves. The false area is clearly defined and marked by a strong, rather broad median groove. The pedicle aperture is at the apex of the ventral valve and quite readily seen in several specimens, a char- acter in strong contrast with the minute aperture at the apex of A. scJimalenseei Walcott. Shell formed of several thin layers or lamellae that show very plainly where the thin outer layer is exfoliated. Surface marked by striae and lines of growth that are very distinct on some shells and less so on others; the concentric striae occur on all the lamellae of the shell and on the inner surface; fine radiating striae are to be found on the inner surface. The cast of the interior of the ventral valve shows the presence of a large apical callosity and unusually large pedicle tube and main vascular sinuses on each side of the visceral cavity. The cardinal scars are well defiiied in both the ventral and dorsal valves. Casts of the interior of the dorsal valve show a strong median ridge, central scars, and fairly well-defined main vascular sinuses. Von Seebach [1865, p. 341] describes the surface as having minute warts on it. I find numerous fragments of the shell of Acrothele {Redlichella) granulata (Linnarsson) associated with Acrotreta socialis, and it may be that von Seebach mistook the surface of this shell for that of the species he was describing. No known species of Acrotreta has such a surface. A large ventral valve has a diameter of 5 mm. and a height of 2.5 mm. The average size is about 3 mm. in diameter. A single ventral valve found by Schmalensee at Andrarum appears to belong to this species. It is a cast of the interior of the shell, and shows concentric ridges or undulations of growth, well-defined cardinal scars, large apical callosity, and short but strong main vascular sinuses (PI. LXXIII, fig. 4b). This species belongs to the A. subconica Kutorga group of species with a broad false area and well-defined median groove. Its surface is more strongly marked by concentric striae than any other species of the genus, and the shell is also thicker. Gronwall [1902, p. 39] and Linnarsson [1877, p. 374] refer specimens to Acrotreta socialis, but do not accompany the references by descriptions or figures, and I therefore can not decide whether to include the forms with Acrotreta socialis or Acrotreta scJimalenseei. Matthew [1902b, p. 392] has compared some imperfect specimens of a species of Acrotreta from McNeil Brook, Cape Breton, with Acrotreta socialis von Seebach. The shells, as far as can be determined, do not belong to this species. They are about the same size, but the ventral valve is depressed and more like that of Acrotreta sagittalis magna (Matthew) . I can not identify ACROTRETID^. 713 the species with the material available for study, and I have entered it in this monograph as Acrotreta sp. undt. (see p. 715). Formation and locality. — Middle Cambrian: (8z) Limestones of Paradoxides celandicus zone, Borgholm, Oeland Island; (320n) limestones of the Paradoxides forchhammeri zone at Lovened, Djupadal, 19 miles (30.6 km.) south-south- east of Skara, Province of Skaraborg; and (8w) limestones of Paradoxides forchhavimeri zone at Andrarum, 20 miles (32.2 km.) northwest of Simrishamn, Province nf Christianstad ; all in Sweden. (334g [Seehach, 1S65, pp. 340 and 341\) Limestones on Bornholm Island, Denmark. ACROTKETA SPINOSA Walcott. Plate LXXIX, figures 4, 4a-g. Acrotreta spinosa Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 302. (Characterized as below, as a new species.) The general form of this shell is much like that of Acrotreta idahoensis Walcott (PL LXVIII, figs. 2, 2a-g). It differs in having a straighter posterior margin. The distinguishing character of the species is the spinose outer surface. The surface is marked by fine concentric hnes of growth at irregular intervals, with numerous, very fine, threadUke striae between. On some shells occur radiating, more or less irregular, fine, rounded ridges that are formed by the elevated elongate spine bases. When these elongate bases are irregularly arranged the radiat- ing ridges are not present. Owing to their minute size, the spinules are rarely seen. Formation and locality. — Tipper Cambrian: (65) Limestone on east side of Sierra Canyon, opposite Pinnacle Peak; (62a) limestone on east side of Sierra Canyon, opposite the Jackson mine; (62) limestone in the Dunderberg shale [Walcott, 1908f, p. 184], in canyon immediately north of Adams Hill; and (61) limestone in the Dunderberg shale [Walcott, 1908/, p. 184], a little south of the Hamburg mine; all in the Eureka district [Hague, 1892, Atlas], Eureka Coimty, Nevada. Acrotreta subconica Kutorga. Plate LXXIII, figures 2, 2a-i. Acrotreta subconica Kutorga [not Meek], 1848, Verhandl. Russ.-kais. min. Gesell. St. Petersburg for 1847, No. 12, p. 275, PI. VII, figs. 7a-c. (Described in German as a new species; see below for translation. Figs. 7a, 7b, 7c, 7b', and 7c' are reproduced in this monograph, PL LXXIII, figs. 2, 2a-d, respectively. The specimens repre- sented by figs. 7a, 7b', and 7c' are redrawn in this monograph, PI. LXXIII, figs. 2e, 2h, and 2i, respectively. Figs. 2f and 2g on PI. LXXIII of this monograph represent one of Kutorga's type specimens, but he figured only the dorsal valve, 1848, PI. VII, fig. 7c'.) Acrotreta Morris, 1849, Annals and Mag. Nat. Hist., 2d ser., vol. 4, PI. VII, figs. 4a-b. (No text reference. Figs. 4a and 4b are copied from Kutorga's figures, 1848, PI. VII, figs. 7b' and 7c', respectively, of Aa-otreta subconica.) Acrotreta subconica Kutorga, Davidson, 1853, British Fossil Brachiopoda, vol. 1, Introduction, No. 3, PI. IX, figs. 271-275. (No text reference. Figs. 271-275 are copied from Kutorga, 1848, PI. VII, figs. 7c, 7a, 7b, 7b', and 7c', respectively.) Acrotreta subconica Kutorga, von Seebach, 1865, Zeitschr. Deutsch. geol. Gesell. for 1865, Bd. 17, p. 341. (Men- tioned in discussion of A. socialis.) Not Acrotreta subconica Meek, 1873, Sixth Ann. Rept. U. S. Geol. Survey Territories for 1872, p. 463. (This species is referred in this monograph to Acrotreta idahoensis.) Acrotreta subconica Kutorga, Quenstedt, 1885, Handbuch der Petrefactenkunde, Aufl. 3, p. 755, PL LVIII, fig. 51. (Mentioned. Fig. 51 is roughly copied from Kutorga, 1848, PI. VII, fig. 7b.) Acrotreta subconica Kutorga, Walcott, 1902, Proc. U. S. Nat. Mus., vol. 25, pp. 600-601. (Original description translated and type specimens discussed as below.) The original description by Kutorga follows: Strongly conical; the deltidium-like furrow narrow and plainly impressed. Innumerable growth wrinkles run on the whole surface of the shell horizontally, and make deflections only in the fmrow, the convexity of which is turned toward the base of the cone. Height of the cone, 0.014 ; length of the base of the ventral valve, 0.012 ; breadth of the same, 0.015 . Four specimens, of which one is complete and three are without ventral valve. From the collection of Herr von Volborth. On one specimen with the apex broken off I investigated the surface of the fracture under the microscope, with a magnification of forty-five times, and found on it two cruriform, shallow impressions similar to those on the casts of the Siphonotretes. Their surface was polished and with impressions of growth folds, and between the extremities of the crura, in the neighborhood of the area-like hinge surface, a columniform fragment of the mold of the siphon. From this it follows that the broken-off tip, just as the beak of the Siphonotretes, was solid and contained a cylin- drical siphon. 714 CAMBRIAN BRACHIOPODA. Ohservations. — Through the courtesy and permission of Dr. Fr. Schmidt, Dr. Fr. von Huene kindl_y sent me the types of tliis species, which he had been studying. One of tliem preserves the outer shell at the apex. It shows a minute foraminal aperture on the back side of the apex and a strong median groove on the false area. The outhnes of the pedicle valve vary from the somewhat diagrammatic drawings of Kutorga [1848, PI. VII, figs. 7a-c], and there is some variation among the five specimens representing the types. The characters of the shell are shown by the figures on Plate LXXIII. Formation AND locality. — Ordovician: (336) Echinosphserites limestone, horizon Cla [Fr. Schmidt, personal communication, 1906], Popowka, near St. Petersburg, Russia. ACROTKETA UI.RICHI Walcott. Plate LXXVIII, figure 3. Acrotreta ulrichi Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, pp. 96-97, PI. IX, fig. 3. (Described and discussed as below as a new species. Fig. 3 is copied in this monograph, PI. LXXVIII, fig. 3.) This species is founded on a single specimen of a finely preserved ventral valve. The outHne of the aperture is nearly circular, except for a short transverse portion beneath the false area; surface moderately convex, with the apex curving and ending beyond the posterior margin so that the minute foraminal aperture opens backward; a small false area is indicated by a shght incurving at the cardinal angles; the area is without traces of a median furrow. Surface of shell marked by very fine, concentric strise and hues of growth. Length and width of aperture 2 mm. ; convexity of ventral valve 1 mm. Ohservations. — This species is claaracterized by its curved umbo and apex, and overhang- ing false area. It most nearly resembles A. curvata Walcott, from which it differs in being less convex, and in the form of its umbo and curved apex. The specific name was given in honor of Mr. E. O. Ulrich. Formation and locality. — Upper Cambrian: (12p) About 225 feet (69 m.) above the igneous rocks, in the limestones of the Reagan sandstone, at the northwestern extremity of the Ai'buckle Mountains, about 4 miles (6.4 km.) east of Homer, Carter County, Oklahoma. Acrotreta uplandica Wiman. Plate LXX, figures 3, 3a-c. Acrotreta uplandica Wiman, 1902, Bull. Geol. Inst. Univ. Upsala, vol. 6, pt. 1, No. 11, p. 54, PI. II, figs. 15-18. (De- scribed in German as a new species. The specimens represented by figs. 15-18 are redrawn in this monograph, PI. LXX, figs. 3, 3a-c, respectively.) Acrotreta uplandensis (Wiman), Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 302. (Characterized as below.) This species recalls at once Acrotreta idahoensis sulcata Walcott. It differs from it in having a broader false area. The surface is marked by fine, threadhke strise that cross the false area and false pedicle groove. Formation and locality. — Middle? Cambrian: (311b) Drift bowlder of gray bituminous sandstone, No. 2 [Wiman, 1902, p. 57], 071 Biludden, about 20 miles {32.2 km.) east of Oefle, Province of Gefleborg; and (Slip) drift bowlder of glauconitic sandstone. No. 1 [Wiman, 1902, p. 57], at Hoganas, parish of Borstil, east of Osthammar, Province of Stockholm; both in Sweden, Acrotreta uplandica limoensis (Wiman). Plate LXX, figures 4, 4a-c. Acrotreta limoensis Wiman, 1902, Bull. Geol. Inst. Univ. Upsala, vol. 6, pt. 1, No. 11, p. 54, PI. II, figs. 19-22. (Char- acterized in German as a new species. The specimens represented by figs. 19-22 are redrawn in this mono- graph, PL LXX, figs. 4, 4a-c, respectively.) Acrotreta uplandica limonensis (Wiman),- Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 303. (Characterized as on p. 715.) ACROTRETID^. 7 15 Wiman states [1902, p. 54] that this form is quite Uke Acrotreta uplandica, but lower, as the height is only one-third of the diameter. It is so close in all other respects that I do not . think that more than a varietal value should be given to the differences mentioned. The specific name is derived from Limon Island, Sweden. Formation and locality.— Middle? Cambrian: (311n) Drift bowlder of bluish calcareous sandstone, No. 6 [Wiman, 1902, p. 57], on Limon Island, about 12 miles (19.3 km.) east-northeast of Gefle, Province of Gefleborg, Sweden, AcKOTRETA sp. imdt. Acrotreta cf. sodalis Matthew [not Linnarsson or von Sbebach], 1902, Bull. Nat. Hist. Soc. New Brunswick, vol. 4, pt 5 No 20, pp. 392-394, PL XV, figs. 5a-k. (Described and discussed.) Acrotreta cf'. sodalis Matthew, 1903, Geol. Survey Canada, Kept. Cambrian Rocks Cape Breton, pp. 183-185, PL III, figs. 5a-k. (Copy of preceding reference.) Matthew describes and illustrates this form and compares it with Acrotreta sodalis von Seebach. A comparison of his specimens with A. sodalis shows the two forms to be distinct. Matthew's specimens are more suggestive of A. sagittalis magna (Matthew) (PI. LXVI, figs. 4, 4a-f) except that the ventral valve is higher. With the original specimens for study it appears best to indicate this form as an unde- termined species. Formation and LOCALITY.-Middle Cambrian: (325a [Matthew, 1903, p. 184]) Shales of Division C2c of Matthew's Bretonian, on the eastern slope of the valley of McNeil Brook, on the road to Trout Brook, Cape Breton, Nova Scotia. Acrotreta sp. undt. Westergard. Acrotreta sp WestekgIrd, 1909, Medd. fran Lunds Geol. Faltklubb, Ser. B, No. 4 (Aftryck ur K. Fysiografiska SiiUskapets HandL, N. F., Bd. 20), pp. 57 and 77, PL II, figs. 25a-b. (Locality mentioned m Swedish.) This species is not described by Westergard, and I have not seen the specimen. It is of mediiim height and appears to be a true Acrotreta. Formation and locality.— Upper Cambrian: (310t) Subzone c of the Dictyograptus slate at Pogelsdng; (310u) subzone c of the Dictyograptus slate at Jerrestad; and (310v) subzone b of the Dictyograptus slate at Tosterup; all Westergard, 1909, pp. 57 and 77] in the Province of Malmohus, Sweden. Genus ACROTHYBA Matthew.^ f&;oo!r, at the top; and dipi, a door.] Acrothyra Matthew, 1901, BuU. Nat. Hist. Soc. New Brunswick, vol. 4, pt._ 4, No. 19, pp. 303-304. (Described and discussed as a new genus.) „, ,,^t ^ Acrothyra Matthew, 1902, Trans. Roy. Soc. Canada for 1902, 2d ser., vol. 8, sec. 4, No. 3, p. 104. (Notes on variation in size etc., of the different species and varieties of Acrothyra.) Acrothyra Matthew, 1903, Geol. Survey Canada, Rept. Cambrian Rocks Cape Breton, pp. 85-86. (Copied from Mat- thew, 1901b, pp. 303-304.) 4CT-o%ra Matthew, 1903, idem, pp. 88-89. (Copied from Matthew, 1901b, p. 304.) Acrothyra Matthew, Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 4, PL XI, and pp. 142 and 146. (Classifica- tion of genus.) Ventral valve elongate conical, with the posterior face more or less flattened to form a false area marked on the median fine by a shaUow groove. Area unknown. The slope of the false area is usuaUy backward so as to throw the apex back of the posterior margin, but in some instances it is directly on a fine with the margin. Pedicle opening minute, shghtly truncating the apex. Dorsal valve strongly convex with the beak marginal. Area unknown. Surface marked by fine, concentric strise and Unes of growth and very fine, irregular, con- centric strise that mosculate so as to give a granulose or pitted surface when seen by a strong lens. The hmer surface of the ventral valve shows fine radiating Imes in some specunens. The shell is built up of several thm layers or lamellae of a calcareocorneous character. The a The svnonvmv for this genus does not give a complete record of the various genera under which the species now included in Acrothyra were formerirST^leso^yZe referenced in which the genus is discussed or described. To complete the record the foUowmg mere generic references are listed: Acrotreta Matthew [1899b, p. 203; 1902b, pp. 390 and 391; 1903, pp. 73 and 95]. 716 CAMBRIAN BRACIIIOPODA. dorsal valve is usually thicker than the ventral valve, and its inner lameUse are arranged more oblique to the outer layer. The cast of the ventral valve indicates a small apical callosity penetrated by a slender pedicle tube. The main vascular sinuses are almost straight from the apex far out toward the anterolateral portion of the valve; in the short valves they diverge quite rapidly, but in the elongated valves the}^ leave but a narrow space for the visceral area. From the anterior margin, of the apical callosity two narrow ridges extend well forward and then curve outward and inward to meet about a central depression or pit that occupies the same relative position as the central depression of the visceral cavit}^ in Oholus and its subgenera. The cardinal scars have not been observed. The interior of the dorsal valve is strongly concave. A slight median ridge is seen in some specimens and in others it is very difficult to determine its presence except in the pos- terior third of the shell, where it is often very strong. On each side of the median ridge there is usually a rather deep groove m which, at about one-tliird the distance from the posterior to the front margins of the valve, the central muscle scars occur; the cardinal scars are clearly defined on each side of the median ridge near the posterior margin. Type. — Acrotreta proavia Matthew. Observations. — This genus is intimately related to Acrotreta and except for the presence in some species of a well-marked visceral area of- a type not known in Acrotreta there would be difficultjr in assigning more than a subgeneric value to it. Matthew [1901b, p. 303] considers that the mode of occurrence of the ventral valve indicates a difference from Acrotreta, but in the large collection made by Loper the ventral valve of AcrotJiyra hes on the long side of the cone, the aperture being up; tliis is the position the shell would take in settling down on the bottom when the animal was out of the shell and the dorsal valve detached. I have found hundreds of specimens of the ventral valve of Acrotreta idalioensis Walcott and A. attenuata Meek lying on the upper surface of layers of limestone in situ, in just the same positions as those taken by Acrothyra proavia (Matthew) . Four species of the genus are known to me: Acrothyra proavia (Matthew), 4- signata Matthew, A. sera (Matthew), and A. minor Walcott. Matthew [1902a, pp. 381-390] has described a number of varieties of the two Acadian species. In the case of the varieties of A. proavia I find that there is such a gradation of form and character between the varieties that they are of little value. In A. signata the varieties prima and orta are apparently distinctive. After a thorough comparison of Matthew's types of Acrothyra signata sera, Acrothyra signata tarda, Acrotreta papiUata and varieties prima and lata, and a large series of specimens from the same locality and stratigraphic horizon, I have identified the four forms as Acrothyra sera. There is such a gradation in size and shape of the visceral area and exterior of the ventral valve that it does not appear practicable to draw lines establishing varieties and species. The gradation of characters between Matthew's Acrothyra signata sera and Ms Acrotreta papiUata also practically brings together Acrothyra and Acrotreta. An attempt is made on Plate LXXX to show some of the gradations in the form of the visceral area (figs. 6d, 6e, 5a, 6f, 6g, 6h, and 6a). Matthew [1902a, p. 381] assigns importance to the stratigraphic position of the specimens he has referred to species and varieties. TMs does not appear to hold good in the large collec- tions made by Loper. Most of the varieties in form and robustness occur at the horizon of Acrothyra sera and those assigned to A. proavia at its horizon. Tliis makes it difficult to give the same importance to the variations that Matthew [1902a, pp. 381-390] does in liis descriptions. The latter are presented in great detail and should be consulted by those interested in this genus or in the Acrotretidse. Matthew [1901c, pp. 93-107] has made some most interesting and suggestive observations on the resemblance of the more elongated forms of Acrothyra to some species of Hyolithes, sugges- tions to which the student of the Brachiopoda should give careful consideration. A A' FiGXJRE 59. — AcrothijTa minoT ACROTRETIDiE. 717 ACROTHYEA MINOR Walcott. Text figure 59; Plate LXXVI, figures 4, 4a-b. Acroihyra minor Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 303. (Characterized as below as a new species.) This species differs from others referred to the genus by its broad form and very strong vascular sinuses. The elevated callus between the sinuses is liigh and oval ui outline, some- what like that of Acrotreta inflata (Matthew). . It may be that this species belongs to a different genus, but -wdth the material available for study it is referred to Acroihyra on account of its low overhanging false area and elongate visceral area. Formation and locality.— Middle Cambrian: (5b and 54s) o Dark blue-gray Langston limestone |l\'alcott, 1908f, p. 198], just above the Cambrian quartzitic sandstones, north side _ of Twomile Canyon, near its mouth, 2 miles (3.2 km.) southeast of Malade, Oneida County, "'"wrieo'tt. "A',A'"Ex'terior Idaho. and side Adews of a ven- tral valve from Locality AcEOTHYRA PROAViA (Matthew). f*''.'"'?.* iTif/f ^ ' km.) southeast of Malade, Idaho (U. S. Nat. Mus. Plate LXXV, figure 3; Plate LXXVI, figures 3, 3a-u. Cat. No. 52051). Acrotreta proavia JIatthew, 1899. Bull. Nat. Hist. Soc. New Brunswick, vol. 4, pt. 3, No. 19, p. 203, PI. Ill, figs. 2a-f. (Described and discussed as a new species.) Acrothyra proavia prima Matthew, 1901, idem, vol. 4, pt. 4, No. 19, figs. 1-6, p. 303. (No mention of this species is made in the text, which is a description of the genus Acroihyra, but the variety is figured for the first time. The specimen represented by fig. 1 is redrawn in this monograph, PL LXXVI, fig. 3.) A.crothyra proavia AIatthew, 1902, idem, vol. 4, pt. 5, No. 20, pp. 386-388, PL XIV, figs. 2a-g and 3a-f. (Described and discussed. Figs. 2a-f are copied from Matthew, 1899, PL III, figs. 2a-f.) Acrothyra proavia prima Matthew, 1902, idem, p. 389, PL XIV, figs. 4a-f. (Described. Figs. 4a-f are copied from Matthew, 1901b, figs. 1-6, p. 303.) Acrothyra proavia crassa Matthew, 1902, idem, pp. 389-390, PL XIV, figs. 5a-c. (Described and discussed as a new variety.) Acrothyra proavia Matthew, 1903, Geol. Survey Canada, Kept. Cambrian Rocks Cape Breton, pp. 53-55, 57, and 59. (Notes on orientation of shells.) Acrothyra proavia prima Matthew, 1903, idem, p. 58. (Notes on orientation of shells.) Acrothyra proavia prima Matthew, 19D3, idem, figs. 1-6, p. 86. (Figs. 1-6 are copied from Matthew, 1901b, figs. 1-6, p. 303.) Acrothyra proavia prima iU-TTHEW, 1903, idem, p. 93, PL II, figs. 4a-f . (Text and figures copied from Matthew, 1902a, p. 389, PL XIV, figs. 4a-f.) Acrothyra proavia crassa Matthew, 1903, idem, p. 94, PL II, figs. 5a-c. (Text and flgiu:es copied from Matthew, 1902a, pp. 389-390, PL XIV, figs. 5a-c.) The generic description is founded on this species and gives all of its principal characters. Matthew refers to several varieties of this species and [1901b, p. 303, and 1902a, p. 389] names two of them, prima and crassa. Loper's collection shows a great variation in the form and out- line of the valves, particularly the ventral, that appears to include the varieties described by Matthew. The tj^pical form of A. proavia is illustrated by Plate LXXVI, figures 3a, 3b, and 3c; the variety prima by figure 3, and the variety crassa by figures 3e and 3f. The gradations in form between the typical form and its varieties may be traced by the figures on the plate, and by a study of the large series of specimens in the collections. The height of the posterior side or false area has been found one-third, one-half, and about tliree-fifths of the length of the anterior slope from the apex to the margin. The wide variation appears to be due very largely to compression and distortion in the sediment. Acrotreta gemmula Matthew occurs in association with tliis species, and this leads to confu- sion of the dorsal valves of the two species unless care be taken to distinguish them. The A. gemmula shells are rare, and the shell is tliinner, which gives less strongly marked interiors, and less convexity to the outer surface. The dorsal valve of Acrothyra proavia is convex, strong, and deeply marked by the grooves made by the main vascular sinuses. a 5b is the type locality. 718 CMIBRIAN BRACHIOPODA. Acrothyra proavia differs from A. signata Matthew, which occurs about 200 feet lower in the strata of the same section, in having usually a narrower, more elongate visceral cavity, and stronger callosit}'. These features, however, vary in specimens of A. 'proavia associated in the same hand specimen of shale. Formation and LOCALiTY.^Middle Camtrian: (3i) Compact, fine-grained, thin-bedded gray sandstone of the Paradoxidcs zone, on McLean Brook, 1 mile (1.6 km.) east of McCodrum Brook and 1.5 miles (2.4 km.) west of Marion Bridge; (13m) sandstones of Division E3f of Matthew's [1903, p. 76] Etcheminian, on Gillis Brook, Indian River; and (344] [Matthew, 1903, p. 91]) Division E3e of JIatthew's Etcheminian, on the highway at V. McPhees; all in eastern Cape Breton, Nova Scotia. (lOp) Sandstone just below the waterfall in Dugald Brook, Division E2b; (lOq) sandstones a little above lOp in Division E2b; (13e) sandstones of Division E2c; (131 and 3441 [IMatthew, 1903, p. 80]) sandy shales of Division E3a; (13n" and 344b [Matthew, 1903, p. 91]) sandstones of Division E3d; (13n') sandstones of Division E3e; (344a [Matthew, 190-2b, p. 422]) sandy shales of Dividon ESc; and (344d [Matthew, 1903, p. 82]) sandy shales of Division E3f; all in Mat- thew's [1903, p. 21] Etcheminian, on Dugald Brook, Indian River, eastern Cape Breton, Nova Scotia. Acrothyra sera (Matthew). Plate LXXX, figures 4, 4a-c, 5, 5a-d, 6, 6a-i, 7, 7a-b, 8?. Acrothyra (signata) sera Matthew, 1902, Bull. Nat. Hist. Soc. New Brunswick, vol. 4, pt. 5, No. 20, pp. 383-384, PI. XIII, figs. 3a-f . (Described and discussed as a new variety. The specimen represented by fig. 3c is redrawn in this monograph, PI. LXXX, fig. 4c.) Acrothyra signata-tarda Matthew, 1902, idem, pp. 384-385, PI. XIV, figs. la-d. (Described and discussed as a new variety.) Acrotreta papillata Matthew, 1902, idem, pp. 390-391, PL XV, figs. 2a-f . (Described as a new species. In the descrip- tion of PL XV the legend for figs, la-c appears as the legend for figs. 2a-c, and the legend for figs. 2a-f as the legend for figs, la-f ; the specimens represented by figs, la-c (on the plate) are referred to Acrotreta papillata prima; and the specimens represented by figs. 2a-f (on the plate) are referred to Acrotreta papillata. The description of plate is in error, the correct reference being as given in this synonymy. The specimen represented by figs. 2a and 2b is redrawn in this monograph, PL LXXX, figs. 6 and 6'. Acrotreta papiUata var. Matthew, 1902, idem, p. 391, PL XV, figs. 3a-c. (Described. The varietal name lata is given to this form in the description of PL XV.) Acrotreta papellata-prima Matthew, 1902, idem, pp. 391-392, PL XV, figs. la-c. (Described and discussed as a new variety. The thu-d reference explains error in description of plate.) Acrothyra signata sera Matthew, 1903, Geol. Survey Canada, Rept. Cambrian Rocks Cape Breton, p. 56. (Notes on the orientation of the shells.) Acrotreta papiUata- prima Matthew, 1903, idem, pp. 73-74, PL III, figs. la-c. (Mentioned as a new variety, but copies the original text and figm'es, Matthew, 1902a, pp. 391-392, PL XV, figs. la-c. The same error occurs in the description of PI. Ill as occurred in the description of PL XV; see the third reference.) Acrothyra signata sera Matthew, 1903, idem, pp. 87-88, PL I, figs. 3a-f . (Text and figiu-es copied from Matthew, 1902a, pp. 3B3-384, PL XIII, figs. 3a-f.) Acrothyra signata-tarda Matthew, 1903, idem, p. 89, PL II, figs. la-d. (Text and figures copied from Matthew, 1902a, pp. 384-385, PL XIV, figs, la-d.) Acrotreta papillata Matthew, 1903, idem, p. 95, PL III, figs. 2a-f . (Text and figures copied from Matthew, 1902a, pp. 390-391, PL XV, figs. 2a-f . The same error occurs in the description of PL III as occurred in the description of PL XV; see the thu-d reference.) Acrotreta papillata lata Matthew, 1903, idem, pp. 95-96, PL III, figs. 3a-c. (Text and figures copied from Matthew, 1902a, p. 391, PL XV, figs. 3a-c.) Acrothyra sera differs from A. signata in the form of the visceral area and callosity, straighter and nearly vertical posterior side. It is usually more elongate. Matthew [1902a, p. 383] placed it as a variety of A. signata, but its characters appear to justify giving it the rank of a species. A gradation in length, breadth, depth, and outline of the ventral valve and its visceral area is found in specimens from the same bed of rock, that bring together Acrothyra signata sera and tarda and Acrotreta papillata and its varieties lata and prima. Matthew [1902a, pp. 383-385, 390-392] based the above-mentioned species and varieties on differences in form of the ventral valve and its visceral cavity and callosity. With his type specimens before me, and the large series of specimens collected by Loper from Matthew's Division 1, assise d, and from Division 2, between assise a and b, it is impossible for me to consider that more than one variable species is represented. As the name sera is first in order in the original publication, it is retained for the species. Also see notes under genus Acrothyra, pages 715-716. ACROTRETIDiE. 719 Formation and locality. — Middle Cambrian: (lOp') Sandstone 0.25 mile (0.4 km.) from the lower bridge on Gregwa Brook, Indian River; (lOp") sandstone on the small brook on the hill between the bridge over Indian River and McPhees Brook; (13k) shales of Matthew's [1903, p. 15] Coldbrook, above the great fall in Dugald Brook, Indian River; and (344e [Matthew, 1903, p. 78]) shales of Division Eld of Matthew's [1903, pp. 28 and 29] Etcheminian, on Boundary Brook, eastern side of the Escasonie Indian Reservation; all in eastern Cape Breton. (344g [Matthew, 1903, p. 77]) Shales of Division Elc; (13t") sandstones of Divisions Elc and Eld; (13f) sandstones 20 feet (6 m.) above Division E2a; (13d') sandstones opposite the third waterfall in Dugald Brook, between Divisions E2a and E2b; (lOp) sandstones just below the waterfall in Division E2b; and (13e) sandstones of Division E2c; all in Matthew's [1903, p. 21] Etcheminian, on Dugald Brook, Indian River, eastern Cape Breton, Nova Scotia. Shells somewhat doubtfully referred to Acrothyra sera occur at the following localities : Middle Cambrian: (13p) Sandstones 40 feet (12.2 m.) above Division E2a; and (13p') sandstones 45 feet (13.6 m.) above Division E2a; both in Matthew's [1903, p. 21] Etcheminian, on Dugald Brook, Indian River, eastern Cape Breton, Nova Scotia. AcEOTHYEA siGNATA Matthew. Plate LXXX, figures 1, la-d. Acrothyra signata Matthew, 1902, Bull. Nat. Hist. Soc. New Brunswick, vol. 4, pt. 5, No. 20, pp. 381-382, PI. XIII, figs. 2a-e. (Described and discussed as a new species, see below for copy of the greater part. The specimens represented by figs. 2b and 2c are redrawn in this monograph, PL LXXX, figs. 1 and Id, respectively.) Acrothyra signata Matthew, 1903, Geol. Survey Canada, Rept. Cambrian Rocks Cape Breton, p. 87, PL I, figs. 2a-e. (Text and figm-es copied fi-om preceding reference.) Matthew's description [1902a, p. 381] of the interior of the two valves is as follows: There is a strong narrow callus, one-third of the length of the valve, bounded by a raised ridge at the sides and in front; at the front of this callus is an oval pit, from which a gi-oove runs backward nearly to the apex of the shell, where it is supposed to connect with the foramen. Outside the callus, on each side, near the margin of the valve, are len- ticular marks of the lateral muscles. About the middle of the valve the position of the anterior adductors is indicated by a faint impression of the lozenge or "heart-shaped" depression. * * * * * * This shows a sharp, thin, median septum for half of the length of the valve. This ridge is broader and more distinct at the front; at each side are lateral obscure ridges, diverging from the umbo. Outside of these ridges are the lenticular imprints of the lateral muscles. The only modification to be made is in leaving out the word "narrow" before "callus" in the description of the ventral valve. The callosity is strong and relatively broad. Among the type specimens received from Doctor Matthew one ventral valve is elongate, like the type figured by him. Two other ventral valves are shorter, like our figures 1, la-b. The dorsal valves are similar in the material received from Doctor Matthew and that Ulustrated by him, and in the collection made by Mr. S. Ward Loper. A. signata differs from A. proavia (Matthew) in the less elongate, narrow visceral cavity and apical callosity of the ventral valve. It occurs at about 200 feet lower in the strata, accord- ing to Matthew, who [1903, pp. 23-27] gives a detailed section of the beds and lists of fossils occurring at each faunal zone. Matthew [1902a, p. 382] found this species in his Division Elb. Loper collected it from Matthew's Division Eld; also in abundance between Divisions E2a and E2b on Dugald Brook. Formation and locality. — Middle Cambrian: (13t) Sandstones at the base of Division Elb; (344k [Mattheio, 1903, p. 77]) sandstones of Division Elb; (13f ) sandstones of Divisions Elc and Eld; (13d') sandstones opposite the third waterfall in Dugald Brook, between Divisions E2a and E2b; (lOp) sandstones just below the waterfall in Divi- sion E2b; all in Matthew's [1903, p. 21] Etcheminian, Dugald Brook, Indian River, eastern Cape Breton, Nova Scotia. ACEOTHTKA SIGNATA ORTA MatthcW. Plate LXXX, figures 3, 3a-b. Acrothyra signata orta Matthew, 1902, Bull. Nat. Hist. Soc. New Brunswick, vol. 4, pt. 5, No. 20, pp. 385-386, PI. XIII, figs. 4a-f. (Described and discussed as a new variety. The specimens represented by figs. 4a and 4c are redrawn in this monograph, PL LXXX, figs. 3a and 3b, respectively.) Acrothyra signata orta Matthew, 1903, Geol. Sm-vey Canada, Rept. Cambrian Rocks Cape Breton, pp. 89-90, PL I, figs. 4a-f . (Text and figures copied from the preceding reference.) A. signata orta differs from A. signata Matthew in its more elongate form and narrow visceral area, characters that place the variety near A. proavia (Matthew). Its shorter visceral area distinguishes it from A. proavia. In the absence of specimens showing the interior of the ventral valve there is no way of distinguishing A. proavia from A. signata orta. 720 CAMBRIAN BRACHIOPODA. Formation and locality.— Middle Cambrian: (13d") Sandstones 10 feet (3 m.) below Division E2a; (lOp) sandstones just below the waterfall in Division E2b; and (3441 [Mattheiv, 1903, p. 90]) sandstones of Division E2c; all in Matthew's [1903, p. 21] Etcheminian, Dugald Brook, Indian River, eastern Cape Breton, Nova Scotia. ACROTHYEA SIGNATA PRIMA Matthew. Plate LXXX, figures 2, 2a-b. Acrothyra signata prima Matthew, 1902, Bull. Nat. Hist. Soc. New Brunswick, vol. 4, pt. 5, No. 20, pp. 382-383, PI. XIII, figs. la-g. (Described and discussed as a new variety. The specimens represented by figs, lb and Ic are redrawn in this monograph, PI. LXXX, figs. 2 and 2b, respectively.) Acrothyra signata prima Matthew, 1903, Geol. Survey Canada, Kept. Cambrian Rocks Cape Breton, p. 73, PI. I, figs. la-g. (Text and figures copied from the preceding reference.) The material representing this shell is in poor condition, but sufficient evidence of the form and interior characters of the ventral valve is preserved to show that it differs from A. signata Matthew in its subconical form, and in the shorter and proportionally broader visceral area. It is very difficult to find any clearly defined distinction between some specimens of Acrothyra sera Matthew and A. signata frima, as the latter shows ventral valves quite as regu- larly conical as the former. One of Matthew's type specimens shows a much higher apex on the ventral valve than his figure 3c [1903, PI. I]; another with the apex broken off shows a cast of the visceral cavity much like that in Plate LXXX, figure la {A. signata Matthew). Matthew [1902a, p. 383] found the types of this species in a fine gray shale interbedded in the volcanic beds. The associated fossils clearly indicate that the fauna is essentially the same as that which follows higher in the strata. Formation and locality. — Middle Cambrian: (13k) "Shales of Matthew's [1903, p. 15] Coldbrook, above the great waterfall in Dugald Brook, Indian River, Cape Breton, Nova Scotia. Genus DISCINOPSIS Matthew. 6 [oidKoc, quoit; and JitS, face.] Discinopsis (Matthew MS.) Hall and Clarke, 1892, Eleventh Ann. Rept. State Geologist New York for 1891, pp. 250-251. (Described.) Discinopsis Matthew, Hall and Clarke, 1892, Forty-fifth Ann. Rept. New York State Museum for 1891, pp. 566-567- (Copy of preceding reference.) Discinopsis Matthew, Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, pp. 105-106. (De- scribed and discussed as a new genus.) Discinopsis Matthew, Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 4, PL XI, and pp. 142 and 146. (Classifi- cation of genus.) All that is known of this genus is incorporated under the description of the type species. Type. — Acrotreta? gulielmi Matthew. Discinopsis gulielmi (Matthew). Plate LXXXII, figures 5, 5a-c. Acrotretaf gulielmi Matthew, 1886, Trans. Roy. Soc. Canada for 1885, 1st ser., vol. 3, sec. 4, No. 4, pp. 37-39, PI. V, figs. 14, 14a-e. (Described and discussed as a new species; see below for copy. The specimen represented by figs. 14c and 14d is redrawn in this monograph, PI. LXXXII, fig. 5. Figs. 5a-c of this monograph are drawn from specimens in the type material, but none of them can be identified with Matthew's figures.) Discinopsis gulielmi (Matthew), Hall and Clarke, 1892, Eleventh Ann. Rept. State Geologist New York for 1891, PI. Ill, figs. 20 and 21. (Fig. 20 is drawn from the specimen figured by Matthew, 1886, PL V, figs. 14c and 14d. Fig. 21 is drawn from one of Matthew's type specimens, and the same specimen is redrawn in this mono- graph, PL LXXXII, fig. 5a, but the specimen can not be identified with any of Matthew's figures.) Discinopsis gulielmi (Matthew), Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, p. 105, PL III, figs. 20-24. (Discussed. Figs. 20 and 21 are copied from figs. 20 and 21 of the preceding reference. The remaining figures are drawn from specimens in Matthew's type material. Figs. 21, 22, and 23 represent specimens which are redrawn in this monograph, PL LXXXII, figs. 5a (=21 and 22) and 5c (=23), but it is impossible to identify the specimens with Matthew's figures.) The original description by Matthew follows: Shell subcircular in outline. Surface depressed-conical, apices eccentric, not marginal. Pedicle valve with the apex truncated by a circular foraminal aperture (?). The interior of this valve is characterized by a pair of deep, a 13k is the type locality, though the specimens represented by that number in the United States National Museum collections were collected later than the type specimens. b Prioi to the definition of the genus Discinopsis the type species was referred to Acrotretaf [Matthew, 18SG, p. 37]. ACKOTRETID^. 721 diverging furrows, passing forward from the beak or internal foraminal opening, in broad curves which converge toward the anterior margin but without meeting. These furrows inclose a thickened and somewhat elevated central area, which, in the subumbonal region, is apparently free, projecting for a short distance, like a narrow, triangular shelf, beneath which the foramen probably opened. The interior opening of the foramen is, however, not apparent on any of the specimens examined, for, as usually preserved, the matrix has adhered to this subapical cavity, and in a single example only is the shelf -like character of the median area distinctly demonstrated. A faint longitudinal ridge passes from the apex of the shelf to the anterior margin, but no other markings are discernible on the interior- except faint radiating or slightly undulating, probably vascular, lines. The interior of the brachial valve, as far as known, shows no other characters than the radiating lines, which appear to belong to the ornamentation of the outer surface. Shell substance tenuous, apparently corneous. External surface covered with more or less prominent, some- times lamellose concentric growth lines, crossed by fine, gently curved, radiating stri^ which are usually more promi- nent when the concentric lines are exfoliated. Observations. — The interior of the ventral valve of this species is not unhke that of Acro- ihele. (Compare PL LXXXII, fig. 5a, with PI. LX, figs. If and 2.) It is not like that of Acrotreta sagittalis taconica (PI. LXXI). I have not been able to find an apical shelf in the type specimens or other specimens. The material representing D. gulielmi is compressed in the shale, so that the apical callosity is more or less compressed and distorted. The dorsal valve, with its eccentric apex, is unhke Acrothele or any other of the genera of the Acrotretidse. With our present information, Disdnopsis is referred to the Acrotretidse and nearest to Acroihyra. I have not discussed the description and conclusions of Matthew [1886, p. 37], as neither Hall and Clarke nor I could find the muscle scars described and illustrated by him. The student should carefully read Matthew's description and observations, as there is much oppor- tunity for difference of opinion of minute shells compressed in shale. Formation and locality. — Middle Cambrian: (301g [Matthew, 1886, p. 39]) Sandstones of Division Ic of Mat- thew; (3O8I1) shales of Division Icl; and (301w) shales of Division lc2; all at Portland (now part of the city of St. John), St. John County, New Brunswick. DisciNOPSis? suLCATus Walcott. Plate LXXXII, figure 6. Craniella f? sp., Walcott, 1905, Proc. U. S. Nat. Mus., vol. 29, pp. 4 and 6. (Listed.) Disdnopsis sulcatus Walcott, 1906, idem, vol. 30, pp. 568-569. (Described and discussed as below as a new species.) This species is based upon the cast of the interior of a smaU ventral valve that in its interior markings closely approaches the interior of the ventral valve of Disdnopsis gulielmi (Matthew). The interior cast shows that the ventral valve was subcircular in outhne, moderately convex, and with the apex probably perforated by a small, circular, foraminal aperture. In front of the cast of the base of the foraminal aperture there is a broad depression that extends to the front margin; on each side of the central depression an elongate, slightly depressed area extends forward and outward from near the base of the cast of -the foraminal aperture, along the ridge on each side of the median depression; back of the base of the foraminal aper- ture there is a narrow, short, arched furrow that indicates the presence of a corresponding ridge on the interior of the shell. No other markings are shown on the cast, except the faint outUne of what may have been the visceral area, on the median hne in front of the base of the foraminal aperture and between the broad vascular sinuses. Observations. — This species is referred to the genus Disdnopsis as the result of comparison with specimens of the interior of a ventral valve of D. gulielmi (Matthew). One interior of the latter species has scars much hke those shown in D.P sulcatus. This form has a sulcate ventral valve, hence the specific name. Formation and locality. — Upper Cambrian: (C66) Lower part of the Chaumitien limestone, 25 feet below the top of Pagoda Hill [Blackwelder, 1907a, p. 42 (part of last list of fossils)], 1 mile (1.6 km.) west of Tsinan, Shantung, China. 62667°— VOL 51, pt 1—12 46 ■ 722 CAMBRIAN BRACHIOPODA. Superfamily DISCINACEA Waagen. Family DISCINID^ Gray. ' Genus ORBICULOIDEA d'Orbigny. For synonymy, description, and discussion of this genus the student is referred to the memoir of Hall and Clarke [lS92c, pp. 120-137]. The genus has been recently classified [Wal- cott, 1908e, PI. XI, and pp. 142 and 147]. Two Upper Cambrian species are tentatively referred to the genus: 0. varians (Barrande) and 0. contraria (Barrande), and one Mddle Cambrian species, 0. pileolus (Salter). Orbiculoidea contearia (Barrande). Plate LXXXI, figure 9. Discina contraria Barrande, 1868, Faune silurienne des environs de Hof, en Baviere, p. 104, fig. 72. (Described in French as a new species; see below for translation. Fig. 72 is copied in this monograph, PI. LXXXI, fig. 9.) Genre? sp. nehulosa Barrande, 1868, idem, pp. 105-106, fig. 69. (Described and discussed in French as a new species.) Disaina contraria Barrande, 1868, Neues Jahrb. ftlr Mineralogie for 1868, pp. 692-693, unnumbered plate, fig. 72. (Copied from Barrande, 1868a, p. 104, fig. 72.) Genre? sp. nebulosa Barrande, 1868, idem, pp. 693-694, unnumbered plate, fig. 69. (Copied from Barrande, 1868a, pp. 105-106, fig. 69.) Discina contraria Barrande, Pompeckj, 1896, Tremadoc Fossilien bei Hof, p. 4. (Occurrence mentioned in German.) The original description by Barrande follows: This form, decidedly transverse, contrasts with the preceding, which is elongated. It also forms an ellipse, which, however, is truncated on the larger side. The shell presents only a slight bulge. The summit is placed somewhat beyond the center, going toward the truncated edge. Starting from the summit, the siu-face forms an inclined plane up to the contour. The perforation is linear and very short. The shell, partly preserved, presents very marked con- centric strife, at unequal intervals. Longitudinal diameter, 6 mm.; transverse diameter, 9 mm. Ohservations. — Pompeckj [1896a, p. 4] states that this species was found much more frequently than 0. varians (Barrande), and that rather convex shells, 10 mm. long and 12 mm. broad, were not rare. The generic relation of this species is doubtful. It is not Discina, nor from the evidence available can it be referred without question to Orhiculoidea. Pompeckj, in reply to my inquiry as to whether he had identified "Genre? nehulosa" of Barrande, wrote as foUows under date of August 7, 1906: As to the nebulosa by Barrande (Faune silurienne des Environs de Hof, fig. 69) I find in notes made on the Barrande originals (in the collection of the Oberbergamt-Munich) that "nebulosa" is to be identified with Barrande's Discina contraria, 1. c, figure 72. Both are pedicle valves of Disdna with the characteristic perforation of that family below the apex. Both figures are incorrectly given. The two sharp lines radiating from the apex in figure 69 are only caused by pressiue of the somewhat high shell, and in figiue 72 the concentric stride are indeed much more delicate than in the figures which represent an interior cast only, with bits of the shell in the upper part, i.e., near the hinge line. Exact determination of these shells is very difficult; most of them (1 saw more than a hundred) are compressed, crumpled, deformed, very seldom the apical region is clearly to be seen; shell rarely preserved; but there is indeed no doubt that they must belong to the Discinidfe on account of the "Schlitz " below the apex. There is no sharp differ- ence between the roimded form, named Discina varians by Barrande, and between the larger and wider form, D. contraria, or nebulosa. Formation and locality. — Passage beds between the Upper Cambrian and the Ordovician: (303c [Barrande, lS6Sa, p. 104]) suburbs of Hof ; and (303f [Pompeckj, 1896a, pp. 7 and 8]) railway cut near Schellenberg, a little distance back of the railway station at Neuhof, near Hof; both in Bavaria, Germany. Orbiculoidea pileolus (Hicks MS.) (Salter). Plate LXXXI, figures 11, 11a. Discina -pileolus (Hicks MS.) Salter, 1866, Kept. British Assoc. Adv. Sci. for 1865, p. 285. (Mentioned.) Discina pileolus Salter, Davidson, 1868, Geol. Mag., vol. 5, pp. 312-313, PI. XVI, figs. 11-12. (Described and dis- cussed; see p. 723 for copy of description. Figs. 11a and 12a are copied in this monograph, PL LXXXI, figs. 11 and 11a, respectively.) DISCINID^. 723 Discina pileolus Salter, Davidson, 1871, British Fossil BracMopoda, vol. 3, pt. 7, No. 4, p. 344, PI. XLIX, figs. 41^2. (Original description, Davidson, 1868, pp. 312-313, copied. Figs. 41 and 42 are copied from Davidson, PI. XVI, figs. 12 and 11, respectively.) Not Discina pileolws? Hicks, 1871, Quart. Jour. Geol. Soc. London, vol. 27, pt. 1, PI. XV, figs. 12 and 12a. (Referred in this monograph to Stenotheca.) Orbiculoidea pileolus (Salter), HALLand Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, p. 137. (Changes generic reference.) The original description by Davidson [1868, p. 312], follows: Shell very small, circular or slightly longitudinal oval, rather broader anteriorly; about two and a half lines in length and a little less in breadth. Dorsal valve conical. Ventral valve slightly convex, depressed near the margin; vertex in both valves at a short distance from the center, as also the foramen (?) in the ventral valve. Surface marked with concentric lines, which are more strongly marked in the ventral valve. Interior not known. I have not been able to secure specimens of this interesting shell, so can not add any per- sonal observations upon it. Hall and Clarke [1892c, p. 137] suggest its I'eference to Orbiculoidea and ia this, from our present information, I concur. As they have pointed out, it is the oldest representative of the genus. Hicks [1871, PL XV, fig. 12] illustrates a depressed conical shell from the "Red" beds at the base of the "Purple" rocks, about 3,000 feet below the base of the Middle Cambrian "Menevian group" as "Discina pileolus." Later [1881, p. 297] he calls the species "Discina cserfaiensis." To me the shell is more suggestive of the gastropod genus Stenotheca than of a brachiopod and until I can obtain better material it will be so referred. Formation and locality. — Middle Cambrian: (318e) Lower portion of the Menevian at Camlan, North Wales; (318d) sandstones in the middle portion of the Menevian at Porth-y-rhaw , St. Davids, South Wales; (318p) sandstones in the middle portion of the' Menevian at Ninewells, near St. Davids, South Wales; (318q) yellowish-gray beds in the Harlech group, on the road between Solva and Whitechurch, St. Davids, South Wales; and (318r) sandstones in the middle portion of the Menevian at Solva Harbor, St. Davids, South Wales; all [Davidson, 1871, pp. 344 and 345] in Wales. Orbiculoidea varians (Barrande). Plate LXXXI, figure 8. Discina varians Barrande, 1868, Faune sUurienne des environs de Hof, en Bavifere, pp. 103-104, fig. 71, (De. scribed in French as a new species. Fig. 71 is copied in this monograph, PI. LXXXI, fig. 8.) Discina varians Barrande, 1868, Neues Jahrb. filr Mineralogie for 1868, p. 692, unnumbered plate, fig. 71. (Copy of preceding reference.) Discina varians Barrande, Pompeckj, 1896, Tremadoc FossUien bei Hof, p. 4. (Occurrence mentioned in German.) The original description by Barrande follows: The form of this species is always elongated, but in proportions varying somewhat with the individuals. The 'surface is slightly arched. The summit is somewhat beyond the center of the figure, which is an ellipse, slightly truncated at the small end near the perforation. The perforation is linear and less than 1 mm. in length. The frag- ments of the shell that remain present traces of fine concentric strise. The imperforate valve has not been observed. Length, 6 mm.; breadth, 5 mm. Observations. — I am not able to add to the above description. It is evident that the species is not a Discina, as that genus is now understood, but with only a single figure and the above description it is not practicable to make a satisfactory generic reference. The subcentral apex with the elongate slit back of it, is more suggestive of Orbiculoidea than any other genus of the lower Paleozoic fauna. Formation and locality. — Passage beds between the Upper Cambrian and the Ordovician: (303c [Barrande, 1868a, p. 103]) suburbs of Hof ; and (303f [Pompeckj, 1896a, pp. 7 and 8]) railway cut near Schellenberg, a little distance back of the railway station at Neuhof, near Hof; both in Bavaria, Germany. 724 CAMBRIAN BRACHIOPODA. Superfamily CRANIACEA Waagen. FamUy CRANIID^ King. Genus PHILHEDBA Koken.o I Philhedra Koken, 1889, Neues Jahrb. fur Mineralogie, Beilage-Band 6, Hft. 3, p. 465. (Discussed in German as a new genus.) Philhedra Kol^en, von Huene, 1899, Neues Jahrb. fiir Mineralogie, Bd. 1, pp. 146-147. (Described and discussed in German. See below for translation of diagnosis.) Philhedra Koken, von Huene, 1899, Verhandl. Russ.-kais. min. Gesell. St. Petersburg, 2d ser., Bd. 36, Lief. 2, pp. 216-218 (list of species referred to Philhedra), and pp. 297-298. (Described and discussed in German.) Philhedra Koken, Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 4, PI. XI, and pp. 142 and 147. (Classification of genus.) The emended diagnosis of the species bj' von Huene follows: Inequivalve, with the flat ventral shell attached. Dorsal shell subconical to bowl-shaped, frequently irregularly bent; the concentric growth lines are mostly crossed by radial ribs or rows of prickles; without limbus. Anterior occlusors larger than posterior occlusors. Type. — Patella rivulosa Kutorga. Von Huene, in Ms memoir on the Silurian Craniidse [1899b, pp. 181-359], redefines the genus Philhedra of Koken, and considers P. Columbiana (Walcott) as its oldest representative. The student who wishes to pursue the study further should read von Huene's memoir on the Silurian Craniidaj [1899b, pp. 181-359] and his "Systematik der Craniaden" [1899a, pp. 138-151]. Philhedra columbiana (Walcott). Plate LXXXl, figure 10. Crania? columbiana Walcott, 1889, Proc. U. S. Nat. Mus. for 1888, vol. 11, p. 441. (Described and discussed as a new species.) Crania? columbiana Walcott, von Huene, 1899, Neues Jahrb. fiir Mineralogie, Bd. 1, p. 141, footnote. (Mentioned.) Philhedra? columbiana (Walcott), von Huene, 1899, Verhandl. Russ.-kais. min. Gesell. St. Petersburg, 2d ser., Bd. 36, Lief. 2, pp. 216 and 298. (Mentioned.) Crania columbiana Walcott, Matthew, 1902, Trans. Roy. Soc. Canada for 1902, 2d ser., vol. 8, sec. 4, No. 3, pp. 108-109. (Copies the original description, Walcott, 1889c, p. 441.) Philhedra columbiana Walcott, 1908, Canadian Alpine Joinn., vol. 1, No. 2, PL I, figs. 5 and 5a. (No text reference. Figs. 5 and 5a are copied in this monograph, PI. LXXXI, figs. 10 and 10', respectively.) Shell small, subcircular, or a little longer than %vide, subconical -with the apex slightly eccentric. Outer surface exfoliated; the inner layer of the shell appears to have been com- posed of a calcareocorneous substance; it is marked by from 40 to 45 fine ribs that radiate from the apex to the margm. Diameter about 2 mm. \¥hen preparing this monograph I carefully examined the original specimen, removed a little of the attached matrix from the outer margins and discovered traces of what appear to be minute spines radiating from the margin. Many collections from the type locality of this species have passed through my hands from 1888 to 1906, but it was not until the summer of 1907 that another specimen was seen, and then only two were found in the Ogygofsis zone of Mount Stephen. These are both crushed and broken specimens of the inner side of the conical valve. There is a striking similarity in appearance between this shell and Crania Ixlia Hall and Clarke [1892c, PL IV h, fig. 1] and other similar forms. The specific name is derived from British Columbia. Formation and locality. — Middle Cambrian: (14s) About 2,300 feet (701 m.) above the Lower Cambrian and 2,700 feet (823 m.) below the Upper Cambrian, in the Ogygopsis zone of the Stephen formation [Walcott, 1908f, p. 210], on the northwest slope of Mount Stephen, above Field on the Canadian Pacific Railway, British Columbia, Canada. a The synonymy for this genus is not complete and does not even give a record of all the genera under which the Cambrian species of Philhedra has been placed; it gives only those references in which the genus is discussed or described. To complete the record for the species taken up in this monograph the following mere references are listed: Crania ? Walcott [18S9c, p. 4-11]. I Crania Matthew [1902c, p. 108]. Orania? von Huene [1899a, p. 141]. I BILLINGSELLID^. 725 Order PROTREMATA Beecher. [7zp6, early; and xp^pa, perforation.] Superfamily ORTHACEA Walcott and Schuchert. FamUy BILLINGSELLID^E Sclnich.ert. SubfamUy NISUSIIN^ Walcott and Sclmcliert. Genus NISUSIA Walcott.a Billingsella Hall and Clarke (in part), 1892, Nat. Hist. New York, Paleontology, vol. 8, pp. 230-231. (Described and discussed as a new genus. As described the genus includes species that are now referred to Nisvsia.) Nisusia Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 247-248. (Described essentially as below as a new genus.) Nisusia Walcott, Grabau and Shimer, 1907, North American Index Fossils, vol. 1, p. 210. (Characterized.) Nisusia Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 4, PL XI, and pp. 142 and 147. (Classification of genus.) Form subquadrate to transverse] j'- semioval. Shell structure dense with a minutely granular groundmass with minute pores penetrating some of the lamellse forming the shell. The pores vary greatly in number and arrangement. Surface with narrow, radiating ribs that support irregularly distributed spines on their crests. Ventral valve elevated and usually much more convex than the dorsal, and in most species a mesial sinus appears on it. Area high, vertical or iaclined backward; delthyrium large and partly closed with a convex deltidium; teeth strong and supported by dental plates that extend outward, also inward, forming on the inside a shallow spondyhum. Dorsal valve moderately convex with only a trace of a median elevation; usually the surface is convex, but it may be sUghtly concave from the umbo to the margins; crura well developed, with the crural plates extended so as to form a shallow cruralium. No traces of a cardinal process have been observed in the dorsal valve. Type. — OrtMsina festinata BUlings. Observations. — A comparison of the area of the ventral valve of Nisusia with that of the same valve in Billingsella shows in each a convex deltidium partly covermg a large trian- gular delthyrium. In Billingsella the upper extremity of the deltidium is perforate and it is probably so in Nisusia, but on this point there is an uncertainty, as no specimen has been found clearty showing the pedicle opening. It may be that the deltidium of Nisusia was per- forate in the younger stages of growth and subsequently filled by shell growth. The strong vascular sinuses of the ventral valve of Billingsella are absent in Nisusia, as well as tha tripartite division of the umbonal cavity. The interiors of the dorsal valves of the two genera show marked differences. The cardinal process is well developed in Billingsella but not in Nisusia. There is a small, shallow cruralium in Nisusia but none in Billingsella. The dorsal valve of Nisusia has a clearly developed cruralium, but not any trace of a cardinal process. The ventral valve of Billingsella shows a tendency to form a spondyhum resting on the interior of the valve, a character unknown in Nisusia. The general form of Nisusia is not unhke that of Billingsella except that its ventral valve has a more erect beak and cardinal area. These comparisons include such species of Billingsella as B. Colorado ensis, B. plicatella, and B. exporrecta, but not B. dice (PI. CI, figs. 8, 8a-c). Of Nisusia, they include N. festinata and some of the subgenus Jamesella, such as N. (J.) perpasta, erecta, and amii. BiUingsella and Nisusia both occur in Lower Cambrian strata, but BillingseUa has its greatest development in the ^Middle Cambrian and Nisusia in the Lower Cambrian. It is not " The synonymy tor this genus does not give a complete record of the various genera under which the species now included in Nisusia were formerly placed; it gives only those references in which the genus is discus.sed or described. To complete the record the following mere generic references are listed: OTihisina de Vemeuil and Barrande [1860, p. 533]. Orthisirta BiUings [1861b, p. 10; 1861c, p. 949; 1862b, p. 105; 1862e, p. 221; 1863, p. 284]. Orthisina Mallada [1875, p. 32]. Orthisina Walcott [18S6b, pp. 120 and 121; 1889e, p. 442; 1891a, p. 613]. Orthisina Tate [1892, p. 185]. Billimjsella Schuchert (1897, p. 168]. Orthisina Matthew [1902c, p. 109]. 726 CAMBKIAN BRACHIOPODA. probable that eithsr genus is directly descendant from the otlaer, but I think that both came from an ancestor that lived in early Lower Cambrian time and that Billingsella is further advanced in its development than Nisusia. NiSUSIA ALBEETA (Walcott). Plate C, figures 3, 3a-d. Orthisina alberta Walcott, 1889, Proc. U. S. Nat. Mus., vol. 11, p. 442. (Described as a new species.) Billingsella alberta (Walcott), Schuchert, 1897, Bull. U. S. Geol. Survey No. 87, p. 158. (Merely changes generic reference.) Orthisina alberta Walcott, Matthew, 1902, Trans. Roy. Soc. Canada, 2d ser., vol. 8, sec. 4, No. 3, p. 109. (Original description, Walcott, 1889c, p. 442, copied.) Nisusia alberta Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 248-249. (Described and discussed essentially as below.) Nisiisia alberta Walcott, 1908, Canadian Alpine Jour., vol. 1, No. 2, p. 245, PI. I, figs. 4 and 4a. (No text reference. Figs. 4 and 4a are copied in this monograph, PI. C, figs. 3c and 3d, respectively.) Shell transversely suboval, front broadly rounded; the straight hinge line is shorter than the full width of the valves. Surface of shell with numerous radiating ribs that increase by interpolation; on a shell 19 mm. in width there are four ribs near the front margin in a dis- tance of 3 mm. ; the ribs are rather narrow and sharp crested, the interspaces being wider than the ribs. A cast of the outer surface of a shell in siliceous shales shows numerous strong spines irregularly distributed on the ribs very much as in N.festinata (PI. C, fig. 3c). Ventral valve elevated at the umbo and apex in some shells, convex and rounded over toward the area in others; area varying in height in different sheUs, usually elevated and overhanging the hinge line; it is divided by a strong delthyrium that is covered by a convex deltidium of varying length, arched at its front margm and divided by longitudinal lines into tliree parts. Dorsal valve gently convex; area low, and a little inclined over the hinge line; delthyrium broad with a narrow chihdium. Casts of the interior show a broad, well-defined pseudo- crurahum and just in advance of it the adductor muscle scars. Observations. — Tliis species recaUs at once Nisusia festinata by its elevated ventral valve and spinose surface; it differs from it by its transversely suboval outline, large umbonal muscle cavity (pseudocrurahum) in the dorsal valve and sharp crested ribs. Nisusia (Jamesella) perpasta has the general form and surface characters of tliis species. A marked difference is caused by N. alberta occurring in a siliceous shaly matrix and N. {Jamesella) perpasta as casts in a quartzitic sandstone, and the strong surface spines of N. alberta are sparingly represented on the latter. A shell that appears to be identical with this species occurs at about 1,600 feet above the base of the Mddle Cambrian terrane in Utah. The specific name is derived from Alberta, Canada. Formation and locality.— Middle Cambrian: (14s) About 2,300 feet {701 in.) above the Lower Cambrian and 2,700 feet (823 m.) below the Upper Cambrian in the Ogygopsis zone of the Stephen formation [Walcott, 1908f, p. 210], at the "fossil bed," on the northwest slope of Mount Stephen; and (35k) Burgess shale member of the Stephen formation on the west slope of the ridge between Mount Field and Wapta Peak, 1 mile (1.6 km.) northeast of Burgess Pass; both above Field on the Canadian Pacific Railway, British Columbia, Canada. Specimens that probably belong with Nisusia alberta occur at the following locality, together with other specimens that are somewhat doubtfully referred to the species: Middle Cambrian: (54ii) A drift block supposed to have come from a horizon 1,700 feet (518.2 m.) above the Brigham quartzite [Walcott, 1908a, p. 8], found near the mouth of Wasatch Canyon, east of Lake\-iew ranch, 5 miles (8 km.) north of Brigham, Boxelder County, Utah. Specimens that appear to represent a variety of Nisusia alberta occur at the following localities : Middle Cambrian: (57c and 57k) About 2,500 feet (762 m.) above the Lower Cambrian and 2,475 feet (754 m.) below the Upper Cambrian in the limestone forming 1 of the Stephen formation [Walcott, 1908f, p. 209]; and (68z) about 1,875 feet (572 m.) above the Lower Cambrian and 3,100 feet (945 m.) below the Upper Cambrian in the lime- BILLINGSELLID^. 727 stone forming 2b of the Stephen fonnation [Walcott, 1908f, p. 211]; both on Mount Bosworth, north of the Canadian Pacific Railway between Hector and Stephen, on the Continental Divide between British Columbia and Alberta, Canada. (57j) About 2,000 feet (609.6 m.) above the Lower Cambrian in the limestone forming 2 of the Stephen formation [Walcott, 1908c, p. 237 (6)], just east of the "fossil bed," on the northwest slope of Mount Stephen, above Field on the Canadian Pacific Railway, British Columbia, Canada. Lower Cambrian: (58k) Just below the Middle Cambrian in the limestone forming 1 of the Moimt "WTiyte forma- tion. [M'^alcott, 1908c, p. 240 (9)], just above the tunnel; and (58p) drift block of limestone believed to have come from the limestone forming 1 of the Mount Whyte formation [Walcott, 1908c, p. 240 (9)], found near the Canadian Pacific Railway track just west of the tunnel; both 3 miles (4.8 km.) east of Field, British Columbia, Canada. NisusiA COMPTA (Tate). Plate XCVII, figure 14. Orthidna compta Tate, 1892, Trans. Roy. Soc. South Australia, vol. 15, p. 185, PL II, figs. 6 and 6a. (Described as a new species. The specimen represented by figs. 6 and 6a is redrawn in this monograph, PL XCVII, fig. 14.) Form transversely subquadrilateral with the hinge Hne a httle shorter than the greatest width of the shell. Surface of the shell marked by strong, concentric ridges of growth that cause undulations of variable extent, also fine radiating, rounded, depressed ribs that are a Uttle wider than the interstitial furrows. The outer surface is exfohated, but the interior lamellffi of the shell show small, irregularly distributed nodes on the ribs that are considered to be the bases of spines similar to those on the surface of Nisusia festinata (BUlings) (PI. C, fig. 1) and N. alberta (Walcott) (PL C, fig. 3c). The ventral valve, is moderately convex with a low median fold. Area of medium width and projecting slightly backward; it is divided midway by a rather broad, triangular delthyrium that is nearly covered by a convex deltidium; the area and delthyrium are marked by fine transverse lines of growth. Length of valve from beak to incurve of median fold, 6 mm.; greatest width, 9 mm.; length of liinge line, 7 mm. Observations. — This species is represented in the collection before me by a single speci- men. This appears to be a ventral valve, but, unlike the ventral valve of N. festinata (PI. C, figs. 1, la-d), wliich has a median sinus, it has a median fold. The area and convex deltidium are Uke those of the ventral valve of N. festinata. The fine ribs and quadrate form distinguish this species from other species of the genus. Formation and locality. — Middle? Cambrian: (315 [Tate, 1892, p. 185]) Limestone at Curramulka, Yorke Peninsula, South Australia. Nisusia festinata (Billings). Text figure 6, page 299; Plate C, figures 1, la-j, 2, 2a-c. OriJiisina festinata Billings, 1861, Geol. Survey Canada, Paleozoic Fossils, vol. 1, p. 10, figs. 11 and 12. (Described as a new species.) Orthisina festinata Billings, 1861, Report on the Geology of Vermont, vol. 2, p. 949, figs. 350-352. (Text and figures copied from preceding reference.) Orthisina festinata Billings, 1862, Am. Jour. Sci., 2d ser., vol. 33, p. 105. (Discussed.) Ortkisina festinata Billings, 1862, Report on the Economic Geology of Vermont, by Hager, p. 221, figs. 350-352. (Text and figures copied from Billings, 1861b, p. 10, figs. 11 and 12.) Orthisina festinata Billings, 1863, Geol. Survey Canada, Fifteenth Rept. Progress, figs. 289a-c, p. 284. (No text reference. The figures are copied from Billings, 1861b, figs. 11 and 12, p. 10.) Orthisina festinata Billings, Walcott, 1886, Bull. U. S. Geol. Survey No. 30, pp. 120-121, PL VII, figs. 7, 7a-b. (Original description, Billings, 1861b, p. 10, copied. The two specimens represented by figs. 7 and 7a-b are redrawn in this monograph, PL C, figs, la and Ih, respectively.) Orthisina festinata Billings, Walcott, 1891, Tenth Ann. Rept. U. S. Geol. Survey, p. 613, PL LXXII, figs. 7, 7a-b. (Mentioned. The figures are copied from the preceding reference.) Billing sella festinata (Billings), Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, p. 230. (Merely changes generic reference.) Nisusia festinata (Billings), Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 249-251. (Described and discussed essentially as on p. 728.) Nisusia festinata (Billings), Grabau and Shimer, 1907, North American Index Fossils, vol. 1, p. 211, fig. 249, p. 210. (Described. Fig. 249 is copied from Walcott, 1886b, PL VII, figs. 7, 7a-b.) 728 CAMBRIAN BRACHIOPODA. General form subquadrateto transversely semioval, with the cardinal extremities subacute to obtusely angular. Hinge line straight, usually equal to or greater in length than the width of the body of the shell. Shell substance dense, granular, with minute pores arranged in scat- tered radiating lines; none of the pores appear to pass tlurough more than one lamella of the sheU. Surface with narrow, rounded, radiating ribs, that increase by both bifurcation and inter- polation; the ribs are roughened by concentric lines and ridges of growth that arch about the base of strong, acute spines; the spines are located on the ribs, usually just back of a ridge of growth; they are in more or less irregular, concentric rows toward the front of the sliell, but on the central portions they may be scattered without any system of arrangement; each spine is larger at the base, tapering rapidly, and curving gradually backward at about one-half its length. The ventral valve is more or less elevated at the umbo and apex; in some examples it is subpyramidal (PI. C, fig. le), where the height is to the length as 3 to 6, and width 9 mm.; in other shells the proportion is 4 to 11, and width 17 mm.; the slopes from the apex to the mar- gins are nearly straight or slightly convex; the form of the umbo and apex varies from a broad, rounded umbo terminating in a minute beak curving over the area, to an erect, vertical, more or less rounded apex, with a broad base rising abruptly from the elevated umbo; a shallow, rounded, median sinus occurs on most shells, but it is sometimes absent. Area high, and crossed by transverse lines of growth; it is usually inclined over the hinge line, but it may be vertical or inchned forward (fig. le) ; it is divided by a strong delthyrium, which is covered by a convex deltidium that the author of the species, BilHngs, describes [1861c, p. 10] as perforate at the apex." I have not been able to verify this in a large collection of material from various local- ities; casts of the interior of the extended beak indicate but do not prove that there was a perforation; the front edge of the deltidium is arched so as to leave a space of variable height between it and the plane of the hinge line; in three examples the area is divided into three parts by longitudinal lines (PI. C, fig. le"), two of the lines bound the delthyrium, and one on each side corresponds in position to the "flexure" lines in Obolus and Hipparionyx. A cast of the interior of a low ventral valve (PI. C, fig. If) shows a broad delthyrium, strong teeth, and supporting dental plates which are produced on the inside so as to form a short, elevated base (pseudospondylium), and on the outside the plates are continued partly about the space occupied by the points of attachment of the diductor muscles. The dorsal valve is moderately convex at the umbo, sloping gently from there to the margins; usually the slope is convex, but in one example it is slightly concave; area narrow and vertical or slightly inchned over the hinge line ; casts of the interior show the crura, points of attachment of posterior adductor scars (e, PI. C, fig. Ig; see fig. 3a), area of attachment of diductor scars (d', PI. C, figs. Ig, li). Vascular and ovarian markings unknown. Observations. — This shell has a wide geographic distribution. I have collected it at the type locality in the townsliip of Georgia, Vermont; at Bio on the lower St. Lawrence River; and near York, Pennsylvania. The matrix at Bic is a finely gramdar, shghtly arenaceous hme- stone in which the outer form of the shell is well preserved, but the spines are rarely seen. At Swanton and Georgia, Vermont, the shell occurs in siliceous limestone and arenaceous shale, and a cast of the outer surface shows the spines; the material from the finely arenaceous lime- stone at the Emigsville localities, discovered by A. Wanner, of York, Pennsylvania, is the best preserved and affords excellent casts of the interior and exterior of the valves. In all of the localities the variation in the form and elevation of the ventral valve occurs ; specimens of the ventral valve from Bic, Canada, show a shorter deltidium than is usually present. A number of exfoliated shells occur in the collection from the dark-gray compact limestones of eastern New York and are doubtfully referred to this species. a Through the courtesy of Dr. J. F. Whiteaves, of the Geological Survey of Canada, I had the opportunity of examining the types of "Orthisina festinata." None of them preserve the apex of the deltidium, so it is impossible to determine upon what Billings based his statement that the deltidium was perforate. BILLINGSELLID^. 729 Nisusia festinata is a strongly marked species tliat appears to have but one near repre- sentative in form, N. (Jamesella) perpasta. It differs from the latter species in the absence of spinas and in the form of the ventral valve. Formation and locality. — lower Cambrian: (392a) Limestones at L'Anse au Loup, on the north shore of the Straits of Belleisle, Labrador. (2o) Limestone bowlders in conglomerate, on shore at east entrance to harbor at Bic, Rimouski County, Quebec, Canada. (25a) Limestone on the Hall (Donaldson's) farm, 2 miles (3.2 km.) east of Swanton; (319e [Billings, 1861h, p. 10]) limestone '2 miles {3.2 km.) east of Swanton; (25) sandstone just above Parker's quarry, near Georgia; (319m) shales of No. 6 of the section at Parker's quarry [Walcott, 1891b, p. 278], near Georgia; (26) sandstone northeast of the Corman farm buildings, east of Highgate Springs; and (392p) shale on the Jewell farm; all in Franklin County, Vermont. (319w) Limestone 1.25 miles (2 km.) north of Rutland, Rutland County, Vermont. (38a) Limestone 2 miles (3.2 km.) south of North Granville, on the road which turns south from the road running between that village and Truthville, 4 miles (6.4 km.) west-northwest of Granville, Fort Ann quadrangle (U. S. Geol. Survey); and (36) limestone 1 mile (1.6 km.) south of Shushan and 3.5 miles (5.6 km.) north-northeast of Cambridge, » Cambridge quadrangle (U. S. Geol. Survey); both in Washington County, New York. (49) Sandstone on Codorus Creek, 0.125 mile (0.2 km.) below Meyer's mill, near Emigsville; (49a) sandstone on the Liverpool road, south of the schoolhouse, 3 miles (4.8 km.) northwest of York; (346c) shale near York; and (49w) limestone in railroad cut 0.25 mile (0.4 km.) south of Emigsville; all in York County, Pennsylvania. (35f) About 300 feet (91 m.) below the Middle Cambrian in the limestone forming 6 of the Mount Whyte formation [Walcott, 1908c, p. 242 (11)] just above the tunnel on the north shoulder of Mount Stephen, about 3 miles (4.8 km.) east of Field, British Columbia, Canada. (35h) About 375 feet (114 m.) below the Middle Cambrian in the shales of No. 4 of the Mount AMiyte formation [Walcott, 1908f, p. 214], on Mount Bosworth, north of the Canadian Pacific Railway between Hector and Stephen, on the Continental Divide between British Columbia and Alberta, Canada. Nisusia festinata transversa (Walcott). Plate C, figures 4, 4a-b. Orthisina ? transversa Walcott, 1886, Bull. U. S. Geol. Survey No. 30, p. 121, PL VII, figs. 5 and 5a. (Described as below as a new species. The specimens represented by figs. 5 and 5a are redrawn in this monograph, PI. C, figs. 4 and 4a, respectively.) , Orthisina? transversa Walcott, 1891, Tenth Ann. Rept. U. S. Geol. Survey, p. 613, PI. LXXII, figs. 9 and 9a. (No text reference. Figs. 9 and 9a are copied from figs. 5 and 5a, respectively, of the preceding reference.) Nisusia festinata transversa Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 251. (Original description copied as below and species placed as variety of Nisusid festinata.) Shell small, transversely subquadrangular in outline, front broadly rounded, angle formed by the union of the cardinal slopes of the ventral valve 155° to 165°, hinge line straight and as long as the width of the shell. Area of the venti'al valve of moderate height, bent back from the hinge line, divided by a triangular foramen that is higher than wide and covered by a convex deltidium; the area of the dorsal valve is bent back at more than right angles to the hinge line; foramen higher than wide, covered by a deltidium. Surface marked by numerous radiating, fine, even costre, eight in a distance of 3 mm. on the frontal margin of the ventral valve; a few concentric lines of growth cross the radiating costse, but not so as to give them a nodose character. Interior characters unknown. The fine radiating striee and transverse form distinguish this from other described species known to me. Format, on and locality. — Lower Cambrian : (25) Sandstone just above Parker's quarry, near Georgia; (319m) shales of No. 6 of the section at Parker's quarry [Walcott, 1891b, p. 278], near Georgia; and (25a) limestone on the Hal) (Donaldson's) farm, 2 miles (3.2 km.) east of Swanton; both in Franklin County, Vermont. Nisusia rara Walcott. Text figure 60, page 730. NisvMa rara Walcott (in part), 1908, Smithsonian Misc. Coll., vol. 53, No. 3, p. 97, PI. IX, fig. 13a (not fig. 13, which represents a specimen of Eoorthis thyone). (Characterized and discussed as below as a new species. Fig. 13a is copied in this monograph as fig. 60, p. 730.) The ventral valve of this specie.^ has the same general form as that of Nisusia festinata (Billings) (PI. C, figs. Id and le) except that it has a very strong and deep median sinus and 730 CAMBRIAN BRACHIOPODA. is i^ore transverse; the delthyi'ium is also larger. Nisusia rara occurs at the same stratigraphic horizon as Nisusia alberta (Walcott), but it differs from the latter in having a larger delthyrium and a strong and ileep median sinus. The surface of N. rara is marked by rounded radiating ribs that increase by interpolation and bifurcation; small nodes on some of the ribs indicate the presence of spines on the outer surface. A portion of a convex deltidium is shown that has the outer portion broken away. The tA'pe specimen has a length of S mm.; width, 16 mm. Formation and locality. — Middle Cambrian : (55c) Spence shale member of the Ute limestone |l\''alcott, 1908a, p. 8], about 50 feet (15.2 m.) above the Brigham quartzite and 2,755 feet (839.7 m.) below the Upper Cambrian, in a ravine running up into Danish Flat from Mill Canyon, about 6 miles (9.6 km.) west- southwest of Liberty and 15 miles (24.2 km.) west of Montpelier, Bear Lake County, ^ Idaho. \ j Nisusia? vaticina (de Verneuil and Barrande). ■^^^^ Orthisina vaticina de Verneuil and Barrande [not Salter MS.], 1860, Bull. Soc. FIGURE 60 -if «««ara™ Walcott ,^ YTS^nce, 2d ser., vol. 17, pp. 533-535, PL VIII, figs. 8, 8a-d. (Described valve (U. s. Nat. Mus. Cat. No. and discussed in French as a new species; see below for translation. Figs. 8, 5229oa, labeled 52295b [Walcott, 8b-c are copied in this monograph, PL XCVII, figs. 3, 8a-b, respectively.) ■ iQOSd, p. 123] by error)." Orthisina vaticina de Verneuil and Barrande, Mallada, 1875, Bol. Com. Mapa Geologico The specimen represented is Espana, tome 2, p. 32. (Mentioned.) from Locality 55c, Middle Cambrian Spence shale, near Liberty, Idaho. The Original description by de Vcmeuil and Barrande follows: The figure is copied from Walcott [I908d, PI. IX, fig. 13a]. Shell subquadrangular, slightly emarginate below the lateral extremities. Length equal to three-fourths of the breadth. Hinge ridge somewhat shorter than the greatest width of the shell. Ventral valve twice as thick as the dorsal, area double in height. Triangular opening on each of the valves, covered in part by a deltidium. At the point of the beak there is a very fine opening, hardly visible, which is obliterated in certain specimens. The valves are regularly bulged and have no marked sinus, so that their edge is straight. The surface is ornamented with fine, dichotomous, spiny striae; these spines, or tubes, which are 1 or 2 mm. long on the ventral valve, are hardly seen on the other valve. At 10 mm. from the beak, where the striae subdivide by dichotomy, six of them are counted in a space of 5 mm. Dimensions: Length, 18 mm.; breadth, 24 mm.; thickness, 8 mm. Relations and differences: This species belongs to the Orthis group, united by one of us under the name of Redo stnai* B and which Davidson includes in the genus Orthisina of d'Orbigny.c The two characteristics of this group consist in the direction of the strife, which, starting from the beak, never curve backward to reach the hinge crest, and in the presence of a deltidium which covers the triangular cleft of the area. The hole with which this deltidium is sometimes pierced, a characteristic on which d'Orbigny established the genus Orthisina, is of altogether secondary importance, for it appears to be only temporary. We have demonstrated that in certain LeptEense, which have an opening analogous to that of the species under discussion, that characteristic produces no significant change in the internal apparatus. (^ In having its striae provided with tubes or spines this species is distinguished from all others, except 0. striatula, with which it is impossible, on other accounts, to confound it. It may be compared either to 0. romingeri Barrande, from the primordial zone of Bohemia, which is distinguished by a rather pronounced sinus on the small valve, a more prominent beak and smooth striae; or with 0. inflexa Pander, from the lower Silurian strata of St. Petersburg, which is thicker, as observed especially in the dorsal valve, which in this respect is almost equal to the opposite valve. Moreover the striae of the Russian species are never spinous. Mr. Salter, whose kindness is never appealed to in vain, thought he recognized in our specimens a species found recently in the Lingula beds, to which, in the collection of the museum of practical geology at London, he gave the name 0. vaticina, under which we publish it. Ohservations. — In appearance this shell is closely related to Lower Ordovician species of Clitamhonites that have a fimbriated surface. If, as the authors state, many of the shells are imperforate, then it is probable that the species is closely related to and belongs with Nisusia, although the illustration of the spines indicates that they were of a different character from those of Nisusia festinata (Billings). In the presence of the statement that the shells are associated with the Primordial fossils {Paradoxides, etc.) and the absence of an opportunity to a See the note accompanying the first reference in the synonymy of Eoorthis tlyone, p. 789, and the note following text figures 70A-C, p. 789. !> Murchison, de Verneuil, et de Keyserling, G6ologie de la Russie d'Europe et de I'Oural, vol. 2, 1845, p. 179. Bull. Soc. gSol. France, 2d ser., vol. 2, 1845, p. 481. c Davidson, Introduction h I'histoire naturelle des brachiopodes, French translation by Deslongchamps, p. 130. ^^ M *' ' -^^ of sinuses and hence the provisional generic reference to ^^^^^^^ ^- f m Nothing is known with certaLaty of the outer surface ^^^^^^y T . ^^j^imi^ T or of the substance of the shell. The ulterior casts and the ^^^^o:i-''__^l - --_lJP^ L matrices of the casts show two strong radiating ridges, the A b shell substance having apparently been removed and its figuee c3.- Tr™™rfza fn^w^wiis waicott. a, b, ^^ . t ^ T u-f 'i- Narrow and hroad forms showing the two strong place lost by the compression Ol the sediment bet ore its ridges on the cast that are supposed to represent pn"n«;nlif]ation ^^® main vascular sinuses (U. S. Nat. Mus. Cat. . -^ ri T Nos. 522o5a and 52255b, respectively). The specific name is derived from Inyo County, Cah- The specimens represented are from Locality Sb, fornia. Lower Cambrian, Inyo Coanty, California. Figure e3A is copied from Waloott [I908d, PI. X, fig. 4]. Formation and locality. — Lower Cambrian : (8b) Limestones in it represents the type specimen. Tollgate Canyon, about 15 miles (24.2 km.) east of White Pine, White Mountain Range, Inyo County, California. WiMANELLA SAFFORDI (Walcott) . Plate LXXXVII, figures 7, 7a. BilUngsella saffordi Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 244. (Described and discussed as below as a new species.") General outHne of ventral valve subsemicircular and of dorsal valve transversely broad oval; greatest width of valves at about the center; hinge hne straight and a little shorter than the greatest width of the shell. A typical ventral valve has a length of 9 mm., width 9 mm. Dorsal valve, length 10 mm., width 12 mm. Biconvex, the ventral valve being more elevated at the umbo than the dorsal. Surface, so far as known, smooth or marked by concentric strise and lines of growth. Ventral valve with umbo curvmg over and terminatmg in the small apex that incurves a little over the area; area about one-half the elevation of the valve; abroad delthyrium is partly covered by a convex deltidium; casts of the interior indicate a low, tripartite pseudospondylium and one cast shows strong main vascular sinuses extending from the lateral divisions of the pseudospondylium nearly to the front margin. Dorsal valve with low area and small pseudo- cruralium ; the casts are too imperfect to show any other details. Observations. — This species occurs in the same region as Wimanella harlanensis (Walcott) and also has a smooth shell; it differs in being of equal length and breadth and in having less strongly marked interior characters. The specific name is given in recognition of the work of Mr. J. M. Safford upon the geology of Tennessee. Formation and locality. — Middle Cambrian: (14a) Sandstone of the Rome formation, along First Creek Gap, 4 miles (6.4 km.) north-northeast of Knoxville [Keith, 1905, area! geology sheet], Knox County, Tennessee. "Wimanella shelbyensis "Walcott. Plate II, figures 9, 9a. Wimanella shelbyensis Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, p. 100, PI. X, fig. 3. (Described and discussed as below as a new species. Fig. 3 is copied in this monograph, PI. II, fig. 9.) All the specimens representing this species in the collection are flattened m the shale to such an extent that very little of the original convexity of the shell is retained, and only the impression of the shell remains, as the shell substance has been entirely removed, probably by solution. The general form of this species resembles very closely that of BilUngsella fappalacTiid. 748 CAMBRIAN BRACHIOPODA. The casts show a strong cardinal area on the ventral valve, with a broad delthyrium, but not a pseudodelticlium; the dorsal valve has a narrow cardinal area with a broad open delthyrium. The exterior surface is marked by fine concentric lines and a few stronger varices of growth. A small ventral valve has a length of S mm., with a width of 10 mm. A larger one has a length of 18 mm.; ^™lth, 22 mm. A small dorsal valve has a length of 10 mm.; width, 13 mm.; and the largest dorsal valve in the collection has a length of 19 mm.; width, 25 mm. None of the specimens show any traces of vascular or muscular markings; in this respect resembling WimaneUa ? anomala (Walcott) (PL LXXXVII) and BiUingseUa ? appalacJiia Walcott (PI. LXXXVII). This species appears to be the Lower Cambrian representative of TF. ? anomala of the Middle Cambrian, differing from the latter in having rounded cardinal angles instead of the acute projecting angles so characteristic of W. ? anomala. BiUingseUa ? appalacJiia has the same general form as W. shelhjensis, but the latter differs from it in havmg a smooth surface and m the absence of all traces of radiating ribs. It more nearly resembles WimaneUa simplex Walcott (PL LXXXIX, fig. 2). It differs •from the latter m being more transverse, and the cast of the umbonal cavity is relatively smaller. It is a curious fact that in aU the species of WimaneUa mentioned there is no trace of a vascular marking or muscle scar. All the species occur in argUlaceous shale, and none of them preserve the shell substance. The shells appear to have been macerated and removed by solution, leaving only a cast of the compressed inner or outer surface of the valve. The specific name is derived from Shelby County, Alabama. Formation and locality. — Lower Cambrian: (17b) Shale in Rome {" Montevallo") formation, 4 miles {6.4 Tcm.) south of Helena: and (56c) shale in Rome ("Montevallo") formation along road just north of Buck Creek, 1.125 mile^ (1.8 km.) northeast of Helena; both in Shelby County, Alabama. WiMANELLA SIMPLEX Walcott. Text figm-e 64; Plate LXXXIX, figures 2, 2a-e. WimaneUa simplex Walcott, 1908f, Smithsonian Misc. Coll., vol. 53, No. 3, p. 101, PI. X, fig. 2. (Discussed as below as a new species. Fig. 2 is copied in this monograph, PI. LXXXIX, fig. 2.) The general form of this species is much like that of BiUingseUa coZora(?oe7isis, except that the beak of the ventral valve rises above the hinge line, much as ini?. highlandensis (PL LXXXVII, figs. 4, 4a). The surface of TF. simplex appears to be smooth except for a few concentric lines of growth. Nothing is known of the interior ,# \ except what is shown by the cast of the umbonal cavity. A crushed W' 'j| specimen vfiih the two valves flattened out (fig. 2e) indicates that the Jt beak of the dorsal valve was slightly elevated above the hinge line; it '"v.^ ,.' I is probable that figure 2 represents a dorsal valve. All the specimens ,„..„., are flattened ui shale, and the shell substance has been removed by solu- Walcott. Interior of a com- tion. The material is unsatisfactory, but as it represents a species of pressed dorsal vaiw. Foimd ^^^ smooth type from a known horizon m the Middle Cambrian, it is in Locality 35c, m a drift '^ . . block of Lower Cambrian illustrated and given a specific name. ^ shale on Mount Bosworth, British Columbia (U.S. Nat. FORMATION AND LOCALITY. — Lower Cambrian: (4v) About £00 feet (61 m.) above the Mus. Cat. No. .51407). unconform.able base of the Cam,brian and 75 feet {22.9 to.) above the top of the quartzitic sand- stones in a shale ivhich corresponds in stratigraphic position to shale No. 6 of the Dearborn River section [Walcott, 190Sf, p. 202], Gordon Creek, 6 miles {9.6 km.) from South Fork of Flathead River; and (4q and 4w) about 315 feet (96 m.) above the unconformable base of the Cambrian and 190 feet (57.9 m.) above the top of the quartzitic sandstones in a shale which corresponds in stratigraphic position to shale No. 6 of the Dearborn River section [Walcott, 1908f, p. 202], on Youngs Creek, about 5 miles (8 km.) from its junction with Danaher Creek; both in the Ovando quadrangle (U. S. Geol. Survey), Powell County, Montana. (35c) Drift blocks of siliceous shale supposed to have come from the Mount Whyte formation [Walcott, 1908f, p. 214], found-on the south slope of Mount Bosworth, a short distance northwest of the Canadian Pacific Railway track between Stephen and Hector, eastern British Columbia, Canada. BILLINGSELLID^. 749 Genus BILLINGSELLA Hall and Clarke.a Billingsella Hall and Clarke, 1892, Eleventh Ann. Rept. State Geologist New York for 1891, p. 273. (Described.) BiUingsella Hall and Clarke, 1892, Forty-fifth Ann. Rept. New York State Museum for 1891, p. 589. (Copy of preceding reference.) Kutorgina Hall and Clarke [not Walcott], 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, pp. 90-94. (Copies Walcott's description, 1886b, pp. 101-102, and discusses genus, but description and discussion also include refer- ence to specimens now referred to Billingsella, Protorthis, Micromitra, ificromitra (Paterina), and Micromitra (Tphidella).) Billingsella Hall and Clarke (in part), 1892, idem, pp. 230-231. (Described and discussed as a new genus. The genus as described also included species now referred to Nisusia.) Billingsella Hall and Clarke, Schuchert (in part), 1897, Bull. U. S. Geol. Survey No. 87, p. 158. (Characterized and discussed. The genus Protorthis is placed as a synonym of Billingsella, and among the species referred to the latter genus are species belonging with both Protorthis and Nisusia.) Billingsella Hall and Clarke, Walcott (in part), 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 227-229. (Described and ' discussed essentially as below. Species that are now referred to Wimanella were included in the genus.) Billingsella Hall and Clarke, Grabau and Shimer, 1907, North American Index Fossils, vol. 1, p. 210. (Described.) Billingsella Hall and Clarke, Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 4, PL XI, and pp. 142 and 148. (Classification of genus.) Shell subquadrate or subsemicircular in outline. Contour unequally biconvex or plano- convex. Shell impunctate. Surface striate or plicate. Ventral valve with the greatest con- vexity; carditial area moderately high, slightly mclined outward; delthyrium covered by a convex plate which ua the type species B. coloradoensis has a niinute perforation near the apex; teeth well developed, with dental plates extending to the bottom of the umbonal cavity and forming the sides of a small area opposite the delthyrium, where the pedicle muscle was probably attached. In the dorsal valve the cardinal area is strongly inclined, but less than 90° to the plane of the valve. The delthyrium is partly covered by a convex chilidium, or it may be altogether absent. Cardinal process single. A rudimentary spondylium is indicated for B. dice. Shell structure dense, minutely granular, with mmute pores scattered through the calcareous lamellae. Type. — Orthis coloradoensis Shumard. Ohservations. — Hall and Clarke [1892c, p. 2.30] founded the genus on "Orthis pepina" Hall, wliich is a synonym of "Orthis coloradoensis" Shumard. The material from the limestones of Texas in the United States National Museum shows the form of the teeth in the ventral valve, also the deltidium and the minute perforation near its apex. Hall and Clarke [1892c, p. 230] state in their diagnosis that "in rare instances (it) may be minutely perforated atthe apex," but do not name the species in which the perforation occurs or where the specimens showing it are to be found. All the species known to me are biconvex or plano-convex; none are concavo- convex as defined by Plall and Clarke [1892c, p. 230]. The genus is essentially orthoid, but it differs in the presence of the arched deltidium and its general aspect from typical examples of the Orthidfe, and its shell is of a dense, nonfibrous structure. a The synonymy for this genus does not give a complete record of the various genera under which the species now included in Billingsella were formerly placed; it gives only those references in which the genus is discussed or described. To complete the record the following mere generic references are listed: Orthis Barrande [1848, p. 203]. Orthis Shumard [1860, p. 627]. Orthis Hall [1863, p. 134; 1867, p. 113]. Orthis Davidson [1868, p. 314; 1869, p. 230], Orthis Linnarsson [1876, pp. 10, 12, and 13]. Orthis Barrande [1879b, Pi. LXII, Qg. 11]. Orthis Whitfield [1882, p. 170]. Orthis? (Orthisina?) Hall [1883, PI. XXXVII, figs. 16-19]. Orthis Kayser [1883, p. 35]. Kutorgina Walcott [1884b, p. 18]. Orthisina Whitfield [ 1884, p. 144]. Orthis? Walcott [lS86b, p. 119]. Orthisina. Walcott [1886b, p. 120]. Orthis Walcott [1887, p. 190]. Orthis Oehlert [1889, p. 1139]. Orthis? Walcott [1891a, p. 612]. Orthisina Walcott [1891a, p. 613]. Clitambonites (Gonambonites) Matthew [1895b, p. 267]. Orthis Wallerius [1895, p. 66]. Orthis Pompeckj [1896b, p. 513]. Orthis (Billingsella) Sardeson [1896, p. 96]. Clilamhonitcs Schuchert [1897, p. 184]. ■Billingsella Walcott [1899, p. 450]. Billingsella Matthew [1903, p. 148]. Orthis (.Plectorthis) Walcott [1905a, p. 270]. Billingsella Walcott [1908d, pp. 101 and 102]. 750 CAMBRIAN BRACHIOPODA. Of the species referred to the genus, Billingsella exporrecta is one tliat departs from the t3-pical species in tlie absence of a strong convex deltidium, and B. dice has a rudimentary spondylium m the ventral valve, a character not developed in other species of the genus. For the relations of Billingsella to Nisusia, see remarks under the latter genus, page 725. The genus was named in honor of Mr. E. Billings. Billingsella? appalachia Walcott. Plate LXXXVII, figures 2, 2a-b. Billingsella f appalachia Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 231. (Described as below as a new species.) The outhne of the dorsal valve is rounded subquadrate. The height and width of the ventral valve are about the same. Dorsal valve slightly transverse. The surface is marked by round, very fine, radiating costse, and lines of growth, with very fine interstitial concentric striae. The average ventral valve is about 10 mm. in height, with an equal width. The largest shell observed was a ventral valve with a width of 14 mm. Cardinal area of the ventral valve rather low. It is divided midway by a rather strong delthyrium. Observations. — In form and size this shell is much like that of Wimanella? anomala. It differs m its strongly marked surface characters. All the specimens are flattened in the shale and nothing is known of the interior characters. Formation and locality. — Middle Cambrian: (121) Rogersville shale, road just east of Harlan Knob, 4 miles (6.4 km.) northeast of Rogersville [Kiith, 1905, areal geology sheet], Hawkins County, Tennessee. This species is somewhat doubtfully identified from the foUowing locality: Middle Cambrian: (14) Limestones overlying the sandstones of the Rome formation, near the wagon road and in a quarry near the railroad track, 7 miles (11.2 km.) southwest of Rome [Hayes, 1902, historical geology sheet], Floyd County, Georgia. Billingsella bivia n. sp. Text figures 65A-C. The specimens of this species are preserved in a sandstone and usually occur in the form of flattened casts. The valves are transverse in outline, equally convex, and have their great- est width at the liinge line. The beak of the ventral valve projects over the hinge line and Figure 65. — BiUingsellaUvia n. sp. A, A', Top and side view of exfoliated dorsal valve, the type specimen, from Locality 141, Lower Cambrian ^ near Resting Springs, Inyo County, California (U.S. Nat. Mus. Cat. No. 52254a). B, Enlargement (Xabout 6) of the outer surface, withstrong and fine radiating ribs, of ashell from Locality 14p, Lower Cambrian, near Resting Springs, Inyo County, California (U. S. Nat. Mus. Cat. No. 51404), C, Ventral valve from Locality 141, Lower Cambrian, near Resting Springs, Inyo County, California (U. S. Nat. Mus. Cat. No. 52254b). is flattened so that it. barely rises above the plane of the margins of the shell. The hinge line of the dorsal valve is broadly rounded, and most of the specimens show a fairly well marked mesial sinus. A dorsal valve preserving the outer surface shows it to have been covered by coarse, radiating costse, each of which is marked by a number of minute radiating ridges. The species is closely related to Billingsella TiigJilandensis (Walcott), but differs from that species in being more transverse in outline, in the absence of a concentric striation, and in other details of surface sculpture, and in the prominence of the mesial sinus. Formation and locality. — Lower Cambrian: (141) Sandstones about 2,800 feet [853 m.) below the Middle Cambrian in a horizon correlated with No. 2j of the Silver Peak group of the Waucoba Springs section [Walcott, 190Sf, p. BILLINGSELLIDiE. 751 187], in the pass about 7 miles {11.2 km.) east of Resting {Freshwater) Springs; and (14?) sandstones near Resting (Fresh- water) Springs; both in the southwest corner of T. 21 N., R. 8 E., on Amargosa River, in the southeastern part of Inyo County, California. BiLLINGSELLA COLORADOENSIS (Shumarcl). Text figures 6, page 299, 66; Plate LXXXV, figures 1, la-z. Orthis coloradoensis Shumard, 1860, Trans. Acad. Sci. St. Louis, vol. 1, p. 627. (Described as a new species.) Orthis pepina Hall, 1863, Sixteenth Ann. Rept. New York State Cab. Nat. Hist., pp. 134-135, PI. VI, figs. 23-27. (Described and discussed as a new species.) Orthis pepina Hall, 1867, Trans. Albany Inst., vol. 5, p. 113, PI. I, figs. 23-27. (Copy of preceding reference.) Orthis pepina Hall, Whitfield, 1882, Geology of Wisconsin, vol. 4, pt. 3, pp. 170-171, PL I, figs. 4 and 5. (Described and discussed.) Orthis? {Orthisina?) pepina Hall, 1883, Second Ann. Rept. State Geologist New York for 1882, PL XXXVII, figs. 16-19. (Figs. 16-19 are copied from Hall, 1863, PL VI, figs. 23, 25, 24, and 26, respectively.) Billingsella pepina (Hall), Hall and Clarke, 1892, Eleventh Ann. Rept. State Geologist New York for 1891, PL VIII, figs. 1 and 2. (No text reference.) Billingsella pepina (Hall), Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, p. 230, PL VII,. figs. 16-19; PL VIIA, figs. 7-9. (Mentioned in description of genus. PI. VII, figs. 16-19, are copied from Hall, 1863, PL VI, figs. 23, 25, 24, and 26, respectively. Figs. 8 and 9 are copied fi-om figs. 1 and 2, respec- tively, of the preceding reference.) Orthis {Billingsella) pepina (Hall), Sardeson, 1896, Bull. Minnesota Acad. Nat. Sci., vol. 4, No. 1, pt. 1, p. 96. (New localities mentioned.) Billingsella coloradoensis (Shumard), Schuchert, 1897, Bull. U. S. Geol. Survey No. 87, p. 158. (Merely changes generic reference.) Billingsella coloradoensis (Shumard), Walcott, 1899, Mon. U. S. Geol. Survey, vol. 32, pt. 2, pp. 450-451, PL LXI, figs. 1, la-d. (Discussed and characterized. Figs. 1, la-d are copied in this monograph, PL LXXXV, figs, la, Ig, Iw, lo, and It, respectively, figs. Iw and It being slightly altered.) Billingsella coloradoensis (Shumard), Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 231-234. (Described and discussed essentially as below.) Billingsella coloradoensis (Shumard), Grabau and Shimer, 1907, North American Index Fossils, vol. 1, p. 210. (Char- acterized.) Shell usually transverse but in many examples the ventral valve is longer than wide. The general outhne is irregularly subquadrate to subsemicircular. On the ventral valve the hinge line slopes toward the beak at a low angle while in the dorsal valve it is nearlj^ straight. In some individuals the greatest width is at the hinge line. In others it is at about the middle. There is considerable variation in the relative proportions of length and breadth. The ventral valve is slightly more convex than the dorsal. The degree of convexity of the two valves varies ... . ,.„ , ,. . r, p Figure 6R.— Billingsella coloradoemis (Shumard). considerably m specimens from ditterent locahties. borne or posterior view of a ventral vaive showing the ventral valves from beds at Franconia, Minnesota, and pedicle opening in the deiodium; from Locai- .,,„_- , .^TT-. . j_ 1 ity '", Upper Cambrian, on Morgans Creek, ■ the young sheUs from Trempealeau, W isconsm, are strongly Texas (u. s. Nat. mus. cat. No. 34777a). convex. A low, broad, median sinus occurs on nearly all specimens of the dorsal valve, being straight in the young shells, and occasionally a shallow sinus is clearly defined on the ventral valve. It is quite rare to find a well-marked median fold on the ventral valve. The surface is marked by sharply rounded, radiating costse crossed by fine concentric lines of growth and very fine, slightly undulating, concentric striae. The size and sharpness of the radiating ribs vary greatly in specimens from the same bed at the typical locality in Texas. Shells occur with strong rounded costse, and no traces of fine elevated lines between, whereas others show from one to four or more lines that start at varying distances from the beak. The irnbricating lines of growth give a concentrically ridged aspect to some shells, though others are nearly smooth from beak to frontal margin. The increase in the number of ribs is by interpolation, not by bifurcation. There is considerable variation in the size of the shell. The largest specimens from Texas have a transverse diameter of 19 mm., with a length of 14 mm. for the dorsal valve, and about 18 mm. for the ventral valve. Specimens of the ventral valve from the Yellowstone National Park have a length of 14 mm. with a width of 15 mm. 752 CAMBRIAN BEACHIOPODA. Cardinal area of ventral valve moderately liigh. It is marked by transverse striae of growth tliat cross it parallel to its base and arch over the convex deltidium. The plane of the area extends backward at an angle of about 10° to the plane of the margin of the shell. The delthyrium is strong and covered by a convex deltidium, the front margin of which arches back about one-fifth the length of the delthyrium. The deltidium is marked by concentric "strise of growth and fine radiating lines and a minute perforation near its apex. The cardinal area of the dorsal valve is short as compared with the ventral valve. It extends backward at an angle of about 45° to the plane of the margin of the valve. It is divided midway by a strong delthyrium which is covered for about half its distance by a convex chilidium. In the interior of the ventral valve the hinge teeth appear to be supported by dental plates that extend down to the bottom of the valve and bound the tripartite umbonal space opposite the delthyrium into which the vascular sinuses extend on each side of the diductor muscle impressions, or their path of advance. The traces of the vascular system are confined to the main vascular trunks which extend forward nearly to the front margin, where in some examples they are bifurcated. The inner branch extends in toward the median line, disap- pearing in the numerous radiating depressions near the margin. The lateral branches appear to connect with the peripheral canal that arches about the space probably occupied by the ovarian areas, between itself and the main vascular trunks. The space for the attachment of the muscles between the main vascular trunks appears to have been quite large, extending for- ward to the anterior fifth of the length of the valve, but no subdivisions indicating the points of attachment of the different muscles have been detected. The pedicle muscles were probably attached to the elevated, posterior portion of this central area. In some casts this posterior area is scarcely elevated above the plane of the interior. In others it is fairly prominent. In the interior of the dorsal valve the interior of the deltidial cavity supports a small well- developed cardinal process or callosity, and a slight narrow median ridge occurs just in advance of the deltidial cavity. The crura are short and well defined, with relativelj^ shallow dental sockets beside them. The cardinal process and crura vary in size and length in shells from the sanie locality. The only traces of the muscle scars observed show the anterior adductor impressions. The vascular trunks of the dorsal valve diverge from the central line about the center of the shell, after passing around the adductor muscle impressions. Observations. — The average size of the typical specimens from Texas is from 10 to 14 mm. in length for the ventral valve, the width being about the same. At one locality on Morgans Creek several dorsal valves were found that have a width of 18 mm., with a length of 12 mm. This may possibly indicate a variety or distinct species, but with the material in the collec- tion it is impossible to determine definitely. The shells from the upper Mississippi Valley in Wisconsin and Minnesota average about the same size as the typical forms from Texas. The young shells are much more convex. The material from the Gallatin Range, Yellowstone National Park, is also much like that from Texas, but that from the limestone near Malade, Idaho, though it contains typical shells, also has specimens as large as those from Morgans Creek, Texas. BiUingsella major differs from B. coloradoensis in the character of the surface striation, also in its larger size. BiUingsella plicatella is a uniformly smaller and more convex shell, and also has distinct surface characters. The same is true of B. striata. Formation and locality. — Lower Ordovician: (339 [Sardeson, 1896, pp. 95 and 96]) Oneota dolomite, Still- water, Washington County, Minnesota. TTpper Cambrian : (302q) About 1,000 feet (305 m.) above the quartzitic sandstones in the ' ' Yogo limestone (Devono- Silurian)" of W. H. Emmons [1907, p 34], on Rock Creek, Phillipsburg quadrangle (U. S. Geol. Survey), Granite County; (302r) same horizon as Locality 302q, near Princeton, Phillipsburg quadrangle (U. S. Geol. Survey), Granite County; (302f) limestone in upper part of the Gallatin formation, north side of Elk Pass, between Buffalo and Slough Creeks, Yellowstone National Park, Livingston quadrangle (U. S. Geol. Survey); (147a) limestone in Spring Hill Canyon, west side of the Bridger Range, Gallatin County; and (155) limestone north of East Gallatin River, near Hillsdale, Threeforks quadrangle (U. S. Geol. Survey), Gallatin County; all in Montana. (302p) Middle limestone of the Deadwood formation near the summit of the Owl Creek Mountains, 18 miles (29 km.) southwest of Thermopolis, Fremont County; (302g) limestone on the north slope of Crowfoot Ridge south of the BILLINGSELLID^. 753 Gallatin Valley, Gallatin quadrangle (U. S. Geol. Survey), Yellowstone National Park; and (3021i) limestone on the divide between Panther Creek and West Gallatin (Gallatin) River, Gallatin quadrangle (U. S. Geol. Survey), Yel- lowstone National Park; all in Wyoming. (4y, 6a, 5c, and 54t) Limestones about 250 feet (76 m.) above the Middle Cambrian; (54x) limestone about 200 feet (61 m.) above the Middle Cambrian; and (54u) limestone about 100 feet (30.5 m.) above the Middle Cambrian- all in the St. Charles formation [Walcott, 1908a, p. 6], on the north side of Twomile Canyon, near its mouth, 2 miles (3.2 km.) southeast of Malade, Oneida County, Idaho. (56g) Limestones of the St. Charles formation [Walcott, 1908a, p. 6], in the valley of the stream which flows into Mill Canyon from the west, about 6 miles (9.6 km.) west-southwest of Liberty, and 15 miles (24.2 km.) west of Montpelier, Bear Lake County, Idaho. (54e) About 200 feet (61 m.) above the Middle Cambrian and 1,025 feet (312.4 m.) below the top of the Upper Cambrian, in limestones forming 3 of the St. Charles formation [Walcott, 1908f, p. 193]; (31m and 551i) about 175 feet (53.3 m.) above the Middle Cambrian and 1,050 feet (320 m.) below the top of the Upper Cambrian, near the base of the limestones forming 3 of the St. Charles formation [Walcott, IQOSf, p. 192]; and (54f) 150 feet (45.7 m.) above the Middle Cambrian and 1,075 feet (327.7 m.) below the top of the Upper Cambrian in the light-gray sandstone formino- 4 of the St. Charles formation [Walcott, 1908f, p. 193]; all in Blacksmith Fork Canyon, about 10 miles (16.1 km.) east of Hyrum, Cache County, Utah. (14b) Limestone on Cold Creek at north end of gorge opposite the north end of Sponge Mountain, 2 miles (3.2 km.) south of the San Saba County line, in Llano County; (14g) limestone 1 mile (1.6 km.) west of Cherokee San Saba County; (68 and 68e) interbedded sandstone and limestone, Packsaddle Mountain, Llano County; (69) lime- stone near Honey Creek, Burnet County; (70, 70a, and 70e) limestones near Morgans Creek, Burnet County; (363a [Shumard, 1860, p. 627]) sandstones near the head of Morganis Creek, Burnet County; and (71) limestone in Cold Creek Canyon, Burnet County; all in Texas. (369e) Sandstone on Big River, Iron County; (369d) upper portion of the Elvins formation, 2.5 to 3 miles (4 to 4.8 km.) north of Caledonia, Washington County; (11 1) arenaceous limestone of the Elvins formation, 50 feet (15.2 m.) above the "Edgewise beds," St. Francois County; and (lid) arenaceous limestone about 2 miles (3.2 km.) north of Montana, in sec. 22, T. 35 N., R. 1 E., Iron County; all in Missouri. "St. Croix sandstone" at the following localities: (78) Quarry near St. Croix River in suburbs of Osceola, Polk County; (79) bluff near Hudson, St. Croix County; (79a) quarry and ledge 0.5 mile (0.8 km.) southeast of the county courthouse, Menomonie, Dunn County; (100) near Menomonie, Dunn County; (80a) 4 miles (6.4 km.) north of Reedsburg, Sauk County; (83') uppermost horizon near Trempealeau, Trempealeau County; (97a) near Winfield Jefferson County; (338c) at Alma, Buffalo County; and (328d [WTiitfield, 1882, p. 171]) at Berlin, Green Lake County; all in Wisconsin. (83') Green-sand horizon in the "St. Croix sandstone" below the "fifth trilobite bed" of Owen, at Trempealeau Trempealeau County, Wisconsin. "St. Croix sandstone " at the following localities: (84a) River Junction, Houston County, 20 miles (32.2 km.) below Dresbach; (97b) below the green-sand bed and about 25 feet above St. Croix River, at Franconia, Chisago County (86a) near Red Wing, Goodhue County; (97 and S97x) at Reads Landing, foot of Lake Pepin, Wabasha County; (131) in a cut on the Chicago, Milwaukee and St. Paul Railway, 4 miles (6.4 km.) southeast of Lake City, Wabasha County; (339f) near Minneiska (Miniska), on Mississippi River near the line between Wabasha and Winona counties; (339h [Hall, 1863, p. 135]) near the mouth of Minneiska (Miniska) River, near the line between Wabasha and Winona counties; (98a) at Marine Mills, on St. Croix River, Washington County; and (339g) just below the Dicellocephalus minnesotensis beds, near Winona, Winona County; all in Minnesota. Upper? Cambrian: (306) Sandy limestone on Gravel River, on the eastern slope of the Rocky Mountains, in the Mackenzie Basin, British Columbia. Middle Cambrian: (5k) Limestone in Meagher County on the road to Wolsey, about 1 mile (1.6 km.) south of the divide at the head of Sawmill Creek, and 8 miles (12.8 km.) south of Neihart, Little Belt Mountains quadrangle (U. S. Geol. Survey), Cascade County; (302w) limestone at Madison Mountain; and (159) limestones north of West Gallatin (Gallatin) River, Gallatin County; all in Montana. (4e) Limestones about 950 feet (289.6 m.) above the unconformable base of the Cambrian in the divide at the head of Jackson Creek (locally known as Sheep Creek), a creek flowing into Jackson Lake about 0.5 mile (0.8 km.) south of its northwestern corner, Teton Mountains, Grand Teton quadrangle (U. S. Geol. Siu-vey), Uinta County, Wyoming. (5b and 64s) Dark blue-gray Langston limestone [Walcott, 1908f, p. 198], just above the Cambrian quartzitic sandstones, north side of Twomile Canyon, near its mouth, 2 miles (3.2 km.) southeast of Malade, Oneida County, Idaho. (54o) About 900 feet (274.3 m.) above the Brigham quartzite and 3,300 feet (1,005.8 m.) below the Upper Cam- , brian, in the limestone forming lb of the Ute limestone [Walcott, 1908f, p. 196], in Blacksmith Fork Canyon, about 10 miles (16.1 km.) east of Hyrum, Cache County, Utah. (lie) Thin-bedded limestones south-southwest of Potosi, Washington County, Missouri. (2s) Limestone in upper part of Paradoxides zone, Hastings Cove [Matthew, 1898b, p. 38], on Kennebecasis Bay, 0.5 mile (0.8 km.) northeast of Torryburn on the Intercolonial Railway northeast of St. John, St. John County, New Brunswick. , 62667°— VOL 51. pt 1—12 48 754 CAMBRIAN BRACHIOPODA. BiLLINGSELLA DICE Walcott. Plate CI, figures 8, 8a-d. ; dice Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 234. (Characterized essentially as below as a new species.) In general form and surface this shell is related to B. romingeri (Barrande). It differs from the latter in its strong dental plates, which form a rudimentary spondylium. All the characters known are illustrated. Formation and locality. — lower Ordovician? : (319f) Drift bowlder of sandstone found near St. Albans, Franklin County, Vermont. The lithologic character of the matrix in which this species was found points to the arenaceous limestones of the Phillipsburg formation just north of the boundary between the United States and Canada as the source of the bowlder. BiLLINGSELLA EXPORKECTA (Linnarssou). Plate LXXXVIII, figures 1, la-1. Orthis exporrecta Linnarsson, 1876, Bihang till K. svensk. Vet.-Akad. Handl., Bd. 3, No. 12, pp. 12-13, PI. II, figs. 13-19; PI. Ill, figs. 20 and 21. (Described and discussed in English as a new species.) Orthis expoirecta Linnarsson, Kayser, 1883, China, by Richthofen, vol. 4, p. 35. (Discussed in German in the descrip- tion of "0. linnarssoni.") Orthis exporrecta Linnarsson, Walleriu.s, 1895, Undersokningar ofver Zonen med Agnostus Ixvigatus i Vestergotland, p. 66. (Localities mentioned in Swedish.) Billingsella exporrecta (Linnarsson), Walcott, 1905, Proc. IT. S. Nat. Mus., vol. 28, pp. 234-236. (Described and discussed essentially as below.) Shell transversely subsemicircular, with the liinge line usually shorter than the greatest width. In a few examples it is a trifle longer; the cardinal angles are obtusely angular (PI. LXXXVIII, fig. le). The proportions between the length and breadth vary, as shown by the figures. The ventral valve is considerably more convex than the dorsal. The ventral valve is evenly rounded, while the dorsal usually has a flattening of the median area and some- times a slight, broad sinus. The surface is marked by numerous radiating costse and very fine concentric striae between the costse, and a few visible lines of growth. The costse are rounded, usually, but not always, broader than the interspaces, and continuous from the umbo to the front and lateral margins; they appear to be quite regular, although varying much in size, and increasing somewhat irregularly by interpolation of new costse. Tlris usually occurs near the umbo, but may occur near the middle of the valve. The largest ventral valve in the collection has a length of 9 mm. and a breadth of 11 mm. Dorsal valve: Length, 7 mm. ; breadth, 10 mm. Cardinal area of ventral valve high and overhanging the posterior margin. Delthvrium large and triangular in outline; deltidium short, concave, imperforate, and marked by fine, transverse strije of growth. Cardinal area of dorsal valve short and inchned slightly forward; it is divided midway bj^ a broad delthyrium, which is divided by a strong cardinal process. In the interior of the ventral valve strong main vascular sinuses extend well forward toward the front margin. The cast of the umbonal cavity opposite the delthyrium shows a tripartite division, the center of wliich is the area of the path of advance of the diductor muscle impressions, and those on each side appear to be the posterior portion of the main vascular sinuses. The anterior edge of the cavity is marked by a sharp, elevated, forward- arching ridge that extends to the teeth on either side; the dental plates appear to have extended to the bottom of the valve and to have bounded the sides of the triangular umbonal cavity opposite the delthyrium. The interiors of the dorsal valve are beautifully preserved. The cardinal process, crura, crural plates, area, anterior and posterior adductor muscle scars, and vascular sinuses are very distinct; the dental sockets are shallow, but clearly shown. The great variation in the size, form, and position of the adductor scars is well illustrated by the figures. In figure If there appear to be two lateral supporting septa to the thickening before the crural plates that BILLINGSELLID^. 755 bound the spaces occupied by the point of attachment of the diductor muscles. Linnarsson describes [1876, p. 12] the cardinal process as triangular. I find it both straight (fig. If), subtiiangular (fig. li), and triangular (figs. Ig and Ih). A short median septum is seen in some shells (fig. Ig), but usually the strong, sHghtlj^ rounded, flattened median ridge does not carry it. Observations. — This is one of the most variable species of the genus, both in external, and, as far as loiown, internal characters. It is very abundant, but interiors of the ventral valve are rarely met with in good condition. The extremely short, imperforate deltidium of the ventral valve indicates that the pedicle opening had been closed by shell growth, and that this species was nearing the Eoorthis rem- nicha stage of development. It appears to be an intermediate form between Billingsella and Eoorthis. The concave deltidium is much like that of Conchidium nysius Hall and Whitfield [Hall and Clarke, 1894, PI. LXIV, fig. 7]. It is about one-fifth the length of the delthyrium. Linnarsson [1876, p. 12] compares "Orthis exporrecta" with "Orthis Mcksi," which appeared to Tje most nearly related, pointing out that it differed in ha\'ing fewer and coarser ribs, less pointed beak, and lower area. The "Orthis hicJcsi" variety is now placed as a variety of Billingsella exporrecta. Formation and locality. — Upper? Cambrian: (3101i) Shale collected somewhere (probably Fogelsang) in the old province of Skane, Sweden. Middle Cambrian: Limestones of the Paradoxides forchhammeri zone at the following localities: (380m) " at Kinnekulle, northeast of Lidkoping, Province of Skaraborg; (320n) at Lovened, Djupadal, 19 miles (30.6 km.) south-southeast of Skara, Province of Skaraborg; (320y)a at Gudhem, 12.5 miles (20,1 km.) south-southeast of Skara, Province of Skaraborg; (320p)'' at Sodra Mockleby, southern part of Oeland Island; (320z)a several places in Nerike; (320g) at Borgholm, Oeland Island; (321q) at Munkesten, north of Hunneberg; and (321r) at Hunneberg, western boundary of the Province of Skaraborg; all in Sweden. (320 l)^JT width about midway of the length; mesial furrow j^Mpf narrow at the beak and gradually widening to a -..<™,».-— ^«^^k: — J. bpoad, deep furrow, which divides the valve into two lobes. Figure 67. — BiUingseUa marion V^^alcott. A, Dorsal valve, the Of +1 '+1.. +1 ^ +* f f tj'pe specimen, showing extension of the cardinal angle and OUriace SmOOtll, Wltll tne exception Ot a teW a very broad mesialtorrow. B, Dorsal valve with obscure (six Or Seveu) obsCUre radiating ribs OU Cacll lobe. , , , , ,.^ ... ,,.,j, A specimen 10 mm. in width has a length of 6 mm. The specimens represented are from Looahtj' 581, Middle r _ _ _ & Cambrian on Mount Stephen, British Columbia (u. s. Nat. Observations. — Tliis spccies is represented by Z^^t^^^^I^T^Zt"'' ""^""' three specimens of the dorsal valve. They allm- dicate a thick shell of the Billingsella salemensis (Walcott) type (PI. LXXXVII, figs. 3 and 3a). The specific name was given for Mrs, L. D, Burling, who collected the type specimen. Formation and locality. — Middle Cambrian: (581) About 1,830 feet (557.8 m.) above the Lower Cambrian in limestones forming 3b ot the Stephen formation [Walcott, 1908c, p. 238 (7)], on the east side of Mount Stephen, about 3,000 feet (914.4 m.) above the Canadian Pacific Railway track, 3.5 miles (5.6 km.) east of Field, British Columbia,. Canada. Billingsella obscuea Walcott. Plate LXXXVI, figure 6. Billingsella obscura Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 239. (Characterized as below as a new species.) This species is founded on a single dorsal valve that occurs in the form of a cast in sand- stone. It is transverse, width IS mm., length 13 mm.; moderately convex, with a slightly defined mesial flattening that broadens out nearly to three-fifths the width of the shell at the front margin. The surface of the cast is marked by a few faintly defined, rather broad costae. The shell is much like the large dorsal valves of Billingsella coloradoensis . It differs in its broader frontal margin and median flattening. Formation and locality. — Middle Cambrian: (74) Sandstone about 300 feet (91.4 m.) above the base of the Tonto group at the head of Nunkoweap Valley, Grand Canyon of the Colorado, Arizona. BILLINGSELLIDiE. 759 BiLLINGSELLA ORIENTALIS (Whitfield). Plate LXXXVI, figures 2, 2a-b. Orthisina orientalis WsiiFiEhD, 1884, Bull. Am. Mus. Nat. Hist., vol. 1, p. 144, PI. XIV, fig. 6. (Described and discussed as a new species. Fig. 6 is copied in this monograph, PI. LXXXVI, fig. 2.) ■Orthisina orientalis 'V^'hitfield, Walcott, 1886, Bull. U. S. Geol. Survey No. 30, p. 120, PI. VII, fig. 6. (Original description, Whitfield, 1884, p. 144, copied and species discussed. Fig. 6 is copied from fig. 6 of the preceding reference.) Orthisina orientalis Whitfield, Walcott, 1891, Tenth Ann. Kept. U. S. Geol. Survey, p. 613, PI. LXXII, fig. 8. (Men- tioned. Fig. 8 is copied from Whitfield, 1884, PI. XIV, fig. 6.) Billingsella orientalis (Whitfield), Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, p. 230. (Merely changes generic reference.) Billingsella orientalis (Whitfield), Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 239-240. (Described and dis- cussed as below.) The original description by Whitfield follows : Shell quadrangular in outline, somewhat higher than wide, with vertical and subparallel lateral margins, and broadly rounded base. Cardinal line rapidly sloping from the apex to the extremities, which are slightly rounded. Hinge line straight, as long as the greatest width of the shell. Cardinal area broad and high, divided in the middle by a triangular foramen, which is about as high as wide. Surface of the ventral valve moderately convex, marked by very fine radiating striae and also by several concentric lines of growth. Filling of the rostral cavity and foramen large and prominent. Specimen, a cast in shale, of the ventral valve only. Ohservations. — The type specimen as described above is flattened in the shale, and also appears to be compressed laterally. Uncompressed specimens referred to this species, from the siliceous limestones east of Swanton show the ventral valve to have been rather strongly convex, and the dorsal valve moderately so. The outer surface as shown in the cast indicates that it was somewhat like that of Billingsella Colorado ensis, but that it difl'ers in having finer and more numerous threadlike costse. A few traces of concentric striae and lines of growth are preserved. The material is very unsatisfactory, but it is sufficient to indicate that the genus occurs in association with OleneUus thompsoni in the upper beds of the Lower Cambrian section. Formation and locality. — lower Cambrian: (25a) Limestone on the Hall (Donaldson's) farm, 2 miles (3.2 km.) east of Swanton; (26) sandstone northeast of the Corman farm buildings, east of Highgate Springs; (319m) shales of No. 6 of the section at Parker's quarry [Walcott, 1891b, p. 278], near Georgia; and {319s [Whitfield, 1884, p- 144])shales at Parker's quarry, near Georgia; all in Franklin County, Vermont. Billingsella plicatella Walcott. Text figure 1, page 299; Plate LXXXVI, figures 3, 3a-n. Billingsella plicatella Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 240-241. (Described and discussed as below as a new species.) Shell irregularly subquadrate in outline. In the ventral valve the cardnial line slopes toward the beak at an angle of from 5° to 10°, whereas in the dorsal valve it is usually about 1° to 3°. The greatest width of the shell is about the middle. There is some variation in the relative proportions of length and breadth. Usually, however, the ventral valve is fully as long as wide, while in the dorsal valve it is slightly transverse. The ventral valve is rather strongly convex, the dorsal valve being less so. A low, broad mesial sinus occurs on nearly all specimens of the dorsal valve, and sometimes a distinct sinus on the ventral valve. The surface is marked by costse that give it a plicated appearance in many specimens; also, concentric lines of growth and very fine, slightly undulating striise. On some shells the costse and surface markings have been almost entirely removed by abrasion while in others they are clear and distinct. There is a considerable range of variation in the strength and form of the surface markings. These are illustrated by the figures on Plate LXXXVI. When the shell is exfoliated, fine radiating lines occur toward the front margins. The average size of the shell gives a width of about 8 mm., and in the ventral valve a nearly equal length. One specimen has a width of 11 mm. 760 CAJ^IBKIAN BRACHIOPODA. Cardinal area well defined. It is marked by transverse strise of growth parallel to the base. The plane of the area extends backward over the cardinal line at an angle of 10° to the plane of the margm of the shell. The delthyrium is well defined and covered by a convex deltidium, the extent of which, however, is unknown. The cardinal area of the dorsal valve is short. No details of the structure have been observed. The cast of the interior of the ventral valve indicates short liinge teeth supported by dental plates. The markings left on the shell by the vascular system, as shown in casts, are two main vascular trunks which extend nearly in a straight line from the side of the cast of the deltidial cavity obliquely outward to the anterior fourth of the valve, where they bifurcate. The inner branch extends in toward the median line, while the lateral branches extend out- ward, appearing to unite with the peripheral canal. The latter arches about the space that was probably occupied by the ovarian areas, between itself and the main vascular trunks. The spaces for the attachment of the muscles between the main vascular trunks appear to have been large. No subdivision indicating the points of attachment of the different muscles has been detected. At the posterior portion of the central area there was a narrow, elevated space that posteriorly passes into the deltidial cavity. The pedicle muscles were probably attached to the front part of this elevated space. Short, radiating striae near the margia indicate the presence of minute vascular canals. In the interior of the dorsal valve the interior of the deltidial cavity supports a small, well -developed cardinal process or callosity. The crura are short and small, with rounded dental sockets beside them. Nothing is definitely shown of the vascular trunks or mesial impressions in the dorsal valve. Observations. — In form this species is not unlike the convex forms that have been referred to Billingsella coloradoensis (Shumard) from Trempealeau, Wisconsin. It differs from the latter in having strongly marked surface plications and a narrower deltidium. From B. striata it differs in surface characters; also in having a more convex dorsal valve. Formation and locality. — Upper Cambrian: (150a, 153, and 154) Limestones on Dry Creek, just above tlie mouth of Pass Creek, about 5 miles (8 km.) north of Hillsdale; (151a) limestone in point overlooking Chum Canyon on the west side of the Bridger Range; (157 and 158) O' limestone north of East Gallatin River, near Hillsdale; and (156b) limestone north of East Gallatin River, at the north end of the Gallatin Valley; all in the Threeforks quadrangle (U. S. Geol. Survey), Gallatin County, Montana. (152) Limestone on ridge between Chum and Cottonwood canyons; and (151) limestone in point overlooking Chum Canyon; both on the west side of the Bridger Range, Gallatin County, Montana. Middle Cambrian: (9h) Limestone on Beaver Creek, 5 miles (8 km.) north of York, about 8 miles (12.8 km.) north of Canon Ferry, Big Belt Mountains, Fort Logan quadrangle (U. S. Geol. Survey), Meagher County, Montana. (4j) Limestone at the head of Deep Creek, Canyon quadrangle (U. S. Geol. Survey), Yellowstone National Park, Wyoming. Billingsella pumpellyi Walcott. Plate XCVII, figures 8, 8a-c. Billingsella pumpellyi Walcoti, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 242. (Described and discussed as below as a new species.) General outline subsemicircular, greatest mdth at the hinge line or a little in advance of it; considerable variation exists in the relative proportions of length and \vidth; a ventral valve 8 mm. long has a width of 9 mm.; the dorsal valve is more transverse, length 5.5 mm., width 8 mm. The ventral valve is strongly convex, with the umbo arching over to the apex, which is a little above the plane of the margins of the valve; a very slight median fold occurs near the front margin; dorsal valve slightly convex and with a shallow median sinus. The surface is marked by low, sharp ribs with wide interspaces on wliich fine radiating • strise occur. Concentric lines and strise of growth cross the radiating strise and ribs. The characters of the cardinal areas of the valves are almost unknown; that of the ventral valve appears to have been of moderate height and inclined but a little from the plane of the valve; one interior of the dorsal valve shows a low cardinal process. The cast of the interior a 168 is tlie type locality. BILLINGSELLID^. 761 of the ventral valve shows the presence of a tripartite, elevated umbonal space into which the strong main vascular sinuses extend, as in Billingsella coloradoensis (Shumard); the sinuses extend forward nearly to the front margin of the valve. Of the interior of the dorsal valve only the presence of a strong median ridge is known. Observations. — This species is one of the costate species of the type of Billingsella colorado- ensis (Shumard) and B. romingeri (Barrande). It differs from them in surface characters. It may be considered the trans-Pacific representative of B. coloradoensis. The specific name was given in honor of Raphael Pumpelly. Formation and locality. — Tipper Cambrian: (C36) Upper part of the Chaumitien limestone [Blackwelder, 1907a, p. 36 (part of 3d list of fossils), and fig. 9 (bed 2), p. 35], at Chaumitien, Changhia district; and (C61) a dense black limestone in the uppermost limestone member of the Kiulung group [Blackwelder, 1907a, pp. 37 and 41 {3d list of fossils)and fig . 10 {bed 13), p. 55], 5 mMes {4-8 km.) southwest of Yenchuang; both in Shantung, China. Billingsella retroflexa (Matthew). Plate XC, figures 1, la-h. Not Gonambonites plana retroflexa de Veeneuil [Pander, 1830, Beitrage zur Geognosie des russischen Reiches, p. 77, PI. XXV, figs. 1 and 2]. Clitambonites {Gonambonites) plana retroflexa Matthew, 1895, Trans. Roy. Soc. Canada for 1895, 2d ser., vol. 1, sec. 4, No. 13, p. 267, PI. II, figs. la-c. (Original description of Gonambonites plana retroflexa by de Vemeuil [Pander, 1830, p. 77] copied and variety from Cape Breton described and discussed. The specimens represented by figures la and lb are redrawn in this monograph, PI. XC, figs. Ig and If, respectively.) Clitambonites planus retroflexus (Matthew), Schuchert, 1897, Bull. U. S. Geol. Survey No. 87, p. 184. (Merely changes generic reference.) Billingsella retroflexa Matthew, 1903, Geol. Survey Canada, Rept. Cambrian Rocks Cape Breton, pp. 148-151, PI. X, figs. 2a-e. (Described and discussed. Figs. 2a, 2c, and 2e are copied from Matthew, 1895b, PL II, figs. la-c, respectively. The specimens represented by figs. 2a, 2c, and 2d are redrawn in this monograph, PI. LX, figs. Ig, If, and Ic, respectively.) Orthis (Plectorthis) retroflexa (Matthew), Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 270-271. (Characterized and discussed essentially as below.) This species is distinguished by the fine radiating costse on the ventral valve (PL XC, figs. 1, la-c) and coarser costse on the dorsal (fig. If). The fine longitudinal striae on the costaB are shown by figure le. The latter are similar to those of Eoorthis remnicha (PI. XCII fig. 2c). All that could be definitely determined of the interior of the valves in the type material sent me by Matthew is shown by figures If, Ig, and Ih. In figure Ig of the ventral valve the casts of the pseudospondyHum, area, and base of the main vascular sinuses are shown. In figure If of the dorsal valve the casts of the strong cardinal process, dental sockets, and crura are shown, and in figure Ih the ovarian areas and the visceral area between them. Matthew [1903, p. 148] describes other features of the interior of the valves. The character of the costse and general features of this shell, as far as known, appear to class it with Billingsella romingeri (Barrande) (PI. XC) and B. coloradoensis (Shumard) (PL LXXXV). Matthew's very full description [Matthew, 1903, pp. I48-I5I] should be read by the student of this species. By inadvertence [Walcott, 1905a, p. 270] I referred it to Orthis (Plec- torthis), a name which I was then using to include those forms which are now placed under Eoorthis. Formation and locality. — Uiddle Cambrian: (307d [Matthew, 1903, p. 149]) Sandy limestone of Matthew's [1903, p. 19] Etcheminian, on Young (McFees) Point, near George River, Cape Breton, Nova Scotia. Billingsella eichthofeni Walcott. Plate LXXXIX, figure 1. Billingsella richthofeni Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 242-243. (Characterized and discussed as below as a new species.) This species is represented by two specimens of the exterior of the ventral valve measuring 4 and 5 mm., respectively, in length and width, these being about the same. The outer sur- face is marked by fine, obscure, radiating ribs and very fine concentric strise. The general 762 CAIVIBRIAN BRACHIOPODA. form is much like that of the ventral valve of Billingsella pwnpellyi. It differs from the latter in haAdng a shorter liinge line in proportion to the width, in the more uniform and stronger convexity of the surface, and in the more elevated apex. The species is named after Dr. Ferdinand von Richthofen. Formation and locality.— Lower Cambrian: (C3) Lower part of the Manto shale [Blackwelder, 1907a, p. 28 (list of fossils at bottom of page), and fig. 8a (bed 20), p. 28] 2.5 miles (4 km.) southwest of Yenchuang, Sintai district. Shantung, China. A single specimen of a fragmentary ventral valve that may belong to this species occurs in the following localitj': Lower Cambrian: (C20) Central part of the Manto shale [Blackwelder, 1907a, p. 26 (last list of fossils), and fig. 6 (bed 14), p. 25] on the west side of an isolated butte 1 mile (1.6 km.) south of Changhia, Shantung, China. Billingsella eomingeri (Barrande). Plate XC, figures 2, 2a-n. Orthis romingeri Baeeande, 1848, Naturw. Abhandl., von Haidmger, Bd. 2, Abth. 1, No. 5, p. 203, PI. XVIII, figs. 5a-d. (Described and discussed in German as a new species.) Orthis romingeri Barrande, 1879, Systeme silurien du centre de la Boh@me, vol. 5, pt. 1, PI. LXII, figs, ii: 1-4. (Figs. 3a, 3c, 3b, 3d, and 3e are copied in this monograph, PI. XC, figs. 2, 2a-d, respectively.) Orthis romingeri Barrande, Pompeckj, 1S96, Jahrb. K.-k. geol. Reichsanstalt, Bd. 45, Hft. 3, pp. 513-514, PI. XV, figs. l-5a. (Described and discussed in German.) Billingsella romingeri (Barrande), Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 243-244. (Described and dis- cussed as below.) Shell transverse, the general outline being irregularly subquadrate to subsemicircular. On the ventral valve the cardinal line slopes toward the beak at a low angle, while in the dorsal valve it is approximately straight. In some shells the greatest width is at the liinge line, while in others it is about the middle of the valve. There is considerable variation in length and breadth, as may be seen by comparing the figures illustrating tliis species. The ventral valve is rather strongly convex and the dorsal valve moderately so. The dorsal valve is slightly flattened from the umbo to the frontal margin, the flattening sometimes taking the form of a shallow depression. A low, broad mesial sinus occurs on the dorsal valve and is strongly marked in the young shells. The surface is marked by rounded, bifurcating, radiating costse crossed by concentric lines of growth and undulating concentric strise. The radiating costse vary in size and character in specimens from the same locality. In some specimens they a-re very regular, while in others there mil be wider interspaces or a variation in the manner of interpolation. The ridges of growth also vary in strength and elevation in different shells. The largest shell in a considerable quantity of material has a length in the ventral valve of 13 mm. and in the dorsal valve of 10 mm., with a width of 15 mm. Cardinal area of ventral valve rather high and slightly incurved. It is marked by transverse striae of growth that cross it parallel to its base; the plane of the area extends backward at an angle of about 10° to the plane of the margin of the shell; the delthyrium is rather large; a deltidium is indicated in some of the casts, but none of the specimens show it clearly. The cardinal area of the dorsal valve is about one-half the length of that of the ventral valve ; it extends backward at an angle of more than 45° to the plane of the margin of the valve and is divided midway by a strong delthyrium which is covered, for a part of its distance at least, by a convex chilidium. The traces of the vascular system in the ventral valves are seen in the main vascular trunks, which extend well forward toward the front margin, where they appear to bifurcate, the inner branch extending toward the median line and the lateral branches apparently connecting with the peripheral canal that arches backward about the ovarian areas between it and the main vascular trunks. No points of attachment of the various muscles in the ventral valve have been observed. The area in which the diductor muscles are attached is well marked in Plate XC, figures 2h and 2i, and the cardinal process of the dorsal valve in figures 2j and 2k. There BILLINGSELLIDiE. 763 are also in the dorsal valve the anterior adductor impressions, as shown in figure 2k. In the interior of the dorsal valve the deltidial cavity separates a small cardinal process or callosity, which is straight (fig. 21) or subtriangular (fig. 2k). The crura are relatively long and very prominent, with distinctly defined dental sockets beside them. Observations. — This species was well illustrated by Barrande [1879a, PI. LXII, fig. ii], and I have copied five of his figures of a specimen showing the two valves imited. In the material of the collections of the Museum of Comparative Zoology, Cambridge, Massachusetts, there is a fine series, illustrating the interior of the ventral and dorsal valves, that, through the kindness of Dr. Alexander Agassiz, I was enabled to study and illustrate. The species in its external and internal shape varies so decidedly from all described forms that it is not necessary to point out differences between them. The specific name was given in honor of Dr. Carl Rominger. Formation and locality. — Middle Cambrian: (345 [Pompeckj, lS96b, p. 509]) a Greenish shale in t'ho Paradox- ides zone, on the Dlouha Hora, above tlie brook of Sbirov, near Skrej ; (345c) a in shales of Etage C at Mleschitz ; (345f ) in Etage C [Barrande, 1879a, PL LXII], near Skrej; (345g) in Etage C [Barrande, lS79a, PI . LXII], at Praschno Augezd ; (3451)» shales of Etage C at Jinec ; and (345h) in Etage C [Barrande, lS79a, PI. LXII], at Slap; allin Bohemia, Austria- Hungary. BiLLINGSELLA SALEMENSIS (Walcott). Plate LXXXVII, figures 3, 3a. Orthis salemensis Walcott, 1887, Am. Jour. Sci., 3d ser., vol. 34, pp. 190-191, PI. I, figs. 17 and 17a. (Described and discussed as below as a new species. The specimens represented by figs. 17 and 17a are redrawn in this mono- graph, PI. LXXXVII, figs. 3 and 3a, respectively.) Orthis salemensis Walcott, Oehlert, 1889, Aimuaire g6ologique ujiiversel for 1888, tome 5, 1889, p. 1139. (Described in French.) Orthis salemensis Walcott, 1891, Tenth Ann. Kept. U. is. Geol. Survey, pp. 612-613, PI. LXXII, figs. 6 and 6a. (The text and figures are copied from Walcott, 1887, pp. 190-191, PL I, figs. 17 and 17a, respectively,) Billingsella salemensis Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 245. (Text copied fi-om Walcott, 1887, pp. 190-191.) Shell about the average size of the Cambrian species of the genus. Transversely subquad- rilateral; front broadly rounded and slightly sinuate midway; hinge line as long as the greatest width of the shell. Ventral valve convex, most elevated about one-fourth the distance from the beak to the anterior margin; beak small and incurved to the margin of the medium-sized area; the surface "of the area and the foramen have not been observed; mesial sinus broad and shallow, it is marked by a low median rib and laterally by two costse on each side, a third appearing just outside the sinus. The dorsal valve, associated in the same hand specimen of limestoiie, is slightly more convex; frontal margin with a rather deep sinuosity to receive the projection of the ventral Talve; median fold broad and but slightly elevated, marked by two or three low costse; the beak appears in the broken specimen in the collection to be scarcely elevated above the surface of the shell, and to terminate at the cardinal margin; area unknown. The surface of both valves is marked by fine concentric lines of growth, and low, rounded costse, varying in number from six or seven, as in the specimens figured, to twelve to fourteen in other specimens. In the broad costse and the general aspect of the shell this species is unake any known to me from the Cambrian, ^vith the exception of Billingsella wMtfieldi (Walcott), from which, however, it differs in strength and character of costffi and outline of valves. The specific name is derived from Salem, New York. Formation and locality. — Lower Cambrian: (319b) Conglomeratic limestones at St. Simon; and (3191i) lime- stone bowlders in conglomerate at Metis on the St. Lawrence below Quebec; both in the Province of Quebec, Canada. a These localities are represented in the collections of the United States National Museum. 764 CAi'IBRIAN BRACHIOPODA. (2b) Limestone just north of Beman Park, in the northeastern part of the city of Troy, Troy quadrangle (U. S. Geol. Survey), Rensselaer County; (23a) limestone in Penrhyn quarries, Middle Granville, Mettawee quadrangle (U. S. Geol. Survey), Washington County; and (367a) limestone about 0.33 mile (0.5 km.) south of John Hulett's farmhouse, 3 miles (4.8 km.) west of South Granville and 4.5 miles (7.2 km.) southwest of Granville, Fort Ann quad- rangle (U. S. Geol. Survey); all in New York. (338d) Limestone 1 mile (1.6 km.) south of Shushan; (21 and 37)shales and limestone 1.5 miles (2.4 km.) south of Salem; (36) limestone 1 mile (1.6 km.) south of Shushan and 3.5 miles (5.6 1cm.) north-northeast of Cambridge; and (33) limestone on the roadside near Rock Hill schoolhouse, near North Greenwich, about 5 miles (8 km.) northwest of Green- wich; all in the Cambridge quadrangle (U. S. Geol. Smvey), Washington County, New York. Specimens that are doubtfully referred to this species occur at the following locality, the stratigrapliic horizon of which is doubtful : lower Cambrian : (367b) Sandstone at Lansingburg, north of Troy, Cohoes quadrangle (U. S. Geol. Survey), Rensselaer County, New York. BiLLINGSELLA STRIATA Walcott. Plate LXXXVI, figures 4, 4a-c. Sillingsella striata Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 245. (Characterized as below as a new species.) The form of the ventral valve of this species is much like that of Billingsella plicatella. It differs- in having a finely striated outer surface, and in the strong development of the main vascular sinuses, and the broader deltidial cavity. The only two specimens of the dorsal valve are nearly flat. Formation and locality. — Middle Cambrian: (149a) Limestone at the forks of Pole Creek, above Cherry Creek basin, Threeforks quadrangle (U. S. Geol. Survey), Madison County, Montana. Billingsella whitfieldi (Walcott). Plate LXXXVI, figures 5, 5a. Kutorgina whitfieldi Walcott, 1884, Mon. U. S. Geol. Survey, vol. 8, pp. 18-19, PI. IX, figs. 4, 4a-b. (Described and discussed essentially as below as a new species. The specimens represented by figs. 4, 4a-b are redrawn in this monograph, PL LXXXVI, figs. 5 and 5a, respectively.) Billingsella whitfieldi (Walcott), Schuchebt, 1897, Bull. U. S. Geol. Survey No. 87, p. 159. (Merely^ changes generic reference.) Billingsella whitfieldi Walcott, 1905, Proc. U. S. Nat Mus., vol. 28, p. 246. (Described and discussed as below, an almost exact copy of the original description, Walcott 1884b, pp. 18-19.) Shell convex, hinge Hne straight and a little less than the greatest width of the shell, sides rounding regularly into the slightly convex frontal margin. Ventral valve fairly convex, elevated along the center to form a flat depressed fold, and sloping somewhat rapidly from this to the lateral and cardinal margins ; median elevation with about five rather faintly defined, simple plications, that reach up to the higher portion of the valve; beak small, a little depressed, and rising above the area; cardinal margins straight and diverging from the beak at an obtuse angle; character of area unknown. Dorsal valve depressed convex, with a rather wide, shallow median depression, and two short plications on each side of it toward the front, which are obsolete in some of the specimens; the area between the cardinal edges and the elevation of the sides of the mesial depression is depressed and corresponds to the flattened lateral slope of the ventral valve. Surface marked by fine, very clearly defined concentric striae that are crowded together into narrow ridges, and are subparallel to the front and lateral margins of the shell. Billingsella whitfieldi belongs with the group of species including B. salemensis , or shells with coarse phcations and very fine concentric striae. The latter species occurs with the Olenel- lus fauna in eastern New York, and B. whitfieldi in the Middle Cambrian of central Nevada. The specific name was given in honor of R. P. Whitfield. Formation and locality. — Middle Cambrian : (65b) Top of the Eldorado limestone [see Walcott, 190Sf, p. 1841, west side of Secret Canyon; and (55) shaly limestone at the top of the Eldorado limestone [Walcott, 1908f, p. 184], east slope of Prospect Mountain, in New York Canyon; both in the Eureka district [Hague, 1892, Atlas], Eureka County, Nevada. BILLINGSELLIDiE. 765 Genus ORTTSIA Walcott.o Orihis {Orusia) Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 273. (Characterized and discussed essentially aa below as a new subgenus.) Orusia Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 4, PI. XI, and pp. 142 and 148. (Classification of genus.) OrtTiis lenticularis of authors is not an OrtJiis as restricted by Hall and Clarke [1892c, pp. 192-194]. It appears to belong more nearly to the group of species assembled under Eoorthis. It departs from EoortTiis in its very thia shell, subequally convex valves, small umbonal cavity, and wide variation in form and surface characters. Type. — Anomites lenticularis Wahlenberg [1821, p. 66]. Orusia? eurekensis (Walcott). Plate CI, figures 7, 7a. Orthis eurekensis Walcott, 1884, Mon. U. S. Geol. Survey, vol. 8, pp. 22-23, PI. IX, figs. 8 and 8a. (Described as a new species. The specimens represented by figs. 8 and 8a are redrawn Ln this monograph, PL CI, figs. 7a and 7, respectively.) Protorthis? eurekensis (Walcott), Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, p. 232. (Merely changes generic reference.) Orthis? eurekensis Walcott, Schuchert, 1897, Bull. U. S. Geol. Survey No. 87, p. 286. (Merely accepts the original generic reference.) Orthis (Orusiaf) eurekensis Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 277. (Described and discussed as below. General form rounded subquadrate; strongly convex. Surface marked by fine, rounded, radiating ribs, five in the distance of 1 mm. Length of ventral valve, 4 mm.; width, 4.5 ram.; dorsal valve a trifle shorter. Ventral valve with a high median fold over the umbo, that widens and flattens toward the front margin, which is arched to receive the projecting median depression of the dorsal valve. The umbo curves over to the apex, which overhangs the hinge line. Area low and strongly inclined backward. The interior cast shows that there was a thick pseudospondylium, but no details of it are preserved. Dorsal valve with a deep, gently curved median sinus or depression that extends from the umbo to the front margin. In the cast strong anterior adductor muscle scars are shown on the sides of the median depression, and just back of them, in the sinus, what may be the smaUer posterior adductor scars. Observations. — This strongly marked shell suggests some of the more convex shells of Orusia lenticularis (Wahlenberg); it differs in its fine ribs, deep median sinus in the dorsal valve, and the sharp fold of the ventral valve; also in the presence of a tliickened shelf beneath the umbo of the ventral valve that suggests a spondylium; this character, however, is sometimes indicated in 0. lenticularis (PI. XCVIII, figs. Ic and le). The specific name is derived from Eureka district, Nevada. Formation and locality. — Middle Cambrian: (55b) Top of the Eldorado limestone [Walcott, 1908f, p. 184] west side of Secret Canyon, Eureka district [Hague, 1892, Atlas], Eureka County, Nevada. Orusia lenticularis (Wahlenberg). Plate XCVIII, figures 1, la-p, 2, 2a-k, 3, 3a-b, 6, 6a-c. Anomites lenticularis Wahlenberg, 1821, Nova Acta Regise Soc. Sci. TJpsaliensis, vol. 8, Petrificata telluris Svecanse, pp. 66-67. (Described in Latin as a new species; see Matthew, 1892, p. 46, for copy of original, and translation.) Atrypa? lenticularis (Wahlenberg), Dalman, 1828, K. Svensk. Vet.-Acad. Handl. for 1827, pp. 132-133. (Described in Latin; see Matthew, 1892, p. 46, for copy of original, and translation.) a Prior to the definition of tlie genus Orusia the species now placed Anomites Wahlenberg [1821, p. 66]. Atrypa? Dalman [1828, p. 132]. Spirifcra f von Buch [1834, p. 48). Atrypa f Hisinger (1S37, p. 76]. Atrypa Kjerulf [1S57, p. 92; 1865, p. 3]. Orthis Salter [1866, p. 339]. Orthis Davidson (1868, p. 314; 1869, p. 230]. Orthis Kayser [1876, p. 9]. Orthis Roemer [1876, PI. II, figs. 4a-c]. under that genus were referred to the following genera: Atrypa Kjerulf [1879, PI. XIII]. OrtUs Salter and Etheridge [1881, p. 644]. Orthis Brogger [1882, p. 48]. Orthis Walcott [lS84b, p. 22]. Orthis Roemer [1SS5, p. 33]. Orthis Matthew [1892, pp. 46, 48, and 49). Prolnrthis? Hall and Clarke [1892o, p. 232]. OrtAis? Schuchert [1897, p. 286]. Orthis Matthew [1903, pp. 213, 216, and 217]. 766 CAMBRIAN BRACHIOPODA. Spiriferaf lenticularis (Wahlenberg), von Buch, 1834, Physikal. Abhandl. K. Akad. Wiss. Berlin, p. 48, PI. I, figa. 13 and 14. (Described in German; see Matthew, 1892, p. 47, for translation.) Atrypa? lenticularis (Wahlenberg) Hisinger, 1837, Lethsea Svecica, p. 76. (Not seen.) Atrypa lenticularis (Wahlenberg), Kjeeulf, 1857, Geologie des sildlichen Norwegens, p. 92. (Locality mentioned in German.) Atrypa lenticularis (Wahlenberg), Kjerulf, 1865, Veiviser ved Geologiske Excursioner i Christiania Omegn, p. 1, and figs. 7a-d, p. 3. (Mentioned and locality given in Norwegian.) Orthis lenticularis (Wahlenberg), Salter, 1866, Mem. Geol. Survey Great Britain, vol. 3, p. 339, PI. IV, figs. 8-10. (Described and discussed; see Matthew, 1892, p. 47, for copy.) Orthis lenticularis (Wahlenberg), Davidson, 1868, Geol. Mag., vol. 5, p. 314, PI. XVI, figs. 20-22. (Occurrence men- tioned and new localities given.) Orthi'! lenticularis (Wahlenberg), Davidson, 1869, British Fossil Brachiopoda, vol. 3, pt. 7, No. 3, pp. 230-232, PI. XXXIII, figs. 22-28. (Described and discussed, copying Wahlenberg's original description in Latin, 1821, p. 66. Figs. 22, 23 and 24, and 25 are copied from Salter, 1866, PL IV, figs. 9a, 9b, and 9c, respectively; figs. 28 and 28a are copied from Davidson, 1S6S, PL XVI, figs. 22 and 22a; and figs. 26, 26a-b are redrawn from the specimen figured by Davidson, 1868, PL XVI, figs. 21 and 21a.) Orthis lenticularis (Wahlenberg)?, Kaysek, 1876, Beitrage zur Geologie und Palseontologie der argentinischen Bepub- lik, vol. 2, Paleontologischen Theil, Abth. 1, p. 9, PL I, figs. 11 and 12. (Characterized and discussed in German; see pp. 767-768 for translation.) Orthis sp., Kayser, 1876, idem, p. 9, PL I, fig. 13. (Characterized in German; see p. 768 for translation.) Orthis lenticularis (Wahlenberg), Roemer, 1876, Lethsea geognostica, pt. 1, Lethsea palseozoica. Atlas, PL II, figs. 4a-c. (No text reference. Fig. 4a is copied from Salter, 1866, PL IV, fig. 9a; figs. 4b and 4c are copied from David- son, 1869, PL XXXIII, figs. 26b and 26a, respectively.) Atrypa lenticularis (Wahlenberg), Kjerulf, 1879, Sydlige Norges Geologi, atlas, PL XIII. (Gives position in vertical section.) Orthis lenticularis (Wahlenberg), Salter and Etheridge, 1881, Mem. Geol. Survey Great Britain, vol. 3, 2d ed., pp. 544-545, PL IV, figs. 8-10. (Text and figures copied from Salter, 1866, p. 339, PL IV, figs. 8-10.) Orthis lenticularis (Wahlenberg), Brogger, 1882, Die silurischen Etagen 2 und 3, p. 48. (Specimens from new locali- ties discussed in German.) Orthis lenticularis (Wahlenberg), Roemer, 1885, Paleontologische Abhandlungen von Dames und Kayser, Bd. 2, Hft. 5, pp. 33-34 (280-281), PL I (XXIV), figs. 9a-c. (Occurrences of the species discussed in German. Fig. 9a is copied from Salter, 1866, PL IV, fig. 9a; figs. 9b and 9c are copied from Davidson, 1869, PL XXXIII, figs. 26b and 26a, respectively.) Orthis lenticularis (Wahlenberg), Matthew, 1892, Trans. Roy. Soc. Canada for 1891, vol. 9, sec. 4, No. 5, pp. 46-48, PL XII, figs. 9a-d. (Gives original and translation of Wahlenberg, 1821, p. 66, translations of Dalman, 1828, p. 132, and von Buch, 1834, p. 48, and copy of Salter, 1866, p. 339, and describes and discusses species. Speci- mens from Matthew's material are figured in this monograph, PL XCVIII, figs. 3, 3a-b, but as far as can be determined none of these specimens were figured by Matthew, 1892, PL XII, figs. 9a-d.) Orthis lenticularis strophomenoides Matthew, 1892, idem, p. 49, PL XII, figs. 12a-b. (Characterized and discussed as a new variety. The specimens represented by PL XCVIII, figs. Ic and 2b, of this monograph, are typical of this proposed variety, but they are drawn from material in the collections of the United States National Museum, and are not the type specimens.) Orthis lenticularis (Wahlenberg), Matthew, 1903, Geol. Survey Canada, Rept. Cambrian Rocks Cape Breton, pp. 213-216, PL XVII, figs. la-d. (Text and figures copied from Matthew, 1892, pp. 46^8, PL XII, figs. 9a-d.) Orthis lenticularis strophomenoides Matthew, 1903, idem, p. 217, PL XVII, figs. 4a-b. (Characterized. Figs. 4a-b are copied from Matthew, 1892, PL XII, figs. 12a-b, respectively.) Orthis {Orusia) lenticularis (Wahlenberg), Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 273-276. (Described and discussed essentially as below, giving translation of Kaj^ser's references, 1876, p. 9. Matthew [1892, pp. 46-48], in his excellent review of the descriptions of this species, gives a translation of Wahlenberg's original description, together with the I^atin; also the descrip- tions of Dalman [1828, p. 132], von Buch [1834, p. 48], and Salter [1866, p. 339]. He calls attention [1892, p. 47] to the fact that if the reader will compare the several descrip- tions of this species by the authorities named he will be surprised at the diversity they exhibit. This diversity, Matthew thmks, is due partly to the imperfect descriptions of the earlier writers, but chiefly to the remarkable variability of the species. Matthew recognizes the species in the Upper Cambrian, near St. John, New Brunswick, and has also distinguished three varieties. Through his kindness I had the opportunity of studying the types of the varieties. Through M. Schmalensee, a collector in the Geological Survey of Sweden, I secured a large and fine series of this species from thin bands of limestone in the Olenus and alum shales on Oeland Island and at Hunneberg. I also collected a quantity of the shells in the Upper Cam- brian of Manuels Brook, Newfoundland. From this material an attempt has been made to BILLINGSELLID^. 767 select a series illustrating the great range of variation in form and surface markings, first, from Sweden; second, from Newfoundland; and third, from New Brunswick. I was not able to obtain satisfactory material from Wales, but Davidson's figures [1869, PL XXXIII, figs. 22-28] illustrate fully the peculiarities of the species as it occurs there. The general form of the shell is fairly well shown by the series of figures on Plate XCVIII; also the great variation in surface characters. Only one specimen was found in which the two valves were united (PI. XCVIII, figs. 6, 6a-c). The convexitj^ of the two valves is subequal, the ventral being a trifle greater. The cardinal view (PI. XCVIII, fig. 6c) shows how short the hinge line of both valves is in a specimen where the cardinal extremities are rounded. The side view shows the angle of slope of the areas of the two valves. A very careful search of the casts of the interior was made for the purpose of illustrating the muscle scars and vascular markings, and in a few mstances traces of these have been found. In one illustration (PI. XCVTII, fig. le) the area (pseudospondylium) beneath the umbo of the ventral valve is outlined, also the main vascular sinuses; in another (PI. XCVIII, fig. Ip), drawn from the cast of a small ventral valve, the area, main vascular sinuses, and the details of the umbonal cavity are clearly shown. The backward extension of the cast of the grooves occupied by the sinuses to the apex of the cavity is verj^ distinct ; also the area between them occupied by the path of advance of the scars of the adductor muscles. Matthew [1892, PI. XII] illustrates some traces of the vascular markings and muscle scars, but they are almost too indefinite to be of value. In a single specimen of the ventral valve from Oeland Island (PI. XCVIII, fig. Ip) the cast of the umbonal cavity is nearly as sharp as in some specimens of EoortJiis remnicha. The cavity is tripartite (PI. XCVIII, fig. Ic), the central division being occupied by the diductor muscle scars, and the two lateral divisions are contiauous with the ridges representing the casts of the main vascular siauses. I have been unable to secure any illustrations to show clearly whether there is a deltidium present or not. The delthyrium is clearly shown in several specimens. Casts of the interior of the dorsal valve from Newfoundland (PL XCVIII, figs. 2f and 2h) show the presence of crural plates that extend to the bottom of the valve; also short but very definite crura and small depressions beside the latter for the reception of the teeth, of the ventral valve. A cast of the ventral valve (PL XCVIII, fig. 2d) shows that the dental plates extend to the bottom of the valve; and specimens from Sweden (PL XCVIII, figs. Ic and le) show that in certain individual ventral valves the dental plates and a transverse arching ridge sharply define the umbonal cavity. The average size of the specimens from Oeland Island is about 5 by 6 mm. One dorsal valve is 7 bj' 9 mm. Those from Hunneberg average from 5 to 6 mm., with occasional shells 7 by 8 mm. In Newfoundland great numbers measure 4 by 5 mm., and some have a length of 10 mm. and a width of 12 mm. Matthew [1892, p. 48] states that the average size of the shells in the Acadian rocks is about 5 by 6 mm. Brogger [1882, p. 48] mentions an example from Toien, Christiania, Norway, measuring 10.5 mm. by 12.5 mm. I have not attempted any detailed description of the species, as it is so variable in form and surface marldngs. An attempt was made to determine varieties in the material from Sweden and Newfoundland, but there was such a gradation in all of the characters upon which such difl'erentiation might rest that it was finally abandoned. Matthew [1892, p. 48] considers that he has reason for establishing varieties among the New Brunswick forms. Whether these would be of value if a large amount of material were available for comparison is doubtful. Kayser [1876, PL I, figs. 11 and 12] illustrates a shell that is apparently identical with Orusia lenticularis, which occurs in the sandstone at TUcuya, Province of Jujuy, Argentina, in association with Olenus, Agnostus, etc. He also illustrates [1876, PL I, fig. 13] a dorsal valve of a small Orthis that in many respects looks more hke 0. lenticularis than figures 11 and 12 of the same work. I very much doubt if they represent this species; in fact, Kayser questions his identification by an interrogation mark. He says of the shell [1876, p. 9]: Another, much smaller, Orthis species occurs in the fine-grained sandstones of Tilcuya, associated with Olenus, Agnostus, Arionellus, Theca, and Orthis saHensis, which has just been described. The smaller Orthis species is 768 CAIVIBRIAN BRACHIOPODA. transversely oval in outline, with straight hinge edge, corresponding to the greatest breadth of the shell. The ventral valve is moderately arched, the dorsal somewhat less. The surface of both valves is covered with comparatively strong ribs, arranged in bundles. On the middle of the ventral valve there is an especially well-marked rib or bundle of ribs. Corresponding to this on the dorsal valve there is a well-marked sinus, limited on each side by a strong bundle of ribs. The form just described agrees in the main so well with the figures given by Salter and Davidson of the small English form identified with Wahlenberg's lenticularis that I can hardly doubt its specific identity with the latter. Of OrtMs sp. Kayser remarks [1876, p. 9]: Before me lies a cast from Tilcuya, representing a third Orthis species. It is almost equal in size to 0. saltensis, but differs from it in outline, which is greatly prolonged transversely, the greatest breadth at the hinge edge, and the feeble winglike projection of the hinge corners. This last-named characteristic and the much larger dimensions also distinguish this fossil from 0. lenticularis. The surface of the shell has been covered with very strong bundles of ribs. Matthew [1892, pp. 48-49] has named three varieties of Orusia lenticularis. I find essen- tially the same forms in the collections from Sweden and Newfoundland. Two of the varieties, Orusia lenticularis atrypoides and 0. lenticularis lyncioides, have been illustrated in this mono- graph from Matthew's type specimens. The third variety, Orusia lenticularis strophomenoides, occurs associated with specimens of Orusia lenticularis in the Swedish material, and does not appear to be of varietal value. It is illustrated in this monograph by Plate XCVIII, figures Ic and 2b. Formation and locality. — Upper Cambrian: (9f) Limestones of the Olenus zone at Ncersnses, west of Chris- tiania; (3231) with Parabolina spinulosa at Toien, about 1 mile (1.6 km.) northeast of Christiania; (323m) Etage 2b at Oslo, about 1 mile (1.6 km.) southeast of Christiania; (323n [Brogger, 1882, p. 48]) Etage 2b at Vestfossen, 10 miles (16.1 km.) west-southwest of Christiania; (323o) <» Etage 2b, in the city of Christiania; (323p) Etage 2b at Slemmestad, about 3 miles (4.8 km.) southwest of Christiania; (323(i [Brogger, 1882, p. 101]) Etage 2b at Kartveit. in the Christiania region; (323r) « Etage 2b at Krekling, in Sandsvar; (323s) "■ Etage 2b at Gjogrefos, in Sandsvar; (323t) Etage 2b in Hedemarken, east of Lake Mjosen (Miosen), about 40 miles (64 km.) north-northeast of Christiania; (323u) " llfetage 2b at Oxna (Oksna), valley of Glommen River; and (323v [Davidson, 1869, p. 231]) at Egeberg {about 1.5 miles (2.4 1cm.) southeast of Christiana?); all in Norway. (310a) Shales of Olenus truncatus zone, Oeland Island; (390n) limestones of Olenus zone at Hunneberg, western boundary of the Province of Skaraborg; (309m) limestones forming 3c of the Olenus series atAlunbruk (alum works), southern part of Oeland Island; (390o) arenaceous shales at Andrarum, 20 miles (32 km.) northwest of Simrishamn, Province of Christianstad; and (390p [Davidson, 1869, p. 231]) at Kinnekulle, northeast of Lidkoping, Province of Skaraborg; all in Sweden. Drift bowlders of gray bituminous limestone at the following localities [Roemer, 1885, pp. 33 and 34]: (386e) Between Vistula and Elbe rivers, in Schleswig-Holstein and Mecklenburg-Schwerin; (386f) near Wismar, Mecklen- burg-Schwerin; (386g) near Rostock, Mecklenburg-Schwerin; and (386h) near Meseritz, Province of Posen; all in Germany. Upper Lingula flags at the following localities: (318s) b Ogof-ddu Cliff, Carnarvonshire; (366s) 5 miles (8 km.) east of Ffestiniog, Merionethshire; (318t) b Penmorfa Church, Tremadoc, Carnarvonshire; (318u) b Gwerny-y-Barcud; (318V)'' Rhiwfelyn; (318) b Penmain Pool, west of Dolgelly, Merionethshire; (318a) & Criccieth, Carnarvonshire; and (318b [Davidson, 1869, p. 232]), near Portmadoc, Carnarvonshire; all in North Wales. (3) Shaly limestone 300 feet (91.4 m.) above the Paradoxides zone; and (6v) shaly limestones 325 feet ("99.1 m.) above the Middle Cambrian; both on Manuels Brook, Conception Bay, Newfoundland. (3141) Shale picked up on beach in Smith Sound, Trinity Bay, Newfoundland. (lOh) Shale on small east branch of Barachois River, 0.75 mile (1.2 km.) north of the crossroad from Boisdale to Upper Leitches Creek; (135) shales of the Bretonian division of Matthew's [1903, p. 45] section on Gillis Brook, East Bay; (307h) c in Division C3b? (possibly C3c) of Matthew's section, on McLeod Brook=Barachois River; (307i) c in Division C3b of Matthew's section on McNeil Brook, east of Mira River; (307])!= limestone in Division C3b? (pos- sibly CSc) on East Bay, east of Bras d'Or Lake; and (307 1) c limestone in Division C3b? (possibly C3c) on Gillis Brook; all in eastern Cape Breton, Nova Scotia. Limestone lentils in black shales of Division C3a of Matthew's section at the following localities: (308b [Mat- thew, 1892, p. 48]) on Germaine Street, St. John; and (308f)<; on King Street, St. John; both in St. John County, New Brunswick. (389b [Kayser, 1876, p. 9]) Sandstone at Tilcuya, Province of Jujuy, Argentina, South America. Middle Cambrian : (55b) Top of the Eldorado limestone [Walcott, 1908f, p. 184], west side of Secret Canyon, Eureka district [Hague, 1892, Atlas], Eureka County, Nevada. (320f) Limestone at Andrarum, 20 miles (32 km.) northwest of Simrishamn, Province of Christianstad, Sweden. a Brogger, 1882, p. 4. 6 Davidson, 1868, p, 314. c Matthew, 1903, p. 216. BILLINGSELLID^. 769 Oeusia lenticulaeis atetpoides (Matthew). Plate XCVIII, figure 5. Orthis lenticularis atrypoides Matthew, 1892, Trans. Roy. Soc. Canada for 1891, vol. 9, sec. 4, No. 5, p. 48, PI. XII figs, lla-b. (Characterized as a new variety; see below for copy. The specimen represented by fig. 11a is redrawn in this monograph, PI. XCVIII, fig. 5.) Orthis lenticularis atrypoides Matthew, 1903, Geol. Survey Canada, Rept. Cambrian Rocks Cape Breton, p. 217 PI. XVII, figs. 3a-b. (Characterized. Figs. 3a-b are copied from Matthew, 1892, PI. XII, figs, lla-b, respec- tively.) Orthis (Orusia) lenticularis atrypoides (Matthew), Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 276. fOrio-inal characterization copied as below.) The original description by Matthew follows: This form is comparatively smooth, though the ventral valve is sometimes concentrically wrinkled. This valve is distinguished by a medlar -idge and somewhat flattened sides, and the dorsal valve has an unusually deep sinus. Size of the known examples, 6 by 6 mm., and 5 by 6 mm. for the two valves. Formation and locality.— Tipper Cambrian: (308b [Matthew, 1892, p. 48]) Limestone lentils in black shales of Division C3a of Matthew's section, Germaine Street, St. John, St. John County, New Brunswick, Canada. Oeusia lenticulaeis lyncioides (Matthew). Plate XCVIII, figure 4. Orthis lenticularis lyncioides Matthew, 1892, Trans. Roy. Soc. Canada for 1891, vol. 9, sec. 4, No. 5, p. 49, PI. XII figs. lOa-c. (Characterized as a new variety; see below for copy. The specimen represented by fio-. lOa is redrawn in this monograph, PI. XCVIII, fig. 4.) Orthis lenticularis lyncioides Matthew, 1903, Geol. Survey Canada, Rept. Cambrian Rocks Cape Breton, p. 216 PI. XVII, figs. 2a-c. (Characterized. Figs. 2a-c are copied from Matthew, 1892, PI. XII, figs. lOa-c, respec- tively.) Orthis (Orusia) lenticularis lyncioides (Matthew), Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 277. (Original characterization copied as below.) The original description by Matthew follows : Distinguished by its sharp, strong, radiating ribs, large umbo, and high cardinal area. In some of the laro-er examples the radiating ribs become subordinate to and are replaced on the newer part of the shell by concentric strite reversing the usual position of the ribbed and the smooth parts of the shells of this species. Size of the valves about 6 by 8 mm. I have illustrated a ventral valve from Matthew's material that is the most strongly marked. The ventral valves are similar to those from Newfoundland represented by Plate XCVIII, figures 2h and 2i. Formation and locality.— Upper Cambrian: (308b [Matthew, 1892, p. 49]) Limestone lentilea in black shales of Division C3a of Matthew's section, Germaine Street, St. John, St. John County, New Brunswick, Canada. Genus OTUSIA Walcott." Billingsella (Otusia) Walcott. 1905, Proc. U. S. Nat. Mus., vol. 28, p. 246. (Mentioned as a new subgenus.) Otusia Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 4, PL XI, and pp. 142 and 148. (Classification of genus.) This name was proposed [1905a, p. 246] to include " Orthis sandbergi" of N, H. Winchell, which was the only species known at the time the genus was named. One new species, Otusia utahensis, has been added since. The generic and specific characters are included in the descrip- tion of the species. Otusia sandbeegi (N. H. Winchell). Plate XCIII, figures 4, 4a-d. Orthis sandbergi N. H. Winchell, 1886, Fourteenth Ann. Rept. Geol. and Nat. Hist. Survey Minnesota, p. 318, PI. II, figs. 8 and 9. (Described as a new species.) Orthis {"?) sandbergiWincheW, Walcott, 1899, Mon. U. S. Geol. Siu-vey, vol. 32, pt. 2, pp. 452-453, PI. LXI, figs, 2, 2a-d. (Described and discussed as on p. 770. Figs. 2, 2a-d are copied in this monograph, PI. XCIII, figs. 4, 4a-d, respectively.) a Prior to the definition of the genus Otusia the type species was described under the genera Orthis N. H. Winchell (1886, p. 31S] and Ortliis ? Walcott [1899, p. 452). 62667°— VOL 51, pt 1—12 49 770 CAilBRIAN BRACHIOPODA. BilKngsella (Otusia) sandbergi (Winchell), Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 246-247. (Described and discussed essentially as in preceding reference, p. 769, and as below.) Shell small, transverse, subquadrate in outline, exclusive of the acute cardinal extremities. Valves slighth' convex, with a straight hinge line longer than the greatest width of the shell; cardinal area narrow, but well developed on each valve and divided by a rather large open delth^Tium. The ventral valve slightly flattened at the cardinal extremities, rising toward the center with a convex triangular swelling, broadening from the narrow beak to the front; beak small, rounded, and extending slightly beyond the hinge line. Dorsal valve flattened at the cardinal extremities, with well-marked rounded ridges rising between them, and a rather broad, well- defined median sinus; beak very small, slightly encroaching upon the hinge line. Surface marked by fine, regular, radiating striae, between which one or more faint interme- diate stride are sometimes visible ; under favorable conditions very fine concentric stride can be seen, and there are also usually present more or less distinctly marked lines of growth. Very little is known of the interior of the ventral valve. Two fragments of the posterior portion show a broad delthyrium, strong teeth, and a broad umbonal cavity opposite the delthyrium. In the ventral valve the area is narrow and divided by a broad delthyrium, which has a strong cardinal process that extends forward nearly three times the length of the area. Anteriorly, it rests on a broad ridge that extends forward, gradually broadening out and disap- pearing at the anterior margin of the shell. In my former description [1899, p. 453] I stated that "the generic character of this species has not been fully ascertained, but the material from the Yellowstone National Park and specimens from the typical locality at Red Wing, Minnesota, lead me to think that this can not be referred to the genus BiUingseUa. It appears to be an Orthis of the Plectorthis group of Hall and Clarke." A closer study of this species and the forms referred to BiUingseUa led me [1905a, p. 246] to refer it to Otusia on account of its surface characters, the character of the del- thyrium in the two valves, and the strong cardinal process and median ridge in the dorsal valve. A comparison of the specimens of this species from the type locality at Red Wing, Min- nesota, with those from the Yellowstone National Park shows the two shells to be specifically identical as far as the comparison of casts in sandstone can be made with well-preserved shells on the surface of limestone. The specific name was given in honor of Dr. J. H. Sandberg, of Red Wing, Minnesota, who first called attention to the type locality of this species. Formation and locality. — tTpper Cambrian: (86a) "St. Croix sandstone^' near Red Wing, Goodhue County, Min- nesota. (302f) Upper part of the Gallatin formation, north side of Elk Pass, between Buffalo and Slough creeks, Yellowstone National Park, Livingston quadrangle (U. S. Geol. Survey), Montana. Otusia tjtahensis n. sp. Plate LXXXIX, figures 3, 3a-c. This species is represented by several fragments of the two valves. One of the specimens, represented by figure 3, indicates the general outline of the ventral valve, and figure 3b that of the dorsal valve. The surface is marked by concentric lines and small ridges of growth and numerous fine, rounded, radiating ribs that increase by the division of the ribs as they are lengthened by the growth of the shell. A shallow median sinus occurs on the dorsal valve, and a rounded median ridge on the ventral valve. The largest dorsal valve has a width of 9 mm. at the hinge line, with a length of about 6 mm. The generic reference is made on account of the general resemblance of this form to Otusia sandbergi (N. H. Winchell). It difl'ers from the latter in outline and in the rounded character of the ribs. Formation and locality. — Middle Cambrian: (31c) About 900 feet (274.3 m.) above the Brigham quartzite and 3,300 feet (1,005.8 m.) below the Upper Cambrian in the limestone forming lb of the Ute limestone [AValcott, 1908f, p. 196], in Blacksmith Fork Canyon, about 10 miles (16.1 km.) east of Hyrum, Cache County; (32e) limestone at the BILLINGSELLIDiE. 771 same horizon as that of No. 31c, just south of the south fork of Paradise Dry Canyon (locally known as East Fork), east ofParadise, Cache County; and (33r) limestones faulted against the Cambrian quartzites in a canyon about 1 mile (1.6 km.) east of Cricket Spring, Cricket Range {locally knovjn as the Beaver River Range or the Beaver Mountains), northwest of Blackroch, Millard County; all in Utah. Genus WYNNIA Walcott." TFj/nma Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 4, PI. XI, and pp. 142 and 148. (Classification of genus.) The description of the type species includes all that is known of this genus. The material is poor, but sufRcient to indicate that the species belongs to an undefined genus. It differs from Orthis (restricted) in the presence of the large vascular sinuses of the ventral valve and pointed apex of the dorsal valve. The latter is of the type of the apex of the valves of Nisusia festinata (Billings). From BillingseTla it differs in the absence of dental plates and deltidium in the ventral valve. Type. — Orthis warthi Waagen. The generic name is given in honor of Mr. Arthur B. Wynne, of the Geological Survey of India. Wynnia warthi (Waagen). Text figures 68A-A'; Plate LXXXIX, figures 4, 4a-f. Orthis warthi Waagen, 1891, Mem. Geol. Survey India, Paleontologia Indica, 13th ser., Salt Range Fossils, vol. 4, pt. 2, pp. 102-104, PL I, figs. 12-15, PI. II, figs. 1 and 2. (Described and discussed as a new species. The specimen represented by fig. 12b is redrawn in this monograph, PI. LXXXIX, fig, 4a. The specimen repre- sented by fig. 14 is redrawn in the same position on PI. LXXXIX (fig. 4b) of this monograph and in text fig. 68A'. Different views of the same specimen are shown in this monogi'aph, PI. LXXXIX, fig. 4, and text fig. 68A, both of which drawings are of the same shell in the same position. The text figures are the correct representations in each case. PI. II, figs. 2a, 2b, and 2c, are copied in this monograph, PL LXXXIX^ figs. 4e, 4d, and 4f, respectively.) Shell small, biconvex, subcircular to broad oval in outline. Exterior surface unknown. Cast of interior of ventral valve strongly convex. Apex slightly incurved ,^ y over a rather high area that slopes forward at an angle of "^ about 45° to the hinge line. The area is formed of two ficuee os.- w.^ia »art/.MWaagen). a, cast of narrow sides separated by a large triangular delthyrium interiorofaventraivaive(x4). Thesheiiwas without traces of a deltidium; the narrow, elongate sides ''Z':^:^T'':::a^''ZZZf::^:. are slightly concave and have in the cast a narrow raised a', Posterior view of same specimen, showing margin next to the delthyrium. The dorsal valve is less bfoken-ofl beak. , , J. 1 • j_ 1 £ 1 i!_ j_i The specimen from whicli figures 68A and 68A' convex than the ventral, its area slopes forward from the are drawn is incorrectly llgured on PlateLXXXIX, hinge and at the apex of the valve bends slightlv forward, flgwes 4 and 4b, of this monograph, and is the speci- . . „ , ^ 1 J 1-1 ,.1 X /■ .1 X 't 1 E men figured by Waagen [1891, PI. 11, fig. 14]. It is givmg an effect somewhat like that of the ventraf valve of :rom the upper portion of the "Neoboius beds" at Nisusia festinata (BiUings), only very much reduced. The ^^^'^ ™'' ^ait Range, India (oeoi. survey India, casts of the interior of the ventral valve show two strong vascular sinuses and a faintly defined muscle area. This has an outline not unlike that of the diductor scars in the ventral valve of BillingseTla romingeri (Barrande) (PL XC, fig. 2g). The large main vascular sinuses also extend forward in the same manner in the two species. The illustrations of the interior of the ventral valve of Wynnia warthi (PL LXXXIX, figs. 4 and 4a) fail to show the outline of the muscle area as well as it is shown in the specimen represented by figure 4, so I have inserted text figures 68A.and 68A', which are drawn from the same specimen. The casts of the interior of the dorsal valve show a median depression with a few radiating lines, and a few very fine radiating lines extending from the apex a short distance forward. In addition, by reflected light, the outlines of the anterior and posterior adductor scars can be seen on the posterior half of the valve (PL LXXXIX, fig. 4c). The longest ventral valve in the collection has a length and width of 9 mm. The dorsal valve is a little shorter. a Prior to the definition of thegenns Wynnia the type species was placed under Orlhis [Waagen, 1891, p. 102], 772 CAS'IBRIAN BRACmOPODA. Observations. — Waagen [1891, p. 102] describes this shell at length and also gives a num- ber of illustrations that are more or less diagrammatic. Through the courtesy of Doctor Holland, the director of the Geological Surve}^ of India, I have been able to study the type specimens. I can not see as much in them as Waagen did, but as far as my observations go they agree with his, except that the characters shown on the specimen represented by his figure 15 [1891, PL I] and figure 1 [1891, PI. II] appear to me to be the result of fracture caused by compression of the original shell and not to be muscle scars, etc., as interpreted by Waagen [1891, Pis. I and II]. The differences between this shell and the nearest known forms are mentioned under the description of the genus (see p. 771). The specific name is given in honor of Dr. H. Warth, of the Geological Survey of India. Formation and locality. — Middle Cambrian: (357d [Waagen, 1891, p. 104]) "Concretionary shales of the Khussak group" at several localities between Chel Ilill and Kiura (Khewra), eastern part of Salt Range, India. Subfamily EOORTHIN^ Walcott. Genus EOOBTHIS Walcott. o [iiwc. dawn; and 6pS6c, straight.] Not Plectorthis Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, pp. 194-195. (Characterized as a new genus; see below for copy. This genus, as now restricted, is not known to occur in the Cambrian.) OrtMs (Plectorthis) Walcott [not (Hall and Clarke)], 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 257-259. (Original characterization copied and genus discussed somewhat as below.) Plectorthis Grabau and Shimer (in part) [not Hall and Clarke], 1907, North American Index Fossils, vol. 1, pp. 250 and 251. (Characterized. Includes both true Plectorthis and Eoorthis.) Eoorthis Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, pp. 102-104. (Described and discussed as below as a new genus.) Eoorthis Walcott, 1908, idem, vol. 53, No. 4, PL XI, and pp. 142 and 148. (Classification of genus.) In their subdivision of the genus OrtMs Dalman, Hall and Clarke [1892c, p. 192] restricted the genus OrtMs to the group of which OrtMs callactis Dalman is the type, and, among American forms, OrtMs tricenaria of the Trenton and Hudson faunas. These forms show the existence of a transverse apical plate in the delthyrium of the ventral valve. The name Plectorthis was proposed for a second group, of which OrtMs plicatella was made the type (PL XCVI, figs. 4, 4a), and of this the authors [1892c, p. 194] say: This is a persistent form, which in American faunas, so far as known, is limited to the Trenton and Hudson River formations. While it retains the strong external ribs of the typical Orthis, these are not invariably simple (0. fissicosta Hall; 0. triplicatella Meek; 0. sequivalvis Hall [not Davidson]; 0. jamesi, Hall) (PI. XCVI, figs. 5, 5a-c). Thecardinal area of the pedicle valve is comparatively low and the valves are subequally convex. In the interior, the character of the muscle scars, dental lamelte and cardinal process is essentially the same as in group I (OrtMs), and the minute structure of the shell appears to be in precise agreement with that of 0. calligramma though no evidence of tubulose costse has been observed. In Orthis jamesi, which is placed in this association, there is occasionally a deviation toward the resupinate contoiu' exemplified in group IV (Orthis subquadrata) and group V (Orthis sinuata). In the Cambrian faunas I find a group of species intermediate between the typical forms of Billingsella and of OrtMs, as limited by Hall and Clarke [1892c, p. 193], which I have referred for a long time to Hall and Clarke's PlectortMs, placing that genus as a subgenus of OrtMs. a The synonymy for this genus does not give a complete record of the various genera under which the species now included in Eoorthis were formerly placed; it gives only those references in which the genus is discussed or described. To complete the record for the species taken up in this monograph the following mere geiieric references are listed: Orthis de Verneuil and Bnrrande [1800, p. 532], Orthis Kjerulf [1S6.5, p. 1]. Orthis Barrande [18(i8a, p. 99; 1868b, p. 690]. Orthis Meek [1870, p. 425; 1872, p. 295]. Orthis Mallada [1875, p. 31]. Orthis Kayser [1876, p. 8]. OHhis Remele [1881, p. i;9]. Orthis Brogger [18S2, p. 48]. Orthis Kayser [18S3, p. 34]. Orthis Remele [18S5, p. B]. Orthis Roemer [1885, pp. 3!), 37, and 38]. Ortlds Winchell [18811, p. 317]. Orthis Gagel [1890, pp. 10 and 34]. Orthisina Miattbev! [1892, p. 49]. Slrophomena Matthew [1893, p. 102]. Orthis Pompeckj [1890a, p. 4; 1896b, p. 514]. Rafinesquina? Schuchert [1897, p. 338], Orthis Kayser [1S97, p. 280]. Orthis f Walcott [1899, p. 451]. Orthis Pompeckj [1902, p. 7]. OrtUs Weller (1903, p. 113]. Orthis f Etheridge [1905, p. 249]. Orthis (Plectorthis) Walcott [1906, p. 570]. Orthis (Plectorthis) Moberg and Segerberg [1906, p. 09]. Nisusia Walcott [190Sd, p. 97] (by mistake). BILLINGSELLID^. 773 This Cambrian group of shells which I now refer to a distinct genus may be defined as follows, the type of the genus being "Orthis remnicM" Winchell (Pis. XCI and XCII): Diagnosis. — Shells subquadrate to transversely elongate; with or without median fold and sinus; valves subequally convex. Hinge line straight, usually forming nearly the greatest diameter of the shell. Cardinal extremities broadly angular, rarely acuminate. Surface with radiating ribs and striae which may be crossed by concentric growth lines and strife. The ribs increase by interpolation. The ventral valve has the umbo more or less elevated over a hinge line, the apex acute and usually incurved. The area is rather broad, flat or incurved, and transversely striated. Teeth short and supported by dental plates that extend to the bottom of the valve, boundino' a space (pseudospondylium) including the main vascular sinuses and area of attachment of the adductor muscle scars. Delthyrium open or partly closed by a convex deltidium. The adductor muscle scars are included within a narrow median area beneath the umbo on each side of the median line, and the .diductors in a more or less flabelliform area outside of the main vascular sinuses. Pedicle scars unknown. Dorsal valve with low umbo and slightly incurved apex; area well developed, with a broad delthyrium. Deltidial cavity with a straight, simple, cardinal process. Dental sockets small, with short crura. The adductor muscle scars are small, the anterior being nearer the median ridge, which usually extends forward from the base of the cardinal process. Shell structure dense, with a minutely granular groundmass. Sections vertical to the outer surface, however, show a few laminations of growth, but no fine fibers; sections on the plane of the surface show a few coarse irregular fibers resembling matted wood pulp; a dense granular groundmass that is penetrated here and there by irregular openings of varying size. The openings or pores appear to be confined to one or more lamella of the shell and not to pass through it from inner to outer surface, as in Orthis (DalmaneUa) parva and allied punctate orthoids. The openings are usually indicated by minute scattered dark spots. Type. — Orthis remnicha Winchell. Ohservations. — The Cambrian species referred, to Eoorthis have relatively thin sheUs that retain on the interior surfaces but slight traces of the muscle scars and vascular markings, except in the umbonal cavity. Eoorthis may be distinguished from Orthis (s. s.) by (1) its ribs increasing by interpolation; (2) its strongly defined pseudospondylium; (3) its relatively thin shell; and (4) its dense, nonfibrous shell structure. The last three characters also distinguish it from Plectorthis and other subgenera of Orthis. Eoorthis may be considered as the possible connecting link between BillingseUa and the orthoids of the Ordovician. The geological range of Eoorthis is from the upper portion of the Middle Cambrian through the Upper Cambrian and into the lower portion of the Ordovician. Two of the species from strata referred to the Middle Cambrian are represented by material too imperfect for specific description; they occur with Paradoxides in Bohemia, and it is not improbable that they will be found to belong to some other genus. The remaining one of the three species referred to the Middle Cambrian is E. wichitaensis, which occurs in the upper portion of the Middle Cambrian and base of the Upper Cambrian, and E. hastingsensis, which occurs in the Middle Cambrian (Paradoxides zone). EOOKTHIS AGRESTE (Walcott). Plate LXXXIX, figures 6, 6a. Orthis (Plectorthis) agreste Walcott, 1906, Proc. U. S. Nat. Mus., vol. 30, p. 570. (Described as below as a new species.) Shell transverse, subsemicircular ; a ventral valve 9 mm. in length has a width of 12 mm. and a hinge line 10.5 mm. in length; ventral valve moderately and regularly convex, with the apex curved down to an area that is slightly inclined forward from the hinge line. The details of the cardinal area are unknown. 774 CAMBRIAN BRACHIOPODA. Surface marked by rounded radiating ribs and interspaces, 6 ribs in a space of 3 mm. near the front margin; a few of the ribs bifurcate, but most of them extend from the umbo to the front margin; the ribs are crossed by fine concentric striae and strong hues of growth. Ohservations. — This shell is characterized by its regular convexity and the uniformity of the rounded, radiating ribs. Formation and locality. — Middle Cambrian: (C28) Upper part of the thin-bedded gray limestone at the base of the Changhia formation [Blackwelder, 1907a, p. 32 (first list of fossils), and fig. 6 (bed 20), p. 25] 1 mile (1.6 km.) east-southeast of Changhia, Shantung, China. EooETHis ATAVA (Matthew). Plate XCV, figures 7, 7a-b. Strophomma atava Matthew, 1893, Trans. Roy. Soc. Canada for 1892, 1st ser., vol. 10, sec. 4, No. 7, pp. 102-103, PI. VII, fig. 8a-f. (Described and discussed as a new species; see below for copy. The specimens represented by figs. 8c, 8a, and 8b are redrawn in this monograph, PI. XCV, figg. 7, 7a-b, respectively.) Rafinesquina? atava (Matthew), Schuchert, 1897, Bull. U. S. Geol. Survey No. 87, p. 338. (Merely changes generic reference.) Orthis (Pledorthis?) atava (Matthew), Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 259-260. (Original descrip- tion copied and species discussed as below.) StTophoinena? atava Matthew, Moberg and Segerbeeg, 1906, Medd. fran Lunds Geol. Faltklubb, Ser. B, No. 2 (Aftryck ur K. Fysiografiska Sallskapets Handl., N. F., Bd. 17), PL II, figs. 7, 7a-b. (No text reference. Figs. 7, 7a-b, in common with the remaining figures on PI. II of Moberg and Segerberg's paper, were copied from a preliminary photograph of PI. XCV of this monograph.) The original description by Matthew follows : i Narrow semicircular. Valves slightly arched, rather wider than the hinge line, compressed at the cardinal angles; sides of the valves nearly straight behind, regularly rounded in front. Ventral valve moderately convex, highest and somewhat angulated at the middle of its length. Umbo incon- spicuous and appressed to the very narrow area. Dorsal valve somewhat concave, especially toward the umbo, which is depressed to the general level of the valve. The interior of the ventral valve has characters intermediate between those of Orthis and Strophomena. The ridges inclosing the cardinal muscles are shorter and closer at their extremities than in Strophomena, and the scar of the adductor muscle is broader and shorter, but extends halfway to the front of the valve. There is a low, sharp ridge at the umbo between the branches of the posterior cardinal muscle, and the ventral cavity is faintly outlined in front. Another cast of the ventral valve of a larger individual, perhaps of this species, shows the impressions of the muscles more distinctly; in this the impression of the adductor muscle is much nearer to the hinge, being about two-thirds from the front of the valve. There is a low callus in front of the imprint of the adductor muscle. A partly decorticated example of the dorsal valve exhibits a small bifid scar at the hinge line, due to the adductor muscle. There is no median ridge, such as is found in Orthis, the median sinus being almost obsolete. In front of the impression of the adductor muscle is a small, low callus. Sculpture: This consists of sharply raised, rounded, radiating ridges, slightly crenulated by obscure, transverse lines. These ribs are of varying size, every third or fifth rib being larger than the others. These large ribs extend outward from the umbo, and the smaller ones are intercalated between them, or spring from them. On the dorsal valve there are two main ribs in the sinus of the valve and three others extending to the lateral margins; smaller ribs are intercalated between these. On each side of the group of ribs on the middle third of the shell are four fainter, but more strongly arched groups of ridges which throw off minor ridges at the back, directed toward the lateral mar- gins. On the ventral valve the small ribs are almost all intercalated and do not spring from the back of the primary ribs, as in those of the dorsal valve. Size: Length, 12 mm.; width, 14 mm. Height of area of dorsal valve, 0.5 mm.; of ventral valve, 1 mm. A valve supposed to be of this species is 15 mm. long and 19 mm. wide. • Ohservations. — With the available data this species appears to be quite as near to EoortJiis as any described genus. It does not appear to belong with the typical forms of Strophomena or Rafinesquina. The surface ribs, increasing by interpolation, and possibly bifurcation, and the form of the pseudospondylium in the ventral valve, strongly suggest a relationship with Eoorthis. It will probably require better preserved material to determine satisfactorily the correct generic reference for the species. Formation and locality. — Upper Cambrian: (308a [Matthew, 1893b, p. 103]) Dark shales of division C3a of Matthew's section of the St. John formation. Navy Island, St. John Harbor, St. John County, New Brunswick, Canada. BILLINGSELLID^. 775 EooETHis BAVAEiCA (Barrande), PlateXCVII, figm-e4. Orthis bavarica Bakrande, 1868, Paune silurienne des environs de Hof , en Bavifere, p. 99, fig. 76. (Described in French as a new species; see below for translation. Fig. 76 is reproduced in this monograph, PI. XCVII, fig. 4.) Orthis bavarica Barrande, 1868, Neues Jahrb. fiir Mineralogie for 1868, p. 690, unnumbered plate, fig. 76. (Copy of preceding reference. ) Orthis sp., PoMPBCKj, 1896, Tremadoc Fossilien bei Hof, p. 4. (Discussed in German; see below for statement of probable relationships.) The original description by Barrande follows: This very rare species is only represented by two specimens, reduced to a single valve, of which the less imperfect of the two is figured. It has been deformed by compression, but we recognize that it represents the ventral valve, the beak of which appears remarkably acute and projecting, doubtless by reason of compression. This valve shows a barely indicated sinus, very shallow, but rather broad on the frontal contour. The surface is ornamented with projecting longitudinal strise, close together, most of which end at the beak, but some are bifm'cated in their exten- sion. A trace of some concentric strias is seen. Length, 14 mm. ; breadth, somewhat reduced by compression, 9 mm. Pompeckj [1896a, p. 4] mentions the finding of two impressions of a species of Orthis agreeing in form with E. bavarica (Barrande) at Neuhof, near Hof. The species differs in having a sharper, higher rib intercalated between every three or four finer ribs, while the ribs of E. bavarica are all equally strong. The variation in the strength and number of the ribs in species of Eoorthis is often so great that it may be that the form mentioned by Pompeckj [1896a, p. 4] wiU prove to be only a variation of Eoorthis bavarica. From the description and illustration, I think this species should be referred to Eoorthis. Formation and locality. — Passage beds between the Upper Cambrian and the Ordovician: (303c [Barrande, 1868a, p. 99]) suburbs of Hof; and (303f [Pompeckj, 1896a, pp. 7 and 8]) railway cut near Schellenberg, a little dis- tance back of the railway station at Neuhof, near Hof; both in Bavaria, Germany. Eoorthis CHEisTiANLa: (Kjerulf). Plate XCV, flgui-es 1, la-h. Orthis christianix Kjerulf, 1865, Veiviser ved Geologiske Excursioner i Cliristiania Omegn, p. 1 and figs. 8a-c, p. 3. (Locality given in Norwegian.) Orthis christianise Kjerulf, Brogger (in part), 1882, Die silurischen Etagen 2 und 3, p. 48, PI. X, figs. 14a-c. (Men- tions specimens from both the Ceratopyge slate and Ceratopyge limestone and thus probably includes the two species, Eoorthis christianix and E. daunus. See below.) Orthis (Plectorthis) christianix (Kjerulf), Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 260-261. (Discussed somewhat as below.) Orthis (Plectorthis) christianix (Kjerulf), Moberg and Segerberg (in part), 1906, Medd. fran Lunds Geol. Faltklubb, Ser. B, No. 2 (Aftryck ur K. Fysiografiska Sallskapets Handl., N. F., Bd. 17), p. 69, PI. II, figs. 1, la-h; PI. Ill, figs. 12 and 13. (Described and discussed in Swedish. Includes Eoorthis daunus and E. tullbergi. Figs. 1, la-h, in common with the remaining figures on PI. II of Moberg and Segerberg's paper, were copied fi-om a preliminary photograph of PI. XCV of this monograph.) The general form and character of this shell as it occurs in the shales are shown by the figures illustrating it. It appears to differ from any described species in the peculiarity of the bifurcation of the radiating ribs. In aU the species I have referred to Eoorthis the increase in the number of ribs is by interpolation and not by true bifurcation. In E. christianise the increase is by both methods, as shown by figures la, lb, and Ig. The reference to Eoorthis is somewhat doubtful, as there are not sufficient data to base a reference on the characters of the interior, cardinal areas, or convexity of the valves. I have received a large number of specimens from Norway and Sweden labeled "Orthis christianise." After a study of all the available material only the shells from the argillaceous shale of Russelokken and Toien, Norway, and of Oeland Island, Sweden, appear to belong to the species. The shells in the Ceratopyge limestone {Eoorthis daunus) have ribs that increase in number by interpolation of ribs in the interspaces between the older ribs, and a second species {E. wimani), that occurs in both the shale and the liinestone, has simple ribs with few 776 CMCBRIAN BRACHIOPODA. interpolated beyond the umbo. Another transverse form has simple strong ribs that increase m number by the interpolation of a few new ribs. Brogger's illustrations of this species [1882, PI. X, figs. 14a-c] suggest E. daunus more than the typical form of E. cJiristianise, as I understand and interpret it. "Orthis farva" Dahnan (PL XCVI, figs. 6, 6a-g) has sometimes been referred to E. christianise. Gagel [1890, p. 34] described the form usually found in the limestone, stating that the surface is covered with strong, dichotomous ribs. He found it in drift blocks of the Ceratopyge limestone near Belschwitz, East Prussia; and of glauconitic limestone near Prussian Holland, and near Welilau, East Prussia, Germany. Roemer [1885, p. 36] calls attention in his description of the drift in the North German plain to the fact that Remele [1885, pp. 695-698] was the first to identify with certainty blocks of the Ceratopyge limestone of Sweden in the drift of Germany, the presence of a form like E. christianise being part of the evidence. This sheU is probably E. daunus. Roemer [1885, p. 36] states in description of the Ceratopyge limestone that a small "Orthis {f Orthis christianise. Kjeruh)" predominates. The specific name is derived from Christiania, Norway. Formation and locality. — Upper Cambriaii: (323x) Ceratopyge slate, at Russelohhen; and (323y) Ceratopyge slate at Toien; both, near Christiania, Norway. (310d) Ceratopyge slate, at Borgholm, Oeland Island, Sweden. (309e) Shales of the Acerocare zone at AkarpsmoUa, midway between Kigerod and Rost&nga, Province of Mal- mohus, Sweden. EOORTHIS DAUNUS (Walcott). : Plate XCV, figures 2, 2a-c. Orthis sp. Remele, 1881, Zeitschr. Deutsch. geol. Gesell., Bd. 33, p. 696. (Characterized and compared in German.) Orthis christianise Brogger (in part) [not Kjerulf], 1882, Die silurischen Etagen 2 und 3, p^ 48, PI. X, figs. 14a-c. (Mentions specimens from both the Ceratopyge slate and Ceratopyge limestone and thus probably includes the two species, Eoorthis christianiss and E. daunus.) Orthis christianix Roemer [not Kjerulf], 1885, Paleontologische Abhandlungen von Dames und Kayser, Bd. 2, Hft. 5, pp. 36, 37, and 38. (Mentioned in German, in review of literature.) Orthis christianix Remele [not Kjerulf], 1885, Katalog der beim intern. Geologen-Congresa zu Berlin ausgestellten Geschiebesammlung, p. 6. (Locality mentioned.) Orthis christianix Gagel [not Kjerulf], 1890, Beitr. zur Naturkunde Preussens, von Physikal.-oekonom. Gesell. Konigsberg, No. 6, pp. 10 and 34, PI. 11, figs. 22a-b. (Described and new localities mentioned in German.) Orthis christianix Pompeckj [not Kjerulf], 1902, Neues Jahrb. fUr Mineralogie, Bd. 1, p. 7. (Occurrence mentioned, in German.) Orthis (Plectorthis) daunus Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 261. (Characterized as a new species.) Orthis (Plectorthis) daunus Walcott, Moberg and Sbgerberg, 1906, Medd. Iran Lunds Geol. Faltklubb, Ser. B, No. 2 (Aftryck ur K. Fysiografiska Sallskapets Handl., N. F., Bd. 17), p. 69, PI. II, figs. 2, 2a-c. (Characterized in Swedish. Figs. 2, 2a-c, in common with the remaining figures on PI. II of Moberg and Segerberg's paper, were copied from a preliminary photograph of PI. XCV of this monograph.) The illustrations show the principal characters of this species. It differs -from Eoorthis christianise in having simple ribs that increase in number toward the front and lateral margins of the shell by interpolation of new ribs; no true bifurcation of the ribs was observed. A strong median sinus occurs on specimens of the dorsal valve in both shale and limestone. The shell is fibrous and impunctate. No traces have been seen of the fine, rounded, radiating striae that occur on the broader ribs and interspaces of E. christianise. This species differs from E. wimani in its more transverse form and less simple ribbing of the shell. Moberg and Segerberg [1906, pp. 69-70] regard this form as one of the variations of E. christianise. This may be a correct view, but I am not prepared, after a careful study of the material before me, to accept it. To support such an interpretation we should find, in a very full series of E. christianix from the same bed or matrix, the gradations or varieties that I have named tullbergi and daunus. Formation and locality. — Passage beds between the Upper Cambrian and Ordovician: (386) Drift blocks of Ceratopyge limestone near Belschwitz; (386a) drift blocks of "Glauconite limestone " near Prussian Holland, BILLINGSELLID^. 777 90 miles (145 km.) south-southwest of Konigsberg; and (386b) drift blocks of "Glauconite limestone" near Wehlau, 30 miles (48 km.) east of Konigsberg; all [Gagel, 1890, p. 34] in East Prussia, Germany. (323z) Ceratopyge limestone at Tolen, near Christiania; and (8x) Ceratopyge limestone at Slemmestad, about 3 miles (4.83 km.) southwest of Christiania; both in Norway. (323h) Blue Ceratopyge limestone at Vestfossen; and (323f) lower part of tte Ceratopyge limestone at Vestfossen; both [Brogger, 1882, p. 17] 10 miles (16.1 km.) west-southwest of Christiania, Norway. (310j) Ceratopyge limestone at Borgholm; and (310 [Moberg and Segerberg, 1906, description of PI. Ill]) Ceratopyge limestone (zone 4) at Ottenby; both on Oeland Island, Sweden. EooRTHis DESMOPLEURA (Meek). Plate XCVI, figiu'es 1, la-r. Not Orthis coloradoensis Shumakd, 1860, Trans. Acad. Sci. St. Louis for 1856-1860, vol. 1, p. 627. (Referred in this monograph to Billingsella.) Orthis coloradoensis Meek [not Shumakd], 1870, Proc. Am. Philos. Soc, vol. 11, No. 84, p. 425. (Described as a new species.) Orthis desmopleura Meek, 1872, U. S. Geol. and Geog. Terr., Geol. Survey Wyoming, Prelim. Rept., p. 295. (Merely proposed as a new specific name, coloradoensis being preoccupied.) Orthis (Plectorthis) desmopleura (Meek), Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 261. (Characterized.) This shell has the general form and external characters of E. wicMtaensis (Walcott) . It differs in being less convex and in the details of the radiating ribs. The illustrations of the two species will serve as a basis of comparison. EoortMs desmopleura differs from E. remnicha (N. H. Winchell) in its uniformly smaller size, less convexity, and in the details of the radiating ribs. The ribs have a wide range of variation, but when from the same character of matrix they are all of the same type and the shells grade from one to the other. The ventral valves of young shells 2 to 3 mm. long are highly convex and usually appear to be a little longer than wide; if in such shells the surface striae are in sharply elevated fasciculse, the result is to all appearances a rhynchonelloid shell. The interior of the ventral valve shows a narrow area, broad delthyrium, spondylium almost free from the bottom of the valve, and a median septum that may have supported the front end of the spondyhum. In young and strongly convex shells the spondylium is narrow and very strongly defined. The narrow area of the dorsal valve is divided by a broad delthy- rium, in the center of which is a very slightly developed cardinal process. The Wyoming variety of tliis species occurs in abundance in the Bighorn Mountains. The specimens illustrated on Plate XCVI show the characteristic features of the species as it occurs in Colorado, and also some phases of it not observed there. The typical form is illustrated by figure Ih. For the variety the name of E. desmopleura nympha is used (PI. XCVI, fig. 2). Eoorthis hamhurgensis (Walcott) [1884b, p. 73] is closely related to E. desmopleura and may be identical with it. Eoorthis melita (Hall and Whitfield) [see Leptsena melita Hall and Whit- field, 1877, p. 208] from the Pogonip Lower Ordovician limestone is near to the less convex, more evenly striated forms of E. desmopleura. It is probably not more than a variety of the latter. Schuchert's reference of the species L. melita to Dalmanella [1897, p. 202] does not appear to be correct, as it has the pseudodeltidium of Eoorthis. Formation and locality. — Lower Ordovician: (360f) Siliceous limestone at Glen Eyre, Queens Canyon, north- east of Manitou; (360a) red siliceous limestone on west side of Trout Creek below Bergen Park, 7 miles (11.2 km.) north-northwest of Manitou; (186 and 186a) near line of contact between red and gray Ordovician limestone, in siliceous red limestone about 30 feet (9.1 m.) above the pre-Cambrian rocks, Williams Canyon, Manitou; (187) red siliceous limestone 105 to 122 feet (32 to 36.7 m.) above the pre-Cambrian rocks, 2 miles (3.2 km.) below Manitou Park Hotel; and (360) red siliceous limestone near Colorado Springs; all in El Paso County, Colorado. (lost) Limestone [Walcott, 1908f, p. 173] at the summit of Notch Peak, House Range, Millard County, Utah. (185z) Limestones at the base of the Lower Ordovician [Walcott, 1908f, p. 191] in Blacksmith Fork Canyon, about 9 miles (14.4 km.) east of Hyrum, Cache County, Utah. Passage beds between the Upper Cambrian and the Ordovician: (34g) Limestone about 1,000 feet (305 m.) above the valley on the east side of the Fish Spring Range, just west of the high point southwest of the J. J. Thomas ranch, Tooele County, Utah. 778 CAMBRIAN BRACHIOPODA. Upper Cambrian : (30w) Drift bowlder of limestone supposed to have come from la of the Notch Peak limestone on Notch Peak [Walcott, 190Sf, p. 175], found about 2 miles (3.2 km.) south of Marjum Pass, House Range [Walcott, 190St, PI. XIII], Millard County; (331) limestones in pass between the Pavant Mountains and the Canyon Range, a few hundred yards east of the divide, on the road between Holden and Scipio, Millard County; and (54r) drift pieces of limestone from the west slope of the Wasatch Range, east of the Lakeview ranch, about 5 miles (8 km.) north of Brigham, Boxelder County; all in Utah. (54b) About 1,200 feet (365.8 m.) above the Middle Cambrian and 25 feet (7.6 m.) below the top of the Upper Cam- brian in the upper part of the limestone forming 1 of the St. Charles formation [Walcott, 190Sf, p. 191]; (54c) about 1,100 feet (335.3 m.) above the Middle Cambrian and 120 feet (36.6 m.) below the top of the Upper Cambrian, in the central part of the limestone forming 1 of the St. Chai-les formation [Walcott, 1908f, p. 192]; and (54d) about 1,050 feet (320 m.) above the Middle Cambrian and 175 feet (53.3 m.) below the top of the Upper Cambrian in the lower part of the limestone forming 1 of the St. Charles formation [Walcott, 1908f, p. 192]; all in Blacksmith Fork Canyon, about 10 miles (16.1 km.) east of Hyrum, Cache County, Utah. (158) Limestones north of East Gallatin River, near Hillsdale; and (340b) limestone at the mouth of Fourmile Creek; both in the Threeforks quadrangle (U. S. Geol. Survey), Gallatin County, Montana. (327) Arenaceous limestone east of Gold Camp, in the Caballos Mountains, New Mexico. (14k) Limestone on Wolf Creek, 15 miles (24.2 km.) west-southwest of Sheridan, Bighorn Mountains; and (168) limestone on north side of Tepee Creek, beside the road from Sheridan to Dome Lake, Bighorn Mountains; both in Sheridan County, Wyoming. (346b) Conococheague limestone, 2.75 miles (4.4 km.) south of Mercersburg, Franklin County, Pennsylvania. Specimens that are somewhat doubtfully referred to this species occur at the following localities : Tipper Cambrian: (152) Limestone on ridge between Churn and Cottonwood Canyons, west side of Bridger Range; and (154) limestone in hill on west side of Dry Creek, opposite mouth of Pass Creek, about 5 miles (8 km.) north of Hillsdale, Threeforks quadrangle (U. S. Geol. Survey); both in Gallatin County, Montana. Upper? Cambrian: (306) Sandy limestone on Gravel River, eastern slope of the Rocky Mountains, in the Mackenzie River basin, British Columbia. EOORTHIS DESMOPLEURA NYMPHA (Walcott). Plate XCVI, figure 2. Orthis (Plectorthis) desmopleura nympha Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 262. (Characterized aa below as a new variety.) This variety is based on strongly convex ventral valves in which the surface is marked by fine radiating striae, separated into bands of 3 to 6 strise by stronger and more elevated striae. Some shells show concentric lines and often ridges of growth that give an imbricated appear- ance to the portion of the surface beyond the umbo. Formation and locality. — Lower Ordovician: (186) Near line of contact between red and gray Ordovician limestone, in red siliceous limestone about 30 feet (9.1 m.) above the pre-Cambrian rocks, Williams Canyon, Manitou, El Paso County, Colorado. Upper Cambrian: (168) Limestone on north side of Tepee Creek, near the road from Sheridan to Dome Lake, Bighorn Mountains, northern Wyoming. EOORTHIS ? DIABLO (Walcott) . Plate XCIII, figure 3. Orthis (Plectorthis) diahlo Walcott, 1905, Proc. LT. S. Nat. Mus., vol. 28, p. 262. (Described as below as a new species.) This species is founded on a small, transverse shell that is marked by a few prominent radiating costse that extend from the umbo to the margin of the shell. In the cast the costse have a sharp summit and slope evenly to a narrow space between them. A ventral valve 9 mm. in height has a width of 14 mm., which is about the average propor- tion of the specimens in the collection. The casts of the ventral valve show a rather low area divided by a delthyrium, the inner angles of which have a rather strong tooth. The dental plates extend backward farther than in most species of the genus, becoming attached to the bottom of the valve only near the teeth, and not extending forward as in EoortJiis remnicha to form a pseudospondylium. None of the specimens in the half dozen shells in the collection BILLINGSELLID^. 779 show the muscular or vascuLar markings. There may oi' may not be a mesial depression on either valve. The reference of this species to Eoorthis is made with much reservation. Formation and locality. — Upper Cambrian: (81b) "St. Croix sandstone," near Devils Lake, Sauk County; and (83) "St. Croix sandstone," near Trempealeau, Trempealeau County; both in Wisconsin. EooKTHis DOKis (Walcott). Plate XCVII, figures 13, 13a. Orthis (Plectorthis) doris Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 262-263. (Described and discussed as below as a new species.) Of this species a ventral and dorsal valve occur in the collection. General form rounded subquadrangular. Ventral valve strongly convex, with the greatest height at the umbo, from which the beak arches over a high back war d-inchning area. Dorsal valve much like the ventral in form except that it is less convex and less elevated at the area. Surface of both valves with numerous radiating ribs that have an angular summit and an angular depression between them. The ribs increase in number toward the front by interpola- tion. The ventral valve has a length of 7 mm.; width, 8 mm. The dorsal valve is a little shorter than the ventral. Observations. — This shell is not unlike Eoorthis indianola in form and surface characters. It differs in being more convex and in the absence of a sinus or median fold on either valve. Formation and locality. — Upper Cambrian: (C64) Upper limestone member of the Kiulung group [Black- welder, 1907a, pp. 37 and 42 (first list of fossils), and fig. 10 (bed 20), p. 38], 2.7 miles (4.3 km.) southwest of Yen- chuang, Sintai district. Shantung, China. Eoorthis hastingsensis (Walcott). Plate XCIV, figures 3, 3a-c. Orthis (Plectorthis) hastingsensis Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 263. (Described and discussed as below as a new species.) Shell transversely subeUiptical. Stu-face with numerous strong, rounded, radiating ribs increasing in number by interpolation; the ribs appear to be broader and with narrower inter- spaces on the ventral valve; concentric ridges and fine strias of gro^vth are a marked feature of the surface. A ventral valve 4 mm. in length has a width of 6 mm.; a dorsal valve 6 mm. long is 10 mm. in width. Ventral valve strongly convex, most elevated on the umbo, and without mesial fold; apex inciorved slighth^ over the delthyrium; area well defined, and divided midway b}^ a large delthyrium; it is inclined but little from the vertical. Dorsal valve slightly convex in young shells, and becoming more so as they increase in size; area low and inclined backward over the liinge line. Observations. — This species is unlike other described forms in the character of its ribs, with the exception of Eoorthis johannensis, which it resembles very closely. Matthew [1892, p. 49] describes the latter species as having a very thin shell, and it is found in the Upper Cam- brian at St. John. No interior features have been seen. Matthew [1897b, p. 170] mentions having found fragments of Protorthis or OrtTiis in the phosphate nodules at Hastings Cove, too imperfect for description. The species derives its specific name from its occurrence at Hastings Cove. Formation and locality. — Middle Cambrian: (3 1 and Zm)"^ Limestone and superjacent shale at the base of the Paradoxides zone [Matthew, lS95a, p. lOS], on Hanford Brook, St. John County; and (2s) limestone in upper part of Paradoxides zone, Hastings Cove [Matthew, 1898b, p. 38], on Kennebecasis Bay, 0.5 mile (0.8 km.) northeast of Torry- bum, on the Intercolonial Railway northeast of St. John, St. John County; all in New Brunswick. o 2 1 is the type locality. - 780 CAMBRIAN BRACHIOPODA. EOORTHIS IDDINGSI (Walcott). Plate XCI, figures 3, 3a-b. Orthisf remnicha Walcott (in part) [not N. H. Winchell], 1S99, Mon. U. S. Geol. Survey, vol. 32, pt. 2, pp. 451-452, PI. LXII, figs, la and lb (not PL LXI, figs. 3 and 3a, or PI. LXII, figs. 1, Ic, and Id). (Specimens now referred to Eoorthis iddingsi were included with E. remnicha when this description was written, two being figured, PI. LXII, figs, la and lb. The specimens represented by these two figures are redra^vn in this monograph, PI. XCII, figs. 3 and 3a, respectively. The specimens represented by PI. LXI, figs. 3 and 3a, and PL LXII, figs. 1, Ic, and Id belong with Eoorthis remnicha.) Orthis (Plectorthis) iddingsi Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 264. (Characterized as below as a new species.) General form and convexity much like that of some varieties of Eoorthis indianola. Its surface characters also approach those of the more regularly ribbed shells of the latter species. The principal difference between the two species is the less convexity, lower umbo, and lower area of E. iddingsi. The interior of the ventral valve shows a short, well-defined umbonal cavity with a strong vascular sinus on each side of it that extends well forward into the valve. The specific name is given in honor of Prof. Joseph P. Iddings. Formation and locality. — Upper Cambrian : (302c) Shaly limestone on the south side of the Gallatin Valley, Yellow- stone National Park, Wyoming; and (302d) limestone 200 yards (183 m.) north of the southwest comer sec. 18, T. 28 N., R. 113 W., Uinta County; both in Wyoming. (71) Limestone in Cold Creek Canyon, Burnet County, Texas. Eoorthis indianola (Walcott). Plate XCIV, figures It, lu, 2, 2a-h. Orthi-s {Plectorthis) indianola Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 264-265. (Described and discussed essentially as below, as a new species.) Pectorthis indianola (Walcott), Grabau and Shimee, 1907, North American Index Fossils, vol. 1, pp. 251-252. (Described.) Shell small, transverse, with the cardinal extremities roimded, angular, and in some speci- mens almost alate. Valves moderately convex, the ventral nearly twice as much so as the dorsal; the length of the hinge line varies from slightly less than the greatest width of the shell to one-fifth greater than the width of the shell across the center, in shells with extended cardinal extremities. The ventral valve may or may not have a mesial depression. In some examples the depression is broad and rounded, and in others it is shallow with stronger ribs at each margin; umbo somewhat elevated, and curving over toward the hinge line, beyond which it projects, terminating in a small, incurved beak; dorsal valve considerably less convex than the ventral; beak smaU and projecting slightly over the hinge line. The median sinus in the dorsal valve varies from a broad, shallow depression to a narrow, rather deep, furrow, that gives a bilobed appearance to the valve (PL XCIV, fig. 2f) . The strength and arrangement of the strong and minor radiating elevated ribs and striae are quite variable. On some shells the ribs or strise are very fine, of nearly equal size, and separated by grooves of about the same width (PI. XCIV, figs. 2f, 2g, and 2h). In other examples every third or more widely separated rib is stronger and elevated above a more or less broad interspace, marked by fine ribs or costse (PL XCIV, fig. 2). A few of the varia- tions in surface are illustrated. Almost nothing is known of the interior of the valves. Below the umbo in a few speci- mens there is a well-marked iDseudospondylium that is much like that of E. remnicTia. The area of the ventral valve is inclined at an angle of about 65° to the plane of the margin of the valve; it is rather low and broken midway by a strong delthyrium. The area of the dorsal valve is low and incHned well out over the hinge line. Observations. — Eoorthis indianola is almost as variable in its form and sm-face markings as E. wichitaensis, with which it is associated at a number of localities. It differs from the latter in its bilobed dorsal valve, more strongly incurved umbo and apex of the ventral valve, and BILLINGSELLID^. 781 the general appearance of convexity and rotundity of the ventral valve. This may be seen by comparing the shells marked W=E. wicJiitaensis with those marked X = £". indianola in Plate XCIV, figure lu, wliich represents a fragment of limestone in wliich the two species are associated. When the specimens of the two species are imperfect or the young shells of E. vncUtaensis occur in association with the shells of E. indianola it is difficult to determme positively to which species they belong. The specific name is derived from Indian Territory (now Oklahoma), in which the type specimen was found. Formation and locality. — Upper Cambrian: (369) Sandstones at the base of the Elvins formation, in the eastern limits of the town of Flat River, St. Francois- County; and (369b) limestone near Potosi, Washington County; both in Missouri. (9t) About 170 feet (52 m.) above the porphyry contact in the limestones of the Reagan sandstone ; and (9u) about 195 feet (59.4 m.) above the porphyry contact in the limestones of the Reagan sandstone; both in the SE. | NE. i sec. 2, T. 4 N., R. 13 W., about 15 miles (24.2 km.) northwest of Fort Sill, Comanche County, Oklahoma. (9w) About 100 feet (30.5 m.) below the Arbuckle limestone, in the limestones of the Reagan sandstone, SW. J eec. 17, T. 4 N., R. 12 W., about 11 miles (17.6 km.) northwest of Fort Sill, Comanche County, Oklahoma. (12k) Limestones of the Reagan sandstone {in the section 7 miles {11.2 hm.) north of Springer this horizon is about 225 feet (69 m.) above the porphyry contact and 55 feet {17 m.) below the Arbuckle limestone), on the west side of Honey Creek, near the southeast corner of sec. 35, T. 1 S., R. 1 E., Ardmore quadrangle { U. S. Geol. Survey), Carter County; (12n) limestones of the Reagan sandstone (in the section 7 miles (11.2 km.) north of Springer this horizon is about 240 feet (73 m.) above the porphjrry contact and 40 feet (12 m.) below the Arbuckle limestone), NW. J sec. 1, T. 2 S., R. 1 E., Ardmore quadrangle (U. S. Geol. Survey), Carter County; and (12p) about 225 feet (69 m.) above the igneous rocks in the limestones of the Reagan sandstone, at the northwest extremity of the Arbuckle Mountains, about 4 miles (6.4 km.) east of Homer, Carter County; all in Oklahoma. (14b) Limestone on Cold Creek at north end of gorge opposite the north end of Sponge Mountain, 2 miles (3.2 km.) south of the San Saba County line, in Llano County; and (71) limestone in Cold Creek Canyon, Burnet County; all in Texas. Specimens that are doubtfully referred to this species occur at the following locahty: Upper Cambrian: (68) Limestone on Packsaddle Mountain, Llano County, Texas. EOOETHIS .TOHANNENSIS (Matthcw). Plate XCVII, figures 10, 10a. Orthidna{f) johannensis Matthew, 1892, Trans. Roy. Soc. Canada for 1891, 1st ser., vol. 9, sec. 4,- No. 5, pp. 49-50, PI. XII, figs. 13a-c. (Described and discussed as a new species; see below for copy. The specimens repre- sented by figs. 13a-c are redrawn in this monograph, PL XCVII, figs. 10 and 10a, respectively.) Orihis (Plectorthis) johannensis (Matthew), Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 265-266. (Original description copied and species discussed as below.) The original description by Matthew follows : Shell subquadrate, doubly convex, rather flat, very thin. Dorsal valve depressed at the sides and front, and having a broad, shallow median sinus. The valve is about one-quarter wider than long, and the hinge line is nearly as long as the length of the shell. Umbo slightly elevated, hinge plate weak and thin. Ventral valve depressed at the sides, and having a few median ridges running from the umbo to the front of the shell. This valve is somewhat geniculated at two-fifths of its length from the umbo, and from the bend faintly raised ridges diverge to the anterior angles of the shell ; behind the geniculation the surface of the shell is marked by faLat undulations similar to those of Slrophomena rhomhoidalis. The umbo is not prominent, but the back of the valve is regularly curved and the area rather low. Closely set strife radiating from the umbo and faint concentric striae mark the shell. Length of the ventral valve, 9 mm. ; width, 10 mm. Length of dorsal, 8 mm.; width, 10 mm. This species has a low umbo for an Orthisina, and in its form recalls the genus Strophomena, as also do the con- centric undulations that are found on the back of the ventral valve. The dorsal valve, however, is convex, and the area of this and the ventral valve too high for a Strophomena. It does not appear to agree with any described species of Orthisina. It resembles 0. orientalis White somewhat in form, but is not so long nor so wide at the hinge. From O. pepina Hall it differs in its lower umbo and area, shorter hinge, and smoother surface. It approaches more closely to the form from the Potsdam sandstone of the West, figured by Hall [1863, PI. VI, fig. 22], but not named, except as "Strophomena or Strophodonta." Doctor Matthew very kindly sent me the types of tliis species. There is little that can be added to his very complete description, but I had two enlarged drawings made to illustrate 782 CMCBRIAN BRACHIOPODA. the character of the surface more fully than the illustrations given oy Matthew [1892, PL XII, figs. 13a-c]. As far as known, the characters of the shell are those of the group of species referred to Eoorthis. Formation and locaxity. — Upper Cambrian : (308b [ilatthew, 1892, p. 49]) Limestone lentiles in black shales of Division C3a of Matthew's section, Germaine Street, St. John, St. John County, New Brunswick. EOOKTHIS KATSEEI (Walcott). Plate XCVII, figures 6, 6a-b. Orthis (Plectorthis) kayseri Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28. p. 266. (Characterized as below as a new species.) Tliis is a larger shell than EoortMs Unnarssoni (Kayser), with which it is associated. Its surface is marked by numerous fine radiating striae, four or five in a distance of 1 milHmeter, and the inner laj-ers of the shell appear to be minutely punctate. The ventral valve is more convex than the dorsal, the latter bemg nearly flat in young shells. Notliing is known of the interior, except one cast of the pseudospondyhum of the dorsal valve, which is larger in proportion than that of E. Unnarssoni. The largest ventral valve has a length of 14 mm.; width, 20 mm. Tliis species belongs in the group of Eoorthis represented by E. desmopleura (Meek) and E. Unnarssoni (Kayser). The specific name was given in honor of Dr. E. Kayser. Formation and locality. — Upper Cambrian: (C64) Upper limestone member of the Kiulung group [Blackwelder, 1907a, pp. 37 and 42 {first liit of fossils), and fig. 10 (bed 20), p. SS], 2.7 miles {4.3 km.) soiithivest of Yenchuang, Sintai district. Shantung; (C68) upper part of the Chaumitien limestone [Blackwelder, 1907a, p. 36 (part of third list of fossQs)], at Chaumitien, Changhia district. Shantung; and (C74) a dense blue dolomitic limestone at the top of the Kichou limestones [lA'illis and Blackwelder, 1907, pp. 139 and 145 (5th list of fossils)], 4 miles (6.4 km.) east of Fanglanchon, Shansi; all in China. Eoorthis kichouensis (Walcott). Plate LXXXIX, figm-e 5. Orthis {Plectbrthis) kichouensis Walcott, 1906, Proc. U. S. Nat. Mus., vol. 30, p. 570. (Described as below as a new species.) This species is represented by one specimen of the dorsal valve. The outline of the shell is transversely rounded subquadrilateral; length, 9 mm.; Avidth, 13 mm.; the highest point above the plane of the margin is about 3 mm. ; the shallow median sinus, wliich begins at the umbo above the hinge line, gradually widens toward the front margin; the umbo curves over beyond the hinge hne and then under to the beak, which apparently is at or a httle over the upper edge of a very narrow area. Surface marked by numerous radiating, rounded ribs, with narrow interspaces, 7 ribs in a distance of 45 mm.; a few bifurcations of the ribs occur at irregular intervals between the apex and the margins. There are no traces of concentric striae; if on the shell originally, they have been removed by the wearing off of the outer surface. Ohservations. — This species is distinguished from all other species by the strong, incurved umbo and rounded ribs -with narrow interspaces. The specific name was derived from the Kichou formation, in wliich the species occurs. Formation and locality. — Middle Cambrian : (C75) Limestone near the base of Kichou formation [Willis and Blackwelder, 1907, p. 143], 4.5 miles (7.2 km.) south of Wutaihien, Shansi, China. Eoorthis linnarssoni (Kayser). Plate XCVII, figures 5 and 5a. Orthis linnarssoni Kayser, 1883, Thina, bj' Richthofen, vol. 4, p. 34, PI. Ill, fig. 1. (Described and discussed in German as a new species, see p. 783 for translation. Fig. 1 is reproduced in this monograph, PL XCVII, fig. 5a.) BILLINGSELLID^. 783 Orthis (Plectorthis) linnarssoni (Kayser), Walcott, 1905, Proc. TJ. S. Nat. Mus., vol. 28, p. 266. (Original description copied and species discussed as below.) The original description by Kayser follows: Shell semielliptical in outline, broader than long, with hinge edge straight, corresponding to the greatest breadth of the shell. Large (ventral) valve moderately convex. Small (dorsal) valve slightly arched, with a sinus which devel- ops at the umbo and grows quite broad and deep toward the edge. Umbo of ventral valve small, area very low. Surface of shell covered with rather sharp ribs, exceedingly variable in strength, separated by narrow furrows. By reason of repeated splitting, which begins close to the umbo, the ribs appear more like bundles of ribs. On the matrix these bundles appear as broad, obtuse-angled folds, which, owing to repeated marginal splitting in even a higher degree than on the shell itself, appear as bundles of ribs of very unlike strength. '\^1ien the surface is well preserved, a delicate concentric growth striation is perceptible. Kayser [1883, p. 35] compares this shell with "Orthis McJcsi" Salter and "0. exporrecta" Linnarsson, on account of the surface characters. It does not appear to be very closely related to either species, but it is in many respects allied to Eoorthis desmopleura (Meek) and E. wichitaensis (Walcott) . The specific name is given in honor of Dr. J. G. O. Linnarsson. Formation and locality. — Upper Cambrian: (C64) Upper limestone member of the Kiulung group [Black- welder, 1907a, pp. 37 and 42 (first list of fossils), and fig. 10 (bed 20), p. 38], 2.7 miles (4.3 km.) southwest of Yenchuang, Sintai district; and (C67) stream gravels used in making the railroad grade 0.33 mile (0.5 km.) west of the west city gate at Tsinan; both in Shantung, China. (332a) [Kayser, 1883, p. 34] Talirig, Liaotung, China. Eoorthis newberryi Walcott. Text figures 69A-D. Eoorthis newberryi Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, p. 105, PI. X, figs. 6 and 6a. (Described and discussed as below as a new species. Figs. 6 and 6a are copied in this monograph as figs. 69B and 69D.) Shell transversely subelliptical, with the cardinal extremities obtuseh^ angular; valves moderately convex, wdth the hinge line a little shorter than the greatest width of the valves. The only ventral valve in the collection show- ing a mesial fold (fig. 69A) is a small exfoli- ated shell that is somewhat doubtfully referred to the species. Two large valves, one of which is illustrated by figure 69B, have the posterior margin extended beyond the hinge line, Avith a short incurved beak; a broad, shallow median sinus begins in front of the umbo and AAddens to nearly one-third of the width of the valve at the frontal margin. On a shell 5 mm. in length the sinus is very shallow; area un- known. The dorsal valve is almost uniformly convex and without a mesial sinus or fold ; the front margin arches upward a little to provide for the extension of the margin of the ventral valve caused by its broad median sinus; beak minute and marginal; area unlaiown. Surface marked by concentric lines and ridges of growth and small, rounded, radiating ribs, with two or three smaller ribs between each two larger ridges. The shell structure is fibrous and impunctate as far as can be de- ^ D Figure 69. — Eoorthis newienyi Walcott. A, Partly exfoliated ventral valve (U. S, Nat. Mus. Cat. No. 52350a). B, Ventral valve, the type specimen, preserving some of the surface characters (U. S. Nat. Mus. Cat. No. 52350b). C, Small exfoliated ventral valve (U. S. Nat. Mus. Cat. No. 52350c)'. D, Partly exfoliated dorsal valve (U. S. Nat. Mus. Cat. No. 52350d). The specimens represented are from Locality 54c, Upper Cambrian limestone of the St. Charles formation, in Blacksmith Fork Canyon, east of Hyrum, Cache County, Utah. Figures 69B and 69D are copied from Walcott [1908d, PI. X, figs. 6 and 6a]. length of 14 termined from the material available for study. The largest ventral valve has mm.; width, IS mm. A dorsal valve 15 mm. in length has a width of 18 mm. Observations. — In form this species resembles some species of Eoorthis remnicha (Winchell) (Pis. XCI, XCII), but in surface characters it is quite unlike any of them. 784 CAMBRIAN BRACHIOPODA. The specific name is given in honor of Dr. J. S. Newberry. Formation and locality. — Upper Cambrian: (54c) About 1,100 feet {335.3 m.) above the Middle Cambrian and 120 feet (36.6 m.) beloio the top of the Upper Cambrian in the central part of the limestones forming 1 of the St. Charles formation [Walcott, 190Sf, p. 192]; and (54d) about 1,050 feet (320 m.) above the Middle Cambrian and 175 feet (53.3 m.) below the top of the Upper Cambrian, in the lower part of the limestones forming 1 of the St. Charles formation [Wal- cott, 1908f, p. 192]; both in Blacksmith Fork Canyon, about 10 miles (16.1 km.) east of Hyrum, Cache County, Utah. EOORTHIS NEWTONENSIS (Wellcr). Plate XCVII, figures 9, 9a. Orthis neivtonensis Wellbr, 1903, Geol. Survey New Jersey, Kept. Paleontology, vol. 3, pp. 113-114, PI. I, figs. 3-5. (Described and discussed as a new species.) Orthis {Plectorthis) newtonensis (Weller), Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 267. (Described and dis- cussed as below.) Tliis Httle shell occurs in the form of casts in a sandstone that is too coarse to preserve the details of the outer surface. The cast of the interior shows fine, simple, radiating ribs that increase by interpolation and that are coarser on the ventral than on the dorsal valve. Ventral valve shghtly flattened at the front; dorsal valve with a broad mesial sinus. The sheU appears to have been tliin. The cast of the pseudospondyUum of the ventral valve shows it to have been clearly defhied; the area is low and not sharply defined from the curve of the cardinal margin; it is nearly vertical to the plane of the margin of the valve. The cast of the area beneath the umbo in the dorsal valve is more triangular and less transverse than usual; imfortunately the material is too imperfect to determine any details. Observations. — Tliis species is the eastern representative in the Upper Cambrian of Eoorthis indianola (Walcott) and E. iddingsi (Walcott). As far as can be determined by the material available for comparison it is closely related to those species but it is not probable that they are specifically identical. The specific name is derived from Newton, New Jersey. Formation and locality.— Upper Cambrian: (lie) Hardyston quartzite [Weller, 1900, pp. 10 and 12], O'Don- nell and McManniman's quarry, Newton, Sussex County, New Jersey. Eoorthis pagoda (Walcott). Plate XCVII, figures 12, 12a-d. Orthis (Plectorthis) pagoda Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 267-268. (Described and discussed as below as a new species.) SheU transverse, subsemicircular; a ventral valve 11 mm. in length has a width of 15 mm., and a dorsal valve 8 mm. in length has a width of 13 mm.; liinge line a little shorter than the greatest width of the shell; cardinal angles vary from 75° to 111°; valves moderately convex. Cardinal area narrow in both valves and inclined backward from the hinge line. Surface marked by equidistant, narrow, low ribs, 3 in a space of 2 mm. near the front margin of a shell 10 mm. long, with fine, radiating strise between them; the radiatmg ribs and striae are crossed by fine, concentric strise, and lines of growth. Ventral valve with a strong, somewhat angular, median fold rising from a well-defined depression on each side of it, or it might be designated as a very strong rib rising above the general surface of the valve from a broad, median depression; the lateral slopes are gently convex. Dorsal valve with a strong, angular, median depression, begmning at the posterior margin and graduaUy widening to the front; the sides of the depression rise above the general stirface of the valve, and form with the outer slope a well-defined low ridge on each side that extends a Uttle forward on the front margin to fit into the depressions on each side of the median fold of the ventral valve. The interior of a small dorsal valve has a broad, strong ridge corresponding to the depres- sion on the exterior surface ; a mam vascular sinus starts on each side of the base of the median ridge and arches outward and then forward about a depressed oval space on each side of the BILLINGSELLID.E. > 785 ridge; lateral branches extend from the main sinus toward the sides; the impressions of the anterior and posterior adductor muscle scars occm- on the slopes of the median ridge and the oval depressions; somewhat obscure radiating lines mark the anterior portions of the surface. Observations. — Tliis shell is distmguished by its strongly marked median ridge on the ventral valve and sinus on the dorsal valve. In general form and surface markings it is not unlike EoortUs desmopleura (Meek) and E. mchitaensis (Walcott). The specific name is derived from Pagoda Hill, the type locahty. Formation AND LOCALITY. — Upper Cambrian: (C56) Lower part of Chaumitien limestone, at Pagoda Hill [Black- welder, 1907a, p. 42 (part of last list of fossils)], 1 mile (1.6 km.) west of Tsinan; and (C54) lower part of the Chaumitien limestone [Blackwelder, 1907a, p. 42 (part of last list of fossils)], 0.66 mile (1.1 km.) west of Tsinan; both in Shantung, China. EooRTHis PAPiAS (Walcott). Plate XCI, figure 4. Orthis (Plectorthis) papias Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 268. (Characterized as below as a new species.) This species is foimded to receive a form represented by two small dorsal valves from the Paradoxides zone of Newfoundland. They are moderately convex, -with a low area divided by a broad delthyrium; surface marked by numerous, rounded, depressed ribs, crossed by con- centric strife and ridges of growth. Length of shell, 4 mm. ; width, 5 mm. Formation and locality. — Middle Cambrian: (61) Shales near the top of No. 6 of the Manuels Brook section [Walcott, 1891b, p. 261], east side of Manuels Brook, Conception Bay, Newfoundland. EooETHis PRiMORDiALis (de Vemeuil and Barrande). Plate XCVII, figures 1, la-d. Orthis priTnordialis de Verneuil and Barrande, 1860, Bull. Soc. g6ol. France, 2d ser., vol. 17, pp. 532-533, PI. VIII, figs. 6, 6a-d. (Described and discussed in French, as a new species; see below for translation. Figs. 6, 6a-d are reproduced in this monograph, PI. XCVII, figs. 1, la-d, respectively.) Orthis primordialis de Verneuil and Barrande, Mallada, 1875, Bol. Com. Mapa Geologico Espana, tome 2, p. 31. (Men- tioned in Spanish.) The original description by de Vemetdl and Barrande follows: Shell transverse, rounded on the sides, wider than long. Hinge ridge does not extend to lateral extremities and measures hardly more than three-fourths of the total breadth of the shell. The two valves are of about the same thick- ness. The ventral valve a is pro%aded with an area hardly higher than that of the opposite valve, but it is distinguished from it by a sinus which is almost as deep as that of the Spirifers, and which in front forms a very pronounced and more or less sharp fold. Surface ornamented with striae, very dichotomous on the sides and almost simple in the sinus; at a distance of 5 mm. from the beak, 7 striae are counted in a space of 5 mm. Breadth, 16 mm. ; length, 12 mm. ; thickness, 7 mm. By its deep sinus, this species is distinguished from most of its congeners and establishes a sort of passage between the genera Orthis and Spirifer; however, the pronounced area observed on each of the two valves is a characteristic which links it with the former rather than with the latter genus. Orthis species provided with sinuses are rather rare; the principal ones are 0. sinuata Hall and 0. striatula Schl., which for that matter have no other analogy with our species. It might perhaps be assimilated to 0. lynx, which also has two areas equally developed, but the latter species will always be recognized by the small number and nondichotomous nature of its folds. Ohservations. — This shell is more strongly developed in the sinus of the ventral valve and the fold of the dorsal valve than any other species of Cambrian Eoorthis, with the possible excep- tion of E. indianola CWalcott) of the Middle and Upper Cambrian of the Wichita Mountains of the United States. The latter has a higher area on the ventral valve and the sinus is often shallow, while the fold is usually absent. Formation and locality. — Middle Cambrian: (350 [de Vemeuil and Barrande, 1860, p. 538]) Red limestone of the Paradoxides zone, near Adrados, north of Sabero and Bofiar, Cantabrian Mountains, Province of Leon, north- western Spain. a Following here tbe example ot Owen and Davidson, we call ventral valve the larger of the two, the one which is provided with a large area, and which formerly was called dorsal valve. 62667°— VOL 51, pt 1—12 50 786 CAMBRIAN BRACHIOPODA. EooRTHis REMNiCHA (N. H. Winchell). Text figure 7, page 299; Plate XCI, figures 1, la-s; Plate XCII, figures 2, 2a-d, 3, 3a-e. Orthis remnicha N. H. Winchell, 1886, Fourteenth Ann. Kept. Geol. and Nat. Hist. Survey Minnesota, pp. 317-318, PI. II, fig. 7. (Described and discussed as a new species.) OrtMsf remnicha Winchell, Walcott (in part), 1899, Mon. U. S. Geol. Survey, vol. 32, pt. 2, pp. 451^52, PL LXI, figs. 3 and 3a; PI. LXII, figs. 1, Ic-d (not figs, la and lb). (Described and discussed essentially as below, The specimens represented by PI. LXI, figs. 3 and 3a, and PI. LXII, figs. 1, Ic, and Id, are redrawn in this mono- graph, PL XCII, figs. 2b, 2a, 2, 2d, and 2c, respectively. The specimens represented by PL LXII, figs, la and lb, are now referred to Eoorthis iddingsi.) Onthis (Plectorthis) remnicha (Winchell), Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 268-269. (Described and discussed essentially as below.) Plectorthis remnicha (Winchell), Grabau and Shimek, 1907, North American Index Fossils, vol. 1, p. 252. (Described.) Shell of medium size, usually slightly transverse, with an oblong, oval outline for the ventral valve, and a subquadrate .to semicircular outline for' the dorsal valve. Valves moder- ately convex, with an almost straight hinge line that varies in length from nearly the greatest width of the shell to two-thirds the greatest width; cardinal angles varying from 90° or less in the extreme forms, with extremities somewhat angular, to the other extreme, where they are very obtuse and have the appearance of being almost rounded, their angle being not less than 120°. Cardinal area narrow but well developed on each valve, and divided by a rather large delthyrium. The ventral valve has in some specimens a shallow mesial depression, and in some examples it is flattened toward the cardinal angles; beak small and curving down toward the hinge line, beyond which it projects slightly. Dorsal valve slightly less convex than the ventral; beak small, scarcely projecting beyond the hinge line. Siirface marked by bifurcating, radiating costse, that vary in number on shells of similar size from 16 in the space of 5 mm. to 3 in the same space; this variation is shown in the speci- mens from Texas, Wisconsin, and Wyoming. As the shell grew the ribs increased in number by interpolation and by bifurcation from the sides of the larger ribs. In well-preserved specimens very fine, radiating, raised striae occur both on the costse and on the intervening depressions (PI. XCII, fig. 2c). These are shown on the casts of the shells from the "St. Croix sandstone of Winfield, Wisconsin, and on the larger shells from the limestones of Oklahoma and the Yellowstone National Park. A very perfectly preserved fragment of the outer shell covering the umbo and apex of a ventral valve from the limestone of the Reagan sandstone, Oklahoma has sharp ribs of varying size extending to the worn apex; the ribs are crossed by very fina, threadlike striae and a few stronger lines of growth. The interior of the ventral valve shows a slightly raised tripartite pseudospondylium beneath the umbo, which is the only trace of interior markings of this valve observed. The interior of the dorsal valve has a slightly elevated area upon which occurs a narrow, short median septum; the crural plates are also well shown. In casts of the interior of shells from the "St. CroLX sandstone" of Wisconsin, the dental lamellae of the ventral valve are finely shown, and in the dorsal valve the median septimi and crural plates. Observations. — The shell is one of the most variable that occurs in the Cambrian fauna. Its range of variation in all of the widely separated localities in which it occurs is such that one would scarcely hesitate, if in possession only of the extremes, to identify two well-marked species. The variation is not only in the radiating costse, but also in the general form of the shell. This variation is expressed in three varieties that receive names, and others might be designated if more minute variations were given consideration. There does not appear to be any system governing the number or size of the radiating ribs ; the variation on adult shells is equally great with that between young shells 3 to 4 mm. long and adults. A series from Winfield, Wisconsin, representing Eoorthis remnicha winfieldensis, is uniform in radial ribs and form from yoxmg shells 3 mm. long to the largest adults 23 mm. long, and there are also shells that serve to unite the numerously and uniformly ribbed speci- mens with the more variable Eoorthis remnicha. BILLINGSELLID^. ' 787 Some of the shells referred to E. remnicJia (PI. XCI, figs. 1,1a, and le) suggest PlatystropTiia m their form and radiating ribs. Formation and locality. — TTpper Cambrian : (80a) "St. Croix sandstone," 4 miles (6.4 km.) north of Reedsburg, Sauk County; (328c() "St. Croix sandstone" in quarry at Ableman, Sauk County; and (97a) "St. Croix sandstone," near Winfield, Jefferson County; all in Wisconsin. (86a) "St. Croix sandstone" near Red Wing, Goodhue County, Minnesotafi (153a and 154) Limestone on west side of Dry Creek, near the mouth of Pass Creek, about 5 miles (8 km.) north of Hillsdale, Threeforks quadrangle (U. S. Geol. Sm-vey), Gallatin County; (302n) limestone on the south side of the Gallatin Valley; Gallatin County; and (4r) just above the Middle Cambrian in the limestones of the Gallatin formation of Peale [1893, PI. IV], on ridge 8 miles (12.8 km.) east of Yellowstone River, and 3 miles (4.8 km.) north-northeast of Mount Delano, Livingston quadrangle (U. S. Geol. Survey), Park County; both in Montana. (168) Limestone on north side of Tepee Creek, beside the road fi-om Sheridan to Dome Lake, Bighorn Mountains, Sheridan County, Wyoming. (12k) Limestones of the Reagan sandstone (in the section 7 miles (11.2 km.) north of Springer this horizon is about 225 feet (69 m.) above the porphyry contact and 55 feet (17 m.) below the Arbuckle limestone) on the west side of Honey Creek, near the southeast corner of sec. 35, T. 1 S., R. 1 E., Ardmore quadrangle (U. S. Geol. Survey), Carter County; (12n) limestones of the Reagan sandstone (in the section 7 miles (11.2 km.) north of Springer this horizon is about 240 feet (73 m.) above the porphyry contact and 40 feet (12 m.) below the Arbuckle limestone),. NW. \ sec. 1, T. 2 S., R. 1 E., Ardmore quadrangle (U. S. Geol. Survey), Carter County; and (12p) about 225 feet (69 m.) above the igneous rocks in the limestones of the Reagan sandstone, at the northwest extremity of the Arbuckle Moun- tains, about 4 miles (6.4 km.) east of Homer, Carter County; all in Oklahoma. Middle Cambrian: (302b) Limestone near Crowfoot Ridge, Gallatin quadrangle (U. S. Geol. Survey), Yellowstone National Park, Wyoming. Specimens that are somewhat doubtfully referred to this species occur at the following locality : Middle Cambrian: (3x) About 2,200 feet (670.6 m.) above the Lower Cambrian and 2,200 feet (670.6 m.) below the Upper Cambrian in the limestone forming Id of the Marjum limestone [W^alcott, 190Sf, p. 180], 2.5 miles (4 km.) east of Antelope Springs, in lidge east of ^Mieeler Amphitheater fWalcott, 1908f, Pis. XIII and XV], House Range, Millard County, Utah. EOORTHIS REMNICHA SULCATA (Walcott). Plate XCII, figures 1, la-c. Orthis {Plectorthis) remnicha sulcata Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 269. (Characterized somewhat as below as a new variety.) This variety is founded on the strongly sulcate dorsal valve. The ventral valve shows only a shght flattening of the median portion. Finkelnhurgia osceola (PI. XCIII) has a mesial fold on the dorsal valve, but it is not so sharp. Formation and locality. — Upper Cambrian: (80a) "St. Croix sandstone," 4 miles (6.4 km.) north of Reedshurg, Sauk County; and (97a)-"St. Croix sandstone" near Winfield, Jefferson County; both in Wisconsin. (339d) "St. Croix sandstone " at Taylors Falls, Chisago County ; and (97x) "St. Croix sandstone " at Reads Landing, foot of Lake Pepin, Wabasha County; both in Minnesota. ' EOORTHIS REMNICHA TEXANA (Walcott). Plate XCII, figures 4, 4a-g. Orthis (Plectorthis) remnicha texana Walcott, 1905, Proc. U. S. Nat. Miis., vol. 28, p. 270. (Characterized as below as a new variety.) The rounded, subquadrate form and the arrangement of the radiating cost^ serve to differentiate this variety. The costse vary considerably on different shells, but the tendency of the larger number is toward the surface represented by Plate XCII, figures 4c-g. Fine radiating striae, similar to those represented by Plate XCII, figure 2c, of Eoorthis remniclm occur on the ribs and interspaces. Formation and locality. — Upper Cambrian : (12m) Arbuckle limestone (in the section 7 miles (11.2 km.) north of Springer this horizon is about 30 feet (9.1 m.) above the Reagan sandstone), NE. J sec. 2, T. 2-S., R. 1 E. ; and (12n) limestones of the Reagan sandstone (in the section 7 miles (11,2 km.) north of Springer this horizon is about 240 feet oN. H. Winehell [1886, p. 317] gives the type locality as "St. Croix sandstone" in sewer excavation at the corner of Brush and Main streets, Red Wing, Minnesota. 788 ' CAMBRIAN BRACIilOPODA. (73 ni.) nbove the porphjTy contact and 40 feet (12 m.) below the Arbuckle limestone), NW. J sec. 1, T. 2 S., R. 1 E.; both in the Ardmore quadrangle (U. S. Geol. Survey), Carter County, Oklahoma. (153a) Limestone in ra\dne on west side of Dry Creek, near the mouth of Pass Creek, about 5 miles (8.1 km.) north of Hillsdale, Thi-eeforks quadrangle (U. S. Geol. Survey), Gallatin County, Montana. (14b) Limestone on Cold Creek at north end of gorge opposite the north end of Sponge Mountain, 2 miles (3.2 km.) south of the San Saba County line, in Llano County; (68) interbedded sandstone and limestone, Packsaddle Mountain, Llano County; and (71) limestone in Cold Creek Canyon, Burnet Countij; all in Texas. Specimens that are somewhat doubtfully referred to this variety occur at the following locaHties : Upper Cambrian : (lid) Arenaceous limestone about 2 miles (3.2 km.) north of Montana, in sec. 22, T. 35 N., R. 1 E., Iron County; and (11 1) arenaceous limestone of the Elvins formation, 50 feet (15.2 m.) above the "Edgewise beds," St. Francois County; both in Missouri. EOORTHIS REMNICHA WINFIELDENSIS (Walcott)'. Plate XCI, figures 2, 2a-e. Orihis (Plectorthis) remnicha vnnfieldensis Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 270. (Characterized as below as a new variety.) • This variety is characterized by having finer and more uniform costae than any of the shells referred to Eoorthis remnicha (N. H.Winchell). The costse increase by interpolation rather than bifurcation in the true sense of the word. The shorter costaj begin as very narrow, sharp ridges, merging into the sides of the larger costae below the summit of the latter, or they may arise entirely on the interspaces between the costse. The pseudospondylium is less strongly developed than in E. remnicha. The young shells are usually narrower at the hinge line than the adult; but this feature is sometimes present in large shells (PI. XCI, fig. 2c). The varietal name is derived from Winfield, Wisconsin. Formation and locality.— Tipper Cambrian: (97a) "St. Croix sandstone," near Winfield, Jefferson County; and (99a) "St. Croix sandstone" near Pilot Knob, Adams County; both in Wisconsin. A specimen which is somewhat doubtfully referred to this variety occurs in the following locahty : Tipper Cambrian: (83) "St. Croix sandstone" at Trempealeau, Trempealeau County, Wisconsin. Eoorthis saltensis (Kayser). Plate XCVII, figure 11. Orthis saltensis Kayser, 1876, Beitrage ziu- Geologie und Paleontologie der argentinischen Republik, vol. 2, Pale- ontologischen TheQ; Abth. 1, p. 8, PI. I, figs. 15, 16. (Described and discussed in German as a new species; see below for translation. Figs. 15 and 16 are reproduced in this monograph, PL XCVII, figs. 11' and 11, respec- tively.) Orthis saltensis? Kayser, 1897, Zeitschr. Deutsch. geol. Gesell. for 1897, Bd. 49, Heft 2, No. 2, p. 280. (Mentioned in German from new localities.) Orthis {Plectorthis) saltensis (Kayser), Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 271. (Characterized.) The original description by Kayser follows : Shell nearly circular in outline, with straight hinge edge, which is about equal to three-fourths of the greatest breadth of the shell, measured approximately across the middle. . Ventral valve moderately and uniformly arched, with a faint keel rising in the middle. Beak short, slightly curved. Dorsal valve slightly arched, with a median depression which is flat but becomes rather broad, starting at the umbo. The surface of both valves is covered with fine but plainly marked ribs, united into bundles, the lateral ones- bending somewhat outward. In the sandstones in the province of Salta this species fills whole beds. At the town of Salta it occurs alone. At the Nevado de Castillo it is accompanied by Lingula. At both localities it occurs as impressions and casts, and as white, well-preserved shell, peeling off in flakes. Finally it also occurs, associated with trilobites, Eyolithes, and other Orthis species, at Tilcuya in the province of Jujuy, but there it is without calcareous shell. I know only one primordial Orthis with which this fine species might be compared, namely Orthis menapix Hicks [cf. Davidson, 1869, PL XXXIII, figs. 8-12], from, the English Arenig group. In this, however, the ribs show less tendency to arrange themselves in bundles, the sinus is narrower, and the ventral valve is much more strongly keeled. Kayser's description and figures [1876, p. 8, PI. I, figs. 15-16] lead me to refer this species to the genus Eoorthis. The general form of the valves, the casts of the interior of the ventral BILLINGSELLID^. 789 valve with the strong umbonal cavity, and the radiating ribs increasing in number by inter- polation, appear to sustain the reference. The species derives its name from its occurrence near Salta. Formation and locality. — XTpper Cambrian : (389 [Kayser, 1876, p. 8]) Sandstone at Salta, Province of Salta; (389a [Kayser, 1876, p. 8]) sandstone at Nevado de Castillo, Province of Salta; (389d [Kayser, 1897, p. 280]) at Iruya, Province of Salta; (389c [Kayser, 1897, p. 280]) in conglomeratic sandstone at Ojo de Agua, Province of Santiago del Est; and (389b [Kayser, 1876, p. 8]) sandstone at Tilcuya, Province of Jujuy; all in Argentina, South America. Kayser [1876, p. 9, PI. I, fig. 13] also describes and illustrates the dorsal valve of a shell that he refers to X)rtliis sp. It suggests Orusia lenticularis. EooRTHis TATEi (Etheridge). Plate XCVII, figures 15 and 15a. Orthis (?)tatei Etheridge, jr., 1905, Trans. Roy. Soc. South Australia, vol. 29, p. 249, PI. XXV, figs. 7 and 8. (Described as below, and discussed as a new species. The specimens represented by figs. 7 and 8 are redrawn in this monograph, PI. XCVII, figs. 15 and 15a, respectively.) The original description by Etheridge follows: Pedicle valve, dorsal margin comparatively straight; ventral and lateral margins rounded, the former nonmar- ginate; umbo small, depressed; surface in the median line moderately convex, the wings rather flattened; sculpture consisting of numerous, thick, sometimes bifurcating radiating costse, which die out, or are only faintly perceptible on the wings or toward the lateral margins of the valves, the surface on these portions being also crossed by very fine concentric lines; by the prominence of two or three costfe on each side of the middle, a flattened space, taking the place of a sulcus, is marked off. This species appears to belong to the group of Eoorthis represented by E. remnicha (N. H. Winchell). The specific name is given in honor of Mr. Ralph Tate. Formation and locality. — Middle? Cambrian: (315b [Etheridge, 1905, p. 249*]) Limestone at Wuxialpa, Eoorthis thyone Walcott. Text figures 70A-C. Nisusia rara W-4.lcott (in part), 1908, Smithsonian Misc. Coll., vol. 53, No. 3, p. 97, PI. IX, fig. 13 (not fig. 13a, which represents a specimen of Nisusia rara). (No text reference. Fig. 13, which is reproduced in this monograph as fig. 70A, was inserted on PL IX of this reference by mistake. All of the figures representing the two species (Nisusia rara and Eoorthis thyone) happened to be grouped on the same preliminary plate and when two figures were chosen to represent Nisusia rara in the paper referred to, one of the figures repre- senting Eoorthis thyone was acci- dentally included.) Eoorthis thyone Walcott, 1908, idem, pp. 105-106, PL X, figs. 7 and 7a. (De- scribed and discussed as below as a new species. Figs. 7 and 7a are copied in this monograph as figs. 70B and 70C, respectively.) In outline and size this species resembles Eoorthis vncMtaensis (Walcott) (PI. XCIV, figs. 1, la-n), but in its sharp, uniform, radiating ribs it differs from that and other species having a somewhat similar outline. The ribs radiate from the beak and increase in number by inter- polation of new ribs at irregular distances fromi the beak. Nothing is known of the area of either valve. A cast of the interior of a dorsal valve shows rather large muscle scars. A large ventral valve has a length of 8 mm. ; width, 9 mm. ; substance of shell unknown. Figure 70. — EoorthU thyone Walcott. A, Natural cast of a ventral valve, the type speci- men, showing cast of a pseudospondylium (U. S. Nat. Mus. Cat. No. 5237S). B, Natural cast of a dorsal valve (U. -S. Nat. Mus. Cat. No. 52377a). C, Cast of interior of dorsal valve (U. S. Nat. Mus. Cat. No. 523771)). The specimens represented are from Middle Cambrian Marjum limestone, 2.5 miles (4 km.) east of Antelope Springs, in the ridge east of AVheeler Amphitheater, House Range, Millard County, Utah (fig. 70.-V from Locality 3x, and figs. 70B and 70C from Locality llq). Figure 70A was published [Walcott, 1908d, PI. IX, fig. 13] as representing the ventral valve of Nisusia rara and was given Cat. No. 52295a. As explained in the note under the first reference in the synonymy this was a mistake. Figures 70B and 70C are copied from Walcott [1908d, PI. X, figs. 7 and 7a, respectively]. 790 CAMBRIAN BRACHIOPODA. Observations. — Tliis species was at first compared with Nisusia (Jamesella) nautes (Walcott) (PI. XCIII, figs. 6, 6a-b), but the surface ribs are more regular and less numerous. It also occurs 1,800 feet lugher in the stratigraphic section than N. (J.) nautes. Formation AND locality. — Middle Cambrian: (3x) About 2,200 feet (670.6 m.) above the Lower Cambrian and 2,200 feet [670.6 m.) below the Upper Cambrian, in the limestones forming id of the Marjum limestone {Walcott, lOUSf, p. ISO]; and (llq) about 2,350 feet (716.3 m.) above the Lower Cambrian, and 2,050 feet (624.8 m.) below the Upper Cambrian, in the limestones forming Ic of the Marjum limestone [Walcott, 190Sf, p. 180]; both 2.5 miles (4 km.) east of Antelope Springs, in ridge east of A^Tieeler Amphitheater [Walcott, 1908f , Pis. XIII and XV], House Eange, Millard County, Utah. EOOETHIS TULLBEEGI (Walcott). Plate XCV, figm-e 3. Or'his (Plectorthis) tullbergi Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 271. (Characterized as a new species.) Orthis (Plectorthis) tullbergi Walcott, Moberg and Segerberg, 1906, Medd. fran Lunds Geol. Faltklubb, Ser. B, No. 2 (Aftryck ur K. Fysiografiska Sallskapets Handl., N. F., Bd. 17), p. 69, PI. II, fig. 3. (Characterized in Swedish. Fig. 3, in common with the remaining figures on PI. II of Moberg and Segerberg's paper, was copied from a preliminary photograph of PI, XCV of this monograph.) The transverse outline and simple strong ribs of Eoorthis tullbergi serve to distinguish it from E. christianise (Kjerulf) and E. daunus (Walcott). Moberg and Segerberg [1906, pp. 69-70] are inclined to consider this form as identical with Eoorthis christianise. Since reading their remarks and conclusions I have studied the material representing the two forms Eoorthis christianise and E. tullbergi and have decided to leave the latter as a distinct species. There may be a complete gradation of form and surface characters between the two shells, but I do not find it in the numerous specimens before me. The specific name was given in honor of Mr. S. A. Tullberg. Formation and locality. — Passage beds between the Upper Cambrian and the Ordovician: (390) Boundary stratum between the Orthoceras limestone and the Ceratopyge limestone [Moberg and Segerberg, 1906, p. 69], at Alunbruk (alum works), southern part of Oeland Island, Sweden. Eoorthis wichitaensis (Walcott). Plate XCIV, figures 1, la-o, lu. Orthis (Plectorthis) wichitaensis Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 271-272. (Characterized essen- tially as below as a new species.) In general form and outline this shell is related to Eoorthis desmopleura (Meek) and E. revrmicha (Winchell). Its convexitj^ and differences in the radial ribbing and striation sep- arate it from the former species, and it occurs in an older geological formation. Its convexity and surface characters distinguish it from E. remnicha. The series of figures illustrating the species will enable the student to study all that is Ioiowti to me of the species. A considerable number of relatively smooth shells that occur in the collection are desig- nated as the variety Iseviusculus, but it is often difficult to separate them from the more finely ribbed specimens that are typical of the species. Formation and locality. — Lower Ordovician: (360a) Red siliceous limestone on west side of Trout Creek, below Bergen Park, 7 miles (11.2 km.) north-northwest of Manitou, El Paso County, Colorado. Tipper Cambrian: (12]) Lower part of Arbuckle limestone at Small Hill, 2 miles (3.2 km.) southwest of Signal Mountain, about 8 miles (12.8 km.) west of Fort Sill; and (9z) basal beds of the Arbuckle limestone, about 25 feet above the heavy-bedded limestone, near the middle of the west half of sec. 13, T. 4 N., R. 13 W., about 13 miles (20.8 km.) northwest of Fort Sill; both in Comanche County, Oklahoma. (Sq) About 10 feet (3 m.) above the porphyry contact and 90 feet (27.4 m.) below the Arbuckle limestone in limestones of the Beagan saiidstone, in middle of west half of sec. 2, T. 4 N., R. 13 W.; (9u) about 195 feet (59.4 m.) above the porphyry contact in the limestones of the Reagan sandstone, in SE. -J NE. J sec. 2, T. 4 N., R. 13 W.; (9s) about 85 feet (26 m.) below the Arbuckle limestone in the limestones of the Reagan sandstone, near middle of west half of sec. 13, T. 4N., R. 13 W.; all about 15 miles (24.2 km.) northwest of Fort Sill, Comanche County, Oklahoma. (12k) Limestones of the Reagan sandstone (in the section 7 miles (11.2 km.) north of Springer this horizon is about 225 feet (69 m.) above the porphyry contact and 55 feet (17 m.) below the Arbuckle limestone), on the west BILLINGSELLID^. 791 Bide of Honey Creek, near the southeast corner of sec. 35, T. 1 S., R. 1 E., Ardmore quadrangle (U. S. Geol. Survey), Carter County; (13n) limestones of the Reagan sandstone (in the section 7 miles (11.2 km.) north of Springer this horizon is about 240 feet (73 m.) above the porphyry contact and 40 feet (12 m.) below the Arbuckle limestone), NW. J sec. 1, T. 2 S., R. 1 E., Ardmore quadrangle (U. S. Geol. Survey), Carter County; and (12p) about 225 feet (69 m.) above the igneous rocks in the limestones of the Reagan sandstone, at the northwest extremity of the ArbucMe Mountains, about 4 miles {6.4 hm.) east of Homer, Carter County; all in Oklahoma. (lib) Limestone on Cold Creek at north end of gorge opposite the north end of Sponge Mountain, 2 miles (3.2 km.) south of the San Saba County line, in Llano County; (68) limestone on Packsaddle Mountain, Llano County; and (71) limestone in Cold Creek Canyon, Burnet County; all in Texas. (150a) Limestone on the east side of Dry Creek, above the mouth of Pass Creek; and (163a) limestone in raAane on west side of Dry Creek, near the mouth of Pass Creek; both about 5 miles (8 km.) north of Hillsdale, Threeforks quadrangle (LT. S. Geol. Sm'vey), Gallatin County, Montana. (151) Limestone in point overlooking Churn Canyon, on the west side of the Bridger Range, Gallatin County, Montana. (302e) Limestone near the top of the Deadwood formation, in Middle Popo Agie Canyon, near Lander, Fremont County, Wyoming, Middle Cambrian: (369a) Limestone in or just beneath the "Edgewise beds" near Elvins, 6 miles (9.6 km.) south of Bonneterre, St. Francois County, Missouri. EOOETHIS WICHITAENSIS L^VITJSCtTLtrs (Walcott). Plate XCIV, figm-es Ip-s. Orthis (Plectorthis) unchitaensis Ixviuseulus Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 272. (Characterized essentially as below as a new variety.) A variety with, small, narrow, numerous ribs is given the above name. So many grada- tions exist between it and the typical forms of E. wichitaensis (Walcott) that the figures are arranged on the plate rather to show the gradations in surface characters than to bring out this special variety. Formation and locality. — TTpper Cambrian: (12k) Limestones of the Reagan sandstone (in the section 7 miles (11.2 km.) north of Springer this horizon is about 225 feet (69 m.) above the porphyry contact and 55 feet (17 m.) below the Arbuckle limestone), on the west side of Honey Creek, near the southeast corner of sec. 35, T. 1 S., R. 1 E., Ardmore quadrangle (U. S. Geol. Survey), Carter County; (12n) limestones of the Reagan sandstone (in the section 7 miles (11.2 km.) north of Springer this horizon is about 240 feet (73 m.) above the porphyry contact and 40 feet (12 m.) below the Arbuckle limestone), NW. } sec. 1, T. 2 S., R. 1 E., Ardmore quadrangle (U. S. Geol. Survey), Carter County; and (12p) about 225 feet (69 m.) above the igneous rocks in the limestones of the Reagan sandstone, at the northwest extremity of the Arbuckle Mountains, about 4 miles (6.4 km.) east of Homer, Carter County; all in Oklahoma. (14b) Limestone at north end of gorge opposite the north end of Sponge Mountain, 2 miles (3.2 km.) south of the San Saba County line; and (68) limestone in Packsaddle Mountain; both in Llano County, Texas. EOORTHIS WIMANI (Walcott). Plate XCV, figures 4, 4a-d. » Orthis (Plectorthis) loimani Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 272. (Discussed essentially as below as a new species.) Orthis (Plectorthis) wimani Walcott, Moberg and Segerberg, 1906, Medd. fran Lunds geol. Faltklubb, Ser. B, No. 2 (Aftryck ur K. Fysiografiska Sallskapets Handl., N. F., Bd. 17), p. 70, PL II, figs. 4, 4a-d; PL III, figs. 14, 15a-b. (Discussed in Swedish. Figs. 4, 4a-d, in common with the remaining figures on PL II of Moberg and Segerberg's paper, were copied from a preliminary photograph of PL XCV of this monograph.) This shell is distinguished from Eoorthis christianise (Kjerulf) and E. daunus (Walcott) by the rounded, narrow, simple ribs and the less transverse and more rounded outline. A ventral valve discovered after the drawings were made shows a well-defined pseudospondylium, with the tripartite division as seen in E. remnicha (Winchell) (PI. XCI, fig. Ic). Two strong main vascular sinuses extend forward from the lateral divisions of the umbonal cavity nearlj^ to the front of the valve, corresponding in position to those of the dorsal valve (PI. XCV, fig. 4a) . The cast of the dorsal valve indicates the presence of rather strong crura, crural plates, dental sockets, and delthyrium. The ventral valve is rather strongly convex, and the dorsal valve about half as much so. The average size is 6 to 7 mm. in diameter, the ventral valve being about 1.5 mm. larger 792 CAMBRIAN BRACHIOPODA. than the dorsal. The hxrgest ventral valve in the material available for study has a lenj^th of 9 mm. The specific name was given in honor of Dr. Carl Wiman. FoRM.\TioN AND LOCALITY. — Passage beds between the Upper Cambrian and the Ordovician: (310j) Ceratopyge limestone at Borgholm, Oeland Island, Sweden. (8x) Limestone at Slemmestad, about 3 miles (4.8 km.) southwest of Christiania, Norway. Upper Cambrian: (390b [Moberg and Segerberg, 1906, p. 71]) Limestones of the Shumardia zone (zone 3) at Fogel- sang, 5 miles (8 km.) east of Lund, Province of Malmohus; and (390c [Moberg and Segerberg, 190G, p. 70]) Ceratopyge slate (Zone 3) at Wentlinge, on Oeland Island; both in Sweden. (323w) Black argillaceous shale of Division 3aj3, at Christiania, Norway. EooRTHis ZENO Walcott. Text figures 71A-B'. Eoorthis zeno Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, p. 106, PI. 10, fig. 8. (Discussed as below as a new species. Fig. 8 is copied in this monograph as fig. 71A.) In outline the ventral valve of this species is somewhat similar to that of some forms of Eoorthis remnicha winfieUens'ls (Walcott) (PI. XCI, fig. 2d), but it differs in having finer radiating ribs and in its smaller size. It is also much smaller than Eoorthis neviberryi Walcott, and it occurs 4,390 feet (1,-338 m.) lower in the same stratigraphic section. The character of the surface is shown by text figure 7lB', and the general form by text fig- ure 7lA. I do not know of any similar form, with such regular, fine, sharp radiating ribs, from the FiGUKE 71.— j;oorffl!s zcmo Walcott. A, A', Exfoliated ventral valve (U. S. Nat. Mus. Cat. No. 52397a). B, Fragment of dorsal valve (U. S. Nat. Mu-s. Cat. No. 62397ti). B', Enlargement of portion ol surface ol B (X 10). The specimens represented are from Locality 54o, Middle Cambrian Ute limestone in Blacksmith Fork, aljout 10 miles (16.1 km.) east of Hyrum, Cache County, Utah. Figure 71A is copied from Walcott [IQOSd, PI. X, fig. S]. It is the type specimen. Cambrian. The largest ventral valve in the collection has a length of 10 mm.; width, 18 mm. Formation and locality.— Middle Cambrian: (31c and 54o) a About 900 feet (274.3 m.) above the Brigham quartzite and 3,300 feet (1,005.8 m.) below the Upper Cambrian in the limestone forming lb of the Ute limestone [Walcott, 1908f, p. 196], in Blacksmith Fork Canyon, about lO.miles (16.1 km.) east of Hyrum, Cache County, Utah. Eoorthis sp. undt. a (Pompeckj). Orthis sp., Pompeckj, 1896, Jahrb. K.-k. geol. Reichsanstalt for 1895, Bd. 45, Hft. 3, p. 514, PI. XV, fig. 6. (Charac- terized in German; see below for translation.) Orthis (Plectorthis) sp. (Pompeckj), Walcott (in part), 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 272-273. (Original description copied.) Tliis species appears, from the illustration given by Pompeckj [1896b, PI. XV, fig. 6], to belong to the genus Eoorthis. The material is too imperfect for specific determination. The original description is as follows: Some impressions of dorsal valves depart from Orthis romingeri. The ribs are remarkably broad, flat, and separated by narrow interspaces; ribs may be observed to be split several times. Formation and locality. — Middle Cambrian: (345 [Pompeckj, 1896b, p. 514]) Greenish shale in the Paradoxides zone, on the Dlouhd Hora, above the brook of Sbirov, near Skrej, Bohemia, Austria-Hungary. EooKTHis sp. undt. b (Pompeckj). Orthis sp. Pompeckj, 1896, Jahrb. K.-k. geol. Reichsanstalt for 1895, Bd. 45, Hft. 3, p. 514, PI. XV, fig. 7. (Char- acterized in German; see p. 793 for translation.) Orthis (Plectorthis) sp. (Pompeckj), Walcott (in part), 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 272-273. (Original description copied.) a Bio is the type locality. BILLINGSELLIDiE. 793 Pompeckj [1896b, p. 514] mentions another species of Orthis that appears to belong to the genus Eoortliis. The material, which is too imperfect for specific determination, was described as follows: The impression of a dorsal valve departs from Orthis romingeri in its greater breadth and less distinct ribbing. Formation and locality. — Middle Cambrian: (345e [Pompeckj, 1896b, p. 514]) Greenish shale in the Paradoxides zone in the gorge above Luh, near Skrej, Bohemia, Austria-Hungary. EooRTHis sp. undt. c (Walcott). Plate LXXXIX, figure 7. Orthis (Plectorthis) sp. undt. Walcott, 1906, Proc. U. S. Nat. Mus., vol. 30, p. 571. (These various shells are described and discussed essentially as below as sp. undt. c, d, and e.) This species is represented by a single specimen of the ventral valve. Ventral valve convex, with the apex curving gently downward from the liighest point to the cardinal area, transverse; length, 2.5 mm.; width, 3 mm.; liinge line a little shorter than the greatest width; cardinal area sloping slightly forward from the hinge line. Surface marked by about 16 strong, nearly regular, rounded, radiating ribs, that are crossed by fine, concentric striae, lines of growth, and one strong ridge indicating interiniption of growth. Observations. — Tlus httle shell was at first placed with EoortJiis agreste (Walcott) (PL LXXXIX, fig. 6), but further study showed that its greatest convexity, elevated apex, and stronger ribs distinguished it from that species. Formation and locality. — Middle Cambrian: (C26) Near the top of the black oolite group in the uppermost layers of the Changhia formation [Blackwelder, 1907a, p. 33 (part of the last list of fossils)]; 2 miles (3.2 km.) north- northeast of Changhia, Shantung, China. EooRTHis sp. undt. d (Walcott).'^ Plate LXXXIX, figure 8. A larger shell of the type of sp. undt: c occurs in Shensi, ua the central portion of the Kichou formation. It has a length of 6.5 mm. and a width of 7.5 mm. The surface is marked by numerous radiating ribs, similar to those of the shell from Changhia, also concen- tric strife and several ridges resulting from interruption of growth. Formation and locality. — Middle Cambrian: (C71) ilassive cliff-making limestones in the central portion of the Kichou formation [IMllis and Blackwelder, 1907, pp. 139 and 145 (2d list of fossils)], 4 miles (6.4 km.) south- southwest of Tungyu, Shansi, China. EooETHis sp. undt. e (Walcott)." A third shell that appears to be a dorsal valve was found associated with Mddle Cambrian trUobite fragments in hmestone pebbles in river gravel. The surface is partly exfoliated, but it shows rounded, radiatmg ribs and concentric ridges, similar to those on the two specimens described above as sp. undt. c and sp. undt. cl. Formation and locality. — Upper Cambrian: (C67) Stream gravels used in making the railroad grade, 0.33 mile (0.5 km.) west of the west city gate, Tsinan, Shantung, China. Genus FINKELNBTJRGIA Walcott. Orthis {Finkelnhurgia) Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 277-278. (Characterized and discussed as below as a new subgenus.) Finkelnhurgia Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 4, PI. XI, and pp. 142 and 148. (Classification of genus.) This genus is based upon two species that differ from Eoortliis in having thick shells and strongly marked vascular trunks in the ventral valve. The type of the genus, Finkelnhurgia ,finTcelnburgi. with its acunainate and sometimes alate cardinal extremities and subequally convex a See synonymy for JSoorthis sp. undt. c. 794 CMIBRIAN BRACHIOPODA. valve, is a very strong!}- marked type; the second species, F. osceola, has obtuse cardinal extrem- ities, and most of the examples closely resemble in I'orm Eoorthis remniclia (Winchell). It is only when the specimens from the fine-grained sandstone of Trempealeau are studied that one finds the thick shell and strong interior marldngs that are unknown in species of the genus Eoortliis. This genus is named after Mr. W. A. Fmkelnburg, of Winona, Minnesota, who has been one of the most intelhgent and enthusiastic collectors of Cambrian and' Ordoviciai; fossils in IV'Iinnesota in recent years. Type. — Orihis (Finlcelnburgia) Jinkelnburgi Walcott. FlNKELNBUEGIA FINKELNBUEGI (Walcott) Plate XCIII, figures 2, 2a-e. Orthis (Fitikelnburgia) Jinhelnburgi Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 278-279. (Described and dis- cussed as below as a new species.) Shell transverse \\dth the cardinal extremities acuminate and in some examples almost alate. On the ventral valve the Mnge hne slopes toward the beak at a low angle; in the dorsal valve it is nearly straight. There is considerable variation in the height and width of the shell, this feature depending upon the extension of the cardinal angles. The convexity of the valves is subequal. In some examples the ventral valve is much more elevated and convex than in others, and the same is true of the dorsal valve. A low, clearly defined mesial sinus occurs on the dorsal valve, being strongest in young shells, and there is frequently a flattening of the mesial area on the ventral valve. The surface is marked by fine, rounded, radiating costse, crossed by concentric hnes, and, occasionallj", ridges of growth. In a ventral valve 7 mm. in length, 11 mm. in width, there are two costse in a distance of 1 millimeter. The largest specimen of a ventral valve in the collection has a length of 10 mm. with a width of 18 mm. The average shell is less than 8 mm. in length. The cardinal area of the ventral valve is relatively high. It extends backward over the hinge hne at an angle varying from 15° to 45° from the plane of the valve. The delthyrium is of moderate mdth and apparently partly covered by a deltidium. The cardinal area of the dorsal valve averages about one-half the height of that of the ventral valve, although in some shells it is fuUy two-thirds as liigh. It extends backward at an angle of about 70° to the plane of the valve. It is divided midway by a strong delthyrium. None of the specimens in the collections show whether there was a cliihdium present or not. In the interior of the ventral valve the strong teeth were supported by dental plates that extend to the bottom of the valve and bound the umbonal cavity • (pseudospondyUum) . The only traces of the vascular system are the bases of strong vascular trunks, as shown in Plate XCIII, figure 2. The positions of the diductor and adductor muscle scars are shown in figure 2. The latter appear to have been carried into a very narrow space on an elevated ridge between the deep impressions raade by the main vascular trunks; in figure 2a the points of attachment of the muscles are well advanced into .the valve. In the interior of the dorsal valve a cast of the interior of the pseudocrurahum appears to have a smaU cardinal process, or callosity, but its presence is too doubtful to. state that the cardinal process is present; there are traces of a median septum shown on the central ridge toward the center of the valve. The carchnal process occurs in the anterior half of the umbonal cavity. The casts of the interior show that the crura are short and well defined, vnth relatively strong dental sockets beside them. The only traces of the muscle scars observed are those of the adductor, as shown in figure 2e. Observations. — The exterior surface and size of tliis shell recalls Finkelnburgia osceola (Walcott). It differs, however, in, the acuminate ventral angles and strongly convex dorsal valve. In form the elongate cardinal angles relate tlais species to Otusia sandhergi (WincheU),-= but in surface and interior markings it materially differs from the latter. STEOPHOMENID^. 795 The specific name was given in honor of Mr. W. A. Finkelnburg. Formation" and locality. — Upper Cambrian: (78 and 78s) "St. Croix sandstone," quarry near St. Croix River in subui'bs of Osceola, Polk County; (81) "St. Croix sandstone" 1 mile (1.6 km.) east-northeast of Devils Lake, Sauk County; (81b) "St. Croix sandstone" near Devils Lake, Sauk County; and (83, 83', 135b, and 135c)a "5£. Croix sand- stone" near Trempealeau, Trempealeau County; all in Wisconsin. (339f) "St. Croix sandstone" near Minneiska (Miniska) on Mississippi River near the line between Wabasha and Winona counties, Minnesota. FlIfKELNBURGIA OSCEOLA (Walcott) . Plate XCIII, figures 1, la-h. Orthis {Finkelnburgia) osccofa Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 279. (Discussed essentially as below as a new species.) The general form of this siiecies is similar to that of Eoorthis remnicha (Winchell) except that it is usually more transverse. It is a smaller shell, averaging for the ventral valve a length of 8 mm. and width of 11 mm., while, i?. remnicha averages 12 mm. in length and 14 to 16 mm. in width in the adult shell. The radiating costas are more uniformly rounded and regular, and more numerous, except when compared with the variety texana. The shell of Finkelnburgia osceola is tliick, hke other forms of the genus, with a result that the vascular markings are definitely outlined. In figure Id the vascular markings are beautifully shown; also, the large main vascular sinuses so characteristic of many species of Billingsella. The cardinal process and median septum are well brought out in the cast, figure If. Some of the dorsal valves approach quite closely to those of E. remnicha sulcata (Walcott) . The specific name is derived from Osceola, Wisconsin. Formation and locality. — Upper Cambrian: "St. Croix sandstone " at the following localities: (78 and 78s) Quarry near St. Croix River, in suburbs of Osceola, Polk County; (78b) 50 feet (15 m.) above St. Croix River, near the landing at Osceola, Polk County; (79a) quarry and ledge 0.5 mile (0.8 km.) southeast of the county comthouse, Menomonie, Dunn County; (80) 0.33 mile (1.1 km.) southwest of the railway depot, Menomonie, Dunn County; (79b) near Hudson, St. Croix County; (80a) 4 miles (6.4 km.) north of Reedsburg, Sauk County; (83, 83' and 135c)* near Trempealeau, Trempealeau County; (85x) near Mazomanie, Dane County; and (3381) 0.33 mile (1.1 km.) west of the railway station, Lodi, Columbia County; all in Wisconsin. (339g) Just below the Dicellocephalus minnesotensis zone, near Winona, Winona County, Minnesota. (341) Sandstone near Lansing, Allamakee County, Iowa. FlNKELNBtTRGIA OSCEOLA CORRUGATA (Walcott) . Qrihis (Finkelnburgia) osceola corrugata Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 280. (Characterized as below as a new variety.) At two of the localities at which Finkelnburgia osceola (Walcott) occurs there are also found a few specimens with strong concentric ridges formed by the piling up of lines of growth. The shell has a corrugated appearance that is very distinctive, and it is designated a variety. Formation and locality. — Upper Cambrian: (78 and 78s)6 "St. Croix sandstone," quarry near St. Croix River, in the suburbs of Osceola, Polk County, Wisconsin. (339g) Just below the Dicellocephalus minnesotensis zone, near Winona, Winona County, Minnesota. Superfamily STROPHOMENACEA Schuchert. FamUy STROPHOMENID^ King. Subfamily RAFINES QUINCE Scliucliert. Genus EOSTROPHOMENA Walcott. [jjtuf, dawn; and Strophomena (tTzflBtjiii, a twist; and /(//uij, the moon, a crescent).] Strophomena (Eostrophomena) Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 256. (Characterized as below as a new subgenus.) Eostrophomena Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 4, PI. XI, and pp. 142 and 148. (Classification of genus.) o83 is the type locality. !> 83' is the type locality. 796 CAJVIBRIAN BRACIilOPODA. The description of the type species gives all that is known of the genus. It differs from StropTiomena in having the cardinal process in the dorsal valve merged into a ridge formed by the extension of the crural plates along the posterior margin so as to cover the delthyrium and unite at the median line. Type. — Stropliomena {EostropTiomena) elegantula Walcott. Observations. — The cardinal process is more Hke tliat of Orihothetes than that of StropTiomena; it differs from both in being more simple in its construction. It is probable that there is a group of shells having the characters of Eostrophomena elegantula (Walcott) , but owing to the difficulty of obtaining interiors of the valves, it is impossible to designate them. StropJiomenM aurora Billings [1865a, p. 218] is one of these; also, Leptsena decipiens [BilUngs, 1862c, p. 74]. Eostrophomena elegantula (Walcott). Plate XCV, figures 6, 6a-b. Strophomena (Eostrophomena) elegantula Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 256-257. (Described and discussed as below as a new species.) Strophomena (Eostrophomena) roalcotti Moberg and SEGBKBERn, 1906, Medd. fran Lunds Geol. Faltklubb, Ser. B, No. 2 (Aftryck ur K. Fysiografiska Siillskapets Handl., N. P., Bd. 17), p. 71, PI. II, figs. 6, 6a-b ; PL III, fig. 16?. (Described and discussed in Swedish. The specific name "walcotti" is proposed because of the preoccupation of "elegantula." The generic value now assigned to Eostrophomena permits the use of "elegantula." Figs. 6, 6a-b, in common with the remaining figures on PL II of Moberg and Segerberg's paper, were copied from a preliminary photograph of PL XCV of this monograph.) General form transversely subsemicircular or subeUiptical, greatest width at the straight hinge line. Surface concavo-convex and marked by fine, radiating, even strife, separated into flat bands by stronger and more prominent strise or ribs; fine concentric strise, and more or less prominent lines of growth cross the radiating striae. The ventral valve is slightly convex, with low umbo and small, incurved apex. The dorsal valve is flattened in the umbonal region and concave toward the margins; the interior shows a narrow, rounded median furrow, also rounded crural plates that unite with the cardinal process to form a continuous ridge covering the anterior portion of the delthyrium; the dental sockets appear to have been relatively large and deep ; the adductor muscle scars are a little to the front, as shown in figure 6b. A ventral valve 6 mm. wide has a length of 4 mm., and a dorsal valve 5.5 mm. wide is 3 mm. in length. Observations. — The concavo-convex shells and the ridge representing the cardinal process place this little shell with the strophomenoid forms, but as no described genus possesses the characters shown a genus is made to receive it. Formation and locality. — Passage beds between the Upper Cambrian and the Ordovician: (310j) Ceratopyge limestone, at Borgholm; (310 [Moberg and Segerberg, 1906, description of PL III]) Ceratopyge limestone (Zone 4) at Ottenby; and (390e [Moberg and Segerberg, 1906, pp. 71 and 109]) " Apatocephalus zone of the Ceratopyge suite," at Ottenby; all on Oeland Island, Sweden. Superfamily PENTAJVIEKACEA Schuchert. Family SYNTROPHIID^S: Scliucliert. Genus SWANTONIA Walcott. "■ Swantonia Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 296. (Mentioned as below as a new genus.) Swantonia Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 4, PL XI, and pp. 142 and 148. (Classification of genus.) The description of the type species includes that of the genus, as there is only one other species now referred to the genus, and that is very imperfectly known. o Prior to the definition of the genus Swantonia the species now placed under that genus were referred to the following genera: Camerella Billings [1861b, p. 10; 1861c,p.949;1862e, p. 221; ise,?, p. 284J. Carmrella Walcott [1886b, p. 122; lS91a, p. 613). CamardU ? Hall and Clarke [1893, p. 220]. Protorhyncha? Schuchert [1897, p. 334]. SYNTROPHIID^^. 797 Type. — Camerella antigua Billings [1861b, p. 10]. The generic name is derived from the town of Swanton, Vermont, near which the type species occurs. SWANTONIA ANTIQUATA (Billings). Plate CIV, figures 5, 5a-b. Camerella antiquata Billings, 1861, Geol. Survey Canada, Paleozoic Fossils, vol. 1, pp. 10-11, fig. 13, p. 10. (De- scribed and discussed as a new species.) Camerella antiquata Billings, 1861, Report on the Geology of Vermont, vol. 2, p. 949, fig. 353. (Copy of preceding reference.) Camerella antiquata Billings, 1862, Report on the Economic Geology of Vermont, by Hager, p. 221, fig. 353. (Copy of Billings, 1861b, pp. 10-11, and fig. 13.) Camerella antiquata Billings, 1863, Geol. Survey Canada, Fifteenth Rept. Progress, fig. 290, p. 284. (No text refer- ence. Fig. 290 is copied from Billings, 1861b, fig. 13, p. 10.) Camarella antiquata Billings, Walcott, 1886, Bull. U. S. Geol. Survey No. 30, pp. 122-123, PI. VII, fig. 8. (Original description, Billings, 1861b, pp. 10-11, copied. The specimen represented by fig. 8 is redrawn in this mono- graph, PL CIV, fig. 5.) Camarella antiquata Billings, Walcott, 1891, Tenth Ann. Rept. U. S. Geol. Survey, p. 613, PL LXXII, fig. 3. (No text reference. Fig. 3 is copied from fig. 8 of the preceding reference.) Camarella f antiquata Billings, Hall and Clarke, 1893, Nat. Hist. New York, Paleontology, vol. 8, pt. 2, pp. 220-221. (Mentioned in discussion of genus Camarella.) Protorhyncha f antiquata (Billings), Schuchert, 1897, Bull. U. S. Geol. Survey No. 87, p. 334. (Merely changes generic reference.) Swantonia antiquata (Bilhngs), Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 296-297. (Described and discussed as below.) Ventral valve ovate, moderately convex; apex pointed and incurved over the area nearly to the plane of the margins of the valve; surface marked by from 8 to 12 or more rounded ribs that extend back well toward the apex; a slight flattening of the median portion suggests that a shallow median sinus may be found on old shells. The shell illustrated has a length and width of 11 mm. A cast of the interior of a ventral valve shows no traces of muscle scars or vascular mark- ings; two strong teeth are indicated, also a narrow, strong, concave shelf or area; the area or shelf is free from contact with the bottom of the valve, a recess or chamber existing beneath it. Observations. — The area or shelf may be considered as a short, free spondylium, corre- sponding to the short spondylium of . Camarella volborthi Billings as illustrated by Hall and Clarke [1892c, PI. LXII, fig. 18]. Swantonia is closely related to Camarella, but it difl^ers in the absence of a supporting median septum beneath the spondylium of the ventral valve. No specimens of the dorsal valve have been observed. Foemation and locality. — Lower Cambrian: (319e)a Sandy shale.s 2 miles (3.2 km.) east of Swanton, Franklin County, Vermont. Swantonia weeksi Walcott. Plate CIV, figure 6. Swantonia weehsi Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 297. (Characterized as below as a new species.) This shell has the general form of Swantonia antiquata (Billings), but the ribs are finer, more numerous, and crossed by fine, sharp, concentric striae. Only the exterior of the ventral valve appears to be represented in the collection made by Mr. F. B. Weeks. Formation and locality. — Lower Cambrian : (Iv) Shales of No. 3 of the Silver Peak group, Barrel Spring section [Walcott, 1908f, p. 189], 3 miles (4.8 km.) north of Valcalda Spring and 4 miles (6.4 km.) west-northwest of the Drinkwater mine. Silver Peak quadrangle (U. S. Geol. Survey), Esmeralda County, Nevada. a Billings [1861b, p. 11] gives the locality as 1.5 miles (2.4 km.) east of Swanton, Vermont. 798 CAIIBIIIAN BRACHIOPODA. Genus SYNTROPHIA Hall and Clarke. « Syntrophia Hall and Clarke, 1S92, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, footnote, p. 270. (Discusses species which appear to belong to a distinct genus and announces the future use of the term Syntrophia to include them.) Syntrophia Hall and Clarke, 1S93, idem, pt. 2, pp. 216-218. (Described and discussed as a new genus, copying the original note proposing the genus. The description of " Triplcsia lateralis^' Wiitfield, which is given on p. 217, is copied in this monograph; see below.) Syntrophia Hall and Clarke, Hall, 1894, Thirteenth Ann. Rept. State Geologist New York for 1893, vol. 2, pp. 836- 837. (Copies the description of "Triplesia lateralis " given on p. 217 of the preceding reference.) Syntrophia Hall and Clarke, Walcott (in part), 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 288-289. (Gives an essential copy of the description of "Triplesia lateralis" given by Hall and Clarke, 1893b, p. 217, a description which is copied below, and discusses the genus essentially as below. Species were included in the genus which are now placed under Huenella.) Syntrophia Hall and Clarke, Grabau and Shimer, 1907, North American Index Fossils, vol. 1, p. 270. (Described.) Syntrophia Hall and Clarke, Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 4, PI. XI, and pp. 142 and 148. (Classification of genus.) The description of " Trij^lesia lateralis" by Hall and Clarke [1893b, p. 217] follows: Shell transversely elongate, biconvex with a straight hinge line whose length nearly equals the greatest diameter of the valves, and each valve is medially divided by an open delthyrium. The external surface is smooth, with fine concentric lines visible only about the margins; the inner shell layers show a strongly fibrous radiating structure without punctation. The pedicle valve bears a more or less clearly developed median sinus and the brachial valve a broad, indistinct fold. On the interior the teeth are very small, lying at the extremities of the delthyrial margins and supported by dental plates which converge and unite before reaching the bottom of the valve. Thus is formed a deep but short spondylium, which is supported, near its apical portion, by a median septum, but is free for fully one-half its length. In the brachial valve there are also two convergent plates bounding the deltidial cavity, larger and stronger than those of the opposite valve. These plates may rest upon the bottom of the valve, and probably always do so toward the posterior extremity, but anteriorly they become free, forming a spondylium which is supported by a median septum extending beyond the anterior edge of the plate. Thus these two valves which are very similar in exterior, the pedicle valve being only slightly the more convex and with a low median sinus, are also closely alike on the interior, each being furnished with a spondylium . Type. — Triplesia lateralis Wbitfield. Observations. — Hall and Clarke [1893b, p. 216] referred Orthis barahuensis and Triplesia primordialis among Cambrian species to Syntrophia, and of Ordovician species, Triplesia lateralis, Strieldandiniaf aretliusa, S.f aracJme, and Camarella calcifera. OrtJiis? armada Billings, of the Lower Ordovician, certainly has a close resemblance in the spondylium of its ventral valve to this genus, and it may represent a radially striated form, as suggested by Hall and Clarke [1893b, p. 218]. Concerning the relations of Syntrophia to Strick- landinia, they consider that the structures represented in the species referred to the former genus may be the equivalents of those represented by the Stricklandinias of the later Silurian and Devonian. Billings [1862b, p. 84] noted the relationship existing between his Camarella calcifera and SiricMandinia. It is probable that S. ? arachne, S. aretliusa, and similar forms should be referred to a distinct genus. They are not typical Stricklandinias and they differ in surface and shape from Syntrophia lateralis. The Cambrian type of Syntrophia is S. rotundata of the Upper Cambrian. It has a spondyl- ium in each valve supported by a median septum, and a short area divided by a large open delthyrium. The structure of the shell of Syntrophia is fibrous, with rows of minute pores between the fibers. a The synonjrmy for this genus does not give a complete record of tlie various genera under which tlie species now included in Syntrophia were formerly placed; it gives only those references in which the genus is discussed or described. To complete the record for the species taken up in this monograph the following mere generic references are listed: Camerella Billings [1861a, p. 318; 1863, p. 231]. Orlhis A. Winchell [1864, p. 228]. Camerella Billings [1865a, p. 220]. Triplesia Whitfield [1878, p. 51]. icptona Whitfleld(1878, p. 60; 1882, pp. 171 and 195]. Triplesia Whitfield [1882, p. 172]. Triplcsia Walcott [1884b, p. 75]. Triplcsia Whitfield [1SS6, p. 303]. Triplecia Hall and Clarke [1892e, p. 270). SYNTROPHIIDiE. . 799 All of tlie species of the Svntrophiid» witli nonplicated, smooth surface and spondylium raised on a median septum are referred to SyntropMa, and the species with a more or less phcate surface, with sessile spondylium or pseudospondylium, to the genus Huenella. The nonplicate or smooth species are: S. camhria and S.f unxia of the Middle Cambrian; S. alata, S. harahuensis , S. camphelli, S. orthia, S. primordialis, and S. rotundata of the Upper Cambrian; and S. calcifera, S. lateralis, and S. nundina of the Ordovician. Syntrophia alata Walcott. Plate cm, figures 3, 3a-e. Syntrophia alata Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 290. (Characterized as below as a new species.) This species is characterized by its transverse form and extended cardinal angles. Exterior surface marked by concentric striae and lines of growth and interior surface by fure, radiating striae. A transverse section of the ventral valve at the umbo shows the spondylium with a strong median septum supporting it. The. interior of the ventral valve was marked by two strong main vascular sinuses starting from the sides of the spondylium. FoHMATiON AND LocALrTY. — TTpper Cambrian: (69) Limestone near Honey Creek, Bm-net County, Texas. Syntrophia barabuensis (A. Winchell). Plate CII, figures 1, la-g. Orthis harahuensis A. Winchell, 1864, Am. Jour. Sci., 2d ser., vol. 37, p. 228. (Described and discussed as a new species.) Leptsena barabuensis (Winchell), Whitfield, 1878, Ann. Kept. Wisconsin Geol. Survey for 1877, p. 60. Leptsena barabuensis (Winchell), Whitfield, 1882, Geology of Wisconsin, vol. 4, pt. 3, pp. 171-172, PI. I, figs. 6 and 7. (Described and discussed; see below for copy.) Leptsena barabuensis Winchell, Whitfield, 1882, idem, p. 195, PI. Ill, fig. 6. (Described from a higher horizon than that containing the specimens referred to in the preceding.) Syntrophia barabuensis (Winchell), Hall and Clarke, 1893, Nat. Hist. New York, Paleontology, vol. 8, pt. 2, p. 216. (Changes generic reference.) Syntrophia barabuensis (Winchell), Walcott, 1905, Proc. U. S. Nat. Mus., vol. 27, pp. 290-291. (Description by Whitfield copied, and species discussed as below.) The description by Wliitfield [1882, pp. 171-172] follows: Shell of medium size or smaller, measuring about half an inch or less than half an inch along the hinge line; form semielhptical, longest on the hinge and more than half as wide again as long; extremities of the hinge often sub- mucronate; front of the valves rounded or slightly emarginate in the middle. Ventral valve the most convex, and marked by a strong, angular mesial elevation, nearly one-fourth as wide on the front of the valve as the width of the shell; area moderately high and nearly in the plane of the valve; cardinal borders very gradually sloping from the center to the extremities of the cardinal line. Dorsal valve less convex than the opposite, and marked by a suban- gular mesial depression, corresponding to the fold of the opposite valve; area linear. Surface of the shell apparently smooth, or at least so far as can be determined from either the internal casts or from the matrix. I had some doubt regarding the positive identity of this species with that described by Professor Winchell [1864, p. 228] in consequence of the following remarks which occur in his description: "Surface with sixteen or eighteen ribs visible on the casts, the strongest of which limit the mesial sinus," and again, "apparently of the type of Orthis biforta." In examining a number of specimens, I had not been able to detect any strise or ribs, and felt somewhat inclined to regard it as a distinct species from that one. I have, however, thi'ough the kindness of Prof. W. [Winchell], been able to make a direct comparison with one of his original specimens, and should consider them as identical. The specimen sent me has the mesial fold (of the ventral valve) remarkably strongly defined by a depressed line on each margin, the center appearing tumid, which I think is in part due to accident. The specimen corresponds closely with the ventral valve we have figured, except in the strongly defined mesial fold. Observations. — Tliis is the same type of SyntropMa as S. primordialis. It differs in its more rounded outhnes, shallow, rounded sinus in the ventral valve, and, usually, a less pro- nounced fold on the dorsal valve. Evidence of a short median septum at the end of a very sliort spondylium in tlie dorsal valve is sliown by one cast (PI. CII, fig. Ig). Tlie species derives its specific name from its occurrence at Devils Lake, which is near Baraboo, Sauk County, Wisconsin.' Formation and locality. — Upper Cambrian: "St. Croix sandstone " at the following localities: (328 [Whitfield, 1S8'2, p. 172]) Upper layers near the north end of Devils Lake, Sauk County; (81b) near Devils Lake, Sauk County; (81o) 800 CMIBRIAN BRACHIOPODA. on the railroad track below the Cliff House, Devils Lake, Sauk County; (83) near Trempealeau, Trempealeau County; (78) quarry near St. Croix River in the suburbs of Osceola, Polk County; and (134a) in a quarry 1 mile (1.6 km.) south- east of the county coiu-thouse in Menomonie, Dunn County; all in Wisconsin. r Syntrophia calcifera (Billings) Plate CIV, tigm-es 1, la-i. Cmnerella calcifera Billings, 1861, Canadian Naturalist, vol. 6, pp. 318-320, figs. 3a-c, p. 319. (Described and discussed as a new species. Figs. 3a-c are copied in this monograph, PI. CIV, figs. 1, la, and lb, respectively.) Cainarella calcifera Billings, 1863, Geol. Survey Canada, Fifteenth Rept. Progress, figs. 247a-c, p. 231. (No text reference. Figs. 247a-c are copied from figs. 3a-c of the preceding reference.) CamereJla calcifera Billings, 1865, Geol. Sm-vej' Canada, Paleozoic Fossils, vol. 1, p. 220. (Localities mentioned.) Triplecia? calcifera (Billings), Hall and Clarke, 1892, Nat. Hist., New York, Paleontology, vol. 8, pt. 1, p. 270. (Merely changes generic reference.) Syntrophia? calcifera (Billings), Hall and Clarke, 1893, idem, pt. 2, p. 218, PL LXII, fig. 24. (Changes generic reference.) Syntrophia calcifera differs from S. nundina in its more pointed and incurved apex, stronger ventral sinus, and dorsal fold. It is more convex and rotund than S. j^rimordialis. The only interior parts known are in the form of a cast illustrated by Billings [lS61a, fig. 3c, p. 319] and copied in Plate CIV, figure lb; tliis indicates a weU-developed spondylium and a median supporting septum in the ventral valve. The form owes its specific name to its occurrence in the "calciferous sandrock." Formation and locality. — Lower Ordovician: (3191)^ "Calciferous sandrock" at St. Timothy on the St. Law- rence, near the head of the Beauharnois Canal; (319u [Billings, 1861a, p. 320]) " calciferous sandrock " in the Township of Edwardstown, between Beauharnois and Lake Champlain; (392)" at Nortons Creek; (392j)a lime- stones of the "Quebec group" at Point Levis; and (3921)" limestone at Phillipsburgh; all in the Province of Quebec, Canada. ' (314c) o Nodules of white limestone belonging to Division P of Billings's section at Cow Head, Newfoundland. Syntrophia CAMBRIA Walcott. Text figures 72A-D. Syntrophia cambria Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, pp. 106-107, PI. X, figs. 11 and 11a. (Described and discussed as a new species. With the ex- ception of the third paragraph the reference is copied below. Figs. 11 and 11a are copied in this monograph as figs. 72B and 72C, re- spectively.) General form transversely oval, strongly convex but not rotund. Ven- tral valve moderately convex, •with the frontal margin in adult" shells prolonged ; a flattened median sinus begins on the umbo and widens to two-tliirds the width of the shell in front; area un- known. Dorsal valve moderately convex except on the median fold, which is rounded but not unusually prominent; area unknown. Surface marked by a few concentric lines of growth. The largest dorsal valve has a length of 8 mm.; width, 11 mm. A ventral valve 9 mm. in length has a width of 14 mm. C D Figure 72. — SyvtropMa cambria Walcott. A, A', Top view and side outline of ventral valve (U. S. Nat. Mus. Cat. No. 57029a). B, Ventral valve, the type specimen (U, S. Nat. Mus. Cat. No. 52477a). C, Dorsal valve (U. S. Nat. Mus. Cat. No. 52478). D, Partly exfoliated ventral valve (U. S. Nat. Mus. Cat. No. 52477c). Figures 72B and 72C are copied from Walcott [190Sd, PI. X, tigs. 11 and Ua]. The specimen represented by figure 720 is from Locality 34m; those represented by figures 72A,72B, and 72D are from Locality 32e; and that represented by figure 72A is from LocaUty 31c, all in the Middle Cambrian of northeastern Utah. a Billings, 1865a, p. 220. SYNTROPHIIDtE. 801 Observations. — In form this species is usually most nearly related to Syntrophia calcifera (Billings) (PI. CIV, figs. 1, la-i). It differs in ha"ving a less clearly defined beak and less promi- nent fold on the dorsal valve. There are many points in common between Syntropliia cambria and S. nundina Walcott (PL CII, figs. 4, 4a-c), but they differ in the shorter beak and sharper median fold of the latter. Syntrophia cambria occurs in the Wasatch range, about 4,500 feet below the base of the Ordovician, wlxile S. calcifera and S. nundina occur in the Lower Ordovi- cian. It is the oldest species of the genus and is of interest also on account of being closely related in form to the Ordovician species mentioned. Formation and LOCALiif . — Middle Cambrian: (31c and 54o) 900 feet (274.3 m.) above the Brigham quartzite and 3,300 feet (1,005.8 m.) below the Upper Cambrian, in the limestone forming lb of the Ute limestone [Walcott, 1908f p. 196], in Blacksmith Fork Canyon, about 10 miles (16.1 km.) east of Hyrum, Cache County; (32e) the same strati- graphic horizon as Locality 31c just south of the south fork of Paradise Dry Canyon (East Fork), east of Paradise Cache County; and (34m) limestone about 765 feet (233.2 m.) above the Brigham quartzite [Walcott, 190Sa, p. 8], 1 mile (1.6 km.) northwest of Geneva (Copenhagen), east of Brigham, Boxelder County; all in Utah. Syntrophia campbelli Walcott. Text figures 73A-F. Syntrophia campbelli Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, pp. 107-108, PI. X, figs. 9, 9a-c. (De- scribed and discussed as below as a new species. Figs. 9, 9a-c are copied in this monograph as figs. 73B 73C 73E, and 73F, respectively.) General form rotund, unequally biconvex; hinge line short. Ventral valve moderately convex, exclusive of the prolonged frontal margin; it is depressed toward the front in adult FiGUEE 73.— Syntrophia campbelli Walcott. A, Ventral valve, the type specimen (U. S. Nat. Mus. Cat. No. 52480f). B, Cast of ventral valve, showing cast of septum supporting the spondylium (U. S. Nat. Mus. Cat. No. 52480a). C, C, Dorsal valve (U. S. Nat. Mus. Cat. No. 52480b). D, Dorsal valve (U. S. Nat. Mus. Cat. No. 524S0e). E, Section of ventral valve, showing cast of septum and spondylium (U. S. Nat. Mus. Cat. No. 52480c). F, Cast of dorsal valve, showing cast of spondylium (U. S. Nat. Mus. Cat. No. 62480d). The specimens represented are from Locality 12q, Upper Cambrian, near Rogersville, Tennessee. Figures 73B, 73C, 73E, and 73F are copied from Walcott [1908d, PI. X, figs. 9, 9a-c, respectively). shells by a broad median sinus that disappears on the umbo ; area short and divided midway by a relatively large, open, triangular delthyrium. Dorsal valve convex with an elevated, rela- tively narrow median fold that does not extend back to the beak; area short and divided by a strong, open, triangular delthyrium. Surface marked by concentric striae and a few strong lines of growth. The largest shell is represented by a dorsal valve that has a length of 12 mm.; width, 14 mm. A ventral valve 7 mm. in length has a width of 1 1 mm. Casts of the ventral valve show a spondylium supported on a septum that extended from the beak about one-third the distance to the front margin. The spondylium of the dorsal valve rests directly on the interior of the shell without trace of a supporting median septum. 62667°— VOL 51, ft 1—12 51 802 CAJMBRIAN BEACHIOPOUA. Ohservations. — The .young shells of this species are almost evenly convex, the fold of the dorsal A^alve and the sinus of the ventral valve of the adult shell not having developed. The characteristic spondylium of each valve is shown in the youngest shells observed. The general form of Syntropliia campheTli is much like that of Syntrophia rotundata Walcott (PI. (Til, figs. 4, 4a-c) and somewhat like that of Huenella texana (Walcott) (PI. CIII, figs. 1, la-g). It differs from the former in having the spondjdium of the dorsal valve resting on the interior of the shell and not supported on a septum, in this respect resembling the spondylium of IlueneUa texana (Walcott) (PI. CIII, figs. Ih, li). Some shells have a somewhat transverse posterior margin like that of H. texana, but the larger number have the broadly acununate outline of 5. rotundata. The muscle scars of the dorsal valve, as far as known, are similar to those of Huenella ahnorm.is (Walcott) (PI. CIII, figs. 2i, 2s). The specific name was given in honor of Mr. M. E. Campbell of the United States Geological Survey, who collected the specimens. Formation and locality. — Upper Cambrian: (12q) Knox dolomite, on Bunker Hill, 6 miles (9.6 km.) northeast of Rogersville [Keith, 1905, areal geology sheet], Hawkins County, Tennessee. Stntrophia lateralis (Whitfield)., Text figure 11, page 299; Plate CII, figm-es 6, 6a-g. . Triplesia lateralis Whitfield, 1886, Bull. Am. Mus. Nat. Hist. No. 8, p. 303, PL XXIV, figs. 9-11. (Described as anew species.) Syntrophia lateralis (Whitfield), Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, footnote, p. 270. (Generic reference changed.) Syntrophia lateralis (Whitfield), Hall and Clarke, 1893, idem, vol. 8, pt. 2, p. 217, PL LXII, figs. 1-10. (Described, giving on p. 216 the footnote referred to in the preceding reference. The description of this species is copied in this monograph, under the genus Syntrophia. Figs. 9 and 10 are copied in this monograph, PL CII, figs. 6f and 6g, respectively.) Syntrophia lateralis ("WTiitfield), Hall and Clarke, 1894, Thirteenth Ann. Rept. State Geologist New York for 1893, vol. 2, pp. 836-837, PL XLV, figs. 7-12. (Copy of the description given on p. 217 of the preceding reference. Figs. 7-12 are copied from Hall and Clarke, 1893b, PL LXII, figs. 1, 2, 6, 9, 5, and 10, respectively.) I have illustrated a few of the shells representing the species that, taken with those of Hall and Clarke in part 2 of volume 8 of their great work, illustrate about all that is known of S. lateralis. (See p. 798 for a copy of Hall and Clarke's description of the species.) Foemation and locality. — Lower Ordovician: (227) Limestone near Fort Cassin, Addison County, Vermont. Syntrophia nundina Walcott. Plate CII, figures 4, 4a-d. Triplesia calcifera Walcott [not Billings], 1884, Mon. U. S. Geol. Survey, vol. 8, pp. 75-76, PL XI, figs. 7 and 8. (Characterized. The specimens represented by figs. 7 and 8 are redrawn in this monograph, PL CII, figs. 4 and 4a, respectively.) Syntrophia nundina Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 292. (Characterized as below as a new species.) Syntrophia calcifera Walcott, Grabau and Shimer, 1907, North American Index Fossils, vol. 1, p. 271, figs. 325. (De- scribed. The two figui'es in fig. 325 are copied from Walcott, 1884b, PL XI, figs. 7 and 8, respectively.) The nonplicats, convex species that is found in the Lower Ordovician of the western United States has usually been referred to Cam.erella or Triplesia calcifera. It is much like the latter but differs in being less convex, with apex of valves less pointed and incurved. Formation and locality. — Lower Ordovician: Pogonip limestone at the following localities: (63) Northeast of Adams Hill; (201a) east slope of the ridge east of Hamburg Ridge; (203) on spur on ridge extending southwest from Wood Cone; (204) on the lower part of the eastern slope of the ridge east of Hamburg Ridge, facing Secret Canyon road; and (209) on the west side of Goodwin Canyon; all in the Em-eka district [Hague, 1892, Atlas], Eureka County, Nevada. (185z) Limestones at the base of the Lower Ordovician [Walcott, 1908f, p. 191], in Blacksmith Fork Canyon, about 9 miles (14.4 km.) east of Hyrum, Cathe County, Utah. (186 and 186a) Near line of contact between red and gray Ordovician limestone, in red siliceous limestone, 30 to 35 feet (9.1 to 10.7 m.) above the pre-Cambrian rocks, Williams Canyon, Manitou, El Paso County, Colorado. Upper Cambrian: (54b) About 1,200 feet (365.8 m.) above the Middle Cambrian and 25 feet (7.6 m.) below the top of the Upper Cambrian in the upper part of the limestone forming 1 of the St. Charles formation [Walcott, 1908f, SYNTROPHIID^. 803 p. 191]; and (54c) about 1,100 feet (335.3 m.) above the Middle Cambrian and 120 feet (36.6 m.) below the top of the Upper Cambrian in the central part of the limestone forming 1 of the St. Charles formation [Walcott, 1908f, p. 192]; both in Blacksmith Fork Canyon about 10 miles (16.1 km.) east of Hyrum, Cache County, Utah. A specimen (PI. CII, fig. 4d) that is somewhat doubtfully referred to this species occurs at the following locaUty: Upper Cambrian : (329a) Limestone on Ute Peak, in the Wasatch Mountains east of Cache Valley, Cache County, Utah. Syntrophia oethia Walcott. Plate CIV, figures 4, 4a-b. Syntrophia orthia Walcott, 1905, Proc. U. S. Nat. Mus., vol. 29, pp. 11-12. (Described and discussed as a new species.) General form irregularly oval, with the ventral view obtusely angular toward the apex; rounded, biconvex, with a deep mesial sinus on the ventral valve and a strong median fold on the anterior half of the dorsal valve. Surface smooth, with the exception of a few concentric strise and lines of growth. The ventral valve has a strong median sinus that occupies about one-third of the width of the_ valve at the anterior margin and projects forward to fit into the sinus in the front of the margin of the dorsal valve ; the sides of the median sinus are elevated, and with the downward-sloping lateral slopes form a strong, rounded ridge on each side of the sinus; none of the specimens in the collection show the area, but from the profile of the valve it must have been of moderate height, with a rather sharp apex curving over it. Dorsal valve with a minute apex, from which a narrow, slightly developed median fold extends to about the posterior fourth of the shell, where it becomes elevated, and, widening, extends forward to the front margin ; the remaining portions of the surface are uniformly convex, sloping away from the median fold to the margins of the valve. Nothing is known of the interior of either valve. Observations. — In general form this species resembles Syntrophia primordialis (Whitfield) of the "St. Croix sandstone" of Wisconsin. It differs in its more rounded, irregularly oval form and the very large median sinus of the ventral valve. Formation and locality. — Upper Cambrian: (C54) Lower pait of the Chaumitien limestone [Blackwelder, 1907a, p. 42 (part of last list of fossils)], 0.66 mile (1.1 km.) west of Tsinau; (C56) same horizon as Locality C54 at Pagoda Hill [Blackwelder, 1907a, p. 42 (part of last list of fossils)], 1 mile (1.6 km.) west of Tsinan; and (C64) upper limestone member of the Kiulung group [Blackwelder, 1907a, pp. 37 and 42 (first list of fossils), and fig. 10 (bed 20), p. 38], 2.7 miles (4.3 km.) southwest of Yenchuang, Sintai district; all in Shantung, China. Syntrophia primordialis (Whitfield). Plate CII, figures 2, 2a-e. Triplesia primordialis Whitfield, 1878, Ann. Kept. Wisconsin Geol. Survey for 1877, p. 51. (Described.) Triplesia primordialis Whitfield, 1882, Geol. Wisconsin, vol. 4, pt. 3, p. 172, PI. X, figs. 1 and 2. (Described and discussed, the first paragraph being copied below.) Triplecia? primordialis Whitfield, Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, p. 270, footnote. (Questions generic reference.) Syntrophia primordialis (WTiitfield), Hall and Clarke, 1893, idem, pt. 2, p. 218. (Changes generic reference.) Syntrophia primordialis (Whitfield), Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 292. (Whitfield's description, 1882, p. 172, copied and species discussed as below.) The description by Whitfield [1882, p. 172] follows: Shell small, measuring less than half an inch in width; transversely oval in outline, and quite ventricose in profile- hinge line straight and about half as long as the width of the shell below; area narrow. Ventral valve with a strongly depressed, rather narrow and rounded mesial sinus. Dorsal valve with a narrow, sharply elevated fold not extending quite to the beak; sides of the valve rounded. Surface smooth in the casts, but presenting the appearance of having been externally striate. Processes in the interior of the dorsal valve apparently forming a small spoon-shaped pit at the beak. Ohservations . — Casts of the interior show the form of the spond3dium and supporting median septum in the ventral valve ; also, a small short spondylium in the ventral valve, which appears to be attached to the bottom of the valve without a median septum. 80-t CMDBRIAN BRACHIOPODA. This species differs from SyntropMa barabuensis (Winchell) in its smaller size, less trans- verse outline, and more pronounced mesial depression on the ventral valve. Some specimens of the dorsal valves of the two species are very similar. These are shown by Plate CII, figures If and 2c. Some of the shells approach certain forms of S. calcifera, but the larger number are less convex and more transverse and with more obtuse cardinal angles. A shell closely allied to S. primordialis , and apparently identical, occurs in the limestone of the Reagan sandstone of Oklahoma. Only the exterior is known. Formation and locality. — TTpper Cambrian: "St. Croix sandstone" at the following localities: (99) Minneiska (Miniska), on Mississippi River, near the line between Wabasha and Winona counties; (339d) Taylors Falls, Chisago County; (84a) at River Junction, Houston County, 20 miles (32.2 km.) below Dresbach, and (339g) just below the BiheUocephalus jninnesotensis beds, near Winona, Winona County; all in Minnesota. (328k) "St. Croix sandstone" at Roche a Oris Bluff, Adams County, Wisconsin. (9u) About 195 feet (59.4 m.) above the porphyry contact in the limestones of the Reagan sandstone, in SE. J NE. i sec. 2, T. 4 N., R. 13 W., 15 miles (24,2 km.) northwest of Fort Sill, Comanche County; and (12n) limestones of the Reagan sandstone (in the section 7 miles (11.2 km.) north of Springer this horizon is about 240 feet (73 m.) above the porphjTy contact and 40 feet (12 m.) below the Arbuckle limestone), NW. J sec. 1, T. 2 S., R. 1 E., Ardmore quad- rangle (U. S. Geol. Survey), Carter County; both in Oklahoma. (168) Limestones on north side of Tepee Creek, near the road from Sheridan to Dome Lake, Bighorn Mountains, Sheridan County, Wyoming. Stnteophia primordialis argia Walcott. Plate CII, figure 3. JSyntropUa primordialis argia Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 293. (Characterized as below as a new variety.) This specimen is separated as a variety of SyntropMa primordialis (Whitfield) on account of its less convexity and more shallow median sinus, which has three rudimentary plications in it. Formation and LOCALrrY. — Upper Cambrian: (97) "St. Croix sandstone" at Reads Landing, foot of LakePepin, Wabasha County, Minnesota. Syntrophia rotundata Walcott. Plate cm, figures 4, 4a-e. SyntropMa rotundata Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 293-294. (Described and discussed as below as a new species.) General form rotund, unequally biconvex; hinge line short. Surface marked by fine, concentric striae and low, imbricating varices of growth. The largest shell observed has a width of 13 mm.; length, 11 mm. Ventral valve convex at the umbo and beak, but depressed toward the front by a strong, broad, and deep median sinus. Area low, short, and divided midway by a relatively large triangular delthyrium. Transverse sections of the umbo near the beak show the cross section of a well-developed spondylium supported on a median septum. Dorsal valve about as convex as the ventral on the umbo, but the strong, broad median fold makes it strongly convex. Cross sections at the umbo show a spondylium and supporting septum very much like that in the ventral valve. Olservations. — This species is taken as the Cambrian representative of the genus Syn.- trophia. It has a spondylium in each valve supported by a median septum in the same manner as in the Ordovician type of the genus S. lateralis. Its rotund form, deep ventral sinus, and strong dorsal fold serve to distinguish S. rotundata from other species of the genus. Formation and locality.— Upper Cambrian: (14k) Limestone on Wolf Creek, 15 miles (24.2 km.) west-south- west of Sheridan, Bighorn Mountains, Sheridan County, Wyoming. Stntrophia? unxia Walcott. Text figure 74, page 805. SyntTophia? unxia Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, pp. 108-109, PI. X, fig. 10. (Discussed as below as a new species. Fig. 10 is copied on p. 805 as fig. 74.) This species is represented by a single specimen of the ventral valve from which the shell has been removed by weathering. The cast of the spondylium shows it to have been SYNTROPHIID^. 805 of the same type as that of the ventral valve of SyntropMa primordialis (Whitfield) (PI. CII, figs. 2, 2a-b) and S. harahuensis (Winchell) (PI. CII, figs. 1, la-d). The elongate, rounded form and scarcely perceptible median sinus serve to distinguish this species from all described forms. This is the oldest shell of this tj^pe kno\vn to me. It occurs 5,525 feet below the summit of the Cambrian, in the House Range section. I am not full}' satisfied with the generic refer- ence, but with the data available it can not well be referred to Billingsella or any other known genus of the Cambrian Brachiopoda. Formation and locality. — Middle Cambrian : (3x) About 2,200 feet (670.6 m.) above the Lower Cambrian and 2,200 feet (670.6 m.) below the Upper Cambrian, in the limestones forming Id of the Marjum limestone [W^alcott, 1908f, p. 180], 2.5 miles (4 km.) east of Ante- lope Springs, in ridge east of '\Mieeler Amphitheater, House Range [Walcott, 1908f, Pis. XIII and XV], Millard County, Utah. _ u I i-i^'-vT-cT T A ITT 1 J.J. „ FiGUEE 74.— SyntTopliia? unxia Genus HUENELLA Walcott. « ^^^,^^^j ^^^^^^^ ^^^^^^ SyntropMa Walcott (in part) [not Hall and Clakke], 1905, Proc. U. S. Nat. Mus., vol. 28, which" the shell has been pp. 288-289. (Described and discussed essentially as on p. 798 (under SyntropMa), entirely removed by weath- but some of the species included in the genus are now referred to Huenella.) m'^^o^' f pv' ^"^" ^^^' Huenella Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, p. 109. (Characterized Sx, in the Middle Cambrian and discussed as below as a new genus.) House Range, Utah. Copied Huenella Walcott, 1908, idem. No. 4, PI. XI, and pp. 142 and 148. (Classification of fromjValcott[i908d,Pl.X, genus.) fig. 10]. This genus is proposed to include the more or less plicate species of the Syntrophiidse that have heretofore been referred by me to the genus SyntropMa. They differ from SyntropMa in having a more or less radially plicate surface and sessile or pseudospondylia instead of free spondylia supported by a median septum. With the exception of Huenella vermontana and possibly H. etheridgei, all of the species are from the Upper Cambrian. The shell structure is fibrous, with many minute pores. Type. — SyntropMa texana Walcott [1905a, p. 294]. The generic name is given in recognition of the thorough and valuable work of Dr. Fr. von Hoyningen-Huene on the "Silurischen Craniaden." Huenella abnoemis (Walcott). Text figure 13, page 299; Plate CIII, figures 2, 2a-m. Not Camerella calci/era Billings, 1861, Canadian Naturalist, 1st ser., vol. 6, No. 4, p. 318. (Referred in this mono- graph to Si/nfropfe'a cafcj/era.) Camerella calci/era Meek [not Billings], 1873, Sixth Ann. Rept. U. S. Geol. and Geog. Survey Terr, (for 1872), p. 464 and footnote. (Characterized.) SyntropMa abnonnis Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 289-290. (Described and discussed as below as a new species.) The general form varies from transverse (PI. CIII, fig. 2) to elongate (fig. 2c). Valves biconvex, with dorsal very convex in some specimens. Hinge line straight. Surface marked by concentric strise and imbricating lines of growth crossed by fine, rounded, radiating striag and a variable number of rounded ribs; specimens occur with four ribs in the sinus of the ventral valve and four on each slope outside the sinus; in other ventral valves only a trace of ribs can be seen; among the specimens of the dorsal valve there are shells without a sign of ribs, figtu-e 2d, and others having from a trace of ribs on the median fold to three ribs on the fold and traces on the lateral slopes. The largest shell has a length of 7 mm. ; mdth, 9 mm. There is great variation in the proportion of the length to the width, as shown by the figures illustrating the species. a Prior to the definition of the genus Huenella the species now referred to that genus were' described under the following genera; Camerella Shumard [1S61, p. 221]. I Orlhis or Orlhmna Etheridge [1905. p. 250]. Camerella Heek [1873, p. Ki]. I Sj/n(rop/iia Walcott [1905a, p. 28S]. 806 CMIBRIAN BRACHIOPODA. The ventral valve has a broad, strong sinus that depresses the front of the valve; area well defined, with a large, open delthyrium. Casts of the interior of the ventral valve show a well-marked spondylium and very strong main vascular sinuses, figure 2b; both spondylium and sinuses recall those of BiUingseUa plicateUa (PI. LXXXVI, figs. 3g, 3j). Sections of the ventral valve, cut across the umbo, show the spondylium attached to the bottom of the valve. The flabellifonn diductor and adductor muscle scars are clearly shown outside of the vascular sinuses. Dorsal valve with an elevated median fold that gives a strong convexity to the valve; area low, with, a strong, open delthyrium; the interior of the valve shows a shallow spondylium attached to the bottom of the valve posteriorly, and probably supported by a low median septum toward the front (figs. 2i, 2j, section fig. 2m) and well-defuied anterior and posterior adductor muscle scars; narrow main vascular sinuses occur (fig. 2h), and slender vascular lines radiate forward from the muscle scars (fig. 2f). Observations. — This species differs from all allied forms in its variation in outline, con- vexity, ribs, and mternal markings. Some shells approach closely to those of Huenella texana (Walcott) (compare figs. 1 and 2 and figs, lb and 2a, PI. CIII), but each species has a majority of shells that are quite unhke those of the other. Another point of resemblance is the form of the spondjdium as sho\vn by cross sections. A variety of H. texana from Cold Creek Canyon, Texas, has some shells that approach those of H. ahnormis in the extravagant development of the fold on the dorsal valve and smus on the ventral valve, but in other respects they differ from it. The form of spondylium and plications or ribs suggests the genus ParastropMa Hall. This form was an abnormal representative of the genus SyntropMa, to which it was first referred, hence the specific name. Formation and locality. — Upper Cambrian: (153) Limestone in ravine on west side of Dry Creek, near the mouth of Pass Creek, about 5 miles (8 km.) north of Hillsdale; and (157 and 158) limestone north of East Gallatin River, near Hillsdale; both on the Threeforks quadrangle (U. S. Geol. Survey), Gallatin County, Montana. (302p) Middle limestone of the Deadwood formation, near the summit of the Owl Creek Mountains, 18 miles (29 km.) southwest of Thermopolis, Fremont County, Wyoming. Middle Cambrian: (4j) Limestone at the head of Deep Creek, Yellowstone National Park, Canyon quadrangle (JI. S. Geol. Survey), Wyoming. HXJENELLA BILLINGSI (Walcott). Plate CII, figures 5, 5a-c. Syntrophia billingsi Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 291-292. (Described and discussed as below as a new species.) General form transversely subquadrate; rounded; biconvex, with the dorsal valve elevated on the median fold. Surface marked by a few imperfectly developed ribs on some shells, while others have only concentric strije and lines of growth. Ventral valve with a relatively shallow median sinus, in which obscure, narrow ribs sometimes occur; none of the specimens in the col- lection show the area, but from the profile of the valve it must have been of moderate height, with the rather sharp apex curving slightly over it; a single poor cast of the interior shows the outline of a spondylium much like that of S. primordialis; the evidence of the presence of a median septum is a dark line in front of the end of the cast of the spondylium, which indicates that the shell substance extends down into the limestone and that it is the median septum. Dorsal valve with a small umbo and apex that extend forward into a prominent median fold that may be plicated (PI. CII, fig. 5c) or smooth; one partly exfohated shell shows three plica- tions on the fold and three or four on each lateral slope of the valve. Ohservations. — This species belongs to the plicate group of the Syntropliiidse represented by Huenella texana (Walcott) and H. ahnormis (Walcott). It dififers from H. texana in being less convex and in having a shallower ventral sinus, less prominent dorsal fold, and more obscure plications. The specific name was given in honor of Mr. E. Billings. Formation and locality. — Middle ? Cambrian: (28a) "St. Albans formation," in limestone lentil about 1 mile (1.6 km.) east of Parker's quarry, west of Georgia, Franklin County, Vermont. SYNTROPHIIDiE. 807 HUENELLA ETHERIDGEI Walcott. Plate LXXXIX, figures 9, 9a. Orthis (or Orthisina) sp. Etheridge, 1905, Trans. Roy. Soc. South Australia, vol. 29, p. 250, PI. XXV, figs. 9 and 10. (Described as below and discussed. The specimens represented by figs. 9 and 10 are redrawn in this monograph, PI. LXXXIX, figs. 9 and 9a, respectively.) Huenella etheridgei Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, pp. 109-110, PL X, figs. 13 and 13a. (Described and discussed as below, copying the original descriptions. Figs. 13 and 13a are drawn from the specimens represented by figs. 9 and 10 of the preceding reference and are copied in this monograph, PL LXXXIX, figs. 9a and 9, respectively.) Doctor Etheridge describes the ventral valve as follows: Subquadrilateral, convex, the greatest convexity at about midway in the length of the valve, the sinus gradually deepening and widening toward the front, and bounded laterally by ill-defined folds, one on either side, the surface sloping away on either side rapidly to the lateral margins, and at a very much less angle within the sulcus; there are indications of costse on the divaricating folds and in the sulcus. The hinge features are hidden in matrix, nor is the umbo distinctly visible. He describes the dorsal valve as follows: Rotundato-quadrate, the cardinal margin as long as the width of the valve, the surface convex, except on the dorso-lateral alations, where it appears to be flattened. There is a central, acute, or pinched-up fold, produced forward, and expanding as it advances. There are indications of the existence of strong, distinct, subradiating costse. Whether or no this is the brachial valve of the species represented by the preceding form it is at present impossible to say; the two occur in the same bed, however. From the study of the various forms of Huenella described herein, I think that the two valves belong to one species, and I take pleasure in naming it after Dr. R. Etheridge, jr. Formation and locality. — Middle? Cambrian: (315c [Etheridge, 1905, p. 250]) "Archseocyathinae white lime- stone " at Wirrialpa, Flinders Range, South Australia. Huenella lesleyi Walcott. Text figures 75A-C. Huenella lesleyi Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, p. 110, PL X, figs. 12 and 12a. (Characterized and discussed as below as a new species. Figs. 12 and 12a are copied in this monograph as figs. 75B and 75A, respectively.) Only the exterior of the valves of tliis species is known. In form and outline it is most nearly related to Huenella texana (Walcott). It differs from the latter in being broader in proportion to its length, and in having narrow, radiating, rounded ribs over the entire surface. A' B FiGUKE 75.— Huenella lesleyi Walcott. A, A', Exterior of partly exioliated dorsal valve (U. S. Nat. Mus. Cat. No. 52481b). B, Exterior of ventral valve, the type specimen (U. S. Nat. Mus. Cat. No. 524Sla). C, Exterior of ventral valve (U. S. Nat. Mus. Cat. No. 52481c). The specimens represented are from Locality S4b in Blacksmith Fork Canyon, Cache County, Utah. Figures 75A and 75B are copied from Walcott [190Sd, PI. X, figs. 12a and 12, respectively]. This is probably the oldest HueTieUa. It occurs 1,025 feet (312.4 m.) below the summit of the Upper Cambrian. Billingsella coloradoensis (Shumard) and Lingulella manticula (White) occur in the same bed of limestone. The specific name is given in honor of the late Dr. J. P. Lesley, state geologist of Pennsylvania. Formation and locality.— Tipper Cambrian: (54e) About 200 feet (61 m.) above the Middle Cambrian and 1,025 feet (212.4 m.) below the top of the Upper Cambrian in hmestones forming 3 of the St. Charles formation [Walcott, 1908f , p. 193], in Blacksmith Fork Canyon, about 10 miles (16.1 km.) east of Hyrum, Cache County, Utah. SOS C-UIBRIAX BRACHIOPODA. HUEXELLA ORIEXTAUS (Walcott). Plate CIV, figures 3, 3a-b. SifntTvphia orienialis Waicott, 1905, Proc. T. S. Xat. Miis.. vol. 2S, p. 292. (Characterized and discussed as below as a new species.' This species is closely related in form and surface characters to HueneUa texana (Walcott) and some forms of H. ahnonnis (TValcott). It differs from them in details of surface ribs. On the dorsal valve there are two or three faintly defined radiating ribs on each side of the median fold, which has obscure ribs upon it. Corresponding ribs occur upon the mesial depression of the ventral valve and the side slopes adjoining the depression. The material representing it is too limited to warrant an identification with any described species. H. orientulis is the trans- Pacific representative of H. texana. FoBMATiox AXB LOCALTTT. — ^TTpper Cambrian: (C64) Upper limestone member of the Kiulung group [Blapk- ■welder, 1907a, pp. 37 and 42 (,first hst of fossils), and fig. 10 (bed 20), p. 38] 2.7 miles (4.3 km.) southwest of Yenchuai^, Sintai district. Shantung, China. HuEXEiXA TEXA2CA (TTalcott). Plate cm, figures 1, la-i. Camerella sp.? SffTiiASD, 1861, Am. Jour. Sci., 2d ser., vol. 32, p. 221. (Mentioned; see below for copy.) Syntrophia texana 'Walcott, 190-5, Proc. TJ. S. Ifat. 3Ius., vol. 28, p. 294. (Original mention copied and species dis- cussed as below as a new species.) This may be called the plicate representative of the group of species referred to the Syntro- phiidse. It is intimately connected with the smooth forms by a series of shells that vary from 16 ribs on a valve to 1; the extremes are shown by Plate CIII, figures Id and le. In form H. texana is much like H. ahnormi-s (Walcott); also in the cross section of its spondylium. They differ in the extravagant development of the plications of H. texana, a feature characteristic of a large series of specimens. The average size of the larger shell is width, 8 nun.; length,. 6 to 7 mm. It is probable that this is the shell referred to by Dr. Shumard [1S61, p. 221] as Camerella sp.?. He said of it: There are several specimens of a small brachiopod in the Texas state collection, from the Potsdam sandstone of Morgans Creek, Bumet Countj", which appear to belong to the genus Camerella recentiy created by Mr. E. Billings. T7nfortunately, however, they consist merely of detached and imperfect valves too much weathered for satisfactory determination and description. Formation- axd localitt. — Upper Cambrian: (68) Inierbedded sandstone and limestone, Pachsaddle Mountain, Llano County; (71) limestone in Cold Creek Canyon, Bumet County; and (69) limestone near Honey Creek, Bumet Cotmtj-; all in Texas. Huexella texaxa L^vnrscT7i.rs (Walcott). Syntrophia texana Imviitsculus Walcott, 1905, Proc. V. S. Xat. Mus., vol. 28, pp. 294—295. (Characterized and dis- cussed as below as a new varietj'.j A variety occurs in Texas with a few traces of plication in the sinus: and with one, two, or three strong pHcations on the dorsal fold, or none at aU; it approaches HueneUa ahnormis (Walcott) in some of its extreme forms where the ribs are large on a prominent mesial fold. In most young shells the sinus and fold are inconspicuous, the convexity is verj" moderate, and the shell smooth: nearlv all the characters of the adult are missing. SYXTPvOPHIID-E. 809 A group of young shells from Honey Creek sho^vs only the smooth, slightly convex forms, with only shght ventral sinus and dorsal fold. One larger shell associated ■vs'ith the young shells has a relatively deep sinus and a trace of a pUcation. Formation and localttt. — Upper Cambrian: (69) Limestone near Honey Creek; and (71) limestone in Cold Creek Canyon; both in Burnet Count}", Texas. HUEXEIXA VERMOXTAXA U. Sp. Test figure 76. It is somewhat FIGT3E 76. — EueneOa termontana n. sp. view of a specimen. A', Dorsal view of samespeei- men. A", Side view of the same specimen, showing the two valves nnited. The specimen is ftom Locality 319s, near St. Al- bans, Vermont (U. S. Xat. llns. Cat. No. 5S312). The convesdtv of the two valves This species is represented by a single specimen of the two valves united imperfect near the beaks. Valves moderately and about eciually convex, with the dorsal valve subcircular in outline and the ventral more elongated at the beak. Hinge short; cardinal angles rounded. Surface marked by low, concentric ridges of growth and numerous fine, rounded, radiating ridges that in- crease in number from the umbo to the margin by both bifurcation and interpolation of new ridges. A low, moderately broad sinus occurs on the anterior half of the ventral valve and a narrow median fold on the dorsal valve. "Where the surface of the shell is exfo- Hated the sheU appears to be minutely punctate. The ventral valve has a length of 11 nun. ; width, 9 mm. is 6 mm. Ohservations. — This shell differs from all known species of HucneUa by its finely ribbed surface. In this respect it recalls Swantonia antiquaia (Billings) (PI. CI\^, fig. 5). It occurs in association with Paradoxides in an intraformational conglomerate. Formation' axd localttt. — Middle Cambrian: (319s'i "St. Albans formation," at St. Albans, FranMin Countj-, Vermont. Genus CLAEKELLA Walcott. « Clarhella Walcott, 1908, Smithsonian Misc. Coll., vol. -53, Xo. 3, pp. 110-111. (Described and discussed as below as a new genus.) Clarkella Walcott, 1908, idem, vol. .53, Xo. 4, PI. XI, and pp. 142 and 148. (Classification of genus.) General form rotund, unequally biconvex. Surface smooth or marked by concentric strife and lines of growth. Ventral valve convex at the umbo and with a strong, broad median sinus; area low and divided by a relatively large delthj-rium. Dorsal valve convex at the um^bo, which is extended forward into a strong, broad median fold. Cross sections of the valves near the apex and beneath the umbo show a spondyhum supported by four or more septa that divide the umbonal cavity into five chambers. Thin sections of the shell of the type species show it to be fibrous and with many minute pores arranged in lines radiating from the beak to the front and side margins of the valves. Type. — PolyfacJtia ? inontanensis Walcott. This genus is known only by the type species from the Lower Ordovician of Montana. It is distinguished from. Polyfachia HaU and Clarke [lS92c, p. 2.39] by an open delthyrium, smooth surface, and presence of septa and spondyhum in the dorsal valve. It differs from Syntrophia and HueneUa in having several septa supporting the spondyhum, and also from HueneUa in having a smooth nonplicate surface. The generic name is given in recognition of the work of Prof. Jolin M. Clarke, of the Geo- logical Survey of New York, in connection with Prof. James Hall, on the fossil Brachiopoda. o Prior to the definition of the genus Clarkella the type species was placed under Polgtaehia [Walcott, 1905a. p. 295]. 810 CAIIBRIAN BRACHIOPODA. Clarkella montanensis (Walcott). Plate CIV, figures 2, 2a-d. Polyt(Echia? montanensis Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 295-296. (Characterized and discussed as below as a. new species.) This shell was placed with Camerella calcifera until sections were made showing the numerous septa supporting the spondylium and cruralium. In general form it is close to SyntropMa rotundata Walcott, differing in the numerous supporting septa of the spondylium which divide the umbonal cavity into five chambers. The material available for study does not show the area in very good preservation; a delthyrium exists in the area of the ventral valve, which is all that can be said. This species appears to be a direct descendant of the smooth, convex forms of SyntropMa, like S. rotundata. Formation and locality. — Lower Ordovician : (302j) Limestone on the east side of West Gallatin (Gallatin) River, above Gallatin, Gallatin County, Montana. INDEX In this index black-face figures refer to locality numbers, light-face figures refer to pages. The main refer- ence to each genus and species (the page reference which is usually put in black-face type under the old scheme of lumping all references together, or the page reference which will be used in the futm-e synonymy of the genus or species) is given first and is invariably preceded by the word "described," even if the genus or species is little more than mentioned on the page given. References to the description of certain features of a species or to comparisons with other species are indexed only if the description or comparison occiu-s on some other page than the one on which the species is described. The table of synonymic references, on pages 27-98, may be regarded as a completely cross-referenced index to the synonymy in the monograph, as each name in that table is there given in the form in which it appears in the synonymy of the species to which it is now refeiTed. This index therefore includes only those synonjonic references that appear in connection with the description of the genera and species, all synonyms being placed in quotation marks. This index gives the numbers of all the localities in any country, province. State, county, district, or place, as well as the numbers of all the localities identified from the different formations or other stratigraphic units. These numbers are tabulated on pages 160-291, where full information is given as to species included, authority for citation, correlation and comparison with other localities, and the stratigraphic section (pp. 123-159) in which the locality is placed or with which it is correlated. For these reasons this index includes no reference to the localities ^ven in connection with the description of the species. The names of species given under the heading "Locali- ties," on pages 160-291, are not indexed as appearing on those pages, but the page on which each brachiopod there named is described appears in the index, and on this page are given not only the numbers but detailed descriptions of all localities from which the species has been identified. Geographic names that have been passed on by the United States Geographic Board are spelled in accordance ■with that board's decisions, but a few variant familiar spellings have been inserted in the index with cross references. Abe Lincoln mine, near Pioche, Nevada, locality at 333 Abingdon quadrangle, Massachusetts, locality in 326b Ableman, Wisconsin, locality at 328q abnormis, see Huendla. Abrigo limestone (Middle Cambrian), locality in 14x Acadian, generalized section of, listing species and localities 132-133 acadicas, see Obolus, Acerocare zone, in generalized section for Sweden, Denmark, Fin- land, and Norway, listing species and localities 145 locality in 309e Acknowledgments 11 (Acriii3)fSee Obolus (Acritis). ^CTothele, described 630 cardinal area discussed 305 classification of 321,324 compared with Acrothele (Redlichella) 662, 663 Acrotreta 314 AcTotreta and Acrothyra 313 Acrotreta definita 683 Acrotreta gemmula 686 Botsfordia 601, 602 Discinopsis gulielmi 721 *' Linnarssonia" 673 Schizopholis ■ 608, 609 Yorkia 611 -development of 314 •distortion of shells of 654 evolution discussed 319 evolution of 317 general geographic and stratigraphic distribution of the species referred to 105 general stratigraphic distribution and number of Cam- brian species and varieties of. Ill mentioned 656, 661, 674 number of Ordovician species and varieties of 113 jiumber of species of, in the different types of sedi- ment 160 Acrothele— Continued. pedicle tube discussed 314 reference to, of Acrothele nitida discussed 651 reference to, of Acrothele pretiosa discussed 705 reference to, of Acrotreta inchoans discussed 690 reference to, of Acrotreta ? minima discussed 695 species of. grouped under surface characters 632-633 surface ornamentation discussed 301, 302 type species Acrothele coriacea 632 vascular markings discussed 311 '^abavia", discussed 635 artemis, described 634 general geographic and stratigraphic distribution tabu- lated 105 type specimen figured text fig. 54, 634 avia, described 634 . compared with Acrothele avia puteis 636 A crothele proles 654, 655 general geographic and stratigraphic distribution tabu- lated 105 in group based on surface characteristics 632 surface ornamentation discussed 302 type specimen figured PI- LXI, fig. 7a avia puteis, described 636 general geographic and stratigraphic distribution tabulated 105 in group based on surface characteristics 632 type specimen not figured. "barbata," described and discussed 640 bcllapunctata, described 636 compared with Botsfordia pulcJira 633 Micromitra {Iphidella) pannula 633 general geographic and stratigraphic distribution tabulated 105 stratigraphic position mentioned 318 surface ornamentation discussed 302 type specimen figured PI- LVII, fig. 3 811 812 CAMBRIAN BRACPIIOPODA. AcTOthele bellula, described 637 cardinal area discussed 305 compared with. Acrotreta definita 631 discussed 631 general geographic and stratigraphic distribution tabulated 105 pedicle tube discussed 314 surface discussed 632 t j^e specimen figured : PI. LVIII, fig. 5 bergeroni, described 638 compared witti Acrothele coriacea 643 Botsfordia f barraTidei 603 discussed 633 general geographic and stratigraphic distribution tabulated 105 in group based on surface characteristics 632 type specimen figured PI. LVIII, fig. 6c bohemica, described 639 compared with Acrothele bergeroni 638 Acrothelc coriacea 643 Acrothele quadiilineata 655 general geographic and stratigraphic distribution tabulated 105 in group based on surface characteristics 632 type specimen figured PI. LVII, fig. 1 borgholmcnsis, described 639 compared with Acrothele ceratopygarum 640 A crothele tumeri 660 general geographic and stratigraphic distribution tabulated 105 in group based on surface characteristics 632 type specimen figured Fl. LXIII, figs. 2 and 2a ceratopygarum , described 640 compared with Acrotreta seebachi 710 discussed 634 general geographic and stratigraphic distribution tabulated 105 in group based on surface characteristics 632 type specimen figured PI. LXIII, figs. 1 and la colleni, described 640 compared with Acrothele panderi 651 MiCTomitra (Faterina) wapta 357 general geographic and stratigraphic distribution tabu- lated 105 in group based on surface characteristics 632 type specimen figured PI. LXIII, fig. 6 coriacea, described , 642 compared with " Acrothele barbata" 640 Acrothele bergeroni 638 Acrothele bohemica 639 Acrothele colleni 641 Acrothele intermedia 646 Acrothele levisensis 646 Acrothele matthewi 648 Acrothele panderi 651 Acrothele quadrilineata ' 655 Acrothele suhsidua 668 Acrothele (Redlichella) 662 Acrothele {Redlichella) granulata 663 Botsfordia granulata 606 general geographic and stratigraphic distribution tab- ulated 105 in group based on surface characteristics 632 surface ornamentation discussed 302, 632 type of A crothele 632 type specimen not figured. decipiens, described 644 general geographic and stratigraphic distribution tab- ulated 105 in group based on surface characteristics 632 stratigraphic position mentioned 318 type specimen figured PI. LVIII, fig. 3a dichotoma, described 644 general geographic and stratigraphic distribution tab- ulated 105 in group based on surface characteristics 633 type specimen figured PI. LX, fig. 2 .4 crothele gamagei, described 645 general geographic and stratigraphic distribution tab- ulated 105 in group based on surface characteristics 632 type specimen not figured. granulata, type of Acrothele {Redlichella) 632, 663 "cf. granulata Matthew," discussed 648-649 intermedia, described 646 general geographic and stratigraphic distribution tab- ulated 105 in group based on surface characteristics 632 type specimen figured PI. LVI, figs. 3 and 3a levisensis, described 646 general geographic and stratigraphic distribution tab- ulated 105 in group based on surface characteristics 632 tj'pe specimen figured PI. LXXXI, fig. 12 maculata, described 647 compared with A crothele villaboimensis 660 general geographic and stratigraphic distribution tab- ulated 105 in group based on surface characteristics 632 type specimen figured ^ PL LVII, fig. 2b matthewi, described 647 compared with Acrothele avia 635 A crothele avia puteis 636 Acrothele coriacea 643 Acrothele decipiens : 644 A crothele gamagei 646 A crothele matthewi multicostata 650 Acrothele nitida 651 Acrothele pretiosa 652 A crothele prima 653 Acrothele prima costata 653 Acrothele suhsidua 658 Acrothele yorkensis 661 Acrothele (Redlichella) granulata 632 Botsfordia cselata 632 Botsfordia granulata 632 general geographic and stratigraphic distribution tabu- lated 105 in group based on surface characteristics 632 surface discussed 632, 633 type specimen figured PI. LXI, fig. la varieties discussed 649 "matthewi costata" discussed 649 matthewi eryx, described 649 compared with Acrothele coriacea 643 Acrothele matthewi 649 general geographic and stratigraphic distribution tabu- lated 105 in group based on surface characteristics 632 type specimen figured PI. LXI, fig. 2 matthewi lata, described 649 discussed 649 general geographic and stratigraphic distribution tabu- lated 105 in group based on surface characteristics 632 type specimen figured PI. LXI, fig. 3 mMthewi multicostata, described 650 compared with Acrothele matthewi 648 Acrothele prima costata 654 discussed 649- general geographic and stratigraphic distribution tabu- lated 105- in group based on surface characteristics 632: surface ornamentation discussed.... 302 type specimen not figured. "matthewi prima, ^' discussed 649 ? minuta, described 650 general geographic and stratigraphic distribution tabu- lated 105 in group based on surface characteristics 632. type specimen figured PI. LXIII, fig. 3- nitida, described 650i general geographic and stratigraphic distribution tabu- lated '.. 105 in group based on surface characteristics 632 type specimen figured PI. LVIII, fig. 4 INDEX. 813 A crothele panderi, described 651 general geographic and stratigraphic distribution tabu- lated 105 in group based on surface characteristics 632 type specimen figured PI. LIX, fig. 5 preliosa, described 652 general geographic and stratigraphic distribution tabulated 105 in group based on surface characteristics 632 stratigraphic position of beds containing, discussed . - . 705 type specimen not figured. prima, described 653 compared with Acrothele avia 636 Acrothdc bohemica 639 Acrothele prima costata 653 Acrothele proles 655 general geographic and stratigraphic distribution tabulated 105 in group based on surfece characteristics 632 surface discussed 633 type specimen figured PI. LXI, fig. 6 prima costata^ described 653 compared with A crothele artemis 634 Acrothele bohemica 639 A crothele matthewi multicostata 650 A crothele prima 652 general geographic and stratigraphic distribution tabulated 105 in group based on surface characteristics 632 surface ornamentation discussed 302, 633 type specimen not figured. pnmseva, described 654 general geographic and stratigraphic distribution tabulated 105 i n group based on surface characteristics 633 type specimen figured PI. LVII, fig. 6 proles, described 654 compared with A crothele avia 636 A crothele matthewi 648 general geographic and stratigraphic distribution tabulated 105 in group based on surface characteristics 632 type specimen figured PI. LXII, fig. 4 guadrilineata, described 655 compared with A crothele bergeroni 638 Acrothele coriacea 643 Acrothele primxva 654 general geographic and stratigraphic distribution tabulated 105 in group based on surface characteristics 632 type specimen figured PI. LVn,fig. 5 rara, described 655 general geographic and stratigraphic distribution tabulated 105 in group based on surface characteristics 633 type specimen figured PI. LXIII, fig. 4 spurri, described 656 compared with Acrothele subsidua 658 A crothele subsidua hera 659 A crothele turneri 660 A crothele woodworthi 661 general geographic and stratigraphic distribution tabulated 105 in group based on surface characteristics 632 type specimen figured PI, LX, fig. 3 a, described 656 compared with Acrothele dicliotoma 645 Acrothele maculata 647 Acrothele rara 655 Acrothele spurri 656 Acrothele subsidua hera 659 Acrothele subsidua Ixvis 659 A crothele turneri 660 Acrotreta idahoensis 633 Acrotreta sagittalis taconica 633 general geographic and stratigraphic distribution tab- ulated 105 in group based on surface characteristics 632 surface ornamentation discussed 302 type specimen figured PI. LX, fig. 1 Acrothele subsidua hera, described 659 general geographic and stratigraphic distribution tab- ulated 105 in group based on surface characteristics 632 type specimen figured PI. LX, fig. 9 subsidua Issvis, described 659 compared with A crothele subsidua 658 general geographic and stratigraphic distribution tab- ulated 105 in group based on siurface characteristics 632 tjT)e specimen not figured. turneri, described 660 general geographic and stratigraphic distribution tab- ulated 105 in group based on surface characteristics 632 type specimen figured PI. LX, fig. 7 mllaboimensis, described 660 general geographic and stratigraphic distribution tab- ulated 105 in group based on surface characteristics 633 type specimen not figured. woodworthi, described 661 compared with Acrothele spurri 656 general geographic and stratigraphic distribution tab- ulated -■ 105 in group based on surface characteristics 632 stratigraphic position mentioned 318 tj-pe specimen figured PI. LX, fig. '& yorkensis, described 661 compared with Acrothele sp. undt. a 662 general geographic and stratigraphic distribution tab- ulated 105 in group based on surface characteristics 632 type specimen figured PI. LIX, fig. 4 sp. undt. a, described 662 general geographic and stratigraphic distribution tab- ulated 105 in group based on surface characteristics 633 type specimen figured PI. LXIII, fig. 5 sp. undt. Moberg, described 662 general geographic and stratigraphic distribution tab- ulated 105 in group based on surface characteristics 633 Acrothele (Redlichclla), described 662 cardinal area discussed 305 classification of 321, 324 evolution of 317 general geographic and stratigraphic distribution of the species referred to 105 general stratigraphic distribution and number of Cambrian species and varieties of ill intermediate between Bots for dia and Acrothele 663 number of species of, in different types of sediment. . . 160 type species "Acrothele granulata'^ 632,663 granulata, described 663 compared with A crothele bellapunctata 637 Acrothele bohemica 639 A crothele coriacea 643 Acrothele intermedia 646 Acrothele matthewi 632, 648 Acrothele panderi 651 Acrothele rara 655 Acrothele subsidua 658 A crothele yorkensis 662 Botsfordia granulata 602 general geographic and stratigraphic distribution tabulated 105 intermediate between Acrothele coriacea and Botsfordia granulata 663 surface of, confused with that of Acrotreta socialis 712 surface ornamentation discussed 302 type specimen not figured. Acrothelinse, classification of 321, 324 genera and species referred to, described 630-665 A crothyra, described 715 cardinal area discussed 305 classification of 321, 324 compared with Acrothele and Acrotreta 313 Acrotreta? cancellata 679 Discinopsis 721 814 CMIBRIAN BRACHIOPODA. ^cro/Ayra— Continued. evolution discussed 319 evolution of 317 general geographic and stratigraphic distribution of the species referred to 106 general stratigraphic distribution and number of Cambrian species and varieties of HI number of species of in different types of sediment 100 pedicle tube discussed 314 position assumed by shells in settling to the bottom discussed '^10 reference to, of Acrothyra mimor discussed 717 reference to, of Acrotreta inflata discussed 691 reterenceto, of some of Matley's species discussed 703 surface ornamentation discussed 301, 302 type species ".-1 crotrcta proavia " "Ih vascular markings discussed 311 minor, described ' 1 ' general geographic and stratigraphic distribution tabulated 106 type specimen nguied PI- LXXVI, flg. 4 proavia, described ^1^ compared mth Acrothyra signata 719 Acrothyra signata orta 719 general geographic and stratigraphic distribution tabulated 106 position assumed by shells in settling to the bottom discussed 716 type specimen not figured. varieties discussed 716 "proavia crossa," discussed 717 "proavia primi," discussed 717 sera, described 718 compared with ylcro(fi!/ra siynate pr/mo 720 general geographic and stratigraphic distribution tabulated 106 species and varieties referred to, discussed 716 type specimen not figured. signata, described 719 compared mth A crothyra proavia 71S A crothyra sera ^ 718 A crothyra signata orta 719 Acrothyra signata prima 720 general geographic and stratigraphic distribution tabulated 106 type specimen figured PI- LXXX, flg. 1 varieties discussed 716 signata orta, described 719 general geographic and stratigraphic distribution tabulated 106 type specimen figured PI. LXXX, fig. 3a sj^Tioto priTna, described 720 general geographic and stratigraphic distribution tabulated 106 type specimen flgiu'ed PI. LXXX, flg. 2 "signata sera," compared -ftdth "Acrotreta papillata" 716 reference U) Acrothyra sera discussed 716, 718 ' ' signata tarda ,' ' reference to A crothyra sera discussed 716, 718 Acrotreta, described 671 cardinal area discussed 305 classification of 321. 324 compared mth Acrothele 314,631,633 Acrothele und Acrothyra 313 A crothele decipiens 644 Acrothele matthewi 648 Acrothele ^Eedlichella) grannlata 712 Acrothyra 716 Botsfordia 602 Biccllomus 312,572 Di^cinolepis granulata 664 Linnarssonella 665 Linnarsson^lla minuta 668 Quebecia 611 Schizopholis 314, 602, 608 evolution discussed 319 evolution of 317 general geographic and stratigrapliic distribution of the species referred to 105-106 general stratigraphic distribution and number of Cam- brian species and varieties of HI Acrotreta — Continued. geographic and stratigraphic distribution discussed . . 674' mentioned 312. 527, 686, 687,715 muscle scars discussed 312 ntunber of Ordovician species and varieties of 113 number of species of, in different types of sediment. . 160 oldest species 701 only species from upper Mississippi Valley 711 pedicle tube discussed 314 position assumed by shells in settling to the bottom discussed 716 reference to, of Acrotreta incUoans discussed 690 reference to, oi Acrotreta inflata discussed 691 reference to, of some of Matley's sisecies discussed 703 surface ornamentation discussed 301,302,674 type species Acrotreta subconica 673 argenta, described 674 compared with Obolella 673 Obolus 673 general geographic and stratigraphic distribution tabulated .• 105 muscle scars discussed 313 type specimen figured PI. LX VII, fig. Sb attenuata, described 675 compared with A crotreta definita 683 Acrotreta gemma 685 Acrotreta idahoensis alia 689 Acrotreta Icutorgai 692 A crotreta m icroscopica 7nissourien,sis 694 Acrotreta ophirensis 69/ A crotreta primaeva 700, 701 false area in, discussed 674 general geographic and stratigraphic distribution tabulated 105 position asstimed by shells in settling to the bottom discussed 715 type specimen figured PI. LXIV, fig. 1 attenuata var.?, described '. 676 general geographic and stratigraphic distribution tabulated 105- type specimen figured PI. LXV, fig. 2 babel, described 676 general geographic and stratigraphic distribution tab- ulated ;.. 105 type specimen figured PI. LXXVII, figs. 6 and 6a baileyi, described 676 discussed ~ 673 general geographic and stratigraphic distribution tab- ulated 105 type specimen figured '. PI. LXXVII, fig. 2- bellatula, described 677 general geographic and stratigraphic distribution tab- ulated 105- type specimen figured PI. LXXVIII, fig. 4 belli, described 678. general geographic and statigraphic distribution tab- ulated 105 type specimen figured PI. LXXVII, fig. S- bisecta, described 67S compared with A crotreta kutorgai 692 Acrotreta sabrinse 703 Obolus ( Westonia) ella 674 general geographic and stratigraphic distribution tab- ulated 105- type specimen not figured. ?? cancellata, described 679' general geographic and stratigraphic distribution tab- ulated 105 surface ornamentation discussed 302, 672 type specimen figured PI. LXXIX, fig. 5 carinata, described 679 compared with Acrotreta circularis 680 general geographic and stratigraphic distribution tab- ulated 105 type specimen figured text figs. 66A-C, 680' circularis, described 680 compared with Acrotreta carinata 680 general geographic and stratigraphic distribution tab- ulated 105 type specimen figured text figs. 57A-D, 680 INDEX. 815 Acrotreta claytoni, described 680 general geograpliic and stratigraphic distribution tab- ulated 105 surface features mentioned. — 672 tj^e specimen figured PI. LXXIV, fig. 3 coTicentnca, described 681 general geographic and stratigraphic distribution tab- ulated 105 type specimen figured PI. LXXVII, fig. 1 conula, described 681 general geographic and stratigraphic distribution tab- ulated 106 type specimen figured Fl- LXXV, fig. 2b convexa, described 682 compared with Acrotreta gemmula 686 general geographic and stratigraphic distribution tabulated 106 type specimen figured PI- LXVI, fig. 6 "? costata," discussed 674 CUTvata, described 682 cardinal area discussed 305 compared with A crotreta idahoensis 688 Acrotreta microscopica 693 A crotreta ophirensis 697 Acrotreta sagUtalis transversa 673 Acrotreta ulrichi 714 general geographic and stratigraphic distribution tabulated 106 type specim.en figured PI. LXVin, fig. la definita, described 683 cardinal area discussed 305 compared with A crotreta bellatula 678 Acrothele bellula 631, 637 Acrotreta rudis 702 general geographic and stratigraphic distribution tabulated 106 type specimen figured PI. LXIV, fig. 2c depressa, described 683 compared mth A crotreta definita 683 A crotreta rudis 702 general geographic and stratigraphic distribution tabulated 106 type specimen figured PI. LXVI, fig. 8 eggegrundensis, described 684 general geographic and stratigraphic distribution tabulated 106 stratigraphic position of bowlder containing 454, 864 type specimen figured PI. LXX, figs. 2a^c emmonsi, described 684 general geographic and stratigraphic distribution tabulated 106 stratigraphic position mentioned 318 type specimen figured PI. LXV, fig. 6 gemma'; described 685 I compared with .A croireia depressa 683,684 A crotreta ovalis 699 Acrotreta schmalenseei 709 discussed 673 general geographic and stratigraphic distribution tabulated 106 mentioned 675, 691 species referred to mentioned 673, 689 type specimen figured PI. LXVI, fig. 1 gemmula, described 686 compared with Acrothyra proavia 717 Obolus ( Westonia) ella 674 general geographic and stratigraphic distribution tabulated 106 type specimen figured PI. LXVI, fig. 3a gracia, described 687 general geographic and stratigraphic distribution tabulated 106 type specimen figured PI. LXVI, fig. 5a "Igulielmi," type ot Discinopsis ^ 720 idahoensis, described 687 compared with Acrothele suhsidua 633 Acrotreta argcnta 674 Acrotreta curvata 682 Acrotreta definita 683 Acrotreta idahoensis— Continued. compared with A crotreta eggegrundensis 648 Acrotreta emmonsi 684 Acrotreta cf. idahoensis.. 688 A crotreta idahoensis alta 689 Acrotreta marjumensis 693 Acrotreta microscopica 693 A crotreta microscopica tctoncn^is 694 A crotreta nehocnsis 696 A crotreta pyxidicula 701 Acrotreta signalis 71i A crotreta spinosa 713 false area in, discussed 674 general geographic and stratigraphic distribution tab- ulated 106 position assumed by shells in settling to the bottom discussed 716 stratigraphic distribution mentioned 674 type specimen figured PI. LXV, fig. lb cf. idahoensis, described 688 general geographic and stratigraphic distribution tabulated '.. 106 idahoensis alta, described 689 compared with Acrotreta attenuata 675 A crotreta depressa 683, 684 Acrotreta gemma 685 Acrotreta idahoensis sulcata 690 A crotreta pacifica 699 general geographic and stratigraphic distribution tabulated 106 stratigraphic distribution mentioned 674 type specimen figured PI. LXV, fig. 4a idahoensis sulcata, described 690 compared with A crotreta lisani 693 A crotreta uplandica 714 general geogi-aphic and stratigraphic distribution tabulated 106 type specimen figured PI. LXV, fig. 5 inchoan^, described - 690 general geographic and stratigraphic distribution tabulated 106 type specimen figured PI. XV, fig. 7 inflaia, described 690 compared with Acrothyra minor 717 Obolus ( Westonia) ella 674 general geographic and stratigraphic distribution tabulated 106 type specimen figured PI. LXXVI, fig. 2 "inflata ovalis," discussed 691 Icutorgai, described 692 cardinal area discussed 305 compared with ^cro(/idf bellula 637 Acrotreta attenuata 675 Acrotreta concentrica 6S1 Acrotreta eggegrundensis 684 A crotreta sagittalis transversa 673 deltidium discussed 306 general geographic and stratigraphic distribution tab- ulated 106 type specimen figured PL LXV, fig. 3b lisani, described 692 general geographic and stratigraphic distribution tab- ulated 106 - type specimen figured PI. LXVIII, figs. 3, 3a-b marjumensis, described 693 cardinal area discussed l 305 general geographic and stratigraphic distribution tab- ulated - 106 type specimen figured PI. LXXVIII, fig. 2 microscopica, described 693 compared with Acrotreta microscopica missouriensis . . . 694 Acrotreta microscopica tetonensis 694 Acrotreta ovalis 699 Acrotreta schmalenseei 709 Acrotreta shantungensis 711 Acrotreta signalis 711 false area in, discussed 674 general geographic and stratigraphic distribution tab- ulated 106 type specimen not figured. 816 CAMBRIAN BRACHIOPODA. Acrotreta microscopka missourknsis, described 694 general geographic and stratigraphic distribution tab- ulated 106 tj-pe specimen figured PL LX VII, fig. 4 microscopka tetoncnsis, described 694 compared with Acrotreta microscopka iiiissourknsis. . . 694 general geographic and stratigi-aphic distribution tabulated. ." 106 t j-pe specimen figured Pi. LXVII, fig. 3 mini ma, described 695 general geographic and stratigraphic distribution tabulated 106 tj-pe specimen figured Pi. LXXVII, fig. 7 misera, described 695 compared with Acrotreta curvata 673 Acrotreta kutorgai 673 Acrotreta scUmalcTiseei 673 general geographic and stratigraphic distribution tabulated 106 tj'pe specimen not figured. neboensis, described 695 compared with Acrotreta marjumcTisis 693 general geographic and stratigraphic distribution tabulated 106 type specimen figured PI. LXXVII, fig. 9a nkliolsoni, described 696 cardinal area discussed 303 general geographic and stratigraphic distribution - tabulated 106 type specimen figured PI. LXXIII, fig. 1 " cf. niclwlsoni Matley," discussed 703 Twr, described 696 general geographic and stratigraphic distribution tabulated 106 tj'pe specimen figured PI. LXXVII, fig. 10 ulated 106 stratigraphic distribution mentioned 674 type specimen figured PL LXIX, fig. 2f "recurva," type species of Volborthia 366 rudis, described 702 general geographic and stratigraphic distribution tab- ulated 106 type specimen figured PL LXV, fig. 3f sabrinse, described 702 compared with Acrotreta bisecta : 679 Obolus ( JVestonia) ella 674 general geographic and stratigraphic distribution tabu- lated 106 type specimen figured PI. LXXIII, fig. 5b "sabrinas malvernensis,''' discussed 703 saggittalis, described 704 compared with A crotreta baileyi 677 A crotreta bellatula 678 Acrotreta belli 678 Acrotreta convexa 682 Acrotreta curvata 673 Acrotreta inflata 691 Acrotreta kutorgai 673 Acrotreta paclfica 700 Acrotreta cf. sagittalis 706 Acrotreta sagittalis magna 706 A crotreta sagittalis taconica 7Cf7 Acrotreta sagittalis transversa 708 Acrotreta schmalenseei 673 SchizophoUs ■. 609 general geographic and stratigraphic distribution tabu- lated 106 type specimen not figured. cf. sagittalis, described 706 general geographic and stratigraphic distribution tabu- lated 106 sagittalis magna, described 706 compared with A crotreta baileyi 677 A crotreta cf. socialis 712, 715 A crotreta sp. undt 715 discussed 687 general geographic and stratigraphic distribution tabu- lated 106 type specimen figured PL LXVI, fig. 4b sagittalis taconica, described 707 compared with Acrothele subsidua 633 Acrotreta baileyi 677 general geographic and stratigraphic distribution tabu- lated 106 type specimen figured PL LXXI, fig. Ic sagittalis transversa, described 70S compared with Acrotreta baileyi. 677 A crotreta curvata 673 A crotreta kutorgai 673 Acrotreta sagittalis magna 706 A crotreta schmalenseei 673 general geographic and stratigraphic distribution tabu- lated 106 type specimen not figured. schmalenseei, described 709 compared with Acrotreta ovalis 699 A crotreta sagittalis transversa 673 Acrotreta secbachi 710 A crotreta socialis 712 general geographic and stratigraphic distribution tabu- lated 106 type specimen figured ^ PL LXX, fig. la INDEX. 817 Acrotreta seebachi, described 710 compared with A crofrda carinata 6S0 Acrotreta circularis 680 general geographic and stratigraphic distribution tabu- lated 106 type specimen figured PI. LXXVII,fig, 3 sJiantungensis, described 710 general geographic and stratigraphic distribution tabu- lated 106 type specimen figured PI. LXIX, figs. 5, 5a-b sigTialis, described 711 general geographic and stratigraphic distribution tabu- lated 106 type specimen figured PI. LXIX, fig. 4 "sipo," discussed 679 socicUis, described 711 association mentioned 340 compared with Acrotreta carinata 6S0 Acrotreta schmalenseei 709 Acrotreta seebachi 710 Acrotreta sp. undt. 715 discussed 703 false area in, discussed 674 general geographic and stratigraphic distribution tabu- lated 106 type specimen figured PI. LXXIII, figs. 3 and 3a sodalis Gromvall, discussed 712 socialis Linnarsson, compared with Acrotreta socialis von Seebach 709 discussed 712 socialis von Seebach, compared with Acrotreta socialis Linn- arsson 709 cf. socialis Matley, discussed 703 cf. socialis Matthew, discussed 712 spinosa, described 713 general geographic and stratigraphic distribution tabu- lated 106 surface ornamentation discussed 302, 672 type specimen figured PI. LXXIX, fig. 4b suhconica, described 713 compared with Acrothele coriacea 642 Acrotreta gemma 685 Acrotreta schmalenseei 709 A crotreta socialis 712 false area in, discussed 674 general geographic and stratigraphic distribution tabu- lated 106 interior unknown 673 type of Acrotreta 673 type specimen figured PI. LXXIIf , figs. 2f and 2g ulrichi, described 714 general geographic and stratigraphic distribution tabu- lated 106 type specimen figured PI. LXXVIIT, fig. 3 uplandica, described 714 general geographic and stratigraphic distribution tabu- lated 106 type specimen figured PI. LXX, figs. 3, 3a-b uplandica limoensis, described 714 compared with A crotreta uplandica 715 general geographic and stratigraphic distribution tabu- , lated 106 type specimen figured PI. LXX, figs. 4, 4a-b sp. undt., described 715 discussed 712-713 general geographic and stratigraphic distribution tabu- lated 106 type specimen not figured. Sp. undt. Westerg^rd, described 715 general geographic and stratigraphic distribution tabu- lated 106 type specimen not figured. Acrotretacea, classification of 321. 324 distribution in Cambrian strata 316 genera and species referred to, described 630-721 Acrotretidse, classification of 321, 321 distribution in Cambrian strata 315, 316 genera and species referred to, described 630-721 62667°— VOL 51, PT 1—12 52 Acrotretidas — Continued . general stratigrapliic distribution and number of Cambrian genera and species of 112 number of Cambrian genera and species of 112 number of genera and species in monograph 113 number of Ordo^ician genera and species in monograph 113 Acrotretina?, classification of 321, 324 genera and species referred to described 665-721 acuminata, see Lin^ulella (Lingulepis), acuminata meeki, see Lingulella (Lingulepis). acumzTiata sequens, see Lingulella (Lingulepis). * acuminatus, see Obolus (Schmidtia), acutangula, see Lingulella. Adairsville, Georgia, locality at 96x Adams, Frank D., acknowledgments 12 Adams County, Wisconsin, localities in 99a, 328k Adams Hill, Eureka district, Nevada, localities at 62, 63 Addison County, Vermont, locality in 227 Adductor muscles, defined 292 Adrados, Spain, locality near 350 advenus, see Obolus. affinis, see Obolus (Lingulobolus). Agassiz, Alexander, acknowledgments 12 Age, characters of old age discussed 315 agnostorum, see Lingulella. Agnostus, association mentioned - 349,767 mentioned 501 fallax, association mentioned 531 gibbus, association mentioned 531 inter str ictus, association mentioned 658 iruyensis, association mentioned 499 Isevigatus, association mentioned 476, 700 Ixvigatus zone (Middle Cambrian), in generalized section for Sweden, Denmark, Finland, and Norway, listing species and localities 145 localities in 310q, 320b, 320r, 320u, 321p parvifrons zone (Middle Cambrian), in generalized section for Sweden, Denmark, Finland, and Norway, listing species and localities 146 locality in 334d punctuosus, association mentioned 498 A graulos socialis, association mentioned 498 agreste, see Eoorthis. Akarpsmolla, Sweden, locality at 309e Alabama, Cambrian species of, listed 114-119 generalized section of Cambrian in, listing included and cor- related species and locahties 147 localities in 16, 17b, 56c, 56o, 56q, 56u, 89, 90, 90a, 90b, 90c, 90x, 91, 92x, 93, 93a, 93n, 93o, 93x, 94, 94a, 94o, 94x, 94xx, 95a, 137, 138, 139, 139a, 140, 141, 142, 144c, 145, 146, 146f, 361 alabamaensis, see Micromiira. dlandensis, see Obolus (Westonia). Aland Island, Finland, localities on 3Ud-f, 311q-t, 311w-y alata, see Syntrophia. Albany, New York, locality near 72 Alberta, Cambrian species of, hsted 114-119 localities in 35d, 35e, 35g, 35h, 57c, 57d, 57g, 57k, 57s, 57y, 58f, 58i, 58t, 58w, 58z. 60b species and localities in, correlated with those of British Columbia 125-131 alberta, see Nisusia. Albertella helena, mentioned 641 Albertella helena fauna, mentioned 457 Alemtejo, Portugal, locality in 351 Alexandria Bay, New York, locality near 338j Allamakee County, Iowa, locality in 341 Allan, J. A., Upper Cambrian formations named by 125 work on Cambro-Ordovician boundary in British Columbia. 125 Allumette Island, St. Lawrence River, Canada, locality on 319p Alma, Wisconsin, locality at 328c Alpha Station, Nevada, locality near 313c alta, see Acrotreta idahoensis. Altenhof , Esthonia, Russia, locality at 337e Alum slate (Upper Cambrian), locality in ; 310s Alunbruk (alum works), Oeland Island, Sweden, localities at 309j, 309m, 32Dq, 321x, 390 Amargosa River, California, localities east :;i 141, 14n, 14o, 14p Amberson, Alabama, locality near- - 83a 818 CAMBRIAN BRACIIIOPODA. amhigua, see EJkania. Ami, Henrj" M., acknowledgments 12 bibliographic reference 13 species named for 731 amii, see Ni&usia (Jamesella). Amis post office, Tennessee, locality near 121a Aniour, see Point Amour. ample, see Lin-gulella. anceps, see Obolus. anciUus, see Obolus. Anderson County, Tennessee, localities in 7d, 374a Andrarum, Sweden, localities at 8w, 3101, 320c, 32Df, 3201, 320o, 320s, 321y, 390o Andrarum limestone (Middle Cambrian), in generalized section for Sweden, Denmark, Finland, and Norway, listing species and localities 145 localities in 320c,334b, 334e *' Annelid sandstone, " mentioned 539 anomala, see Wimanella. *'Anomites lenticularis," type of Orusia 765 A nopolenus, association mentioned 49S venustus, association mentioned 498 Anse au Loup, see L'Anse au Loup. Antelope Spring, House Range, Utah, localities near 3s, 3t, 3x, 3y, 4, 8g, 81, 8k. lie, lis, 30d, 31s, 31v Antelope Valley, Eureka District, Nevada, locality in 59 Anterior lateral (retractor) muscles, defined 292 shown in figure 374 Anterior region, defined 292 antiquata, see Swantonia. antiquissimus, see Obolus (Acntis). Aparchites? aTtderssoni, stratigraphic position of bowlder contain- ing, discussed . .-^ 454, 684 Apatocephalus zone (passage beds), in generalized section for Swe- den, Denmark, Finland, and Norway, listing species and localities 144 locality in 390e Apex, defined 292 Apical callosity, defined 292 apollinis, see Obolus. apollinis ingrkus, see Obolus. apollinis moximus, see Obohis. apollinis quenstedti, see Obolus. appalacJiia, see BilUngsella and Dicellomus. Appalachian province, Cambrian species in , listed 114-119 Arbuekle limestone (Upper Cambrian), detailed section, listing included and correlated species and localities 141-142 localities In 9z, 12j, 12ni Arbuekle Mountains, Oklahoma, detailed section of Cambrian and Ordovician in, listing species and localities 141-142 locality in 12p Archseocyathinse white limestone (Middle? Cambrian), locality in 315c A Tchseocijathus, association mentioned 584 Archangel Quarry, near St. Petersburg, Russia, locality at 336x Areola, Minnesota, locality at 339b Ardmillan Brae, Scotland, locality at 316a Ardmore quadrangle, Oklahoma, localities in 12h, 12in, 12n Ardrossan, Yorke Peninsula, South Australia, locality near 315a Area, defined 292 shown in figure 374 Arenig, in generalized section for England, Scotland, and Wales.. 135 Arenig, North Wales, locality in 305e Argenta, Big Cottonwood Canyon, Utah, locality near 30a argenta, see Acrotreta and Nisusia {Jamesella). Argentina, Cambrian species of, listed 122 localities in 389, 383a-d argia, see Syntrophia primordialis. arguta, see Lingulella. Argyle, see South Argyle. A Tioncllus, association mentioned 598, 600, 767 Arizona, Cambrian species of, listed 114-119 Dicellomus poUtus from, discussed 577 localities in.. 9o, 14x, 17c, 73, 73a, 73b, 74, 74b-d, 75, 358, 358a-b stratigraphic position of brachiopod localities in, discussed.. 124 Armstrong Creek, Tennessee, locality near Ha artemis, see A crothele. Articulata, distribution in Cambrian strata 316 shell structure of 296 Articulate brachiopods, defined " 292 Articulating processes, discussed 307 " Asaphcllus fauna, " mentioned 679 AsaphellU'S zone, in generaUzed section for Cape Breton, listing in- cluded species and locahties 131 Asaphiscus tvhcckri, association mentioned 658 AsaphU:S broggcri zone, in generalized section for Russia 143 Asaphus cichwaldi zone, in generalized section for Russia 143 Asaphus eipansus zone, in generalized section for Russia 143 Asaphus lepiduTus zone, in generalized section for Russia 143 Asaphus raniceps zone (Ordovician), in generalized section for Russia 143 locality in 337j Ash Creek, Arizona, locality on 358a Asia, zoologic list of Cambrian species of, gi^'lng distribution by countries 121-122 asiatica, see Obolella. Asserien, Esthonia, Russia, localities at 395c, 395j, 395p, 395s Asterisks in localities, explanation of IGO afava, see Eoorthis and Lingulella. atava in^ulse, see Lingulella. Atherstone, England, locality in 304j atlantica, see Obolella. Atlantic coast province, Cambrian species in, listed 114-119 Atremata, cardinal area discussed 303-304 classification of 322 defined 292 derivation 327 distribution in Cambrian strata 316 evolution of genera of, discussed 31S-319 genera and species referred to, described 327-585 holoperipheral growth of pseudodeltidia in 306 muscle scars discussed 312 pedicle furrow discussed 314 surface ornamentation discussed 301 vascular markings discussed 311 afrypoides, see Orusia lenticularis . Attalla, Alabama, locality at 361 attenuata, see Acrotreta. aitenuata var. ?, see Acrotreta. Attleboro, see North Attleboro. auga, see Lingulella. '^ Aulonotreta polita," mentioned 383 aurora, see Obolus (^Westonia). Aurum, Schell Creek Range, Nevada, locality near 8o Ausable Chasm, New York, localities in 77, 338t Ausable River, New York, locality on 338s Australia, see South Australia. Austria-Hungary, see Bohemia. avia, see Acroihele. avia puteis, see Acrothele. '^Avicula desquamata," discussed 594 Ayrshire, Scotland, locality in 316a A , treated as A in this index . babel, see Acrotreta. baileyi, see Acrotreta. Bala, North Wales, localities near 366m, 366o Bala (Coniston) limestone (Upper Cambrian), in generalized sec- tion for England, Scotland, and Wales, listing species and localities 135 locality in 304n Bala Road, North Wales, localities on 305f, 366j Bala schists (Upper Cambrian), locality in 366o Balbriggan, Ii'eland, locality at 317a Balcletchie, Scotland, locality at 316a Bald Mountain, Bighorn Mountains, Wyoming, locality near 170 Bald Mountain, Washington County, New York, localities near. . 35, 35a, 338h, 338z Baldwin's ranch, Texas, locality at 14c Baltic region, localities in 395f , 396e, 396f , 396o See also Esthonia, Finland, Swedfen, etc. balticus, see Obolus ( Wcstonia). Baltischport, Esthonia, Russia, localities at 336h, 336111, 336r, 337i, 3371, 395x, 396, 396x Baltischport Peninsula, Esthonia, Russia, localities on 396a, 396n "Bandede Jinec" (Middle Cambrian), locality in 345b Bangor, North Wales, locality in 366d Baraboo, Wisconsin, localities near lOv, 116 Baraboo quadrangle, Wisconsin, localities in lOv, 116 INDEX. 819 barahuensis, see SyntropMa. Barachois, Nova Scotia, localities at 3o, lOo, 372c Barachois Glen, Nova Scotia, localities in 3q, lOn Baracliols River ( = McLeod Brook), Nova Scotia, localities on ...lOc-l, lOk-m, 13h, 307, 307a, 307h, 372e Bar Creek, Montana, localities near 3j, 5j Barn Bluff, Minnesota, locality at 113 Bamet quadrangle, Texas, localities in 14e, 14q Barrande, J. , bibliographic references 13 species named for 603 Barrande, J., [de Vemeuil, E. P., and] bibliograpliic reference 24 barraiidei, see Botsfordia. Barrel Spring, Nevada, localities near 11, Im, Ip, Iv Barrel Spring section, in detail, listing included and correlated species and localities 137-138 Barrois, Charles, acknowledgments 12 bibliographic reference 13 Bartlett Hollow, Texas, localities in 14e, 14q Baitow County, Georgia, localities in 59m, 96x, 362 "Basal series" of Matthew (Lower Cambrian), locality in 301v Bass Canyon, Arizona, locality in 74d Bassler, R. S., acknowledgments 13 bibliographic reference 13 work on microscopic structure of Brachiopoda 297 Bastard township, Ontario, localities in 392b, 392e Bathyurus, association mentioned 493 Bavaria, Cambrian species of, listed 120-121 locahties in 303c, 303f bavaricj, see Eoorthis. havaricus, see Obolus. Bays Mountains, Tennessee, localities in 10a, 10b, 106, 106a Bear Creek, Montana, localities on 160a, 340f Bear Gulch Valley, South Dakota, locality in 355a Bear Lake County, Idaho, localities in 55c, 56f, 56g, 59f, 59g, 163, 322, 322a Bear River Canyon, Wyoming, locality in 340d Beauhamois, Quebec , locality near 319u Beauhamois Canal, Quebec, locality on 319t Beaver County, Utah, localities in 34r, 34t Beaver Creek, Montana, locality on 9h Beaver Creek, Wisconsin, locality on 79x Beaver limestone, in generalized section for Tennessee, Georgia, and Alabama 147 Beaver Mountains, see Cricket Range. Beaver River Range, see Cricket Range. Beecher, C. E., bibliographic reference 13 Rustella compared with '^ Paterina" of 328 Beekmanto\vn limestone. Division A (Ordovieian), locality in 367c mentioned _ 551 Bell, A., species named for 386 bella, see Liiiguldla and Micromitra (Paterina). bellapunctata, see Acrothdc. bellatula, see Acrotrcta. Belleisle, see Straits of Belleisle. Bellewstown, Ireland, locality at 317a belli, see Obolus. bellula, see Acrothele and Lingulella. beUulus,see Obolus (Fordinia). Belschwitz, East Prussia, locality near 386 belli, see Acrotrcta. Belt Mountains, see Big and Little Belt Mountains. Belt Park, Montana, locality in 4x Beman Park, Troy, New York, locality at 2d Bennett's Spring, Nevada, locality near 30 Beraun, Bohemia, locality near 303p Bergen Park, Colorado, locality near 360a Bergeron, J. , species named for 638 bergeroni, see Acrothele. Berlin, Wisconsin, locality at 328d Bessemer, Alabama, locality at 56u See also South Bessemer. Bethany Chapel, Tennessee, locality near 2z Beverly, Ontario, Lingulella (Lingulepis) acuminata at, dis- cussed 547_54S locality at 39213 Bibb County, Alabama, localities in 90b 90c Bibliography ^^ Bic, Quebec, localities at 2o, 2p 2r Bicia, described 568 articulating processes discussed 307 cardinal area discussed 304 classification of 321, 323 compared with Linnarssonclla 665 Trematobolus kcmpanum 620 evolution discussed 318 evolution of 317 general geographic and stratigraphic distribution of the species referred to 103 general stratigraphic distribution and number of Cam- brian species and varieties of 110 muscle scars discussed 312 number of species of, in d iff erent types of sediment . . . 160 stratigraphic position mentioned 318 type species "Oholella gemma'' 569 vascular markings discussed 311 gemma, described 569 compared with Bicia whiteavesi 568, 569, 571 Obolella 588 Obolella? lindsiromi 596 Obolella mobergi 597 Obolella ( Glyptias) favosa 600 Trematobolus 615 discussed 568,569 general geographic and stratigraphic distribution tab- ulated 103 surface ornamentation discussed 302 type specimen not figured. whiteavesi, described 570 compared with Bicia gemma 568, 569 Pholidops impUcata 56S discussed 568, 569 general geographic and stratigraphic distribution tab- ulated , 103 type specimen figured PI. L, fig. 2c Biciinse, classification of 321, 323 genera and species referred to, described 568-573 Big Belt Mountains, Montana, locality in 9h Big Cottonwood Canyon, Utah, localities in 30a, 33i, 55u Big Creek, Tennessee, localities on 123, 124, 124a Big Goose Creek Canyon, Wyoming, localities in 171, 171a Bighorn Mountains, Wyoming, localities in I4k, 168, 170, 171, 171a, 302m, 302u, 302x, 302y Big Ridge, Cape Breton, locality on ilz Big River, Missouri, locality on 369e Bigsby, J. J., bibliographic reference 14 Billingen, Sweden, localities at and near 309c, 390k See also Mount Billingen. Billings, E., bibliographic references 14 genera named for 562, 750 species named for 483,740,806 Billingsella, described 749 articulating processes discussed 307 cardinal area discussed 304, 305 cardinal process discussed 306 classification of 32I, 325 compared with J?oortft25 755,772,773 Finkelnburgia osceola 795 Nisusia 306, 725, 726 Orthis 772, 773 Plectorthis whitfieldi by Ulrich 308 Wiwanella 745 Wynnia 771 cruralium discussed 309 deltidium discussed 306 evolution discussed 319, 320 evolution of 317 general geographic and stratigraphic distribution of the species referred to 107-108 general stratigraphic distribution and number of Cambrian species and varieties of ill mentioned 492 muscle scars discussed 313 number of Ordovieian species and varieties of 113 number of species of, in different types of sediment. . . 160 pedicle tube discussed 315 pseudodeltidiura discussed 313 pseudospondylium discussed 307 820 CMIBRIAN BRACHIOPODA. Bi Hi njseZZa— Continued. reference to, of Otii>sia san^bergi discussed 770 reference to, of Synlrophia uniia discnssed 805 reference to, of ^VilnantUa anomala discussed 746 stratifiraphic position mentioned 3 IS tn^e species '^ Orthis coloradocnsis" 749 Ulrich on spondylium 308 vascular markings discussed 311 fappalachia, described 750 compared with Wimanella shelbjfcnsis 747, 748 general geographic and stratigraphic distribution tabulated 107 type specimen figured PI. LXXXVII, fig. 2a bivia, described 750 general geographic and stratigraphic distribution tab- ulated 107 type specimen figured text fig. 65 A, 750 coloradocnsis, described 751 compared with Billingsella highlaridensis 756,757 BillingscUa I'mdstromi 757 BilUngscUa major 758 BilUngscUa obscura 758 BilUngscUa orientalis 759 BilUngscUa pUcatella 745,760 BiUingscUa pumpcUyi 761 BiUingscUa rctroflexa 761 Eoorthis joTtanneiisis 781 WiviancUa harlanensis 745, 746 WimaneUa simplex 748 deltidium discussed 306 general geographic and stratigraphic distribution tab- ulated 107 pedicle opening in 749, 751 shell section figured textfig. 5, 299 type specimen not figured. dicej described 754 discussed 750 general geographic and stratigraphic distribution tab- ulated 107 type specimen figured PI. CI, fig. 8 exporrccta, described 754 compared with BiUingseUa exporrecta rugosicostata 755 BUUn^sella Mcksi 756 Eoorthis Unnarssoni 783 WimaneUa harlancTisis 746 discussed 750 general geographic and stratigraphic distribution tab- ulated '107 intermediate 'hetv/een BiUingseUa and EooUliis 755 tj'pe specimen not figured. vascular markings discussed 311 exporrecta rugosicostata, described 755 general geographic and stratigraphic distribution tab- ulated 107 type specimen figured PI. LXXXVIII, fig. 2 Mcksi, described 756 compared with Eoorthis UnTiarssoni 783 general geographic and stratigraphic distribution tab- ulated 107 type specimen figured PI. XCVII, figs. 7 and 7a liighlandensis, described 756 compared with B iUingseUa bivia 750 BiUingseUa pUcatcUa 745 WimaneUa simplex 748 general geographic and stratigraphic distribution tab- ulated 108 pseudospondylium discussed 307 type specimen figured PI. LXXXVII, fig. 4b lindstromi, described j 757 general geographic and stratigraphic distribution tab- ulated 108 type specimen not figured. major, described 758 compared with BiUingseUa coloradocnsis 752 general geographic and stratigraphic distribution tab- ulated 108 type specimen figured PI. LXXXVI, fig. la marion, described 758 general geographic and stratigraphic distribution tabulated 108 type specimen figured text fig. 67A, 758 BillingscUa obscura, described 758 general geographic and stratigraphic distribution tabulated 108 tj'pe specimen figured Fl. LXXXVI, fig. 6 orientalis, described 759 compared with Eoorthis johanncnsis 781 general geographic and stratigraphic distribution tabulated 108 pseudospondylium discussed 307 type specimen figured Pi. LXXXVI, fig. 2 pUcatella, described 759 compared with Billingsella coloradoensis 745, 752 Billingsella Mghlandensis 745 Billingsella striata 764 Hucnella abnormis 806 Wimanella harlanensis 745, 746 general geographic and stratigraphic distribution tabulated 108 intermediate between Billingsella coloradoensis and Wimanella harlanensis 745 shell section figured text fig. 1, 299 type specimen figured PI. LXXXVI, fig. 3i vascular markings discussed 311 jmmpeXlyi, described 760 compared with Billingsella rctroflexa 762 general geographic and stratigraphic distribution tabulated 108 type specimen figured PI. XCVII, fig. 8 retroflexa, described 761 general geographic and stratigraphic distribution tabulated 108 type specimen figured PI. XC, fig. Ih richthofeni, described 761 general geographic and stratigraphic distribution tabulated 108 type specimen figured PI. LXXXIX, fig. 1 romingeri, described 762 compared with BiUingseUa dice 754 Billingsella pumpellyi 761 Billingsella rctroflexa 761 Nisusia ? vaticina 730 Nisusia (Jamesella) Kuthani 733 Ortliis tricenaria by Ulrich 308 "Orthis sp. Pompeckj " 793 Wynnia warthi 771 general geographic and stratigraphic distribution tabulated 108 type specimen figured PI. XC, figs. 2, 2a-d salemensis, described 763 compared with Billingsella coloradoensis 752 Billingsella marion 758 Billingsella whitfieldi 764 general geographic and stratigraphic distribution tabulated 108 type specimen figured PI. LXXXVII, fig. 3 striata, described 764 compared mth BiUingseUa pUcatella 760 general geographic and stratigrapliic distribution tab- ulated 108 type specimen figured PI. LXXXVI, fig. 4 whitfieldi, described '. 764 compared with Billingsella salemensis 763 general geographic and stratigraphic distribution tab- ulated 108 type specimeh figured PI. LXXXVI, fig. 5a Bilhngsellidse, classification of 321, 325 compared with Ordo\acian Ortliida^ 320 OrthidEE, by Ulrich 308 distribution in Cambrian strata 315,316 genera and species referred to, described 725-795 general stratigrapliic distribution and number of Cambrian genera and species of 112 number of Cambrian genera and species of 112 number of genera and species in monograph 113 number of Ordo\acian genera and species in monograph 113 shell structure compared mth that of Orthidse 300 shell structure of 300 Billingsellidtc (Cambrian), shell structure compared with that of Ordovician Protremata 300 INDEX. 821 BillingselliHEe, classification of 321, 325 genera and species referred to, described 745-772 surface ornamentation discussed 303 billingsi, see HucncUa and Protorthis. billingsiana, see Lingulclla, BillstaAn River, Sweden, locality on. 320t Billy Creek, Wyoming, locality on 302m Bilobites, classification of, by Ulrich 308 muscle scars of, discussed by Ulrich 308 no Cambrian representatives 320 Biludden, Sweden, localities on the peninsula of 3Ub, 311c, 311g-l, 321e-ni Birch Point, Newfoundland, locality near 6y Birmingham, Alabama, locality near 56q Bisbee, Arizona, localities near 14x, 358b hisccta, see AcTOfrcta. Bishops Mill, Tennessee, locality at 105 bivia, see BiUingscUa. Bjorkelunda, Sweden, localities at 321u, 321v Black Hills, South Dakota, localities in 17j, 17k, 88a, 164, 165, 167, 355, 355a-f Black Mountain, see Montagne Noire. Blackrock, Utah, locality near 33r "Black shales" (Upper Cambrian), localities in 304b, 304e, 304f mentioned 557, 559 Blacksmith Fork Canyon, Utah, localities in 31c-e, 31h, 311-n, 54a-p, 54y, 55h, 55n, 185z Blacksmith Fork section, Utah, in detail, listing included and correlated species and localities 148-153 Blacksmith limestone, in detailed section in Blacksmith Fork, Utah, listing included and correlated species and localities 150 Blaclcwelder, Eliot, acknowledgments 12 bibliographic references 14 species named for 453 Blackwelder, Eliot [Willis, Bailey, and], bibliographic reference.. 26 Nackwelderi, see Obolus ( Westonia), Bland County, Virginia, locality in 47h Blochmann, Fr., bibliographic reference 14 terminology of 292 Bloomington formation (Middle Cambrian), in detailed section in Blacksmith Fork, Utah, listing included and correlated species and localities 149-150 localities in 5h?, 3ih, 31 1, 32x?, 54h, 541, 54k, 54v, 55dT, 55n Blount County, Alabama, localities in 16, 89, 144c Blountsville Valley, Alabama, locality in 16 Blue clay, in generalized section for Russia 144 Boda, Sweden, locality at 9e Bohemia, Cambrian species of, listed 120-121 generalized section of Cambrian and Ordovician in, listing species and localities 124 localities in 303, 303a, 303b, 303d, 303e, 303g-p, 345, 345a-l species of Obolus from, listed 379 bdhemica, see Acrothele. Boisdale, Cape Breton, localities near 3p, lOe-l, 13h, I60, 307a, 372b Boisdale Road, Cape Breton, localities near lOd, lOi, 10k, 10m, 372a Bonar, Spain, locality near 350 Bonne Bay, Newfoundland, locality at 314f Bonneterre, Missouri, localities at and near 369a, 369c, 369g Bonneterre limestone (Middle Cambrian), in generalized section for Missouri, listing species and localities 137 localities in Hj^ Hm Borgholm, Sweden, localities at 8z' 309f, 310b, 310d, 3101, 310j, 310o. 310p, 320g, 390i horgholmen^is, see AcrotTiele. Bomemann, J. G., bibliographic reference 14 species named for 484 bornemanni, see Lingulclla. Bornholm Island, Denmark, localities on 16h-l, 334, 334a-li Borregaard, Denmark, localities at 16h, 16i, 161, 334a-d, 334h Borstil, Sweden, localities in Slip, 311v, 321, 321a-d, 321o Borthwood, Wales, locality at 305h Bostwick Canyon, Montana, locality in 148a Bosworth, see Mount Bosworth. ' Bosworth formation, detailed section listing correlated species and locaUties 126 resemblance to Algonkian Belt series mentioned 126 Botsfordia, described gOl classification of 321 324 compared with A crothele (RedUchella) 663 Dicellomus 572 Bois/ordia — Continued. compared with Obolella 5S7, 58S YoTkia ? ivashingtonensis 613 evolution discussed 319 evolution of 317 general geographic and stratigraphic distribution of the species referred to 104 general stratigraphic distribution and number of Cam- brian species and varieties of 110 mentioned . . .' 605 muscle scars discussed 312 number of species of, in different types of sediment. . 160 pedicle tube discussed 314 reference to, of Botsfordia barrandci discussed 603 surface ornamentation discussed 301, 302 type species Obolus pulcher 601 vascular markings discussed 311 ? barrandci, described 602 discussed 633 general geographic and stratigraphic distribution tabu- lated 104 surface ornamentation discussed 302 type specimen figured PI. LVII, fig. 7 cselata, described 603 cardinal area discussed 305 compared with A crothele matthewi 632 Acrothele nitida 650 Botsfordia pulchra 608 Obolus clcgans 391 Sckizopholis rugosa 609 general geographic and stratigraphic distribution tabu- lated 104 stratigraphic position mentioned 318 sm-face ornamentation discussed 301, 302 type specimen not figured. granulata, described 605 cardinal area discussed 30^ compared with Acrothele matthewi 632 Acrothele (Eedlichella) , 663 Acrothele (Redlichella) granulata 602, 663 Botsfordia cxlata 604 Botsfordia pulchra 601, 60S discussed 601 general geographic and stratigraphic distribution tabu- lated .^. 104 surface ornamentation discussed 302 type specimen not figured. pulchra, described 607 cardinal area discussed 305 compared with A crothele bellapunctata 633 Botsfordia ? harrandei 603 Botsfordia cxlata : . . . 606 Botsfordia granulata 601, 606, 607 Lingulella radula 529 Micromitra (Iphidella) pannula 602 discussed 602 general geographic and stratigraphic distribution tabu- lated 104 muscle scars discussed 312 surface ornamentation discussed '. ' 302 type specimen not figured. bottnicus, see Obolus ( Westonia). Boundary Brook, Cape Breton, locality on 344e Bow River group, detailed section listing species and localities 130 Boxelder County, Utah, localities in 30u, 31y, 32c, 32n, 32p, 32x, 32y, 33j, 33t, 34m, 34q, 54k, 54q. 54r, 55e, 105x, 329 Bozeman, Montana, locality near 160a Brachia, defined 292 Brachioccele, defined 292 shown in figure 374 vessels of, shown in figure 374 Brachiopod, most primitive 316, 318 oldest known 316 sunplest form 327, 328 Brachiopoda, bibliography 13-26 classification 321-326 definitions 292-296 distribution in Cambrian strata 315-316 distribution tables 9S-159 822 CAMBRIAN BRACHIOPODA. Brachiopoda— Continued . evolution 316-320 habitat 1 59-160 localities 161-291 number of genera in divisions of Cambrian 310 percentage of genera and species included in Obolidse, Acro- tretidte, and Billingsellidse 315 setfe of, figured 302 shell structure 296-300 structural features 300-320 summary tables 110-113 sjTionymy table 27-98 terminology 291-290 Braintree, Massachusetts, locality at 5 Braintree slate (Middle Cambrian), locality in 326b ^'Brandschiefer" (Ordovician), in generalized section for Russia, listing species and localities 1^3 locality in 337d Brantevik, Sweden, locality at 310z Bras d'Or Lake, Cape Breton, localities near lOo, lOr, 131, 13r, 307j, 325, 325b, 325c, 372d Brecknockshire, Wales, locality in 366r bretonensis, see Obolus (Palieobolus). brelonensis lens, see Obolus (Palieobolus). "Bretonian" (Upper Cambrian), generalized section of, listing species and localities 131 locality in 13<1 See also Divisions C2 and C3. Briceville quadrangle, Tennessee, locality in 7d Bridget Range, Montana, localities in 147a, U8a, 151, 151a, 152 Brigham, Utah, localities north and east of 31y, 32c, 32ii, 32p, 32x, 32y, 33j, 33t, 34m, 34q, 54k, 54q, 54t, 55e, lD5x, 329 Brigham quartzite, in detailed section in Blacksmith Fork, Utah, listing included and correlated species and localities 152-153 line between Lower and Middle Cambrian in .■ 153 Bristol, Tennessee, locality near '. 2z( Bristol County, Massachusetts, localities in 326a, 326d Bristol quadrangle, Tennessee, localities in 2z', 374c British Columbia, Cambrian species of, listed 114-119 detailed section for, with included and correlated species and localities ■125-131 localities in 14s, 35c, 35f, 35g, 35h, 35k, 57c-g, 57j, 57k, 57m, 57n, 57r, 57s, 57y, 58f, 58j- 1, 58p, 58r, 58s, 58z, 60b, 306 Mount Bosworth section, in detail, with included and cor- related species and localities 125-131 Brogger, W. C, acknowledgments 12 bibliographic references 14 (Broggeria'), see Obolus (BToggeria). Bronsil shales (Upper Cam.brian), in generalized section for Eng- land, Scotland, and Wales, listing species and localities.. . 135 localities in 304, 304a Brown's quarry, Prairie du Sac, Wisconsin, locality at 86a Bruachaig River, Scotland, locality on 316c Brunswick, New York, locality near 2d Bryn Melyn, North Wales, locality at 366o Brijograplus slate (Upper Cambrian), in generalized section for Sweden, Denmark, Finland, and Norway, listing species and localities 145 locality in 309a systematic reference discussed 98 Buch, C. L. von, bibliographic references 14 Buchava quarry, near Skrej , Bohemia, locality at 345d buchi, see Eeysirlingia. Buck Creek, Alabama, locality near 56c Buckingham Ford on HoUis Creek, Tennessee, locality at 117c Buffalo County, Wisconsin, locality in 328c Buffalo Creek, Montana, locality near 302f Buffalo Creek, Virginia, locality on 92b Buffalo Fork Peak, Wyoming, locality near 302v Buffalo Mills, Virginia, locality near 92b Builth, Wales, locality near 366r Bull Hill Cottage, South Shropshire, England, locality at 304k Bull Run, Tennessee, localities in 107, 107a, 107b BuUwhacker mme. Eureka district, Nevada, locality near 64 Bunker Hill, Tennessee, locality on 12q Burgess, Canada, locality at 392 Burgess Pass, British Coltmibia, locality near 36k B iirgess shale, mentioned 127 Burgess shale member of the Stephen formation (Middle Cam- brian), locality in 35k Burling, Lancaster D., acknowledgments 13 work on Cambro-Ordovician boundary in British Columbia. 125 Burling, Mrs. Lancaster D. , species named fo" 758 Burnet, Texas, localities near 67, 67c, 67z Burnet County, Texas, localities in 67, 67c, 67z, 69, 70, 70a, 70e, 71, 353a Biu'r, H. T., bibliographic reference 15 Butts, Charles, species named for 484 buttsi, see LingulcUa. Caballos Mountains, New Mexico, localities in 327, 327a-c Cable Mountain, Montana, locality on 340e Cabo Busto stage (Ordovician), localities in 350a, 350b Cache County, Utah, localities in 31c-e, 31h, 311-n, 31z, 32d, 32e, 54a-p, 54y, 55h, 65n, 55t, 185z, 329a csdaia, see Botsfordia. Caer-fai, Wales, locality at 366c Caerfai group (Middle Cambrian), in generahzed section for Eng- land, Scotland, and Wales, hsting species and localities . . . 136 localities in 318i, 366c Cahn Burn, Scotland, locality at 316b calcifera, see Sgntrophia. "Calciferous sandrock" (Lower Ordovician), Lingulella (Lingu- lepis) acuminata in, discussed 547 localities in 319t, 319u, 338u mentioned 509 "Calciferous sandstone," mentioned 551 Caledonia, Missouri, locality near 369d California, Cambrian species of, listed 114-119 localities in 7, 8b, 14 1, Itn-p, 53, 176, 176a, 178a, 312, 312a species and localities correlated ivith those of Nevada 137-138 Callaway, C, bibliograpluc references 15 Calls Fort, Utah, locality near 329 Camarella, compared with Swantonia 797 "caZcz/cra," compared with Clarkclla montancnsis 810 compared mth Stricklandinia 798 mentioned 798 volbortM , compared with Swantonia antiquata 797 Cambria, see Schucheftina and Syntrophia. Cambrian, number of genera in divisions of 316 sedimentation in Cordilleran region mentioned 148 species of Asia, zoologic Ust of, gi^nng distribution by coun- tries 121-122 species of Europe, zoologic Ust of, gi\'lng distribution by countries ,- 120-121 species of North America, zoologic Ust of, giving geographic distribution by States and geologic pro\'inces 114-119 See also Lower, Middle, and Upper Cambrian, and Passage beds. Cambridge, New York, localities near 36, 338x Cambridge quadrangle. New York, localities in 21 33, 33b, 36, 36b, 37, 37b, 39a, 43, 43a, 45a, 338c-g, 338i, 3381,338o,338p, 338x Camerella, mentioned 802 "aniiqua," type of Swantonia 797 "sp. Shumard" discussed 808 Camlan, North Wales, locality at 318e Campbell, M. R., bibUographio reference 15 species named for 802 campbdli, see Syntrophia. Camp Creek Canyon, see Queens Canyon. Canada, sec Alberta, British Columbia, Labrador, Ontario. Que- bec, Nev^ Brunswick, Newfoundland, Nova Scotia, and Cape Breton. Canadian Pacific Railway, Canada, localities on line of 14s, 36c-h, 35k, 57c-g, 57j, 57k, 57m, 67n, 57r, 57s, 57y, 58f, 581-1, 68p, 58r-t, 58w, 58z, 60b Canal Grande, Sardinia, localities at 354. 354c, 3548. 354f cancellata, see Acrotrem. Cane Creek Mountains, .Alabama, locality in 137 Cane Pass, Utah, localities at 34r. 34t ccmia, see Lingulella. Canon Ferry, Montana, locality near St Cantabrian Mountains, Spain, locality in 350 Canyon quadrangle. Wyoming, locality in 4j Canyon Range, Utah, locality in 33 INDEX. 823 Cape Breton, Caml^rian species of, listed 114-119 generalized section of Cambrian in, listing species and locali- ties 131-135 localities in 3h, 3i, 3n-q, 8d, lOc-i, lOk-p, lOp', lOp", lOq-t. llz, 13d, 13d', 13d", 13e-i, 13k, 131, 131'. 13m, 13n, 13n', I3n", 13p, 13p', 13q, 13r, 13t, 13t', 13t", 16o, 307, 307a-j, 325, 325a-c, 344, 344a-o, 372. 372a-f Cape Rouge, Quebec, locality at 319c Cape Vidio, Spain, locality at 350a Caradoc limestone, in generalized section for England, Scotland, and Wales, Usting species and localities 135 Carbon County, Wyoming, locality in 340c Cardinal area, defined -- 292 discussed 303-305 shown in figure 374 Cardinal extremities, defined 293 Cardinal muscle scar, defined 293 Cardinal Peat, Montana, localities near 4q, 4q', 8j Cardinal process, defined ■ 293 discussed 306 Cardinal scar, development of 312 Cardinal slopes, defined 293 Carillon, Quebec, locality near 392h carinata, see Acrotreta. Carlfors, Sweden, locality at 321p Carlton shore, New Brunswick, locality at 301t Carnarvonshire, North Wales, localities in 305a, 305c, 305d, 318a, 318b, 318s, 318t, 366d, 366e Camedd Flliast, North Wales, locality at 366d Carnegie Institution of Washington, acknowledgments 12 Carpenter, W. B., bibUographic reference «, 15 Carter County, Oklahoma, localities in 12k, 12m, 12n, 12p Cartersville, Georgia, locality near 96x Cartersville quadrangle, Georgia, locality in 96x Cascade County, Montana, localities in 4z, 5f, 5k Casper, Wyoming, locality near 302o Castle, Alberta, localities near 58i, 58t, 58w, 60b Castle Creek, South Dakota, locality on 355b Castle Mountain, Alberta, localities on 581, 58t, 58w Ogygopsis zone absent on 127 Cathedral limestone, detailed section 128-129 Catons Island, New Brunswick, localities on 2y, 301f, 308d " Causea," generic reference discussed ' 330 Cave Spring, Georgia, localities near 96b, 140a, 140c, 362a Cave Spring, Utah, locality near 15d Cedar BluS, Alabama, localities at 90a, 91 Cedartown Road, Georgia, locality on the 96 cedens, see Lingulella. Cefn Cyfarnedd, North Wales, locality at 305j celatuSf see Obolus (Schmidtia). Cement Creek, Colorado, localities on 335a, 360b Centennial Em'Cka mine, Tintic special quadrangle, Utah, locality near 34s Center, Alabama, localities near 90, 90x, 92x, 93, 93a, 93n, 93o, 93x, 94, 94a, 94o, 94x, 94xx, 95a, 146 Center road, Alabama, locality near the 95a Central (adductor) muscles, attachment In Orthidse 308 defined 293 shown in figure 374 ceratopygarum, see Acrothele. Ceratopyge limestone (Passage beds), Eoorthis dawnus characteris- tic of, to the exclusion of Eoorthis christianise 775 in generalized section for Sweden, Denmark, Finland, and Norway, listing species and localities 144 localities in 8x, 309, 310, 310j, 310x, 320w, 323, 323e-h, 323j, 323z, 386, 390, 390e, 390f mentioned 424, 515, 710, 712, 741 systemic reference discussed 98 "Orthis christianix" from, likely Eoorthis daunus 776 Ceratopyge hmestone and shale, Eoorfkis vyimani found in both . . . 775 Ceratopyge shale (Upper Cambrian), Eoorthis christianix character- istic of, to the exclusion of Eoorthis daunus 775 Ceratopyge slate (Upper Cambrian), in generalized section for Swe- den, Denmark, Finland, and Nor^vay, listing species and localities 145 localities in 310d, 310r, 310s, 321e-n, 323a, 323k, 323x, 323y, 390c, 3901, 395x? mentioned 424., 425, 710 systemic reference discussed 98 Cerro Cuchillo, New Mexico, locality near 327b Champlain, see Lake Champlain. Champlain Canal, New York, locality on 109 Changhia, China, localities at and near C17, C20, C22, C23, C26, C28, 036, C68 Changhia limestone (Middle Cambrian), localities in C22, 023, 026, 028 Chapman, E. J., bibliographic references 15 Chappie Arm, Newfoundland, localities on 6g, 6h, 314 Chappie Cove, Newfoundland, locality near 5t Chase Creek Canyon, Arizona, locality in 358 Chateaugay, New York, locality near Ill Chateaugay Falls, New York, locality at 338u Chatham, New York, locality near 32a Chatham, see North Chatham. Chaudiere River, Quebec, locality on 220a Chaumitien, China, localities at and near 036, 045, 068 Chaumitien limestone (Upper Cambrian), localities in 036, 045, 054, C56, 068 "Chazy formation" (Ordovician), localities in 319n-p, 392h Checker Beach, Rhode Island, locality on 343a Cheever's ranch, Wyoming, locality near 302u Ch61 Hill, Salt Range, India, localities at 357b, 357d Chepultepec, Alabama, localities near , 139a, 140 Cherokee, Texas, localities near 14g, 141 Cherokee County , Alabama, localit ies in 90, 90a, 90x, 91, 91x, 92x, 93, 93a, 93n, 93o, 93x, 94, 94a, 94o, 94x, 94xx, 95a, 146 Cherry Creek, Nevada, locality near 41 Cherry Creek Basin, Montana, locality near 149a Chilidium, defined 293 China, Cambrian species of, listed 121-122 localities in (Lower Cambrian) 03, 017, O20, 032' localities in (Middle Cambrian) 01, C2, C4-7, 09, CIO, 012, 022, 023, 024, 026, 028, 032, 037, 057, 062, 063, 070-72, 075 localities in (Upper Cambrian) 332, 332a, 036, 054, 056, 061, 064, CS7, 068, 074 species of Obolus from, listed 379 See Liaotung, Shansi, Shantung, and Shensi. chinensis, see Obolus. Chippewa County, Michigan, locality in 330 Chisago County, Minnesota, localities in 82b, 82c, 97b, 97s, 339d, 339j Chisholm mine, near Pioche, Nevada, localities at 7k, 31 Chonpinghien, China, localities near 032, 032' Chouteau County, Montana, locality in 302z Christiania, Norway, localities at and near 8x, 8z, 9f, 323, 323a, 323c-h, 323 1-q, 323t, 323V-Z christianise, see Eoorthis. Christianstad (province), Sweden, localities in 8w, SlOh, 3101, 320c, 320f, 3201, 320o, 320x, 321u, 321v, 321y, 390o chromatica, see Obolella. chuarensis, see Obolus {Westonia). Chuar Valley, Arizona, locality in 73a Chudleigh, Esthonia, Russia, locality at 337g Churn Canyon, Montana, locaUties near 151, 151a, 152 cincta, see Lingula. cingulata,see Kutorgina. circe, see Quebecia. circularis, see Acrotreta. Circulatory system, discussed 311-312 Clark, W. B., and Mathews, E. B., bibliographic reference 15 Clarke, J. M., acknowledgments 12 bibliographic references 15, 441 genus named for 809 species named for 486 Clarke, J. M., [Hall, J., and], bibhographic references 18 clarkci, see Lingulella. Clarkella, described 809 classification of 321, 326 cruralium mentioned 309 evolution discussed 320 evolution of 317 general geographic and stratigraphic distribution of the species referred to 109 numberof Ordovician species and varieties of 113 number of species of, in different types of sediment 160 spondy hum discussed 307 type species '^Polytcechia montancnsis" 809 Ulrich on spondylium 308 824 CAMBRIAN BRACHIOPODA. ClarkeUa montancnsis, described SIO general geographic and stratigrapliic distribution tabulated 109 tj-pe specimen figured PI. CIV, fig. 2a clarki, see Dcarbornia. Classification, importance of shell substance in 297 importance of surface ornamentation in 301 Clayton Coimty, Iowa, locality in 341a claytoni, see Acrotrcta. Clayton Valley, Nevada, locality near 175 Cleveland, Tennessee, locality near 128 Clifi House, Devils Lake, Wisconsin, locality near 81o Clifton quadrangle, Arizona, locality in 9o, 358 Clinton, Tennessee, locality near 7d Cliothijris, cardinal process discussed 306 CZi(am6oni/cs, compared with" Or(/jis pcpina" 739 compared with Protortkis 739 pedicle tube discussed 315 pseudospondylium discussed 307 Uirich on spondylium 308 Clitambonitidae, compared with Cambrian Orthidfe by Uirich.. 30S Uirich on spondylium 308 Coal Creek, Tennessee, locality near 374a Coal Hill, England, locality at 304e Coal Pit Bay, Ireland, locality at 317 Cochise County, Arizona, localities in - 14x, 358b Codorus Creek, Pennsylvania, locality on 49 Cog Hill, Tennessee, locality near 128a Cohoes quadrangle, New York, localities in 27a, 367b Coldbrook, New Brunswick, locality at 301c Coldbrook (Middle Cambrian), detailed section of, listing included species and localities 135 localities in 13k, 344f Cold Creek, Texas, localities on 14b, 14c, 71 Coleoloides cf. typicalis, association mentioned 328 Collen, M., species named for 641 colleni, see Acrothele. colUcia, see LiJigulella. Colorado, Cambrian species of, listed 114-119 locahties in 3g, 186, 186a, 187, 335a, 360, 360a-i note on stratigraphic position of localities in 135 coloTodoens^is, see Billingsella. Colorado River, Arizona, localities on 17c, 73, 73a, 73b, 74, 74b, 74c. 74d, 75 Colorado River, Texas, locality on 14r Colorado Springs, Colorado, localities near 360, 360d Columbia County, New York, localities in 29, 32a, 44b, 338b Columbia County, Wisconsin, localities in 86, 3281, 328e Columbiana, see Phillicdra. Comanche County, Oklahoma, localities in 9p-x, 9z, 12j Combs Peak, Eureka District, Nevada, locality on 59 Comley, in generalized section for England, Scotland, and Wales, listing species and localities 136 compleius, see Obolus. compta, see Nisusia. Conasauga limestone (Middle Cambrian), localities in 56o, 56q, 56u, 90b, 90c Conasauga (Coosa) shale (Middle Cambrian), in generalized sec- tion for Tennessee, Georgia, and Alabama, listing spe- cies and localities 147 localities in 16,90, 90x, 91, 92s, 94a, 146 mentioned 505, 521 coTicentrica, see AcrotTCta. Conception Bay, Newfoimdland, localities on 1, la, 2, 2a, 3, 5p, 5r, 5t, 61, 6ii, 6r, 6u, 6v, 41, 41a, 114, 114a, 114b, 314a, 314e, 314h section near, listing species and localities 140-141 Conchidium, cruraliiim mentioned 309 CoTHchidium nijsius. compared with. BilUngscUa exporrecta 755 concinna, see Linguldla. Coniston, England, locality at 304n Coniston (Bala) limestone (Upper Cambrian), in generalized sec- tion for England, Scotland, and Wales, listing species and localities 135 locaUty in 304ii Conococheague limestone (Upper Cambrian), locality in 346b ConocoTijphe elegans, association mentioned 498 CoTWCOTyphe exsulans zone (Middle Cambrian), in generalized sec- tion for Sweden, Denmark, Finland, and Norway, listing species and locaJjties 146 Conocoryphc exsulans zone — Continued. localities in „ 16i, 334a See also Exsulans limestone. ConocoTyphc trillncata, association mentioned 605 Conrad, T. A., bibliographic reference 15 conlraria, see Orbiculoidca. conula, see Acrotrcta. convexa, see Acrotrcta and Lingulella ivinona. Coopers Lake quadrangle, Montana, localities in 3 j , 5j Coosa River Valley, Alabama, localities in 90x, 92x, 94a, 145 Coosa shale, see Conasauga (Coosa) shale. Copenhagen, see Geneva. CopperRidge, Tennessee, localities on 107, 107a, 107b, 107o, 107u coriacca, see Acrothele. Coronado quartzite, localities above 9o, 358 Coronatus zone (Middle Cambrian), in generalized section for Sweden, Denmark, Finland, and Norway, listing species and localities 145 localities in 320i-k corrugata, see Finkelnburgia osceola. costata. see Acrothele prima, Cottonwood Canyon, Montana, locality near 152 See also Big Cottonwood Canyon. Coulouma, France, localities in 342, 342a Cound-Moor quarry, England, locality near 3041 Courtney Bay, New Brxmswick, locality on 301y Cowan Creek, Alabama, localities on. 93,93o, 93x, 94, 94a, 94o, 94x, 94xx, 95a Cow Head, Newfoundland, locality at 314c Coxsackie quadrangle. New York, locality in 338 Craighead, Scotland, locality at 316a Craigs Mountain, Alabama, locality near 90 Craig-y-dinas, North Wales, locality at 305 Crane, Agnes, bibhographie reference ' 15 Crania Isdia, compared with PMlhedra columbiana 724 " Crania unguiculata,' ' type of Siphonotreta 625 Craniacea, classification of 321, 325 distribution in Cambrian strata 316 genera and species referred to, described 724 Craniida^, canal system mentioned 312 classification of 321, 325 distribution in Cambrian strata 316 genera and species referred to, described " 724 general stratigraphic distribution and number of Cam.brian genera and species of 112 number of Cambrian genera and species of 112 number of genera and species in monograph 113 crassa, see Obolella. crassa elongata, see Obolella. crassus, see Obolus {Sclimidtia). crenistria, see Micromitra (Patcrina). Crepicephalus tcxanus , association mentioned 692 Cressage, England, locality at 3041 Crested Butte, Colorado, localities near 335a, 360b, 360c Criccieth, North Wales, locahty at 318a Cricket Range, Utah, locality in 33r Cricket Spring, Cricket Range, Utah, locality near 33r Crow Creek, Utah, locality on 33a Crowfoot Ridge, Gallatin quadrangle, Wyoming, locality on. 302b, 302g' Crura , defined 293 Cruralium, defined 293 discussed 309 Cruziana, association mentioned 359 Ctcnocephalus mattJiewi, association mentioned 498 . Cumberland County, Pennsylvania, locality in 49f Cumings, E. R., bibliographic reference 15 cuneola, see Lingulella. Curramulka, Yorke Peninsula, South Australia, locality at 315 Curtice, Cooper, genus named for 3b9 Curticia, described 369 classification of 321, 322 compared "with Diccllomus 360 Micromitra 318 Obolus 318, 369, 370 Rustella 370 delthyrium discussed 318 evolution discussed 318 evolution of 317 general geographic and stratigraphic distribution of the species referred to ; 99 INDEX. 825 Curticia— Continued, general stratigraphic distribution and number of Cam- . brian species and varieties of 110 mentioned 369 number of species of, in different ty^es of sediment. 160 elegantula described 369 general geographic and stratigraphic distribution tabulated 99 type specimen figured PI. I, fig. 2 Curticiidse, classification of 321, 322 distribution in Cambrian strata 316 genera and species referred to, described 369-370 general stratigraphic distribution and number of Cambrian genera and species of 112 number of Cambrian genera and species of 112 number of genera and species in monograph 113 species referred to, described 369-370 cUTvata, see Acrotreta. Custer, South Dakota, locahty near 167 cyane, see Obolus. Cyrtia, reference to, of "Acrotreta ? costata" 674 Cyrtoceras cambria mentioned 468 Czerhowitz, Bohemia, locality at 303 j Dakota, Minnesota, locality near 84s Dalame, Sweden, localities in 8y, 9e, 310n, 3901 Dale, T. N., mentioned 409 Dall, W. H., bibhographic references - 15 Dalman, J, A., bibhographic reference 15 Dalmanella, classification of, by Ulrich 308 compared with Protorthvi 739 muscle scars of, discussed by Ulrich 308 no Cambrian representatives 320 reference to, of "Leptsena melita" discussed 777 muUiseda, shell section figured text fig. 9, 299 parva, shell section figured text fig. 10, 299 subsequata, compared ^vith Orthis tricenaria by Uhich 308 muscle scars of, discussed by Ulrich 308 shell section figured text fig. 2, 299 subsequata group, compared \vith average Cambrian articu- late by Uhich 308 damesi, see Lingulella. Danaher Creek, Ovando quadrangle, Montana, locality near 4w Dane County, Wisconsin, localities in 85x, S85x, 85z, 328p Danish Flat, Bear Lake County, Idaho, localities near 55c, 163 Danzig, West Prussia, locality near 386d Darton, N. H., species named for 455 dartoni, see Obolus ( Westonia). daunus, see Eoorthis. Davidson, T., bibhographic references 15; 16 species named for 489 *'Davidsonella," discussed 565 "linguloides," discussed 565 "squama," discussed 567 davidsoni, see Lingulella. Davis, J. E., bibhographic reference 16 species named for 491 davisi, see Lingulella. Dawson, J. W., bibhographic references 16 Dawson, William E. . acknowledgments 12 Deadwood, South Dakota, localities near 88a, 164, 165, 355f Deadwood formation, note on localities in 144 Deadwood formation (Middle Cambrian), localities in. . . 164, 302e, 355b Deadwood formation (Upper Cambrian), localities in 3D2p, 302ti Dearbornia, described 614 classification of 321, 324 compared with Discinopsis 614 Obolus 614 Schizambon 614 Siphonotrcta 614 Trcmatobolus 313, 614 evolution of 317 general geographic and stratigraphic distribution of the species referred to , . 104 general stratigraphic distribution and number of Cam- brian species and varieties of Ill number of species of, in different types of sediment ... 160 shell substance 297 stratigraphic position mentioned 319 type species Dearbornia clarki 614 vascular markings discussed 311 Dearbornia clarki, described 614 general geographic and stratigraphic distribution tabu- lated 104 type of Dearbornia 614 type specimen figured PI. LXXXII, fig. 7 Dearborn River (North Fork), Montana, localities on 9k, 9m Dearborn River section, Montana, localities correlated with 3j, 4q, 4q', 4v, 4w, 5j, 83, 9k dccipiens, see Acrothck and Obolus mcconnclli. Dedham quadrangle, Massachusetts, locality in 5 Deep Creek, Wyoming, locality on 4j Deep Spring Valley, California, localities in 176, 178a definita, see A crotreta. Definitions 292-296 Delano, see Mount Delano. Delgadella, described 560 cardinal area discussed 303 classification of 321, 323 compared with Lingula 560 evolution discussed 319 evolution of 317 general geographic and stratigraphic distribution of the species referred to 103 general stratigraphic distribution and number of Cam- brian species and varieties of 1 10 number of species of, in the different types of sedi- ment 160 .type species " Lingulepis lusitanica" 560 lusitanica, described ,.. 560 cardinal area discussed 304 general geographic and stratigraphic distribution tabu- lated 103 type specimen figured PI. XXIX, fig. 5 Delgado, J. F. Nery, acknowledgments 12 bibliographic reference 16 genus named for 560 species named for 491 delgadoi, see Lingulella. Deltidium, compared with pseudodeltidiura 306 defined 293 development of 306 discussed 305-306 holoperipheral growth of 306 Delthyrium, defined 293 ■ discussed 305-306 Denmark, Cambrian, species of, listed 120-121 generalized section of Cambrian and Ordovician in, hsting included and correlated species and locahties 144-146 localities in 16h-l, 334, 334a-h See also Bornhobn. Dennis, see Moimt Dermis. Dental plates, defined '. 293 discussed 310-311 relation of, to spondyhum, discussed by Uhxh 308 Dental sockets, defined 293 depressa, see Acrotreta. descendens, see Acrotreta opMrensis. Deseret road, House Range, Utah, locality on Ho desiderata, see Elkania and Lingulella. desmopleura, see Eoorthis. desmopleura nympka, see Eoorthis. Deudraeth, Wales, locality at 366p Devils Lake, Wisconsin, localities near 81, 81b, 8I0, 328 Deweys Bridge, New York, localities near 109, 367k diablo, see Eoorthis. dice, see Billingsella. Dicelloceplialus, see Dikellocepkalus. Dicellomus, described 571 articulating processes discussed 307 cardinal area discussed 304 classification of 321, 323 compared with Acrotreta 312 Curticia 369 Linnarssonella tennesseensis 670 Obolella 592 Obolus 312 Obolus chinensis 3S7 evolution discussed 318 evolution of 317 general geographic and stratigraphic distribution of the species referred to 103 826 CAMBRIAN BRACHIOPODA. Dicellomus — Continued . general stratigraphic distribution and number of Cam- brian species and varietifesof 110 muscle scars discussed 312 number of species of, in different types of sediment... 100 pedicle semitube discussed 314 smface ornamentation discussed 302 tj'pe species "Lingula polita" 572 vascular markings discussed 311 appalachia, described 572 compared with Dicellomus politus 577 D icellomus sp . undt 578 general geographic and stratigraphic distribution tabu- lated 103 type specimen figured Fl. LIII, fig. 4a Tianus, described 573 compared with Dicellomus appalachia 572 Dicellomus pectenoides 575 Dicellomus politus : - - - 577 general geographic and stratigraphic distribution tabu- lated 103 stratigraphic position of type specimen discussed 574 tj-pe specimen figured PI- LIII, fig. 2 paTVUS, described 574 general geographic and stratigraphic distribution tabu- lated 103 type specimen figured PI. LXXXIX, fig. lib pectenoides, described 575 compared with Dicellomus politus " 577 general geographic and stratigraphic distribution tab- ulated 103 type specimen (?) figured PI. LII, fig. 6 politus, described 575 compared with Curticia elegantula 369, 370 Dicellomus appalachia 572 Dicellomus nanus 573 Dicellomus parvus 574 Dicellomus pectenoides 575 Dicellomus pTolificus 578 Lingulella pliaon 525 Obolella chromatica 672 Obolus sinoe 416 Oholus? sp . undt. f 423 Obolus (Fordinia) gilberti 429 Obolus ( Westonia) aurora 452 discussed 572 general geographic and stratigraphic distribution tabu- lated 103 intermediate between Obolus and Obolella. , 314 type specimen not figured. prolificus, described 578 general geographic and stratigraphic distribution tabu- lated 103 tj-pe specimen figured PL LXXXIX, fig. 10 sp. undt., described 578 general geographic and stratigraphic distribution tabu- lated 103 type specimen figured PL LII, figs. 7 and 7a dichotoma, see Acrothele. Dickinson County, Michigan, locality in 330b Dictyograptus slate (Upper Cambrian), in generalized section for Russia 143 in generalized section for Sweden, Denmark, Finland, and Norway, listing species and localities 145 localities in 309b,310t-v,321x,390g systemic reference discussed 98 Dictyograptus flabelliformis zone (Upper Cambrian), locality in.... 309h Dictyograptus zone, mentioned 515 Dictyonema zone, in generalized section for Cape Breton, listing included and correlated species and localities 131 mentioned 487 Diductor muscles, defined 293 Didymograptus slate, in generalized section for Sweden, Denmark, Finland, and Norway 144 Dikellocephalus \OUnus] fauna, mentioned 378 Dinobolus, classification 310 Hall and Clarke on development of 309 platform mentioned 309 Dinorthis, classification of, by Ulrich 308 compared with Hebertella 320 Protorthis (Loperia) dugaldensis 320 Dinor^A/s— Continued. cruralium mentioned -. 309 muscle scars of, discussed by Ulrich 308 no Cambrian representatives 320 subquadrata, cardinal process discussed 306 Discina, compared with Discinolepis 664 mentioned ^ 532 reference to, of Orbiculoidea contrarij discussed 722 reference to, of Orbiculoidea variaTis discussed 723 *'cxrfairnsis," discussed 723 ''pileolus," discussed 647,723 Disciaacea, classification of 321, 325 distribution in Cambrian strata 316 genera and species referred to, described 722-723 Discinella, association mentioned 357 Discinidse, classification of 321, 325 distribution in Cambrian strata 316 genera and species referred to, described 722-723 general stratigraphic distribution and number of Cambrian genera and species of 112 number of Cambrian genera and species of 112 number of genera and species in monograph 113 Discinisca, compared with Discinolepis 664 Discinolepis, described 664 cardinal area discussed 305 classification of 321, 324 evolution of 317 general geographic and stratigraphic distribution of the species referred to 105 general stratigraphic distribution and number of Cam- brian species and varieties of ill intermediate between Acrothele and Acrotreta 314 number of species of, in different types of sediment. . . 160 type species Discinolepis granulata 664 grunulata, described 664 general geographic and stratigraphic distribution tabulated 105 type of D iscinolepis 664 type specimen figured PL LXXXI, fig. 3 Discinopsis, described " 720 classification of. 321, 324 compared with AjCrothyra 721 Dearbornia 614 YorUa 611 evolution discussed 319 evolution of 317 general geographic and stratigraphic distribution of the species referred to 107 general stratigraphic distribution and number of Cam- brian species and varieties of Ill number of species of, in different types of sediment 160 reference to, of Discinopsis? sulcatus discussed 721 type species ^cro^rc/a? gulielmi 720 vascular markings discussed 311 gulielmi, described 720 compared with Discinopsis? sulcata 721 general geographic and stratigraphic distribution tabulated - 1G7 type specimen figured PL LXXXII, fig. 5 ? sulcatus, described 721 general geographic and stratigraphic distribution tab- ulated 107 type specimen figured PL LXXXII, fig. 6 discoideus, see Obolus. divaricator , see Lucinia. Division Clbl of Matthew (Middle Cambrian), in generalized sec- tion for Cape Breton , listing included speciesand localities. 133 localities in 2f , 2g, 301i, 308e^ Division Clb2 of Matthew (Middle Cambrian), in generalized sec- tion for Cape Breton, listing included species and localities. 133 locality in 308d Division Clb3 of Matthew (Middle Cambrian), in generalized sec- tion for Cape Breton, listmg included species and localities . 132 localities in 2i, 2k, 301a, 308d. 308g? Division Clb4 of Matthew (Middle Cambrian), in generalized sec- tion for Cape Breton, listing included species and localities . 132 localities in 308d, 308g? Division Clb5 of Matthew (Middle Cambrian), in generalized sec- tion for Cape Breton, listing included species and localities. 132 localities in 301b. 301d, 301f INDEX. 827 Division Clc of Matthew (Middle Cambrian), in generalized sec- tion for Cape Breton, listing included species and localities . 132 localities in 301g, 3011i, 301m, 301w, 301z, 308h Division Old of Matthew (Middle Cambrian), in generaUzed sec- tion for Cape Breton, listing included species and localities . 132 locaUtiesin 300,3011 Division C2a of Matthew (Middle Cambrian), in generaUzed sec- tion for Cape Breton, listing included and correlated species and locahties 132 locality in 307f Division C2b of Matthew (Middle Cambrian), in generalized sec- tion for Cape Breton, hsting included and correlated species and localities 132 locaUtiesin 31, 307g Division C2c of Matthew (Middle Cambrian), in generalized sec- tion for Cape Breton, Usting included and correlated species and localities 131 locahties in 301x, 301y, 307c? Division C3a of Matthew (Upper Cambrian), in generaUzed section for Cape Breton, listing included and correlated species and locahties 131 locaUtiesin lOr?, 301e, 301ii, 301t, 308a, 308b, 3D8f, 325b Division C3b of Matthew (Upper Cambrian), in generaUzed section for Cape Breton, Usting included and correlated species and locahties 131 locaUtiesin 301u, 307e, 307h, 307i, 307j, 325 Division C3c of Matthew (Upper Cambrian), in generaUzed sec- tion for Cape Breton, listing included and correlated species and localities 131 locaUtiesin 307, 307e, 307h, 307j, 308 Division C3c2 of Matthew (Upper Cambrian), in generaUzed sec- tion for Cape Breton, Usting included species and localities . 131 locaUty in 307a Division E is the Etcheminian, which also see for lists of locaUties. Division Ela, in detailed section on Dugald Brook, Cape Breton. . 134 Division Elb of Matthew (Middle Cambrian), in detailed section on Dugald Brook, Cape Breton, Usting included species and localities 134 locaUties in 13t, 13t', 344k Division Elc of Matthew (Middle Cambrian), in detailed section on Dugald Brook, Cape Breton, listing included species and localities 134 locaUtiesin 13t", 344g Division Eld of Matthew (Middle Cambrian), in detailed section on Dugald Brook, Cape Breton, listing included and cor- related species and localities 134 locaUties in 13t", 344e, 344m Division Ele of Matthew (Middle Cambrian), in detailed section on Dugald Brook, Cape Breton, Usting included species and locaUties 134 locaUty in 344h Division E2a of Matthew (Middle Cambrian), in detailed section on Dugald Brook, Cape Breton, listing included and cor- related species and locaUties 134 locaUties in 13d, 13d', 13d", 13f, 13g, 13p, 13p', 307d Division E2b of Matthew (Middle Cambrian), in detailed section on Dugald Brook, Cape Breton, Usting included and cor- related species and localities 134 locaUtiesin lOp, IDq, 13d, 13d', 344o Division E2c of Matthew (Middle Cambrian), in detailed section on Dugald Brook, Cape Breton, hsting included species and localities 134 locaUties in 13e, 3441 Division E3a of Matthew (Middle Cambrian), in detailed section on Dugald Brook, Cape Breton, listing included species and locahties 133 locaUtiesin 131, 131'. 3441 Division E3b of Matthew (Middle Cambrian), in detailed section on Dugald Brook, Cape Breton, Usting included species and locaUties 133 locaUty in 344 Division E3c of Matthew (Middle Cambrian), in detailed section on Dugald Brook, Cape Breton, Usting included species and localities , 133 locaUty in 344a Division E3d of Matthew (Middle Cambrian), in detailed section on Dugald Brook, Cape Breton, listing included and cor- related species and locaUties 133 locaUties in 13n", 344b, 344c Division E3e of Matthew (Middle Cambrian), in detailed section on Dugald Brook, Cape Breton, listing included and cor- related species and localities 133 locaUties in 13n', 344j Division E3f of Matthew (Middle Cambrian), in detailed section on Dugald Brook, Cape Breton, listing included and cor- related species and locaUties 133 locaUties in 13m, 13n, 344d Division P of Billings (Lower Ordovician), locaUties in 314c, 314d See also Quebec group. Division 2 of Matthew (Upper Cambrian), locaUty in 2i Division 3e ( ?) of Matthew (Lower Ordovician), locaUty in 301s Djupadal, Sweden, locaUties in 320a, 320n Dlouha Hora, Bohemia, locality on 345 Dobbs Linn, Scotland, locaUty at 316 Dodson Ford, Tennessee, localities near lD3a, 103b dolatus, see Obolus. DoigeUy, North Wales, locaUties near 318, 318c, 318f, 366g, 366h Dolgelly group, in generaUzed section for England, Scotland, and Wales, Usting species and localities 135 Dome Canyon, House Range, Utah, locaUties in llw, 30c, 30d, 30e, 31s, 31v Dome Canyon Umestone, in detailed section in House Range, Utah, Usting included and correlated species and locaUties. 157 Dome Lake, Bighorn Mountains, Wyoming, locality near 168 DomgUnt, EstUonia, Russia, locality at 396d doris, see Eoorthis. Dorsal valve, defined 293 reasons for preservation of, in Trematobolus 617 DowTi (County), Ireland, locaUty in 317 Dresbach, Minnesota, localities at 84, 84f Drinkwater mine. Silver Peak quadrangle, Nevada, locaUty near. . Iv DruidlnU Bum, Scotland, locaUty at 316b Dry Creek, Montana, localities on 150a, 152a, 152b, 153, 153a, 154 Dryton, England, locality at 3041 dubia, see Linguldla and Siphonofrcta. Dublin (County), Ireland, locality in 317a Dugald Brook, Cape Breton, detailed section of Middle Cambrian on, listing included and correlated species and locaUties. 133-134 locaUties on lOp, lOq, 13d, 13d', 13d", 13e-g, 13k, 131, 131', 13n, 13n', 13u", 13p, 13p', 13t, 13t', 13t", 344, 344a, 344b, 344d, 344f-i, 344k-m, 344o, 372f dugaldensis, see Protorthis (Loperia). Dugway Range, Utah, locality in 32t Dumfriesshire, Scotland, localities in 316, 316b Dunderberg mine. Eureka district, Nevada, locality near 66 Dunderberg shale (Upper Cambrian), detailed section, Usting included and correlated species and locaUties 139 locaUties in 61, 62, 66 mentioned 6SS, 6S9 Dunn County, Wisconsm, locaUties in 79a, 80, 82a, 100, 134, 134a Dunns shore, New Brunswick, locaUty at 301x Dutchess County, New York, Lingulella (LiTigulepis) acuminata in, discussed 548 localities in 32, 108, 367d, 367e, 367j D wight, W . B . , bibliographic references 16 Eagle Mills, New York, locality near 338y Eakles Mills, Maryland, localities at 16f , 47f East Bay, Cape Breton, locaUties on. . lOr, 131, 13q, 307j, 325, 325b, 372d East Braintree, Massachusetts, locality at 326b East Canyon, Oquirrh Range, ITtah, locaUty in 329c East Fork, see Paradise Dry Canyon East Gallatin River, Montana, locaUties on or near 4g', 4h, 155, 155a, 15ea, 156b, 157, 158, 158a Easton Station, New York, localities near 39a, 3381 East Point, Nahant, Massachusetts, locality at 326g East Prussia, localities in 386, 386a-c, 3861-k localities in, correlated with those of Russa 143 Eau Claue, Wisconsin, localities near 78a, 98, 98x Eau Claire County, Wisconsin, localities in 78a, 98, 98x Echmospli3STit€s limestone— CI (Ordovician), in generalized sec- tion for Russia, Usting species and locaUties 143 localities in 336. 336v, 3861-1 "Edge^vise beds" (Upper Cambrian), in generaUzed section for Missouri, Usting species and localities 137 localities in (see p. 137) Ilk, 369a referred to the Upper Cambrian 137 Edson, George, species named for 328 edsoni, see Eustella. 828 CA^IBRIAN BRACHIOPODA. Edwardstown, Quebec, locality in 319u Egan Canyon, Ecran Kange, Nevada, locality in 8f Egan Range, Nevada, locality in 8f Egeberg, Norway, locality at 323v Eggegmnd Island, Sweden, locality on 311 stratigrapliic position of bowlders found on, discussed 6S4 eggcgrundcTiMsy see Acrotrcta. Eichwald, C. E. von, bibliographic references 16 species named for 390 eichwaldi, see Obolus. Ekeruni, Oeland Island, Sweden, localities near 310e, 310f Elbe River. Germany, locality near 386e Eldon limestone (Middle Cambrian), detailed section, listing in- cluded and correlated species and localities 126-127 localities in 35g, 57ii Eldorado limestone (Middle Cambrian), detailed section, listing included and correlated species and localities 140 localities in 54, 55, 55b, 57 elegans, see Oholus. ekgantula, see Curticia and Eostrophomena. Elkania, described 561 cardinal area discussed 304 classification of 310, 321, 323 compared with Monobolina 37S, 410 Obolus and Obolus (Fordinia) 428 Schuchertina 585 development of area in 561, 562 evolution discussed 318 evolution of 317 general geographic and stratigraphic distribution of the species referred to 103 Hall and Clarke on development of 309 muscle scars discussed 312 number of Ordovician species and varieties of 113 number of species of, in dijfferent types of sediment.. 160 amUgua, described . . 562 compared with Elkania desiderata 563 general geographic and stratigraphic distribution tab- ulated 103 platform discussed 310 t5T)e specimen figured PI. LI, fig. 2a desiderata, described : 562 compared with Dicellomus pectenoides 575 Elkania ambigua l 562 Elkania ida 563, 564 Obolella 562 Obolus 563 Obolus apoUinis 562 Obolus {Fordinia) perfectus 430 discussed 561 general geographic and stratigraphic distribution tab- ulated 103 'platform discussed 310 type specimen not figured . ida, described 563 general geographic and stratigraphic distribution tab- ulated 103 platform discussed 310 type specimen not figured. Elkaniinag, classification of 321, 323 genera and species referred to, described 561-564 Elk Pass, Yellowstone National Park, Montana, locality in 302f Elk Range, Colorado, locality in 360c ella, see Obolus ( Westonia). ella onaquicnsis, see Obolus ( Westonia). Elliptocephala asaphoides, association mentioned 473, 531, 605 Elliptocephala asaphoides fauna, mentioned 594 Ells, R. W., species named for 496 eUsi, see Lingulella. elongata, see Obolella crassa. elongatus, see Obolus ( Westonia). El Paso County, Colorado, locahties in 186, 186a, 187, 360, 36Da, 360d, 360f, 360g El Paso County, Texas, locahty in 353b Elvins, Missouri, localities near 369a, 369c Elvins formation (Upper Cambrian), in generalized section for Missouri, listing species and locaUties 137 localities in 11 1, 369, 369d Ely, Nevada, locality near 8p Ely Mountains, Nevada, locaUties in 7k, 31 Emigrant formation (Upper Cambrian), localities in 7s» 7v, 7x~z, 8a, 8b', 8r note on ; 137 Emigrant Pass, Nevada, localities near 7x-z, 8a, 8b' Emigrant Peak, Nevada, locaUties near 7r, 7s, 7v, 8r Emigsville, Pennsylvania, localities near 49, 49b, 49c, 49w, 34S Emmons, E., bibliographic references 16 species named for 685 Emmons, MV. H., bibliographic reference 16 emmonsi, see Acrotreta. Endlich, F. M., species named for 342 endlichi, see Micromilra sculptilis. Engervlk, Norway, locality at 323e England, Cambrian species of, hsted 120-121 generalized .section of Cambrian and Ordovician in, listing species and localities 135-136 localities in 304, 304a-l, 304n-p " Eoobolus," characterized 377 synonym of Obolus 377 Eoorthinas, classification of 321, 326 genera and species referred to, described 772-795 surface ornamentation discussed 303 Eoorthis, described 772 cardinal area discussed 305 classification of 321,326 compared with BilUngsella 755 Finkelnhurgia 793, 794 Orusia 765 cmralium mentioned 309 evolution discussed 320 evolution of 317 general geographic and stratigraphic distribution of the species referred to 108, 109 general stratigraphic distribution and number of Cam- brian species and varieties of HI intermediate between BilUngsella and Ordovician orthoids 77S intermediate between BilUngsella and Orthis 772 mentioned 761 muscle scars discussed !... 31S number of Ordovician species and varieties of 113 number of species of, in different types of sediment. . . 160 pseudospondylium discussed 307 reference to, of Eoorthis atava discussed 774 Eoorthis christianise discussed 775 Eoorthis ? diablo discussed 779 Eoorthis johannensis discussed 782 Eoorthis salten^is discussed 788-789 Eoorthis sp. undt. a mentioned 792 "Leptsena melita" discussed 777 " Orthis sp. Pompeckj " mentioned 793. type species " Orthis remnicha" 773 Ulrich on spondylium 30S vascular markings discussed 311, 312 agreste, described 773 compared with Eoorthis sp. undt. c 79S general geographic and stratigraphic distribution tab- ulated lOS tjT>e specimen figured Pi. LXXXIX, fig. 6 atava, described 774 general geographic and stratigraphic distribution tab- ulated lOS type specimen figured PI. XCV, fig. 7 bavarica, described 775 general geograpliic and stratigraphic distribution tab- ulated lOS type specimen figured PI. XCVII, fig. 4 christianise, described 775 compared with Eoorthis daunus 776 Eoorthis tullbergi , 799 Eoorthis loimani 791 does not include Eoorthis daunus 775, 776 does not include Eoorthis tullbergi 776, 790 general geographic and stratigraphic distribution tabr ulated 108 restricted to the specimens from the Ceratopyge shale . . 775 type specimen not figured. INDEX. 829 EooTthis daunus, described 776 characterized 775 compared v-^th Eoortliis chmtianiss 775 Eoorthis tuUbergi 790 Eoorihis wimani 791 general geographic and stratigraphic distribution tab- ulated 108 the " Orthis christianise'^ iroTa the Ceraiopj/^e limestone 775 type specimen figured PI. XCV, fig. 2a desmoplcura, described 777 compared with Eoortliis kayseri 782 Eoorthis linnarssoni 783 Eoorihis pagoda 785 Eoorthis u'ichitaensis 790 general geographic and stratigraphic distribution tab- ulated 108 type specimen figured PI. XCVI, fig. Ih desmopleura nympha, described 778 general geographic and stratigraphic distribution tab- ulated 108 type specimen figured PI. XCVI, fig. 2 ? diablo, described 778 general geographic and stratigraphic distribution tab- xilated 108 type specimen figured PI. XCIII, fig. 3 doris, described 779 general geographic and stratigraphic distribution tab- ulated 108 type specimen figured PI. XCVII, fig. 13a Tuistingsensis, described 779 general geographic and stratigraphic distribution tab- ulated 108 type specimen figured Pi. XCPV, fig. 3 iddiTigsi, described 780 compared with Eoorthis newtonen^s 784 general geographic and stratigraphic distribution tab- ulated 108 type specimen figured PI. XCI, fig. 3 indiaTwla, described 780 compared with Eoorthis doris 779 Eoorthis iddingsi 780 Eoorthis newtonensis 784 Eoorthis primordialis 785 general geographic and stratigraphic distribution tab- ulated 108 tj-pe specimen figured PI. XCIVj fig. 2 johannensis, described 781 compared with Eoorthis hastingscnsis 779 general geographic and stratigraphic distribution tab- ulated 108 type specimen figured PI. XCVII, fig. 10 "kayseri, described 782 general geographic and stratigraphic distribution tab- ulated lOS type specimen figured PI. XCVII, fig. 6a kichouensis, described 782 general geographic and stratigraphic distribution tab- ulated 108 type specimen figured PI. LXXXIX, fig. 5 linnarssoni, described 782 compared with Eoorthis Vayseri 7S2 general geographic and stratigraphic distribution tab- . ulated 108 tj'pe specimen figured PI. XCVII, fig. 5a ■melita, discussed 777 ■newherryi, described 783 compared with Eoorthis zcno 792 general geographic and stratigraphic distribution tab- ulated 108 type specimen figured text fig. 69B, 783 -newtonensis, described 784 general geographic and stratigraphic distribution tab- ulated IDS type specimen not figured. joagoda, described 7S4 general geographic and stratigraphic distribution tab- ulated 108 type specimen figured PI. XCVII, fig. 12 Eoorthis papias, described 785 general geographic and stratigraphic distribution tabulated 108 type specimen figured PI. XCI, fig. 4 primordialis, described 785 general geographic and stratigraphic distribution tabulated , 108 "intermediate between Orthis and Spirifer" 785 type specimen figured PI. XCVII, fig. 1 remnicha, described 786 cardinal process discussed 306 compared with Billingsella exporrccta 755 BiUingsella retroflcxa 761 Eoorihis ? diablo 778 Eoorthis indianola 780 Eoorthis newberryi 783 Eoorthis remnicha tcxana 787 Eoorthis remnicha winfieldensis 788 . Eoorthis taid 789 Eoorthis wichitaensis 790 Eoorthis wimani 791 Finkclnburgia osceola 795 Orusia Icnlicularis 767 general geographic and stratigraphic distribution tabulated 108 tj'pe specimen not figured. shell section figured text fig. 7, 299 remnicha sulcata, described 787 compared ^yith Finkelnburgia osceola 795 general geographic and stratigraphic distribution tabulated 108 type specimen figured PI. XCII, fig. la remnicha tcxana, described 787 general geographic and stratigraphic distribution tabulated 108 type specimen figured PI. XCII, fig. 4 remnicha winfieldensis, described 788 compared with Eoorthis remnicha 786 Eoorthis zcno 792 general geographic and stratigraphic distribution tabulated 108 type specimen figured PI. XCI, fig. 2 saltensis, described 788 compared with Orusia lenticularis 768 general geographic and stratigraphic distribution tabulated 180 type specimen figured PI. XCVII, fig. 11 tatei, described 789 general geograpMc and stratigraphic distribution tabulated 108 type specimen figured PI. XCVII, fig. 15a thyone, described 789 general geographic and stratigraphic distribution tabulated 108 type specimen figured text fig. 70A, 789 tullbergi, described 790 general geographic and stratigraphic distribution tabulated 108 not a variation of Eoorthis christianise 776, 790 type specimen figured PI. XCV, fig. 3 wichitaensis, described 790 compared with Eoorthis desmopleura 777 Eoorthis indianola 780, 781 Eoorthis linnarssoni : 783 Eoorthis pagoda 785 Eoorthis thyone 789 Eoorthis wichitaensis Iseviusculus 791 general geographic and stratigraphic distribution tab- ulated IDS type specimen figured PI. XCIV, fig. 1 wichitaensis Iseviusculus, described 791 compared with Eoorthis wichitaensis 790 general geographic and stratigraphic distribution tab- ulated 108 type specimen figured PI. XCIV, figs. Ip-s wimani, described 791 characterized 775-776 compared with Eoorthis christianise 775 830 CAJVIBRIAN BRACmOPODA. EooTthis wimani — Continued. general geographic and stratigiapliicdistribution tabu- lated 108 type specimen figured PI. XCV, fig. 4a zeno, described 792 general geographic and stratigraphic distribution tab- ulated lOS type specimen figured text fig. TLV, 792 sp. undt. a, described '92 general geographic and stratigraphic distribution tab- ulated 108 type specimen not figured. sp. undt. b. described 792 general geographic and stratigraphic distribution tab- ulated 109 type specimen not figured. sp. undt. c, described "93 general geographic and stratigraphic distribution tab- ulated 100 type specimen figured PI. LXXXIX, fig. 7 sp. undt. d, described 793 general geographic and stratigraphic distribution tab- ulated 109 type specimen figxn:ed PI. LXXXIX, fig. 8 sp. undt. e. described 793 general geographic and stratigraphic distribution tab- ulated 109 Eoorthoids (Cambrian), shell structure compared with that of Ordovician Protremata 300 Eophi/ton, sandstone (Lower Cambrian), in generalized section for Sweden, Denmark, Finland, and Norway, listing species and localities 146 localities in 390j, 390k EostTophomcTia, described 795 cardinal area discussed 305 classification of 321, 326 evolution discussed 320 evolution of 317 general geographic and stratigraphic distribution of the species referred to 109 general stratigraphic distribution and number of Cam- brian species and varieties of Ill number of species of, in different types of sediment. . 160 type sp. " StTophomena ( Eostrophomena) elegantula " . . 796 elegantula, described 796 general geographic and stratigraphic distribution tabu- lated 109 type specimen figured PI. XCV, fig. 6 "walcotti," discussed 796 Ephebic, defined 294 erecta, see yisusia {JameseUa). Erinnys venulosa , association mentioned 498 €Tos, see LinguMla {LinguUpis). Erras, Esthonia, Russia, localities at 337, 337d Ersholmen Island, Sweden, locality on 311v eryx, see AcTOthele matthewi. Escabrosa Ridge, near Bisbee, .Vrizona, locality on 358b Escanaba River, Michigan, locality on 330a escasoni, see Obolus (Westonia). Escasonie Indian Reservation, Cape Breton, locality near 344e Escasonie shore. Cape Breton, locaUty on 325b Esmeralda County, Nevada, localities in 11, Im, Ip, Iv, 7r, 7s, 7v, 7x-z, 8a, 8b', 8r, 174c, 176, 184, 3131 Essex,New York, locality near 367h Essex County, Massachusetts, localities in 326c, 326g Essex County, New York, locaUties in 77, 136, 338r-t, 367c, 367f-h Esthonia, Russia , localities in 9d, 336b-d, 336f, 336h, 3361, 336m, 336r-t, 336v, 336z, 337, 337a-f , 337g-l, 337 1, 395, 395a-V, 395x, 396, 396a-d, 396g-j, 396ni-y esthonia, see Schizambon. EstiUviUe quadrangle, Tennessee, locality in 374e Estillville pike, Tennessee, locality near 102o Etage C of Barrande (Middle Cambrian), in generalized section for Bohemia, listing species and localities 124 localities in 345c, 346f-h, 3451 Etage dl of Barrande (Lower Ordovician), In generalized section for Bohemia, listing species and localities 124 locaUties in 303b, 303d, 303e, 303g-l Etage d2 of Barrande (Lower Ordovician), in generalized section for Bohemia 124 Etage d3 of Barrande (Lower Ordovician), in gcneraUzed section for Bohemia, listing species and localities 124 localities in 303, 303a, 303p Etage d4 of Barrande (Ordovician), in generalized section for Bohemia, listing species and localities 124 localities in 303m-o Etage Ic of Brogger (Middle Cambrian), in generalized section for Sweden, Denmark, Finland, and Norway, listing species and locaUties 146 locaUties in 324a, 324l> Etage Id of Brogger (Middle Cambrian), in generaUzed section for Sweden, Denmark, Finland, and Norway, listing species and locaUties 145 locaUty in 324c Etage 2b of Brogger (Upper Cambrian), in generaUzed section for Sweden, Denmark, Finland, and Norwaj', listing species and localities 145 locaUties in 323 1-n Etage 3aa of Brogger (Upper Cambrian), in generalized section for Sweden, Denmark, Finland, and Norway, listing species andlocaUties 145 Etage 3a^ of Brogger (Upper Cambrian), in generalized section for Sweden, Demnark, Finland, and Norway, listing species and locaUties 145 locality in 323w See also Ccratopyjc slate. Etage 3ar of Brogger (Passage beds), in generalized section for Sweden, Denmark, Finland, and Norway, Usting species and localities 144 localities in 323d, 323e, 323e See also Ceratopyge limestone. Etcheminian, detailed section of, listing included and correlated species and localities 133-134 Elb (Middle Cambrian), localities in 13t, 13t', 344k Elc (Middle Cambrian), localities in 13t", 344^ Eld (Middle Cambrian), localities in 13t", 344e, 344m Ele (Middle Cambrian), locality in 3441i E2a (Middle Cambrian), localities In 13d, 13d', 13d", 13f, 13g, 13p, 13p', 307d. E2b (Middle Cambrian), localities In IDp, lOq, 13d, 13d', 344o E2c (Middle Cambrian), localities in 13e, 3441 E3a (Middle Cambrian), locaUties in 13 1, 13 1', 3441 E3b (Middle Cambrian), locality in 344 E3c (Middle Cambrian), locality m 344a E3d (Middle Cambrian), localities in 13n", 344b, 344c E3e (Middle Cambrian), locaUties in 13n', 344} E3f (Middle Cambrian), localities in 13m, 13n, 344d. (Lower Cambrian), locality in 314b Etheridge, R., jr., bibUographic references. 1& species named for 346, SOT Etheridge. R. [Salter, J. W., and], bibUographic reference 23- ethiTidgei, see BucntUa and ificromitra (Paierlna). Etowah County, Alabama, localities in 137, 138, 139, 361 Ettrick, 'Wisconsin, locality at 100a euglyphus, see Obolti^ ( Westonia). " Euobohijs." characterized 377-378. compared with "Aeriiis," " Schmidt ia,'' and " Thysanotos'' by Mickwitz 434 Lingiilclla and Obolus 378 Obolus (Schmidtia) 442.445 mentioned , 542 synonym of LinguJella 378 Eureka, Utah, localities near 34n, 34s' Eureka County, Nevada, localities in 221, 313c, and those in Eureka district, which see. Eureka district, Nevada, localities in 52, 54, 56, 55b, 56, 67, 57b, 58, 59, 60, 61, 62, 62a, 63, 64, 65, 66, 201, 201a, 202, 203, 203a, 204, 205, 206a, 209, 211, 313h, 313j Eureka district section, in detail, listing included and correlated species and locaUties 139-140- euTekensis, see Orusia. Eraope, zoologic list of Cambrian species of, gi\'ing distribution by countries 120-121 zoologic list of Ordovician species of 123. excelsis, see Trematobolus. exigua, see Linguhlla (Lingulepis). erimia, see Lingula. INDEX. 831 exporrecta, see Billingsella. exporrecta rugosicostata, see BiUiiigsella. Exmilans limestone (Middle Cambrian), locality in 320d See also ConocoTyphe eisulans zone. Fib of Owen (Upper Cambrian), localities in 328h,3391 F4gels3,ng, see FogelsAng. Falma Brook, Estbonia, Russia, locality on 396o **FairTiew formation," discussed 131 Fall, Esthonia, Russia, localities near 396b, 396c, 3961 Fall River, Massachusetts, locality near 326a Falls Greet, Texas, localities near mouth of 14e, 14q False area, defined 294 Families, general stratigraphic distribution of, and number of Cambrian genera and species in 112 number of genera and species of, in the monograph 113 number of Ordo\ician genera and species in 113 Fandango Spring Canyon, Dugway Range, Utah, locality in 32t Fanglanchon, China, localities near C72, C74 Fanton Island, Sweden, localities on 321, 321a-d, 321o favosa, see OholeUa (Glyptias). Feistmantel, K., species named for 392 feistmanteli, see Oholus. Felbabka, Bohemia, locality at 345b ferrwginea, see Lingulella, fe^inata, see Nisusia. festinata traTi^ersa, see Nisusia. Ffestiniog, North Wales, localities near 305t, 366a, 366f, 8663, 366s Field, British Columbia, localities near 14s, 35f, 35k, 57e, 57f, 57], 57m, 57n, 57r, 58j-l, 58p, 58r, 58s See also Mount Field. Fillmore, Utah, locality near 33n Finkelnburg, W. A., acknowledgments 12 genus named for 794 species named after 795 fiiikelnburgi, see Finkelntmrgia. FinkelnbuTgia, described 793 cardinal area discussed 305 classification of 321, 326 evolution discussed 320 evolution of 317 general geographic and stratigraphic distribution of the species referred to 109 general stratigraphic distribution and number of Cambrian species and varieties of Ill muscle scars discussed 313 number of species of, in different types of sediment. . . 160 pseudospondylium discussed 307 type species "Orthis ( Finkdntnagia) finkelnburgi" 794 Ulrich on spondylium 308 vascular markings discussed 313 fiTikelnburgi, described 794 compared with Finkdnburgia osceola 793, 794 general geographic and stratigraphic distributiontabu- lated 109 type specimen flgin-ed PI. XCIII, fig. 2 osceola, described 795 compared with Eoorthis remnicha 794 Eoorthis Tcmnicka sulcata 787 FinkdnbuTgia finkel-nlniTgi 793,794 general geographic and stratigraphic distribution tabu- lated 109 type specimen figured Fl. XCIII, fig. Id oscecla corrugata, described 795 compared with FinkelribUTgia osceola 795 general geographic andstratigraphic distribution tabu- lated 109 type specimen not figured. Finland, Cambrian species of, listed 120-121 generalized section of Cambrian and Ordoviciap in, listing included and correlated species and localities 144-146 localities in 311d-f, 311q-t, 311w-y stratigraphic position of bowlders in Baltic region discussed 454 flnlandensis, see Obolus ( Weslonia). First Creek, Tennessee, locality near 11a First Creek Gap, Tennessee, locality in 14a Fish Lake Valley, Nevada, locality near 175 Fish Spring Range, Utah, localities in. 15d, 15p, 15x, 33d, 34^, 341, 329d Fish Springs, Utah, localities near 33d, 34g, 329d Flagabro, Sweden, locality at 309b Flathead formation ( Middle Cambrian), locality in 156a Flathead River (South Fork), Montana, locality near 4v Flathead sandstone, note on stratigraphic position and correlation of 137 Flathead shales (Middle Cambrian), locaUties in 4g, 4h, 4p note on stratigraphic position and correlation of 137 Flat River, Missouri, localities at llm, 369 Fletcher, Virginia, locality near 331 Flexure line, defined 294 Flinders Range, South Australia, localities in 315b-d Floyd County, Georgia, localities in. .13c, 14, 96, 96b, 138a, 140a, 140c, 362a fiumenis, see Lingulella. Foerste, A. F. [Shaler, N. S., and], bibliographic reference 24 Fogelsang,Sweden, locaUties at. 309, 309a, 309h, 310h, 310t, 320d, 321z, 390b Foramen, defined 294 Foraminal tube, defined ' 294 Forckkammeri zone, in generalized section for Cape Breton, listing included and correlated species and localities 132 See also Paradoxides forchhammeTi zone. Ford, S. W., bibliographic references 16,17 subgenus named for 428 (FoTdinia), see Obolus (Fordinia). Forgey Creek, Teimessee, locality on 122a Formations, systemic reference discussed 98 formosa, see Mickvntzia. Fort Ann quadrangle. New York, locaUties in 20, 20a, 21a, 22, 34a, 38, 38a, 367a, 3671 Fort Cassin, Vermont, locality near 227 Fort Logan quadrangle, Montana, locaUty in 9Ii Fort Mountain sandstone, section of 131 Fort SiU, Oklahoma, locaUties northwest of 9p-x, 9z, 12j note on development of Reagan sandstone near 142 Fossil Butte, Nevada, locality at 216a Fosters Point , Newfoundland, locaUties near 6i, 6s Fourmile Creek, Gallatin County, Montana, locaUty on 340b Fox Glen, Wisconsin, locaUty at lOv fragilis, see Obolus. France, Cambrian species of, Usted 120-121 locaUties in 342, 342a Franconia, Minnesota, locaUties at 82c, 97b, 97s Franklin County, New York, locaUties in Ill, 338u Franklin County, Pennsylvania, locaUties in 49d, 346b Franklin County, Vermont, localities in 16n, 25, 25a, 26, 28, 28a, 87, 87', 319e-g, 319j, 319k, 319m, 319q-s, 319v, 319y, 319z, 392p franklincTisis, see Lingulella. Franklin Range, Te.xas, locaUty in 353b Freeh, Fritz, bibliographic reference 17 Fredericktou-n, Missouri, locaUty at 369f Fremont Coimty, Wyoming, locaUties in 302e, 302p French Creek, New York, locaUty at 367f French Creek, South Dakota, locality on 355c Freshwater Springs, see Resting Springs. Fruitville, Pennsylvania, locaUty near 12v fuchsi, see Lingulella. Fucoid beds, in generalized section for England, Scotland, and Wales, listing species and localities 136 Fucoid sandstone (Lower Cambrian), in generaUzed section for Russia - 144 in generalized section for Sweden, Denmark, Finland, and Norway, listing species and localities 146 localities in 309c, 309d, 396q Gadsden, Alabama, locaUties at and near 137, 138, 139 Gafle, see Gefle. Gagel, C, bibliographic reference 17 Galena, South Dakota, locality at 17j Gaiesville, Wisconsin, locality near 79x Gallatin, Montana, locaUties near 302, 302j, 302k Gallatin County, Montana, locaUties in 4g, 4h, 4k, 4p, 147a, 148a, 149a, 150a, 151, 151a, 152, 152a, 152b, 153, 153a, 154, 155, 155a, 156a, 156b, 157, 158, 158a, 159, 160, 160a, 161, 302, 302a, 302j, 302k, 302n, 302t, 340b Gallatin formation, note on stratigraphic position of 137 Gallatin formation (Middle Cambrian), localities in 4k, 4u Gallatin formation (Upper Cambrian), localittesin... 4r, 148a, 160, 302f Gallatin quadrangle, Wyoming, locaUries in 302b, 302h Gallatin Range, Wyoming, locaUty in 3021 832 CAMBRIAN BEACHIOPODA. Galiatin Valley, Montana, localities in 156b, 160a, 161, 302a, 302c, 302s, 302n, See also East and West Gallatin rivers. Gamage, Miss A. O., species named for , 645 gamagti, see Acrothcle. Gap Creek, Tennessee, locality near 18 Garfield County, Colorado, localities in 3g, 360h, 360i Garfield Pe^, Wyoming, locality near 302o Garth, North Wales, locality at 366q Gastrikland, Sweden, locality in 321n Gefle, Sweden, localities near 311, 311b, 311c. 311g-o, 321e-m Gefleborg, Sweden, localities in 311, 311b, 311c, 311g-o, 321e-m gemma, see Acrolrcta and Bicia. gemmuia, see AcTotreta. Genera, alphabetic list of those in monograph, giving number of species of each occurring in the different types of sediment. 160 general geographic and stratigraphic distribution and num- ber of 9S-109 habitat of, discussed and tabulated 160 number of Ordoyician 113 species referred to listed, giving general geographic and stratigraphic distribution and number of 98-109 stratigraphic distribution and number of Cambrian 110-113 zoologic list of Cambrian, giving stratigraphic distribution and numbers of species 110-111 zoologic list of Ordovician, giving numbers of species 113 Geneva (Copenhagen), Utah, localities near.. Sly, 32c, 32n, 32y, 33t, 34m Genitalia, shown in figure 374 Genital markings, defined 294 " Genre" nebulosa, discussed 722 Geographic distribution tables 114-123 Geographic and stratigraphic distribution tabulated 98-109 Geological Survey of Canada, acknowledgments 12 Geologic data 98-291 George River station. Cape Breton, locality near 307d Georgia, Cambrian species of, listed 114^119 generalized section of Cambrian in, listing included and cor- related species and localities 147 localities in... . 13c, 14, 59m, 96, 96b, 96x, 138a, 140a, 140c, 362, 362a Georgia, Vermont, localities near 25, 28a, 319g, 319j, 319k, 319m Germany, Eoorthis daunus in drift blocks in 776 localities in 303c, 303f , 386, 386a-l See Bavaria, East Prussia, West Prussia, Mecklenburg- Schwerin, and Posen. Gerontic, defined 294 Gibraltar Bluff, Lodi, Wisconsin, locality at 86 Gilbert, G. K., species named for 429 gilberti, see Obolus (Fordinia). Gillis Brook, Cape Breton, localities on 13i, 13ni, 13q, 13r, 307e Gillis Hill, Cape Breton, locaUty near 3n Girty, George n., acknowledgments 13 species named for 667 girtyi, see LinnaTSSonella. Girvan District, Scotland, locality in 316a Gislof, Sweden, locality at 320j Givens Ford, Cowan Creek, Alabama, locality near 94o Givens Mill, Cowan Creek, Alabama, localities at 94z, 94xs Gjogrefos, Norway, locality at 323s Glauconite limestone (Passage beds), in generalized section for Russia, listing species and localities 143 localities in 336y], 386a, 386b, 396h-o Glauconite sandstone (Passage beds), in generalized section for Russia, listing species and localities 143 localities in 396, 396a-f Glen Eyrie, near Manitou, Colorado, locality near 360f Glenwood Springs, Colorado, localities at 3g, 360h, 3601 Glommen River, Norway, locality on 323u Glossina acer, compared with Obolus (Acritisf) rugatus 441 Glote, Sweden, locality at 32Dw {Glyptias), see Obolella (Glyptias). Gold Camp, Caballos Mountains, New Mexico, locaUty near 327 Goodhue County, Minnesota, localities in 86a, 113 Goodwin Canyon, Eureka district, Nevada, locality in 209 Goose Creek Canyon, see Big Goose Creek Canyon. Gordon Creek, Montana, localities near 4q, 4q', 4v, 8j Gordon Mountain, Montana, localities near. 4q, 4q', 8j Gorlmm, Frederic P., bibliographic reference 17 Grabau, A. W., bibliographic reference \] Grabau, A. W., and Shimer, IT. W., bibliographic reference 17 gracia, see A crotreta. Graham County, Arizona, localities in 9o, 358 Granboda, Aland Island, Finland, locality at 311r Grand Canyon of the Colorado, Arizona, locaUtiesin 17c, 73, 73a, 73b, 74, 74b, 74c, 74d, 75 grandis, see Lingulella and Lingulclla Isevis. Grand Teton quadrangle, Wyoming, localities in 4e, 4m-o Granite County, Montana, locaUties in 302q, 302r, 340e Grantsville Peak, Stansbury Range, Utah, locaUties near 32f, 32g, 32j, 32k, 32o, 34u, 34v granulata, see Acrothele {Redlickella) , Botsfordia, Discinolepis, and Eutorgina. Granville, New York, locaUties near 34a, 38, 38a, 367a See also Middle, North, and South Granville. granvillensis, see Lingulella. Gravel River, British Columbia, locaUty on 306 Gray, J. E., bibliographic reference 17 Great Belle Island, Newfoundland, locality on 114b stratigraphic position of beds discussed 482 Great Britain, see also England, Scotland, Ireland, and Wales. Great Northern shaft, near Twobit, South Dakota, locaUty at 17k Greene County, Tennessee, localities in 117, 117c Greene County, Virginia, locality in 331 Greeneville, Tennessee, localities near 117, 117c, Greeneville quadrangle, Tennessee, locaUtiesin 102c, 103, 103a, 103b, 104, 122a, 374b Green Lake County, Wisconsin, locality in 328d " Green sand " (Ordovician), locality in 337i Green's ranch. White Pine County, Nevada, locaUty near 313e Greenwich, New York, locaUties at and near 33, 33b, 35, 35a, 36b, 39a, 338f-li, 3381, 338p. 338z See also North Greenwich. gregwa, see Lingulella (Lingulepis). gregwa robusta, see Lingulella (Lingulepis). Gregwa Brook, Cape Breton, locaUties on lOp', 344c Gronhogen, Oeland Island, Sweden, locaUty at 310w Gronwall, Karl A., acknowledgments 12 bibliographic reference .■ 17 Groome district, Nevada, locaUty in 313g groomi, see Obolella. Gross Lohovic, Bohemia, locality at 345j Gruguetta, Sardinia, locaUty at 354d Gudhem, Sweden, locaUties at 320, 320b, 320y gulielmi, see Discinopsis. Giirich, G. , bibUographic references 17 Gutturu Sartu, Sardinia, locality in the valley of 354a Gwemy-y-Barcud, North Wales, locality at 318u Gwynfynydd, North Wales, localities at 318c, 318f Habitat, table showing number of species of each genus occurring in the different t5i)es of sediment 160 HackAs, Sweden, locality in 320t Hague, Arnold , bibliographic references 17 Halfmoon mine, near Pioche, Nevada, localities at 7k, 333b Hall, J. , bibliographic references 17 Hah, J., and Clarke, J. M., bibliographic references 18 HaU, J.,and Whitfield, R. P., bibUographic reference IS Hamburg limestone, detailed section, listing included and corre- lated species and locaUties 139 Hamburg mine. Eureka district, Nevada, loca-lity near 61 Hamburg Ridge, Eureka district, Nevada, localities on or near. . . 201, 2Dla, 203a, 204, 313h Hamburg shale=Dunderberg shale. Hamilton, Montana, locaUty near 161 Hammond, New York, locality at 338w Hancock, Albany, bibliographic reference 18 terminology of 292 Hancock County, Tennessee, locality in 105 Hanford Brook, New Brunswick, localities on 2f-i, 2k-m, 3a, 301, 301a, 301b, 301d, 301h, 3011, 301v, 308e HardingviUe, New Brunsmck, locality at 301s Hardyston quartzite (Upper Cambrian), locality in lie Hare Bay, Newfoundland, locality on 314g Harjedalen, see Herje&dalen. liarlanensis , see Wimanella. Harlan Knob, Tennessee, localities near 9, 121, 121a, 123, 124, 124a INDEX. 833 Harlech grits (Middle Cambrian), in generalized section for Eng- land, Scotland, and Wales, listing species and localities- . . 136 localities in 318n, 318o, 366b Harlech group (Middle Cambrian), locality in 318q Harley, England, locality near 304i Harpers Ferry, AVest Virginia, locality near 47c Hartt, C. F., bibliographic references IS Hastings cove, near St. John, New Brunswick, localities at 2s, 2t hastingsensis , see Eoortfiis. Hawkins County, Tennessee, localities in 9, 9a, 12q, 101, 101a, 101b, 102, 102c, 103, 103a, 103b, 104, 119, 121, 121a, 122, 122a, 123, 124, 124a, 374b, 374d Hayden, F. V. , bibliographic reference IS species named for 338 Hayden, F. V. [Meek, F. B., and], bibhographic references 21 haydeni, see Mkromitra. Hayes, C. W., bibliographic references 18 species named for 505 hayesi, see LinguUlla. Hayward Creek, Massachusetts, locality on 5 Heart-shaped cax-ity, defined 294 Heart-shaped pit, shown in figure 374 Hebert, M., species named for 506 Eebertella, classification of, by Uhich SOS compared with Dirwrthis 320 cniralium mentioned 309 heberti, see Linguldla. Hebron, see North Hebron. Hector, British Columbia, localities near 35c, 35g, 35h, 57c, 57g, 57k, 57s, 57y, 58z Hedemarken, Norway, localities in 8v, 323b, 323t, 324, 324d Helena, Alabama, localities near 17b, 56c Helena, Montana, Dicellomus politus from, discussed 577 localities near 4u, 302s, 340a See also Mount Helena. Jielena, see Linguldla and Protorlhis. Hehnersen, Gr^goire de, genus named for 3G8 Eelmersenia, described 307 apical foramen in, discussed 367,308 cardinal area discussed 303 classification of 321, 322 evolution discussed 318 evolution of 317 false cardinal area mentioned 318 general geographic and stratigraphic distribution of the species referred to 99 general stratigraphic distribution and number of Cam- brian species and varieties of 110 muscle scars not sho\vn in 312 number of species of, in the dilTerent types of sedi- ment 160 pedicle opening mentioned 318 surface ornamentation discussed 301, 302 type species discussed 367, 368, 369 type species " Siphonotreta ladogensis" 367 "jeremcjewi," discussed 368, 369 IMogcnm, described 368 cardinal area discussed 303 compared with Mickwitzia monilifcra 368 Sil^honotreta verrucosa 367 discussed 367 general geographic and stratigraphic distribution tabulated 99 type specimen figured PI. LXIII, flg. 7d hera, see AcrotUelc subsidua. HSrault, France, localities in 342, 342a Herefordshire, England, localities in 304, 304a-g Herjeadalen, Sweden, locality in 320w Beterorthis, classification of, by Uhich 308 no Cambrian representatives 320 Hicks, H., bibliographic references 18 species named for 756 Hicks, H. [Salter, J. W., and], bibliographic reference 23 Jiicksi, see BillingscUa. High Bridge, on Ausabie River, New York, locality at 338s Highgate Falls, Vermont, localities near 28, 87, 87', 319q Highgate Springs, Vermont, localities near 26, 319v, 319y highlandcnsis , see BilUngsdla. Highland Range, Nevada, localities in 30, 31u 62667°— VOL 51, pt 1—12 53 Hillsdale, Montana, localities near 150a, 153, 153a, 154, 165, 155a, 156a, 157, 158, 158a Hillsdale, New York, locality near 367 1 Himonmine, near Pioche, Nevada, locality at 333a Hinge line, defined 294 Hipparionyx, compared with Nisusia festinata 728 Hipponicharion matthewi, stratigraphic position of bowlder con- taining, discussed 454, 684 Hisinger, W., bibhographic reference IS Historical data 13-98 Hjulsta, Sweden, locaUty at 3207 Hobbs, W. E., bibliographic reference IS Hof, Bavaria, localities near 303c, 303f Hijganiis, Sweden, locaUty at 311p Hokes Bluff road, Alabama, locality on 139 Holden, Utah, locality near 33 1 HoU, H. B., bibhographic reference 18 Holland, T. H., acknowledgments 12, 665 HoUis Creek, Teimessee, locality on 117o Hollybush sandstone, in generaUzed section for England, Scotland, and Wales, listing species and locahties 135 HoUybush series (Upper Cambrian), locality in 304gr mentioned 559 Holly Gap, see Mount HoUy Gap. HoUywood Point, Newfoundland, locahty on 5t Holm, G., bibliographic reference 18 Holmia kjerulfl, association mentioned 598, 600 Holmia kjerulfl zone (Lower Cambrian), in generahzed section for Sweden, Denmark, Finland, and Norway, listing species and localities 146 locahtiesin 8v, 320o, 320x mentioned 473 HoJoceplialina, association mentioned 498 inflata, association mentioned 498 Hoist, N. Olof, acknowledgments 12 Holston River, Tennessee , locahties near 9a, 104 Homer, Oklahoma, locality near 12p Honaker limestone (Middle Cambrian), in generalized section for Teimessee, Georgia, and Alabama, listing species and localities 14' locahty in 2z' Honey Creek, Oklahoma, locahty on 12k Honey Creek, Texas, locality near 69 Hoosac Mountain, Eureka district, Nevada, locahty on 206a Horn, Oeland Island, Sweden, locaUty at 390m Hornet Spring, Spring Mountain Range, Nevada, locality at 7n Hot Springs, Colorado, locahties near 335a, 360b House Range, Utah, localities in 3s, 3t, 3w, 3x, 3y, 4, 8g, 81, 8k, lOy, lOz, lln-q, llv-y, 14v, 15b, 15c, 30c-e, 30g, 30h, 30j-n, 30n', 30o, 30w, 30y, 30z, 31q, 31s, 31t, 31v, 105t House Range section, Utah, in detail, listing included and corre- lated species and localities 153-158 Houston County , Minnesota, locaUty in 84a Howchin, Walter, acknowledgments 12 HoweU formation (Middle Cambrian), in detailed section in House Range, Utah, listing included and correlated species and localities 157-158 locaUties in 31s, 31v Hoyts quarry, Saratoga Springs, New York, locality at 76 Hradischt, Bohemia, locaUty at 303k Hudson, G. H., bibliographic reference 18 Hudson, Wisconsin, locahties near 79, 79', 79b, 79s, 328j Huene, F. von, bibliographic references IS genus named for 805 Buenella, described 805 cardinal area discussed 305 classification of 321, 326 compared with Cterkrfte 809 Syntrophia "99 evolution discussed 320 evolution of 317 general geographic and stratigraphic distribution of the species referred to 109 general stratigraphic distribution and number of Cam- brian species and varieties of Ill mentioned S07, 809 number of species of, in different types of sediment ... 160 oldest species 807 shell structure compared with that oiSyntropUa 300 834 CMIBRIAN BRACHIOPODA. HuencUa— Continued. spondylium discussed 307 type species " Syntrophia texana ■' 805 Ulrich on spondylium 308 abnormis, described 805 compared with Hucnclla biUingsi 806 HuencUa oricntalis 808 Hucnclla texana 808 HucneUa texana Ueviusculus 808 SyntTophia campbelli S02 general geographic and stratigraphic distribution tabu- lated 109 muscle scars discussed 313 shell section figured text fig. 13, p. 299 shell structure compared with that of Syntrophia later- alis 300 spondylium discussed 333 type specimen figured PI. CIII, tig. 2a vascular markings discussed 312 hillingsi, described 806 general geographic and stratigraphic distribution tabu- lated 109 type specimen figured PI. CII, fig. 5a ethcridgei, described 807 general geographic and stratigraphic distribution tabu- lated 109 type specimen figured PI. LXXXIX, fig. 9 lesleyi, described 807 general geographic and stratigraphic distribution tabu- lated 109 type specimen figured text fig. 75 B, 807 orientalis, described • 808 general geographic and stratigraphic distribution tabu- lated 109 type specimen figured PI. CIV, fig. 3 texana, described 808 compared with Huenella abnormis 806 Huenella billingsi 806 HueneUa lesleyi 807 Huenella oricntalis 808 Syntrophia campbelli 802 general geographic and stratigraphic distribution tabu- lated 109 surface ornamentation discussed 303 type specimen figured PI. CIII, fig. 1 texanalxviusculus , described -. 808 general geographic and stratigraphic distribution tabu- lated 109 type specimen not figured. vermontana, described 809 general geographic and stratigraphic distribution tabu- lated 109 type specimen figured text fig, 76, 809 Hulushan, China, localities on C3, C62 humillima, see Lingulella. Hunueberg, Sweden, locafities on 320r, 321q, 321r, 390f, 390n hunnebcrgcTisis, see ProtorfMs. Hyatt, Alpheus, acknowledgments 12 HykOj Nevada, locality near 216a Hyolithes, association mentioned 359, 539, 788 compared with A crolhyra 7I6 americanus, association mentioned 613 cf. communis, association mentioned 328 Hyrum, Utah, localities east of .31c-e, 31h, 311-n, 54a-p, 54y, 55h, 55n, 185z ida, see Elkania. Idaho, Cambrian species of, listed 114-119 localities in • 4y, 5a-c, 5h, 54S-X, 55c, 55d, 56f, 56g, 59f, 59g, 163, 322, 322a species and localities correlated w ith those of Utah 148-153 idakoensis, see A crotreta. idahoensis alta, see Acrotreta. idahoensis sulcata, see Acrotreta. Iddings, J. P., species named for 780 iddingsi, see Eoorthis. Ijora (Ischora?) River, St. Petersburg, Russia, localities on.. 336a, 336n Ilgast, Esthonia, Russia, localities at 395b, 395i, 395o Inartieulata, distribution in Cambrian strata 316 Inarticulate brachicpods, defined 294 either corneous or chitinous 296 inchoans, see Acrotreta. India, Cambrian species of, listed 121-122 localities in I5r, 357, 357a-d Indian Creek, Nevada, locality near I4in indianola, see Eoorthis. Indian River valley. Cape Breton, Nova Scotia, localities in lOp, lOp', lOp", lOq. 13d, 13d', 13d", 13e-g, 13k, 131, 131', 13m, 13n', 13n", 13p, 13p', 13t, 13t', 13t", 344, 344a-d, 344f-i, 344k-m, 344o, 372f See also Dugald, Gillis, and Gregwa brooks. Indian Spring, Nevada, locality near 7n Indian View, New York, locality on 185a inflata, see Acrotreta. inflatus, see Obolus. ingricus, see Obolus apollinis. ino, see Lingulella. insignis, see Trematobolus. insonSy see Lingulella. insula, see Lingulella atava. Interior continental province, Cambrian species in, listed 114^119 Interlocking plications, discussed 303 intermedia, see Acrothclc. Intestine, shown in figure 374 Inyo County, CaJifomia, localities in 7, 8b, 14 1, 14n-p, 53, 53a, 176, 176a, 178a, 312, 312a Inyo Range, California, locality in I76a inyocnsis, see WimaneUa. iolc, see Lingulella. Iowa, Cambrian species of, listed 114^119 localities in 341, 341a note on stratigraphic position of localities in 159 "Iphidea," mentioned 344,359 notes on use as a generic name 334 "sculptilis,*' type of Micromitra 333 Iphidella, derivation 359 notes on use as a subgeneric name 334, 359 used as a subgenus , 336, 359 {Iphidella), see Micromitra {Iphidella). iphis, see Obolus ( Westonia). Ireland, Cambrian species of, listed 120-121 localities in 317, 317a Irene, see Lingulella. iris, see Lingulella. Iron County, Missouri, localities in lid, 369b Iron Mountain, Michigan, locality at 330b Iruya, Argentina, locahty at 389d Ischora River, see Ijora River. Isenhof , Esthonia, Russia, localities at 395e, 395 1, 395r, 395u ismene, see Obolus. isse, see Lingulella. Iswos, St. Petersburg, Russia, locality at 396k Italian Ranch foothills, Nevada, locality near 7j Italics, explanation of use of, in localities 328 Italy, localities in 354, 354a-f See also Sardinia. Itfer limestone, in generalized section for Russia 143 Ivangorod, Russia, see Narwa. Jackson Creek, Teton Moimtains, Wyoming, localities on 4e, 4m-o Jackson Lake, Teton Mountains, Wyoming, localities near.... 4e, 4m-o Jackson mine. Eureka district, Nevada, localities near 62a, 202 Jacksonville road , Alabama, locality on 146 Jaggowal, Esthonia, Russia, locality at 9d Jaggowal Brook, Esthonia, Russia, locality on 396u Jamburg, St. Petersburg, Russia, locality at 395z James, J. F., bibliographic reference 18 subgenus named for 731 {Jam.esella), see Nisusia (Jamesella). Jiimtland. see Jemtland. Jefferson County, Alabama, localities in 56o, 56q, 56u, 139a, 140 Jefferson County, New York, localities in 185, 185a, 338j Jefferson County, Tennessee, locahty in 119 Jefferson County, Wisconsin, localities in 97a, 97c, 328a Jegelecht, Esthonia, Russia, localities near . . , 395, 395a, 395g, 395h, 395iii, 395u Jemtland, Sweden, localities in 3201, 320t, 320w Jeremejew, P. W., bibliographic reference 18 Jerrestad, Sweden, localities at 310u, 310x Jewe limestone, in generalized section for Russia, listinc species and localities , 143 "Jewesche Schicht" (Ordovician), locality in 337e INDEX. 835 Jinec, Bohemia, localities at 345b, 3451 Joa, Esthonia, Russia, localities at 395, 395g, 395m johannensis, see EooTtMs. Johannian (Middle Cambrian), generalized section of,listing species and localities 131-133 localities in 131, 13r, 308c Jolmson Creek, Bighorn Momitains, Wyoming, locality on 302y Jomala, Aland Island, Finland, localities in 311e, 311t Jordan's, Cherokee County, Alabama, localities near 93, 93n, 93o Juab Coimty, Utah, localities in 14t, 15d, 15x, 33d, 34g, 34i, 34n, 34s, 329d Jujuy , Argentina, locality in 389b Jutana, Salt Range, India, loeaUty at 357a K&gerod, Sweden, locality near 309e Kakkomaggi, Esthonia, Russia, locaUty at 396t Kalmar quadrangle, Sweden, locaUties in 310f, 390a, 390d, 390h Kamenna hurka, localities and species in zone of, listed 124 Eamenna hurka zone (Lower Cambrian), localities in 345i, 345j Kanab Canyon, Arizona, locaUty in 75 kanabensis, see Nisusia (Jamesella). KarAsek, Bohemia, locality on brook of 345a Karpinsky, A. P., bibliographic reference 19 K^tveit, Norway, locality at 323q Kayser, E., species named for 782 Kayser, F. H. E., bibhographic references 19 kayseri, see Eoorthis. KeedysviUe, Maryland, localities near 47e, 47f Eeeseville, New York, localities near 338r, 338t, 367f Keith, A., bibliographic references 19 Kelleys Island, Newfoundland, locality on 314a Kemp, J. F., species named for 621 kempanum, see Trematobolus. Kenlochewe, see KinJochewe. Kennebecasis Bay, New Brunswick, localities on 2s-u, 2s, 308g Ketona, Alabama, locality at • 56q Keyes, C. R., bibliographic reference 19 Keyes Valley, Nevada, locality in 221 KeyserUng, A. de, genus named for 628 Keyserlingia, described 628 cardinal area discussed 305 classification of 321, 324 compared with Schizotreta elUptica 628 Siphonotreta unguiculata 628 evolution of 317 general geographic and stratigraphic distribution of the species referred to 105 general stratigraphic distribution and number of Cambrian species and varieties of m number of species of, in different types of sediment . . . 160 pedicle tube discussed 315 type species " Orbicula buchi "... 628 buchi, described 628 discussed 628 general geographic and stratigraphic distribution tab- ulated 105 old-age characters discussed 315 type specimen not figured. "panderi" discussed 369 Khewra, see Kiura. Khussak, Salt Range, India, locality at 15r Khussak group (Middle Cambrian), localities in 357, 357a-d kichouensis, see Eoorthis. Kichou limestone (Middle Cambrian), locaUties in. . C37, C71, C72, C75 Kichou limestone (Upper Cambrian), locality in C74 Kimbrel, Alabama, locality near. 90c Kinderhook Creek, localities on 29, 338b Kinderhook quadrangle. New York, localities in 32a, 44a, 44b, 338b King, Wilham, bibliographic references 19 terminology of 292 Kingena, mentioned 506 Kings County, New Brunswick, localities in 2y, 300, 301f , 308d Kinlochewe Hotel, Loch Maree, Scotland, localities near 316c, 316d KinnekuUe, Sweden, localities at 320ni, 390p Kiokiapu, China, locaUty near C57 Kisinling limestone (Middle Cambrian), locaUty in C32 Kiulung group (Middle Cambrian), locaUties in 01, C2, C4-7, C9, CIO, C12, C57, C62, 063 Kiulung group (Upper Cambrian), localities in 061, 064 Kiura (Khewra), Salt Range, India, localities at 357, 357c, 357d i kiurensis, see Lingulella. Kiviks Esperod, Sweden, locaUties at 310y, 320k Kjerulf, T., bibUograpliic references 19 Kiittberget, Sweden, locality at '. 390 1 Ejiox County, Tennessee, localities in lOa, 10b, 12, Ua, 18, 106, 106a, 107, 107a, 107b, 107o, 107u, 118, 374 Knox dolomite (Upper Cambrian), in generaUzed section for Tenn- essee, Georgia, and Alabama, listing species and locaUties. 147 locaUties in I2q, 93, 93a, 93o, 105, 107o, 107u KnoxviUe, Tennessee, localities near 10a, 10b, 12, 14a, 18, 106, 106a, 107, 107a, 107b, 107o, 107u, 118, 374 Koken, E . F. R ., bibhographic reference 19 Konigsberg, East Prussia, localities east and south of... 386a, 386b, 386i Konlgshof, Bohemia, locaUty at 303 ICoporje, St. Petersburg, Russia, locality at 336o Kopparberg, Sweden, locaUties in 8y, 310n, 390 1 Kosh Brook, Esthonia, Russia, locality on 396s Krekling, Norway, locaUties at 3231, 323r, 324b, 324c Kristiania, see Christiania. Kristianstad, seeChristianstad. Kruschna hora, Bohemia, locaUty at 3031 Kucker limestone, in generaUzed section for Russia, Usting species and locaUties 143 Kunda Brook, Esthonia, Russia, locaUties on 396v, 396w ICimitz, Pskow, Russia, locaUty at 336p Kusal, Esthonia, Russia, locality at 337a ICuthan, Wilhelm, species named for 733 kuthanijSee Nisusia (Jamesella). Kutorga, S. S., bibhographic reference ig genus named for 579^ 530 species named for 592 kutorgai, see Acrotreta. KutorgiTia, described 579 cardinal area discussed 304 cardinal process discussed 306 classification of 321, 323 compared with Micromitra (Paterin-a) labradorica 333 Obolella 552 Obolus 582 Volborthia 366 evolution discussed 319 evolution of 317 general geographic and stratigraphic distribution of the species referred to 104 general stratigraphic distribution and number of Cam- brian species and varieties of no mentioned 334^ 357^ 553 muscle scars discussed 313 number of species of, in different types of sediment 160 reference to, oi Protortkis latourensis discussed 742 shell structure , 297 stratigraphic position mentioned 313 surface ornamentation discussed 303 teeth in discussed 532 cingulata, described 539 articulating processes discussed 3o7 association mentioned 349 compared with Kutorgina granulata 583 Kutorgina peculiaris 533 Kutorgina perugata 534 Kutorgina sardiniaensis 534 Kutorgina sp. undt 534 Micromitra (Paterina) prospcctcnMs 353 confused with Micromitra {Paterina) phillipsi 352 Rustella edsoni 323 general geographic and stratigraphic distribution tabulated 104 shell sections figured text figs. 3 and 8, 299 teeth in discussed 532 type specimen not figured. granulata, described 532 general geographic and stratigraphic distribution tabulated 104 surface ornamentation discussed 302 type specimen figured PI. V, figs. 5 and 5a ^^labradorica swantonensis ," type of Micromitra {Paterina) . , 344 pecuUaris, described 583 general geographic and stratigraphic distribution tabulated 104 type specimen figured PI. V, fig. 2 836 CAMBRIAN BRACHIOPODA. Kutorgina pcrugata, described 5S3 general geographic and stratigraphic distribution tabulated... 104 type specimen figured PI. V, fig. 3c ptcrlncoidcs, discussed 742 sardiniacnsis, described 584 general geographic and stratigraphic distribution tabulated 104 type specimen figured PI. V, fig. 4 sp. undt., described 584 general geographic and stratigraphic distribution tabulated 104 type specimen not figured. ? sp., stratigraphic position of bowlder containing, dis- cussed 454,684 Kutorginacea, classification of 321, 323 distribution in Cambrian strata 316 genera and species referred to, described 579-585 Kutorginidffi, classification of 321, 323 distribution in Cambrian strata 316 genera and species referred to, described 579-584 general stratigraphic distribution and number of Cambrian genera and species of 112 • number of Cambrian genera and species of 112 number of genera and species in monograph 113 Kwagunt Valley, Arizona, localities in 73, 73b Labrador, Cambrian species of, listed 114-119 localities in 392a, 392c, 392 1 note on stratigraphic position of localities in 143 Ubradorica, see Mkromitra (Paterina). lahradorica orientalis, see Micromitra (Paterina). labradorica swantonensis, see Micromitra (Paterina). labradorica utaftensis, see Micromitra (Paterina). La Crosse, Wisconsin, locality at 78d La Crosse County, Wisconsin, locality in 78d Ladoga, St. Petersburg, Eussia, locality near 336q See also Lake Ladoga and Staroja Ladoga. ladogensis, see Uehnerscnia. Laesaa, Bomholm, Denmark, localities at 16j, 16k, 334e Isevis, see Acrotlicle subsidua, Lingulella, and Protarthis. Ixvis gra-ndis, see TAngulella. Iseviusculus, see Eoorthis iciehitaensis and Huenella texana. Laggan, Alberta, localities near 35d, 35e La Grange Mountain, near Red Wing, Minnesota, locality at 113 Lake Champlain, localities near 319j, 319b See also Vermont. Lake City, Mirmesota, locality near 131 Lake Ladoga, St. Petersburg, Russia, localities near 3361, 337k Lake Louise, Alberta, localities near 35d, 35e Lake Louise shale (Lower Cambrian), detailed section listing species and localities 130 locahty in 35d LakeMjosen, Norway, locaUties near 8v, 323t, 32i Lake Pepin, Minnesota, localities near 97, 97x, S97x, 339c Lakeview Ranch, north of Brigham, Utah, localities near 32p, 32x, 33j, 34q, 541i, 64q, 54r, 55e, 105x "Lakhmina," classification of 566 discussed 6G5, 666 Hall and Clarke on development of 309 platform mentioned 309 "linguloides," coiapared with Neobolus warthi 566,567 discussed 566, 667 Lamansky, Wl., bibliographic reference 19 lamborni, see Obolus. lamborni minimus, see Obolus. Lamellge, discussed 296 lamellosus, see Obolus (Wcstonia). Lamotte, see Mine Lamotte. Lamotte sandstone, in generalized section for Missouri 137 Lampasas County, Texas, locality in 14e, 14q Lancashire, England, locality in 304n Lancaster County, Peimsylvania, localities in 12v, 346a Lance Cove, Great BgUe Island, Newfoundland, locality at 114b Lander, Wyoming, locality near 302e Landis Valley, Pennsylvania, locality in 346a Landusky, Montana, locality near 302z Langston Limestone (Middle Cambrian), apparent equivalent of, in detailed section In House Range, Utah, listing included species and localities 1 58 Langston limestone— Continued. in detailed section in Blacksmith Fork, Utah, listing in- cluded and correlated species and localities 152 locaUties in 5b, 30e1, 54s, 322a Lanna, Sweden, locality in 320v Lansdo^vne, Ontario, locality in 392d L'Anse au Loup, Labrador, locality at 392a Lansing, Iowa, locality near 341 Lansingburg, New York, localities at 27a, 367b Last Chance copper mine, Grand Canyon, Arizona, locality at 17c Last Chance Gulch, near Helena, Montana, locality in 302s lata, see Acrothde matlhewi. Lateral areas, defined 294 Lateral septa, shown in figure 374 lateralis, see Syntrophia. latourcnsis, see Pro'orthis. Lauzon of Logan (Ordo™ian), locality in 220a Lava Canyon, Arizona, locality in 74c leda, see Obolus tctonensis. Leeds, Ontario, localities in 392b, 392d, 392e Leetz, Ksthonia, Russia, localities near 396a, 396n Leitches Creek, see Upper Leitches Creek. Lemland, Aland Island, Finland, locality in 311t Lena River, Siberia, locality on 347 lens, see Lingulella and Obolus (Palxobolus) bretonensis. Icnticularis, see Orusia. lenticularis atrypoides, see Orusia. Icnticularis lyncioides, see Orusia. Leon, Spain, locality in 350 leos, see Lingulella. lepsis, see Lingulella. Leppiko, Esthonia, Russia, localities at 396a, 396n Leptsena, reference to, of Protorthis hunnebergensis discussed 741 dccipiens, compared with Eostrophomena elegantula 796 "melita," discussed 777 rliomboidalis, compared with Keyserlingiu buclii 630 LeptffinEe, compared with Nisusia (Jamesella) pcllico 735 Leptembolon, compared with Schmidtia 378 mentioned 437 (Leptembolon), see Lingulella (Leptembolon). Xep;o6oZ«5, characterized and species referred to or allied to listed. 472 compared with Lingulella 472, 603 '^atavus," mentioned 472 '^ataims insulx," mentioned 472 "atamis tritavus," compared with Lingulella torrentis 635 mentioned 472 "colUcia," mentioned 472 "collicia colUs," mentioned 472 "fiumenis," mentioned 472 "gemmulus," discussed 499 mentioned 472 "grandis," discussed 503 "insulse," compared with Lingulella flumenis 501 "cf. linguloides," mentioned 472 "torrentis," mentioned 472 Lesley, J. P., species named for. 807 lesleyi, see Huenella. Leuchtenberg, M. H. von, bibliographic reference 19 Levis, see Point Levis. Levis shales (Lower Ordovician), locality in 319a levisensis, see Acrothde. Le^yisand Clark County, Montana, locaUties in.. 4ii, 9k, 9in, 302s, 340a Liaotung, China, locaUties in 332, 332a Liberty, Bear Lake Cotmty, Idaho, localities near 65c, 56f, 56g, 59f, 59g, 163, 322 Libetschov, Bohemia, locaUty at 303 1 Lidkoping, Sweden, locaUties in 320m, 320p Lieben, Bohemia, locality at 303m Likkat, Esthonia, Russia, locality near 396s LiUidken, Sweden, locality at 320 1 Limestone, number of genera and species identified from 160 Limestone and sandstone, number of genera and species common to both 160 Limestone and shale, number of genera and species common to both 160 Limestone, shale, and sandstone, number of genera and species common to all three 160 limoensis, see Acrofreta uplandica. Limon Island, near Gefle, Sweden, localities on 311m, 311n INDEX. 837 Lincoln County, Nevada, localities in ^^t In, 14m, 30, 31, 31a, 31u, 216a, 313g, 333, 333a, 333b Lindstrom, G. , species named for 596, 757 lindstromi, see BiTlingsdla and Obolella. lineolata, see Lin^ulclla. Lingula , association mentioned 7SS classification 310 compared with Lingulella 376, 471, 472, 473 LiTigulellaiLeptembolon) .*. 541,5_42 Obolzis , 373-376 development of platform in 309 evolution discussed 319 mentioned 297,386,407,471,482,508,512,532 shell structure of, compared with that of Obolus 296 vascular markings mentioned 311 ^'acuminata," mentioned 386 type of Lingulella (Lingulepis) 474 aTiatina, compared with Lingulella acutangula 474 compared with Lingulella (Leptembolon) lingulx- formis 543 figured 374 ''antiqua,'- compared \\ith Obolus belli 386 "attenuata," compared with Lingulella 473 compared with Lingulella bornemanni 483, 484 Lingulella heberti 506 "aurora,"' type of Obolus ( IV estonia) 37S. 450 cf . billingsiana, discussed 503 cincta, surface ornamentation discussed 301 "? coTTugata," disciassed 515 "cuneata," compared with LiTigulella acutangula 476 "davisi,'* type oi Lingulella 469 *' ? dawsoni," discussed and original description copied . . . 497, 498 eximia, surface ornamentation discussed 301 "exunguis," mentioned 531 *'? favosa," type ot Obolella {Glyptias) 599 "feistmanteli" mentioned 332 lesueuri, compared with Delgadella lusitanka 560 " ? monilifera," type species of Mickwitzia 329 " ? OTdoviceTisis ," discussed 515 "petalon," generic and specific reference discussed 403 " pinnaformis ," discussed 547,548 "prima/' mentioned 386 " ? producla," discussed 515 rouauUi, compared with Mickwitzia sp. undt 332 nnentioned 584 *' ? warthi," discussed and compared with Lingulella kiuren- sis 511 "(?) sp. Matley," discussed 703 "sp. Siemiradzki," discussed 531 Lingula ^a^, in generalized section for England, Scotland, and Wales, listing species and localities 135-136 mentioned 541 Lingula flags, Lower (Upper Cambrian), localities in 318c, 318g, 366d-n Lingula flags, Middle (Upper Cambrian), localities in 304g, 366a Lingula flags, Upper (Upper Cambrian), localities in 305d, 318, 318a, 318b, 318s-v, 366s Lingula or Lingulella sp. Linnarsson, discussed 499 lingula; for mis, see Lingulella (Leptembolon). Lingulasma, classification 310 Hall and Clarke on development of 309 mentioned 297 platform mentioned 309 schucherti, classification of 310 intermediate between Obolus {Fordinia) and Dino- bolus 310 Lingulella, described 468 cardinal area discussed 304 classification of 321, 323 compared with "Euobolus" 378 Leptobolus 503 Lingulella {Lingulepis) 544, 545 Lingulella (Lingulepis) acuminala 544 Obolus and Lingula 376 Obolus (Lingulobolus) 432 Obolus (Schmidtia) 442 development of 309 evolution discussed 319 evolution of 317 im^w/eZ^a— Continued, general geographic and stratigraphic distribution of the species referred to 101-103 general stratigraphic distribution and number of Cam- brian species and varieties of 110 generic separation from Obolus discussed 471-472 Hall and Clarke on development of 309 Lower Cambrian species of, discussed 472-473 mentioned 379, 386, 388, 401, 414, 474, 484, 489, 490, 495, 500, 503, 508, 511, 527, 532, 539, 541, 547, 557, 558, 560, 590, 604 muscle scars discussed 312 number of Ordovician species and varieties of 113 number of species of, in different types of sediment . . 160 oldest species 530 platform discussed 310 relative position of vascular sinus in species of 377 stratigraphic distribution discussed 473 subdivision of, on basis of outlines of ventral valve 470 surface ornamentation discussed 302 type species " Lingula davisi" 469 umbonal muscle mentioned 313 vascular markings discussed 311 young shells more circular in outline than adult shells. . 473 acutangula, described 474 compared with Lingulella ampla 477,478 Lingulella buttsi 454 Lingulella clarkei 485 Lingulella cuneola 488 Lingulella davidsoni 489 Lingulella grandis 503 Lingulella isse 510 Lingulella lineolata 516 Lingulella nutJiorsti 473 Lingulella perattenuata 524 Lingulella radula 529 Lingulella schucherti 472 Lingulella tarpa 535 Lingulella {Lingulepis) acuminata 546 Lingulella (Lingulepis) robcrti 557 Obolus 471 Obolus apollinis 472 Obolus lamborni 394,395 Obolus sclwyni 413, 414 Obolus ( Wes(onia) aurora 452 Obolus ( Westonia) ella 456 Obolus ( Westonia) euglyphus 461 Obolus ( Westonia ) finlandensis 462 Obolus ( Westonia) rogersi 464 general geographic and stratigraphic distribution tab- ulated 101 grouped on the basis of the outline of the ventral valve. 470 muscle sears discussed 312 type specimen not figured. platform mentioned 310 visceral area (splanchnocoele) characterized 470 " ? affinis,'' iypQ oi Obolus (Lingulobolus) 378,431 agnostorum, described 476 general geographic and stratigraphic distribution tab- ulated 101 type specimen not figured. ampla, described 477 compared with Lingulella oweni 523 Lingulella phaon 525 Lingulella pogonipensis 526 Lingulella (Lingulepis) starri 559 Obolus lamborni 394 Obolus ( Westonia) aurora 452 Obolus ( Westonia) ella 456 Obolus ( Westonia) notchensis 463 Obolus ( Westonia) stoneanus 465 general geographic and stratigraphic distribution tab- ulated 101 type specimen figured PI. XXVIII, fig. 1 visceral area (splanchnocoele) characterized 470 arguta, described 478 compared with Lingulella iris 509 general geographic and stratigraphic distribution tabu- lated 101 type specimen figured PI. XXIV, fig. 5 838 CMIBRIAN BKACHIOPODA. LingukUa atava, described 479 compared with Lin^ulella atava insulx 480 LingulcJla cania 485 colUcia 486 flumenis 501 torrcntis 535. 536 confused witli LingulcUa {L'niguli:pis)gregwa 479,480 general geograpliic and stratigrapliic distribution tabu- lated 101 t>-pe specimen figured PI. XXXV, flg. 5 atava insuls:. described 4S0 general geographic and stratigraphic distribution tabu- lated 101 type specimen figured PL XXXV, flg. S auga, described ^^0 general geographic and stratigraphic distribution tabu- lated 101 grouped on the basis of the outline of the ventral valve 4™ surface ornamentation characterized 470 type specimen figured PI- XXIV, flg. 6b beiio, described ^1 compared with LiTigulella arguta 479 Lingulella UllingsiaTm .' 483 LiTiguleUa 'kiuTeims 511-512 Lingulella lem 513 LiTtguleUa lepis 514 general geographic and stratigraphic distribution tabu- lated 102 grouped on the basis of the outline of the ventral valve. 470 species confused with 481, 482, 487,513 type specimen figured PI- XIX, flg. 2h iellula, described ^2 compared with Lingulella arguta 479 Lingulella billimisiana 483 LingukUa prima 527 Obolus rcfulgens 410 general geographic and stratipaphic distribution tabu- lated 102 type specimen figured PI. XIX, flg. la billingsiana, described 483 compared with Lingulella ampla 478 Lingulella bellula 482 general geographic and stratigraphic distribution tab- ulated 102 type specimen figured PI. XXIX, flg. 3a bornemanni, described 483 general geographic and stratigraphic distribution tabulated 102 type specimen flgured Fl. XXX, fig. 18 buttsi, described 484 general geographic and stratigraphic distribution tabulated 102 type specimen flgured PI. XXIX, flg. 4 "cxlata," discussed C04 cania, described 484 compared with Lingulella atava 480 Lingulelhi atava insulx 480 Lingulella manticula 518 Lingulella ora 522 Lingulella upis 538 confused with Lingulella (Lirtgulepis) gregwn 485 general geographic and stratigraphic distribution tabulated 102 reference to Leplobolus suggested 472 type specimen flgured PI. XXXV, flg. 3 cedens, described 485 general geographic and stratigraphic distribution tabulated 102 type specimen figured PI. XXX, fig. 8 clarkei, described 485 general geographic and stratigraphic distribution tabulated 102 type specimen figured tJxt flg. 42B 486 collicia, described 486 compared with Lingulella atava 480 Lingulella cania 485 LingukUa flumenis 501 Lingulella ora 522 Lingulella upis 538 Lingulella colUcia — Continued. general geographic and stratigraphic distribution tabulated 102 type specimen flgured PI. XXXV, fig. 1 "collicia co/?/s." compared with Lingulella collicia 486 concinna, described 486 compared with Lingula 319 Lingulella bella 482 Lingulella lens 513 Obolus acadicus 380 confused with Lingulella bella 481, 482, 487 general geographic and stratigraphic distribution tab- ulated 102 type specimen flgured PI. XXXIII, flg. 2d " f curaeato," discussed 503 cuneola, described 488 compared with Lingulella acuiangula 476 general geographic and stratigraphic distribution tab- ulated 102 type specimen figured PI. XXVII,_flg. 7 damesi, described , 489 compared with Obolus chinensis 387 Obolus prindlei 409 general geographic and stratigraphic distribution tab- ulated 102 generic reference changed 489 type specimen figured PI. XXXIX, fig. Sa davidsoni, described 489 general geographic and stratigraphic distribution tab- ulated 102 type specimen flgured PI. XXXII, flg. 1 davisi, described - 489 compared with Lingula 319 Lingulella bella 482 Lingulella cedent 485 Lingulella heberti ' 506 Lingulella kiurensis 512 Lingulella wirthi 541 Lingulella (Lingulepis) exigua 552,553 Obolus prindlei 379 Obolus (Schmidtia) celatus 472 Obolus (Westonia) ella 456 general geographic and stratigraphic (listribution tab- ulated 102 grouped on the basis of the outline of the ventral valve. 470 type specimen not figured. "cf. davisi," mentioned 499 "cf. davisii Kayser," discussed 490 delgadoi, described 491 discussed 560 general geographic and stratigraphic distribution tab- ulated 102 generic reference mentioned 473 type specimen figured PI. XXIX, fig. 6 desiderata, described 492 compared with Lingulella mantilla 517 Lingulella similis 533 Lingulella wanniecki 539 Obolus prindlei 409 general geographic and stratigraphic distribution tab- ulated 102 stratigraphic distribution and possible specific differ- ences in, mentioned 473 type specimen figured PI. XX, fig. 4 dubia, described 494 confused with Obolus (Westonia) ella 495 general geographic and stratigraphic distribution tab- ulated 102 platform mentioned 310 type specimen figured PI. XXIV, fig. 4 ellsi, described 495 general geographic and stratigraphic distribution tab- ulated 102 type specimen figured PI. XIX, fig. 3 ferruginea, described 496 compared with Lingulella bellula 482 Lingulella buttsi 484 Lingulella delgadoi 491 LingukUa desiderata 492 Lingulella ellsi 495 INDEX. 839 LtTiguMlaferruginea — Continued. compared with Lingulella cf. ferruginea. 500 Linguhlla gTanviUeiisis 504 LinguUlla lepis 514 Lingulella linnarssoni 516 Lingulella nichoJsoni 522 LinguleUa prima 527 Lingulella primseva 527 Lingulella sigrmta 532 Obolus/ragilis 393 Obolas prindlei 409 general geographic and stratigraphic distribution tab- ulated 102 platform men tioned 310 reference to Leptobolus suggested 472 stratigraphic position in Europe and America com- pared, -with lists of associated species 498 type specimen figured PI. XXIX, fig. 2b ef.ferruginea, described 500 general geographic and stratigraphic distribution tab- ulated 102 type specimen figured PI. XXX, fig. 4 ci.ferrugin^a Kayser, discussed 499 fenuginea ovalis, discussed 497 flumenis, described 500 compared with Lingulellaora 522 LinguleUa upis 533 general geographic and stratigraphic distribution tab- ulated 102 type specimen figured PI. XXXV, fig. 6 fTarikUneTisis, described 501 general geographic and stratigraphic distribution tab- ulated 102 type specimen figured PI. XXVI, fig. 3 fuchsi, described 502 general geographic and stratigraphic distribution tab- ulated 102 type specimen figured PI. XXXIX, fig. 3 "genei," discussed 495 grandis, described 502 compared with Lingulella auga 481 Lingulella biUingsiaTuz 483 general geographic and stratigraphic distribution tab- ulated 102 type specimen figmed PI. XXX\'III, fig. 2b granulfta (Phillips), compared with Lingulella heberti 506 granvillensis, described 504 cardinal area aiscussea 303, 304 compared with LinguleUa delgadoi 491 LinguleUa desiderata 492 LinguleUa franklinensis 502 Obolus prindlei 409 Obolus (Lingulobolus) affinis 431 Obolus (Schmidtia) eelafus 471 general geographic and stratigraphic distribution tab- ulated 102 platform mentioned 310 type specimen figured Pi. XXII, fig. 1 vascular markings discussed 31I of. granviUen^is Matthew, discussed 499 519 hayesi, described 505 compared with Lingulella phaorj 525 Obolus cyane 3S9 Obolus ( Westonia) wgeTsi 464 general geographic and stratigraphic distribution tab- ulated 102 type specunen figured Pl. XXV, fig. lb visceral area (splanchnocoele) characterized 470 lieheTti, described 5O5 general geographic and stratigraphic distribution tab- ulated 102 type specimen figiu-ed PI. XXXIX, fig. lib heleTm, described " g06 cardinal area discussed 304 general geographic and stratigraphic distribution tab- ulated 102 may equal Obolus mcconnelli in part 396 type specimen figured Pi. XXIV, fig. 3a Lingulella f humillima, described 507 general geographic and stratigraphic distribution tab- ulated 102 type specimen figured PI. XXX, fig. 12 ino, described 507 compared with Obolus sinoe 415 general geographic and stratigraphic distribution tab- ulated 102 platform mentioned 310 type specimen figured PI. XXVI, fig. 4 ? insoms, described 508 general geographic and stratigraphic distribution tab- ulated 102 type specimen figured PI. XXXII, fig. 2o iole, described 50s compared with Lingulella desiderata 492 Obolus cyane 389 general geographic and stratigraphic distribution tab- ulated 102 type specimen figured PI. XXVII, fig. 5 irene^ described , 508 general geographic and stratigraphic distribution tab- ulated 102 type specimen figured PI. XXVU, fig. 6 iris, described 509 general geographic and stratigraphic distribution tab- ulated 102 type specimen flgm:ed PI. XXVII, fig. 2 isse, described 509 compared with Lingulella pogonipensis 526 Lingulella wanniecki 538 general geographic and stratigrapliic distribution tab- ulated 102 stratigraphic range discussed and compared 510 type specimen figured PI. XXXIX, fig. 4a Tziurefnsis, described 511 general geographic and stratigraphic distribution tab- ulated 102 type specimen figured PI. XXX, fig. 6 IxviSj described 512 cora.-p^YQ<\ vfith. Lingulella Izvis grandis 512 Lingulella lens 513 general geographic and stratigrapliic distribution tab- ulated 102 type specimen figured PI. XIX, fig. 4 Isevis grandis, described 512 general geographic and stratigraphic distribution tab- ulated 102 type specimen figured PI. XIX, fig. 4c lens, described 512 compared with Lingula 319 Lingulella bclla 482 confused with Lingulella bella 481, 482, 487, 512, 513 discussed ^ . 487 general geographic and stratigraphic distribution tab- ulated 102 type specimen figured PI. XXXin, fig. 1 leos, described 513 general geographic and stratigraphic distribution tab- ulated 102 type specimen figured PI. XXIV, fig. 2a visceral area (splanchnocoele) characterized 470 lepis, described 514 compared with Lingulella ferruginea 499 LinguleUa linnarssoni 516 Lingulella nicholsoni 522 general geographic and stratigrapliic distribution tal>- ulated 102 reference to Leptobolus suggested 472 type specimen not figured. Uneolata, described 515 compared with Lingulella franklinensis 502 Obolus ( Ti'estonia) euglyphus 462 general geographic and stratigraphic distribution tab- ulated 102 type specimen figured PI. XLVIII, fig. 2b "linguloides,^' discussed 498 linnarssoni, described 516 840 CAMBRIAN BRACHIOPODA. Lingulella Unnarssoni— Continued . general geographic and stratigraphic distribution tab- ulated 102 type specimen figured PI. XXX, fig. 14 "longovalis," discussed 536 figured 636 manticula, described 517 compared with Lingulella arguta 47S L'mgulcUa clarkei 4S5 Lingulella desiderata 492 Lingulella granvillcnsis 504 Lingulella ora 622 Lingulella similis 533 Obolus rotu-ndaius 411 general geographic and stratigraphic distribution tabulated 102 grouped on the basis of the outhne of the ventral valve. 470 type specimen figured PI. XX, fig. Ic visceral area (splanchnocoele) characterized 470 martinensis, described 518 compared with Lingulella ferruginea 498 Lingulella tumida 537 general geographic and stratigraphic distribution tabulated 102 outline of ventral valve characterized 470 type specimen figured PI. XXXVIII, fig. la minor f described 519 general geographic and stratigraphic distribution tabulated 102 type specimen figured PI. XXXVII, fig. 3 mosia, described 520 compared with Lingulella mosia oscedla 521 Lingulella? signata 532 Lingulella winona 540 Lingulella winona convexa 640 general geographic and stratigraphic distribution tabulated 102 grouped on the basis of the outline of the ventral valve. 470 type specimen not figured. mosia osceola, described 521 compared with Lingulella Uurensis 512 Lingulella randomensis 530 general geographic and stratigraphic distribution tabulated j02 type specimen figured pi. XVIII, fig. 2 Tianno, described 521 general geograpliic and stratigraphic distribution tabulated 102 grouped on the basis of the outline of the ventral valve. 470 surface ornamentation characterized 470 type specimen figured pi. XXIV, fig. la Tiathorsti, described 521 compared with Lingulella a^utangula 473 Lingulella heberti 5O6 Obolusf sp. undt. f 423 cardinal area discussed 3O4 general geographic and stratigraphic distribution tabulated 102 type specimen not figured. nicholsoni, described ^ 522 general geographic and stratigraphic distribution tab- ulated 102 type specimen figured pi. XXX, fig. 3 ora, described 522 compared with Lingulella upis 533 Lingulella wanniecki 539 general geographic and stratigraphic distribution tab- ulated 102 type specimen figured pj. XXXV, fig, 9 oweni, described 523 compared with Lingulella wanniecki 539 general geographic and stratigraphic distribution tab- ulated 102 type specimen figured Pl. XVIII, fig. 5b visceral area (splanchnocoele) characterized 470 "? paliformis, " compstved with Lingulella 473 perattenuata, described 523 compared with Lingulella cuneola 488 Lingulella mosia osceola 521 Lingulella similis 533 Lingulella perattenuata— Continaed. compared with Lingulella (Lingulepis) acuminata meeki 550 Obolus (Westonia) ella 456 general geographic and stratigraphic distribution tab- ulated 102 generic and varietal reference of form referred to from Texas, discussed 550 grouped on the basis of the outline of the ventral valve. 470 type specimen figured PI. XXI, fig. lb visceral area (splanchnocoele) characterized 470 phaon, described 525 compared with i ingulella cuneola 488 general geographic and stratigraphic distribution tab- ulated 102 outline of ventral valve characterized 470 type specimen figured PI. XXVI, fig. Ic "pinna/ormis," mentioned 648 pogonipcnsis, described £25 compared with Lingulella isse 610 general geographic and stratigraphic distribution tab- ulated 102 type specimen figured PI. XX, fig. 3 prima, described 526 general geograpliic and stratigrapliio distribution tab- ulated 102 type specimen not figured. ? primseva, described 527 general geographic and stratigraphic distribution tab- ulated 102 type specimen figured PI. XXXI, fig. 5a punctata, described 528 compared with Lingulella arguta 479 Lingulella manticula 617 discussed 517 general geographic and stratigraphic distribution tab- ulated 102 type specimen figmed PI. XX, fig. 9 visceral area (splanchnocoele) characterized 470 guadrilateralis, described 628 general geographic and stratigraphic distribution tab- ulated 102 type specimen figured PI. XXXIX, fig. 6 radula, described 529 compared with Lingulella bellula 482 Lingulella ferruginea 498 Lingulella ino 507 Lingulella martinensis 518 Lingulella nathorsti 521 Obolus cyane 389 Obolus fragilis 393 general geographic and stratigraphic distribution tab- ulated 102 type specimen figured PI. XLV,fig. Id visceral area (splanchnocoele) characterized 470 radula aspera, discussed 529 randomensis, described 530 general geographic and stratigraphic distribution tab- ulated 102 type specimen figured PI. XXI, fig. 5 rotunda, described 530 compared with Lingulella desiderata 492 Lingulella ellsi 495 general geographic and stratigraphic distribution tab- ulated 102 type specimen not figured. schucherti, described 530 cardinal area discussed 304 compared with Lingulella acutangula 472 general geographic and stratigraphic distribution tab- ulated 102 generic reference discussed 472 oldest species of genus 531 type specimen figured PI. XXI, fig. 6 siemiradzkii, described 531 general geographic and stratigraphic distribution tabulated 102 type specimen figured PI. XXXI, fig. 2 signata, described 532 general geographic and stratigraphic distribution tabulated 102 type specimen figured PI. XXX, fig. 11 INDEX. 841 LinguUXUi similis, described 532 compared with Lingulella desiderata 492 Lingulella leos 514 general geographic and stratigraphic distribution tabulated , 103 type specimen figured PI. XXI, fig. 2 visceral area (splanchnocoele) characterized 470 ? simplex, described 534 general geographic and stratigraphic distribution tabulated 103 t5T)e specimen not figured. tarpa, described 534 compared with Lingulella franklineTisis 502 Lingulella ino 507 general geographic and stratigraphic distribution tabulated 103 type specimen figured PI. XXIII fig. 2a texaTia, described 535 general geographic and stratigraphic distribution tal>ulated 103 type specimen figured PI. XLIX fig. 3a torrejitis described 535 general geographic and stratigraphic distribution tabulated 103 type specimen figured PI. XXXV, fig. 7 tripanlis, described 536 compared with Lingulella (Lingulepis) gregwa 556 Lingulella (Lingulepis) longinervis 556 Lingulella (Lingulepis) pumila 556 Obolus ? torrentis 418 general geographic and stratigraphic distribution tabulated 103 intermediate between Lingulella (LingvZepis) gregwa and Lingulella (Lingulepis) longin^rvis 556 type specimen not figured . tumida, described 537 confused with Lingulella (Lingulepis) gregwa 537, 554 general geographic and stratigraphic distribution tabulated 103 type specimen not figured. ' ' unguiculus ' ' mentioned 497 upis, described 538 compared with Lingulella wanniecki 538, 539 general geographic and stratigraphic distribution tabu- lated 103 type specimen figured PI. XXXVI, fig. 3 wanniecki, described 538 compared with Lingulella fuchsi 502 general geographic and stratigraphic distribution tabu- lated 103 type specimen not figured. welleri, described 539 general geographic and stratigraphic distribution tabu- lated 103 type specimen figured PI. XXXVIII, fig. 4 Winona, described 539 compared with Lingulella winona convcxa 540 general geographic and stratigraphic distribution tabu- lated 103 grouped on the basis of the outline of the ventral valve. 470 type specimen not figured. winona convexa, described 540 compared with Obolus pheres 408 general geographic and stratigraphic distribution tabu- lated 103 tj'pe specimen figured PI. XVIII, fig. 4a wirthi, described 541 compared with Lingulella cedens 485 general geographic and stratigraphic distribution tabu- lated 103 type specimen figured PI. XXX, fig. 7 zeus, described 541 general geographic and stratigraphic distribution tabu- lated 103 type specimen figured text fig. 45, 541 sp. undt. a, described 541 compared with Lingulella agnostorum 476 general geographic and stratigraphic distribution tabu- lated 103 type specimen figured PL XXX, fig. 13 Lingulella sp. undt. b, described 541 general geographic and stratigraphic distribution tabu- lated 103 type specimen not figured, sp. Kayser, discussed and compared with Lingulella davisi and L. ampla 490-491 "(?) sp. Matley," discussed 703 Lingulella (Leptembolon), described 541 characterized 473^74 classification of 321, 323 evolution discussed 319 evolution of ' 317 general geographic and stratigraphic distribution of the species referred to 103 general stratigraphic distribution and number of Cam- brian species and varieties of 110 may include Lingulella f insons 508 mentioned 378 number of species of, in difi'erent types of sediment . . 160 type species " Obolus (Leptembolon) lingulxformis'" 474 lin^ulEeformis, described 542 general geographic and stratigraphic distribution tabu- lated 103 type specimen not figured. lingulxfoTmis solidus discussed 543 Lingulella (Lingulepis), described 544 characterized 474 classification of 321, 323 compared with Botsfordia 602 Delgaddla 560 Lingulella 472 evolution discussed 319 evolution of 317 general geographic and stratigraphic distribution of the species referred to 103 general stratigraphic distribution and number of Cam- brian species and varieties of 110 mentioned 378, 471 , 488, 557, 558, 559, 560, 668 number of Ordovician species and varieties of 113 nmuber of species of, in different types of sediment. . . 160 reference to, of Lingulella (Lingulepis) acuminata meeki, discussed 550 relative position of vascular sinus in species of 377 stratigraphic distribution of species discussed 545 surface ornamentation discussed 302 type species " Lingula acuminata" 544 type species of, discussed 547, 548 young shells more elongate than adult shells 473 acuminata, described 545 compared with Lingulella bornemanni 483 Lingulella cuncola 488 Lingulella signala 532 Lingulella (Lingulepis) acuminata meeki 550 Lingulella (Lingulepis) acuminata sequcns 551 Lingulella (Lingulepis ) exigua 553, 555 Lingulella (Lingulepis) gregwa 555 Lingulella (Lingulepis) roberti 557 Lingulella (Lingulepis) rowci 558 Lingulella (Lingulepis) squamosa 559 Obolella chromatica 592 Obolus belli 386 Obolus rhea 411 Obolus sinoe 545 Obolus ( Westonia) rogersi 464 general geographic and stratigraphic distribution tabu- lated 103 type specimen figured PI. XL, fig. 1 acuminata meeki, described 550 compared with Delgadella lusitanica 560 Lingulella (Lingulepis) eros 551 general geographic and stratigraphic distribution tab- ulated 103 type specimen figured PI. XLI, fig. 2 acuminata seguens, described 551 general geographic and stratigraphic distribution tab- ulated 103 type specimen figured te.xt fig. 46A, 551 ocumiTiata weeksi, merely an error in spelling 550, 551 eros, described 551 general geographic and stratigraphic distribution tab- ulated 103 type specimen figured PI. XXXIX, fig. 9 842 CAMBRIAN BRACHIOPODA. LinguieUa (Lingulepis) exigua, described ^ 551 compared ^\^th LingulcUa tumida 537 LinguMla (Lingulepis) grcgwa 554, 555 LinguieUa {Lingulepis) longinervis 556 LinguieUa {Lingulepis) jiumila. : 556 LinguieUa {Lingulepis) robcrti 558 confused with, LingulcUa (Lingulepis) grcgwa 554,555 LinguieUa {Lingulepis) grcgwa 537 general geographic and stratigraphic distribution tab- u lated 103 type specimen not figured. young shells more elongate than adult shells 473 gregwa described 554 compared with LinguieUa atava 4S0 LinguieUa cania 4S5 LinguieUa issc 509 LinguieUa radula 529 LinguieUa triparilis 536 LinguieUa {Lingulepis) exigua 552, 553,554 LinguieUa {Lingulepis) longinervis 555 LinguieUa {Lingulepis) pumila 556 LinguieUa {Lingulepis) roberti 558 general geographic and stratigraphic distribution tabulated 103 type specimen not figured. species confused with 479, 4S0, 537, 554, 555 young shells more elongate than adult shells 473 gregwa robusta, described 555 general geographic and stratigraphic distribution tabu- lated 103 type specimen not figured. longinervis, described 555 compared with LinguieUa triparilis 536 LinguieUa {Lingulepis) pumila 556 LinguieUa {Lingulepis) roberti 558 Obolus parvus 408 general geographic and stratigraphic distribution tabu- lated 103 type specimen not figured. pumila, described : 556 general geographic and stratigraphic distribution tabulated 103 type specimen figured PI. XLV, fig. 3 pygmsea, described 556 general geographic and stratigraphic distribution tabulated 103 type specimen figured PI. XXX, fig. 10 roberti, described 557 compared with LinguieUa grandis 502 LinguieUa Irene 509 LinguieUa martinensis 51S general geographic and stratigraphic distribution tabulated 103 type specimen figured PI. XXXVII, fig. 4a Towei, described 558 general geographic and stratigraphic distribution tabulated 103 type specimen figured PI. XXI, fig. 4 spatula, described 558 general geographic and stratigraphic distribution tabulated 103 type specimen figured PI. XIX, fig. 5 squamosa, described 559 general geographic and stratigraphic distribution tabulated 103 type specimen not figured. starri, described 559 compared with LiTigulella minor 519 LinguieUa {Lingulepis) exigua 553,554 general geographic and stratigraphic distribution tabulated 103 type specimen not figured. type specimens lost 559 sp. undt., described 560 general geographic and stratigraphic distribution tabulated 103 type specimen not figured. "Lingulepis dakotensis," compared with LinguieUa cuneola 488 ^' lusitanica," typeof Delgadella 560 "maiinalis," name proposed by Hall 401 '' Lingulepis"— ConVmned. "mceki," specific reference discussed 550 '^minima," mentioned 548 ''pinnaformis," compared with LinguieUa cuneola 488 mentioned 401 synonymy of forms referred to 545-546 '^starri var.," discussed 554 (Lingulepis), see LinguieUa (Lingulepis). '^ Lingulobolus affinis cuncata,'^ discussed 432 (Lingulobolus), sec Obolus {Lingulobolus). Linguloids, shell stnicture of 297 Lingulops, mentioned 297 platform mentioned 309 Linnarsson, J. G. O., bibliographic references 19 genus named for 666 species named for 516, 782 Linnarssonella , described 665 cardinal area discussed 305 classification of 321 , 324 compared with Dicellomus 572 OboleUa 314 ObolcUa aUantica 314 Obnlus 312 evolution discussed 319 evolution of ■ 317 general geographic and stratigraphic distribution of the species referred to 105 general stratigraphic distribution and number of Cam- brian species and varieties of Ill muscle scars discussed 312 number of Ordovician species and varieties of 113 number of species of, in different types of sediment ... 160 pedicle tube discussed ^ 314 reference to, of Linnarssonella tennesseensis discussed. 670 type species Linnarssonella girtyi 665 vascular markings discussed 311 "broadheadi ," discussed 666 girtyi, described 666 cardinal area discussed 305 compared with Linnarssonella modesta 669 Linnarssonella tennesseensis 670 Linnarssonella transversa 670 Linnarssonella urania 671 general geographic and stratigraphic distribution tabu- lated 105 occurrence discussed • 665 type of Linnarssonella 665 type specimen figured Pi. LXXIX, fig. 1 minuta, described 667 compared with Linnarssonella girtyi 667 Linnarssonella modesta 669 Linnarssonella nitens 669 general geographic and stratigraphic distribution tabu- lated 105 occurrence mentioned 666 type specimen not figured. modesta, described 668 cardinal area discussed 305 compared with Linnarssonella nitens 669 Linnarssonella transversa 670 Linnarssonella urania 671 general geographic and stratigraphic distribution tabu- lated 105 occurrence mentioned 666 type specimen figured PI. LXXVIII, fig. 8e nitens, described ' 669 compared with Linnarssonella modesta 669 general geographic and stratigraphic distribution tabu- lated 105 occurrence mentioned 666 type specimen figured PI. LXXVIII, fig. 7 tennesseensis, described 669 compared with Linnarssonella modesta 669 general geographic and stratigraphic distribution tabu- lated 105 occurrence mentioned 666 type specimen figured PI. LXXIX, fig. 3 transversa, described 670 compared ^vith Linrmrssonella modesta 669 Linnarssonella nitens 699 INDEX. 843 Linvarssonella transversa — Continued. general geographic and stratigraphic distribution tab- ulated 105 occurrence mentioned 666 type specimen figured PL LXXVIII, flg. 6 Urania, described 670 general geographic and stratigraphic distribution tabu- lated 105 occurrence mentioned 666 type specimen figured PI. LXXVIII, fig. 9a iinnarssoni, see Eoortkis and LinguUlla. "Linnarssonia," compared with Acrotreta 673 discussed 666, 673 mentioned 650, 691, 705 "telti magna," compared with Acrotreta gratia 687 "cf. preiiosa," discussed 705 Xiostracus linnarssoni, association mentioned 531 steimrmnni, association mentioned 499 ulTichi, association mentioned 499 sp., association mentioned 499 I/i San, species named for , 693 lisani, see Acrotreta. Listrium, defined 294 discussed 306 Xittle Antietam Creek, Maryland, locality on 16f liittle Belle Island, Newfoundland, localities on 114, 114a stratigraphic position of beds on, discussed 4f;2 lylttle Belt Mountains, Montana, locality in 340f Xittle Belt Mountains quadrangle, Montana, localities in . 4x, 5f , 5k, 340 Xiittle Bras d'Or Lake, Cape Breton, localities near 3o, 3q, 10 1 Xittle Conestoga Creek, Pennsylvania, locality on 12v Xittle Metis, Quebec, locality at 392g stratigraphic position of beds at, discussed 705 Xittle Rocky Mountains, Montana, locality in 302z Xiver, sho-\vn in figure 374 Liverpool road, near York, Pennsylvania, locality on 49a Xivingston quadrangle, Montana, localities in 4r, 148a, 302f Xlanberis, North Wales, locality in 366e Xlandeilo shales (Lower Ordovician), in generalized section for England, Scotland, and Wales, listing species and localities 135 localities in 316, 316a XIano County, Texas, localities in 14b, 14c, 14r, 68, 68e, 68y, 68z, 353c Xlanvim, in generalized section for England, Scotland, and Wales. 135 Xlyn Dywarchen, North Wales, locaUty at 3661 Xocalities, authority for citation explained 328 explanatory statements 160-161 italics in explained 328 Xocalities 1-227 : 161-229 Xocalities 300-396z 229-286 Xocalities C1-C75 286-291 Xoch Maree, Scotland, localities near 316c, 316d Xodenitz, Bohemia, locality at ; 303o Xodi, Wisconsin, localities at 86, 328i, 328 1 Xogan, Montana, localities near 4g, 4h, 41i, 4p, 302t Xogan, Sir William E., species named for 351 Jogani, see Micromitra (Paierina). Lone Mountain, Nevada, locality on 221 Xong Island, Kennebecasis Bay, New Brunswick, localities on . . . 2u, 2x, 308g Xong Reach, St. John River, New Brunswick, localities on 2y 300, 301f, 308d Xong Point, Trinity Bay, Newfoundland, locaUty near 6w Jonginervis, see LinguleUa. (Lingulepis). Xongitudinal axis, defined 294 Lookout Mormtain, Eureka district, Nevada, locality on 56 Lookout Pass, Onaqui Range, Utah, locality near 33f Xoper, S. Ward, acknowledgments 13 species named for 396 subgenus named for 744 2operi, see Obolus. iZoperia), see ProtortUs (Loperia). L'Original, on the St. Lawience River, Canada, locality near 319o Xos Negros, Spain, locaUty at 350b Louga (Luga) River, St. Petersburg, Russia, localities on . . . 336u, 395z Xouise, see Lake Louise. Mmise, see Micromitra (Iphidella). Lovened, Sweden, localities at 310q, 320h, 320n Low, A. P., species named for 734 Low Hampton, New York, localities near 34, 39, 45b ■"Lower black slates" (Upper Cambrian), locality in 318m Lower Cambrian: Alabama, generalized section listing included and correlated species and localities 147 Alberta, species and localities correlated with those of British Columbia 129-131 Bohemia, localities and species in listed 124 British Columbia, detailed section listing species and locali- ties 129-131 CaUfornia, species and localities correlated with those of Nevada 137-138 Cape Breton, note on its absence 135 Denmark, generalized section listing included and correlated species and localities 146 England, generalized section, listing species and localities. . 136 families represented in, listed H2 Finland, generalized section, listing included and correlated species and localities 145 genera identified in, listed 110-111,317 Georgia, generalized section, listing included and correlated species and localities 147 line of separation between Middle Cambrian and, in Cor- dilleran region 148,153 Nevada, detailed sections, listing included and correlated species and localities 137-138,140 New Brunswick, note on 135 Newfoundland, detailed section, listing species and localities. 141 Norway, generalized section, Usting included and correlated species and localities 146 Russia, generalized section, listing species and localities 144 Scotland, generalized section, Usting species and localities. . , 136 species from, discussed 316, 318 species from, listed 89-109 Sweden, generalized section, listing included and correlated species and locahties 146 Tennessee, generalized section, listing included and corre- lated species and locahties 147 Utah, detailed section, listing included and correlated species and locahties 153 Wales, generalized section, listing species and localities 136 " Lower graptolite slate" (Passage beds), locality in 390f "Lower lenticular layer" ("Linsenschicht") (Passage beds), in generalized section for Russia 143 localities in or near 396m, 396p Lower Stockingford shales, in generaUzed section for England, Scotland, and Wales, listing species and localities 135 lowi, see Nisiisia (Jamesella). Lucinia divaricator, surface ornamentation discussed 301 Luga River, see Louga River. Lugnis, Sweden, localities at 309d, 390j Luh, near Skrej, Bohemia, locality at 345e Lumpam, Aland Island, Finland, locality near 311e Lumparstrommen, Aland Island, Finland, locality near 311d Lund, Sweden, localities near 309, 309a, 309h, 309i, 310t, 320d, 321s, 321t, 321z, 390b, 390g lusitanica, see Delgadella. Lyck, East Prussia, locality near 386c lyncioides, see Orusia lenticularis. Mc-\dam shore. East Bay, Cape Breton, localities on lOr, 325, 372d McAphee's corner, Hardingville, New Brunswick, locaUty at 301s McCodrum Brook, Cape Breton, localities on and near 3i, 344n mcconnelli, see Obolus. mcconnelli decipien^, see Obolus. mcconnelli pelias, see Obolus. McCoy, F., bibliographic references ■. 19, 20 McGill post office, Nevada, locality near 313 McGill's ranch, Nevada, locaUty near 8p McGregor, Iowa, locality at 341a Mackenzie Basin, British Columbia, locality in 306 McKinley Canyon, CabaUos Mountains, New Mexico, locality in. . 327a McLean Brook, Cape Breton, locaUties on 3i, 10s, lOt, 307f, 307g McLeod Brook, see Barachois River. McMinn County, Tennessee, locality in 128a McMullins Brook, Cape Breton, locaUties on I60, 372e MoMulliu's place. Cape Breton, localities near 3p, lOd, 372b McNaughton Corner, New York, locaUty at 45a McNeil Brook, Cape Breton, locaUties on and near 3h, 3071, 325a MePhees, Cape Breton, locaUty at 344j McPhees Brook, Cape Breton, localities on and near lOp", 307b McPhees Point, see Youngs (McPhees) Point. macra, see Nisusia {Jamesella) perpasta. 844 CAJMBRIAN BRACHIOPODA. maculata, see Acrothele, Madison, Wisconsin, locality near 85z Madison County, Missouri, localities in llj, 369f, 369h Madison County, Montana, locality in 149a Madison Mountain, Montana, locality at 302w Maent^Tog, North Wales, localities near 3181, 318m mxra, see Obolus. magna, see AcTotreta sagittalis. Maiden Arm, Hare Bay, Newfoundland, locality at 314g major, see BilUngsella, MicromitTa (Paterina), and Rustella. Malad City, see Malade. Malade, Idaho, localities near 4y, 5a-c, 5h, 54s-x, 55d maladen^is, see Micromitra (Iphidella) pannula. Mallada, L., bibliographic reference 20 Malmohus, Sweden, localities in.., 309, 309a, 309b, 309e, 309h, 309i, 310h, 310t-z, 320d, 320j, 320k, 321s, 321t, 321z, 323j, 323k, 390b, 390g Malvern Hills, England, localities in 304, 304a-g Malvem "quartzite" (Lower Cambrian), in generalized section for England, Scotland, and Wales, listing species and locali- ties 136 localities in 304c, 304d Main vascular canals, shown in figure 374 Mammoth, Utah, locahties near 34n, 34s Mammoth limestone (Middle Cambrian), locaUtiesin 34n?, 34s Manitou, Colorado, localities near 186, 186a. 187, 360a, 360f, 360g manitouensis, see Schizamhon. manticula, see Lingulella. Manto shale (Lower Cambrian), localities in C3, 017, C20 Manuels, Conception Bay, Newfoundland, localities near 5p, 5r Manuels Brook, Cx)nception Bay, Newfoundland, localities on 1, la, 2, 3, 6 1, en, 6r, 6u, 6v, 41, 314h Manuels Brook section, in detail, listing species and localities 140-141 sjrecies associated with LiJigulella ferruginea in 498 Manuels Brook section, 6 (Middle Cambrian), localities in la, 6 1, 6n Manuels Brook section, 7 (Middle Cambrian), locaUtiesin 1, 2 Marble River, New York, locality on Ill Marchillyn-mawr, North Wales, locality at 366e Maree, see Loch Maree. Mariehamn, Aland Island, Finland, localities in.. 311f, 311q, 311w, 311y Marienwerder, West Prussia, locality near 386 1 Mariestad, Sweden, localities near 309d, 390j marion, see BilliTigsella. Marion Bridge, Cape Breton, locahties at and near 3h, 3i, 3ii, 10s, lot, llz, 307g Marjum limestone (Middle Cambrian), in detailed section in House Range, Utah, listing included and correlated species and localities 155-156 locaUtiesin 3w-y, 81, lOy, lOz, lln-q, llx, lly, 15c, 30g, 30z Marjum Pass, House Range, Utah, localities near 3w, lOy, lOz, lln, lip, 30h, 30j-n, 30n', 30o, 30w, 30z, 31t marjumensis, see Acrotreta. Marthas Vineyard, Massachusetts, locaHty on 326 martinensis, see Lmgulella. Mary Dingle, England, locaUties at 304h, 304i Maryland, Cambrian species of, listed 114-119 localities in 16f , 47d-f note on stratigraphic position of localities in 159 Maryville limestone (Middle Cambrian), in generalized section for Termessee, Georgia, and Alabama, listing species and lo- calities 147 locality in 123 Massachusetts, Cambrian species of, listed 114-119 first notice of fossiliferous Ordovician pebbles ui 464 locaUtiesin 5, 9n, 326, 326a-g matlhewi, See AcTothele. matthewi eryx, see Acrothele. matthewi lata, see Acrothele. matthewi multicostata, see Acrothele. Mathews, E. B., [Clark, W. B., and], bibliographic reference 15 matinalis, see Obolus. Matley, C. A., bibliographic reference 20 Matthew, George F., acknowledgments 12 bibliographic references 20, 21 species named for 649 Maxfield Mine, Big Cottonwood Canyon, Utah, locaUties near. . 33i, 55u maximus, see Obolus apoUinis. Maynardville quadrangle, Tennessee, locality in 11a Mazomanie, Wisconsin, locaUties near 85x, S85x, 328p Mazouka Canyon, California, locaUty in 176a Meagher County, Montana, locaUties in 5f, 5k, 9h, 340 Meall i, Gliiubhais near Loch Maree, Scotland , localities on 316c, 316d Meath, Ireland, locaity in 317a Mecklenburg-Schwerin, Germany, locaUties in 386e-g Median ridge, shown in figure 374 Median septum, defined 294 shown in figure 374 Meek, F. B., bibliographic references 21 species named for 550 Meek, F. B., and Hayden, F. V., bibliographic references 21 meeki, see Lingulclla (Lingulcpis) acuminata. " Meekina prima," discussed 669 Megalaspis planilimbata zone, in generalized section for Russia 145 See also Planilimbata limestone. Melinda Ferry, Tennessee, locaUties near 9a, 101, 101a, 101b, 102 membranaceus, see Obolus. mencghinii, see Obolus. Menevian group, in generalized section for England, Scotland, and Wales, listing species and localities 13& mentioned 723 species associated with Lingulella ferruginea in 498 Menevian (Middle Cambrian) , localities in . 318d-f , 318h, 318J-1, 318p, 318r Menomonie, Wisconsin, localities at and near,. 79a, 80, 82a, 100, 134, 134a Mercersburg, Pennsylvania, locaUty near 346b Merionethshire, North Wales, locaUtiesin... 305f, 318, 366a, 366f-q, 366s Meseritz, Germany, locality near 386h. Mesonacis torelli zone (Lower Cambrian), in generalized section for Sweden, Denmark, Finland, and Norway, listing species and locaUties 14& mentioned 596 locality in 321t Jl/fi/a(fox/des, association mentioned 584 Metis, Quebec, locality at 319h stratigraphic position of beds at discussed 705 See also Little Metis. Mettawee quadrangle, New York, localities in 22a, 38c, 338v" Mettawee River, New York, localities on 20, 21a Meyer's mill, near Emigsville, Pennsylvania, locality at 49 Michigan, Cambrian species of, listed 114-119 localities in ; 330, 330a, 330b note on stratigraphic position of localities in 159 Mickwitz, A . , acknowledgments 11 bibliographic references 21 genus named for 329 mentioned 367 minute discriminations by, discussed 378 species and varieties of Obolus and subgenera recognized by, in R ussia, listed 380 species named for 404 subgenus named for .'. 434 ( Mickwitzdla),seQ Obolus ( Mickwitzella). mickwitzi,se& Obolus. Mickwitzia, described 329 cardinal area discussed 303 classification of 321, 322 compared with Helmersenia 368 Micromitra 329, 330, 331 Schizocrania 331 evolution discussed 318 evolution of 317 false cardinal area mentioned 318 general geographic and stratigraphic distribution of the species referred to 98 general stratigraphic distribution and number of Cam- brian species and varieties of 110^ muscle scars not shown in 312 number of species of, in different types of sediment 160 surface ornamentation discussed 301, 302 type species "Xra^w?a ? monilifera" 329 formosa, described 329 compared with Mickwitzia monilifera 329, 330, 331 general geographic and stratigraphic distribution tabulated 98 type specimen figured PI. VI, figs. 3, 3a-c mom7//cra. described 330- cardinal area discussed 303 compared with HclmcTsenia ladogeTisis 368 Eutorgina perugata 584 Mickwitzia formosa 329,, 330, 331 Mickwitaia pretioza 332 Mickwitzia sp. undt 332 INDEX. 845 Mickwitzia monilifera—Contiimed. general geographic and stratigraphic distribution tabulated 98 type specimen not figured. occidens, described 331 compared with Mickwitzia pretiosa 331-332 general geographic and stratigraphic distribution tabulated 98 type specimen figured PI. VI, fig. 4 pretiosa, described 332 compared with Mickwitzia monilifera 332 Mickwitzia occidens 331-332 general geographic and stratigraphic distribution tabulated 98 type specimen figured PI. VI, fig. 2 sp. undt. , described 332 compared with Lingula rouauUi 332 Mickwitzia moniUfera 332 general geographic and stratigraphic distribution tabulated 98 type specimen not figured, Mickwitzia conglomerate (Lower Cambrian), in generalized section for Russia, listing species and localities 144 in generalized section for Sweden, Denmark, Finland, and Norway, listing species and localities 146 locality in 396q Microdiscus connexus, association mentioned 707 Microdiscus punctatus, association mentioned 498, 707 MicTomitra, described 332 apical depression, slit, or foramen in species of, dis- cussed 334,335,366 cardinal area discussed 303 , 304 classification of 321,322 compared with Acrothcle 631,632 ^. Acrothcle woodworthi 661 AcTotreta f cancellata 679 Curiicia 318 Kulorgina '. 580, 582 Linnarssonella 665 Mickwitzia 329, 330, 331 Schizambon f esthonia 622 Volborthia 366 delthyrium discussed 318 evolution discussed 318 evolution of 317 general geographic and stratigraphic distribution of the species referred to '. 99 general stratigraphic distribution and number of Cam- brian species and varieties of 110 interior of, unknown 333 mentioned 316, 344, 349, 357, 359, 361 , 674 muscle scars not showni in 312 notes on use as a generic name 334, 341 number of species of, in different types of sedi- ment IGO shell substance 297 species referred to, listed 33C stratigraphic distribution 336 surface ornamentation discussed 301 systematic position discussed 335 type of ornamentation characteristic of 333, 335, 336 type species Micromitra sculptilis 333, 335, 336 alahamacnsis, described 337 compared with Micromitra (PateriTia) labradorica utahensis 349 general geographic and stratigraphic distribution tabulated 99 type specimen figured PI. II, fig. 5 haydeni, described 337 compared with Micromitra sculptilis 341 general geographic and stratigraphic distribution tabulated 99 habitat mentioned 159 type specimen figured text fig, 20A, 338 nisus, described 338 general geographic and stratigraphic distribution tabulated 99 type specimen figured PI. II, fig. 10 pealei, described 339 apical sht in discussed 335 Micromitra pealei — Continued. compared with Linnarssonella girtyi 666 Micromitra nisus 338 Micromitra (Iphidclla) louise 359 Micromitra iPaterina) crenisiria 335 Micromitra (Paterina) siuarti 356 delthjTium discussed 318 general geographic and stratigraphic distribution tabulated 99 surface ornamentation discussed : 301 type specimen figured PI. Ill, figs. 3, 3ar-b pusilla, described 339 association mentioned 340 compared with Micromitra scotica 340 general geographic and stratigraphic distribution tab- ulated 99 type specimen not figured. scotica, described 340 association mentioned. 340 general geographic and stratigraphic distribution tab- ulated 99 type specimen figured text fig. 21A, 340 sculptilis, described 341 compared with Micromitra alabamaensis 337 Micromitra sculptilis endlichi 342 Micromitra haydeni 338 Micromitra nisus 338 Micromitra pealei 339 Micromitra zenobia 342 Microm itra sp. undt 343 Micromitra {Iphidclla) pannula 362, 363 Micromitra (Paterina) labradorica 335 Micromitra (Paterina) slissingensis 353, 354 general geographic and stratigraphic distribution tab- ulated 99 labeling of type specimen described 334 stratigraphic distribution 336 surface ornamentation characterized 333, 335, 336 surface ornamentation discussed 301 type species of Micromitra 335, 336 tj^e specimen figured PI. in, fig. 5 sculptilis endlichi, described 342 general geographic and stratigraphic distribution tabu- lated 99 t5T)e specimen figured text fig. 22, 342 zenobia, described 342 compared %vith Micromitra (Paterina) stissingen^is 354 Micromitra (Paterina) slissingensis ora 354 general geographic and stratigraphic distribution tabu- lated 99 type specimen figured text fig. 23, 342 sp. undt., described 343 general geographic and stratigraphic distribution tabu- lated 99 tj'pe specimen figured PI. Ill, fig. 7 Micromitra {Iphidclla), described 359 apical depression, sht, or foramen in species of dis- cussed 334, 335 classification of 321, 322 compared with Obolus and RMnobolus 335 evolution of 317 general geographic and stratigraphic distribution of the species referred to 99 general stratigraphic distribution and number of Cambrian species and varieties of 110 interior of, described so far -as known 333 number of species of, in different types of sediment- . . 160 species referred to, listed 336 stratigraphic distribution of 336, 337 surface ornamentation discussed 301 systematic position discussed 335 type of ornamentation characteristic of 333, 336 type species " Trematis pannulus" 359 louise, described 359 general geograpliic and stratigraphic distribution tabulated 99 stratigraphic position discussed 359 stratigraphic position mentioned 316 surface ornamentation discussed 301 type specimen figured text fig. 31A, 359 846 CAIIBEIAN BRACHIOPODA. MicTOfnitra {Iphidella) nyssa, described 360 compared \\'ith Micromitra (Iphidclla) louise 359 general geographic and stratigraphic distribution tabulated 99 strat igraphic position mentioned 359 sm'face ornamentation discussed 301 type specimen figured PI. Ill, fig. 9 ornatcUa, described 3G0 apical foramen in, discussed 334, 335 apical opening in embryonic stages discussed 335 area in dorsal valve mentioned 334 association mentioned 340 compared with Micromitra (Iphidclla) nyssa 360 Micromitra (Iphidella) pannula 335, 362 Micromitra (Paterina) bella 334 Micromitra (Paterina) Jabradorica swantoneiisis. 334 Micromitra (Paterina) wapta 357 general geographic and stratigraphic distribution tab- ulated 99 interior of, described so far known 333 surface ornamentation representative 336 type specimen not figured. pannula, described 361 apical depression in 335 area of dorsal valve described 334, 335 cardinal area discussed 303 compared with A crotkele bellapunctata 633, 637 Botsfordia pulchra 602 Discinolepis granulala 664 Kutorgina perugata 584 Micromitra alabamaensis 337 Micromitra (Iphidclla) nyssa 360 Micromitra (Iphidella) ornatella 335,361 Micromitra (Iphidella) pannula ophirensis 365 Micromitra (Paterina) bella 334 Micromitra (Paterina) labradorica swantonefisis , 334 delthyrium discussed 318 general geographic and stratigraphic distribution tab- ulated 99 habitat and distribution nientioned 159 stratigraphic position mentioned 316. 336, 355, 356 surface ornamentation characterized 333, 336, 341 surface ornamentation discussed 301 , 302, 336 type specimen figured PI. IV^ figs. Ig and 16 varieties of, characterized 363, 364, 365 pannula maladensis, described 364 characterized , , 363 compared with Micromitra (Iphidella) louise 359 Micromitra (Iphidella) pannula 363 general geographic and stratigraphic distribution tab- ulated 99 type specimen figured PI, IV, fig. 2e pannula ophirensis, described 365 characterized 363 general geographic and stratigraphic distribution tab- ulated 99 interior of, described so far as known 333 stratigraphic distribution 330, 337 type specimen figured PL IV, fig. 4a Micromitra (Paterina), described 343 apical depression, slit, or foramen in species of, dis- cussed 334, 335 classification of 321, 322 evolution of 317 general geographic and stratigraphic distribution of the species referred to 98 general stratigraphic distribution and number of Cam- brian species and varieties of no interior of, described so far as known 333 number of species of, in different types of sediment- . . 160 species referred to, listed 336 surface ornamentation discussed 301 systematic iwsition discussed 335 type of ornamentation characteristic of 333,336 type species discussed 336. 344 type species Micromitra (Paterina) labradorica swan- tonensis 344 mentioned 352 Micromitra (Paterina) bella, described 344 apical foramen in, discussed 334, 335, 345 area in dorsal valve not seen , 334 cardinal area discussed 303 compared with Micromitra pealei 339 Micromitra sculptilis 341 Micromitra (Iphidella) ornatella 334 Micromitra (Iphidella) pannula 334,363 Micromitra (Paterina) crenistria 345 Micromitra (Pateriria) labradorica 334 Micromitra {Paterina ) superba 335,356 general geographic and stratigraphic distribution tab- ulated 99 not the type of Micromitra (Paterina) 336 surface ornamentation representative 336 type specimen discussed 335. 345, 350 type specimen figured Pi. II, fig. ic type specimen (7) referred to Micromitra (Paterifia) logani 335,345,350 crenistria, described 345 compared \vith Micromitra pealei 335 Micromitra (Paterina) logani .. .^ 345, 350 Micromitra (Paterina) stuarti 355 general geographic and stratigraphic distrilDution tab- ulated 99 type specimen figured PI. Ill, figs. A, 4a^b etheridgei, described 346 general geographic and stratigraphic distribution tab- ulated 99 type specimen figured Pi. Ill, fig. lo labradorica, described 347 area in dorsal valve mentioned 334 association mentioned 328 compared with Kutorgina 333 Micromitra alabamaenms 337 Micromitra pealei 339 Micromitra pusilla 340 Micromitra sculptilis 335 Micromitra (Iphidella) nyssa 360 Micromitra ( PateriTia) bella 334 Micromitra (Paterina) crenistria 345 Micromitra (Paterina) labradorica swantonensis. 349 Micromitra ( Paterina ) labradorica utahensis 349 ^Mcrom^tra (Paterina) labradorica var. undt... 350 Micromitra (Paterina) major 351 Micromitra ( Paterina) philHpsi 352 Micromitra (Paterina) stissingensis 353 Micromitra ( Paterina ) superba 356 Micromitra ( Paterina ) undosa 357 Micromitra (Paterina) wapta 357 general geographic and stratigraphic distribution tab- ulated 99 interior of, described so far as known 333 notes on generic reference of 334 stratigraphic position mentioned 316. S18 surface ornamentation characterized 333,336 type specimen figured PI. II, fig. 2 labradorica orientalis, described 348 compared with Obolus obscurus 407 general geographic and stratigraphic distribution tab- ulated 99 type specimen ligured PI. II, fig. 11 labradorica swantonensis, described 348 compared with Micromitra alabamaensis 337 Micromitra (Iphidclla) ornatella 334 Micromitra (Iphidella) pannula 334 Micromitra (Paterina ) labradorica 347 Micromitra (Paterina) labradorica orientalis 348 Micromitra (Paterina) labradorica utahensis 349 Micromitra (Paterina) prospectensis 353 general geographic and stratigraphic distribution tabulated 99 surface ornamentation representative 336 type of Beecher's genus "Paterina" 334,344,349 type species of Micromitra (Paterina) 344 type specimen figured PI. 11, fig. 3 labradorica utahensis, described 349 compared with Micromitra (Paterina) stuarti 355 INDEX. 847 Micromitra {Patcrirm) labradorica utahemis— Continued. general geographic and stratigrapliic distribution tabulated 99 type specimen figured PI. II, fig. S labradorica var. undt., described 350 general geograpbic and stratigraphic distribution tabulated 99 losdni, described 350 cardinal area discussed 303 compared with Micromitra (Paierina) crenistTia 345,350 Micromitra {Patcrina) stuarti 355 founded on type specimen (?) of Micromitra {Paterina) bella 350 general geographic and stratigraphic distribution tab- ulated 99 the type (?) of Micromitra {Paterina) bcUa 335, 345, 350 type specimen figured Fl. II, figs. 6, 6a-b major, described 351 confused with Obolus smithi 351 general geographic and stratigraphic distribution tab- ulated 99 'original description included specimens now referred to Micromitra (Paterina) wiUiardi 351 type specimen figured test fig. 25, 351 phillipsi, described « 351 confused with Kutorgina cingulata 352 general geographic and stratigraphic distribution tab- ulated 99 type specimen figured PI- HI, fig. S prospcctcnsts, described 352 compared with Micromitra (Paterina) wapta 357 general geographic and stratigraphic distribution tab- ulated 99 type specimen figured PI. II, fig. 4 - stissingensis, described 353 compared with Micromitra alabamaensis 337 Micromitra (Iphidclla) pannula 362 Micromitra (Paterina) stissingerisis ora 354 Micromitra {Paterina) wapta 357 general geographic and stratigraphic distribution tab- ulated 99 type specimen figured '. PI. Ill, fig. 1 stissingeJisis ora, described 354 general geographic and stratigraphic distribution tab- ulated 99 type specimen not figured. stuarti, described 354 general geographic and stratigraphic distribution tab- ulated 99 stratigraphic position mentioned 355, 356 type specimen figured text fig. 26A, 355 superha, described ». 355 apical slit absent 335 cardinal area discussed 303 compared with Micromitra pealci 339 Micromitra (Paterina) bella 335 Micromitra (Paterina) crcnistria :. . . 345 Micromitra (Paterina) etheridgci 346 Micromitra (Paterina) labradorica utdhensis 349 Micromitra ( Paterina) tvilUardi 358 general geographic and stratigraphic distribution tabu- lated 99 pseudodeltidium in ventral valve described 334 stratigraphic position mentioned 355, 356 type specimen figured PI. II, figs. 7, 7a-b undosa, described - 356 general geographic and stratigraphic distribution tabu- lated 99 type specimen figured text fig. 2SB, 356 wapta, described 357 confused with. A crothcle colleni 357 general geographic and stratigraphic distribution tabu- lated 99 type specimen figured text fig. 29A, 357 williardi, described 358 confused with Micromitra (Paterina) major 351 general geographic and stratigraphic distribution tabu- lated 99 type specimen figured text fig. 30A, 358 Microscopic shell structure 297-300 microscopica, see Acrotreta. microscopica missouriensis, see Acrotreta. microscopica tctonensis, see Acrotreta. Middle Cambrian, Alabama, generalized section, listing included and correlated species and locahties 147 Alberta, species and localities correlated with those of British Columbia 126-129 Bohemia, generalized section, listing species and localities. . 124 British Columbia, detailed section, listing species and localities 126-129 Cape ■ Breton, generahzed section, listing species and localities 131-135 Denmark, generahzed section, listing included and cor- related species and localities 145-146 England, generalized section, listing species and localities. . 136 families listed 112 Finland, generahzed section, listing included and correlated species and localities 145-146 genera listed 110-111, 317 Georgia, generalized section, listing included and correlated species and localities 147 line of separation between Lower Cambrian and, in Cor- dilleran region 148,153 Missouri, generalized section, listing species and localities.. 137 Nevada, detailed section, listing species and localities... 139-140 New Brunswick, species and localities in, correlated with those of Cape Breton 131-135 Newfoundland, detailed section, listing species and locahties 140-141 Norway, generalized section, Hsting included and cor- related species and localities 145-146 Scotland, generahzed section, listing species and localities. . 136 species hsted 98-109 Sweden, generalized section, listing included and correlated species and localities 145-146 Tennessee, generalized section, listing included and corre- lated species and locahties 147 Utah, detailed section, listing included and correlated spe- cies and localities 149-153, 154^1^ Wales, generalized section, listing species and localities — 136 Middle Granville, New York, localities at and near 22a, 38c, 338v Middle lateral muscle scar, defined 294 shown ia figure 374 Middle Lingula flags, in generalized section for England, Scot- land, and Wales, fisting species and locahties 135 Middle Mountains, see Mittelgebirge. Middle Popo Agie Canyon, Wyoming, locality in 302e Midsummer Hill, Malvern Hills, England, locaUty on 304d Milinsky Wrch, near Woleschna, Bohemia, locality at 303h Milk Ranch, Clifion quadrangle, Arizona, locaUty near 9o Millard County, Utah, localities in 3s, 3t, 3w-y, 4, 8g, 8i, 8k, lOy, lOz, lln-q, llu, llw-y, 14v, 15b, 15c, 30d, 30e, 30g, 30h, 30j-n, 30n', 30o, 30w. 30y, 30z, 31q, 31s, 31t, 31v, 33 1, 33n, 33r, 105t Mill Canyon, near Liberty, Idaho, locahties in and near 55c, 56f, 56g, 59f, 59g, 163 Mill Creek, near Landusky , Montana, locality on 302z Miller, S. A., bibhographic reference 21 Mine Lamotte, Missouri, localities at •. Jlj,369h Mineral Hill, Eureka district, Nevada, locality on 57b minima, see Acrotreta. minimus, see Obolus and Obolus lamborni. Miniska, see Minneiska. Minneiska (Miniska), Minnesota, localities near 99, 339f Minneiska (Miniska) River, Minnesota, locality near 339h Minnesota, Cambrian species of, listed 114-119 localities in 82b, 82c, 84, 84a, 84f, 84s, 97, 97b, 97s, 97x, S97s, 98a, 99, 113, 131, 339, 339a-k, 364, 364a note on stratigraphic position of localil.ies in 159 minor, see Acrotkyra, Lingulella, OboleUa, and Obolus. minuta, see Acrothcle and Linnarssonella. Miosen, see Lake Miosen. Miquel, J. , bibliographic references , 21 species named for 612 miqucli, see YorUa. Mira River Valley, Cape Breton, localities in 2c, 307c, 307f, 307g:, 3071, 325a, 344ii 848 CAIVIBRIAN BRACHIOPODA. mirandus, see Obolus. miscra. see Acrotnta. Mississippi River, localities on 99, 328g, 339e, 339f , 3391 See also Wisconsiu and Minnesota. Mississippi Valley, only one species of Acrotrcta in upper part 711 Missisquoi Bay, Quebec, locality on 392m Missouri, Cambrian species of, listed 114-119 generalized section of Cambrian in, listing species and localities 137 localities in lid, lie, llj-m, 369, 369a-h missouriensis, see Acrotreta microscopica. Mittelgebirge, Poland , locality in .• 368a Mjosen . see Lake Mjosen . Mleschitz, Bohemia, locality at 345c Moberg, Job. Chr. , acknowledgments 12 bibliographic references 21 species named for 598 Moberg, J. C.,andSegerberg,C. O., bibliographic reference 21 mohergi, see Obolella. Mobergia, discussed 602,607 modesta, see Linnarssonella. Moel-y-gest, North Wales, locality at 305a Moffat . Scotland , locality near 316 MoUer, V. von, bibliographic reference 21 Mona, Utah, locality near 14t ■moniUfera, see Mickwitzia. MonoboUna , compared with Obolus and Elkania 378, 410 MonoboUna plumbea, discussed 410 Monomerella, Hall and Clarke on development of 309 platform mentioned 309 Montagne Noire, France, locality in 342 Montana, Cambrian species of, listed 114-119 locaUties in (Lower Cambrian) 4v, 4w, 5j locaUties in (Middle Cambrian) 3j, 4g, 4h, 4k, 4p-q, 4u, 4x, 5f, 5k, 8j, 9h, 9k, 9m, 149a, 155a, 156a, 159, 302, 302a, 302b, 3D2k, 302s-t, 302w, 302z, 340, 340a, 340e, 340f locahties in (Ordo^ician) 302j localities in (Upper Cambrian) 4r, 147a, 148a, 150a, 151, 151a, 152, 152a, 152b, 153, 153a, 154, 155, 156b, 157, 158, 158a, 160, 160a, 161, 302f, 302n, 302q-r, 340b stratigraphic position of localities in, discussed 137 Montana, Missouri, localities near lid, 369e montanensis, see Clarkella. Monte de Valbom, Alemtejo, Portugal, locality at 351 Montevallo, Alabama, localities near 141a, 142, 164f "Montevallo shale" (Lower Cambrian), in generalized section for Tennessee, Georgia, and Alabama, listing species and lo- calities 147 localities in 17b, 56c Montpelier, Idaho, localities west of 55c, 56f, 56g, 59f, 59g, 163, 322 Montreal Island , Canada, locality on 319ii Morenci , Arizona, locality near 358 Morgan County, Utah, locahty in 329c Morgans Creek, Texas, localities on 70, 70a, 70e, 353a Morris, J., bibhographic references 21 Morristown quadrangle, Tennessee, localities in, . . 103a, 103b, 104, 374a Moses Hill, near North Greenwich, New York, locality on 43 mosia, see LinguleUa. mosia osceola, see Lingulella. Mossebo, Sweden, locality at 390f Mountain Island, Minnesota, localities on 339e, 339i Moimt Billingen, Sweden, locality on 321p See also Billingen. Moimt Bosworth, Alberta, localities on 35c, 35g, 35h, 57c, 57d, 57e, 57k, 57s, 57y, 58z Moimt Bosworth section, in detail, with included and correlated species and localities 125-131 Mount Delano, Montana, locality near 4r Mount Dennis, British Columbia, locality near 58r Moimt Field, British Colimibia, Burgess shale on, mentioned 127 locality near 35k Mount Helena, Montana, locality on 302s Mount Holly Gap, Pennsylvania, locality at 49f Mount Nebo Canyon, near Mona, Utah, locality in I4t Mount Stephen, British Columbia, localities on I4s, 35f, 57e, 57f, 57j, 57m, 57n, 57r, 58j-l, 58p, 58r, 58s Ogijgopsis zone in discussed 127 Mount Washington, near Eau Claire, Wisconsin, locality on 78a Mount Whyte, Alberta, locality on 35e Mount Whyte formation (Lower Cambrian), detailed section, hst- ing included and correlated species and localities 129-130 localities in ... . 35c, 35e, 35f , 35h, 57e, 57m, 57r, 57s, 58k, 58pl, 58s Mount Zion Church, near York, Pennsylvania, locality near 49e multicostata, see Acrothele matthewL Mimkesten, Sweden, locality at 320e, 321q Murchison, R. I., bibliographic references 22, 23 Murphrees VaUpy, Alabama, locality in 89 Murray, A., bibliographic reference 22 species named for 406 muTraiji, see Obolus. Muscle scars, determination of 460 discussed 312-313 Muskrat Spring, Stansbury Range, Utah, localities near 32f, 32g, 32j, 32k, 32o, 34u, 34v Nahant, Massachusetts, localities at 326c, 326g "Nahant limestone" (Lower Cambrian), locality in 326c Tiamouna, see Obolus. Nankiang River, China, localities on C32, C32 nanno, see LinguleUa. Nant-y-groes, North Wales, locality near 366m nanus, see Dicellomus. Narke, see Nerike. Narragansett B ay , Rhode Island , locality on 343 Narwa, Esthonia, Russia, localities at 336s, 336z locahties west of 337f , 337g, 395d, 395k, 395q, 395t Nathorst, A. G., species named for 521 natkorsti, see LinguleUa. Natrona County, Wyoming, locality in 302o Natural Bridge, Virginia, locality near 47a nautes, see Nisusia (Jamesella). Navy Island, St. John Harbor, New Brunswick, localities on. 308, 308a Neanic, defined 295 Nebo Canyon, see Mount Nebo Canyon. neboensis, see Acrotreta. Neihart, Montana, localities near 4x, 5f, 5k, 340 NeoboUnse, classification of 321, 323 genera and species referred to described .'. 564-567 Neoholus, described 564 cardinal area discussed 304, 305 classification of 310, 321, 323 , 566 evolution discussed 318 evolution of 317 general geographic and stratigraphic distribution of the species referred to 103 general stratigraphic distribution and number of Cam- brian species and varieties of 110 Hall and Clarke on development of 309 number ofspecies of, in different types of sediment 160 platform mentioned 309 warthiy described 566 compared with Obolus apoUinis 564 discussed 566 general geographic and stratigraphic distribution tabu- lated 103 type specimen figured PI, LXXXI, fig. .2f "wynnei," discussed 567 Neobolus beds (Middle Cambrian), localities in 357.357a-c Neotremata, cardinal area discussed 304-305 classification of 321, 323 defined 294 distribution in Cambrian strata 316 evolution of genera of, discussed 319 holoperipheral growth of pseudodeltidium in 306 muscle scars compared with those of 06oZms 312,313 muscle scars discussed 312-313 pedicle tube discussed 314-315 surface ornamentation discussed 302 vascular markings discussed 311 Nepionic, defined 294 Nerike, Sweden, localities in 320ti, 320v, 320z Neuhof , Germany, locality at 303f Nevada, Barrel Spring section, in detail, listing included and cor- related species and localities 137-138 Cambrian species of, 1 isted 114-119 detailed section of Cambrian and Ordovician in, listing in- cluded and correlated species and localities 139-140 detailed section of Lower Cambrian in, listing included and correlated species and localities 137-138 INDEX. 849 Nevada— Continued. Eureka district section, in detail, listing included and cor- related species and localities 139-140 note on Middle and Upper Cambrian localities in 137 localities in n-m, ip, iv, 41, 7i-k, 7n, 7r, 7s, 7v, 7x, 7y, 7z, 8a, 8b', 8e, 8f, 8m-p, 8r, lOw, 14m, 30, 31, 31a, 31u, 52, 54, 55, 55b, 56, 57, 57b, 58, 59, 60, 61, 62, 62a, 63, 64, 65, 66, 174c, 175, 184, 201, 201a, 202, 203, 203a, 204, 205, 206a, 209, 211, 214a, 214b, 216a, 221, 313, 313a-k, 333, 333a^b species and localities in , compared with those of Utah 153-158 Nevado de Castillo, Argentina, locality at 389a Newberry, J. S., species named tor 784 newherryi, see Eoortltis. New Brunswicli:, Cambrian species of, listed 114-119 loealitiesin 2e_i_ jk-m, 2s-n, 2x, 2y, 3a, 3b, 300, 301, 301a-n, 301s-z, 308, 308a-l species and localities in, correlated with those of Cape Breton 131-135 Newfoundland, Cambrian species of, listed 114-119 detailedseetionof Cambrianin,listingspeciesand localities 140-141 localities in 1, la, 2, 2a, 3, 5 1-p, 5r, 5t, eg-i, 61, 6n, 6r, 6s, 6u-w, 6y, 41, 41a, 114, 114a, 114b, 314, 314a-i Manuels Brook section, listing species and localities 140-141 New Jersey, Cambrian species of, listed 114-119 locality in U^ New Mexico, Cambrianspecies of, listed 114-119 locaUtiesin 327, 327a-c Newport, Rhode Island, localities near 343,343a 343b Neivton, New Jersey, locality at ' u^ newtonensis, see Eoorthis. New York, Cambrianspecies of, listed 114-119 localities in (Lower Cambrian) 2b, 2d, 20, 20a, 21, 21a 22, 22a, 27, 27a, 29, 29a, 32, 32a, 33, 33b, 34, 34a, 35, 35k, 36,' 36b, 37, 37b, 38, 38a, 38c, 39, 39a, 43a, 44a, 44b, 45a, 45b 72' 72a, 338, 338a-h, 338k-q, 338x, 338y, 367, 367a, 367b, 3671, 3671 ?' localities in (Middle Cambrian) 3573 localities in (Upper Cambrian) 76, 76a, 77, 108, 109, 110, 110a, HI, 136, 185, 185a, 338], 338r-u, 338w, 367e-li, 367J-k, 392b locaUties in (Ordovician) 43, 338i, 338u, 338v, 338z, 367c note on stratigraphic position of localities in m New York Canyon, Eureka district, Nevada, locaUtiesin...".'.. 54, 65, 58 Nicholson, species named tor.. " J™, cno .,, , o^£, oyb nicholsoni, see Acrotrcta and Linguldla. Ninewells, near St. Dartds, South Wales, locaUty at 3i8p ninus, see Obolus tetonensis . Uisus, see MicromUra. Nisusia, described 725 articulating processes discussed 307 cardinal area discussed [ 304 305 cardinal process discussed 'ogg clarification ot ' " jjj 30- compared with BiUingsella " ' ^qq deltidium discussed.. ,n„ ,^. ,, jy(3 evolution discussed 319 320 evolution ot "" '017 general geographic and stratigraphic distribution of the species referred to ,„» general stratigraphic distribution and number of Cam- brian species and varieties of. jjj muscle scars discussed '" 3,, number ot species ot, in different types of sediment '.'.' I6O pedicle opening absent g.c pseudospondylium discussed 337 reference to, of Nisusia ? valicina 730 731 reference to, of Nisusia f (Jamesella f) kanabemis dis- cussed yg2 stratigraphic position mentioned " 3^3 type species " Orthisina festinata " .'.".'.".'.'.'."." .' .' .' ' 725 vascular markings not preserved 311 oZ5erta, described. . . _„„ ...-...,.,.....,... — ............. 725 compared with Nisusia rara Nisusia (Jamesella) lowi " Nisusia (Jamesella) nautes '" Nisusia (Jamesella) per pasta .' Nisusia (Jamesella) spencei general geographic and stratigraphic distribution tab^ '^;'"' 107 surface ornamentation discussed 302 type specimen figured !!.^!! PLC fig 3o 62667°— VOL 51, PT 1—12 54 729 733 734 736 73S Nisusia compta, described 727 general geographic and stratigraphic distribution tabu- '^"=<1 107 type specimen figured PI. XCVII fig 14 /es. 755 fissicosta, mentioned 772 flabdliies, compared with FhctortMs whitfieldi by Ulrich 308 "hicksi," compared with Eoorthis linnarssoni 783 discussed 755 "m.^a," compared with Nisusia f vaticiTia 730 jamesi, mentioned 772 "}:uthani," compared with Nisusia {Jamesella) "perpasta 736 "lenticularis," mentioned 731 "lenticularis? Kayser," discussed 767-768 "lynx," compared with Eoorthis primordialis 785 menapiie, compared with Eoorthis salteiisis 788 "parva Dalman," discussed 776 ^'pepina," compared with Clitambonites 739 discussed 749 "plicatella," type of Plectorthis Hall and Clarke 772 ^^primordialis," association mentioned 735 "remnicha," type of Eoorthis 773 "rominj/eri," compared with N isusia ? vaticina 730 compared with Nisusia {Jamesella) kuthani 733 "Orthis sp. Pompeckj " 793 "saltcTisis," compared with Orusia lenticularis 768 mentioned 499, 767 ^'sandbergi," type of Otusia 769 sinuata, mentioned 772, 7S5 "s/na^uZa," compared with Nisusia? vaticina,_ 730 mentioned 785 subquadraia, mentioned 772 tricenaria, American representative of Orthis callacfis 772 compared with Billin-gsella romingeri by Ulrich 303 Dalmanella suhxquatahy Ulrich 308 muscle scars of , discussed by Ulrich 308 See also Orthis callactis-tricenaria group. tTipHcatella, mentioned 772 tritonia, muscle scars of. discussed by Ulrich 308 '^vaticina Salter MS.," discussed 730,731 "sp. Kayser," discussed 767,768 discussed and compared with Orusia leriticularis 789 sp. Pompeckj, discussed 775, 793 *'Orthis (? Orthis christianise) Roemer," discussed 776 Orthis (BiUin^sella) laurentina, compared with Plectorthis whit- ficldi by Ulrich 308 Orthis {Dalmanella) parva, compared with Eoorthis 773 "Orthis (Finkclnburgia) finkelnburgi," type of Finkelnburgia 794 "Orthis (Plectorthis)," discussed 772 reference to, of BillingseUa retroflcxa discussed 761 reference to, of Otusia sandbergi discussed 770 Orthisina, compared with Kutorgina 579 Protorthis 739 reference to, of Eoorth is johannensis discussed 781 reference to, of iVwusia? m/idna discussed 730 reference to, of Nisusia {Jamesella) pellico discussed . . 735 "adscendeTis," compared with Nisusia {Jamesella) pellico .. 735 "festinata," type of Nisusia 725 " orientalis," compared with Eoorthis johannensis 781 "pepina," compared with Eoorthis johannensis 781 Orthoceras limestone, in generalized section for Sweden, Denmark, Finland, and Norway, listing species and localities 144 systemic reference discussed 98 Orthoceralite limestone (Passage beds), equivalent to the Vagi- noceras limestone 628 in generalized section for Russia, listing species and locali- ties 143 localities in 336d-f, 336z, 337, 337a-c, 337f-h, 337j-m, 390 Orthoids, canal system mentioned 312 Orthosirophia, classification of, by Ulrich 308 no Cambrian representatives 320 Orthothetes compared with Eostrophomena 796 Orthotichia, classification of, by Ulrich 308 Orusia, described 765 cardinal area discussed 305 classification of 321 evolution of 317 general geographic and stratigraphic distribution of the species referred to 108 general stratigrapliic distribution and number of Cam- brian species and varieties of Ill muscle scars discussed 313 number of species of, in different types of sediment 160 stratigraphic position mentioned 320 type species "Anomites lenticularis" 765 Ulrich on spondylium 308 vascular markings discussed 312 ? eurekensis, described "65 general geographic and stratigraphic distribution tab- ulated 108 type specimen figured PI. CI, fig. 7 lenticularis, described 765 compared with Orthis sp. Kayser 789 Orusia ? eurekensis 765 general geographic and stratigraphic distribution tab- ulated 108 tj'pe specimen not figured. lenticularis atrypoides, described 769 discussed 768 general geographic and stratigraphic distribution tab- ulated 108 type specimen figured PI. XCVIII, fig. 5 lenticularis lyncioidcs, described 769 discussed 768 general geographic and stratigraphic distribution tab- ulated ■ 108 type specimen figured PL XCVIII, fig. 4 lenticularis strophomenoides, discussed 768 Osceola, Nevada, localities near 8m, 8n, lOw Osceola, Wisconsin, localities near 78. 78b, 78c, 78s, 328b, 328m, 328n osccola, see Finkelnburgia and Lingulella mosia. osccola corrugata, see Finkelnburgia. Oslo, near Christiania, Norway, locality at 323m Osthammar, Sweden, localities near 311a, Slip See also Fanton Island. Ostra Rynninge, Sweden, locality at 320u Otis\'llle, Minnesota, locality at 339a Ottawa River, Quebec, locality on 392h Ottenby , Oeland Island, Sweden, localities at 310, 310r, 390e Otusia, described 769 cardinal area discussed 305 classification of 321, 325 evolution of 317 general geographic and stratigraphic distribution of the species referred to 108 general stratigraphic distribution and number of Cam- brian species and varieties of ill number of species of, in different types of sediment 160 reference to, of Otusia sandbergi discussed 770 stratigraphic position mentioned 320 type species "Orthis sandbergi" 769 Ulrich on spondylium 308 sandbergi, described 769 compared with Finkelnburgia finkelnburgi 794 Otusia utahen^is 770 general geographic and stratigraphic distribution tabulated ., 108 type specimen not figured. utahensis, described 770 general geographic and stratigraphic distribution tabulated 108 type sx>ecimen figured PI. LXXXIX, fig. 3 Ouray Cotmty, Colorado, localities in 335a, 360b Outside lateral muscle scars, sho\\Ti in figure 374 Outside and middle lateral (protractor) muscles, defined 294 ovalis, see Acrotreta. Ovando quadrangle, Montana, localities in 4q, 4q', 4v, 4w, 8j Oviedo, Spain, locality in 350a Owen, D. D., bibliographic references 22 species named for 523 weni, see Lingulella. 860 CAMBRIAN BRACHIOPODA. Owl Creek Mountains, Wyoming, locality in 302p Oxna (Oksna), Norway, locality at 323u pacifica, see Acrotreta. Pack, F. J., bibliographic reference 22 Packsaddle Mountain, Texas, localities on 68, 68e, 68y, 68z Paget limestone (Upper Cambrian), detailed section listing in- cluded species and localities 125 pagoda, see Eoorthis. Pagoda Hill, near Tsinan, China, locality at C56 Pahrump Valley, Nevada, locality near 7n (PalseoboliLs), see Obolus (^Pakeobolus). " Palxobolus bretonemis" type of Obolus (Palseoboliis) 378,426 paUialus, see Obolus. Palms, Esthonia, Russia, localities near 396j, 396m, 396p pandemia, see Obolus. Pander, C. H., bibliographic references 22 species named for 408, 652 pandcn, see Acrolhelc and Obolus. pannula, see Micromitra (Iphidella). pannula maladcTisis, see Micromitra (Iphidella). pannula opkirensis, see Micromitra (IpMdeUa). Panther Creek, Yellowstone National Park, Wyoming, locality near 302h papias, see EoortJiis. Parabolina zone, in generalized section for Cape Breton, listing in- cluded and correlated species and localities 131 mentioned 487 Paradise Dry Canyon, Cache County, Utah, localities in 31z, 32d, 32e, 55t Paradoxides, association mentioned 485, 555, 706, 730, 773, 809 Paradoiides beds, mentioned 499 Paradoxides fauna, mentioned 500 Paradoxides series, mentioned 516 ParaCris bluff, Adams County, Wisconsin, locality at 328k Rockbridge County, Virginia, locahties in 47a, 92b Rock Canyon, near Provo, Utah, locaUty in 7w Rock Creek, Granite Coimty, Montana, locahty on 3D2q Rock Hill sehoolhouse, near North Greenwich, New York, locah- ties near 33, 338c Rocky Gap, Vhginia, locality near 47h Rocky Mountain province, Cambrian species in, listed 114-119 Roemer, F., bibhographic references 23 Rogers, W. B., bibliographic references 23 species named for 465 Togersi,Bt& Obolus ( Westonia). Rogersville, Tennessee, locahties near 9, 9a, 12q, 101, 101a, 101b, 102, 102c, 103, 103a, 103b, 104, 121, 121a, 122, 123, 124, 124a, 374b Rogersville shale (Middle Cambrian), in generahzed section for Tennessee, Georgia, and Alabama, listingspecies and locali- ties 147 locahtiesin 101, IDla, 101b, 102. 121, 331 Rbhalla, Oeland Island, Sweden, locahty near 390d Rokitzan, Bohemia, locahty near 303b rokitzanensis, see Obolus. Rome, Georgia, locahties near 13c, 14, 96, 96b, 138a Rome formation (Middle Cambrian), in generalized section for Tennessee, Georgia, and Alabama,listingspeciesand locali- ties 147 locahties in 10a, 10b, 11, 13. 13b, 13c, 14, 14a, 103, 103a, 103b, 106, 107b, 138a Rome, (" Monte vallo") shale (Lower Cambrian), locahties in. 17b, 56c Rominger, C, bibliographic reference 23 species named for 763 romingeri, see BillingseUa. Rosses Bridge, near Essex, New York, locahty at 367h Ross-shire, Scotland, locahties in 316c, 316d Rost&uga, Sweden, locaUty near 309e Rostock, Germany, locality near 386g Rotherwood, Tennessee, locahty near 374d rotunda, see Lingulella. rotundata, see Syntrophia. rotundatus, see Obolus. Round Top Mountain, Eureka district, Nevada, locahty on 205 Rowe, R. B., speciesnamed for 55S rowci, see Lingulella (Lingu^epis). Ruby Hill, Eureka district, Nevada, locahties on 57, 57b rudis, see Acrotrcta. rugatus, see Obolus (Acritis). Tugosa,seeAcrotreta ophirensis and Schizopholis. rugosicostata, see Billingsella exporrccta. Russelokken, Norway , locahty at 323x Russia, Cambrian species of, listed 120-121 generahzed section of Cambrian and Ordovician in, listing species and localities 143-144 locahtiesin 9d, 311d-f, 311q-t, 311w-y, 336, 336a-z. 337, 337a-n, 395, 395a-z, 396, 396a-z species and varieties of Obolus and subgenera recognized by Mick\vitz in, listed 3S0 See also separate governments. Rust, William P., genus named for 327 Rustella, described 327 attachment of muscles in 309 classification of. 321,322 compared with Beecher's ideal "Paterina" 32S Curiicia 370 evolution discussed 318 evolution of 317 general geographic and stratigraphic distribution of the species referred to 98 general stratigraphic distribution and number of Cam- brian species and varieties of 110 number of species of, in different types of sediment . . 160 sl^ell substance 297 stage, mentioned 305 surface ornamentation discussed 301 ' type species Rustella edsoni 327 864 CAJMBRIAN BRACHIOPODA. Rustella cdsoni, described 327 cardinal area discussed 303 compared with Rustella 9 major 328 confused with Kuiorgvna. cingulata 323 evolution discussed 31S general geographic and stratigraphic distribution tab- ulated 9S most primitive brachiopod 316, 318 muscle scars discussed 312 type species of Rustella 327 type specimen figured PI. I, fig. 1 ? major, described 328 compared ^ith Obolus by Matthew 328 Rustella edsoni 328 generic reference questioned 327 general geographic and stratigraphic distribution tab- ulated 98 type specimen figured textfig. 19,328 Kustellacea, classification of 321 , 322 distribution in Cambrian strata 316 genera and species referred to, described 327-369 Rustellidse, classification of 321, 322 distribution in Cambrian strata 316 genera and species referred to, described 327-32S general stratigraphic distribution and number of Cambrian genera and species of 112 number of Cambrian genera and species of 112 number of genera and species in monograph 113 Rutland, Vermont, localities at and near 319w, 319x Rutland County, Vermont, localities in 319w, 319x Rutledge limestone, in gaieralized section for Tennessee, Georgia, and Alabama 147 Sabero, Leon, Spain, locality near 350 sabrinse, see Acrotreta. Sachuset Beach, near Newport, Rhode Island, locality on 343b Safford, J. M., species named for 747 saffordi, see WimaneUa. Saggad, Esthonia, Russia, locality at 396m sagittalis, see Acrotreta. sagittaUs magna, see Acrotreta. sagittalis taconica, see Acrotreta. sagittalis transversa, see Acrotreta. SaimaJd^ China, localitj' at 332 St. Albans, Vermont, localities near 16n, 319f, 319s " St. Albans formation" (Middle Cambrian), localities in 28a, 319s St. Charles limestone (Upper Cambrian), in detailed section in Blacksmith Fork, Utah, listing included and correlated species and localities 148-149 localities in 4y ^ 5a, 5c, Sim, 31n, 54b-g;, 54j, 54t, 54u, 54w, 54x, 55h, 56g St. Croix County, Wisconsin, localities in 79, 79', 79b, 79s, 328j St. Croix Falls, Wisconsin , locaUties at 82, 82s, 328e, 328h St. Croix River, Minnesota, locaUties on 97b, 339b, 364a St. Croix River, Wisconsin, localities on. . 78, 78b, 78s, 82, 82s, 328f, 364a "St. Croix sandstone," stratigraphic position of localities in discussed- 159 "St. Croix sandstone" (Middle Cambrian), localities in 79x, 83S 84, 84f, 84s. 97b, 328e, 328g, 339e "St. Croix sandstone" (Upper Cambrian), localities in.. lOv, 78, 78a-d, 78s, 79, 79', 79a, 79b, 79s, 80, 80a, 81, 81b, 81o, 82, 82a-c, 82s, 83, 83i, 83^ 84a, 85, 85a, 85s, 85z, S85x, 852, 86, 86a, 97, 97a, 97c, 97s, 97x, S97x, 98, 98a, 98x99, 99a, 100, lODa, 113, 116, 134, 134a, 135, 135b, 135c, 328, 328a, 328c, 328d, 328i-l, 328n, 328p, 328q, 339b, 339d, 339f-h St. Davids, South Wales, localities at and near 318d, 318g-j, 318n-r, 318w, 366b, 366c St. Davids Head, South AVales, locahty near 366 St. Francois County, Missouri, locaUties in llk-m, 369, 369a, 366c, 369g St. Fro, Oeland Island, Sweden, locality at 320s St. John, Orestes, bibliographic reference 23 St. John, New Brunswick, localities at and near 2e, 2s, 2t, 3b, 301e, 301g, 301k, 301n, 301t, 301u, 301w-z, 308, 308a-c, 308f, 308h, 308i St. John County, New Brunsmck, locaUties in 2e-i, 2k-m, 2s-u, 2x, 3a, 3b, 301, 301a-e, 301g-n, 301s-y, 308, S08a-c, 308e-i St. John formation (Middle Cambrian), locaUties in 301c, 301j, 301k St. John River, New Brunswick, locality on 2y, 300, 301f , 308d St. Lawrence County, New York, locaUty in 338w St. Lawrence formation (Upper Cambrian), locaUties in.. 328b, 339a, 364 localities in, mentioned 159 St. Lawrence River, Quebec, localities on 2n, 56a, 319h, 319 1, 319n-p, 319t St. Martins, New Brunswick, localities in 3011, 301m St. Petersburg, Russia, localities near 336, 336e, 336k, 336u, 336w, 336x, 336y, 337k, 337m, 395w, 395y, 396 1 St. Petersburg (Government), Russia, locaUties in 336, 336a, 336e, 336g, 336k, 3361, 336u, 336o, 336q, 336r, 336u, 336w-y, 337j , 337k, 337m, 395w, 395y, 395z, 396k, 396 1, 396z St. Piran sandstone (Lower Cambrian), detailed section listing species and localities 130 locality in 60b St. Simon, Province of Quebec, Canada, locaUty at 319b St. Timothy, Quebec, locality at 3i9t Sta. Benigna, Bohemia, locaUty at 303e Salem, New York, locaUties near 21, 37,37b, 43a, 45a salemensis, see BillingseUa. Saline Valley road, Inyo Coimty, CaUfomia, locaUties near.. 53, 312, 312a Salla, Esthonia,, Russia, locality at 337d SaUings Mountain, Virginia, locaUty on 47a Salmon River, Cape Breton, locality on 3ii Salta, Argentina, locaUty at 389 Salta (Province), Argentina, locaUties in 389, 389a, 389d saltensis, see JSoorthis. Salter, J. W., bibliographic references 23 species named for 425 Salter, J. W,, and Etheridge, R., bibliographic reference 23 Salter, J. W., and Hicks, H., bibliographic reference 23 salteri, see Obolus (Brbggcria). Salt Lake City, Utah, localities near 30a, 331, 55u Salt Lake County, Utah, localities in 30a, 33i, 55u Salt Range, India, locaUties in 15r, 357, 357a-d Salt\T.k, Aland Island, Finland, locality at 311x Sandberg, J. H., species named for 770 san4beriji, see Otusia. Sandby, Sweden, locaUties at 309i, 390g Sandomierz, Poland, locaUties near 368, 368a Sand Pass, Fish Spring Range, Utah, locality near 34i Sandstone, number of genera and species identified from leo Sandstone and limestone, number of genera and species common to both 160 Sandstone and shale, number of genera and species common to both 160 Sandstone, limestone, and shale, number of genera and species common to all three. lao Sandsvar, Norway, localities in 323i, 32Sr, 323s, 324b, 324c Sandy Point, Trinity Bay, Newfoundland, locality near 6y San Saba County, Texas, localities in 14g, 141, 353 San Saba River, Texas, locality on 353 Saratoga County, New York, localities in 76, 76a Saratoga Springs, New York, localities near 76, 76a Sardeson, F., bibliographic reference 23 Sardinia, Cambrian species of, listed 120-121 locaUties in 354, 354a-f species of Obolus from, listed 379 sardiniaensis, see Kutorgina. Sauk County, Wisconsin, localities in lOv, 80a, 81, 81b, Slo, 85, 85a, 85s, 116, 328, 328q Sawmill Creek, Meagher County, Montana, locaUties near 5f , 5k Sbirov, near Skrej, Bohemia, locality on brook of 345 Scapegoat Mountain, Powell Coimty, Montana, locaUties near 3j, 5j Scenidium , compared with Protorthis 739 Schelibourne, Nevada, localities near 7i, 313a, 313b, 313d, 313f ScheU Creek Range, Nevada, locaUties in 7i, 8e, 8o, 8p, 313a, 313b, 313d, 313f Scheilenberg, near Hof, Bavaria, locality at 303f Schizambon, described 622 classification of 321, 324 compared with Dearbornia 614 Trematobolus 313, 616 Trematobolus kempanum 619 evolution of 317 general geographic and stratigraphic distribution of the species referred to 104 general stratigraphic distribution and number of Cam- brian species and varieties of ill mentioned 620 number of Ordovician species and varieties of 113 number of species of, in different types of sediment. . . 160 surface ornamentation discussed 302 INDEX. 865 Schizambon—Conlinxied. type species Schizamhon iypicalis - - - - 622 vascular markings discussed 311 canadensis, discussed 622 ? dod^ei, discussed 622 duplkimuratus, discussed 622 ? esthonia, described 622 general geographic and stratigrapMc distribution tabu- lated 104 type specimen figured PI. LXXXIV, fig. 4 fissa, compared with Schizamhon ? esthonia 622 locket, discussed 622 manitouensis, described ' 623 general geogi-aphic and stratigraphic distribution tab- ulated 104 type specimen figmred PI. LXXXIV, fig. 3 priscus, described 623 general geographic and stratigraphic distribution tab- ulated 10-1 type specimen not figured. typicalis, described 624 compared with Schizamhon ? esthonia 622 Schizamhon manitouensis 623 • Schizamhon priscus 623 Siphonotreta f duhia 626 TTcmatoboliis kempanum 620 general geographic and stratigraphic distribution tab- ulated 104 type of Schizamhon 622 type specimen figured PI. LXXXrV', fig. la Schizocrania, compared with Discinolepis 664 compared with Mickwitzia 331 Schizopholis, described : - - - 608 cardinal area discussed 305 classification of 321,324 compared with Acrotreta 314 evolution discussed 319 evolution of 317 general geographic and stratigraphic distribution of the species referred to 104 general stratigraphic distribution and number of Cambrian species and varieties of 110 intermediate between Botsfordia and Acrotreta 602 number of spiecies of, in different types of sediment — 160 type species Schizopholis rugosa 609 rugosa, described 609 compared -with Botsfordia 602 general geographic and stratigraphic distribution tab- ulated 104 type of Schizopholis 609 type specimen figured PI. LXXXI, figs. 1, la-b Schizophoria , classification of by Ulrich 308 muscle scars of, discussed by Ulrich 308 Schizotreta, compared \vlth Kcyserlingia 628 elliptica, compared with Keyscrlingia 628 Schleswig-Holstein, Germany, locality in 386e Schmalensee, G., acknowledgments 12 mentioned 331 species named for 411, 709 schmalenseei, see Acrotreta and Oholus. Schmidt, Fr. .. acknowledgments 11 bibliographic references 23 mentioned 367 species named for 412 subgenus named for 442 schmidti, see Obolus. Schmidtia, compared with Leptembolon 378 (Schmidtia), see Oholus (Schmidtia). Schmidtia conglomerate (Upper Cambrian), in generalized sec- tion for Russia, fisting species and localities 143 localities in .'. . 395s-u '^ Schmidtia celata," tj^pe of Obolus (Schmidtia) 378,442 Schodack, New York, loeahties at 29a, 338 Schuchert, Charles, acknowledgments 13 bibliographic references 23 comparison of Lingulella and Lingulella (Lingulepis) b}' 544 genus named for 585 note on Cambrian spondylia and development of true orthids 308 species named for • '. . 531 terminology of 292 Schuchert, Charles [ WincheU, N. H., and], bibUographic reference- 26 schucherti, see Lingulella. Schuchertina, described 585 cardinal area discussed 304 classification of 321, 323 compared with Elkania 58 evolution and classification discussed 585 evolution discussed 319 evolution of ■- 317 general geographic and stratigraphic distribution of the species referred to 104 general stratigraphic distribution and number of Cam- brian species and varieties of.. 110 number of species of, in different types of sediment. . . 160 shell structure 297 stratigraphic position mentioned 318 Cambria, described 585 general geographic and stratigraphic distribution tab- ulated 104 surface ornamentation discussed 303 type specimen figured PI. LI, fig. 6b SehuchertinidFe, classification of, 321, 323 distribution in Cambrian strata 316 genera and species referred to, described 585 general stratigraphic distribution and number of Cambrian genera and species of 112 number of Cambrian genera and species of 112 number of genera and species in monograph 133 Schuylerville quadrangle, New York, localities in 35, 35a, 43, 338h, 3381, 338o, 338z Scipio, Utah, locality near 33 1 scotica, see Micromitra. Scotland, Cambrian species of, listed 120-121 generalized section of Cambrian and Ordovician in, listing species and localities 135-136 loeahties in 316, 316a-d only Lingulella from 541 sculptilis, see Micromitra. sculptilis endlichi, see Micromitra. Seal Point Cove, Trinity Bay, Newfoundland, locality at 6w Secondary vascular canals, shown in figure 374 Secret Canyon, Eureka district, Nevada, localities in 5515, 58 Secret Canyon road. Eureka district, Nevada, locality on 204 Secret Canyon shale (Middle Cambrian), detafied section, listing included and correlated species and localities 139 localities in 58, 60 Sections of brachiopod shells, preparation of 297 Sedgwick, A., bibliographic reference 23 Seebach, K. von, bibliographic reference 24 species named for 710 seebachi, see Acrotreta. Segerberg, C. O. [Moberg, J. C, and], bibhographic reference 21 Selwyn, A. R. C, species named for 414 selwyni, see Obolus. Septa, discussed 310 shown in figure 374 septalis, see Obolus. Septal plates, defined 295 sequens, see Lingulella (Lingulepis) acuminata. sera, see Acrothyra. Serpulite grit, in generalized section for England, Scotland, and Wales, listing species and localities 136 Sessile spondylium, defined 295 Set«,figured 362,374 Setal band, shown in figure 374 Shadow Canyon, Eureka district, Nevada, locality near 202 Shale, number of genera and species identified from 160 Shale and limestone, number of genera and species common to both . 160 Shale and sandstone, number of genera and species common to both 160 Shale, limestone, and sandstone, number of genera and species common to all three 160 Shaler, N. S., and Foerste, A. F., bibliographic reference 24 Shansi, China, localities in C37, C71, C72, C74, C75 shansiensis, see Obolus. Shantung, China, localities in CI- 7, C9, CIO, C12, C17, C20, C22, C23, C26, C28, C36, C45, C54, C56, C57, C61-64, C67, C68 shantung ensis, see Acrotreta. Sheep Creek, Wyoming, see Jackson Creek. Shelby County, Alabama, localities in 17b, 56c, 141a, 142, 164f shelh?/ ensis , see Wimanella. 62667°— VOL 51, ft 1—12- -55 866 CAMBRIAN BRACHIOPODA. Shell structure ■. 296-300 She U^bstance, generic importance of, in classification 297 Sliens i .China, localities in C32, C32' Sherbtooke limestcne (Upper Cambrian), detailed section, listing included species and localities 125 extension of upper boundary described 125 localities in 57d, 58f Sheridan, Wyoming, localities near 14k, 168, 171, 171a Sheridan County, Wyoming, localities in 14k, 168, 171, 171a, 302m Shimer, H. W. [Grabau, A. W., and], bibliographic reference 17 Shineton, England, locality at 304i Shineton Brook, England, localities on 3041, 304p Shineton shales (Upper Cambrian), in generalized section for England, Scotland, and Wales, listing species and localities . 135 localities in 304h, 3041, 304k, 3041, 304p Shipley Ferry, Sullivan County, Tennessee, locality near 2z Shipleys, Sullivan County, Tennessee, locality near 374c Shooks Gap, in Bays Moxmtains, Tennessee, localities in, . 10a, 10b, 106 Shocks Ridge, in Bays Mountains, Tennessee, locality near 106a Shropshire, see South Shropshire. Shumard, B. F., bibliographic references 24 Shumardia zone (Upper Cambrian), in generalized section for Sweden, Denmark, Finland, and Norway, listing species and localities 145 locality in 390b Shushan, New York, localities near 36, 338d Sias River, see Sjass River. Siberia, Cambrian species of, listed 121-122 locality in 347 Oholella cf. chromatica from, discussed 592 Siemiradzki, J. von, bibliographic reference 24 species named for 532 siemiradzkii , see Lingulella. Sierra Canyon, Eureka district, Nevada, localities in 62a, 65 Sierra County, New Mexico, localities in 327, 327a-c Sierra Springs, Eureka district, Nevada, locality at 56 Signal Mountain, Comanche County, Oklahoma, locality near 12j signalis, see Acrotreta. signata, see Acrotkyra and LiTtguIella. signata orta, see Acrotkyra. signata prima, see Acrothyra. Sillery, Upper (Ordovician), locality in 220a Siilery conglomerate bowlder (Lower Cambrian), locality in 56a siluricus, see Obolus {MickwUzclla). Silver Canyon, Inyo County, California, locality in 7 Silver Peak group (Lower Cambrian), localities in.. 11, Im, Ip, Iv, 1411 Silver Peak quadrangle, Nevada, localities in 11, Im, Ip, Iv, 7r, 7s, 7v, 7x, 7y, 7z, 8a, 8b', 8r, 174c, 175, 184 similis, see Lingulella. Simonds, near St. John, New Brunswick, locality in 301x simpler, see Lingulella and Wimanella. Simpson formation, locality correlated with 105x Simpson Range, Utah, localities in 32h, 32z Simpson Spring, Utah, localities near lis, 32h, 32z Simrishamn, Sweden, localities near 321u, 321v localities northwest of 8w, 3101, 320c, 320f, 3201, 320o, 320x, 321y, 390o sinoe, see Obolus. Sintai district, China, localities in Cl-7, C9, CIO, C12, C57, C61, C62, C63, 064 Sintaihien, China, locality near C57 Sinus, shown in figure 374 Sipkonotreta, described 624 classification of 321, 324 compared with Dearbornia 614 Tremaiobolus 313, 616 evolution of 317 general geographic and stratigraphic distribution of the species referred to 104 general stratigraphic distribution and number of Cam- brian species-and varieties of m number of Ordovician species and varieties of 113 number of species of, in different types of sediment . . . 160 reference to, of Sipkonotreta f dubia discussed 626 surface ornamentation discussed 302 type species " Crania un^uiculata " 625 ? dubia, described 625 general geographic and stratigraphic distribution tabu- lated 104 type specimen figured PI. LXXXI, fig. 7 Sipkonotreta fissa, discussed 622 "ladogensis,'* discussed 368,369 type of Helmcrscnia ..' 357 unguiculata, described 626 compared with Keyscrlingia 628 Sipkonotreta ? dubia 626 Sipkonotreta verrucosa 627 described and discussed 625 general geographic and stratigraphic distribution tab- ulated 104 type specimen not figured. verrucosa, described 627 compared with Ilclmersenia ladogensis 367 Sipkonotreta unguiculata 627 general geographic and stratigraphic distribution tab- ulated 104 type specimen not figured. Siphonotretacea, classification of 321, 324 distribution in Cambrian strata 316 genera and species referred to, described 5S6-630 Siphonotretidse, classification of 321, 324 distribution in Cambrian strata 316 evolution discussed ziq genera and species referred to, described 611-630 general stratigraphic distribution and number of (Cambrian genera and species of 112 number of Cambrian genera and species of. 112 number of genera and species in monograph 113 number of Ordovician genera and species in monograph U3 Sjass (Sias) River, St. Petersburg, Russia, locality on 336 1 Skalsternarne Island, near Gefle, Sweden, locality on 311o Skane, Sweden, locality in 310h See also Malmohus and Christianstad. Skara, Sweden, localities near... 309c, 309d, 320, 320a, 320b, 320n, 320y Skaraborg, Sweden, localities in. 309c, 309d, 310q, 320, 320a, 320b, 320e, 320h, 320m, 320n, 320r, 320y, 321q, 321r, 390f, 390j, 390k, 390n, 390p Sklirosen, Sweden, locality at ' By SkarpnS,to, Aland Island , Finland, locality at 311s Skiensdalen, Norway, locality in 324a Skrej, Bohemia, localities at and near 345, 345d-f , 345j, 345k Skrena, Norway, locality at 324a Slap, Bohemia, locality at 345h Slapnicky mlyn, near Skrej, Bohemia, locaUty at 345k Slapy, near Skrej, Bohemia, locality at forester house of 345d Slemmern, Aland Island, Finland, localities at 311f, 311q, 311y Slemmestad, Norway, localities at 8x, 323p Slough Creek, Yellowstone National Park, Montana, locality near. 302f Small Hill, Comanche County, Oklahoma, locality at 12j Smith, E. A., species named for 417 Smith, G. O., bibliographic reference 24 smitki, see Obolus. Smith Point, Trinity Bay, Newfoundland, localities on 5 1, 5n, 5o Smithsburg, Maryland, locahty near 47d Smith Sound, Trinity Bay, Newfoimdland, localities on 51, 511, 5o, 5s, 6y, 314b, 3141 Snake Range, Nevada, localities in 8n, lOw socialis, see Acrotreta. Soderarm lighthouse, near Norrtelje, Sweden, locality at 311u Sodra Mockleby, Oeland Island, Sweden, locality at 320p Solva, in generalized section for England, Scotland, and Wales. . . 136 Solva, South Wales, locaU ties at and near 318o, 318q, 318r South America, localities in 389, 389a-d See also Argentina. South Argyle, New York, locaUty near 3381 South AustraUa, Cambrian species of, listed 122 locahties in 315, 315a-d South Bessemer, Alabama, locaUty at 56o South Dakota, Cambrian species of, hsted 114-119 localities in 17j, 17k, 88a, 164, 165. 167, 355, 355a-f note on stratigraphic position of localities in 144 South Granville, New York, localities near 38, 367a South Shropshire, England, localities in 304h, 3041, 304k-l, 304p Spain, Cambrian species of, listed 120-121 locahties in 350, 350a, 350b Sparagmite sandstone (Lower Cambrian), in generalized section for Sweden, Demnark, Finland, and Norway,listingspecies and localities 146 locality in 8y spatula, see Lingulella (Lingulepis): INDEX. 867 Species, habitat of, discussed 159 zoological list of, giving page and plate references, and gen- eral geographic and stratigrapliic distribution 98-109 zoological list of Asiatic Cambrian, giving geographic distri- bution, by countries 121-122 European Cambrian, giving geographic distribution by countries 120-121 European Ordovician 123 North American Cambrian, giving geographic distri- bution by States and geologic provinces 114-119 North American Ordovician 122-123 South American and Australian Cambrian 122 Spence, R. S., species named for 737 spenceL, see Nisiisia (Jamesella). Spence shale (Middle Cambrian), apparent equivalent of, in de- tailed section in House Range, Utah, listing included and correlated species and localities 158 in detailed section in Blacksmith Fork, Utah, listing in- cluded and correlated species and localities 152 Spence shale member of the Ute formation (Middle Cambrian), localities in 31d, 32p, 541, 55c, 55e, 163 Spines, presence in Brachiopoda discussed 302 spinosa, see Acrotreta. Spirifer, mentioned 785 spissus, see Obolus (Liiigulobolus). Splanchnocoeie, defined 295 shown in figure 374 Spondylium, defined 295 discussed ■. ; 307-308 Schuchert on 308 Ulrich's notes on 308 Sponge Mountain, Llano County, Texas, locality near 14b Spring Creek, near Center, Alabama, locality on 95a Springer, Oklahoma, detailed section of Arbuckle limestone near, listing included and correlated species and localities . . . 141-142 localities near ■ 12k, ISm, 12n Spring Hill Canyon, Bridger Range, Montana, locality in 147a Spring Movmtain Range, Nevada, locality in 7n spurri, see^Acrothde. squamosa, see LinguleUa {Lingultpis). Sta. Benigna, Bohemia, locality at: 303e Stansbury Range, Utah, localities in 32f, 32g, 32j, 32k, 32o, 34u, 34v Staroja Ladoga, Novgorod, Russia, locality at 336j Starr, R. P., species named for 559 starri, see Lingulella (Limjukpis). Steel Ford, Cowan Creek, Alabama, •locality near 94 Stenotheca, reference to, of "Dlscina cvT/aiensis" discussed 723 Stephen, British Columbia, localities near 35c, 36g, 35h, 57c, 57g, 57k, 67s, 57y, 582 See also Mount Stephen. Stephen formation (Middle Cambrian), detailed section listing included and correlated species and fossils 127-128 localities in 14s, 35k, 57c, 67f, 57g, 57j, 57k, 57y, 581, 68], 58 1, 58r, 68w, 58z Stillwater, Minnesota, localities at and near...- 339, 339b Stissing, New York, locality near 367d stissingen^is, see Micromitra iPaterina). stissingensis ora, see Micromitra {Paterijia). Stissing Mountain, New York, locality on 32 Stockholm (Province), Sweden, locahties in 311a, 311p, 311u, 311v, 321, 321a-d, 321o StocMngford shales (Upper Cambrian), locality in 304j Stockport paper mill, Columbia Cotinty, New York, locahties near 29, 338b Stone, R. E., species named for 466 stoneanus, see Obolus ( M'estonia). Stoner, Pennsylvania, locality near 50 SJora Ror, Oeland Island, Sweden, localities near 310e, 310g, 390a Straits of Belleisle, Labrador, localities at 392a, 392e, 3921 Stratigraphic and geographic distril)Ution tabulated 98-109 Stratigraphic sections with correlated faunal lists 123-159 Streitberg, Esthonia, Russia, locality at 396r striata, see Bittingsella. Stricklandinia, compared with Syntropliia 798 f arachne, generic reference discussed 798 ? aretlmsa, generic reference discussed 798 SfropTiomcna, compared with Eostrophomena 796 reference to, of Eoortliis atava, discussed 774 Eoorthis johannensis, discussed 781 Protortliis hunnebergensis, discussed 741 Sfropftomcna— Continued, aurora, compared with Eostrophomena elegantula 796 rhomboidalis, compared with Eoortliis johannensis 781 "Strophomena or Strophodonta," compared with Eoorthis johan- nensis 781 "Strophomena(Eostrophomemi)elegantula," type ot Eostrophomena. 796 Strophomenacea, classification of 321, 325 distribution in Cambrian strata 316 genera and species referred to, described 795-796 Strophomenidfe, cardinal process, discussed 306 classification of 321, 326 cruralium, mentioned 309 distribution in Cambrian strata 316 genera and species referred to, described 795-796 general stratigraphic distriijution and number of Cambrian genera and species of 112 no interiors seen 312 number of Cambrian genera and species of 112 number of genera and species in monograph 113 Structure of the shell 296-300 sluarti, see Micromitra (Paterina). subconica, see Acrotreta. subquadrata, see Nisusia (JameseUa) perpasta. subsidua, see Acrothele. subsidua hera, see Acrothele. subsidua Ixvis, see Acrothele. Sularp, near Lvmd, Sweden, localities at 321s, 321t sulcata, see Acrotreta idahoerms and Eoorthis remnicha. sulcatus, see Discinopsis. Sullivan Cotmty , Tennessee, localities in 2z, 2z', 374c, 374e Summary tables 110-113 Stm River (North Fork), Powell County, Montana, localities near. 3j, 6j superba, see Micromitra (Paterina). Surface ornamentation, discussed 300-303 importance of, in classification 301 Sussex Cotmty, New Jersey, locality in lie Swallow ranch, Wliite Pine Coimty, Nevada, locality near 811 Swansea (Viola), Alabama, locality near 144c Swanston, W., bibliographic references 24 Swanton, Vermont, localities near 25a, 28, 319e, 319r, 319z swantonensis, see Micromitra (^Paterina) labradorica. Swantonia, described 796 cardinal area discussed 305 classification of 321, 326 compared with Camarella 797 evolution discussed 320 evolution of 317 general geographic 'and stratigraphic distribution of the species referred to 109 general stratigraphic distribution and number of Cam- brian species and varieties of Ill number of species of, in different types of sediment... 160 stratigraphic position mentioned 318 surface ornamentation discussed 303 type species " Camerella antiqua" 797 antiquata, described 797 compared with Huenella vermontana 809 general geographic and stratigraphic distribution tab- ulated 109 type specimen not figmred. weelcsi, described 797 compared with Swantonia antiquata 797 general geographic and stratigraphic distribution tab- ulated 109 type specimen figured PI. CIV, fig. 6 Swarow, Bohemia, locality at 303d Swasey formation (Middle Cambrian), in detailed section in House Range, Utah, listing included and correlated species and localities 7 157 locahties in llw, 30d Swasey Spring, House Range, Utah, localities near 15b, 15c Swasey Spring road. House Range, Utah, locality on lie Sweden, Cambrian species of, listed 120-121 generalized section of Cambrian and Ordovician in, listing included and correlated species and localities 144-146 localities in 8w, 8y, 8z, 9e, 309, 309a-f, 309h-j, 309 1, 309m, 310, 310a-z, 311, 311a-c, 311g-p, 311u, 311v, 320, 320a-z, 321, 321a-v, 321x-z, 323j, 323k, 390, 390a-p species of Obolus from, listed 379 stratigraphic position of bowlders in Baltic region discussed. 454 See also separate provinces. 868 CAilBRIAN BRACHIOPODA. SyDonj-mv, alphabetic index to 27-9S Syntropliia, described ■ "98 compared with Clarkclla S09 Diccllowu^ 572 Huenella S05 cruralium discussed 307. 309 evolution discussed 320 evolution of 317 general geographic and stratigraphic distribution of the species refeired to 109 general stratigraphic distribution and number ofCam- brian species and varieties of HI number of Ordovician species and varieties of 113 number of species of, In different types of sediment... 160 reference to, of HuencUa abnormis discussed 806 type species " Triplegia lateralis^' 798 sheU structiu-e compared with that of Huenella 300 spondy litun discussed 307 typical Cambrian species Syntrophia rotundata 798 Ulrich on spondylium 30S alata, described 799 general geographic and stratigraphic distribution tab- ulated 109 tjiie specimen figured PI. CIII, fig. 3a harabu^n^is, described 799 compared with Protorthis Jiekna ■ 740 SjjntTopliia primoTdialis 804 Syntroph ia unsia 805 general geographic and stratigraphic distribution tab- ulated 109 type specimen not figured. calcifera, described 800 compared with Clarkella moTitaTiensis 810 Stricklandinia 798 Syntrophia cambria SOI Syntrophia nundina 802 SyntropJtia pTimordialis 804 general geographic and stratigraphic distribution tab- ulated 109 surface ornamentation discussed 303 type specimen figured PL CIV, fig. Ic cambria, described 800 general geographic and stratigraphic distribution tab- ulated 109 type specimen figured text fig. 72B, 800 campbelU, described 801 general geographic and stratigraphic distribution tab- ulated : 109 type specimen figured text fig. 73 A, 801 lateralis, described ' 802 compared with Syntrophia rotundata 804 described in text following generic reference 798 general geographic and stratigraphic distribution tab- ulated 109 shell section figured text fig. 11, 299 r shell structure compared with that of Huenella ab- • normis ■ 300 type specimen not figured. nundina, described 802 compared with Syntrophia calcifera 800 SyntropTiia cambria 801 general geographic and stratigraphic distribution tabulated 109 type specimen figured PI. CII, fig. 4 arthia, described 803 general geographic and stratigraphic distribution tabulated 109 type specimen figured PI. CIV, fig. 4 primordialisy described 803 compared with Huenella bilUngsi 806 Syntrophia barabucnsis 799 Syntrophia calcifera'. 800 Syntrophia orthia 803 Syntrophia primordialis argia 804 Syntrophia unxia 805 general geographic and stratigraphic distribution tabulated 109 type specimen figured Pi. CII, figs. 2dand2e Syntrophia primordialis argja, described 804 general geographic and stratigraphic distribution tabulated i09 type specimen figured pi. CII, fig. 3 rotundata, described 804 compared with Clarhella montancnsis 810 Syntrophia campbelU 802 cruralium discussed 309 general geographic and stratigraphic distribution tabulated 109 has a descendant in Clarkclla montancnsis 810 spondylium or cruralium discussed 307 tj-pe specimen figured PI. CIII, fig. 4c t5T>ical Cambrian species of Syntrophia ^ 798 "texana," type of Huenella 805 ? unxia, described 804 general geographic and stratigraphic distribution tabulated 109 type specimen figured text fig. 74, 805 Syntrophiidce, classification of 321 . 326 distribution in Cambrian strata 3I6 genera and species referred to, described 796-810 general stratigraphic distribution and number of Cambrian genera and species of 112 number of Cambrian genera and species of 112 number of genera and species in monograph 113 number of Ordovician genera and species in monograph 113 septa discussed 310 Ulrich on spondylium 308 Systemic reference of formations discussed 98 taconica, see Acrotreta sagittalis. Tafern Hehg, North Wales, locality at 318k Tai-liirion, Wales, locaUty near 305e Taling, Cliina, locality at 332a Taquamenon Bay, Michigan, locality on 330 tarpa, see Lin^ulclla. Tate, R., bibliographic reference 24 species named for 789 taiei,see Eoorthis. Tatur Hill, Burnet County, Texas, localities on 67, 67c 67z Taylors Falls, Minnesota, localities near . : 82b, 339d, 339j Tazewell road, near Ivnoxville, Tennessee, locality on 118 Teeth, defined 295 Tejfovik, Bohemia, localities near 345a, 3451 Telotremata, defined 295 Temiscouata County, Quebec, localities in 2n» 3191 Tennessee, Cambrian species of, listed 114-119 generalized section of Cambrian in, listing included and correlated species and localities 147 locahties in 2z, 7d, 9. 9a, 10a, 10b, 11, 11a, 12, 12q, 13, 13b, 14a, 18, 101, 101a, 101b, 102, 102c, 103, 103a, 103b, 104, 105, 106, 106a, 107, 107a, 107b, 107o, 107u, 117, 117c, 118, 119, 121, 121a, 122, 122a, 123. 124, 124a, 128, 128a, 374, 374a-e tcnnesseensis, see LinnarssoncUri. Tepee Creek, Bighorn Moimtains, Wyoming, locality on 168 Terminology adopted 291 Terminology of different authors tabulated 292 Terrapin Creek road, near Center, Alabama, locality on 93a tetonensis, see Acrotreta microscopica and Obolus. fCtonensis leda, see Obolus. letonensis ninus, see Obolus. Teton Mountains, Wyoming, locahties in 4e, 4m, 4ii, 4o texana, see Eoorthis remnicha, Huenella, and Lingulella. texana Isciiusculus, see Huenella. Texas, Cambrian species of, listed 114-119 locahties in 14b, 14c, 14e, 14g, 14i, 14q, 14r, 67, 67c, 67zi 68, 68e, 68y, 68z, 69, 70, 70a, 70e, 71, 353, 353a-c note on stratigraphic position of localities in 148 Theca, association mentioned 707 themis, see Obolus ( Westonia). Theresa, New York, locahty near 185a Thermopolis, Wyoming, locality near 302p Thomas Mills, Floyd County, Georgia, locaUty near , 140a Thomas ranch, Juab County, Utah, localities near 15d, 33d, 34g Thomas Range, see Dugway Range. Threeforks quadrangle, Montana, localities in 4g, 4h, 41c, 4p, 149a, 150a, lE2a, i52b, 153,153a, 154, 155, 155a, 156b, 157, 158, 158a, 160, 160a, 302k, 302t, 340b INDEX. 869 tliyone, see Eoorthis. " Thysanotos," compared with "Acritis," "Embolus," and "Schmidlia, by Mickwitz *3* mentioned. 437 Ticonderoga, New York, locality near 367c Tihala, Esthonia, Russia, localities at 395a, 396h, 395d Tilcuya, Argentina, locality at 389b Timpahute Bange, Nevada, locality in 313g Tinghianghien, China, locality near C37 Tintic special quadrangle, Utah , localities in 34ii, 34s Tischer, Esthonia, Russia, locality at 39eh Toien, near Christiania, Norway, locaUties at 323 1, 323y, 323z Toll, E. von, bibliographic reference 24 Toll Gate Canyon, ^^Tnite Mountain Range, California, locaUty in.. 8ti Tombstone Gulch , near Bisbee, Arizon i, locahty in 14x Tomten, Norway, locaUty at 324 Tonto group (Middle Cambrian), localities in 73,73b, 74, 74b Tonto group (ITpper Cambrian), locality in 75 "Tonto" sandstone (Middle Cambrian), locaUties in 17c, 73a, 74c mentioned 422,516,524,553 "Tonto " shale (Middle Cambrian) , locaUty in 74d Tooele Coimty, Utah, locaUties in 3c-e, lis, 15p, 15x, 32f-h, 32], 32k, 32t, 32z, 33f, 34u, 34v, 329e Topsail Head, Conception Bay, Newfoundland, localities at 1, 2a, 41a, 314e Torettdla Ixoigala, stratigraphic position of bowlder containing, discussed *^' ^** torrentis, see Lingulella and Obolus. Torrybum, near St. John, New Brunswick, locaUties near 2s, 2t Tosterup, Sweden, locaUties at 310v, 323j, 323k, Towner's ranch, Lincoln County, Nevada, locaUty near 14m Town Knobs, Hawkins County, Tennessee, locaUties in 103, 103a, 103b, 122 Tradje, Sweden, locaUty at '■ 321ii Transmedian (rotator) muscles, defined 29o shown in figure 3i4 ransoersa, see Acrolreta sagUtalis, Linnarssonella, and Nimsiafes- tinata. Transverse axis, defined ^^ Trapezoidal area, defined 296 Tremadoc, Wales, locaUties at and near 305c, 305d, 318t, 3661 Tremadoc (Upper Cambrian), in generalized section for England, Scotland, and Wales, listing species and localities 135 Tremadoc, Lower (Upper Cambrian), locaUties in 305, 305c, 305£-j Tremadoc, Upper (Upper Cambrian), locaUties in. 305a, 305e, 366p, 366q Tremadoc shale ( Upper Cambrian) , locaUty in 318w Tremalis, compared with Discinolepis 664^ "pannulus," type species of Micromitra (,Iphidella) 369 Trewntobolus, described ^^^ articulating processes discussed 307 cardinal area discussed 305 classification of 321, 324 compared with Acrothele 631 Dearbornia 313. nii Oboldla 687, 588 Obolus 313 Scliizambon 313 Siplionotrela 313 YoTj:ia ? tvashingtonensis 613 evolution discussed 319 evolution of - - - - 31 7 general geographic and stratigraphic distribution of the species referred to 104 general stratigraphic distribution and number of Cam- brian species and varieties of HI number of species of, in different types of sediment . . 160 reference to, of Trcmatobolus ezcelsis discussed 615 shell substance 297 surface ornamentation discussed 302 tsTJespecies Trcmatoboljis insignis 616 vascular markings discussed 311 excelsis, described 617 cardinal area discussed 305 compared with Dearbornia darUi 615 Trcmatobolus kempanum 615 general geographic and stratigraphic distribution tab- ulated 104 oldest known brachiopod 316, 616 type specimen figured PI. LXXXII, fig. 8 Trcmatobolus insignis, described 617 described and discussed 018 compared with Tremalobolus excelsis 617 Trcmatobolus kempanum 616, 620 Trcmatobolus prisiinus , 616,621 YoTkia 611 general geographic and stratigraphic distribution tab- ulated 104 type of Trcmatobolus. 616 type specimen figured PI. LXXXIV, fig. 5 kempanum, described ^619 compared with Trcmatobolus excelsis 615,617 Trcmatobolus insignis 616, 618, 619 Trcmatobolus pristinus 621, 622 general geographic and stratigraphic distribution tab- ulated 104 type specimen not figmred. pristinus, described 621 compared with Trcmatobolus insignis 616,618,619 general geographic and stratigraphic distribution tabulated 104 type specimen figured PI. LXXXni, fig. 2t Trempealeau, Wisconsin, locaUties at and near 83, 83', 83S, 83S 135, 135b, 135c, 328g Trempealeau County, Wisconsin, locaUties in 79x, 83, 83', 83S, 831, 100a, 135, 135b, 135c, 328g triangularis, see Obolus. Trimerella, classification 310 compared with "Laklimina linguloides" 566 Neobolus warthi 566 development mentioned 561 Hall and Clarke on development of 309 mentioned 297 platform mentioned 309 "Undstromi," compared with Neobolus wartM 665 TrimereUidEe, development of 310 Trinity Bay, Newfotmdland, locaUties on 51, 5n, 50, 6g, 6h, 6w, 6y, 314, 314b, 3141 triparilis, see Lingulella. " Triplegia lateralis," described 798 type of Syntrophia 798 " Triplcsia primordialis," mentioned 798 Trois Pistoles, Quebec, age and relations of conglomerate at 350,351 locaUties at 2n, 3191 Trout Brook, Cape Breton, locality near 325a Trout Creek, near Manitou, Colorado, locaUties on 360a, 360g Troy, New York, fauna at, discussed 47'3-473 locaUties at and near 2b, 2d, 27, 27a, 44a, 338q, 367, 367b, 367i Troy quadrangle. New York, locaUties in 2b, 2d, 27, 27a, 44a, 338q, 367, 3671 Trubin, Bohemia, locaUty at - 303a Truth\ille, New York, locality near 38a Trwyn-y-Iago, North Wales, locaUty at 3051 Tschurskaja Station , Siberia, locaUty near 347 Tsinan, China, locaUties near-. C54, C56, C67 TuUberg, S. A., species named for 790 tullbergi, see Eoorthis. tumida, see Lingulella. Tungyu, China, locaUty near C71 Turkeytown, Alabama, locality near 1*5 Turner, H. W., bibliographic reference. 24 species named for 660 turneri, see Acrothele. Tilrsel, Esthonia, Russia, locaUty at 337f Twobit, Black Hills, South Dakota, locaUty near 17k Twomile Canyon, near Malade, Idaho, locaUties in 4y, ■ 5a-c, 5h, 54s, 54t-x, 55d Tyler Springs, House Range, Utah, locality near 8k typicalis, see Scliizambon. Uinta County, Wyoming, locaUties in 4e, 4m-o, 302d, 302t Uinta Mountain upUtt, sediments derived from . . . . ; 148 Ulrich, E. O., acknowledgments 13 on spondylia of Cambrian and Ordovician Protremata 308 species named for - 714 ulrichi, see Acrotreta. ^ Umbo, defined 296 Umbonal ca-snty , defined — 296 Umbonal muscle, defined 296 Umbonal muscle discussed 313 870 CAIIBRIAN BRACHIOPODA. IT mbonal muscle scar, sho^^•n in figiiro 374 Umhonal slopes defined 290 undosa, see Micromilra (Paterina). unguiciilata, see Siphonotreta. " UnguJa ovata," mentioned 383,444 Ungulite grit (Upper Cambrian), in generalized section for Russia, listing species and localities 143 localities in 336h. 336o, 336p, 336q Union County, Tennessee, locality in 11a United States Geological Survey, acknowledgments 13 unxia, see Syntrophia. vpis. see LingulcUa. uplandica, see Acrotrela. uplandica limoensis, see Acrotreta. Upper Cambrian. Alabama, generalized section, listing included and correlated species and localities 147 Alberta, fossil horizons correlated with those of British Columbia 125-126 British Columbia, detailed section, listing species and lo- calities -■ 125-126 British Columbia, upper boundary extended : 125 Cape Breton, generalized section, listing species and localities. 131 Denmark, generalized section, listing included and correlated species and localities 145 England, generalized section, listing species and localities. 135-136 families listed - - ■ 112 Finland, generalized section, listing included and correlated species and localities 145 genera listed : 110-111,317 Georgia, generalized section, listing included and correlated species and localities 147 Missouri, generalized section, listing species and localities.. . 137 Nevada, detailed section, listing species and localities 139 New Brunswick, species and localities in, correlated with those of Cape Breton 131 Newfoundland, detailed section, listing species and locali- ties 140 Norway, generalized section, listing included and correlated species and localities 145 Oklahoma, detailed section, listing species and localities 142 Russia, generalized section, listing species and localities. . . 143-144 Scotland, generalized section, listing species and localities. 135-136 species listed 98-109 Sweden, generalized section, Hsting included and correlated species and localities 145 Tennessee, generalized section, listing included and corre- lated species and localities 147 Utah, detailed section, listing included and correlated spe- cies and localities 148-149, 153-154 Wales, generalized section, listing species and localities 135-136 Upper Ffestiniog group, in generalized section for England, Scot- land, and AVales, listing species and localities 135 Upper Leitehes Creek, Cape Breton, localities near 8d, lOe-h, lOm. 372, 372a Upper Lingula flags, in generalized section for England, Scotland, and Wales, listing species and localities 135 Upper "Linsenschicht," m generalized section for Russia 143 urania, see Linnarssonella. Utah, Blacksmith Fork section, in detail, listing included and cor- related species and localities 148-153 Cambrian species of, listed 114^119 detailed sections of Cambrian and Ordovician in, listing included and correlated species and localities 148-158 House Range section, in detail, listing included and corre- lated species and localities 153-158 localities in 3c-e, 3s, 3t, 3w-y, 4, 7w, 8g, 8i, 8k, lOy, lOz, lln-q, lis, llu, llw-y, 14t, 14v, 15b-d, 15p, 15x, 30a, 30c, 30d, 30e, 30g, 30h, 30j-q, 30s, 30u, 30w, 30y, 30z, 31c-e, 31h, 31 1-n, 31q, 31s, 31t, 31v, 31y, 31z, 32c-k, 32n-p, 32t, 32x-z, 33d. 33f, 33i, 33j, 33 1, 33n, 33r, 33t, 34g, 341, 34m, 34n, 34q-v, 54a-r, 54y, 55e, 551i, 55n, 55t, 55u, 105t, 105x, 1852, 329, 329a-e Utah County, Utah, locality in 7w utahensis, see MicTomitra (Paterina) labTadoTica, Nisusia (James- ella), and Otusia. Cite limestone (Middle Cambrian), in detailed section in Black- smith Fork, Utah, listing included and correlated species and localities 150-152 localities in 31c-e, 31z, 32e, 32p, 54a, 54 1-p, 547, 55c, 55e, 55t, 59f, 59g, 163 Ute Peak, Cache County, Utah, locality near 329a See also Paradise Dry Canyon and Blacksmith Fork. Vaskkero, Norway, locality at 323g "Vaginatenkalk" (Ordovician), in generalized section for Russia, listmg species and localities 143 localities in 336z, 337, 337a-c, 337f, 337^ "Vaginatiun limestone" (Passage beds), localities in 396n, 396p Vaginoceras limestone, equivalent to the OrthocerafUe limestone. . 628 in generalized section for Russia, listing species and localities. 143 Valatie Ivill, Rensselaer County, New York, locality on 44a Valbom, see Monte de Valbom. Valcalda Spring, Esmeralda County, Nevada, locality near Iv Valley Creek bridge, Bessemer, Alabama, locality near 56u Van Ness quarry, Lodi, Wisconsin, locality at 86 Vanuxem, L., bibliographic reference 24 varians, see Orbkuloidea. Vascular canals, shown in figure 374 Vascular markings, discussed 311-312 Vascular (pallial) sinuses, defined '. 296 variation in position of, in Obolus and Lingulella, and their subgenera 376-377 Vassar College, near Poughkeepsie, New York, locality near 367e Viistergotland, see Skaraborg, Wermland, etc. vaticina, see Nisusia. Ventlinge, see Wentlinge. Ventral valve, defined 296 explanation of absence in collections of Trematobolus 617 vermilionensiSj sec Oholella. Vermilion Pass, Alberta, locality in 60b Vermont, Cambrian species of, listed 114r-119 locaUtiesin 16n, 25, 25a, 26, 28, 28a, 87, 227, 319e-g, 319j, 319k, 319m, 319q-s, 319v-z, 392o, 392p ■ note on stratigraphic position of localities in 159 vermontana, see Huenella. de Vemeuil, E. P., bibliographic reference 24 de Vemeuil, E. P., and Barrande, J., bibliographic reference 24 Vernon, Utah, localities on stage road west of lis, 32h, 32t, 32z, 33f verrucosa, see Siphonotreta. Vestergotland, see Skaraborg, Wermland, etc. Vestfossen, Norway, localities at 323f , 323h, 323ii Villa Boim, Portugal, locaUty near 351 ' villaboimensis, see Acrothele. Vinala, Sweden, locality at 320v Viola, see Swansea (Viola). Virginia, Cambrian species of, listed 114-119 locahties in : 47a, 47c, 47h, 92b, 331 note on stratigraphic position of localities in 159 Visceral area, defined 296 Visceral cavity, defined 296 Vistula River, Poland, localities on ■- 368, 368a, 386e Volborth, A. von, bibliographic reference 24 genus named for 366 species named for 419 volborthi, see Obolus. Volborthia, described 365 classification of 321,322 evolution discussed 318 evolution of 317 false cardinal area mentioned 318 general geographic and stratigraphic distribution of the species referred -to 99 number of Ordovician species and varieties of 113 number of species of, in different types of sediment- . 160 surface ornamentation discussed 301 type species ' 'A crotreta recurva " 366 recurva, described 366 general geographic and stratigraphic distribution tabulated 99 pedicle opening in, discussed and figured 366 type specimen figured PI. I, figs. 6, 6a-e Volkhof (Wolchow) River, St. Petersburg, Russia, localities on. , 336k, 336r, 336x, 337j, 337k, 396k Vrana, Sweden, locality at 320v Waagen, W., bibliographic references 24 Wabasha County, Minnesota, localities in 97, 97x, S97x, 99, 131, 339c, 339f, 339h Wades Gap, Alabama, locality near 139a Wahlenberg, G., bibliographic reference 24 Wahwah Mountains, Utali, localities in 34r, 34t Wah wah Spring, U tah, localities near 34r, 34t INDEX. 871 Walcott, B. S., species named for 355 Walcott, C. T>., bibliographic references 24, 25 Walcott, Mrs. C D., species named for 740 Waldhdmia, cardinal process discussed 306 Wales, Cambrian species of, listed 120-121 generalized section of Cambrian and Ordovician in, listing species and localities 13.5-136 localities in 305, 305a, 305c-i, 318, 318a-w, 366, 366a-s Walker's ranch, Lewis and Clark County, Montana, locality near. 9in Wallace switch, near Bristol, Tennessee, locality at Sz' Wallerius, I. D., bibliographic reference • 26 Wanner, Atreus, species named for 613 wanneri, see Yorkia. • wanniecki, see Lingulella. wapta, see MicromitTa {Paterina). Wapta Peak, British Columbia, locality near 35k Warth, H., species named for 567,772 wuTthi, see Neobolus and Wynnia. Warmckshire, England, locality in 304j Wasatch Canyon, north of Brigham, Utah, localities in 32p, 32x, 33j, 34q, 54k, 54q, 55e, 105x wasatchensis, see Oholus ( Westonia). Wasatch Mountains, Utah, see Wasatch Canyon, Calls Fort, Brigham, Geneva, Blacksmith Fork, Paradise Dry Can- yon, Patterson, Ogden Canyon, Provo, Big Cottonwood Canyon, Mona, Weber Canyon, etc. Washington, see Mount Washington. Washington County, Maryland, localities in .- . . 16f , 47d-f Minnesota, localities in 339, 339a, 339b Missouri, localities in lie, 369b, 369d New York, localities in _ 20, 20a, 21, 21a. 22, 22a, 33, 33b, 34, 34a, 35, 35a, 36, 36b, 37. 37b, 38, 38a, 38c, 39, 39a, 43, 43a, 45a, 45b, 109, 110, 110a, 338a, 338c-i, 338 1, 338m, 338o, 338p, 338v, 338x, 338z, 367a, 367k, 367 1 washingtonejisis , see Yorkia. Waterfall Valley near Maentwrog, North Wales, localities in . 318 1, 318m Waucoba Springs, Inyo County, California, localities near. 53, 312, 312a Waucoba Springs section, 3b (Lower Cambrian), locality in « 312a WaucobaSprings section, 3d (Lower Cambrian), localitiesin . 53, 53a?, 312 Waynesboro, Pennsylvania, locality near 49d Weber CaJiyon, Morgan County, Utah, locality in 329c Weber County, Utah, localities in 30p, 30q, 30s Webs Ridge, Tennessee, locality on 12 Weed, W. H., bibliographic, reference 26 Weeks, F. B., acknowledgments 13 Weeks Canyon, House Range, Utah, localities in 30n, 30n', 30o weeksi see Swanionia. Weeks limestone (Middle Cambrian), in detailed section in House Range, Utah, listing included and correlated species and localities 154-155 localities in 30n, 30n', 30o mentioned 510 Wehlau, East Prussia, localities near 386b, 386t Weichsel, see Vistula. Weisner quartzite (Lower Cambrian), in generalized section for Tennessee, Georgia, and Alabama, listing species and locali- ties 147 locality in , 59in Weller, Stuart, bibliographic reference 26 species named for 539 welleri, see Linguleila. Wentlinge, Oeland Island, Sweden, locality at 390c Wermland, Sweden, locality in 321p Wern, North Wales, locality at 305g Westerg^rd, A. H., bibliographic reference 26 Westergotland, see Skaraborg, Wermland, etc. West Gallatin River, Montana, localities on 4g', 4h, 4k, 4p, 156b, 159, 161, 302, 302h, 302j West Prussia, localities in 386d, 386 1 Weston, T. C, subgenus named for 451 Westonia, type of surface discussed % 301, 302 (Westonia), see Oholus (Westonia). Weymouth, sec North Weymouth. Wheeler Amphitheater, House Range, Utah, localities in 3s, 3t, 3x, 3y, 4, 8g, llq, llx, lly, 30g Wbeeler formation (Middle Cambrian), in detailed section in House Range, Utah, listing included and correlated species and localities 156 localities in 3s, 3t, 4, 8g, llu, 15b White, C. A., bibliographic references 26 Whiteaves, J. F., acknowledgments 12 bibliograpliic reference 26 species named for .- 571 mentioned 335 whiteavcsi, see Bicia. ■\Vhitechiu:ch, St. Davids, South Wales, locahty near 318q Whitehall, New York, locaUties near.. .. 20a, 34, 39, 45b, 110, 110a, 338m Whitehall quadrangle. New York, localities in 34, 39, 45b', 110, 110a, 338a, 338m White Leaved Oak, England, locality at 304 White Leaved Oak shales -(Upper Cambrian), in generahzed section for England, Scotland, and Wales, listing species and localities 135 locahties in 304b, 304e, 304f Wbite Mountain Range, California, Kutorgina pcrugata from, discussed 5S4 locahties in 7, 8b White Pine, White Mountain Range, California, locality near 8b White Pine County, Nevada, localities in 41, 7i, 8e, 8f, 8m-p, lOw, 214a, 214b, 313, 313a, 313b, 313d-f, 313k? Wliite Pine district, Nevada, localities in 214a, 214b, 313k Whitesand Bay, near St. Davids, South Wales, locality at 366 Whitfield, R. P., bibliographic references 26 species named for 764 AYhitfield, R. P. (Hall, J., and), bibliographic reference 18 whitfieldi, see Billingsclla. Whyte, see Mount Whyte. wichitacnsis, see Eoorthis. wicliitacTisis Ixuiusculus, see Eoorthis. Wiems, Esthonia, Russia, locaUty at 336t Wieser, Frances, acknowledgments 13 Wilhams Canyon, Manitou, Colorado, localities in 186, 186a Williard, T. E., species named for. 358 williaTdi, see Micromitra (Paterina). Willis, Bailey, acknowledgments 12 species named for 420 WiUis, Bailey, and Blackwelder, Eliot, bibhographic reference — 26 willisi, see Obolus. Willow Creek, Gallatin County, Montana, locality on 160 Willow River., near Hudson, Wisconsin, locaUty on 328j Wiman, Carl, acknowledgments 12 bibhographic reference 26 genus named for 745 species named for 792 Wimanella, described 745 absence of vascular or muscle markings in, discussed- . 748 classification of 321, 325 evolution discussed 320 evolution of 317 general geographic and stratigraphic distribution of the species referred to 107 general stratigraphic distribution and number of Cam- brian species and varieties of Ill number of species of, in different types of sedi- ment ■ 160 reference to, of Wimanella inyoensis discussed 747 stratigraphic position mentioned 320 type species Wimanella simplex 745 ? anomala, described 745 compared with Billingsella appalachia 750 Wimanella sfielbyensis 748 general geographic and stratigraphic distribution tab- ulated 107 type specimen figured PI. LXXXVII, fig. 1 Tiarlanensis, described 746 compared with Billingsella coloradoensis 745 Billingsella plicatella 745 Wimanella saffordi 747 general geographic and stratigraphic distribution tab- ulated ■ ■ ■ ■ - 107 t5T)e specimen figured PI- LXXXVII, fig. 5b inyoensis, described 746 general geographic and stratigraphic distribution tab- ulated 107 type specimen figured text fig. 63A, 747 saffordi, described 747 general geographic and stratigrapliic distribution tab- ulated .- 107 type specimen figured PI. LXXXVII, fig. 7 872 CAJVmRIAN BRACIIIOPODA. M'imamlla shelbycnsis, described "47 general geographic and stratigraphic distribution tab- ulated 107 tM)e specimen figured PI. II, fig. 9 simplex, described 748 compared with Wimanella shelbycnsis 748 general geographic and stratigraphie distribution tab- ulated 107 type of Wimanella 745- type specimen figured PI. LXXXIX, fig. 2 wimani, see Eoortliis and Obolus ( M'estonia). Winchell, A., bibliographic reference 26 Winchell, N. H. , bibliographic reference 26 Winchell. N. H., and Schuchert, C, bibliographic reference 26 Windjuelandet, Norway, localities at 323b, 324d Winfield, "Wisconsin, localities at and near.. 97a, 97c, 328a tvinfieldenMs. see Eoorthis remnicha. "Wing, Augustus, species named for 743 wingi, see Protorthis. Winona. Minnesota, localities near 339g. 339k winona, see Lingulella. wmona convexa, see Lingulella. "Winona County, Minnesota, localities in. . . . 84, 84f, 84s, 99, 339f-h, 339k Wirrialpa, South Australia, localities at 315b-d wirrialpensis, see Obolella. wirthi, see Lingulella. Wisconsin, Cambrian species of. listed 114-119 localities in . . lOv, 78, 78a-d, 78s, 79, 79', 79a, 791), 79s, 79x, 80, 80a, 81, 81b, 810, 82, 82a, 82s. 83. 83', 85, 85a, 85s. S5e, S85x, 85z, 86, 86a, 97a, 97c, 98, 98x, 99a, 100, 100a, 116, 134, 134a, 135, 135b, 135c, 328, 328a-n, 328p, 328q, 364, 364a note on stratigraphie position of localities in 159 Wismar, Germany, locality near 386f Wolchow. see Volkhof. Woleschna, Bohemia, locality near 303h Wolf Creek, Bighorn Mountains, AVyoming, locality on 14k Wolf Creek, Virginia, locality on 47h Wolsey, Montana, localities near 5f, 5k, 340 AVolsey shale (Middle Cambrian ) , localities in 4x, 5f note on stratigraphie position and correlation of 137 Wood, Elvira, acknowledgments 13 Wood Cone, Eureka district, Nevada, localities on 203, 203a, 211 Woodstock, Alabama, locality near 90b W^ood worth. J. B., species named for 661 woodwoTthi. see AcTothele. Worcestershire, England , localities in 304, 304a, 304b-g Wormditt, East Prussia, locality near 386k Worthen, A. H., species named for 421 wortheni, see Obolus. Wraz, Bohemia, locality at 303n Wutaihien, China, locaUty near C75 Wynantskill, New York, localities near 72a, 33Sk Wynne, Arthur B., genus named for 7 771 Wynnia, described 771 cardinal area discussed 305 classification of 321, 325 evolution of 317 general geographic and stratigraphie distribution of the species referred to 108 general stratigraphie distribution and number of Cam- brian species and varieties of Ill number of species of, in different types of sediment ... ICO stratigraphie position mentioned 320 warthi, described 771 general geographic and stratigraphie distribution tabulated lOS type specimen figured PI. LXXXIX, fig. 4a Wyoming, Cambrian species of, listed - 114-119 localities in (Middle Cambrian) 4e, 4j, 4m-o, 170, 171, 171a, 302b, 302 I, 302m, 302o, 302x, 302y, 340c, 340d localities in (Upper Cambrian) 14k, 168, 302c-e, 302g-h, 302p, 302u note on stratigraphie position of localities in 144 stratigraphie position of localities in, discussed 137 Wysogdrski, Johann, biljliographic reference 2G Yancoys Bend, Coosa River, Alabama, locality at 92x Yellowstone National Park, Wyoming, localities in 4j, 302b, 302c, 302f-h, 3021 Yellowstone River, Montana, locality eSst of 4r Yenchaung, China, localities at and near Cl-7, C9, CIO, 012, C61, C62, C63, C64 Yogo limestone (Upper Cambrian), localities in 302q, 302r note on stratigraphie position of 1 37 York, Pennsylvania, localities at and near. 8q, 48d, 49a, 49e, 50, 50a, 346c York County, Pennsylvania, localil ies in 8q, 48d, 49, 49a-c, 49e, 49w, 50. 50a, 346, 346c yorkensis, see Acrotliele. Yorke Peninsula, South Australia, localities on 315, 315a Yorkia, described 611 cardinal area discussed 305 classification of : 321, 324 compared \vith Quebecia 611 evolution discussed 319 evolution of 317 general geographic and stratigraphie distribution of the species referred to 104 general stratigraphie distribution and number of Cam- brian species and varieties of Ill muscle scars not shown in 313 number of species of, In difl'erent types of sediment . . . 160 reference to, of yorkia ? miqueli discussed 612 reference to, of yorkia ? orientalis discussed 612 reference to, of yorkia? washingtonen^is discussed,., 612,613 shell substance 297 stratigraphie position mentioned 318 type species yorkia wanneri 611 vascular markings discussed ; 311 ? miqueli, described .^ 611 general geographic and stratigraphie distribution tabu- lated : 104 type specimen figured PI. LX XXII. fig. 4 , ? orientalis, described 612 general geographic and stratigraphie distribution tabu- lated 104 tj-pe specimen figured PI. LXXXII, fig. 3 wanneri, described 612 compared with yorkia ? orientalis 612 general geographic and stratigraphie distribution tabu- lated 104 type of yorkia 611 type specimen figured PI. LXXXII, fig. Ig ? washingtonensis, described 613 general geographic and stratigraphie distrbution tabu- lated 104 generic reference discussed 612 type specimen figured PI. LXXXII, fig. 2 Youngs Creek, Ovando quadrangle, Montana, localities near 4q, 4q',4w, 8j Youngs (McPhees) Point, Nova Scotia, locality on 307d Ytternaset, Aland Island, Finland, locahties at 311q, 311y Zarskoe Selo, St. Petersburg, Russia, localities at 336g, 396z Zbirov, see Sbirov. zeno, see Eoorthis, zenobia, see Micromitra. zetus, see Obolus. zeus, see Lingulella. Ziegelskoppel , Esthonia, Russia, locality at 396t Zittel, K. A. von, bibliographic reference 26 Zone Blllaor Bill/? (Ordovician), locality in 337j Zone C of Westerg^rd (Passage beds), locaUty in 310w Zone 1 of Moberg and Segerberg (Upper Cambrian), locality in. . . 309b Zone 2 of Moberg and Segerberg (Upper Cambrian) , locaUty in. . . 309a Zone 3 of Moberg and Segerberg (Upper Cambrian), localities in 390b, 390c i See also Shumardia zone and Ceratopyge slate. Zone 4 of Moberg and Segerberg (Passage beds), localities in . . . 309, 310 See also Ceratopyge limestone. Zoological discussion 291-326 zoppi, see Obolus. r^