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Additional comments:/ Commentaires suppi^mentaires: L'Institut a microfilm^ le meilleur exemplaire qu'il lui a 6ti possible de se procurer. Les ddtaiis de cet exemplaire qui sont peut-Atre uniques du point de vue bibliographique. qui peuvent modifier une image reproduite, ou qui peuvent exiger une modification dans la methods normale de filmage sont indiqu6s ci-dessous. I I Coloured pages/ D Pages de couleur Pages damaged/ Pages endommagies Pages restored and/oi Pages restaurdes et/ou pellicul6es Pages discoloured, stained or foxec Pages ddcoiordes, tachet6es ou piqudes Pages detached/ Pages d6tach6es Showthrough/ Transparence Quality of prir Qualiti in6gale de I'impression Includes supplementary materit Comprc' 4 " STUDIES ON THE CAMBRIAN FAUNAS OF NORTH AMERICA BY CHARLES r>OOLITTLE WALCOTT WASHINGTON GOVERNMENT PRINTING OFFIOB 1886 Letter of tri Inti'otliictnrj Review « borizo] Sniiimar. On t\ui 11 Aeknowl Description < Fiicoidnl Hjidngia) I'icliiuodc Hiachiup LiiiiKtllib (laNteropi Ft(irop()(l I'o'cilopoi Description o Index Since the t< used for a ge ueric name wi CONTENTS. PaC«w Letter of transmittal 7 Introductory observations 11 Review of tho strata and faunas referred to the Middle Cambrian or Georgia horizon 12 Sninmury of I lie Caniliriau faunas of North .'.nierica 59 Oil thtt use of the name Taconic 65 Aclmowledgmonts 71 Description of the Middle Cambrian fauna 72 Fiicoidal remains, trails of annelids, &c 72 ■Spongio) 72 Kdiinodermata 94 Itruchiopoda 9o liiiincljibrnnchiata 123 CiaHteropoda 126 Ftrropoda 131 Pd'cilopoda 149 Description of n Ptfcropod from the Upper Cambrian or Potsdam horizon 223 Index 357 Ml i- NOTE. Since the text of this bulletin was written, the generic name BiUingsia has been used for a genus of brachiopods (Amer. Jour. Sci., June, 1886, p. 466). Another ge- neric name will be proposed for the name as used in this bulletin. (731) 6 ma i ';! 5-fi ' f i Fig. 1. ILLUSTRATIONS. Platr I. SpongitB '. asn* II. Spongiw 'J31 III. Spongise 835 IV. SpoDRiBB aao V. S|M>ugi(e 243 VI. Spongiiu nnd Echinodermata 247 VII. BrachloiMMla 251 VIII. Brachiopoda aud Crustacea 255 IX. Brachiopoda 25» X. Brachiopoda 26S XI. Brachiopoda and Hydrozoa 267 XII. OaHteropoda and Pteropoda 271 XIII Pt«ropoda 275 XIV. Pteropoila 279 XV. Crustacea 283 XVI. Pojcilopoda 287 XVII. Pmcilopotl 291 XVIII. PoBcilopoda 295 XIX. Poecllopoila 299 XX. Pojcilopoda 303 XXI. Poscilopoda :m XXII. Pcncilopoda 311 XXIII. PcBcilopoda 315 XXIV. Pfficilopoda 319 XXV. PoBcilopoda 323 XXVI. PoBoilopoda 327 XXVII. Pojcilopoda 331 XXVIII. PcBcilopoda 335 XXIX. PtBcilopoda 339 XXX. Pfficilopoda 343 XXXI. PcBcilopoda 347 XXXII. Pteropoda 351 XXXIII. Pteropoda 355 Fig. 1. Section from Lalce Chaniplain eastward across the town of Georgia, Franklin County, Vermont Ifi 2. Ideal section of the strata resting against the east side of the Adiron- dack Mountains, at the close of the deposition of the sediment-s of the Utica shale formation 25 3. Section of the Cambrian rocks of Prospect Mountain, Eureka District, Nevada 31 4. Section of the Cambrian rocks of the Wasatch Mountains, south of Big Cottonwood CaDon, Utah 37 5. Section of the Cambrian rocks of the Qrand CaQon of the Colorado, Ari- zona ti. Ethmophyllum Minganensis (after Billings) 77 7. Ethmophyllum Minganensis (enlargement of surface) 77 8. Ethmophyllum Minganensis (spicule, enlarged to 50 diameters) 77 9. Obololla chromatica , 110 10, Obolella chromatica 110 (733) 7 :i\ i ih ft- •. LETTER OF TRANSMITTAL ' ) ■ . ; , ' I • . Department of the Interior, UN-i^. States Geologicat, Survey, Washington, 1). C, February 15, ISSfJ. Sir: Herewith I have the honor to transmit the secotul of my prelim- inary studies on the Cambrian Faunas of North America. The huger portion of the report was reatly for ])nl)li(;ation July 7, 1885, but, havin;^ visited a number of localities in Utah and Nevada during the season of 1885, numerous additions have been made to both the text audthe plates. Very respectfully, CHARLES D. WALCOTT. Hon. J. W. Powell, Director U. 8. Geological Survey. (736) • Ml* < r i I ^ 4 l» K< THE CAMBRIAN FAUNAS OF NORTH AMERICA. By Charles D. Walcott. INTRODUCTORY OBSERVATIONS. jl I § 1. In using the name Cambrian in this paper for the series of strata characterized by the First or Primordial fauna of Barrande, I do not forget the claims of the name "Upper Taconic," which Dr. E. Emmons proposed for the strata now placed under the Middle Cambrian or Georgia Formation. At the end of these introductory observations the reader will find some remarks upon this subject which define my position at the present time. § 2. The term Cambrian is used from the belief that in so doing I approve of the view of those writers that hold that each of the distin- guished authors, respectively, of the names Silurian and Cambrian will be fairly recognized, and geologic nomenclature advanced by the use of the names Cambrian and Silurian for the divisions of strata char- acterized by the first and third faunas as defined by Barrande. This is spoken of here as, in the second edition of Geikie's Manual of Geology, 1885, p. 651, the author has included the Cambrian as a subdivision of the Silurian system. I do not wish at this place to question the wis- dom of this; but of the presence of a well defined geologic system beneath the strata characterized by the second fauna of Barrande or the Trenton fauna (including the Chazy and most of the Calciferous) of North America, on the North American continent, there is no question. The geologic sections given in this paper show it to have 11 total thickness of over 18,000 feoi,, and that its middle division has a known fauna of 43 genera, represented by 107 species. We also know that the Lower Cambrian or I'aradoxides fauna has 32 genera and 76 species ; that the Upper Cambrian or Potsdam fauna includes 52 genera and 212 species; that of the 393 species now 'known from Cambrian rocks but very few pass up into the Calciferous horizon of tlie Lower Silurian (Ordovician) ; and that the faunas of the two sys- tems are so distinct in thei; general facies, and also in detail, that they arc quite as re.idily separated as the Silurian and the Devonian or the Devonian and the Carboniferous. There is no doubt that in certain (737) U l'f-'if:(i r¥' t* ' , 12 CAMBRIAN FAUNAS OF NORTH AMERICA. (BULL.30. areas tbe faunas of the Cambrian and the Lower Silurian (Ordovician) systems are intermingled; but the same is more or less true of all tbo great div isions of tbe entire geologic series from above the great Arcbean break to the Quaternary. § 3. A good illustration of the mixing of the Upper Cambrian and the Lower Silurian (Ordovician) faunas is shown in tbe Eureka section of Nevada, in the fauna described by M. Barrande from the environs of Hof, in Bavaria, and still better in the Tremadoc of Great Britain ; but all this mixing, at tbe boundary line, does not prevent tbe recognition of tbe first and second faunas, as such, either above or below the ho rizon where the great change in the faunas took place. REVIEW OF THE STRATA AND FAUNAS REFERRED TO THE MIDDLE CAMBRIAN ORGEORGIA HORIZON. §4, I have long been of tbe opinion that the paleontologist should become personally acquainted with the strata containing tbe faunas be is to study, and, as far as it is practicable, collect the fossils or superin- tend their collection in order to learn their exact stratigrapbic relations to the geologic section and their relative position to each other in tbe section ; but, in the study of the enormous thickness of strata in tbe Rocky Mountain Paleozoic, it has often been impracticable to carry out the work in tbe degree of detail that is desirable. I have, however, studied in the field most of the sections mentioned in this article, and know from which horizons tbe collections were obtained, and therefore with considerable confidence express conclusions that differ from those reached by geologists and paleontologists who have arrived at their re-, suits through the accounts of the observations and collections of others or from stratigrapbic or paleontologic data considered without giving due weight to tbe importance of combining them. §5. While not desiring, at this time, to enter into a general discussion of tbe stratigraphy and paleontology of tbe Cambrian System as u whole, it appears desirable to present sufficient evidence to show that the Potsdam and Georgia horizons are well-defined stratigrapbic divi- sions and distinguished by large and distinct faunas in tbe same geo- graphic area and geologic sections. § 6. Tbe stratigraphy of tbe Cambrian System of North America has not been well known up to a comparatively recent date, and tbe extent and the character of its organic record are not yet appreciated. Dana's Manual of Geology, edition of 1881, p. 163, places the Cambrian as a subdivision of the Lower Silurian, as follows : I. Primordial or Cambrian Period. (2) 1. Acadian Epoch (2a). Sbule and saudHtone at St. John, New Bmnswick, the St. John gronp of Matthew and Logan, the Acadian gronp of Daw- son; beds at St. John's and elsowliere, in Newfoundland; clay-slate and silicious slate of Braintreo, Mass.; Ococo conglomerate and slates of East Tennessee and North Carolina. (738) WALCOW §10. WAUxnt.J INTRODUCTORY OBSERVATIONS. IS I. PritGordial or Cambrian Period — Continued. 2. Potsdam Epoch {2b). SandHtone of Potsdam and other places in Northern and Northeastern New York, Western Vermont, and Canada ; sandstone and limestone of Troy, N. Y.; slate and limestone of Northwestern Vermont, including the Oeorgia shales; limestone and sandstone of shores of the Straits of Belle Isle; Chilhowee sandstone of East Tennessee ; sandstone with some limestone in Wisconsin and Minnesota. § 7. On paleontologic evidence, Prof. R. P. Whitfield (Bull. Amer. Mu8. Nat. Hist., vol. 1, p. 140, 1885) correlates all the Cambrian faunas, practically ignoring the stratigraphic evidence then published. He says : My own impression, at the present time, is that the New York typical Potsdam is about equivalent to the lower portion of the Wisconsin areas, and that the Acadian beds of Canada and Vermont, and perhaps the other Atlantic areas, are not appreci- ably different in age, but that the difference in faunae is more the result of conditions upon which life depended than a difference in time. § 8. Dr. T. Sterry Hunt has been a strong supporter of the view that the Cambrian System exists in North America as a system distinct from the Lower Silurian (Ordovician), and advocates the use of the name Ordovician of Lapworth in place of Lower Silurian and the retention of the term Cambrian for the strata of the first fauna. He placed the Upper Taconic of Emmons in the Cambrian and gave a table showing the nomenclature and classification of North American rocks (Can. Bee. Sci., vol. i, p. 81, 1884). § I). The accompanying observations on the geologic sections of a portion of the Cambrian System and their contained faunas are also given that the. student may know the data upon which the writer pro- l)Osed dividing the Cambrian system of North America into subdivis- ions in 1883 (Cambrian Syst. U. S. and Canada; Bull. Phil. Soc. Wash- ington, vol. vi, p. 98, 1883). We will begin with an examination of the Western Vermont sections of the borders of Lake Champlain, where the Georgia Formation first yielded a portion of its characteristic fauna. WW*,' m I GEOEGIA FORMATION. § 10. The history of the Georgia Formation as we find it in the Geol- ogy of Vermont, vol. i, pp. 357-8, 374, 18(J1, is as follows : I'riinUive Argillaceotu Slate : Prof. Chester Dewey's Geological map of Berkshire, Mass.; Columbia and Kensselaer Coantioa, New York ; American Journal of Science and Aits, 1st sor., vol. viii, 1824. I'rimitive ArgiUaeeous Slate: Geological Report of Massachusetts, 1832. Black Slate and Taconic Slate: Roofing slate of tiio upper part of the Taconic System ; Prof. B.Em- nionH's works on the Taconic System, 1840-1860. Jludsan River Group or Lorraine Shaleg : Geological roni> of Now York, 1842 ; also in the Paleontology of Now York, vol. i, hy Prof. James Hall, 1847. "Roofing Slate of the laconic Syitem" but confidered at of the Hudson Kioer Group; Ri'_>r,rt8 on the Otology of Vermont, 1845-1847, by Prof. C. B. Adams. Ui>])er part of the Hudtoji Jtiver Group, or a distinct group above the Hudson River Group: Quoted by I'rof. James Hall, from tlie opinions of Sir William E. Logan ; Twelfth Annual Report of the Re- Ktnts of tho University of tlie State of New York, 1859. I'pper Hudson River Group: Elementary Oeology, thirty-flrat editiou, p. 411; by Bdward Hitohoook and C. U. Uitohcook, 1880. (739) I ' . PI li I. Brecciated limestone. 6. Conglomerate, composed of pebbles of limestone. The Georgia slate includes Avhat Professor Emmons has ranked as the black slate, Taconic slate, and roofing slate; and yet not altogether, for we have iregarded all the black slate beneath the red sandrock as belonging to the Hudson River Group. The characteristic trilobites of the Georgia slate are represented by Emmons in his Ta- coNtc •S'(/8tem, 1844, as found in the black slate. ' j. There are three views respecting the age of the Georgia slate : (1) Professor Emmons says it is the uppermost member of the Taconic System .uid that the Taconic System is stratigraphically below the Potsdam sandstone — that is to say, that the Taconic System is Cambrian. Upon pages 90, 91, of Part V of Amer- ican Geology, the Taconic System is directly compared with the Skiddaw slates «f Cumberland. In opposition to this view, we would say that the Georgia shit o rt'sts conformably upon the Red Sandrock series, as is shown in Fig. iir)7, and its fossils r.iiik it as Lower Silurian rather than Cambrian. (2) M. Barrande and Sir W. E. Logan, judging from paleontological evidonco, n^- gard the Georgia slate as equivalent to the Primordial Zone C of Bohemia, or very nearly the Potsdam sandstone of North America. » * • (3) The stratigraphical view of the Georgia slate, which has lieeu so ably defendcil by Professor Hall, seems to demand for it a place either above or equivalent to tlio Oneida conglomerate. § II. As we now know the Georgia Formation, it appears that Dr. Em mous was correct in placing it below the rotsdani sandstone, as was also done by Mr. Billings and later writers. § 13. The typical Georgia Formation, as developed in the town of Geor- gia, Franklin County, Vermont, consists, as seen at the base, of a great (740) WALCOTT.] INTRODUCTORY OBSERVATIONS. 15 thickness of magnesian limestones that pass, in their upper portions, into an arenaceous magnesian limestone that is overlaid by a belt of areuaceo-argillaceous shales, and this by a great thickness of a purer argillaceous shale that, high up, carries a brecciated limestone con- glomerate and lenticular masses of sandstone and limestone, from the size of a bean to masses 2,000 feet in thickness and several miles in superficial area. § 13. A carefully measured section (fig. 1, page 16), beginning at the base of the westward-facing clitt' overlooking the level that reaches to the shore of Lake Champlain, and extending southeastward through Parker's quarry, and a little south of Georgia post office, gives the following : Feot 1. Massive-bedded, bluish-gray dolomitic limestone with many inosculating • threads and bunches of a yellowish-drab sandy limestone that weathers in relief Uo 2. No. 1 ])asHes into a steel-gray dolomitic limestone that weathers to a dark , buff and bluish black, with angular fragments of bluish-gray limestone appearing irregularly at the surface. At 160 feet from the base the first band of mottled limestone, "Calico" or Winooski marble, is met with. The latter grades into a reddish dolomite free from mottling, and then in a gray limestone. (Fossils: Hyolithellust) 200 3. Gray dolomitic limestone in massive layers, some of which are mottled, red- dish and white, but the larger part are gray and yellow. Many of the gray layers break up into a columnar structure, the columns being at right angles to the bedding. In a reddish-colored limestone, 200 feet from the base, a slender elongate tube occurs, probably HyolUhellus micana 475 4. Reddish-pink dolomitic limestone weathering to a reddish brown and de- composing, on the exposed edges, to an arenaceous, dark, brownish-red rock that shows numerous fragments of fossils : Kutorgina Labradorica, Oholella{f) sp., Salterella pulchella{i), Ptyohoparia Adamsi, OlcneUus Thompsoni 100 5. Gray arenaceous limnsrone in rough massive layers, passing into more evenly bedded light-gray arenaceous limestone. Fossils similar to those in 4 occur in the lower portion 190 Total thickness of limestone 1,000 6. Georgia nhahs. — Argillaceo-micaceous and arenaceous shales containing niunerous fossils at Parkf ' "'dge and showing deposition contact on No; 5. 200 Strike at Parker's qtiarry N. :{0° E., dip 8^ to 12« E. Tilt; fos.siliferons shales at Parker's quarry contain : ralwophyciis iucipiens, I', roiigrcgatua, DipJograptua (.') simplex, CHmacograptuH (?) Emmonsi, Kutor- ghia ciiigiilata, Ortliinina Orientalis, O. festinata, <). trnitsverm, O. sp. (f), MicrodiKCiia Parkcri, Mesonucia Vermontana, Olciiclhia Thompsoni, Olenoidea Marcoui, ISathynotua holopyga, I'tychopavia Adamii, /'. I'lilcanus, I'rotypus nUchcocki, P. sriirciiis, and /'. scnectiis var. parrulus. 7. Hast ol'tho Parker quarry the rocks are argillaceous shales with occasional layers of hard gray limestone, one-half of an inch to two inches thick, that carry nunicrous fraguieiits of a linguloid shell 3, fjOO Strike of shales near top of 7 N. 40° to 60° E., dip 60° S. E. . 8. I.iglit-gray quartzite 50 (741) ill- '«•■'' m i . ♦!«} • ' Si*^ rf 'ii If ;«i'i!C -ji m m m 1 i f '•' ' ' j •1 ,111 i :■ : i lull -." ; > if i J If ■. *• 16 CAMBRIAN FAUNAS OP NORtH AMERICA. I a « 3 9 o (742) •a a eg p. •c 2 5 ■is *^ s i ..t .H ^ « o .a ■a « l3" _ § i o ■^ B 5 ,2 2^ 3 p..g 4) .3 o Hi o 1-4 p ^ IS fmn.i.. so. liaviiig disi WALCOTT.J INTRODUCTORY OBSERVATIONS. 17 Feet. U. Gray liiiieNtono in innHsive layora, with ucc^aHionsl intercaliiMMl biiixlH of Iianl ur^illaceouH shale siiiiilur to that beucath t\w liiiioAtoiio. Many of tho beds of limoHtoDb appear to have been broken np into fra^nieutH and rece- uientedin situ 1,700 Average strike of limestone beds N.50° E., dip SO" to 1)0°, avorngo dip 60OS. E. In this limestone bolt, one mile north of where the section crossed, a few fossils were found: Lingula, n. sp., Orthisina uudt. (fragment), Caniarella undt. (probably new), Agnostus like A. Orion, and Ptycho- paria like P. Adamsi. 10. Argillaceous shales, very similar to those in the Parker ledge, continue on up to the opposite side of the line of tlio Vermont Central Railroad track. At the base the shales rest conforniouly against the lihiestone of 9, and above appear to be cut oft' by a fault. Strike N. 50° E., dip 60° to 80° S. E, for a distance beyond the limestone; the dip then decreases and does not exceed 20° for a long distance, until within 1,000 feet of the railroad rack, where the shales become coarser ami changed by addition of arenaceous material and the dip increases. Total thickness to fault line of No. 10, :?, 500 to 4, 500 feet. § 14. No. 8 of the section when traced on its strike to the south- west increases in force very rapidly to tlie thickness of 500 feet or more, and also changes from a quartzite to a more or less calcareous sand- stone, containing irregular fragments of argilhiceous shale. Follow id to the northeast, it soon disappears and the. limestones rest directly on the shales. Continuing northeast on the limestone (9), it is ibund to decrease rapidly, and a mile northeast or where it is over 1,500 feet in thickness the width across the outcrop is not over 150 feet, and soon the shales above it and those below it come together, the limestone having disappeared. Southwest ot the line of the section the width of the outcrop narrows, and north of Georgia IMains post office the entire section is covered by beds of sand. No. 9 appears to be a great lenticular nniss of limestone (lentile of Marcou), with intercalated beds of argillaceous shale, and more rarely with arenaceous beds imbedded in the argillaceous shales. The fauna is (/umbrian in character, and, in the absence of Olenellus and other typitial Middle Cambrian fossils, approaches that of the Upper Cam- brian or Potsdam sandstone. § 15. On Mr. Noah Parker's farm a lenticular mass of calcareo-arena- ceous rock is exposed on the edge of the first clitF facing west, where trilobites are found: Olenellus, Bathynotus, &e. (G of the section). The mass is small : 25 feet in thickness at the center and about 50 feet in diameter, as seen in the section. Erosion has removed most of the shale from above it, but in a second lenticular mass, just back of it, the shales may be seen resting over and against the upper side of the cal- careo-arenaceous rock, and in the shales numerous small masses of a similar rock occnr that are not over s.x inches in diameter. On the hill, still forther to the nortlieast, a hard cilciferous sandrock occurs that appears to hf^ a rcsmnant of a diflferent formation from the shales Bull.30 2 (743) 1 >■•■■» x'-ff It'! J if rstJ Iff ■ill mi m b' ■*?'■' f'" 1 V : , it: ■ ■ . Iti';':'.;;: 'a li'' ■' ' ' 18 CAMBRIAN FAUNAS OP NORTH AMERICA. [bull 3a below ; but a close study shows it to be a portion of a lenticular oiatM left by erosion, and resting conformably on the shales beneath, each dipping 1(P eastward. Several other instances were observed where erosion had left these masses resting on the shales; and it was not until they were fouud to pass beneath the shales, to have imrlious of tiie shale still preserved on their upper surface, and to contain the same species of fossils as the shale, that the writer felt sure that they were not fragments of the later formation deposited on the Cambrian beueath. It is these masses that Prof. Jules Marcou referred to the Potsdam sand stone (Bull. Soc. G^ol. de France, 3" ser., t. ix, p. 24, 1880). In a letter to the write'', dateil December 20, 1885, Prof. Marcou states that the sandrock at Parker's quarry was referred, by error, to the "Red Sand- rock or Potsdam Sandstone," as his Held notes of 1801 place it in the Georgia series as a " lentile." § 10. A section taken east of Highgate Springs, beginning on the line of the same fault as the Georgia section, gave a slightly greater tliick- uess and also more arenaceous matter in the limestone series beneath the Georgia shales. The section begins on the east side of the road running from St. Ar- mand, Canada, to Swanton, Yt., near the house of Eldad Stearns: Feet 1. Compact gray silicioiiH liiiiestone ill massive layers 20 2. Gray oalciforous limestoiK'. compact, bard, evenly bedded, breaking up into sbaly layers in places, ^oiue of the layers decompose on exposure into a reddisb saudy rock 180 3. Compact piirplisli, piukisb, or greenish colored silicious limestone in mas- sive layers 30 4. Thick layers of buff and pi nkisb-colored silicious limestone with fragments of Plijehoparia Adamsi 15 5. Heavy-bedded, reddish-purple, fine-grained magnesian limestone, breaking into angular I'la^mcutH {I'tycho2)aria Adainni in nbuiiduiice) CO Strike N. 30° E., dip 25° to 28° E. 6. Shaly and massive layers of g ly and purplish colored sandstones contain- ing fragments of Plychoi)aria Idamsi, occurring at various horizons 175 7. Reddish-colored arenaceous limestone, with irregularly bedded massive lay- ers of gray silicious limestone and a few more-ovenly-bedded layers carry- ing fossils: Eutorgina Lahradorica, Orthinna ftel'mata, Orthisina ap.t, Sce- nella varian8, Hyolithesfip.l, Salterellapulcluillaf, Olenellue Thompsoni, Ptycho- paria Adamai, Ptychoparia Teiicer. Layers of gray and buff sandstone also occur at intervals 700 Total 1,170 8. Georgia shales. — Argillaceons shale with interbedded masses of limestone, layers of sandstone, and silicious limestone. In the limestone, Eutorgina oingulata, Orthisina festinata, Olenellus Thompsoni, and Ptychoparia Adamsi occur 1,000 9. Heavy layers of silicious limestone, with layers of sandstone midway, ex- ^. tending about 100 feet 850 Average dip, 20"^ ; distance, 2,500 feet. A fault line here cuts off the section. § 17. The section east of Swanton does not show as great a thickness of the limestone beueath the Georgia shales, and a fault line crossing (744) muxm.] INTRODUCTORY OBSERVATIONS. 19 Fc«t 20 160 30 15 60 176 700 1,170 .. 1,000 850 section. the shales a littlo obliquely to the strike cuts out a portion of them. On the east side of the fault two or three hundred feet of shales occur, and then a layer of conglomerate limestone, the fragments of limestone varying in size from pebbles to masses six feet in diameter. The fossils in the limestone conglomerate have an Upper Cambrian aspect and incUule Lingula sp. ?, Amphion ? sp. f, Bathijurua sp. ?, a fauiiii tiiut may be compared to that obtained in itonw of the bowlders of the Point Levis conglomerate. Below the horizon of the conglomerate and in situ in tbe shales we found Lingulella^ Agnostun, IHychoparia, and Solenopleura. With the exception of the Solenopleura the species appear to be iden- tical with those in the limestone "lentilo" (9) of the Georgia section. § 18. A section taken east of Swanton by Sir William Logan (Geol. Canada, 1863, pp. 281, 282) gave 520 feet of the limestone series; by tracing the strata north nearly to the Canadian boundary, he found 1,410 feet in the section ; another series north of the Province line gave 790 feet, making a total of 2,200 feet, part of which is estimated. That this portion of the Georgia Formation thickens rapidly to the north there is little doubt; but, until further study is given to the cor- relation of the horizons in the different sections, I should hesitate in giving it a greater thickness than 1,500 feet within the limits of Ver- mont. § 19. The fauna of the Olenellus horizon east of Swanton gives A'm- torgina eingulata, K. Labradorica, Orthisina Onentalin, O.fetitinata, Ca- marella antiquata, Salterella pulcJiella ?, Olenellus Thompsoni, Ptychoparia AAnmai^ and Protypus senectus. § 20. The Georgia section is the most complete yet taken in Vermont. At the base the great belt of dolomitic limestone, 1,000 feet in thickness, rests against and, by a fault, overlaps the Trenton limestones of the Ordovician (Lower Silurian). What was originally beneath the lime- stone belt is yet undetermined.' In the Highgate section the limestone belt is nearly 1,200 feet thick. The base is unknown, and it does not appear, so far as I know, in the section between the boundary of the United States and Canada and the outcrops in the town of Georgia; Following the Georgia section up, a great mass of argillaceous shales, 3,500 feet in thickness, occurs before the great "lentile" is reacheii.3o § 29. The sectiou, jih detormincd north ninl west of Bnrntogii Spi iiijfH and north as fur oh Corinth, Nuw York, huM, at the baNO, about L'OO Ihi of evenly-bedded, compact, grayish to yellowiHli colored HandHtoiie, tlni* restti unconformably against or upon H\mrn or ridges of Archean ^'iieisN. Including the upper beds of sandstone, the section throe miles noitli nt Saratoga village gives in ascending order: Keet. 1. Samlatone 40 2. Oulitio limestone 'M l\. Dark-gray, evenly-bedded lininHtonfl 50 4. Unfoasiliferous, impure, compact, more or lew* silicioiiH limo8tone % r>. MaHsive- bedded, Hlightly magueHiau, gray and dove colored limeHtoues with numerous small, narrow-cbanibered cepliulopods near tbe snmuiit 'X> 6. Macsive layers of steel-gray, more or less arenaceous limestone 125 7. Bird's-eye limestone li 8. Black River limestone 4 9. Trenton limestone 40-f §30. The passage from the Potsdam fossil bearing limestone (3) of tlie section to the dove-colored limestones (5) carrying the cephalopcxls is through a considerable thickness of more or less impure, sligiitly avtMin ceous limestone that has been known as the Calciferous sandrock iii this region, but at Rock City Falls the Bird's-eye limestone rests di rectly on similar beds, and from a study of the strata to the uortliciLst, in the vicinity of Glens Falls, I am inclined to think that it is impos sible to recognize, by lithologic characters, the Calciferous formation as distinct from the Chazy limestone horizon ; and at Glens Falls Machim magna and great numbers of an Ophiiita like 0. compacta are found in the same stratum of rock but a little distance beneath the Trenton lime stone, an occurrence that renders it very difficult to state what is to be assigned to the Calciferous horizon in this region and also in the valley of Lake Champlain, as our section at Chazy, N. Y., gave 700 i'cet of limestone with Chazy fossils to the base, where the limestone rested on the sandy, fucoidal layers just above the Potsdam sandstone. These fucoidal layers have been referred to the Calciferous on but very slijjlit evidence.* § 31. The limestone (2,3) capping the sandstone (1) of the section is also found at Whitehall and at Comstock's Lauding, Washington County, New York, where it has been, as was the limestone (2, 3), referred to the Calciferous. The limestone 2 and 3 appears to have been, on tlie southwestern side of the Adirondack Mountains, the closing deposit ol the Cambrian ; and there is but little doubt 1 hat if we could tind ii fauna in the limestone (4) of the section it would serve to connect the Cambrian and Lower Silurian (Ordovician) faunas. ' This nonconformity by non-deposition, noticed by Logan, is nowhere better illus- trated than in this section ; the entire Calciferous or Phillipsburg ibrmation, so near at hand, is absent. The same irregularity of deposits, indicating varying levels iu the sea bed, is noticeable around the Adiroudavks to the southern side. (748) \s f fAUrOTT.) INTRODOCTOKY OBShKVATlONS. 93 §32. The beds 2, 3, 4 till in, to a curtuin de^cc, tliu gu\y M'hidi oxiNtM iM'tweoii the PotHdiviu aud theChazy, in the (Jhazy Hectiun. In tho Mo- Imwk Valley, at Little Falls and at Fort IMaiii, the Chazy formation i.s ubsuiit, a considerable development of tli<^ Caluifi>roiis, 'MM feet or more, rtlliiig in the space between the Archean and the Trenton (Hinl'M-eye liint'Htone) ; the Potsdam and older Cambrian formations being absent except at the " Little Nose," on the New York, West Shore and Buf- falo Railroad, Montgomery County, New York, where a band of decom- posed gneiss aud lenticalar masses of shale, that occuis between the ({neisH and Calciferous sandrock, is referred to the Potsdam horizon. (Prof. James Hall.) § 33. In the February number of the American Journal of Science (.{d ser., vol. xxxi, pp. 125-133), Prof. W. B. Dwight des(!ribes a belt of lime- stone near Poughkeepsie, New York, containing fossils of the Potsdam fauna that, from the references made to them, appear to be identical with the fauna of the Saratoga Potsdam limestone, even to an identity of species. The limestone is described as over 300 feet in thickness, and 12 or more species of fossils have been recognized. This discovery is of great interest and importance, as it shows the ))resence of the i'otsdam fauna of the Adirondack region 100 miles farther south and in the line of a series of sediments that, 50 miles north, curry the fauna of the Middle Cambrian. The inferenct^ is plain that we may expect to find the two faunas in the Sii ue section, somewhere along the line of the Upper Taconic of Emmons. § 34. From what has already been given, it is evident that the Pots- dam formation has not been observed by the writer in Northern Ver- mont as it exists in New York, but the inference is that the upper mem- bers ot the Georgia section, or those carrying the lenticular and brec- ciated masses of limestone, are near the Potsdam horizon, or, as Sir William Logan said, in speaking of the equivalents of the Potsdam (Geol. Canada, 1803, p. 235), " out in deep water the deposit may have been a black, partially calcareous mud, such as would give rise to the shales and limestones which come from beneath the (Quebec group." This view is illustrated by the ideal diagrammatic section, fig. 2, page 25. § 35. Accepting the conclusion that the matrix of the. conglomerates at Point Levis is of Calciferous age, whicl was Sir William Logan's view, as expressed on page 233 of the Geology of Canada, the above view of the origin of the Georgia shales and the included cahiareous beds, and their equivalency to the Potsdam Sandstone, is, to a certain extent, cor- rect; the error consisted in considering the entire deposit as equivalent to the Potsdam, whereas it appears from the faunas that the limestone series of the Georgia Formation, including the " Wiuooski marble" and "Red sandrock," was a deposit antedating the Potsdam Sandstone of the New York series ; that a considerable portion of the Georgia shales also antedated the latter, and that strata of an age equivalent to the Pots- dam Sandstone were deposited in a continuous series, and conformably (749) .«.. m i » 5 I ill Hi ;h 24 CAMBRIAN FAUNAS OP NORTH AMERICA. IBUU. M. '■■A'- '< on the deposits beneath. Such appears to be the deduction from tJje Georgia, Swanton, and Highgate sections when compared with those of the Potsdam about the eastern and southeastern base of the Adirondack Mountains. §36. The view expressed by the section, fig. 2, page 23, is that there was a practically conformable deposition of sediments, against and over the Archean area of the Adirondack Mouutains. from early Cambrian times up to the close of the deposition of the sediment forming the Utica shale, except in the case of the unconformity by non-deposition between the Potsdam and the Chazy. The writer has seen the deposition contact of tlie Utlca shale, against the granite, on the eastern side of the Adiron- dack Mountains, in Essex County, New York, and takes that as the up- per line of the ideal section, although lie has little doubt that the forma tioiis overlying the Utica shale, even through the Silurian, were depos- ited against and over the Archean of the Adirondacks and subsetiuently removed by denudation. Numerous minor iaults now bring the strata of the ideal section in various relations to one another, e. g., the Potsdam sandstone resting against the Cha/y and the Trenton, as at Cliazy, N. Y.; the limestone of the Middle Cambrian of the Georgia section thrust over on the Trenton series, &c. §37. In Fig. 2, the Potsdam formation, near the Adirondacks, is rep resented as a sandstone ; to the eastward, as an arenaceous argillaceous shale; and beyond, as an argillaceous slate with irregular masses of lime- stone (lentiles) and thin beds of limestone intercalated in the slate or shales. This succession shows shore, offshore, and deeper water de- posits. The Trenton, Ohazy, an«l Georgia limestones are represented as deposited directly against the Archean. We know this was the case witli the Utica shale, and it appears to point to the submergence of the Adi- rondacks in the vicinity of the contact observed in Essex County, so as to prevent the disintegration and deposition of the materials composing the Archean, the mud, forming the Utica shale, being deposited against the ledges of granite that were entirely below atmospheric or wave ac- tion. ST. LAWRENCE VALLEY. § 38. The conglomerate limestones of Bic Harbor, St. Simon, and up ihe St. Lawrence to the island of Orleans, and thence southwest toward Lake Champlain, do not appear to have been derived from pre-existing strata where they were deposited, as appears to be the case with tlie brecciated limestone in the vicinity of Troy, N. Y., but to have bcon transported and deposited as a portion of formation of a later geoli)}>i( age. Dr. Selwyn has shown this to be the case with the Point Levis beds which contain bowlccrs, some of which carry Georgia fossils, others Potsdam fossils, and others Calciferous fossils, the last being uoarl\ contemporaneous with the matrix of the conglomerate, the noted grap tolitebeariug shales. (760) WAI.COTT.] IKTRODUCTORY OBSERVATIONS. 25 pa 0) wave ac- 'Q. * i S O B on (r ft © 3 3- 5'i: w S" o ^ 5 » 3 tt B: I 9 I ■a I B S" -I S 0 ^ !' »> ». 3 01 & I s-'l- a 9 9 1 i g D o 2_ 1 ? s. o 3- o 1 g §• 3 a § ■^ g g ?« O f? ^ n> h* 6^ g fD rs ff P »-»> r» «I ^ ff f E 1 1' ^ f 1 1 ? ^ s 1 e- f 1 I } '■,■^'4 M (751) Hiiii .(£? i< . J,jr * ■ ^6 CAMbRiAK PAtNAS OP NOftTtt AMEftlCA. [BUtL. 3d. § 39. Sir William Logan, in describing the section at Trois Pistoles, says : ''At Trois Pistoles, in a section of 700 feet of strata, 150 feet at the base consist of gray calcareous sandstones and coarse liinestoue conglomerates, the latter comprising one-third of the amount, in nine separate layers of from two to sixteen feet thick. The matrix of the con- glomerates is a gray calcareous sandstone; and the rounded masses im- bedded in it, in addition to limestone, Qonsist of quartz, and occasionally of amygdaloidal diorxte. Of the limestone and the diorite, there are masses weighing from a pound to a ton, while the quartz pebbles seldom exceed an ounce." (Geol. Canada, 1803, p. 260.) This mode of occur- rence compels us to refer to the faunas as from strata of which we have, as yet, no positive information. § 40. From Bic Harbor, Trois Pistoles, and St. Simon the following species have been found in the conglomerate limestone, as observed in the collection of the Canadian Geological Survey : Lingalella cslata. Iphidea bella. Kntorgina ciugulata. Obolella crassa. Obolella Circe. Obolella gemma. Orthis 2 n. sp. Platyceras primsBVum. Hcenella retusa. Stenotheca rngosa. HyoUthes Americanua. Hyolithes communis. Hyolithes princeps. Hyolithellus micans. AgnoBtao sp. T. Microdiscus lobatus. MicrodiBciis Hpecioeus. Olenellus Tbompsoni. Olenoidcs Marcoui. Olenoides levis. Ptycboparia Adamsi. Ptycboparia Teucer. Ptycboparia f triliueata. Ptycboparia sp. undt. Ptycboparia (Agraulos) strenaas. Protypus sonectus. Protypus senectus var. parvalua. §41. On the island of Orleans, Dr. Selwyn found in the conglomerate limestone: Obolella crassa. Ortbisina sp. f . C'amerella sp. T. Hyolitbes Aiuericanns. Hyolitbellus micaiis. Olenellus Tbompsoni. Ptycboparia Adaiusi. Ptycboparia Vulcanua. Solenopleura sp. t. Protypus senectus t. Olenoides Marcoui. Olenoides levis. § 42. At Point Levis, Dr. Selwyn also discovered a pebble of lime- stone, in the conglomerate beds, filled with beautifully preserved speci- mens of SalUrella pulchella. TROY, NEW YORK. §43. Passing to the locality which Mr. S. W. Ford has made so well known by his researches, we find that the conglomerate limestone is of the same geologic age as the limestones with which it is interbeddod in the argillaceous shales, as both carry the same fauna ; and the conglom- (752) WALCOtt.] I^JTP.ODUCTORY OBSERVATIONS. 2t erate is brecciated, although showing evidences of wear in most in- Btances. The limestone appears to have been consolidated and then subjected to wave action. In some instances great masses of the evenly-bedded layers remain intact, while a little distance away they are broken up and buried in arenaceous and argillaceous sediments. §44. The section as described by Mr. Ford (Amer. Jour. Sci., 3d ser., vol. ii, p. 33) consists, "for the most part, of coarse red and yellow weathering slates and shales, with occasional thin-bedded sandstones; but most of them are supposed, and four of them are known, to hold subordinate limestone deposits. Of these deposits the two westernmost individually consist of a few courses of thick-bedded limestone, and of irregular, sometimes lenticular, sparry and frequently pebbly masses, varying from one pound to several hundred pounds in weight, imbedded iu a coarse, dirty-looking arenaceous matrix; while the others form tol- erably compact even-bedded limestones, with an abundance of scattered black nodules, from 25 to 30 feet in thickness. The same species of fossils, with a few exceptions, have been found in both the even-bedded and conglomerate limestones." § 45. The following list is made from the species in Mr. Ford's collec- tions and those of the Dnited States Geological Survey : l4 f lie m Ethmophyllum raram. Ethmophyllom Rensselaericnm. Lingulella cselata. Obolella orassa. Obolella gemma. Obolella nitida. Orthis sp. T. Fordilla Troyensis. Scenellaretasa. Stenotheca ragosa. Platyceras primeevnm. HyolitheH Americanus. Hyolithes cummunia. Hyolithes communis var. Emmonsi. Hyolithes impar. Hyolithes sp. T. Hyolithellus micans. Leperditia Troyensis. Agnostus Dobilis. Microdiscus speciosus. Microdiscus Meeki. Microdiscus lobatus. Oleuellus asaphoides. Ptychoparia trilineata. Soleuopleura Nana. § 46. South of Schodack Landing, in Columbia County, New York, Mr. Ford obtained a better section than at Troy (Amer. Jour. Sci., 3d aer., vol. xxviii, p. 36). The base is cut ott" by a funlt and the upper limits are unknown. It shows the varied character of the strata and the position of the brecciated limestone (in 7 of section), carrying twelve species of fossils identical with those at Troy, viz : :%'m ^SJItil p '-M I icellocephalu8, or even CrepicephulitH, as we have specimens of the latter from the Potsdam of Alabama 20 ceutiu' iters in length, in- cluding terminal spines of the pygidium. The brachiopod from the Cat- linite quarry, described as Lingula calumeU looks very much like an Obolella. It is therefore evident that the fossils of the Oatlinite beds do not fix the geologic horizon so that we can correlate them, although the section is much like that of the Grand Canon of the Colorado, and the Catlinite beds are probably Pre-Cambrian. Geographically, we should speak of the Wasatch section first, but, as the section and fauna are more thoroughly known in Kevada, that area will now be considered. X, •'■ mm \m: ■■•■ ■ If,.; . NEVADA. § 52. The Georgia horizon, in the Cambrian section of the Eureka mining district of Central Nevada, is shown in the accompanying sec- tion, taken from Mr. Arnold Hague's Report on theGeology of the Eureka District, p. 253 (Abstract in Ann. Rep. Director U. S. Geol. Survey, 1881-'82): [Cambrian, 7,700 l'<^et.] 5. 350 Yellow nrgiUaceous shale ; layers of chert notlnles throughout the bed, but more abundant near the top. 4. 1,200 Dark-gray and granular limestone; sur- face weathering, rough and ragged; only slight traces of bedding. • 8. 1,600 Tellow and gray argillaceous shales, pass- ing into shaly limestone near the top; intorstrntifled layers of shale and thinly bedded limestones. 2. Prospect Mountain limestone. . . 3,050 Gray compact limestone, lighter in color than the Hamburg limestone, traversed with thin seams of calcite; bedding planes very imperfect. 1. Prospect Mountain qnartzite . . . 1,500 Bedded brownish-white quartzites, weath- ering dark brown ; ferruginons near the base; intercalated thin layers of arena- ceous shales ; bods whiter near the sum- mit. 1 Total section 7,700 1 1 if-'1 iJ § 53. At the summit of 1 the quartzite becomes more thinly bedded and passes into an arenaceous shale which is more or less calcareous and, in its extension northward, is replaced by limestone. This belt of (756) [BULL. 30. WALfOTT.] INTRODUCTORY OBSERVATIONS. 81 p- ^ fcr* er 9 (5 C IJ;- C " » D 1 * I &i 2 O « e- c- =- <-^ t — . Bo? f* ^ « cr ^ -r. c » S ^ P r^ C ^ ^^ c- » O £ K* » B S g* B 2 B a ■ t a ■• 0 09 B s r « ** S" s 3 E H u T5 B d O r* a § B- a o a CO to a &• o B & B a o S B 2 " 5. E O (» o I a S. W 5* o 2. £, 2. » S: & J! " 2 B' a a B c CI c: : B B t *^ B a & If ~ o B^ IS" * SI. o s: CD B g B* p a, fB OD -• a e ^ B » >^ c B = a OB *-• * £ » o< " hd " 3 " O 2.0 B tt>. e . p __ "1 o g. a * E "• «* to B B i "^ B tJ g-r ^ 2 » B cr O -1 » ^ a- s c 3. p a P « o p D Q< B 9 ir I. S B O o o ft 9 C767) .in 1 i' ^'MfSSfi 1" t %imB Iflf ml ■ •*,'■!: " ■ ^ ■ ! i?^:i!' .. ■M ' ■ 82 CAMBRIAN FAUNAS OP NORTH AMERICA. [BULL. 30. shale and limestone \n from 100 to 200 feet in tbickness aud carries nu- merous fraf^mentH of fossils, among which we have determined six spe- cies, viz : Kutorgina ProspeetenHis, Scenelta conula, Olenoides quadriceps, OlenelluH Gilberti, 0. Iddingsi, Anomocareparvum,fi,rn\Ptych' \ ; ' 'l M: ■f "! !■ I i Mil 84 CAMUniAN FAUNAS OF NORTH AMERICA. tBUi.L.30. T'oHsils: OleiivUiiH Gilhfrll. Font. :?. Bull' jirgillaceouH mid nfienacooiiH sliiiles, more or Ichh solid n»!ur tho bane and lainiiiati'fl in tin- niiitcr i)<)rti(>ns 80 FoshUs: Amiiiiid trails aii(H'ra;i;riuint.s of Olenolliin iu tho lower part. Higher u|), tlio heads of OJenMm Gilhtrli aiiJ (5. Dark bluitsh-black limestone 4(i 7. Finely laminated bull' iU'^inacoous shale 80 Fossils: Jfjiolilhin JiiUhij/Hi tind I'tiicltojiaria riovlwntis. 8. Gray to bluish-blnck (tomjiaet limestone Ifl •J. liuirareuiici'ous shales 64 10. Ooniimet cherty liniestone I'lO 11. Compiiet shaly sandstoin! in massivaet gray silieious limestoue, almost quartzite in some jilaees 400 (c) Bluish-black, even! V bisdded limestoue 6 (i06 Strike N. .lOO W., dip HP E. 21. Buff to ])inkish arifiliaoious shale, with fossils, and a few interbedded layers of limestone from 15 t" !.'» iuelies tliick 125 Fossils: Jiocynlilcnf? hnujhlacljihifs, Linguldla Ella, Kiitorghia pannnla, ffi/oUllien lHUini/iii, riychoparia Fiocheiisin, OU'noich>ityi)Undi8, Bathy- nrixoiH Hou-vW, and II. [iroducla. 28. Massive-bedded, silieious limestone; weathering rongli and broken into great belts, iJOO to 300 feet thick, by bands of color iu light-gray, dark- lead to bluish-blaclc; ou somo of the clitf faces tho weathered surface is reddish 1,570 23. Bluish-black limestone iu massive strata, that break up into «haly layers on exposure to the weather, Th feet thick. § 70. On the west side of the Highland Range, wesi *" the highest l)oint, the upper (Eureka) quartzite is shown in a hill north of the ntad leading from Rennet's Springs to Hiko. Fossils are very abundant. No strata overlying the upper quartzite were observed in the Highland Range between Rennet's Springs and two miles Morth of Bristol; but in the Pahranagat Range, both Trenton and Silar San (Niagara) fossils occur within 500 feet above the quartzite. § 7^. West of the Highland Range, at Silxaf Peak, Nevada (long. 117°, 20' W., lat. 380 N.), Mr. J. E. Clayton collected a few fossils to which Prof. J. D. Whitney called the attention of the California Aciid- emy of Sciences, in 1860, referring to them as probably Upper Silurian or Devonian (Proc. Cal. Acad. Sci., vol. iii, p. 270, 1866). § 72. Mr. F. B. Meek subsequently studied the fossils, referring to them as Silurian, and describing Ethmopliyllum Whitneyi and E. gracilc (Amer. Jour. Sci., 2d ser., vol. xlv, p. 62, 1868) as corals, and then, in tlie same year, referring (ibid., vol. xlvi, p. 144) them to the genus Arclite- ocyathns of Billings. No other species were mentioned by Mr. Meek. § 73. The original collection from Silver Peak, or a portion of it, was found in the Suiithsonian Institution collections, and proved to be- <762) WALCOTT.) INTRODUCTOKY ODSEUVATIONS. 37 nan U'St (tiul ant. and but Dssils g; to racilc II tlie rclue- ek. was 0 be- o •J, u hq ^ O S a *• •t & ft. e 2, 2. ^ •? 3 H £ §"" 3 !; KH a c. ~ o -. B = ^ ft B a- S 3 £,•0 ft (t) S 5 B O » 2. 3 s- Is 1 13. il » >5 "I -. O o B B B B S g. O c a, C 3 Is- 3. o I I M II I o a 5 o '^ a -« SO =* s a ^ a u ■ • at t/1 o • -1 D » 3. £ I.- f 2 o a ! B a ■ ►- H « c; §3* (^ 5-3 ^* n a- B S b' i. 0 o fi 3 •a — •a p = "2 2. S o B O n n o a » CI o B n o "=1 o OJ B B -) O (763) • II 1^ , '". II) ■i,'S:- f^^^ ^r^ i-i li n^. !:!■ mm iili 38 CAMBRIAN FAUNAS OF NORTH AMERICA. [bull. 30. lonpf to the Middle Cambrian fanna which is so extensively developed iu Central Nevada. We have no description of the section, but the fossils are from a limestone and silico-arj^nllaceous shale, and identical with species fouud elsewhere. The most noteworthy occurrence is that of ArchoEocyathvs Atlanticus and a large brachiopod like Kutorgina cin- gulnta, both of v/hich occur over 3,000 miles to the east-northeast on the Labrador coast. The abundant and peculiar typ,^ ol" sponge Ethmophyl- Inm profundnm, of the L'Anse au Loup locality, is represented by the nearly identical species E. Whitneijl at Silver Peak, and the trilobite Olenvllus Gilberti is scarcely distinguishable from 0. Thompsoni as it oc(!urs at L'Anse au Loup. The species now known from Silver Peak are: Arcbtoocyathus Atlauticiis, Kutorgina (liko K. eingalata). ArdiiPocyiiMins iukU. sp. llyolithes princi4)H. Fithniophylluiu Whitneyi. Oleuclliis Gilherti. Strepbocbetus ? sp. ?. UTAH. §74. The writer visited P>ig Cottonwood Ciifioii, in the Wasatch Mountains, during the summer of 1885, and examined the great Cam- brian section described by the geoh)gists of the Fortieth I'arallel Sur- vey (Geol. Expl. Fortieth Par., vol. i, p. 2L'f); vol. ii, p. .'!06) more in detail than they haartings lictween the more massive bands of layers. In some places the ((uartzitic sandstone shows grains, and in otluM's fhey are lost. Stains of purplis iron-rust, reddish- brown, and hutf color occur 2,700 9. Black, sandy, arenaceous, slightly micaceous shal 'S 75 10. Gray, compact, (juartzitic sandstone 700 11. Purplish and reddish-brown quartzitic sand.stone 75 12. Gray, compact, (|uartzitic sandstone 3, 000 13. Hard, Hilico-argilhicoous shales, a little sandy in places iiSO Fossils : Cruxiana sp. ?, Lhi(/iilcHa Ella, Kutorfjina patniuhi, Jli/dUtluH Jtil- Ungvi, Lcperditia Argcnta, Olcnellus Gilbcrti, I'hjvJioparia qnudrmiH, aud Baihyvrhms prodncta. Total 12.000 § 75. A band of mixed sandy and calcarooibs rocks rests confornialViy on 13 of the section, and carries a fauna wiiich I'cfers it to the Lower Silurian (Ordovici^n). § 76. Tlie fauna! Jiorizon of the fauiui contained in the sliales of 13 is ill once kicated by a comparison with tho faunas of tlie TIis of 13 of th<^ ic"- tion is the locating; of a horizon by which we can comi)are the section. At Eureka, High land Hange, aiulTimpahutelbmge, Xevada, the quartz- ite of 12 te'-'Muated the section below, but now we have 11,750 feet of strata in a conformable series that extend down to the granite (prob- a])ly Archean). §78. The section iu the Oquirrh Eange, above Ophir City, shows a (705) 'Iff 9 ■iv I |.v'.; ■A- ■i^'^i ■> ' ' EJ I I •i 40 CAMblilAN FAUNAS OF NORTH AMERICA. [bulu3o. quartzitc with .shales ijbove it carryiug IjhujuleUa Ella, Olemllm Gil herti, and liutliyuriscus ]noducta, and at Antelope Spring, in the House liauge, Western tltah, Mr. G. K. Gilbert measured the following sectiou (Geog. and Geol. Expl. and Surv, West 100th Merid., vol. iii, p. 1G7), from the top downward: I'eet 1. Gray, inaHsivo limestoiio 2(K) 2. Bl;ie-gray, calcareous Hlialo SJUO Fossils (as corrected by C. D. W): Acrothele suhsidua, Jgnostus inter- striclus, Olenoides Nevadensls, Ftyohoparia Kingi, P. Housensin^ and Aaaiihiscua WheelerL 3. Gray limestone, light and dark, chiefly massive 900 4. Vitreous sandstone, nmbor-hrowu on weathered face; base not seen 1,000 Total ..'. '. '2,:iOO § 79. No. 4 of this section may be correlated with No. 1 of the Eureka and Highland sections or No. 12 of the Wasatch section ; and the fos- sil-bearing shale No. 2 is the stratigraphic, lithologic, and i>aleontolo{;ic equivalent of No. 13 of the Highland liange section ; and although theic is but one species in common, Acrothele subsidua, the general facies of the fauna is comparable to that of the fauna of division 13 of the High- land Eange section. CORRELATION OF SECTIONS. § 80. The foregoing sections show that the Middle Cambrian fauna has a distinct stratigraphic position in the Cambrian System and that it is widely distributed over the North American continent. When study- ing the faunas we found that of the Vermont section to be similar to that of the Bic Harbor and L'Anse au Loup first determined by Mr. Billings; and that tho Bic Harbor and the Troy fauna were united by twelve species common to each locality, first determined by Mr. S. W. Ford and Mr. Billings. With llie Nevada area there is a greater differ- ence r but the presence of a pre-Potsdam fauna, characterized by the gene"..'a Olenellus, Olenoides, iind Frotypiis — all of which are found in tlio typical Georgia section — serves to unite them. § 81. Throughout the Mississippi Valley, including the areas of Uj)- per Cambrian in Llano County, Texas, a)id in Wisconsin, nothing is known of the Georgia fauna ; l)ut to tho nortliwest, on the eastern slope of the Bocky jMountains, Dr. George M. Dawson discovered a species of Olenellus like 0. Gilhcrti, also Proli/puH scni'dus, tluis showing tho ex- tension of the fauna north from Southern to Central Nevada, and north- east to Kicking Horse Lake in British Columbia. § 82. In the accompanying table an attempt is made to correlate the principal sections herein mentioned . The Georgia or Olenellus fauna of the Middle Cambrian and the Potsdam or Dici.»Mo'"'pl»alus fauna of ilio Upper Cambrian au taken as the two horizons to locate the local sec- tions on the line of the great section, as their relations are known iu (7G(i) WAI.COTT.l i I WAI.COTT.l INTRODUCTORY OBSERVATIONS. 41 the unbroken stratigrapliic sections of the Eureka District and the lliyhland Eauyo. § S3. The first section, that of Big Cottonwood Cafion in the Wasatch Mountains, is repveaouted as resting on pre-Canibiitiu rocks, and ex- ti'iiding ui> to the IMiddle Cambrian horizon. The Lower Sihirian (Or- (lovician) strata rest directly on tlie top of tliis section in nature: but we h'ave the hiatus between the MiddUi and Upper Cambrian horizons to show the unconformity, by non- deposition, in this section, as com- piiied with tlie Eureka section, where the hiatus of the Big Cotton- wood section is filled in by several thousand feet of limestone strata containing the fauna that, to a great extent, bridges over the break in the fauna between the toj) of the Big Cottonwood Cambrian and the Silurian strata. § S4. The Eureka section (2) is correlated at its base with section (1) l)y the sti{i'iir''a])hy and contained faxiua. A dark mussive quartzite, ovorIn,ic' l\v 'vies, occurs in each; and this horizon is traced across the int-'M' T!i;(, ^ouu try between the two sections by its occurrence in the Oquia!); 0 intic, and House lianges, and also south of Eureka in the llif^iiland Kange. It is only in the Wasatch section that the great quartz- itic series is ti-aced down towards its base, the uj>lifts of Nevada not hav- ing brought it up, except, possibly, at one point — White's Peak, in the Sc'liell Creek Eange of Eastern Nevada — where Mr. G. K. Gilbert meas- ured a section 11,580 feet thick, thatis very much like that of the Wasatch. Unfortunately no fossils were found (Geog. and Geol. Ex])l. and Surv., West lOOth Alcrid., vol. iii, pp. 107, 171). The Eureka section extends iiljfioni theOIenellus horizon (j,'J(K) feet to where the n])])er limit of the Ciiinbrianis drawn. In the table it is represented on the same scale in its extension up to tlu Tienton horizon of the Lower Silurian (Ordo- vi(Man). § 85. The Ilighlaii (lat' .;« section is essentially n reduplication of tile Eureka sectioi. ji"\', i:ke it, joins on the Wusatch section in the same manner at the oa, < it is not represented in the table. §80. The Grand Cafion >' i'iian and pre-('anibriaii strata (see fig. 5) liave been roughly described by the writer (Anier. Jour. Sci., vol. xxvi, p. 4.")8, 1883). At the top it consists of 1,000 feet of strata cariying a strong and characteristic Upper Cambrian or I'otsdani fauna. Then a great un- conformity occurs by the erosion of an entire cross-section of the 13,000 feet of strata below that rest unco:iforniably on the underlying highly iiic'Hned strata, which, where the section terminated, belong to a system of Htrata between tlv-, 'vand Canon Series and the Archean. In the table tiie period of eru^ !"• i •. represented as having removed all the strata between the Uppei mbriaii and the Lower Cambrian horizon, but I now think it would have been better tu classify all the pre-Tonto strata '!< 'ire-Cambrian. i) *7 This to a certain extent is hypothetical, but we know from the (767) 1 '■ii ;* I ■m li 42 CAMBklAN FAUNAS OF NORTH AMERICA. [UL-LI,. 30. ■ V' ■ U:' 11 •» 01 o g ■1 1 la rt 6 .a O a tt o e 0 'A i .a rt ''. ST ■3 T. ? * i,) F- St cC " 0) »-* •= £ o p. i J WAICOTT.] (768) WALCOTT.] INTRODUCTORY OBSERVATIONS. 43 ])hy8ical conditions of the unconformity that a great period of erosion existed whose duration might readily have permitted of the deposition of tlie great series of strata that occur below the Upper Cambrian, over the area of Utah and Nevada. I now think that in the Grand Canon section the Middle Cambrian and the Lower Cambrian were periods of erosion, and not represented in the section, and that the 4,000 or 5,000 feet of limestone of the Eureka and Highland sections and the (letrital sediments of the Wasatch section are the deposits accumu- lated in the sea of the Great Basin area when the area of the Grand Canon was a land surface. The latter was of considerable extent, as essentially the same section as that of the Grand Canon of the Col- orado occurs in Llano County, Central Texas, and in Minnesota and Wisconsin. § 88. The strata of the older series of the Grand Caiion section are in a remarkable condition of preservation, considering their geologic roportional scale as Nos. 1, 2, and 3, although we fully appreciate the fact that a much thin- ner series of strata in one locality may represent the same relative period of deposition in another area where the accumulation of sedi- ment was very much greater. When we attempt in the future to corre- (769) i "' 'I I'-' 44 CAJIliUIAN FAUNAS OF NORTH AMERICA. liiri.l..30 f'" ■■v It'-'*. , ■■ iU ■|v.:, , I Table showing the correlations of tsrpical Cambrian Sections with reference to the Potsdam and Georgia faunas of the Cambrian. 1 ORDOVIGIAN- or - 1 X 2 . 3 4 5 LOWER SILURIAN. 1 1 1 1 / 1 / 1 / ! . / 1 1 1 ^ Upper Limit of -^ I . ' ---''■' Upper Cambrian or Potsdam horizon. fS — t \ > d O 1 { UPPER CAMBRIAN 1 o: k5 § 1 Mt^ ^ ti 1 = POTSDAM OR ' ^ o 1 ! ^ DICELLOCEPHALUS. 1 S 1 1 S / -1 1 1 tin .1 o MIDDLE CAMBRIAN o u "" (3 o Central horizon of Middle Cambrian __- o 1^ QD = GEORGIA OR OLENELLUS. !^ ^ • • ? M ^ y LOWER CAMBRIAN 4 d a = ST. JOHN SERIES. A I ' NEWFOUNDLAND AND > ^ % o o o 1 BRAINTREE, MASS,, OR 1 i o o o PARADOXIDES. CO" V V , «" ni Base of Cambrian. — S- cS . PRE- CAMBRIAN cUidARCHEAN. ? 1 < Palseophyona Cruziana sp.C (770) ym lmu..3o WAIX-OTT.) INTKODUCTOftY OBSERVATIONS. 45 H ":^: late the various sections and fiiunas of the entire Cambrian System of North America, all the sections will be drawn on a plan, so that the divisions of each section will show their relations to each other as far as practicable. The Vermont section is placed on the Middle Cambrinu line by the evidence given by its contained fauna. § 91. Section 5 shows the Upper Cambrian horizon and the Lower Silu- rian section up to the top of the Trenton limestone as developed in Xew York State. The Middle Cambrisin is unknown to me in New York ex- cept east of the Hudson River, although it may occur in the southeastern portions of the State. The Troy and other sections of the Middle Cambrian on a line south of the Georgia section are included under section 4 of the table; also, that of the Straits of Belle Isle. § 92. The object ( ' the table being to show the stratigraphic rela. tionsof the three divisions of the Cambrian fauna, many details are omitted that may be expected when a review of the Di)per Cambrian or Potsdam fauna is completed. ■m:^ I TABLE OF THE MIDDLE CAMBRIAN FAUNA. § 93. In the following table the extent and character of the fauna are sbown and also its geographic distribution. Under the head of Highland Range we include the fauna at Pioche, in the Ely Range, and the species from the Timpahute Range and Silvfir Peak, Nevada, as they are all from the same geologic horizon and geo- graphic area. Table of distribution of Middle Cambriiin fauna. 4 4J > 1 1 u 3 1 3 a el 9 1 g 1 M 1 a ! i a i cs M t 3 Kxam. X X X .... X X Cru7.iaDasp,(?) SPONGI^. Arclia'ocvftthuw AtlaBticus Billings.. X X S.P. X BiUiosai Walcott sp.? .... .. --..- 8.P. X Edininnbvllura Tjrofandnm Billinfffl X KfinRHelaericnni Ford X X ▼"arum Ford .. .. ... ......... Whltneyi Meek 8.P X ^qitoniilus Zitteli Walnntt X * I'lotdHpongia Tenestrata Salter ^ X X Stripliochotn8»8p.t S.P. X .■Jjj", (771) i . J " ' %l ii^^^ ;■■, ::*V.: 46 CAMBRIAK FAUNAS OP NORTH AMERICA. Table of dinMbution of Middle Cambrian fauna — Continued. [bum. 30. HTDKOZOA. Diplograptns ? Rlmplex EnunonB Cliiuacugruptu8?1 Emmonai Walcott. CKINOIDEA. EoisyBtiteg?) longidactylns Walcott . Jap.? ANNELIDA. Areiilirolitns sp.f . BRACKtOPODA. Liiignlella ca3lata Hall (ap.)- Ellan.&W Kntorgina cinij^lata Billings Labrartorica Billings . . pannula Whitti (sp.) ... Prospectensis Walcott. Ipliiilea bflla Billings Aciotrota gemma Billtuga Aiirothelo Hiibsidua White Ubolulla chroniatica Billings ... Ciruo Billings crassa Hall (sp.) gemma Billings nitida Ford Orthis Bighlaudensis Walcott Orthisiua fostinata Billings oriontulis Whitfield 1 transTersa Walcott ? (sp. undetermined) 28p.? sp.? CamaroUa? nntiqnata Billings Jsp.? LAMELUBRANCHIATA. Fordilla Xroyonsis Barrande GASTEROPODA. Stenotheca 1 olongata Walcott rugosa Hall (sp.) Sconclla conula Walcott reticulata Billings retuaaFord ! vaiians Walcott Platycerns pvlmwvura Billings if I I 8.P, » a u M 0 ^!« Lcperditia Arjj Tro I'rotocaris Mat (772) •J BUI.U 50. WALCOTT.] INTRODUCTORY OBSERVATIONS. 47 Table of disttihuiion of Middle Camliriaii fauna — Continued. (' i 5 ^ X f . i Georgia, Vt. 1 n o X x' o 1 •6 1 -a a 1 1 >5 X 1 08 1 1 .a u i 1 1 t •3 s PTEROPODA. HvolitliBH Amf^ricunufl BilliiiiTM . . ... ..... Bi1liui;8i WiUcott x» X cotniiiQDiH I3illitiirs ............... X X X var. KniiuoDHi Ford • 1 DrinconH Billin^H ....... ................... X S.P. X .... Hp, (uiidotorniunMl) X X X X X X CRUSTACEA. Leperdilitt Argent a Walcott X Trovenais Ford -. X I'mtofuris Murnbi Walcott .... X PCECILOPODA. A li^noHtufl intcratrictus Whito .. . • X iiobiliH Ford .. . X HI).? . X X MicrodiscuH lobutus Hull (sp.) - X X Meeki Ford Parked "Walcott X X X Meflonjicis Vomioiitaiia HalWflT) ) . . X X Gilberti Meek X X X X X — X Itldingsl Walcott ... Thoiiipsoni Hall .. . .. ....•..-• X X X Olenoides Uafiricaiulus White (sp.) X X lovi» WiUcott X '( Marcoui Wliitfleld (sp.) X X quadriceps Hall & Whitfield (sp.) X .... X tvpicalis Walcott X X Wabsatchensis Hall & Whitfield Until vnotus holopvga Hall X X I'tyclioparia Adanisi Billings X Hou.seuBis Walcott X X KingiMeek (sn.) raiser Billings (sp.) X Piocliensis Walcott X ? I'nwpecten.sis Walcott qiuidians Hall & Whitfield (.sp.) X X subcoi'onata Hall & Whitfield (sp.) (A) stienuus Billings .... X .... .... .... ■ • •• (773) M m ■4 'tf »| >.icophaln8 Augusta AValcott X X X Llliana Wnlcott Orv*'^0(;epliJiluH piimiin Wttlcott AnoniiH'art) parvutn AValcott i X Protypufl Ilitclicocki Whitfield (sp. ) X X sonectus BUIId^b (sp.) ... X X X X BiLibviiriaGUS IlowoUi AValcott X X productus H. & "W, (sp.) X X 8UMMAUY OF FAUNA. § 94. The total fauna, as known to me, includes 43 genera, 107 spe- cies, and 2 varieties: AlgOQ Spongiaj llydrozoa Crinoidea Annelida Hracliiopoda Lamellibranchiata Gasteropodii I'teropoda (1 variety) Crustacea PtBcilopoda (1 variety) Total a O I) 14 10 I 1 43 KIT § 95. Of the above, 14 species are not described in the text. Five ot these are from ('anada and have not yet been named or described, \ iz: 2 species, Orthis; 1 species, Pt.vclio]>.'iria; 1 .species, Ciiiiiarella; iniarated by .'),(UI() feet or more of limestone. Bnt three species, Protospovfjiafevcairaia, Stcnothcca ehwfjdta, and Acrotreta gniDiia, are known to pass np to the l'i)per C^ambrian or Potsdam hori- zon. In the tieorjiia section, Vermont, one t)f the si)ec!es, I'tt/chopdria Adamni, appears to ])ass np into liie hori/on of the "h-ntile" (!)) of the section, where the faniia is more like that of the Potsdam; and, of the other 8i)ecies, Orthisiua oriexfolis is mnch like 0. rhi(! area is about Con- ception Bay, Newfoundland. At Topsail Head about KM) feet of lime- stone is exposed, overlaid by a dark shale. AH stratigraphic coujiectiou with other sections in the vicinity is broken. The fossils in the lime- stone are not numerous, but j\ir. Billings pronounced them Potsdam (Gcol. Newfoundland, }). bj7; reprint of report for IS(iS), and identi- fied Salterella and Crania {Kutorijina) Lahradorica, and I found in the collections of the Geological Survey of Canada Sveiiella ntlcnlaia, Ste- nofheca rugoso, Iphidea hella, and Frotypm acncctm yar.parrnhis, whi(!h S'ives six species that are also known from the JMiddle Cambrian h(ni/on of L'Anse au Louj).' Special stress is i)laced by the writer on the occur- rence of these fossils at To])sail Head, as it is in the midst of the Par- adoxides basin. ]\Ir. Alexander ]Muiray correlated the Toi)sail Head limestone with that of other localities, and ])laces it beneatli the Para- •loxides-bearing shales of St. Mary's Bay (on the page cited above), hui without paleontologic or stratigra])hi(! eviongia, Lingiilclla, Kutorfjina, Acrotreta, Orthis, Hyolithes, Stenotheca, Agnostus, MicTodiscus ?, and Ptyohopariacontinueon up into the Potsdam orUpper Cambrian horizon, leaving but four genera that are common to the Middle antl Lower Cam- brian horizons. One genus, Dendro^raptus, is doubtfully identified in the Paradoxides horizon of New Brunswick, and occurs in the Ui)i)er Cambrian, but is, as yet. unknown in the Middle Cambrian. The geiins Agraulos is also found m tlie Lower and Upper, but not in the Middle Cambrian. Of species, not one of the Gl of the Ameiictan Lower Cam briau fauna are known to occur in the Middle Cambrian fauna, whicii, with its 107 spcicies, stands out clearly from the older fauna and also from the more rectit Potsdam fauna, as but 3 of its species, iVo/« apongiafcnestrata, Stenotheca. eUmgata, and Acrotreta gemma, are known to be common to them ; and ^.0 of the genera in the Middle Cambriiui are not known to i)ass up into the Potsdam or into the Lower Silurian (Ordovician) fauna. Not one species is known to be ctmimon to tlic Lower and Uj)per Cambrian horizons. GENP.TIAL PALEONTOLOGIO CHARACTEUS OF TUE FAUNA. §t)9. Owing to the obscure cliaraeter of the two species of Palicoi)Ii,y- eu8,it is difticnlt to say that tlio> were not formed by tilling in of worm borings or the trails of some annelid or moUusk. Cruziana 1 now \w- lieve to have been a ftntoid, and hope soon to present the reasons for tiie belief, as a beautiful series of specimens was obtained from theUi)i)er ('ambrian strata of the section in the Grand CaSon of the Colorado, Arizona. SPONGIiE. § 100. The sponges r^f the Middle Cambrian bid fair to form one of the important elements of the fauna, as they now include 5 genera and 10 species, and the collecting at Silver Peak, one of the most prolific localities in Nevada, has been of a supexficial character. Ethmophiilhm profundum grows to a large size and is, as describe*! by Prof. Alpheiis Hyatt, the reef builder of its time. (Science, vol. vi, p. 380, 1885.1 Archaoeyathus Atlanticus, another prolific ibrm, has a wide geographic range, as we find it both in Labrador and Nevada. (776) li^l "mw flkVCOTT.] INTBODUCTORY OBSERVATIONS. 51 4 Tho genus Ethmophyllum is a very intereHtiiifj form, for in it wo oh- 8('rvo tbe septa, vesicular striictnrt', and porilrrons .system liiat Ijitor, in Paleozoic time, appear in the vaiious divisions of tlie Zoantliaria brunch of tho .\ctinozoa (Zaphn'ntis, Cystiphylhim, I'avositcs, &c.); to ini!lndo Arcliaiocyathns and allied {^cncia, I>i'. IWnneniann lias pro- poHi'd a new (dass of the Cddentcrala, which he calls Ardiieoeyatliinie. Li'ptomitus Zitteli in the only r('i)r('senfative we have in the Cambrian ehowing the base or root of tin- " an(rhorin}ir sponji;es." I'rotOHpongia fencHlrnta ranpss nearly thronf;h the Candnian of Wales, iiccording to Dr. Uicks; and in America (he genns, if not the species, is now known from both the jjower Cand)rian of New Unmswick and the upper portions of the Middle Canduian of Nevada, the great ver- tical range being accompanied by a corresjjondingly wide geogra])hic distribution. Like most of the other Cambrian sponges (here is not enough known of its structure to accurately place it in the ciassitica- tlon of the Hexactinellidce. The minute structure of Arelueocyathus ami Ethmophyllum is not well shown in the Cand)rian si)eciinens, owing, in all probability, to the destruction of the spiouhe in the replacement by calcite. In the one sihcified species, Efhmophnllnm Mingnnemift^ from the Lower Silurian, tho spiculai are preserved, aiul in Archo rya- thuH r'Uingui w^e observe what appear to be spicuhe in the cup and iu- ters*^ spaces, but not in the walls or septa. IIYDROZOA. § 101. BipJograptiis ? simplex is a form allied to the leaf-like grai)to- litt's of the Lower Silurian (Phyllogra])tus), but we know too little of the species to even give it a proi)er generic reference ; the same may be said of the species referred to Climacograptus ? Emmonsi. All we can say of them is that they represent the graptolida^ at the horizon of tho Middle Cambrian. Matthew recogni/es two getiera of grai)(olites in the St. John Group, Dendrograptus and Protogniptus; the former being found in the Upper Cambrian (Potsdam) horizon shows that the type ranges through the Cambrian System. 1 t?} '^■4 m m ^§ .'' .UK' ECniNODKllMATA. § i(Yl. A giance at tho figures illustrating Eocy^tltesff lotigidacti/lus shows that we have not yet reached a simple type of the Cystoidea in this Cambrian fauna, although, in the irregular size and groat number of the plates, the pore-like openings at their margins, and (he long simple arms, a general looseness of organization is indicated that is wanting in the comi)act, regular forms of the siqierior fauna. The genus was founded on single plates from the St. John Group; ami s;>incwhat similar plates occur iu the Wisconsin Potsdam sandstone. Until entire or nearly entire specimens are I'ouml from these horizons, 've cannot compare tho E.ff lonf/hlactijtKs with what these plates repre- sent. (777) m S>!. 62 I M iii ~M\ CAMBRIAN FAUNAS OP NOT?TH AMERICA. BUACHIOPODA. ( BULL, 80. § 103. Nine geiieni and 24 species from the Middle Cambrian, and 6 genera, with 12 specios (Matthew), from the Lower Cambrian of Aiiierica, show a total of 10 genera an;)er, and the 3 remaining genera the Siphonotretida', if we may use the latter as a subfamily. Obolella first appears as O. maculata Hicks in the Paiadoxides horizon (Lower Cara- bri'.iii) of Wales, and reaches its greatest development in the Middle Can\biian horizon of America, fioin which 5 well detined species have been recognized. From the Upper Cambrian we at present know of but 2 sjiecies that will be retained in ihe genus. The chara(;ters of the genus are well shown by the figures on ])lat"S iy and x. The genera Aero- treta, Iphidea, and Acrothele belong to a natuial group having a conical ventral valve ])ei ."orate at the a])ex, wit li more or less of a false area and a dejjressed dorsal valve. Acrothele is considered by its author as most nearly related to the genera Obolella and Acrotreta, but, from the in- forn'ation >V'^ now ha-, e, I would place it nearer to the latter and still nearv^r to the geiius S(diiza!id>()n (Monographs United States (leolog- ical fciurvey, vol. viii, j). ()!»). Tl'.e genus Kutorgina has a wide geographic distribution and a vertical range from the Lowei- Ca nbrian of Sweden and New Urunswiek up thro igh tlie MidV.e Cambrian, where it reaches its greate«L (levc'<>i> nient as now known, into the U})per (Jandjrian of Nev.ida and Montana, arrande suggests that tiie little shell Fordilla Troj/ensis may be the valves of a crustacean, but, at the same time, calls attention to its resemblance to shells ot the genus Xucula; and 3Ir. Ford noticed the resemblance of the single valves to a small Modiolopsis. I think tiiat it is a laniellibranchiate shell, but there is an element of uncer- tainty owning to the obscure (sharacter of the muscular, impressions. If a true lamellibranch it is tiie earliest now known, and the recoid of the class is not taken uj) again until the passage beds between the C!am- brian and Lower Silurian (Ordovician) are met with. Jt cannot be tluii Euvha,s»u( BJumenhadd Billir.gs of the Calciferous formation ((ieol. Can., Pal. Foss., vol. i, p. 3Gi, tig. ^^48) is the first of its class, judging from its size and its relation to the genus Conocardiuni. Eopteria typica, E, Bichardsoni, and J'J. ^ ornata Billings (Ibid., i)p. 221, liOG, .SOT) conijjlete the list of the Calciferous sj)e(!ies, and, like E. Blumenbachi, arc far in advance of what one would anticipate of the first of the family to which they are referred (Aviculidie). GASTERf)PODA. § 109. The type represented by Stenotheca ruffOfid ranges through- out tlie Cambrian, ami is ioany Mr. G. F. Matthew, and that of the Upper Cambrian by myself, and probably within two years the Cambrian fauna of North America will be known to include more than 100 genera and 400 species, as to-day tliere are 92 genera and 393 species published that I have included in tiio fauna. Besides these there are a number of genera and species not included that may not be based on organic remains or are synonyms of some of those that are included. m 4 if ■. '! A' i ii I J! Summary of the Cambrian faunas of North America, by genera. Lower. Middle. Upper. No. of Cenera. Ko.of species. AI.QM. x-1 x-1 x-1 y-4 1 1 1 2 1 x-2 6 Totals 2-3 3-0 3 9 SP0NGI2B. Ai'cliffiocvatliiift ..... .... ............... 1 1 X 1 X 3 1 1 1 1 1 1 4 Kocorvnfi . ..... .... ............... 1 KllinionhvUnm ... ..................... X 4 X 1 X 1 X 1 4 1 X 1 X 1 9, Si riipljocliottis 1 Totals 3-3 5-10 1-1 6 13 HTDROZOA. X 1 1 1 1 X 1 X 1 2 DinloffrantiiB X 1 ...1 1 1 X 1 1 1 Totals 2-2 2-2 1-1-|_ 4 6 CRINOIDEA. Eocvstitca X 1 X 2 1-1 1 3 ANITELIDA. Aronicolites ... ... .....i.... ...... t 1 1 1 X 2 1 4 ScoUthns 1 X 1 1 1 1 Totals. „ 1-1 1-1 2-3 2 6 (785) I B^ii i' > 60 CAMBRIAN f^AUNAS OP NORTH AMERICA. tBciuo Summary hf the Cambrian faunag of North America by genera — Continued. Lower. Middle. Upper. No. of genera. No. of specieH. BRACHIOPOOA. Aorotrota X 2 X 1 X 1 X 1 X 2 X 1 4 2 Aorothele . . ............ Camarella X 1 X 2 Disoina? Iphidea X 1 X 4 I g Kutorgiua X 2 X 2 X 2 X 8 X 8 X 0 Leptwna LiDKulu 1 3 a Liii£ulella y 8 X 2 » LinnarHDonia X 2 OboIelUi . . X 5 X 1 X 7 X 4 X 3 X 1 X 1 () OrthiB X 2 II OriibisiDa ){ Triplesia Totals 8-12 0-24 12-32 15 67 LAMELLIBKANCHIATA. FordlUa X 1 1 1 GASTEROPODA, fiellorophon X 1 X 1 X 1 1 BiUiiigsia 1 Kiiomphalns 1 Harttia X 1 J Holopea X 1 X 1 X 1 X 1 X 2 X 3 X 1 1 Maolarea 1 Metoptoma 1 OphUeta 1 Paloiacmea o Platyceras X 1 4 Pleurotomaria 1 Scenella. X 4 X 2 4 Stenotheoa X 6 1 1 X 1 g Straparollina 1 Totals . 3-8 3-7 11-14 • 14 — ._ 20 PTEROPODA. Diplotheca X 2 2 HyolithelluB X 1 X 6 X 2 1 Hyolithes X B X 3 14 SaltereUa 2 Serpnlites .......... X 1 1 Totals 2-7 8-9 2-4 5 20 CRUSTACEA. Beyiichona X 2 2 Climactichnites X 1 1 Hipponicharion - X 1 X 2 1 Lepidilla 2 Leperditia X 2 • X 2 4 Lepldltta - X 1 1 Notbozoe X 1 1 PrimitUI :, : X 1 86) I (7 wALcorr.J INTRODUCTORY OBSERVATIONS. 61 Summary of the Cambrian faunaa of North America, hy genera — Cuutinued. CRUSTACEA— Continued. Protichnltea ProtooariB Totals. FCEOILOPODA. Aglaspis Agraalos A gnostna Amphiont Anopolenns Anomooare Arethusina AHaphisons Batbynotns ■. Batbynrnst Buthyurisons Chariocephalns Couoooryphe Crepicephalna Ctenocephalna Dicellocephalns niwnuma MeRonacia. Microdiscns Ogygia? Olenellas Olenoidea Olenng Oryctocephalns Paradoxidea Pemphigaspia Ptotypna Ptychaapis Ptychoparia (and anbgenera) Solenopleura Triarthrella Totida. Upper Cambrian. . Middle Cambrian . Lower Cambrian. . Reappearances. Total fauna — Lower. 6-7 X 5 X 8 X 1 K 3 K 1 X 2 X 8 X 6 X 1 Middle. X 1 2-3 Upper. X 1 4-6 X 3 X 1 X 1 X 1 X 2 X 2 X 1 X 4 X 4 X 8 X 1 X U X 1 X 2 X 10 X 15 X 1 X 1 X 12 X 2 No. of genera. 10 X 1 X 29 X 1 » 1 X 1 X 1 X 1 X 7 X 6U X 1 »^5 14-45 I 10-146 No of apucies. IS 15 12 O 2 3 •29 80 1 226 StratigrapMo r^sumS. Genera. 52 43 32 SpeciuB. 127 35 92 213 107 70 306 3 393 (787) 'P: '; '^-. !f V ■■ i CAMBRIAN FAUNAS OF NOBTH AMERICA. Zodlogic ri»um4. [BVLU 30. AlgB SponRias n.ydrozoa Ciinoidea Annelida ISrachiopoda Lamellibranohlata Gasteropoda Pteropoda Crastaoea... FoBcilopoda 0«Berft. 02 Specie!. !l n 5 3 :i 15 67 1 14 29 20 10 15 81 22(1 39» § 131. Oenera limited to the Lower Cambrian. — Eocoryne, Protograj)- tus, Liunarssouia, Harttia, DiplotUeca, Beyrichona, Hipponicbarion, Lepidilla, Lepiditta. Priuiitia ?, Paradoxides, Aoopolenus, Conoco- ryphe, and Ctenocei)lialu8. § 132. Genera limited to the Middle Cambrian. — Etbmophyllum, Lepto- niitus, Iphidea, Fordilla, Scenella, Hyolitliellus, Salterella, ProcOcarivS, Anomocare, Asaphiscus, Bathynotus, Batliyuriscus, Mesonacis, Ole- nelliia, Olenoides, Oryctocephalus, and Protypus. § 133. Genera of the Upper Cambrian not occurring in the Middle and Lotcer Cambrian. — Paloeocborda, Scolithus, Discina, Leptaena?, Lingula, Lingulepis, Triplesia, Bellerophon, Billingsia, Euomphalus, Holopea, Maclurea, Metoptoma, Opbileta, Palseacinea, Pleurotomaria ?, Serpu- lites, Climacticbuites, Notbozoe, Proticbnites, Aglaspis, Ampbion ?, Aretbusina, Batbyurus ?, Cbariocepbalus, Dicellocepbalus, Illaenurus, Ogygia?, Olenus ?, Peniphigaspis, Ptycbaspis, and Triaribreila. § 134. Genera common to the Lower and Middle Cambrian. — Arcbaecy- atbus, Protospougia, Eocystites, Areuicolites, Acrotreta, Acrotbele, Kutorgiua, Liugulelhi, Oitliis, Stenotbeca, Hyolitbes, Agnostus, Micro- discus, Ptyclioparia and subgenera, and Solenopleura. § 135. Genera common to the Middle and Upper Cambrian. — Cruziaua, Palseopbycus, Prolospongia, Arenicolites, Eocystites?, Acrotreta, Cani- arella, Kutorgina, Liugulella, Obolella, Ortbis, Ortbisina, Pbityceras, Stenotbeca, Hyolitbes, Leperditia, Agnostus, Crepicepbalus, Micro- discus ?, and Ptycboparia. § 136. Genera common to the Lower and Upper Cambrian. — Den(bo- graptus, Arenicolites, Eocystites ?, Acrotreta, Kutorgina, Liugulella, Ortbis, Stenotbeca, Hyolitbes, Agraulos, .A.gnostus, Microdiscus '?, and Ptycboparia. §137. Genera common to the Lower, Middle, and Upper Cambrian.— Protospougia, Arenicolites, Eocystites?, Acrotreta, Kutorgina, Lingu- leiJa, Ortbis, Stenotbeca, H; olitbes, Agnostus, Microdiscus ?, and Pty- cboparia. (788) Km WAI.COTT.) INTKODUCTORY OBSERVATIONS. 63 § 138. Of the 52 genera in the Upper Cambrian, 17 may be said to be typical of the Second fauna, viz, Diaciua, Liugula, Lepttena, Ortliis, Triplegia, Bellerophon, Euomphalus, Ilolopea, Maclnrea, Metoptonui, Opliileta, Plenrotomaria, Hyolitliea, Serpulites, Ampliion, Bathyurus, and Ogygia. Of the above genera, Discina, Plenrotomaria, Ampliion, Bathyurus, and Ogygia are doubtfnlly identified in the Cambrian. Sev- eral other genera pass np into the base of the Lower Silurian (Ordo vician), but are not considered as typical of the Second fauna. § 139. When an accurate stratigraphic and paleoutologic study is made of the passage beds between the Cambrian and Lower Silurian (Ordovician) systems, or the Potsdam and Calciferous Formations of the New York and Canadian sections, we shall possess the data upon which to comi)are the faunas of the two sections. At present thi.s knowledge is, to a large extent, wanting. CLASSIFICATION OF NORTH AMERICAN CAMBRIAN BOCKS. § 140. The following table expresses my view of the classification of the various formations that go to make up the Cambrian system of North America. It is subject to revision in details, but the main di- visions are based on paleoutologic and stratigraphic data that I think will render them of service in the permanent classification of American Paleozoic rocks. The faunas of the Lower Calciferous unite the characters of those of the Upper Cambrian and Lower Silurian (Ordovician), and it will often be difficult to determine to which system the strata containing them should be referred. Clas»ification of North American Cambrian rocks. UPPER CAMBEIAN. Lower Calciferous. Potsdam. Knox. Tonto. Lower portion of the Calciferous Formation of New York and Canada. Lower Magnesinn of Wis- consin, Missouri, &o. Potsdam of New York, Canada, Wisconsin, Texaa, ■Wyoming, Jlont.ana, and Nevada; Tonto of Arizona 1 Kno.x Shnlos of Tennessee, GeorKia, and Alabama. The Alabama section may extend down into the Middle Cambrian. MIDDLE CAMBKIAN. Geor}:ia. L'Ansc ail Loup. Prospect Georgia Formation of Vermont, Canada, and New York. Limestone.s uf L'An.<(!au Loup, Labrador. Lower p.ivt of Cumbrian section of Eureka and Highland liange, Nevada. LTppor portion of Wasatch Cambrian section, TJtali. LOWJSE CAMBRIAN. St John. Bralntree. Newfonndland. Wasiitcli. Tennesson. ? Paradoxides beds of Braintrec, Mass., St. John, New Bmnswick. St. John's area of Newfoundland. Lower portion of Wasatch section, Utah. Tlje Oeoee conglomerate and slates of East Ten- nessee are somewhat doubtfully included. I I ■I (789) 64 CAMBRIAN FAUNAS OP NOUTII AMERICA. |BULU,10. WAUOTT 1 I ' |t*,:r'.:, < The Grand Caflon, Lhino, and Keweenaw series are probably of pre- Cambrian a'^e, and are omitted from the Lower Cambrian, altliough I have heretofore made }• provision. il reference of them to the Cambrian. § 141. The first systematic arrangement of the formations of the Cam- brian system of North America is that baaed on the pa1eontoIo|;ic work of Mr. E. Billings by Sir William Logan. The Cambrian as a system is not recognized, the formations from the "St. John's group" to tlie Iludson River group, inclusive, being placed under the Lower Silurian. Owing to its historic interest and value as a contribution to stratigrapliic, geology, the table is given complete as found on page 46 of the Report of the Geological Survey of Newfoundland for 1805: EngUsh Synonyms. Caradoo Caradooi ... Llandeilo . . . Tremadoc ... J Lingula flags, i Complete SBries. 12. HiulHon Eiver 11. Utloa 10. Trenton groap 9. Chajiy 8. Sillery ] 7. Lanzon y Quebec gronp. 8, Levis J 5. Uppor CnlclferouH 4. Iiower Cslciforons il. Upper Potsdnu 2. Lower Potadam 1. St. John's gronp Western Basin. Hudson Biver . mica Trenton gronp. Cliazy L. Caloiferous . U. I'otsdam L. Potsdam ) . Eastern Basin. SiUery. . Lauzon . Levis... L. Potsdam St. John's group. Kowfonndlud. Sillery. Lanson. Levis. V. Calciferoaa. L. Calciferonn. V. Potsdiuf . L. Potsdam. St. John's gronp. In commenting on the table the author said: It thiiB appears tbat tho lower portioa of the series is complete in Newfoundland nud the upper in Now York and Central Canada. Divisions 3, 4, and 5 have not yet been recoRnizod in tlio eastern continental region. The St. John's group, 1, is represented at St. John, New Brunswick, by 3,000 feet of black slates and sandstones, whoso fauna, described by Mr. Hartt, was correctly refened by him to Etago C of Barraudc's Prii .ordial zone. It there reposes on older schistose rocks, as yet unstudied, but by Mcsrs. Hartt and Matthews designated as Cambrian. Tho slates of St. John's, Newfoundland, and the paradoxides beds of Braintreo, Massachusetts, also probably bolong to tho same horizon. . The Lower Potsdam, 2, is represented by several hundred feet of limestones and sandstones on tho Straits of Belle Isle and on White Bay> in Newfoundland, and by the slates of St. Albans and Georgia, Vermont. The Upper Potsdam, 3, is that of Wisconsin and Minnesota, represented in tho typical Potsdam of New York, which is overlaid by the Lower Calciferous, 4, while the Upper Calciferous, 5, is only recognized in the northern peninsula of Newfomid- land. In addition I wish to add that number 1 is the Lower Cambrian, num- ber 2 the Middle Cambrian, and number 3 the Upper Cambrian of this paper. The additions made to our knowledge of number 2 since 1806 have been the discovery of the Georgia fauna about and below Troy, in the Hudson River valley, by Mr. S. W. Ford; the discovery of tbe same fauna at Eureka and at various other localities in Nevada and (790) Utah by Lake, B paper I own inv< ontologi uecessar §142. be used fauna of rily be d iiig the WAUOTT ] INTnODUCTOUY OUSEnVATIONfl. 65 Utah by tlie United Stutt'S (Jovcrmneut niirvcyH ; ami at Kicking FTorso Luke, British America, by the Canadian (ft'ol«>;;;if the author of tlie '*Taconi conic System : it is the partial blending of the rocks of the thrftb adjacent systems, the Primary of the Hoosic Ranges upon the east and the New York Trausiti m System on the west with the Taconic, creating thereby many doubts and perplexities as it regards the true limits of either system ; and inasmuch as the whole belt itself of the latter rocks is narrow, doubts are thrown over the whole as it regards the views we are to take of them. It will bo more clearly seen in the following pages how it is that differences of opinion prevail in relation to thi'so rocks. Where they have been cowded together, and especially whore the masses are lithnlogically similar, it is not at all remarkable that the views and opinions of geologists should differ ; besides, under the most favorable circumstances, the lines of demarkation between rocks of diflerent eras are often extreme *y obscured, and cannot be drawn with that evactitudo wo wish, inconsequence of concealment under the soil or other circumstances equally effective to render their extent and relations indistinct and uncertain. § 149. On the following page he again speaks of the diflflculty of rec- ognizing the dift'erences between the Taconic series and the formations of the Champlain Group : Much difficulty is encountered, as has been already hinted, when we attempt to draw the lino of demarkation betwct'u tboshiilcs and slates oast of the Hudson h'ivei' and Lake Champlain and the slates of the Taconic System. So nearly do the latter resemble the former in lithologicul characters th;u in specimens of small size the one niiglit be mist.akon for the other. B.it t lis is a common difUculty, or one common to all rocks of the same lithologicial idiaracters, and it is not to be considenul as a posi- tivo objection to the separation which I now i»ropo8 .. (792) WaLCOTT.]. INTRODUCTORY OBSERVATIONS. #7 Tliere are two or three other points it may bf» well to state in this place -• One is in rejjard to the condition of the country alon/r the line of j>.nction of these and of iiliiumt all other rocks: thnre is, for example, a concealment of the strata by rooks and earth for quite a wide space, covering the termination of the masses on either (tide ; added to this difficulty is the confusion created by the gicat sameness in the direction of dip, and as both are lithologically slates or shales and both liable to certain changer, in their planes of straril^cation and of deposition, a wide door is openod, throngh which we may run into mistakes and crei^to confusion. In fact, it often happens that where eitlicr of these difficnlties exists a?one ppecial care has to liii taken to avoid error ; but where they all appear, as in the instance under eon- sidtiration, we can scarcely expect to escape falling into some grfws mistake, that es- pecially which concerns the designation of the rock. § 150. Dr. Eminons, after raeutiouiug the question of the relations of the T5U5onic and Cbamplaiu Groups and deciding: that tbey are tuade up of strata belonging to two distinct geologic systems, proceeds to discuss the lithologic characters of the series (pages 138, 139, 140), and says in conclusion (p. 140) : If the preceding views are admissible, there is sufficient reason for regarding the roeks which lie between the upper members of the Chaniplaiu Group and the Hoosic Moiiutaiu as a distinct series at least ; but I would remark that by the expression "lying between" I have reference to geographical position, for, considered geologic- iilly. they can be regarded in no other liglit than .as inferior to the Potsdam saiulstouo or iiH having been deposited at an era eailirr than the lowest member of the New Yf ik Transition System. We have in no instan je, however, been able to trace a sonneciiou in these masses, and wo have never found the. Potsdam sandstone resting upon any (pf the members of the Taconic System. To attempt to explain this remarkable feature iir fiict would bo premature. The bare fact that the Potsdam sandstone rests on gneiss or granite, without the in. 3rposition of any other rock, we e.irly pointed cmt, ami, commencing our series w^ith it, we find it to be unbroken and uninterrupted up to tiie Ohl Red Sandstone. IJut if we conuuonce an examinatioti at the foot of the lloDsic Mountain, which is gneiss, we p.ass over a series totnally ditl'eretit from tho.se of wliich we have just been speaking, and among wliicli the Potsdam sandstone does not iipiicar, neither a linuistone which can be referred to those of the Chami)lain Group, or slate or shale whicdi can bo recognized as belonging to the New York System. If we are correct in this conclusion, if the Taconic rocks differ as much as has been rep- resented from the Primary and also from the Transition series, then it appears neces- sary that we should adopt views at least somewhat analogous to those expressed in file ]>receding pages. § 1 ol. On page 142 he again calls attention to the "liability to mistake the liinestonesof this system for those which lie adjacent" and the "dif- liiMiIties in distinguishing the slate of the Taconic System." §ir)2. The first section given, illustrating the Taconic System, is on piij^e Hi), and extends from Petersburg, Eensf.elaer County, New York, to Adams, IMassachusetts; and on plate xi Oi the volume five sections arc given " explanatory of tlic Taconic System." In all of them vrc ihul on the east the Hudson River Group, represented a# resting unconform- ably on the "Taconic slote," then the "Sparry limestone" nexteast, and in st'ctioTis 2, 3, and 4 followed by the " Magnesian slate" of the Taconic Moiuitains, which is overlaid by the "Slockbridge limestone," &c. (793) :im vKl yr e I * K ;?N . , ! t-'v 1 , .;,1 i I' HI ill , ,4 ,' ill Mi ;o5'''! CAMBRIAN FAUNAS OF NORTH AMERICA. f BIH.I,. 30, § 153. After describing the "Rocks of the Taconic System" in a gen. eral way the author then takes each formation up in detail, beginniufj with the western mass of slate which is denominated "Taconic Slate" (p. 150). It is the first member of the Taconic series described, and, I think, occupies the position assigned to it by its author as being older than the Potsdanr sandstone of New York, and unconformable to tbe Hudson River shales. § 154. The Sparry limestone is next described, and then follows tlie "Magnesian Slates," the "Stockbridge Limestone." and the "Graiuilar Quartz." § 155. On page 163 various conclusions of a general character are given, and in the eighth we find the "Taconic'' correlated with the Lower Cambrian of Sedgwick : 8. The Taconic rocks apjiear to be equivalent to the Lower Cauibriim of Proi'ossor Sedgwick, and are alone entitled to tbe coiiHideration of belonging to tins syHtciii, the upper portion (of the Cambrian) being tbe lower part of the Silurian System. § 156. The next extended publication by the author of the "Taconic System" is in the Agriculture of New York, vol. i, 1847. Dr. Emmoii,s's view of the presence of a system of rocks older than the Lower Siliuian of the New York section is evident from the following extracts (i)age 40) : In the following pages I believe the reader will be satlMtied that in these rocks we have, for this country at least, the tine j;aJat object of the writer is to show that the above (piestion has not been .settled right or acconling to facts; or, in otliir words, that the Taconic rocks are not the Hudson Itivor slates and shales in an al- tered state or that all the Cambrian rocks are not Lower Silurian (p. 40). I shall take the broad and distinct ground that the Taconic System occupies a iio- sitiou inferior to the Champlain division of the New York System, or the Lower Divis- ion of the Silurian System of Mr. Mnrcliison. In order to prove that this po.sitidn is well chosen it will be necessary to refer the reader to localities where one system of rocks reposes upon the other, and that I might set this beyond the possibility of ii doubt I have sought thoso points where the slates of the Taconic Sy.stem come in con- tact with the lower limestones, or with the Potsdam sandstone of the New York Sys- tei. r,. r)r>). § 157. In the section (page 63, fig. 7) given as showing the position and t)rder of the Taconic rocks, we find essentially the stune order as in that of the report of 1842, and beneath it the author begins the de.serip tion of the rocks composing the Taconic System with the des(!ripti(»ii of the black slate overlying the "Taconic Slate" and its contained i'os- sils. The "Black Slate" he considered as indicating a distinct rock from the Taconic "Slate, and to be the highest member of the Taconic System. The fossils described are typical of the fauna jireceding the Potsdam iauna, and occupy the stratigraphic position, in relation to the Potsdam series of New York, assigned them by Dr. Emmons. (794) WAI.COTT.] VTALCOTT.] INTRODUCTORY OBSERVATIONS. 69 § 158. lu givinj? its distribution he says (J). 71): ' Tilt' Black Slato is not as well exposed an the Tacouic ; there is, therefore, some iinciTtaiuty iu regard to it. It in the rock adjacent to the Chaniplain and Hudson Vallt'ys, and more frequently tliat which we observe immediately beneath the calcif- erous sandroek, or cropping out from beneath it. What we see of it is frequently in a crnshed condition, and bounding die Taconic Slate on the west in New York and Vermont. I have not recognized it about Albany or Troy. Greenwich, in WaHhlng- ton County, is the most southern point at which I have observed it. It extends north as far as St. Albans, iu Vermont. I speak of those points which I have in- s[)ected. On St. Albans Bay it is traversed by satin spar. It is also calciferons liere, as well as at numerous points upon Lake Champlain. It crops out beneath the calcifiTous sandstone at Sharpshins, near Burlington. I am unable to form an esti- iDiite of its thickness. § 159. Of the Taconic Slate of tlie 1842 report (section 6) he says (p. 72): The Taconic Slate, with its subordinate beds, occupies almost the whole of Colum- bia, Kensselaer, and Washington Counties. It extends to the base of the Tacouic range of mountains, which divides New York from Massachusetts and Vermont. Ly- ing in its usual inclinect serve to corroborate anil sustain those which are. The facts which bear directly upon the evidtiiu-e ailiidcd to arc superposition, succession, nnconformability, and the iiresence of fo-isils iliNiinct from those of the Silurian System. § 101. On page 12 we have the first proposition to divide the Taconic (795) ■I Hi m '1- y ■ m iM m m 70 CAMBRIAN FAUNAS OF NORTH AMERICA. [nui.i..30. % System into two divisions, Upper and Lower; the Lower to include all the original Taconic of the 1842 and 184G reports, with the exception of a portion of the Taconic Shite and the "Black Slate" of the 1847 report. § 162. The author describes the Upper Division of the Taconic rocks as consisting of nun.v.rous beds of slate alternating with shales, thin- bedded sandstones (some of which are coarse and brecciated), thin- bedded, bluish limestone more or less cherty and red, and brown and pnrple roofing slates. Sections are given that cross the Upper Taconic series at points from Highgate, in Northern Vermont, to Rensselaer County, New Yoru. Some of the sections have been studied since Dr. Emmons examined them, and the fact has been ascertained that he did not, in many instances, recognize the series of north and south faults that break the" continuity of the sections; but, after dedr 'ting all the errors, the Upper Taconic remains as a distinct formation uoneath tlio horizon of the Potsdam sandstone. § 103. In 1859 Dr. Emmons again reiterated his views of the Taconic, System in his little Manual of Geology, tender Taconic System (p. 8i) we read : This system desorves tho special attention of yeologists, for two reasons: 1st. It is probably the base of the sediments. M. It is also probable that it is the Palwozoic base, and, in both '•espects, it must be regard'"! as the oldest series of the sedimentary .class. This system is subdivided into Lower and Upper; the first consists of a conglomerate at the base, succeeded by silicious talcose beds of considerable thickness, in which there are frequently pebbles ; next above are three thick beds of sandstone, separali'd by talcose slates ; these are succi. ded by the Stockbridgo limestone. This is llic marble of Berkshire County, Massachusetts, and which extends from the State of Vermont to Georgia. The Stockbridge limestone is succeeded by a mass of s'ate of great thickness, the upper part of which is suitable for rowflng. The greatest thick- ness of the Lower Taconic rocks is about r),()00 feet. The upper ipiai'tz beds are often vitrilied, while a lower one, still many hundred feet nearer the pyro-crystalline rocks, is a sandstone (p. 85). The upper series we have just described (§ J 62). § 164. Prof. .1. D. Dana considers that most, if not all, of the stnta included by Emmons in his original Taconic is of Lower Silurian (Or dovician) age. Dr. T. S. Hunt holds that the term Taconic should bo restricted to the original or Lower Taconic of Emmons (Trans. Koy. Soo. Can., Taconic Question in Geology, vol. i. p. 217; vol. ii, p. 125, 1883-'S1), a view that appeavs to be the correct one ; and whether geologists will unite with Dr. nunt, and call the series of strata next beneath the Cam- brian Taconian, is a question that is not yet decided, as it is yet un- proven whether such a group exists in the original Taconic area. It appears to exist in other localities where it was described by Dr. Em- mons, and, if this io verified, the term "Taconic" or "Taconian" may receive a final resting plaee in American geologic nomenclature. (796) If^ WALCOTT.] INTRODUCTORY OBSERVATIONS. 71 ACKNOWLEDGMENTS. § 165. To Dr. Alfred E. C. Selwyn and Prof. J. F. Whiteaves, of the Geological Survey of Canada, I am Indebted for the use of a number of the typical specimens described by Mr. E. Billings, in studjdng the Bic Ilarbor and L'Anse au Loup faunas, and also for duplicate specimens of a number of species, without which 1 could not have identified sev- eral species from Vermont. Mr. Edward Hurlburt, of Utica, N. Y., kindly sent for study all of his collection of Georgia fossils from Vermont, iucluding the beautiful relief-specimen of Mesonacie Vermontana. By au arrangement made with Mr. S. W. Ford, he made drawings of the type specimens described by him, several ^ '' ^hich are reproduced in this bulletin. Mr. Ford also kindly pennltteil me to examine his collection at his home. In the collection and preparation of the material from Vermont and New York for study, I have been assisted by Mr. Cooper Curtice, of the Geological Survey. The original drawings are by Mr. J. L. Ridgeway when not otherwise mentioned. (797) m III m ''mi '' n 'I* 'JU L I If iilli ^i*: M riiJ: tkl DESCRIPTION OF THE MIDDLE CAMBRIAN FAUNA. FUCOIDAL REMAINS, TRAILS OF ANNELIDS, ETC. Mr. Billini^s described two species referred to the Algse from the Georgia Qtoui), Pala'ophyats incijnensuwlP.congregatus (Geology of Vermont, vol. ii, pp. 943, 944). Prof. .Jules Marcou mentions the presence of a species of Oldhanua (Bull. Soc. G60I. de France, 3" ser., t. ix, p. 25, 1881); but after examining the specimen labeled by Professor Marcou, and now in the Museum of Comparative Zoology at Cambridge, Mass., and also ex- amining great quantities of the shales at Parker's quarry, it seems that the so called Oldhamia is the result of frost and water action, and is not of organic origin. Tiie Chonenus the species now ])laced under the ; Pal. Fo."8., vol. i, \>. f). Orif/inal dei^cription. — "The only sjiecimen of this s])ecies in the col- lection is a fragment \h inches in length, 14 lines in diameter at the larger and t) lines at the smaller extremity. Where the diameter is 11 lines the cavity of the cup is 4rh lines across, and tlie space between the walls 3 lines. Of the radiating poriferous septa thereare about (!0; they are so irregular that it is only in certain i)Iaces in tinelyiudished see- tidus that the radiated structure can be detected. On one side where tlic specimen is weathered the structure i)resents the api)ear:!nce of a rather (;cmi)act cellular tissue. The form appears to be elongate con- ical, gradually tapering, the surface marked by wide shallow encircling ohiiqiie annulations, from 3 to G lines distant from each other. The outer wall does not seem to be poriferous, but this appearance may be due to the crystalline condition of the rock into which it is conveited." On studying the type sj)ecinientj, 1 observed a small projecting growth lioni the inner wall (i)l. ii, hg. \a) which had begun to show a cen- tral cavity and an inner and outer wall. None of the sev.-tions shows tiic line vesicular structure so i)revalent in E. profundnm, but, in place ttf the regular septa and dissei)iments, we find an irregular system of lliicU arched se])ta and vertical partitions, the openings between tlieuj I'oiining an irregular system of passages or canals, many of which ter- (799) Oi ill , "Uml #1 ; 'At v\ m 74 CAMBRIAN FAUNAS OF NORTIi AMERICA. [BULL. 80. minato jis cul-de-sacs aud others penetrate tlirongli tbc walls, aftbrding communication between the interior and the cup and also between the outer suriace and the interior. In some specimens the interior structure is so irrejjfular that no system of septa can be determined. The specimens referred to this species from Silver Peak, Nevada, aro separated by an interval of 3,000 miles from those at L'Anso an Loup, but I am unable to detect differences of specific value between them. Each has the annulated cylindrical form, pitted surface, irregular walls, the interior skeleton with the irregular system of septa, and verticul partitions with the round or oval system of i)assages running throuj^li and between them. Many of tiie sumller specimens are solid to the center, and may possibly be branches broken off from a central mass; but, so far as we know, all the specimens are simple and not branched. There is also a considerable variation in the mode of arrangement of the canals running through the interior, but I tljiuk all the si)ecimens be- long to one species. Formation and locaUties. — Middle Cambrian, L' Anse an Loup ; on the Straits of Belle Isle, Labrador ; and Silver Peak, Nevada. Longitude 117° 20' E., latitude 380 N. Ethmopl Architoi Archo'oc I'rotocijc The the sp species der Et As sponge leal, ci l/JSj. ARCHJioocyATnus BiLLiNasi n. sp. Plate iii, flg.s. 3, 3o-o. Body of sponge cylindro-conical, annulated; cup deep. Both sur- faces with irregularly depressed, round or oval pores that penetrate thiough the w.alls. Outer walls united by arched, transverse septa that are strengthened by irregular vertical partitions tsubparallel to the outer walls. Numerous small pores penetrate the septa and afford communication between the interseptal spaces which, with the outer pores, gave a free circulation to the water. Skeleton of the walls, septa, and partitions calcareous, apparently solid. In the cup and iu the interseptal spaces where spiculge from without ai)parently could not enter, we find in thin sections numerous small, irregular spicula- like bodies which I think were the spiculiB of the sponge. The relations of this species to A. Atlanticus are shown by the form and by the tendency iu some specimens of the latter to develop trans- verse septa and vertical partitions subparallel to the walls. Specifically they differ, but generically they approach each other quite closely, as may be seen by comparing the figures on plate iii. The species occurs in a purplish limestone, associated with A. Atlan- ticus, Ethmojihyllum profundum, &c. The largest example is a fragment of an elongate cylindro-conical specimen. Its greatest diameter is 15""". Formation and locality. — Middle Cambrian, L'Anso au Loup, Straits of Belle Isle, Labrador. (800) ^m WAI.COTT.] MIDDLE CAMBRIAN FAUNA. 75 Genus ETHMOPHYLLUM Meek. Elhmophyllum Meok, 1868. Amer. Jonr. Sci. and Arts, 2d ser., vol. xlv, p. 02. Jrchcmcyathua Meok, 18(38. Amer. Jour. Sci. aud Arts, 2d ser., vol. xlvi, p. 144. Ai ■ ■ j:: fl •JV,.,; PI 76 CAMBRIAN FAUNAS OF NORTH AMKRICA. [uL'Lu ;io. Tri studying tint Htrncture of TJ. WhUnei/i, E. Miiuiancnsis, E. projnndum, aud E. li'cHiiiielaericKni we tiiul in all an outer poi ilV'tons wall conneetiMJ to an inner wall by .septa, the double walls forming a tijjure that \h e.« 'iudro (!onien, but isonie- times tilled with a vesicular mass, or it may be a l)ui]din,i»' of wall upon wall, as in the outer walls. Tliis is shown by tig. \h of jxlatc i and tig. le of platei V. The outer surfaces of ii-'. MingcmensiH and E. prof nudum show, in large specimens, a concentric (iorrugation or undidation of the sur- face, but in the small and slender specimens this becomes less and less prominent, ai ' in one o""" in diameter it is nearly lost. In E. Whitncjii l)roatum, the septum oi)posite a row of pores bending around each pore. In tiujt they correspond, iu position and form, to the jwres of the inner wall. We have, irom Troy, a specimen with the outer wall removed, that indi- cates a similar row of larger pores than the w idth of the septum. The probabilities are that they indicate openings in the outer wall, but of this there is no positive i)roof. Mr. Ford's type specimen is a cast, nearly all the outer wall being removed, but on a small bit, still remaining, a i)oriferous surface is shown. As far as I know the types of the two genera Archaeocyathellns and Protocyathus, I refer them to Ethmophyllnm, leaving the question of their specific relations an open one. The variation in the nun)ber and in the size of the septa is so great in E. Rensselaer! cam that it will not be Burjuising to find specimens showing gradational forms be- tween the two species. A specimen of E. Whitnei/i, ex.imined since the above was writtc^i, shows the poriferous outer wall removed in places and the larger open- ings on the lines of the septa (fig. 1, pi. iv). Comj)aring these with fig. 3, 1)1. ii [E. profundum) and other specimens, we find that this is owing to the oi)enings in the septa just within the outer wall, as shown in a restoration (tig. 2, pi. iv). In fig. 2/>, pi. v, the outer wall is removed and the openings look like pores leading into the interior. Fig. 3 also shows the same feature. Mr. Billings, in describing the characters of the genus Archaeocya- (802) WAI.CliTI'.l MIDDLE CAMIMJIAN KAl'NA. w tliiis, as found iu tJ. prof a nil urn, E. MimjanniHiH and A. Atlantkus (Pal. Koss., vol. i, p. li'il, 180;")), says: "Tlie followiiij,' arc sonio additioiiiil details of the structure of this re- markable genus: The general iorin, as exhibited by the three speci«'Siit present known, is that of an elongated hollow cone, or, rather, a hollow cylinder with one end narrowed to a point, the smaller extremity being closed and more or less cur>ed; the l.irgei' end open. They thus re- semble certain large species ol Zaphrcnth or Cyathophi/llnm, and, in fact, from their form and septate structure, were at first thought to bo corals. Some of the individuals a])i»ear to have obtained a length of two or three feet, with a diameter of three or four inches. " All of the species are transversely ami more or less deei)ly mark* xl by irregular annulations. The structure consists of an inner thin wall or endotheca, lining the great central cavity, an outer wall or ej)ithe('a, forming the rough external surface, and between theses a system of radiating septa. The outer wall in two of the speciies, A. profinuhtH and A. Mhufnneuftis, is p«'rforated with numerous snndl irregular apei- tares leading «lirectly into the loculi or empty spaces between llie septa. In the third species, A. Atluntivitu, it (the outer wall) appears to have a im Vu). 7. Fio. 0. 4 Fid. 8. Fl(i. C. Kthinopliylliim Miii^iiiicnsis (iiftcr liiHiiigK). Fill. 7. Etlimoiihvlliim Jliu^'iincnsis (iiil!ir};cim'iit ol' siirlaci). Fk!. 8. Etliiii(i|)li,vlliiiii Miii!.'iiii('n.si.s (!<|>i(iilii', cnlar^'ed (o .50 iliniiiftcr.s). compact, smooth suiface, with only a few perforations. The inner wall is vei-y thin, with numerous pores leading from the loculi into the great central cavity. The septa consist of Hiin, Hat plates, arranged longi- tudinally exactly as in the genus Zaplnrntis. They extend from the outer to the inner wall and arc i)erforated with numerous small circular pores, so that the interseptal loculi all couimunicate with each other as well as with the central cavity and the exterior. The loculi are sub- (803) (, si ■ m 1 - \, 1 ! u: ■" > hi i H IF V* -i^. 7« CAMBUTAN FAUNAS OP NORTH AMKTMCA. Imii.i,. :io. «livi(hMl by very tliiii ilisscpinKMitN rcsiMiiUliiiK tlios*- (»f n Cunthnphi/lhim, but Ibcy are iin'^'iihiily (listrilmtrd, bciiij,' in noimc \n\v\s ciilijfly iibscnt iiiid ill «»tlii'r pbices sd imiiscioiis that fbcy coiniilett'ly Hll the lociili with small celKs, (ioiistitutiiiiL,' tlio ' poribMoiis or cellular ti.ssno' nicMiti(»iu'(l ill tile orifrinal de.scri|»rioii of tlio i^enus. Tlie etMitral eavity extcinls lu'aily tlie whole length and (constitutes a larf^e jtroportion of flu^ bulk of the fossil. Helow it. there is a portion of the smaller exireniity or base, uiiieh is eomjiosed only of the outer wall, the sejita, ami tlic dissepiments. The section across this part shows that the in'w septa, which are introduced from time to time, as the diameter increases, do not at first exteiul to tliecies are described under it, most of which, it appears to me, are founded on va/'ietal rather thaii specific characters. The second genus, Coscinocyathus, is separated from Ethmophyl lum (=Arch8eocyathu8) by the presence of quite regular cross-se})ta, in addition to the longitudinal radial septa. This definition would include our species E. BillingsL Fifteen species are described under Coscino- cyathus, many of which are based on external form. The third genus is Anthoinorpha, in which there are irregular cross septa between the radial septa. (806) WALCOtT.] MIDDLE CAMBRIAN FAUNA. 81 The descriptions are only outlined, and, as I have not seen either illustrations or specimens, I wait until Dr. Bornemann publishes his ilhistrated memoir be .ore comparing or criticising the species. The principal paptr^ published by Dr. Bornemann, known to me at present, are: Sur la Classification des Formations Stratifl«^es Anciennes de I'tle de Sardaigne. (Compte-Rendn du 2me Congr^s geol. internat., Bologno, 1881, pp. 1-12, pis. i, ii.) Palaeoutologisches aus deni cambrischen Gebiete von Canalgrande in Sardiuien. (Zeits. deutsch, geol. Gesellsch., xxxv., 2, 1883, s. 270-274.) Cambrische Fossilien von der Insel Sardiuien. (Zeits. deut^ch. geol. Gosellsch., XXX vi., 3, 1884, s. 399-100.) Untersuchungen cambrischer Archaeocyatbus-Formen uiu! ^erwanu- ter Organismeu von der Insel Sardinien. (Zeits. deutsch. geol. Ge- sellsch., xxxvi., 3, 1884, s. 702-706.) Ethmophylltjm Whitneyi Meek. Plate iv, figs. 1, la-h. Ethmophyllum Whitneyi Meek, 18(58. Amer. Jour. Sci, aud Arts, 2d ser., vol. xlv, p. 62. Ethmophyllum gracile Meek, 1868. Idem., ArchaoGiiathus JFIiitneyi Meek, 1868. Amer. Jour. Sci. and Arts, 2d ser., vol. xlvi, p. 144. Archaocyathts gracilis Meek, 1868. Idem. Original description. — ''The specimens of this fovssil contained in the collection are slender, slightly flexuous, arched or nearly straight, and subcylindrical, excepting near the lower end, where they taper to a point, by which they were probably attached. They may have gr „ nrn in tufts or groups, but all the specimens yet seen are single and show no evidences of growing in contact. " To the unassisted eye the external siutii ^e of these corallites, with the •'xception of obscure annular swellinga und constrictions of growth and faintly marked linear septal cosia , seems to be ntarly or quite smooth. When examined under a strong lens, however, it is seen to be beauti- fully punctate, the punctures being minute, of exactly uniform size, and arranged with mathematical regularity in quincunx, and so closely crowded that the little divisions between them are scarcely equal in breadth to the punctures themselves, and form, as it were, an extremely delicate kind of net work. So remarkable i^ the appearance of this l)unotured outer wall that the first question that suggests itself, on ex- amining it under a magnifier, is, whether or not it may be merely an exceedingly delicate Polyzoon incrusting the whole surface. A clear oxainination, however, especially in carefully prepared transverse sec- tions, shows that the punctures actually pass entirely through the wall, which is very thin, and that they fre not due to the growth of the Poly- zoon, nor to surface ornamentation. .if: „ '■%' Bull. 30 G (807) 82 CAMBRIAN FAUNAS OF NORTH AMERICA. I BULL. 30. "On grinding away this very thin punctured wall, the septa are seen immediately within to be stout, equal, straight, and very equidistant, but in grinding a little farther in they are observed to become very regularly waved laterally, exactly like the septa in theforaminiferous genun Fusulina. So striking is this resemblance that it was not until after ascertaining from cross-sections that the fossil has not an involuted structure that I could get rid of the suspicion that it might be a type of Foraminifera allied to Fusulina, instead of an extraordinary coyal. " By grinding still farther in (to a depth of about 0.06 inch, in a speci- men 0.34 inch in diameter), the lateral waving of the septa already men- tioned is seen to be there suddenly and so strongly marked that they connect b'terally in such a manner as to form a kind of complex inuer wall between the great central cavity and the outer septate zone. This wall, however, does not completely isolate the septate outer zone from the central cavity, but is perforated by a series of round equal canals, very regularly placed, one within each of the lateral curves of the septa, so that those on the opposite sides of each septum alternate with exact regularity, as do those of each of the two rows within each interseptal space. These canals have no similarity to the minute punctures of the outer wall, being greatly larger and very differently arranged. They do not pass directly through the inner wall, but :ire directed obliquely upward and inward, so that as seen in transverse sections of the coral- lites they present the appearance of a double row of vesicles cut across. "Both longitudinal and transverse sections show the large central cavity to be without any trace of septa or columella. From these sec- tions I was likewise at first led to believe this central portion to be also an entirely open cavity or calice the whole length of each cora'.Ute, but on sending specimens to Professor Verrill he called my attention to some obscure appearances of transverse plates in one of the specimens cut longitudinally and requested me to cut others with the view of as- certaining whether or not these ai-e plates. A longitudinal section of another specimen, however, when carefully polished, reveals no traces of proper transvere plates ; but when examined by the aid of a strong magnifier it shows the whole interior to bo occupied by a dense vesicu- lar tissue, the walls of the vesicles being of ';X>eme tenuity. This structure is seen in the interseptal spaces of the outer zone, as vt^ell as in the central cavity within. "In regard to the afdnities of so remarkable a type, it seems scarcely safe to express an opinion without a better series of specimens fo»' study. Some of ' s internal characters, as suggested by Professor Ver- rill, would seem to indicate remote affinities to the CyathophylUda; ; but its peculiar perforated outer wall would, on the other hand, appear to remove it from the primary division of corals including that family. " 1 am therefore led to believe it a new genus, and most probably typical of a new family, in which opinion Professor Verrill concurs with me. For this genus 1 would propose the name Ethmophyllum. ' (808) wALCorr. MIDDLE CAMBRIAN FAUNA. "Among the specimens in the collection under examination there are apparently two species of this fossil. That considered the type of the genus is larger and more robust than the other, and more conical in form, especially near its smaller end. None of the specimens seen are quite perfect at the larger extremity. One measures 0.37 inch at its imperfect larger end and seems to have been 2.J to 3 inches in length. In this there are sixty septa, while its outer septate zone is 0.07 inches wide. Another fragment, however, measures 1.20 inch in diameter at the larger end, and was probably 5 to 0 inches or more in length, with 112 septa at the larger end. This large fragment shows that the septate outer zone does not increase in thickness or breadth in 1 retortion with tii3 size of the corallites, since it is only 0.15 inch broad in this specimen, the increase in thickness of this corallite being made up by the increased size of the non-septate interior. For this larger species I would propose the name Ethmophyllum Whitneyi, in honor of Prof. J. D. Whitney, to vhom I am indebted for the use of the speci- mens. " Of the other species I have seen but a single specimen, which is im- perfect at l)oth extremities, about 2.15 inches in length, and only about 0.20 inch iv diameter at the larger end and 0.15 at the smaller, with some 24 to -■ t pta. In addition to its much more slender form, it dif- fers from th«i ulaer species in having its sei)ta so strongly waved later- ally as almost to divide the interseptal spaces into cells, nearly to the outer wall. For this, if it should prove to be a distinct species, I would j)ropose the name Ethmophyllum gracile.''^ A few months later Mr. F. B. Meek wrote Prof. Dana respecting the genera Ethmophyllum and Archieocyathus, and his remarks were printed as follows (Amer. Jour. Sci. and Arts, 2d ser., vol. xlvi, p. 144): *' Since preparing my remarks, published i-, the Journal of Science (Jan. number, p. 62, 1868), on the curious fossil from Nevada, for which I proposed the name Eilimophyllum, I have been led, by further com- parisons, to think it probably not generically distinct from Archccocya- thus of Billings. At any rate, it seems to agree very closely in internal structure with his A. Minganensis and A. profundus. The Nevada spe- cies differs so widely in form and general appearance as scarcely to suggest a comparison with Mr. Billings's species, and, besides, I had derived my impressions of his genus entirely from his typi(;al species, A. Atlanticus, which also differs so materially in internal structure that Mr. Billings suspected it might be generically distinct from ins A. Min- ganensis. If these types are generically identical, however, I can scarcely entertain a doubt but that the Nevada fossil will fall into Mr. Billings's genus, which has priority of date. In this case, the namee of the Nevada species would beoo">': Archococyathus Whitneyi and A. grac- His.'" The original specimens described by Mr. Meek are in the collection ^809) #'l a t i '•Sit J \ i ■'•, '■I 7'<\ I'' 84 CAMBRIAN FAUNAS OF NORTH AMERICA. [Btat. 30. wALCorr. ^'I.Sjf I I of the United States National Museum, and a number of thin Koi'tions have lately been made from some of them that show the details of struct- urti. An examination proves that the typo species is generically thw same as Archceocyathellus EensselaericuH of Ford, and that it is generically identical with Archceoci/athMsprofundus of Billings. The septa join the inner wall regularly when there is no vesicular structure within it, but when the latter is present the septa ternrinate irregularly and the inner wall is imperfectly developed. In the lower and smaller end both walls and septa are regular, the vesicular structure and irregular growth com- ing in with the growth of the individual. The structure is shown by the figures of plate iv. Sometimes the outer wall and septa are broken away, leaving the vesicular interior. I find that the form desci-ibed as E. graeile by Mr. Meek is the result of such an accident, as it corresponds in structure to the vesicular interior of other specimens of E. Whitneyi, We also observe that the thin arched dissepiments between the septa increase in number with the growth, and that where two dissepiments partition otf a cavity between the septa a pore opens into it through one of the adjoining septa. The number of septa in seetions of the same diameter varies considerably, eight to fourteen in sections ll'""' in diameter. The thickness and direction of the septa are also variable in different specimens and in different parts of the same specimen. Frequently the differences might be taken to be of specific value, but I regard them as variations of growth caused by local influences on the individual sponge, such as being crowded by its fellows, fragments of other organisms getting into it, variation in supply of food, &c. In a thin section, tubes two-fifths of a millimeter in diameter appear as simple rings crossed by light bands, which are the interseptal spaees. In other small sections the entire section is solid. As the genus ArchiEOcyathus is restricted to the type species A. At- lanUcus, E. Whitneyi falls back into the genus proposed for it. Formation and locality. — Middle Cambrian. Silver Peak, Western Nevada. The s-^ecies occurs in a limestone and calcareous shale, asso- ciated with Archceocyathus AtlanticuH, fiyclithes jjrinceps, Olertellus Gil- bertij &c. Ethmophyllttm profundum Billings. Plat« 1, i\gl. i,p. 4. Original description. — "Elongate, turbinate, more or less curved, the basal one or two inches sleudei, then rapidly expanding to a diameter of from one to four inches, then beroming cylindrical. The form is that of a large Ctiathophyllnvt or Zapkrentis. The cavity of the cup extends In de[)th nearly to tln' base. Tiio radiating septa are tlun and closely crowded together, there being eight or ten in the width of three lines. The surface is auuulated by strong roagh ridges from three to six lines (8It^) ■v^' WALCorr.l MIDDLE CAMBRIAN FAUNA. 85 distant from each other, the interveninf? larrowa bciug two or three lines deep,. The inner wall of the cup is exceedingly thin, apparentlj- loss than half a line. "In none of the specimens is the outer wall preserved except in «|H>trt, and th^re only partially. The large individuals appear to ha ve attained a length of more than one foot with a dianieter of fronk two tx) four inches," Having received from the Geological Survey of Canada some frag- ments of limestone containing specimens of this species, several thin sections were prepared, from which illustrations have been taken that show most beautifully tht' manner of growth and the minute structure of the organism so far as preserved. The vesiculose character of por- tions of the structure give it the ai)j»earance of a Oystiphylloid coral. Beside the cnp-shaped mode of growth, there are small stems 5'"™ to 10™"' in diameter that are solid to the ceuter, and one pisce 20""" in diameter has no central oi>ening. In sucli examples the septa and dissepiments iire thicker than in the examples with a central opening. In the enlarged section of a sponge, shown by tig, 1, pi. i, and fig. 3, l»L iv, the growth has been a combination of the regular double walls with vertical septa and the vesiculose structure shown by fig. Id, pi. i. The septa exist between several different, more or less entire, inner walls, and the thin arched dissepiments crow itself is filled witli light colored liujcstone, rendering it easily distinguishable from the interseptal areas, which are filled with a darker colored material. These latter appear to have been twenty-eight in number. The radiating septa may be ob- (813) m ..'Hfj 'm\; j'.flj '■:''r||i| '(»:/l"W!.i ; :-/"l^' ' ' ■ 'M ■ -m '■'M'' 1 '■ 88 CAMBRIAN FAUNAS OF NORTH AMERICA. [BULL. to. if " served in two or three places, and are seen to be thin and delicate. The outer wall has been almost wholly removed and the portions of it that remain are much weathered. The material ])resented for study consists, therefore, of the solid molds of the iuterseptal spaces, the cup filled with limestone, a small number of the septa, a transverse section of the inner wall, and the impression of a considerable portion of the outer wall. The latter shows that the external surface when perfect was longitudinally furrowed as in ArclKcocyathelhts. In that genus, however, so far as known, there are two rows of pores along each of the furrows, one on either side of the septa, wliereas in the present genus there appears to have been but one, and that placed di- rectly on the line of the septa. The evidence of this consists of rulely circular holes placed at regular intervals along the middle of each ur- row in the cast. These appear to me to argue the existence of funnel- like projections inward of the outer wall at the place of the openings. That they mark the position of orifices leading into the interior appears to me in the highest degree probable. Their position is, however, so remarkable, that I was for a long time unable to understand the mean- ing of them. " On one side of the specimen there are a small number of the iuter- septal molds that project beyond the others, and one of these shows one of its lateral faces for a considerable distance lengthwise, and also nearly down to the outer surface of the inner wall. An examination of this face shows that the cavities observed along the furrows extend but a short distance inward, and that the septa arched around the funnel- like projections which they represent from below, striking the outer wall only at the intervening spaces. * * * * * It is further shown that these cavities are directed slightly upward, or toward the aperture of the cup. These characters serve to distinguish the form at once from ArchcBocyathellus, in which the septa meet the outer wall un- interruptedly. "If I am right in viewing the cavities along the furrows in the cast as indicating the presence of external orifices at these points, then it follows that these orifices were doubtless functionally equivalent to the double row of orifices along the furrows of the outer wall of Archavcy athellus. In proof of this it may be remarked that the size of the cavi- ties indicates that the orifices were, proportionally, considerably larger than those of the only known species of Archceocyathellm {A, Rennse- laericus), while their position is such as to present no obstacle in the way of regarding them as having communicated simultaneously with two of the iuterseptal spaces." As stated under the generic description, the proposed genus Proto- cyathus does not appear to be well established. The difference given, the occurrence of a single row of large pores over the septum which is (814^ WAI.0OTT.1 MIDDLE CAMBRIAN FAUNA. 89 based on the inner cast of the outer wall, is not, so it appears to nie, of generic value. The same structure is shown in fig. 2 of pi. v, a sj)eciineu that 1 doubtfully refer to this species in preference to JU. h'em- selaericum; the reason for this is shown by fig. 2, i»l. iv, the holes being tlie openings through the septa connecting the intcrseptal spaces; the outer wall having been removed in figs. 2, 2ft, of pi. v. We shall await further evidence before accepting the genus Protocyathus. Formation and locality. — Middle Cambrian. Conglomerate limestone, ou the ridge east of the city of Troy, New York. Genus LEPTOMITUS n. gen. , LeptoH (fine), niitoH (thread). Elongate bodies, formed of line thread-like longitudinal lines (?) ap- parently imbedded in a delicate membrane (?), slowly expanding from a narrow base. The appearance of these bodies is such as might be formed by the tuft of long silicious spicules of the glass-rope sponge, Ilyalonema, if the latter were pressed out between the layers of the shale and the ani- mal matter formed a film about the fine, delicate, thread-like spiculae. In the type specimen a confused mass of spiculfc (1), crossing each other at right angles, occurs at the larger end. Type Leptomitus Zitteli. i> : I; ■'1^! ^ifi rHi liWv Mh ^■km " m M ' 1 !|| •ii^jv- Leptomitus Zitteli u. sp. ler the at un- ;ast ■n it tlie •ocy avi- g(M' IHSC- Plate ii, figs. 2, 2a. Several fragments of this form were found in the fine-grained argil- lites at Parker's quarry in association with Olenellvs Thompsoni, Prot»- caris Marshi, &(i. The resemblance to a bundle of the elongsite spicule of Hyalonema is very striking, and the occurrence of the confused and broken spicules at the larger end of the best preserved specimen, and the crossing of the lines or striae and their breaking up into several parts at the opi)08ite end, give added force to the coini)arison. Although we have no proof that the sharp raised lines were slender silicious spicules, there is little doubt in my mind that in this form we have a representative of Hyalonema in the Middle Cambrian. My first impression was that the species was related to Serpulitcs dis- solutns Billings, of the Trenton limestone, but an examination with a uiagnifying glass at once dispelled the idea and caused a reference to tlie SpongisB. Formation and locality. — Middle Cambrian, Georgia Formation. Parker's quarry, Georgia, Franklin County, Vermont. (816) m ,1, . i' ill : ^ k -if w ■ ]fii \fi m ^ y 90 CAMBKIAN FAUNAH OF NORTH AMERICA. iBUtuaa Genus PKOTOSPONGIA Salter. Protospongia Salter, 1864. Quart. Jour. Geo). Soc, vol. xx, p. 238, pi. xiii. Peotospongia fenestbata Salter. Plate vi. fig8. 2, 2a-b. Protospongia fenestra ta SahcT, 1HG4. Quart. Jour. Geol. Soc, vol. xx,p. 2;{8, pi. xiii,fig. 12o-6. iWd, Cat. Cumbrian and Silurian Fossils, p. :<, 1H7H. Hicks, 1H74. Quart. Jour. Gool. Soc, vol. xxvii, p. 401, pi. xvi, fig. 80. Zittel, 1877. Abli. derk. Imyer. Akadeniie der Wiss., "2. L'l., xiii. Bd. "Studiin ii. Fossile Spongicn " (p. 4.'), s«p. copy). Carter. 1877. Ann. and Mag. Nat. Hist., ser. 4, vol. xxv, p. 177. Brogger, 1878. On» paradoxidesskifrene ved Krekling. Separataftryk af Nyt Magazin for Naturvidensk., vol. xxiv, i,p. 20, t. 6, f. 14.. Sollas, 1880. Quart. Jour. Geol. Soc, vol. xxxvi.p. :162, figs. 1,2. Roomer, 18H0. l^ethea Geogu., 1. Th., p. 316, f. 59. Hiude, 1883. Cat. Fossil Spongps, p. 129, pi. xxviii, fig. 2. Walcott, 1884. Monographs U. S. Geol. Survey, vol. viii, p. 11, pi. ix, figs. 5, rya, b. Mr. Salter originally described tlii.s interesting sponge as having a loosely reticulate skeleton formed of very large cruciform spiculai, the branches of which cross each other at an angle of 80°, and only iu one plane, no ascending or descending branches rising from the point of conjunction. The angles occasionally vary, but not much. More perfect specimens obtained by Dr. Hicks show the spiculae to be quadriradiate, slightly raised at the center, and formed of four nearly cylindrical rays. The skeleton, as described by Mr. Sollas, is composed of large primary ppiculae, with the interspaces filled in by three series of spiculae, each formed of spiculae smaller than those preceding it, their rays all lying regularly disposed iu two directions at right angles to each other, and so building up a net-work with square meshes. The skeleton is not preserved in any of the Nevada specimens, the dift'erent sized spicnilae lying scattered on the surface of the limestone shale or crowded together w ithout any regularity in the direction of the rays or the size of the spiculae. The spiculae, however, appear to be identical in all respects with those described by Messrs. Salter, Hicks, and Sollas, and if they had not been scattered or crow •> ^^. ^ ^^? '/ Photographic Sciences Corporation 23 WfeST MAIN STREET WEBSTER, NY. MS80 (716) 872-4503 ) 92 CAMBRIAN FAUNAS OF NOBTH AMERICA. [BVLUM. In a letter written to Prof. Jules Marcou, December 28, 1860, Mr. Emmons states "that most if not all those beautiful graptolites referml fo the Hudson Biver Group by Prof. T. Hall belong to the Taconiv. There are probably two species in the Trenton and the slates above. No more." (Proc. Amer. Acad. Arts and 8ci., new ser., vol. xii, 1885, p. 188.) This proves that Mr. Emmons had not a clear idea of the por- tion uf the shales of the Hudson Biver Valley that contain the grapto lites described by Prof Hall, nor of the shales at Point Levis carrying the graptolitic fauna. Elsewhere in Vermont, Virginia, and Tennessee he did not distinguish between the older rocks and those of the Hudson Biver Formation. Of this we will speak at another place and time. Prof. Hall described Chraptolithtis Milesi (Geology of Vermont, vol. i, 1861, p. 372) as from a bowlder of Georgia slate picked up in the town of Monkton, Vermont. The species is of the type of those from Point Levis, and as nothing of the kind has yet been found in situ in the Georgia shales, and the bowlder was found on the line of the glacial drift from Canada, I do not think it best under the circumstances to admit the species to the Georgia fauna. Prof. Hall thinks that " it is proba- bly of the Quebec Group." (Can. Org. Bemains, Dec. II, p. 63.) On plate i of his American Geology, Prof. Emmons figures two species of graptolites, fig. 11 as Diplograptus s&Mlinm and fig. 2 as an unde- termined species. At Swanton Falls, Vermont, a species of graptolite occurs in the shales that is identical with Climacograptua bioornis of the Hudson Bivei- Formation. I rof. Marcou refers the strata containing the graptolites to the Taoonic, and places it below the I otsdam sandstone, but I think without either stratigraphic or paleontologic evidence. Genus DIPLOGBAPTUS McCoy. Diplograptus ? simplex Emmons. Plato xi, figs. 4, 4a. Diplograptu9 simplex Eionions, 1855. Auier. 6eoI.,voI. i.pt. 2, p. 104, pi. i, tig. Vi. Original description. — *' Straight ; serrations pointed, cells, rather dis tant oblique to the axis; the serration equal in length to one-sixth or one-seventh of the width of the stem. The u,>per or young part of the stem is three-eighths of an inch wide and the number of serrations is 24 to an inch. It narrows towards the base, where the serrations iiro rather obtuse and more distant than those above, and is 10 inches long as exposed upon the slate. It is confined to the Hoosic rooting slate." Dr. Emmons originally applied the name Fucoiden simplex (Tnconic System, 1844, pi. v, fig. 1 ; Agric. Kept. N. Y., pt. 6, 1846, pi. xvii, fiji- 1) to a species previously named by Prof. Amos Eaton (see Twentieth Kept. N. Y. State Mas. Nat. Hist, 1868, p. 268) as Fucoides secalinm. Sal)- (818) WAtoorr.] MIDOLG CAMBRIAN FAUNA. 93 seqiiently be referred the species named by him to Eaton's F. seealinuSf calling it JMplogmptus aecalinuSy gave a description as above, and at the same time figured another species which we have tbund in the fine ar- gillaceous shales of Parker's ledge. For this I have decided to use Emmons's name aimplexj the name D. secalinus being restricted to the species from the Hudson Biver Group, as described by Prof. Hall (Pal. N. Y., vol. i, 1847, p. 267). The specimens from Vermont are completely flattened in the shale, and are small as compared with the stipes described by Dr. Emmons, as the largest one is scarcely 2 inches in length and the small ones have much the same appearance as the compressed frond of a Phyllograptns, but the similarity between the figure given in his American Geology and tlie central portion of the longer fronds from Vermont is so marked that I think they are identical. Dr. Emmons states that the known locality was in the Hoosic slate, but I suspect, from his having worked to the north in Washington County, New York, he may have procured the spec- imen figured from some other place, referring the slate to the same geo- logic age as that at Hoosic ; this is the more probable, as a similar con- fusion of localities is to be detected in other parts of his work. The details of the description are drawn apparently from the small speci- men figured, rather than from the distorted specimens usually observed ill the Hoosic slate. In several of the Vermont specimens there is a Htrong, round, central axis, as shown in fig. 4 of plate xi, that appears 08 though a hollow axis had been filled with sediment in a more or less complete manner, thus preserving the form of the axis, while in other specimens it was compressed and all traces of it lost. Formation and locality. — Middle Cambrian, Georgia Formation. Par- ker's quarry, Georgia, Franklin County, Vermont. Genus CLIMACOGRAPTUS Hall. Climaoograptus f ? Emmonsi n. sp. Plate xi, fig. 5. The only specimen we have of this species is the upper portion of a single stipe found by Mr. E. Hurlburt in the same band of shale with Diplograptua f simplex, Meaonacis Vermontana, Olenellua Thompaoni, and Protocaria Marahi. The stipe is elongate, narrow, and with narrow, deep indentations on each side, at right angles to the axis of the stipe, that reach well in towards the center, leaving short, strong pinnulalike projections be- tween them that alternate, with relation to each other, on the opposite sides of the stipe. Where the stipe is 4"'" broad, ten indentations occur in a distance of 11""". The position and character of the cellules are unknown ; whether they are in the deep indentations, and the speci- men shows the lateral view of a compressed stipe, as in Climaoograp- (819) ■ i; I II ^1 ' iC 94 CAMBHiAN FAUNAS OF NORTH AMERICA tBULL.90. tns when similarly compressed, or whether they form the rather large projecting points between the indentations, somewhat as in Rastrites, is not determined. The reference to Glimacograptns is entirely provis ional, and not intended to indicate the presence of that genus in the Georgia Formation, but that v form too imperfect for a close generic reference, resembling compressed specimens of Climacograptns, occurs at that horizon. Sooner or later more extensive collections will be made in the Georgia shales, and it may be that the gi'aptolitio fauna will be more fully de- veloped. The specimen figured by Dr. Emmons as ^intermediate species" (Amer. Geol., pi. i, fig. 2) appears to be the same as the specimen under consideration. No description or reference to locality is given by Dr. Emmons. The specific name is given in memory of Dr. E. Emmons, who strag- gled so long to maintain the pre-Potsdam age of the formation in which this graptolite occnrs. For the use of the specimen I am indebted to Mr. E. Burlbnrt, of Utica, New York. Formation and locality. — Middle Cambrian, Georgia formation. Park- er's quarry, Franklin County, Vermont. BCHINOZmRMATA. Genus EOCYSTITES BilUngs. Eoe^Hlet BillingB, 1668. Acadian Geology, p. 643, fig. 220. EOOYSTITES f t LONGIDAOTYLUS n. Sp. Plate y, fig. 3 ; pi. vi, figs. 1, lo-o. €leneral form elongate-oval or ovate, as far as can be determined from the crushed specimens. Plates numerous, disposed without apparent order and varying in form, size, and surface characters on the same body. The margin of many of the plates appears to be indented so as to leave an opening, or pore, that passed into the central cavity; these plates are grouped together on one side, so far as we now know. The surface of the plates varies: (1) smooth and nearly flat; (2) smooth and slightly elevated at the center ; (3) smooth and depressed at the center, with more or less distinct ridges radiating out to the margin; (4) more or less prominent ridges radiating out from the center to the margin. The plates of type 4 have crenulations on the margin that give rise to an appearance of the presence of pores. None of the opeuiDgs of the body has yet been observed. A row of long slender arms appears to have surrounded the summit. Unfortunately our specimens do not show the summit distinctly, nor the (820) m& WALOOTT.] MIDDLE CAMBRIAN FAUNA. 96 arrangement of the arms about it, although, in the speciraens repre- seoted by figure 16, the bases of several arms are present on what ap- liears to be the inner side of the summit of the body. The arms are formed of two series of plates that slightly alternate in relation to each other, as shown in fig. lb. Oasts of short piuuulsB are seen along the side of several of the arms — a pinnule to each plate on the side at which it occurs. None of the arms show an ambulacral groove. St«m or pedicle unknown. The specimens collected are from a pinkish argillaceous shale and have been injured by distortion and compression. Plates of the same general type were found 1,000 feet lower in the strata in the Ely Mount* aius associated with Olenellua Gilberti ; also, it Parker's quarry, Georgia, Yt., associated with Olenelltu Thompsoni^ Olenoides Mareouij Protypui Henectus, &c. The reference of this species to the genus Eocystites is entirely pro- visional, as the genus was founded on loose plates of a cystid found in the St. John Formation of the Lower Cambrian System. The St. John Formation plates are more strongly ridged than those of E.f t longidactyltUy but I know no way of generically distinguishing them, or either of these, from the plates described as Protocystites Menevensi» Hicks (Quart Jour. Geol. Soc., vol. xxviii, p. 180, pi. v, fig. 19). Under the circumstances I prefer to wait until more is known of the described genera before definitely expressing an opinion on the generic relations of P. t f longidaotylus. Troohocystitea Bohemicua Barrande (Bull. Soc. G^ol. de France, 2* s^r., t. xvii, p. 537, pi. viii, fig. 1) appears to be distinct &om both Eocystites and Protocystites. Formation and locaUties. — Middle Cambrian. Chisholm mine, south- west slope of the Ely Mountains near Pioche ; also, in the Highland range, eleven miles north of Bennet's Spring, Nevada, associated with Olenoides typicaliSj Bathyuriacm produetUj Ptychoparia PtooAenm, &o. iv BRACHIOPODA. Genus LINGULELLA Salter. UnguUlla Salter, 1861. Memoirs Geol. Surv. 6t. Brit., p. 333. LiNOULELLA G^LATA Hall (sp.). Plate vii, figs. 1, la-i. Orbioula oalata Hall, 1847. Pal. N. Y., vol. i, p. 290, pi. Ixxix, figs. 9a-c. UlioUUa (0.) oalata Ford, 1871. Ainer. Joar. Sci., 3d ser., vol. ii, p. 33. LinguMla calala Ford, 1878. Amer. Jour. Soi., 3d ser., vol. xv, p. 127. Original deeoripiion. — *< Orbicular, small; apex excentrio, depressed along the center, and subplicated near the margins ; surface marked by (821) m 96 CAMBRIAN FAUNAS OF NOBTR AMERICA. [nULi.. 30. fine coiioentric lines and miiinte elevated points, giving it the appear, anoe of being covered by a poriferous coral/' Mr. Ford subsequently studied the species and described it as fol- lows : '< The ventral valve is somewhat elongate-ovate, with the beak pointed, slightly elevated, and conspicuously channeled for the passage of the iiedicle. The convexity is moderate and nearly uniform. On the inside there are two prominent, elongate, curved scars, one on either side of the median line, with their concavities directed outward. These recall by their form and position the large lateral scars of the ventral ■valve of certain species of Obolella (e. g., 0. ohromatica). The otiier impressions of this valve have not been made out. *' The dorsal valve is more rotund than the ventral and has the heak much depressed. The convexity increases with increasing age, and in adult specimens is such as to sometimes give the valve a semi-globoae appearance. A shallow depression extends in all the specimens from the beak to the front margin, but in fully grown forms it is often incon- spicuous. On the inside there are four prominent ridges. Of these the more central two commence close to the median line a short distance in front of the beak and extend into the forward third of the shell slightly diverging throughout, while the lateral pair take tlieir rise close to the beak and reach to points a little in advance of the raid-length. There is also a short, slender ridge directly beneath the beak, on the median line. The central portion of the valve in the upper half is slightly ex- cavated. The description of the interior of titis valve has been mainly drawn up from an excellent natural internal mold. "The surface of both valves is ornamented with moderately conspicn- ous radiating and concentric lines, the latter irregularly grouped, and covering the whole a fine papillose network, the points of which are ar- ranged in concentric series, those of one series alternating with those of the next, and so on, as first pointed out by Professor Hall in his description of the dorsal valve. (Pal. N. Y., vol. i, p. 290, pi. V9, fig. 9.) The effect of this style of ornamentation is very beautiful, and when, as is usually the case, the shells have a dark, polished aspect, with a setting of liglit- colored limestone, few handsomer fossil objects can be named. The shell is thick and of a finely lamellar structure. The usual length of the ventral valve is about three and one-half lines." To Mr. Ford's description we may add that the interior of the shell shows rather large punctie or small pits, as in the type of the genus Lingulella Davisii. There is also considerable variation in the strength and character of the papillose surface. In some small shells it is very diffi- cult to detect it at all, and in others the arrangement of the papillte is so broken by the fine, wavy concentric lines and stronger, radiating, undu- lating lines that the surface appears more like that of some species of the genus Kutorgina than that of the typical species of Lingulella. (822) mvccfiT.] MIDDLE CAMBRIAN FAUNA. 97 Formation and locality. — Middle Cambrian, Georgia Formation. Con- glomerate limestoue on the ridge east of tlie city of Troy, N. Y.; also, cue mile Bouth of Scliodack Lauding, in Columbia County, New York. LlNGULELLA EllA H. & W. Plate vii, fig. S; pi. viii, fig. 4, 4a-«. LinguUpia Ella Hall & Whitiiflld, 1877. Oeol. Ezpl. Fortieth Par., vol. iv, p. 233, pi. i, flg. 8. Original description. — *< Shell below tlie medium size. Dorsal valve subcircalar or oblate, the width slightly exceeding the length ; the beak perceptibly projecting beyond the general contour of the shell, but very obtuse and slightly truncate ; sides and base rounded, the latter more broadly curved. Surface of the valve depressed-convex, a little the most prominent on the umbone ; marked by line, irregular, concentric lines of growth on the upper part, becoming more strongly marked and finally quite lamellose toward the margin of the valve. A few very indistinct, radiating lines may be seen near the beak by the aid of a strong magnifier. Ventral valve unknown. Shell-substance phos- phatic. "There may be some doubt as to the true relations of this shell. The broadly oblate form would be an objection to considering it as a true Lingula, while the truncation of the beak of the dorsal valve would accord more nearly with what is known of some forms of Lingulepis. It is possible it may prove to be Lingulella, but in the absence of the ventral valve it cannot be satisfactorily determined. It diifers from most known species very perceptibly in the oblate form of the valve. ^^ Formation and locality. — In greenish argillaceous shales of the age of the Quebec group, in the canon above Call's Fort, north of Box Elder Cafioh, Wasatch Range, Utah. Collected by S. F. Emmons, esq." The reference of the species to the Quebec Formation is incorrect, as it occurs with a characteristic Middle Cambrian fauna, 2,000 feet below the Potsdam horizon of the Upper Cambrian. More perfect specimens of the dorsal valve show the surface charac- ters, and also show that the beak is slightly more projecting. The ventral valve is longer than wide ; angle formed by the cardinal slopes about 65° in uncompressed specimens and 90° to 120° in flat- toued, compressed specimens; sides arching to the broadly rounded frontal margin ; area flattened, rather broad, and with a narrow median groove. The cast of an interior of a dorsal ? valve from the Oquirrh Range shows two long lateral scars gradually diverging from near the beak, also a central median depression with two posterior adductor sc^ -'s, and the anterior adductor scars near the terminus. The system of scars, so far as preserved, is much like the dorsal valve of Obolella erawa. (See pi. x, flg. le. Compare also with Lingula, Monographs United States Geological Survey, vol. viii, plate xxi, figs. 18-20.) Bull. 30 7 (823) ^ If 15 iii m - 1 98 CAMBRIAN FAUNAS Oy NORTH AMERICA. iBULu sa Surface marked by fine concontric lineH of growth, and on Home n)mAh fine radiating lines are seen near the beak ; when the surface is entire a secondary system of ornamentation is seen as very fine concentric strite, broken by very short undulations that give almost a reticulated surface. The Wasatch specimens show valves 2""" to 9'"'" in length. Those firom near Pioche are more compressed and appear more quadrangular and broader than the Waibatch forms, except in the small shells, which are very much alike. When the dorsal valves are compressed longitud- inally, the cardinal line is straightened and the concent lic stria; are depressed, so that the shell might readily be taken for a species of Ku- torgina. Figures 4& and 4c, pi. viii, are drawn from casts of the interior of the two valves as they occur in the shales of the Highland Bange and at the Ghisholm mine, near Pioche. Figure 4(2 shows the relative propor tions of the valves to each other when flattened in the shale. Formation and localities. — Middle Cambrian. Box Elder Gaiion, above Call's Fort; Big Cottonwood Canon, one mile below Argenta, Wasatch Mountains; East Cafion, above Ophir City, Oquirrh Mountains, Utah, in dark silicious argillites ; also, in the pinkish argillaceous shale at the Ghisholm mine, southwest face of the Ely Mountains, near Pioche, Nevada. Genus ACROTEETA Kutorga. Aorotreta Kutorga, 1848. Yerhandl. der rnHsisch. kais. niin. Qesellsch., St. Petera- bnrg, 1847, p. 275. Type A. mhconica, same report, p. 275, pi. vii, flgs. 7a-c. AoBOiRBTA GEMMA Billings. Plate viii, flgs. 1, la, h. Aorotreta gemma Billings, 1865. Paleozoic fossils, vol. i, p. 218, figs. 201a-/. Aorotreta tuhconica and A, Aitenuata Meek, 1873. Sixth Ann. Rep, U. S. Geol. Surv. TeiT., p. 463. Aorotreta pyxidicula White, 1874. Geog. and Geol. Expl. and Siirv. West 100th Merid., Rep. Invert. Poss., p. 9; vol. iv, pt. 1, p. 53, pi. iii, tigs. 3o-d, 1875. Aorotreta gemma Walcott, 1884. Moiigraphs U. S. Geol. Survey, vol. viii, Pal. Eureka diatrict, p. 17, pi. i, figs, la, 16, \d, \f; pl.ix, figs. 9,9a. Original description. — "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 angnlated at the beak, on each side of which a portion of the cardinal edge, equal to onc-lourth 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 (824) WALOorr.] MIDDLE CAMBRIAN FAUNA. 99 sinuH extends from the front niargiu about balf wuy to the beak;eUe- where the valve is gently convex or nearly tlat. "Ventral valve acutely conical, with a flat triangular area which iti IM^rpeudicular to the plane of the lateral margin, its base half the widtli 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 forumiual 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 one lino: length, about I'ight-itintlis of a line. The height ot the ventral valve is about one line. "The form of this species is very like that of A. nuhconica (Kutorga), but that species is twice the size of this and has the area distinctly grooved." The groove on the aree, of which Mr. Billings speaks, is variable; in some specimens it can be scarcely determined and in others it is quite distinct. As far as the size is concerned, we have specimens from 2'"°> in diameter up to 5°"". The variation in the height of the ventral valve is also considerable. The relations of the species to Acrotreta suhconica Kutorga (Cber die Bracbiopoden-Familie der Siphonotretsese. Yerhandl. der russisch. kais. min. Gesellschaft, 1848, p. 275, pi. vii, flgs. 7a-c) are strong, and, except the greater elevation of the ventral valve, there are no marked differences. Without a direct comparison of specimens, I do not think it best to identify the American form with the Russian, although, from its having such a great geologic range, it was probably widely distrib- uted in the Cambrian seas. In the Paleontology of the Eureka District, pages 17 and 18, I Imve giren the range of this species as then known. We now have to add that it occurs at a horizon 4,000 feet below the lowest horizon there and is associated with species of Olenellus just above the great series of Cambrian quartzites. The shell is more robust and larger than the average specimens of the Upper Cambrian, but specimens fi'om the Upper Cambrian beds on the Gallatin Biver are nearly as large, and the form of the exterior of the valves and their interior muscular markings are essentially the same ; the differences are so slight that I do not hesi- tate to place them under one species. More favorable conditions of habitat and food would produce the variation in size; also, the change liable to occur in a species living through so long a period of time as the .accumulation of 3,000 feet of limestone would require. The associated species are Kutorgina pannula, Acrothele aubaiduaj Or- thisina sp. f , and trilobitic remains. Formation and locality. — Middle Cambrian. East side of anticlinal, in limestone just above quartzite, Pioche, Nevada. (825) 100 CAMBBIAN FAUNAS OF NOUTH AMEBICA. limx.M, Genus IPHIDEA Billings. IphUm BilUngs, 1874. Cau. Nat., new Mr., vol. vi, p. 477. IPHIDEA BELLA BilUngS. Plate vii, fig. 4. li>kMra kfllla Billings, 1872. Can. Nat., new ser., vol. vl, p. 477. Idem, 1B74. Pal.Foaa. vol. ii, pt. 1, p. 76. The descriptions of the genns Iphidea and the type species I. bella were united in the following: Original description. — *< Of this genuH we have no H])eciuien8 showing the internal structure, but the external characters seem sufficient to Hep- arate it from any described generic group. The ventral f valve of /. hella is conical, strongly elevated at the beak, hinge line nearly straight, posterior angles narrowly rounded, sides and front nearly uuiforatly rounded, forming rather more than a semicircle. PoHterior side with a large false area and a convex pseudo-deltidiuni, 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, most elevateht. They may be called laterals. They are, in general, separated from each other about one-third of the width of the shell. A little above the mid length, and l)etween the two laterals, there is a pair of small scars arranged transversely, with their inner extremities directed somewhat forward, Tlu? space above these two scars, between the upper portion of the laterals, is generally tumid from the thickening of the shell. In one of the specimens there is a small i)it in the center of this space. " The dorsal valve has a small area, or nearly ihit Iniige facet. The minute beak is slightly incurved over rhe edge of the area. Beneath the beak there is a small subangular ridge, on each side of which there is a cardinal ? scar. The elongated scars, which seen) to conespond to the laterals of the ventral valve, are here altogether in the upper half of tlie shell. They diverge widely in their extension forward. They are in general very slightly im|)ressed, and would, most probably, esj^ape the observation of any one who did not expe<'t to tind scars where they are situated. In thet cavity of the valve there is a low rounde2, pi. Ixxx, figs. 3a, h. OholeUa (Orhiculii f) vrnnHU Fold, IH7I. Aim^r. Jour. Sci., IM «er., vol. ii, p. WW, Obolvlla uruvna, O. dvHiiuamala Hilling.s, 18T1. (Jan. Nat., now 8cr., vol. vi, p. 218. Idem, 1870. AiiHT. .lour. Sci., :!d wsr., vol. iii, p. :!."»(). DUellomuH crmnn Hall, 1873. Twonty-tbird Kt^p. N. Y. StatoCali. Nat. Hi8t.,p. a4(i, pi. xiii.HgH. (5-0. Obolella vraiwa Ford, 1881. Amur. .Joiir. Sci., 3d Hur., vol. xxi, p. 131, figs. 1,2. Tbe ori$;iiial (le.s(5ription of tlie species appears to be that of the ex- terior of the veutial valve, aud i.s as follow.s: 'M^vat-eorbicular, with the apex near the narrow extremity; apex obtu.se; surface marked by strong concentric wrinkles and fine rtuliatiug strise. "These characters are preserved in the cast, a small portion only of the shell remaining upon the specimen. ^^ Position and locality. — This species was found in the intercalated calcareous strata, among the shales of the Hudson Eiver group, two miles northeast of Troy." Mr. Billings, in J8U1 (Geol. Vermont, vol. ii, p. 947), thought that Aviculaf desquainata Uall might be referreortioii of the valve is niarkeortionof the valvo there is a pair of still larjfer impressions,' bavin*; their upper portions parallel and their lower, falcate i)arts widely diver;;iu},'. r»etween their parallel portions there is a low mesial rid^e, which dies()ut before reacli- iUK the liin;;e line. The falciform i>orlions of these H<'ars are, in {general, very faintly impressed, an■ rt-C. Obolella f/emma Billiiifj.s, 187'^. Can. N.at., new sor., vol. vi,p. 218, fi(f. ."), of p. 217. Original ileHcription. — •' Shell very small, about two or three lines in length, ovate, both valves moderately convex and nearly smooth. Vent- ral valve ovate, the anterior margin broadly rounded, with sometimes a portion in the middle nearly straight ; greatest width at about one-third the length from the front, thence tapering with gently (!onvex or nearly straight sides to the beak, which is acutely rounded. The area is about one-fifth or one-sixth the whole length of the shell, with a comparatively deep groove, which extends to the apex of the beak. The dorsal valve ' ccin.Drif^inal. (842) WAirOTT.l MIDDLE rAMHRIAN FAUNA. 117 JH ri(>iirly (HnMilar, ohscurcly iin;;iiliii- at tlu; lunik, iiiid riitiuM- iiiorv Itioiully roiiiulcd iit tlic IVoiit iiiiii';;iti tliiui nt Mic .sido.s. "Ill (lie iiitcrioi' of tlif vcntnil valve t here are two siiiiill intiseiiiar iiiipn'MHJoiiK of a Innate form, close to the eanlitial inat'<;iii, one on each Hide of the median line. A second pair consists of two elongate snb- linear scars, \vhi(!li extend from the posterior third of the length <»f thei sliell to ]>oints situated at ahont oiie-fonrth the len^fth from the front inat'^'in. Tlies*^ sears are nearly straight, parallel or slightly diver;riii^ forwards, unecinieii is the obscure character of the elongate lateral scars. The shell also shows radiating lines that appear to have been color lines in the original shell. Specimens from I>ic Harbor show the various features seen in the Troy specimens, but not in as perfect a con- dition in any one specimen. 1 do not think there is much doubt of the identity of the shells found at Troy with those from Bic Harbor. Formation and localities. — Middle Cambrian. In the conglomerate limostonea of St. Simon and Bic Harbor, on the St. Lawrence River, below Quebec, Canada. Mr. Ford discovered the species on the ri. 213. Original dcfieription. — "Shell transversely suboval, small. Dorsal valve gently but irregularly convex, the greatest elevation occurring at a point about one fifth the length of the valve froni the apex. From this ]>oint the licak curves sharply down to the hinge line, which it almost touches. The hinge line itself is slightly curved and apparently equal to about one-third the width of the shell. At the most elevated l)oiut of the valve commences a well-defiueu mediuu depression, which (844) WAI.C( exte gra( l)ort alia oftl we t WAIXOTT.) MIDDLE CAMBRIAN FAUNA. 119 extends forward for a distance of about one-half the length of the valve, gradually widening and becoming more shallow till it disappears. A ])ortion of the don il valve close to the margin is sometimes nearly flat all around. The internal markings are not well enough shown in any of the specimens that I have seen to admit of description. The surface is '^T'uamented with very fine concentric striae and na'uerous close-set rauiating striae, the whole just visible to the unassisted eye. "The ventral valve is not certainly known. The width of the largest dorsal valve that I havs seen is 0.14 of an inch and the letigth O.IO of an inch." The above description and the figure of a type specimen are all that we have of the species. Formation and locality. — Middle Cambrian. Even-bedded and con- glomerate limestones on the ridge east of the city '^f Troy, New York. Genus ORTHIS Dalmsa. OHlm Dalumu, 1827. See Brit. Fo88. Bracli., vol. i ; Geul. Introductioa, p. 101. OETHIS ? HiGHLANDENSIS U. Sp. Plato viii, ligs. :?, 3a, 6. Shell about the average size of the Cambrian species, but below the size of those from the Silurian. Transversely oval or subrotund, front broadly rounded and nearly straight in the dorsal valve ; hinge line shorter than the greatest v idth of the shell. Ventral valve moderately convex, most elevated toward the beak, which is slightly arched over to meet the nearly perpendic ular area : mesial sinus broad and shallow or nearly obsolete; areailat; foramen unknown. Dorsal valve associated in the same hard specimens of limestone, more convex than the ventral valve ; hinge line ver^, short, median fold but slightly raised above the general surface ; area unknown. Surface marked by concentric lines of growth and finer striae. No traces of radiating costae are seen except on the interior of the shell towards the margin. Casts of the interior of the ventral valve show the dental plates, median ridge and bifurcating ridges extending nearly to the margin; also, two lateral grooves. Tlu> specimens of the interior of the dorsal valve show only faint Impressions of a large oval soar each side of the median line. The form of the dental plates, the prolonged ridges, and the short median ridge of the ventral valve associate this species with Orthis rather than Orthisina. The interior of the ventral valve alHes it closer to 0. Pepina Hall (Sixteenth Ann. Rep. K. Y. State (Jab. Nat. Hist., p. l'{4,i)l. vi, figs. 23-27) of the Wisconsin and Texas Upper Cambrian (Pots- dam) horizon than to the species of the Middle Cambrian, unless it be Ortlmiua f Orientalis. It is to be regretted that we have not better material for the study of this and the species placed under Orthisina. (845) ■fflw 120 CAMBRIAN FAUNAS OF NORTH AMERICA. |BUU,. 80. Formation and localities. — Middle Cambriau. In the limestono with OlenelluH Gilbert!, Olcnoides let-is, &c., at Pioche, and also on the west 8ido of the Highland Range, 11 miles north of Bonnet's Springs, and at the south end of the Tinipalmte Range, Grooiue District, Nevada. '"O't Genus ORTHI8INA D'Orbigny. Orthisinn D'Orbiguy, 1841). See Brit. Fosb. Brjich., vol. i, Genl. latroduction, p. 104. Orthisina Orientalis Whitfield. Plate vii, fig. 6. Orthisina Oricnialis Whitfield, 1884. Bull. Amer. Mus. Nat. Hist., vol. i, p. 144, pi. xiv, fig. 0. Original description.—''' Shell quadrangular in outline, somewhat higlier than wide, with vertical and sub-parallel lateral margins, and broadly rounded base. Cardinal line rai)idly sloping from the apex to the extremities, which are slightly rounded. Hinge line straight, as long as the greatest width of the shell. O.irdinal area broad and high, divided in the middle by a triangular foramen, which is about as high as wide. Surface of tlie ventral v.alve moderately convex, marked by very fine radiating striiB and also by several concentric lines of growth. Filliug of the rostral cavity and foramen large and prominent. Speci- men, a cast in shale, of the ventral valve only." The specimen described above is flattened in the shale and also ap- parently compiessed laterally. IJnoompressed specimens referred to this species, from intercalated limestone beds ("lentile") in the slialeseast of Swanton, show it to ha\e been moderately convex, and also specifically distinct from O. Pepina of the Potsdam group in W'sconsin and in Texas. Formation and localities. — Middle Cambrian, (ieorgiah'ormation. Sil- ico-argillaceous shales ; Parker's quarry, town v'f Georgia, and in a gray limestone "lentile" two miles east of Swanton, Vermont, at about the same relative geologic horizon. Orthisina festinata Billings, Plato vii, HgH. 7, 7a, h. Orthisina J'rulinula BilliugH, IHtil. Paiiiphlet ; Geology of Vcriiioiit, vol. ii, !». IM'.I, ligs. ;jr)0-:{5>. nirm, 18(5:?. G, 5o. Shell small, transversely subquadrangular in outline, front broadly rounded, angle formed by the union of the cardinal slopes of the ven- tral valv(3 155° to 165^, hinge line straight and as long as the width of tlie shell. Area of the ventral valve of moderate height, bent back lioiii the hinge line, divided by a triangular foramen that is higher than \viil(! 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 rliaii wide, covered by a h "^^t 122 CAMBRIAN FAUNAS OF NORTH AMERICA. Obthisina? (sp. undt.) (BULL. 30. There are two upecies represented by fragmentary material that np pear to be distinct from any described. One occurs east of Highgate Springs, the other at Parker's quarry. Two undescribed species of Orthis or Orthisina, from L'Anse au Loup, on the Straits of Belle Isle, Labrador, that have not yet been described, occur in the collection of the Geological Survey of Canada. 'I Genus CAMARELLA Billings. Ccmarella Billings, 1859. Can. Nat., vol. iv, p. 301. Original deaeription. — "Family RhynchonellidaB; ventral valve, with a small triangular chamber beneath the beak, supported by a short mesial septum as in PentameruH. Dorsal valve, with a single mesial septum and two short lam< llae for the support of the oral appendages, as in Ehynch4)neUa." The type of the genus is C. Volborthi, the description of which follows that of the genus, and, on page 1 43 of The Geology of Canada, 1863, illus trations are given, figs. 77a, b, c. The species referred to the genus from the Middle Cambrian may belong to it, but we have only the general ex ternal resemblance on which to accept the generic reference. The second species mentioned in the list of species is more like Triplesiaprimordialis (Geol. Wis., vol. iv, p. 172, pi. x, tigs. 1 and 2, 1882) than any other species with which I am acquainted. The only specimens now knowu to me of the second species are in the collections of the museum of the Geological Survey of Canada, and have not yet been described. CAMARELLA ANTIQUATA Billings. Plate vii, tig. 8. Camarella aniiquata Billings, 18(31. Pamphlet; Geology of Vermont, vol. ii, p. 949, fig. .?.',n. Idem.imx Geol. Canada, p. 284, fig. a90. Idem, l&X,. Pal. Foss., vol. i, p. 10, tig. 13. Original description. — "Ovate or subcircular, beaks obtusely pointed (as seen ou the cast), both valves moderately or rather strongly con vex. Surface with from eight to ten small rounded ribs which do not reach quite to the beaks. "Some of the specimens .are proportionally more elongated than others. The front margin appears to be always broadly rounded, and the greatest width at about one-fourth the length from the front margin. "Length, from 4 to 0 lines; width, either equal to or a little less thtm the length. " This species resembles G. varians of the Chazy, but is more uumei- ously ribbed." (848) WAICOTT.] MIDDLE CAMBRIAN FAUNA, 123 We have seen but two syeciiiiens of the cast of a single valve of this species aud cannot add to the description given by Mr. Billings. Forinationand locality. — Middle Cambrian, Georgia Formation. About 2 miles east of Swantou, Vermont. LAMELLIBRANCHIATA. Genus FORDILLA Barraude. Fordilla BaTT!im\n,lSiil. Ac6phal6.s. Etudes Loc. et Comp. 8°. Description of pi. 361. The first notice we have of this interesting genus is by Mr. S. W. Ford (Amer. Jour. Sci., 3d ser., vol. vi, p. 130, 1873), who called atten- tion to it under the title of "Bivalve of uncertain class; gen. nov. ?" lie described it as follows : " Shell transversely oblong or suboval in outline, convex, widest pos- teriorly, narrowed at either extremity, with an oblique posterior ridge, and small depressed unibones situated anteriorly, sometimes present- ing an obscurely bi-lobed appearance in front. Dorsal margin nearly straight, ventral margin uniformlj' rounded. In the interior of the left valve, as shown bj' a gutta-percha cast of an impression in stone of this valve, there is a wide and deep furrow with a slightly raised line along tiie middle of it, corresponding to the oblique ridge on the outside ; and a distinctly impressed line ])assing from the lower anterior into the upper posterior i)ortion of the valve, following the curved ventral edge, iroiu which it is sei)arated by a broad flattened border. This line is deeply suidion anteriorly, becomes almost obsolete or discontinuous in passing the oblique internal furrow, beyond which, in the posterior por- tion of the shell, it is less distinct, though clearly shown. Just in front of and above the anterior limit of this line there is a slight conical pro- tuberance. Further than this nothing can be made out, owing f(» the iin])erfection of the material. The shell is thick, with the surface finely striated concentrically. " I have never observed a specimen of this singular little shell vnth the two valves together, but they are frequently found side by side in the same hand specimen of stone. "Length, rarely more than 0.10 of an inch; usual width, about 0.10." Subsequently Mr. Ford sent specimens to M. Barrande, who pro- posed the above generic name and gave several excellent figures, but retrained from publishing a generic and specific description. iMr. Ford remarks before his descri])tion : "Externally they [the sin- fjle valvesj jn-esent something of the ap[»earanceof a small ModivlopsiH. As no uiuloubted lamellibranchiates have, however, been hitherto d. Acadica was a true Ste- notheca? (Amer. Joiir. Sci., 3d ser., vol. xxix, p. 117, 18^5). More re- cently Mr. G. F. Matthew has published a note on S. Acadica, describing the interior, and proposes that it be placed in a subgenus of Stenotheca, "characterized by its subcircular aperture and patelloid form." No name is given for the proposed subgenus (Canadian Eec. Sci., vol. ii, p. 10, 1886.) Stenotheca rugosa Hall (sp.). Plate xii, figs. 1, la-e. Metaptomat rugosa HaM, 1847. Pal. N. Y., vol. i,p. 306, pi. Ixxxiii,fig8. 6a-o. Stenotheca rugosa B'lllinga, 1872. Cau. Nat.,uew ser., vol. vi,p. 479. Stenotheca pauper Billings, 1872. Can. Nat., new ser., vol. vi, p. 479. Original description. — "Elliptical, with the sides straight; apex ele- vated and slightly bent forwards; posterior extremity broader than the ^anterior; surface marked by strong concentric undulations, which in- crease in number on the posterior side. ^^ Position and locality. — In the subcrystalline calcareous beds, asso- ciated with the Hudson Eiver shales, near Troy." The usual outline of the aperture is that of an elongate oval, varying somewhat in proportion and the curvature of the sides, so as to be sub- circular in some examples. The apex varies in position from a point nearly over the anterior margin to one-third the distance between tlie anterior and posterior margins. On a young shell, 3""" in length, the apex overhangs the anterior margin. There is considerable variation in the surface markings; the strong annulations of growth seen on some (854) WALCOTT.I klDDLfi CAMBftfAN PAtFNA. 129 sIu'IIh are reduced in size and incrensrd in numbers in others, iuid in the yonng shellH only the fine striie seen on ;uMi between th(? annuhi- tions on the older shells are seen. The nnnuliitions also vary from evenly-rounded to sharp, almost inibriciitin^' liilf'es. Tin; entire surface is eoveied by very line, somewhat irrcyuUir stria'.. JMmeiisiom. — An average sized speeiinen has a heij^ht of 7""", with a diameter at the ajierture of 10""" and 13""", respinttively. Steriotheea contuvop'm Salter (Quart. .Tour. Geol. Soe., vol. xxiii, pi. vii) is a more erect, conical shell, but presents nlatively the sanie stroiiff concentric undulations and lines that occur on *S'. rvgosa^ although a much smaller shell. The shell figured from the Spanish Cambrian is so closely related to IS. riu/osa that, from the tigures, it is difficult to And si)eciflc distinctions between them. It is rjot specilically named, but placed under the name of (ja]»ulus, luidt. In (lie text the suygestion is made that perhaps it may belong to the gtMius Metoptoma (Bull. Soc. Geol. de France, t. xvli, ]). 531, ])1. viii, tigs, 3, 3rt, h). Sfenotheca acadica Hartt appears to l)e a coiiipresseil shell that, when compared to flattened, comjn'essed specimens of S. nufofia, is generically related to it. On examining the type of Sfenotheca pauper., in tlie collection of the Geological Survey of Canjida, 1 fonnd it to be a lioarselyribbed variety of S. rvgosa, such as occurs both at Troy, New York, and liic JTarbor, Canada. A variety occurs at L'Anse an Loup that has ranch sharper ridges of growth and strong radiating lines, and it is much more ele- vated and conical than the typicral forms of the species found elsewhere, with the exception of a single Iragment from Troy, New York. Formafion and hcalilies. — Cambrian, Georgia group. Conglomerate limestone on the ridge east of the (lity of Troy, New York; Bic liarbor, below Quebec; L'Anse an Loup, on the north side of the Straits of Belle Isle ; and at Topsail Head, Conception Bay, Newfoundland. • .1 StENOTHECA ? ELONOATA Walcott. Plate xii, fig. 4, -la, b. Sicnoiheca cloiigataWtdcott, lt^!?4. Monographs U. S. (ieol. Siirve.v, vol. viii, p. 23, pi. ix, fi}?8. 2, 2a. k Original description. — '' Shell small, elongate, with the ai)ex incurved and depressed nearly to the nnirgin ; laterally compressed so as to form ii, ridge nearly the entire length. Aperture elongate, ovate, somewhat acutely pointed at the end towards which the apex curves, and rounded at the opposite extiemity, the greatest width occurring about two thirds tlie distance from the narrow end. Surface marked by numerous line concentric striio and lines of growth. "The imrrow elongate aperture, depressed apex, and fine lines of growth serve to distinguish this from described species of the genua. Bull. 30 9 (865) ' Mm I. 130 CAMBRIAN FAUNAS OF NORTIT AMERICA. |nui.L. 30. Ah far as yet known the genuH Steuothecu is conflneil to the Oambiiuu fauna." The Nevada specimens correspond so closely with those from L'Anse an Loup that I fail to find good specific characters to distinguish be- twt'tju them. There is a certain irregularity in the form of the aperture that, united with the rounded carina or angular dorsal ridge, suggests a bivalve shell not unlike the young of the common Mytilus edulin, but, Judging from the material at hand, I think it is only a superficial re semblance. Formation and looalitieH. — Cambrian. In the passage beds between the typical Middle Cambrian (Georgia) and Upper Cambrian (Potsdam) faunas, Secret Cafion, Eureka Mining. District, Nevada. At L'Anse* an Loup, on the north side of the Straits of Belle Isle, it is associated with a typical Middle Cambrian fauna that occurs in a hard reddish- colored limestone. Genus PLATYCERAS Conrad. Platjfceraa Conrad, 1840. Ann. Rop. Geol. Surv. New York, p. 205. The genus Capulus Montfort, 1810 (Conch. Sypt., p. 55), appears to include the species under Platyceras, but, until more is known of the American species, we shall follow the example of Hall and Billings, and refer them to Platyceras. Platyceras ""Eimjevum Billings. Plate xii, v 5a. Ptatyceraa primaivutn BiWinga, 1871. Can. Nat., ne. 't., vol.vi, p. 220. Original description. — " Shell minute, consisting of about two whorls, which, as seen from above, are ventricose, but most narrowly rounded at tiie suture ; the inner whorl scarcely elevated above the outer. The under side is not seen in the apecime,;. Diameter, measured from the outer lip across to the opposite side, one line; width of last whorl at the aperture about one-third of a line.'' Tlie Troj' specimens correspond closely to the above description, and, as they are associated with the same species as P. primwvum at Bic, I have little doubt of their specific identity. From the description, tlie Bic specimen showj the right side. A specimen from Troy is nearly free from the matrix, and proves that the dorsum is nearest the right side and that the left side is more ventricose. The surface is also pre- served, and shows fine striiB Jind lines of growth that arch backward over the dorsum, indicating a deep dorsal sinuosity in the peristome; a second series of fine striae cross the striai of growth and form a fine reticulated surface. Dimensions. — Diameter of cross-section of tlve outer volution, 3"""j diameter of aperture, l.Tfl"""' and 2.5"'"'. (85G) WALcorr.] MIDDLE CAMUUIAN FAUNA. 181 riaiyceroH minutimmum Wuhiott (Pum. in advance 32(1 Re]). N. Y. State MiiH. Nat. Hint, 1880), from the Upper Cambrian (PotHdam) liorizon, is a Hmull Hbell related to P. primnvum. It ditferH in liavinp; Htrou^er surface Htrite, a more prominent dorHal ridge, and the whorl lar^fcr and more prouiiueut. Formation and locality, — Middle Cambrian, Georpia grouj). In the conglomerate limestrno on the ridge east of the city of Troy, New York, and at fiic Harbor, below Quebec, on the St. Lawrence liiver, Canada. PTEROPODA. It is with considerable reservation that I place the genera Ilyolithes • and Matthevia under the Pteropoda. The genera Oonnlaria, Ilyoli- tiiellns,Coleoprion, ColeoluH, Hemiceras, Salterella, Pterotheca, Phrag- inotheca, Matthevia, and i)erhaps Palu^nigma form a group that, although representative, in a measure, of the recent Pteropoda, differ in other re- spects so much that it appears as though a division of the Gasteropoda efjuivalent to the Pteropoda might be consistently made to receive them. . , The following families of this group occur in the Paleozoic: Hyolithes. Hyolithollus. flumiceras. Hyolithellidu). i Coleopriou. I Coloolus. I Camurotheca. VDipIotheca. Tentaoalidffi. ConularidsB. SalterollidiB. Matthevidtn. Pterothecidto. 5 Tontaculites. \ tjtyliola. Conularia. Salterella. J Matthevia. I PaliBuigma f f . SPterotheca. Phrajnnotbeca. r n Genus HYOLITHES Eichwald. Unolithea Eiohwald, 1840. Sil. scbicht. Syst. in Elmtl., ]). 97. Thfca Soworby, 1845; Pugiunculua Barraudo, 1847 ; Vaywella d'Orbi^ny, 1850. Mr. Hall gives a history of this genus and a list of American species placed in it (Pal. N. Y., vol. v, pt. 2, pp. 191-195, 1879). Groupe*! oppo site Potsdam sandstone we find H. excellens, a Lower? Cambrian si)eci '•■ from Newfoundland, and the following from the Middle Canibiian, Georgia Formation: H.- Americanus, H. communis, H. Emmonsi, H. iwpar, and H. princeps; and from the Potsdam sandstone, or Upper Oaiiibrian, H.ffibbosus, H. gregarim, and IF. primordiaUs, a total of nine «l)i'cie8 from the Cambrian System. Since that pubhcation a number of species have been described, and (857) 132 CAMBRIAN KAl^NA.S OF NORTH AMERICA. fBtLL. 30. If '. the American species of the geuns Hyolitlies are distributed us follows, those from above the Potsdam sandstone according to their respective authors and those of the Cambrian in part by the writer : ilyolithes (Tbeca) aculcatus Hall, carbonaria Walcott. aclis Hall, triliratus Hall, singulus Hall. Btriatus Hall. ligea Hall, principalis Hall. ^ Lower Carbonifw- ( 0U8. 1 Hamilton Formation. \ Upper IIeld(rl)erg S Formation. centennialiH Barrett Lower Heldcrbcrf; Formation, p^rviasculus Hall Hudson River For- mation. Vannxemi Walcott Lower Silurian ^Or- dovician). gibbosus H. & W. primordialis Hall, (=gregarin8.) Americanus Billings Billiugsi Walcott. communis Billings. var. Emmousi Ford, impar Ford, princeps Billings. Shaleri Walcott. Upper Cambrian. 'Potsdam Sandstone, Middle Cambrian. Georgia Formation. Lower Cambrian. Braintree Argilliti's. Lower Cjvtabrian. Newfoundland. Lower Cambrian. St. Jolin Series. excellens Billings. (Camarotheca) Daniana Matthew, gracilis Matthew. Micmac Matthew. (Diplotheca) Acadica Hartt. rar. obtus.a Matthew. var. crassa Matthew. var. sericoa Matthew. Hyattiana Matthew. rar. caudata Matthew. In the description of tlie speiiies the flattened side, with the ])rq I'ot ing margin, is considered the dorsal side and the rounded side the ven- tral. This is the reverse of that u.sed by Mr. Billings, Profe.ssor Ilnll, and heretofore by the writer; but a comparison with the shells of the recent genus Cleodora shows the projecting side to be thedor.sal. This view was held by Morris and Sowerby in the de.scrii)tiou of the genus Theca,and by Salter in the description of species (Mem. Geol. Surv. (Jieat I>rit., vol. iii). Hyolithes Americanus Hillings. Plate xiii, tigs. 0, Cm-f. Thvva f triattijularis Hall, 1817. Pal. N. Y., vol. i, ]>. 'M'^, pi. Ixxxvii, figs'. Irt-rf Tluva Iriangvlaris Ford, 1H71. Anicr. .lour. Sci., ;id ser., vol. ii, ]>. ',1',]. Uiiolilhen AmcrivatuiK Billings, 1872. Can. Nat., '2(\ ser., vol. vi, j). 211'), tigs. *Ja,/>, p. 2i;t: Amor. .Four. Sei., M ,s(>r., vol. iii, p. '.io'.), ligs. 2a, b. Original ilescription (Hall). — "lUulies of ji slender i)yra'iiidal form, flat behind and rounded at the larger extremity, angular iti front ; small (858) WALCOTT.l MIDDLE CAMBRIAN FAUNA. 133 extremity pointed ; section (aperture?) triangular. The surface shows HO dclined markings, though the outer covering is not preserved in the specimens which I have seen." . ^^r. BilUngii'H description. — "i7. AmericanuH. — Length from twelve to eighteen lines, tapering at the rate of about four lines to the inch. Section triangular, the three sides flat, slightly convex or slightly con- cave, the dorsal [ventral] and lateral e«lges either quite sharp or acutely rounded. Lower [upjjcrj lip rornded, projecting about two lines in full- grown individuals. Surlace flu'^ly striated, the striie curving forwards on the ventral [dorsal] side, and passing ui)wards on the sid«s at nearly a right angle, curve slightly backwards on the dorsum [ventrum]. In a specimen eighteen lines in length the width of the aperture is about six lines and the depth about four, the proportion being slightly variable. ••The operculum has a very well-defined conical ventral [dorsal] limb, the apex of which is situated above the center, or nearer the dorsal iventral] than the ventral [dorsal] side. The dorsal [ventral] limb forms ii Hat margin, and is so situated that when the operculum is in place tlie plane of this flat border must be nearly at right angles to the lon- {fitiulinal axis of the shell. In an operculum six lines wide the heigiit of t lie lower limb to the a;pex of the cone is two and a half lines, and the width of the flat border, wh'ch constitutes the dorsal [ventral] limb, about one line. '•Tliis species occurs at Bic and St. Simon; al^o, at Troy, New York, wlierc it has been found abundantly by Mr. S. W. Ford, of that city. It is Thcva trian(fulariH of Hall (Pal. N. Y., vol. i, p. 313, 1847). As that name was i)reoccupied by a species previously described by Colonel I'oitlock (Geol. Kep. on Londonderry, p. 375, pi. 28 A, figs. 3rt, 3ft, 3c, 1843), it must be changed. It is a very abuiulaut species and varies a good deal.'' The small shell figured on plate xiii, fig. b/, is broader at the aperture tliau the typical form, but flg. 0 is intermediate, and other specimens still more closely unite the two < xtremes. Thic same range of variation is observed in the common, species of the Potsdam sandstone of Wis- consin, //. primordialin. The operculjB of the two si)eciei.* are also of the same type, and when we coajpare the shells oi H. Americnnm, witii a rounded ventral angle, with the specimens ot H. primor alalia. ^ having a hi<;h ventral angle, the two species approach each other quite closely, the latter species being the representative in the tipper Cambrian of V..e forr.i ^pecjes in the Middle Cambrian. There is a considerable range of variation in the anglb .tf divergence of the sides, and also the angles formed by the union of the three sides. TMd species is quite abundant at Troy, aIthou;jh finely-preserved speci- iiieiu- are rare. Formation and localities. — Middle Cambrian. Conglomerate limestoiui oil the ridge east of Troy, New York, and iu a similar formation at Uic and St. Simon, Canada. (859) ■ ^ ■■ .lis II 134 CAMBRIAN FAUNAS OF NORTH AMERICA. [bull. 30. Hyolitiies Billingsi n. sp. Plate xiii, flgs. 1, la-d. SaUcrcUa ohtuaa BillingB, IHtil. Geology of Vermont, vol. ii, p. 955. Idem, 1865. Pal. FoHS., vol. i, p. 18. HyolUheH pr'mordialh 1 Wliito, 1874. Gcog. and Geol. Expl. & Surv. West lOOtb Merid. Pvelim. Rop, Invert. Foss., p. 6, and vol. iv, pt. 1, ]>. 37, pi. i, tigs. .'ia-e. Not 77i(;rrt ohtusa Salter, 186G. Mem. Geol. Surv. Great Britain, vol. iii, p.:i52. Original description. — " From 8i.\ to eight lines in length; diameter at aperture about three lines. The transverse section is always subtrian gular, and in some of the specimens one side appears to be flat like a Theca, and I would refer it to that genus, only that the tube is composed of successive layers. None of the specimens are perfect, but the form is sufficiently different from that of the other two to indicate a distinct species." When breaking up a piece of rock holding Salterella pulchcUa from L'Anse au Loup, I found several specimens of this species corresponding to the above description, and, not being able to separate them iVom typical forms of the genus Hyolithes and as several species have two or three layers of shell, 1 refer the species to that genus. The shell is very thick aud strong in the specimens identified with H. ohtusa from Nevada. The Nevada shell agrees in every respect with those from L'Anse au Loup. The operculum associated with it appears to be identical with that of H. Antericanus, except in the more rounded ventral angle. //. Billingsi appears, in many examples, to be very closely related to tlie smootlier shells of R. Americanus, and I am strongly inclined to con- sider it little more than a variety of that species. It is, in fact, a form intermediate between the latter and R. primordinlis, and, if the throe forms had been found in the same layer of rock, I shouhl be incline d to unite them in one species; but, as they are from widely separated localities and R. primordialis associated with a different and later fauna, it appears best, until the three are found associated, to consider them as distinct. As the specific name was preoccupied by Salter's R. ohtusa, I propose R. Billingsi, in honor of the original discoverer of the species. Formation and localities. — Middle Cambrian. L'Anse au Loup, Lab- rador, on the north side of the Straits of Belle Isle, in a hard reddisli limestone; at Pioche, Nevada, it is associated with Olenellus Gilhert!, &c., in a gray granular limestone. In the llighhuid Ifa'ige it occurs in the shales above the Olenellus shale ; and one mile below Argenta, Big Cottonwood Cafion, Utah, it is abundant in a silicoargillaceous shale. The specimens in the shale are compressed, but they appear to be idcu, tical with those from Pioche, Nevat'a. ^860; f Fv WAUXOT.] MIDDLE CAMBRIAN FAUNA. 135 Hyolithes princeps Billings. < Plate xiii, figs. 5, Twi, ft. ffyolithea princeps Billings, 1872. Can. Nat , new ser., vol. vi, p. 216, figs. 4a, b, of p. 2i:i. Original (lexcription. — "Shell large, sometimes attainiug a length of three or four inches, tapering at the rate of about three lines to the inch. In perfectly symmetrical specimens, the transverse section is nearly a semicircle, the ventral [clorsalj side being almost flat, usually witli a slight convexity, and the sides and the dorsum [ventrura] uniformly rounded. In, many of the individuals, however, one side is more ab- ruptly rounded than the other, in consequence of which the median line of the dorsum [ventrum] is not directly over that of the ventral [dorsal] side, and the specimen seems distorted. This is not the result of pressure, but is the original form of the shell. Sometimes, also, there is a rounded groove ahmg the u)edian line of the dorsum fven- ifumj. The latter is somewhat more narrowly roun < !o:j.' ' related species; the differences are in the greater apical; «; fl' ." /'. excellens, 22°, and the rounded lateral angles, those of ff. pn.tc(\ • 'iin^ quite sharp and the apical angle 15°. The SI. 11 •• sjjells o{ JI. princepfi are much like those ofiT. Americanus, the i)riii(jipal difference being in the sharper ventral angle of H. Ameri- This is the largest species of Hyolithes known, H. elegans Barrande (Syst. Sil. Boheme, vol. iii, pis. xi and xv) and a few other species alomi equaling it in size. Till; spenglh. The ventral [dor.siiij .side is flat (or only slightly con vex) for about twothinis the \vi. lOL', 188.5; In the American Journal of Science, vol. xxx, [). 29'i, 1885, Mr. Matthew describes the genus Diplotheca. Mr. Matthew quotes, in the former paper, from a letter written by IMr. Alpheus Hyatt, where the latter says: " These fossils, with their dis tinct septa, are startlingly similar to certain forms of Nautiloidea, but there is no siphon. They, however, confirm Von Jhernig's and my opinion that the Orthoceratites and Pteropods have had a common, but as yet undiscovered, ancestor in ancient times." Mr. Ford speaks of the thick shell, and that it is apparently made up of successive layers of laminai. Several specimens in the Survey coUec tions show this feature. The shell is formed of three or more layers: first, a thin outer layer, with rather strong even striae that cross the flattened ventral face nearly direct and arch forward on the dorsal face, the flattened side in this species being the ventral face and not the dorsal, as in most species; the second layer appears to be of a smooth, even character, much like a filling between the outer and inner shell; the inner shell is thin and concentrically striated in a slightly ditt'ereut (864) WAI mi am slK slij B. spt bei 1 as WAICOTT.] MIDDLE CAMBRIAN FAUNA. 139 manner from the outer shell; a fourth layer appears to exist in one ex- ample, but it is too obscure for study. 1 find associated with the typical forms of Mr. Ford's H. Emmomi shells that form a gradation between them and H. communis. The slightly convex dorsal side becomes flat and then slightly raised, as in H. communift. With a series of specimens, it is difficult to determine spec'llic diflorciices between them. Following the series towards the more rounded forms, we find that H. im])ar is readily reached. H. com- viuniH appears to be the central portion of a series uniting H. impar and H. Emmonai. The most decided point of difference between H. communis and H. Emmonsi is the apical angle, that of H. communis being about 13° and that of H. Emmonsi about 8°. The two specimens 1 ave before me of H, communis from Bic show only coh centric stiise, as in M. Emmonsi. H. communis var. Emmonsi is associated with E. Americanus, H. com- munia, H. impar, Hyolithellus micans, Stenotheca rugoaa, &c. The cross section of the tube is much like that of H. teres Barrande (Syst.* Sil. Boheme, vol. iii, pi. x, fig. 4), except in the slightly convex ventral face. Formation and locality. — Middle Cambrian. Even-bedded and con- glomerate limestone on the ridge east of the city of Troy, New York. Hyolithes impae Ford. If I Plate xiv, figs. 1, la^e. Hyolithes impar Ford, 1872. Amer. Jour. Sci. , 3d ser., vol. iii, p. 419, figs, la, h, 2a, 6. Original description. — " The shells of this species are plump, elongate bodies, tapering to an acute point. The largest specimen obtained would, if perfect, be 1^ inches in length. The usual length, however, is about 1^ inches. The section is generally broadly and regularly oval, but in some specimens is rather more flattened on the ventral [dorsal] side than in the diagram of the one below given. Some specimens show a tendency to become keeled along the dorsum [centrum], but this feat- ure is rare and not well defined in any case. In an imperfect specimen 1.14 inches in length the rate of tapering on the ventral [dorsalj side is .10 of an inch m a distance of .60 of an inch. The width of the tube at the aperture is .32 and the depth .20 of an inch. In this specimen the lower [upper] lip projects beyond the limit of the dorsum [ventrum] .14 of an inch. The surface is ornamented with fine engirdling lines, which upon the ventral [dorsalj side curve gently forward, thence more sharply back- ward upon the sides until they reach a point at about the middle of the erculum are thiu and of a Anely lamellar structure, smooth and shining. "Occurs at Bic and St. Simon ; also, at Troy, New York. " Collectors, T. C. Weston and S. W. Ford. "Sometimes numerous small specimens from ^ a line to 3 lines iu length are found with the operculum on the same slab. "This shell appeal's tomeat])resent to constitute a new genus, differ- ing from the majority of the sijecies of HyoIitheH in its circular section, the operculum not divided into dorsal and ventral lines, and in the remarkable system of muscidar impressions on the interior. Barrande has tigured an operculum of the same type, differing from this in having only three instead of five pairs of impressions. They are, however, arranged on the same plan in both the Canadian and Bohemian species. It is possible that our species may be a Salterella." From material in the collections of the United States Geological Sur- vey, I find that the outer surface of the shell, although apparently smooth in many specimens, is also marked by concentric strife of growth that in some examples are quite strong and regular in arrangement. The scars on the operculum also show lines of growth. The shell, for tiie first 10""" or 15""", is often curved and almost twisted in some examples. All the larger portions seen are straight. Tiie cross section is circular or broad-ovate, as is seen by comparing the outline of different examples of the opercula. Why Mr. Billings suggested the possibility that this species might be a Salterella I cannot tell, as it appears to have nothing iu common with it except a circular or ovate cross section. Formation and localitien. — Middle Cambrian, GeorgiaFormatiou. Con- glomerate limestone at Bic and St. Simon, Canada, and Troy, New York. A species of Hyolithellus, apparently a large H. micans, occurs with the Middle Cambrian fauna, in the silico-argillaceous shales, one mile billow Argentii, Big Cottonwood Canon, Utah. Genus SALTERELLA Billings. SaUv.rella Billiiigs, 18fil. Geology of Vermout, vol. ii, y. 1)54. Jdim, 18(50, Pal. Foss., vol. i, p. 17. ■ Onginal descnption. — " Small, slender, elongate, conical tubes, consist- ing of si^veral hollow cones placed one within another, the last one form- ing the chamber of habitation of the animal. The cross section of these tubes is cir(!ular or subtriangular, and they are either straight or gently curved ; the surface is concentrically or longitudinally striated. " I think these fo.ssils, although no doubt allied to Serpulites, suffi- ciently different therefrom to constitute a distinct genus. Their struct- (869) ■7 .'ilvv's'.'nji -'fl ■■■■■'■■ '^^1 ■ '-'PI .', IS] -:■ . h •5 ::iPi 144 CAMBRIAN FATTKAS 07 NORTH AMERICA. titnix.M. ur« \H MO compnct timt tli«\v am Heldoin foniif). Idem, iti'' Pal. Fobs., v"l. i, p. 18. Original description. — " Elongate, conical, gently curved, from six to eight lines in length and from one line to one and a half in wi 1th at the aperture. Surface ornamented with small encircling stria) just visibh- to the naked eye. "This species is larger thaa 8. rugona, always a little curved, not so abundant, and when weathered does not present the sharp imbricatinji annui'ations of that species." The species in the Winooski marble is observed only on the polished sections, and it is very difficult to determine its specific characters. It appears to have a smooth outer surface, as no annulations arc shown in the longitudinal sections. In form it varies from the tlo8(!ri])tion of /S. pulchella, in being shorter and larger at the aperture; but, as we find numerous examples of a form that corresponds to 8. pulchella 300 feet higher in the section, associated with the casts of shorter, stouter shells, and also forms that appear intermediate between the slender and stouter examples, it is probable that all belong to one species. In all the specimens yet obtained but a single shell or sheath is shown. This may be owing to the fact that in those from the "Winooski marble the sep arate shells may have disappeared in the semi-crystallization to which the calcite replacing them has been subjected, and all the specimens from the gray and reddish magnesian limestones are in the form of casts of the interior and exterior surface or else showing only the outer sur- face. ' ' . (870) . WkUXTt.] MIDDLE CAMBRIAN FAUNA. 145 SaUcreUa pulchella was first annouuced as occurring in the Georgia Group of Vermout by Mr. BillingM (Can. Nat., 2(1 ser., vol. vi, p. 351, 1871), who identified it in frajrnients of the Winooski niurbh' from Swunton, Vermout, sent to him by Mr. Solon M. Allis, of Burlington, Vermont. Dr. A. R. C. Selwyn, Director of the Geological Survey of Citnada, found a weathered specimen in the conglomerate limestone of Point Levis that shows a cluster of the tubes of this si)ecies in a beautiful Htate of preservation. Dr. Selwyn kindly gave me permission to use the specimen for study and illustration. Several of the shells show, in cross sectiousj three tubes or coues, one within the other, the walls of the inner cones blending at the larger end with the general wall of the shell.. The occurrence of this species at Point Levis does not indicate that it belongs to the Upper Cambrian (Potsdam) fauna or to the Cal- ciferous fauna of the shales in which the pebbles holding it are imbedded, as the pebbles are rolled and worn and are a jiart of the detrital inatter making up the Point Levis strata and were derived from pre-existing rocks, as are also the pebbles and bowlders carrying the Potsdam and Calciferous faunas. Formation and localities. — Middle Cambrian, Georgia Formation. L'Anse au Loup, Labrador, on the north sif ^i V 146 CAMBRIAN FAUNAS OF NORTH AMERICA. [BULL. 30. •^ it' i i'^i't. * i- ^ m m sir This is the most marked species of the genus yet desc :ibt^cl. As far as known to me it has not been discovered except at the typical locality. Formation and locality. — Middle Cambrian, Georgia Formation. L'Anse au Loup, Labrador, on the north side of the Straits of Belle Isle. ^ CRUSTACEA. Genus LEPEEDITIA Eoualt. Leperditia Roualt, ia")l. Bull. Sue. Gutened between the laminiB of the shale, and only a slight rim arouDu the ventral, an- terior, and posterior margins indicates any original irregularities of the surface. The unusual feature is the presence of the spinous dorsal angles. A tendency to an almost spinous angle is seen in some of the Silurian species of Leperditia. This is the largest species now known to me from the Cambrian System. Several species occur at the Pots- dam or Upper Cambrian horizon tiiat will be described with that fauna. It may be that the reference to Leperditia is incorrect, but, with the evidence at hand, it appears to be re«iuired. The form suggests at first a reference to the carapace of a phyllopod crustacep allied to Hymeno- caris or Prctocaris, but the straight dorsal margin and acute dorso- lateral ausrles are very much against this view. Formation and locality. — Middle Cambrian. One mile below Argenta, in Big Cottonwood Canon, Wasatch Mountains, Utah. Genus PROTOOARIS Walcott. Protocaria Walcott, 1884. Bull. U. S. Geol. Survey, No. 10, p. :,0. (Dated 1884, but not generally dlHtributed until 18H.").) Carapace without evidence of a dorsal suture, rounded on the dorsal line, aud bent downward on the sides ; without any rostrum. Body many-;iointed, 31 segments extending out from beneath the carapace, the last segment broader than the preceding and terminating iii two spines. Type, Protocaris MarHhi. In comparing Protocaris (P. Marshi) with Ilymenocaris [H. vermi- Cauda Salter, 1852, Brit. Assoc, liep., i)t. 2, Xotice.^ . d Abstracts, p. 58; Mem. Geol. Surv. Great Brit., vol. iii, p. 293. »!ate ii, figs. 1-4; plate V, lig. 25, 18GG), we find that in the simple b* il or folded eyeless shield or carapace tuey are closely related, but in the structure of the body tliey differ uiaterially. Ilymenocaris has, in O'le instance, 9 strong segments shown in its more elongate body, the terminal one ending in threa pairs of spines; usually 6 or 7 segments are seen; 8 or 9 are less frequent (Brit. Assoc. Rep. 1883, p. 219). Protociiris has 30 narrow seg- mtTits, a huge terminal segment or telson, with two rather strong caudal or terminal spines. (873) m K'H. ',( ''':■ I' h 'I'^i 148 CAMBRIAN FAUNAS OF NOETH AMERICA. iBnix-W. Peotocabis Makshi Walcott. Plate XV, fig. 1. Frotoearia MaraM Walcott, 1884. Bull. U. S, Geol. Survey, No 10, p. 50. (Dated 1884, but not generally distribnted until 1885.) The specimen on which the genus and species are founded is com- pressed between the laminee of the slate so that the entire outline of the carapace is shown and the body is widened out. As flattened the carapace is rounded quadrangular in outline, with a more or less dis tinctly defined marginal rim all around. The general surface appears io have been smooth. No evidence of eyes. The body projecting beyond the carapace is about two thirds as long as the carapace, narrowed posteriorly and made up of numerous nar- row segments, each about one-third of a millimeter in breadth ; the last segment or telson, which is 2.5°"" long, supports two caudal spines 7 or 8°"" in length ; 30 segments appear between the posterior edge of the carapace and the telson ; the segments appear to have been smooth and without a spinose or crenulated posterior margin ; the telson and cau- dal spines also appear to have been smooth and without ornamentation. Dimensions. — Total length, 42°"" ; lengih of carapace, 21""°; width, 26™°' ; length of body, IS™"*, exclusive of caudal spines ; width of body where it passes beneath the carapace, 10™"* ; at telson, 4"™. The specific name xs given in lionor of Prof. O. C. Marsh. Formation and locality. — Middle Cambrian, Georgia Formation. Par- ker's farm, town of Georgia, "Vermont. This is probably the oldest Phyllopod crustacean known at the present time. We know nothing of the animal that inhabited the shell (the shell itself is flattened by compression), but by flattening out the cara- pace and segmented body of Apus glacialis, or any allied form, we see at once the striking resemblance between the recent Apus and ancient Protocaris, the most marked difierence being the absence of eyes in the Cambrian Protocaris. Mr. J. L. Kiugsley requested me to study Protocaris with a view of ascertaining its relations to Apus, but the material is too imperfect to arrive at a satisfactory conclusion. The animal is Apus-like, and it also appears to be connected with the ISTebalidse through Bymenocaris, Pel- tocaris, Ceratiocaris, »&('. Ip this connection T wish to quote an observa- tion by Prof. E. Ray Ldpoaster. He says : " Apus cancriformis is, iu many respects, one of the mo.st important of the Crustacea. * * * It possesses peculiarities of organization which mark it out (together with its immediate congeners, the Phyllopoda) as an Archaic foru), probably standing nearer to the extinct ancestors of the Crustacea than any other living members c^ the group." ("Observations and reflec- tions on Appendages and on the Nervous System of Apus cancriformis," Quart. Jour. Micro. Sci., vol. xxi, n. ser., p. 343, 1881.) (874) WALCOTT.] MIDDLE CAMBRIAN FAUWA. 149 PCECILOPODA. Genus AGNOSTUS Brongniart. Agnottita Brongniart, 1822. Crust. Foss., p. 38, pi. iv, figs. 4a, h, AGNOSTUS INTERSTRICTUS White. Plate xvi, figs. 6, 6a. Agnoatus interatrictua White, 1874. Geog. and Geol. Expl. and Surv. West 100th Merid., Prelim. Rep. Invert. Foss., p. 8. Idem, 1875. Vol. iv, pt. 1, p. 38, pi. ii, figs. 5o, b. Original description. — "Head and pygidium of almost exactly equal size and general shape and otherwise closely resembling each other. " Head a trifle broader than long, regularly rounded in front ; sides at the posterolateral regions subparallel ; postero-lateral angles trun- cated ; the whole exterior margin, including the truncated portions just named, provided with a narrow, raised rim, the elevation of which forms a linear depression, or groove, between it and those portions of the bead which it incloses ; space between this marginal depression aiiv^ the glabella a little wider posteriorly than it is in front, convex throughout, and its surface apparently smooth. Glabella conical, widesi posteriorly, moderately convex, sides nearly straight, well de- fined by the dorsal furrows, abruptly rounded in front ; a minute tuber- cle situated on the median line near the posterior end, and a shallow groove or furrow extending across near the front end, defining a frontal lobe of moderate size. " Thorax narrower than the head and pyf;idinm, giving the body the appearance of being constricted at the middh >xial lobe broad, con- sisting of two segments, both of which are tuning at the ciuIn adjoining the dorsal furrows; lateral lobes very narrow; 'jjleurje almost as wide as long; each pleura tumid and rounded at its exterior end. " Pygidium having an outline like that of the head, and is also pro- vided with a similar elevated marginal rim and linear depression within It ; axial lobe a little longer than the glabella, and consequently that lobe reaches a little nearer the posterior margin of the pygidium than the glabella does to the anterior margr.i of the head, moderately convex in elevation and also in each lateral outline ; a minute tubercle is situ- ated on the median line near the anterior end, corresponding in size and relative position with the one on the glabella before mentioned ; space between the dorsal furrows and the margin convex, its surface ai)parently smooth ; upon the outer edge of the border of the pygidium, at each side and a little nearer to the axial extremity than to the antero- lateral angles, there is a minute protuberance, suggestive of an incipient spine. Besides the slight differences between the head and pygidium, already referred to, the pygidium differs also in having a faint appear- ance of segmentation of its :< xis and in a slight folding backward of the marginal rim at the antero-laieral angles. (875) ■iV4ii' 150 C AMEBIAN FAUNAS OF NORTH AMERICA. [BULL. 30. 1 _ 1 " Length of body, 8™" ; width of head and also of the pygidium, 5mm . width of thorax, i"'™. "This beautiful Agnostus is quite unlike any described American species, and is more nearly related to A. integer Beyrich, from the Primordial strata of Europe, than any other known to me. Compared with that species, it is found to reach a larger size; its glabella is nar rowed in front instead of having its sides near ;? parallel ; the axial lobe of the pygidium is narrower behind than jn front, instead of being of nearly the same width at each end, and has tlie sides of that lobe con- vex instead of nearly straight, as they are in A. integer.'''' Direct comparison with specimens of Agnostus pisiformis shows a striking similarity between it and A. interstrictus ; the diilerences con- sist in the form, and this is owing largely to the compression to wiich A. interstrictus has been subjected. Agnostus bidens Meek (see Mono- graphs U. S. Geol. Survey, vol. viii, p. 26) and Agnostus tumidosus H. & W. (Geol. Expl. Fortieth Par., vol. iv, p. 231), of the Upper Cambrian, are also closely connected with varieties of A. pisiformis. Our knowledge of the American species of the genus Agnostus is now very imperfect, and much work is needed to obtain a thorough understanding of them. A species of Agnostus occurs in the Prospect Mountain Cambrian • limestone of the Eureka District, Nevada, that appears to be, in the head shields, identical with A. interstrictus. It also may be identilied with A. communis H. & W. (Geol. Expl. Fortieth Par., vol. ir, p. 228, pi. 1, figs. 28, 29). Not \vishing to' introduce a doubtful occurrence of another species into the fauna, I identify the head shield with A. inter- strictus, which we know to occur at about this horizo) at another locality. Formation and localities. — Middle Cambrian. Bluish-gray calcareous shale, Hou.se Range, Antelope Spring, Western Utah; Shaly limestone, 600 feet above quartzite, eaat slope Prospect Mountain, Eureka Dis- trict. Nevada. , AGNOf^.TUS NOBiLis Ford. Plate xvi, fig. 7. . . Agnoxlua nohilia Ford, 1872. Amor. Joiir. Sci., 3d ser., vol. iii, p. 421, figs. 1, 2. Original description. — "Head and pygidium of nearly the same size and form, both exceedingly convex. The head is broadly .semi-elliptical, wider than long, the length to the breadth about a.s 5 to G. Convexity greatest along the median line, reaching its maximum on a straight hue joining the posterior angles. From thence the sloi)e is nearly equal to the front and sides. The sides, anterior margin, and part of the jxks- terior margin, abrujjtly concave, rounded, and slightly incurved. Po.s- terior angles rounded. The posterior outline is slightly concave lor a short distance on either side of the middle, leaving a .strong, tapering, median i)rqiection. The extremity of this jnojection is truncate and appears to form a nearly flat articulating face. The head is surrounded (876) ' / WALCOTT.I MIDDLE CAMBRIAN FAUNA. 161 by a narrow convex border directed a little downward, of uniform width, or but slightly attenuated on the posterior outline. On either side of the head this border is set o(f with a row of prominent tubercles, from seven to eight in each row. No tubercles have been observed on the extreme front and posforior portions of the border. The surface of the head, including Ihc border, is transversely crossed by numerous faintly impressed lines, curving backward, for the most part invisible to the naked eye. ''The pygidium is of equal length and width with the head. The con- vexity, however, is a trifle greater along the middle, and the anterior angles rather less rounded than the corresponding angles of the head. The greaiCoL convexity occurs at the anterior thiid of the pygidium. The anterior outline is slightly concave at the middle and is then feebly rounded in passing outward and backward to the angles. The contour of the sides and posterior margin the same as that of the sides and an- terior margin of the head. A narrow margiual border similar to that of the head, though not tuberculated, surrounds the pygidium, termi- nating on either side of the concave portion of the anterior outline. The surface is covered with delicate lines similar in character and direction to those of the head. " The two extremities are connected by a single thick thoracic ring. This ring is partly shown in the figure. From the appearance of the figure, however, there would seem to be room for a second ring, but this appearance is due to the damaged condition of the head. "Two specimens only of this species have been obtained, one a head with a small portion of the pygidium; the other a nearly perfect indi- vidual. The dimensions of the latter are as follows : Length of entire animal, .64 of an inch; length of head along the median line .30, width at posterior angles .30 of an inch; median length of pygidium .30, width at anterior angles .36 of an inch ; width of head aiul pygidium at one-third the length of each from their smaller extremities, each .28 of an inch; width of thoracic ring, .10 of an inch. This is likewise the width of the ci-cave portion of the pygidium with which it lies in con- tact. Greatest depth of pj'gidium .14 of an inch ; greatest depth of head .12 of an inch. "The proportions of tlie other '-.ead slightly difterciit, the length being .34, the width .39, and the greatest depth .14 r,t" an inch. The specimens were found lying close to each other in the same hand frag- ment of limestone. Occurs in even-bedded limestone east of Troy, New York, in the same layer with Olenelhis asaphoUJes, Agnostiis lobatus, Oho- lella cwlafa, and O. desqimmata.^^ Mr. Ford states that he is not sure which is the cephalic shield; also, that the species is of the same type as A. parilis Hall, of the Potsdam saiulstone of Wisconsin, but it differs in size characters too much to be specifically related. Mr. Ford informs me that the type 8i)ecimen is (877 M My m th r* ' K 152 CAMBRIAN FAUNAS OF NORTH AMERICA. [BULL. 80. t lost, so we can only reproduce the rough wood cut given with the orig- inal description. Formation and locality. — Middle Cambrian. Even-bedded limestone on the ridge east of the city of Troy, New York. Genus MIORODISOUS Emmons. Miorodiaous Emmons, 18.55. Amer. Geol,, vol. i, pt. 2, p. 116. ' Type, M. quadricostatus. Original description.-^^* M'mnt^, oval, middle lobe of the cephalic shield strongly developed; ribs of the body or abdomeu, four; of the tail, four or five. The form of the cephalic shield is only obscurely in- dicated ; the size of this trilobite is shown in the small figure. It is found in the white fragile shales of Augusta County, Virginia, associ- ated with minute molluscas and graptolites." 1 have long had a suspicion that the original specimen on which the species M. quadricoatatus was founded was a youug specimen of Trinu- cleus concentricu8, or a species of that genus, although It might be the young of some species of the genus Ampyx; the former is more proba- ble, as specimens of the latter genus are of rare occurrence in American strata and Trinucleus concentricus is quite abundant at the same hori- zon in which Dr. Emmons found the specimen described by him. It is the type of the young Trinucleus, as may be seen by comparing it with Barrande's figure of T. ornavm, showing four segments in the thorax. The glabella is clavate and of the type of that of Trinucleus; the pygidium is essentially that of Trinucleus, as are also the thoracic seg- ments. When collecting from the Hudson River shales, in Central New York, I found the heads of T. concentricus distorted and with the punc- tate margin and genal spines so broken away that they appeared similar to the head of M. quadricostatus. We now know that the light-colored, fragile shales of Augusta County, Virginia, belong to the Hudson River group, and that they carry graptolites and minute shells such as Dr. Emmons mentions. In view of these facts and since all the species subsequently referred to the genus Microdiscus have the head and pygidium subequal in size and form and a cylindro-couical glabella, I am inclined to consider Emmons's type as belonging to the genus Tri- nucleus and take as the type of Microdiscus the next species referred to it, M. punctatus. The above was written before I had read M. Barrande's observations on the same trilobite. He was of the opinion that Dr. Emraons was probably in error in referring the species to the lowest geologic hori- zon of his Taconic system and that M. quadricostatus recalled the young of Trinucleus : " D'apr^s cette circonstance, que la forme de la t6te est obscur^ment indiqu6e, il est impossible de juger avec 86curit6 1 nature de ce Trilobite. Sa taille et ses appareuces nous porteraient k croire que le specimen flgnr6 repr6sente le jeune Age de quelque esp^ce dont (878) WAI be con- (879) I' w\ V m >rA If- " 164 CAMBRIAN FAUNAS OF NORTH AMERICA. I BULL. 30. fined to the Cambrian system ; M. punctatus, M. sculptus, and M. pulchel lu8 appearing in the Lower Cambrian ; M. speciosus, M. Meekly M. Parleri, and M. lobatus, in the Middle Cambrian; iind, if Pemphigaapis buJJata proves to belong to the same group, we have one species from the Upper Cambrian, and all the species now referred to Microdiscus would then be referred to Peniphigaspis, as Emmons's original name of MicroflLscus could not be retained, as it appears to have been founded on a specimen of the genus Trinucleus. In my review of the fauna of the St. John group of the Hartt collec- tion I referred the St. John species to M. Dawsoni and M. punctatus. A reconsideration of the last species causes me to refer it to the species pulchellus, a name proposed by Mr. Hartt in cataloguing the species of the St. John Formation (Bull. U. S. Geol. Survey, No. 10, p. 24). Microdiscus speciosus Ford. ,, Plate xvi, figs. 3, 3a-c. MicrodUcuB apecioaus Ford, 1873. Amt>r. Jour. Sci., 3d Ber.,vol. vi, p. 137, figs. Va, 6. Idem, 1877. Same journal, vol. xui, p. 141. Original description. — "Head destitute of eyes and sutures, semi-ellip- tical, with a conspicuous border all around, thickened at the edge, which in the majority of cases carries from Ave to six minute tubercles on each side; border expanded in front. Glabella long, conical, prominent, smooth, without neck furrow, extending in an obscurely triangular ])ro- jection slightly beyond the po.steriort)utline, separated from the cheeks by rather wide and deep dorsal furrows, sometimes, though only in very rare instances, obscurely loi 1 by from three to four faint furrows on each side. Cheeks convex, prominent, well defined by the dorsal and marginal furrows. Posterior angles narrowly rounded. "Thorax with four equal segments. Pleurfe pointed, straight except at their extremities, which are bent down and slightly recurved, deeply grooved for nearly their whole length. The rings of the axis have a slight groove across them in the posterior half of each. The fourth or hindmost ring appears to be anchylosed to the pygidium; at least, it invariably accompanies it when the latter is found isolated. " Pygidium as long as the head and of nearly the same shape, but slightly narrower, taking the extreme measurements and more rapidly tapering, gracefully curved in outline. Marginal rim distinct all around, widest anteriorly, distinctly raised or thickened at the edge. Axis •conical, sometimes acutely so, long and slender, extending very nearly to the margin, divided by faint cross furrows, directed slightly back- ward into eleven rings or segments. Side-lobes highly convex and with- out furrows. The axis and side lobes appear to overhang the marginal rim at the posterior extremity, giving the border the appearance of being only about half as wide behind as it is in front. " The entire surface is finely punctate. In one specimen of the pygid- (880) WALCOTT.] MIDDLE CAMBRIAN FAUNA. 156 iuin, out of a large number of perfect specimens examined, there ap- ])ear8 to be a twelfth ring in the axis. " Length of a specimen of the usual size with all the parts in place, but too imperfectly preserved to bo fipurod, half an inch. Length of thorax, 0.13 of an inch. 1 have seen but a single specimen showing con- cUisively the true number of thoracic .segments. Tliis si)ecies had the habit of rolling itself up into a ball, and is quite often found in this state. In the specimen just noticed, the pygidiuin is bent slightly under the body. Nearly all of the specimeas that I have seen that were in a perfect condition before extraction, exhibit this tendency to coil themselves up, which appears to account for the thorax breaking away in most cases. " This pretty little trilobite occurs in both even-bedded and conglom- erate limestones of the Lower Potsdam at Troy; also, at Bic Harbor, Canada, where it has been collected by Mr. T. C. Weston, of the Geo- logical Survey of Canada. The Troy specimens were collected by the writer. It is a rather common fossil at Troy, the head and pygidium usually occurring detached from the thorax. The head sometimes attains a length of 0.38 of an inch, but this is quite unusual. "This species closely resembles Microdisciis pttnctattis (Salter), from the Menevian group of Wales (Quart. Jour. Geol. Soc, Aug., 1804, p. 237) ; but it difters from that species in not possessing a neck spine, in the greater number of its caudal rings, and in having the marginal rim of the head tuberculated. The head, compared with that of Micro- discus JDmvsoni, from the St. John group of New Brunswick (Acadian Geology, Dawson, 1808, p. 054), is proportionally longer, and is want- ing in the grooves of the border of that species." Mr. Ford subsequently discovered more perfect speciUifjns than those from which the above description was drawn, that pr )ved that the thorax was comijosed of three segments, also that the postenor segment was not anchylosed to the pygidium. The pygidium of Microdisvus imlchellus Hartt is of the same type as +liat of M. speciosus, and it has eleven rings on the axial lobe. The head, however, varies materially in the possession of a strong nuchal spine, crenulated border, and in the proportions of the glabella and cheeks. M. speciosus is not a rare form at Troy, although not occurring in as great abundance as M. lobattis. Formation and localities. — Middle Cambrian. Conglomerate aiid even- bedded limestones, on the ridge east of Troy, New York; also, at Bic Harbor, Canada. IIiCKODiscus Meeki Ford. Plato xvi, fig. 4. Microdiscua Meeki Ford, 1876. Amer. Jour. Sci., Sd ser., vol. xi, p. 371. Original description. — *' Head broadly rounded in front, nearly semi- oval in outline, greatest width at about the mid-length, slightly narrowed (881) 156 CAMBRIAN FAUNAS OF NOBTH AMERICA. (BULU30. in passing backward from tbis point to the angles. Glabella conical, about two-thirds the length of the bend, with two straight, moderately deep furrows extending all across, dividing the glabella in advance of the neck furrow into three parts of nearly equal length. Neck furrow extending all across and deeper than the other glabellar furrows. The form of the neck segment cannot be clearly made out, owing to the damaged condition of the specimen at this point. Dorsal furrowH narrow, not deep, dying out toward the front of the glabella. Cheeks prominent, much swollen in the posterior third, without eyes or sutures. Marginal rim well defined all around, widest in front, with a conspicu- onsly raised edge, inside of which there is a nearly flat or feebly con- cave space, and so bent upward in front as to give to the head, on a side view, a kind of slipper-like appearance. On either side of the head, just inside of the raised marginal edge, there are three small tubercles situated within the limits formed by a line drawn across the head through the middle of the cheeks and another drawn parallel with it just in advance of the front of the glabella. "Greatest width of the head, one and one-half lines; length along the median line, including the neck segment, the same. Differs from Microdiacus {Agnostus) lobatns Hall (Pal. N. "X., vol. i, p. 258, pi. Ixvii, figs. 5a-f), fron) the same locality, in its shorter and transversely fur- rowed glabella, its tuberculated margin, and in its general proportions." The figure illustrating this species was drawn by Mr. Ford from the type specimen, which is the only one yet known of the species. Formation and locality. — Middle Cambrian. Conglomerate limestone, on the ridge east of Troy, New York. MiCRODISCUS LOBATUS Hall (sp.). I Plate xvi, figs. 1, la, I. Agnostus lobatua Hall, 1847. Pal. N. Y., vol. i, p. 258, pi. Ixvii, figs. 5a,/. Microdiacus lobatua Ford, 1873. Amer. Jour. Sci., 3cl ser., vol. vi, p. 135, foot-note. Original description. — " Minute, trilobate, with a narrow border around the base and sides; middle lobe often with a small tubercle near its larger extremity. "This species bears considerable analogy to the Swedish specimens from a similar geological position, but they are not identical. Our spe- cies is always smaller, and I have never seen the small node or tubercle at the base of the central lobe ; but it presents a similar character on the other extremity. All our specimens have the appearance of the caudal shield of a small trilobite, and two or three iuear to have been of a more delicate texture than the anterior 15 segments. The pleural groove of the lateral lobes is broad, flat, and continued outward beyond the genal ungles to the union of tli.> two niargins of the segment to form the terminal spine or point. Pygidium small, ovate, terminating in three points posteriorly ; the axial lobe occupies all the central portion, leaving a narrow pleural lobe on each side; posterior margin concave between the outer terminal points, and with a slight point at the center. Surface of the entire body, except the free cheeks, very finely gran- ulose under a strong magnifier ; from the base of the eyes, irregular, venulose lines radiate towards the outer margin. Observations. — Tlie genus appears to be one intermediate between the genera Paradoxides and Olenellus, or a form in which the character- 'The plouial auglo is tbo auglo o tlio posterior margin of the head, opposite the geuiculatiou of the pleural lobo of the thorax. 1VAI.C0TT.1 MIDDLE CAMBRIAN FAUNA. 161 istios of Paradoxides aro changing into those of Ok^nellns, the hea;l and the tirst 14 sej^uients u-inj; in all ]Kirti(!nlars the type of Oleiiellus, and the pygidiura and 10 posterior segments more the type of Para- doxides ; the fifteenth segment represents the telson'of Olenellus Tliomp- soni. Under remarks ou the genus Olenellus, the relarioiiships to that ge- nus are mentioned, and we will next consider the body of Mesonacis hack of the fourteenth segment. The fifceenth segment fits snugly up against the fourteenth ; the axial lobe is strong and su])ports the base of a long, slender spine that^, as now preserved, extends back to the i)yj.vidium j the base of the spine originates on the dorsal surface of the segment and also extends back so as to include the posterior margin, and causes the latter to curve back towards the center; the lateral i)lourfB of the segnK-nt are short, and in their structure are diminntive representatives of the large pleurae of the . egments anterior to tha tifteenth. The succeeding eleven posterior segments apjjear as though formed of a more deli<;ate test than the anterior portions of the body, as they are much more tlattened and compressed than the latter and the pleu- ral grooves are almost obsolete. The pygidium is also small and deli- cate. The body back of the spine-bearing segment appeal's as though be- longing to a different animal, and looks more like that of a Kemopleu- rides than either Olenellus or Paradoxides, but, on a close examination, the pygidium is found to be much like that of 7'«rroacli very closely U» that of Mesonacis Vcnnontana, and I was surprised when i i'ound that the f(»rmer Syst. ISil. H(]li('iu<', vol. i, Irro'i. Bull. ;30- -11 (887) 162 CAMI5RIAN FAUNAS OF NORTH AMERICA. [BULL. 30. II li &c., may be (joiuparcd with the species under consideratiou. The gla. belhi and the eye lobes \'ary from all excei»t P. Kjerulfi. The thorax has already been spoken of in the remarks following the description. The denticulated form of pygidium in the genus Paradoxides with two terminal i)oints is shown in the pygidia figured by Mr. Matthew' from the St. John group; and on the pygidia of P. rugidosus Corda, P. Ly- elli Barrande, P. expectans Barraude, and P. Oelandiem Linnarson, four terminal i»oints occur, as far as can be determined. The one specimen showing the i^ygidium of M. Yermontana has three terminal points, cue central and one on each side. Under the general remarks on the genera Ulenellus, Mesonacis, and Paradoxides, the generic relations of Mesonacis Vcrmontana are still further discussed. Formation and /ocwV^Vt/.— Middle Cambrian, Georgia Formation. Park- er's quarry, township of Georgia, Franklin County, Vermont. Speci- mens corresponding to the head of this si)ecie8 occur Jit Bonne Bay, Newfoundland, and L'Anse an Loup, on the north side of the straits of Belle Isle. Genus OLENELLUS Hall. Elliptocephala Einiiioiis, IS IG. Af;riciiltiii(.' of Ni'w York, pt. 5, p. 65, figs. 1-3. ElUptocepJialus Eirimoiis, IB.'jo. Aiuer. Geo!., \)t. ii, p, 114. EUiptocephaliis ^lUirctm, I860. I'loc. BoHton Soe. Nat. Hi.st.,p. 371. Oleniis Hail, 18.")!). Twcimi Aim. R.'p. N. Y. State C.ib. Nat. Hist., p. 59. Olenus Marcon, 18K). IJiill. Soc. Gt^ol. ile Fr/uice, ;{'■ n6v., t. ix, p. 25. Barrandui Hall, IriCiO. TliirteentU Ann. Kcip. N. Y. 8tate Cab. Nat. Hist., p. 115. Idem, • 1801. Gt!oloj>y of Vorniotit, vol. i,p. :i6"J. , Paradoxkles EniuionH, l8G0. Manual Geol., p. ii80. Paradcxidca IJarrandc, 1801. Bull. Soc. G(?ol. do France, 2"= sdr., t. xviii, p. 277. Paradoxides Maroon, 1805. Proc. Boston Soc. Nat. Hist., p. 245. ParatZorirfM Billings, 1801. Gfol. Vcrniont, vol, ii, p. 9.">0. Idem, ISChi. Gool. Canada, p. 953. Olenellus Hall, l.-^O's!. Fiflecnth Ann. R.^p. N. Y. State Cab, Nat. lli.st., p. 114. OleneUm Marpon, 1802. Paniplilct, p. 5. Cainbiidj;t', Mass. OleneUus Bi'.liugH, 1805. Pal. Foh.s., vol. i, pp. 11, 305. OleneUm Ford, 1877. Amor. .Jonr. So!,, vol. xiii. j). 205. OloieUns W^iitfiold, 1884. Bull. Amor. Mn.s. Nat. Hisl ., vol. i, p. 151. Olenellus Walcott, 1«84. Monogni))bs U. S. (.Jcol. Sur\ oy, vol. viii, ]). 28. Dr. Emmons originally [daced a s])ecies of this genus under the ge- neri(r name of JCllijiloceidiala (I^^'-IO), ''onsidcring it a new g(Mieri<5 iorni ; subsequently (IsrM, Amer. Geol., p. 114) he called atfisntion to tlic simihirity of the name to Ellipsoceplialus (Zenker, IS.'J.'J), but concluded "to retain it for the i)resent." ]\loie recently Die name Elli])to(;epliala has been j'ecognized {OlancUu.s {EUipiocvphalus) asaphoiiles, Vovd, Amer, Jour. Sci., 3d ser., vol. xiii, p. iHib, 1877), but 1 think without good rea- ' Trans. Roy, 8oo. Canada, vol. 1, pi. x. (888) WAI.COTT. 1 MIDDLE CAMBRIAN FAUNA. 163 son, as it diflfers only by an error of spelling from Zenker's genas EUip- s(K!(*pbalu8,tlie elliptical form of tlie head being the basis of each name. The following is the original description of the genus Barrandia Hall, af't(^rwards changed to Oleuellus Hall : "General form broadly ovate or elong.ate-ovate, distinctly trilobate. Cephalic shield broad, somewhat semicircular; the width more or less than twice the length, with the posterior angles projecting in long spini- forin points ; the posterior margin is nearly straight or slightly concave, with a slight sinuosity at the outer angle just within the cephalic limb; the anterior and lateral margins have a tliickened or elevated border, wii'...n wliich is a well marked groove or depression of the crust. The fiiabellais well pronounced, of nearly equal width throughout, or slightlj' iiiinowing and rounded in front ; marked by three paifs of furrows (per- haiKs from two to four), the posterior one of which is nearly or quite con- tinuous across from the posterior angles of the eyes. The facial suture has not been fully determined, but appears to extend in a curving line from the front margin to the anterior angle of the eye, and from the posterior angle of the eye it turns abruptly outwards towards the pos tero lateral angle of the cephalic shield. "Byes large and well developed, <.iongatesemilunate, extending from near the base of the shield more than half way to the anterior margin. Ilypostoma broadly ovate, little longer than wide. "Tiiorax composed of 13 or 14 articulations, the axis being moder- ately convex and usually much narrower than the lateral lobes (and sometimes ai)parently marked by a row of nodes or short spines along tlie summit). Lateral lobes nearly flat; the ribs, to about the eighth or ninth, extemling almost rectangularly, or slightly inclined from the axis for one-third to one-half their length, where they are bent abruptly bat;k wards. The third segment is stronger and much more prolonged than the others. The last segments of the lateral lobes are produced directly backwards, or sometimes a little convergent below. The seg- ments of the lateral lobes are marked by a broad longitudinal furrow nearly parallel to the anterior margin ; leaving an abruptly elevated rid'je oi border upon that side as far as the geniculation of the segment, where the groove runs along the center, dying out on the recurved ex treniities. "Pygidium distinct, narrow, elongated, the axis narrow and acutely pointed; without rings? Lateral Jobes narrow or obsolete, and free IroMi transverse ridges or furrows." Tlie direction of the facial suture is left in dimbt. For the type speiiies 0. Tlionipsoni, Prof. Whitfield has shown it as though passing from the posterior end of the eye oblieds of Sweden, p. 28. Bihang till k. Svensk. Vet.-Akad. llaiidl. Bd. 3, N:o 12, 1 ' .i). With the first I am ii: accord, but, on comparing with Anopolenus Salteri, as illustrated by Mr. HickR ((Juart. Jour. Geo!. Soe., vol. xxi, p. isi. ti^'. 1, ItSli.")), I fail to recognize the characters uniting the two foriiis. Tiie remarkable develo})ment of the posterior portions of Anop- olenus and the peculiar glabella and eyes serve to distinguish it as a distinct genus from Paradoxides and Olenellus; and with Paradoxides tliere are the ditl'erences given by Proi'essor Hall and the writer (ante) ; but, as stated by Mr. Ford, the adult form of O. asaphoides as known to biiii dilfers only in one feature from the structural peculiarities pouped under the genus Paradoxides, and that is the segment furrow or ])lciiial groove. To this I think we may now add "and in the elon- uato, simple lelsoii or i)ygidium." One marked peculiarity is that the extended pleura of Olenellus occurs on the tliird, while tliat of Paradoxides is on the second, segment of tlie thorax. ■ before id L'ara- U4) as c sliiehl m of lilt' tend eii- le facial iiig feat- illy. Ill anient, it UELATIONS OF J'lIE GENERA PAIIADOXIDES, MESONACIS, AND OLE- NELLUS. As inentioiM'd under the description of the genus Mesonacis, that jii'iiHs is regarded as intermediate between Paradoxides 'and Olenellus, or II ltd ill preserving t^ pical features of each genus. .\l('S()na(;is is distinguished from Paji^adoxides by the character of the pleural grooVe of tlie segment, the ])resence of a dorsal spine on a mod- ilied form of segment on the fifteentii segment of the thorax, and the (liawiiii; in <»f tlie eye, esju'cially of tlie posterior end towards the gla- bella, 'fiio points of reseniblaiKU' aie the ('ontignratiou of the head, the t,vi)e()f the segments (except in the pleural groove), and the form of tb6 li.Vii'idiniii. The features of the head and tlun-axof Mesonacis, back to the fifteenth se;;iiieiil, ar(! in all (l(>1ails essentially tlios*^ ol' Olenellus, but the py- j;i referred to, does not always exist. On one specimen the fourteenth axial rin^f looks almost as if it might have formed an anterior lobe or ring of the telson ; but iu others it is seen to be distinctly separate and articulated, as are the forward axial rings to each other. This feature of the pygidium is so distinctive among all other trilobites that it alone would serve as a generic distinction, and if the condensation of parts indicates development of organization this form would appear to be below even the Paradoxides, and should pre cede it in age." From our present knowledge of these forms we reverse the applica tion made above and regard the telson as representing the condensed parts, and the form as higher in organization an*^. succeeding Paradox- ides in time. Mr. Fonl considers the relationship between Olenellus and Paradox- ides one of genetic character (Amer. Jour. Sci., 3d ser., vol. xxii, p. 257, 1881), and that Olenellus is a later and higher form than Paradoxides. We assent to this, and add that Olenellus is the representative of tlie group of Paradoxides of the I ower Cambrian iu the Middle Cambrian, and expi'esses, in one of its species at least, the decadence of that branch of the type. The examiJe is 0. Qilberti, where, in the retention and great development of the embryonic stages of growth by adult individ- uals, we have an example of the loss of power in the larger number of the individuals of a species to develop to the adult form. In other words, it is au instance of retrogression towards the earlier forms of the family to which it belongs. (893) wALCorr] MIDDLE CAMBRIAN FAUNA. 167 Olenellus Thompsoni Hall. Plate xvii, tigs. 1, 2, 4, 9 ; pis. xxii, xxiii, tig. 1. Olenus Tltompsoni Hall, 187)0. Twelfth Ann. Ecp. N. Y. State Cab. Nat. Hist., p. 59, fig. 1 on p. tiO; Pal. N. Y., vol. iii, p. 52o. Barrandia Thompsoni Hall, 1800. Thirteenth Ann. Hop. N. Y. State Cab. Nat. Hist., p. IIG. Paradoxidea Thompsoni Emmons, i860. Manual of Geology, p. 280, note A. ^'•radoxides Thompwni Banande, 1861. Bull. Soc. Gi. Bull. Am<'r. Miis. Nat. Hist., vol. I, p. 151, pi. XV, figs. 1-4. The original description ol" the species i.s a.s follows: "General form ovate, the length and breadth being nearly as six to five. Head broad lunate, with the ijostero-lateral angles much ex- tended; the width from the center to the outer margin of the eye almost equal to the width of the (jheek. Eyes (whicli are imicli crushed in the specimen) elongate semi-oval, equal in length to the space between the anterior angles and the frontal margin ; glabella distinctly lobed, nar- rower in front. "Thorax with the lateral lobes about once and a half as wide as the luitldle lobe, consisting of fourteen articulations, the third one of which is much longer than the others, and curving downwards with an exten- sion reaching as far as the line of ;irticulation of the seventh rib. The posterior articulations are bent abruptly backwards, so that the free extremities are pai^allel with the axis. Pygidiuin small, pointed, with- out visible rings and having a narrow ridge running down the centre." Prof. Hall revised this description in jiroposing the generic name Bar- randia. (See description under OJeneJlufi, ante, ]). 101.) In 1884: Prof. Whitfield gave a description of the direction of the fecial sutures and figured examples of the species that ])roved the pygidium to be as given in Prof. Hail's second figure (Thirteenth Ann. Eep. ^. Y. State Cab. Nat. Hist., p. 110, 1800) and ahso rruich more prolonged. Prof. Whitfield's referenc to the spe(nmcn "figured in lOth Kep. State Cab." ])robably refers to the figure in the fifteenth report. Our studies of this species prove that there is a narrow and broad form, as shown by plates xxii and xxiii ; also, quite a range of individual variation. This is shown by Prof. Whitfield's group of figures (Bull. Amer. Mus., pi. xv), where he refei's specimens varying in form to Olenellus (= Menoiiacis) Vennontana. (893) '1 .wM 168 CAMBRIAN FAUNAS OF NORTH AMERICA. I HUM,. 30. it-^i Quite ii lUiirkt'l vsiriation occurs in two heads from near Swantoii, Vermont. It iiS in tiic j^realer breadth ol" the mar;;iiial rim, as sliowii in flfi'. 1 of phite xvii. Other cliaructer.s of tlie species are jiiven under re iiiarks on tiie {T;enus of wiiicli O. ThowpHitni is the type. FormntUm and lovaliti/. — Middk? (Jambiiaii, (Georgia formation, in the argillaceous shales of Parker's quarry, townshij) of Georgia ; east of Swantoii, oil tlie Dullard farm ; west of St. Albans, in the outskirts of the city J in the massive magnesiaii liaiestones west of l*.irker's(]inirr,v, and also about one and one half miles east of the hotel at Ilighgate Si)ring8, Vermont. Mr. Billings cites the species from Bonne Bay, New- ibundland; L'Anse au Loup, on the north shore of the Sti its nf Belle Isle; and the conglonu'rate limestones of Bic Harbor, on the St. Law- rence Itiver, below (Quebec. (Jlenkllus ASAPnoiDES Emmons, sp. ]'I;ito xvii, li>>.s. 4-S, 10; |)1. xx, lij;.s. 'A, '.Ut,b; )>l. xxv, i\'^. 8. l^lliiitoccphala uHoiiUoidin Eiuiiioim, 1844. Ta^onic System, p. ','1, figs. 1, 2, :{, 184tj. Agriciiltiin- of New York, vol. 1, p. (i'l, ligs. 1, 2, i. Oleiiii'' a8a2)hoi(hN Hull, 1847. I'ii.. N. V.. vol. i, p. '27)i\, pi. Ixvii, iig-i. '>a-c. Idem, Fitch, l(-4t». Trans. N. V. State A;;. Soc, vol. ix, j). e(i,'». JiUqitocejihaltm ui^apiioiilitu Eiumon.s, L'^4y I'roc-. Aiiht. Ahsoc. Advt. Sci., vol. i, p. 18; hlaiiif lsri.">. Aiucr. fii'oL. vol. i, \)t. '2, p. 114, tigs. 1, 'i, ;{; pi. i, tig. 18. ParadojridcH uixiphoidix l^iiiiiioiis, l.-^ii). Manual of Geology, p. ^7, iiaiiio of tig. 70. IJudor till' ligiiic on tlio following page tlio naiiie. is ParadnxldrH mavrovephuliiv, and till' ligmt' is taken tVoiii an Dlciirllui ThoiiijiNoiii (Ijanande, IHiil. Bull. Soe. (ii'ol. d(i Fiance, 2'- isc'i-., t. xviii, p. x!7:?, jil. v, tigM. 4, .5). Oleiidlun anaiilioideti Toi'd, 1,~7I. Auier. .Jour. S.i., lUl sur., vol. ii, p. ;'..!. Idem, 1877. Saiiit! .jouiiial, vol. xiii, p. ~'(ir>. Jdum, 1878. Same J(uirnal. \t)l. xv, p. I'i!). Idem, l88l. Same Journal, vol. xxii, ]>. i.'.O, The history of our knowledge of this trilobite may be divided into two epochs: First, that of the original discovery and (h'S(uiption of the adult form and its connection witii the Taconic controversy; secondly, that of the des(!ription of the embryonic jdiases of its growth ; the first extending over a i)eriod from 1S44 to I8!i() and the second from 1871 to the present time, the period intervening between lS(»()aiid bSTl being one in which little additional information was gained. The material upon whicli this species was founded shows .some of the chara(!ters of the head and thorax. The author gives Hgures of the head and six segments of the thorax of a Itirge individual, a smaller crushed head, atid a fragment of a thoracic segment. The same spe',;i- mens were subse(puMitly tigured in tlie Paheontology of New York, vol. i, pi, Ivii, ligs. 2(i-c, any a description, Dr. Emmons subseciuently obtained a more complete specimen of the thorax, which is tigured on plate i, tig. 18, of his American Geoh)gy. Fourteen segments occur in the thorax and decrease in size and length regularly from the head backward, a feature not observed in the other species of the genus and one that seems to distinguish the species from the closely related 0. Thompsoni. - (894) WA1.C0TT.1 MIDDLE CAMBRIAN FAtTNA. )01ll. of the segments resemble those of Mesonacis Vermoninna in tlieir curvature rather than the strongly recurved jileura' of O. Thomimnii, of the eleventh to th(^ fourteenth segments. The discovery of more i)erfect specimens can alone deter- mine the number of segments and the character of the pygidinm. The second epo<;h in the history of the species we owe to the investi- gations of Mr. S. W. Fonl, who discovei'ed in the limestones at Troy, Mew York, a number of minute specimens showing some of the meta- inorpiioses of the species. Two of i\Ir. Ford's figures I have reproduced, one showing a young stage, where the body is i)artia]ly developed, and the other the mature form; iilustratiotis are also given of two very small heads, figs. 5 and 0, plate xvii. Fig. 5 has a length of four-fifths of a millimtiter, and fig. (i, of 1.75'"'". Mr. Ford calls the spines a; a? the interocular spines ; these are absorbed during tlie development oi' the animal and also to a great extent their continuation up on the head; the surface of the latter. is (Tos.sed by elevated lines corresponding in jxisition to the glabellar fur- rows; they appear to indicate the original segmentation of the head» most of which is lost by absorption during the subsequent development, except on the glabella; the connection between the frontal lobe of the glabella and the ocular somite or segment is beautifully shown. As far as can betletermined, the thorax is not yet developed in either specimen represented by figs. 5 and 6. Fig. 8 shows the great development of the third thoracic segment, and also the interocular spines and genal spines, which are placed so close to each other in figs. 5 and 0. A speci- men figured by Mr. Ford shoMs them separated by a slight crevice. Fig. 8 also shows the tenden<\v of the genal angles to extend forward, a feat- ure so extravagantly develoi)ed in 0. Gilberti. Mr. Ford has discussed the metamori)hoses of the young of O. am- phoiflcs in a minute and able manner, and the reader is referred to his ])iipers (Amer. Jour. Sci., 3d ser., vols, xiii, xv, and xxii) for further in- formation. The geographic range of 0. amphoUles is not yet well determined, owing to the fact that when in a fragmentary condition it is impossible to detect tiie dittei-ence between it and 0. ThompHoni and 0. Gilberti when the latter is also without the thoracic segments. Formation and localities. — Middle Cambrian. In argilhuieous shales at Keynohls's Inn, northeast of ]>ald ^lountain, Washington County, (895) '^'m ■'.y.m 170 CAMBRIAN t'AUNAS OF NOUTIl AMERICA. [uuLi..;',). New York. Mr. Ford lius also found it iu the liiuestones on the ridf^c east of Troy, New York, and also one mile below Schodack Landing, New York. Olenellijs iDDiNGsr Walcott. Plate xix, fig. 1. Ohnellua IddingH Walcott, IHHS. Monographs U. S. Geol. Survoy, vol. viii, j). LM, 1>1. ix, fig. 12. Original description. — "General outline of the head roughly subtri angular, with the length one-half the breadth of the posterior border; strongly convex; the rather narrow rounded riin bordering the anterior margin suddenly becomes thickened and rounded o[)j)osite the eyes, and is extended back in the short, strong, slightly curved, genal spinet;, the narrow posterior marginal border uniting with it at the genal angles. Glabella elongate, narrow, divide«l by lour transverse fui-- rows into Ave lobes; the anterior is round, tumid, and expanded later. ally, while the four ])osterior are narrow, transverse, of equal size, and with their sides parallel ; occipital ring and furrow not recognized ; eyes luuate, situated opposite the central lobes of the glabella. Facial suture in front of the eye unknown ; back of the eye it extends obliquely outward and backward, (mtting the posterior margin about two-tliirds the distance from the glabella to the posterolateral si)ine. •'Thorax andpygidium unknown." A second visit to the type locality of the species resulted in tinding a number of larger heads, but no traces of the thorax or the i)ygidiuni. The most prominent peculiarity of the head is the development of the genal spines, as seen on slabs of limestone from the Groonie District, Nevada, on which they appear, when broken from the Jiead, like uiiiUil valves of a species of Leperditia. From the new specimens we also dis- cover that the occipital ring had a low, blunt point at the center of its posterior margin. Formation and localities. — Middle Cambrian. From a fine-grained. arenaceous shale near the summit of Prospect Peak, Eureka Disiriri, Nevada, and also iu limestone at the south end of the Timpahute ltan;^f. Eastern Nevada, brought in by Mr. G. K. Gilbert (Geog. and (Irol. Expl. and Surv. West 100th Merid., vol. iii, p. 109, section xviii, 2c). Olenellus Gilberti Meek. Plate xviii, iigs. l,la-c; pi. xix, figs. 2,2a-h; pi. xx, figs. 1,1a-?, and 4. Olenellus Gilbei'ti Meek, 1874. (Maiiusci'ii)t. ) Olenvllua Bowelli ^Idtik, lS7i. (Manuscript.) Ohnellua Gilbcrli. White, 1874. Geog. and Geol. Expl. and Surv. West lOOtli Merid., Prelim. Rep. Invert. Foss., p. 7. Olenellus nowcUi. White, 1874. Geog. and Geo!. Expl. and Snrv. West 100th Merid.. Prelim. Rep. Invert. Foss., p. 8. Oknus (Olenellus) Gilherll Gilbert, 187.5. Geog. and Geo]. Expl. and Snrv. West U"'lh Merid., vol. iii. Geology, p. 182. (896) WALCOIT.] MIDDLE CAMBRIAN FAUNA. 171 Ulcnuii {OlcneUim) HowcUl Gilbert, 187r.. Geog. aud Geol. Expl. and Siirv. \V«'st lOOth Merid., vol. iii, Geology, p. 18H. Olrnellus Gilhirti White, 1875. Geog. and Onol. Expl. aud Surv. W«'st 100th Merid., vol. iv, p. 44, pi. ii, figs, '^a-e. Ulciiellus liowelli White, 1875. Geog. and Geol, Expl. and Surv. West lOOIli Merid., vol. iv, p. 47, pi. ii, figs. 4a, ft. OUnMua Gilherti Walcot ' , 18^4. Monographs U. S. Geol. Survey, vol. viii, p. 29, pi. ix, figs. 1(5, 16a; pi. xxi, fig. I'.l. Oltiiiilm Hon Hi Walcott, 1H84. Monograi)hs IJ. S. Geol. Survey, vol. viii, p. *J!), |il. ix, ligs. 15, 15a, b, nnil pi. xxi, ligs. !-',». Ill the original notice of this Hpecics by Mr. Meek, he comi)ai't's it with M€so7iaci8 (0.) Vermontana to show the r(Jad and essentially of tiie same chara(!ter as that ])recedin}X it; the finrow separating tliein is very shallow at the center and inclined obliquely backward at tiie sides; a small node occurs on one examphi at the center of the occipital rinj,'. Eyes elonjfate, narrow, an«l arching- from ojjposite the anter'or ^da- bellar lobe to opposite the occipital furrow. The dorsal furr<.'.vs are narrow, distinctly but not deeply impressed. Fixed cheeks a little ex- l)and('d anteriorly and s(;arcely more than a line in width between tla^ elonfjate palpebral lobes and the doisal furrows, while posteri()rly the.> me]'<;e into the small trian(;ular lateral limbs; frontal lind) variable; it varies in width on different spettimens from scarcely a line to a broad, fattened area between the {flahella ami the anterior marj^ln. Free cheeks rou<,'hly subtriangular iu outline, variable in yidth and in the outljnc of the curve between the jjenal anjjle and the inner margin. The facial suture cuts the anterior niarjjin some distance outside the line of the outer mar<,dn of the glabella and passes oblicjuely inward to the anterior anjult? of the eye lobe; curving around the outei- nuirgin of tliis, it passes obliquely outward to the posterior margin, cutting it midway between the glabellar lobe and the outer margin of the geual angle. Thorax with fourteen segments; axial lobe moderately convex and narrowing gradually to the posterior segment; lateral lobes flattened out to the geniculation of the segments; segn..!nts nearly transverse out to the geniculation of the pleural lobe, where they c«irve backward, terminating iti long slender points; pleural groove broad, well defined, and rian. The species occurs in limestone and argillaceous and sandy shales, and ranges through from 50 to 300 feet of strata overlying a massive belt of reddishbrowu quartzitetl)at is 3,000 feet thick in the Wasatch Mountains. In Nevada. 0. Oilbcrti has been found a^ 'ioche on both sides of the anticlinal arch of (luartzite; on the western side of the Highland Itange. S miles north of Bennet's Spring; in the Groome District, near the south end of Timpahute Range, on Silver Peak, longitude 117° 20' west, latitude .'58° north; and on the summit of Prospect Mountain, Eureka District. In Utah two localities are known: one in thcM-auou Just above Ophir City, in the Oquirrh Range, and the other in T.ig Cottonwood Cafion, Wasat<;h Mountains, one mile below vVrgenta. Tiie sp(>cimeiis brought in from Kicking Horse Lake, British (Columbia, by Mr. (leorgti M.Daw- son, appear to be identical with those from Nevada and Utah. OBSERVATIONS ON OLENELLUS GILBET?TI. '" """SI 'id f lit m "lip Under the title of "Observations on OleneUns HoiceUi" (Monographs U. S. Geol. Survey, vol. viii, p. 32), 1 have attempted to describe the remarkable series of variations observ(Ml in the head of this species (biiing several stages of growth. Additional material has since been obtained, and the principal facts are here brought together. (899) * pr^ !>''lt 174 CAMBRIAN FAUNAS OF NOETH AMERICA. [BULL. 30, Unless otkerwLse ineiitioned, all the specimeiKs are from the same striiliim of rock. ('o:itour of the head. — The smallest specimen of the head observed, fig. ]<•, pi. XX, is L'.o'""' in length, and resembles in its outline the larger head, tig. le, which has a length of 7.o""", which is seen more clearly by comjjar- ing tiie latter with the enlargement of fig. lc=fig. 1. Between tigs. Ic mul U', in size, is the form represented by flg. 3^, which is transversely quad- rilateral in outline, with the genal angles and spines carried forward to form antero lateral angles on a line with the frontal margin of the head; ai.d the geiiici'lrttion of the posterior margin, which is so strongly niitrked in flg. 1, is still further increased to form an angle of nearly ".>()"', which, from its position, might bo incorrectlj* viewed as the true genal angle if the anterior si)ines were broken away or obscured and the course of development of the si)ecies unknown. In fig. Ig the geual sjrines are still more anterior thari in the smaller forms (figs, le and le), and present a transition stage — not considering the size of the head, but the general form — between figs. Ic and Id, or Id and le; the angles of the posterior margin .vx are also more obtuse, and the frontal margin broadly rounded Through the forms represented by figs, le, Ig, 1/j, the modification of these features is very uniform to the normal adult tyjM' of the contour of the head, as shown by fig. It. In figs. Im and T7^, however, which ar«' considerably larger specimens, the angularity of the liosterior margin is a prominent feature, the genal angles being advanced as in the forms before fig. 1?. In fig. 11 the outline is still further diversified by having the angularity of the posterior margin and the position of the genal spine on one side different from the other side. Fig. li is considered as nearly typical of the adult outline of the head as the largest si«ecimen found, and a number of medium size have the same form, and it is characteristic of other species of the genus. The geniculation of the posterior margin is an embryonic character that is singularly ])ersistent in many examples that have otnerwise adult characters. In fig. 36 the adult form of the head of another species of the genu- is shown. The speciiiien represented by fig. 1/is from the south end of the Tini- I)ahute Kaiig'% 1*00 miles south of the Eureka district. It is associated with such form.', as Ic, le, and li, and also with O. IddingHi on the same slab of limestone. It has the genal spines even more anterior than in fig. \d. Wit'i it occurs the form on ])hite xix, fig. 2d, which, in the posi- tion of the glabella, is much like the tyj)ical O. GUbcrti of Meek. One other .specimen of the head that is 3""" in length has the outline of tig. \g, and three others, having a length of 2""", 1.8""", and 1.5°>"', respect ively, have a contoui' as siiown in lig. LV, pi. xvii. (Jlabella. — In the smallest head tli«' glabella is depressed between the large crescent shaped eyes, and the anterior lobe iijjpears to be a link uniting the anterior ])ortions of the two eyes to form a semicircle around the depressed glaUella back of its anterior lobe; in succcehite XX. Comparing with tlie glabella of the adult, it is to b(^ observed that in the younger individuals the glabellar furrows exteuIopnient of the individual nothing is known from actual observation, but, i'iom the iact thai the relative po sition of the eye changes, it is probalde, indeed almost certain, '.hat its direction is somewhat varied, and we know that such is the o-ase in its direction back of the eye when tlie latter is situated on the cheek o: near the glabella. Back of the eye, in all the instances iu which il iias been observed, its direction is slightlj' outward, with a siguioidal eiirv ature to the angle of tin; posterioi' margin, or, in its absenee, to tin; broad (airve denoting the position of the angle about midway liftweeii the dorsal furrov. and the genal angle, figs. Ic, Iq, l/i, and 1/, pi. xx. In the large adult s])ec'iiien its c 'irse was ])i'obably as indicated ity t!ie traced lire in tig. 1/, Mhere it is minh the same as in the genus Ogygia (901) liiiil mn \% .-■'■■ .;•..• I t, •;' .'ill •^JC I ' ' '5.S M \h '■i't'' tn;:'. II 176 CAMBRIAN FAUNAS OF NORTH AMERICA. fn"r I,. 30. or Dicc.llocephalus, and even more so in the cheek, fig'. \c of pi. xviii, if it cut the posterior margin at the angle x, as it does in all known cases in the smaller specimens, ti<>s. 1/t and 1?'. Coiuparin^^ this with tlie direc- tion of the stages of growth shown on figs. \e and \g, wiiere anotlter generic gronp is suggested l)y its Paradoxides-like course, the contrast is very striking. It is stated on p. 34, Monographs United States Geological Survey, vol. viii, that in adult specimens of O. Gilherti and 0. Vernionfana the course of the facial suture is almost directly backward from the eye to the margin. This statement was based on the published figures of the two species. I now have before me the type specimens of (). Gilherti, and I fail to find a trace of the facial suture sliowing on any one of ihem, and their course is not mentioned by either ^Ir. Meek or Di. Wlii't', tlic artist evidently having indicatetl in the drawings his personal views of where they should be placed. In well-preserved speciuiens of O. Thouipsoni the suture back of tlie eye extends outward to the pleural angle, as in O. Gilharti. ?[ode of (lerelopmtiif. — The iiorniid development of a trilobite from tlic earliest embryonic condition with which wc are acquainted to the adult form is marked by the disai>])earance of the embryonic characters, one by one, as the individual increases in size and assunu\s unnv and juore the features of the fully develoi»ed animal, all of which usually takes place, except in size and surface ornamentations, when it is quite small. Tlie retaining of au embryonic feature after the imlividual has passed in size, or in any other character, the stage at which it usually disappears in the regular course of the development of the sjiecies is an excee;!- ingly rare occurvencte, and is unknown to our knowledge, except in the increase in size of the body m certain species, so that in tlieir course of development certain individuals are in fact larger than those of the same species having a greater number of segments in the thorax and being consequently more advanced in development. INF. T.arrande has shown this to be the ease in the (Unehqiment oi' A rcllni.siHa Kdniimhi, Frocfiis (IccoruN, and F. vemisttiH (Syst. Sil. Boheme, i, p. LMkS, 1852), and we have observed it in Triarthrns Bed!, where the relative size, proportional to the development, is very marked; .. g., an individual with thirteen seg- ments in the thorax is 21""" in length, and (uie with sixtecm segments but Hi.")' " long, while the fully grown exaniple of sixteen s*»gm( iit> reaches a length of 53'"'", and some with thiiteen segments are but 7"" in length (Trans. Albany Inst., x; Fossils of the Utica Slate, p. 211, l;sri>). This jteculiarity of growth is shown, in the species mentionee of deveh)pinent. The smallest specimen we now have (it is doubtfully referred to this si)ecie8) is 1.5'"'" in lon«;th; but, owing to its having been exposed to ;itinospheri(! action, tlie details of its surface are not well j)reserved; tlie general form and the j)ronunent eyes, narrow glabelhi, and de- pressed margins an' all that can be satisfactorily determined} these are shown in tig. 2c, pi. xix. The course of d(iveloi)ment would appear to have been from some such form as this througli forms similar to those represented by tigs. Ic, I5, l/(, and li, i)late xx, but we find forms like tigs. Id, 1/', and J// associated with the former forms, in the same pieces of rock, at localities 125 miles distant from each other, and then^ is in each lociility a gradation of tbnn uniting such extremes as tigs. ]/ and 1/. Separating the two ex- trci'ies, as two species, will solve the diflQculty of giving a common origin to such forms ii.s iigs. Ic, 1^/, Ic, 1/, l(j, lli, and 1/ represent, but we capuot obtain evidence to warrant such a separation. JJotli at Eureka and in the Tim])ahute llange, the evidence is strongly in favor of refer- 1 ing all the variable foiiiis of the head to one s|)t'(^Mes. It is observed that tigs. Im, 1/.', and 1/ precede 1/ in the stage of de- elopmeut of the contour of the head, at the same time showing a more accelerated development in the form of the eye. The eye of tig. 1/t is more advanced than that of tig. 1/, while the posterior outline of the liciid is more embryonic in its character. With these examples it is readily conceived that Iigs. !, iis seen in P. ■splno-sit.i. Of all liie species of lii*^ lai tc- genus, /', Kjefulii (Ofversigt k. Svens!;. V.-s.-Akad. Vorhandl. N:o 0, p. 790, faii. xvi, figs. 1. 2 Stockholm, 1871) alone shows the presence of an ocular ridge unit/ing the eye Jiiid tiie :roiit;il livbe of llie glabella (fi,u. -, pi. xx), a feature so inominent in .lie young «»t' (). (illbern, as well hh the small rounded proluberance bi'tween the eyes and the glabella, sliowu in Liuuarsson's fig. ~ of P. Kjerulji. Tin' iailcr character Mr. Ford dis- cov<>r(Hl in the young of (>. n sap ho ides, ^nd noted its rcsoniblanee to tlie same In P. Kjirnlji. The ocular r'dgf, a. teature in .he latter thai is perniamMit, is also present iu the young and adult of (), GUbcrti and in O. ThompKoni. Resume. — The study of I he head of 0. GUberti, prov«ifi , First. That iu certain in(li\iduais of this species tlie existence of eai bryonic features contimi^'s 'ong after thr indiv idnal has reached tin- size at which mu-Ii features are u^ualIy lost in the proccMs of develop ment of the other species of the genus. Secondly. Ttiat, \n individuals otherwi.se develo|)etl equally iu all re spects. some one of tiu'u\ m.iy have a characteristic feature, such as the eye or the geual ar^le i)ear to liavc the remains of ;tn animal that was a]ipr(iiiching extinetion and gradually losinjj it« vital force to .sueh an extent that tlie younj; were unable to de\<'lop to the adult form except in u more or less imi»erfect (lejjree, and, jks a result, retained embryonic features althou;;h having the power to grow to tlu' adult size in only h ('<>iTi]>arative degree enn wo say that it is a cas'' of rever.sioii to the original forms of the genus Of family to which it belongs, as we know so little of the progenitors of the Paradoxi, exclusive of tlic telson, which is quite as long as the body, shows most decided embryonic chariict«*rs in the head, and the third segment of tiie th.orax has a peculiar toiui iothe pleural lobes and is prolonged to a^i extr.ivagant leng;!'. The form of the third segment is not entirely normal, as it liny been 'vowded forward and the pleural (iTO(>v«' depressed. The pieune figured on pi. xix. hgis. 2h and 2i, prob ably belonged to an indivitiual like fig. _ of pi. xxi. -Vnofher sp(»cim«'n, ;'0""' in length, t'xclusive of the telson, pi. xxi, lis I, is e>;>ea' lal'.y a y«>ung soecimen of (Henelht^Thoynpsoni, diHeriu^i ■IS, specieN tii.4n from liie specimen mentioned above The only ivason 1 have f»r !ea\ tng O. Gilherti undei a differtut specific name IS the fact of its haviu'.;: sucU a peculiar and abnormal variation ivi difier ent individuals. If the two specimens vepresenred by tigs. 1 :*iid L* of plate xxi were submitted to a paleonr,oiogi>^t he wtmld be v«-!y apt r.» consider tbetn not only as specitically di,stiJK;t, but perliaps reiev tig. '2 to * subgenus <>( i\ii. 1 ; and i acki'owledge That, in asking th<* student ■&* consider 'IitMu as different ptiases of one t^peci^^s. 1 am requiring htn to accept '■videuce which is e.idy paftially given in ti«»» illustrations of the species; "'If. if lie iins fol!ow<^d •111- 10 the pre- iliiiju pag<^•^ o* Ocsc-'-iption of (). HiUicrtl he may uuderts' .iid why the n^-ad represeW'ed mv lig. 1/of pi. I, ;1N m}" 1a:-'< ;[ 180 CAMBRIAN FAUNAS OF NORTH AMERICA. [BUI,1.30. XX is regarded as specifically coiiuected with that of tig. 1, pi. xviii, or fig. 1ft of pi. XX, and that figs. 1 iMid 2 of pi. xxi are considered to be si)ecifically the same. There are no dittercnces of the bodies of figs. 1 and 2 of i)l. xxi that iirc, essential, except in tlie third segment of the tiiorax, as the broad and narrow forms of the figures are owing largely to the sj)eciiiiens luiviii;,' been compressed in opposite directions. The dilference in the form of thb, third segment is of the same type as that in the genal spines of tlie head. Fig. la, pi. xxi, shows the hesid of iig. 1 natural size. Fig. 2 of pi. xix is evidently the same; also figs. 2a and 2ft of the same plate. Witli tig. 2a of pi. xix the transition to figs. 1ft and 1? of pi. xx is natural, and then from fig. It of pi. xx to ti};s. 1ft, Ic, h/. Id, and If. That tlii.s change is not a direct embryonic developnieyt is shown by the size of the heads and by the fact that it occurs in lieads of nearly the same size, as in the head of fig. 2a, i)l. xxi, figs li, 1/, Iwj, pi. xx, and tig. 2b, pi. xix. H' we do not accept the view that only one sj>pcies is represented, and begin to break up the series, the complications tluit arise are iiiu(;li greater than the acceptance of one variable species, abnormal in its growth, as already described. The spines of tlie head of fig. 2 of ])1. xxi are of the same type a.s those of fig. 2d of pi. xix and l/'of \)L xx. If there is a sjjecific ditfcr eiice between figs. 1 and 2, pi. xxi, it is in the length of the gvnal spines, as we have specimens with the long spines showing the variation in tiic outline of the head from fig. 1/, pi. xx, to a head of the same outline a.s the head of fig. .1, pi. xxi. Ii, fact, tig. I of ])1. xx is more nearly le- lated to fig. 2 of the same jilate, in respect to the strength of tiie .spines, than to the average head of the species. With all the data that 1 can obtain, I think that we have but one species now placed under (>. (ill- berti. Genus OLENOIDES IMeek. O'f'Hoidcs Meek, 1H77. Gcot. Expl. I'orticlli l';ir., \i>l. iv, pt. 1, p. 2.1. Type Paradoxiden f NevadenniH ^lucK, ifiH). Viw. A(;;nl. >i:il. .Sci. I'liila.,v(>l. xxii, p. O'i. The generic des(?rii)tioii is drawn from the type species and thesecuiid speci«^s, (). fi/picaJifi. General outline ovale. Head large, semicircular. Glabella straiglit or slightly expanded in front; marked by three pairs of fuirows in 0. tjipicalis. Eyes elongate. The facial sutures extend obli(|nely ontwaid IVom the anterior base of tiie eyes and cut the frontal margin : pos- teriorly they cut the margin at the |)leuial angle and nin subparaliei to the margin, to the posterior end of the eye. Thorax with eight or more segments ; axis strong and pleural le niilike I'aradoxides, Olenellus, or Dicelloctephaliis. and yet includes in its tlio- liicicses'iiuMits features eoiiimoii to tht' two former genera and. in the eyes 1111(1 lacial sutures back of the eyes, characdcrs found in Dieellocei'iialus. The stratigraphic jiosition of tlie species referred to it, 0. Xevevlensix, 0, ii/pioalis, 0. .^pinonv.s, and O. flanrictiudus, is between the Middle Cambrian (Olenellus) horizon and U])per Cambrian (Dicellocephalus) horizon. The ty]»e sjiecimen of 0. Nevadensis preserves the occijiital segfuient of the head, the eight thoriicic segments, and about two-thirds of the livv.idiiim. The seconxi<1fiif Xeradcii^in Alcok, 1870. Pioc. Acad. Nat. Sci. Pliilad., vol, xxii, p. 62, Idem, 1877. Gcol. Ivvj)!, F(•r^i(^^ll Piir.. vol, iv, y». 'ili, ])1. i, fiy;. f). The original desciiption appeared in IS70 and was reprinted in 1877, the only change being in the proposal of the generic name Olenoides in event of the species proving to belong to an undescribed genus. The later description is as ibllows : " Of the thorax, eight of the posterior seuiiients are jireserved. These siiow the axial lobe to be much de- pressed, and ibont as widt; as the lateral ones, exclusive of the free re- eurve'inoiit mid cv tends ui»ward and baiikward. Tlic spine on the eij-lith .sc^Mncnt is jno- longed and extends back (piite a distance beyond tlie extremity of tlic terminal spines of the i)yf,Mdinni. An individnal lo lonj; sliows tlic s])ine with a lcn;?th of 10""". Tiie spine is ernsiicd down on the IkmIv . but appears to have been slender and cnr\('), from Point Levis, Can ada, where it was associated with Upi)er Cambrian fossils, and it may lu^ that Avhen entire specimens are found some of the species referred to Dicellocephalus, from the same bed and locality, will prove to belong to this genus. Formation and lovaUiy. — Middle Cambrian. Tn a light pinkish-colored shale above a belt of limestone resting on the shales carrying OleneUun Oilberti, Pioche, Nevada. Olenoides spinosus Walcott. I ij I Mi mi Plate XXV, figs. 6,6 a. Ogygiaf sj^inosa Walcott, 1885. Monograplis U. S. Gool. Survey, vol. viii, p. 63, pi. ix, lig. 2'2. The orighial specimen preserves only the central portions of the head within the free cheeks. The glabella resembles that of Ogygia, so a I)rovisional reforetice was nuide to that genus. The discovery of 0. iyplcaUs gives the generic reference and a sec- ond specimen of the sanui parts of the head from the arenaceous shales at the same relative geologic horizon at Pioche aflords details not shown in the Eureka specimen. The glabella is expanded more in front and the posterolateral limb is presi'ived ; no tracje of the occipital spine is shown, but this was probably carrie I- a im WAIIOTT.] MinnM", rAMHRTAX lAirXA. 185 Formation and loralitien. — Middle ('nmbiiiiii. At tlio biiRo oC tlio Sccii't ('iinoii shiilo, it) Si'crrtOaiioii, I'^iirckii Dictrict, Nt'Viidii ; also, at rioche, Xt'vadii, in arciiaceons sbulc iiiterbedUcd iu iirgilluceoiiH mIisiIijj Niitional Musoiun collect ion. OLENOIDKS? FLAaBIOAUDUS Wliitti. I'liito XXV, li|n. 4. DircllocephahiH ? Jlanr'uaiithin Wliilc, IH7I. (ivAx^. and ficol. F.\\)]. luut Surv. WcHt lOOtli Mcrid., I'rcliiii. Uip, liivrit. t'oss., |i. 1'^. Jihiii, 1875. Siiiiio reiuirt, vol. iv, pt. 1, |i. t'pi», |p1. iii, lii^. t*ii,l), Oriffinal description. — " Pyj'idiiiincontractodjfsin-Hliiipod; lateral lobes viu'}\ coiisistiiifjf of three segments directed bacikward; tlie inner one of oacli sid(^ l.vinjj- (dose to the dorsal furrow, iieiirly parallel with the axis of the body or converj^inji^ a little posteriorly, and be('oinin<>' obsolete upon each side of a small, but comparatively wide, sloping' border that extends around the posterior end of the axial lobe. "The middle pair of segments commences at the dorsal furrow of each side res])ectively, near the anterior end of the pygidinm, bend abrn])tly, and extend backward parallel with the lirst, and prcjject beyond the liorder as converging j»osterior spines. The third and outer i)air of segments conimenc anteriorly at the dorsal furrows, where they are very narrow, extcMid outward a little, then (Mirving abruptly backward tliey lie parallel with the others and form raised lateral margins of considerable but unecpuil width to the pygidiimi, and thenc(! they extend posteriorly as an outer pair of converging spines. Axis promi- nent, especially at its ai)e\, where it terminates in a moderately distinct angle, about one-quarter wider anteriorly than ]>osteriorly, well defined by the nearly straight dorsal furrows, and marked by five or six dis tinctly defined segments, which cross it almost transversely, but with a slightly sinuous course. "Length of the pygidium along the median line, 7"""; greatest trans- verse diameter, 9'""'. "The collections contain only the ])ygidium of this species, and I have therefore referred it doubtingly to I)iveUoceph((ius, although it niight perhaps, with e(iiial projiriety, be referred to Aiitphion. It has a general resemblance to the i)ygidium (»f J>. mdnniJioiN Billings, and a still closer resemblance to J).? Corux Billings, from the Quebec group of Canada. '■'■ Position and locality. — Strata of the age of the Quebec group of Canada. Schellbourne, Scliell Creek range, ]S^evada." The species is referred to the Quebec group ; but without a better knowledge of the stratigraphy than we have, and also of the associated fossils, it is difficult to locate the exact horizon, and 1 suspect that further investigation will place it in the Cambrian. The generic reference is made entirely on the form of the pygidium. (911) 8* 'A '\ 'i 1 ■ 1 1 :'li IMAGE EVALUATION TEST TARGET (MT-3) /. m/. 1.0 I.I s If Ilia ^^'- IIIIIM 1.8 IL25 i 1.4 1.6 V] * m v: '/ /A Photographic Sciences Corporation 23 WEST MAIN STREEV WEBSTER, NY. 14580 (716) 873-4503 x< iV ■^ :\ \ T L

xtremity, and marked by six annulations, exclusive of the terminal ones. Lateral lobes very moderately convex, and marked by four divided ribs on each side, each terminating in a strong and proportionally long marginal spine; cen- tral area of each rib depressed, forming a flattened groove, extending to the base of the marginal spine. Borders of the ribs elevated, the anterior one strongest and prominent, gradually widening from its ori- gin to the margin of the shield; posterior border narrow and rounded, separated from the next succeeding rib by a sharply-dei>ressed, narrow groove. This peculiar form of rib gives to the shield an appearance similar to the groining of a Gothic arch. Margin of the shield sur- roundearts of the organism, require a distinct generic name." By comparing the figures of Olenoides Marconi, pi. xxvi, flgs. .'), ort, with those of pi. xxix, figs. 2, 2a, the types of Dicellocephalus Walisatch- enais and D. gothicus, the generic identity is evident, although the pleural grooves on the anchylosed segments of the pygidium are not known to be present in that of 0. Marconi. The spe(Mfic relations of O. WahsatcheriHis are with O. qnadriccps, as has been mentioned unoBterior margin nearly straight, with the lateral angles terminating in abruptly pointed extremities, so short as scarcely to project as far backward as the posterior margin of the second thoracic segment. Glabella depressed nearly even with the BnU. 30 13 (919) 194 CAMBRIAN FAWN-AS OP NORTH AMERICA. (iiiiM.. no. I 1 1 If ,'1 ■ I • i fli cheeks, about two-tliirdH as long sih i\w entire heuU, and Itetween one third and one-fourth the breadth of the stune behind, but narrowint; forward to its subtrunoated anterior end, and separated front the cheekH on each side and in front by a shallow furrow ; occipital furrow moder- ately well defined, and continued as rather deep broad furrows along the posterior margin of the cheeks out nearly to the points where the facial sutures cut the margin; lateral furrows not clearly defined in the si>ecimens, but apparently consisting of four pairs. Facial sutures di- rected at first, for a short distance, forward from the inner anterior end of each eye, then curving gracefully outward as they extend forward, until near the anterior margin of the head, where they are a little wider apart than the distance between the eyes, but again curving rather ab- ruptly inward, so as to reach the anterior margin nearly on a line with each eye; posteriorly these sutures extend at first outward, nearly at right angles to the longitudinal axis, from the posterior end of eacli eye, and then curve gracefully backward so as to intersect the pos- terior margin between one-fourth and one-third the distance from the lateral angles, inward toward the glabella. Eyes rather depressed, slightly arched outward, and separated from each other by a space somewhat less than half the entire breadth of the head, and placed less than their own length in advance of the posterior margin, and about once and a half their length behind the front margin of the head ; visual surfaces narrow, and not showing any lenses under a good magnifier. " Thorax with its length bearing the proportions to that of the head, of 79 to 52, and to its own breadth, of 79 to 107, being very slightly wider near the middle than in front, and narrowing posteriorly, with gently convex lateral margins, from behind the middle to the pygidiuui. Axial lobe depressed, narrow, or only about two-thirds the breadth of each lateral lobe at its anterior end, and narrowing regularly with straight sides posteriorly ; segments thirteen, nearly or quite straight, and each with a small node or prominence at each end. (In some speci- mens thest) nodes seem to be wanting, while in others they do not exist on all of the segments.) Lateral lobes depressed or nearly flat ; pleuree almost transverse or arching slightly backward to near the extremities, which are abruptly pointed; each with a well-defined furrow, which commences small near the anterior inner end and widens and deepens for about half way out, and then narrows and becomes more shallow, so as to die out before reaching the lateral extremities. "Pygidium subsemicircular, being rounded posteriorly, with a nar- row, slightly flattened border, and somewhat rounded anterior lateral extremities; length bearing to that of the thorax the proportions of 30 to 79, and to that of the head of 30 to 52, with a breadth of not quite two- thirds of that of the head ; axial lobe equaling more than two thirds the length, narrow, depressed, and showing more oriess distinctly about five segments ; lateral lobes much depressed, nearly twice as wide at the anterior end as the middle one, each with about three segments, which (920) WAIiCOTT.) MIDDLE CAMBRIAN FAUNA. 195 curve a little backward and become obnolote before |>n88ing upon the narrow, smooth border ; segments each provided with'u comparatively large longitndinal ftarrow, corresponding to those on the pleunv. <'Entii« surface apparently smooth, excepting fine radiating strite on tbe anterior and lateral portions of the cephalic shield that are scarcely visible without the aid of a magnifier. "Whole length, 1.60 inch ; breadth of thorax, 1.07 inch; breadth of cephalic shield (somewhat flattened by pressure), about 1.12 inch; length of thorax, .70 inch ; length of pygidium, .30 in(;h ; breadth of pygidium .60 inch.'' The very short genal spines of the head and also the peculiar curva- ture of the posterior margin between the facial suture and the spine, as shown in Mr. Meek's type specimen, are owing to the breaking away of t(ie outer marginal rim and outer side of the spines with it, and the ]>08terior marginal rim is crushed and bent out of shape and also partly broken away. Twenty entire specimens show the spines and marginal rim as In the figure given by Dr. White and as in the figures on plate xxvii. Formation and locality. — Middle Cambrian. House Range, Antelope Springs, Utah. Ptyohopaeia Adamsi Billings sp. Plate xxvi, figs. 1, lo-c. Conoetphalite$ Adamai BilliDgs, 1861. Geology of Vemiont, vol. ii, p. 950, ds- 355; Pamphlet (1861) republished (186.'>) in Pul. Fohh., vol. i, p. 12, fig. 15. Idem, 1863. Oeol. Canada, p. 28(i, fig. 294. Conocephalitet armoaug Billings, 1861. Geology of Yerroont, vol. ii, p. 952, fig. 3.58. Idem, 1865. Pal. Foss., vol. i, p. 15, fig. 18 ; Geol. Canada, p. 286, fig. 297. Original description. — "Head broad, semicircular, moderately convex; glabella oblong-conical, nearly two-thirds the length of the head, the front obtusely rounded or somewhat straight, the anterior angles nar- rowly rounded, the sides nearly straight from the anterior angle to the neck furrow, just in advance of which is the widest part. The neck farrow well defined all across; the glabellar furrows indistinct; the dorsal furrow is well defined all round the glabella. The cheeks are moderately tumid; a line drawn across the glabella about the mid length would pass through the eyes. The distance of the eye from the dorsal furrow is equal to the greatest width of the glabella; the eye ap- pears to be very small. The margin in front of the glabella is equal in width to about one-third the whole length of the head ; it is bordered by an obtuse, narrow, elevated rim, just within which is a groove which is more deeply impressed on each side than directly in front of the gla- bella, there being at this place a gently convex elevation, resembling that which occurs in Barrande's species, G, Sulzeri and C. Coronatus. The ocular ridge is well defined where the surface is preserved, but is (921) m 196 CAMBRIAN FAUNAS OF NORTH AMERK^A. (huli.:h). I ': 1^ i rarely visible iu the Huudstoue cuhIh. MonI of tliu HpceiinciiN arc (lin tinctly carinate »loiig the iiiedian line of the glabella. " It is possible that there may l>e a niediau tubercle ou the neck seg loeut, but none of our speuiuieus have this part suiUcieutly well pre served to show it. *' The following are the diineiisioDS of a specimen of the average size: Length of head, five lines; length of glabella, three and one fourth lines; greatest width of glabella, two lines; width of glabella at front, one and one- fourth lines; distance of eye from side of glabella, two lines. ^« Dedicated to the late Prof. C. B.Adams, State geologist of Vermont. " Formation and locality. — Highgate, Vermont, in the Potsdam group, about a mile east of the Highgate Springs." On assembling a large number of specimens of the head of this si)ecieM from limestone, arenaceous and argillaceous shale, and arenaceous lime- stone, we find that it is even more variable than as described by Mr. Bil- lings and that it includes the form given by Mr. Billings as C. arenonus. On plate xxvi figures of the head are given to show variations. The frontal limb, between the glabella and margin, varies in breadth and, in the smaller heads, is very narrow; the frontal rim also varies very much in thickness and breadth. li\ sfiecimens from a purplish- colored limestone, the maceration of the test, prior to mineralization, ap- pears to have gone so far that nearly all the outlines of the glabella, frontal limb, and rim were lost by the compression accompanying the consolidation of the sediment. In the collections of the Museum of Comparative Zoology, Cambridge, Massachusetts, there is a matrix of a nearly entire individual of this spe- cies IS")"* in length, from Parker's quarry, and the U. S. Geological Sur- vey collection includes the greater part of a specimen 40^"' long. From these we obtain a description of the thorax, pygidium, and iiree cheeks of the head in addition to Mr. Billings's description. The free cheeks are narrow and terminate posteriorly in sharp spines that reach back even with the fifth segment of the thorax. Thorax with sixteen segments, narrowing gradually' to the tenth se;;: nient and then more abruptly to the pygidium ; axial lobe about three- fifths the width of one of the pleural lobes; segments narrow, rounded on the axial lobe, and flattened ou the pleural lobes; the pleural lobe is flattened about one-half the distance from the axial lobe to its outer margin and then bent dow^nward, and each segment directed slightly backward; pleural groove broad, well defined, and extending nearly to the end of the segment. Pygidium small ; axial lobe short, obconical, and marked by two or more rings; lateral lobes showing the pleural grooves corresponding to the axial rings. Surface finely granulose under a strong magnifier (Tolles's f-incb triplet). (922) WALcaix) MIDDLE CAMBRIAN FAUNA. 197 > spines f-incb Formation and localitieg.—MidiWe Oambrian, Georgia Formation. Friinlclin County. Vermont. East of Higbgate Springs the species rouges through the purpliHli and reddish magnesian limestone and up into the argillaceous shales, a total distance of over 1,600 feet. It occurs at the same relative horizon on the Bullard farm east of Swanton, and also at Parker's quarry in the town of Georgia; also, in the conglom- erate lime-stones of Bio Uarbor, below Quebec, on the St. Lawrence River, Canada. Ptyohopabia Tguobr Billings. Plate xxvi, fig. 3. ConovephalUe$ Teuoer BillingM, 1H61. Geology of Vermont, vol. ii, p. 9S1, fig. 366; Pamphlet (1861) ropiibliHbed in Pal. Foaa., vol. i, p. 13, fig. 16, .< <; Qeol. Canada, p. i286, fig. '295. Original description. — " Head semi-oval ; glabella conical, con /ex, well (letlued all round by the dorsal furrows, about two-thir^^ the v. hole length of the head, widest just in advance of the neck turrow. sides gently convex, froit tly rounded, neck furrow well defined all a oss ; ))OHterior furrows commencing at about one-half the length ot tlie gla- bella, and running inwards and backwards nearly to the neck furrow and one-third across ; median furrows curved backwards, and extend- ing one fourth across; anterior furrows short; ocular ridges well de- tilled; front margin one-third the whole length of head, with a well- (lefiued groove running across, in front of which there is an elevated marginal rim, which rises with a flat slope upwards and forwards; the groove across the margin is situated at about one-fourth the distance from the front of the glabella to the elevated edge of the rostrum ; the cheeks are moderately tumid ; the neck segment is well developed, with a small median tubercle scarcely the fourth of a line in height, which in some specimens seems to be absent altogether. "Thorax of 13 or 14 segments; axis strongly defined, cylindrical; side lobes about one third wider than the axis. '' The pygidium is very small, being scarcely one-sixth the length of the thorax. The only specimen in which it has been observed attached to the thorax is not sufficiently well preserved to enable me to descnbe it in detail. "The following are the measurements of two of the specimens: Length of head, 4^ lines; length of glabella, 3 lines; width, just in advance of the neck furrow, 2^ lines, and at one-third the leu;:th from front margin 2 lines. " In a specimen consisting of the thorax and pygidium whe whole length is 6 lines, of which the pygidium occupies apparently a little less than 1 line. Width at first segment, 5^ lines; width of axis at same place, 1^ lines; width at anterior margin of pygidium, about 3 lines. "The position of the eye is not shown in any specimen that I have 8eei>, but, from the width of the portions of the fixed cheeks which (923) ■•'■"■SI ■^1 IT m t H m 'i n .i Ml: i ■r t 198 CAMBRIAN FAUNAS OF NORTH / ilERICA. lBUIX.30. remaio, it must be distaut from the dorsal farrows nearly the width of the glabella. *' This species appears to be closely allied to the one above cited from Shumard's paper, so far as the characters of the glabella are concerned. As, however, the proportions are a little different, I shall dispose of it as above until I can have an opportunity of submitting a specimen to Dr. Shumard. " Locality and formation. — One and one-half miles east of Swantoo. in Vermont, in the elates of the Potsdam group." Mr. Billings describes an entire specimen, but does not figure it, and we have been unable to obtain any more than the head exclusive of the free cheeks. The most marked difference between the head and that of P. Adaimi is in the form of the frontal limb. A comparison with specintens of P. Billingsi, from Texas, shows it to be a distinct species. Forma f '>on and locality. — Middle Cambrian, Georgia Formation. About 1^ miles east-northeast of Highgate Springs, Vermont; also, in the con- glomerate limestones at Bic Harbor below Quebec, on the St. Lawrence River, Canada. Ptychoparia Vuloanus Billings. Plato xxvi, figs. 4, 4a. CoHOoephalitet I'ulcatius Billings, 1861. Geology of Vermont, vol. ii, p. 952, fig. 357; Puiuphlet IStil, republished (1865) in Pal. Foas., vol. i, p. 14, fig. 17; Oeol. Canudu, 18K.3, p. 286, fig. 296. Original description. — "Head broad, moderately convex; glabella obtusely conical, with the neck segment triangular and extended back- wards in the middle ; neck furrow not extending across, being inter- rupted by a stroug carina which runs along the median line ; dorsal furrow aU round, but not sharply defined. Front margin about one- third i\\e length of whole head, with a projecting rim, and a traqsvorse groove situated two-thirds the distance from the front of glabella. Gheeks moderately convex; ocular ridge well defined; a line drawn across the head a little in advance of the mid-length of the glabella would pass through the eyes ; the latter distant from the glabella at least half the whole lefigth of the head. No indications of glabellar furrows visible. " Length of head, four and one-third lines ; of glabella, including the backward projecting angle of the neck segment, three lines ; width of glabella just in advance of neck furrow, two and one-third lines; dis- tance of eye from glabella, two and one- fourth lines. " This species differs from G. Adamsi in the character of neck fur- rows and in the greater proportional width of the glabella. ** It was found along with C. Adamsi in the same beds.'' (924) WALCOTT.] MIDDLE CAMBRIAN FAUNA, 199 This species varies in tlie 8ba])o of the ghibella, occipital segment, and frontal limb so much that I am inclined to consider it a little m(»re than a variety of P. Adamai or P. Teuoer, as it is intermediate to them iu many of its characters. An illustration is given of an extreme form and also of one that approaches more nearly to that of P. Adamsi. It is associated with P. Admnni at ail the localities where it has been found. Formation and localities. — Middle Cambrian, Georgia Formation. Franklin County, Vermont, Parker's quarry, and also one mile east of Highgate Springs. Ptychopahia miser Billings. ' ' Plate xxvii, fijj. 2. Conocephalites mUer Billing^, 1861. Geology of Veriuoat, vol. ii, p. 950, fig. 354 ; »1ho in pamphlet. Idtm, 1863. Geology of Cauada, p. 286, fig. 293. Idem, 186.'). • Pal.Fo88.,vol. i,p. 12,ttg. 14. Original description. — " Glabella elongate, conical, very convex, most elevated at about the mid-length, slightly narrowed at the neck segment, widest in the middle, narrowly rounded in front, well defined all round by the dorsal furrows. Neck segment strongly convex and bearing a short broad-based spine directed upwards and backwards. Neck fur- row extending all across; the posterior glabellar furrow well defined across, forming an obtuse angle backward iu the median line ; median glabellar furrow also running across, but not so strongly defined as the posterior; anterior furrows extending one-third across. "Length of glabella, two lines; width in the middle, about one-half the length. " There is no described species to which this one bears any close re- lation, on account of the peculiar character of the posterior and median furrows running quite across the glabella." In looking over the collection of the Canadian Geological Survey with Prof. J. F. Whiteaves, we found a more perfect example of the head than that figured by Mr. Billings, and I was kindly permitted to havo a tigure made of it. The frontal limb, fixed cheeks, palpebral lobes, and posterolateral limbs are shown in addition to the i)arts described by Mr. Billings. Formation and locality. — Middle Cambrian. In limestone, associated with fosails characteristic of the Georgia Formation of Vermont, I/Anse au Loup, on the north side of the Straits of Belle Isle. Ptychoparia quadrans H. & W. Plate xxix, tigs. 4, 4a, b. CrepicephaUs f {LogaHeUiia) quadrans Hall & Whitfield, 1877. Geol. Expl. Fortieth Pur., vol. iv, J). 238, pi. ii, figs. 11-13. Compare P. Adamai aiiJ P. Kiiigi. Original description. — *' Form of entire body unknown. Glabella and fixed cheeks together broadly quadrangular, about four-fifths as high (925) if c V-'it 'M, *.■., i. 11 »■-: ^'^ 200 CAMBRIAN FAUNAS OF NORTH AMERICA. [BULL. 30. W M. as wide and quite uniform in many individuals, very depressed-cou- vex or quite flattened, as occurring on the surface of the shale in which they are imbedded; glabella distinctly conical, moderately tapering above the occipital furrow, and broadly rounded in front; marked by three pairs of distinct transverse furrows, which are directed ob- liquely backward from their outer ends ; the posterior pair almost or quit« meeting in the middle, the others shorter and situated at almost equal distances from each other. Occipital furrow well marked, propor- tionally wide and shallow ; occipital ring narrow, not well defined. " Fixed cheeks very broad, nearly two-thirds as wide as the glabella, depressed-convex; frontal limb short, the broader and inner part of nearly the same width ; sides of the limb in front, wide, and slightly rounded at the anterolateral angles ; posterior limb wide at its junc- tion with the glabella, and rapidly narrowing outward, being a1)ont once and a half as long as its greatest width ; ocular ridges slender, aut very distinct, rising from the anterior angle of the eye and uniting with the glabella near the anterior furrow, forming a slightly curved line parallel with the marginal furrow of the head. "Facial sutures directed inward from the anterior margin of the head, to the eye- lobe, behind which they are directed outward and backward to the posterior margin of the head, at an angle of about forty degrees to the occipital line. "A form of movable cheek found associated in considerable numbers with the glabellas, and corresponding in size and character, is narrowly triangular, the posterior extremity terminating in a short, blunt spine, slightly curved; inner angle strongly notched for the reception of tbe eye-lobe, and the outer margin bordered by a thickened, rounded rint, which gradually increases in width to the base of the spine. The facial suture corresponds to the margin of the fixed cheek above described, and, on the under side, the anterior border is prolonged in the form of an acute process, to extend along the anterior border of the frontal limb. "The pygidium associated with the above specimens is minute, trans versely subelliptical in form, most strongly rounded on the front border, with a wide axis terminating obtusely a little within the posterior mar- gin. The axis is marked by five rings, exclusive of the terminal ones. Lateral lobes convex, marked by three or four divided ribs, (exclusive of the anterior single one. " Surface of the head and cheeks marked by fine anastomosing lines, radiating from the eye and front of the glabella." This species, as far as we know its structure, is closely allied to Pty- choparia Kingi, and, with the latter species, to P. Adamsi. They are the representatives of the same specific type in the distinct localities at which they occur. P. quadrata is associated with Olenoid^s Wahsatchensis in a dark, shaly argillite. (926) WALC0TT.1 MIDDLE CAMBRIAN FAUXA. 201 The figure of the head on pi. ii, fig. 11, Geol. Expl. Fortieth Par., vol. iv, is that of an unusually elongated specimen, and not the form that is most abundant. We give one that is the average form of a number of heads found at the type locality. Formation and localities. — Middle Cambrian. Above Gall's Fort, north of Box Elder Caiiou, and one mile below Argenta, in Big Cottonwood Cafion, Wasatch Mountains, Utah. Ptychopaeia Housensis, n. apt Plate XXV, fig. 5. Head small, transversely quadrilateral exclusive of the free cheeks ; moderately convex. Glabella rather small, of almost uniform width from the posterior margin to the rounded front ; furrows shown only by a posterior pair; occipital ring strong and bearing a short small spine that extends obliquely' upward and backward ; occipital furrow of mod- erate depth and continued out as a strong groove on the lateral limbs; dorsal furrows broad and well defined. Fixed cheeks wider than the glabella;, palpebral lobes small; ocular ridges strongly defined; frontal limb concave, of medium width, and rising to a strong frontal rim; postero lateral limbs short. Surface finely granulose. j. Free cheeks, thorax, and pygidium unknown. This peculiar little liead is associated with Ptychoparia Kingi and Asaphiscus Wheeleri, and, while we have over one hundred perfect spec- imens of these two species from the same bed, but one fragment of P. Housemis has been found. This is so strongly characterized by its form and occipital spine that I do not hesitate to give it a specific uame. Specific name derived from the House Range. Formation and locality. — Middle Cambrian. House Eaiige, Antelope Springs, Utah. Ptychoparia Piochensis, n. sp. Plate xxvi, figs. 2, 3a, b ; pi. xxviii, figs. 1, la-«. x -I General form ovate, moderately convex, usually much depressed by being flattened in the shaly matrix. Head transverse, semicircular ; frontal margin comparatively narrow iu young individuals, becoming broader and more flattened with the increase in size of the animal; posterolateral angles prolonged into slender spines. Glabella of medium size, truncato conical, and marked with three pairs of short glabellar furrows that increjtse in size and also in obliquity to the central axis on the larger heads , occipital groove shallow and rounded downward from the base of the glabella and up- ward to the moderately strong occipital ring ; a small point or node occurs at the center of the latter. Fixed cheeks of medium width ; they merge in front into the broad frontal limb and posteriorly into the (927) 'as ^i?.'^' WW 202 CAMBBIAN FAUNAS OF NORTH AMERICA. [BULUaO. elongate, narrow, postero-lateral limbs ; palpebral lobes small ; ocular ridges well defined and terminating nearly at the front of the glabella; frontal limb comparatively' narrow in the young and broader in the older and larger specimens. Thorax with 19 segments in two specimens 30""" and 40"*"' long, re- spectively ; another specimen, 18""" long, shows 17 segments ; the seg- ments are nearly transverse, except at the geniculation on the pleural lobes, where the falcate extremities bend slightly backward ; axial lobe moderately convex ; pleural lobes flattened half-way out and then curved downward to their margin ', pleural groove of medium width and cou- tinued well out towards the extremity of the segment. Pygidinm small, semicircular ; axial lobe with 3 or 4 segments ; lat- eral lobes small and marked by furrows indicating about 3 united seg- ments. Surface apparently smooth except on the frontal limb and free cheeks, where fine, irregular striae radiate towards the margin. The large number of segments in the thorax, 19, is a marked peculiarity of this species, t^e usual number of segments in the gonus being from 13 to 15. The expansion of the frontal limb with the increase in size is also very suggestive, as, in the adult, we have the broad, compauu late limb, and, in the young, the narrow limb with an elevated outer margin ; a variation that would be given as specific if the intermediate forms were absent. The small pygidium resembles that of Ptychoparia Emmrichi (see Syst. Sil. Boh6me, vol. i, pi. xi, fig. 4), except that it is proportionally smaller. Formation and locality. — Middle Cambrian. In an argillaceous shale, at the (JLisholm Mine, on the southwest slope of the Ely Mountains ; also, on the western slope of the Highland Eauge, 8 miles north of Ben- net's Spring, Nevada. . . Ptychoparia sp. ! Associated with OlentUiis G'dherti in a gray, granular limestone, at Piocbe, there is a species of Ptychoparia that is closely allied in the head parts to P. Adamsi. The material is too imperfect to determine satisfactorily, at present, its specific relations. Ptychoparia ! Prospectensis Walcott. - Plate xxvii, Ag. 5. Ptychoparia f Proapectenais Walcott, 1884. Monographs U. S. Geol. Survey, vol. viii, p. 46, pi. ix, flg. 20. The general outline of the head is moderately convex, semicircular, the width being about twice the length. The glabella is subconical, truncate in front, and marked by three pairs of short, slightly impressed, glabellar furrows; occipital ring dis- tinctly defined by a narrow, lightly inii)ressed, occipital furrow; fixed cheeks broad, of equal elevation with the glabella, and extending be- (928) WALCOTT.I MIDDLE CAMBRIAN FAUNA. 203 row: fixed youd it anteriorly, the space between them on the oroad A'ontal limb being occupied by a small swelling or boss that, but for the slight trans- verse dorsiil furrow between it and the glabella, might be mistaken for u continuation of the latter ; the eye lobes are comparatively large for a species of this character and occupy a prominent position on the outer margin of the cheeks, a distinct ocular ridgo crossing the latter from the anterior margin of the eyes to the dorsal furrow on a line with the front of the glabella; the lateral limbs are narrow, rather short, and slo))e rap- idly downward back of the eye-lobes ; frontal limb broad at the center, narrowing in front of the fixed cheeks, and bordered anteniorly by a not very distinctly defined rounded margin. The facial suture curves a little inward in front of the eye and appears to terminate on the front line somewhat in advance of a line passing through the center of the tubercle in front of the glabella ; behind the eye it extends obliquely outward and backward to the posterior margin of the head, outlining an elongate triangular postero lateral limb. Under a strong magnifying power the surfifce is seen to be finely granulose (see p. 32). Free cheeks, thorax, and pygidium unknown. Its associated species are mentioned in the introductory remarks of this bulletin. Formation and locality.— ^Middle Cambrian. Mountain shale band of the Prospect Mountain section, on the east slope of Prospect Peak, Eureka District, Nevada. Ptychopabia trilineata Emmons (sp.). Plate xxvii, fig. 1, la-c. Atopa trilineatua Emmons, 1844. Taconic system, p. '20, fig. 1, pi. ii, fig. 3. Idem, 1847. Agrl. Rep. N. Y., vol. i, p. 64, fig. 8; pi. xiv, fig. 3. Idem, 1849. Proc. Amer. Assoc. Adv. Sci., vol. i, pp. 16, 17. Idet 1855. Amer. Geol., vol. i, pt. 2, p. 115, pi. i, fig. 16. Atopa trilineatua Haldemau, 1848. Amer. Jour. 8ci., 2d ser., vol. v, p. 107. Atopa triliiuatua Barrande, 1861. Bull. Soc. G6ol. de Franco, 2" s^r., t. xviii, p. 26J», pi. v, fig. 1. Cahimene Beck 11, 1847. Pal. N. Y., vol. i, p. 252, ;>1. Ixvii, tigs. Aa-i: Idem, 1848. Amer. Joar. Sci., 2d ser,, vol. v, p* 322. Calymene Beckil Fitch, 1849. Trans. Agrl. Soc. N, Y., vol. ix, p. 865. Cahimene Berkii Walcott, 1879. Pamphlet in advance of vol. x, Trans. Albany Inst., p. 23. Atopa puiictataa Emmons, 18.59. Manual of Geology, p. 88, fig. 71. Atopa punciatua Barrande, 1861. Bull. Soc. G6ol. do France, 2" 8<r., vol. ii, p. 33. Conocephalitea trilineatua Ford, 1873. Amer. Jour. Sci., 3d ser., vol. vi, p. VXi. Conocephalitea (Atopa) trilineatns Ford, 1875. Amer. Jour. Sci., 3d ser., vol. ix, p. 205. Triarthrua trilineatua Miller, 1877. Cat. Amer. Pal. Fosh., p. 223. Cnnocorjiphe Foul, lii80, Amer. Jour. Sci., 3d ser., vol. xix, p. 152. ... This trilobite has an interesting htstory that connects it with the Taconic controversy. First charac/terized by Dr. Emmons as typical of (929) ■ mi *i!n W 1: 204 CAMBBIAN FAUNAS OF NORTH AMERICA. (BULL. 30. tbe Taconic system, it was considered by Prof. Hall the same as the Triarthrus Benki of the Utica slate, and not of importance in estab lishing a different geologic horizon for the Taconic slates. It was not until Mr. Ford, in 1871, published a list of the fossils known to him from the conglomerate limestones east of Troy, N. Y., that the question was satisfactorily settled, a fact overlooked by the writer in prepariiij[r a list of the synonyms of Triarthrus Becki in 1879 (Trans. Albany Inst., vol. X, p. 23). The original specimens figured by Dr. Emmons were fragmentary and very much compressed, and the figures of the head and three segments of the thorax of the best specimens are not so good as the original specimen that is now preserved in the collection of the American Mu- seum of Natural History, New York, a figure of which is given on plate xxvii, fig. 1. Subsequently (Araer. Geol., p. 115, 1855) Dr. Emmons descnbed a much more perfect specimen, as follows: ''Crust granulated, cephalic shield semicircular, with its anterior and lateral edges turned ifpwards ; posterior angles rounded, facial suture beginning at the outer angle of the cephalic shield and runs nearly par allel with the anterior margin to the middle lobe, when it turns at a right angle and runs parallel with that lobe; eyes undistinguishabU', body con)])osed of seventeen or eighteen rings, narrowing very gradu ally to the caudal extremity ; pygidium a fiat expansion of the crust, and is provided with a single ring; axis narrower than the lateral lobes; rings seventeen, each of which is separated by a groove about as widt; as the rings. Axis armed by a row of short spines ; lateral lobes pro vided with a row of tubercles or prominences along the median line ; margins of the rib groove run parallel as far as the tubercle, when they diverge; tubercles become obsolete towards the tail ; caudal shield very small and provided with one or at most two rings." The figure which we reproduce on plate xxvii (fig. Ic) is that of the specimen described; it is crushed, and if the same liberty was taken in making the drawing that was used in that of the first figure we cannot place much reliance on the details. The whereabouts of the specimen Is unknown to me. Dr. Emmons afterwards considered this specimen as belonging to a distinct species, A.punctatus; but, from the fact that the original does not preserve the outer shell and that from the parts preserved we can not judge of its specific distinction, I have considered them as belong ing to one species. The first type specimen shows an ocular ridge and traces of the direc tion of the facial sutures the same as in typical species of the genus Ptychoparia. The generic name Atops preceded that of Ptychoparia, but it was not until years after Ptychoparia had been thoroughly Hton«,aH8fK!iatc(l with OleneUuH Oilherti^ beneath the areiiaceouM shale carrying Olenellut OHherti and 0. Iddingsi, West Bh>pe of Prospect Mountain, Eareka DIh- triot, Nevada. Genns OBYOTOCEPHALUS n. gen. (dpvKT<>c, fiirrowt^d. 1111)1 Kr^uAf/, huuecimens of the head and pygid- ium of a small trilobite that, in its generic and family relations, a]) proaches Parabolina of the family Olenidte. The combination of char- acters shown in the head and pygidium serve to distinguish it A>om any generic form known to me. Type Oryctocephalus primus. OBYOTOCEPHALUS PRIMUS n. Sp. Plate xxix, iigH. 3, 3a. Entire head as restored by the union of the free cheeks to the central portions of the head, transverse subsemicircular. Glabella elongate, quadrilateral, sides parallel, front broadly rounded and, in some speci- mens, showing a slight indentation midway; surface marked by four transverse furrows that terminate in little pits within the margin of the glabella; a shallow de])ression unites the pits on each side within the margin, and there is on some glabellas a very shallow depression run- ning obliquely backward from each pit to the axial furrow ; the trans- verse furrows uniting the pits are strong and arch a little backward at the center ; anteriorly a shallow pit occurs a little back of the antero- lateral angles of the glabella that opens out into the axial furrows; the occipital furrow is represented by the posterior pair of pits and connect- ing furrow, and the strong occipitJil segment is united to the glabella at each end within the axial furrows; axial furrows strongly defined. Fixed cheeks nearly as broad as the glabella ; they narrow slightly in front and broaden out posteriorly into the short posterolateral limbs; frontal limb practically obsolete ; a narrow raised margin bonlers the front of the head ; palpebral lobe narrow and with a deep groov«! be- tween it and the fixed cheek; a narrow ocular ridge crosses the fixed cheek from the palpebral lobe to the axial groove opposite the small an- terior depressions on the side of the glabella. Free cheeks elongate, convex, bordered by a narrow rounded rim that extends backward as a short spine; visual surface of eye broken away. (936) Hi'': WAI.COTT. 1 IflDDI.K CAMBRIAN FAUNA. 211 Tlionix unknown. AH80ciateygidium apparently Hlightly giauulo.se. This trilobite is so distinct in its character that, beyond referring the (Tonus to the Olenidae, there are few couipariHons to make Nave those iiinted at under the generic description. Formation and locality. — Middle Cambrian. In limeHton(> just above the quartzite, east of Pioche, Nevada. Genus PR0TYPU8 n. gen. T.v|)o Protypui Eitohoooki Whitfield. The only entire example of an individual of this genuH is the type of the typical species, and, until more is known of other species referred to it, the description of the species gives the generic characters. PEOTYPrS HiTOHCOCKI Whitfield (sp.) Plate zxxi, ^k- 4. AngeHna HUoheooki Whitfield, 1884. Bull. Amer.Mus. Nat Hist., vol. i, 148, pi. xiv, fig. 13. Original description. — "Body ovate in outline, largest across the base of the head and gradually narrowing bdiind ; distinctly trilobcd lon- gitudinally. "Head broad, semicircular in outline, being about twice an wide across the base as the extreoie length from the front margin to the pos- terior side of the occipital ring. Glabella proportionally large, with parallel sides and rounded front. Surface convex and apparently des- titute of any glabellar furrows. Frontal limb narrow in front of the glabella and bordered by a narrow rounded rim. Fixed cheeks ])ro- portionally broad, crossed in front of the eyes by a distinct ocular ridge, which is curved and runs nearly parallel to the margin of the head. Lateral limba large, triangular, and extending nearly to the origin of the cheek spines. Eyes large, reniform, and the palpebral lobes flattened. Occipital ring narrow and divided from the glabella and fixed cheeks by a narrow groove- Movable cheeks elongate tri- angular, curved on the outer margin, moderately convex over the central area, and projected backward at the -posterolateral angles in short spines. Facial suture passing a very little outward in its course from the eye to the anterior margin, which it cuts nearly at right angles to the border ; behind the eye it passes obliquely outward and back- (937) li « . 'U T^ 212 CAMBRIAN FAUNAS OF NORTH AMERICA. [BOLL. 30. mm .:vj'!: ward with a slight curvature to just within the cheek spine, forming a very broadly triangular lateral limb. " Thorax nearly once and a half as long as the head, consisting of twelve segments, and nearly twice as wide at the anterior as at the poa- terior end ; strongly trilobed, the axial lobe forming one-third of the width anteriorly, but rapidly tapering backward ; at the twelfth seg- ment its width dees not exceed one-fourth of the whole. Axial lobe convex, the segments well marked, narrow and rounded, separated by broad grooves; pleura straight, direct and flattened for nearly two- thirds of their length, from which point they are rapidly narrowed to a point, which is not recurved, but which is a little back of the central line of the rib. Surface of the i)leura broadly channeled, the furrow occupying nearly the entire width of the rib and extending to the ex- tremity. "Pygidium small, semi-elliptical, and transverse, about four times as wide as long, and marked by three furrows, both on the very small axis and on the lateral areas. Axis terminating within the posterior margin of the plate. " Surface of the test smooth. " The generic relations of this trilobite are not exactly those given by its author to the genus Angelina, but they are more nearly like them than of any other described. The general form and proportions are very sim- ilar, as is also the general appearance; but in the head parts it differs principally in the possesion of very distinct glabellar furrows, which is in direct opposition to the generic diagnosis, and the eyes are larger than those of the typical species. In some lights the specimen figured seems as if it had possessed two pairs'of glabellar furrows,^ but they are so very unsatisfactorily defined that I have chosen rather to consider them as ab- sent. The great difference, however, is the nature of the furrows of the pleura and the pointed extremities of these parts. In the A. i^edywicld the furrow is narrow at each end and broadest and angular at the genic- ulation, which is near the middle of the length, while in this one the furrow is broad at the inner end of the pleura, and retains its breadth and depth for the entire length, only narrowing as the extremities of the ribs are narrowed, while the extremities of the ribs cannot be fairly said to be bent backward to any degree. These points of difference, although considerable, I have not deemed of suflflcient importance to constitute a distinct genus, rather considering that the typical species was followed too closely in the original generic description." After reviewing the character of the genns Angelina and those of the species under consideration, I am led to differ with Prof. Whitfield and to consider the diffferences of generic importance. Briefly enumerated, thej' are: The presence of strong ocular ridges. I The author probably meant ooulur rw^M. (938) II . Kjular ridges, WALCOTT.] MIDDLE CAMBRIAN FAUNA. 213 the difference in the type of the pleural lobes of the thoracic segments, and the pygidium of Angelina, which has a spiuose margin. In a second species found at Parker's quarry, P. parvulus, very faint glabellar furrows are shown in a natural mold of the glabella. The only specimen yet known to me of P. Hitchcocki is the one de- scrib' by Prof. Whitfield, and now in the American Museum oi y^tural History, New York. Formation and locality. — Middle Cambrian, Georgia Formation. Par- ker's quarry, town of Georgia, Franklin Cmmty, Vermont. Pkotypus senectus Billings. Plato xxxi, lij»8. 2, 2a-e. Balhjurua senectus Billings, 1861. Geology of Vorinont, vol. i', ji.9o3, figs. 059, 360. Painpblet (1861) republished (1865) in Pal. Foss., vo;. i, p. 16, 1863. Geol. Canada, p. 266, figs. 298 a, 6. Compare Bathyurns parvulus Billings, 1861, Geol. Vermont, vol. ii, p. 953. Original description. — "Glabella subcylindrical, clavate, strongly con- vex, one-fourth wider at the front margin than at the neck segment, sides nearly straight, front obtusely rounded and presenting a strong convex elevation, neck furrow extending all across, three pairs of gla- bellar furrows represented by small but distinct and obtuse indenta tions in the sides. Fixed cheeks, rather strongly convex. Eyes of mod erate size, semicircular; a line drawn across the head at about one third the length of the glabella from behind would pass through them, and they are distant from the side of the glabella about the width of the neck segment. The front of the neck is surrounded by a narrow border which appears to be flat; thfu appefirs to be some evidence of a spine on the neck segment. " The pygidium found iu ^lie same fragment of stone with one of the specimens of the glabella of this species is iu all general characters that of a Bathyurus. It is semicirculiir, convex, axis cylindrical, strongly ••onvex, terminating behind with rn abruptly rounded descent, six an- nidations, the first three or four most strongly defined. The lateral lobes have four segments each, separated by strong rounded furrows; there is a narrow entire margin all round, with a distinct groove inside, which appears, however, to be interrui)ted at the end of the axis. "The dimensions of the most perfect specimens are as follows: "Glabella, length three and one-half lines; width at neck segment one and one-half lines, at the front two lines; distance of the eye from the side of the glabella one and one-half lines. The eye appears to be about three-fourths of a line in length. "Pygidium, length three lines; width at anterior margin five and one half lines; width of axis one line. ^^ Locality and formation. — Anse an Loup, on the north shore of the Straits of Belle Isle. Limestone of the Potsdam group." (939) ■■i.v.T:J,-l:{ '■'J ■•£':•;■•!! iW'i m m ■*:f '.''A ■-^■ri ^■M 214 CAMBBIAN FAUNAS OF NOBTH AMEBICA. [BULL. 30. In the more arenaceous and calcareous layers of the upper portion of Parker'8 quarry the heads and pygidia of this species are quite abuu- dant, and, on comparing them with the figure and description of P. se- nectus, we place them under that species. The figure and description given by Mr. Billings require the pres- ence of short obtuse glabellar furrows, and these we find on two specimens ; ten other specimens of the head do not show them. lu other particulars the head appears to be the same, and the associated pygidium is similar to that found with P. seneetua; and, as they are from the same relative geologic horizon, I prefer to place the Yermont species under P. aeneotua rather than to make a new species for its recep- tion. The species Bathyurua parvulua is associated with P. aenectua at UAnse au Loup, is almost identical in appearance with some specimens of the head of P. aeneotua as found in Vermont, and it is, as yet, uncer- tain whether the latcer should be referred to P. aenectua or P. parvulm. The condition of preservation is the cause of the two forms in the Yer- mont rocks. P. parvulua is placed as a variety of P. seneotu^y as I am unable to clearly understand the type of P. parvulua. In studying broken fragments of trilobites it is difficnlt t4> determine generic, much less specific, relations ; but, from a study of the type of the genus Bathynrus, I do not think we can refer any known species from the Middle Cambrian to that genus. In some respects this species approaches quite closely to Corynexochm apinuloaua Angelin (Pal. Scan., p. 59, p]. xxxiii, figs. 9, 9a); but, until we have a more complete description and better figures of that species, it would be hazardous to make a generic identification. Formation and loealitiea. — Middle Cambrian, fltet rgia Formation . Par- ker's quarry, town of Georgia, and one and one half miles east of Swan- ton, Franklin County, Yermont ; also, on the Labrador coast, as men- tioned above. Genus SOLENOPLEUBA Ai «elin. Solenopleura Augelin, 1852. Pal. Scan., p. 26. SOLENOFLETJBA NANA Ford. Plate xxvii, fig. 3. Solen&phura ^ana Ford, 1678. Amer. Jonr. Soi., Sdser., vol. xr, p. 126. Original deacription, — <' The largest and best-preserved specimen con- sists of a nearly perfect glabella and the greater portion of the fixed cheeks, and is but two lines in length. The glabella is neatly four-flftbs the total length of the head and is especially characterized by its great relief. It is obtusely conical, slightly widest behind, and is well defined aU aroaud by the dorsal furrows. In a specimen two lines in length its (MO) WALCOTT.] BODDLE CAMBBIAN FAUNA. 215 highest point is nearly one and one-half lines above the base of the fixed cheeks. It is marked on either side by two or three faint furrows. The fixed cheeks are notably convex, bat their relief does not exceed one-third of that of the glabella. The eyes are sitnated slightly in advance of the mid-length and are connected with the front of the glabella by an obscure ocular fillet. The distance from the eye to the glabella is nearly equal to. the width of the glabella at the mid-length. The front margin is narrow and is bounded by a feebly convex rim, inside of which there is a narrow furrow which gradually deepens on either side of the median line in passing outward. Between this furrow and the glabella there is a somewhat angular ridge which widens in passing outward to the sutures. '< The course of the facial suture is nearly the same with that of Solenopleura brachymetopa of Angelin (Palseontologia Scandinavica, pi. xix, fig. 1), but is directed more inward in front of the eye. The neck farrow is continuous all across. The exact form of the neck-segment cannot be made out, owing to the damaged condition of all of the speci- mens at this point. It is seen, however, to be less elevated than in the majority of the species, not rising above the surface of the fixed cheeks. The entire surface is covered with a tine regular granulation." Specimens in the United States Geological Survey collection show that the occipital segment rises towards the center to form the base of a short spine that projects backw^ard and upward to the base of the tumid glabella. In a head T*"*^ long the furrows of the glabella are shown very distinctly. Formation and loeality. — Middle Cambrian on the ridge east of the city of Troy, New York. Oonglomerate limestone, Genua BATHrURISOUS Meek. Bathyuriaous Meek, 1673. Sixth Ann. Bep. U. S. Oeol. Snrv. Terr., p. 484. Bathyuriscus was proposed by Mr. Meek at the end of the description of Bathyurm t Raydeni in event that the latter species was found to be non-congeneric with Bathyurus extans, the type of the genus Bathyurus. Mr. Meek says : " If further comparisons show it to be generically or subgenerically distinct from all of the groups mentioned, as t believe it to be, it may be designated by the name Bathyuriscus.^^ Having found that two other species are generically allied to B. Hay- deni and distinct from any described genus, I refer them to Mr. Meek's genus; and from the three species, Bathyuriscus Haydeni, B. producta, and B. Howelli, the following description is drawn : General outline ovate. Head medium size, semicircular. Glabella Htr£ right or slightly expanded in front, marked by three or four pairs of glabellar furrows. Byes elongate. The facial sutures cut the anterior margin of the head a short distance each side of the line of the greatest expansion of the glabella, and extend obliquely iuwMd to the anterior (941) 111 i 1 H »l iW n h M ' :» • ! ■ ai 216 CAMBRIAN FAUNAS OF NORTH AMERICA. IBULL.80. bases of the eyes; encircliDg the latter, they extend obliquely outward, cutting the posterior margin so as to leave a narrow elongate lateral limb. Free cheeks unknown. Thorax with from seven to nine segments; axis strong; pleural lobes well defined ; pleural groove broad. Pygidium semicircular ; axis strong and crossed by several furrows ; lateral lobes marked by the extension of the furrows crossing the axis. Hypostoma of B. producta irregularly ovate; broadest a little forward of the center ; posterior marginal rim raised ; a strong sulcus extends around inside the rim ; muscular scars well defined. In many respects the head is similar to that of the genus Olenoides; the thoracic segments recall those of Ptychoparia, and the pygidium might be taken for that of a species of Bathyurus, or perhaps Ogygia. The general assemblage of characters points to a generic type distinct firom any known to the writer. The geologic rangs of the genus is from the Middle to the Upper Cam- brian. Bathyuriseus produeta is associated with Kutorgina pannula, Olenoides typiealis, and Ptychoparia PioehemiSy &c., in a band of shale 2,000 feet below a typical Upper Cambrian or Potsdam fauna, such as B. Haydeni is found with in Montana. The intervening strata between the two specifcs iu the Highland Eange, Nevada, are massive limestones. (See Highland Range section, p. 34.) Bathyubiscus Howelli n. sp Plate XXX, figs. 3, 2a. General form ovate. Entire form of head unknown, but from the parts preserved it appears to have been semicircular. Glabella clavate, expanding in front of the second pair of glabellar furrows; posteriorly the sides are subparallel to the occipital segment ; the posterior pair of glabellar furrows are directed obliquely backward nearly to the oc- cipital furrow ; the second pair are less obliquely inclined backward, and the third pair penetrate directly in, one-third the distance on each side. Occipital furrow well defined ; occipital ring rounded and rather strong. Eyes large, lunate, the extremities close to the glabella. Fixed cheeks very narrow; postero-lateral limbs narrow elongate; frontal limb narrow, slightly convex, and expanding but little in front of the glabella. The facial sutures cut the anterior margin and trend obliquely in to the anterior end of the eyes ; encircling the large palpe- bral lobes, they extend outward from the posterior ends of the eyes and out the posterior margin of the head well out towards the genal angle. Free cheeks unknown. Thorax with eight segments. Axial lobe convex, tapering very grad- ually from the anterior segments to the pygidium ; each segment is well defined and arches slightly forward ; pleural lobes moderately convex; the segments curve gently backward from the genal angl« labella decidedly depressed and the niargiif of the head in front of it first convex and sloping forward into a deep transverse mesial furrow, then rising in the form of a convex margin to the front. The mesial lobe of its pygidium is also proportionally longer, and the free margins of the same much narrower and less flattened and alate. It probably only forms a subgenus under Bathyurellus. From AsapJius, with which it agrees in general form and proportions, it differs in its decidedly con- ical, well-defined glabella, without lateral furrows or lobes, the extended and transversely furrowed character of the anterior margin of its head, its less arcuate eyes placed more remote from the glabella, and partic- ularly in having nine body segments, instead of only eight. As in Asaphus, its pleurae are distinctly furrowed, but they are more pointed than is usual in that genus, though not falcate. Its surface is smooth. " The generic and specific characters will be given in full, with illus- trations, in Lieutenant Wheeler's Report. " Several American species with a similar depressed, conical glabella, without traces of lateral furrows or lobes, have been described from more or less complete specimens of the head, under the name Conoceph- alites. It is evident, however, from its smaller number of body seg- ments, large pygidium, and differently formed plural grooves, that Asaphiscus is entirely distinct from that group." From reading the descriptions of the genera Batbyurus, Bathyurellus, and Asaphiscus, I considered that the two latter genera had been sepa- rated on specific rather than generic characters (TM'enty-eighth Ann. Rep. N. Y. State Mus. Nat. Hist., p. 94, 1879), but now that I have ex- amples of the typical species of Bathyurus {B. extans) and Asaphiscus (A. Wheeleri) before me their generic differences are readily appreciated. The pygidium of Asapljisgu^ is identical in ch^rscter with thflt of B^thy- (946) 220 CAMBRIAN FAUNAS OF NORTH AMERICA. [BL'LUSO. \ t i 1 »!! " ' 'I i i; urns, and from the pygidium alone the reference would be to Batbyuru8. The head, however, shows strongly marked diiferences, as mentioned by Mr. Meek. Witli Bathyurus it is more difficult to decide. Mr. Billings gives as a distinction between Bathyui-us and Bathyu- rellus that the latter has a conical or pointed glabella without traces of glabellar furrows, while Bathyurus has a subcylindrical glabella, rounded in front and marked by obscure furrows, " the pygidium of which also difters in not being strongly convex, in having a shorter axis, and iu general a wider border." Another marked diffei-ence between the two genera is in the configu- ration of the frontal limb; it also occurs between Bathyurellus mX Asaphiscus; this, together with the differences in the pygidium, sti ..s to distinguish the two latter. When reviewing the Potsdam fauna, the relations of the genera Bathyurus and Bathyurellus will be discussed and figures of the typ- ical species given. AsAPHiscus Wheelebi Meek. Plato xxxi, figs. 3, 3a. ■ Bathjfurellut (Aaapkiaous) Wheeleri Moek, 1873. Sixtb Ann. Rep. U. S. Oeol. Snrv. Terr., p. 485, foot-note, 1872. AaaphisciM IVheeleri White, 1875. Geog. and Gcol, Expl. and Surv. West lOOth Merid., p. 43, pi. ii, tigs. 1 a-f. The description of this species by Mr. Meek has already been given under the genus Asaphiscus. Subsequently Mr. C. A. White described the species from the type specimens as follows : "Body oblong-ovate in outline; surface smooth. Head depressecl convex ; front margin regularly rounded ; posterolateral angles ab- ruptly rounded, without cheek spiues; exterior margin bent shortly upward all around, producing a raised border of considerable width, and also a rather deep linear depression, or groove, parallel with that border and between it and the remainder of the cheeks. Glabella coni- cal, much wider behind than in front, depressed; space between its anterior end and the marginal groove about equal to the width of the raised marginal rim in front of it ; outline well defined by the narrow dorsal furrows ; sides nearly straight ; anterior end abruptly and pos terior end broadly rounded, without lateral furrows, or at least they are hardly discernible ; occipital furrow shallow, broad, but somewhat dis- tinct and uniform, extending entirely across the glabella, and continuous with furrows similar to itself that extend to the posterolateral angles of the head ; the latter furrows lie i)arallel with and near to the pos- terior margin of the head, giving that margin also a raised border, somewhat like the one upon the exterior margin. Eyes comparatively small, crescentic, situated nearly opposite the mid-length of the gla' bellft; and nearly equidistant from it and the posterior margin, (946) WAUX>TT.] MIDDLE CAMBRIAN FAUNA. 221 " Thorax Iiaviug nine segments ; its length not quite so great as that of the head ; axis broadest anteriorly, more strongly convex, and about one-third narrower than the lateral lobes are; segments extending Htraight across the lobe; lateral lobes depressed, their greatest con- vexity along the middle ; pleurte bluntly pointed at their outer ends, the points not being directed very strongly backward ; their inner ends 80 joined to the axial segments that they have the appearance of lap- ping a little upon them just inside the dorsal furrow ; grooved, the jjroove being deepest about mid-length, where the outer and inner l)ortion8 of its front border meet at a distinct but very obtuse angle ; j;rooves extending from the dorsal furrow nearly to the extremity of tlie pleurae, where they disappear. "Pygidium somewhat semicircular in outline, distinctly trilobate; segmentation indistinct, so much so in some of the specimens that the surface appears nearly as plain as that of an Aaaphm, but the seg- mentation is usually more distinctly shown upon surfaces from which the crust has been removed; axis prominent, especially at its distal end, where it terminates abruptly at the inner edge of the broad mar- ginal border; segments of axial lobe eight or ten; lateral lobes much depressed, a little wider than the axial lobe at the anterior end, and narrowing to an incurved point at the end of the axis; the whole exte- rior margin having a broad, flat border of nearly uniform width through- out ; the under surface of this border marked by fine, somewhat irregular, longitudinal striae, such as are usually seen upon corresponding parts of Asaphus. ''The largest specimen in the collection is about seven centimeters long. "These specimens are the same that were used by Mr. Meek in his (lesciiption of this species, and upon which he also based his genus Amphiscus." ' All the specimens are more or less flattened by compression; but from a few that show portions of the original convexity it is proven to have been about as in the genus Bathyurus. The strongly marked border of the pygidium also arises from the compression of the doublure up against the upper surface. In an uncompressed specimen the slope from the central axis to the margin is unbroken by any marked line. Formation and localities. — Middle Cambrian. House Range, Antelope Springs, Utah. An identical form of pygidium also occurs at Pioche, Nevada, associated with Olenoides typicalis. Genus DOETPYGE Dames. Dori/pyge Dames, 1883. China, Richthofen, vol. iv, p. 23. It was not until the last pages of this report were put in type that I had the opportunity of reading Dr. Dames's description of the genus (947) 222 CAMBRIAN FAUNAS OP NORTH AMERICA. [kULu 3a m i; Dorypyge and his reference of JDikellooephalus quadriceps and D. gothicun of H. & W. to Uiat genus (China, Bichthofen, vol. iv, p. 24). On pages 187 and 189, 1 have placed the two species under the genuH Olenoides while waiting for proof of the character of the border of the pygidium of the genus. I have very little doubt of its being spinous, and if it is so the species described by Dr. Dames will probably fall within its limits, and the genus Dorypyge be placed as a synonym of Olenoides. In the event of Olenoides Nevadensis being generically distinct from J>orypyge Riehthofeni Dames, then Olenoides typicalis, 0. Mareoui, 0. spinosus, 0, Levis, 0. flagricaudus, O. expansus, 0. quadriceps, and 0. Wahsatehensis may be referred to the genus Dorypyge. It is hoped that this question will be settled during the present year by the acquisition of large collections of fossils from the typical localities in Utah and Nevada. (948) DESCRIPTION OF A PTEROPOD CAMBRIAN. FROM THE UPPER PTEROPODA. Genus MATTHEVIA Waloott. Matthevia Waloott, 1885. Amer. Jour. Sci., 3e in different shells that vary in outline. The shell thins out at the ed^v and is not thick over the exterior of the interior chambers, but between .lem a connecting mass of shell unites the sides and gives strength and solidity ; a section cross- ing the center of the shell at right angles to the preceding shows a solid shell to the outer chamber, where it gradually thins out to the margin. The positions of the two inner chambers var,\ in relation to each other, as may be seen in the figures, from subpaii^Uel to widely divergent; the chamber that is more at right angl^ss !> the aperture than the other is usually larger and is always prominent, while the oblique chamber is sometimes filled up by shelly matter and only the outer portion remains; both chambers are usually flattened on the inner side and more or less expanded where they enter the large outer chamber. The septum cross- ing the inner chambers is thin and varies in shape with the form of the chambers; it is usually slightly concave-convex, concave towards the outer chamber, and marked, usually, by a raised scar of varying char- acter, as is shown in the figures; the septum is usually a short distance from the outer chamber, l""*" to 4°"". The substance of the shell is calcareous, and in thin sections appears to be vesiculose, as in figs, le, If, of plate xxxiii. (950) WAunn,] tTtftOtOD FROM ThE UPPEfe CAMBRIAN. 225 Surface marked by undulating lineu of growth parallel to the margin of the aperture, a few radiating lines UHUuUy on the sides, and several floe papilltiB arranged in lines that cross each other at right angles on some shells ; on others the papillte are arranged in lines parallel to the lines of growth and without reference to the order of those in the ad- joining lines; the interior surface is covered with a fretted surface brought out by depressed, irregular, inosculating lines; this surface varies in force and character, and some shells are almost smooth in- side ; a narrow, smooth space extends all around the margin of the in- side of the aperture. The associated opercula vary in form and outline ; the shell is calca- reous, concavo-convex, rising to a blunt point more towards one end than towards the other ; from this point, which is the center of the con- centric undulations of growth, narrow, radiating undulations extend to the margin. Surface with concentric and radiating undulations; fine inosculating lines subparallel to the concentric undulations and flue papilla) on the spaces between the inosculating lines ; interior surface convex, smooth, or showir ?; the undulations of the outer surface ; at the center, corresponding to the apex of the outer surface, a small round Hcar appears to be indicated on some specimens. There are two forms known to me that correspond in a measure to this: one is that figured by Eichwald (Lethea Koss., pi. xl, fig. lOo-c*) as Hyolithes paradoxodtia, which appears to be the cast of a portion of the outer chamber and one of the conical inner chambers ; it may be, however, only a superficial resemblance. The second was discovered when examining the type of Metoptoma anomala Billings (Pal. Foss., vol. i, p. 89), in the collection of the Geological Survey of Canada. I found it to be the cast of the chamber of habitation of some species of Matthevia. It may be that of M. variabilis, but it is impossible to iden- tify it from the specimen. It was found in a bowlder of limestone at Point Levis, Canada. Formation atid locality. — Upper Cambrian. Limestone resting on Potsdam sandstone, one mile northwest of Saratoga Springs, New York. The species is associated with Cryptozoa poriferum Hall (Thii ty-sixth Adn. Kep. N. Y. State Mus. Nat. Hist., description of pi. vi, 1884), Pla- tyceras minutismmim Walcott, Ptychoporia {L.) calcifera Walcott, Dicel- locephulus Hartti Walcott, and 1). speciostis Walcott. Bull. 30 15 (961) imi Jlil * ii J ' i: r: m n PLATE I. Fig. 1. Ethmophtllum'profunpom 1. Enlargement of a portion of a transverse section of specimen in which the growth appears to have been in layers. Collection U. S. National Mnsenm. la. Outline of the section from which fig. 1 was enlarged. lb. Enlargement of a portion of the section shown by fig. 36 of plate ii. The vesiculose stracture is well shown. Collection U. S. National Mu- seum. lo. Secciou of solid stem. Natural size. Collection U. S. National Museum. 88B (962) 84 n. 8. OEOLoo-.cAL iiaavEY 84 > in which National f plate ii. tional Mu- 1 Museum. BOLLETIN N'O 3J l-L I 1(1 hi ,S*»'.-' ■^PO^GiOZGA « , ^ d; ll JIMJ t'f , il I'l I ■ft t ' t ■ PLATE n. Paga Fig. 1. ARCHiEOCTATHi. ' T , tticUS 73 1. Transverse section *.ype specimen now in the Museum of the Geo- logical Survey of Cii da. la. Longitudinal section of 1. At "a" the growth within the cup, spoken of in the text, is shown. The elongate body, " b," is probably a foreign body introduced into the cup. Fig. 2. Lkptomitus Zittku 89 2. View of the typo specimen. Natural size. 2a. Enlargement of a portion of 2, between the dotted lines. Collection U. S. National Museum. Fig. 3. ETHMOPHYLLUM PROFTJNDUM 84 3. Portion of a cast of the interior of the outer wall, showing the openings in the septa. Collection U. S. National Museum. 3a. View of the cup of a small specimen. Collection U. S. National Mu- seum. . 3b. Longitudinal section showing the depth of the cup and the vesiculose character of the space betwt.^n the walls. An enlarged view of the lower portion of this figure is shown on pi. i. Collection U. S. National Museum. 230 (956) Ur n.zi.or.'^.Ai.Biii'vzi fCLLKTIN NO, SO I L. fPi^H^i:iil/ wlm?f '^if[ :t(T i I H » H M I 4 ^H s <■ 1 K |.'-£ ^ w % 1^ r SPONGIOZOA « « *'ii (i^ 1 -' I 11 l:lk^i PLATE III. Page. Figs. 1,2. Arooaiooyathus Atlantious 73 1. Tranaverae section of apecimen from L'Anae an Lonp, Labrador, en- larged to abow the irregular openings. Collection U. S. National Museum. la. Longitndinal section showing more regularity in the arrangement of theskeleton than in the type apecimen, pi. ii, fig. la. Collection U. S- National Mnaeum. lb. Longitndinal section of a apecimen fr pa Silver Peak, Nevada. 2. Longitudinal section of specimen from silver Peak that shows still more regularity in the interior structure than either la or lb. Collection U. S. National Museum. 2a. Tranaverae section of fig. 2. Pig. 3. Abch^ocyathus Billingsi 3. Transverse section of a small specimen. Collection U. S.' National Museum. 3a. L iigitudinal sectiou showing the central cavity, transverse septa, etc. The outer walla are mostly worn away. CollectionU.S. National Museum. 3b. Enlargement of a few transverse septa, showing the irregular vertical septa, pore openings in the septa, and the spicula-like pieces in the interaeptal spaces. 3e. Enlargement of the spicula-like bodies in the onp and interaeptal ■paces. 834 (960) 74 C B QtOLOGlCAL irjKVET 1 '■rTLLETlM i;0. 3J PL. lU O'Mm i ^^1 Hi ■ 'if^ i if •'' !^ •■■a. i^'l. SPJXGiOZOA i'W •'I'wr* p m'l li ■w ji' [ .,. ;!M 1 ;■ .1 ' II I ■■ I -1 I t i 1 1.1 »■ l':m :\:f PLATE IV. Fig. 1. Ethmophyllum Whitneyi 1. Enlargeniout to two tliaincterH of one of the type speoimenH. Colleotion U.S. National MiiHenui. la. Enlargement of Mie outer Hinf'are to lOdiaineterH. Collection U. 8. Na- tioiial MuHeuni. lb. Longitudinal motion of a Hpeciuien ^bowing the vemcuIoHe inner wall, whicb, whtn the outtr wall and septa are broken away, gives the form described by Mr. Metik n^; K. yraoUia. Collection U. S. National Mu- seum. Ic. Transverse siction showing +he structure mentioned of fig. 1ft still more clearly ; also, the septa and poriferous outer wall. 37 septa. Col- lection U 8. National llusenni. . Id, le. Two transvuiso sections of a very small Hpecimeu, in which the walla and septa are tbickcniMl. y, Trnnsverae section, l..")""" in diameter, showing eight septa. Collec- tion V. 8. National Museum. \g. Similar section to 1/', with 14 septa. The two sections represented by tigs. \il, \e, indicate irregular growth, and 1/, \g, the uninterrupted, natural growth of the s]H>cies. Collection U. 8. National Museum. \h. A largin- transverse section, with .')8 septa ; numerous partitions b jtween the septa, the outer ]>oriferons wall, an In ^ ,^f;;* ^Ufl «i • ■ "f;: yjB i^B- ■' .''^ffi '■ . :''i^41L *■ ^Ji 1 ;\302;a ^ -llfi ' ^i ii. i ^l (' ■ m K .! ■j'S' PLATE V. Fig. 1. Ethmophyllum Rrnssklakkicum Fftge. 86 la. 16 lo Id. 1. A nearly perfect specimen, sbowiog the summit and the outer poriferous surface. Collection U. S. N^^tioual Museum. A speciiuen witli portions of the outer wall removed, so as to show the septa and the poriferous surface of the inner wall. Collection U. S. Na- tional Museum. Transverse section showing 12 septa and the pores of the inner and outer walls, enlarged. Collection U. S. National Muiteum. Transverse section of the upper end of lo, with 18 septa. Collection U. S. National Museum. Transverse section, where the walls and septa are thickened by addi- tional layers. Collection U. S. NatioPbl Museum. le. Enlargement of the outer poriferous surface. If. Drawing of the type specimen, by Mr. S. W. Ford. The poriferous sur- face in worn off on the raised portion. I am not satisfied but the dis- sepimeiits are of accidental origin. There are about 20 septa in the transverse secti' >n of the specimen. Collection S. W. Ford. Fig. 'i. Ethmophyllum rarum 2. View of the only specimen that can be referred to this species in the col- lection of the Geological Survey. The outer surface is entirely re- moved. Collection U. S. National Museum. 2a. Transverse section of the lower end of 2, showing 9 septa. 26. Drawing of the type specimen, by Mr. S. W. Ford. There are about 21 septa and the outer surface is removed. Collection 8. W. Ford. Fig. 3. EOCY8TITE8 ? f LONGIDACTYLU8 3. Enlargement of one of the plates occurring at Pioohe, Nevada, tion U. S. National Museum. Colleo- (968) 87 94 8 GEOLOaiCAI- ECRVEr BULLETIN NO. 30 FL V it » ■^1 .11 SPONGI02CA. iCHl.\CL:Ef^!v'ATA. 5 ■-: 1 i ii , '^i^' •r iM M'^ m !fl 'I'^j;: K^iK 1 1 fii'' M 'I t • » r ' . ■*?■ * i ■' . 1 X !■ ■». !1 If i t ■•'" 1 'ifil PLATE VI. 94 Fig. 1. EOCTSTITES t f LONOIDACTrLUS 1. Upper half of the body of a large specimen, pieserring several of the long, slender arms. The summit is crushed on the right side, causing the arms to bunch together. Natural size. Collection U. S. National Museum. la. Outline figure, natural size, of a specimen with the plates crushed in on each other. lb. Enlargement of the summit of a specimen from which the plates have been broken away, showing the structure of the arms and the casts of the short pinnulse. Three times natural size. Collection U. S. National Museum. lo. Enlargement of a group of plates from a large specimen, to show varia- tion in size, outline, surface markings, and the differences in the open- ings or pores on the margins of the plates. Fig. 2. Protosponoia 1 fbnbstrata f 90 2, 2a, 2h. Three forms of spiculaa. 2a is the form rarely met with. Colleo- tion U. S. National Museum. 846 (972) 1 U. B. CEOl^OClCAL DOKVEi BOLLEXII! in. 39 FL. VI 2a i r 1 SPONGlCZOA. ECH'NGDE = 'v'ATA. ! ( IM' I 1.* m. PLATE VII. P»ge. Fig. 1. litNOULELI^ C^LATA 95 1. Ventral valve, enlarged U> 2 diameters. (Drawing by 8. W. Ford.) Collection 8. W. Ford. la. Hide view of same, with a view of the beak, looking from behind. lb. Enlargement of a small dorsal (t) valve. Collection U. S. National Museum, lo. Dorsal valve, enlarged. Collection U. S. National Museum. Id. Surface of dorsal valve, greatly enlarged. * Fig. 2. LiNOULELLA Ella 97 2. Ventral valve, showing the area, deltidial opening, and oast of the ex- terior surface of the valve. Enlarged. See pi. viii. Collection U. S. National Museum. Fiff. 3. KUTORQINA PANNULA lO.'i 3. Ventral (?) valve, enlarged. The type specimen. Collection U. S. Na- tional Museum. 3a. Enlargement of a portion of the surface of 3. if ^i plate viii. Fig. 4. IPBIDEA BELLA 100 4. Copy of the original figure given by Mr. Billings. Ventral (f) valve. Collection Geological Survey, Canada. Fig. 5. ORTH181NA TRANSVERSA 121 5. Ventral valve, enlarged to 2 diameters. Collection U. S. National Mu- seum. 5a. Another specimen, showing the area. Collection IT. S. National Mu- seum. Fig. 6. Orthisina Orientalis 120 6. Ventral valve, natural size. (After Whitfield.) Collection American Museum Nu.tural History, New York City. Fig. 7. Orthisina FE8T1NATA 120 7. Ventral (?) valve and outline, natural size. Collection U. S. National Museum. 7a. Dorsal (?) valve, enlarged. Collection U. S. National Museum. 76. View of area of 7a. Collection U. S. National Museum. Fig. 8. Camarella (?) antiquata 122 8. Ventral yalve, enlarged. Collection U. S. National Museum. 260 (976) Z H. aEOLOOICAL bCRVEY liOLLETIN NO. 80 PL VU Irt '■'^; ; NTTriy i£i I'Bt''-'* ■f'.' ''H? fr%' Il ■ ;^; i ■'M^ ■ 1 K '' ■-' fl' • m *"' JM.^ 1 Wffy 3RACHI0P0DA. il 'I I 1 I -.J aj;;]' tl i 1 « -'1 * f^-W PLATE VIII. Fig. 1. ACROTRETA OKMMA 98 1,1a. Summit und side views of the dorsal valve, enlarged 3 diameters. Collection U. 8. National Museum. lb. Ycntra! valve, enlarged to '\ diameters. Collection U. S. National Mu- seum. Fig.2. KUTORGINA PANNOLA 105 2, 2a. Side and summit views of the dorsal valve, enlarged 3 diameters. Col- lection U. S. National Museum. 26. Ventral valve, enlarged to 3 diameters. Collection U. 8. National Mu • Houm. 2c. Enlargement of the svrface of 2b. Fig 3. Orthis (?) Highlandemsis 119 3. Dorsal valve, with most of the exterior shell worn away. Collection U. 8. National Museum. 3<(. Cast of the interior of the ventral valve. Collection U. S. National Museum. 3ft. Exterior of the ventral valve, with the side restored from another speci- men. Collection U. S. National Museum. Fig. 4. LiNGULELLA Ella 9T 4. View of the type specimen, enlarged to 2 diameters. Collection U. 8. National Museum. 4o. Cast of the interior of the dorsal valve, showing the position of the muscular scars. Collection U. 8. National Museum. 4ft. Cast of the interior of a very small dorsal valve, enlarged 6 diameters. Collection U. S. National Museum. 4t> Cast of the interior of a very small ventral valve, enlarged 6 diameters. Collection U. 8. National Museum. 4rf. '".ompressed ventral and dorsal valves from the shales of the Chisholm mine. Natural size. Collection LT. 8. National Museum. 4e. Enlargemeiit of the snrl'ace of a specimen from the shales at the Chia- hoh 1 mine. Collection U. 8. National Museum. Fig. 5. Lepkrditia Argknta 146 5. Crushed specimen of the left valve of the carapace. Natural size. Col- lection U. S. National Museum. Fig. 6. SCENELLA conula 127 6. tia. Side and summit views of the type specimen, enlarged to 4 diametera. Collection U. S. National Museum. «4 (980) Ptg^ diameters, tional Mu- itere. Col- /ional Mu- 105 \a '^b Collection . National tber speci- ion U. S. on of the Liameters. iameters. Chisholm the Chis- ze. Col- lameten. 119 97 146 127 ;!/( Aa -,achi!Jp:>ja. .CEA. ■i. J , < ' i: . PLATE IX. Pagoi Fig. 1. KUTORGINA CINGULATA 102 1, la, lb. Yentrul, lateral, aud dorsal views of a large shell tbat is mostly denuded of the outer surface. Collection U. S. National Museum. Ic. Lateral view of a sniall shell, to compare ' 'ith la, the height of the dorsal valve being much less than that of la. Collection U. S. National Museum. Id. Cast of the. interior of the dorsal valve, showing muscular scars. Col- lection U. S. National Museum. hu Dorsal valve, enlarged. Collection U. S. National Museum. If. Interior of dorsal valve. Collection U. S. National Museum, lij, Ih. Compressed shells from shales of Parker's quarry ; probubly ventral valves. Collection U. S. National Museum. Fig. 2. KUTORGINA .lAHUADOKlCA 104 2, 2a. Ventral valves, enlarged. Collection U. S. National Museum. 2b, Dorsal valve, tnilarged. Collection U. S. National Museum. Fig. 3. KUTORGINA PjtOSPECTKXaiS 106 3. Ventral ''alve, enlarged. Collection U. 8. National Mviseum. 13a. Dorsal valve, enlarged. Collection U. S. National Museum. * Fig. 4. ACROTHELK SUBSIDUA 108 4. Ventral valve from Pioche, Nevada, showing exterior surface, enlarged. Collection U. S. National Museum. 4a. Interior of dorsal valve, enlarged. Collection U. S. National Museum. 46. Ventral valve fiom Antelope Springs, Utah, with exterior surface re- moved, enlarged. Collection U. S. National Musonrii. 4o. Cast of interior of dorsal valve, enlarged. Coliection U. S, National Museum. a58 (984) BDLLETIN NO. 33 PL. IS m 1 11 i _■ . ■ M '■V' • ii:' ^^ \_y 20 2 i BRACH.ICPOCA. ■til !(■».. ' I'. 4!*:. :*,: ii I I A" PLATE Z. Figf. 1. ObOLBLLA CRA8SA 114 1. Tentral valve, abowing well-preserved exterior surface, enlarged to 3 diameters. (Drawing by 8. W. Ford.) Collection 8. W. Ford, la. Dorsal valve, with the outer surface exfoliated, enlarged. Collection U. 8. National Museum. lb. Dorsal valve, preserving outer surface, enlarged to 2 diameter . (Draw- ing by S. W. Foxd.) Collection 8. W. Ford, lo. Cast of interior of dorsal valve ; notation same as Id. Collection U. 8. National Museum. Id. Diagrammaticdrawingof the interior of dorsal valve. (Drawing by 8. W. Ford.) «, cardinal; c, central, and d, lateral muscular scars; x, area, le. Cast of interior of ventral valve ; notation same as 1/. Collection U. 8. National Museum. if. Diagrammatic drawing of the interior of ventral valve. (Drawing by 8. W. Ford.) a, cardinal; c, central, and d, lateral muscular scars; p, pedicle groove. Fig. 2. Obolella ormma 116 2. Exterior of a somewhat macerated specimen of the ventral valve, from Bic Harbor, enlarged. Collection U. S. National Museum. 2a. Ventral valve from Troy, New York, enlarged to 6 diameters. (Draw- ing by 8. W. Ford.) Collection 8. W. Ford. 2b. Interior of ventral valve from Bic Harbor, a, cardinal; d, lateral, and 0, central muscular scars ; p, pedicle groove. Collection U. 8. National Museum. 2o. Interiorof ventral valve from Troy, New York. The differences between 26 and 2o are largely owing to the condition of preservation of the shells. Notation same as 2b. Collection U. S. National Museum. 2d. Interior of dorsal valve from Bic Harbor. Better spr^cimens will be re- quired in order to make out the details of structure. Collection U. 8. National Museum. 2e. Exterior of dorsal valve from Troy, New York. Collection U. 8. Na- tional Museum. All figures of 2, enlarged. Fig. 3. Obolella CiRCK 118 3. Interior of dorsal valve. Compare with Ic, Id. Notation same as fignres lo. Id. Collection U. 8. National Museum. 3a. Interior of ventral valve (f ) ; 3 and 3a from L'Anse aa Leap. Collet* tion U. 8. National Museum. 868 (088) n. OEOLOaiCAL bdrvei 1 H -ih f: ".C -1 n :?« f ■ -I. '4 * ■t m e=!ach;o?o:)a I 1 i'i ■,i P 11 >? i I! i; I' I 't ii • 11 1 'I' III , • PLATE XI. Fig. 1. OBOLEI.LA CHHOMATICA 112 1. DoTBal valve from L'AnHe an Loup, enlarged. Collection U. S. National Miiaeuni. la. Ventral valve from L'Anse au Loup, enlarged. Collection U. S. Na- tional Museum. lb. Interior of dorsal valve, enlarged. Scars the same as in O. oraata. Collection U. 8. National Museum. Fig. 2. OBOLELLA NITIDA 118 2. Dorsal f valve, enlarged to 5 diameters. (Drawingby 8. W.Ford.) Col- lection S.W.Ford. Fig. 3. FORDILLA Tboyensis , 125 3. Kiglit valve, enlarged. Collection U. 8. National Museum. 3a. A shorter right valve than that of 3, enlarged. Collection U. S. Na- tional Museum. 36. Cast of the interior of the right valve, enlarged. Collection U. 8. Na- tional Museum. 3c. Left valve, enlarged. Collection U. 8. National Museum. Fig. 4. DiPLOGRAPTUS f SIMPLEX 92 4,4a. Two fronds, natural size, from the fine-grained argillites of Parker's quarry. Collection U. S. National Museum. Fig. 5. Climacograptus ? ? Emmonsi 93 5. The only specimen known to mo. Collection of Mr. E. Hurlbart. (992) •J. B. 0E0L03ICAL QCRVEY BOLLBTIN NO. SJ PL. X: I •I id' »■ .: 111 J ■} m^ ;i i r >f •>■ ^n ■'^^^^ f'il BRACHICFO:.A. HYDROZOA ^ ■-■! ■i fp m If m m L I ^^1 1 ■ 1 B' -! t ' r li 8 Hiii ' W ' ' aiii i . n ■I P. •' I PLATE Xn. Page. Fig 1. StENOTHKCA RUGOSA 128 1. Lateral view of a nicdiuiu-Hized specimen. Collection U. 8. National Mnseuui. la. Lateral view of a more elevated and coarsely aunulated specijueu than 1. Coll»>ctioii U. S. National MuHenni. 16, 1 tS' ' m ^MP ! !» ii" PLATE XIV. Pig. 1. Hyolithes impar '. 139 1, la. Lateral and ventral views of the type specimen. (Drawing by 8. W. Ford.) Collection 8. W. Ford. lb. Outline of cud of tnbe at point of septnm, and transverse section of same, enlarged. Collection U. 8. National Museniu. lo. Transverse section of 1. Id. Operculum from Troy, New York. Collection U. 8. National Museam. le. Cast of tube, showing constriction at the septum. Collection U. S. National Museum. Pig. 2. Hyolithellus micans 142 2. A fragment of the shell remaining in a natural mold, enlarged to show the annulations. Collection U. 8. National Museum. 2a. Enlargement of the terminal portion of » tube. Collection U. S. National Museum. 26. A crushed specimen in shule. Presented by S. W. Ford. Collection U. 8. National Museum. 2o. Exterior of operculum. Collection U. 8. National Museum. 2d. Cast of the interior of an operculum. Collection U. 8. National Mu- seum. 2e. Interior of nn operculum. Collection U. 8. National Museum. All specimens from Troy, New York, except 2b, which was found one mile below Schodack Landing. Fig. 3. Hyolithes communis 138 3, 3a. Dor.sal and side views of specimen from Bio Harbor. Natural size. Collection IT. 8. National Museum. 3b. Another specimen from Bic Harbor, Collection U. 8. National Museum. 3c. Operculum from Bic Harbor. Collection Geological Survey of Canada. 3d, 3e. Specimens from Troy, New York. Collection U. 8. National Mu- seum. 3/, 3g, Transverse sections to show irregularities of thickness of shell. Collection U. 8. National Museum. Fig.4. Hyolithes communis var. Emmonsi 187 4. Dorsal view of specimen showing evidence of three layers of shell and a septum. Collection U. 8. National Museum. 4a. Ventral view of a specimen, showing the constriction at the point of decollation of the apex. Collection U. 8. National Museam. S78 (1004) tJ. H. 0E0L031CAL BURVET BOLLETU! NO. 3) I'L. XIV lb o 'r \f. 2b \ i \d ac m\ w \h :!/ ©I ^.'' o W\ PTEROPODA. L-3 J 1 IMAGE EVALUATION TEST TARGET (MT^3) 1.0 I.I 1.25 l^|2^ 1112.5 |50 "^ 1.4 IIIIIM 1.6 V] n 0 m 77 y /A Photographic Sciences Corporation 33 WEST MAIN STREET ^ WEBSTER, NY. 14580 (716) 873-4S03 1 i" ■At V^-V".'-.,- I ■ii PLATE XV. Paca Fig. 1. Protooaris Marshi 148 1. Figure given in Bnlletin 10, U. 8. Geological Survey, plate x. Descrip- tion on page 50. Reproduced here in order to show the Bfiddle Cam- brian fauna, as known to me, in one series of plates. Collection U. 8. National Museom. (1008) C. B. OEOLOQICAL BCRVET EOLLETIN NO. 3) rL. S.7 m 148 >e8orip- le Cam- n U. 8. 'I '■i 'ni I FHYLL0PC3A. *''^> I 111* Iff I >i 'll \' 1 " PLATE XVI. Pig. 1. MiCRODISCtTS L0BATU8 l&C 1. Head, very muc]« enlarged. Collection U. S. National Mnaeum. la. Head, shovriug considerable variation ft'oni 1. Collection U. S. Nation- al Mnaenm. 1ft. Pygidiuro, very mnch enlarged. Collection U. S. National Mnsenni. Original Bpecimens from Troy, New York. Fig. 2. MiCRUDiscus Pabkbri V>7 2. 2a. Head and pygidium, enlarged. Collection U. S. National Museam. Fig. 3. MiCRODISCUS 8PECI08U8 154 3. 3a. Top and side views of a specimen, enlarged to 2 diameters. (Draw- ings by S. W. Ford.) Collection 8. W. Ford. 3ft'. Pygidium, similarly enlarged. (Drawing by 8. W. Ford.) Collection 8. W. Ford. 3o. Very perfect hrad from Troy, N. Y. Collection U. 8. National Museum. Fig. 4. MicRODiscuH Mkrki , ir>5 4. Type specimen, enlarged to abont 3 diameters. (Drawing by 8. W. Ford.) Collection 8. W. Ford. Fig. 5. Lbperditia Trotbnsis 14(> 5. Sketch of the type specimen, enlarged to 3 diameters. (Drawing by 8. W. Ford.) Collection 8. W. Ford. Fig. 6. AGNOSTUS INTKR8TB1CTU8 149 6. 6a. Top and side views of the type specimen. Collection U. 8. National Musenm. Pig. 7. AGNOSTU8 NOBILI8 150 7. Copy of Mr. Ford's original figure. Original specimen lost. 286 (1012) V. B. lEOLOJIOiI, 8tTR7Er BULLETIN NO. ») PL. X7: 15C 1. . Ntttion- isenni. IW useniu. 154 (Draw- lleotiou [useum. 155 ' S. W. 146 gbyS. 149 ational 150 \h C(i --'>>^ V It y CRUSTACEA. P 5 "I l<' 'll i'f nil I ml i I: In i if If t irll '• I, m i i' . Ut : I ''i 'ii. PLATE XVIL FigB. 1, 2, 4, 9. Olrnkllus Tiiompsoni 1. Heiul with an unusually broad liorder, fWxn Swanton, Vermont. Col- lection U. S. National MuMMiin. 2. Entire npccinien from line arKillacoous abales at Parker's quarry. Col- iKctinn U. 8. National MuHeuui. 4. ThIhou or pyK>i found in tbo Wiuooaki marble series, weut of Park er's quarry. Collection U. S. National Museum. 9. A very iwrfect bead, preserving tbe natural convexity, from the de- comiHised niiignesian limestone east of Swanton. As portions of tbe specimen were broken away otber specimens were used to aid the drauKbtsman in reiiresenting nn entire bead. Collection U. S. National Museum. FigB. 3, ,5, 6, 7, H, 10. Olenkllus asapiioid!:^ 3. Telson associated with fra^i'Heuts of this species at Troy, New York. Collection U. 8. National Museum. 5. Tbe youngest stage of dovelopuiont yet observed by tbe writer. Length, fonr-fifthN of one millimeter. Collection U. 8. National Museum. 6. A slightly larger specimen, l.TG'"'" in length. Collection U. S. National Museum. 7. Adult form. (After Ford.) Collection S. W. Ford. 8. Young form. (After Ford.) Collection 8. W. Ford. 10. Hypostoma associated with, and supposed to belong to, thia speoiM. Collection U. 8. National Museum. 290 (1016) Page. 167 168 H. aC0LO I III iOii »;iiJM < ■ -t II 1 l'!' Ei '■I'J^l' ;.!;*.:■• PLATE XXII. Pig. 1. Olenellus Thompsoni 167 1. A nearly eutire specimen from Parker's quarry. Natural size. Collec- tion U. S. National Museum. 310 (1036) i'' I 1 1* .'.I U' L". J. QEOLOiZCAL S'JR7L2 BDLLETIN l;0. 30 } L. SXi: Page. 167 Colleo- vMm |J|i;l PCICiLOPOCA. II i m m \t PLATE XXIII. P«ge. Pig. 1. Olbnellus Thompsoni 167 1. A specimeu allowing au uuusual prolongation of the third segment. Collection U. S. National Mnseuui. 314 (1040) -t U H OF.'LO-II'JAL !^"?,':E7 pollet::! v). si fl. :•:;%:: ::ecil:poc; PLATE XXIV. Fig.l. ME80NACI8 Vkrmontana 158 1. Copy of the original fl(;ure of tbb type specimen of the Hpecies. Collec- tion American Museum of Natural History, New Yorlt City. la. A very perfect specimen from the collection of Mr. E. Hurlhurt. The matrix is in the U. S. National Museum collection. lb. Enlargement of the posterior portion of In. The spine ])rojccting from the tifteenth segment is flattened down on the thorax more than is shown in the flgnre. Fig. 2. Paradoxidks rugulosus ,. 162 2. Pygidium and four posterior thoracic sc, lents, enlarged after Barrcnde (Syst. Sil. Bohfime, vol. i, pi. ix, fig. 31, . '"), which is introduced for comparison with fig. lb, 318 (1044) es. Colleo- Iburt. The ectiiig from iore tbau is r Bnrrunde roduced for 158 162 ■0 o F o ■D o > s o e > a a 's s M: i: i I llt«* bit! ! i m m >u> Fig. Fig. 2a Fig. Fig. Fig. Fig. 3 3, 3a 4. 4. 5. 5. 6. fi. 6a Fig. 7. Fig. Fig. PLATE XXV. Page- AnOMOCARK ? PA1{VUA[ '. 209 View of t,v]>e N[i(i!imt!ii, ('nlin>;cil Collection IJ. S. National Mnaeum. Olknotdks typicaus 183 View of tyi»o spccimon, iMil:ir;;(Ml to "i dijiniotors. Tim free cbeeks are displaced iu tlie original and arc n-storod from another sp»^cimen. Col- lection U. S. National Museum. A very small head, greatly enlarged. The ditt'ereiices^jif* compared with fig. 2, are in the form of the glabella and glabellar furrows. Collection U. S. National Museum. OlKNOIDES LEVIS 1S7 View of the type specimen. Collection U. S. National Mn.seum. . Lateral view- of 3. OLKNOIDKS ? FLAGinCAUDUS ItfS View of the ty])P specimen from Pioclie, \(!vada. Collection U. S. Na- tional Museum. Ptyciiopakia Housknsis 201 View of the type specimen IVoiu Auteloi»e Springs, Utah. Collection U. S. National MiiscMim. Olenoidks spinosus 184 View of tyi)e specimen froin the I'.nrclid districi, Nevada. Natural size. C(dlection U. S, National Museum. . Head of this or a closely allitd species fiom I'ioulK', Nevada. Preserved iu an arciiiiceous shale. Colicctinn l^ S. N.Uinnal Museum. Olenoides Nkvadkxpis 181 View of the type specimen of thci genus and species from Antelope Springs, Utah. Collection U. .S. National Mnsenm. Olexeli.us asapiioidks 108 Enlargemenli of a bit of the shell of th ^ * * t * • * . O. 8. OEOLOOICAL BDRVE? 16 BOLLETIN NO. 30 Tl.. y.XTW • la Ic Ul rWm I: 11 P- -^ 2a 3a 3& •CECIUOPODA. .1' iiU' ti; iifi PLATE XXIX. Pig. 1. OlBNOIDES QVABRICBPS 187 1. Original figure of Dikellocej)halui> quadriceps Hall & Whitfield, enlarged to 3 diameters. Collection U. S. National Museum. la. Side view of fig. 1. 16, Ic. Top and side views of iissocialedpygirtimn. CollectionU.S. National Musenm. Fig. 2. Olenoides Wahsatchensis 189 5j. View of the type speciniun of DikcUocephalns Wahsatchensis Hall & Whit- field. Collection U. S. National Museum. 2a. View of type specimen of DilieUovephatasf yothicus Hall & Whitfield. Collection U. S. Niitioual Museum. , Fig. 3. Okyctocephalus primus 210 3. Head with the free cheeks in outline; the latter are raised up and ap- pear broader than when attached to the central partis of the heatl. Col- lection U. S. National Museum. 3a. Pygidinm that is associated in the same piece of rock with the head wherever the latter is found, enlarged to 4 diameters. Collection U. S. National Museum. Fig. 4. Ptychoparia quadhans 199 4. Central portions of the head with the free cheeks restorcvi in outline. This figure varies from that given in vol. iv, Geol. Expl. Fortieth Par., pi. ii, fig. 11. It is drawn from a specimen marked as the type of the ' species. 4a. Associated pygidinm. 46. Associated free cheek- 338 (1064) O. 3. OE0LO:3;CAL SDRVEI BnLLETIN NO. 3:) PL SSIX la 16 Ic 3a 4rt 1-^ '^M^ PCECILCPOCA. III.' I- PLATE XXX. Pagft Fig, 1. BaTHYURISCUS PRODDCTU8 217 1, la. Narrow and broad forms of the head. Wasatch Mountains. lb. Free cheek associated with la. Ic. Large head from the Highland Kauge. Id. Pygidinm associated with Ic. ; le. Type of Ogi/gia parabola Hall & Whitfield. If, Iflf, Ifc. Pygidia showing variation in form. li. Restoration from specimens obtained in the Oqnirrh Range. Originals in collection U. S. National Mnsenm. Fig. 2. Bathyukiscus Howelli 21C 2. Type specimen, enlarged to 2 diameters. Collection TJ. S. National Mn- senm. '2a. Central portions of head, enlarged tn 'i diameters. Collection U. S. Na- ' tional Museum. 342 (1068) ffl 0. B. OEOLOOICAL STRTET BOLLEn.V NO, ,iD PL. aSS Iff Ir 217 /«» 1« a^inals IMu- !. Na- 21C 1,7 2n l/t PCEGiLOPODA. Hn ' Species of, in Cambrian, 61. Hiiydeni, 215, 216. 1 1laydoni, 215. Howelli, 34, 48, 50, 215, 216. Huwelli, Explanation of figures of, on plate XXX, 842. prodnoto, 84, 30, 40, 48, 57, 95, 2] 5, 216, 217. (1084) BatbyuriHCUs— Continued. producta. Explanation of fignrvs of, on plate zxx, 842. Bathyuru8,213,210,321. doubtfully identified in Cambrian, 63. 1 in Upper Cambrian, not in Lower or Middle Cambrian, 62. sp. t, 19. ) Species of, in Cambrian, 01 . extans, 20, 215, 219. parvulus, 213, 214. senectus, 213. Bellerophon, in Upper Cambrian, not In Middle or Lower Cambrian, 63. Species of, in Cambrian, 60. antiquatus, 35. Bennett's Spring, Xev., Section near, 33. Beyrichona, limited to Lower Cambrian, 62. Species of, in Cambrian, 60. Bio Harbor, Conglomerate limestones of, 24, List of species of, 26. Big Cottonwood Cafion, Great Cambrian section of, 88. Big Cottonwood section, 38, 41. Billings, E., 40, 64, 114. As to certain species recognized and de- scribed by, 2». Middle Caml>rian fauna Classified as Lower Potsdam by, 49. BUlingsia, in Upper Cambrian, not In Middle or Lower Cambrian, 62. Species of, in Cambrian, 60. Saratogensis, 21. Bonne Bay, Georgia fauna of, 29. section, by Sir William Logdn, 20. Bornemann, J. G., 51, 80. papers published by, 81. Brachiopoda, 62, 96. Distribution of species of, in the Middle Cam- brian, 46. Genera and species of, 48. Genera and species of, in Cambrian fauna, 62. Genera of, in Cambrian, 60. Braintree fauna, 44, 40. C. Calathium, 70. Calciferons fauna, 63. formation, 22. fossils, 24. horizon, 21. Calymene Beckii, 203. Camarella, 48, 122. common to Middle and Upper Cambrian, 02. Species of, in Cambrian, 60. sp. » , 26. tsp. »,46. antiqnata, 19, 122. fantiqnata, 46. (f) antiquata. Explanation of figures of, on plate vii, 260. varians, 122. "Volborthi, 122. Camarotheca, 131. Cambrian, Conditions ueveloping Middle fanna of, peoaliar to Kortb America, 57. fl)Oirf« of, on plate mbrian, 6». D Lower oi- Middle iaii, Dot In Middle 1 near, 3S. Cambrian, 62. stonef) of, 24. Carobriaii seotioD cogniznd and de- asaifled as Lower not in Middle or INDEX. 359 In, 29. the Middle Cam- nbrian fauna, 62. • Cambrian, 82. figures of, on Middle faana »,57. Cambrinn — Continned. Doiibtl'ul pennra of, (Ki. Ulntrict ofCuniilurande in Sardinia, 80. I'auim, SpecinH of, tH, fiiiinuH, BH (lorit'lBtfd !)> P'- •»'. Whitfield, 1.1. I'niinatt of North AimTica, l>. fHUiiiiH of North America, Siiiiimnrv of, 30. forniiitioii, Totnl thtclcui'HS ot', 11. r)riii>raoftheOI('iiidiii of Aini^ricaii Middle, niS. Lower and Upper. Oeuernrouiiiiou to the, tl'i, Ixiwer, Gfiiorii aud BpccicH < '' III. Lower, Genera enmmon to il ti'2. Lower, (Joiiera limited to thr, (I'i. Lower, Uuiiura of the Upper not ocourring ill tlie, iVi. Lower, Middle, and Upper, Genera coiiimon to the, (I'i. Lower, of Sedgwick, (18. Lower, or I'nrndoxideg fimna, U. Lower, Period of oronion of, i'.t. Lower, St. .lohn HuriuH, 14. Lower, SvMteniatic poHilioii of, . Middle, Genera and Npecloaof the, 01. Middle, Genera common to the Lower and, 02. Middle, Genera limited to the, 62. Middle, Geiu'ia of the Upper not occurring ill the, 02. Middle, or Georgia horizon. Review of the Htiata and fauna.s referred to the, 12. Middle, Period of erosion ol the, 43. Middle, Species id' Kutorgiua in the, 101. Middle, Systematic position of the, OX Miecie» of, in Cambrian, 59. (0 Kmnionsi, !.'>. 51. ■>! Emmonsi, 40. )>3. ?f Emmonsi, Explanation of hgure of, on plate xi, 26». CliniactichnitcH sp. !, 21. Species of In Cumbrian, 00. in Upper Caralirian, not in Lower or Middle Camlirian, 02. Coleulus, 131. Coleopriim, 131. Conglomerate limestones of Bio Harbor, St. Simon, St. Lawrence River, Island of Or- leans, &c.,24. Conglomerates at Point Levis, of Calciferona age, 23. Conocephalidae, 56. Conocephalitos, 21B. Adamsi, 195, 108. arenosus, 195, 196. coronatus, 195. miser, 199. snbcoronatns, 188, 205. Sulzeri, 195. Teuoer, 197. trilineatns, 203. ( Atops) trilineatns, 203. Vulcanus, 198. Conocoryphe, 203. Uniit<>d to Lower Cambrian, 62. Species of, in Cambrian, 61. (Conocephalitos) Kingi, 193. (Ptychoparia) Kingi, 193. Conophrys, 153, 157. Connlaria, 131, 223. fecunda, 223. Conularidffi, 131. Correlation of sections, 40. Corynexochns, 187. spinulosus, 214. So) i 360 INDEX. C'nNcinocyntliiiH, RO. • 'rnnin (Kiitoritiiiu) Lubrndorlcu, id. Cic]iiu('ijliului), 30, Ad, '20tt. coiimuiii lu Middle iind Upper Cumbriun, 02. SpucicH of, in Cumbrian, 61. AiiMUHtit, Kxpliiuattuii of flitiireii of, on plato xxviii, iiiU. AuKiiNtn, n. tp., .'lit, 4H, 208i IowouhIh, 208. Ltltana, !l.\ 48, 207. I^llluuu, Kxplanatiou of flgureR of, on plate xxviil, 334. I (IjOkuduUuh) quad raOH, 100. Crinoidea. UiHti'lbutlon of Hpocleii of, 4tt. Qonera and Hpecles of, 48. Genera and Hpeoieg of, in Cambrian, 62. Oenora of, in Canibrinu, SU. Cructtucea, A4, I4H. ViHtrlbution of apRcies of. In the Middle Cum- brian, 47. Genera and apecios of, 48. Genera and apecioa of, In Cambrian, 02. Genera of, in Cambrian, 60. Cnizinua, 72. common to Middle and Upper Cambrian, 62. Spcciea of, in Cumbrian, 59. ap. (.'),34,30,4.'). CryptozoA proliferum, 21, 225. CtonocephaluH, limited to Lower Cambrian, 02. Speciea of in Cambrian, 61. Cypbaspia Hunneistor, 184. 1). Dulmuuia, 180. Dnna, .T. D., conHiilersEuiraona'aTaconicaa Lower Silurian, 70. Dawaon, George M., 40. Dawson, J. W., 70. < UenilrograptUH, !S0. eomnion to Lower and Upper Cambrian, 62. SpecioH of, in Cambrian, 50. Dicelloceplialus, 30, 181, 185. in Upper, but not in Middle or Lower, Cam- lirian, 02. S)ieciea of, in Cambrian, 01. ap. ?, 3.'5. Minneaotensis, type of, 35. nngustifrons, 33. bilobus, 33. Hartli, 21, 225. Lodenaia, 21. Marconi, 180. Marica, 33. ?na8utu8, 32,33. Osceola, 33. ropincnsia, 21, 35. ? quadriceps, 187. Uicbmondunais, 32. s]>ecioaua, 21, 225. Uicellomus, 109. Dikellocephalus nothioua, 188, IflO, 222. ( Sotliicua, 189. [ magniflruB, 185. quadricepa, 187, 222. Wabsatcbensls, ISO. 190. ?gorax, 185, UiploKraptua, 03. SpecioH of, in Cambrian, SO, ae«:alinua, 02, 03. (t) simplex, 15, 40, 51, 03, 03. (?) simplex. Explanation of fl){nre of, on plate xl, 20«. Dlplotbeca, 131. limited to Lower Cambrian, 62. Rpooiea of, in Cambrlau, 60. Dlscina, doubtfully identified In the Cambrian, 63. In Upper, but not in Middle or Lower, Cam- brian, 62. Species of, in Cambdan, 00. Acadioa, 128. Diaolnella, 141, 142. Dorypyge, 221. Ricfathofeni, 222. Dwi^lit, W. B., deacrlbca belt of Ilmeatone near FouKbkecpaio, 23. B. Echinodennata, M, 94. Kchinognathua Clevelandl, S4. Kllipsocepbalus, 162. Elllptocopbula, 102. aaapboides, 108. EUiptocepbaluH, 102. usapbotdea, 108. £ly Mountains, Olenoldos fanna in the, 86. Emmons, E.,72,04. concct in claaaifying Upper Taconio as pre- Potadam, 05. Extracta from works of, 60, 67, 68, 69, 70. Endo);ranima, 200. Eocoryne, limited to Lower Cambrian, 62. Species of, in Cambrian, 59. Eocyatites, 04. ? common to Lower, Middle, and Upper Cam: briun, 02. Genua of, in Cumbrian, 50. 1 ap. 1, 40. ?? longidactylua, 34, .35, 40, i>l, »»<,95. ?? longidaotylns. Explanation of tigures of, on plate V, 242 ; on plate vi, 24». Eopterin, liichardsoni, 53. ? ornata, 53. typica, 53. Eospongia, 79. Eozoiin, 79. Ethmophyllum, 51, 73, 75, 80, 82. Explanation of figure of, on plate Iv, 288, limited to Middle Cambrian, 02. Species of, in Cambriun, 59. Billingsi, 80. gracile,30,81,83,g4, 85. Mlnganensla, 51, 75, 77. profundum, 20, 38, 45, 'M, 73, 74, 75, 77, 84. profundura. Explanation of figures of, on plate i, 22« ; on plate ii. 230 ; on plate iv, 238. rarum, 27. 45, 87. rarum. Explanation of figures of, on plate v, 242. Ronsselaericnra, 27, 76, 85, 80. Renaselaericum, Explanation of flgares of, on plato V. 242. Whitneyi, 30, 38, 45, 75, 76, 81, 83, 84, W, (1086) :i){nre of, on plate the Cambrian, S3. 5 or Lower, Cam f limeHtone near in the, SB, ' Xaconio aa pre- r, 68, 60, 70. irian, 82. md Upper Cam: ,95. if figures of, on Lto iv, '288. 5, 77, 84. ree of, on pUte late iv, 238. of, on plate v. f flgarea of, on 84,86, INDEX. 361 Etbinopliyllum — Couttiiiie4. F. Fiiiino, Urainlrri-, 411. DeNoriptiou of the .Middln Cainbriaii, 72. OcutM'u of Olt-nido) of Aninric.tn Middle Cam- brian, nnlata vai . pusilla, 102. Labradorlca, 15, 18, 19, 20, 29, 46, 101, 102, 104, 106. Labriulonca, Explanation of figure? of, on plate ix, 258. (like K. cingulata), 38. minutissima, 32, 33. pannnla, 34. 35, 39, 46, 99, 101, 102, 105, 106, 216. pannula. Explanation of figures of, on plate vil, 269 ; on plate vili, 254. Frospetlonsis, 32, 46, 101, 104, 100. Prospectensis, Explanation of figures of, on plate ix, 258. sculptilis, 101, 102, 106. Whitfleldi, 32, 101, 102 L. Lamellibranchiata, S3, 123. Distribution of species of, in Middle Cam- brian, 46. Genera and species of, 48. Genera and species of, in Cambrian, 82. One genus of, in Cambrian, 60. L'Anse nu Loup. 32, 38, 74. Hcction 2tt. Species from, V9 Leutile, 17, 18. (1088) ..J" 1, 132, 186. jares of, on plate Middle or Lower, , 62. 126. a of, on plate vli, ge, 64. and Upper Cam- 29, 38, 46, 52, 101, giires of, on plate 46, 101, 10?, 104, figures of, on 102, 105, 106, 216. nrea of, on plate 106. of figures of, on in Middle Cam- ibrian, 82. INDEX. 363 Leperditia, 14(1. common to Middle and Upper Cauibiiun, 6J. Argen'-sia, 47, 54. Argi-ita, Explanation of ttgiiro of, on plate viii 234:. 1 Ar«inta, n. sp. 140. Solvensis, 146. Troyon8i8,2;,47,54, 14«. Troyensis, Enlarged ttjuro of typo specimen of, 'ambrirtu, 6J. Species of, in f'ainbriiiii, CO. Leptien:'. Species of in Caml)rian, 60. ? in Upper, but not in Middle or Lower, Cam- brian, 02. Leptoniitus, n. pren., 89. Iimite. Zittoli, Kxplanation oi' tigures of, on plate ii, 230. Limestone near Poiigbkeepsio, N. Y., '£t. Linguln, 97, 104. in Upp'.^r, but not in Middle or Lower, Caui- briaii,62. np. ?, 19. Spegna, 22. Marcon, Jules, 72. I Lentile of, 17. Strata referred to Potnlam by, 18. I Matthevia, 131. 22iJ. variabilis, 21, 223, 224. vaiiabilis. Explanation of Uguresiif on plato xxxii, 350; on plate xxxiii, 354. M:-..tliovidie, 131. Matthew, G-. F., ,53. Met;k, F. B., 3, 176, 177, 178, 179, 1?0, 1^7, 181», 208,210,217. Gilbertl, Explanation of figures of, on plate xviii, 21(4 ; on plate xix, 29S ; on plate xx, 302 ; ou plato xxi, 30tl. Gilbert!, Observations on, 173. Gilberti (=0. HowcUi), 164. Howelli, 107, 164, 170, 171, 173. Iddingsi, 32, 34, 35, 30, 47, 107, 170, 174, 178, 210. Iddingsi, Explanation of figure of, on plate xix, 21tS. Tbompsoni, 1.5, 18, 19, 26, 29, 32, 3«, 47, 89. 93, 95, 104, lOJ, 111), 121, 141, 158 159, ISl, 10;i, 165, 166, 107, 168, 169, 171, 173, 17,5, 176, 178, 179. Tbompsoni, Explanation of figures of, on plate xvii, 290 J on plate x.\ii, 310; on plate xxiii, 314. typicalis, 50, 95. Vermontana, 158. 159, 176. (=MeHonaci8) Vermontana, 167. Ollenellus borizon— Georgia or Middle Cambrian, 44. east of Swautoii, 19. Fauna of, east of Swanton, 19. Relation of, to Potsdam horizon, 33. Separation of the, 33. Olenida;, Genera of, iu Middle Cambrian, 55. Olenoides, 30, 55, ISO. fauna in Ely Mountains, 35. Genus itroposed, 183. limited to Middle Cambrian, 62. Species of, in Cambrian, 01. expansu.s, 222, flagricaudua, 47, 181 , 222. ? flagricaudus, 1S5. tflagricaudus. Explanation of figure of, oh piate xxv, 322. levis, 20,35,47, 1>T, 222. levis. Explanation of figures of, on plato xxv, 322. Marconi, 1,5, 26, 47, 56, 95, ISO, IbU, 190, 222. Marcoui, Explanation of figures of, on piato xxvi, 320. Nevadensis, 40,47, 1S1,22&. Novadensis, Explat)''tioii of figure of, on plate x.NV, 322. q":uii i-^eps, 32, 47, 1J»7, 188, 189, 100, 20.5, 222. quad,,ticps, Exidanatioc of figuie.Hof, im plate xxix, 33S. spinosus. 32,47, 181, 1S4, 1H7, 222. spiuosuH, Explanation of figures of, on plate xxv, 322. typicalis, 34, 47, 180, 181, 1S3, 187, 210, 221, 222. typicalis, n. sp.. Explanation of figures of. on platt^ xxv, 322. Wahs.itcliensis, 47, 188, ISO, 200, 200, 222. Walisatobcusis, E.vplauatiou of figures of, on plato xxix, 33S, Olenus, 102,104,105. ? ia Upper, but not in Middle or Lower, Cam- brian, 02. Spoi-icH of in Cambrian, 61, a.saphoides, 108. (1()«>0) INDEX. 36^ I, 55, 84, 95, 105, 1,5,106,169,170, ro, iFO, le", is'.t, 38 of. Oil plate ; oD plato XX, >, 174, 178, 210. •e of, on plate 3S,47, 89, 93,95, 01,16,), 165,166, 178, 179. ires of, on plate o!i plato xxiii. 7. ildle Cambrian, 1, 33. ibrian, 65. ii^urfi of, OH on plato XXV, , 190, 2'J2. .s of, on plate ■a of, on plate 21tj 221 222. figures of, on 206, 222. llHUVcH of on I.owiT, f'ani- Olonus — Coiitiniiid. (OIpucUus) Gilbertl, 170. (Olent'llua) Howelli, 171. NevadensiH, 18,1. Tlioiupsoni, 167. Vcrmsntana, 158. Opbilta, in Upper, but not in Middle or Lowor, Cambrian. 62. Species of, in Cambrian, CO. conipacta, 22. Orjnirrh Range, Cambrian secition of, 'M, Orbicula csrlata, 95. Orbiciila ? cra.smi, 114. Manio as Obololla crasaa. 111. Ordovioian, 44. Ortbia, 48, lUt. • genus 1 jiutnoft to Lower, Middle, and TTpper Cambrian, 62. n. sp., 26. ?Hp.,29. a^. I 27. SpVicies of, in f'ainlirian, 60. Eurekcnaia, 3L'. Higblaud ns'.s 35,40 ? IligblaiidenHi.s. n, aii., 11!), ? Higblaudcnuis, Explauation of ligurea on plate viii, 2o4. Orientalia, 15. Ch' - -(, 48, rid. » jnii' i.n to Middli' and Tppcr Cambrian, 02. sr {-., 15, ]?, 20, 4ti, 99. sp. iindt., i'l'i. Spccii's of, in Cambrian. 60, featinata, 1.5, 18, 19. 4ii, .52, 120. festiuata, K.^pUmation of iignrea of, on plali^ vii, 2.">0. Orienfalia, 19, 40, 49, I'iO. lOrientalia, 119. Orient ali.'^, Kxplanatiou of ligiuv of on pliite vii, 'ioO. I'opina, 49, 119, 120. tranavoraii, 15. transveraa, Kxplanation of figures of, on plati- vii, no. .'transversa, 40, 1'21, Ortbocciatitea, lliR. Orycloccpbalus. od. limited to Middle Cambrian, 02, Sjiecies of in Can)brian, 61. piimuH, AH, 'ilO. prinitix, Kx]ilaiiation of Mgurea ol'. on plate xxix, :t'>S. I'agiira, 191. I'aliniiia'iat liange, Silurian of :10. I'alieaeniea, in I'piier, Init not in Middle or Lower, C:ii]ibrian, 02. SjHM-iva of ill Cambrian. 00, typiea, 21, rali'clionla, inT'p])ei, but not i;, Mid'!. i.' or Lower, Cambrian, 62. Speeiea of in (,'anilii iaii, 59. Pabenignia, Kll. proposed in place of 'I'etriidiuiii, 223. >Vrangeli, 224, PaliEnignia — Con! iuued. Wrangeli, Explanation of flguros of, on plate xxxiii, :t5t. Paleo])bj-cus, 72. • eonimon to Middle and ITppor Cambrian, 62. Spoci(^s of in Cambrian, 59. <-ongregatua, 15, 4,j, 72. iucipiens, 15, 27, 29, 45, 72. Paialiolina, 181!, Nevadensia, 18:(. Paradoxii'ea, 44, 160. 102, 164, 165 166, 181, 182, 183. fauna, i ; , 49, 5S. fauna of .St. John, Braintreo, and Newfound- land, Stratigraphic relations of, 40. limiti d to Lower Cambrian, 62. lieiationa of, to Mesonacia and Olenellna, 1«5. Speeies of in Cambrian, 01. aaapboides. 168. Barberi, 29. expectaua, 162. Forcliammeri, 104. Kjenilli, 101, 162, 166, 178. lijerulti, Explanation of figure of, on plate XX, ao'i, L.velli, 162. niaerocephaluB, 167, 188. JXevadenais, 180, 181. Oelandicus, 162. (luadriajiinoauH, 191. ?quadrispinos«is. 191. (Pagura) iiuadiispinosus, 191. rugulosua, 161, 162. 166, 183. ruouloaus. Explanation of figure of, on plate xxiv, 31S, K.ieberi, 161. spinosua, 161. Tliofnp.soni, 167, 191. Verniontana, 1.58, 191. I'.irailoxidea liorizon, Oeuera of American, 50. TarUer'a farm, 17. I'arUcr's nuarrv, Fossils in sbales of, 15. G<'orgia section at, 13-17, Peltocaria. 148. Peltura, 187. (t)lenus) liolopyga, 191. Pempliigaspia, in Upper, but not in Middle or Lower, Cambrian, 62. Speeies of in Cambrian, 61. b\illata, r>:>, 153, 154. Phacops, 191. Pbillipsburg formation, 22. i'hragmotbeca, 1,'il. Pioelie. Xev., Sjieeies fnun, 35. Tliickneaa of quartzito at, 36. riautn', 48, 50. I'lat.veeras, i;;0. common to Middle and irpjier Cambrian, 62. Sjipcies of, in Cambrian. 60. Koyti, 21. n\iuntia,siniiim, 21, 131,225. primaviini. 20, 27, 46, .53, ISO, 131. primavuni, Explanation of ligures of, on j)late xii, '270, Plenrotomaria, doubi fully idciitillcd in Cambriuii, 03, (1001) 366 INDEX. W \ * ,? *f Pleurotouiai'la — ('i)iitiiiuocl. ?, in XTppnr, Imt not in MidiUo or Lower Cam- brinii, G2. 'Species of, in Cambrian, OU. Hp. iindt. (i). ■'!•">■ I'cpcilopoda, M, I ll>. Di.strilmtion of species f)f, in Middle Cam- brian, 47. IS. (icncra and sjiceii^s of, 48. (ienera and iii)in)]iared witli Wiscousiu Potsdam ■(itndHtone I'auna, 21. I'ppcr, S|i( ciis in, I!,'). I'oi.ud.ini format i(pn, nrar tiie Adlronda>f, to Georgia or Oleuellns, U.'t l'])I'er liMiit of tlie, 14. I'otrtdam limi'stone. 4'). !'ot,sdaiii Lower, Funua of fleorpia sIialoH referred to the. 20. iiivriiHjiiven by liilliii);stoiridd!e''ainbrian, 4!*. I'otsfl.im or Tlici'lloceplKiliis ITjiper Oambi'fiin, 44, IV)tsdi'.m sandsKme, 21), 23. I'riinonlial Zone of Life perhaps equivalent t> the, 14. I'ofsdaiM series, Strati;;iaphir relations to Georiii i series, 20. Pre-Candirian. 14. Callinile beds piiibably belons to the, 'M. fitrnta of the fliaiid Ciifion, 41. Primitia!, Species of in Cambrian, tiO. Primordial fa>:n.i of liarrande, ii.'i. or (-"anibrian I'eiio.l, 12. \'i. Pr'^tns decoviis, 170. vemistna. 176. Prospeet Mountain limestone. 32. Prii.-ipeel Mouutiiiii <]iuirtziti'. IHI, ProapevI M,)unt.iii! shale, ;|(i, Protiehnites, in Upper, but not in Middle or Lower. CamViri/.n, 02. ,Spe\, ttO. / fnnestrata ?. Explanation of fignrcs of, on plate vi, 240. Protypns, .5(1, limited to Middle Cambrian, 02. n. <;en.. 'ill. Species (if, in (Cambrian, 01. exp,insnH, ,'t2. llitcbcocki, l."i, 48, 211, 21.'!. Ilitcheoeki, Bxplauaticm of tiguie ot', on plat« XX xi, ;i4(i. parviilns, 213, 214. 8en»etU8, 1.5, 19, 20, 2!), .'(2, 40', 4S, fy"., 213. ^enectus, Explanation of IttMiri^s of. on plato xxxi. 34t». seuectus var. parvnlns, 1."). 28, 29, 48, Plychoparia, 19, 35, 48, llt3. and subgenera, common to Lower and Middle Cambrian, (i2. and subgenera. Species of, in Cambrian, 61. common to Lower, Middle, and Tipper Cam- brian, 62. sp ? 32, 3.5, 4.8. 202. sp. nmU.,26. Adaiu'i, 1,5, 17, 18, 1ft, 20, 26, 47, 4ft. 141, 105. 199, 200. Adntnsi. Explanation of ftgures ol. on plato XX ri, 320. iilUuis, 33. bella, 32. Billingsi. 198. brevicep 33. calcifera. 21. (i=('ouoiephft!ite8), 193. (— (./'onoeepbalns), 193. dissimiliH, .<2. (Enlotiin ?) dissimilis, 36. Emmrichi, ?02. griinulosji, 3.'t. Uaguei, 32, 33. Ilousensis, 40, 47, 201. HouHen;*is, Explanntinn of fignres of, on]dat4< XXV :{22. (Crepi'i'pliii'.uH) Iowens\s, 200, 207. Kiu«i, 40. 47. 10ft, 103, '200. 201 Kin:.:!. KxTilanution oi ligures of. on plate xxvii, 330. Itevieeps, i^i. ' St S( .Sn (100-') id Upper Cam- ngurc» of, on iincof, on plat« 48, O'l, 213. ivus o)'. oil V'"'** 5, 2'J, 48, 4tt, Vi6. in Middle Cam- mbriuii, 02, Middle or Lower, Lower and Middle 1 Canil)riai>, 61. aud Tipper Cam- » 47, 4!), 141, 10,5. 'rtres ot, ou plato flanreHof, onplato iOfi, 207, ill. unw ol', <•" pli'*f INDEX. U1 t^.yoboparia— Continued. latic»jpp, 32. LincamHoni. ^12. JLiuaarsuwiii, 205. (Lonohocopbalvii*) oalcifeni, 226. miuoi, 34, 35. mlnnte, 21. mi^fcr, 29, 47, 1«». mioer, Esp^.aration of fleuroi ol', ou plate xxvii. 880. occidfUtJiliig, ;i2. Oweni, 32, 33. Owcnl (ot'Ha'.l), 21. perniiauta, 32. PiocUensia, 34, 47, 5tt, 95, 201, 2i0. Piochousis, Explanfltion of flr,Dre8 of, on plate xxvl, 32tf ; on plate xsviji, 334. ProsipectunBlH, 32, 20ii. I Prospectenais, 47, 'iO'i, 1 Proapectensis, Explanation of figures of, oo plat« xxtrij, ;i;{0. quadrans, 39, 47, 11)!». quadraus, Kxplanation nf fijriireB of, oj plate xsix, 338. (Agraiilos) Saiatogennifl, 21. (Agianlos) atrenuus, 2(5, 47. seueotus, 214. Blmilis, 32. aininlata, 33. siibcoroniita, 47, ^0.5, 206. sultforonata, Eiplaiiationof ftsareof, on plate xxviii, 3.?4. Teucer, 18, 26, 197, 199. Tencer, Exp'iauatiou ol figure of, on plate ixvi, :in. tviliucata, 20, 27, 48, 20.3. ti'ilini>ata, Kxplanation of flgur^^a of, ou ylAto xsvii, 330. uDisulcata, 32, .33. Vnlcanuif, ir,, 26, 48, 1 Vulimnii8, Ksplanatiou o.' B};ur'!.s of, on plate xxT! 326. V/i8Coiii*enais, 21. PughiDcnlas, 131. R. lienaselaer County, Sections ip,de8cribiM! by Win- luona, 70. libyuchonoliidtB. 53. Khyaospougia. 70 St, .folni fa'inn, •)!». St, Joliu G'oup. Gviiptolitos in, 51. Hyo'iitlies from, liavc uintin< t •^t i>ta, I3f. St. Lav.rciii'o Valley, 24. St. Simon, Coujtlorji'rate liniesiones of, 24. List of species from. 2G. Snlteri'll". 131, ]■(«, 137. US. limiifd to Middle Cauibiian, 62. Mil., •jtl, .Spi'cits of, in Catubriau. 60. j iilitnsii, 134, 144. l>nlr(i«lla, 26, 20,47 134,111, )>^,. fiiiU'liilla. Kxi'ldniitiidi of tijnio.H of, or plate xii. 270: on plafu xiii, 274, pnlcliella {!). I'l, 18. IB. rugosa, 2», 47. 144, 14.'. iW'Jo) SalfceroUa — Con t.niiod . rPKOs*, KxpSanal'ion of fsore of, on plate xiii, 274. Salterelhda), J 31. SftrMogft Potsdain fi»nn«. compared with the Wis- conaiu PotRdani 8a.ndatone fauna, 31. Saiwroga Spi ingu. Section west of, 22. Gaidinia, 57. Caiubriun diHtrtci, of Canalgrande iu, 80. SceiteUa, 125. limited lu Middle Cambrian. 62. Species of, 11 Cambrian, fiO. conula, 32, 4C, 136 conula. Explanation of figures of, or. pbite viii, 251. ? conula, 127, reticuLita, 20, 46, 49, 125, 126, 127. ruiiculattt. Explanation of flguri's r,f, on plate xii. 2T0. retasa, 20, 27. 46, 12-5, J2«. retus-i, E:cplunation of Hruii'm uf, ou plato xii, 270. variana, 18 12.'). ? varans, 4(;, 127. 1 variana. Explanation of ti^nros of, on plate xii, '>7ft. Schi^iimboii, yennfi, 52, 107, SchjdacTi Landing, Stction aouth of, by S. W. Eor.l, 2V, 2S. Spocies Iroai, 27 Scolitlirs, in Upp'n- Imt not in Middle or Lower, C.iinibi''iin, 82. Spocios of, in Cambrian, .W. Pcyphia, 79. Second far.na. 63. Sei-'et Caflon shale, 30. Section, at '/Ause aii fxiuj . 21'/. at Trois Pistoles, de<', l>y S, W. Fold, 27. Big Cottonwood CaBon, 41. Camt>rian, Euroka mining district. Central Ncva«ia, 30, CiimbriiD, Wbile's Peak, Xevada,41. east of HighgKto SpringH. Vermont, 18. oast of Swanlon. Vennont, 18. Eureka t^anihriw). H.'i, Georgia. 19, 1,4, 43 Oeorgiii, it Parker » (|narry Ac, 15-17. Georgia, rignrf of, IW, Grajjd Oafion, fo.-isils ol, 4t. Great Cambrian of ( ot'onwood CaOou, «8. Higher strata ot Ui^hiand Range. 36. Highgate, 19, 24. Highuiate, ot Hitcheoek. 20. Higiiland Raugu. m>vcA of Eureka, 33. illu«tratiiig the Tueouic HvAteni S. W. Ford, 27. U. Upper Camlinan, 19, 99. Utica sbalo, 24, 43. Vaginelirt, 131. Yermont, Xortbm t, Potsdam formation not ob- served in. as it exists in New York, 23. section, 28. sections, by C. II. Hitchcock, 20. Western, sections, 13. Von Jlieruig, 138. Tacouie, On tlio use of the mime, C5. of Eiiiinoiis cdiisiileieii by Dana as Lower Si- Inriait, 7(1. Wasatch section, 3S. grai)toliUs. 02. I "correlated, 44. (1094) w. 1,70. >n illustrating the, n of, by Emmona, Bumona to divide Emmona as pre- I in placo of, 223. lura at, 29. rray, 49. lubiian, 72. >t in Middle or Middle or Lower, om, 2rt. orra.ition not oli- ew Yorls, 23. i, 20. Ix\i)EX. 369 Wbitllcld, n. p., Cambri; 13. Ill I'iltlll -.A ((UTI)I.lIcd l,v, Whitney, J. D., 36. Wlnchell, N. H., 29. Wiuooftki niarlde, 23, 145. Wisconsin Potsdam sandstone fauna compared with Saratoga Potsdam fauna, 21. Bull. 30 24 Zittfll, Dr., 80. Zoanthcria perforata, 7B, Zoologio r6sum6, 62. (1095) m !■• Mm i' 'U 1 ■il \i\ mm I' M Slip', Si' v -m ! I», "« A-DVERTISKIVLTCNT. [iJullotin No. 30.] Tilt pulilicatioDs of the United States Geological Survey are iHHueil in accorilaiice with tlio statute, approved Marcli 11, 1871), wliifli declaroB that — " The iiublicatiouHot' the Geological Survey nlmll coiiHist of I he a:iuuHl rejjort of oiienitioiis, acdloirical iiud t'uciuouiic luapH illuHtratiui; the rcsourccH and I'laHHitleation of the IuikU, and reportn ii|iiiii general and ccondiuii'. ;:«olo!;y and prtliMintoliitiy. The annual report of operutuin.s of llii' (ie(doi.'ioal .Survey shall accomp:iny the annual report of the Secretary of the Interior. All upeeial nienioirs and reports of said Survey shall be iHSiied In uniform (piarto series if deemed ueeeH.siiry by th(( l)ire(^tor, hot ot hiM- wlae in ordinal j octavos. Tlireo thousand copies of «rtch shall be pnt)li«lM'd for scieiitiflc exehanjji's and for sale at t!u! price of ))ublication; andallliterary and carto;;raphir inateiials rectivedin ex;ur Muuozoic Flora of Vir^^lnla, by William M. Fontaine. — Report on the Denver Coal Basin, by Samuel F. Emmons. — Report on Ten-Milo Mining District, Colorado, by Samuel F. Emmons. — Report ou Silver Cliff Mining District, by Samuel F. Emmons. — Flora of the Dakota Gronp, by J. S. Newberry. BULLETINS. The Bnllutinit of the Survey will contain such papers relating to the general pnrpose of its work as do not properly come unilerthe heads of Annual Reports or Monographs. - Kach of those Bulletins will eoutain but one paper and will be complete in itself. They will, how- ever, bo numbered in a coutinuouH series, and will in time be united into volumes of convenient sizes. To facilitate this, each Bulletin will have two pagination-^, one proper to itself and uuotherwblch be- longs to it us part of the volume. Of this series of Bulletins Nos. 1 to 30 are already published, viz : 1. On Uyperstbene-Anilesite and on Triclinic Pyroxene in Augitie Rocks, by "!^^hitman Cross, with • GeologiealSkotehofBuiruloPoaks, Colorado, by 8. F. Emmons. 1883.8°. 42i)p, 2 pi. PricelOceuts. 2. Gold and Silver Conversion Table.s, giving the coining value of troy ounces of line metal, (to,, by Albeit Williams, jr. 18i«. 8°. ii, 8 pp. Price 5 cents. 3. On the Fossil Faunasof the Upper Devonian, alongtho meridian of 70° 30', from Tompkins County, New York, to Bradford County, Pennsylvania, by Henry .S.WiilianiH. 18Si. 8°. .30 pp. Price 6 cents. 4. On Mesozoic Fossils, by Charles A. White. 1884. 8°. 30 pp. 9 pi. Price 5 cents. 5. A Dictionary of Altitudes in the United States, compiled by Henry Gannett. 1884. 8°. 325 pp. Price 20 cents. 6. Elevations in the Dominion of Canada, by J. W. Spencer. 1884. 8°. 43 pp. Price 5 cents. 7. Mapoteoa Geologica Americana. A catalogue of geological maps of America (North and South), 1752-1881,by Jules Marcou and John Belknap Marcou. 1884. 8°. 184 pp. Price 10 cents. 8. On Secondary Enlargements of Mineral Fragments in Certain Rocks, by R. D. Irving and C. R. Van flise, 1884. 8°. 56 pp. 6 pi. Price 10 cents. 9. A Report of work done in the Washinzton Laboratory during the fiscal year 1883-'84. F. W. Clarke, chief chemist; T. M. Chatard, assistant. 1884. 8°. 40 pp. Price 5 cents. 10. On the Cambrian Faunas of North America. Preliminary studies, by Charles Doolittle Walcott. 1884. 8°. 74 pp. 10 pi. Price 5 cents. 1 1. On the Quaternary and Recent Mollusca of the Great Basin ; with Descriptions of New Forms, by K. Ellsworth Call; introduced by a sketch of the Quaternary Lakes of the Groat Hasiu, by G. K. Gil- bert. 1884. 8°. (16 pp. 6 pi. Price 5 cents. 12. A Crystallographic Study of the Thlnolite of Lake Lahontan, by Edward fe. Dana. 1884. 8° 34 pp. 3 pi. Price 5 cents. 13. Boundaries of the United States and of the several Stales and Territories, by Henry Gannett, 1885. 8°. 135 pp. Price 10 cents. 14. The Electrical and Magnetic Properties of the Iron Carburets, by Carl Barus ami Vincent Strouhal. 1885. 8°. 238 pp. Price 15 cents. 15. On the Mesozoio and Cenozoio Paleontology of California, by Dr. C. A. White. 1885. 8°. 33 pp. Price 5 cents. 10. On the higher Devonian Faunas of Ontario County, New York, by J. M. Clarke. 1885. 8°. 86 pp. 3 pi. Price 5 cents. 17. On the Development of Crystallization In the Igneous Rooks of Washoe, by Arnold Hague and J. P. Iddiugs. 1885. 8°. 44 pp. Price 5 cents. 18. Ou Marine Eocene, Fresh- water Miocene, and other Fossil Mollusca of Western North America, by Dr. C. A. White. 1885. 8°. 26 pp. 3 pi. Price 6 rents. 19. Notes on the Stratigi'aphy of California, by George F. Becker. 1885. 8°. 28 pp. Price 5 cents. ADVERTISEMENT. 1 Charlos Marth. roTnda,by brael F. Booker, iolaurt D. Irving. 086 of its work as Tlioj' will, how- cunvonient nizes. mother which bf- traan Cross, with )1. Price 10 cents, ne motal, ( tc, by ['ompklnsOounty, ). Price 5 cents. Its. .8«4. 83. 325 pp. ■ico 5 cents, orth iind South), cents. Irving and C. R. 1883-'84. F. W. (oolittle Walcott. f Now Forms, by liu, by G. K. OU- :)nna. 1884. 8° I Henry Gannett, rus and Vincent IsSS. 8°. 83 pp. lurke. 1885. 8°. lnold Hague and l^orth America, Prim 5 cents. 90. Contribntions to the Mineralogy of the Rocky Mountains, by Whitman Crou and W. F. niUe- brmnd. 188S. 8°. 114 pp. 1 pi. Price 10 cunts 21. Tho Lignites uf tlie Urwkt Sioux Keservatlun, by Bailey WUlia. 1885. 8°. 16 pp. b pi. 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The Physical Properties of tho Iron Carburets, by Carl Barus and Vincent Stroubal. 36. The Subsidence of small particles of Insoluble Solid in Liquid, by Carl Barus. STATISTICAL PAPERS. \ fourth serios'of publications, having special reference to the mineral resonrces of the United States, has been undertaken. Of that series the following have been published, viz : Mineral Resources of the United States [1882], by Albert Williams, jr. 1883. 8°. xvli,813pp. Price 50 centH. Mineral Resources of the United States, 1883 and 1884, by Albert Williams, Jr. 1885. 8°. xiv, 1,016 pp. Price 60 cents. In pre|)aration : Mineral Resources of the United States for calendar year 1885, by Albert Williams, Jr. Correspondence relating to the publications of the Survey, and all remittances, which must be by POSTAL NOTK Or MONBY ORDBH (not stamps), should be addressed To THE DiHECTOB OK THK Unitkd States Gkoi.ogicai. Suuvkt, . Washington, D. C. Wabhinotok, D. C, September 1, 1886.