SG. aoe P sca ie a P=s— Ce eee
A
DEPARTMENT OF THE INTERIOR
MONOGRAPHS
OF THE
UNITED STATES GEOLOGICAL SURVEY
VOLU NERV EI
GOVERNMENT PRINTING OFFICE 1884
UNITED STATES GEOLOGICAL SURVEY J. W. POWELL DIRECTOR
“Yu S
NH PALEONTOLOGY
THE EUREKA DISTRICT
By CHARLES DOOLITTLE WALCOTT
DEPARTMENT OF THE INTERIOR, Unirep States GEOLoGIcaL SuRVEY, Washington, D. C., June 1, 1884.
Sir: Herewith I have the honor to transmit a report on the inverte- brate fossils of the Paleozoic rocks of the Eureka District, Nevada.
I am greatly indebted to you for the personal interest you have taken in the work and generous facilities given me, both in the field and office, in carrying on the earlier part of this investigation.
I am also under many obligations to Hon. J. W. Powell, Director of the Geological Survey, for the opportunity afforded me to continue and enlarge the work after the completion of the original report.
Very respectfully, CHARLES D. WALCOTT.
Mr. Arnoutp Hacue,
Geologist in Charge.
Unitep States GEoLocicaL SuRVEY, New York, June 4, 1884.
Sir: I have the honor to transmit herewith the report of Mr. Charles D. Walcott on the ‘Paleontology of the Eureka District.”
The publication of Mr. Walcott’s monograph marks an era in the his- tory of the Paleozoic paleontology of the Far West. Heretofore the col- lections of fossils obtained have been in most instances small, incomplete, and hastily gathered from more or less widely separated localities. If the species obtained proved sufficient to determine the geologic horizons for the purpose of comparative study, little more was expected.
Now we possess the results of a careful survey of a district with a rich fauna, through 30,000 feet of Paleozoic strata, representing the Cambrian, Silurian, Devonian, and Carboniferous rocks.
Mr. Waleott’s intimate knowledge of the geological and structural features of the district lends additional weight to his own special labors. I regard his report as the most important contribution yet made to the invertebrate paleontology of the Basin Ranges, and of great value in its bearings upon the geology of the Cordillera, which under your guidance we are gradually working out.
Very respectfully, your obedient servant, ARNOLD HAGUE, Geologist in Charge.
Hon. J. W. PowELt,
Director United States Geological Survey, Washington, D. C.
vii
PREFACE.
This volume includes a report on the fossils collected during the field season of 1880 by the members of the Geological Survey of the Eureka District, transmitted for publication May 1, 1882, and additional observa- tions and descriptions resulting from the study of collections made under the immediate direction of the writer in the summer of 1882. Eleven plates of illustration and nearly double the amount of text originally transmitted have been added, and the character of the report slightly changed. ‘The reader will pardon the slight confusion in the arrangement of the plates resulting from this, and also the difference in the mode of illustration.. The system of Using wood-cuts is of great advantage, as it offers an opportunity to all for obtaining copies of the original figures by electrotyping. This is the first extended trial of the method for fine, detailed illustration, and is attempted at the special request of Major J. W. Powell, Director of the Survey.
In the preparation of the original report, frequent reference was made to the well-known Hall collection of Paleozoic fossils in the American Museum of Natural History, through the kindness of the curator in charge, Prof. R P. Whitfield, to whom I am indebted for valuable assistance. Prof. James Hall generously gave access to the material he had accumulated for the study of the corals and lamellibranchiate shells of the Devonian, and also aided me in my comparisons between the New York and Nevada speci- mens. Acknowledgment is due Prof. Samuel Calvin and Dr. J. P. Farns- worth, of the State University of Iowa, for the use of specimens for com- parison. The skill and care exercised by Mr. G. B. Simpson in preparing the drawings for plates ix to xx, inclusive, and by Dr. J. C. McConnell for plates i-vili, xxii-xxiv, inclusive, is shown in the plates illustrating . this report.
C.. DEW.
ix
CONTENTS.
Letter of transmittal to Mr. Arnold Hague, by the author .---. ...............22.-..--.--.-- eee Letter of transmittal to the Director, by Mr. Arnold Hague .. ..........-...2.2...----.------- vii LEREHENES) sco doc,co quod cranes sed Headey 945 go 46550 sacors 06 cancial rere Ss USseonecaraoeeeeeeaneese oe ix SMA OW DOSE) coceecacéardocicose ces stonacc h EEae ame he Hane Bene senses sade Sano S en AEeERe 1 Hossilsro fat hel atnb rl mame ce. eae eres Ae eee a 22). os Nc SUNY CLL eee 11 OhseryationsronOlenel usr owellessiae = We eee oars fi ota cake cain cee coe ne ate esos ReeR oe 32 HORSUS Obie LOWED SILURIAN: srs eee ns eereaate ee ok ahem noite ccm cceekieea ames toc cee 65 HBRBE STOP RU ONDE VODA socom ro sak ce eee eee © ape eas claire Sinisa wares Hacclee cate a teaals tea oe ee 99 Fossils of the Carboniferous .....-.....-.-...------ aC eee MEE A to ee ns Coen, oP 212 PN SLOILM ICH IS (OSS PECIOS 6.0.0 ofertas iain eee sen eT ear tte en 268 Paleozorcwsectionvin Central: Nevada... = sis ss see see eee oe ones eee soe eet e nee cece 283 JING BSS boos agiasoa pee SOMCH SOs Be A eR EEO ACH sce ithe Shs Soccer Se SCC ener ear ae mee 286
ILLUSTRATIONS.
PLATE I.—Cambrian and Silurian fossils. = II.—Devonian fossils. III.—Devonian fossils. 1V.—Devonian fossils. V.—Devonian fossils. ViI.—Devonian fossils. VII.— Carboniferous fossils. VIII.—Carboniferous fossils. IX.—Cambrian fossils. X.—Campbrian fossils. XI.—Siuurian fossils. XII.—Silurian fossils. XIII.—Devonian fossils. XIV.—Devonian fossils. XV.—Devonian fossils. XVI.—Devonian fossils. XVII.—Devonian fossils. XVIII.—Carboniferous fossils. XIX.—Carboniferous fossils. XX.—Carboniferous fossils. XXI.—Outline figures of Olenellus and Lingula. XXII.—Carboniferous fossils. XXIII.—Carboniferous fossils. XXIV.—Carboniferous fossils.
PRE cen le CRORS-St CHLOMLON Ont RO COURSE acme iain aoe ele earl omnia oleae eee ee lee aime aii aioe 2.—Cross-section of Orthoceras .........-..---.---------.---- S80505 cosS S056 Bsepsn Gscess Si SECUON OL -DELlerOphOn MaAjUSCULUB) <<< = oman wmlewie mani ee noes anise alsciviee d= eccccewss aie 4—Onthne-ficure of Ampullaria ?’ Powelli ....---= .-=-c-cs-ses escc se - scene fone e oe seen =- ea CO PERC UMUMILOLEA TDL tO aie EF OWELUD cin nar = = remain emia slo eerie a mlminl om ohn ie misisin ie dae ee G-—OvTiIME cue One MYSie UI ECH 3 cce clin makin teintetentele alate eile lolleara = oier alas mos, =iniclol ete 1a = eis 7.— Outline figure of Zaptychius carbonadiia@ .-2--- 22-22. nnn cae ae none e wee e ee eceaes aeace
aon
PALEONTOLOGY OF THE EUREKA DISTRICT.
BY CHARLES D. WALCOTT.
SUMMARY OF RESULTS.
The general character of the fauna of the Cambrian, Silurian, Devo- nian, and Carboniferous strata of the Eureka and White Pine Mining Districts of Central Nevada is given in this report more to illustrate the stratigraphic succession and equivalency of the geologic horizons with those described elsewhere than as a detailed monograph of the inverte- brate fossils; since, for the latter purpose much more extensive collec- tions are necessary to represent the large fauna of the Paleozoic system ot Central Nevada than we have at present.
As an assistant geologist in the field-work, the writer collected most of the fossils in situ, and studied their mode of occurrence and stratigraphic relations, thus disposing of an element of uncertainty which frequently arises in the mind of the paleontologist when examining collections from a region unfamiliar to him, and which presents, in the strata of the lesser divis- ions of its great geologic series of rocks, associations of species unknown elsewhere or an unusual vertical range of individual species. The presence of the Trenton species Orthis testudinaria in the upper portion of the lower half of the Pogonip Group in association with the genera Ptychoparia, Dicellocephalus, and Asaphus, is a typical example. Other illustrations of unusual association of species will be given in speaking of the Devonian
fauna.
2 PALEONTOLOGY OF THE EUREKA DISTRICT.
In the lowest fossiliferous stratum of the Cambrian in the District an interesting species of the genus Olenellus, O. Howelli, occurs that exhibits several abnormal features of development, and also certain embryonic characters that show the relation of the genus to the genus Paradoxides. Considerable space is given to the description and discussion of this species, and also a plate of outline figures to illustrate its variations and relations to other species. he specific identity of two of the three species of Olenel- lus, with O. Gilberti and O. Howelli from Pioche, Nevada, 130 miles distant, and their close resemblance to the species of Olenellus occurring in Ver- mont and Newfoundland, closely unites the faunas of the widely-separated localities, and aids materially in the correlation of the different groups form- ing the Cambrian system on the North American continent.
The Lower Cambrian type of the Conocephalidz is represented by Ptychoparia Linnarssoni and P. Prospectensis ; and the subgeneric groups of the genera usually occurring in the Potsdam Group are prominent in the fauna of the upper portion of the Cambrian. In Protospongia fenestrata we have a very simple and peculiar form of silicious sponge that is probably identical with the Cambrian species of St. David’s, Wales.
Much remains to be done with the small brachiopods of the Cambrian and Lower Silurian, since from their minute size and the imperfect state of preservation of the specimens collected, correct generic and specific refer- ences are very difficult. The one species of the genus Graptolithus in the upper portion of the Pogonip (Quebec) Group is the only trace discovered at this horizon in the Eureka District of a fauna which the writer in 1882 found quite extensively developed in the Pinon Range to the north. The Graptolites from Belmont, Nevada, that were described by Dr. C. A. White and referred by him to the Utica slate horizon of the Trenton Group (Expl. and Surv. West of 100th Merid., vol. iv, part 1, p. 10), are probably from the horizon of the Quebec Group, or the Upper Pogonip of the Eureka section.
The succession in the faunal series from the Olenellus (or Middle Cam- brian) fauna, through a large, well-defined fauna of the character of that of the Potsdam Group of New York and the Mississippi Valley, to one that in its assemblage of species combines both Cambrian and Silurian types and
passes upward into a fauna comparable to that of the Quebec Group, or the
SUMMARY OF RESULTS. 3
Calciferous and Chazy Groups, is of special interest. The transition from the Cambrian to the Silurian fauna is very gradual, and such as would occur where there was no marked physical disturbance to influence the faunal change resulting from the natural dying out and development of species or the influx of new species from other areas.
Of the species occurring below the passage beds three are identical with species occurring in the Potsdam sandstone of Wisconsin, viz: Hyo- lithes primordialis, Dicellocephalus Osceola, and Ptychaspis minuta; one with Acrotreta gemma of the Calciferous formation of Newfoundland; and Pty- choparia Oweni is a common species of the Potsdam horizon in Montana and Dakota. These specific identifications and the great development of species of the genera Agnostus, Dicellocephalus, and Ptychoparia, in the middle and upper portion of the Cambrian section, furnish abundant evi- dence upon which to correlate the fauna and the geologic horizon at which it occurs with the Potsdam fauna and formation, as was done by Messrs. Hall and Whitfield (Geol. Expl. Fortieth Par., vol. iv, p. 199, 1877). Of the Potsdam fauna eleven genera and fifteen species continue on into the passage fauna, viz (species of the Potsdam fauna are printed in italics): Lingulepis Mera, L. minuta, Lingula? manticula, Discina (sp. undt.), Acrotreta gemma, Schizambon typicalis, Obolella ambigua, O. discoidea, Leptena Melita, Orthis Hamburgensis, O. testudi- naria, Triplesia calcifera, Tellinomya ? Hamburgensis, Agnostus communis, A. bidens, A. Neon, Dicellocephalus finalis, D. inexpectans, Ptychoparia ? annectans, Ptychoparia affinis, P. granulosus, P. Haguei, P. Oweni, P. unisul- catus, Arethusina Americana, Amphion (sp. undt.), Barrandia McCoyi, Ile- nurus Eurekensis, Asaphus Caribouensis.
In the next superior grouping, about midway of the Pogonip Group, all the middle Cambrian genera, with the exception of Orthis and Ilenurus, have disappeared, and higher up the genera Receptaculites, Cheetetes, Pleurotomaria, Maclurea, Cyphaspis, Bathyurus, and Asaphus carry the fauna up to the summit of the formation where the genera Receptaculites, Ptilodictya, Cheetetes, Strophomena, Orthis, Tellinomya, Modiolopsis, Ma- clurea, Cyrtolites, Orthoceras, Endoceras, Coleoprion, Leperditia, Beyrichia, Amphion, Ceraurus, and Asaphus give it a facies approaching that of the
4 PALEONTOLOGY OF THE EUREKA DISTRICT.
Lower Trenton and indicating an horizon that is considered to be in a measure the equivalent of that of the Chazy formation of New York and Canada. The fauna of the lower portion of the Pogonip Group corre- sponds in the same manner to that of the Calciferous sand-rock of the same region. The large number of individuals of the species of Receptaculites, R. mammillaris especially, gives the fauna of the upper beds a character that this horizon has not hitherto had. This, united with several of the Trenton species, viz, Orthis testudinaria, O. tricenaria, O. perveta, Tellinomya contracta, two species of Modiolopsis allied to Trenton forms, and Raphis- toma Nasoni, strongly foreshadows the opening of the Trenton period.
The fauna between that of the Pogonip and the Devonian horizon is so meager that the only reference made to it is in the systematic list and in the lists of the geologic report (Geology of the Eureka District). As the determination of a higher Silurian horizon than that of the Trenton-like ~ fauna in the limestone above the quartzite capping the Pogonip Group rested mainly on the presence of the genus Halysites, the opinion of Prof. James Hall was requested as to the generic relations of the specimens that had been referred to Halysites in the field. While he did not say positively that the form represented was Halysites, he expressed the opinion that it was of organic origin, and that he knew of nothing else but Halysites to which it could be referred. This conclusion has since been fully proven by the discovery of fine specimens of Halysites catenulatus at the same horizon in the White Pine District, Nevada, associated with specimens in a similar state of preservation as those from Lone Mountain.
The fauna of the Devonian is large and representative, notwithstand- ing some speciés have reversed their relative position in the group as they have been known heretofore, and othersshave a greater vertical range. Among the brachiopods, Orthis Tulliensis, of the Tully limestone of New York State, is found at the summit of the Devonian limestone, and Orthis impressa, 1 Chemung species of New York, at the base, associated with eastern Upper Helderberg limestone species; and a variety of Atrypa reti- cularis, characteristic of the Niagara limestone, and unknown heretofore elsewhere, occurs with the former in the upper beds. Among the corals, Cladopora pulchra, Syringopora Hisingeri, and Cyathophyllum corniculum, of
SUMMARY OF RESULTS. 5
the great Corniferous coral reef of the east, occur at the upper horizon, and Syringopora perelegans, of the same formation in New York, ranges through- out the group in Nevada. The occurrence of rare species and those of limited range in the eastern Devonian is not an unusual feature, as we find Lingula Lena, Strophodonta Patersoni, Chonetes hemispherica, Productus truncatus, ete. The Trilobita also show the great range of the two species heretofore regarded as restricted to certain localities, viz, Proctus Halde- mani and P. marginalis, and also the more widely distributed Phacops rana. Among species of a greater range there is the well-known Pterinea flabella in association with other forms of the Upper Helderberg formation at the Lower Devonian horizon; and Sanguinolites rigidus and S. ventricosus, of the Chemung Group, occur in the upper beds of limestone. The Gasteropoda are shown by Platyostoma lineatum, so abundant in the Hamilton formation of New York, and eight species of Platyceras, five of which are identical with eastern species, as are the four species of Tentaculites and the minute Styliola fissurella representing the Pteropoda.
The fortunate discovery of the interior of a dorsal valve of a rather large species of Lingula, L. Whitei, affords the means of comparison of the same parts of the shell with a Silurian and recent species of this genus, and proves the great structural similarity of the three species so widely sepa- rated in geologic time (Plate xxi, figs. 18, 19, 20).
The fauna of the White Pine shale in the White Pine District is in
many respects a peculiar one, combining as it does species ranging from the
e
Middle Devonian into the Lower Carboniferous. The stratigraphic position of the shale is at the summit of the Devonian system and at the base of the Carboniferous; it is overlain in the Eureka District, where the section is unbroken, by a massive belt of conglomerate before the limestones carrying the Lower Carboniferous fauna appear in the section. The strongly- marked Carboniferous species are, Spiriferina cristata, Retzia radialis, Athyris sublamellosa, and Cardiomorpha Missouriensis ; these are associated, at the same horizon, with such Devonian species as Discina Lodensis, Productus subaculeatus, Amboccelia umbonata, Rhynchonella (L.) quadricostata, Aviculopecten catactus, and Lunulicardium fragosum.
Messrs. Hall and Whitfield (Geol. Expl. Fortieth Par., vol. iv, p. 201)
6 PALEONTOLOGY OF THE EUREKA DISTRICT.
considered Cardiomorpha Missouriensis aud fragments of a Spirifera of the type of Spirifera Rockymontana Marcou (=S. Keokuk Hall), as probably indicating a division of the black shales into Carboniferous and Devonian, but, from field observations and the assemblage of fossils, such a division is incompatible with the facts. The White Pine shales occupy the same position with relation to the Devonian and the Carboniferous systems as does the lower portion of the Pogonip limestone to the Cambrian and Silu- rian systems. In each case there are beds of passage carrying a fauna that unite the faunas of the two systems.
That the Devonian portion of the White Pine shale fauna is more nearly related to that of the shales of the Hamilton Group than that of the Chemung horizon, as found in the neighboring Eureka District, is owing undoubtedly to the character of the environment of the fauna during the deposition of the shales, a feature so well shown in the recurrent faunas of the Devonian of New York as studied by Prof. H. S. Williams.
A summary of the Devonian fauna is given in the following table:
| Common to Nevada | - and— | Nevada. SSS SSS | | Falls | New York.| of Iowa.) | | Ohio. | Cjass. | A : H j Ailes | | a 2 aah ie) tate 1 ° papesee tee | | o | o a 5 | doce (UR BS Saleem tee eeeallte 5 a 5 by B = a= pa = 2 3} 2 2 2A 2 S CS) = Ea aon Setlists ear Neral aes | & wird} Pp |b to) D nm | Poriferays ss atte one eae B | sie at 1 PU eseeran | ee | eens OAC TINOZOR ese eenn an eee 1A 127) 15 13 1 11 i 9; 3 | Roly zm soe - cass cen user 2 3 BY Baste 2a DA Wises etn | Bee ees reat | Brachiopoda.-..-.-......- 26/ *883/ 50) 51 18| 26) 38 8] 11 Lamellibranchiata .-....... 29))' 42))| 227 17 | 2 27 9 2 2 | .Gasteropoda.............-. 13| 39!) 93| 47 A ates 2 Quon | le teropod a)ecesen == cece == 5 8 7 2 1 5 EP ease conc | Cephalopoda. - ei) atl 7 4 fi hereae ecko | Lon eG peosch ee oes Seeds | 2 | 2 PM aeeace| ke s5e C1 Mpsoee| Sere sels se | Peecilopoda.......-.-...--. 4 7 4 Billeseeen 4 Bi oe | 2 ee a eS Ss ees ee | Motalteossanien sceeie- 102 | 225| 141| 108| 24] 94 799|) moh | mien | | |
* And five varieties.
Of the two hundred and twenty-five species, sixty-one are described for the first time, forty-five species are referred to genera but not specifi-
~
SUMMARY OF RESULTS. 7
cally named, and one hundred and nineteen species are identified with species already known; of the latter, seventy-nine are identical with species found in New York State; eleven species occur in Iowa that are unknown in New York, and the remaining species occur in various localities both in the Rocky Mountains and the central and eastern portions of the continent. The stratigraphic position of each species is given in the systematic list at the close of the descriptions.
The Upper Helderberg horizon of the New York series is represented by thirty-eight species common to it and the lower portion of the Devonian of the Eureka District; the Chemung Group of the same by sixteen species; of the Hamilton species of New York, twenty-three are distributed through the lower portion of the Eureka Devonian limestone and eighteen species in the middle and upper portions, but not in such a manner as to distinguish a middle division corresponding to the Hamilton formation of New York. Of strictly Hamilton species in New York, twenty-three are found, of which eleven are in beds a little below the summit, and twelve just above the base of the formation. F
Of ichthyic remains there is but one Ctenacanthus-like tooth. This with asingle tooth of the genus Cladodus, brought from near the Hot Springs of Humboldt Canon, by the geologists of the Fortieth Parallel Survey, is all that-is known of this fauna in Central Nevada, although from the pres- ence of a strongly-marked horizon of Devonian fishes in the Kanab Canon of Northern Arizona, it is a little remarkable that so few specimens have been discovered to the north, where the formation has a much greater devel- opment.
With the exception of a species of Psilophyton, a fragment of Cordaites, and a few obscure fucoidal remains, the flora of the period is unrepresented, although in the upper beds the conditions necessary for the preservation of vegetable remains appear to have been favorable.
The Devonian corals as well as those of the Silurian and Carbonifer- ous are not illustrated, and only short notes are given of a portion of the twenty-seven species occurring in the Devonian. From what is already known of this portion of the fauna, there is little doubt but that future col- lections from the area of the Great Basin will give a very complete series
8 PALEONTOLOGY OF THE EUREKA DISTRIOT.
of speciés, and still further increase the number of species common to the eastern and central (or Atlantic and Mississippi) areas and the western or Rocky Mountain area.
The fauna of the Upper Carboniferous limestone is composed of old and well-known species usually occurring at that horizon, and gives but three species new to the region of the Rocky Mountains, viz, Ptilodictya carbonaria, P. serrata, and Macrodon tenuistriata. 'The comparatively few species occur- ring in the middle and upper portions of the Lower Carboniferous Group are also well-known forms, but at the lower horizon we meet with a most interesting assemblage of species. It embraces a large number of Lamelli- branchiate shells, a class so rarely represented in collections from this region, and unites the characters of the fauna of the Lower Carboniferous groups of the Mississippi Valley with that of the Coal-Measures in a remark- able degree, a feature not uncommon in the Lower Carboniferous of the Rocky Mountains, but rarely so well shown as in the Eureka District.
There is also a certain commingling of Upper Devonian species with the Lower Carboniferous fauna. We find Discina Newberryi, Macrodon Hamiltone, Grammysia Hannibalensis, G. arcuata, Sanguinolites Afolus, and Pleurotomaria nodomarginata associated with common Carboniferous species.
The discovery of Pulmoniferous mollusks of the genera Physa and Zaptychius in association with the fresh-water shell Ampullaria? Powelli and fragments of a flora, coniferous in character, supports the stratigraphic evidence of the presence of a near or not distant land area at the time of the deposition of the Lower Carboniferous rocks of Central Nevada. It also gives the first notice of the occurrence of the Pulmonifera in rocks of this age; the land shells of Nova Scotia and Illinois occur in the Coal- Measures, and Strophites grandeva, Dawson, is from the Devonian plant beds of New Brunswick. The bearing of this discovery on the question of the presence of land areas from the time of the Middle Paleozoic to the present is important. No other explanation offers than that there was a con- tinuous fresh-water habitat, ponds or streams, which permitted the genera to descend in a direct line from Paleozoic time to the present.
The grouping of the genera and species in the strata is shown ina general manner in the systematic list at the end of this volume, and in
=
SUMMARY OF RESULTS. 3]
greater detail in the abstract of a report on the geology of the Eureka District, Nevada, by Mr. Arnold Hague, contained in the Third Annual Re- port of the Director of the United States Geological Survey.
In the accompanying table the number of genera and species known at present in the Paleozoic formations of Central Nevada is given:
sc c*) =| 2 ; | 3a 8 3 lead A 2 S + 6 oe no i Geologic horizons. >e| 2 a aa aea| § & a ® sa = o Be leases) a=) aes | is ei ecolees Salas o a = SO HE) 5 o am | A =) a = Samal Cambrian: -\.c- 5-2 -- sss 24 69} 32 31 CWhescese Silurian : | Pogonip eos sece: ee |-47| 99] 34] 31| 34] 16 Trenton, etc ..-.--...- 14 15 | eee }) 1a |eseee Devonianees esas ee 102)} 225 119)| 61} 45 ].-.... Carboniferous .-........... 65 | 132 53 50 | 29 3 Motalysse eae ee 252] 540] 242] 173! 125] 18 Meackrrenties- dace eee 8 18 DE esse Seneca ee ee: Potal cenccac-se eee 244 | 522) 224] 173] 125 |..-...
HOSS fs Om eH CAMB RIAN. PROSPECT MOUNTAIN GROUP. PORIFERA.
Genus PROTOSPONGIA Salter. Protospongia fenestrata Salter. Plate ix, figs. 5, 5 a, b.
Protospongia fenestrata Salter, 1864. Quart. Jour. Geol. Soc., vol. xx, p. 238, pl. 13, fig. 12 a, b. Ibid., Cat. Cambrian and Silurian Fossils, p. 3, 1873. Hicks, 1874. Quart. Jour. Geol. Soe., vol. xxvii, p. 401, pl. 16, fig. 20. Zittel, 1877. Abh. der K. bayer. Akademie der Wiss. 2 Cl., xili; Bd. “Studien ii, fossile Spongien” (p. 45, sep. copy). Carter, 1877. Ann. and Mag. Nat. Hist. ser. 4, vol. xxv, p. 177. Brégger, 1878. On paradoxidesskifrene ved Krekling. Sep- arataftryk af Nyt Magazin for Naturvidensk. vol. xxiv. ity oy 20, t. 6, f. 14.
Sollas, 1880. Quart. Jour. Geol. Soc.. vol. xxx vi, p. 362, figs. 1: 2
Roemer, 1880. Leth. Geogn., 1 Th. p. 316, f. 59.
Hinde, 1883. Cat. Fossil Sponges, p. 129, pl. xxviii, fig. 2.
Mr. Salter originally described this interesting sponge as having a loosely reticulate skeleton formed of very large cruciform spiculz, the branches of which cross each other at an angle of 80°, and only in one plane, no ascending or descending branches rising from the point of con- junction. The angles occasionally vary, but not much.
More perfect specimens obtained by Dr. Hicks show the spiculze to be quadriradiate, slightly raised at the center and formed of four nearly cylin- drical rays.
The skeleton, as described by Mr. Sollas, is composed of large primary
spicule with the interspaces filled in by three series of spicule, each u
-
12 PALEONTOLOGY OF THE EUREKA DISTRICT.
formed of spicule smaller than those preceding it, their rays all lying regularly disposed in two directions at right angle 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 different sized spicule lying scattered on the surface of the limestone shale or crowded together without any regularity to the direction of the rays or the size of the spicule. The spicule, 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 crowded together by accident would form a skeleton similar to that described by Mr. Sollas. The under side of the spicule show no trace of a fifth ray or its point of attachment, appearing in this respect like the upper side, except that the surtace is a little concave instead of convex as on the upper side. They are silicious, and differ in mineral character from the spicule from the Cambrian rocks of Wales which have been replaced by pyrite.
Dr. Hicks states that P. fenestrata occurs in the Longmynd Group, in the Menevian Group, and also in the Upper Lingula flags to the base of the Tremadoc rocks, giving a vertical range of from 8,000 to 10,000 feet (Quart. Jour. Geol. Soc. London, vol. xviii, p. 181. 1872). It also occurs in black shales of Cambrian age in Norway and Sweden.
Formation and localities Cambrian, Prospect Mountain Group. In the mountain shale near the Eldorado mine, and in the Secret Caton shale on the east side of Secret Cation, Eureka District, Nevada.
BRACHIOPODA.
Genus LINGULEPIS Hall. Lingulepis Mera H. & W.
Lingulepis Mera Hall & Whitfield, 1877. Geol. Expl. Fortieth Parallel, vol. iv, p. 206, pl. i, figs. 5-7. The specimens referred to this species are specifically identical with the types collected by the geologists of the Fortieth Parallel Survey in the Eureka District.
FOSSILS OF THE CAMBRIAN. 13°
e
The species is well represented, and appears to be characteristic of the upper portion of the Cambrian and the lower horizon of the Silurian, Pogonip Group. It occurs in the Secret Canon shale of the Cambrian on the eastern side of the cafon directly east of Ruby Hill; in the limestone of the Pogonip Group northeast of Adams Hill; on the ridge southeast of the Jackson mine; on the southwest spur of Wood Cone, and southeast of the Hamburg mine, Eureka District, Nevada.
Lingulepis ? minuta H. & W. Lingulepis ? minuta Hall & Whitfield, 1877. Geol. Expl., Fortieth Parallel, vol. iv, p. 206, pl. i, figs. 3, 4.
This species has nearly the same vertical range and geographical distribution as Lingulepis Mera, usually occurring in the same localities. The type specimens were obtained in the Eureka District by the members of the Fortieth Parallel Geological Survey.
Genus LINGULA Bruguiére. Lingula ? manticula White.
Plates ix, fig 3, and xi, fig. 2. Lingula? manticula White, 1874. Expl. and Sury. West 100th Merid.; Prelim. Rep. Pal., p. 9. Lbid., vol. iv, pt. 1, p. 52, pl. iii, figs. 2a, b, 1875.
The range of variation among the specimens we have referred to this species is greater than exists between them and our conception of L. ? manticula, as obtained from the description and illustrations given by Dr. White, and without a direct comparison with the type specimens to determine any specific differences, if they exist, we consider them as one species. As none of the examples show the internal characters of the shell, the doubtful character of the generic reference remains unchanged.
The type specimens were collected in the Schell Creek Range of Ne- yada, at an horizon in the Silurian, equivalent probably, to the horizon at which the species occurs in the Pogonip Group. F
14 PALEONTOLOGY OF THE EUREKA DISTRICT.
Formation and localities—Cambrian, Prospect Mountain limestone, just beneath the Secret Canon shale, in the 700-foot level of the Richmond mine, Ruby Hill; at the summit of the Secret Canon shale in New York Canon; also in the lowest portion of the Pogonip limestone northeast of Adams Hill and higher up in the same group on the eastern slope of the ridge east of the Hamburg Ridge, Eureka District, Nevada.
Genus OBOLELLA Billings. Obolella discoidea H. & W.
Obolella discoidea, Hall & Whitfield, 1877. Geol. Expl. Fortieth Parallel, vol. iv, p. 205, pl. i, figs. 1, 2.
This is one of the species brought in by the geologists of the Fortieth Parallel Survey from the Eureka District. It occurs in the Hamburg shale of the Cambrian, and the Pogonip Group of the Silurian, on the ridge east of the Hamburg Ridge and at the Pogonip horizon in the lime- stone northeast or Adams Hill; also on the first ridge southeast of the Jack- son mine, Eureka District, Nevada; and in the Pogonip limestone on Pogo- nip Ridge, White Pine District, Nevada.
Genus ACROTHELE Linnarsson.
Acrothele? dichotoma, n. sp. Plate ix, fig. 11.
Shell of medium size, thin, corneous, nearly circular in outline, the transverse diameter being a little greater than the longitudinal.
Ventral valve depressed, discoid, with the apex but slightly elevated above the general plane of the surface and situated about one-third the distance from the posterior to the anterior margin. ‘The apex is perforate | and has a narrow groove around it, except on the posterior side, where a low vim alone separates the groove and the slightly-depressed pseudo:deltidial area, ‘This area is triangular in form, and extends to the posterior margin, gradually expanding toa width a little less than its length; it appears to have been quite minute at first just beneath the apex and to have been filled
FOSSILS OF THE CAMBRIAN. 15
in by successive additions of the shell, so that the general circular outline of the shell has scarcely been broken by the very slight truncation of the posterior margin. The additions to the posterior margin of the false area are crowded together as little transverse ridges with fine stria between.
The outer portion of the shell is largely exfoliated, but traces of ra- diating striz and concentric lines of growth are shown. The latter on the outer portion appear to have been continuous with those crossing the pseudo-deltidial area From each side of the apex a narrow, elongate, muscular scar gently diverges, extending towards the central portion of the shell. Transverse diameter, 7.5™; longitudinal diameter, 6.75"; eleva- tion or convexity, about 0.75™.
The reference of this species to the genus Acrothele is made with reser- vation, Its depressed form and eccentrically-perforated apex are similar, while the false area and the muscular scar are different. It is, however, more closely allied to Acrothele than with any genus with which we are acquainted,
Formation and locality—Cambrian, Prospect Mountain Group; upper beds of the Secret Canon shale, on the east side of Secret Canon, Eureka District, Nevada.
Genus SCENELLA Billings. Scenella ? conula, n. sp. Plate ix, fig. 6.
Shell small, conical; apex subcentral, apparently with a tendency to bend a little to one of the sides on which there is a very faintly-indicated line run- ning from the apex to the margin. Aperture ovate. Surface smooth to the unaided eye; it shows fine concentric striae and a few obscure lines of growth when examined by the aid of a strong magnifying glass.
Dimensions.—Greater diameter, 3"; lesser diameter, 2.25": eleva- tion, about 1.75™™.
This is a small Metoptoma-like shell, the generic reference of which is provisional, as it differs from the type of the genus, Scenella reticulata, in not having a carina running from the apex to the margin; the curvature of
16 PALEONTOLOGY OF THE EUREKA DISTRICT.
the apex is not positively known, as its summit is broken off in all the specimens in the collection.
The line from the apex to the margin is too strongly represented in the figure on plate ix.
Formation and locality—Cambrian, Prospect Mountain Group; low down in the massive limestone beneath the Secret Cafion shale on the east slope of Prospect Mountain, Eureka District, Nevada.
Genus ACROTRETA Kutorga.
Mr. Davidson, in his Classification of the British Fossil Brachiopoda, gives an accurate generic description of the external form and character of the valves of Acrotreta, but not having specimens showing the interior of the valves, he left the genus doubtfull-; as a subgenus of Siphonotreta. The fortunate discovery of a large number of specimens of Acrotreta gemma Billings, in the passage-beds between the Cambrian and Silurian limestones of the Eureka District, affords material for the study of the interior char- acters of the smaller valve, and also some of those of the larger or conical valve.
The interior of the larger valve shows a perforated, rounded, nipple- like projection extending down from the apex, plate 1, fig. 1/ This is well shown in the cast, fig. 1b. On each side a slight ridge extends obliquely forward. No other markings can be determined. In the smaller valve a strong median ridge extends from in front of a minute triangular space on the cardinal margin two-thirds the distance to the front margin of the shell. Just back of the center of the shell a small oval scar occurs on each side of the ridge, and near the cardinal margin another pair of larger crescentiform sears. A pair of lateral marginal scars are very faintly shown on two ex- amples. They are usually too indistinct to be recognized.
Comparing this interior with that of the smaller valve of Siphonotreta unguiculata, as illustrated by Davidson (Geol. Mag. N. S., vol. iv, pl. ii, fig. 11, 1877), the differences between them are well marked, especially in the greater spreading out of the muscular impressions in Acrotreta.
FOSSILS OF THE CAMBRIAN. 17
In the larger valves the conical form and siphonal tube strongly relate them. (See plate i, figs. 1b, 1/; and fig. 8.)
The interior of the smaller valve shows a wonderful similarity to that of Obolella ? Scabrine Callaway (Day. Mon. Brit. Foss. Brach., vol. v, pt. ii, p. 211, pl. xvi, fig. 27d), (see plate 1, fig. 1¢,) and I can hardly understand that they belong to separate genera. If the conical valve of 0.? Scabrine should be found to show indications of a perforate apex, the relations of the species to Acrotreta gemma would be very close.
Acrotreta gemma Billings. Plate i, figs. la, 1f, 1d-f; plate ix, figs. 9, 9a,
Acrotreta gemma Billings, 1865. Palaeozoic Fossils, vol. i, p. 216, figs. 201a, f.
Acrotreta subconica and A. attenuata Meek, 1873. Sixth Ann. Rep. U.S. Geol. Surv. Terr., p. 463.
Acrotreta pyxidicula White, 1874. Expl. and Surv. West 100th Merid., Rep. Invert, Foss., p. 9. Ibid., vol. iv, p. 53, pl. iii, figs. 3 a—d,.1875.
The specific identity of the forms from Nevada with those from New- foundland scarcely permits of question if based on the description and illus- trations given by Mr. Billings. Some specimeus have the conical valve more or less elevated, but the difference is not of specific value.
Dimensions of an average specimen: height of conical valve, 1.75™"; transverse diameter, 2"; longitudinal diameter, 1.75™.
The species from the passage beds between the Cambrian and Silurian faunas on the Gallatin River, Montana, doubtfully identified by Mr. Meek as A. subconica Kutorga, and in case of eventually proving to be a distinct species to be called A. attenuata, proves on comparison to be the same as the Eureka species, and it is also associated with Iphidea sculptilis, Agnostus bidens, and Ptychoparia Oweni, at each locality. The mesial furrow on the false area is a variable character, as also within somewhat broad limits the depres- sion or elevation of the conical valve. With the specimens before me for comparison, they are all referred to the one species and identified with A. gemma. Acrotreta pyxidicula White, from Nevada, occurs at about the same geologic horizon. The smaller valve is identical with that of A. gemma;
2c0DwWw
18 PALEONTOLOGY OF THE EUREKA DISTRICT.
the larger is greatly depressed, but there are examples uniting it with the more elevated valve of A. gemma.
Formation and localities —Cambrian and Silurian. At the summit of the Secret Cation shale in New York, and Secret Camions, and opposite the dump of the Richmond mine shaft, Ruby Hill; it also passes up through the shaly beds capping the massive Hamburg limestone belt into the beds of the Pogonip Group, on the ridge opposite the Hamburg mine; at about the same horizon northeast of Adams Hill, and on the ridge southeast of the Jackson mine, Eureka District, Nevada. The species was found in 1882 on Pogonip Ridge, White Pine District, Nevada.
Genus KUTORGINA Billings. Kutorgina Whitfieldi, n. sp. Plate ix, figs. 4, 4a.
Shell convex, hinge line straight and a little less than the greatest width of the shell, sides rounding regularly into the slightly convex frontal margin.
Ventral valve quite convex, elevated along the center to form a flat depressed fold, and sloping quite rapidly from this to the lateral and cardinal margins; median elevation with about five rather faintly-defined, simple plications that reach up to the higher portion of the valve; beak small, a little depressed, and rising above the area; cardinal margins straight and diverging from the beak at an obtuse angle; character of area unknown.
Dorsal valve depressed convex, with a rather wide, shallow, median depression, and two short plications on each side of it towards the front, which are obsolete in some of the specimens; the area between the cardinal edges and the elevation of the sides of the mesial depression is depressed and corresponds to the flattened lateral slope of the ventral valve.
Surface marked by fine, very clearly defined concentric striee subpar- allel to the front and lateral margins. The strize are crowded together into narrow ridges, giving the appearance mentioned by Mr. Billings as occur- ring on the type species of the genus.
FOSSILS OF THE CAMBRIAN. 19
This species is unlike any described that is known to me. In general form and surface characters it is allied to Kutorgina cingulata Billings, and is undoubtedly of the same genus if the shells illustrated by figs. 8 and 10, on page 8, of the “Paleozoic Fossils of Canada,” vol. i, are taken as types. The specific name is given in honor of Prof. R. P. Whitfield, the distin- guished paleontologist.
Formation and locality—Cambrian. Prospect Mountain Group, beneath the Secret Cafion shale, on the west side of Secret Cafion, Eureka District, Nevada.
Kutorgina Prospectensis, n. sp. Plate ix, figs. 1a, b.
Shell rather small for a species of the genus. It is thick and black, like a linguloid shell.
Ventral valve elevated, with the apex projecting over the triangular area and extending considerably beyond the posterior margin; owing to the exfoliation of the shell the extremity of the apex is unknown; the sur- face of the area is also unknown. Ventral valve depressed, slightly convex, without a mesial sinus; marginal outline subcircular, with the posterior margin obtusely angular at the beak; the beak is slightly depressed below the highest point of the shell, and apparently projects a trifle beyond the cardinal edge. Surface marked by strongly-defined fine concentric strie, ten in a distance of one millimeter, where they terminate on the posterior margin.
The dorsal valve of this species is much like that of Iphidea Labrador- icus Billings, but it does not appear to come within the limits of that genus as defined by the type species.
Formation and locality—Cambrian. In an arenaceous shale resting on the Prospect Mountain quartzite, summit of Prospect Mountain, Eureka District, Nevada.
20 PALEONTOLOGY OF THE EUREKA DISTRICT.
Kutorgina sculptilis Meek (Sp). Plate i, figs. 7, 7a, b; pl. ix, fig. 7.
Iphidea (? ?) sculptilis Meek, 1873. Sixth Ann. Rep. U.S. Geol. Surv. Terr. for the year 1872, p. 479. |
Kutorgina minutissima Hall & Whitfield, 1877. U.S. Geol. Expl. Fortieth Par., vol. iv, p. 207, pl. i, figs. 11, 12.
Shell minute, semicircular to subquadrangular; hinge line usually a | little shorter than the greatest width of the shell; sides slightly rounded; antero-lateral angles rounded; frontal margin gently convex or nearly straight along the middle. _
Ventral valve obliquely depressed, subconical, with the somewhat ob- tusely pointed apex on, or slightly extending over, the cardinal line; area vertical or bending a little backward, triangular; width a little more than twice the height, but not as broad as the shell, owing to the sides of the latter curving in to meet the straight area at an angle of about 50°; foramen (?) large, dorsal valve depressed convex, most elevated on the umbo; beak a- little depressed, scarcely projecting beyond the cardinal line; mesial sinus faintly defined, not much more than a slight flattening in many examples; area low, general characters unknown.
Surface of the shell marked by very fine, sharp, elevated, concentric lines, that coalesce or bifurcate irregularly, giving a peculiar, interrupted, wavy appearance under the magnifiér; these lines extend around on the sides of the posterior side or area to the edges of the triangular foraminal- like opening. Slightly irregular, slender, depressed or elevated interrupted lines radiate from the beak or apex; they vary in strength and number, and on some shells are scarcely discernible, although forming a prominent feature in many individuals.
Length of largest shell observed, 2.5"; breadth, lps depth of ven- tral valve, 1.25"; of dorsal valve, 0.5™™.
The type of Iphidea (??) sculptilis (Meek) is a strongly marked ventral valve of this species from the east side of the Gallatin River, Montana, where it is associated with Acrotreta gemma Billings, and Ptychoparia Oweni Meek.
FOSSILS OF THE CAMBRIAN. 21
In the Eureka District it is associated with the same species at the same relative geological horizon. I now have before me Mr. Meek’s type, and also the type of Kutorgina minutissima H. & W., from the Eureka District. They evidently belong to one species and do not vary from each other more than individuals from the same locality.
The generic reference of the species by Messrs. Hall and Whitfield is followed, as from all comparable characters the species is closely allied to the type of the genus Kutorgina cingulata Billings.
As yet no evidence has been obtained of the presence of a pseudo-del- tidium similar to that in Jphidea bella Billings. Mr. Meek failed to detect it in working away the matrix from the specimens he used, and the same is the case with the material from the Eureka District. From the fact that the pseudo-deltidium is often absent in specimens of a well-marked species allied to J. bella now before me, and the great similarity of the false area of the larger valves of it and K. sculptilis, when in that condition, I
strongly suspect that if we had more perfect specimens the concentric sur- face lines would not stop at the margin of the triangular space, but cross a pseudo-deltidium, as in Z. bella.
As stated by Mr. Billings, the genera Kutorgina and Iphidea are closely related to each other, and while it is convenient to have the two genera to refer such forms as K. sculptilis and Z. bella, with our present knowledge of the two genera, Iphidea cannot be considered as a well-established genus, although it is quite probable that if we had the interior of the shell of each form it would be necessary to distinguish them as Mr Billings has done.
Formation and localities —Upper Cambrian. ‘Secret Canon shale on the east side of Secret Canon; shaly limestone in passage-beds between the Cambrian and Silurian on the first ridge east of the Hamburg Mine, Eureka District, Nevada. Also, on the east side of the Gallatin River above Gal- latin City, Montana, as labelled in the collections of the United States Na-
tional Museum.
22 PALEONTOLOGY OF THE EUREKA DISTRICT.
Genus LEPT NA Dalman.
Leptezna Melita H. & W.
Leptena Melita Hall & Whitfield, 1877. Geol. Expl. Fortieth Par., vol. iv, p. 208, pl. i, figs. 13, 14.
This species is given by its authors as occurring in the Lower Silurian rocks of the Eureka District, the exact horizon being unknown. From the examples in the present collection we learn that it ranges from the limestone beneath the Secret Canon shale on the eastern slope of Prospect Mountain, up through the intervening strata to about 500 feet above the base of the Pogonip Group, at which horizon it is found on the ridge next east of the Hamburg Ridge; also southeast of the Jackson mine, and northeast of Adams Hill, Eureka District, Nevada.
Genus ORTHIS Dalman. Orthis Eurekensis, n. sp.
Plate ix, figs. 8, 8a.
Shell small, transversely suboval, strongly convex. The ventral valve is more convex than the dorsal, and elevated along the middle so as to be- come subcarinate; beak small; area unknown.
Dorsal valve convex, with a strongly marked median depression that gives it a bilobed character; beak short and apparently incurved over a low area.
Surface marked by about forty strong, simple, radiating strie that extend up to the beak.
Dimensions.—Transverse diameter, 4""; length of ventral valve, 3.5™™; of dorsal valve, 8"; depth of ventral valve, 1.5™"; of dorsal valve, about 1™™.
From the nature of the matrix the beaks of the valves are usually broken away with a portion of the shell on the summit, so that the cast of the hinge-teeth of the ventral valve and the muscular impressions of the dorsal valve are shown, as seen in fig. 8a, plate ix.
We know of no similar form from this horizon with which to compare
FOSSILS OF THE CAMBRIAN. 23
this shell, its small size, bilobed dorsal valve, and subcarinate ventral valve distinguishing it from all other described species.
Formation and locality—Cambrian. Prospect Mountain Group, at the base of the Secret Canon shale, on the west side of Secret Cation, Eureka District, Nevada.
PTEROPODA. Genus STENOTHECA Salter.
Stenotheca elongata, n. sp. Plate ix, figs. 2, 2a.
Shell small, elongate, with the apex incurved and depressed nearly to the margin; laterally compressed so as to form a ridge nearly the entire length. Aperture elongate, ovate, somewhat acutely pointed at the end towards which the apex curves and rounded at the opposite extremity, the greatest width occurring about two-thirds the distance from the narrow end. Surface marked by numerous fine concentric strie and lines of growth.
The narrow elongate aperture, depressed apex, and fine lines of growth serve to distinguish this from described species of the genus. As far as yet known the genus Stenotheca is confined to the Cambrian fauna.
Formation and locality—Cambrian. Prospect Mountain Group, in the limestone just beneath the Secret Canon shale, on the west side of Secret Cafion, Eureka District, Nevada.
Genus HYOLITHES Eichwald. Hyolithes primordialis Hall (Sp.)
Theca primordialis Hall, 1861. Rep. Prog. Geol. Surv. Wisconsin (pam.), p. 48. Ibid., Geol. Wis., vol. i, p. 21, fig. 5, 1862. Ibid., Sixteenth Rep. N. Y. State Cab. Nat. Hist., p. 135, pl. vi, figs. 30, 31, 1863.
Hyolithes (Theea) primordialis Hall and Whitfield, 1873. Twenty-third Rep. N. Y. State Cab. Nat. Hist., p. 242, pl. ii, fig. 3.
Hyolithes primordialis? White, 1874. Expl. and Surv. West 100th Merid., Prelim. Rep. Invert. Foss., p. 6. Ibid., vol. iv, pt. 1, p. 37, pl. 1, figs. ee 1875.
Hyolithes primordialis Whitfield, 1883. Geol. Wisconsin, vol. = p. 175, pl. 1, fig. 12.
24 PALEONTOLOGY OF THE EUREKA DISTRICT.
There appears to be very little difference between the Eureka speci- mens and those described by Professor Hall from the Potsdam sandstone of Wisconsin. Dr. C. A. White describes similar forms from Pioche, Nevada, where they occur in strata of (“Primordial”) Cambrian age. |
Formation and localities —Cambrian. Prospect Mountain Group, in the upper beds of the Secret Canon shale, on the east side of New York and Secret Canons, and on the east side of the canon at the eastern side of Ruby Hill. Also in an outcrop of limestone on the west side of the foot- hills of Combs’ Peak, Antelope Valley, Eureka District, Nevada.
PCECILOPODA.
Genus AGNOSTUS Brongniart.
Agnostus Richmondensis, n. sp. Plate ix, fig. 10.
Cephalic shield moderately convex, length and breadth equal, sides scarcely parallel, rounding in front into the broadly rounded anterior margin. Glabella three-fourths the length and a little more than one-third as wide at the base as the width of the shield, it is elongate-conical in out- line, strongly defined by the dorsal furrows, and with the anterior third separated by a distinct transverse furrow, a little less than midway between this furrow and the posterior margin a short furrow penetrates from each side towards the base of a minute tubercle situated on the median line, two oblique furrows cut off the posterior lateral angles as two small rounded, triangular nodes; lateral lobes more convex than the glabella, divided anteriorly by a slight median furrow, surrounded by a narrow, rim-like margin, and ornamented by slightly irregular depressed lines that indent the surface from the margin nearly to the edge of the strong dorsal furrows.
Surface smooth under an ordinary magnifying power.
Dimensions.—Length and breadth, 2.5"; depth of shield, 0.75™™. Tho-
racic segments and caudal shield unknown.
FOSSILS OF THE CAMBRIAN. 25
This is a very striking and pretty species, and is not liable to be mis- taken for any described American form, and it appears to be distinct from any European species known to me, although allied in a slight degree to Agnostus princeps Salter.
Formation and localities—Cambrian. Prospect Mountain limestone, upper portion; Ruby Hill, Richmond mine, 700-foot level; and east slope of the northern portion of Prospect Mountain, Eureka District, Nevada.
Agnostus seclusus, n. sp.
Plate ix, fig. 14.
Cephalic shield strongly convex, a little longer than wide, with a slight contraction posteriorly and margined by a narrow, rim-like border that has a distinct groove between it and the lateral lobes; dorsal furrows well defined, united anteriorly, but not dividing the lateral lobes in front, pos- teriorly each turns obliquely outward, a short distance from the margin, cutting off the inner angle of the lateral lobes Glabella short about one- half the length of the shield, strongly convex and squarely truncated in front; at about the anterior third a broad, short furrow penetrates on each side a short distance, and posteriorly a rounded node is separated from each lateral angle by slight furrows; the lateral lobes slope rapidly to the marginal groove on the sides and more gradually to the front.
Surface finely granulose.
Dimensions.—Length, 3""; breadth, nearly the same; depth of shield, 1.257.
Thoracic segments and caudal shield unknown.
This species is characterized by the tumid, short, truncated glabella and broad lateral lobes.
Formation and locality—Cambrian. Prospect Mountain Group; upper portion Secret Cafion shale, on the east side of Secret Cafion, Eureka Dis- trict, Nevada. ,
26 PALEONTOLOGY OF THE EUREKA DISTRIOT.
Agnostus bidens Meek. Plate ix, figs. 13, 13 4.
Agnostus bidens Meek, 1873. Sixth Ann. Rep. U.S. Geol. Surv. Territories for the year 1872, p. 463.
Cephalic shield, moderately convex; a little wider than long, distinctly trilobed and bordered by a rounded margin, with a rather strongly defined marginal groove. Glabella convex, narrow, more than two-thirds the length of the shield, converging anteriorly and rounded or subangular in front; a narrow, transverse furrow enters obliquely from each side poste- rior to the center and unites just in advance of a small tubercle on the center of a segment defined behind by a transverse furrow that bends back- ward at the center; between the latter furrow and the occipital furrow, a nurow segment widening out laterally, is distinctly defined; occipital seg- ment very narrow. Dorsal furrows distinct, united in front of the glabella but not touching the frontal border. Lateral lobes strongly convex and sloping rapidly to the marginal groove from the somewhat elevated central portion; frontal lobe about half as wide as the lateral lobes and less convex.
Thoracic segments unknown.
The caudal shield associated with the above-described head has all of its essential elements, and there is little doubt but that it belongs to the same species. It is provided with a short spine or process on each posterior lateral side and is strongly convex and trilobate; the axial lobe extends more than three-fourths of the entire length and has an elongate, angular node on the anterior portion, with a transverse furrow just before it separat- ing a narrow anterior portion, and in some examples a slight transverse furrow crosses just back of the node; this is obsolete in many instances. The dorsal furrows extend backward and unite posteriorly, giving the axial lobe a conical form; lateral lobes strongly convex and very much like those of the associated cephalic shield. Surface of both shields finely granulose under a strong magnifying power.
FOSSILS OF THE CAMBRIAN. 27
Dimensions of cephalic shield—Length, 3.25™"; width, 3.75""; caudal shield as 4 is to 5 in length and breadth respectively.
A comparison of specimens made after the manuscript of this report was written shows that the supposed new species of Agnostus is identical with Mr. Meek’s A. bidens from the Gallatin River, Montana, also that Ptychoparia Gallatinensis occurs in association with it in Montana and Nevada.
Formation and localities.—Cambrian. Prospect Mountain Group ; ranges from the upper portion of the massive Prospect Mountain lime- stone as found in the 700-foot level of the Richmond mine at Ruby Hill and on the east slope of Prospect Mountain, to the summit of the Ham- burg limestone, near the Hamburg mine, and into the base of the Po- gonip Group, occurring most abundantly in the upper beds of the Secret Canon shale, Eureka District, Nevada. Also in the Lower Pogonip Group on Pogonip Ridge, White Pine District, Nevada.
Agnostus communis H. & W. Agnostus communis Hall & Whitfield, 1877. Geol. Expl. Fortieth Parallel, vol. iv, p. 228, pl. i, figs. 28 and 29.
This species has a vertical range similar to the preceding, and occurs at: the same localities, although rarely in the same layer of rock. The orig- inal specimens were collected by the geologists of the Fortieth Parallel Survey from the White Pine Mining District, Nevada.
Agnostus Neon H. & W.
Agnostus Neon Hail & Whitfield, 1877. Geol. Expl. Fortieth Parallel, vol. iv, p. 229, pl. i, figs. 26, 27. Associated with Agnostus communis, and having essentially the same range and distribution in the district, the original types coming from the Kureka District, Nevada, by the same survey.
28 PALEONTOLOGY OF THE EUREKA DISTRICT.
Agnostus prolongus H. & W. Agnostus prolongus Hall & Whitfield, 1877. Geol. Exp]. Fortieth Parallel, vol. iv, p. 230, pl. i, figs. 30, 31.
This form was originally collected in the Eureka District, but it is rare, having been found only in the Hamburg belt of limestone northeast of Adams Hill, and on the west side of Sierra Cation, Eureka District, Ne- vada.
Genus OLENELLUS Hall. Olenellus Iddingsi, n. sp. Plate ix, fig. 12.
General outline of the head roughly subtriangular, with the length one-half the breadth of the posterior border; strongly convex; the rather narrow, rounded rim bordering the anterior margin suddenly becomes thickened and rounded opposite the eyes and is extended back in the short, strong, slightly curved genal spines, the narrow posterior marginal border uniting with it at the genal angles. Glabella elongate, narrow, divided by four transverse furrows into five lobes; the anterior is round, tumid, and ex- panded laterally, while the four posterior are narrow, transverse, of equal size, and with their sides parallel; occipital ring and furrow not recog- nized; eyes lunate, 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, cutting the posterior margin about two- thirds the distance from the glabella to the postero-lateral spine.
Thorax and pygidium unknown.
The specific name is given in honor of Mr. J. P. Iddings, the discov- erer of the type specimen.
Formation and locality—Cambrian. Prospect Mountain Group, in an arenaceous shale above the quartzite capping Prospect Peak, Eureka Dis- trict, Nevada.
FOSSILS OF THE CAMBRIAN. 29
Olenellus Gilberti Meek. Plate ix, fig. 16, 16a; pl. xxi, fig. 13.
Olenellus Gilberti Meek, 1874. (Manuscript.) Olenellus Gilberti White, 1874. Geog. and Geol. Expl. and Surv. West 100th Merid.; Prelim. Rep. Invert. Foss., 7. Olenus (Olenellus) Gilberti Meek, 1875. Geog. and Geol. Surv. West 100th Merid., vol. ili, Geology, p. 182. Olenellus Gilberti White, 1875. Geog. and Geol. Expl. and Surv. West 100th Merid., vol. iv, pt. i, p. 44, pl. li, figs. 3 a, e. Head semioval in outline, moderately convex, margined all around by _a narrow wire-like rim, which is produced at the genal angles into slender spines Glabella elongate, narrowing slightly towards the front; general surface moderately convex anteriorly, becoming less so back of the frontal lobe; the glabellar furrows penetrate obliquely backward nearly to the median line, with the exception of the second anterior pair, which are shown by elongate depressions on the line of division of the second and third anterior lobes, the two lobes uniting laterally so that the furrows do not extend to the dorsal furrows; the frontal glabellar lobe is convex, oval in outline, with a tendency in some examples to become angular in front; the two posterior lobes are subequal in size; the occipital ring and furrow well defined; eyes elongate, narrow, arching outward from the point where the anterior glabellar furrow meets the dorsal furrow, and backward to the posterior glabellar furrow; dorsal furrows shallow; the fixed and free cheeks united form a broad slope from the eye to the lateral margins and anteriorly merge into the long frontal limb. The facial sutures cannot be traced in any of the specimens. Thorax and pygidium unknown. | The above description is drawn from specimens obtained in the Eureka District. The differences between them and the type specimens are almost entirely in the frontal limb, the former having a much broader space between the front of the glabella and marginal rim. In some examples from the typical locality of the species at Pioche, Nevada, the frontal limb is much broader than in those illustrated in Dr. White’s report, the Eureka form appearing to be specifically identical with them. Formation and. locality—Cambrian. Prospect Mountain Group, in an arenaceous shale above the quartzite capping Prospect Peak, Eureka Dis- trict, Nevada.
30 PALEONTOLOGY OF THE EUREKA DISTRICT.
Olenellus Howelli Meek.
Plate ix, figs. 15, 15a, 6, and pl. xxi, figs. 1, 9.
Olenellus Howelli Meek, 1874. (Manuscript.)
Olenellus Howelli White, 1874. Geog. and Geol. Exp]. and Surv. West 100th Merid. ; Prelim. Rep. Invert. Foss., p. 8.
Olenus (Olenellus) Howelli Meek, 1875. Geog. and Geol. Surv. West 100th Merid., vol. iii, Geology, p. 183.
Olenellus Howelli White, 1875. Geog. and Geol. Expl. and Surv. West 100th Merid., vol. iv, pt. 1, p. 47, pl. ii, figs. 4a, b.
The general outline of the head of the adult is semi-elliptical or semi- circular and more or less strongly convex. The margin is bordered by a narrow, rounded rim which becomes thickened near the genal angles and continues posteriorly as rather short, sharp spines. The glabella is elon- gate and more or less expanded in front and behind, contracting a little midway; four pairs of glabellar furrows penetrate from each side; they are somewhat strongly impressed on each lateral third of the width of the gla- bella, becoming more shallow as they pass into the more shallow furrow that unites them across the center; in younger specimens this furrow is undis- tinguishable from the lateral furrows and they all unite as one distinct fur- row crossing the glabella trom side to side, and even in the adults this fea- ture is strongly marked in some individuals; the anterior lobe of the gla- bella is more or less tumid, subhemispherical or a little transverse and wider than the greatest width of the glabella immediately behind it; the next pos- terior lobe is rather narrow and transverse, differing from the two next pos- terior lobes, which are wider and curved a little forward at the ends, by the direction of the furrows; the posterior lobe corresponding to the occipital ring or segment is broad and essentially of the same character as that pre- ceding it; the furrow separating them is very shallow at the center and in- clined obliquely backward at the sides; asmall node occurs on one example at the center of the occipital ring. -
Eyes elongate, narrow, and arching from opposite the anterior glabellar lobe to opposite the occipital furrow. The dorsal furrows are narrow, dis- tinctly but not deeply impressed. Fixed cheeks a little expanded anteriorly and scarcely more than a line between the elongate palpebral lobes and the dorsal furrows, while posteriorly they merge into the small triangular late- ral limbs; frontal limb obsolete. Free cheeks large, roughly subtriangular
FOSSILS OF THE CAMBRIAN. 31
in outline, their posterior margin marked by a more or less prominent curve or angle between the genal angle and the inner end of the margin.
The facial suture cuts the anterior margin some distance outside the line of the outer margin of the glabélla and passes obliquely inward to the anterior angle of the eyelobe; curving around the outer margin of this, it passes obliquely outward to the posterior margin, cutting it about midway between the glabellar lobe and the outer margin of the genal angle.
The surface of the glabella is beautifully ornamented with transverse, fine, irregularly-waving, subimbricating lines that give the appearance of imbricating lamelle resting one under the other from before backward; this feature is only seen on the most perfectly preserved specimens; the surface of the cheeks is slightly granulose under a strong magnifying glass. The test itself is very thin and fragile and is usually broken away.
Thorax and pygidium unknown. Portions of the pleural lobe of sev- eral thoracic segments were found in association with the heads of this and the preceding species that show that the pleuron is prolonged in all of them, in one more than the others, and that the portions of the segments preserved are typical in their character of the genus; the pleural groove is strong and broad, continuing well out towards the extremity beyond the geniculation.
The description of the cephalic shield is that of what is considered as the normal, adult type of the head, and omits altogether the phases of this remarkable species that are shown in its various stages of growth and devel- opment. <A note and several figures in illustration are appended that were prepared after the first study of the collections.
The above description was written in 1880 under the impression that the species was undescribed. On obtaining a large number of specimens in 1882, it was found that the species could be connected with Olenellus Howelli, a species founded by Mr. Meek on a single large head from the Cambrian at Pioche, Nevada. Ona direct comparison with the type the larger specimens are seen to be essentially the same if we allow for the compression of the Eureka specimens in the sandy shale.
Formation and locality—Cambrian. Prospect Mountain Group in an arenaceous shale above the quartzite capping the summit of Prospect Peak, Eureka District, Nevada.
32 PALEONTOLOGY OF THE EUREKA DISTRICT.
OBSERVATIONS ON OLENELLUS HOWELLI.
Plate xxi, figs. 1-17.
The study of the material in the collection illustrating this species hay- ing developed some interesting facts, they are here discussed under two heads: First, the character of the species during the later stages of its development as far as known; second, the relation of the species to other species of the same genus, and to certain species of the genus Paradoxides.
I. A series of specimens illustrating the principal embryonic and abnor- mal features of development are figured on plate xxi, figs. 1-9, the details of which, and also the figures up to fig. 18, are given in the explanation accompanying the plate.
Contour of the head—The smallest specimen of the head observed, tig. 1, is 2.5"" in length, and resembles in its outline the larger head, fig. 3, which has a length of 7.5™", as is seen more clearly by comparing the latter with the enlarged figure of fig. 1, on plate ix, fig. 150. Between figs. 1 and 3, in size, is the form represented by fig. 2, which is transversely quadri- lateral 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 and the geniculation of the posterior margin, which is so strongly marked in fig: 1, is still further increased to form an angle of nearly 90°, which, from its position, might be incorrectly viewed as the true genal angle if the anterior spines were broken away or obscured and the course of development of the species unknown. In fig. 4 the genal spines are still more anterior than in the smaller forms (figs. 1 and 3), presenting a transition stage, not consider- ing the size of the head, but the general form, between figs. 1 and 2 or 2 and 3, the angles of the posterior margin 22, are also more obtuse and the frontal margin broadly rounded. Through the forms represented by figs. 3 to 5 the modification of these features is very uniform to the normal adult type of the contour of the head, as shown by fig.6. In figs. 7 and 8, how- ever, which are considerably larger specimens, the angularity of the pos- terior margin is a prominent feature, the genal angles being advanced as in the forms before fig. 6. In fig. 9 the outline is still further diversified by having the angularity of the posterior margin and the position of the genal
FOSSILS OF THE CAMBRIAN, 33
spine on one side differing from that on the other. Fig. 6 is considered as nearly typical of the adult outline of the head as the largest specimen found, and a number of medium size have the same form. The genicula- tion of the posterior margin is an embryonic character that is singularly persistent in many examples of otherwise adult character. In figs. 12, 13, and 14 the adult form of the head of three other species of the genus is shown.
Glabella—There is not as decided a change proportionally between the glabella of the smallest individual and that of the normal adult as there is in the outer contour of the head; still it is to be observed, that the dorsal furrows are not continuous but interrupted by the ocular ridges that cross them and unite with the frontal lobe of the glabella (figs. 2, 4, and 6), a feat- ure unknown in the adult, that in the younger individuals the glabellar furrows extend entirely across the glabella, while in the older ones they are more or less interrupted or united only by very shallow transverse furrows at the center.
Eyes.—The usual form of the eye of the adult in this genus is shown in figs. 7, 8, 9, 12, and 14, where it is narrow, broadly arching outward, and _ with a more or less narrow palpebral lobe close to the glabella. In tracing the development of the eye of Olenellus Howelli, it is found, in the earliest stage with which we are acquainted, to be situated distant from the glabella toward the center of the cheek and united to the anterior lobe of the gla- bella by a strong ocular ridge that crosses and interrupts the continuity of the dorsal furrow (see fig. 2 and enlargement of fig. 1 on plate ix, fig. 15b). There is considerable variation in the relative position of the eye and the length and strength of the ocular ridge in different examples of the head. In fig. 2 the ocular ridge of the left side is elevated, and with the high margin of the eyelobe partially incloses the depressed area within, while on the right side of the same individual both the ridge and eye are less elevated, and the ocular ridge being shorter the eye is brought in nearer to the glabella. In fig. 4 the ocular ridge is narrower at the point of union with the glabella and attached farther back near the posterior margin of the frontal lobe. Frequently the longitudinal axis of the eye is
slightly oblique from its anterior end backward and outward. With the 3 CDW
34 PALEONTOLOGY OF THE EUREKA DISTRICT.
increase in size, these features usually disappear, although in fig. 6 there is an exception, as they are retained in a modified degree after other accom- panying embryonic features of the head have disappeared. Between the eye and glabella, when the former is situated well out on the cheek, a small round or oval boss occurs, as shown in figs. 2, 3, 4, and 6.
Facial suture-—The course of the facial suture in front of the adult head is shown by the free cheek, fig. 17(s). Of its variation from this course during the development of the individual nothing is known from actual observation, but from the fact that the relative position of the eye changes, it is probable almost to a certainty, that its direction is somewhat varied, and we know that such is the case in its direction back of the eye when the latter is situated out on the cheek or near the glabella. Back of the eye, in all the instances in which it has been observed, its direction is slightly outward, with a sigmoidal curvature to the angle of the posterior margin, or, in its absence, at the broad curve denoting the position of the angle about midway between the dorsal furrow and the genal angle, figs. 3, 4, 5, and 6. In the large adult specimens its course was probably as indicated by the traced line in fig. 9, where it is much the same as in the genus Ogygia or Dicellocephalus, and even more so in the cheek, fig. 17, if it cut the poste- rior margin at the angle 2, as it does in all known cases in the smaller speci- mens, figs. 3, 4,5, and6. Comparing this with the direction of the stages of growth shown in figs. 3 and 4, where another generic group is suggested by its Paradoxides-like course, the contrast is very striking.
In the adult specimens of Olenellus Gilberti and O. Vermontana the course of the facial suture is almost directly backward from the eye to the margin, corresponding nearly to the line o 0, of fig. 17, and terminating far within the angle w That the course of the suture was the same in the larger heads of O. Howelli is not probable, as the head, fig. 6, shows it ter- minating at the place of the angle «. But the fact that in the closely allied species O. Gilberti the termination is between the angle and the dorsal suture would lead to looking for it there in O. Howelli; that its course, if not con- stant in the large adults, is as in fig. 6} only adds another anomalous feature to this strange species.
Mode of development—The normal development of a trilobite from the
~
FOSSILS OF THE CAMBRIAN. 35
earliest embryonic condition with which we are acquainted to the adult form is marked by the disappearance of the embryonic characters one by one as the individual increases in size and assumes more and more the feat- ures of the fully developed animal, all of which usually takes place, except in size and surface ornamentations, when it is quite small. The retaining of an embryonic feature after the individual has passed in size, or any other character, the stage at which it usually disappears in the regular course of the development of the species, is an exceedingly rare occurrence, and is unknown, to our own knowledge, except in the increase in size of the body in certain species, so that in their 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 consequently more advanced in development. M. Barrande has shown this to be the case in the development of Arethusina Konincki, Proetus decorus, and P. venustus,t and we have observed it in Triarthrus Becki, where the relative size, proportional to the development, is very marked, e. g., an individual with 13 segments in the thorax is 24™™ in length, and one with 16 segments but 16.5"" long, while the fully-grown example of 16 segments reaches a length of 53™", and some with 13 seg- ments are but 7"™ in length.’
This peculiarity of growth is shown in the species mentioned only by the thorax, for if we take the head apart from it there is little or nothing to prove that its size is not proportional to the stage of development; but in Olenellus Howelli the head proves this to be otherwise, and there may be added to the statement, that in certain species the size is not proportional to the num- ber of liberated segments in the thorax, that in other species the size of the head is not always proportional to its stage of development. It is greatly to be regretted that the thorax and pygidium are not preserved, so that a direct comparison of those parts could be made with abnormal conditions of development in other genera and species.
Having shown that the peculiar development of this species, exhibited in the acceleration and retardation of growth in individuals as compared with each other, is in a measure comparable with the peculiarities of growth
‘Systéme Silurien de la Bohéme, vol. i, p. 268, 1852. >Trans. Albany Inst., vol. x. Fossils of the Utica Slate, p. 29, 1879.
36 PALEONTOLOGY OF THE EUREKA DISTRICT.
in some other species, a few of the questions arising from the study of the stages of growth observed will be spoken of as they are shown in the first nine figures on plate xxi.
It is impossible to imagine that the course of development was by size through figs. 1, 2, 3, 4, and 5; but if we take out the two forms figs. 2 and 4, those remaining, figs. 1, 3, 5, and 6, constitute a very good advancing series and the larger specimens, figs. 7, 8, 9, might be considered as illus- trating the principle that the size is not proportional to the stage of develop- ment. The two forms taken out, figs. 2 and 4, however, prevent the first, if we consider them as belonging to the same species, as appears to be the case. They are associated with such forms as 3, 5, &c., and the two species Olenellus Gilberti, plate ix, fig 16, plate xxi, fig. 13, and O. Iddingsi, plate ix, fig. 12, in the same hard specimens of arenaceous shale, and, although fig. 2 is an extreme form, fig. 4 is a gradation in form to such forms as figs. 1 and 3. It is observed that figs. 7, 8, and 9 precede 6 in the stage of devel- opment of the contour of the head, at the same time showing a more accel- erated development in the form of the eye. The eye of fig. 5 is more ad- vanced than that of fig. 6, while the posterior outline of the head is more embryonic in its character. With these examples it is readily conceived that figs. 2 and 4 are enlarged examples of the forms that preceded fig. 1 in development, and the eye of fig. 2 supports this view, as it is, in its strongly developed ocular ridge, which is more marked than in fig. 1, and more an- terior in relation to thetrontal lobe of the glabella, essentially more embryonic; and the position of the genal angles and spines is either a decided embryonic feature, or a sport that, with fig..4, to connect it with figs. 1 or 3, would not be considered as probable.
Was, then, the probable course of development of this species, before it reached the character of fig. 1, through earlier stages to a form like fig. 2, thence to figs. 4, 1, 2, 5, and so on to the adult?
In the development of Olenellus asaphoides, as given by Mr. Ford,’ the youngest stage is about 2™" in diameter and nearly circular in outline, the genal angles and spines are situated close in by the side of the facial suture, as it is subsequently developed, and there appears to be no doubt but that
’Amer. Journ. Sci., 3rd ser., vol. xiii, p. 265, figs. 1-4, 1877. Ibid., vol. xxii, p. 250, 1881.
FOSSILS OF THE CAMBRIAN. 37
it is embryonic and representative of one of the earlier stages of growth of the species. The second stage, of which an outline figure is given on plate xxi, fig. 10, has changed somewhat, but the essential elements re- main, and in fig. 11 there is a still greater expansion of the posterior margin of the head and the genal angles are carried slightly forward. There are probably several intermediate forms between figs. 10 and 11 that have not as yet been discovered, but for the present comparison they may be dis- pensed with, as in fig. li we have a form that may be compared in the contour of the head with our figs. 1 and 3; the genal angles are forward of the line of the posterior margin, and strong obtuse angles occur where the facial sutures cut the latter at wx. In fig. 12 the normal adult form of the head of this species is outlined. Reviewing the development thus hastily sketched, it is seen that the form fig. 11 is intermediate between figs. 10 and 12, and representative of the group of forms found in O. Howelli, be- tween fig. 6 and the earlier forms preceding fig. 1 in size, fig. 6 being considered as nearest the adult type in the contour of the head. Without more data, it is, perhaps, conjectural to consider that the forms preceding fig. 1 were like figs. 2 and 4, and that preceding these the earlier stages of O. asaphoides were represented, the forms figs. 2, 4, 1, 8, 5 occupying the position in development taken by 11 in the latter species. At present no other view seems as reasonable, unless it is thought that fig. 2 represents the extreme embryonic tendency of the species, a course of development the reverse of that of Olenellus asaphoides, or any known species of the tri- lobita, and one not at all probable in this instance.
Il. Relations to other species and genera.—The difficulty met with in comparing the abnormal development of this species with that of other species in which the thorax and pygidium are known is also felt in study- ing its relations to various species and genera in which the structure of the entire body is known, restricting as it does all comparisons to the head.
The species associated with Olenellus Howelli are O. Gilberti, plate ix, fig. 16, plate xxi, fig. 13, and O. Iddingsi, plate ix, fig. 12. The smallest head of the former, fig. 13, is about the size of fig. 2 of the same plate, but does not present the strong embryonic features of the latter. In compari- son with the adult head of the same species, plate ix, fig. 16, it is observed
358 PALEONTOLOGY OF THE EUREKA DISTRICT.
that the eyes in the smaller individual are a little distant from the glabella and united to it by a very short ocular ridge; otherwise no embryonic features are indicated. The example of the head of O. Iddingsi is still smaller, but it does not present any recognized embryonic features.
Olenellus Gilberti and O. Howelli also occur at the same relative geologic horizon, at Pioche, Nevada, 130 miles (209.2 kilometers) distant. The for- mer species in that locality is noticeable in having, in the smaller specimens observed, an obtuse angle in the posterior margin of the head midway between the genal angle and the glabella (see outline, fig. 14, plate xxi). In the larger specimens the angle is near the outer portion of the margin or a little within the postero-lateral angle. The facial suture back of the eye is quite unlike that of O. Howelli, as shown for the latter in figs. 5 and 6, and cuts the posterior margin between the angle, 2 x, of the margin and the glabella, as seen in figs. 14 and 17. In comparing with O. Thompsoni and O Vermontana Hall, from the Georgia slates of Vermont, it is only to be observed that in the former species the general features of the adult, as far as known, appear to be the same, and that in the latter the facial suture has the same course back of the eye as in O. Gilberti, and Prof. R. P. Whitfield has shown me a‘ specimen in the collection of the American Museum of Natural History that is marked by a very short spine on the obtuse, rounded angle of the posterior margin, a short distance within the postero-lateral angle, a character not observed in any other species of the genus.
Mention has been made of Olenellus asaphoides and certain resemblances in the contour of its head at the stage of development represented by fig. 11, and that of the head of O. Howelli as seen in figs. 1, 3, 5, ete. The curious interocular spines of the former have not been seen in O. Howelli. Mr. Ford has called attention to the Paradoxides-like run of the posterior margin of the head, g a, wg, fig. 11, and states that it disappears altogether during the embryonic life of that species. We have shown that it is extravagantly developed in O. Howelli, even to the extent of changing the entire contour of the head, fig. 2, and that it persists in the adult stage of many individuals of this species, and is also present in O.. Gilberti and O. Vermontana.
In all the observed specimens of O. Howelli showing the facial suture back of the eye the posterior margin is cut by it at the angle within the
©
FOSSILS OF THE CAMBRIAN. 9
iv)
postero-lateral angle, as Mr. Ford has pointed out for the form, fig. 11, of O. asaphoides, and also in the genus Paradoxides.
Attention is again called to the direction of the facial suture back of the eyes, in figs. 3 and 4, and the position and obliquity of the eyes in re- lation to the median line of the glabella, characters of Paradowides, as seen in P. spinosus. Of all the species of the latter genus, P. Kjeruifi* alone shows the presence of an ocular ridge uniting the eye and the frontal lobe of the glabella, fig. 15 (a), a feature so prominent in the young of O. Howelli, as well as the small, rounded protuberance between the eye and the glabella, shown in Linnarsson’s fig. 2, of P. Kjerulfi. The latter character Mr. Ford discovered in the young of O. asaphoides, and noted its resemblance to the same in P. Kjerulfi. The ocular ridge, a feature in the latter that is per- manent, is also present in the young of O. Howelli, but disappears in the adult, adding in this another link to the argument so admirably brought forward by Mr. Ford to show the genetic relation of the two genera.
Résumé.—The study of the head of Olenellus Howelli proves:
First. That in certain individuals of this species the existence of em- bryonic features continues long after the individual has reached the size at which such features are usually lost in the process of development of other species of the genus.
Second. That in individuals otherwise developed equally in all respects some one of them may have a characteristic feature, such as the eye or the genal angle, developed to a greater or less degree than in the others, and that this feature may persist even after the individual having it has passed in size or other characters the stage at which it is usually lost
Third. That the development of certain characters went on in an unequal degree in the corresponding parts of the same individual, and, finally, that certain features present in the younger individuals and disappearing during the subsequent growth are permanent features in some species of the genus Paradoxides.
4Ofversigt af Kongl. Vetenskaps-Akademiens Férhandlingar, N:o. 6, Stockholm, p. 790, Tafl. xvi, figs. 1, 2. 1871.
40 PALEONTOLOGY OF THE EUREKA DISTRICT.
Genus DICELLOCEPHALUS Owen. Dicellocephalus bilobatus H. & W.
Dicellocephalus bilobatus Hall & Whitfield, 1877. Geol. Expl. Fortieth Parallel, vol. iv, p. 226, pl. 2, fig. 36.
This species was founded on a pygidium having a bilobed posterior border, collected in the Eureka District by the geologists of the Fortieth Parallel Geological Survey. The same character of pygidium was obtained by the present survey in the upper beds of the Cambrian, on the east side of the Sierra Valley, east of Pinnacle Peak, Eureka District, Nevada.
Dicellocephalus Osceola Hall. Plate ix, fig. 25. Dikelocephalus osceola Hall, 1863. Sixteenth Ann. Rep. N. Y. State Cab. Nat. Hist., p. 146, pl. x, fig. 18; pl. vil, fig. 49?
Original type from the Potsdam sandstones at Osceola Mills, State of Wisconsin.
A comparison of the Nevada specimens, consisting of the glabella and fixed cheeks, with the type example of the species in the American Museum collection, shows such a strong specific identity of the parts preserved that there is little doubt, with our present information, but that they belong to one and the same species.
Formation and locality—Cambrian. Prospect Mountain Group, upper portion, on ridge north of the Dunderberg mine, Eureka District, Nevada.
Dicellocephalus nasutus, n. sp. Plate x, fig. 15.
Glabella and fixed cheeks, when united, subquadrangular in form, the width being about three-fourths of the length. The glabella is broadly conical, rounded in front, and with its convex surface marked by two slightly impressed pairs of anterior furrows, and a pair of more strongly
marked posterior furrows that penetrate obliquely inward to a shallow
FOSSILS OF THE CAMBRIAN. 4}
transverse furrow that unites them; occipital ring of medium width and separated from the glabella by a well-defined, but not deeply impressed occipital furrow; dorsal furrows of medium strength on the sides of the glabella but scarcely shown in front; fixed cheeks unusually narrow and rising directly up to the large, elongate palpebral lobes; anteriorly they slope into the groove of the frontal limb; posterior extension and postero- lateral limbs unknown; frontal limb between the glabella and furrow nearly obsolete, extending beyond the furrow as a broad subspatulate, somewhat convex margin. ‘The facial suture curves a little outward in front of the eye as far as the furrow of the frontal limb and then recurves inward around to the front; after curving around the large eyelobe to near the posterior margin, its further course has not been traced.
Surface smooth or slightly punctate.
Thorax and pygidium unknown.
Formation and localities —Cambrian. Prospect Mountain Group, central portion Secret Canon shale in New York Canon, and upper layers of same on north side’ of the cafton opposite the dump of the shaft of the Richmond mine, Ruby Hill, Eureka District, Nevada.
Dicellocephalus Richmondensis, n, sp.
Plate x, fig. 7.
Glabella and fixed cheeks, united, quadrangular in form, the width being a little greater than the length. Glabella elongate-subquadrangular, lateral margins slightly converging anteriorly, and with the front a little rounded; length and breadth as three to four; surface moderately convex, and marked by a slightly impressed ‘posterior pair of furrows, directed obliquely inward two-thirds the distance to the median line, and two pairs anterior to these that are just discernible upon the smooth surface; occip- ital ring of medium width, distinct; occipital furrow distinct, but not deeply impressed; dorsal furrows well defined at the sides but only a line in front of the glabetia; fixed cheeks broad, rising slightly from the dorsal furrows to the palpebral lobes and sloping away before and behind quite rapidly; frontal limb rather long and wide, the marginal rim broadly arcuate, the-
42 PALEONTOLOGY OF THE EUREKA DISTRICT.
width more than one-half the length of the limb between it and the glabella, somewhat flattened and with a narrow groove between it and the depressed limb; posterior lateral limbs narrow, marked by the extension of the occip- ital furrow within their posterior margin. The facial sutures cut the frontal rim obliquely, and recurving inward pass to the palpebral lobes; curving around these opposite the central portion of the glabella, they then extend obliquely outward and backward, cutting the posterior margin beyond a line with the eyelobes.
Surface smooth to the unaided eye; minutely punctate under a strong magnifying power.
This species is distinguished by its broad fixed cheeks and long frontal margin with the flattened rim.
Formation and locality—Cambrian. Prospect Mountain Group, upper beds of the Secret Canon shale, on the opposite side of the cafion from the dump of the shaft of the Richmond mine, Ruby Hill, Eureka District, Nevada.
Dicellocephalus ? angustifrons, n. sp.
Plate x, figs. 1, lab.
Glabella subquadrate; width at the base equal to the length, but nearly one-third greater than the width of the anterior margin; surface moderately convex, curving down in front and marked by two pairs of lightly impressed glabellar furrows that extend obliquely inward one-third the distance across the glabella, the posterior pair nearly separating the posterior triangular lobes; occipital ring rather broad and distinctly defined by a strong occip- ital furrow; dorsal furrows narrow but strongly impressed; fixed cheeks very narrow and hardly separable from the palpebral lobes, which are large, elongate, and situated opposite the central portion of the glabella; frontal limb merely a line between the glabella and the rounded rim; lateral limbs only partly known; they appear to be narrow and rather short.
Associated with the glabella and fixed cheeks are numerous free cheeks ~ that undoubtedly belong to this species. They are triangular with the upper angle truncated to form the base of the eyelobe; the outer margin is strong, somewhat flattened, and separated from the rapidly ascending slope to the furrow at the base of the eye by a sharp narrow groove. The
FOSSILS OF THE CAMBRIAN. 43
union of the free cheeks with the fixed cheeks would give the head a semicir- cular, strongly convex form, with rounded postero-lateral angles. The pygidium occurring with the other parts is transversely elliptical, about one-third wider than long, and elevated on the median lobe; the frontal margin is broadly rounded, the lateral margins scarcely angular at the union of the frontal margin and the more sharply rounded posterior line; axial lobe elevated, convex, about one-half the length of the pygidium, and marked by six transverse rings, including the terminal one; lateral lobes broad, sloping rapidly away from the axial lobe and then spreading out in a broad, flattened border; their surface is marked by three broad anchy- losed segments, besides the narrow anterior articulating projection and the broad posterior termination.
Surface of the head finely granulose, and the pygidium the same, with the exception of the irregular strize on the border, the latter are sub- parallel to the margin.
This species in the general form of the head and pygidium resembles many species referred by Mr. Billings to his genus Bathyurus, but it is nearer Dicellocephalus, if we compare it with typical forms of the genus from the Potsdam sandstone of Wisconsin, and is referred to that genus provisionally. .
Formation and localities.—Cambrian. Prospect Mountain Group. Summit of Hamburg shale, on the ridge north of the Dunderberg mine, and ina matrix of a similar character at the southeast base of Lookout Mountain, Sierra Caton, Eureka District, Nevada.
Dicellocephalus Tole, n. sp.
Plate x, fig. 19.
Glabella subquadrate, length exclusive of the occipital ring equal to the width at the base; it narrows a trifle anteriorly, is transverse in front, and has its laterai angles rounded; surface gently convex, rounding down- ward in front, and marked by twapairs of rather strong, but not deeply impressed, furrows that extend obliquely inward well towards the median line.
44 PALEONTOLOGY OF THE EUREKA DISTRICT.
Occipital ring narrow, flattened; occipital furrow very shallow; fixed cheeks narrow, separated from the glabella by distinctly marked dorsal furrows, and sloping rapidly from the palpebral lobes before and behind; palpebral lobes elongate, slightly sinuate, and with a groove within the margin; frontal limb broad, rather short, sloping down to a line or groove beyond which the flattened margin extends, the width of the margin nearly equaling the distance between it and the glabella; postero-lateral limits of medium width, with the extension of the occipital furrow marking their posterior portion; their lateral extension is a little greater than one-half the length of the head.
Facial suture directed outward from in front of the eyelobe to the anterior rim of the head, around which it abruptly curves, terminating at the front margin; behind the eye it passes obliquely backward at an angle of 25° with the posterior margin of the head, cutting the latter at a distance from the dorsal furrow equal to the width of the anterior emd of the glabella.
Surface finely granulose under a strong magnifying glass.
Thorax and pygidium unknown. One associated pygidium is much like that illustrated by Hall and Whitfield, Geol. Expl. Fortieth Par., vol. iv, pl. i, fig. 39.
Formation and locality—Cambrian. Upper portion of Prospect Mount- ain Group, near the Bullwhacker mine, Eureka District, Nevada.
Dicellocephalus Marica, n. sp. Plate x, fig. 13.
Glabella and fixed cheeks subquadrate in outline, narrowing somewhat towards the front. Glabella subquadrangular and almost squarely truncate in front, which is not quite as wide as the base; strongly convex, anil marked by three pairs of furrows, the two anterior pair but slightly im- pressed and very short; the. posterior pair extend obliquely inward one- third the distance across from each side, and are united by a slight trans- verse furrow; occipital ring strong and elevated; occipital furrow well defined; dorsal furrows strongly impressed; fixed cheeks moderately convex, narrow in front, widening at the palpebral lobes, and sloping away rapidly
in front, and less so back of the eyelobes; eyelobes narrow, semicircular,
FOSSILS OF THE CAMBRIAN. 45
and situated opposite the central portion of the glabella; frontal limb obsolete except the round, thick, marginal rim just in advance of the glabella; the posterior limbs are broken away at a little distance from the dorsal furrows. Surface, as seen under a strong magnifying glass, with fine inoscu- lating, flattened lines surrounding minute round or irregularly oval spaces. ~ Formation and locality—Upper beds of the Cambrian just south of the Hamburg mine, and in the same canon, Eureka District, Nevada.
Dicellocephalus ? quadriceps H. & W. Plate ix, fig. 24, Dikellocephalus ? quadriceps Hall & Whitfield, 1879. Geol. Expl. Fortieth Parallel, vol. iv, p. 240, pl. i, figs. 37-40.
Type specimens from the base of Ute peak, Wahsatch Range, Utah.
A careful comparison of the Wahsatch specimens with those from Nevada fails to give sufficient specific distinction to separate them on the evidence afforded by the material at hand. A small glabella with portions of the fixed cheeks attached is figured on plate ix, fig. 23, to show the peculiar form of the glabella and the disappearance of the very faint glabellar furrows, scarcely shown in the specimens from Utah; this repre- sents one extreme of the species, while the specimen illustrated in the Paleontology of the Geological Exploration of the Fortieth Parallel exhibits the other, or more mature form.
The generic reference is open to question, but with our present material little more can be done with it.
Formation and localities—Cambrian. Prospect Mountain Group, base of Secret Canon shale, New York Canon, and in Cambrian limestone on the west side of the Eureka District on the Antelope Valley slope, near the plain, Eureka District, Nevada.
Dicellocephalus ? expansus, n. sp. Plate ix, fig. 19.
Glabella elongate subquadrangular, or subclavate, the base about one- fifth narrower than the front; surface convex and without perceptible fur-
46 PALEONTOLOGY OF THE EUREKA DISTRICT.
rows; occipital furrow distinctly defined; occipital ring strong, with a small _ spine on the center of the posterior portion; dorsal furrows well defined along the sides of the glabella; fixed cheeks of medium width, palpebral lobes unknown; an ocular (?) ridge crosses the anterior portion of the right fixed cheek, so as to indicate a moderate sized eyelobe between it and the postero-lateral limb; frontal limb as a narrow rim; postero-lateral limbs rather narrow, extended and marked by a strong furrow within the poste- rior margin.
Surface finely punctate.
This species and the preceding are closely related, judging from the parts which we have for comparison. It is hoped that in some more favor able locality entire specimens may be obtained of these and the many other species known only by fragments, so that the generic characters can be determined with greater certainty and more positive specific references made.
Formation and localities —Cambrian. Prospect Mountain limestone at base of Secret Canon shale, in New York Canon, and also in a small expos- ure of Cambrian limestone on the west side of the Mahogany Hills, in Antelope Valley, Eureka District, Nevada.
Genus PTYCHOPARIA Corda.§ Ptychoparia (?) Prospectensis, n. sp. Plate ix, fig. 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 distinctly de- fined by a narrow, lightly impressed occipital furrow; fixed cheeks broad, of equal elevation with the glabella, and extending beyond it anteriorly, the space between them on the broad frontal limb being taken by a small
5The reason for using the generic term Ptychoparia rather than Crepicephalus, as used by Messrs. Hall and Whitfield in the Paleontology of the Fortieth Parallel Exploring Expedition, is given in a bulletin of the Geological Survey now ready for the press, entitled a ‘‘ Review of the Fauna of the St. John Formation.” The relations of the genera Conocoryphe, Ptychoparia, Crepicephalus, Soleno- pleura, Liostracus, and Conocephalites are mentioned.—C. D. W.
FOSSILS OF THE CAMBRIAN. AT
swelling or boss that, but for the slight transverse dorsal furrow between it and the glabella, might be mistaken for a continuation of the latter; the eyelobes are comparatively large for a species of this character and occupy a prominent position on the outer margin of the cheeks, a distinet ocular ridge 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 slope rapidly downward back of the eyelobes; frontal limb broad at the center, narrowing in front of the fixed cheeks and bor- dered anteriorly by a not very distinctly defined rounded margin. The facial suture curves a little inward in front of the eye and appears to ter- minate 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, out- lining an elongate triangular postero-lateral limb.
Under a strong magnifying power the surface is seen to be finely gran- ulose.
Free cheeks, thorax, and pygidium unknown.
Formation and locality—Cambrian. Mountain shale band of the Pros- pect Mountain Group, on the east slope of Prospect Peak, Eureka District, Nevada.
Ptychoparia (?) Linnarssoni, n. sp.
Plate ix, figs. 18, 184.
The glabella and fixed cheeks are the only portions of this interesting species that have been identified. The glabella is small in proportion to the area occupied by the cheeks and frontal limb; it is conical in form, truncate in front, moderately convex, and marked by three pairs of very short, slightly impressed glabellar furrows; the latter only observed on very perfect specimens; occipital ring narrow, as also the shallow occipital fur- row; fixed cheeks broad, elevated, and projecting forward on to the frontal limb considerably in advance of the front of the glabella, the included space between their anterior portions being occupied by an elongate oval boss that is separated from the glabella by a rather broad, shallow furrow; the boss or tubercle extends to the rounded thick frontal rim, from which it
48 PALEONTOLOGY OF THE EUREKA DISTRICT.
is defined by a scarcely perceptible depression; dorsal furrows broad, well defined, and running out in front much broader between the tubercle and the fixed cheeks; palpebral lobes rather prominent and situated opposite the anterior end of the glabella; postero-lateral limbs long, triangular, and marked by a strong furrow within their posterior margin. Facial suture directed forward in front of the eyelobes, curving outward a trifle and then a little inward on the frontal limb, around the front of which it does not appear to extend; back of the eyelobe it extends obliquely outward and backward, bending a little more abruptly backward towards the lateral ex- tension of the limb, terminating at or just within the genal angle at a dis- tance from the dorsal furrow equal in one example to the entire length, and in another to two-thirds of the length of the head.
Surface minutely granulose.
The specific name is given in honor of Dr. G. Linnarsson, the eminent Swedish paleontologist.
This species is allied to P. Prospectensis, but differs in the position of the eyelobes and the larger frontal limb, changes, however, that may be only varietal, as there is an interval of 3,000 feet of strata between the horizons at which they respectively occur, but for the present they are regarded as distinct species. They are strongly marked forms and types of a group of the genus not specially recognized heretofore, as they unite the presence of a tuberosity in front of the glabella, seen only (with the excep- tion of Ptychoparia calymenoides Whitfield) in the eyeless trilobites, Cono- coryphe coronatus Barr., C. exsulans Linnarsson, C. Matthewi Hartt, C. Solvensis Hicks, C. (Elyx) laticeps Angelin, with the presence of fully-developed eyes and the direction of the facial sutures as in Ptychoparia striatus, ete. I am not at all certain that P. calymenoides should be included with them, as the tuberosity in that species maybe only an unusual thickening of the frontal rim of the head and not the true frontal limb, a question not readily deter- mined with the specimens thus far obtained
Formation and locality— Cambrian. Prospect Mountain Group, in the upper beds of the Secret Cation shale, on the east side of Secret Canon, opposite the Geddes and Bertrand mine, Eureka District, Nevada.
FOSSILS OF THE CAMBRIAN. 49
Ptychoparia (Solenopleura?) breviceps, n. sp
Plate x, fig. 9.
Head rather small, convex, semicircular; length a little less than one- half the width of the posterior margin. Glabella large, prominent; length and width at the base nearly equal, converging rapidly towards the trun- cated front to three-fifths the width of the base; the posterior glabellar furrow extends entirely across, while the two anterior pairs are scarcely discernible; occipital ring transverse, rounded, separated from the glabella by a strong, rounded furrow, and extending laterally as the narrow rounded posterior border of the head; dorsal furrows strongly defined; fixed cheeks convex, depressed below the level of the glabella, rather wide and sloping abruptly to the frontal border, slightly depressed towards the small palpe- bral lobes and sloping away rapidly posteriorly; ocular ridges strongly marked, trending obliquely backward from the antero-lateral angles of the glabella; postero-lateral limbs rather narrow, distinctly grooved on the posterior edges by the occipital furrows; frontal limb obsolete, the strong, rounded, marginal border touching the anterior margin of the glabella. Facial suture curves slightly inward in its course from the eyelobe to the front margin of the head, and apparently cuts obliquely inward across the frontal rim; behind the eye it is directed outward, curving a little backward to the posterior margin and outlining an elongate triangular lateral limb.
Surface apparently smooth or very finely punctate.
Formation and locality—Cambrian. Prospect Mountain Group, in the Hamburg shale belt north of Adams Hill, Eureka District, Nevada.
Ptychoparia (?) pernasutus, n. sp.
Plate x, figs. 8, 8 a-b.
Entire form unknown. The glabella and fixed cheeks, and the free cheeks associated with them, give the head a rounded, subtriangular form; it is strongly convex and produced anteriorly ina strong, elongate, flattened triangular process, the anterior third of which bends downward with a uni- form curvature; the width of the process at the base is about two-thirds of
40DW
50 PALEONTOLOGY OF THE EUREKA DISTRICT.
its length from the marginal furrow; laterally it passes into the strong rounded border of which it is an extension.
Glabella strongly convex, broadly conical in outline and rounded truncate in front; the greatest breadth near the base is five-sixths of the length from the occipital furrow to the front; three pairs of furrows divide it into three posterior subequal lobes and one smaller anterior lobe; the poste- rior furrows penetrate obliquely backward nearly two-thirds the distance to the median line, while the two anterior pairs are short and but slightly im- pressed; occipital furrow broad and well defined, with a small triangular- shaped node at each postero-lateral angle of the glabella; occipital ring strong and narrowing towards the dorsal furrows. Only small portions of the fixed cheeks are preserved; these show the presence of strongly-defined dorsal furrows around the glabella, and that the cheeks sloped up rapidly from them towards the palpebral lobes, which, from the associated free cheek, must have been of rather large size and not far from the glabella, giving a somewhat narrow fixed cheek; the anterior limb has a length of about one-fifth of that of the glabella from the occipital furrow, it is slightly convex and slopes into the rather strong furrow between it and the nasute- like extension of the marginal border, its anterior margin forming an obtuse angle at the median line.
The associated free cheek is subtriangular in outline, strongly convex, with a wide, strong marginal border and groove, and a spinous extension of the genal angle, with the anterior margin extended beyond the union of the cheek with the margin, the interior angle is hollowed out for the recep- tion of a large eyelobe.
Surface granulose and probably pustulose on the glabella.
This is a large and unusually striking species. In the extension of the frontal border it is like Anomocare acuminatum Angelin, a feature not here- tofore observed in any American species from this horizon.
Formation and locality—Summit of the Cambrian, Prospect Mountain Group, east side of the cation east of the Hamburg Ridge, Eureka Dis- trict, Nevada.
FOSSILS OF THE CAMBRIAN, yt
Ptychoparia (Euloma ?) dissimilis, n. sp. Plate ix, fig. 28.
Glabella prominent, strongly convex, the anterior lobe curving down- ward and under to the frontal margin; length and width at the base equal; marked by two pairs of glabellar furrows extending obliquely inward, the posterior pair nearly cutting off the triangular-shaped posterior lobes; occip- ital ring broad at the center, narrowing laterally; occipital furrows strongly impressed, as are the dorsal furrows along the sides of the central and pos- terior portions of the glabella; fixed cheeks very narrow; palpebral lobes large, moderately elongate, slightly sinuous, with a strong groove within the margin; frontal lobe a narrow rounded rim; postero-lateral limbs un- known.
This species is known only by the parts mentioned. It is allied to Ptychoparia Eos Hall, and a somewhat similar form has been described as Menocephalus Sedgwicki Billings. They appear to form a small group of the Conocephalide, the limits of which have not been defined. The refer- ence to the genus Menocephalus is of doubtful propriety, since, up to the present time, the fragment referred to as the type by Owen has never again been even generically or specifically recognized in all the great collections from the Potsdam sandstone of the Wisconsin and Minnesota, and it appears to be practically impossible to identify it. The two species referred to the genus by Billings, Palzeozoic Fossils, vol. i, p. 407, and Geology of Canada, p. 237, also appear to belong to two distinct genera.
Formation and locality—Cambrian. Secret Canon shale of the Prospect Mountain Group, New York Canon, Eureka District, Nevada.
Ptychoparia occidentalis, n. sp. Plate x, fig. 5.
Head within the facial sutures, exclusive of the postero-lateral limbs, quadrangular in form; glabella subconical, the sides slightly converging towards the rounded front; surface uniformly convex and marked by three pairs of moderately oblique glabellar furrows, the two posterior pairs of
52 PALEONTOLOGY OF THE EUREKA DISTRICT.
which are more strongly impressed and reach two-thirds the distance to the
median line, the anterior -pair are short and faintly defined; occipital furrow ~ distinct; occipital ring rounded and rather under the medium size; dorsal
furrows well impressed on the sides and in front of the glabella; fixed
cheeks of medium width, not very convex, and sloping away gradually in front and behind; ocular ridges well marked; frontal limb extended a little
beyond the fixed cheeks, slightly convex, and bordered by a flattened rim
that is two-thirds as wide as the width between it and the glabella; eye-
lobes of medium size; postero-lateral limbs narrow, extended, with a
strongly marked continuation of the occipital furrow just within their pos-
terior margin. The facial suture cuts very obliquely across the frontal rim
of the head and abruptly recurving inward at its interior margin passes
slightly inward in a direct line to the eyelobe, back of which it is directed
outward with a backward curve on the outer third of the lateral limb, to the
posterior margin of the head, which it cuts at a distance from the dorsal furrow
equal to the width of the base of the glabella.
Surface of head finely granulose; striate on the frontal limb.
In the general outline of the facial sutures this species might be referred to Dicellocephalus, but the glabella is of the true type of Ptychoparia, and the other parts are not incompatible with a reference to that genus.
Formation and locality.—Cambrian. Prospect Mountain Group, at the base of the Secret Canon shale on the west side of Secret Canon, Eureka District, Nevada.
Ptychoparia similis, n. sp. Plate x, fig. 10.
The glabella and fixed cheeks form a subquadrangular outline, with the central portion, opposite the eyes, arching inward, the frontal and postero-lat- eral limbs terminating the angles; glabella broadly conical, sides straight, converging slightly anteriorly to the rounded frontal margin; surface strongly convex and broken by three pairs of furrows, the anterior of which are very faint, the middle pair somewhat stronger and the posterior still more so; all are deflected a little backward, the posterior pair strongly outlining the pos- terior lobes; occipital ring strong and full and separated by a deeply im-
FOSSILS OF THE CAMBRIAN. 53
pressed occipital furrow; dorsal furrows distinct at the front and sides of the elabella; fixed cheeks narrow and rising rapidly from the dorsal furrows to the palpebral lobes, sloping away somewhat abruptly to the front and back; frontal limb short and broad, convex, and sloping quite rapidly to the slight furrow within the broad, planulate margin, which appears to be a continua- tion of it; postero-lateral limbs narrow, posterior margins rather strong, with a narrow groove within.
Surface of the glabella finely pustulose.
This species is allied to P. Montanensis Whitfield, but differs in the character of the frontal limb very decidedly, as also in the planulate margin. Some of the examples show the front margin cut away by the suture line which crosses it obliquely from about one-third the distance from the center, at its front margin, to the postero-lateral angle.
Formation and locality—Cambrian. Prospect Mountain Group, in the upper beds of the Secret Canon shale across the cation opposite the northeast dump of the Richmond mine shaft, Ruby Hill, Eureka District, Nevada.
Ptychoparia similis, var. robustus, n. var. Plate i, figs. 9, 9a.
Glabella and fixed cheeks subquadrangular in outline. Glabella ob- tusely conical, sides slightly converging to the rounded front; surface convex, marked by two pairs of rather short, slightly impressed, oblique furrows; occipital ring strong, with a well-defined occipital furrow; dorsal furrows well defined in front and at the sides of the glabella; fixed cheeks narrow, rising rather rapidly from the dorsal furrows up to the front of the small palpebral lobe and then arching over to unite with the short, rounded frontal limb ; ocular ridges well marked; frontal margin rather broad and flat; postero-lateral limbs narrow as in P. similis. Surface of the glabella and postero-lateral limbs finely pustulose.
This species, in the parts preserved, is closely allied to P. similis. The glabella is shorter, more convex, and nearly as broad as long, while that of P. similis is one-fourth longer than broad. The entire appearance gives the idea of its being a robust form of P. similis.
Formation and locality —Same as Ptychoparia similis.
54 PALEONTOLOGY OF THE EUREKA DISTRICT.
Ptychoparia (Euloma ?) affinis, n. sp. Plate x, fig. 12.
General form and appearance much like that of P. similis, but differing in its more pronounced convexity, in the more deeply impressed two poste- rior pairs of glabellar furrows and the rounded marginal rim instead of the long planulate margin; features that render the two very distinct. Surface finely pustulose. Mr. E. Billings has described an allied form from Canada as Menocephalus Sedgwicki, the generic reference of which is very doubtful.
Formations and localities —Cambrian and Silurian. In the limestones or passage beds between the Prospect Mountain and Pogonip Groups above the Hamburg belt of shale east of the Hamburg mine, and in the lime- stone of a little higher horizon northeast of Adams Hill, Eureka District, Nevada.
Ptychoparia leviceps, n. sp. Plate x, figs. 17, 18.
General form of head within the facial sutures subtrapezoidal. Glabella conical, strongly convex, with very faintly defined dorsal furrows separat- ing it from the rapidly sloping fixed cheeks; two pairs of furrows are just discernible by slight impressions on the surface; occipital ring strong, rounded, separated from the glabella by a shallow furrow; fixed cheeks of medium width, sloping rapidly down from the glabella and from the small eyelobe, situated a little back of the center, to the front and back; frontal limb short, convex, and depressed to the broadly rounded, strong, marginal rim; postero-lateral limbs rather strong and running out beyond the line of the lateral extension of the frontal limb.
Surface smooth to the unaided eye; under a strong magnifying power, minutely granulose.
This species is peculiar in the absence of strongly marked furrows and the general smooth appearance, as though all strong outlines had been removed by rubbing off the outer surfaces. In form it resembles the follow- ing species and is closely allied to it. It differs from it in the general ap- pearance and also in the course of the facial sutures in front of the eyes.
FOSSILS OF THE CAMBRIAN. - 55
Formation and locality—Cambrian. Prospect Mountain Group, upper beds of the Secret Cation shale on the east side of Secret Canon, Eureka District, Nevada.
Ptychoparia Oweni M. & H. Plate x, figs. 3, 3a.
Arionellus (Crepicephalus) Oweni Meek & Hayden, 1861. Proc. Acad. Nat. Sci. Philad., vol. xiii, p. 436.
Arionellus ? Oweni Meek & Hayden, 1862. Amer. Jour. Sci., 2d Series, vol. xxxiii, p. 74.
Agraulos Oweni Meek & Hayden, 1864. Pal. Upper Missouri, p. 9, figs. A, B, C.
Agraulos ? Meek & Hayden, 1864. Pal. Upper Missouri, p. 10, pl. i, fig. 4.
OD
Conocoryphe (Ptychoparia) Gallatinensis Meek, 1873. Sixth Ann. Rep. U.S. Geol. Sury. Territories, for the year 1872, p. 485.
Crepicephalus (Loganellus) centralis Whitfield, 1877. Prelim. Rep. Pal. Black Hills,
a Whitfield, 1881. Rep. Geol. and Resources Black Hills of Da- kota, p. 341, pl. ii, figs. 21, 24.
I was somewhat surprised on bringing together the types of Arionellus = Ptychoparia Owent, Conocoryphe = Ptychoparia Gallatinensis, and Crepi- cephalus == Ptychoparia centralis, to find that they were representatives of one somewhat variable species. The types of P. Oweni and P. centralis are abso- lutely identical, while P. Gallatinensis is only a variety of P. Oweni that shows a wider range of variation, owing to the fact that we have a larger series of specimens representing it. One of these variations is shown in the Black Hills specimen figured by Meek and Hayden as Agraulos ? —————, and labeled (probably by Mr. Meek) in the collection of the Smithsonian Insti- tution as Conocephalites sp. ?
The Nevada species is the same as that from the Gallatin River, Mon- tana, and the Black Hills of Dakota. It presents much the same variations in size, and the presence or absence of the glabellar furrows is a noticeable feature in each. Some of the younger specimens resemble Conocephalites = Ptychoparia arenosus Bill., from the Potsdam sandstone of Vermont, but dif- fer in the width of the fixed cheeks and frontal limb.
P. Oweni ranges through nearly 4,000 feet of strata, being found in the Prospect Mountain limestone of the 700-foot level of the Richmond mine and well up in the Pogonip Group on the ridge east of the Hamburg mine,
56 PALEONTOLOGY OF THE EUREKA DISTRICT.
and at various horizons between the two in New York, Secret, and Sierra Cafions, and on the Hamburg Ridge. In the Black Hills it occurs at about the horizon of the upper portion of the Prospect Mountain Group of the Eureka District, Nevada.
In a report on the Cambrian fauna of the United States, now in course of preparation, the types of the various species given in the synonymy of Ptychoparia Oweni will be illustrated.
Ptychoparia Anytus H. & W. Plate ix, fig. 26. Orepicephalus (Loganellus) anytus Hall & Whitfield, 1877. Geol. Expl. Fortieth Par., vol. iv, p. 219, pl. ii, figs. 19-21. Compare Crepicephalus=Ptychoparia planus Whitfield, 1877. Geology and Resources of the Black Hills of Dakota, p. 341, pl. ii, figs. 21-24. Also Crepicephalus (L.) = Ptychoparia Montanensis Whitfield, 1876. Rep. Recon. Carroll, Montana, to Yellowstone Nat. Park, Ludlow, p. 141, pl. i, figs. 1, 2. The specimen illustrated by fig. 26 of plate ix, differs from the type of P. Anytus in having a somewhat narrower, more quadrilateral glabella, and also a thicker anterior rim to the head, but on comparing several spe- cimens with the typical specimens from Schell Creek, Nevada, these varia- tions are seen in each series, and no satisfactory differences remain upon which to base a distinct species. The figure given by Messrs. Hall and Whitfield shows a larger, broader, and more conical glabella in proportion to the head than that of fig. 26, plate ix, of this report, the two figures in the two reports giving the range of variation in the head as far as known. On comparing the type of P. planus Whitfield, with a head of P. Anytus, broken just as the type of P. planus is, there does not appear to be the slightest difference between the two. We labor, however, under the dis- advantage of comparing with a cast of a fragment of the head as the origi- nal type, and cannot decide positively until more and better material is collected from the original locality. P. Montanensis is a closely allied species of which we have not seen the original type. Formation and locality—Cambrian. In the upper beds of the Secret Canon shale, on the east side of New York and Secret Cafions, Eureka District, Nevada. i
FOSSILS OF THE CAMBRIAN. 5T
Ptychoparia granulosus H. & W.
Grepicephalus (Loganellus) granulosus Hall & Whitfield, 1877. Geol. Expl. Fortieth Par., vol. iv, p. 214, pl. ii, figs. 2, 3.
Types from the Eureka District. The species occurs at the summit of the Secret Cafion shale, across the cation from the dump of the Richmond shaft, Ruby Hill, and in the lower part of the Pogonip Group, southeast of the Jackson mine, Eureka District, Nevada.
Ptychoparia Haguei H. & W.
Orepicephalus (Loganellus) Haguei Hall & Whitfield, 1877. Geol. Expl. Fortieth Par., vol. iv, p. 210, pl. ii, figs. 14, 15.
Types from Pogonip Mountain, White Pine District, Nevada.
In the Eureka District this species has a range nearly equal to that of P. Gallatinensis, but, as yet known, it does not extend down below the sum- mit of the Secret Cafion shale. At that horizon it occurs on the eastern side of Secret Cation and the opposite side of the cation from the dump of the Richmond shaft, Ruby Hill, and at the summit of the Hamburg shale east of the Hamburg mine, and also in the lower part of the Pogonip Group at the same locality.
Ptychoparia nitidus H. & W.
Orepicephalus (Loganellus) nitidus Hall & Whitfield, 1877. Geol. Expl. Fortieth Par., vol. iv, p. 212, pl. ii, figs. 8-10.
Crepicephalus (Loganellus) simulator Hall & Whitfield, 1877. Geol. Expl. Fortieth Par., vol. iv, p. 218, pl. ii, figs. 16-18.
When studying a large series of specimens of Ptychoparia nitidus it was observed that the head and pygidium varied in size, and that there were no differences between the larger sized specimens of the head and the type of Crepicephalus (L) simulator.
The types of the two species described by Messrs. Hall and Whitfield were collected in the Eureka District by the geologists of the Fortieth Par- allel Exploring Expedition, and the species is quite abundant in strata near
the summit of the Cambrian series.
.
58 PALEONTOLOGY OF THE EUREKA DISTRICT.
Formation and localities—Hamburg shale, in the Widewest Ravine north of Adams Hill, and also from the same horizon a short distance south of the Hamburg mine on the east side of the same canon, Eureka District, Nevada; also at about the same horizon on Pogonip Ridge, White Pine District, Nevada.
Ptychoparia unisuleatus H. & W.
Crepicephalus (Loganellus) unisulcatus Hall & Whitfield, 1877. Geol. Expl. Fortieth Par., vol. iv, p. 216, pl. ii, figs. 22, 23.
The types of this species are cited by its authors as coming from the limestone of the Potsdam Group at Eureka, Nevada. It is found associated with P. Haguei, in the upper beds of the Secret Canon shale, opposite the dump of the Richmond mine shaft, Ruby Hill, on the northeast side of the canon, and in the lower portion of the Pogonip Group, northeast of Adams
Hill. It also occurs in the lower portion of the Pogonip Group, on Pogonip . Ridge, White Pine District, Nevada.
Subgenus PTEROCEPHALUS Roemer. Ptychoparia (Pterocephalts) occidens, n. sp.
Plate ix, fig. 21.
Glabella and fixed cheeks, when united, irregularly elongate-quad- rangular in outline, exclusive of the postero-lateral limbs; widést across the frontal lobe, and curving in towards the eyelobes; greatest width five- sixths of the length. Glabella broadly conical, rounded in front, and mod- erately convex; marked by a pair of short posterior furrows.
Occipital ring narrow, rounded, separated from the base of the gla- bella by a narrow, distinct occipital furrow; fixed cheeks rather narrow; palpebral lobes small, and situated opposite the central portion of the gla- . bella; frontal limb expanded, its length equaling more than one-third the entire length of the head; concave from the front to the back, and appar- ently without a raised anterior rim; postero-lateral limbs extended, the suture line cutting the posterior margin some distance beyond the line of
FOSSILS OF THE CAMBRIAN. 59
the eyelobes; marked near the posterior margin by the extension of the occipital groove. Facial suture extends outward, with a slight curvature in front of the eyelobe, and then recurves, rounding the lateral extension of the frontal limb; behind the eye it extends backward and outward at an angle of about 45° for a short distance, and then continues at an angle of 25° to the posterior margin of the head.
Dimensions.—Length of head, 6"; breadth of frontal lobe, 2.25™"; length of glabella, including occipital ring, nearly 3.75".
This distinct form appears to belong to that division of the Concepha- lidze represented by Roemer’s genus Pterocephalus, judging by its wide frontal limb and the course of the facial sutures.
Formation and locality—Upper beds of the Cambrian. On the east side of the canon east of the Hamburg Ridge, Eureka District, Nevada.
Ptychoparia (Pterocephalus) laticeps H. & W.
Concephalites (Pterocephalus) laticeps Hall & Whitfield, 1877. Geol. Expl. Fortieth Par., vol. iv, p. 221, pl. ii, figs. 4-7.
This species is given by its authors as occurring in the lowest lime- stones on the west side of Pogonip Mountain, White Pine District, Nevada. In the Eureka District it is found in the upper beds of the Secret Canon shale, opposite the dump of the Richmond mine shaft, Ruby Hill, northeast side of the canon, and in the Hamburg belt of shale east of the Hamburg mine, Eureka District, Nevada.
Genus ANOMOCARE Angelin. Anomocare ? parvum, n. sp. Plate ix, fig. 17. Glabella and fixed cheeks united, subquadrangular in form, moderately convex. Glabella tapering gradually from the base to the front, where it is rounded truncate; the surface is depressed convex and marked by four
pairs of glabellar furrows, which are short, slightly impressed, and divide the glabella into three subequal lobes, with a somewhat longer anterior
60 PALEONTOLOGY OF THE EUREKA DISTRICT.
lobe; occipital ring strong, swollen towards the eenter, and bearing a short spine; occipital furrow well defined; dorsal furrows blended with the de- pressed interior slope of the fixed cheeks and frontal lobe; this causes the glabella to stand out prominently, although but little elevated above the - general surface of the head; fixed cheeks rather broad, with a rounded, ridge-like elevation near the eyelobes, and sloping inward to form a de- pressed space before reaching the glabella; eyelobes large, with an ocular ridge running towards the anterior lobe of the glabella; frontal lobe short and convex, merging into the fixed cheeks laterally, and in front into the strong furrow within the broad, marginal border; the border is convex and swollen at the center into a small protuberance; postero-lateral limbs nar- row and rather depressed.
Surface finely granulose.
The identification of the genus Anomocare is made with the illustra- tions given by Angelin, and, until we know more of the structure of the species under consideration, it is difficult to give any other generic refer- ence. No pygidie or remains of the thoracic segments were found in the same association.
Formation and locality—Cambrian. In a limestone beneath the arena- ceous shales carrying the species of Olenellus, given on a previous page, and associated with 0. Gilberti and O. Howelli. West slope of Prospect Mountain, Eureka District, Nevada.
Genus PTYCHASPIS Hall.
Ptychaspis minuta Whitfield (?). Plate x, fig. 23. Ptychaspis minuta Whitfield, 1878. Ann. Rep. Wisconsin Geol. Surv., p. 55. Ibid., Geol. Wisconsin, vol. iv, p. 186, pl. i, figs. 25, 26, 1883. ‘
This is a very minute form, the head measuring only about 3™ in length. A comparison of the glabella and fixed cheeks, the only parts thus far discovered, with the description of the original type specimens from the Potsdam sandstone of Wisconsin, shows such close resemblances between the two that with our present knowledge it appears impossible to consider
FOSSILS OF THE CAMBRIAN, 61
them as specifically distinct. The frontal limb scarcely projects beyond the front line of the glabella, as it slopes abruptly downward, although it is represented as projecting out some distance in the specimen illustrated owing to a narrow seam of calcite crossing it and throwing it forward.
Formation and locality—Cambrian. Prospect Mountain Group, eastern base of Lookout Mountain, Sierra Valley, Eureka District, Nevada.
Genus CHARIOCEPHALUS Hall. Chariocephalus (?) tumifrons H. & W. Plate x, fig. 16.
Chariocephalus tumifrons Hall & Whitfield, 1877. Geol. Expl. Fortieth Par., vol. iv, p. 224, pl. ii, figs. 38, 39.
The types of this species came from the lower limestones of Pogonip Mountain, in the White Pine District, Nevada. :
The specimen illustrated as the type of the species is the extreme form attained by the adult. Traced ina series of individuals, towards the younger form, the anterior lobe of the glabella is seen to lose its tumid, projecting character, and to curve down to the frontal margin and not overhang it, as in the older individuals. One of the intermediate phases of growth is shown by fig. 16, plate x.
Formation and locality—Cambrian. In the upper beds of the Secret Cafion shale on the north side of the canon, opposite the dump of the shaft of the Richmond mine on Ruby Hill, Eureka District, Nevada.
Genus AGRAULOS Corda. Agraulos ? globosus, n. sp. Plate ix, fig. 23.
Glabella and fixed cheeks, exclusive of the postero-lateral limbs, sub- quadrate, strongly convex. Glabella with the sides and front rounded, convex, and with the surface apparently smooth; dorsal furrows well defined; occipital ring not perceptibly separated from the glabella; fixed cheeks of medium width; palpebral lobes small, the cheeks sloping down to them; frontal limb about one-third as long as the glabella, convex, with- out an apparent marginal rim, and with a slight furrow at the union with
62 PALEONTOLOGY OF 'THE EUREKA DISTRICT.
the fixed cheeks; postero-lateral limbs strong, extended laterally and with a distinct marginal furrow, which is usually the continuation of the occipital furrow. Facial suture directed gently forward from the eyelobe towards the front, recurving to the frontal margin of the head so as to round the lateral angles of the frontal limb; behind the eye it passes to the posterior margin at an angle of 20°-25° with the latter, outlining a triangular-shaped lateral limb.
This peculiar little species (the head is but 3"™ in length) appears to unite some embryonic features with those of the adult individual. It is doubtfully referred to Agraulos. The discovery of allied species or more specimens of this one may enable the observer to determine more fully its true generic relations.
Formation and locality—Cambrian. In a small outcrop of limestone on the west side of the Eureka District, Nevada.
Genus ARETHUSINA Barrande. Arethusina Americana, 0. sp. Plate ix, fig. 27.
Glabella and fixed cheeks united, a little wider than long, the front broadly rounded, and the sides a little contracted midway. Glabella promi- nent, conical, convex, rounded in front, and marked by two pairs of short furrows extending obliquely inward less than one-fourth the distance across; occipital ring narrow, defined by a shallow occipital furrow; fixed cheeks broad, sloping away from the well-defined dorsal furrows to the minute palpebral lobes; well-marked ocular ridges cross from opposite the anterior portion of the glabella to the eyelobes; all in front of these is occupied by the broad, expanded frontal limb; it is slightly convex to the anterior narrow marginal rim; postero-lateral limbs but little extended lat- erally and with a marginal groove within the posterior border. Facial suture extends a little outward in a gentle curve to the frontal margin from the eyelobe, recurving just before reaching the margin; behind the eys- lobe it is directed obliquely backward, outlining a triangular lateral limb and cutting the posterior margin at a distance from the dorsal furrow equal to the width of the glabella at its base.
FOSSILS OF THE CAMBRIAN. 63
Surface of the glabella minutely granulose; the frontal limb has a peculiar ornamentation formed by irregular inoseulating lines that in their general direction radiate towards the anterior rim.
With the portions of this species we have before us, it appears to be related to Arethusina more closely than any other described genus. The posterior glabellar furrows are less oblique than in the Bohemian species, . but otherwise there is a strong generic resemblance between them.
Formation and localities—Upper beds of the Cambrian. On the ridge north of the Dunderberg mine, at about the same horizon on the north side of the canon north of Adams Hill, and also in the Pogonip Group, on the second ridge southeast of the Jackson mine, Eureka District, Nevada.
Genus OGYGIA Brongniart. Ogygia ? spinosa, n. sp. Plate ix, fig. 22.
Glabella elongate, not quite twice as long as wide; sides parallel nearly to the front, which is slightly expanded and broadly rounded ante- riorly; moderately convex and subangular along the median line; marked by three pairs of oblique furrows that extend one-third the distance across; occipital ring strong, not very convex, and with a rather strong central spine projecting backward and upward; occipital furrow shallow, well defined; fixed cheeks narrow; palpebral lobes large, rising slightly from the dorsal furrows to the depressed furrow just within and parallel to their margins; frontal limb convex, of medium width and length, and bordered by a flattened rim. The presence of the strong occipital spine is one of the most distinct characters of this species.
Formation and locality—Cambrian. Prospect Mountain Group; at the base of the Secret Camion shale in Secret Canon, Eureka District, Nevada.
Ogygia ? problematica, n. sp. Plate x, figs. 2a-b, and 4.
Glabella elongate, clavate, expanding regularly from the base to a width one-third greater in front; moderately convex behind, becoming
64 PALEONTOLOGY OF THE EUREKA DISTRICT.
almost tumid on the frontal lobe, and in compressed examples slightly projecting over the anterior margin; marked by three pairs of oblique, slightly impressed furrows; these are united across the center by short transverse depressions; occipital furrow shallow; occipital ring strong, flattened; fixed cheeks of medium width, separated from the glabella by distinct but lightly impressed dorsal furrows, and sloping outward to the medium-sized eyelobes; postero-lateral limbs strong and well extended laterally; frontal limb as a narrow margin close to the front of the glabella.
The facial sutures have the general course of those in the genera Ogygia and Asaphus.
The above description is drawn from a well-preserved adult specimen of the head, that, excepting the free cheeks, is 23™™ in length. In a young example of the same parts, 7™" in length, the glabella is less convex, subangular in front, sloping to the margin, and the glabellar furrows are obsolete; in other respects it strongly resembles the adult.
With these parts before us we would refer the species to Ogygia; but in every instance where they have been found there are pygidie, tho- racic segments and fragments associated with them that indicate an entirely different genus. An illustration is given of the pygidium on plate x, fig. 2a, and of the segment, fig. 2b. They occur in association along an out- crop of several miles, and no other species of a similar size is known to exist at the same horizon. No genus known to us combines the characters presented by the head and pygidium, and, although they have not been seen united to the thorax, the evidence is in favor of their belonging to the same species.
A provisional reference is made to Ogygia, the genus to which the head appears to belong, the pygidium and thoracic segments having more the character of those referred to Dicellocephalus.
Formation and localities Cambrian. Prospect Mountain Group, upper beds of the Secret Canon shale, on the east side of Secret and New York Canons, and on the south slope of Adams Hill, Eureka District, Nevada.
FOSSILS OF THE LOWER SILURIAN. POGONIP GROUP.
RHIZOPODA.
Genus RECEPTACULITES Defrance.
Receptaculites mammillaris Newberry.
Plate xi, fig. 11. Receptaculites mammillaris Newberry, 1880. Name proposed in manuscript.
There is quite a range in the forms taken by this species, the most prevalent of which is an inverted cone with a deep depression on the upper surface, the height being to the diameter of the summit as four to five. In the more expanded examples, with the height and diameter as one to two, the base is small, and when the specimens are reversed, form a nipple- like projection on the’summit of the broadly rounded surface. The walls have a thickness of about 18™", in examples from 40™™ to 50™™ in diam- eter.
The outer surface or ectorhin is formed of rhomboidal plates arranged in radiatingly curved lines crossing each other obliquely; the plates near the base have a greater diagonal axis of 1™, which gradually increases to 2.5™ in the plates towards the summit; the only surface character preserved is a slight depression in the center of each plate. The cylindrical tubes uniting the ectorhin and endorhin have the characteristic construction of such tubes in Receptaculites near the base, but have not the connecting stolons or tubes between the constrictions and the ectorhin. Their absence may be owing to the imperfect condition of the specimens examined. Along the upper portion of the tubes there is a series of annulations, ten in a distance of 6™, that appear to be made up of little projections or stolons uniting
the tubes on the upper annulations. 5cDW 65
66 PALEONTOLOGY OF THE EUREKA DISTRICT.
In the mode of growth and general form this species is related to R. Neptuni, but differs in the details of structure. .
Several years since Dr. J. S. Newberry obtained examples of the species from the White Pine Mining District, and also from Pioche, Nevada, proposing the specific name &. mammilaris, in his notes, on account of the appearance of the more expanded forms with the nipple-like base. An illustration is given of the most abundant form in the Eureka District. The complete illustration of this and its associated species of the genus is deferred until sections can be prepared to exhibit the details of structure.
Formation and localities—Upper portion of the Pogonip Group at Lone Mountain, 18 miles northwest of Eureka; White Mountain, Fish Creek Mountains, and Goodwin Canon in the Eureka District; and also at Pioche and Treasure City, White Pine Mining District, Nevada.
Receptaculites elongatus, n. sp.
The general form of this species is cylindro-conical, with the central depression extending deep down into the body, the thickness of the sides near the base and at the summit being nearly the same. The outline of the central depression is circular, and there is no evidence of the growth of the sides over it as in some species of the genus from Canada and Wisconsin, e. g., R. Jonesi, R. fungosum, etc. The ectorhin is formed of small rhomboidal plates, arranged as in other forms of the genus; the largest plates have a greater diagonal diameter of about 1™", and a lesser one of about five-sixths of 1™™. The cylindrical tubes uniting the ectorhin and endorhin are small, constricted at the base, and apparently smooth up to their union with the plates of the endorhin. The sides of a specimen 45™ high, and with a transverse diameter of 20", have a thickness of 7™™ above and of 5™™ near the base
This species is distinguished from any known to me by its cylindro- conical form, deep central cavity, and small cells or tubes. It approaches R. insularis Billings, of the Middle Silurian of the island of Anticosti (Cat. Sil. Foss. Anticosti, p. 29, 1866), but differs in having the deep central de- pression and a less rapidly tapering form; these features, united with the fact
FOSSILS OF THE LOWER SILURIAN. 67
of the great vertical difference in the geologic horizon at which the two forms occur, render the probability of a specific identity very doubtful.
Formation and localities. Upper portion of the Pogonip Group, White Mountain and Goodwin Canton, Eureka District, Nevada. Also in the col- lection of the School of Mines, Columbia College, New York, collected by Dr. J. 8. Newberry in the Pahranagat Range, Nevada.
Receptaculites ellipticus, n. sp. Plate xi, fig. 12.
This is an elongate, flattened, curved form, with a strongly elliptical transverse section, the curvature being with the major diameter of the section. The central depression is deep, but not as large proportionally as in R. elongatus. The plates of the ectorhin are of medium size, 1.75™™ by 1.25™, and arranged as in the preceding species. The cylindrical tubes uniting the ectorhin and endorhin are strong and appear to be round and smooth, except where marked by the constriction and connecting basal stolons. The plates of the endorhin are concealed by the adhering matrix in all the examples in the collection.
The illustration shows the curvature and general form of a well-marked example of the species. It is specifically distinct from any described form that we know of, although allied to Receptaculites infundibulus Hall (Rep. Geol. Surv. Wisconsin, 8vo, pam., p- 16, 1861) = Ischadites tessellatus Win- chell and Marcy, of the Niagara Group of Illinois (Mem. Bos. Soc. Nat. Hist., vol. i, p. 85, pl. ii, fig. 3, 1865), from which it differs in the size of the ectorhinal plates and other details of structure.
Formation and localities—Upper portion of the Pogonip Group, White Mountain, Goodwin Canon, and Fish Creek Mountains, Eureka District, Nevada.
BRACHIOPODA. Genus OBOLELLA Billings, Obolella ? ambigua, n. sp. Plate i, fig. 2a, b, ©.
Shell of medium size for the genus as now known, ovate, moderately convex; surface lamellose; shell caleareous. Ventral valve ovate, broadly
68 PALEONTOLOGY OF THE EUREKA DISTRICT.
rounded in front, widest one-third the length from the front, thence round- ing and narrowing gently to the beak, which is rather broadly rounded ; area unknown. ‘The dorsal valve is transversely ovate to subcircular, beak emarginate.
The interior of the ventral valve is unknown; that of the dorsal valve shows a central median depression divided centrally by a narrow raised line; towards the beak the depression is broader, narrowing midway, and dividing before reaching the center of the shell; a large muscular scar occurs each side of the central depression, and also a depressed line a little beyond them that runs out obliquely from the beak. There appears to be a muscular scar on each side of the center of the median depression just at its bifurcation. No other scars could be detected.
In external form and character this species is allied to Obolella gemma, and 0. chromatica of Billings. The arrangement of the muscular scars in the smaller valve is peculiar and the shell is also thinner than in the above species.
The generic reference is made with a query as in comparing it with the dorsal valve of Obolella sagittalis Salter, as illustrated by Davidson, we find a marked difference and would scarcely refer the two to the same genus. In a comparison with American species the reference would be to Obolella, as the interior of the dorsal valve has not been given in the typical species, and that of Obolella polita has little if any more than a strong specific varia- tion from that of O.? ambigua.
Mr. Davidson, in speaking of the species arranged under Obolella, says that the diagnosis of the genus will require modification before it can com- prise O. chromatica (the type) O.? polita, O.? Salteri, O. desiderata, ete. From our limited study and comparisons it does not appear that all these can be united under one genus—0O. polita and O. ambigua presenting one type, O. gemma and O. desquamata another, and O. sagittalis Salter, still another among the species now referred to the genus.
Formation and locality—Pogonip Group. Base of Silurian. East slope of ridge east of the Hamburg mine, Eureka District, Nevada.
FOSSILS OF THE LOWER SILURIAN. 69
Genus SCHIZAMBON, n. g.
Shell ovate or oblong oval, inequivalve; valves inarticulate; larger or ventral valve most convex, with a short obtuse beak at the cardinal margin. Foramen oblong and opening on the summit of the valve, no area nor delti- dium; cardinal edge thin; smaller or dorsal valve nearly as: convex as the larger, slightly flattened along the median line.
Structure caleareo-corneous, consisting of a nacreous outer layer with a closely attached inner calcareous layer. Both layers are thought to be punctured by scattered tubule. Surface smooth or with distinct lines of growth and scattered spines apparently on the outer edges of the laminz or lines of growth.
The interior of the larger valve shows the oblong foramen in a slight elongate depression and a pair of muscular scars just in front of it on each side of a slight longitudinal depression; from near the beak on each side of the foramen, a shallow sharply defined depression extends obliquely out- ward. No other markings were observed. In the interior of the dorsal valve a pair of anterior central muscular scars terminate their path of ad- vance from the beak, a slight rounded ridge rising on the central line; pos. terior to these a larger pair occur, and still beyond and more posterior a third pair, a narrow rounded ridge extending obliquely down from the beak on each side between the central and lateral scars.
The above description is based on a large number of specimens. Nu- merous interiors of the valves occur owing to the rough outer surface cling- ing to the fine arenaceous limestone matrix. In the interiors little pits occur scattered irregularly over the surface, and on the outside similar pits are seen. It is difficult to determine whether these communicate with each other. Judging from their appearance and also from a cross-section of the shell that shows minute tubule nearly through the shell, we are inclined to consider the shell as punctate. The little, short spines of the outer surface have the form of those on Siphonotreta; whether they are hollow or not has not been determined.
The most nearly related genera are Acrothele and Acrotreta. It is unlike Acrothele in the structure of its shell, in the position of the opening
70 PALEONTOLOGY OF THE EUREKA DISTRICT.
on its ventral valve with relation to the apex of the valve and in the absence of any indication of a false area. The general facies of the shell also suggests another generic group. Its affinity with Acrotreta consists in the presence of the three pairs of muscular scars in the smaller valves and in the perforate larger valve. The surface structure and general form closely ally it to Siphonotreta, and I would refer Siphonotreta fissa Kutorga, to this genus, as in all external characters it is almost specifically related to Schizambon typicalis.
Schizambon typicalis, n. sp. Plate i, figs. 3a-d.
Shell small, longitudinally ovate; length and breadth nearly the same; front and side margins broadly rounded; posterior margin of the ventral valve slightly acuminate, of the dorsal valve broadly rounded, except a very slight projection at the center. The ventral valve has a small, oblong foramen near the apex, with a gradually narrowing depression extending to the posterior extremity. Both valves are slightly convex, the ventral one the more so. Surface marked by lamellose concentric raised lines, bordered with fine spines on the outer portions of the shell. Towards the beak numerous fine concentric strize appear.
The shells consist of an outer nacreous layer, with an exceedingly thin inner calcareous layer closely attached to it. As has been mentioned under the generic description, the shell appears to be punctate. In many instances scarcely a pit is seen on the inside of the shell, while in others they are scattered quite thickly over the surface. The largest specimens obtained measured 5™™ in length by 4.5™™ in breadth.
In the ventral valve, fig. 3, the margin of the siphonal opening is slightly elevated and extends quite to the beak, leaving a triangular, elon- gate, narrow depression behind the opening. Starting near the beak and running obliquely outward a slightly-depressed, narrow, smooth line shows the advance of a muscular scar; between this and the siphonal opening a smooth space intervenes, in the front of which a pair of muscular scars can be detected. A slight depression extends forward in advance of the siphonal
opening.
FOSSILS OF THE LOWER SILURIAN. 71
The dorsal valve, fig. 3b, shows a narrow median ridge with a pair of minute, elongate, oval scars at its front termination (a, @); posterior to these and between the central ridge and a low ridge extending from the beak obliquely outward and forward a larger, reniform sear occurs on each side (p, @); outside of the narrow lateral ridges and on the posterior lateral por- tion of the shell another minute scar is seen on each side (a,d). None of the.specimens show a scar beneath the beak.
A comparison with the figures of Siphonotreta fissa Kutorga® shows a strong generic relation, judging from the external characters; specifically they have several points in common.
The species occurs in the passage beds at the base of the Pogonip Group in the same band of layers carrying Acrotreta gemma, Lingulepis, Discina, Orthis, Camarella calcifera, Ptychoparia Oweni, Dicellocephalus Jinalis, Illenurus Eurekensis, Amphion, Barrandia McCoyi, ete.
Formation and locality—Lower portion of Pogonip Group. East slope of ridge east of the Hamburg mine Canon, Eureka District, Nevada.
Genus STROPHOMENA Rafinesque.
Strophomena Nemea, H. & W.
Strophomena Nemea, Hall & Whitfield, 1877. Geol. Expl. Fortieth Par., vol. iv, p. 233, pl. i, fig. 15.
This species occurs in the upper beds of the Pogonip Group at Lone Mountain, 18 miles northwest of Eureka, at the same horizon on McCoy’s Ridge, and a little lower down in the strata on the west slope of Secret Canton road Canon, Eureka District, Nevada.
The original type of the species is from Pogonip Mountain, White Pine District, Nevada.
6Uber die Brachiopoden-Familic der Siphonotretwx. Verhandl. der Russ. Kais. Mineral. Gesell- schaft, 1848, p. 250, pl. vii, figs. 5a-c.
72 PALEONTOLOGY OF THE EUREKA DISTRIOT.
Genus ORTHIS Dalman.
Orthis perveta Conrad. Plate xi, figs. 3, 3a, b.
Orthis perveta Conrad, 1843. Proc. Acad. Nat. Sci. Phila., vol. i, p. 333. Hall, 1852. Pal. New York, vol. i, p. 120, pl. xxxii, figs. 5a-c. Ibid. Geology of Wisconsin, p. 42, figs. 7a—d, 1862. Billings, 1863. Geol. Canada, p. 130, figs. 57 a-f.
This species is quite abundant in the upper beds of the Pogonip Group at Lone Mountain, and it also ranges through nearly 1,000 feet of the lime- stone of White Mountain, and is found at about the same horizon on the eastern slope of the ridge east of the Hamburg mine, as in the lower beds of White Mountain. .
A direct comparison of the Nevada specimens with the types of the species in the American Museum collections show their specific identity, and also that similar variations occur in examples from the widely-separated_ localities. In Wisconsin it is found in the Trenton limestone, and in Canada Mr. Billings identified it from the Chazy limestone.
A small but quite perfect specimen is illustrated. Owing to the partial exfoliation of the shell, the radiating strize are not as strong as on the unin- jured surface.
In the expedition of 1882 this species was found in the upper part of the Pogonip Group, on Pogonip Ridge, White Pine District, Nevada.
Orthis testudinaria, Dalman. Plate xi, figs. 10, 10a.
Orthis testudinaria Dalman, 1827. Vet. Acad. Hand., Stockholm, p. 115.
Orthis testudinaria Conrad, 1839. Emmons, 1842; Hall, 1852. Pal. N. Y., vol.i, p. 117, pl. 32, figs. La-l. Whitfield, Geol. of Wisconsin, vol. iv, p. 258, pl. xii, figs. By t, 1883,
See Davidson’s Monograph British Silurian Brachiopoda.
After comparing our specimens with those from New York, Ohio, and Wisconsin, we are unable to discover any differences of specific value be- tween them, although the eastern forms are from the Trenton Group=Tren- ton limestone and Hudson River formations, and the Eureka specimens
FOSSILS OF THE LOWER SILURIAN. {(53
from the horizon of the Chazy limestone and Calciferous sand-rock of the New York series. This identification and reference gives a greater vertical and geographic range to a species already distinguished for its wide dis- tribution. In England it ranges from the Llandeilo into the Lower Lland- overy, and it is also known in Ireland, Scotland, and Sweden.
Formation and localities. —Pogonip Group, summit of White Mountain, and about 1,000 feet below that horizon on east slope of ridge east of the Hamburg mine, Eureka District, Nevada, and at the same horizon on the north end of Pogonip Ridge, White Pine District, Nevada.
Orthis Hamburgensis, n. sp. Plate xi, figs. 5, 5a.
Shell small, suborbicular in outline, plano-convex; hinge line a little shorter than the greatest breadth of the valves. Dorsal valve moderately ‘convex, most elevated a little behind the center, along a slight ridge formed by two or three strong, slightly-raised strize; beak small, depressed about half-way down to the cardinal margin. Ventral valve depressed, slightly convex, mesial depression well defined from the beak to the front margin.
Surface of both valves marked by from 12 to 18 strong angular striz, which increase by bifurcation or intercalation towards the margin.
This species is represented by many separate valves, but none show the area of either valve. It is allied to O. testudinaria, but differs essentially in the surface ornamentation, which is more like that of O. plicatella in the fissi- costate character of the striz. A comparison with the adult shells of O. pli- catella and O. fissicosta shows that their surface characters are strongly devel- oped in O. Hamburgensis, while in the young shells of the same species of the size of the latter these features are not present.
Formation and localities —Central part of Pogonip Group, on the east slope of the ridge east of the Hamburg ridge; ‘on the east slope of the second ridge southeast of the Jackson mine, and also on the second ridge east of Secret Cation, Eureka District, Nevada.
74 PALEONTOLOGY OF THE EUREKA DISTRICT.
Orthis Lonensis, n. sp.
Plate xi, figs. 6, 6a.
Shell of medium size, transversely semi-oval, width and length as 4 to 3; hinge line about equal to the greatest breadth of the valves.
Ventral valve elevated, convex; the greatest convexity a little behind the middle on each side of a shallow, broad mesial sinus; beak small, not projecting backward; area high at the beak, sloping rapidly to the lateral margins; slightly arched, and standing at nearly right angles to the plane of the valve; foramen a little higher than broad, with its apex extending to the termination of the beak. Dorsal valve unknown.
Surface ornamented by distinct radiating strize that increase by inter- calation, and curve gradually outward to the postero-lateral margins.
This species belongs to that group of Orthis, of which O. occidentalis is a type, and appears to be specifically distinct from any described species.
Formation and locality.—Pogonip Group, upper beds, Lone Mountain, 18 miles northwest of Eureka, Nevada
Orthis tricenaria, Conrad. Plate xi, figs. 4, 4a.
Orthis tricenaria Conrad, 1843. Proc. Acad. Nat. Sci., vol. i, p. 333.
Orthis tricenaria Hall, 1852. Pal. N. Y., vol. i, p. 121, pl. xxxi, figs. 8a, ec. Ibid., Geol. Surv. Wisconsin, vol. i, p. 42, figs. 8-11, 1862.
Orthis tricenaria Billings, 1863. Geol. Canada, p. 167, figs. 151 a, b.
An examination of a good series of specimens of this species shows that it varies a little in the number and strength of the surface striz in both the young and old shells, the variation extending from the average number of 28 to 30, to 16 as the minimum and 385 as the maximum; with this in view, the specimens from the Pogonip Group (upper beds, at Lone Mount- ain and Surprise Peak) cannot well be specifically separated from those of Wisconsin and New York. The general form of the shell is the same, and the number of radii varies from 16 to 30. Some of the examples are almost typical forms of Orthis costalis, of the Chazy limestone of New York, and a comparison of specimens shows the two species to be closely allied. It may be considered that the Nevada form is a variety of O. triceuaria, and worthy
FOSSILS OF THE LOWER SILURIAN. 15
of a distinct name, but until there is more evidence than at present, we pre- fer to recognize it as coming within the limits of the eastern species.
Formation and locality—Pogonip Group at Lone Mountain, 18 miles northwest of Eureka, and on Surprise Peak, Eureka District, Nevada. It also occurs at the same horizon on Pogonip Ridge, White Pine District, Nevada.
Genus STREPTORHYNCHUS King. Streptorhynchus minor, n. sp. Plate xi, fig. 9.
Shell small, transverse, semi-oval; hinge line fully equaling the greatest breadth; lateral extremities nearly rectangular.
Ventral valve moderately convex along each side of a rather broad mesial depression, extending from the umbo to the front margin; postero- lateral regions flattened within the margin; beak minute and scarcely to be distinguished from the cardinal margin. Dorsal valve unknown.
Surface of ventral valve ornamented with rather fine radiating striz that increase by intercalation towards the front margin.
Length of specimen, 6"; breadth, 11"; convexity, about 1.25™™.
This little shell presents the characters of a resupinate Strophomena, and is therefore placed under the genus Streptorhynchus. It may be com- pared with young shells of Streptorhynchus sinuatus Emmons (Pal. Ohio, vol. 1, p. 87, pl. v, figs. 5 a-f, 1873), but it appears to be a distinct species from any described.
Formation and locality.—Pogonip Group, upper beds, at Lone Mountain, 18 miles northwest of Kureka, Nevada.
Genus TRIPLESIA Hall. Triplesia calcifera Billings. Plate xi, figs. 7, 8. Camerella calcifera Billings, 1861. Canadian Nat. and Geol., vol. vi, p. 318, figs. 3 a-e. Geol. Canada, p. 231, figs. 247 a-c, 1863. Pal. Foss., vol. i, p. 220, 1865.
There is considerable variation among the specimens referred to this species in the collection, and two species appear to be indicated. In one the mesial depression is shallow with broadly-rounded sides, and in the other it is deeper and more angular. In the dorsal valves the variation is
76 PALEONTOLOGY OF THE EUREKA DISTRICT.
quite as great, but with more gradations between the valves with a scarcely perceptible median fold and those where the fold is the prominent feature.
The figure of the ventral valve, fig. 7, is of the type of that given by the author of the species, and that of the dorsal valve, fig. 8, is not very dissimilar, although representing what may prove to be a distinct species.
Formation and localities —Lower portion of the Pogonip Group, and upward about 1,000 feet on the east slope of ridge east of the Hamburg mine; on the second ridge southeast of the Jackson mine, also northeast of Adams Hill; on the ridge southeast from the Wood Cone; at the south- west end of McCoy’s Ridge, and on the west side of Goodwin Canon, Eureka District, Nevada.
LAMELLIBRANCHIATA. Genus TELLINOMYA Hall. Tellinomya contracta Salter (?) Plate xi, fig. 15, 15 a. Ctenodonta contracta Salter, 1859. Canadian Organic Remains, Dec., i, p. 37, pl. viii, figs. 4, 5.
It is not improbable that the Nevada shell is specifically unlike T. contracta, but with the specimens at hand it is difficult to determine the differences if they exist. Mr. Billings has described a closely allied form from the Quebec series of Newfoundland, but our species is more nearly related to Salter’s species from the Trenton limestone of Canada, to which, for the present, it is referred.
Formation and locality—Upper part of Pogonip Group, Fish Creek Mountains, Eureka District, Nevada. It also occurs at the same horizon on - Pogonip Ridge, White Pine District, Nevada.
Tellinomya ? Hamburgensis 0. sp.
Plate xi, figs. 1, la. Shell small, thin, convex; rounded subrhomboidal in outline with the height and width subequal; beak elevated, incurved, and raised above the hinge line anterior to the center of the shell.
FOSSILS OF THE LOWER SILURIAN. OU
The surface presents a smooth, glistening appearance, and is marked by fine concentric stri and very fine, often scarcely perceptible radiating strie. This surface gives to fragments of the shell the character of some of the Linguloid shells.
The species belongs, by its general form, to the group of which 7. (Ctenodonta) varicosa Salter (Mem. Geol. Surv. Gt. Brit., vol. iii, p. 345) and T. (C_) astarteformis Salter (Can. Org. Remains, dec. 1, p. 39, pl. viii, fig. 7) are the types; specifically it is distinct.
Formation and locality—Upper part of Pogonip Group. Last slope of ridge east of the Hamburg Ridge, Eureka District, Nevada.
Genus MODIOLOPSIS Hall. Modiolopsis occidens, n. sp. Plate i, fig. 5; pl. xi, figs. 14, 14a.
Shell small, elongate, ovate in outline; broadest at the posterior half, contracting to about two-thirds the greatest width at the beaks; hinge-line nearly straight and a little more than half as long as the shell posterior to the beaks; posterior margin slightly convex and sloping obliquely from the extremity of the hinge-line to the rounded posterior end of the shell; the basal line curves downward, and then with a slight sinuosity, opposite the beak, extends nearly straight to the somewhat narrow, sharply rounded, anterior end; beak small, scarcely extending above the hinge-line, and sit- uated within the anterior third of the shell. The surface is moderately convex, most prominent along the posterior umbonal ridge, which is rather broadly rounded; umbonal slope abrupt and slightly convex. A broad, obscure mesial depression is shown on the lower part of the anterior half of the shell that does not extend up to the beak.
Anterior muscular scar of medium size and well defined; posterior scar, pallial line, and exterior surface markings unknown.
This species is related to Modiolopsis mytiloides Hall (Pal. N. Y., vol. i, p. 157, pl. xxxv, figs. 4a, 6) in its general outline, but differs in its less elongate form and in its position of its beaks.
Formation and localities.—Pogonip Group, upper portion, Fish Creek
78 PALEONTOLOGY OF THE EUREKA DISTRICT.
Mountains, Eureka District, and beneath the white quartzite at Lone Moun- tain, 18 miles northwest of Eureka, Nevada. It also occurs at the same horizon on Pogonip Ridge, White Pine District, Nevada.
Modiolopsis Pogonipensis, n. sp. Plate i, fig. 6; pl. xi, fig. 13.
Shell quite small, ovate in outline, broadest at the posterior third; hinge- line two-thirds the length of the shell posterior to the beak; posterior mar- gin very oblique, slightly convex, and terminating at the somewhat sharply rounded posterior extremity of the shell; basal margin slightly curved, almost straight along the center; anterior end of the shell broadly rounded. General surface moderately convex, most prominent along the rounded posterior umbonal ridge; the beak is strong and rises a little above the hinge-line; anterior muscular sear distinct; posterior scar unknown.
Surface smooth or marked by broad inconspicuous lines of growth.
Formation and localities—Same as preceding species.
GASTEROPODA.
Genus RAPHISTOMA Hall. Raphistoma Nasoni Hall. Plate xi, figs. 21, 21a.
Pleurotomaria nasoni Hall (?) 1861. Rep. Prog. Geol. Surv. Wisconsin, pam., p. 34. Raphistoma (Pleurotomaria) nasoni Hall, 1862. Geol. of Wisconsin, vol. i, p. 39, fig. 2. Raphistoma Nasoni Whitfield, 1883. Geol. of Wisconsin, vol. iv, p. 215, pl. vi, figs. 2-3.
The Nevada shell is a closely allied or representative species of this, and in its condition as a cast it is impossible to give any good specific dif- ferences between them. It might be considered a distinct form from its occurring at so distant a locality and at a lower geologic horizon, but these circumstances are largely negatived by the facts that well-character- ized Devonian species occur in New York and Nevada and at different relative horizons, as will be shown under the head of the Devonian fossils; and species heretofore considered as belonging to the Trenton horizon have been identified in the Pogonip limestone, e. g., Orthis testudinaria, O. trice-
FOSSILS OF THE LOWER SILURIAN. 19
naria, ete. Under such circumstances we prefer to refer all such species to described forms unless they show good, specific differences, or a dif- ference in their geologic horizon that renders their occurrence extremely improbable.
Formation and locality—About 1,000 feet down in the Pogonip Group, north slope of White Mountain, Eureka District, Nevada.
Genus MURCHISONIA D’Archiae and De Verneuil.
Murchisonia Milleri Hall? Plate i, figs. 12, 124, b. Murchisonia bicincta Hall, 1847. Pal. N. Y., vol. i, p. 177, pl. xxxviii, figs. 5, 5 a-h. bicineta Salter, 1858. Canadian Organie Remains, dec. i, p. 19, pl. iv, figs. 5, 6, 7. bicincta M. & W. ?, 1868. Geol. Surv. Illinois, vol. iii, p. 317, pl. iii, fig 4. Milleri Hall, 1877. Cat. Amer. Pal. Fossils, Miller, p. 244.
Not Murchisonia bicincta McCoy, 1844. Syn. Sil. Foss. Ireland. p. 16.
On comparing specimens of Murchisonia Milleri, from Middleville, New York the typical locality of the species, with the Nevada shell, certain differ- ences appear that would serve to separate the form from Nevada as a distinct species from J/. Milleri if the range of variation in the specimens from the two localities did not afford examples from each that are specifi- cally identical. As compared with the majority of the New York and Canadian specimens, the Nevada shell is more depressed, the aperture less elongate, and the carina above and below the peripheral carina less strongly marked, differences, however, that are not apparent when comparing with some shells from the typical locality at Middleville; with this in view, and the fact that a certain range of variation may be allowed for changes pro- duced during the geographic distribution of the species, I think we are justified in identifying the Nevada shell with MW. Milleri. It is associated with common Trenton limestone fossils, Orthis tricenaria, O. perveta, Raph-
istoma Nasoni, Illenus crassicauda, and other species indicating the Trenton fauna.
Formation and locality—Lower Silurian, near the summit of the Pogo- nip limestone of Pegonip Ridge, White Pine District, Nevada.
80 PALEONTOLOGY OF THE EUREKA DISTRICT.
Casts of two species of Murchisonia occur in the upper beds of the Pogonip Group of the Eureka District. One is slender, elongate, and formed of many whorls, resembling the eastern species Murchisonia gracilis Hall (Pal. N. Y., vol. i, p. 181, pl. xxxix, figs. 4a-c); the other is a much larger, stronger species, more like Murchisonia bellicincta of the 'Trenton lime- stone of New York. ‘The specific relations of either are not determined.
Genus PLEUROTOMARIA Defrance. Pleurotomaria Lonensis, n. sp.
Plate xi, fig. 22.
Shell rather small, depressed conical; the apical angle about 110°; volutions three or four, each flattened above to within a short distance of the sharp mesial angle, where a narrow groove extends around on the lower volution, becoming obsolete on the second volution; suture in the cast strong and channeled; lower side of body volution sloping quite rapidly in from the mesial angle, a little concave just within the angle, and then gently con- vex to the umbilicus, which is rather small. Aperture rhombic-subquadrate, as far as can be determined from the form of the body volution.
Surface unknown except by the presence of rather strong revolving lines on the lower side of the body volution.
This species is distinct from any known to us.
At the same horizon and localities there is another species that may be referred to this genus; it isa larger and more robust form, having the whorls more convex above, flattened below on the body volution, and an acutely an- gular periphery at the union of the upper slope of the whorls and the base; this latter feature also occurs in P. Lonensis.
Formation and localities—Upper beds of the Pogonip Group, Lone Mountain, 18 miles northwest of Eureka; at the south end of Fish Creek Mountain exposure of the Pogonip, and on east slope of ridge east of Ham- burg mine, Eureka District, Nevada.
On the north end of Pogonip Ridge, White Pine District, Nevada, this species is abundant and reaches a larger size than at Lone Mountain.
FOSSILS OF THE LOWER SILURIAN. 81
Genus HELICOTOMA Salter.
Helicotoma sp.?
The specimens illustrating this species are badly crushed, but there is sufficient form preserved to show that it is allied to H. planulata Salter (Cana- dian Organic Remains, dee. i, p. 14, pl. ii, figs. 5-7) and H. uniangulata Hall (Pal. N. Y., vol. i, p. 179, pl. xxxviii, fig. 8). It is interesting from its occur- rence at an horizon between those of the two species mentioned. ‘The first being from the Calciferous sandstone of New York, and the second from the Trenton limestone of Canada.
Formation and localities —Upper beds of Pogonip Group. Lone Moun- tain, 18 miles northwest of Eureka, and summit of White Mountain, Eureka District, Nevada.
Genus MACLUREA Le Sueur. Maclurea annulata, n. sp.
Plate xi, figs. 19, 19 a.
Shell quite small, subdiscoidal, varying from 10™" to 12™™ in the greatest diameter; spire depressed so as to form a false umbilicus; lower side flattened, the whorls all on one plane. Volutions about two, increas- ing rapidly in size with the increase in growth of the shell; flattened on the under side, rounded or subangular on the lower periphery; the sides rather steep; transverse section of the outer volution semiovate.
Surface of the shell somewhat strongly annulated, the annulations on the outer volution having a breadth of about 1.5.
Casts of this species show the shell to have been quite thick, and a fragment of the outer volution is near 0.75™™ in thickness. The annulations and the constrictions between are strong, but owing to the thickness of the shell no perceptible traces of them are preserved on the internal cast.
The cast is more angular on the lower outer margin than on the upper margin; it bears a strong resemblance to M. minima H. and W. (Geol. Expl. Fortieth Par., vol iv, p. 235, pl. i, figs. 17-19), in this condition, but varies in the greater depth of the whorls and the more rapidly increasing size of the inner whorls of M. minima.
6cDW
82 PALEONTOLOGY OF THE EUREKA DISTRICT.
Formation and localities—Strata of the Pogonip Group, north slope of White Mountain, 500 feet below the summit; east slope of ridge east of the Hamburg mine, Eureka District, Nevada. The species also occurs at the same horizon on Pogonip Ridge, White Pine District, Nevada.
Maclurea subannulata, n. sp. Plate xi, figs. 18, 18 a-b.
Shell about twice the size of the preceding species and presenting all its essential features of a flat lower surface and deeply umbilicate or depressed upper side. It differs in the more rapidly increasing size of the volutions, their more elongate semioval section, more rounded periphery, and in the cast being obscurely annulated but in a reverse manner from what would be the case if the annulations of the outer shell of MZ. annulata were present on the cast; the constrictions, instead of being narrow, are quite broad and the annulations narrow.
Formation and locality—Pogonip Group, north slope of White Mountain, Eureka District, Nevada.
Maclurea carinata, n. sp. Plate xi, figs. 20, 20a.
Shell small, general form thick, discoidal; greatest diameter, 20"; height of outer whorl, 6™"; spire depressed to form a broad, shallow, um- bilical-like area; lower side nearly flat, or with a slight umbilical depression of the inner whorl; volutions about three, increasing very regularly in size with the growth of the shell; slightly convex on the lower side, terminating in a decided carina on the periphery, where it unites with the slope of the side; the sides of the whorl are steep, and equal in depth to the width, the carina at the lower outer margin of the inner whorls resting in the sutures of the umbilical side.
Surface of the lower sides of the whorls marked by numerous strong strize that arch across the whorl and forward over the carina; their course on the upper side has not been observed.
FOSSILS OF THE LOWER SILURIAN. 83
The cast of the outer whorl is round-oval in outline, the shell being thick and forming the carina seen on the outer surface. The presence of the basal carina distinguishes this species from any described form.
Formation and locality—Upper beds of the Pogonip Group at Lone Mountain, 18 miles northwest of Eureka, Nevada.
Interior casts of a species allied to this, and it may be the same, occur on White Mountain and the lower eastern slope of the ridge east of the Ham- burg mine, and at the same horizon on the Fish Creek mountains, Kureka District, Nevada.
Maclurea, sp. ?
Associated with the preceding at Lone Mountain there is a cast of a much larger and unusually flattened or compressed species. Owing to a doubt of this being its natural form, it was omitted in selecting specimens for illustration. In general form it is not unlike M. acuminata Billings (Pal. Foss., vol. i, p. 241, fig. 225, 1865), except that it is very shallow, not one-half the depth of the latter.
Genus METOPTOMA Phillips. Metoptoma Phillipsi, n. sp. Plate i, figs. 4, 4a.
General form of shell depressed conical; outline of base broadly elliptical to ovate; apex elevated and situated a little behind the anterior margin; sides gently convex or sloping, almost straight from the apex to the lateral margins; anterior slope from the apex to the margin slightly con- cave; posterior slope, from the apex to the posterior margin, broadly convex.
Surface marked by fine concentric strize of growth, with a few stronger strie, or lines, at irregular intervals.
Dimensions: greater diameter of base of large specimen, 23™™; lesser diameter, 17™™; height of apex above base, 10™. A small specimen gives 8™" and 6™™ for the two diameters of the base, and 8™ as the height, show- ing that the relative proportions remain nearly the same in the young shells.
I know of no closely related American or European species. Mr. Bil- lings has described a number of species from the Quebec and Trenton
84 PALEONTOLOGY OF THE EUREKA DISTRICT.
Groups of Canada, but owing to the few salient characters to notice in a description, and the entire lack of illustration, it is impossible to make spe- cific identifications. The most nearly related species with which I am acquainted are Metoptoma Trentonensis Billings (Pal. Foss., vol.i, p. 40, fig. 41, 1865), and M. perovalis Whitfield (Geol. Surv. Wis., vol. iv, p. 211, pl. y, figs. 13, 14, 1883), from the Trenton limestone.
Formation and locality—Lower Silurian, near the summit of the Pogonip limestone, Pogonip Ridge, Eureka District, Nevada.
Metoptoma ? analoga, n. sp. Plate i, figs. 11, lla.
Shell subconical, patelliform; outline of base broadly elliptical; apex elevated, subcentral, and bending slightly to one side.
Surface marked by slightly defined undulations of growth.
Dimensions.—Base, greater diameter, 11"; lesser diameter, 9™™; height of apex above base, 6™.
This somewhat irregular shell occurs at the same geologic horizon as M. Phillipsi, but not in the same stratum of rock. It is a well-marked species, approaching the common form of a true patella more than the forms usually referred to Metoptoma. As with all generic references of the Pale- ozoic patelloid shells, when the interior muscular scars are unknown, it is more or less arbitrary.
Formation and locality —Lower Silurian, near the summit of the Pogonip limestone, Pogonip Ridge, Eureka District, Nevada.
Genus CYRTOLITES Conrad. Cyrtolites sinuatus H. & W.
Cyrtolites sinuatus Hall & Whitfield, 1877. Geol. Expl. Fortieth Par., vol. iv, p. 237, pl. i, figs. 23, 24. ;
The type of this species is from the Pogonip limestone of Pogonip Mountain, in the White Pine Mining District, Nevada. It also occurs in the upper beds of the same group at Lone Mountain, 18 miles northwest of Eureka, Nevada.
FOSSILS OF THE LOWER SILURIAN, 85
PTEROPODA. Genus COLEOPRION Sandberger. Coleoprion minuta, n. sp. Plate xi, figs. 17, 17a; pl. xii, fig. 21.
Minute, slender, elongate subcylindrical tubes; slightly curved, with a distinct angularity on the outer side, section subelliptical. Average length, 8™™ to 10™"; average diameter, 1.25™™ at smaller end to 2.25™™at larger end.
Surface marked by fine annulations, with very fine concentric stricz between, the latter perceptible only under favorable conditions. The annu- lations are narrow, rather sharp, and cross the inner side of the curvature of the tube transversely, bending obliquely backward on each side, and meet- ing at an angle on the slight ridge on the outer side.
This interesting little species is probably a true Coleoprion, although presenting some differences from the typical species; these, however, appear to be rather of specific than generic value.
M. Barrande describes one species from the Upper Silurian (tage E), and one from the Devonian, at which horizon all other species referred to the genus have been obtained. Its range is now extended down to the horizon of the Chazy limestone of the New York series, or the summit of the Pogonip Group of Nevada.
Formation and locality—Upper Pogonip limestone of Lone Mountain, 18 miles northwest of Hureka, Nevada, and at the same horizon on Pogo- nip Ridge, White Pine District, Nevada. :
Genus HYOLITHES LHichwald.
Hyolithes Vanuxemi, n. sp. Plate xi, figs. 16, 16 a, b.
Form, a slender, elongate, subtriangular tube, with the lateral margins rounded, gradually tapering from the base to an acute extremity. Trans- verse section semi-elliptical, almost flat on the ventral side, the lateral edges rounded or subtriangular. Ventral face nearly flat transversely and in-
86 PALEONTOLOGY OF THE EUREKA DISTRICT.
curved longitudinally; dorsal face strongly convex and obtusely angular along the center in some examples. Form of the aperture unknown.
Surface with fine transverse striz on the ventral and dorsal sides along the central portion of the tube; these were not observed towards the aper- ture.
Length of larger examples, 20"; greatest width, 2.75"; depth, 2™™.
This species is distinguished by its slender elongate form with the sub- triangular section from any described form known to me.
Formation and locality—Lower beds of the Pogonip Group, northeast of Adams Hill, Eureka District, Nevada.
CEPHALOPODA.
ORTHOCERATA. Plate xii, figs. 1, 1a-o, 2, and 3. Numerous fragments of Orthoceratites occur in the upper beds of the
Pogonip Group at Lone Mountain and the Fish Creek Mountains. From among them several well-defined species may be selected. 1. Endoceras proteiforme Hall? (Pal. N. Y., vol. i, p. 208, 1847) ; plate xii, figs. 1, 1a-c.
This is the most abundant, and is found at the principal exposures of the upper portion of the group, and the transverse sections (fig. 1a) are often seen. In fig. 1 the siphuncle with an inner tube is shown, and fig. 1c shows the annulations on the outer surface of the siphuncle.
2. Orthoceras multicameratum Hall? (Pal.N. Y., vol.i, p. 45, 1847); plate xii, fig. 3.
The fragment illustrated on plate xii, fig. 3, and also several not figured, shows a form closely allied to the species from the Birdseye limestone of New York; with the exception of the tube not converging as rapidly to- wards the apex the specific resemblance is very strong.
3. Orthoceras sp.? plate xii, fig. 2. An elongate form of the type of the preceding species. The material
representing it is so fragmentary that a specific identification is not at- tempted.
FOSSILS OF THE LOWER SILURIAN. 87
4. Endoceras multitubulatum Hall? (Pal.N. Y., vol.i, p.59, 1847).
Several elongate tubes filled in with smaller tubes, as in EZ. multitubula- tum, occur in the upper beds of the Fish Creek Mountain Pogonip, and simi- lar specimens were observed a little lower in the group at White Mountain. They belong to the same group of species as LZ. multitubulatum, but in the fragmentary condition of the specimens it is impossible to state that they are specifically identical with the Trenton species.
5. Orthoceras sp.? plate xii, fig. 1b.
This is a transverse section of a tube showing a peculiar siphuncle and inner tube. As the figure on the plate does not give the desired repre- sentation, figures are here introduced that show a slightly oblique section at each end of a tube 10" in length.
The inner tube (s) is subcentral with a broad extension (e) from one side nearly to the side of the tube next outside of it (a), 5, and on the opposite side a thin septum (c) projects towards the side of the tube. A longitudinal view of the tube (s) shows it to be straight and without annulations. Viewing the specimen as complete with the tubes (s) and (x), we find it to be closely allied to a section given of Orthoceras bonum by Barrande,’ but if the outer shell (0) belongs to the Dares Nevada shell and is not a fragment into which the tube (a) was drifted, then the peculiar section is not explained by any described species known
to me, as it would be much as is represented by the fig. 1b of plate xii, and be formed of three tubes, one within the other.
Future exploration and the discovery of more material will undoubt- edly afford the paleontologist the means of identifying this and several other species now recognized by fragments too imperfect for description but still specifically distinct from each other and the species we have mentioned. The fragmentary remains now before us, however, with the associated Brachiopods, Lamellibranchs, and Gasteropods serve the present purpose of the geologist, as they indicate the passage from the Pogonip (Quebec) to _ the Trenton fauna.
7 Syst. Sil. Bohéme, vol. ii, pl. ccxlvii, fig. 11.
88 PALEONTOLOGY OF THE EUREKA DISTRICT.
CRUSTACEA.
Genus LEPERDITIA Roualt. Leperditia bivia White.
Leperditia bivia White, 1874. Expl. and Surv. West 100th Merid. Prelim. Notice Invert. Foss., p. 11; ibid., vol. iv, pt. 1, p. 58, pl. iii, figs. 7 a-d, 1875.
This species is very abundant in the upper beds of the Pogonip Group, at Lone Mountain, 18 miles northwest of Eureka, White Mountain, and the Fish Creek Mountains, Eureka District, Nevada.
The original type specimens were from the Schell Creek Range of Nevada.
Associated with this species we find two smaller species not unlike some varieties of DL. Canadensis (Can. Organic Remains, dee. iii, p. 92, pl. xi, figs. 6, 7, 9, 10, 1858), the determination and illustration of which is left for fu- ture study.
Genus BEYRICHIA McCoy.
Beyrichia, sp.?
This is an interesting species, as it is of the type of B. regularis Em- mons (Amer. Geol., pt. 2, p. 219, 1858), of the Hudson River Group of Ohio.
Owing to the imperfect condition of the specimens its further identifi- cation is delayed in the hope of obtaining better material. It is associated with Leperditia bivia, at White Mountain, Eureka District, Nevada.
Genus PLUMULITES Barrande.
The presence of this rare genus in American strata, west of Ohio, has not hitherto been recorded, and now we have but a single plate to show it. This is triangular in its general form, with the basal margin sigmoidal and the surface ornamented with the characteristic lines parallel to the sigmoidal margin. It occurs in the lower portion of the Pogonip Group, on the southwest end of McCoy’s Ridge, Eureka District, Nevada.
FOSSILS OF THE LOWER SILURIAN. 89
PCECILOPODA.
Genus DICELLOCEPHALUS Owen. Dicellocephalus finalis, n. sp. Plate xii, figs. 12, 12a, b.
Form of glabella and fixed cheeks united, very irregular; front broad, rapidly contracting before and expanding at the eyelobes to contract again back of them. Glabella of about, the same width at the base and in front, expanding, on the posterior half, to the border of the palpebral lobes; gen- eral surface quite convex on the anterior half and moderately so farther back, marked by three pairs of glabellar furrows; the anterior pair slightly impressed and short, situated opposite the anterior end of the eyelobes; the median pair more strongly impressed and directed obliquely inward about one-fourth the distance across from side to side; directly back of this pair the margin curves outward around a curved expansion of the glabella, and within this the posterior pair of furrows are impressed, similar to the median pair, but not reaching the outer margin; this gives the posterior portion of the glabella a very peculiar aspect, unknown in any other species of the genus; occipital ring broad and flattened; occipital furrow narrow and well impressed; dorsal furrow distinct, but very shallow; fixed cheeks hardly more than a line, except where they join the broad frontal limb; palpebral lobes long and narrow; postero-lateral limbs narrow and extended laterally; frontal limb of moderate length, gently concave, and bordered by a strong rounded margin, the anterior edge of which is broadly rounded up to a very obtuse angle at the center.
Thorax known only by fragments of the segments associated with the head parts. These show the median lobe to have been moderately convex and the lateral lobes less so; the pleure are straight or slightly curved two- thirds the way out, and then curved backward on the free end; pleural groove strongly marked.
The associated pygidium is moderately convex, with a conical axial lobe crossed by three annulations, besides the long terminal one; lateral lobes
90 PALEONTOLOGY OF THE EUREKA DISTRICT.
indicating four coalesced segments, marked by pleural grooves and termi- nating in points that give a digitated margin to the pygidium.
Surface apparently smooth.
As all of these parts occur at one horizon and in the same layer, and no other large trilobite is associated with them, they undoubtedly belong to one species.
Formation and localities—In the lower portion of the Pogonip Group, on the east slope of the ridge next east of the Hamburg Ridge, Eureka District, Nevada.
Dicellocephalus inexpectans, n. sp.
Plate i, fig. 10.
Glabella quadrangular, moderately convex, lateral margins parallel, broadly rounded in front; surface marked by two pairs of slightly im- pressed glabellar furrows directed obliquely inward and backward; the occipital ring is of medium width, and the occipital furrow distinctly but not deeply marked; dorsal furrows clearly defined at the sides and front of the glabella; fixed cheeks very narrow, sloping rapidly away before and behind the palpebral lobe; palpebral lobes prominent and of medium size; frontal limb rather long and well extended laterally; a number of raised lines radiate from the front of the glabella to the frontal margin; frontal margin narrow, rounded; postero-lateral limbs unknown. The facial sutures pass very obligely inward from the anterior margin to the palpebral lobe, giving the front inclosed within them a campanulate form; curving around the palpebral lobes they pass outward on the postero-lateral limbs.
Surface finely granulose.
This species is associated in the same horizon with D. jinalis of this report. It was collected one year after the latter was described in MSS. It affords another illustration of a Cambrian type continuing into the Silu- rian and mingling with its fauna.
Formation and localities—Same as D. jfinalis.
FOSSILS OF THE LOWER SILURIAN. 91
Genus PTYCHOPARIA Corda.
Ptychoparia? annectans, n. sp. Plate xii, fig. 18.
Head very small, semicircular; postero-lateral angles unknown. Gla- bella moderately convex, length and width subequal, broadly rounded in front; marked by three pairs of furrows, the anterior pair scarcely per- ceptible, median and posterior pairs distinctly but not deeply impressed; occipital ring narrow, rounded, without a spine; occipital furrow well de- fined; dorsal furrow narrow, distinct, and extending with equal force in front of the glabella; fixed cheeks rather wide, sloping with a gentle con- vexity to the minute eyelobes and into the frontal limb; frontal limb con- vex, curving rapidly downward, and bordered by a rounded rim; postero- lateral limbs narrow, and extended quite a little distance laterally, marked by a narrow groove in the posterior margin.
Thorax and pygidium unknown.
This little species is closely allied to P. minutus (Sixteenth Ann. Rep. N. Y. State Cab. Nat. Hist., p. 150, pl. viii, figs. 5-7, 1861) of the Potsdam sandstone of New York, and the allied P. minor (Ibid, p. 149), from the same horizon in Wisconsin. It differs in the shorter glabella, absence of nuchal spine, and larger frontal limb. It is interesting as occurring in association with the preceding species, and as terminating the upper limit of the range of the genus in the Prospect Mountain section.
Formation and locality.—In the lower portion of the Pogonip Group on the east slope of the ridge next east of the Hamburg Ridge, Eureka Dis- trict, Nevada.
Genus BATHYURUS Billings.
Bathyurus? tuberculatug, n. sp. Plate xii, fig. 9. Glabella conical, strongly convex and elevated above the fixed cheeks;
occipital segment narrow, elevated on the posterior margin, and with a short spine projecting backward and a little upward from the center; occipital
92 PALEONTOLOGY OF THE EUREKA DISTRICT.
furrow rather broad and strongly impressed; fixed cheeks of average width, sloping upward from the strongly marked dorsal furrows to the eyelobes, falling away to the front and back; frontal limb curving abruptly down- ward to a strong rounded rim-like margin; postero-lateral limbs strongly marked by a furrow within the posterior margin.
Surface of glabella and fixed cheeks ornamented with pustules, finely granulose in the narrow interspaces.
This species is characterized by the pustulose surface of the head. No remains of the thorax or pygidium were observed in association with the head parts.
Formation and locality—Pogonip Group, on the ridge southwest of Wood Cone, Eureka District, Nevada, and at the same horizon on the north end of Pogonip Ridge, Eureka District, Nevada.
Bathyurus ? congeneris, n. sp.
Plate xii, fig. 8.
Compare Bathyurus ? serratus Meek, 1873. Sixth Ann. Rep. U.S. Geol. Sury. Terri- tories for the year 1872, p. 480.
General outline of glabella and fixed cheeks, exclusive of the postero- lataerl limbs, subquadrangular and rather strongly convex. Glabella ob- long, sides nearly parallel, and front rounded. Occipital ring of moderate width, and separated from the glabella by a narrow, well-impressed furrow; dorsal furrows narrow but well defined on the sides and in front of the gla- bella; fixed cheeks of medium width, somewhat depressed below the level of the glabella; frontal limb as a narrow, rounded rim; postero-lateral limbs, extended laterally and with a narrow furrow within the posterior margin.
Surface finely granulose.
An illustration is given of the pygidium associated with the glabella and fixed cheeks, plate xii, fig. 8 a.
This species is closely allied to Bathyurus ? serratus Meek, and Bathy- urus oblongus Billings (Pal. Foss., vol. i, p. 411, fig. 394, 1865), the chief difference between them being in the details of the frontal limb. They are
FOSSILS OF THE LOWER SILURIAN. 93
congeneric, but whether belonging to this genus or not it is difficult to deter- mine in the absence of the thorax and pygidium.
Formation and localities —Pogonip Group, on spur southwest of Wood Cone and below Bellevue Peak, Fish Creek Mountains, Kureka District,
Nevada.
Bathyurus ? simillimus, n. sp. Plate xii, fig. 11.
This species is closely related to the preceding and to B. oblongus Billings, (loc. cit. p. 92) in the form and convexity of the glabella and fixed cheeks; the frontal limb, however, is longer, curved more abruptly down- ward, and bordered by a rounded rim that has a distinct, very obtuse angu- larity in front.
The surface of the glabella is minutely granulose.
Formation and locality.—In the limestone of the Pogonip Group, on the north slope of White Mountain, about 500 feet from the summit of the mountain, Eureka District, Nevada.
The pygidium, illustrated by fig. 14 of plate xii, is of the same type as that upon which Mr. Billings founded the species Bathyurus caudatus (Pal. Foss., vol. i., p. 261, fig. 245, 1865), which occurs in the Quebec Group of Newfoundland. It undoubtedly belongs to a distinct species; its generic
relations are not recognized.
Genus CYPHASPIS Burmeister,
Cyphaspis? brevimarginatus, n. sp. Plate xii, fig. 10.
Glabella conical, strongly convex, marked by a pair of posterior gla- bellar furrows extending obliquely inward so as to nearly separate a small lobe at each postero-lateral angle; occipital segment broadest at the center narrowing towards the dorsal furrows; occipital furrow well defined; dorsal furrows distinctly impressed along the sides of the glabella; fixed cheeks rather narrow midway, widening in front; frontal limb as a scarcely per-
94 PALEONTOLOGY OF THE EUREKA DISTRICT.
ceptible, depressed, narrow rim in front of the glabella and fixed cheeks; postero-lateral limbs unknown.
Surface of glabella minutely granulose.
This species, although founded on a glabella but 4™™ in length, is clearly distinguished from any described form by its almost obsolete frontal margin and the conical outline of the glabella.
Formation and locality—Pogonip Group, on the eastern slope of ridge east of the Hamburg Ridge, Eureka District, Nevada.
Genus AMPHION Pander.
Amphion Nevadensis, n. sp. Plate xii, fig. 13.
Glabella subquadrangular, slightly convex, sides parallel, front broadly rounded; surface marked by three pairs of furrows, the two posterior pairs extending obliquely inward about one-third the entire distance across; anterior pair shorter and situated so far forward that the anterior lobe is somewhat irregularly rhomboidal in outline; occipital segment strong, flat- tened; occipital furrow narrow and like the dorsal furrows, deeply impressed; fixed cheeks known only in part; they are narrow in front, increasing in width at the eyelobes, and extending backward to the broad strong postero- lateral limbs; the latter are strongly marked by the continuation of the occipital groove within the posterior margin.
Surface granulose as far as can be determined from the specimens,
which owing to,exposure are somewhat imperfect.
Formation and localities —Pogonip Group, upper portion, on the south- east slope of Bellevue Peak, Fish Creek Mountains, Eureka District, Nevada; Amphion Nevadensis also occurs in the Upper Pogonip limestone on the north end of Pogonip Ridge, White Pine District, Nevada.
Two pygidiz occur at other localities, which may be referred to this genus. They belong to different species, but without the head parts a specific determination or name would be of little value.
FOSSILS OF THE LOWER SILURIAN. 95
Genus CERAURUS Green.
Ceraurus? sp. undt. Plate xii, fig. 17.
Glabella subglobose, marked by two pairs of short furrows that are only seen when looking from the sides; occipital segment strong; occipital furrow well defined, also the dorsal furrows; fixed cheeks unknown except a fragment near the dorsal furrow. Length of glabella, 3"; width, 3.25™™.
This curious little species is referred to the genus provisionally, as without other parts of the body its relations are not readily determined, and on the same account the specific identification is not attempted.
Formation and locality—Pogonip Group, lower eastern slope of ridge next east of the Hamburg Ridge, Eureka District, Nevada.
Genus SYMPHYSURUS Goldfuss.
Symphysurus? Goldfussi, n. sp. : Plate xii, fig. 16.
Glabella subclavate, convex, marked posteriorly by a pair of short, lightly impressed furrows; occipital ring strong and separated from the glabella by a well-defined but not deeply impressed furrow; dorsal furrows strong but shallow; fixed cheeks of medium width, rising from the dorsal furrows to the palpebral lobes, and sloping away to the front and back; frontal limb very short, hardly more than a line within the narrow border; postero-lateral limbs but little extended laterally, and marked by the exten- sion of the occipital furrow across their posterior side.
Surface apparently smooth.
This species is referred to Symphysurus on account of the subclavate glabella, and the direction of the facial sutures. In the absence of the thorax and pygidium a close generic reference is almost impossible with many of the species represented only by fragments.
Formation and locality—Pogonip Group, on the west slope of McCoy’s Ridge, Eureka District, Nevada.
96 PALEONTOLOGY OF THE EUREKA DISTRICT.
Genus BARRANDIA McCoy.
Barrandia ? McCoyi, n. sp. Plate xii, fig. 5. ;
General form of glabella and fixed cheeks, exclusive of the extension of the postero-lateral limbs, subquadrate. Glabella oblong, widening out a little towards the broadly rounded front; general surface moderately con- vex, and unbroken by any glabellar furrows; occipital ring of average width; occipital furrow distinct, but not deeply impressed; dorsal furrows quite strong in the specimen illustrated, and less so in other examples; fixed cheeks of average width, broadest and most elevated at the eyelobes from which they slope to the front and back; eyelobes situated back of a line uniting their anterior margins with the center of the glabella; the front of the head is bordered by a narrow, flattened rim; postero-lateral limbs triangular, terminating at a distance from the dorsal furrow equal to one-half the length of the glabella exclusive of the occipital ring.
Surface smooth to the unaided eye.
After an examination of the various species referred to this genus by Mr. Salter, we find that the Eureka form differs from most of them in the more anterior position of the eyelobes and the stronger dorsal furrows; features that, without known differences in the thorax and pygidium to sup- port them, we do not consider of generic importance. As the parts de- scribed, however, are all that is known of the species, the generic reference is somewhat provisional for this and also the following species.
Formation and locality—Pogonip Group, on lower eastern slope of ridge east of the Hamburg Ridge, Eureka District, Nevada.
Barrandia? sp.? Plate xii, fig. 6.
Glabella subclavate, the width of the base being about four-fifths of that of the anterior portion; front broadly rounded; general surface gently convex, curving down somewhat abruptly in front to the narrow, rim-like margin; occipital ring narrow and with a small tubercle at the center; occipital furrow shallow, but quite distinct; dorsal furrows clearly defined.
FOSSILS OF THE LOWER SILURIAN. 97
There are but slight traces of the fixed cheeks attached to the glabella. The species is characterized by the peculiarly shaped glabella.
Formation and locality—Pogonip Group, on the west slope of McCoy’s Ridge, Eureka District, Nevada.
Genus ILLA.NURUS Hall.
TIilzenurus Eurekensis, n. sp. Plate xii, figs. 4, 4a.
Head of medium width, semi-elliptical; glabella subquadrate, convex, a little longer than wide, as 5 to 4, with scarcely perceptible occipital or dorsal furrows; palpebral lobes nearly central on the margins; frontal mar- gin nearly straight; free cheeks a little longer than wide, with the base of the eyes cutting into them about the middle of the inner margin; genal angles broadly rounded.
The facial suture, cutting the frontal rim on a line with the outer edge of the eyelobe, passes directly to the anterior margin of the eyelobe; it encircles that and then curves gently outward to the posterior margin, form- ing a short, triangular-shaped lateral limb.
Surface minutely punctate.
The pygidie associated with the head parts vary very much. Two are illustrated on plate xii, figs. 12 and 19, neither of which has any re- semblance to the pygidium of Illenurus. Another, discovered since the plate was prepared, shows a short, smooth axial lobe, slight dorsal furrows, and gently convex, broad lateral lobes; this is probably the pygidium of this species, as numerous examples of the glabella occur on the same frag- ment of rock.
In the fourth volume of the Geology of Wisconsin a species of Ilex- nurus, J. convexus, is given as occurring in the Lower Magnesian limestone of that State, and the genus is also represented in the Potsdam sandstone, Illenurus quadratus Hall. In Nevada as yet it is only known from the horizon above that representing the Potsdam, or the correspondent of the Calciferous formation of the New York geologists.
Formation and localities—Lower portion of the Pogonip Group, on the east slope of the ridge east of the Hamburg Ridge; on second ridge south-
T7ODW
98 PALEONTOLOGY OF THE EUREKA DISTRICT.
east of the Jackson mine; a little to the northeast of Adams Hill, and on ridge southwest of Wood Cone, Eureka District, Nevada. In the White Pine District, Nevada, it was found in the central portion of the Pogonip limestone on Pogonip Ridge.
Genus ASAPHUS Brongniart. Asaphus Caribouensis, n. sp. Plate xii, figs. 7,74, b.
General form of the head semi-elliptical, moderately convex; glabella expanding quite rapidly in front of the eyelobes and obtusely angular in front; eyelobes situated back of a line uniting their anterior margins and the center of the glabella; postero-lateral limbs short and triangular in out- line. The associated free cheek is a little longer than wide and with a dis- tinctly marked border and genal spine.
The pygidiz occurring in the same hand specimens have a rather prominent medium lobe and smooth, depressed lateral lobes, without traces of segments on the latter.
Formation and localities —Pogonip Group, in the lower portion asso- ciated with the preceding species, and also in the upper beds at the west base of Caribou Hill, Eureka District, Nevada.
Asaphus? curiosa Billings. Plate xii, fig. 15. Asaphus ? curiosa Billings, 1865. Pal. Foss., vol. i, p. 318, fig. 305.
This curious pygidium, which is so closely allied to that described by Mr. Billings under the above name, shows traces of annulations on the me- dian lobe when the outer shell is removed. Three specimens were obtained, but no associated parts of the head or thorax.
Fragments of two other species of Asaphus occur in the upper layers of the Pogonip Group. One from Caribou Hill has a broad, smooth, planu- late pygidium with a very small and short median lobe, and is unlike any species known from American strata, being allied to some forms, described by Angelin, from Sweden. The other species is related to A. Caribouensis
FOSSILS OF THE DEVONIAN. PORIFERA.
Genus PALZOMANON Roemer.
Palzeomanon Roemeri, n. sp.
Plate xiii, fig. 12.
This is a crateiform or cup-shaped sponge of the general form of those referred to the genus Manon of the Jurassic and Cretaceous, and for the reception of the Paleozoic types of which Dr. Roemer founded the genus Palzeomanon, making P. cratera of the Niagara Group the type.
The example of P. Roemeri before me has a height of 65™", and a diam- eter of 50™™, contracting below to form a rounded base; the outer wall extends vertically to within a short distance of the summit, where it curves inward to the rounded marginal rim of the shallow cup; this has a depth of
-15™, Owing to the complete silicification and change of the original spicul, none of the surface characters have been preserved; the unmis- takable, striking form serves for the generic and specific identification.
Formation and locality—lLower horizon of the Devonian limestone at Lone Mountain, 18 miles northwest of Eureka, Nevada.
Genus ASTYLOSPONGIA Roemer. Astylospongia, sp. ?
Several specimens of arather small, globose or flattened oviform sponge were obtained from the center of cherty concretions. The largest has a diameter of 30™™, and presents in a transverse section numerous fine, radi- ating tubes or canals studded with fine spicule. Owing to the imperfect preservation of all the specimens, it is impossible to determine their specific relations to forms already described.
Formation and locality—Lower horizon of the Devonian limestone at
Lone Mountain, 18 miles northwest of Eureka, Nevada. 99
100 PALEONTOLOGY OF THE EUREKA DISTRICT.
Genus STROMATOPORA Goldfuss.
One or two species of this genus occurs very abundantly at several horizons throughout the Devonian formation. They are not in a condition to admit of specific determination without first having a series of thin sec- tions prepared and a special study made in connection with other species, the material for which is not available at present.
ACTINOZOA.
Owing to the meagerness of the material representing some of the spe- cies, and the fact that much larger collections may be obtained for future study, itis not considered best to attempt to illustrate and describe this group until it can be done in a more satisfactory manner than at present. A short note of each of the identified species and a notice of such as are con- sidered new and undescribed is given. The specific identifications were chiefly made by a direct comparison of the Nevada specimens with authen- ticated specimens in the beautiful and extensive collection of the New York State Museum and the private collection of Prof. James Hall.
Favosites hemispherica Yandell and Shumard. See Geol. Surv. Michigan, vol. iii, pt. 2, p. 25, 1876.
Several specimens of the cylindrical form of growth occur in the collec- tions, but none of the large hemispheric or turbinate forms so characteristic of the species in the Corniferous limestone of New York, Ohio, Canada, ete.
Formation and localities —Lower horizon of the Devonian limestone at Lone Mountain, 18 miles northwest of Eureka, and also at the head of the Reese and Berry Cafion, Eureka District, Nevada.
Favosites basaltica Goldfuss. 1829. Petref. Germ., vol. i, p. 78.
A comparison with the figures given by Goldfuss, and also with a speci- men from Silesia, shows a very close specific resemblance between them and the Nevada specimens, and one of the latter appears to be specifically identical in all its characters with this species. Other specimens vary in the size of the cells from 2™, the usual size of those in F. basaltica, to 3™™; smaller cells not over 1™™ in diameter occur on the same specimen. In the presence, however, of a single row of pores on each side of the cells, numer-
FOSSILS OF THE DEVONIAN. 101
ous transverse diaphragms, the general size of the cells, and the mode of growth, the species is similar to the European form of I’. basaltica. Formation and localities —Lower horizon of the Devonian limestone at Lone Mountain, 18 miles northwest of Eureka; at the head. of the Reese and Berry Cation, and on the ridge of Atrypa Peak, Eureka District, Nevada.
Favosites, n. sp.
Corallum growing in hemispherical or irregularly formed masses made up of small tubes varying in size from 1™™ to 1.5", which are without any distinct arrangement in relation to size, the smaller cells occurring together or with the larger interspersed among them. On the upper surface of the corallum the cell walls are thickened and have a beaded appearance which is not observed in a transverse section of the tubes a short distance below where the walls are strong and the tubes distinctly polygonal and not rounded as at the apertures, Transverse diaphragms entire, closely ar- ranged or separated up to a distance equal to an entire diameter of the tube Mural pores not well determined, but there is apparently a single row of rather large size on each side.
The largest fragment obtained has a depth of 8™, and the diameter of the entire corallum was from 15™ to 20.
In the character of the cell-walls at the surface of the corallum, the diaphragms in the tubes, and form of growth, this species is not unlike Favosites? Argus Hall, of the Hamilton Group of New York, but in the small size of the cells, and the absence of the very large cells among the smaller ones in the latter species, it is very distinct from it.
Formation and locality—Lower horizon of the Devonian limestone at Lone Mountain, 18 miles northwest of Eureka, Nevada.
Fistulipora, sp.?
Silicified specimens of a well-characterized species of this genus occur in association with fossils of the Upper Helderberg horizon. Its specific relations are not yet determined.
Formation and locality—Devonian limestone, lower horizon, Atrypa Peak Ridge, Eureka District, Nevada.
102 PALEONTOLOGY OF THE EUREKA DISTRIOT.
Alveolites Rockfordensis Hall? 1864. Twenty-third Ann. Rep. N. Y. State Cab. Nat. Hist., p. 229.
The cell apertures open more directly with the plane of the surface in. the Nevada specimens than in those from the Chemung Group of Iowa, but otherwise there is a marked specifie similarity and a provisional reference is made to A. Rockfordensis, of the species from Nevada.
Formation and locality—Upper horizon of the Devonian limestone, on ridge east of Yahoo Canon, Eureka District, Nevada.
Cladopora pulchra Rominger? 1876. Geol. Surv. Michigan, vol. iii, pt. 2, p. 55.
The Eureka specimens although occurring in the upper beds of the Devonian are closely related to the Upper Helderberg species, C. pulchra, and appear to be specifically identical with it. The obtaining of more and better-preserved examples may prove the two forms to be specifically dis- tinct, but with our present knowledge a separation does not appear to be necessary.
Formation and locality—Upper horizon of the Devonian limestone, on ridge east of Yahoo Cafion, Eureka District, Nevada.
Cladopora, sp. (und’t).
This is a larger branching form of which worn sections alone have been obtained. It occurs in the central or lower portion of the Devonian formation west of Spring Valley.
Numerous fragments of an imperfectly-preserved species of Cladopora occur in the silicious Devonian limestone; the stems are usually about 5™™ in diameter and associated with a species of Stromatopora in such quanti- ties as to characterize many beds where other fossils are wanting.
Thecia ramosa Rominger? 1876. Geol. Surv. Michigan, vol. iii, pt. 2, p. 69.
This rare and interesting form occurs in the lower portion of the De- vonian, corresponding to its position in the Upper Helderberg limestones at the Falls of the Ohio, and in the State of Michigan. Dr. Rominger describes it as formed of “‘stout, branching, sometimes reticulated, anasto- mosing stems, from half an inch to two inches in diameter, composed of thick-walled, conico-cylindrical tubes ascending and diverging from a cen- tral imaginary axis. Orifices unequal, of polygonal form, from one to two millimeters wide at the edges of the dilated margins, radiated by twelve
FOSSILS OF THE DEVONIAN. 103
prominent spinulose crests, extending through the whole length of the channels. Transverse diaphragms partly simple and complete, partly in- completé, represented by lateral squamiform, horizontal leaflets. Pores large and very numerous.”
The species is represented by a single portion of a stem 28" in diam- eter; the polygonal, unequal orifices are about 1"™ in diameter and present the character given them by tbe author of the species, as do the diaphragms and large pores. Although there is no evidence of its being a branching form, as there is but a portion of a stem in the collections, it seems extremely probable from the close specific characters of the portion we have that it is specifically identical with the Upper Helderberg species.
Formation and locality—lLower horizon of the Devonian limestone, central portion of Gray’s Canon, Eureka District, Nevada.
Syringopora Hisingeri Billings. 1859. Can. Jour., un. ser., vol. iv, p. 116.
In New York, Canada, Indiana, etc., this species occurs in the Upper Helderberg limestones, but at The Gate, northwest of Eureka, it is associ- ated with fossils of the Chemung horizon in the Upper Devonian beds. Numerous fine specimens were found, so that the specific identification hardly admits of question.
Syringopora perelegans Billings. 1859. Can. Jour., n. ser., vol. iv, p. 117.
Specimens referable to this species were found in the Lower Devonian beds at Lone Mountain, and also at the summit of the formation at The Gate, northwest of Eureka, showing its range through the entire Devonian forma- tion. It is extensively distributed in the strata of the hills east and west of Yahoo Cation. At the east it occurs in the Upper Helderberg limestones.
Aulopora serpens Goldfuss? See Geol. Surv. Michigan, vol. iii, pt. 2. 1876.
In size, manner of branching and reuniting of the tubes, this species of Aulopora from the Lower Devonian beds of Gray’s Cation corresponds to the descriptions and illustrations given of the American form identified with that species, and a comparison with the figures given by Goldfuss indicates that this identification is correct, although his figures show a some- what smaller and less robust form.
104 PALEONTOLOGY OF THE KRUREKA DISTRICT.
Cyathophyllum corniculum Milne-Edwards? See Geol. Sury. Michigan, vol. iii, pt. 2, p. 102.
A direct comparison with examples of this species from the Upper Helderberg limestones at the Falls of the Ohio shows very little difference between them and a similar form from the upper beds at The Gate, north- west of Eureka, where it is associated with Syringopora Hisingeri, another Upper Helderberg species. Until more perfect specimens are obtained a provisional reference is made as above.
Cyathophyllum rugosum Edwards and Haime. See Geol. Surv. Michigan, vol. iii, pt. 2, p. 106. 1876.
Well-marked silicified specimens of this species occur in association with Cyathophyllum Davidsoni and Diphyphyllum Simcoense, in the Lower Devonian of Lone Mountain. They are usually more or less subhemis- pherical masses with occasional cells of much larger size than distinguished the Upper Helderberg examples from the Falls of the Ohio; otherwise no essential differences were observed.
Cyathophyllum Davidsoni Milne-Edwards. See Geol. Surv. Michigan, vol. iii, pt. 2, p. 107. 1876.
Occurs with the preceding species, and is readily identified with the forms from the Hamilton Group of Iowa. It appears to be little more than a small-celled form of the associated C. rugosum.
Cyathophyllum, n. sp.
A compound corallum formed of corallites that increase by calicular and interstitial gemmation. The corallites are usually circular, and vary from 3™" to 25™" in diameter in the same specimen. Frequently several will spring from the calyx of an old corallite, increase rapidly in size, forming a subturbinate form, with a calyx broad and expanded about the margin, and having a rather deep central depression, the bottom of which is sometimes evenly rounded, and again with a small central protuberance formed by the union of the radiating lamelle. The interstitial corallites start from the sides of the older ones and arise alongside, usually remaining at the same rela- tive height with the general surface of the corallum; the young or smaller corallites wanting the broad margin to the calyx, the deep depression occu- pying the entire area.
The lamelle are crenulated on the margin and number from 50 to 60 in the circumference of the calyx.
FOSSILS OF THE DEVONIAN. 105
The interlamellar spaces are divided by numerous transverse plates; the central transverse diaphragms are very small if present at all.
This is a very distinct and handsome species allied to C. rugosum, or what that species would be if growing in the same manner. Still, it does not appear that the two are specifically identical. It grows in quite large masses, as a fragment shows a depth of 15™.
Associated with the preceding species at Lone Mountain, 18 miles northwest of Eureka, Nevada.
Cyathophyllum, n. sp.
Single conical polyparia, annulated by coarse undulations of growth, and longitudinally striated by the septal furrows. The bases of root-like prolongations from the outer surface often obscure these features. Calyx very deep and opening out rapidly. A specimen 35™" in height has a calyx 22™ in depth, with a diameter of 26™" at the margin. Lamelle from 50 to 60 in number. This is a strongly marked form, unlike any other known to me.
Associated with the preceding species.
Acervularia pentagona Goldfuss. See Geol. Expl. Fortieth Par., vol.iv,p.31. 1877.
In the Paleontologic report of the Geological Exploration of the For- tieth Parallel, Mr. F. B. Meek has identified this species from the Devonian limestones of the White Pine Mountains, and given an illustration of the Nevada specimens. The species, as it occurs in the Middle Devonian, at the head of Brown’s Cation, is essentially the same as at White Pine, and there appears to be no question of its identity with the European species.
Pachyphyllum Woodmani (White) H. & W. 1864. Twenty-third Ann. Rep. N. Y. State Cab. Nat. Hist., p. 231.
This is a strongly marked species, and a comparison of specimens from the typical locality at Rockford, Iowa, with those from Nevada, shows no appreciable differences between the Chemung form and the Upper Devonian specimens occurring on the ridge west of Yahoo Camion, in the Eureka District.
Diphyphyllum Simcoense Billings. See Geol. Surv. Michigan, vol. ili, pt. 2, p. 123. 1876.
This very abundant species of the great Corniferous coral reef of Can- ada, New York, Indiana, etc., is represented by a number of specimens from Lone Mountain, but not found elsewhere. The stems forming the colonies
106 PALEONTOLOGY OF THE EUREKA DISTRICT.
or corallum are larger than the average in the species, but the specific iden- tity of the eastern and western species is a very close one.
Cystiphyllum Americanum Milne-Edwards. See Geol. Surv. Michigan, vol. iii, pt. 2, p. 138. 1876.
As there is considerable variation in the size and form of the polyparia and the vesicles, as well as the distinctness of the plications, in the forms referred to this species, it is quite probable that the one under consideration will fall within its limits. It presents all the characters common to many New York and Ohio specimens, and we have little hesitancy in referring it to this species.
Formation and localities —Lower horizon of the Devonian limestone; on the divide at the head of the Reese and Berry Cain, and at Lone Mountain, 18 miles northwest of Eureka, Nevada.
Cystiphyllum, n. sp.
There are two species of Cystiphyllum in the collection that do not appear to be specifically allied to any described forms. One has the outer surface studded with little nodes and the calyx of considerable depth, with numerous sharp lamellz that in some instances are nearly concealed by coarse vesicles. ‘The corallum is about 40™™ in length, 20 to 25™™ in diam- eter at the summit, and more or less strongly marked by broad ridges of growth. The other species has the latter character in a modified degree, but lacks the nodulose surface; the interior of the calyx is filled with vesicles from the center of which a young corallum springs.
At Lone Mountain with the preceding and other species.
Besides the above-mentioned forms, there are two species of Zaphrentis too imperfect for description, and a large Cyathophylloid coral of unknown specific relations.
BRACHIOPODA. Genus LINGULA Bruguiére.
Lingula Lena Hall. Plate xiii, fig. 2. Lingula leana Hall, 1867. Pal. N. Y., vol. iv, p. 9, pl. ii, fig. 12. The Nevada shell is not quite as elongate or rounded in front as much as the New York examples of this species, but it agrees with them in all
FOSSILS OF THE DEVONIAN. 107
essential particulars. It is a rare species, both in the Hamilton Group of New York and the lower horizon of the Devonian formation at Lone Mount- ain, 18 miles northwest of Eureka, Nevada.
Dimensions: length, 17™"; greatest breadth, 12™.
Lingula Ligea Hall. Plate ii, fig. 2. Lingula ligea Hall, 1860. Thirteenth Ann. Rep. N. Y. State Cab. Nat. Hist., p. 76. Ibid., 1867. Pal. N. Y., vol. iv, p. 7, pl. i, fig. 2a, b; pl. ii, fig. 8.
This pretty and symmetrical little shell is represented by one specimen that in external appearance is identical with specimens of L. Ligea now before me, from the Hamilton Group of New York.
In a layer of limestone, about 59 feet above that containing the above- mentioned shell, a number of examples of a form that may be only a varia- tion of L. Ligea were collected. In as close a genus as Lingula, however, this variation is unusual, and a varietal distinction is made.
Lingula Ligea var. Nevadensis, n. var.
Plate ii, fig. 3.
Shell below the average size of L. Ligea, and with more rounded sides and pointed beaks than that species.
Surface marked by fine concentric strize of growth.
The interior of the ventral valve shows the path of advance of two central muscular scars, and also a lateral scar on each side. The impres- sions of the scar are too faint to be of any service in determining their character or number.
Formation and locality of this and the preceding species, Upper Devo- nian of Rescue Hill, Kureka District, Nevada.
A species undistinguishable from this occurs in the Lower Devonian of the south slope of Sentinel Mountain, Eureka District, Nevada.
108 PALEONTOLOGY OF THE EUREKA DISTRICT.
Lingula Alba-pinensis, n. sp.
Plate ii, figs. 1, La.
Shell small, elongate, elliptical, moderately convex; beaks obtusely angular; sides of shell curving with a gentle convexity from the lateral cardinal slope to the rather abruptly rounded front.
Surface marked by fine concentric strize and rather strong lines of growth for so small a species. No radiating lines have been observed.
Dimensions: length of the largest specimen found, 6"; width at cen- ter, 3™™. The other specimens average 2.5" in length by about 1.5™™ in width. ae
Associated with these there is a minute form that differs in being more broadly elliptical; otherwise it may be referred to L. Alba-pinensis. The latter species belongs to the Devonian Group of Lingula, of which LZ. Melie and L. Ligea are types, and is also very much like the young of L. myti- loides of the Carboniferous.
In the Eureka District Lingula Melie (see pl. ii, fig. 4) is the only Lin- gula yet discovered in the White Pine shale.
Formation and locality—Upper Devonian, White Pine shale, White Pine District, Nevada.
Lingula Lonensis, n. sp. Plate xiii, figs. 1, la.
Shell broadly ovate; beaks obtusely angular, the sides sloping away at an angle of about 110°, and then extending forward with more or less con- vexity to the broadly rounded front.
Surface marked by numerous lines of growth that give a finely imbri- cated appearance to the outer portions of the shell.. No radiating lines or strize are visible on the specimens before us. Two specimens measure: length, 10™,; width, 8"; length, 11"; width, 10™™, respectively.
The specimens are imbedded in a shaly limestone, and are very much compressed, which gives them a broader outline than when in a natural condition.
The species is allied to Lingula Lucretia Billings (Pal. Foss., vol. ii, pt.
FOSSILS OF THE DEVONIAN. 109
1, p. 13, fig. 3. 1874), from the Gaspé limestone, but differs in surface char- acters.
Formation and locality —In the lower horizon of the Devonian limestone of Lone Mountain, 18 miles northwest of Eureka, Nevada.
Lingula Whitei, n. sp. Plate xiii, fig. 3.
Shell above the average size, subelliptical in outline, the length and breadth as 5 to 3; the cardinal slopes of the dorsal valve converge at an angle of 20°; front broadly rounded and sides subparallel, curving slightly outward. ‘The dorsal valve is quite convex and a little flattened along the center towards the front.
Surface marked by fine concentric and radiating strie, and when the outer shell is partially decorticated strong radiating lines, crossed by raised concentric strix, give a somewhat reticulated appearance to the sur- face. The length of the specimen described is 29"™ and the breadth 17™.
The general outline of the species is similar to that of Lingula squamt- formis Phillips (Mon. Brit. Foss. Brach. Davidson, vol. ii, p. 205, pl. xlix, figs. 1-10), of the Carboniferous rocks, but the valves are more convex and the scars on the interior of the dorsal valve differently arranged. I know of no closely related Devonian species.
A cast of the interior of the dorsal valve was obtained from a fragment of limestone in which the shell adhered to the matrix by its exterior sur- face and left the imprint of the vascular markings and muscular scars beautifully and distinctly defined on the cast. It is of great interest, as it affords the opportunity for the comparison of the structure with that of living forms of the genus, and shows that the strong generic resemblance of the outer surface of the shell to that of recent species is also present in the more important muscular scars on the interior surface.
At the posterior end, just within the apex of the valve, the cast of the elongate divaricator muscular scar (d, plate xiii, fig. 3) is well impressed; it is transverse and arches forward a little at the sides, back of the initial points of the path of the advance of the posterior adductor and adjustor
110 PALEONTOLOGY OF THE EUREKA DISTRICT.
muscular scars. The posterior adductor scars (pa) are large, elongate-oval in outline, and so situated that their anterior portions cross a line drawn through the transverse center of the valve, while the posterior ends point back to their path of advance; they are separated by the track of advance of the anterior adductor scars (aa), which are seen just in advance of them as very small, slightly impressed oval spaces. The area of the ad- justor muscular scars (ad) and their path of advance is, as a whole, more or less triangular, and situated one on each postero-lateral portion of the valve. The front margin of the area is rather broad and divided into four small, somewhat indistinct lobes; posteriorly the area contracts to the in- itial point of the path of advance; two scars appear to be defined on the anterior two-thirds of each area; they are elongate and include two of the little lobes of the anterior margin within the area of each, and appear to represent the point of attachment of the exterior and posterior adjustor muscles; there is a small space divided off by raised lines that may be the central adjustor scar, but it is not clearly defined.
Between the areas of the adjustor scars and the large central area of the adductors there is a sharp, narrow ridge that distinctly separates them. A narrow elongate area (pp), outside of the area of the adjustor scars, was probably the point of attachment of the posterior parietal muscle, and the lateral and outer walls of the perivisceral cavity seem to have left evidence of their presence on the margins (w) of the central area.
The great pallial sinuses approximate quite closely towards the front, curving gently outward and backward around the central area to opposite the anterior margin of the area of the adjustor muscular scars, around which they curve to the narrow margin just within the exterior border of the shell; their further course cannot be traced, but, from the narrow area between the posterior parietal area and the margin, the sinuses must have been very narrow, and with very minute, if any, lateral or internal ramus- cules. The anterior lateral ramifications of the sinuses are strongly defined as they spring from the main sinus, becoming smaller and bifurcating or branching towards the margin of the valve; no inner ramifications are to be seen on the space (7) between the great sinus and the perivisceral area on the dorsal valve, a feature, however, that is well shown on a fragment
FOSSILS OF THE DEVONIAN. ib
of a ventral valve, where this area and the space occupied by the anterior adductor scars in the dorsal valve is occupied by the short, strong ramuscules from the great sinuses. Over the central portion of the cast the radiating lines of the inner surface of the shell are seen crossing the muscular scars and vascular markings, and somewhat complicate the study of the latter. The draughtsman has represented these, as also all the details, with accuracy.
On comparing this with the interior of the corresponding valve of Lingula Elder, of the Trenton limestone of Wisconsin, described by Prof. R. P. Whitfield,* we observe in the latter the strong extension of the great pallial sinuses nearly around the posterior end of the perivisceral cavity and back of the divaricator scar; the greater anterior expansion of the pal- lial sinuses, and the smaller area of the adjustor muscular scars. The former character is unknown in L. Whitei, but is present in the recent spe- cies so beautifully illustrated by Hancock.®
The two paleozoic species possess, however, the large posterior ad- ductor scars, the postero-lateral adjustor scars, and the absence of the inner ramuscules of the posterior extension of the pallial sinuses, features that distinguish them from Lingula anatina and other living species.
The character of the anterior ramifications of the great sinuses of _L. Whitei resembles that of ZL. affinis more closely than that of any other species.
To afford the means of a direct comparison between the Silurian, De- vonian, and a recent Lingula, an outline figure of the interior of the dorsal valve of a species from each horizon is given on plate xxi, figs. 18, 19, and 20, in which the muscular scars and vascular markings of each are shown.
The specific name of the Devonian species is given in honor of Dr. Q. A. White, geologist and paleontologist.
Formation and locality—Lower portion of the Devonian limestone, southwest spur of Atrypa Peak, Eureka District, Nevada.
® Amer. Jour. Sci., 3d ser., vol. xix, p. 472, 1880. * Organization of the Brachipoda, by Albany Hancock, esq., 1858. Trans. Royal Phil. Soo., pls. 64-66.
112 PALEONTOLOGY OF THE EUREKA DISTRICT.
Genus DISCINA Lamarck.
Discina minuta Hall. Plate xiii, fig 5. Orbicula minuta Hall, 1843. Geol. Rep. Fourth District of New York, p. 180. Discina minuta Hall, 1867. Pal. N. Y., vol. iv, p. 16, pl. i, fig. 16 ab.
This small and pretty species is represented by a number of examples that correspond closely with the typical specimens from the Marcellus shale of New York, and which are considered identical with them, although separated by a distance of 1,800 miles, and occurring at a different horizon in the Devonian Group.
The New York specimens vary from 1.5™™ to 4™™ in diameter, while the largest from Nevada is 4™™ in its greater diameter, and of about the same convexity as examples of the same size from New York.
Formation and locality—Upper horizon of the Devonian limestone, at The Gate, northeast of Eureka, Nevada.
Discina, sp. (?)
Considerable interest is attached to this shell, as it is very rare and the only species of the genus from the Lower Devonian of the Rocky Mountain area, but one imperfect specimen showing the two valves united occurs in the collections. In general form it is not unlike Discina media of the Hamilton Group of New York.
Formation and locality—Lower Devonian of Lone Mountain, 18 miles northwest of Eureka, Nevada.
Discina Lodensis Hall. Plate ii, figs. 5, 5a.
Orbicula lodensis Hall, 1843. Geol. Rep. Fourth Dist. N. Y., p. 223. lodensis Vanuxem, 1842. Geol. Rep. Third Dist. N: Y., p. 168. (Wood cut used in advance of publication of the Report on the Fourth District.) Discina lodensis Hall, 1867. Pal. N. Y., vol. iv, p. 22, pl. i, figs 14 a-f; pl. ii, fig. 35. lodensis Rathbun, 1874. Bull. Buffalo Soc. Nat. Sci., vol. ii, p. 257. Ibid., 1878 Proc. Boston Soc. Nat. Hist., vol. xx, p. 17. Compare D. media Hall, 1857. Pal. N. Y., vol. iv, p. 20, pl. ii, figs. 25-28.
FOSSILS OF THE DEVONIAN. 113
On a direct comparison with authentic specimens of this species from the Genesee slate of New York, no differences appear that are of specific value.
Professor Hall says, in comparing D. media of the Hamilton Group of New York with D. Lodensis, that the former may possibly be only a well- marked variety of D. Lodensis (cbid., p. 21). In this I would fully concur. In studying a good series of Discina nitida, as illustrated by Davidson, con- siderable range of variation in convexity, outline, and the position of the apex is apparent, and no doubt other species are subject to as great varia- tions, arising, as {hey may, from the nature of the local environment during the life of the animal; the character of the sediments and conditions of fossilization.
Mr. Rathbun identifies this species from the Devonian of Brazil, 8. A.
Formation and locality—Upper Devonian. White Pine shale on the east side of Applegate Canon, White Pine Mining District, Nevada.
PHOLIDOPS Hall.
Pholidops bellula, n. sp. Plate ii, figs. 6, 6a, b.
Shell minute, broadly oval, depressed; apex eccentric, situated about one-third the distance between the anterior and posterior margins.
Surface marked by a few fine concentric striz.
The interior of the dorsal valve presents a rather wide, unbroken mar- gin surrounding the rounded concave interior. Near the center of the shell two oval, slightly-oblique elevated scars occur. No other scars are discern- ible. In the cast the bilobed scars are shown as a rather deep impression, the apex of the shell being entirely truncated. Substance of the shell cal- careous. Average size, 2.5" by 2™. No ventral valves were discovered.
In general form this species resembles Pholidops ovalis Hall, (‘T'wenty- eighth Ann. Rep. N. Y. State Mus. Nat. Hist., p, 149, pl. xxi, figs. 1, 2) of the Niagara Group, and P. Hamiltonie Hall (Pal. N. Y., vol. iv, p. 32, pl. iii, figs. 6-9, 1867) of the Hamilton Group of New York. It differs from each,
and is specifically distinct from any form with which we are acquainted. 80DW
114 PALEONTOLOGY OF THE EUREKA DISTRICT.
Formation and locality—lLower Devonian of Brush Peak, Eureka Dis- trict, and at the same horizon at Lone Mountain, 18 miles northwest of Eureka, Nevada.
Pholidops quadrangularis, n. sp. Plate ii, fig. 7.
Shell broadly oval, or subquadrangular; moderately elevated. Sides nearly straight, which gives the quadrangular outline to the shell. Apex eccentric and a little elongate. Slope from the apex to the margin uniform. Surface marked by irregular, not very prominent lamellose striz. Substance of shell calcareous. Dimensions: Breadth, 5.5™"; length, about 6.5™™.
This species is unlike any described form known to us, and although only represented by a single valve showing the exterior, it is too well marked to be confused with any species from the Eastern United States.
Formation and locality—Lower Devonian at Lone Mountain, 18 miles northwest of Eureka, Nevada.
Genus ORTHIS Dalman.
Orthis McFarlanei Meek. Orthis Mc. Farlanei Meek, 1868. Trans. Chicago Acad. Sci., vol. i, p.88, pl. xii, figs. 1a—-h.
This large species is so strongly marked by its peculiar form that the identification is rendered very satisfactory, although based on imperfect specimens. Its short hinge line, great convexity of the dorsal valve, and narrow umbonal region give it the appearance of Pentamerus galeatus, as mentioned by Meek. The Nevada specimens show the fine radiating strize and minutely punctate surface with great distinctness, as in the original types of the species from the Mackenzie River Basin, British America. Mr. Meek states that he had seen specimens which he believed to be identical with this species from the Devonian of Iowa and Illinois.
Formation and locality—Lower horizon of the Devonian limestone, west slope of County Peak, Eureka District, Nevada.
FOSSILS OF THE DEVONIAN. 115
Orthis impressa Hall. Plate xiii, fig. 13. Orthis impressa Hall, 1843. Geol. Rep. Fourth District of New York, p. 268 and p. 267, impressa eset Pal. N. Y., vol. iv, p. 60, pl. viii, figs. 11-19. impressa Whitfield, 1883. Geol. of Wisconsin, vol. iv, p. 326, pl. xxv, figs. 13-15. Compare 0. Tulliensis Vanuxem, 1842, Geol. Rep. Third District, New York, p. 55. O. Towensis Hall. 1858, Geol. Surv. Iowa, vol. i, pt. 2, p. 488, pl. ii, figs. 4 a-i,and O. Me. Farlanei, Meek, loc. cit., p. 114.
In New York this species is found in the Chemung Group, and is re- garded by Professor Hall as closely allied to Orthis Tulliensis, of the Tully limestone, which occurs about 1,000 feet lower in the strata, no species of Orthis being known in the interval. In Nevada the relative position of the two forms is somewhat reversed; QO. impressa is found only at the base of the Devonian, and 0. Tuiliensis at the base and near the summit, 4,000 feet above.
A comparison of the Chemung specimens from New York with the Nevada examples shows a most perfect identity between them, while the O. Tulliensis is quite as decided in its characters as in New York. Associated with O. impressa, at Lone Mountain, there is a more convex form that is of the type of 0. Tulliensis, and it may be referred to it.
Formation and localities—Lower horizon of the Devonian limestone, Comb’s Peak; 2 miles east of Castle Mountain; west slope of County Peak, and Lone Mountain, 18 miles northwest of Eureka, Eureka District, Nevada.
Orthis Tulliensis Vanuxem. Plate ii, figs. 12, 12a, Orthis tulliensis Vanuxem, 1842. Geol. Rep. Third District New York, p. 164 and fig. 2, on p. 163. tulliensis Hall, 1867. Pal. N. Y., vol. iv, p. 55, pl. vii, figs. 5a-k.
Compare O. Towensis Hall, 1858. Geol. Rep. Iowa, vol. i, pt. 2, p. 488, pl. ii, figs. 4a-7.
The facts connected with the distribution and range of this species have been mentioned in the notes of the preceding species. ‘The specimens from The Gate, northwest of Eureka, are not quite as gibbose as the majority
116 PALEONTOLOGY OF THE EUREKA DISTRICT.
of the New York examples, but their specific identity is unquestionable. The specimens from the lower horizon at Lone Mountain are preserved in a different matrix and the outer surface is mostly exfoliated, which gives them a dissimilar appearance, but no specific variation can be determined between them and those from the upper horizon at The Gate.
Formation and localities —Devonian limestone, higher beds at The Gate, northwest of Eureka, and lower beds at Lone Mountain, 18 miles northwest of Eureka, Nevada. ;
Genus SKENIDIUM Hall.
Skenidium Devonicum, n. sp.
Plate xiii, figs. 4, 4a.
Shell small, subpyramidal; hinge line a trifle shorter than the greatest width of the shell; a sharp, median fold marks the ventral valve and a slight sinus the dorsal. Ventral valve elevated, beak slightly incurved over a high area that is divided midway by a large deltoidal foramen. Dorsal valve nearly flat; area very short; foramen short and broad; cardinal pro- cess extends as a median septum towards the lower portion of the valve.
Surface marked by strong radiating striz that increase by implanta- tion.
Dimensions: length, 3.5""; breadth, 4.5""; elevation of ventral valve, LD
This species has a Jess elevated area, finer and sharper strize than Ske- nidium insignis =(Orthis insignis Hall, Pal. N. Y., vol. iii, p. 173, pl. xiii, figs. 13-15, 1859) of the Lower Helderberg limestone of New York; otherwise the two strongly resemble each other.
This is the first time that the genus Skenidium has been reported as occurring in Devonian strata, the species previously referred to it coming from the Lower and Upper Silurian formations.
Formation and locality.—Devonian limestone, lower horizon, Lone Mountain, 18 miles northwest of Eureka, Nevada.
FOSSILS OF THE DEVONIAN. 11%
Genus STREPTORHYNCHUS King. Streptorhynchus Chemungensis Conrad (Sp.). Plate xiii, figs. 7, 16. Strophomena Chemungensis Conrad, 1842. Jour. Acad. Nat. Sci. Philad., vol. viii, p. 257. bifurcata Hall, 1842. Geol. Rep. Fourth District New York, p. 266, fig. 2. arctostriata Hall, 1842. Ibid., p. 266, fig. 3. pectinacea Hall, 1842. Ibid., p. 266, fig. 4. Orthis perversa Hall, 1857. Tenth Ann. Rep. N. Y. State Cab. Nat. Hist., p. 137. inequalis and O. pravus Hall, 1858. Geol. Lowa, vol. i, pt. 2, p. 490. Streptorhynchus Pandora Billings, 1860. Canadian Jour., vol. v, p. 266, and Geology of Canada, 1863, p. 369, fig. 384. Orthisina arctostriata Hall, 1860. Thirteenth Ann. Rep. N. Y.State Cab. Nat. Hist., p. 80. alternata Hall, 1860. Jbid., p. 81. Streptorhynchus Chemungensis Hall, 1867. Pal. N. Y., vol. iv, p. 67, plates iv, ix, x. var. A. Streptorhynchus pandora Billings. var. B. S. arctostriata Hall. var. C. S. perversa Hall. var. D. 8. pectinacea Hall, 1867. Pal. N. Y., vol. iv, pp. 68-73. Pandora Nicholson, 1874. Pal. Prov. Ontario, p. 70. Hemipronites Chemungensis, var. arctostriata Meek, 1877. Geol. Expl. Fortieth Par., vol. iv, p. 35, pl. iii, fig. 2.
Three quite distinctly marked varieties of this extremely variable spe- cies were collected from the Devonian limestone of Lone Mountain and the Kureka District.
The first is that of the typical form of shell described by Conrad, many illustrations of which are given by Professor Hall in volume four of the Paleontology of New York (plate x, figs. 11-17). The Nevada form is shown on our plate xiii, fig. 16. Another, and by far the most abundantly represented variety, is var. Pandora (Pal. N. Y., vol. iv, pl. iv, figs. 11-19; pl. ix, figs. 18-25, 27; and pl. x, fig. 1).
In New York the species ranges from the Upper Helderberg up into the Chemung Group, and in the Eureka District from the base to the summit of the Devonian limestone. At The Gate, northwest of Eureka, the small form characteristic of the Chemung Group of New York, also of the Cor- niferous limestone of the Upper Helderberg, occurs in a dark limestohe. This is the exact locality from which the specimen mentioned by Mr. Meek was obtained and referred by him to the variety arctostriata. The speci-
118 PALEONTOLOGY OF THE EUREKA DISTRICT.
men as figured by Mr. Meek is like those before me, one of which (plate xiii, fig. 7) varies slightly from his figure and those illustrated by Professor Hall (Pal. N. Y., vol. iv, pl. x, figs. 1, 2.)
The other variety represented in Nevada, var. perversa, is limited to the Lower Devonian horizon, although found at somewhat widely separated localities. In New York, it is found both in the Upper Helderberg and Hamilton Groups.
Formation and localities —Devonian limestone, Lone Mountain, 18 miles northwest of Eureka, and several localities within the Eureka District, Nevada; also on north end of the Pinon Range, Nevada.
Genus STROPHOMENA Blainville. p Strophomena rhomboidalis Wilckens (Sp.). For synonyms, see Davidson’s Monograph of the British Silurian Brachiopoda, vol. iii, p. 281; and Pal. N. Y., vol. iv, p. 76.
This widely-distributed species was found in but one locality on Lone Mountain, not being recognized within the limits of the map of the Eureka District. The specimens are of the ordinary character, with rather strong concentric undulations. They are associated with Strophodonta perplana, S. ampla, and Streptorhynchus Chemungensis, var. Pandora.
The species has been recognized in the Lower Carboniferous of Utah, and at the same horizon in the Spring Mountain Range of Nevada, but not before in the Devonian of the Rocky Mountain.
Formation and localities—Lower Devonian horizon of Lone Mountain, 18 miles northwest of Eureka, Nevada; also in the Lower Devonian, on the north end of the Pinon Range, Nevada.
Genus STROPHODONTA Hall. Strophodonta demissa Conrad (Sp.). Plate ii, figs. 9, 9a, b.
Strophomena demissa Conrad, 1842. Jour. Acad. Nat. Sci. Philad., vol. viii, p. 258, pl. xiv, fig. 14.
Strophodonta dimosa(?) Owen, 1852. Geol. Surv. Wis., Iowa, and Minn., tab. iii, A, fig. 14.
FOSSILS OF THE DEVONIAN. 119
Strophomena (Strophodonta) demissa Hall, 1857. Tenth Ann. Rep. N. Y. State Cab. Nat. Hist., p. 137. Strophodonta demissa Hall, 1858. Geol. Iowa, vol. i, pt. 2, p. 495, pl. iii, fig. 5. Strophomena demissa Billings, 1861. Canadian Jour., vol. vi, p. 341, figs. 116-118, demissa Billings, 1863. Geology of Canada, p. 367, figs. 377a-d. Strophodonta demissa Hall, 1867. Pal. N. Y., vol. iv, pp. 81, 101, and 114, pls. xi, xii, Xvii, xix. Strophomena (Strophodonta) demissa Meek, 1868. Trans. Chicago Acad. Sci., vol. i, p. 87, figs. 6a-c. Strophodonta demissa Nicholson, 1873. Pal. Prov. Ontario, p. 65. demissa Whitfield, 1883. Geol. of Wisconsin, vol. iv, p. 327, pl. xxv, fig. 18. This species in New York occurs throughout the Devonian. It has also been found in Illinois, Iowa, and to the far Northwest, in the Mackenzie River Basin In the Eureka District it is restricted, as far as known, to the Lower Devonian horizon. The specimens are below the average size of those from the Hamilton Group of New York, corresponding in this respect to the Upper Helderberg form; they are also more finely striated. Formation and localities —Lower horizon of the Devonian limestone, midway of Gray’s Cation, Eureka District, and at Lone Mountain, 18
miles northwest of Eureka, Nevada.
Strophodonta Patersoni Hall.
Strophomena (Strophodonta) patersoni Hall, 1857. Tenth Ann. Rep. N. Y. State Cab. Nat. Hist., p. 114. ,
Strophomena Patersoni? Billings, 1861. Can. Jour., vol. vi, p. 340, fig. 115.
Strophodonta patersoni Hall, 1867. Pal. N. Y., vol. iv, p. 89, pls. xii, xiii.
Strophomena Patersoni Nicholson, 1873. Pal. Prov. Ontario, p. 67.
There is but one specimen of the ventral valve of this species in the collection, but its depressed convex form, arching wrinkles between the coarser striz, and the fine intermediate radiating strie give it all the promi- nent characters of the species. In New York and Canada, S. Patersoni is an Upper Helderberg species, not being known in the Hamilton or Chemung Groups. Its horizon in New York and Canada is the equivalent of the Lower Devonian horizon in the Eureka District.
Formation and locality—Devonian formation, lower horizon, Lone Mountain, 18 miles northwest of Eureka, Nevada.
120 PALEONTOLOGY OF THE EUREKA DISTRICT.
Strophodonta inequiradiata Hall.
Plate 11, figs. 11, 1la.
Strophomena (Strophodonta) inequiradiata Hall, 1857. Tenth Ann. Rep. N. Y. State Cab. Nat. Hist., p. 113, inequistriata Billings, 1861. Can. Jour., vol. vi, p. 338, fig. 113. Ibid., Geology of Canada, 1863, p. 367, fig. 375. Strophodonta inequiradiata Hall, 1867. Pal. N. Y., vol. iv, p. 87, pls. xi, xii, xiii. Strophomena inequiradiata Billings, 1874. Pal. Foss., vol. ii, pt. 1, p. 24.
This species is closely allied to S. Patersoni, as is shown by a series of specimens from the Upper Helderberg Group of New York. The Nevada specimens, however, represent the well-marked characters of each species, so that there is little danger of mistaking one for the other. They occur at the same stratigraphic horizon, but in localities 15 miles distant from each other.
Formation and locality—Lower horizon of the Devonian limestone, Comb’s Peak, Eureka District, Nevada.
Strophodonta perplana Conrad (Sp.).
Plate xiii, fig. 11.
Strophomena perplana Conrad, 1842. Jour. Acad. Nat. Sci. Philad., vol. viii, p. 257, pl. xiv, fig. 11.
pluristriata Conrad, idem., p. 259.
delthyris Conrad, idem., p. 258.
crenistria Hall, 1843. Rep. Fourth Geol. District New York, p. 171.
nervosa Hall, idem., p. 266, fig. 1.
Strophodonta fragilis Hall, 1857. Tenth Ann. Rep. N. Y. State Cab. Nat. Hist., p. 143, fragilis Hall, 1858. Geol. Rep. Iowa, vol.i, pt.2, p. 496, pl. iii, figs. 6 a—-c.
Strophomena perplana Billings, 1861. Can. Jour., vol. vi, p. 343.
Strophodonta perplana Hall, 1867. Pal. N. Y., vol. iv, pp. 92, 98, and 113, pls. xi, xiii, xvii, and xix.
Strophomena perplana Nicholson, 1873. Pal. Prov. Ontario, p. 64.
.
This well-marked species ranges from the lower horizon to nearly the summit of the Devonian limestone. It is represented by a number of speci- mens which, although somewhat imperfect, exhibit the general outline, slight convexity, and fine surface strize of the ventral valve, as also the large flabel- liform divaricator muscular impressions. In New York it is found to pass
FOSSILS OF THE DEVONIAN. 121
from the Upper Helderberg through the Hamilton and into the Chemung Group. Its geographic range also includes the Province of Ontario, Can- ada, and the States of Illinois and Iowa.
Formation and localities —Devonian limestone, Comb’s Peak and Newark
Mountain, Eureka District; Lone Mountain, 18 miles northwest of Eureka, Nevada.
Strophodonta punctulifera Conrad (sp.) Plate xiii, fig. 10.
For list of synonyms and remarks, see Paleontology of New York, vol. iii, p. 188; vol. iv, p. 95; Pal. Province of Ontario, p. 68.
This species has usually been considered a Lower Helderberg form, although, as stated by Professor Hall, Mr. Billings, and Professor Nicholson, it is closely allied to, if not identical with S. ampla, of the Upper Helder- berg and Hamilton Groups. The Nevada specimens show a convex dorsal valve, slightly concave about the umbo, with strong radiating striz and punctate surface, the latter showing where the surface is covered with fine concentric strize. The Nevada shell is not referable to 8. ampla, as found in New York, and as it approaches S. punctulifera very closely the reference is made to that species.
Formation and locality—-Lower horizon of the Devonian limestone, Lone Mountain,-18 miles northwest of Kureka, Nevada.
Strophodonta arcuata Hall ?
Strophodonta arcuata Hall, 1858. Geol. of Iowa, vol. i, pt. 2, p. 492, pl. ili, figs. 1 a-e 2a, b,e, f. Calvin, 1878. Bull. U. S. Geol. Survey, vol. iv, p. 728.
A comparison with specimens from Rockford, lowa shows the Nevada shell to be less convex than the average examples, but not less so than some. It agrees otherwise in nearly every particular.
Formation and locality—Devonian limestone, south spur of Atrypa Peak, Eureka District. Nevada.
122 PALEONTOLOGY OF THE EUREKA DISTRICT.
Strophodonta Calvini Miller. Plate xiii, fig. 6. Strophodonta quadrata Calvin, 1878. Bull. U. S. Geol. Survey, vol. iv, p. 728. Not of Swallow, 1860. Trans. St. Louis Acad. Sci., vol. i, p. 639. Calvini Miller, 1883. Cat. Amer. Pal. Foss., 2d ed., p. 298.
The author describes this species as follows:
“Shell small, concavo-convex, quadrate in outline. Cardinal extremi- ties sometimes abruptly produced, sometimes rounded. Ventral valve very convex, flattened on the umbo and descending rapidly to the lateral and frontal margins. Dorsal valve concave, following closely the curvature of the other. Hinge area common to both valves, wider on ventral, finely striated. Foramen only sufficiently developed to receive the extremities of the bifid cardinal process. Muscular scars faintly impressed, not definitely bounded.
" “Surface of ventral valve ornamented by fine radiating striz. From three to five very small strize are implanted between pairs of more promi- nent, but very slender, filiform, and often slightly interrupted ones. A broad, shallow mesial sinus sometimes occupies the front half of the valve. On the dorsal valve the strize are subequal, corresponding to the finer ones of the ventral valve.
“Length, 9™"; width, 11™"; convexity, 5™™.”
The species occurs in the Devonian formation of Iowa and corresponds, from the description, very closely with the Nevada form. The latter is pro- portionally a little broader and slightly convex on the umbo, but does not appear to differ specifically.
Formation and l6calities—Lower horizon of the Devonian limestone, Lone Mountain, 18 miles northwest of Eureka, and Comb’s Peak, Eureka District, Nevada.
Genus CHONETES Fischer.
It is difficult to determine the specific relations of many of the forms of the Productide and especially those belonging to the genus Chonetes, as the shells are usually small and depend largely on the surface characters and the presence of the cardinal spines for their specific determination.
FOSSILS OF THE DEVONIAN. 123
These features are usually more or less obscured by the complete or partial exfoliation of the shell, even if it has escaped being worn or macerated previous to being embedded in the sediment. The varying conditions of preservation, if in a pure limestone, calcareous or argillaceous shale, or in an arenaceous rock, also materially complicate the question of the identity of species from various horizons and widely separated localities. The identifications between the Nevada and New York specimens of the same species were made with the above conditions in view and on a direct com- parison with authentic specimens in the Hall collection at the American Museum of Natural History in New York City, most of which were used in the original diagnoses of the various species.
Chonetes hemispherica Hall.
Chonetes hemispherica Hall, 1857. Tenth Ann. Rep. N. Y. State Cab. Nat. Hist., p. 116, and Pal. N. Y., vol. iv, p. 118, pl. xx, fig. 6, 1867. hemispherica Billings, 1861. Can. Jour., vol. vi, p. 349. Nicholson, 1873. Pal. Prov. Ontario, p. 75. Compare Strophomena gibbosa Conrad.
The types of this species are from the Schoharie grit and Corniferous limestone of the Upper Helderberg Group of New York. It is a strongly marked form, and with the exception of the closely allied C. arcuata, from the Corniferous limestone, it is not likely to be confused with any other species from the Devonian. The Nevada specimens have the same ventri- cose or subhemispheric ventral valve, with its prominent umbo rising above the hinge line. The surface is largely exfoliated from all the specimens in the collection, but sufficient remains to exhibit the characteristic radiating strie. As far as yet known it is confined to the Lower Devonian, and is associated with other well-defined Upper Helderberg forms, viz: Productus (P.) navicellus, P. (P.) truncatus, Spirifera raricosta, ete.
Among the collections of the Fortieth Parallel Exploring Expedition there is a specimen of this species from the summit of Cave Cation, Pitton Mountains, Nevada.
Formation and locality—Lower horizon of the Devonian limestone, Lone Mountain, 18 miles northwest of Eureka, Nevada.
124 PALEONTOLOGY OF THE EUREKA DISTRICT.
Chonetes deflecta Hall. Plate ii, figs. 8, 8 a, b. Ohonetes deflecta Hall, 1857. Tenth Ann. Rep. N. Y. State Cab. Nat. Hist., p. 149. gibbosa Hall, 1857. Ibid., p. 145. deflecta Hall, 1867. Pal. N. Y., vol. iv, p. 126, pl. xxi, figs. Ta-g, 8a-c.
The shells referred to this species are from the Upper and Lower De- vonian beds, and in size, general form, convexity and surface markings are specifically identical with the examples of the species from the Hamilton Group of New York. There is considerable difference in the height and width of different shells, and also in the strength of the radiating surface strie. In the latter variation Chonetes acutiradiata Hall is directly connected with C. deflecta, as expressed in its more transverse forms. Some of the more coarsely striated examples approach C. mucronata, but not sufficiently so to be identified with that species.
Its vertical range is from the Lower Devonian=Upper Helderberg Group of New York, to the Upper Devonian=Chemung Group of New York.
Formation and localities.—Lower horizon of the Devonian limestone,
Comb’s Peak, west slope of County Peak, and lower beds at Lone Mount- ain, 18 miles northwest of Eureka, Upper Devonian of Rescue Hill, Eureka District, Nevada.
Chonetes mucronata Hall?
Strophomena mucronata Hall, 1843. Geol. Rep. Fourth District New York, p 181 and p. 180, fig. 3. Chonetes laticosta Hall, 1857. Tenth Ann. Rep. N. Y. State Cab. Nat. Hist., p. 119. mucronata Hall, 1867. Pal. N. Y., vol. iv, p. 124, pls. xx, xxi. Nicholson, 1873. Pal. Prov. Ontario, p. 74.
Professor Hall gave the specific designation C. Jaticosta to a small, gib- bous, coarsely striated shell from the Upper Helderberg and Hamilton Groups of New York, which he subsequently considered as a variety of Chonetes mucronata. With this form the Nevada specimens are identified, as none of the larger, more finely striated examples are yet known from the Rocky Mountain area.
FOSSILS OF THE DEVONIAN. mato?
The largest specimens from Nevada have a length of 4"™, anda width of 6™™, the ventral valve being strongly convex or gibbous and marked by from eighteen to twenty-two strong striz. There is only one cardinal spine preserved; this is bent down and directed outward subparallel to the cardinal margin.
The specific identification is made with hesitation, as the specimens are somewhat imperfect, and the large adult shells are not present in the collections from Eureka; still the facts in favor of the identification appear to be much stronger than those against it.
Formation and locality—In the upper beds of the Devonian limestone of the foothills east of Sentinel Mountain and the Sugar Loaf, Eureka District, Nevada.
Chonetes setigera Hall.
Strophomena setigera Hall, 1843. Geol. Rep. Fourth District of New York, p. 180, fig. 2. Chonetes setigera Hall, 1857. Tenth Ann. Rep. N. Y. State Cab. Nat. Hist., p.150. Hall, 1867. Pal. N. Y., vol. iv, p. 129, pl. xxi, fig. 2; pl. xxii, figs. 1-0.
This species is associated with the preceding in the same hand speci- mens of limestone. Of its occurrence in the Marcellus shale, Professor Hall says: ‘This species occurs in the same black shale with C. mucronata, and may be distinguished from it by the more numerous and more fre- quently bifurcating striae, which are likewise more angular. ‘The direction of the cardinal spines, when present, is always a characteristic feature.”
This comparison is equally accurate when applied to the Nevada speci- mens, as the specific characters are similar in the eastern and western shells. Professor Hall gives Meadville, Pennsylvania, as the locality where it is found in the Chemung Group, thus showing its range upward from the base of the Hamilton Group. As far as known, it occurs only in the upper beds of the Devonian, in the Eureka District.
Formation and locality——In the upper beds of the Devonian limestone of the foothills east of Sentinel Mountain and the Sugar Loaf, Kureka Dis- trict, Nevada.
126 PALEONTOLOGY OF THE EUREKA DISTRICT.
Chonetes macrostriata, n. sp. Plate ji, fig. 13; pl. xiii, figs. 14, 144-0.
Shell varying in form from tranverse, subelliptical, length and breadth as 2 to 3, to subsemicircular, the length and breadth as 3.5 to 4. Hinge- line a little shorter than the greatest width, in both young and old shells. Cardinal angles obtuse.
Ventral valve varying from moderately convex, in young shells, to very convex or gibbose in the older ones. This difference in convexity is also shown in older shells of the same general size, the more narrow indi- viduals being much more convex. The outline of the valve presents the greatest convexity on the umbo, the curvature to the front and lateral mar- gins being regular, while it is more rapidly depressed towards the somewhat flattened cardinal extremities; a feature noticeable in the younger shells and strongly developed in the adults. Dorsal valve more or less conform- able in curvature to the opposite valve.
Surface marked by strong, rounded striz, the spaces between them being less than their width. They increase by intercalation and bifurca- tion, a shell 15™™ in breadth having twenty on the lower part, and one 40™™ broad forty, the striz on each having slight undulations in their course. No traces of concentric strize are to be seen.
The cardinal margin of the ventral valve in the younger shells shows five or six small oblique spines on each side of the apex that in the older shells are not visible in any specimens in the collection. The ventral area is narrow, linear, and has a rather small foramen midway that is partially closed by the cardinal process of the opposite valve. Dorsal area very narrow.
The imperfect cast of the ventral valve shows a bilobed apex, formed by the diverging dental lamella and narrow median ridge, the muscular impressions being obscured by adhering fragments of the shell. The por- tions of the surface of the interior of this and the dorsal valve that are shown in the specimens are finely papillose, the papillz of the dorsal valve being somewhat coarser than those of the ventral.
The variation between the young and adult individuals of this species
FOSSILS OF THE DEVONIAN. 127
is so great that the two extremes will readily be taken as distinct species, to avoid which an illustration is given of the younger and older shells with an intermediate form. The outer surface of the ventral valve of the shell is exfoliated, the characteristic striz showing on the dorsal valve of the same specimens
Formation and localities—Lower horizon of the Devonian limestone, Comb’s Peak; ‘south spur of Atrypa Peak; ‘on the divide of the Reese and Berry Cafion, and midway of Gray’s Canon, Eureka District, Nevada; also at the same horizon at the north end of the Ravens Nest, Pinon Range, Nevada.
Chonetes filistriata, n. sp.
Plate xiii, figs. 15, 15a.
Shell transverse, broadly subelliptical, varying in proportion from 4 to 8, to 3 to 2, in breadth and length, respectively; the hinge-line is a trifle shorter than the greatest width of the shell, and the cardinal angles are ex- tended in very short auriculate points.
Ventral valve moderately convex, the convexity varying but slightly between the young and old shells; the outline of the valve is regularly convex, rising from the cardinal margin and sloping more rapidly from the broad central portion towards the front and lateral margins; cardinal margin with three or more short, slightly oblique spines on each side of the apex. The area is narrow, linear, and divided midway by a rather broad triangular foramen that is nearly filled by the cardinal process of the opposite valve.
The dorsal valve is moderately concave, following very nearly the curvature of the ventral valve. Area linear and very narrow.
Surface marked by numerous fine, closely arranged striz, that increase by intercalation and bifurcation; they extend to nearly the hinge line on the cardinal extremities, and vary in number from 80 to 90 on the lower portion of a medium-sized shell. A few specimens show faint undulating concentric striz.
The specimens are all preserved in a shaly limestone and the interiors of the valves have not been observed.
Numerous shells corresponding in general form and size with this spe-
128 PALEONTOLOGY OF THE EUREKA DISTRICT.
cies occur at the same locality a few feet higher in the strata. Their sur- face, however, is smooth, or shows traces of very fine striz, a feature pro- duced probably by maceration or the smoothing of the shell by attrition during the life of the animal.
Of the Devonian species of Chonetes from the Devonian of the Missis- sippi Basin or New York, C. coronata Conrad (See Pal. N. Y., vol. iv, p. 133), is most nearly related to this in general form. It differs materially in the coarser surface markings, more oblique cardinal spines, smaller ventral foramen, and greater convexity.
Formation and locality—Lower horizon of the Devonian limestone, Comb’s Peak, Eureka District, Nevada.
Genus PRODUOTUS Sowerby. Subgenus PRODUCTELLA Hall, 1867. Productus (Productella) subaculeatus Murch. Plate vii, fig. 2, pl. xiii, figs. 19, 19a, 20, 20a.
For list of synonyms see Davidson’s Monograph of British Devonian Brachiopoda, p. 99, and Pal. N. Y., vol. iv, p. 154.
The figures given by Murchison of the type of this species” might have been taken from specimens from the Eureka District, so close is the simi- larity between the forms from the two widely separated localities. ‘There -are some slight variations in larger specimens but hardly sufficient to indi- cate a varietal distinction in a species of a genus subject to so many and wide departures from what may be considered the types of some of its most typical species.
The illustrations given in the fourth volume of the Paleontology of New York, plate xxiii, are of smaller shells than those from Nevada, but ap- pear to be specifically identical with them, while the four referred to this species, with a query, from the Devonian limestone of Nevada (Geol. Expl. Fortieth Parallel, vol. iv, p. 36), are evidently referable to a variety of Hall’s P. (P.) Shumardianus.
Professor Hall identifies P. (P.) subaculeatus in the Upper Helderberg
Bull. de la Soe. Geol. de France, vol. xi, p. 255, pl. ii, figs. 9a, b, ec.
FOSSILS OF THE DEVONIAN. 129
limestone, and states that he does not know of its occurrence in the Hamil- ton and Chemung Groups of New York.
In Europe it has a wide vertical range in the Devonian formation, and its geographic range is very great.
There appears to be considerable confusion in regard to the relations of this species and P. (P.) Shumardianus of Hall, and also with several European forms that have been identified with it. There can hardly be any doubt of the identity of the specimen figured on plate xiii, figs. 20, 20a, the one given by Murchison in his original description of the species, and the adjoining figures, 19, 194, of the Nevada specimen which is associated in the same layer of rock with specimens which unite it, by a series of examples, with the typical forms of P. (P.) Shumardianus as they occur in the Burling- ton sandstone of Iowa. At present it is not practicable to give the neces- sary illustrations to show the passage from this species to several forms now considered as distinct, but it is anticipated that the opportunity will be af- forded in the future and that larger collections will be accessible from the Devonian of the Rocky Mountain region.
Formation and localities —Lower, middle, and upper horizons of the _ Devonian limestone, west slope of County Peak; Rescue Hill; mouth of ‘Packer Basin, and at The Gate northwest of Eureka, Eureka District, Nevada.
Productus (P.) subaculeatus also occurs in the Lower Carboniferous of the Eureka District.
Productus (Productella) Shumardianus Hall. Plate xiv, fig. 1.
Productus snumardianus Hall, 1858. Geol. Rep. Iowa, vol. i, pt. 2, p. 499, pl. iii, fig. 9; pl. vii, fig. 1. spinulicoste (in part) Hall, 1857. Tenth Ann. Rep. N. Y. State Cab. Nat. Hist., p. 173. concentricus Hall, 1857. Tenth Ann. Rep. N. Y. State Cab. Nat. Hist., p. 180; Geol. Rep. Iowa, vol. i, pt. 2, p. 517, pl. vii, fig. 3. pyxidatus (partim vel totum) Hall, 1858. Geol. Rep. Iowa, vol. i, pt. 2, p. 498, pl. 3, figs. 8a-—e. Productella shumardiana Hall, 1867. Pal. N. Y., vol. iv, p. 157, pl. xxiii, figs. 6-8.
With the views expressed in relation to this species, in the remarks on P. (P.) subaculeatus, it is unnecessary to state why they are considered as 9CDW
130 PALEONTOLOGY OF THE EUREKA DISTRICT.
closely allied and probably identical species. This form ranges throughout the Devonian limestone of the district and occurs in the lower beds at Lone Mountain, 18 miles northwest of Eureka.
The variety P. (P.) pyxidatus is found in both the lower and upper beds. It does not appear to be specifically distinct from the form referred to P. (P.) Shumardianus.
Productus (Productella) Hallanus, n. sp. Plate xiii, figs. 17, 17a.
Productus dissimilis Hall, 1858. Geol. Rep. Iowa, vol. i, pt. 2, p. 497, pl. iii, figs. 7a-e. dissimilis Meek, 1868. Trans. Chicago Acad. Sei., vol. i, p. 91, pl. xiii, fig. 3. Not Productus dissimilis De Koninck, 1846.
Shell semielliptical or suborbicular, with the length and breadth usually nearly equal, although in some instances it is transversely ellipti- cal. Hinge line shorter than the greatest width of the shell
Ventral valve strongly convex, ventricose on the upper part, which projects slightly over the hinge line at the umbo and terminates in a slightly incurved beak; the sides are a little depressed towards the somewhat auric- ulate cardinal extremities. Area extremely narrow and rarely seen even on well preserved shells. Dorsal valve concave, following the curvature of the opposite valve.
Surface of ventral valve marked by fine radiating strize that are slightly irregular in their course, as if deflected by the few scattered, scarcely per- ceptible spine bases. The dorsal valve shows no radiating striz, but strong subimbricating, concentric lines give a striking appearance in constrast with the radiating striee of the ventral valve.
The type specimens of Professor Hall’s P. (P.) dissimilis were from the Hamilton Group, at or near Rockford, Iowa, and present all the char- acters mentioned in the above description, which was drawn from the Nevada specimens. The specific identity of the two forms is very close, and does not permit of a separation on any differences presented by the specimens now before me. As the name given by Professor Hall was pre- occupied by a species of the same generic relations from the Devonian
FOSSILS OF THE DEVONIAN. 131
rocks of Belgium, a new specific designation is given in honor of the origi- nal discoverer of the species
Formation and localities.—Lower and upper horizons of the Devonian limestone, west slope of County Peak, and Rescue Hill, Eureka District, Nevada.
Productus (Productella) navicella Hall. Plate xiii, fig. 9.
Productus navicella Hall, 1857. Tenth Ann. Rep. N. Y. State Cab. Nat. Hist., p. 172. Productella navivella Hall, 1867. Pal. N. Y., vol. iv, p. 156, pl. xxiii, figs. 1-3, 9-11.
The specimens referred to this species from the Upper Helderberg and Hamilton Groups of New York are distinguished by their narrow, elon- gate form, extreme areuation, and strong costz on the lower half of the shell that are extended upward as little ridges formed by the spine bases. The specimens representing the species in Nevada are a little more elongate than the average of the New York forms, and the radiating costee are some- what stronger, otherwise the two are identical.
Formation and locality—Lower horizon of the Devonian limestone, south ridge of Atrypa Peak, Eureka District, Nevada.
Productus (Productella) truncatus Hall. Plate xiv, fig. 2.
Productus truncatus Hall, 1857. Tenth Ann. Rep. N. Y. State Cab. Nat. Hist., p. 171. Strophomena pustulosa Hall, 1843. Geol. Rep. Fourth District New York, p. 18. Productella truncata Hall, 1867. Pal. N. Y., vol. iv, p. 160, pl. xxiii, figs.12-24. Not Productus pustulosus Phillips.
This pretty little species occurs in the Lower Devonian beds, and pre- sents the characters of the specimens from the Marceilus shale of New York.
In his remarks on this species, Professor Hall states that, on the author- itv of M. de Verneuil, Strophomena pustulosa, a species founded apparently on a dorsal valve of this species, has been referred to Productus (Stropha- losia) Murchisonianus M. de Koninck, which is likewise regarded as iden- tical with’ the species Professor Hall described as Productus Shumardianus. Professor Hall has shown that P. (P.) truncatus possesses features not ob-
Bi, PALEONTOLOGY OF THE EUREKA DISTRICT.
served in P. (P.) Shumardianus, and, as it occurs in Nevada, it is very distinct from the young shells of the latter species. It approaches much more nearly P. (P.) navicella, with which it is associated, differing from that very decidedly in its truncated apex, much less arcuate ventral valve, and broader, less elongate outline. With Productus Murchisonianus it appears to present but very few characters in common.
Formation and localities—Lower horizon of the Devonian limestone, south ridge of Atrypa Peak, and west slope of County Peak, Eureka Dis- trict, Nevada.
Productus (Productella) lachrymosus var. limus Conrad (Sp.). Plate xiii, figs. 18, 18a. Strophomena lima Conrad, 1842. Jour. Acad. Nat. Sci. Philad., vol. viii, p. 256. Productella lachrymosa var. lima Hall, 1867. Pal. N. Y., vol. iv, p. 174, pl. xxv, figs. 29-32.
This variety of P.(P.) lachrymosus is well represented by specimens from the summit of the Devonian limestone at The Gate, where it is associated with P. (P.) subaculeatus and P. (P.) lachrymosus var. stigmatus. The median depression of the ventral valve and the characters of the spiniferous tuber- cles are distinctly marked, as also the general form and size of the shell.
Formation and locality—Devonian limestone, at The Gate, northwest of Eureka, Nevada.
Productus (Productella) lachrymosus, var. stigmatus Hall.
Productella lachrymosa var. stigmata Hall, 1867. Pal. N. Y., vol. iv, p. 174, pl. xxv, figs. 33-41. Compare Productus? Meek, 1868. Trans. Chicago Acad. Sci., p. 92, pl. xiii, fig. 5. This strongly marked variety is represented by a fine series of speci- mens that present it as found in the Chemung Group of New York and also pass towards a more costate variety that, in this respect, draws near the true species P. (P.) lachrymosus, but in size and general appearance it is more nearly related to the var. stigmatus. The coste or plications are not formed by the elongation of the spine bases but by the plication of the shell, and
FOSSILS OF THE DEVONIAN. 133
present various stages of development, from a simple trace on the front margin to where they pass up over the center.
The form from the Mackenzie River Basin, illustrated by Mr. Meek and not specifically identified, is very closely related to the semicostate variety, if not identical with it, and it occurs in association with Rhynchonella castanea, a form found with P. (P.) lachrymosus vay. stigmatus, at Rescue Hill.
Formation and localities—Upper horizon of the Devonian limestone, Rescue Hill, and The Gate, northwest of Eureka, Nevada.
Productus (Productella) speciosus Hall. Plate xiii, fig. 8.
Productus speciosus Hall, 1857. Tenth Ann. Rep. N. Y. State Cab. Nat. Hist., p. 176. Productella speciosa Hall, 1867. Pal. N. Y., vol. iv, p. 175, pl. xxv, figs. 1-11.
This beautifully marked species occurs in the same beds with the vari- eties of P. (P.) lachrymosa, but it is so distinctly.characterized by a narrow, somewhat attenuate umbo and the closely arranged smaller and more numer- ous spiniferous tubercles that there is little danger of confounding the two species. Of the identity of the New York Chemung Group specimens and those from the Eureka District there is hardly an opportunity to suggest a point in opposition, as they closely coincide in all their specific characters.
Formation and localities —Upper horizon of the Devonian limestone, Rescue Hill, and at The Gate, northwest of Eureka, Nevada. =
Productus hirsutiforme, n. sp. Plate ii, figs. 10, 10a.
Shell thin, transversely semicircular; width less than the length, unless distorted by compression; hinge line equaling or a little less than the width of the shell.
Ventral valve moderately convex and without median sinus, rather abruptly depressed toward the cardino-lateral margins, which are flattened and broadly auriculate; beak small, incurved. Dorsal valve concave and following the curvature of the ventral one.
134 . PALEONTOLOGY OF THE EUREKA DISTRICT.
Surface marked by closely arranged, slightly undulating, concentric strie and slight undulating ridges of growth in some examples. A few slen- der curved spines are scattered irregularly over the surface. ;
The interior of the ventral valve is minutely papillose throughout; other interior characters unknown.
It is with hesitation that a new specific name is given to a species of this genus, owing to the range of specific variation within it. As indicated by the name, the species is related to P. hirsuta Hall of the Chemung Group of New York. It differs in the surface characters. It has a few minute scattered spines on a comparatively smooth surface, while P. hirsuta has fine spines with elongate bases over the entire surface, and also a row of long spines near the cardinal border.
Formation and localities —Upper Devonian, White Pine shale, on the south slope of Diamond Peak, Eureka District, and also at the same geologic horizon throughout the shale on the east side of Applegate Canon, White Pine Mining District, Nevada.
Genus SPIRIFERA Sowerby. Spirifera disjuncta Sowerby, 1840.
Synonyms: See Davidson’s Monograph of British Devonian Brachiopoda, and Paleon- tology of New York, vol. iv, p. 243. To this there may be added: Spirifera Norwoodi Meek, 1860. Proc. Acad. Nat. Sci. Philad., vol. xii, p. 308 (not 8. Norwoodi Hall). 4 Utahensis Meek, 1860. Note appended to extra copies of above cited paper. Kennicotti Meek, 1868. Trans. Chicago Acad. Nat. Sci., vol. i, p. 101, pl. xiv, fig. 9. Utahensis Meek, 1876. Rep. Expl. Great Basin of Utah, Simpson, p. 345, and Geol. Expl. Fortieth Par., 1877, vol. iv, p. 39, pl. ili, figs. La-e.
The types of Mr. Meek’s Spirifera Utahensis were collected at The Gate, northwest of Eureka, and cited as coming from a dark limestone of Devonian age, in longitude 115° 26’ W., latitude 39° 30’ N., a locality named Swallow Canon by Captain Simpson, and now known as The Gate. From this locality a number of very perfect specimens were obtained by the Eureka Survey. They exhibit the narrow, rotund form, and also the short form with extended lateral angles. The examples of the species used
FOSSILS OF THE DEVONIAN. 1535)
by Mr. Meek were small, but do not differ from specimens of the same size found at Newark Mountain or specifically from the larger shells that are identical with examples of the species found in New York and also in Eng- land.
Formation and localities.—Central and upper portions of the Devonian limestone, Newark Mountain, and at The Gate, northwest of Eureka, Ne- vada.
Spirifera raricosta Conrad (Sp.). Plate iv, figs. 2, 2a; pl. xiv, fig. 12. Delthyris raricosta Conrad, 1842. Jour. Acad. Nat. Sci. Philad., vol. viii, p. 262, pl. xiv, fig. 18. undulatus Vanuxem, 1842. Geol. Rep. Third District New York, p. 132, fig. 3. Spirifera raricosta Billings, 1861. Can. Jour., vol. vi, p. 258, figs. 71-73 of p. 259; Pal. Fossils, 1874, vol. ii, pt. 1, p. 47, pl. 3A, figs. 5, 5 a, b. Hall, 1867. Pal. New York, vol. iv, p. 192, pl, xxvii, figs. 30-34, pl. xxx, figs. 1-9. Nicholson, 1873. Pal. Prov. Ontario, p. 82.
A species closely allied to this, if not identical, occurs in the lower fossiliferous horizon of the Devonian limestone. It differs in not having quite as distinct concentric striz, and also in the absence of the prominent septum shown in casts of the ventral valve of specimens from the Schoharie erit of New York. These are characters that are variable in the New York forms, and do not afford data for the establishment of a distinct peo: on the examples thus far obtained in Nevada.
At the East this species ranges through the Schoharie grit and Cor- niferous limestone of the Upper Helderberg Group, and its known geo- graphical extension carries it west from New York across the State of Ohio to Southern Indiana and northwest into Canada West.
A larger series of specimens from Lone Mountain, collected a year after the above was written, show a gradation in form from Spirifera rari- costa to S. duodenaria, the constant differences in the median sinus and fold alone serving to distinguish, in external characters, the two species.
Formation and localities—Lower horizon of the Devonian limestone, Comb’s Peak, Eureka District, and Lone Mountain, 18 miles northwest of Eureka, Nevada.
136 PALEONTOLOGY OF THE EUREKA DISTRICT.
Spirifera varicosa Hall.
Spirifer varicosus Hall, 1857. Tenth Ann. Rep. N. Y. State Cab. Nat. Hist., p. 130. Ibid., Description of New Pal. Fossils, p. 90, 1857. Spirifera varicosa Hall, 1867, Pal. New York, vol. iv, p. 205, pl. xxxi, figs. 1-4.
Ventral valve transverse, semielliptical; length less than one-half the width, lateral extremities pointed; strongly convex, most prominent on the umbo; mesial sinus strongly defined, rounded on the bottom and continued to the apex of the beak; beak narrow and slightly incurved. Area equal to one-half the width of the valve; it is flat below and a little concave towards the apex; the fissure is high and large.
Surface marked by eight or nine simple, slightly angular plications on each side of the mesial sinus, and with fine radiating striz near the umbo, where the only fragment of the outer surface is preserved, the remaining portions having been entirely exfoliated; traces of strong concentric striz, however, are seen on the lower part of the cast.
The species represented by this single valve, is a member of a group of species illustrated by Spirifera varicosa, S. segmenta, and S. arctisegmenta, in the Upper Helderberg limestones of the Falls of the Ohio, and in New York State. It is related to S. varicosa by the general form, the size of the area and foramen, and the number of surface plications, and also the fine radiating strize near the umbo; but, in the absence of the strong varicose concentric striz, a striking difference exists between them. In the character of the plications the agreement is with S. arctisegmenta, but the latter has a very narrow foramen and the area bending forward, features that lead to making a provisional reference to the former species, as they are considered as of more importance than the development of the surface striz; besides. the Nevada shell shows traces of strong concentric striz: on the cast, and a large series of specimens would probably exhibit considerable variation in this respect. In this event, or should it prove to be a distinct species, it adds another member, by its general character, to the group of forms uniting the fauna of the Lower Devonian of Nevada and that of the Upper Helderberg Group east of the Rocky Mountain region.
Formation and locality—Lower portion of the Devonian limestone, at. Lone Mountain, 18 miles northwest of Eureka, Nevada.
FOSSILS OF THE DEVONIAN. L3G
Spirifera Parryana Hall? Plate xiv, fig. 10. Spirifer parryanus Hall, 1858. Geology of Lowa, vol. i, pt. 2, p. 509, pl. iv, figs. 8a, b. Parryana Billings, 1861. Can. Jour., vol. vi, p. 261, figs. 77, 78.
The original type of this species is from the Hamilton Group of Iowa. In all essential specific characters the ventral valve of the Nevada shell, the only portion discovered, is similar to that of the Iowa type, differing mainly in the absence of the fine concentric striz crossing the radiating strie. Each of these features, the simple radiating striae and the concentric stri, occur on different specimens of an allied species, S. mesastrialis, of the Chemung Group of New York. The finding of entire shells may afford specific distinctions not known at present, but with the present specimens, the identification is made with S, Parryana.
A specimen collected by the geologists of the Fortieth Parallel Geo- logical Survey, labeled “‘ Pinon Range,” is larger than the Kureka specimens, but otherwise agrees with the specimen illustrated.
Formation and locality—Devonian limestone, on the divide at the head of the Reese and Berry Cation, Eureka District, Nevada.
Spirifera (sp. und’t.).
This species is allied to the group represented by Spirifera Manni, of the Upper Helderberg Group of New York and Ohio. The ventral valve is subpyramidal, the height nearly equaling one-half the length. Apex slightly projecting over the area. Mesial sinus well-defined, reaching to the apex. Area elevated, slightly concave above; fissure open to the apex, about twice as long on the sides as the width at the base.
Surface marked by. six or seven subangular or rounded plications on each side of the median sinus. Finer surface markings unknown, owing to the exfoliation of the shell.
Owing to the fact that species of this genus undergo great variations, and that our material is unsatisfactory, no specific reference is made of this shell.
Formation and localities—Devonian limestone, Comb’s Peak, Eureka District, and Lone Mountain, 18 miles northwest of Kureka, Nevada.
138 PALEONTOLOGY OF THE EUREKA DISTRICT.
Spirifera Englemanni Meek.
Spirifera Englemanni Meek, 1860. Proc. Acad. Nat. Sci. Philad., vol. xii, p. 308. Meek, 1876. Rep. Expl. Great Basin of Utah (Simpson), p. 346, pl. i, figs. la-e. (Not S. Englemanni, M. & W.) Meek, 1877. Rep. Geol. Expl. Fortieth Par., vol. iv, p. 41, pl. ili, figs. 3a-e.
The original specimens of this species were found at The Gate, north- west of Eureka, by Colonel Simpson’s exploring party, and subsequently Mr. Arnold Hague obtained examples from the White Pine Mountains south- east of the Eureka District.
The specimens in the present collection came from Newark Mountain, in the upper portion of the Devonian limestone, and present the essential characters given by Mr. Meek in his description of the species.
Spirifera Pinonensis Meek. Plate iv, figs. 1, la-f. Spirifer (Trigonotreta) Pinonensis Meek, 1870. Proc. Acad. Nat. Sci. Philad., vol. xxii, p. 60. Ibid., 1877, Geol. Expl. Fortieth Par., vol. iv, p. 45, pl. i, figs. 9a, b. Spirifera (Trigonotreta) argentarius Meek, 1877. Geol. Expl. Fortieth Par., vol. iv, p. 42, pl. iv, figs. 4 a—b.
This species ranges from the base to the summit of the Devonian limestone, throughout the Eureka District, and also occurs in the Pinon Mountains, where the original types described by Mr. Meek were collected. In the White Pine Mountains the variety described as S. (7.) argentarius Meek is found in the Middle and Upper Devonian. The species S. Pino- nensis was founded on the larger, more coarsely ribbed variety. Among the large series collected in the Pinon Range a shading off into the smaller, finer ribbed form is observed, and among the still more extensive series from the Eureka District the gradation of form and characters between the type of S. Pinonensis and P. argentarius is complete.
Formation and localities —The species ranges throughout the Devonian limestone, having been found in the upper beds south of The Gate and at Newark Mountain; at the lower horizon it occurs at Comb’s Peak; Atrypa Peak; Lone Mountain, 18 miles northwest of Eureka, ete., Eureka District; also at the west base of Mount Argyle, White Pine District, Nevada.
FOSSILS OF THE DEVONIAN. 139
Subgenus MARTINIA McCoy. Spirifera (Martinia) glabra Martin.
For list of synonyms, see British Carboniferous Brachiopoda, Davidson, vol. ii, p. 59-
Spirifera M. glabra is mentioned by Mr. Davidson in his monograph of the British Carboniferous Brachiopoda, p. 62, as occurring in Devonian rocks, and he also states that he had specimens from the Devonian of Devonshire which appeared undistinguishable from those in the Carboniferous limestone. Before reading this observation we had compared the Devonian specimens from Nevada with examples of S. (JL) glabra from the Carboniferous lime- stone of England, and also with Mr. Davidson’s beautiful illustrations of the species, and concluded that they were at the most but a variety of the same species, and it is only for convenience in referring to the Nevada Devonian form that a varietal name is proposed.
Spirifera (M.) Franklini Meek, 1869 (Trans. Chicago Acad. Sci., vol. i, p. 107, pl. xiv, fig. 12), is, as mentioned by Mr. Meek, closely related to S. (M.) glabra, and with the original specimen before me to compare with the Nevada shells and Mr. Davidson’s figures of the species, it scarcely appears to be more than a variety, if even that, of S. (JL) glabra. Mr. Meek sepa- rated it from 8. (M. )glabra on account of having the lateral margins of the area of the ventral valve extending out part way parallel to the hinge mar- gins, instead of sloping regularly from the beak to the extremities of the hinge. In the variety to be next described both characters occur on the area of the ventral valve on different specimens, so that it is scarcely a good specific distinction.
Spirifera (M.) glabra, var. Nevadensis, n. var.
Plate iii, fig. 5; pl. xiv, figs. 14, 14a, b.
The range of variation among the specimens in the collection is con- siderable, as they differ in the strength and angularity of the mesial fold and sinus, and the depression along the middle of the mesial fold of the dorsal valve may be strong as in the example illustrated on plate xiv, fig. 14, or entirely absent even in large-sized specimens. Some shells are also
140 PALEONTOLOGY OF THE EUREKA DISTRICT.
much more transverse than others and the relative length of the hinge line varies.
The surface is usually smooth, owing to the condition of preservation of the shell. Examples show, however, that it was marked in some instances by obscure radiating plications, concentric striz about 1™™ distant, also fine radiating interrupted striz. These vary in different shells and in some are entirely absent.
The variety differs from the typical specimens of S. (MZ.) glabra in having the greatest transverse diameter higher up on the shell, and the mesial fold and sulcus usually more angular. It also averages smaller in size, the larg- est specimen having a height of 30", with a breadth of 38™™, and the aver- age about 25™" by 30™™.
Professor Hall compares S. (1) glabra and S. (M.) levis of the Devonian of New York, and more recently the latter has been-considered a variety of S. (IL) glabra," a reference that I would concur in, placing it, the Ne- vada variety, and Mr. Meek’s S. (M.) Franklini, from British America, as the three known representatives of the Carboniferous species in the Devo- nian rocks of the eastern and western side of the continent.
Formation and localities —Upper portion of the Devonian limestone, on the ridge east of Yahoo Canon, and on the south side of The Gate, north- west of Eureka, Eureka District, Nevada.
The above was written in 1881, as the result of the study of the spec- imens then in the collection. In the summer of 1882 I returned to the locality and obtained a number of good specimens, some of which have faintly defined radiating plications, thus showing that those represented on fig. 14), plate xiv, were not the result of irregular exfoliation of the outer shell, but a portion of the original surface. An additional figure, plate iii, fig. 5, is given of a less transverse specimen than that represented on plate xiv, figs. 14, 14a, b. This is of the same character as that of S. (L.) undifera, from the Lower Devonian, plate iii,, figs. 6, 6a. The relations of S. (JZ) glabra and S. (M.) wndifera will be spoken of in the description of the latter species.
1.8. Williams’ Life History of Spirifera levis, Ann. New York Acad. Sciences, vol. ii, 1881.
FOSSILS OF THE DEVONIAN. 141
Spirifera (M.) Maia Billings. Plate iii, figs. 1, la-e; pl. xiv, figs. 13, 134.
Athyris Maia Billings, 1860, Can. Jour., vol. v, p. 276, figs. 33, 34.
Spirifera Maia Hall, 1867. Pal. New York, vol. iv., p. 416; pl. lxiii, figs. 6-13.
Athyris (?) Maia Nicholson, 1874. Pal. Proy. Ontario, p. 88.
Compare Spirifera subumbona Hall. 1867. Pal. N.Y., vol.iv, p. 234, pl. xxxiii, figs. 22-30, S. (IL.)meristoides Meek, 1868. Trans. Chicago Acad. Sci., vol. i, p. 106, and 8. (J.) sublineatus Meek, ibid. p. 103.
Professor Nicholson considers Spirifera (M.) Maia, as identified by Professor Hall as, probably, a distinct species from Athyris Maia Billings, and refers the Canadian species to the genus Athyris, with a query.
The specimens used by Professor Hall in his determination, three of which are illustrated on plate Ixiii of vol. iv, Paleontology of New York, are now in the Hall collection in the American Museum of Natural History, New York City, and are from Saint Mary’s, Canada West, the typical lo- cality of the species. They exhibit the narrow cardinal area and small tri- angular fissure mentioned by Professor Hall, and also the variation in form from elongate to broad ovate. Mr. Billings and Professor Nicholson failed
~“toobserve the cardinal area and fissure which is frequently almost entirely concealed by the incurved beak.
The Nevada form corresponds with that from Canada West. Slight differences, liable to exist in specimens of the same species from widely separated localities, are not perceptible in the examples separated by an interval of nearly 1,800 miles, and there are no perceptible variations in form between the specimens occurring in the Lower Devonian horizon and those of the limestone beds over 3,000 feet above.
When comparing the adult shells with other species it is noticeable that the more transverse forms approach the type of Spirifera (M.) lineata, also the smooth variety of Spirifera (M.) undifera. If it were not for the large series of specimens it would not be difficult to select three allied species, but, with the intermediate forms, there is but one variable species which is closely allied to Spirifera (M.) lineata and Spirifera (IL.) planoconveaus of the Carboniferous.
There is considerable variation of form among the large number of
142 PALEONTOLOGY OF THE EUREKA DISTRICT
specimens representing the young of S. (M.) Maia in the collections from Res- cue Hill and Sentinel Mountain. Those that are broader than long, with the beak a little incurved over the high, prominent area of the ventral valve, are essentially identical with the type specimens illustrated by Professor Hall (Pal. N. Y., vol. iv, pl. xxxiii, figs. 22-30) from the Hamilton Group of New York as Spirifera (M.) subumbona. Closely resembling these come the forms described by Mr. Meek from the Devonian limestone of the Macken- zie River Basin. As described by him and illustrated (Trans. Chicago Acad. Sci., pp. 103, 106, pl. xiv, figs. 1 a—c and 2a-c), the two species S. (M.) meristoides, and S. (M.) sublineatus, appear to be identical with the New York and Nevada species. The muscular impression on the cast of the ventral valve shows the faint furrow in some specimens more deeply impressed, with the flat, shallow, lateral impressions, as in S. (M.) sublineata, and in other specimens the vascular impressions are shown, as in S. (JL) meristoides, and the form of S. (A.) meristoides is similar to that of a globose, elongate variety of S. (M.) Maia, that has the beak closely incurved. If the species are not the same they are at least very closely allied. The series of variations continue in the direction of a more elongate gibbous form, with the beak incurved over and partially concealing the low area; this feature also occurs in a broader gibbose variety, which is connected by a direct series of specimens with the Hamilton species S. (M.) subumbona. The latter, as it occurs in New York, is distinguished by the fine concentric strize and minutely punctate surface, although the shell structure appears to be fibrous. The same surface and shell structure is shown in the young shells of S.(L.) Maia. At first these were separated and referred to S. (J/.) subumbona, but the obtaining of a large number of specimens of various forms and size in association with S. (JZ.) Maia showed this separation to be a forced one. It is possible that S. (JZ) subumbona is distinct from the young of S. (M.) Maia, and until the material can be obtained to show that in the eastern Devonian the young of S. (.) Maia is identical with S. (M.) subumbona, the two specific names will have to be recognized.
Formation and localities—Devonian limestone, Rescue Hill, south slope of Sentinel Mountain, west slope of County Peak, Eureka District and Lone Mountain, northwest of Eureka, Nevada.
FOSSILS OF THE DEVONIAN. 143
Spirifera (M.) undifera Roemer. Plate iii, figs. 3, 3 a, b, 6, 6-a; plate xiv, figs. 11, 11 a, b. Spirifer undiferus Roemer, 1844. Rhein. Uebergangseb., p. 70 u. 73, tab. iv, figs. 5, 6. undiferus Schnur, 1853. Dunker’s Paleontographica, vol. ili, Brach., Hifel., p. 204, tab. xxxiv, figs. 3 a-d. Sandberger, 1855. Brach., Rhein, Schichtensystems, p. 18, pl. xxxi, fig. 8. Spirifera undifera Davidson, 1865. Mon. Brit. Devon. Brach., p. 36, pl. vii, figs. 1-10; also, var. undulata, ibid., figs. 11-14. compactus Meek, 1868. Trans. Chicago Acad. Sci., vol. i, p. 102, pl. xiv, figs. lla-d. undiferus, var. Takwanensis, Kayser, 1882. China, Richthofen, vol. iv, p. 86, tab. xi, figs. 1, 1 a-e. Compare Spirifera jimbriata (Conrad, 1842) Hall, 1867, Pal. N. Y., vol. iv, p. 214, pl. 33; also, S. subundiferus M. & W., 1868. Geol. Surv. Dlinois, vol. iii, p. 434, pl. x, figs. 5 a-e, and 8. (I.) Richardsoni Meek, 1868. Trans. Chicago Acad. Sci., vol. i, p. 104.
But one specimen of this species was found among the Devonian Brachiopods brought from the Eureka District in 1880. That differed so much from a typical specimen of Spirifera (M.) undifera, kindly sent to me by Mr. Davidson, who received it from Dr. Roemer, that I gave it a specific ame in manuscript, comparing it to S. (M.) fimbriata Conrad. During the field season of 1882 a large number of specimens were collected from the Lower Devonian of the same district that afford the means for a more extended comparison with S. (M.) undifera and S.(M.) fimbriata.
The variety shown by figs. 11, 114-2, of plate xiv (the original speci-
men found in 1880), has the beak of the ventral valve so closely incurved that the narrow area and the foramen are almost entirely concealed; the few broad, rounded plications are crossed by concentric striz, with inter- spaces between of a little over one millimeter in width; on these, between the striz, radiating interrupted strize occur that are precisely similar to those on specimens of S. (JZ.) fimbriata Conrad, now before me, from the Upper Hel- derberg Group of New York, except that they are somewhat finer. On the shells of this species from the shales of the Hamilton Group these radiating strie reach their maximum development, appearing as elongate, radiating tubercles on the interspaces between the imbricating striz. Among the Eureka specimens individuals occur that show the concentric striz about
144 PALEONTOLOGY OF THE EUREKA DISTRICT.
one-half a millimeter distant from each other, and others where they are crowded still more closely; in these we have the typical surface of S. (IL) undifera. This crowding together of the concentric striz is carried still further in S. (Z.) compacta Meek, where the radiating plications are also more numerous. No one can examine the beautiful series of forms given by Mx. Davidson on plate vii of his Monograph of Devonian Brachiopoda without observing that the range of variation in the strength and number of the plications is quite as great as between the Nevada type illustrated on plate xiv, and the British American form illustrated by Mr. Meek (Trans. Chicago Acad. Sci., vol. i, pl. xiv). The differences in the height of the area between the two last-mentioned shells is of a very decided character, but among the later collections examples occur that serve to bridge over and unite the two in this respect; one specimen has an area of the same height as the variety S. (/.) compacta (plate xiv, figs. 13 6, c), and another is inter- mediate (plate iii, fig. 5).
From Lone Mountain there is a shell of the type of S. undifera that has about twenty obscure plications on each side of the mesial fold and sinus of the ventral and dorsal valve, respectively. These are crossed by concentric strice and fine radiating interrupted striz. Still another specimen has lost all the radiating plications, and has only the concentric striz and interrupted radiating strive (plate iii, figs. 3, 3a, b). The latter shell may readily be identified with S. (M.) pramatura Hall, of the Upper Devonian of New York, or S. (1L.) pseudolineata or S. (M.) setigera of the Lower Carboniferous limestone of the Mississippi Valley. It is, however, in our opinion, a pre- cursory type in the Lower Devonian of the shell we have called S. (JZ) glaber, var. Nevadensis (ante, p. 139), and which, before the discovery of this shell without plications, in the Lower Devonian, was considered the direct lineal descendant of S. (1.) undifera. We cannot, however, fail to notice the close correspondence between the variety of S. (IL) wndifera described by Mr. Meek as S. (J.) compacta, and the Carboniferous S. (JL) pinguis Sow- erby, so fully illustrated by Mr. Davidson. S. (MZ.) Richardsoni Meek, from the Devonian of British America, is closely allied to the Lone Mountain shell having numerous radiating plications.
From these comparisons it appears that S. (IL) undiferais the type of a widely distributed and very variable species. Among the American varie-
FOSSILS OF THE DEVONIAN. 145
ties we place S. (ML) fimbriata Conrad, S. (M.) subundifera M. & W., S. (1) compacta Meek, and the Nevada shell under consideration.
S. (M.) undifera and curvatus, var. undulata, Roemer, of the Middle De- yonian of England and the continent of Europe, S. (AZ) erubescens Kichwald (Leth. Ross, p. 703, taf. 34, fig. 18), S. (JZ) undifera, var. Takwanensis,
Kayser, from the Devonian of China, and S. (M.) undifera Ethridge, from Queensland, all appear to belong to the same specific group and show its wide geographic distribution.
It may be more convenient to use the older name S. (M.) fimbriata Conrad for the variety with the strong interrupted stri, as it occurs in the Lower Devonian of New York and the Upper Mississippi Valley region, and Roemer’s name S. (M.) undifera for the smoother, world-wide distrib- uted variety so, well illustrated by Davidson. If so, all the species men= tioned will fall under S. (/.) undifera with the exception of S. (M.) fimbriata.
Professor Hall (Pal. N. Y., vol. iv, p. 216) calls attention to S. (JZ) setigera and S. (M.) pseudolineata as representing in the Carboniferous lime- stone the type of S. (JL) jfimbriata, and Mr. Davidson (Mon. Brit. Dev. Brach., p. 58) states that the resemblances between S. (AL) undifera and the Carboniferous S. (JL) ovalis and S. (AL) pinguis are often so striking as almost to lead one to believe that they are all mere modifications in shape of a single species.
We have called attention in describing S. (1Z.) glaber, var. Nevadensis, to Prof. H.S. Williams’ life history of S. (IZ.) levis =glaber, where he traces its descent from certain Upper Silurian forms through S. (ML.) fimbriata, S. (MT) levis, S. (ML) pramatura, and considers S. (M.) pseudolineata as carrying on
_ the type into the Carboniferous. This arrangement we have accepted, but the presence of the type of S. (JL) pseudolineata in the Lower Devonian suggests the view that the two types S. (M/.) undifera and S. glaber were already differentiated in early Devonian times, and that the line of descent of S. (ML) glaber and S (M.) pinguis and the group of species that each represent were determined in the Upper Silurian age. As we have no rep- resentations of the latter fauna in the West, further comparisons are omit- ted, the reader being referred to Professor Williams’ excellent paper for his views of the Silurian representations of the type of Spirifera under consid- eration (Ann. New York Acad. Sci., vol. ii, 1881).
10c DW
146 PALEONTOLOGY OF THE EUREKA DISTRICT.
Spirifera (M.) setigera occurs in the Lower Carboniferous of the Hureka District, and thus gives a direct local continuation in the Carboniferous of the smooth shell, fig. 3, plate iii, from the base of the Devonian.
Formation and localities —Spirifera (M.) undifera occurs in the Lower Devonian of Atrypa Peak in the Eureka District, and also at the same horizon on Lone Mountain, 18 miles northwest of Eureka, Nevada.
Genus CYRTINA Davidson.
Cyrtina Davidsoniy, n. sp. Plate iii, figs. 2, 2 a-e.
Shell small; general shape more or less triangular or subpyramidal; hinge line a little shorter than the greatest length of the shell.
Ventral valve pyramidal and very much deeper than the dorsal, most prominent at the beak, which varies in elevation and is straight or a little arched over the area; area large, triangular, flat or slightly arcuate, more or less angular on the lateral margins; bent back at varying angles to the general surface of the dorsal valve; fissure long, narrow, and apparently arched, nearly if not quite, over by the pseudo-deltidium; the median sinus is obsolete or else merely a depression between two low, rounded plications.
Dorsal valve semicircular or depressed convex; beak minute and rising a very little above the cardinal line; area linear, very narrow; medium fold obsolete or else a low, rounded plication similar to those on either side.
Surface marked by one or two rounded plications on each side of the medium sinus and fold, or these may be almost entirely absent, showing as slight undulations on the front margins of the valves. Shell structure punctate.
Dimensions: width of valves of largest example obtained, 8""; height of dorsal valve, 6™; depth of ventral valve, 5™™.
This very pretty species of Cyrtina is unlike any known to me. The range of variation in the surface plications is considerable, but I do not think it would pass into such forms as C. heteroclita, a variety with few pli- cations, or C. Hamiltonensis.
FUCSSILS OF THE DEVONIAN. 147
Formation and localities —Middle and Upper Devonian limestone, Tele- graph Peak, and eastern base of Mount Argyle, White Pine Mining District, Nevada.
Cyrtina Hamiltonensis Hall. Cyrtia hamiltonensis Hall, 1857. Tenth Ann. Rep. N. Y. State Cab. Nat. Hist, p. 166. Hamiltonensis Billings, 1861. Canadian Journal, n. ser., vol. vi, p. 262, figs. 80-82. Geol. Canada, 1863, p. 384, figs. 415 a-e. Cyrtina hamiltonensis Hall, 1867. Pal. N. Y., vol. iv, p. 268, pl. xxvii, figs. 1-4; pl. xliv, figs. 26-33, 38-52. Hamiltonensis Meek, 1869. Trans. Chicago Acad. Sci., vol. i, p. 99, pl. xiv, figs. 5, 7, and 10. Hamiltonensis Nicholson, 1874. Rep. Pal. Prov. Ontario, p. 83. Compare Cyrtina heteroclita of authors.
The only specimen of this species recognized in the Eureka District collection is from the Upper Devonian horizon; it is a silicified shell pre- serving the two valves united, and below the average size of full grown individuals from the Hamilton Group of New York and Canada; there appears to be little question of its specific identity with them.
In the collection of Devonian fossils from the Mackenzie River, Brit- ish America, Mr. F. B. Meek recognized this species (Trans. Chicago Acad. Sei., vol. i, p. 100), and he also states that it occurs on Porcupine River, a tributary of the Yukon, longitude 140° W., latitude 67° N.
Formation and locality—Upper Devonian, at The Gate, northwest of Eureka, Nevada.
Genus NUCLEOSPIRA Hall.
Nucleospira concinna Hall.
Atrypa concinna Hall, 1843. Geol. Rep. Fourth District New York, p. 200, fig. 3. Nucleospira concinna Hall, 1859. Twelfth Ann. Rep. N. Y. State Cab. Nat. Hist., pp. 25 and 26. Ibid., Hall, 1867. Pal. N. Y., vol. iv, p. 279, pl. xlv, figs. 33 to 57.
This species is a rare form in Nevada, having been found but sparingly at one locality. At the East it has a wide geographic range in the State of New York, and is also found in the States of Virginia, Maryland, and Indiana. It ranges vertically from the Schoharie grit up into the Hamilton Group.
Formation and locality—Lower horizon of the Devonian limestone, Lone Mountain, northwest of the Eureka District, Nevada.
148 PALEONTOLOGY OF THE EUREKA DISTRICT.
Genus ATHYRIS McCoy. Athyris Angelica Hall.
Athyris angelica Hall, 1861. Fourteenth Ann. Rep. N. Y. State Cab. Nat. Hist., p. 99. Hall, 1867. Pal. N. Y., vol. iv, p. 292, pl. xlvii, figs. 9-20.
This species, in New York, is known only in the Chemung Group, a horizon comparable with the upper beds of the Devonian of the Eureka District, although the fauna is not as specialized as in the East. In all essen- tial particulars the specimens from these widely separated localities are specifically identical, with the exception of one feature, which has not been observed in the New York examples. When the outer part of the shell, with the imbricating lamellze or lamelliform striz is exfoliated, the entire surface is more or less marked by radiating strize. The form of the shell varies, as in the New York specimens, from transverse to elongate, the latter usually prevailing.
Formation and localities —Devonian limestone, The Gate, northwest of Eureka, and Newark Mountain, Eureka District, Nevada.
Athyris (sp. undt.).
A single specimen of this fornt with the shell exfoliated, except on the upper portion, occurs at Lone Mountain, low in the Devonian. It resem- bles Athyris cora, of the Hamilton and Chemung Groups of New York (Pal. N. Y., vol. iv, 291, pl. xlvii, figs. 1-7), but is probably a distinct species.
Genus MERISTELLA Hall. Genus WHITFIELDIA Davidson. Meristella (Whitfieldia) nasuta Conrad (Sp.) Plate iii, figs. 8, 8a, 8b.
Atrypa nasuta Conrad, 1842. Jour. Acad. Nat. Sci. Philad., vol. viii, p. 265, figs. 8, 9. Meristella nasuta Hall, 1860. Thirteenth Ann. Rep. N. Y. State Cab. Nat. Hist., p. 93. elissa Hall, 1861. Fourteenth Ann. Rep. N. Y. State Cab, Nat. Hist., p. 100. Tbid., 1862. Fifteenth Ann. Rep., pl. iii, figs. 21, 22. nasuta Hall, 1862. Fifteenth Ann. Rep. N. Y. State Cab. Nat. Hist., p. 160, figs. 17-19 of p. 161.
FOSSILS OF THE DEVONIAN. 149
Athyris Clara Billings, 1860. Canadian Journal, vol. v, p. 274, figs. 29-32. Ibid., 1863. Geology of Canada, p. 373, figs. 397 a, b.
Meristella nasuta Hall, 1867. Pal. N. Y., vol. iv, p. 299, pl. xlviii, figs. 1-25.
Athyris nasuta Nicholson, 1874. Pal. Proy. Ontario, p. 86.
Compare Whitfieldia tumida Dalman’s (Sp.).
Professor Hall (Pal. N. Y., vol. iv,.p. 299) cites Atrypa nasuta Conrad Ann. Report on the Paleontology of New York, p. 18. I have not been able to find any such reference, but find the original description in the Journal of the Philadelphia Academy of Natural Sciences, as cited above.
A number of examples of this species occur at the Lower Devonian horizon of Lone Mountain, in association with other well-known Upper Helderberg or Corniferous limestone fossils of the eastern side of the conti- nent. None of them attain the large size of many specimens from New York and Canada, but their specific identity with specimens of a corre- sponding size scarcely permits of question. The presence of a narrow depressed line or median sinus on both valves is a character absent on M. nasuta, but present in the closely allied Whitfieldia tumida Dalman (sp.) (Davidson, 1882, Mon. Brit. Foss. Brach., vol. v, p. 107) of the Upper Silurian. The broader depressed fold of the dorsal valve and rounded sinus of the ventral valve are also more characteristic of the latter species.
I am very much inclined to identify this Nevada shell with Whitfieldia tumida, as M. nasuta is scarcely more than a variety of it that obtains, in its later stages of growth, a greater prolongation of the valves. If either the Nevada or New York shells were found in association with I. twmnida, they would scarcely be distinguished in external characters as more than a variety. For the purpose of more clearly presenting the relations of the Devonian faunas of the Rocky Mountains and the eastern half of North America, and while awaiting more material for study, we have retained species under separate names that are considered as varieties of some well- known species.
Formation and locality. —Lower Devonian of Lone Mountain, 18 miles northwest of Eureka, Nevada.
150 PALEONTOLOGY OF THE EUREKA DISTRICT.
Genus ATRYPA Dalman.
Atrypa reticularis (Linnzus sp.) Dalman. Plate xiv, figs. 6, 6a, b.
Synonyms: See Davidson’s Monographs of the British Silurian and Devonian Brachi- opoda.
This extremely variable species is represented by three distinct types in the collections from the Eureka District and Lone Mountain.
The first is a large, robust form similar to that occurring in the Upper Helderberg limestone and Hamilton shales of New York, and designated by Mr. Vanuxem as Hipparionyx (Atrypa) consimilaris, and is illustrated as a variety of Atrypa reticularis (Pal. N. Y., vol. iv, p. 319, pl. li, figs. 9-12).
The variations from this, as shown on the following plate (loc. cit.), also oecur at the lower horizon of the Devonian limestone at County and Woodchoppers Peaks, Sentinel Mountain, Eureka District, and Lone Mountain, 18 miles northwest of Eureka, Nevada.
The second variety is more symmetrical and has very fine radiating costee, resembling the variety from the Hamilton and Chemung Groups in the State of Iowa. The radiating costz, however, are finer, approaching in this respect the radiating striz of the Silurian shell Zygcspira Headi Bil- lings (Pal. Ohio, vol. i, p. 127). It is found in the upper part of the De- vonian at Rescue Hill, at the mouth of Packer Basin, and at The Gate, north- west of Eureka.
The third variety also occurs in the higher beds of the formation at The Gate and east of the Sugar Loaf. In form it is similar to the Silurian examples from the Niagara limestone of New York (Pal. N. Y., vol. ii, p. 270, pl lv, figs. 5a-w). An illustration of it is given on plate xiv, figs. 6, 6a, b, of this report.
Formation and locality—Throughout the Devonian limestone of the Eureka District.
Atrypa desquamata Sowerby.
; Plate xiv, figs. 4,4a. . Synonyms: See Davidson’s Monograph of British Fossil Brachiopoda, vol. iii, pt. 6, p. 58, pl. xi, figs. 1-9.
Several examples of a species of Atrypa, with a distinctly defined area and circular foramen on the ventral valve, were found in the lower beds of
FOSSILS OF THE DEVONIAN. 15h
the Devonian limestone associated with Atrypa recticularis. They are readily separated from that species, but not from the young shell of A. des- quamata, as illustrated by Davidson, to which they are specifically related. The largest specimen has a length of 16™", width of 17", and depth of the two valves of 8™. A. desquamata is a much larger and more robust spe- cies when fully developed, but the similarity in the young shells of the two forms is so strong that we cannot but consider them as specifically identical.
Formation and localities —Lower horizon of the Devonian limestone, Atrypa Peak, south spur; and Lone Mountain, 18 miles northwest of Eu-
reka, Nevada.
Genus TREMATOSPIRA Hall. Trematospira infrequens, n. sp. Plate iv, figs. 3, 3a, b.
Shell transversely elliptical, moderately convex; hinge about three- fourths the width of the shell.
Ventral valve not quite as convex as the dorsal; mesial sinus well defined from the beak to the anterior margin and marked by a single small median plication; beak elevated, small, and truncated by a small perfora- tion. The dorsal valve has a low mesial fold outlined by two strong plica- tions.
Surface of the ventral valve marked by two strong and one slight pli- cation each side of the plication on the edge of the mesial sinus; ventral valve by the same number each side of the central plications of the mesial fold. Shell structure punctate.
This is a distinet and well-marked species, approaching Trematospira camura Hall, 1852 (Pal. N. Y., vol. ii, p. 273, pl. lvi, figs. 3a-t), of the Niag- ara Group and 7. gibbosa Hall, 1867 (Pal. N. Y., vol. iv, p. 272, pl. xlv, figs. 7-15) of the Hamilton Group of New York more nearly than any other spe- cies with which we are acquainted.
Formation and locality—Lower Devonian, Lone Mountain, 18 miles northwest of Eureka, Nevada.
152 PALEONTOLOGY OF THE EUREKA DISTRICT.
Genus RHYNCHONELLA Fischer. Rhynchonella Horsfordi Hall. Plate xiv, fig. 3; plate xv, fig. 6.
Rhynchonella horsfordi Hall, 1860. Thirteenth Ann, Rep. N. Y. State Cab. Nat. Hist., p. 87.
(Stenocisma) horsfordi Hall, 1867. Pal. N. Y., vol. iv, p. 339, pl. liv, figs. 24-32,
A comparison of the Nevada forms of this species with those of the same stage of development from New York prevents their specific separa- tion. But few specimens were found, and it is not an abundant shell in New York, although occurring in the Marcellus and Hamilton shales.
Formation and locality—Devonian limestone, Atrypa Peak, Eureka District, Nevada.
Rhynchonella Tethys Billings.
Rhynchonella tethys Billings, 1860. Canadian Journal, vol. v, p. 270, figs. 20-22. (Stenocisma) tethys Hall, 1867. Pal. N. Y., vol. iv, p. 335, pl. liv, figs. 1-8. This species is very closely related to the preceding, and in making a comparison of the two species with the specimens from Nevada, it is difficult to recognize constant specific characters that distinguish them. Both species are represented in the collections by the extreme forms, and until a large number of well-preserved specimens are collected, it may be premature to propose to unite them in one species. Formation and localities—In the Lower Devonian horizon at Comb’s Peak, and at Lone Mountain, 18 miles northwest of Eureka, Nevada.
Rhynchonella? occidens, n. sp. Plate xv, figs. 3, 3a, b. Shell small, suboval to globose; strongly plicated. Ventral valve slightly less convex than the dorsal. Ventral valve somewhat convex above, becoming depressed midway of its length, with a shallow sinus that extends down and curves beneath; sides uniformly convex to the margins. Beak somewhat elevated and curving
FOSSILS OF THE DEVONIAN. 153
over that of the dorsal valve. Dorsal valve about as wide as long, strongly convex, and with a well-defined mesial elevation on the lower half of the valve; sinuate in front to unite with the projections of the mesial fold of the opposite valve.
Surface with from eleven to thirteen simple, angular plications that grad- ually inerease in size from the apex; of these there are four on the median elevation and three on the sinus.
The dimensions of the largest specimen are: Length, 8"; width, 6”; distance through the greatest convexity of the shell, 5.5""; of the smallest specimen: length, 4""; width, 3.75""; convexity, 8™". The latter has the plications and the mesial fold and sinus developed as in the larger shell. Other examples are less convex, and with the fold and sinus scarcely defined.
In its general aspect this species is similar to some forms of the genus Rhynchospira, and with the discovery of more perfect specimens showing the beak and area of the ventral valve, and the interior spires, if they exist, it may possibly be referred to that genus.
Formation and locality—Lower horizon of the Devonian limestone,
Comb’s Peak, Eureka District, Nevada.
Rhynchonella castanea Meek. Plate xv, figs. 1, la, 4, 4a.
Rhynchonella castanea Meek, 1868. Trans. Chicago Acad. Sci., vol. i, p. 93, pl. xiii, figs. 9a-e.
Shell subglobose; ventricose on the dorsal side, and somewhat flattened on the ventral; length and breadth subequal or a little longer than wide.
Ventral valve slightly convex on the umbo, flattened or slightly convex on the sides, and with a more or less well defined sinus that is first seen about the center of the valve. he sinus has from three to six depressed, rounded plications, and varies in form from the subquadrate, linguiform extension, with subparallel sides in the smaller shells, where it is strongly incurved, to the shorter depression outlined by the elevated, acute margins on the lower part that is not curved beneath even in large individuals. Beak abruptly incurved over that of the opposite valve.
154 PALEONTOLOGY OF THE EUREKA DISTRICT.
Dorsal valve gibbous, sloping somewhat abruptly to the margins of the opposite valve; mesial fold prominent in the younger shells, and marked with three or four plications that extend up to the upper third of the valve. In older specimens the fold is scarcely traceable above the middle of the valve, and the plications, six or eight, are usually short and confined to the lower part.
Surface of younger shells with obscure plications on the sides and stronger, depressed, rounded plications on the mesial fold and sinus. Con- centric lines of growth mark the upper part of each valve. The surface of the older shells is smooth with the exception of the plications on the mesial fold and sinus and a few lines of growth.
This is a somewhat variable species in its different stages of growth. The younger shells are subcuboidal and of the type of Rhynchonella venus- tula Hall (Pal. N. Y., vol. iv, p. 346, pl. liv, A, figs. 24-43) of the Tully limestone of New York, while the adults are subglobose, with the ventral valve less convex, and the angle formed by the union of the sides of the two valves more acute, The two extremes of growth might readily be separated as distinct in their specific characters. The species is of the type of Rhynchonella Emmonsi Hall and Whitfield (Geol. Expl. Fortieth Par., vol. x, p. 247, pl. iii, figs. 4-8) from the Devonian limestone of White Pine Mountains, Nevada; but it is specifically distinct from that species, and also R. venustula and R. cuboides Sowerby (sp.) (Davidson, Mon. Brit. Foss. Brach., vol. iii, pt. 6, p. 65, pl. xiii, figs. 17-21) of the same group of species, although more or less resembling them in some of its phases of develop- ment.
The above was written before I had seen the description and illustra- tion of Mr. Meek’s species, R. castanea, from the Devonian limestone in the Mackenzie River Basin. <A careful comparison of the Nevada specimens with Mr. Meek’s description and figures, leads to the opinion that 2. castanea is one of the variations of the species as it occurs in the Eureka District, and that the latter form should be united with it under the same specific designation, as also the shell illustrated by Mr. Meek as probably a distinct species (Trans. Chicago Acad. Sci., vol. i, plate xiii, fig. 10a, b), but which is the more convex or subeuboidal form of the species.
FOSSILS OF THE DEVONIAN. 155
The locality of the type of R. castanea is given as Lockhart River, British America, latitude, 67° 15’; longitude, 126° W.
Formation and localities Upper Devonian limestone of Rescue Hill and the mouth of Packer Basin, and Lower Devonian on the west slope of County Peak, Eureka District, Nevada.
Rhynchonella duplicata Hall. Plate xiv, fig. 8. Atrypa duplicata Hall, 1843, Rep. Fourth Geol. Dist. N. Y., Organic Remains of the Chemung Group, No. 67, figs. 2, 2 a—b. Rhynchonella (Stenocisma) duplicata Hall, 1867. Pal. N. Y., vol. iv, p. 350, pl. lv, figs. 17-25.
This species has hitherto been known in only a few localities of the Chemung Group in New York. Its author states that it is usually about three-eighths of an inch in length and breadth, rarely attaining the length of half an inch (12.5™). The size is less than that of the Nevada speci- mens, but otherwise the two are in all essential particulars specifically identical. A very perfect shell from the limestone east of the Sugar Loaf has a length of 18™™, with a width of 19", and corresponds in nearly every detail with the type of the species. A large number of perfect specimens were collected at Rescue Hill that present slight differences, which, how- ever, are not considered of specific value. The sharp angular plications and the margins of the sinus on the ventral valve are rounded and de- pressed; the shells are broader than long, having a proportion of 6 to 5, and usually more ventricose, which gives a deeper and more incurved sinus.
Formation and localities—Devonian limestone. Rescue Hill and east of the Sugar Loaf, Eureka District, Nevada.
Rhynchonella pugnus Martin. Plate xiv, figs. 7, 7a.
Conchyliolithus anomites pugnus Martin, 1809, Petrificata Derbiensia, tab. xxii, figs. 4,5. Atrypa pugnus Sowerby. Geol. Trans. 2d Series, vol. v, pl. lvi, figs. 15-18. Terebratula pugnus Phillips, 1841. Paleozoic Fossils of Devon., ete., p. 87, pl. xxxv, figs. 156 a-e. anisodonta Phillips, 1841. Tbid., p. 86, pl. xxxiv, figs. 154 a-e.
156 PALEONTOLOGY OF THE EUREKA DISTRICT.
Rhynchonella pugnus Davidson, 1861. Mon. Brit. Carb. Brach., p. 97, pl. xxii, figs. 1— 15. Ihbid., Mon. Brit. Devonian Brach., 1865, p. 63, pl. xii, figs. 12-14; pl. xiii, figs. 8-10. :
Missouriensis Meek, 1866. Geol. Survey Illinois, vol. ii, p. 153, pl. xiv, figs. 4a, b. Fig. 5a of pl. C., 2d Ann. Rep. Geol. Sury. Missouri, 1855, is also referable to Rhynchonella pugnus, as stated by Mr. Meek. Not R. Missouriensis Meek, 1868. Ibid, vol. iii, p. 450, pl. 14, fig. 7 a-d.
alta Calvin, 1877. Paper read before the Iowa Academy of Sciences and a named photographed plate distributed. pugnus Williams, 1883. Amer. Jour. Sci., vol. xxv, p. 99.
The varietal differences among the Nevada specimens from the same layer or rock are quite marked, in this respect resembling the New York forms described by Prof. H. 8. Williams (Amer. Jour. Sci., vol. xxv, p. 97, 1883) and the English type illustrated by Mr. Davidson more than the Iowa form of Mr. Calvin, although medium-sized specimens appear to be per- fectly identical with the latter.
The plications on the valves vary from eight to ten on some examples and four to six on others. In the young and medium-sized shells the plica- tions do not extend more than one-half the way up from the anterior margin, while in the larger examples they reach nearly to the extremity of the beak.
Under the name of Rhynchonella Missouriensis Shumard, -Mr. Meek, Joc. cit., describes and illustrates a shell which he considered as closely allied to varieties of Rhynchonella reniformis and R. pugnus, from the Carboniferous limestone of England and Ireland. This type was what Dr. Shumard con- sidered as the young of R. Missouriensis, describing and illustrating at the same time a larger shell generically distinct from it, if we consider his fig- ure, 5a(2d Ann. Rep. Geol. Surv. Missouri, plate C), as a form of A. pugnus, as suggested by Mr. Meek. Later, in vol. iii of the Illinois Survey, Mr. Meek describes and illustrates the larger shell described by Dr. Shumard, and again speaks of the relations between the smaller shell figured by Dr. Shumard and R. pugnus, retaining the name I. Missouriensis for the former if the latter proved to be identical with R. pugnus.
In the collections of the American Museum of Natural History, Prof. R. P. Whitfield showed me casts of Shumard’s R. Missouriensis that prove it to belong to the genus Camarophoria as determined by him.
FOSSILS OF THE DEVONIAN. 157
Formation and locality—Devonian limestone; associated with R. dupli- cata and R. (L.) Laura. The Gate, northwest of Eureka, Eureka District, Nevada.
Rhynchonella Emmonsi H. & W.
Rhynchonella Emmonsi Hall & Whitfield, 1877. Geol. Expl. Fortieth Par., vol. iv, p.247, pl. iii, figs. 4-8.
intermedia Barris, 1878. Proc. Davenport Acad. Nat. Sei., vol. ii, p. 285, pl. xi, figs. 5-6.
With the type of Rhynchonella Emmonsi before me, and a typical speci- men of Rhynchonella intermedia, received from Rey. W. H. Barris, to compare with it, I fail to observe any specific differences between them. The slight differences mentioned by the author of FR. intermedia would not serve to separate the two shells, if found in the same stratum of rock, and the range of variation in most species of the genus Rhynchonella is far greater than between the two shells under consideration. R. Emmonsi is a rare form in the Upper Devonian of the White Pine District, Nevada, and Rev. Mr. Barris writes me that it is also rarely met with in the Upper Devonian of Towa.
There is little doubt but that Rhynchonella intermedia, R. Emmonsi, and R. venustula Hall are varieties of R. cuboides of the Devonian of Europe, and when the opportunity offers to illustrate a series of specimens I think this can readily be shown. _
Many American species now under local names will ultimately be placed with species described from Europe, and the reverse will also be true when American species have priority. Our knowledge of the widespread geographic distribution of paleozoic species will be greatly increased with better facilities for the comparison of specific forms from the great conti- nental areas and islands.
Subgenus LEIORHYNCHUS Hall. Rhynchonella (Leiorhynchus) Nevadensis, n. sp. Plate xiv, figs. 9, 9a, b. Shell ovate or suborbicular, usually broader than long, or length and
breadth subequal; increases in rotundity with growth. Ventral valve in adult individuals gibbous above, curving uniformly
Lise. PALEONTOLOGY OF THE EUREKA DISTRICT.
to the sides or becoming slightly depressed, flattened below the center, and more or less sinuate on the lower part. Beak acute and closely incurved over that of the opposite valve. Dorsal valve uniformly convex, the con- vexity increasing with the size of the individual; a broad, hardly percep- tible mesial fold is seen on the lower part of the valve only in the larger shells.
Surface marked by a few obscure plications on the mesial fold and in the sinus that become obsolete midway to the apex. On the surface of well-preserved specimens concentric striae occur which at intervals are crowded together, forming slight ridges.
There is considerable variation between young and adult specimens. Those 15™" in length show but a trace of the mesial fold and sinus or of the surface plications; the ventral valve is more uniformly convex, less de- pressed below, and subequal to that of the dorsal valve. In this condition it bears a close resemblance to the young shells of some of the larger forms of the genus Meristella.
This species is closely related to R (L.) Kelloggi Hall (Pal. N. Y., vol. iv, p. 361, pl. lvii, figs. 1-12) of the Chemung Group of New York, the char- acter of the mesial fold and sinus and the surface plications serving to dis- tinguish it from that species.
Formation and locality —Devonian limestone. Rescue Hill, near Rescue Canon, Eureka District, Nevada.
Rhynchonella (Leiorhynchus) sinuatus Hall. Plate xiv, fig. 5. Leiorhynchus sinuatus Hall, 1867. Pal. N. Y., vol. iv, p. 362, pl. lvii, figs. 13-17.
The specimens of this species from the Chemung Group of New York are all more or less compressed, and none show the true convexity of the shell and surface plications With this in view, the perfect and uncom- pressed specimens from the limestone of the Eureka District are specifically identical with them. There is considerable variation among the specimens from the same bed; some are more elongate than the New York forms, while others are almost a counterpart of them.
FOSSILS OF THE DEVONIAN. 159
Formation and localities—Upper horizon of the Devonian limestone; The Gate, northwest of Eureka, Rescue Hill, and near the mouth of Packer Basin, Eureka District, Nevada.
Rhynchonella (Leiorhynchus) Laura Billings.
Rhynchonella ? Laura Billings, May, 1860. Canadian Journal, vol. V, p. 273, figs. 26-28. Leiorhynchus multicosta Hall, December, 1860. Thirteenth Ann. Rep. N. Y. State Cab. Nat. Hist., p. 85. Rhynchonella? Laura Billings, 1863. Geol. of Canada, p. 384, figs. 418 a—c. Leiorhynchus multicosta Hall, 1867, Pal. N. Y., vol. iv, p. 358, pl. lvi, figs. 26-40. The Nevada examples of this species are usually broader, more convex, and. with stronger plications than those from the argillaceous shales of the Hamilton Group of New York. These features, however, are quite as prominent in the specimens from the arenaceous beds at Richmondville, Schoharie County, New York, and the calcareous shales at Bosanquet and Widder, Canada West. The latter localities afford specimens showing the phases of development observed in the New York and Nevada examples, and show the specific connection of the eastern and western forms. Formation and locality—Upper horizon of the Devonian limestone; associated with Rhynchonella pugnus, at The Gate, northwest of Eureka, Nevada.
Genus PENTAMERUS Sowerby. Subgenus GYPIDULA Hall. Pentamerus comis Owen. Plate iii, figs. 4 and 7; pl. xiv, figs. 15, 15 a, b; pl. xv, figs. 5, 5 a, b.
Atrypa comis Owen, 1852. Rep. Geol. Surv. Wis., Iowa, and Minn., p. 583, pl. iii A, fig. 4.
Pentamerus occidentalis Hall, 1858. Geol. Iowa, vol. i, pt. 2, p. 514, pl. vi, figs. 2 a-c. Not Pentamerus occidentalis Hall, 1852, Pal. N. Y., vol. ii, p. 341, pl. Ixxix, figs. la-s, 2. ;
Pentamerus galeatiform Meek & Worthen, 1866. Geol. Surv. Illinois, vol. ii, p. 325, (foot note.)
Gypidula occidentalis Hall, 1867. Pal. N. Y., vol. iv, p. 380, pl. lviii a, figs. 1-8.
Pentamerus comis Meek & Worthen, 1868. Geol. Surv. Illinois, vol. iii, p. 428, pl. xiii, figs. 6 a-c.
160 PALEONTOLOGY OF THE EUREKA DISTRICT.
Shell ovoid or subglobose; very inequivalve; hinge line varying from two-thirds to three-fourths of the entire width of the shell.
Ventral valve arcuate, much deeper than the dorsal, gibbous or regu- larly ventricose above the middle; beak strongly incurved over that of the opposite valve; fissure of medium size, and bordered by a more or less dis- tinct area, the surface of which is smooth or transversely striated. The spoon-shaped pit in the interior of the valve is moderately extended; median septum yery short. Central portion of the valve with a slightly elevated, broad, more or less distinctly defined mesial fold.
Dorsal valve full above, becoming depressed below the middle and flattened at the sides; the front is flattened and slightly extended, forming a broad, more or less distinct sinus. Lamelle separate and diverging.
Surface obscurely plicated on the lower central portion of the larger shells, and one shows traces of very fine radiating strize on the lower part of the ventral valve.
The specimen described is smaller than the average, having a height and width of 35™", with the diameter of the convexity of the valves of 30™"; a large ventral valve is 50" in length.
Formation and localities —Devonian limestone, lower horizon; Comb’s Peak, Eureka District, and Lone Mountain, 18 miles northwest of Eureka, Nevada.
The most striking differences between the Nevada shell and that of Iowa is the great size and the almost entire absence of plications on the former. We cannot, however, avoid the conclusion that they belong to the same species, the Nevada form attaining a greater size and in many instances a broader form. In other examples the specific identity is without question.
When preparing specimens for the draughtsman it was thought that figs. 15, 15, b, plate xiv, represented one species, figs. 5, 5 a, b another, and Pen- tamerus occidentalis Hall, loc. cit., still another.
By the collection of a large series of specimens from the original locality in Nevada, and the bringing together of a fine suit of specimens representing the Devonian P. occidentalis Hall (the latter through the kind- ness of Prof. Samuel Calvin and Rey. William H. Barris, of Iowa), I
FOSSILS OF THE DEVONIAN. 161
found that the three varieties were united by a series of specimens having intermediate characters between the extremes I had designated as distinct species. On examining the interiors of the valves of the lowa and Nevada shells, they were found to be similar; also the area, which is of a variable character. In a beautiful series of specimens from Independence, Lowa, received from Professor Calvin, the area of the ventral valve varies greatly in extent and height, and many of them showed no more of a decided area than specimens of P. galeatus, now before me, from the Lower Helderberg Group of Albany County, New York. On one of Professor Calvin’s speci- mens from Solon, Iowa, the area appears to be vertically striated, but a close examination shows this to have originated from the scratching of the tool . used in cleaning away the matrix. All other specimens from Iowa and Ne- vada showing the area intact, are transversely striated. When the area is not well defined the strize of growth arch around the rounded lateral margins and reach in to the edges of the vertical fissure. Professor Hall describes the area as vertically striated; we have failed to find. any specimens showing the vertical striz. The presence of fine radiating strie is not mentioned either by Owen, Hall, or Meek and Worthen, but they are present on speci- mens from Davenport, Troy Mills, and Independence, Iowa, and the Eureka District, Nevada. Concentric striz are also well defined on many speci- mens, while others show little more than a smooth surface.
I think the identification of this species by Meek and Worthen with that of Owen is correct, and it also establishes a specific name, as the genus Gyp- idula Hall, does not appear to have good generic characters to distinguish it from typical forms of Pentamerus, and if the species is referred back to the latter genus, the name occidentalis cannot be used owing to its being pre- occupied.
Pentamerus Lotis, n. sp.
Plate iii, figs. 9, 9a-c.
Shell small, subglobose, transverse or with the height and width sub- equal. Dorsal valve deeper and more convex than the ventral; regularly
arched from beak to front, with a strongly marked somewhat flattened me- llcDw
162 PALEONTOLOGY OF THE EUREKA DISTRICT.
sial fold having a shallow median sinus; beak short, incurved. Ventral - valve most convex towards the beak, flattening out in the broad mesial sinus; the latter is marked by a low rounded median plication.
Surface of dorsal valve marked by a single low plication on each side of the mesial fold that corresponds’to a shallow sinus each side of the pli- cation bordering the large mesial sinus of the ventral valve; a few fine con- centric lines of growth are visible by the aid of a strong lens.
Dimensions: height of largest specimen in the collection, 9™"; width, 12™™; convexity of the two valves united, 8™™.
On a shell having a height of 4°", a transverse diameter of 5", and a depth of 2.25™™ for the two valves, the mesial sinus and fold are shown only by an undulation in the front margin, the valves are subequal in convexity and the beak of the dorsal valve is scarcely elevated above that of the ven- tral. With the increase in the size of the shell, the features of the adult. gradually appear until, in the largest specimens, there is very little variation in form except a greater or less convexity as the shell is more or less trans- verse.
Of American species Pentamerus subglobosus M. & H. (Geol. Illinois, vol. iii, p. 429, plate xiii, figs. 5 a—c), approaches this species in size and form, but the numerous plications and different convexity of the valves distinguish them. Pentamerus biplicatus Schnur, of the Middle Devonian of England (Davidson, Mon. Brit. Foss. Brach., vol. iii; p. 73), may also be compared with P. Lotis.
It is with considerable hesitancy that this Upper Devonian shell is referred to a new species, as it may possibly be a form descended from P. comis, of the Lower Devonian of the Eureka District. No young shells of the latter species have been found that we can compare with the earlier stages of growth of P. Lotis, but in the larger form of the two species de- cided differences appear, as may be seen by a comparison of the figures representing them.
Comparing P. Lotis with smooth specimens of P. comis, from the Upper Devonian horizon at Rockford, Iowa, we find a decided resemblance between them, but not sufficient to unite them as one species.
Formation and locality—Upper Devonian, on the west side of Apple- gate Cation, White Pine Mining District, Nevada.
FOSSILS OF THE DEVONIAN. 163
Genus CRYPTONELLA Hall. Cryptonella? circula, n. sp. Plate xv, figs. 2, 2a, b.
Shell small, subcircular or ovoid. The depth of the two valves, in uncompressed specimens, is equal to one-half the length of the shell.
Ventral valve moderately convex, most prominent about one-third the distance from the apex to the front, from which point it slopes regularly to the margins and beak; a slight depression of the front margin is the only indication of a mesial sinus; beak scarcely incurved, truncated by a small round foramen, that, in the absence of the deltidial plates, opens below into a rather large deltoid fissure that has a narrow, flattened, area-like space on each side. Dorsal valve somewhat shorter than the ventral and subequal in convexity with it. Beak very small and not perceptibly incurved.
Surface marked by fine concentric striz. Shell structure punctate.
Dimensions: the largest shell, in a collection of thirty specimens, has a length of 9™", breadth of 8.5™™, and depth of the two valves of 4.5™™.
The species is referred to the genus Cryptonella, from its general form, the character of the beak of the ventral valve and the punctate shell struc- ture, the latter character shown on one of the silicified specimens. With these characters the reference is provisional, as the internal features are yet undetermined.
Formation and locality—Devonian limestone; Lone Mountain, 18 miles northwest of Eureka, Nevada.
Cryptonella Pinonensis, n. sp. Plate iv, figs. 4, 4a, b.
Shell subovate; widest about the middle; valves about equally convex; rounded to slightly transverse in front.
Ventral valve regularly arcuate, most convex midway; beak elevated, slightly incurved, and truncated by a small rounded foramen bounded on the lower side by two rather prominent deltidial pieces; the slopes from the beak are abruptly deflected on the sides down to the cardinal margin.
164 PALEONTOLOGY OF THE EUREKA DISTRICT.
Dorsal valve not quite as convex as the ventral; most elevated at the center, from which point it curves regularly to the margins; beak incurved beneath the deltidial plates of the ventral valve.
Outer surface exfoliated. Shell structure punctate.
The generic reference is based entirely on external form and character; nothing is known of the interior characters, except two elongate, median, muscular imprints on the ventral valve. The specific relations appear to be nearest some forms of Cryptonella planirostra of the Hamilton Group of New York. A direct comparison with the types of that species, and also of C. rectirostra Hall, leads us to think that the Nevada form is distinct from each,
Formation and locality—Upper Devonian; south end of the Pinon Range at The Gate, northwest of Eureka, Nevada.
LAMELLIBRANCHIATA.
Our knowledge of this class of shells in the Devonian Group of the area embraced within the Rocky Mountains has been up to the present time very limited, Mr. Meek having described but three species, viz, Hdmondia ? Pinonensis, Aviculopecten catactus, and Lunulicardium fragosum, the types of which were collected by the geologists of the Fortieth Parallel Geological Survey,in Central Nevada. To this list we have added twenty-three genera, represented by thirty-five species. Of these, eight species are identical with species in the Eastern Paleozoic area of Ohio and New York, viz:
Actinopteria Boydi. Paracyclas occidentalis. Pterinea flabella. Leiopteria Rafinesqui. Sanguinolites rigidus. Sanguinolites? Sanduskyensis. Sanguinolites ventricosus. All of the twenty-three genera, with the exception of Posidonomya, are identical with Devonian genera of the Eastern United States. In the systematic catalogue at the end of this volume the vertical range of the various species in the Devonian Group of the Eureka District is
given.
FOSSILS OF THE DEVONIAN. 165
From the results obtained by a few days’ collecting at the Lower Devonian horizon, there is little doubt but that by a more extended search the number of species could be greatly increased over the twenty-seven now known from that horizon.
One species, Paracyclas occidentalis, passes from the lower to the upper horizon, and unites with the eight species occurring there to make a total of nine species occurring in a horizon stratigraphically equivalent to that of the Chemung Group of New York.
Genus PTERINEA Goldfass.
Pterinea flabella Conrad (Sp.). Plate xv, fig. 12; pl. v, fig. 6.
Avicula flabella Conrad, 1842. Jour. Acad. Nat. Sci. Philad., vol. Viii, p. 238, pl. 12, fig. 8. Pterinea flabellum Hall & Whitfield, 1872. Twenty-fourth Ann. Rep. N. Y. State Museum Nat. Hist., p. 199.
Hall, 1883. Pal. N. Y., vol. v, pt. 1, Plates and Explanations, p. 7;
pl. xiv, figs. 1-21; pl. xv, figs. 1, 4,5, 8-10. Ibid., 1884, Text, p. 93.
This species, which in Ohio and New York ranges from the Upper
Helderberg to the Chemung Groups, is found only at the Lower Devonian horizon of Lone Mountain, 18 miles northwest of Eureka, Nevada.
The specimen illustrated shows the characteristic form, and is similar
to that from the typical localities in the Hamilton Group of New York.
Pterinea Newarkensis, n. sp. Plate v, fig. 12.
General form broadly truncate, suboval; length and breadth subequal; cardinal margin straight, nearly if not quite equaling the greatest width of the valves.
The right valve is depressed, slightly convex at the umbonal region; beak depressed; anterior surface of posterior wing marked by a few linear, radiating lines, the body of the shell showing only a few concentric lines of growth. The posterior muscular scar is oval in form and quite shallow.
166 PALEONTOLOGY OF THE EUREKA DISTRICT.
Left valve unknown.
Dimensions : length of shell, 4.5°™; width the same.
This species is closely related to Pterinea Chemungensis Conrad (Pal. N. Y., vol. vy, pt. 1, p. 98, 1884) from the Devonian of New York. It differs in the more anterior position of the beak and less elongate outline.
Formation and locality—Upper Devonian of Newark Mountain, Eureka District, Nevada.
Genus ACTINOPTERIA Hall.
Actinopteria Boydi Conrad (Sp.). Plate v, fig. 2. Avicula Boydii Conrad, 1842. Jour. Acad. Nat. Sci. Philad., vol. viii, p. 237, pl. xii, fig. 4. Pterinea Boydi Miller, 1877. Cat. Amer. Pal. Fossils, 2d ed., p. 201. Actinoptera Boydi Hall, 1883. Pal. N. Y., vol. v, pt. 1, Plates and Explanations, p. 8; pl. xix, figs. 2-24. Actinopteria Boydi Hall, 1884. Pal. N. Y., vol. v, pt. 1, p. 113.
There is only a single left valve of this species in the collection, and that is somewhat distorted by pressure. A direct comparison with authentic specimens from the Hamilton Group of New York shows such a striking similarity between them and the Nevada shell that there is little hesitancy in identifying the species by the one specimen.
Formation and locality—lLower Devonian of Lone Mountain, 18 miles northwest of Eureka, Nevada.
Genus LEIOPTERIA Hall. Leiopteria Rafinesquii Hall. Plate v, figs. 10, 10a. Leiopteria Rafinesquii Hall, 1883. Pal. N. Y., vol. v, pt. 1, Plates and Explanations, pp. 7,9; pl. xv, fig. 11; pl. xx, figs. 6,7. Ibid., 1884, text, p. 161.
The examples of this species from Nevada embrace both the Upper Helderberg and Hamilton Group forms, as illustrated in the Paleontology of New York. The identification is made with the figures, as we have no typical specimens of the species for comparison.
Formation and locality—Lower Devonian of Brush Peak and Atrypa Peak, Eureka District, Nevada.
FOSSILS OF THE DEVONIAN. 167
Genus LEPTODESMA Hall.
Leptodesma transversa, 0. sp.
Plate v, fig. 13.
tal
General form transversely ovate or oblong. General surface of the left valve strongly convex, but not gibbose. Hinge straight and continued posteriorly to the acute termination of the wing, which appears to have had a short spinose extension. Beaks small, arching over the cardinal line.
Surface marked by numerous concentric lines of growth.
Interior characters unknown.
Dimensions: height, 7°"; breadth, 12"; convexity of left valve, 2.5".
With the exception of Leptodesma naviforme Hall (Pal. N. Y., vol. v, pt. 1, p. 200), of the Chemung Group of New York, this species is more oblique and transverse than any species known to me.
Formation and locality.—Upper Devonian, Chemung horizon, at The Gate, northwest of Eureka, Nevada.
Genus LIMOPTERA Hall.
Limoptera sarmenticia, 0. sp.
Plate v, figs. 3, 3a, b.
Shell oblique, subovate in outline within the extension of the posterior wing. Left valve strongly convex. Hinge-line straight ; ligamental area unknown. Beak of left valve elevated and incurved over the cardinal line.
Surface marked by concentric lines of growth, and not very strong radiating strie.
Interior characters unknown.
Dimensions: height of a narrow specimen, 3.25%; breadth, 2.5°™; con- vexity of left valve, 1.25; of a broad specimen: height, 3°"; breadth, 3; convexity of left valve, 1.25%.
This is unlike any species of the genus known to me. The variation in form among the different specimens is considerable, as is shown by figs. 3aand 3b. The surface strie are usually absent in the cast.
168 PALEONTOLOGY OF THE EUREKA DISTRICT.
The specific name is given from the character of the localities at which it occurs; both Brush and Atrypa Peaks are covered with brushwood.
Another strongly marked species of Limoptera occurs in the Lower Devonian. It is much larger and more erect than the species under con- sideration. Unfortunately, the material does not permit of specific deter- mination.
Formation and locality—lLower Devonian of Brush and Atrypa Peaks, Eureka District, Nevada.
Genus MYTILARCA Hall.
- Mytilarca dubia, n. sp.
Plate iv, fig. 5.
General outline broadly ovate. Hinge-line short, projecting a short distance beyond the contour of the body of the shell.
Left valve unknown. The beak of the right valve is somewhat acute and projects over and above the hinge line; area unknown. General sur- face strongly convex. Surface of valve apparently smooth.
Dimensions: length, 4.25°"; greatest breadth, 3.75™.
In the absence of the ligamental area and the interior of the valves, this species is provisionally referred to the genus Mytilarca. In general form it is related to Mytilarca (Plethomytilus) oviformis (p. 169) of the Hamil- ton Group of New York.
Formation and locality—Lower Devonian, Lone Mountain, 18 miles northwest of Eureka, Nevada.
Mytilarca Chemungensis Conrad. Plate iv, fig. 9.
Inoceramus Chemungensis Conrad, 1842. Jour. Acad. Nat. Sci., Philad., vol. viii, p. _ 246, pl. xiii, fig. 9. Mytilus Chemungensis Phillips & Salter, 1848. Memoirs Geol. Surv. of Great Britain, vol. ii, pt. 1, p. 365, pl. xx, figs. 10,11. (This is probably a distinct species.) Mytilarca Chemungensis Hall, 1870. Prelim. Notice Lam. Shells, p. 23. Ibid., 1883. Pal. N. Y., vol. v, pt. 1; Plates and Explanations, p. 11; pl. xxxii, figs. 8-14. Ibid., 1884. Text, p. 258.
FOSSILS OF THE DEVONIAN, 169
As far as can be determined by a comparison of the single right valve that we have of this species with specimens, and also Professor Hall’s figures, it is identical with the New York species. It occurs in association with the following Chemung species: Orthis.impressa, Productus speciosus, P. lachry- mosa, vars. lima and stigmata, Spirifera disjuncta, Athyris Angelica, Rhyncho- nella sinuata, Sanguinolites rigidus.
Formation and locality—Upper Devonian, at The Gate, northwest of Eureka, Nevada.
Subgenus PLETHOMYTILUS Hall.
Mytilarca (Plethomytilus) oviformis Conrad. Plate vy, fig. 11.
Inoceramus oviformis Conrad, 1842. Jour. Acad. Nat. Sci., Philad., vol. viii, p. 246, pl. xiii, fig. 7. :
Mytilarca oviformis Hall, 1870, Prelim. Notice Lam. Shells, p, 21.
Plethomytilus oviformis Hall, 1883. Pal. N. Y., vol. v, pt. 1; Plates and Explanations, p. 11; pl. xxxi, figs. 1-8.
Mytilarca (Plethomytilus) oviformis Hall, 1884. Pal. N. Y., vol. v, pt. 1, p. 255; pl. Ixxxvii, fig. 8.
But a single left valve of this species has been obtained. In form and external characters it corresponds too closely with M. (P.) oviformis of the Hamilton Group of New York to admit of a specific separation. It may be that if the ligamental area and hinge were known, differences of generic value would appear, but with the present knowledge of the shell this is not anticipated.
Formation and locality—lLower Devonian, Lone Mountain, 18 miles northwest of Eureka, Nevada.
Genus MODIOMORPHA Hall. Modiomorpha altiforme, n. sp.
Plate v, fig. 9.
Shell transverse, suboval to subquadrangular in outline. General sur-_ face strongly convex, with the umbonal ridge prominent.
170 PALEONTOLOGY OF THE EUREKA DISTRICT.
Valves with small incurved beaks situated well towards the anterior end of the nearly straight cardinal line.
Surface, as shown by the impression left in the cast, marked by con- centric lines of growth.
Dimensions: height, 4°"; breadth, 6.5°"; convexity of right valve, 17".
Four specimens of this species have been obtained, all in the form of casts. The transverse subquadrangular form serves to distinguish it from Modiomorpha alta of the Hamilton Group of New York, which is the most nearly allied species. Some specimens that are referred to M. alta are almost identical in form, but the typical forms differ materially, as may be -seen by comparing our figure with those given of the New York species (Pal. N. Y., vol. v, pt. 1, Plates and Explanations, pl. xxxvii).
Formation and locality—lLower Devonian; Lone Mountain, 18 miles northwest of Eureka, Nevada.
Modiomorpha oblonga, n. sp.
Plate v, fig. 7.
Shell transversely elliptical or elongate-ovate. General surface mod- erately convex, with a distinct, rounded umbonal ridge.
Hinge-line shorter than the length of the shell and nearly straight. Beaks anterior, small, and incurved. Surface marked by concentric lines of growth.
Dimensions: height, 2.75°"; breadth, 5.5°"; convexity of left valve, OSS.
This species is more nearly related to Sanguinolites ? Sanduskyensis Meek (Pal. Ohio, vol 1, p. 209, pl. xviii, fig. 3), from the Helderberg Group of Ohio, than to any other species with which we are acquainted. It is less expanded posteriorly, and the anterior extremity is not as nasute. The generic reference is made on the general form, as the hinge characters are unknown.
Formation and locality—Lower Devonian of Atrypa Peak, Eureka District, Nevada.
FOSSILS OF THE DEVONIAN. 171
Modiomorpha obtusa, n. sp.
Plate iv, figs. 8, 8a.
Shell subrhomboidal in outline. General surface strongly convex, the umbonal ridge rounded. Hinge-line about one-half the length of the shell. Beaks small, incurved, and situated on the anterior third of the cardinal por- tion of the shell.
Surface marked by a few concentric lines of growth. Anterior muscu- lar sear large, well defined; other interior characters unknown.
Dimensions: height, 1.5°™; width, 2.5; depth of right valve, 0.5™.
To some of the more transverse forms of Modiomorpha quadrula Hall (Pal. N. Y., vol. v, pt. 2, Plates and Explanations, pl. xli, figs. 18-26), this species bears a stronger resemblance than to any other form we know. It differs in the character of the umbonal ridge and the posterior extension of the shell. ;
Formation and locality—Lower Devonian of Brush Peak, Eureka Dis- trict, Nevada, and also at the same horizon on Lone Mountain, 18 miles northwest of Eureka, Nevada.
Genus GONIOPHORA Phillips. Goniophora perangulata H. Plate xv, fig. 10.
Sanguinolites perangulatus Hall, 1870. Prelim. Notice Lam. Shells, p. 35. Goniophora perangulata Hall, 1883. Pal. N. Y., vol. v, pt. 1, Plates and Explanations, p. 12, pl. xxxiv, figs. 1-7.
In identifying this species a direct comparison was made between the specimens from Nevada and the type specimens from the Upper Helder- berg Group of New York, at the New York State Museum of Natural His- tory, Albany, N.Y. No variations of specific value were observed; the identification is further strengthened by the presence of Pterinea flabella and several species of Brachiopods, that are associated with the species at each locality
Formation and locality—lLower Devonian; Lone Mountain, 18 miles northwest of Eureka, Nevada.
172 PALEONTOLOGY OF THE EUREKA DISTRICT.
Genus NUCULA Lamarck. Nucula Rescuensis, n. sp. Plate xv, fig. 9.
Shell small, broadly subovate, moderately convex; height to length as four to five; beaks not very prominent, about one-fifth the length from the broadly rounded anterior end; basal line broadly and uniformly curved; posterior end more sharply curved, and with the upper slope meeting the nearly straight hinge-line at an obtuse angle; posterior umbonal slope prominent and subangular.
Surface, in the cast, shows evidence of concentric lines of growth where the cast is very perfect, otherwise it is smooth.
Formation and locality—Middle to Upper Devonian horizon; Rescue Hill, west of Rescue Canon, Eureka District, Nevada.
Nucula, sp.?
Among the collections from Rescue Hill a number of casts of a larger species of Nucula than N. Rescuensis occur. Their form is much like that of N. Niotica of the Upper Helderberg Group of New York, but without some knowledge of the outer shell it is scarcely possible to determine whether it is that species, or a new form allied to some of the Devonian or Chemung species of New York.
Genus DYSTACTELLA Hall. Dystactella insularis, n. sp.
Plate xv, fig. 8.
Shell transversely elongate-ovate, the length and height as two to one; valves moderately convex; anterior end contracted and sharply rounded at the extremity; basal line gently arcuate; posterior end some- what broadly rounded, the extremity coming above a line drawn through the transverse center of the shell; cardinal line a little curved; beaks depressed.
Surface of cast marked by a strong anterior muscular scar; posterior scar not observed.
FOSSILS OF THE DEVONIAN. 7a
In general appearance this shell resembles a Nuculites or Palzeoneilo, but it is without the clavicular ridge of the former and the faint muscular scars of the latter. In the presence of the strong anterior muscular scar, the somewhat nasute anterior end and the rounded up posterior extremity it is allied to Dystactella subnasuta, Hall (Pal. N. Y., vol. y, pt. 1, Plates and Explanations, p. 14, pl. li, figs. 28-31, 1883) from the Upper Helderberg rocks of the Falls of the Ohio.
Formation and locality—lLower part of the Devonian limestone in the lower or central area of Gray’s Canon, Eureka District, Nevada.
Genus MEGAMBONIA Hall.
Megambonia occidualis, n. sp. Plate v, fig. 1.
Outline subcireular. Length and breadth subequal. General sur- face strongly convex, with a convex anterior wing separated from the body of the shell by a well-marked, slightly curved sinus. Hinge-line shorter than the width of the shell.
Right valve unknown. Left valve with the beak depressed and cury- ing forward over the cardinal line. Area and interior characters unknown.
Surface marked by strong concentric striz and lines of growth; a few radiating lines are shown in the posterior half of the shell.
The most nearly related species is Megambonia subcordiformis Hall (Pal. N. Y., vol. v, pt. 1; Plates and Explanations, pl. lii, figs. 1, 8). The dif- ferences are the less elongate form and the character of the surface markings.
Formation and locality—lLower Devonian; Lone Mountain, 18 miles northwest of Eureka, Nevada.
Genus NYASSA Hall.
Nyassa parva, 0. sp. Plate xv, figs. 14, 14a.
Shell small, transversely elongate, with the cardinal and basal margins subparallel, the posterior end being a little broader than the anterior; the
174 PALEONTOLOGY OF THE EUREKA DISTRICT.
width about twice the height; beaks moderately prominent and incurved, situated near the anterior end, which is rather abruptly rounded; basal line slightly sinuate midway; posterior end obliquely rounded, truncate above the lower third, rounding into the basal line and forming a very obtusely rounded angle with the cardinal margin; cardinal line nearly straight and declining towards the anterior end; umbonal ridge prominent, subangular, becoming more rounded toward the extremity of the posterior portion of the shell.
Surface showing a few lines of growth. Anterior muscular scar small, semicircular, and near the anterior margin; posterior scar subcircular, not strongly defined, situated on the postero-cardinal slope, near the margin.
This species resembles Nyassa recta Hall (Pal. N. Y., vol. v, pt. 1, Plates and Explanations, p. 14, pl. liii, figs. 1-8, 1883) of the Hamilton Group of New York, but differs in the outline of the valves and its less prominent beaks.
Formation and localities—Lower Devonian; on the west slope of County Peak, Middle to Upper Devonian, at Rescue Hill, west of Rescue Canon, Newark Mountain, and east side of Packer Basin, Eureka District, Nevada.
Genus GRAMMYSIA De Verneuil. Grammysia minor n. sp. Plate xv, figs. 15, 15a.
Shell very small, transversely elongate-ovate; valves ventricose; beaks strongly incurved, situated near the anterior end, which slopes abruptly from the beak with a slightly concave outline to the somewhat sharply rounded end that passes below into the basal line; this, with the exception of a slight sinuosity caused by the median or byssal groove, is transverse to where it rounds up slightly on the posterior margin to meet the oblique line of the upper postero-margin, with which it forms an obtuse angle, giving the posterior end of the shell’a pointed appearance; cardinal line straight about two-thirds the length of the valve; umbonal ridge rounded or subangular, postero-cardinal slope abrupt.
Surface marked by rather strong, rounded concentric ridges and fur- rows that are nearly obsolete on the posterior umbonal slope.
FOSSILS OF THE DEVONIAN. 175-
Length of average size specimen, 12"; height, 7™”.
This species is allied to the young shells of Grammysia Hannibalensis Shumard (Pal. N. Y., vol. v, pt. 1, Plates and Explanations, pl. 1xi, figs. 25-3 5), but in the more anterior position of the beaks and small size it differs; it occurs at an horizon about 3,500 feet lower in the strata.
Formation and localities—Upper portion of the Devonian limestone, on Rescue Hill, west of Rescue Canon, and also at The Gate, northwest of Eureka, Nevada.
Genus SANGUINOLITES McCoy. Sanguinolites ? Combensis, n. sp.
Plate xv, fig. 16.
Shell very elongate, the length being about four times the height; moderately convex. Anterior end contracted and uniformly rounded on the lower portion, about one-sixth the entire length of the shell, measuring from the beaks; the nearly straight basal line is interrupted only by the sinuosity caused by the broad byssal furrow at the anterior third of its length; posterior end of the shell somewhat narrowed, terminating in a rather abruptly rounded extremity on the upper portion of the posterior outline; cardinal line straight anteriorly, becoming slightly arcuate on the posterior third.
Surface marked by numerous concentric lines of growth.
The generic reference of this species is somewhat provisional, as there is but one imperfect right valve in the collection, which, although strongly characterized, does not give the hinge structure, and other important feat- ures of value in generic determinations.
Formation and locality —Lower Devonian, Combs Peak, Eureka District, Nevada.
Sanguinolites? gracilis, n. sp.
Plate iv, fig. 10.
Shell slender, elongate. General surface moderately convex, the upper margin reflected, forming a slightly concave lunette along nearly the entire length of the hinge, which is a little shorter than the length of the shell. Beaks small near the anterior end and slightly incurved.
Ps 176 PALEONTOLOGY OF THE EUREKA DISTRICT.
Surface nearly smooth, a few obscure lines of growth alone showing on the cast or matrix.
The anterior adductor muscular scar is of medium size, and has a low ridge and sulcus posterior to it that start near the beak and extend nearly to the basal margin.
Dimensions: height at anterior end, 1.75; near posterior end, 2°"; length, 11°.
This form differs from the preceding species in its more slender form, the absence of a well-defined byssal furrow, and the more attenuate anterior extremity.
Formation and locality—Lower Devonian of Brush Peak, Eureka Dis- trict, Nevada, and also at the same horizon on Lone Mountain, 18 miles northwest of Eureka, Nevada.
Sanguinolites rigidus W. & W. (Sp.) Plate xvi, fig. 6.
Oypricardia? rigida White & Whitfield, 1862. Proc. Boston Soe. Nat. Hist., vol. viii, p. 300. Edmondia? bicarinata Winchell, 1863. Proc. Acad. Nat. Sci. Philad., vol. xv, p. 13. Sanguinolites rigidi Hall, 1870. Prelim. Notice Lam. Shells, p. 44. rigidus Hall, 1883. Pal. N. Y., vol. v, pt. 1, Plates and Descriptions, p. 16; pl. lxvi, figs. 1-19.
The relative stratigraphic position of this species in the Chemung Group of New York and the Upper Devonian beds of The Gate, northwest of Eureka, is the same; and direct comparison with specimens from the Burlington sandstones of Iowa and the Chemung shales of New York, shows
the two forms to be specifically identical.
Sanguinolites ? Sanduskyensis Meek. Plate v, fig. 4.
Sanguinolites? Sanduskyensis Meek, 1871. Proc. Acad. Nat. Sci. Philad., vol. xxiii, p. 68. Ibid., 1873. Geol. Surv. Ohio Pal., vol. i, pt. 2, p. 209, pl. xviii, fig. 3.
Compare Modiomorpha linguiformis Hall. Pal. N. Y., vol. v, pt. 1, Plates and Descrip- tions, p. 12, pl. xxxiv, figs. 15-17, and M. Hyalea, p. 13, pl. xli, fig. 28.
The external form and characters of the shell before me agree with those described by Mr. Meek, as shown in his figure.
FOSSILS OF THE DEVONIAN. 177
In making an original generic reference, I would place the species under Modiomorpha, as it is more closely related to the genus as defined by Pro- fessor Hall (Prelim. Notige Lam. Shells, 1870. 8vo., pam., p. 72) than to Sanguinolites, as restricted by him to American species. For the present, Mr. Meek’s provisional reference is retained.
Formation and locality—Lower Devonian of Atrypa Peak, Eureka Dis: trict, Nevada.
Sanguinolites ventricosus W. & W. (Sp). Plate xv, fig. 13. Orthonota ventricosa White & Whitfield, 1862. Proc. Boston Soc. Nat. Hist., vol. viii, p. 297. Sanguinolites ventricosus Miller, 1877. Cat. Amer. Pal. Foss., p. 203. Hall, 1883. Pal. N. Y., vol. v, pt. 1; Plates and Descriptions, p. 16, pl. xvi, figs. 36-42.
The Nevada shell possesses all the specific characters of the examples of this species from the Burlington sandstone of Iowa, differing only in the more angular umbonal ridge, and not quite as expanded posterior end; features reduced or enlarged by the nature of the sediment in which the shells are embedded. A species referred to this from the Chemung Group of New York has sharp concentric lines instead of the more rounded lines of the Burlington species.
Formation and locality—Middle to Upper Devonian, Rescue Hill, west of Rescue Canon, Eureka District, Nevada.
Genus CONOCARDIUM Bronn. Conocardium Nevadensis, n. sp.
Plate xvi, figs. 4, 4a.
Shell small, cordate when viewed from the anterior end, and subtrig- onal on a side view; anterior half ventricose, sloping away rapidly to the narrow posterior extremity and obliquely truncate anteriorly, the anterior slope being more or less concave below the rounded umbonal angle; beaks rising above the hinge-line, incurved; hinge-line straight, forming an angle of about 80° with the posterior, and 110° with the anterior, margin; hiatus
not observed in the united valves, but from the outline of the single valve wWcvDw
178 PALEONTOLOGY OF THE BUREKA DISTRIOT.
it was of medium width, and nearly one-half the length of the shell on the lower side.
Surface marked by fine radiating strie on the body and anterior slope, and stronger strize or ribs on the alate posterior portion of the shell; traces of fine concentric striz are discernible, which under more favorable conditions of preservation would probably be a prominent feature. ;
This species is allied to a form from the Schoharie grit of New York, but with its short ventricose body, slender posterior extension, and rounded umbonal angle it differs from any described Devonian species known to me.
Formation and localities—Lower Devonian horizon of Gray’s Canon, and Comb’s Peak, Eureka District, Nevada.
Genus PARACYCLAS Hall. Paracyclas occidentalis H. & W. Lueina (Paracyelas) elliptica, var. occidentalis. Hall & Whitfield, 1872. Twenty-fourth Ann. Rep. N. Y. State Museum Nat. Hist., p. 189. Twenty-seventh, ibid., : pl. xii, figs. 14-16, 1875. Paracyclas elliptica, var. occidentalis Hall. Pal. N. Y., vol. v, pt.1; Plates and Expla- nations, p. 18, pl. lxxii, figs. 31-33.
The specific resemblance of the Nevada to the Ohio shell is so close that when placed in the same tray it is difficult to separate the two except by lithologic characters.
It has a much greater vertical range in Nevada than in Ohio, occurring near the base and the summit of the Devonian, and in Ohio only at the Upper Helderberg horizon.
Formation and localities —Lower Devonian of Lone Mountain; Middle and Upper Devonian of Rescue Hill, west of Rescue Camion, and at The Gate, northwest of Eureka, Nevada.
Genus POSIDONOMYA Bronn. Posidonomya levis, n. sp. Plate iv, fig. 6. Shell thin, broadly truncato-ovate. General surface depressed and but very slightly convex towards the beak on the rounded umbonal slopes.
FOSSILS OF THE DEVONIAN. 179
Hinge-line straight, not quite as long as the greatest width of the shell. Beaks small, situated on the posterior portion of the anterior half of the shell, and nearly but not quite emarginate.
Surface marked by traces of a few concentric lines of growth. No interior characters have been observed.
Dimensions : height, 2.25°; breadth, 2.5°™; convexity of right valve at the umbo, 2.5™™.
In its smooth surface this species varies from typical examples of Posidonomya, but its straight hinge-line and general form ally it more nearly to that genus than to any other with which I am acquainted.
Formation and locality—lLower Devonian of Atrypa Peak, Eureka Dis- trict, Nevada, also at the same horizon on Lone Mountain, 18 miles north- west of Eureka, Nevada.
Posidonomya Devonica, n. sp.
Plate iv, fig. 7.
Shell thin, small, obliquely truncato-ovate. General surface very much depressed. Hinge-line straight. (Owing to the breaking away of the ante- rior portion this is not certain, but if any deflection from a straight line oceurs it is very slight). Beaks small, situated near the cardinal margin at the anterior third of the distance between the posterior and anterior margins.
Surface marked by strong concentric lines that terminate on the straight cardinal line.
Interior and hinge characters unknown.
Dimensions: height, 14™"; breadth, 13™"; convexity of right valve, 1.5™.
This species occurs at the same locality as the preceding, but not in the same layer of rock. It differs in form and surface markings, in the latter feature more closely resembling the typical forms of the genus than P. levis.
As with P. levis, we know nothing of the hinge-line or interior char- acters, and have only the general form to go by in making the generic reference, which renders it more or less provisional and doubtful. Com- paring this species, however, with Posidonomya Bronni Voltz, from the
180 PALEONTOLOGY OF THE EUREKA DISTRICT.
Lias (Pictet. Traité de Pal., Atlas, pl. Ixxxii, fig. 14), there is a striking resemblance.
Formation and locality—lLower Devonian of Atrypa Peak, Eureka Dis- trict, Nevada, and also at the same horizon on Lone Mountain, 18 miles. northwest of Eureka, Nevada.
Genus MICRODON Conrad.
CYPRICARDELLA Hall.
Microdon (C.) macrostriatus, n. sp. Plate v, fig. 5.
Shell transverse, broadly subovate. General surface depressed, very slightly convex. Hinge-line more than half as long as the shell. Beaks small and situated on the anterior quarter of the shell.
Surface marked by strong concentric lines of growth, seven in a dis- tance of 12™ on the central portion of the shell.
Dimensions: height, 2™; length about 4°”.
In general form this species is not unlike Microdon complanatus Hall (Pal. N. Y., vol. v, pt. 1, Plates and Explanations, pl. Ixxiv, figs. 14-19). The beaks are more anterior and the surface strize more like lines or short, sharp undulations of growth than fine striz.
The anterior half of the shell is preserved on one specimen, the out- lined portion of fig. 5 being taken from another, in which the shell in front of the beaks is broken away.
Formation and locality—Lower Devonian of Atrypa Peak, Eureka Dis- trict, Nevada; also at the same horizon on Lone Mountain, 18 miles north-
west of Eureka, Nevada.
Genus ANODONTOPSIS McOoy. Anodontopsis amygdaleeformis, n. sp. Plate xv, figs. 7, 7a, b.
General outline obscurely subtrigonal, moderately convex; slope from below the beaks to the anterior extremity slightly concave, and from this
FOSSILS OF THE DEVONIAN. 181
point, which is above the transverse center of the shell, the outline curves down into the broadly-rounded basal margin; posterior extremity a little below the transverse center and broadly angular, the line above rounding upward into the cardinal line and to the beaks with a uniform curvature; beaks elevated above the hinge-line, rather small, and situated on the ante- rior third of the shell.
Surface of cast with an obscure anterior muscular scar and obscure concentric lines of growth.
In the absence of the structure of the hinge the generic reference is ac- companied with more or less uncertainty, but in the light that the present specimens afford the species is referred to the genus Anodontopsis.
Formation and localities —Lower Devonian horizon of Lone Mountain, 18 miles northwest of Eureka; and Gray’s Canon, Kureka District, Nevada.
Genus SCHIZODUS King. CYTHERODON Hall. Schizodus (Cytherodon) orbicularis, n. sp. Plate v, figs. 8, 8a.
Shell of medium size; suborbicular, or subrhomboidal in outline. Gen- eral surface strongly convex, with the umbonal ridge rounded. Beaks smail and but little elevated above the cardinal line.
Surface smooth or marked by slightly impressed concentric lines of growth. Interior characters unknown.
Dimensions: height, 3°"; breadth, 3.5°™; convexity of right valve, .75™.
A small shell (fig. 8a) still more quadrate in outline occurs in the Lower Devonian of Atrypa Peak. It is probable that it is a young shell of the species under consideration.
In Cytherodon (Schizodus) quadrangularis Hall (Pal. N. Y., vol. v, pt. 1, Plates and Explanations, p. 18, pl. xxv, figs. 31-36), from the Chemung and Waverly Groups, we have the nearest form to S. (C.) orbicularis.
The beaks in the former are more subcentral and the outline less sub- orbicular. They are, however, very closely allied species.
Formation and locality—lLower Devonian of Lone Mountain, 18 miles northwest of Eureka, Nevada.
182 PALEONTOLOGY OF THE EUREKA DISTRICT.
Genus CYPRICARDINIA Hall. Cypricardinia indenta Conrad (Sp.). Plate v, fig. 14; pl. xv, fig. 11.
Cypricardites indenta Conrad, 1842. Jour. Acad. Nat. Sci. Philad., vol. viii, pt. 2, p. 244, pl. xii, fig. 12. inflata Conrad, 1842. Ibid., p. 246, pl. xv, fig. 2.
Cypricardinia inflata, var. subequivalvis Hall-& Whitfield, 1872. Twenty-fourth Ann. Rep. N. Y. State Museum Nat. Hist., p. 189. Jdem, Twenty-seventh Ann. Rep., 1875, pl. xi, figs. 2-4.
indenta Hall, 1883. Pal. N. Y., vol. v, pt. 1; Plates and Explanations, p. 19, pl. Ixxix, figs. 6-23.
~
The Nevada specimens agree closely with those from New York and the Falls of the Ohio, no apparent variations occurring in a number of speci- mens except, it may be, in some young shells, a figure of one of which is given on plate v, fig. 14.
Formation and locality—Lower Devonian of Atrypa Peak. Eureka Dis- trict, Nevada.
GASTEROPODA. Genus PLATYCERAS Conrad.
Of the eight species of Platyceras from the Lower Devonian horizon, five are identical with species of the Upper Helderberg Group of New York, viz: Platyceras carinatum Hall, P. conicum Hall, P. dentalium Hall, P. nodo- sum Conrad, and P. Thetis Hall (for descriptions and synonyms, see Pro- fessor Hall’s beautiful monograph of the Devonian Gasteropoda of the State of New York, Pal. N. Y., vol. v, pt. 2, 1879), and three appear to be distinct from any described forms.
Platyceras Conradi, n. sp. Plate xvi, figs. 1, La. Shell strongly arcuate, the apex incurved, oblique, and resting against the right side of the body whorl; body whorl increasing very gradually in size from the inner whorl to the aperture; prominent on the back and some-
FOSSILS OF THE DEVONIAN. 183
what flattened on the left side. Aperture varying from irregularly quadrate to subquadrangular; peristome sinuous and in some examples marked by a prolongation of the dorsal side and a strong sinus on the right posterior margin, which in other specimens is quite shallow and carried back on the posterior margin.
Surface, as shown by the cast, strongly striate, parallel to the margin of the peristome, and marked by undulations of growth on the body whorl.
This species is allied to P. Thetis Hall (Pal. N. Y., vol v, pt 2,p. 8, pl. iii, figs. 11-16) in the general form of the body whorl, but differs widely in its more oblique, arcuate upper portion, a feature distinguishing it from 1’. symmetricum Hall (loc. cit., p. 9, pl. iti, figs. 17-25) and other allied species.
Formation and locality—Lower Devonian horizon of Comb’s Peak, Eu- reka District, Nevada.
Platyceras nodosum Conrad. ‘ Plate vi, figs. 5, 5a, b. Platyceras nodosus Conrad, 1841. Fifth Ann. Rep. Pal. State of N. Y., p. 56. nodosum Hall, 1859. Pal. N. Y., vol. iii, p. 473, pls. exv, figs. 1-6; exvi, figs. 1-4. dumosum and P. dumosum, var. rarispinum Hall, 1876. Pal. N. Y., [lustra- tions of Devonian Fossils, Gasteropoda, plates v and vii. nodosum Hall, 1879. Pal. N. Y., vol. v, pt. 2, p. 17, pl. vii, figs. 4, 5.
We have very little hesitancy in identifying the species from Lone Mountain with specimens from the Oriskany sandstone of Knox, N. Y., and the figures of P. nodosum given by Professor Hall. The Nevada shell may expand a little more rapidly along the inner volutions, but of this there is scarcely any proof. The general form and nodose character of the surface vary little from the same features in the New York specimens; not as much as the specimens from the same locality vary from each other.
In New York the species ranges from the Oriskany sandstone to the Upper Helderberg Group. In Nevada it is as yet known only from the Lower Devonian in association with other Upper Helderberg species.
Formation and locality—lLower Devonian of Lone Mountain, 18 miles northwest of Eureka, Nevada.
184 PALEONTOLOGY OF THE EUREKA DISTRICT.
Platyceras undulatum, n. sp. Plate vi, figs. 2, 2a.
Shell small, depressed; apex incurved; body whorl expanding quite rapidly on the outer half of the volution; dorsum subangular and with a shallow depression on each side; a second rounded carina appears on the left side. The body volution is marked by concentric undulations that are slightly sinuous; on the dorsal carina a node appears at the crossing of the undulations. Aperture subcircular; peristome sinuate; the undulations corresponding to the outline of its margin.
Surface of shell unknown.
There is but one specimen of this species in the collections, but it is so well distinguished by its general form and the presence of trans- verse undulations that there is little danger of confusing it with other spe- cies It is of the same type as Platyceras Newberryi Hall (Pal. N.Y., vol. iii, p. 333, pl. Ixiii, figs. 14 a-e) of the Lower Helderberg Group, and the undulations in the cast may owe their origin to the presence of rows of nodes or spines on the shell.
Formation and locality—Lower Devonian, Brush Peak, Eureka Dis- trict, Nevada.
Platyceras thetiforme, n. sp. Plate vi, figs. 4, 4a, b.
Shell obliquely arcuate from the base with the apex incurved, the nu- cleus making about one volution; body whorl gradually increasing in size to the aperture; on the back it is strongly carinate; the left side is evenly rounded and the right a little flattened, producing a slight carina where uniting with the anterior surface.
Form of aperture unknown. Surface markings not determined. The strong carina on the back distinguishes this species from P. Thetis Hall, and its gradually expanding body volution, so much like that of P. Thetis, from P. carinatum.
Formation and locality — Lower Devonian of Brush Peak, Eureka Dis- trict, Nevada, in association with Platyceras Conradi, Platyostoma lineatum, etc.
FOSSILS OF THE DEVONIAN. 185
Genus PLATYOSTOMA Conrad.
Platyostoma lineatum Conrad.
Platyostoma lineata Conrad, 1842. Jour. Acad. Nat. Sci. Philad., vol. viii, p. 276, pl. xvii, fig. 7. Hall, 1876. Pal. N. Y., Illustrations of Devonian Fossils, Gas- teropoda, pl. ix, figs. 1-21; Idem., Pal. N. Y., vol. v, pt. 2, p. 21, pl. x, figs. 1-21, 1879.
The only differences to be noted between the Nevada shells and those of this species from the Upper Helderberg and Hamilton Groups of New York are, that the former average a little less in size and the surface can- cellation, formed by the crossing of the revolving and concentric striz, is almost obsolete; this latter feature, however, is frequently seen in speci- mens from both the New York formations.
Formation and locality—lLower Devonian of Comb’s Peak, Eureka District, Nevada.
Genus EUOMPHALUS Sowerby. Euomphalus Eurekensis, n. sp. Plate xvi, figs. 2, 2a.
Shell large, discoidal, lower side broadly umbilicate. Volutions four or more, nearly in the same plane, varying somewhat in different individu- als; barely contiguous, gradually and uniformly expanding from the apex; section subcircular or transversely subovate, the diameters being as 4 to 5, to the outer portion of the last volution where there is a slight angularity developed on the upper, outer margin. Aperture slightly expanded, with a slight sinus on the upper margin. ’
Surface marked by concentric striz parallel to the margin of the aper- ture.
The largest individual observed of this species has a transverse diam- eter of 80™", measuring across the volutions. The inner volutions have been decollated or removed during the maceration of the shell, leaving only the outer volution and one-half of the next preceding it, the termi- nation of which rises slightly above the plane of the outer volution. A specimen 55™ across the volutions has the spire depressed to the plane of
186 PALEONTOLOGY OF THE EUREKA DISTRICT.
the periphery of the outer volution, and in another it is still more depressed, the umbilicus being nearly flat.
Formation and localities —Lower horizon of the Devonian limestone, Comb’s Peak, and Atrypa Peak Ridge, Eureka District, Nevada.
Buomphalus (Phanerotinus) laxus Hall.
Plate vi, fig.3.
Euomphalus lawus Hall, 1861. Descriptions of New Species of Fossils, ete., p. 26. 1862. Fifteenth Ann. Rep. N. Y. State Cab. Nat. Hist., p. 54, pl. vi, fig. 2. (Eceuliomphalus?) lavus Hall, 1876. Pal. N. Y., lustrations of Devonian Fossils, Gasteropoda, pl. xvi, figs. 16-18. comes Hall, 1876. TIbid., pl. xvi, figs. 8, 9. (Phanerotinus) lacus Hall, 1879. Pal. N. Y., vol. v, pt. 2, p. 60, pl. xvi, figs. 8, 9, 16-18. Compare Phanerotinus paradoxus Winchell, 1863. Proc. Acad. Nat. Sci. Philad., vol. xv, p. 21.
The representatives of this species from the Upper Devonian are smaller than the average-sized specimens from the Hamilton Group of New York. In the disjoitied volutions, broadly umbilicated under-side, gradual expansion from the apex, circular section, and concentric surface striz, the species is identical with Z. lacus.
It seems somewhat improbable that a form of this character should range from the Upper Helderberg and Hamilton Groups of New York up to the summit of the Devonian in Nevada, but with the large number of species which we know are common to the two localities and the identity in form between the shells of this species from each locality, there appears no other way than to place them under the same specific name.
There is a species associated with Z. lavus that corresponds closely to Evomphalus (S.) Hecale Hall, (Pal. N. Y., vol. v, pt. 2, p. 59, pl. xvi, figs. 10-14), from the Chemung Group of New York and Pennsylvania, the difference being in the more rapid expansion of the outer volution. The specimens at hand are too imperfect for specific description.
Formation and locality—Upper Devonian; The Gate, northwest of Eureka, Nevada.
FOSSILS OF THE DEVONIAN. 187
Genus ECCULIOMPHALUS Portlock.
Ecculiomphalus Devonicus, v. sp. Plate vi, figs. 6, 6a.
Shell discoid. Volutions, one or two?, widely separated; rapidly enlarging; section subtriangular, rounded a little above and also from the inner and outer margins down to the obtusely angulated ventral surface.
Surface unknown.
A comparison with the figures given by Portlock of the types of the genus EH. Bucklandi and E. minor (Rep. Geol. Londonderry, Tyrone, &c., 1847, pp. 411, 412, pl. xxx, figs. 10-12) shows our Devonian species to be generically identical with them, although the inner portion of the whorl or whorls is broken away, and the surface of the shell destroyed.
Formation and locality—Lower Devonian of Atrypa Peak; Eureka District, Nevada.
Genus STRAPAROLLUS Montfort. Straparollus Newarkensis, n. sp. Plate xvi, figs. 7,7 a.
Shell small; spire slightly elevated above the general plane Umbili- cus narrow, scarcely exposing the inner whorls. Volutions four or five, very gradually expanding to the outer volution, which increases a little more rapidly; transverse section rounded, subangular or obscurely subquad- rangular; obtusely angular above and below with a slightly oblique, convex, or flattened periphery; gently rounded on the upper surface to the strongly defined suture, and on the lower surface to the more sharply rounded edge of the umbilicus.
Surface of the shell marked by concentric striz and lines of growth parallel to the margin of the aperture. From the suture they curve slightly backward over the upper margin, and then forward to a little below the center of the periphery, recurving gently backward to the margin of the umbilicus.
188 PALEONTOLOGY OF THE EUREKA DISTRICT.
This species is closely related to several described forms, but differs chiefly in having an unusually narrow umbilicus.
Formation and locality—Central portion of the Devonian limestone; Newark Mountain, Eureka District, Nevada.
Genus PLATYSCHISMA McCoy. Platyschisma? McCoyi, n. sp. Plate xvii, figs. 1, la-e.
Shell subdiscoidal in its younger stages of growth, becoming more or less trochiform in the adult; spire moderately elevated. Volutions five or six, expanding gradually from the apex to the aperture; periphery rounded, acute; upper surface with a distinct depression just above the periphery, that increases in width with the enlargement of the volutions so as to give, in the adult, a concavity to the surface of the last volution; under side of yolutions slightly convex; transverse section subrhombic. Aperture irregu- larly rounded with a sinuosity in the upper margin.
Surface marked by lines of growth that curve back to a narrow line or band, and then forward to the periphery of the whorl; on the last whorl these lines have a broad retral curve from the periphery to the umbilicus.
This species differs from the generic type of Platyschisma in having a closed umbilicus, and thick shell, but in the typical species the umbilicus is very small, and M. Chenu has placed a thick shell, P. applanatus,” as representing the genus. In other respects the generic characters are those of Platyschisma, the narrow line formed by the meeting of the striz not forming a true band as in Pleurotomaria.
Formation and locality—Central portion of the Devonian limestone ; Newark Mountain, Eureka District, Nevada.
Platyschisma? ambiguum, n. sp. Plate xvii, figs. 3, 3a. Shell subdiscoidal, spire short, obtuse. Volutions about five, angular and closely united at the suture, forming a slightly convex, unbroken slope
12Mannal de Conchyliologie, p. 235, fig. 1382, 1859.
FOSSILS OF THE DEVONIAN. 189
from the apex to the acute periphery; transverse section subtrigonal; upper surface with a slight depression below the center; under surface slightly convex. Umbilicus closed. Aperture nearly round, with the inner lip reflected.
Surface transversely marked by lines of growth that have a retral curve on the central portion of the upper surface of the volution.
This species is doubtfully referred to Platyschisma, owing to its having a reflected inner lip and closed umbilicus. The latter, however, was prob- ably open in the earlier stages of growth, having been closed by the outer volutions. The general aspect of the species is much like that of several forms of Pleurotomaria occuring in the Silurian formations, but the absence of a definite mesial band and the presence of the broad sinuosity in the upper portion of the aperture, shown by the.retral curve of the lines of growth, distinguishes it and places its generic relations with Platy- schisma or an allied genus.
Formation and locality —Upper horizon of the Devonian limestone, The Gate, Eureka District, Nevada.
Genus CALLONEMA Hall. Callonema occidentalis, n. ‘sp.
Plate xvi, figs. 3, 3a.
Shell subglobose, depressed. Spire slightly elevated, consisting of about four rounded volutions very regularly increasing in size from the apex to the aperture; suture slightly depressed and marking the periphery of the preceding volutions.
Surface exfoliated. The cast shows a few obscure transverse striz that curve gently backward from the suture towards the periphery.
The general aspect of this species is similar to that of Callonema imitator H. and W. (Hall, Pal. N. Y., vol. v, pt. 2, p. 53, pl. xiv, figs. 16, 17) of the Upper Helderberg Group of the State of Indiana. It differs in having a more depressed spire, and the volutions expanding a little more rapidly.
Formation and locality—lLower horizon of the Devonian limestone, Comb’s Peak, Eureka District, Nevada.
190 PALEONTOLOGY OF THE EUREKA DISTRICT.
Genus LOXONEMA Phillips.
Casts of five species of spiral univalves occur in the lower fossiliferous beds of the Devonian limestone. They are in such a condition of preserva- tion as to render it difficult in the absence of surface-markings to determine their relations, although they evidently belong to the genus Loxonema. Professor Hall met with a group of species in the Upper Helderberg Group of the State of New York in a similar condition, and assigned specific names to those differing widely in form and proportions from those already de- scribed so as to be distinguished by these characters alone. This course is the only one to pursue with such meager and unsatisfactory material when it is desirable to specify the different forms, and as this is the case with the Nevada species, two of the five are described and referred to Loxonema, and a descriptive note given with each of the remaining three, one of which is provisionally referred to Loxonema subattenuata, of the Upper Helderberg Group of New York.
Loxonema Hurekensis, h. sp.
Plate xvi, fig. 8.
Shell turretiform, elongate, robust; spire somewhat rapidly ascending, angle of divergence from the apex, 25°. Volutions, eleven or more in a specimen of 110"™ in length, slightly convex, and very gradually expand- ing from the apex.
Surface unknown.
Formation and locality—lLower horizon of the Devonian limestone; divide at the head of the Reese and Berry Canton, Eureka District, Nevada.
Loxonema nobile, n. sp.
Plate xvi, fig. 9.
Shell robust, elongate, turretiform; spire rapidly ascending, angle of divergence from the apex, 15°. Volutions regularly increasing from the apex, slightly convex ;\ the three lower volutions have a united length of
ORS
FOSSILS OF THE DEVONIAN. 191
This and the preceding species have slight indications of uninterrupted concentric lines of growth, so that the generic reference will probably be sustained on the finding of more perfect specimens. They are large, robust forms, differing very much from each other and from any described species occuring at the same geologic horizon.
Formation and locality.—Lower horizon of the Devonian limestone, Comb’s Mountain, Eureka District, Nevada.
Loxonema ? subatteruatum Hall ?
Loxonema subattenuata Hall, 1861. Descriptions of New Species of Fossils, ete., p. 24. Tdem., 1862. Fifteenth Ann. Rep. N. Y. State Cab. Nat. Hist., p. 52. Idem., 1876. Pal. N. Y., Illustrations of Devonian Fossils, Gasteropoda, pl. xiii, figs. 1-3. Idem., 1879. Pal. N. Y., vol. v, pt. 2, p. 40, pl. xiii, figs. 1-6. The illustrations of this species in the Paleontology of New York do not show the surface characters, which restricts the comparison to the casts; among these the differences between the two, L. subattenuatum and the Ne- vada form, are so slight as to make it impossible to separate them on good specific characters. The species occurs at Comb’s Peak, in the Lower Devonian, and at the same relative horizon in Gray’s Canon, Kureka District, Nevada.
Loxonema approximatum, n. sp. Plate vi, fig. 7.
Shell, terebriform; spire rapidly ascending, volutions slightly convex, increasing regularly from the apex, the last one a little vertical; six in the length of 24 inches from the base. Aperture subelliptical.
Surface as shown on the inner cast, marked by moderately strong, not closely arranged, longitudinal striz that are nearly transverse to the volu- tions; the striz arch backward very slightly.
The description of this species is nearly identical with that of Loxone- ma styliola Hall (Pal. N. Y., vol. v, pt. 2, p 48, pl. xiv, figs. 8, 9) from the Chemung Group of New York. It differs only in the more elongate form
192 PALEONTOLOGY OF THE EUREKA DISTRICT.
of the volutions and the presence of stronger surface striz, as shown in the cast. The specific distinction is made on the difference in form of the volu- tions.
Formation and locality—Lower Devonian of Atrypa Peak, Eureka Dis-
trict, Nevada. Loxonema ? (sp. undt.)
Shell turretiform, elongate; angle of divergence from the apex, 13° to 15°. Volutions gradually enlarging, broad, moderately convex. Surface unknown.
This species is represented by a fragment preserving three of the lower volutions. It is distinguished by its elongate, tapering spire, and broad vo- lutions, resembling in this respect Loxonema nobile, but differmg in the
greater convexity and form of the volutions.
Loxonema (sp. undt.)
Shell terebriform. Spire rapidly ascending; angle of divergence about 12°. Volutions narrow, rounded, gradually expanding. Surface obscurely shown by faint striz, which hend slightly backward a little below the suture and make a gentle curve forward to the base of the volution.
This and the preceding species are associated with Loxvonema? subat- tenuatum ? and Bellerophon perplexa, in the lower fossiliferous horizon of the Devonian limestone of Gray’s Canon, Eureka District, Nevada.
Genus BELLEROPHON Montfort.
Of the six species represented in the collections from the Devonian limestone, two are undescribed and four are either identical with species described by Professor Hall, from the Devonian strata of the State of New York, or so closely allied to them that the grounds for a specific separation are not apparent in the specimens at hand. With a large number of more perfectly preserved specimens for comparison, it may be that some of the identifications will prove to be incorrect and to have been based on insufti-
cient material.
FOSSILS OF THE DEVONIAN. 193
Bellerophon perplexa, n. sp.
Plate xvii, figs. 6,6 a, b.
Shell subglobose, the transverse and lateral diameters being 27™™ and 33™™, respectively, in a medium-sized specimen. Volutions five or six, broadly rounded on the dorsum, subangular on the dorso-lateral angle of each volution, and sloping rapidly into the broad, open umbilicius from the dorso-lateral angle. Each volution embraces the dorsal surface of the pre- ceding, leaving the entire umbilical slope of each exposed. The extreme transverse section of each volution is equal to four times the lateral section as it is measured midway, or at the carina. The aperture is probably sim- ilar in form to the transverse section of the last volution, as in a number of examples examined no evidence of any expansion was observed. The dor- sum has a narrow, well-defined carina.
Test varying in thickness from .75™" to 1.50™™, with the variation in the size of the shell.
Surface marked by strong striz; originating on the inner margin of the umbilical lobe they cross it obliquely, curving slightly and extending back- ward at an angle of 45° to the dorso-lateral angle over which they curve, retaining a backward slope of 15° to the dorsal carina.
The largest specimen in the collection has a transverse diameter of 50™, The test is removed from the outer portion of the last volution, the mold retaining only the slight dorsal carina, a feature that in another speci- men is obsolete; this, however, is rarely the case as in most examples it occurs on the outer volution and may be traced on breaking away the volutions to the second or third, where the transverse diameter is five mil- limeters.
Formation and localities—Lower horizon of the Devonian limestone, Comb’s Peak, Gray’s Canon and Atrypa Peak, Eureka District, Nevada.
Bellerophon Combsi, n. sp. Plate xvii, figs. 9, 9a, b.
Form large, robust, subglobose; exterior shell unknown. In the cast the body volution is large, nearly if not quite concealing the inner volu- tions; broadly rounded on the dorsum and gradually expanding towards
13 0D Ww
194 PALEONTOLOGY OF THE EUREKA DISTRICT.
the transversely ovate aperture; a narrow dorsal carina is distinctly shown on the cast, and, very obscurely, traces of transverse striz.
This is the largest of the several species occurring in the Devonian limestone of Nevada. Its length is 48""; transverse section midway of the outer volution 30", near the aperture 45™™.
Formation and locality—Lower horizon of tl¥e Devonian limestone, Comb’s Peak, Eureka District, Nevada.
Bellerophon lyra Hall (Pal. N. Y., vol. v, pt. 2, p. 113, pl. xxiii, figs. 1, 17-20).
A single specimen that corresponds in form and surface markings to this species occurs in the Devonian limestone on the eastern side of the District. It has been slightly worn by exposure to the weather, but not so
much as to remove the fine, undulating, revolving striz.
Bellerophon Leda Hall (Pal. N. Y., vol. v, pt. 2, p. 110, pl. xxiii, figs. 2-16).
The Nevada form is a little less flattened on the dorsum, and the dorsal carina is more prominent, as are the revolving striz; this, however, is rather the result of a difference in the conditions of preservation than of absolute differences in the shells; the New York specimens usually occurring in the argillaceous shales or shaly limestones have suffered by compression. Bellerophon Mera Hall? (Pal. N. Y., vol. v, pt. 2, p. 119, pl. xxv, figs. 9-14; p!. xxvi,
figs. 19-24).
A fragment from the higher beds south of The Gate has a thick test thickly studded with rows of pustules’ in a manner similar to that of B. Mera of the Chemung Group of the State of New York. The general form of the volutions and dorsal carina also adds to the strength of the
comparison
Bellerophon Pelops Hall? (Pal. N. Y., vol. v, pt. 2, p. 99, pl. xxii, figs. 7-13). Associated with B. Leda, there is a form that corresponds to one of the varieties of this species from the Upper Helderberg limestone of the State of New York. The transverse strie of the surface of the body volution bending backward towards the dorsal carina and the expanded aperture
show in the Nevada specimen.
FOSSILS OF THE DEVONIAN. 195
Genus SCOLIOSTOMA Braun. Scoliostoma Americana, n. sp.
Plate vi, figs. 1, la-e.
Shell small, cylindro-conical exclusive of the expanded inner lip of the aperture; apex obtuse; whorls five, slightly convex Aperture contracted and turned obliquely outward and backward at right angles to the outer surface of the last whorl; outer lip somewhat thickened and rounded; inner lip expanded, extending up on to the whorls and directed outward; a swell- ing occurs opposite the outer lip that occupies its lower central portion; margin of inner lip very thin. Umbilicus concealed. Shell rather thick.
Surface of shell marked by a few concentric strize of growth.
This is a most interesting form, as it is the first species of the genus from American rocks, and its occurrence in the Devonian limestones of Nevada is such that, when finding only a few fragments of the spire, we were led to consider it a land shell, the short, obtuse form recalling species of the genus Pupa.
S. Americana departs somewhat from the typical species S. Dannen- berg Braun 1838, (Neues Jahrbuch, Min. Geo. Geol. und Petrefak, p. 298, taf. ii, figs. B, 1-4) in having the aperture contracted and the inner lip more expanded, but there are no differences that appear to be of more than spe- cific value.
Formation and localities—Lower Devonian of Atrypa Peak, and Brush Peak, Eureka District, Nevada.
This species is associated with Productus subaculeatus, Spirifera undifera, Atrypa reticularis, Goniophora perangulata, Platyceras dentalium, P. carinatum, Bellerophon perplexa, ete.
Genus METOPTOMA Phillips. Metoptoma? Devonica, n. sp. Plate xvii, figs. 2, 2a.
Shell conical, broadly rounded or truncated at the posterior margin;
uniformly rounded on the lateral and anterior margins; apex posterior and
196 PALEONTOLOGY OF THE EUREKA DISTRICT.
terminating within the margin; the slope from the apex is very slightly convex; height a little less than the postero-anterior diameter; test about 1”™™ in thickness.
Surface markings obscured by the exfoliation of portions of the test and the adherence of the matrix; but strong, radiating strize 1™ distant from each other, and a few short undulations of growth, are shown on the postero-lateral faces.
Dimensions: height, 17"™; length, 18""; breadth, 22™™.
Formation and locality—Lower horizon of the Devonian limestone; west side County Peak, Eureka District, Nevada.
PTEROPODA. Genus TENTACULITES Schlotheim.
Of the four species of the genus Tentaculites now known to occur in the lower horizon of the Devonian limestone, three appear to be specifically identical with well-recognized species of the Lower Devonian of the State of New York, while the remaining form is distinguished only by the surface characters, which are often unreliable owing to the imperfect preservation of the test. This is illustrated by Tentaculites gracilistriatus, where, on the same block of limestone, specimens occur preserving the annulations and fine striae, and others on which it is exceedingly difficult to determine either
The species are identified by comparisons with specimens from New York, and also with the beautiful illustrations and careful descriptions in the Paleontology of New York (vol. v, part 2).
Tentaculites gracilistriatus Hall (Pal. N. Y., vol. v, pt. 2, p. 173, pl. xxxi, figs. 12-14, and pl. xxxi A, figs. 37-47).
This neat and strongly defined species occurs in the greatest numbers and is the most widely distributed of the forms found in the Eureka Dis- trict. It posesses all the characters given it by its author in describing the New York types; the variation in the form and prominence of the annula- tions, the solid apical portion devoid of annulations, and the crowded longi-
tudinal striz are the same in each, as also the general form and dimensions.
FOSSILS OF THE DEVONIAN. 197
In New York it is associated with Styliola fissurella, a species that occurs with it at all the localities known in Nevada.
Tentaculites scalariformis Hall (Pal. N. Y., vol. v, pt. 2, p. 167, pl. xxxi, figs. 3-11).
The identification of this species is by the characters of the internal mold, the robust form, and the shape and regularity of the annulations. It has not been observed in association with Styliola fissurella, or other congen- eric species.
Professor Hall states that this species has a geographic range of over 700 miles as known to him, being found in the strata of the Upper Helder- berg limestone in New York, Ohio, and Indiana.
Tentaculites attenuatus Hall (Pal. N. Y., vol. v, pt. 2, p. 170, pl. XxXi, figs. 19, 20).
The Nevada specimens of this species are the same in the character of the surface markings and the irregularity of the annulations on the slender tube, but the species does not appear to have been as gregarious in habit as in the Hamilton Group.
Tentaculites bellulus Hall? (Pal. N. Y., vol. v, pt. 2, p. 169, pl. xxxi, figs. 15-18; and pl. xxxi A, figs. 48-51).
There occur in association with the preceding species a few specimens that are closely allied to 7. bellulus. They have the same numerous, sharp, regular annulations and attenuate tube, but differ in being smaller, and in the absence of the surface markings mentioned by the author of the species.
Genus STYLIOLA Le Sueur.
Styliola fissurella Hall (Pal. N. Y., vol. v, pt. 2, p. 178, pl. xxxi A, figs. 1-30).
It does not appear to be possible to separate this minute form from the species as it occurs in New York. It ranges through the fossil-bearing Devonian limestone from the lower horizon at Lone Mountain to the highest beds at The Gate, northwest of Eureka, Nevada.
Styliola fissurella var. intermittens Hall (Pal. N. Y., vol. v, pt. 2, p. 177, pl. xxxi A, figs. 11-17.)
This elongate form is represented in the upper strata at The Gate,
northwest of Eureka, Eureka District, Nevada.
198 PALEONTOLOGY OF THE EUREKA DISTRICT.
Professor Hall, in speaking of Styliola fissurella, says:
“In its geographical distribution, the S. fissurella has a remarkable range, being known throughout the entire extent of the State of New York from east to west, a distance of more than 300 miles. It also occurs in the State of Indiana, which gives it a geographical extension of more than 700 miles in a direct line from its most easterly locality.
“In some of its phases it does not seem possible to separate this spe- cies from Styliola clavulus of Barrande by any external or internal characters thus far described or illustrated. The fossils are minute, smooth, or striated acicular tubes, presenting in all respects similar features and having similar associations, and they are of the same geological age in the two countries. In very numerous examples these fossils are striated transversely or longi- tudinally, and not unfrequently the two sets of strize are visible on the same specimen. These are apparently only varieties of form and condition of the Styliola fissurella.”
These latter remarks apply in full force to the specimens of this inter- esting species as it occurs in Central Nevada. Here it has the same asso- ciations and is of the same geologic age. It has not been discovered, as far as known, in the interval of 1,600 miles between its former known west- ern extension in the State of Indiana and the present limit. This is, how- ever, largely due to the few localities where the Devonian rocks are ex- posed to examination, and the fact that the great mass of Paleozoic strata west of the Mississippi Valley have been but partially examined by the geolo- gist, and paleontologic investigation has been the result of hasty collecting rather than a systematic study of the fauna of any locality or horizon.
Formation and locality— Upper Devonian limestone, Eureka District, Nevada.
Genus CONULARIA Miller.
Conularia (sp. undt.).
A single fragment was found in the lower beds at Comb’s Peak, but not in a condition to determine its specific relations.
FOSSILS OF THE DEVONIAN. 199
Genus HYOLITHES Eichwald. Hyolithes, sp. (?) Plate vi, figs. 8, 8a.
Form elongate, triangular, tapering regularly and gradually to an acute extremity. Transverse section subtriangular, slightly convex on the ventral side. Dorsal angle obtuse. Breadth and depth as two,to one. Ventral face gently convex, arching slightly from the apex to the aperture Dorsal face with a longitudinal concavity about equal to the convexity of the ventral face; strongly arched transversely. ‘The aperture is not preserved, but was probably oblique, as in allied species.
Surface of shell unknown, as the only two specimens obtained are in the form of casts. This species is very closely allied, if not identical, in general form with Hyolithes aclis Hall (Pal. N. Y., vol. v, pt. 2, p. 197, pl. xxxii, figs 22-30; pl. xxvii A, figs. 23-25) from the Hamilton Group of New York The finding of specimens preserving the shell may show differences that are not now apparent, and for this reason no specific identification is attempted.
Professor Hall calls attention to the small number of species of Hyo- lithes in American Paleozoic strata as compared with other Paleozoic coun- tries, and also the limited geographic range of the American species. All the collections made during the past few years from the Paleozoic formations of the Rocky Mountains and westward have offered no new well-determined forms, and but one species is known at present from above the Cambrian, or first, fauna Owing to the restricted range of the Devonian species of New York, we hesitate to identify this species with 7. aclis, or to define it as a new species, until better specimens are collected.
Formation and locality—Lower Devonian of Atrypa Peak, Eureka Dis- trict, Nevada.
Genus COLEOLUS Hall. Coleolus levis, n. sp.
Plate vi, fig. 9.
Shell an extremely elongate, cylindro-conical, straight or slightly
curved tube; section circular.
200 PALEONTOLOGY OF THE EUREKA DISTRICT.
Surface of both the inner and outer walls smooth.
Dimensions: the largest tube obtained has a length of 11™™ and a diameter of 0.5™".
This species is closely allied to Coleoprion ? Bohemicum Barrande (Syst. Sil. Bohéme., vol. iii, p. 109, pl. xv, fig. 15) trom the Upper Silurian of Bo- hemia.
The surface characters of the Bohemian specimen are unknown, and we would hesitate in identifying a species of this character from the sum- mit of the Devonian in Nevada with one from the Silurian of Bohemia even if more was known of each than is at present
The Nevada species was gregarious, the little slender tubes now lying thickly in the shale; some of them have a smooth, shining surface. The shell is rather thick.
Formation and locality—Upper Devonian, White Pine shale, on the south slope of Diamond Peak, Eureka District, Nevada.
CEPHALOPODA. Genus ORTHOCERAS Breynius.
Five species of Orthoceras are recognized among the numerous frag- ments from the lower horizon of the Devonian limestone. None of them, however, are sufficiently represented to be characterized as specifically dis- tinct from described species, and their further determination, beyond a note of the characters of each, is deferred until more and better material is col- lected.
1. Shell robust, straight, elongate. Transverse section circular in un- compressed specimens. Apical angle about 15°, measuring the septate portion. Chamber of habitation and initial point unknown. Air-chambers numerous and shallow, having a depth of about 5™™ where the diameter is 25". Septa thin, the concavity equal to the interspaces. Sutures gently curved, but not oblique to the axis. Siphuncle central; small at its inser- tion in the septa; its passage through the interseptal spaces has not been observed. Test removed from all observed specimens. There is a large
FOSSILS OF THE DEVONIAN. 201
fragment 45™™ in diameter, preserving three air-chambers, that is closely related to this form; the concavity of the septa is much greater, being 15™".
In some respects these fragments are allied to Orthoceras Bebryx Hall (Pal. N. Y., vol. v, pt. 2, p. 275), of the Hamilton and Chemung Groups of New York, but appear to belong toa distinct species.
II. This is a more slender form than the preceding, and diminishes less rapidly in receding from the chamber of habitation. Transverse section circular. Apical angle, 5° to 6°. Chamber of habitation large, without any constriction as far as observed. Air-chambers numerous, having a depth of 3™" where the diameter of the tube is 13". Septa thin, the concavity equal to a little less than the interspaces. Sutures transverse, straight.
The best preserved specimen is 60™” in length, with a diameter at the septate end of 11™", near the mouth of the chamber of habitation of 16™", the chamber of habitation having a length of 35"". Surface characters un- known. This form is related to Orthoceras exile Hall (Pal. N. Y., vol. v, pt. 2, p. 290), of the Hamilton Group of New York.
III. This fragment has three septa in a length of 25"™; transverse sec- tion slightly ovate, as 8 to 9; greatest diameter, 27™. Apical angle about 5°. Septa thin, with a concavity equal to the depth of the chambers Siphuncle eccentric, distant from the nearest point on the walls of the air-chambers about two-fifths the greatest diameter of the tube. The diameter at the septa is 2™™, where the major diameter of the tube is 18™™.
The greater depth of the air-chambers and the eccentric position of the siphuncele distinguish this from the preceding form.
IV. Several small fragments of an annulated species occur that are not unlike portions of small specimens of Orthoceras Thoas Hall (Pal. N. Y., vol. v, pt. 2, p. 261), of the Upper Helderberg Group. A specimen 7™™ in diameter has seven annulations in a distance of 21"". Septa and siphuncle not observed.
V. Large annulated form, 30°" in diameter. Annulations narrow, de- pressed, with a broad, slightly-depressed area between them, five annula- tions in a distance of 30". The margins of the septa appear about midway between the annulations.
202 PALEONTOLOGY OF THE EUREKA DISTRICT.
There are also a number of elongate, slender tubes, the relations of which have not been determined. They are probably the young of one of the smooth-tubed forms. ;
Formation and localitities —Devonian limestone; Comb’s Peak and Lone Mountain, Eureka District, Nevada.
Genus GOMPHOCERAS Sowerby.
Gomphoceras suboviforme, n. sp. Plate xvii, figs. 8, 8a.
Shell small, subglobose, attenuated towards the apex from the last chamber. Transverse section subcircular. The point of greatest transverse section of the grand chamber is a little anterior to the last septum. Tube expanding regularly, with the sides nearly straight up to the chamber of habitation, where it is somewhat inflated. Chamber of habitation rather large, with the slightly convex ventral and lateral faces sloping gradually to the apertural extremity, while the dorsal face, which is gently concave above the zone of greatest transverse section, is at right angles to the plane of the last septum.
Air-chambers numerous, regular, not perceptibly increasing in depth from where the tube is 10" in diameter to the chamber of habitation; average depth nearly 2™, or ten chambers in a distance of 19". Sutures straight and horizontal. Siphuncle small, situated near the ventral margin; diameter 2™, where the ventro-dorsal diameter of the tube is 17™™; its structural elements are unknown, as the cast shows only the diameter. Internal mold of the tube apparently smooth. Length of chamber of habi- tation (grand chamber), 18""; greatest diameter, 24"; length of tube, em- bracing ten air-chambers, 19""; anterior diameter of last chamber, 22"; of first apical chamber preserved in the specimen, 10™".
This species is distinguished from G. oviforme Hall (Pal. N. Y., vol. v, pt. 2, p. 344) of the Upper Helderberg Group of New York, by the more attenuated and less ovate form, and the uniform and more shallow cham- bers. It also resembles G. raphanus Hall (loc. cit., p. 347), of the Hamilton
FOSSILS OF THE DEVONIAN. 203
Group. The latter is more slender, and has a less gibbous chamber of habi- tation.
Formation and locality—Upper horizon of the Devonian limestone; The Gate, northwest of Eureka, Eureka District, Nevada.
Genus CYRTOCERAS Goldfuss. Cyrtoceras Nevadense, n. sp. Plate xvii, figs. 7, 7a.
This species is represented by a portion of the chambered tube 30™™ in length; the apical extremity, beyond a diameter of 10™", and the cham- ber of habitation having been broken away.
Shell small, regularly curved, the depth of the arc of curvature being 2m in a length of 30™. Transverse section subcircular, Apical angle of the lateral faces about 10°. Air-chambers numerous, varying in depth from 2m to 3™" in a distance of 30", the larger extremity having a depth of 17" and the apical section of 10". Septa smooth, with a concavity a little less than the depth of the air-chambers. Sutures horizontal, with a slight backward curvature on the dorsal side. Siphuncle central. Test thin.
Surface marked by lines of growth that have a somewhat obtuse sinus on the ventral side. The internal mold preserves a trace of the exterior markings of the test.
This species resembles Cyrtoceras (Gomphoceras) metula Hall (Pal. N. Y., vol. v, pt. 2, p. 360), of the Upper Helderberg Group of New York. It differs in the central position of the siphuncle, apical angle, and curvature of the sutures, —
Formation and locality—Lower horizon of the Devonian limestone, Comb’s Peak, Eureka District, Nevada.
Genus GONIATITES De Haan. Goniatites desideratus, n. sp. Plate xvii, fig. 10. Shell discoid; estimating from the depth of the umbilicus, the thick- ness of the disk is about 10". There were probably four volutions; two
£04 PALEONTOLOGY OF THE EUREKA DISTRICT.
are preserved in the specimen before us, with a third partially shown; the outer ones embrace but little of the inner; they are somewhat flattened and apparently sharply rounded on the ventral lobe. Umbilicus wide, exposing all the inner volutions. The volutions enlarge very gradually until towards the outer portion of the last volution, or the grand chamber, where the ex- pansion is slightly increased. ; :
The entire dimensions of the chamber of habitation are unknown, as a portion is broken away and the latter septa are partially concealed by the test; the part remaining, however, indicates that it was large. Four septa are seen on the outer volution, obtained by cutting away a portion of the test; they are thin and uniform, curving a little forward on the umbilical margin and then gently curving backward, including a single broad, flat- tened lobe which occupies the entire width of the volution. Ventral lobe unknown. ‘Test thin.
Surface marked by strong strize and lines of growth that curve forward from the umbilicate lobe, crossing the direction of the septa at an acute an- gle near the umbilical margin and nearly at right angles on the outer por- tion of the volution.
This species differs in its wide umbilicus united with the direction of the surface strize and septa from any form that has come within our obser- vation.
Formation and locality—WPevonian limestone, Comb’s Peak, Eureka District, Nevada.
CRUSTACEA. Genus BEYRICHIA McCoy. Beyrichia (Primitia) occidentalis, n. sp. Plate xvii, figs. 4, 4a.
Carapace large, Leperditia-like in outline, 45™™ in length by 2.75™" in breadth; strongly convex; dorsal margin slightly incurved two-thirds the length of the valves and terminating anteriorly and posteriorly in obtuse angles formed by its union with the anterior and posterior margins ; ventral margin gently curved to its union with the broadly rounded anterior and posterior margins. Two deep and slightly curved sulci penetrate the cen-
FOSSILS OF THE DEVONIAN. 205
tral dorsal region of the valve, terminating about three-fifths the distance across the valve from the dorsal margin; the posterior sulcus is narrow and curves backward, while the anterior is quite broad, with a forward curve, each having its origin on the dorsal margin as a faint groove and deepening with the convexity of the valve; this, united with the opposite curvature of the sulci, forms an elongate lobe or tubercle on the central dorsal portion of the valve; on casts of the carapace, and on valves where the two sulci are united by a slight sulcus at their lower termination, the size and appear- ance of the tubercle is greatly increased; a shallow groove occurs just within the anterior and posterior dorsal angles and extends a short distance down the anterior and posterior margins, where it becomes obsolete; two small, elongate nodes are situated near the dorsal margin, each a little within the anterior and posterior dorsal groove respectively ; the surface of the nodes, the central lobe, and margins of the sulci are smoothly and evenly rounded.
Surface finely granulated, the granules arranged along minute, irreg- ular striz, or lines that radiate from the outer margins of the sulci to the anterior, posterior, and ventral margins.
The presence of the two sulci, as seen in all the adult individuals, properly refers this species to the genus Beyrichia. A study of a series of specimens, however, that pass from the largest size down to individuals 1™™ in length, shows that the posterior suleus becomes more obscure with the decrease in size of the individual, and that when the shell is 1™™ in length the posterior sulcus is obsolete and a true unisulcate Beyrichia results that may be referred to the genus Primitia (plate xvii, fig. 4@). The adult is a member of the corrugate group of Beyrichize, of which Beyrichia Wilckensiana Jones (Ann. and Mag. Nat. Hist., 2d ser., vol. xvi, p.8), pl. v, figs. 17, 18, 1855) is the type, and the young form, of the ‘‘Simplices” of which B. (Primitia) strangulata (Salter) Jones (Ann and Mag. Nat. Hist., 2d ser., vol. xvi, p. 171, pl. vi, fig. 18, 1855; Ibid., 3d ser., vol. xvi, p. 416, 1865), or B. (Primitia) simplex Jones (Quart. Jour. Geol. Soc., vol. ix, p. 161, pl. vii, fig. 7) is the type.
Formation and localities—Lower horizon of the Devonian limestone; Newark Mountain, Eureka District, and Lone Mountain, 18 miles north- west of Eureka, Nevada.
206 PALEONTOLOGY OF THE EUREKA DISTRICT.
In the collections from the White Pine District, this species is found in the Upper Devonian of Telegraph Peak. The specimens all belong to the smaller variety in which the double sinus is almost obsolete.
Genus LEPERDITIA Roualt.
Leperditia rotundata, n. sp. Plate xvi, fig. 5.
Carapace of medium size, 5" in length by 3.5" in breadth; convex, subovate in outline, with the anterior extremity a little narrower than the posterior; dorsal margin straight, about five-sixths the length of the valves; it terminates anteriorly and posteriorly in simple or slightly produced angles formed by its union with the anterior and posterior margins respect- ively; anterior and posterior margins broadly rounded; ventral margin regularly curved and on the right valve turned under, forming a rounded ventral edge to the carapace; ventral valve proportionally narrower than the right, and terminating in a plain edge on the ventral margin.
The uniform convexity of the surface is broken on the anterior and posterior dorsal angles by a slight groove just within the margin, and on the anterior dorsal region by a faintly-defined sulcus, indicating the position of the depressed eye-tubercle; muscular scar a little posterior to the center of the valve, as shown, ona large right valve, by its having a lighter color than the carapace.
Surface smooth to the eye, but minutely punctate under a strong magnifying glass.
Formation and locality—Lower horizon of the Devonian limestone; southeast of Richmond Mountain, Eureka District, Nevada.
FOSSILS OF THE DEVONIAN. 207
PdECILOPODA. Genus PHACOPS Emmerich. Phacops rana Green (Sp.). Calymene bufo, var. rana Green, 1832. Monograph Trilobites North America, p. 42. Phacops rana Hall, 1861. Dese. New Species of Fossils, ete., p. 65. Idem., 1862. Fif- teenth Ann. Rep. N. Y. State Cab. Nat. His., p. 93. Meek & Worthen, 1868. Geol. Sury. IIl., vol. iii, p. 447, pl. ii, figs. 1 a—e. Nicholson, 1875. Pal. Prov. Ontario, p. 125, fig. 5, 6a. Hall, 1876. Pal. N. Y., Illustrations of Devonian Fossils, Crustacea, pl. vii, figs. 1-11; pl. viii, figs. 1-17. Whitfield, 1883. Geol. Wisconsin, vol. iv, p. 339, pl. xxvii, figs. 17-19. Compare Phacops bombijrons Hall. Pal. N. Y., Illustrations Devonian Fossils, Crus- tacea, pl. vi, figs. 18-29.
A comparison of specimens from the Hamilton Group of New York with those from Nevada shows variations that are quite strongly marked, but which are scarcely of specific importance, if we consider that the east- ern form is imbedded in a shale and more or less compressed, while the Nevada examples are in a limestone, and have also undergone slight changes resulting from the differences in their original habitat as compared with the New York specimens. The glabella of the Nevada form is more inflated and protruded in front, a narrow furrow occurs between it and the eye, and the entire head is much more convex, but in one or two specimens these characters are reduced and atypical head of Phacops rana is shown. The species as seen in most of the specimens resembles, in its prominent gla- bella marked in the cast by the little elevations that filled the hollows of the pustules seen in the outer surface of the dorsal shell, Phacops bombifrons, and appears to be a species uniting the latter and Phacops rana.
Formation and localities—Lower horizon of the Devonian limestone; Comb’s Peak and other localities in the Eureka District; also at Lone Mountain, 18 miles northwest of Eureka, Nevada.
Genus DALMANITES Emmerich.”
Dalmanites Meeki, n. sp. Plate xvii, figs. 5, 5 a-c. Dalmanites (undt. sp.) Meek, 1877. Geol. Expl. Fortieth Parallel, vol. iv, p. 48, pl. i, figs. 11, lla.
The general form and the characters of the thorax are unknown, the
208 PALEONTOLOGY OF THE EUREKA DISTRICT.
description of the species being based on portions of the cephalic shield and entire specimens of the pygidium.
The glabella is subclavate, moderately convex, and separated from the fixed cheeks by a well-defined furrow; anterior lobe composing more than half of its entire area, transversely subovate, the length being two-thirds of the width; lateral furrows distinctly defined, deepest at the inner end; the anterior furrow extends obliquely forward and the two posterior pairs have a slight inclination backward; this gives to the anterior lateral lobe a narrow base and wider terminal portion, or a subtrigonal form to the lobe; the two posterior lobes are shorter and with their sides subparallel to each other. Occipital segment slightly rounded, almost flat on the upper portion in the cast, broadest at the center, narrowing slightly towards the dorsal furrows; occipital furrow strongly defined, arching a little forward at the center. Fragments of the fixed cheeks and palpebral lobe, with a free cheek found associated with them, show a large reniform eye situated oppo- site the anterior lateral lobe of the glabella with a deep furrow extending around its base; the slope from the eye to the shallow marginal groove is quite abrupt and gives considerable convexity to the head; the outer margin is of medium width, with a gentle slope outward.
Hypostoma subtriangular, as wide anteriorly as long, moderately con- vex; anterior margin gently curved; lateral margins contract quite rapidly at the anterior lateral angles and then converge regularly to the posterior extremity, where they converge very abruptly, forming an obtuse point which has several short spines or points along its lateral margins; a sulcus that rises on the lateral margin curves backward, and unites with its fellow at the center three-fourths the distance from the anterior to the posterior extremity; a broad shallow groove crosses anterior and subparallel to this, giving a lobed appearance to the posterior half of the hypostoma.
Thorax: A cast of asingle segment is all that occurs associated with the other parts of this species; the median lobe is moderately convex and nearly transverse; lateral lobe curves outward and a little backward, ter- minating in a rather abrupt point; pleural groove deep, crossing the seg- ment obliquely from the anterior margin to the posterior outer angle.
13 Dalmania, Emmerich, 1845; modified by Barrande to Dalmanites in 1852.
FOSSILS OF THE DEVONIAN. 209
Pygidium moderately convex, subtrigonal in outline; length two-thirds of the width; anierior lateral angles a little rounded, lateral margins con- verge with a slight outward curve to the base of a strong upward-curving spine that forms the posterior extremity of the pygidum, the spine curving up at an angle of 45° in adult specimens and from 35° to 25° in the younger individuals; median lobe less convex than the lateral lobes and two-thirds as wide, uniformly rounded, and tapering gradually to the posterior extrem- ity; marked by 13 to 15 well-defined annulations and an elongate terminal ring; lateral lobes with 10 to 11 strongly defined ribs that curve in their outer half obliquely backward, terminating just within the narrow margin.
Surface of the glabella, thoracic segments, and pygidium punctate.
This is the largest trilobite yet discovered in the Devonian of the West. Individuals 35°" in length are indicated by the larger fragments, and one hypostoma is 7°" in length.
The pygidium resembles that of Dalmanites micrurus of the Lower Helderberg limestone of New York (Pal. N.Y., vol.iii, p.359, plate Ixxiv, figs. 13-20), but differs in the less number of annulations in the lobe and in the punctate surface. To D. anchiops Green (sp.) (Pal. N. Y., Hlustrations of Devonian Fossils, Crustacea, pl. ix) of the Upper Helderberg limestone of New York, it has a strong resemblance when compared to young individ- uals, but differences exist that readily separate the species.
The late Mr. F. B. Meek described and illustrated fragments of an unknown form of Dalmanites, from the Devonian limestone of the Pinon Range of Central Nevada, and the two pygidiz illustrated are closely related to those from the Eureka District, the character of the surface, which is smooth or granulose, as seen in badly weathered specimens, alone appear- ing to be different.
The specific name is given as a slight recognition of Mr. Meek’s ex- tended and valuable contributions to our knowledge of the invertebrate Paleontology of the Western United States.
Formation and locality—Lower horizon of the Devonian limestone, Comb’s Peak, and on the divide at the head of the Reese and Berry Camion, Eureka District, Nevada.
l4c0DWw
210 PALEONTOLOGY OF THE EUREKA DISTRICT.
Dalmanites (undt. sp.).
At Comb’s Peak a small and very perfect glabella of a species of Dal- manites was found. It is quite distinct from the associated Dalmanites Meek, as the surface is finely granulose with larger granules irregularly inter- spersed; the determination of its specific relations is left until more material
can be obtained.
Genus PROETUS Steininger. Proetus Haldemani Hill.
Proetus Haldemani Hall, 1861. Descriptions of New Species of Fossils, ete., p. 74. Haldemani Hall, 1862. Fifteenth Ann. Rep. N. Y. State Cab. Nat. Hist., p. 102. Haldemani Hall, 1876. Pal. N. Y., Illustrations of Devonian Fossils, Desc.
pl. xxi, figs. 7, S, 9.
Of this species the glabella and pygidium were alone obtained. The glabella varies from that of Proetus Haldemani in being more compressed and the pygidium in having one or two less annulations in the median lobe; otherwise they appear to be identical.
Formation and locality—Devonian limestone, Rescue Hill, west side of Rescue Canon, Eureka District, Nevada.
Proetus marginalis Conrad (Sp.).
Calymene marginalis (?) Conrad, 1839. Ann. Rep. Pal. N. Y., p. 66:
Proetus marginalis Hall, 1861. Descriptions of New Species of Fossils, etc., p. 76. marginalis Hall, 1862. Fifteenth Ann. Rep. N. Y. State Cab. Nat. Hist., p. 104. marginalis Hall, 1876. Pal. N. Y., Illustrations of Devonian Fossils, Crustacea,
pl. xxi, figs. 24-28.
We fail to discover, on a direct comparison of specimens of Proetus marginalis, trom the Tully limestone of New York and entire specimens from Comb’s Peak, any characters that would warrant the separation of the latter as a distinct species. The most prominent variation is in the width and outline of the border of the head, but on examining the figures given by Professor Hall, on plate xxi (Illustrations of Devonian Fossils), quite as wide a variation is shown between figs. 25 and 26 as between indi-
viduals from New York and Nevada. Continuing the comparison with
FOSSILS OF THE DEVONIAN. 211
New York specimens of the genus, P. clarus, Hall, of the same work, plate xx, fig. 12, is nearly identical with the Nevada form, its greater width and less convexity distinguishing it, also a slight difference in the details of the border of the head, features that in many species of the genera Caly- mene, Asaphus, etc., are not of specific importance unless very strongly marked.
Formation and locality—Lower horizon of the Devonian limestone; Comb’s Peak, Eureka District, Nevada.
Genus PHILLIPSIA Portlock. we Phillipsia coronata Hall? Phillipsia ? (Brachymetopus ?) ornata Hall, 1876. Pal. N. Y., Illustrations of Devonian Fossils, Crustacea, pl. xxi, fig. 1 (Nat. P. ornata Portlock 1843), coronata Hall, 1877. Cat. Amer. Pal. Foss., Miller, p. 221.
The central portion of the head is alone preserved in the specimen from Nevada; lateral compression has distorted its outline and convexity so that the comparison with the fragment from the Hamilton Group of New York, in which the glabella and frontal border is preserved, is neces- sarily imperfect, but from the close relations of the two, the species from Newark Mountain is for the present referred to Phillipsia coronata.
Formation and locality— Middle horizon of the Devonian limestone; Newark Mountain, Eureka District, Nevada.
SUPPOSED EGGS OF THE TRILOBITE.
Numerous small, spheroidal bodies, one-half a millimeter in diameter, occur in the Devonian limestone of Lone Mountain in association with the fragmentary remains of Phacops rana, Proetus marginalis, and Dalmanites Meeki. Inappearance they resemble the forms illustrated by M. Barrande,"* which he considers the eggs of the trilobite. A careful examination does not lead me to make any other reference of them, as they answer very closely to what I would conceive as the ova of the trilobite, and their
association with the remains of trilobites also favors this view.
4 Syst. Sil. Bohéme, p. 276, vol. i, Trilobites, pl. xxvii, figs. 1-3, ]p52.
FOSSILS OF THE CARBONIFEROUS.
A list of all the species known to occur in the Carboniferous formation of the Eureka District is given in the systematic catalogue at the end of this report, and only the rarer forms and new species are mentioned in the text. In some instances a species is partially identified by fragments, in which case the similarity to the described species is mentioned in the cat- alogue.
ECHINODERMATA.
Of this class, representatives of the Echinidea were obtained in the spines of two species, and of the Crinoidea in numerous segments of the columns of several species. As a whole the class is very imperfectly repre- sented in the central portions of the Rocky Mountain area, and with the ex- ception of a few species from Montana and New Mexico the great Crinoidal fauna of the Lower Carboniferous limestones of the Mississippi Valley is unknown in the Rocky Mountains. A further examination of the Lake Valley District in New Mexico, however, will undoubtedly add largely to the knowledge of the distribution of the Crinoidal fauna, as several species from there are identical with those from the Burlington limestone.
Since the above was written Mr. F. Springer (Amer. Jour. Sci., vol. xxvii, p. 97, 1883), has described a large and varied fauna from the Lake Valley District.
Genus ARCHASOCIDARIS McCoy. Archeocidaris, sp.?
Two species are represented by the spines. One is very much like A. Wortheni Hall (Geol. Surv. Iowa, vol. i, pt. 2, p. 700, 1858), and the other
212
FOSSILS OF THE CARBONIFEROUS. 213
approaches A. Shumardana Hall (Ibid., p. 699) of the Lower Carboniferous limestone.
Formation and locality—Lower portion of the Lower Carboniferous limestone on east slope of a small conical hill on the east side of Secret- canon-road Canon, Eureka District, Nevada.
BRACHIOPODA.
Genus DISCINA Lamarck. Discina Newberryi Hall. Plate xviii, figs. 3 (2, 2.a?).
Discina newberryi Hall, 1863. Sixteenth Ann. Rep. N. Y. State Cab. Nat. Hist., p. 30. Pal. N. Y., 1867, vol. iv, p. 25, pl. i, figs. 10a, b, 11a-e. Discina (Orbiculoidea) Newberryi Meek, 1875. Pal. Ohio, vol. ii, p. 277, pl. xiv, figs. 1a-d.
The Eureka shells present no features by which they can be distin- guished from this species when directly compared with authentic specimens from the Waverly sandstones of Ohio.
At a little lower horizon a form of Discina occurs in a black shale that may belong to this species. All the specimens are more or less distorted by pressure. The two valves are shown by figs. 2, 2a of plate xviii.
Formation and localities—Lower portion of the Carboniferous Group, Richmond Mountain and on east slope of a small conical hill on the east side of Secret-cation-road Canon, Eureka District, Nevada.
Discina nitida Phillips. Plate vii, figs. 4, 4a. Orbicula nitida Phillips, 1836. Geol. of Yorkshire, pt. 2, p. 221, pl. xi, figs. 10-13. Discina Missouriensis Shumard, 1860. Trans. St. Louis Acad. Sci., vol. i, p. 221 (as deter- mined by Meek). nitida Meek & Worthen, 1873. Geol. Surv. IIL, vol. v, p. 572, pl. xxv, fig. 1. For description and synonomy, see Mon. Brit. Foss. Brach. Davidson, vol. Leal oie Well-marked examples of this species occur in the Lower Carbonifer- ous limestone of Coal Hill, in the Pancake Range, and also on the west side
214 PALEONTOLOGY OF THE EUREKA DISTRICT.
of Mokomoke Ridge, White Pine Mining District, Nevada. This horizon is nearly equivalent to that in the Eureka District, where D. Newberryi is so abundant.
Discina connata, 0. sp. Plate vii, figs. 3, 3a.
Shell subcircular, a little more expanded in front than on the posterior portion.
The larger or upper valve is depressed conical with the apex below the greatest elevation of the shell and near to or on a line with the posterior margin.
Surface marked by concentric strize and very delicate radiating lines, the latter showing more prominently on the interior of the shell.
The only interior markings shown are two long, slender, slightly ele- vated median ridges with a shallow depression between them.
Dimensions: width, 3™; elevation of upper valve, 8™™. ‘There are two specimens of the upper valve of this fine Discina in the collection, both of - which have the apex nearly over the posterior margin. It may be that it is only a variety of Discina nitida, but with our present knowledge of the two forms a specific name is given to it.
Formation and locality—Lower portion of Lower Carboniferous lime- stone in cafion directly south of a small conical hill on the east side of Secret-canon-road Canon, Eureka District, Nevada.
Genus PRODUCTUS Sowerby.
Productus subaculeatus Murch. Plate vii, fig. 2. Synonomy: See descriptions of Devonian Brachiopods, ante, p. 128.
A direct comparison with the Upper Devonian specimens of this species shows that the Lower Carboniferous specimens are identical, although a belt of conglomerate 3,000 feet in thickness separates them in the geologic section.
FOSSILS OF THE CARBONIFEROUS. 215
The Carboniferous form is associated with Productus Cora, P. semire- ticulatus, P. muricatus, P. elegans, Spirifera Rockymontana, S. camerata, ete.
Formation and locality—Lower portion of Lower Carboniferous lime- stone, in canon directly south of a small conical hill on east side of Secret- canon-road Canon, Eureka District, Nevada.
Genus SPIRIFERA Sowerby.
Spirifera trigonalis Martin (Sp.). Plate xviii, fig. 11. Conchyliolites anomites trigonalis Martin, 1809. Pet. Derb., tab. xxxvi, fig. 1. Spirifer trigonalis Sowerby, 1820. Min. Con., tab. 265, fig. 1 (not 2 and 3). Spirifera trigonalis, var. 2, McCoy, 1855. Brit. Pal. Foss., p. 423. trigonalis Davidson, 1858. Brit. Carb. Brachiopoda, p. 29, pl. v, figs. 25- 34; 35-372 bisuleata Davidson, 1861. Ibid. Mr. Davidson gives the synonomy up to the date of his publication, 1858, also that of Spirifera crassa De Koninek, Spiri- Sera grandicostata, and S. transiens McCoy, which he regards as forms of this widely varying species. Spirifer increbescens Hall, 1858. Geol. Surv. Towa, vol. i, pt. 2, p. 706, pl. xxvii, figs. 6a-i.
After a most careful study of a large series of specimens of this species, Mr. Davidson has united all the forms previously placed under the species mentioned in the list of synonyms as variations of a single very variable species and, in speaking of the winged, simple form and the transversely oval, rounded, thickened variety crassa, says: “The notion of both being the modification of a single species will, to the generality of observers, appear absurd ; still if we find every variation connecting these extremes, are we to refuse the evidence of our eyes and senses, and to create as many species as we possess specimens?” An examination of Mr. Davidson’s beauti- ful illustrations cannot fail to convince one of the specific relationship of the different forms, and I have no doubt that the Nevada shell before me is one of the varieties of this widely-distributed species.
In the Mississippi Valley it is found in the Chester limestone of the Lower Carboniferous formation of the State of Illinois, and described by Professor Hall as Spirifera increbescens. Mr. Davidson states that it is abundant in England, Ireland, and Scotland, and that on the Continent it js found in Belgium.
216 PALEONTOLOGY OF THE EUREKA DISTRICT.
Formation and localities —Lower portion of the Carboniferous Group, summit of Diamond Peak, and in the low hills at the mouth of Hayes’ Canon, Eureka District, Nevada.
Spirifera Leidyi N. and P.
Plate xviii, figs. 4, 4a.
Spirifera Leidyi, Norwood & Pratten, 1855. Jour. Acad. Nat. Sci. Philad., 2d series, vol. iii, p. 72, pl. ix, figs. 2 a—c.
Spirifera bifurcatus, Hall, 1857. Trans. Albany Institute, vol. iv, p. 8.
Spirifera bifurcata, Whitfield, 1882. Bull. Amer. Mus. Nat. Hist., vol. i, No. 3, p. 47, pl. vi, figs. 13-15. In the remarks accompanying the Jatter reference, Mr. Whitfield considers S. bifurcata as a synonym of S. Leidyi.
The only mention of the occurrence of this species west of the Missis- sippi basin is found in a list of Carboniferous fossils from the Oquirrh Range, Utah, given in the second volume of the Geological Exploration of the For- tieth Parallel, page 447.
There appears to be little doubt of the specific identity of the Nevada shell with that from the typical locality in the Chester limestone of Illinois.
Formation and localities—Lower portion of the Carboniferous Group, Richmond Mountain, and on the low hills south of the mouth of Hayes’ Canon, Eureka District, Nevada.
Spirifera annectans, n. sp. Plate xviii, figs. 7,7 a.
Shell below the medium size, somewhat inflated, length and breadth as 3 to 4, respectively ; anterior and lateral margins forming rather more than a semicircle before uniting with the cardinal line, which is about three-fifths the breadth of the shell.
Ventral valve with a strongly defined mesial sinus extending to the extremity of the rather prominent, incurved beak; the bottom of the sinus is but slightly rounded and with a scarcely perceptible elevated line along the center; the sinus is bordered by a rounded rib, outside of which, on each side, there are four ribs, the outer almost obsolete on the smooth
FOSSILS OF THE CARBONIFEROUS. Zig,
upper lateral slopes of the valve; area beneath the beak unknown, as it is concealed by the adhering matrix. Dorgal valve nearly as convex as the ventral ; beak small, incurved, and projecting a little over the hinge margin; mesial lobe elevated, about as broad as the sinus of the opposite valve and with a slight median groove; lateral ribs, four on each side.
Surface of valves marked by fine concentric lines of growth.
This species is allied to S. Leidyi, but differs in the less number of ribs on the valves, and also in the rounded lateral angles.
Formation and locality.—Lower portion of the Carboniferous Group, Richmond Mountain, Eureka District, Nevada.
Spirifera neglecta Hall. Plate xviii, fig. 10. Spirifer neglectus Hall, 1858. Geol. Surv. Iowa, vol. i, pt. 2, p. 643, pl. xx, fig. 5. neglectus Worthen & Meek, 1875. Geol. Surv. Ilinois, vol. vi, p. 523, pl. xxx, figs. Le, 2a.
This large and strongly-marked species of the Keokuk limestone of the Lower Carboniferous of Iowa and Illinois, is represented by single valves and one medium-sized entire shell. There appears to be a strong specific identity between the Nevada specimens and those from the Mississippi Valley.
Formation and localities—Lower portion of the Carboniferous Group, Richmond Mountain, and on the east slope of a small conical hill on the east side of Secret-canon-road Canon, Eureka District, Nevada.
Spirifera desiderata, un. sp.
Plate vii, fig. 8.
Dorsal valve subsemicircular in outline, extremities submucronate, moderately convex; mesial fold not very prominent and flattened across the top, well defined at the margins, and with a slightly depressed median line.
Surface marked by about thirty simple rounded plications, which are of moderate strength and little elevated ; a few concentric lines are shown, but
218 PALEONTOLOGY OF THE EUREKA DISTRICT.
the exfoliation of the shell has destroyed any finer striz that may have existed.
This is essentially a Devonian type, approaching such forms as Spiri- fera Marcyi, S. macronata (Pal. N. Y., vol. iv), in their dorsal valves; unfor- tunately there are no specimens of the ventral valve in the collections.
Formation and locality.—Lower portion of the Lower Carboniferous limestone in canon directly south of a small conical hill on east side of Secret-canon-road Cation, Eureka District, Nevada.
Subgenus SPIRIFERINA D’Orbigny. Spiriferina cristata Schlotheim. Plate xviii, figs. 12, 13.
Terebratulites cristatus Schlotheim, 1816. Beitr. z. Naturg. d. verst. in Akademie der Weissenschaften zu Miinchen, pl. i, fig. 3. Spirifera octoplicatus Sowerby, 1827. Min. Con., p. 120, pl. 562, tables 2, 4, 4. Spirifer cctoplicata? Hall, 1852. Stansbury’s Expd. Great Salt Lake, p. 409, pl. iv, figs. 4a, b. (Not S. octoplicatus Sowerby.) Kentuckensis Shumard, 1855. Geol. Surv. Missouri, vol. i, pt. 2, p. 208. Kentuckensis Hall, 1856. Pacific Railroad Rep., vol. iii, p. 102, pl. ii; figs. 10, 11. spinosus Norwood & Pratten, 1855. Jour. Acad. Nat. Sci. Philad., vol. iii, p. 71, pl. ix, figs. la-d. spinosus Hall, 1858. Geol. Surv. Iowa, vol. i, pt. 2, p. 706, pl. xxvii, figs. 5a-c. Spiriferina octoplicata Davidson, 1852. Quart. Jour. Geol. Soe, London, vol. xviii, p. 29, pl. i, figs. 12-13: ~ Spirifera Kentuckensis var. propatulus Shumard, 1866. Trans. St. Louis Acad. Sci., vol. ii, p. 409. laminosus Geinitz, 1866. Carb. und Dyas in Nebraska, p. 45. (Not S. lami- nosus McCoy.) Spiriferina Kentuckensis Meek, 1872. U.S. Geol. Surv. Nebraska, p. 189, pl. vi, figs. 3a-d; pl. viii, figs. 11a, b. spinosa ? Derby, 1874. Bull. Cornell University, vol. i, pt. 2, p. 23, pl. vi, figs. 8, 13, 14. Kentuckensis White, 1875. Expl. and Surv. West 100th Meridian, vol. iv, pt. 1, p. 138, pl. x, figs. 4a—c.
Characteristic specimens of this species occur in the lower and central portions of the Carboniferous rocks of the district, and in the upper strata they are associated with a form that is typical of S. spinosa, of the Chester limestone of Illinois. This same association also occurs at Coal Hill, in the
FOSSILS OF THE CARBONIFEROUS. 219
Pancake Range, where numerous examples occur that may be referred to either form, according as the spine bases are more or less prominent, or the shell contracted or extended laterally. On comparing these and specimens of each variety from the Mississippi Valley it seems impossible to avoid the conclusion that they are one and the same species.
Fig 12, plate xviii, is taken from a Chester limestone specimen, and the adjoining fig. 13 from a specimen found in the Upper Carboniferous limestone of the Eureka District. Comparing these and also the specimens with Mr. Davidson’s figures of Spiriferina cristata Schloth., 1816—S. octo- plicatus Sowerby, 1827, it appears that we have another very variable spe- cies that has a great vertical range and an extended geographic distribu- tion. Dr. White (Expl. and Surv. West 100th Merid., vol. iv, pt. 1, p. 140, 1875) regards Spiriferina Kentuckensis and S. octoplicata as distinct species, but with the evidence now accessible I should be inclined to consider them and also S. spinosa as varieties of one and the same species
In the Devonian White Pine shale of the White Pine Mining District there is a form that in its plications is similar to S. cristata, and in surface markings it is very much like S. insculpta Phillips. It occurs at the summit of the Devonian, and is referred to S. cristata Mr. Davidson has recognized the species in both the Middle and Lower Devonian (British Devonian Brachiopoda, p. 123).
Formation and localities —In the Lower Carboniferous on the east slope of a small conical hill on the east side of Secret-cafion-road Canon and in the Upper Carboniferous limestone of the western slope and foothills of Diamond Peak, Eureka District, Nevada.
Genus SYRINGOTHYRIS Winchell. Syringothyris cuspidata Martin (Sp.).
Anomites cuspidatus Martin, 1796. See Davidson’s Mon. Brit. Carb.Brach., p. 44, and supplement, vol. iv, p. 278, 1880. Spirifer cuspidatus? Meek, 1877. Geol. Expl. Fortieth Par., vol. iv, p. 87, pl. iii, figs. 11, lla. Mr. Meek cites this species from above the Devonian of the White Pine
Mountains, Nevada. It is quite abundant on Richmond Mountain in one
220 PALEONTOLOGY OF THE EUREKA DISTRICT.
stratum, in association with Spirifera neglecta and other Lower Carboniferous fossils, Eureka District, Nevada.
Specimens of S. cuspidatus have recently been received (1884) from the Lower Carboniferous limestone in the Little Belt range of mountains ‘hear Clendenin, Montana.
Genus RETZIA King. Retzia radialis Phillips (Sp.). Plate vii, figs. 5, 5a-h.
Terebratula radialis Phillips, 1836. Geol. Yorkshire, vol. ii, p. 223, pl. xii, figs. 40, 41. mantiwe De Koninck, 1843. Anm. Foss., p. 287, pl. xix, figs. 4a-d. (Not T. mantie of Sowerby.) Atrypa radialis McCoy, 1844. Syn. Carb. Foss. Ireland, p. 156. Terebratula radialis De V. & De K., 1845. Russia and the Ural Mountains, vol. ii, p. 89, pl. x, figs. 9a, b. Retzia radialis Morris, 1854. Cat. Brit. Foss., p. 145. Spirigerina ? radialis McCoy, 1855. Brit. Pal. Foss., p. 438. Terebratula Mormoni Marcou. Geol. North America, p. 51, pl. vi, figs. 11a-c. Retzia punctilifera Shumard, 1858. Trans. St. Louis Acad. Sci., vol. i, p. 220. Mormoni Meek & Hayden, 1859. Proc. Acad. Nat. Sci. Philad., vol. xi, p. 27; Geinitz, 1864. Carb. und Dyas in Neb., p. 39, tab. iii, fig. 6. subglobosa McChesney, 1860. Descriptions New Pal. Fossils, p. 45, and pl. i, fig. 1. Illustrations of same, 1865. radialis Davidson, 1861. Mon. Brit. Carb. Brachiopoda, pp. 87, 218, pl. xvii, figs. 19-21; pl. li, figs. 4-9. radialis Phillips, (sp.), var. grandicosta Davidson, 1861. Carb. Brach. Coll. in India, Quart. Jour. Geol. Soe., vol. xviii, p. 28, pl. 1, fig. 5. compressa Meek, 1864. Geol. Surv. California, Pal., vol. i, p. 14, figs. 7a-e. Kayser, 1882. Richthofen, China, vol. iv, p. 176, tab. xxii, figs. 1-4. punctulifera McChesney, 1867. Trans. Chicago Acad. Sci., vol. i, ‘p. 32, pl. i, fig. 1. punctulifera Meek, 1872. U.S. Geol. Surv. Nebraska, p. 181, pl. i, fig. 13, pl. v, fig. 8. Mormoni White, 1875. Expl. and Sury. West 100th Merid., vol. iv, pt. 1, p. 141, pl. x, figs. 7 a-c. Compare Retzia Marcyi Shumard, 1854, Expl. Red River of Louisiana, p. 190, pt. 1, fig. 4a, b; also, Retzia Verneuiliana and R. vera Hall, Geol. Surv. Iowa, vol. i, pt. 2, pp. 657, 704, 1858.
On bringing together a series of specimens of this species from Ne- vada and New Mexico it became at once apparent that it was very
FOSSILS OF THE CARBONIFEROUS. 221
variable, and also specifically identical with the widely distributed R. radi- ais. All the specimens agree in general form, the presence of a small area and a vertically ribbed, punctate shell. In the number and strength of the radiating costa, however, the greatest difference is shown. I now have before me specimens with 7, 10, 12, 13, 17, 22, and 25 costee on each valve. With the two extremes to base a separation on both Retzia Mormoni Marcou, and R. radialis, var. grandicosta Davidson, appear as good species— one characterized by a few angular radiating ribs, and the other by numer- ous rounded radiating ribs. With the intermediate links to connect the shell with seven ribs and that of twenty-five and, also, any variations of form that occur among many examples, we are necessitated to unite all under one species, and to refer it to Retzia radialis of Phillips, as Davidson has shown that that species has the same range of variation in the number and character of the radiating ribs, and a comparison of the American specimens with his figures and descriptions leaves little, if any, doubt of the specific identity of the two.
In the White Pine shales of the Upper Devonian of the White Pine Mining District, Nevada, a shell occurs that is identical with the more finely- ribbed examples from the Lower Carboniferous limestone of the Pancake Mountains (situated between White Pine and Eureka) and those occurring at relatively the same horizon near Santa Fé, New Mexico.
As far as our observations go, the finely-ribbed variety appears first in the Upper Devonian, and the more coarsely ribbed in the Middle Carbon- iferous in association with the intermediate forms, uniting them with the finely-ribbed variety.
The coarsely-ribbed variety described by Davidson, from the Punjab, India, is represented by the Nevada shell bearing seven plications, and the more finely-ribbed form from Russia is the usual variety from England, Belgium, and America.
Dr. Kayser has placed the specimens representing the species in China under £. compressa Meek, a variety of R. radialis Phillips. All the differ- ences mentioned by Meek as characterizing R. compressa, as distinct from R. punctulifera, are shown in a good series of R. radialis.
222 PALEONTOLOGY OF THE EUREKA DISTRICT.
Retzia Marcyi Shumard is probably a finely-ribbed variety of R. radialis, and a large series of specimens may bring R. vera and R. Verneuiliana of the Lower Carboniferous limestone of Iowa into the same group as varieties.
As now known in Central Nevada, R. radialis ranges from the Upper Devonian through the Lower into the Upper Carboniferous limestone, a horizon equivalent to that of the Upper Coal Measures, where it is found in Nebraska, Illinois, ete. Its great geographic range has already been noticed in speaking of its occurrence in China, India, the Ural Mountains, England, and Western America.
Genus ATHYRIS McCoy.
Athyris hirsuta Hall. Plate xviii, fig. 5.
Spirigera (Athyris) hirsuta Hall 1857." Trans. Albany Institute, vol. iv, p. 8. Athyris sublamellosa Hall, 1858. Geol. Surv. Iowa, vol. i, pt. 2, p. 702, pl. xxvii, fig. la-c. Idem., Derby, 1874. Bull. Cornell University, vol. i, No. 2, p. 10, pl. ii, figs. 9-12; pl. ili, figs. 15, 21, 29; pl. vi, fig. 16; pl. ix, figs. 5, 6. Athyris hirsuta Whitfield, 1882. Bull. Amer. Mus. Nat. Hist., vol. i, p. 49, pl. vi, figs. 18-21. Compare Athyris Royssit. See Brit. Foss. Brach. Davidson, vol. ii, p. 84. There is so little difference between the examples of this species from Nevada and those from the Chester limestone of Illinois, that the lithologie features of the matrix alone distinguishes them. It is not improbable that this species is founded on a small variety of Athyris Royssii, and Mr. Meek has placed it as a doubtful synonym (Geol. Expl. Fortieth Par., vol. iv, p. 82). Formation and locality—Lower portion of the Carboniferous Group, Diamond Peak, in the Eureka District, and at Coal Hill, Pancake Range, Nevada.
1sThe paper describing the Spergen Hill fossils was printed and copies distributed in 1857 in advance of the publication of Volume IV of the Albany Institute Transactions, which bears date 1858-1864,
FOSSILS OF THE CARBONIFEROUS. 223
Genus RHYNCHONELLA Fischer. Rhynchonella Eurekensis, n.§sp.
Plate xviii, figs. 8, 8da-c.
Shell below the average size; somewhat trigonal in outline; the width and height subequal, or the latter a little greater than the former; dorsal valve a trifle deeper than the ventral.
Ventral valve with a prominent beak and strongly marked but not deep mesial sinus that is about one-half the width of the shell at the front margin; sides sloping gradually away from the edges of the sinus and more abruptly from the somewhat elevated upper portion. Dorsal valve much more convex than the ventral and marked by a slight, broad mesial fold on the lower portion; beak strongly incurved; general surface rounding to the margins from the central portions of the valve.
Surface of the valves marked by from 40 to 50 round, simple plications.
This species is distinguished from any described by its general form and the numerous radiating plications.
Formation and localities—Lower portion of the Carboniferous Group, east slope of a small conical hill on the east side of Secret-canon-road Canon, and on the northeast side of the cation north of Pinto Peak, Eureka District, Nevada.
Rhynchonella Thera, u. sp. Plate vii, figs. 6, 6a-c.
Shell small, subglobose or suboval, strongly convex, with a prominent mesial elevation and suture.
Ventral valve a little less convex than the dorsal, the greatest con- vexity being on the posterior half; below the middle a broad, not very sharply defined sinus begins, which becomes deeper and expands towards the front; beak imperforate and slightly curved over that of the opposite valve.
Dorsal valve most convex at the middle; the median fold is not usu- ally strongly defined; it has a slight central sinus that reaches from near the beak out to the front termination of the fold, the latter starting about
the center of the shell. Surface marked by fine concentric lines of growth.
224 PALEONTOLOGY OF THE EUREKA DISTRICT.
This species is related by its form to Athyris ? polita Hall (Pal. N.Y, vol. iv, p. 293), of the Chemung Group of New York, and also in some of the specimens to Athyris trinuclea (see Bull. Amer. Mus. Nat. Hist., vol. i, p. 50), of the Lower Carboniferous of Indiana, ete.; the beak of the ventral valve, however, appears to be imperforate.
Formation and locality—lLower portion of Lower Carboniferous lime- stone in canon directly south of Conical Hill, on east side of Secret-carion- road Canon, Eureka District, Nevada.
Genus CAMAROPHORIA King.
Camarophoria Cooperensis Shumard ? Plate xviii, fig. 6.
Rhynchonella Cooperensis Shumard, 1855. Geol. Surv. Missouri, pt. 2, p. 204, pl. C, 4a-d.
With the exception of having fewer plications, the Eureka specimens agree in all essential features with those from the Chouteau limestone of Missouri, as described by Dr. Shumard. A comparison of specimens may show the western form to be a distinct species, but the means of comparison at present available leads to referring them as above.
Formation and localities—Lower portion of the Carboniferous Group, on the western slope of Richmond Mountain, and in limestone capping Diamond Peak, Eureka District, Nevada.
Genus TEREBRATULA Llhwyd.
Terebratula hastata Sowerby.
Synonymy: See Mon. Brit. Foss. Brach. Davidson, vol. ii, p. 11.
With a number of specimens to compare with Mr. Davidson’s beauti- ful figures of this species we cannot find reasons for a specific separation of the American form from that of Europe. Some of the Eureka shells are a little more expanded in front, but scarcely more so than examples figured by Mr. Davidson.
Formation and locality—Lower portion of Lower Carboniferous lime- stone in canon directly south of a small conical hill, on east side of Secret- canon-road Canon, Eureka District, Nevada.
FOSSILS OF THE CARBONIFEROUS. 220
LAMELLIBRANCHIATA.
The occurrence of a number of species of this class in the Carbonifer- ous Group, in the region of the Rocky Mountains, is unusual, as heretofore it has been but sparingly represented.
In 1852 Prof. J. Hall (Stansbury’s Expedition to the Great Salt Lake, p- 412) described a few species, viz: Avicula=Pseudomonotis curta, Tellino- mya protensa (probably belongs to the genus Modiomorpha), Allorisma terminalis, Cypricardia occidentalis, Nucula arata.
Of these the last three species were obtained from Eastern Nebraska or the Mississippi Valley region. To the first two may be added twenty-two species mentioned by different authors:
Marcou, J., 1858. Geology of North America, p. 44. Myalina Apachesi.
Meek, F. B., 1860. Preliminary Notice. 1876. Report Explorations Across the Great Basin of Utah, Simpson, p. 354. Aviculopecten Utahensis.
White, C. A., 1874. Preliminary Notice. 1875. Explorations and Surveys West of the 100th Meridian, vol. iv, pt.1, p.146. Aviculopecten occidentalis, A. Corey- anus, A. McCoyi, A. ? interlineatus, Pinna peracuta?, Monopteria Marian, My- alina, sp., M. ? Swallovi, Bakevellia parva, Schizodus Wheeleri, Allorisma subcuneata, var. Also, in Appendix to Supplement of vol. iii of the same Survey, 1881, p.xxv. Myalina Permiana and Pleurophorus subcostatus.
Whitfield, R. P., 1875. Carroll, Montana, to Yellowstone National Park, Ludlow, p. 143. Pinna Ludlovi.
Meek, F. B., 1877. Geological Exploration of the Fortieth Parallel, vol. iv, p.96. A. occidaneus.
Two other species are described as from the Carboniferous, but they are more properly referred to the Devonian by Messrs. Hall and Whitfield. Hall, J.,and Whitfield, R. P.,1877. Geological Exploration of the Fortieth Parallel, vol.
iv, p. 273. Aviculopecten Weberensis, A. curto-cardinalis, A. parvulus, Mya- lina aviculoides, M. Permiana, Sedgwickia ? concava, Cardiomorpha Missou- riensis.
The latter species, Cardiomorpha Missouriensis, although described from the Coal Measures of Missouri and Illinois, is, in Nevada, found in the strata at the summit of the Devonian and is not, there, a Carboniferous species; with this exception, all of the twenty-four species heretofore described are from the upper portions of the Carboniferous Group, usually referred by
authors to the Coal Measures. From the latter horizon but one species is 15 cD W
226 PALEONTOLOGY OF THE EUREKA DISTRICT.
added, Macrodon tenuistriata; all the others from the Eureka District occur in the lower portion of the Lower Carboniferous limestone. The relations of the greater number of the species are with Devonian and Lower Carbon- iferous species rather than with those of the Coal Measure Groups of the Mississippi Valley.
Two species, Macrodon Hamiltone and Grammysia arcuata, belong to the Middle Devonian in New York, and Grammysia Hannibalensis and Sangui- nolites AZolus occur in the Chemung and Waverly Groups.
Larger collections from the localities already known in the Eureka District’ will undoubtedly add materially to the number of species, if not genera, already described, as many fragments of unidentified forms occur in the collection; but with twenty-one genera, represented by forty-five species, to add to those already mentioned by the above authors, the Lamelli- branchiata is fairly represented in the Carboniferous system of Nevada.
a“
Genus AVICULOPECTEN McCoy. Aviculopecten Haguei, n. sp.
Plate xix, fig. 4.
Shell large, oval or suborbicular in outline, exclusive of the ears; left valve depressed convex, hinge-line about three-fourths of the greatest width below; umbonal margins converging to the beak at an angle of 90°; lateral margins rounding into the regularly curved pallial margin; pos- terior ear larger than the anterior, less obtuse, and not so distinctly defined by the angle of the umbonal slope; the sinuses separating the ears from the lateral margins are shallow, the posterior being more broadly rounded than the anterior.
Surface of each ear ornamented by fine concentric striw, and that of the posterior by 5 or 6 narrow, radiating coste; in addition, the body of of the valve is marked by numerous rounded radiating costz, that, towards the pallial margin, become subangular, with a quite broad interspace between them; the concentric strize that are so marked on the ears are scarcely dis- cernible except on the outer portions of the shell, owing to the imperfect state of preservation of the outer surface.
FOSSILS OF THE CARBONIFEROUS. 221
Dimensions : height, 9.5™; width, 8°"; convexity of left valve, 1.25°™.
This is an unusually large and strongly marked species, and unlike any described from this horizon.
Formation and locality—Lower portion of the Carboniferous Group, east side of Secret-canon-road Canon, on the east slope of a small conical hill, Eureka District, Nevada.
Aviculopecten Eurekensis, n. sp. Plate xix, figs. 2,3.
General outline exclusive of the ears subovate, varying somewhat in different specimens. General surface moderately convex when not acci- dentally compressed ; ears subequal in size, the posterior being the larger, the anterior shorter and more obtuse. Hinge-line less than the greatest width of the shell. Beak small, obtusely pointed.
Surface marked by from 18 to 25 simple lines or radiating costz, that are crossed by fine concentric strie. Left valve unknown. The hinge is smooth each side of the beak.
Dimensions : height of narrow form, 4°; of broad form, 3.5™; width, 3.5°™ and 4°™; convexity of left valves, 1™ and 0.75™, respectively.
This species is allied to A. Haguei, but differs in having about one-half the number of radiating surface costae.
Formation and locality—Lower portion of the Carboniferous Group, on the east slope of a small conical hill on the east side of Secret-cafion-road Canon, Eureka District, Nevada.
Aviculopecten peroccidens, n. sp. Plate viii, fig. 8.
General outline, exclusive of the ears, suborbicular to subovate in the more elongate specimens. General surface rather strongly convex when not flattened by accidental compression. Anterior ear considerably smaller than the posterior. Hinge-line less than the greatest width of the shell below. Beak subcentral. Angle of divergence of the body of the shell from the beak, within the ears, 110°.
228 PALEONTOLOGY OF THE EUREKA DISTRICT.
Surface marked by from 25 to 30 simple radiating cost, the inter- spaces wider than the cost, and with intercalated smaller cost rising in some of them; concentric strize and lines of growth are more or less dis- tinctly shown. Right valve unknown.
The interior of the hinge unknown.
Dimensions: height and width of average size specimen, 3.5™; con- vexity of left valve, .75°™.
This species shows considerable similarity to A. Eurekensis. It differs in the presence of a larger number of costz and in its more orbicular form.
Formation and locality—Lower portion of Lower Carboniferous lime- stone in canon directly south of a conical hill on east side of Secret-cafion- road Canon, Eureka District, Nevada.
Aviculopecten Pintdensis, n. sp. Plate viii, fig. 6.
Shell small, rounded ovate in outline exclusive of the wings. Left valve gently convex. Hinge-line about two-thirds as long as the greatest. width of the shell below. Ears subequal in size, the anterior with a some- what more deeply cut, rounded sinus beneath. Beak small, obtusely pointed and scarcely extending beyond the cardinal margin.
Surface marked by numerous fine radiating linear cost, twenty in a distance of five millimeters, with a few finer strize or coste in some of the interspaces; the coste are present on the ears and are strongly defined on the anterior ear; a few concentric lines of growth appear on the posterior ear and extend on to the disk of the shell as rather indefinite undulations or lines of growth.
Interior characters unknown.
Dimensions: height, 2; width, 2°; convexity of left valve, 2™.
This pretty little shell is of the type of Aviculopecten Coxanus M. and W. (Geol. Surv. Ill, vol. ii, plate xxvi, fig. 6a, b), differing only in its more erect form and shorter ears. In form it also approaches A, (Pecten) plicatus Sowerby, as figured by De Koninck (Anm. Foss., plate iv, fig. 6).
Formation and locality—Lower portion of Carboniferous Group, in canon north of Pinto Peak, Eureka District, Nevada.
FOSSILS OF THE CARBONIFEROUS. 229
Aviculopecten affinis, n. sp.
Plate xix, figs. 1, la.
Shell of medium size. Left valve, exclusive of the ears, suborbicular in outline, depressed convex; hinge-line varying from two-thirds to five- sixths of the greatest width below; posterior margin most prominent at the transverse center of the shell from where it curves gently and nearly per- pendicularly downward to the somewhat abruptly rounded basal margin, and upward to the sinus beneath the ear; anterior margin most prominent above the center, from which it curves nearly as the opposite margin to the base, and above, more abruptly; ears subequal, subtriangular in form, and defined by a sinus that varies in depth and shape on different shells; beak subcentral, pointed, and extending above the hinge-line.
Surface of both ears and the body of the valve ornamented with num- erous fine radiating coste, every third or fourth one of which is raised above the intervening costee, the latter usually running out before reaching the umbo; fine concentric strize cross the radiating striz on the ears and body of the valve, being more strongly marked on the anterior ear.
Right valve nearly flat, with a stronger sinus under the anterior ear, and the surface marked by numerous simple radiating striz and concentric striz on the ears.
An examination of many specimens in all conditions of preservation fails to show any crenulations on the hinge margin, although the interior is well preserved in several examples.
This species varies considerably in the outline of the valves; some are longer than wide and others with length and width subequal In the latter case the left valve is somewhat like that of Crenipecten Winchelli Meek, of the Waverly Group of Ohio. (See Pal. N. Y., vol. v, pt. 1, plate ix, figs. 1, 2, 4, 25-30.) The right valve, however, is finely but strongly striate longitudinally, while that of C. Winchelli is nearly smooth, except on the ears.
This is a very abundant species in two localities, almost filling some of the layers on the little conical hill on the east side of Secret-cation-road Cation, where it is associated with A. Haguei, A. peroccidens, and A. Eurekensis.
230 PALEONTOLOGY OF THE EUREKA DISTRICT.
Formation and localities—Lower portion of the Carboniferous Group with the preceding, and also on the west slope of Richmond Mountain, Eureka District, Nevada.
Aviculopecten, sp.?
Two other species of the genus are shown by rather large-sized shells, but their condition is such that the specific determination would be uncer- tain, and with the genus so well represented they are left for more material and future study to determine their specific relations.
Genus STREBLOPTERIA McCoy.
Streblopteria similis, n. sp. Plate viii, figs. 4, 4a-d, and plate xix, fig. 7.
Shell’ of medium size; outline, exclusive of the anterior ear, ovate; general surface depressed convex. The two valves are very much alike in convexity and form, except at the anterior ear and the slope beneath; the right valve has a deep,'sharply-cut byssal sinus beneath the ear, the ear joining the body of the shell higher up towards the beak. The posterior ear is either very short and small, or obsolete, being merged into the flat- tened posterior umbonal slope. Hinge-line very short. Beaks small, the sides sloping away at an angle of about 80°.
Surface of the larger shells smooth or with fine concentric striz and lines of growth; a few very indistinct fine radii are present towards the lower ‘margin; the anterior ear of the right valve is marked by concentric lines of growth and rather strong radiating coste; on the left valve the anterior ear has only the concentric striz. On all the smaller shells the raised ra- diating striz or fine costz are present in varying degrees of distinctness up to well-marked striated forms that in surface characters apparently have no specific relation to the large, smooth shells
Dimensions: height of two examples, 3.75™ and 1.75"; breadth, 3.25 and 1.5°%™; convexity of larger, 4""; of smaller, about 2™™.
The peculiar obliquity of the valves, the deeply-cut sinus beneath the anterior ear of the right valve, and the smooth surface relates this species
FOSSILS OF THE CARBONIFEROUS. Zo
to Streblopteria laevigata McCoy (Brit. Pal. Foss., p. 482), the type of the genus. The form is also that of species referred to the genus Pernopecten, but in a large number of examples I have not been able to find the crenu- lated hinge area characteristic of that genus; the species agrees more closely with Streblopteria in other characters. The smaller shells resemble Pecten ? pusillus of the Permian (see Mon. Perm. Foss., England, p. 153), but differ in having a longitudinally striated surface.
Streblopteria tenuilineatus M. and W. (Geol. Surv. Ill, vol. ii, plate xxvi, fig. 9a) is the only American species that has been referred to the genus. It differs very materially in form and surface characters from the species under consideration.
Formation and localities —Lower portion of the Carboniferous Group in the canon north of Pinto Peak; on the west slope of Richmond Mountain, and in the canon south of a small conical hill on the east side of Secret- canon-road Canon, Eureka District, Nevada.
Genus CRENIPECTEN Hall.
The genus Crenipecten is described by its author as ‘Like Aviculopec- ten in form, hinge furnished with a series of small cartilage pits throughout its entire length.” Example, Crenipecten Leon and C. crenulatus (Pal. N. Y., vol. v, pt. 1, 1884).
The study of the species referred to Aviculopecten from the Eureka District shows but one species that has such a hinge. A. affinis, A. Eure- kensis, A. peroccidens, A. Haguei have a flattened hinge, but in none of the examples of those species have we detected any vertical ligamental pits as in Crenipecten.
Crenipecten Hallanus, n. sp. Plate viii, figs. 7,7a-c. Shell rather above medium size; outline, exclusive of the ears, sub-
orbicular. General surface moderately convex. Hinge-line and greatest width of the shell as 4 to 5; 5 to 6 in two examples. Anterior ear smaller
232 PALEONTOLOGY OF THE EUREKA DISTRICT.
than the posterior, and also with an abruptly curved sinus beneathit. Beaks small and abruptly pointed, subcentral in position on the hinge-line.
Surface of both right and left valves marked by linear, radiating, raised strize that increase in number towards the margin by the striz originating in the gradually widening interspaces between the initial striae, the strize at the basal margin being about 1™” apart. Fine concentric striz cross the radiating elevated strize or coste.
The left valve of this species is closely allied to that of Crenipecten Winchelli (see Pal. N. Y., vol. v., pt. 1, p. 89), except in being more robust. In the right valve marked differences occur in the surface characters and the shape of the anterior ear. With Aviculopecten affinis it is more closely related, differing mainly in the form and proportion of the ears, in its more robust form, and the presence of the ligamental pits on the hinge-line, which, as yet, have not been observed in the latter, although the conditions for their preservation and discovery appear to be much better than in C. Hallanus.
Formation and localities —Lower portion of the Lower Carboniferous Group in the cation north of Pinto Peak, and also on the east slope of a small conical hill on the east side of Secret-canon-road Cation, Eureka District, Nevada.
Genus PTERINOPECTEN Hall. Pterinopecten Hoosacensis, n. sp. Plate viii, fig. 9.
Outline truncato-ovate. Left valve depressed convex. Hinge-line nearly as long as the greatest width of the shell below. Anterior ear de- fined by a strong rounded sinus; posterior ear scarcely more than a slight extension of the postero-lateral portion of the shell. Beak small, abruptly pointed, and situated a little anterior to the center of the hinge-line.
Surface marked by a few concentric lines of growth and fine, linear, raised striz that increase in number by intercalation as the initial striz spread apart, the intercalated striz appearing between them.
Dimensions: height, 4.5°™; breadth, 4.75.
FOSSILS OF THE CARBONIFEROUS. 233
In outline this species is not dissimilar from Pterinopecten (Pecten) papyraceus, as illustrated by De Koninck (Anm. Foss., plate v, figs. 6, 6 a, b). It differs widely in surface characters. I know of no American species with which to compare it.
Formation and locality—Lower portion of the Carboniferous Group, on the east slope of a small conical hill on the east side of Secret-cafion-road Cation, Eureka District, Nevada.
Pterinopecten Spio, n. sp.
Plate viii, figs. 1, la.
Outline, including the ears, broadly truncato-ovate. Left valve de- pressed convex. Hinge-line nearly as long as the greatest width of the shell below. Anterior ear small, separated more sharply from the body of the shell than is usual in the genus; sinus rounded; posterior ear large and not very distinctly separated from the body of the shell. Beak small, abruptly pointed, and situated nearly on the anterior third of the length of the hinge-line.
Surface marked by about 20 linear, radiating coste, with inter-spaces greater than the width of the cost, in which faintly-defined cost are sometimes shown; concentric lines of growth occur, and under peculiar conditions of preservation, as shown in fig. 1 of plate viii, form a reticu- lated structure with the radiating coste.
Dimensions : height of an average specimen, 15"; width, 18""; con- vexity of left valve, 2™™ to 3™™.
In outline and the form of the wings this species approaches that of Pterinopecten eafoliatus Hall, of the Devonian of New York (Pal. N. Y,, vol. v, pt. 1, p. 61, 1884), more nearly than to any other species known to me.
Formation and locality—Lower portion of Lower Carboniferous lime- stone in cation directly south of a small conical hill on east side of Secret- cafion-road Cation, Eureka District, Nevada.
234 PALEONTOLOGY OF THE EUREKA DISTRICT.
Genus PTERINEA Goldfuss.
Pterinea Pint6ensis, n. sp. Plate xix, fig. 10.
Shell very small; body part obliquely elongate, narrowing towards the beak, which extends a little above the hinge-line. ‘The anterior ear is small, rounded in front, and somewhat compressed; posterior ear large, compressed, extending beyond the posterior extremity of the valve, pointed at the end, and slightly sinuous behind. The body of the valve ranges at an angle of about 40° with the cardinal margin.
Surface marked by strong concentric striz.
This little shell has a length of 10™™ on the cardinal line and a height at right angles to this of 6™™. It is unlike any species known to me occur- ing at this horizon.
The generic reference to Pterinea is made in the absence of any knowledge of the interior characters. It is very probable that it belongs to the genus Actinopera, but with the material at hand this cannot be deter- mined.
Formation and locality—Lower portion of the Carboniferous Group, on northeast side of cation north of Pinto Peak, Eureka District, Nevada.
Genus LEPTODESMA Hall. Leptodesma, sp. ?
Two species of this genus are represented in the collections from the lower portion of the Carboniferous. One is quite strongly marked, and is allied to Leptodesma Rogersi Hall, of the Hamilton Group of New York, and the other to L. complanatum Hall, from the Chemung Group, New York (See Pal. N. Y., vol. v, pt. 1, pp. 176, 227). Each is represented by a single, not very well-preserved specimen, which renders a specific identification very uncertain and unsatisfactory.
FOSSILS OF THE CARBONIFEROUS. 235
Genus PTYCHOPTERIA Hall. Ptychopteria protoforme, n. sp. Plate viii, fig. 5.
Shell obliquely elongate, narrowing anteriorly; posterior ear broad and straight, anterior ear short; beak anterior, obtusely rounded; hinge line long, but not quite equaling the greatest width of the shell below.
Surface marked by obscure lines of growth.
Interior characters unknown.
‘Dimensions: height, 12"; greatest breadth, 20"; convexity of left valve, 2™™ to 3™™.
The outline of this species is more nearly like that of Ptychopteria Proto Hall (Pal. N. Y., vol.-y, pt. 1, p. 129, 1884) than that of any other species known to me. ‘The ear is not as broad, and it also terminates in a more acute angle with the hinye-line, in this respect resembling P. sinuosa Hall (loc. cit. p. 130).
Formation and locality—Lower portion of Lower Carboniferous lime- stone on east slope of a small conical hill on the east side of Secret-caiion- road Canon, Eureka District, Nevada.
Genus PINNA Linneus. Pinna inexpectans, n. sp. Plate xix, fig. 11.
Shell elongate, lanceolate, over four times longer than wide; section elliptical, valves not very convex; ventral and dorsal margins straight or slightly convex. -The dorsal or cardinal margin is a little thickened and with a well-defined rounded rim at the edge.
Surface marked by strong ridges subparallel to the dorsal and ventral margins; they are more or less flexuous, and while obsolete on the upper portion of some examples, are present on the entire width of the shell in others. A few obscure concentric lines, parallel to the posterior margin, cross the radiating plications.
236 PALEONTOLOGY OF THE EUREKA DISTRICT.
This species is allied to Pinna Missouriensis Swallow (Trans. St. Louis Acad. Sci., vol. ii, p. 97, 1863), but from the description of that species it appears to differ in form and surface markings. It differs from P. flexicostata McCoy (Brit. Pal. Foss., p. 499), in being more elongate, and also in hay- ing the radiating plications on the entire lower half of the valves.
Formation and locality.—Lower portion of the Carboniferous Group, on east slope of a small conical hill on the east side of Secret-canon-road Canon, Eureka District, Nevada.
Pinna consimilis, n. sp. Plate xx, fig. 13.
Valves elongate, about three and one-half times longer than the width at the posterior end; the upper and lower margins converging at an angle of 20° towards the beaks, where the shell is pointed and subcylin- drical, the section becoming more and more elliptical toward the posterior end, which is slightly and obliquely rounded ; cardinal margin a little thick- ened and with a narrow, well-defined, rounded rim or cardinal ridge.
Surface marked by concentric lines of growth; otherwise smooth.
The description is drawn from a small specimen 11° in length, but fragments of individuals of twice the size were found. The species is allied to P. spatula McCoy (Brit. Pal. Foss., p. 499), but differs in being less elon- gate in proportion to the width, the outline being more that of the plicated species, P. flewicostata McCoy (loc. cit., p. 499). I know of no closely related American species, P. subspatulata Worthen (Geol. Surv. Ill, vol. vi, p. 524), being a much more elongated form.
Formation and localities—Lower portion of the Carboniferous with the preceding species, and also on the northeast side of the cation north of Pinto Peak, Eureka District, Nevada. Also at about the same horizon on the west slope of Mokomoke Ridge, White Pine District, Nevada.
FOSSILS OF THE CARBONIFEROUS. 23H
Genus MYALINA De Koninck. Myalina congeneris, n. sp. Plate xix, fig. 6; plate xxii, fig. 10.
Shell oblong, the height being twice the width even in the broad ex- amples; hinge line straight and ranging at an angle of 60° with the nearly straight anterior margin; base narrow, but rather broadly rounded, poste- rior very broadly rounded, curving slightly inward towards the cardinal line. General surface of the valves strongly convex towards the front border, and beaks becoming more depressed on the posterior portion. Sur- face of both valves marked by slightly imbricated lamellz of growth.
The specimen illustrated is more narrow than a right valve associated with it that has all the essential characters of the species. Its specific rela- tions are with Myalina angulata M. and W. (Geol. Surv. IIL. vol. ii, p. 300), from which it differs in having a more obtuse Angle at the union of the car- dinal and anterior margins and a less oblique anterior margin. It is in out- line intermediate between M. angulata and M. subquadrata Shumard (Geol. Surv. Missouri., vol. i, pt. 2, p. 207, 1855); Myalina Apachesi Marcou (Geol. N. Amer., p. 44) may possibly be a closely allied species, but with the descrip- tion and figure given by its author this cannot be determined. . Compare, also, M. St. Ludovica Worthen (Geol. Surv. IIl., vol. v, p. 540).
Formation and locality.—Lower portion of the Carboniferous Group, on the west slope of Richmond Mountain, Eureka District, Nevada.
.
Myalina Nemesis, n. sp. Plate xix, fig. 5; plate xxii, fig. 7.
Shell subovate to subquadrangular, depressed convex, base broadly rounded; anterior margin slightly concave or straight, posterior outline broadly rounded and meeting the hinge-line at an obtuse angle. Hinge straight, shorter than the greatest width, and ranging at nearly right angles to the longitudinal axis of the shell. Beaks terminal and directed obliquely forward.
238 PALEONTOLOGY OF THE EUREKA DISTRICT.
Surface marked by concentric undulations of growth.
The original type of this species is the elongate compressed left valve illustrated on plate xix, fig. 5. Subsequently several specimens of the right valve were obtained from the same locality that show more nearly the true outline of the shell. The hinge-line varies in length, as do the relative pro- portions of the height and width of the valves, but these differences do not prevent the union of the several examples under one species.
In outline some of the shells approach Myalina ampla, M. and H. (Name proposed in description of species, Pal. Upper Missouri, p. 33).
Formation and locality—Lower portion of the Carboniferous Group in the canon northeast of Pinto Peak, Eureka District, Nevada.
Myalina Nessus, n. sp. . Plate xxii, figs. 8, 8a.
Shell large, subquadrate, narrowing towards the base, higher than wide, compressed posteriorly, becoming somewhat convex on the umbonal slopes. Hinge straight, fully equalling, if not exceeding, the greatest width of the valves, and ranging at nearly right angles to the vertical axis of the shell. Beaks terminal and directed obliquely forward.
Surface marked by concentric lamellze and undulations of growth.
Interior characters unknown.
Dimensions: height of large specimen, 10°; width, about 7™.
In size this species approaches Myalina ampla M. and H. (Pal. Upper Missouri, p. 33, 1855), and“fully equals Jf. subquadrata Shumard (Geol. Sury. Missouri, vol. 1, pt. 2, p. 207, 1855). It differs from the former species in the outline of the posterior side and in the narrowing of the lower portion of the shell, and also in the direction of the umbonal slope. The same dif- ferences exist between it and JZ. subquadrata. :
Formation and locality—Lower portion of Lower Carboniferous lime- stone on east slope of a small conical hill on the east side of Secret-canon- road Canon, Eureka District, Nevada.
FOSSILS OF THE CARBONIFEROUS. 239
Genus MODIOLA Lamarck. Modiola ? Nevadensis, n.'sp. Plate xix, fig. 8.
Shell thin, transversely elongate, narrow anteriorly, expanding gradu- ally to the greatest height at a point back of the center; anterior end narrow and abruptly rounded; basal margin but little curved except pos- teriorly; posterior end somewhat narrowly rounded, and then sloping obliquely upward and forward to its union with the nearly straight car- dinal line. Beaks small, depressed, anterior. General surface rather strongly convex anteriorly, and also backward along the broadly-rounded umbonal ridge.
Surface with fine concentric lines of growth.
With the single valves, and without specimens showing the hinge structure, the generic reference is more or less doubtful. The specimen illustrated has been accidentally compressed anteriorly, the basal margin having been pushed down and beneath its true position.
Formation and locality—Lower portion of the Carboniferous Group, on the low hills south of Newark Mountain by the side of Pinto Creek, Eureka District, Nevada.
Genus MODIOMORPHA Hall.
Modiomorpha ambigua, n. sp.
Plate xx, fig. 1.
Shell rather below the medium size, transverse and subquadrate for- ward to the line of the beaks, in front of which it contracts rapidly to a rather narrow, rounded lobe; beaks small, and situated on the anterior third; hinge-line slightly arcuate; posterior end broadly rounded to the nearly transverse basal margin, which isa little curved towards the anterior lobe.
Surface marked by faint concentric striz and a few stronger lines of growth.
240 PALEONTOLOGY OF THE EUREKA DISTRICT.
There is some doubt attending the reference of this species to the genus Modiomorpha, as the hinge structure and muscular impressions are unknown; but in the absence of these characters the general form of the shell allies it to that genus.
Formation and locality—Lower portion of the Carboniferous Group, on the east slope of a small conical hill on the east side of Secret-cation-road Canon, Eureka District, Nevada.
Modiomorpha ? desiderata, n. sp.
Plate xx, fig. 3.
Shell of medium size; transverse, roughly suboval; beaks small, com- pressed, and situated within the anterior third, the portion of the shell in front of them contracting quite rapidly and becoming abruptly rounded in front; the posterior end is broken away, but, from the direction of the lines of growth, it was probably somewhat broadly rounded. ‘The valves are moderately convex and the surface marked by a few lines of growth.
The nearest allied species appears to be Modiomorpha Hyalea Hall (Pal. N. Y., vol. v, pt. 1, Plates and Explanations, pl. xli, fig. 28, 1883), from the Waverly Group of Ohio.
As with the preceding species the generic reference is doubtful; and, although their generic relations are not clearly determined, it is thought desirable to give specific names to the well-marked species of the class to which they belong, as it is rarely well represented in the Carboniferous Group in the Rocky Mountains.
Formation and locality—Lower portion of the Carboniferous Group, on the east slope of a small conical hill on the east side of Secret-cation-road Canon, Nevada.
Modiomorpha ? PintGensis, n. sp. Plate xx, fig. 2. Shell of medium size, transversely subelliptical in outline; general surface moderately convex, with a rounded umbonal slope to the greatest posterior extension uf the valve on the lower third of the posterior margin;
FOSSILS OF THE CARBONIFEROUS. 241
anterior end contracted and abruptly rounded; basal margin broadly arcu- ate and meeting the slightly oblique posterior line so as to form a rounded angle; cardinal margin nearly straight and forming an obtuse angle at its union with the posterior margin.
Surface ornamented by numerous concentric striz.
Formation and locality —Lower portion of the Carboniferous Group, northeast side of canon north of Pinto Peak, Eureka District, Nevada.
Genus NUCULA Lamarek.
Nucula insularis, n. sp. Plate xx, fig. 14.
Shell transverse, broadly and irregularly ovate, strongly convex, and with the beaks prominent and incurved; anterior end contracted and rounded somewhat abruptly, the posterior end more broadly rounded and the basal line still more; the point of union of the two latter is almost subangular, the posterior margin sloping upward somewhat obliquely.
Surface marked by fine concentric strize and stronger varices of growth.
This species is allied to N. bellastriata Conr., and N. varicosa H. and W. (Pal. N. Y., vol. v, pt. 1, Plates and Explanations, pl. xlvi, 1883), of the Hamilton Group of New York.
Formation and locality—Lower horizon of the Carboniferous Group, east slope of a small conical hill on east side of Secret-canon-road Canon, Eureka District, Nevada.
Nucula levatiforme, n. sp. Plate xxii, figs. 1, la.
Shell very small, subtriangular in outline, moderately convex. Beaks elevated, incurved, situated on the anterior half of the shell. Surface marked by fine, strong, concentric, depressed lines of growth.
Interior characters unknown. 146cDW
242 PALEONTOLOGY OF THE EUREKA DISTRICT.
Dimensions: height, 6™"; *width, 7"; convexity or depth of right valve, 2™™.
This small species is more closely allied in external form to Nucula ? levata Hall (Pal. N. Y., vol. i, p. 150, pl. xxxiv, figs. 1 a-i, 1847), of the Trenton limestone of New York than to any Carboniferous species that I am acquainted with.
Formation and locality—Lower portion of Lower Carboniferous lime- stone in canon directly south of conical hill on east side of Secret-cation- road Canon, Eureka District, Nevada.
Genus SOLENOMYA Lamarck.
Solenomya curta, n. sp. Plate xxii, figs. 6, 11.
Outline transversely elliptical or oblong-oval, moderately convex. Hinge-line about one-half the length of the shell; beak depressed, situated at the anterior third of the shell.
Surface with narrow undulations of growth, crossed by nearly obso- lete, radiating, flat plications, with finer striz between.
Interior characters unknown.
Dimensions: height, 2.25™; width, 3.75™; convexity or depth of left valve, 5°. A smaller, more elongate right valve has a height of 1.5°™, and a width of 3°. With but one specimen of the latter to study it is referred to this species somewhat provisionally, as there is no series of forms unit- ing it with the former.
I know of no species with which this can be directly compared, its shorter, higher form distinguishing it from described species.
Formation and locality—Lower portion of Lower Carboniferous lime- stone on east slope of a small conical hill on the east side of Secret-cantion- road Canon, Eureka District, Nevada.
FOSSILS OF THE CARBONIFEROUS. 243
Genus MACRODON Lycett. Macrodon Hamiltone Hall. Plate xxiii, figs. 5, 5a-c. Macrodon Hamiltone Hall, 1870. Prelim. Notice Lam, Shells, 8vo., pamphlet, p. 13. Idem., 1883. Pal. N. Y., vol. v, pt. 1; Plates and Explanations, pl. li, figs. 1-10.
In comparing a large series of specimens referred to this species from Nevada, with the beautiful illustrations of it given in the Paleontology of New York, and also with specimens from the Hamilton Group of New York, I do not find sufficient differences on which to base a specific separation of the Nevada and New York shells, although the former occur in strata of Lower Carboniferous age, and the latter in the lower half of the Devonian Group. The differences are in the outline of the cardinal margin as com- pared with the majority of the New York specimens, and the apparently thicker shell. -The first is negatived by the occurrence of specimens of the same outline with the New York specimens, and the second is owing to the condition of preservation, the macerated, compressed shells of the Hamilton shales not preserving the original structure of the shell. The Nevada speci- mens show the large anterior muscular scar in the casts, but not the lateral teeth shown in many of the New York examples of the species.
Formation and locality—Lower portion of Lower Carboniferous lime- stone in canon directly south of a small conical hill on east side of Secret- canon-road Canon, Eureka District, Nevada.
Macrodon truncatus, n. sp. Plate viii, fig. 2.
Shell subrhomboidal, convex, with an undefined depression extending from the beak obliquely to near the center of the basal line; anterior side rounded, posterior side rounded below, nearly straight above. Hinge-line straight, nearly as long as the greatest width of the shell below. Umbo depressed, situated anterior to the middle of the valves; beak small, in- curved.
244 PALEONTOLOGY OF THE EUREKA DISTRICT.
Surface marked by concentric lines of growth and numerous fine radiating coste closely arranged.
Interior characters unknown.
Dimensions: height, 6"; width, 10"; convexity of left valve, 3". Right valve unknown.
This litttle shell is allied to Macrodon parvus W. and W. (Proc. Boston Soc. Nat. Hist., vol. viii, p. 299, 1862) of the Burlington Group of Iowa, and M. Chemungensis Hall (Pal. N. Y., vol. v, pt. 1; Plates and Explana- tions, pl. li, figs. 11-16, 1883), from the Chemung Group of New York. It is distinguished from each by its short form and strongly ornamented surface. The generic reference is made on the general character of the ex- ternal shell, as the hinge-line and internal characters are unknown.
Formation and locality—Lower portion of Lower Carboniferous lime- stone on east slope of a small conical hill, on the east side of Secret-canon- road Canon, Eureka, District, Nevada.
Genus GRAMMYSIA De Verneuil. Grammysia Hannibalensis Shumard (Sp.). Plate xx, fig. 4.
Allorisma hannibalensis Shumard, 1855. Geol. Surv. Missouri, vol. i, pt. 2, p. 206, pl. C, fig. 19. Grammysia hannibalensis Hall, 1870. Prelim. Notice Lam. Shells, p.62. Hannibalensis Meek, 1875. Pal. Ohio, vol. ii, p. 300, pl. xvi, figs. 5a—c. Hannibalensis Hall, 1883. Pal. N. Y., vol. v, pt. 1, Plates and Explana- tions, pl. 1xi, figs. 23-33.
After comparing the Eureka examples of this species with authentic specimens from the Waverly sandstone of Ohio, no reasonable doubt re- mained of their specific identity.
The species ranges from the Chemung Group of New York to the Waverly of Ohio, and at the base of the Carboniferous of Iowa and Mis- souri.
Formation and locality.—Carboniferous Group, lower portion, on east slope of a small conical hill on the east side of Secret-canon-road Canon, Eureka District, Nevada.
FOSSILS OF THE CARBONIFEROUS. 245
Grammysia arcuata Conrad (Sp.) Plate xx, fig. 5. Posidonia ? arcuata Conrad, 1841. Ann. Rep. Geol. Surv. New York, p. 53. Grammysia arcuata Hall, 1870. Prelim. Notice Lam. Shells, p. 56. (Leptodomus ?) arcuata Hall, 1883. Pal. N. Y., vol. v, pt. 1; Plates and Explanations, pl. 1xi, figs. 1-9.
Although this species is confined to the Hamilton Group of New York and Virginia, as far as heretofore known, we are unable to separate the Car- boniferous shell from it on good specific grounds. Its occurrence at this locality and horizon is not surprising, as we have in the Devonian, and also at this same locality, examples of as great a range of supposed limited species, ¢. g., Pleurotomaria nodomarginata, Schizodus cuneatus, ete.
Formation and locality —Lower portion of the Carboniferous Group on the east slope of a small conical hill on the east side of Secret-cafion-road Canon, Eureka District, Nevada.
Genus EDMONDIA De Koninck. Edmondia Medon, b. sp. Plate xxiii, fig. 6.
Shell transversely subelliptical, moderately convex, equivalve. Hinge- line slightly arcuate; beaks depressed, situated on the anterior third of the shell.
Surface marked by concentric lines and unduiations of growth.
Interior characters unknown.
Dimensions : height, 15™; width, 2.5; convexity of single valve, 0.5%.
The specimen illustrated is the only well-preserved one we have of this species. In some respects it approaches H. Burlingtonensis W. and W. (See Pal. N. Y., vol. v, pt. 1; Plates and Explanations, pl. Ixiv, figs. 19-29, 1883), of the Burlington limestone of Iowa, and the Chemung Group of New York, differing in its more elliptical form and depressed beak.
Formation and locality—Lower portion of Lower Carboniferous lime- stone on east slope of a small conical hill on the east side of Secret-canon- road Cation, Eureka District, Nevada.
246 PALEONTOLOGY OF THE EUREKA DISTRICT.
Edmondia ? circularis, n. sp. ‘ Plate xxii, fig. 9.
Shell large; general outline broadly ovate or subcircular, moderately convex, most prominent at the umbonal region. Hinge-line unknown, but probably arcuate; beaks depressed, curved over towards the cardinal line.
Surface marked by concentric lines of growth as far as known. In- terior characters unknown.
Dimensions : height, 5°"; width, 6°™; convexity of left valve, 1.5™.
I know of no species with which to compare this. The generic refer- ence is made on the general form and appearance, as nothing is known of the interior characters.
Formation and locality—Lower portion of Lower Carboniferous lime- stone in canon directly south of a small conical hill on east side of Secret- eaftion-road Canon, Eureka District, Nevada.
Genus PLEUROPHORUS King. Pleurophorus Meeki, n. sp.
Plate viii, fig. 3.
Shell small, longitudinally oblong, widening posteriorly; moderately convex on the line of the umbonal slopes from the beak to the postero- basal margin, forming a nearly rounded section from the basal to the cardi- nal margin. Hinge-line long and nearly straight, with a narrow but well- defined lunette. Beaks located very near the anterior extremity.
External surface of the shell unknown. The cast shows 5 or 6 ra- diating coste and traces of concentric lines of growth.
The anterior adductor-muscular impression is bounded by a rather strong ridge on the posterior side; pallial line simple and extending to the slightly-marked posterior-adductor muscular scar; teeth unknown.
This species is more nearly related to the English Permian species Pleurophorus costatus King (Mon. Perm. Foss., plate xv) than to any Ameri- ‘an form that Lam acquainted with. The narrow form and posterior expan- sion serve to distinguish it from described species of the genus.
Formation and locality.—Lower portion of Lower Carboniferous lime- stone in canon directly south of a small conical hill on east side of Secret- canon-road Canon, Eureka District, Nevada.
FOSSILS OF THE CARBONIFEROUS. 247
Genus SANGUINOLITES McCoy.
In the absence of the structure of the hinge-line, the muscular scars, and pallial impression in the following species, there is some uncertainty in referring them to this genus, as in their general external appearance they resemble more or less forms referred to the Modiomorphide.
Sanguinolites Holus H. & W. Plate xx, figs. 6, 7, 9.
Sanguinolites wolus Hall, 1870. Prelim. Notice Lam. Shells, p. 46. ? wolus Meek, 1875. Pal. Ohio, vol. ii, p. 307, pl. xvi, figs. lac. Aolus Hall, 1883. Pal. N. Y., vol. v, pt. 1, Plates and Explanations, pl. Ixvi, figs. 31-35, 43.
The specimen illustrated by fig. 6 is a typical form of this species, cor- responding to those from the Waverly sandstone of Ohio, and we cannot distinguish the shorter, broader shells, as shown by figs. 7 and 9, as a dis- tinct species, as there is a complete gradation of form between them, and to even astill broader variety that is designated in the systematic list as S. Holus, var. A small shell of this species from the same locality resembles very closely some examples of Sanguinolites rigidus, an illustration of which is given from the Devonian limestone on plate xvi, fig. 6.
Formation and locality—Lower portion of the Carboniferous Group on the east slope of a small conical hill on the east side of Secret-canon-road Canon, Eureka District, Nevada
Sanguinolites retusus, nD. sp.
Plate xx, fig. 10.
Shell broad, irregularly ovate; moderately convex; beaks anterior, small and compressed; umbonal slope distinctly angular and extending from the beaks to the postero-basal angle, the somewhat rapidly sloping postero-cardinal slope being marked midway by a slight longitudinal ridge. Cardinal line short and a little arcuate; basal line broadly rounded, uniting posteriorly with the slightly rounded, oblique posterior line to form a
248 PALEONTOLOGY OF THE EUREKA DISTRICT.
rounded, obtuse angle, and rounding up more rapidly anteriorly in the more abruptly curved end.
Surface marked by concentric lines of growth, and in well-preserved examples fine concentric striz are visible.
This species is readily distinguished by its rotund outline from the associated species.
Formation and localities —Associated with the preceding, and also on the northeast slope of the canon north of Pinto Peak, Eureka District,
Nevada.
Sanguinolites simplex, n. sp.
Plate xx, fig. 11.
Shell rather above the average size, transverse, irregularly broad-ovate, beaks small, compressed, and situated on the anterior third of the shell; umbonal slope angular from the beak to the posterior basal angle; general surface of the valves moderately and regularly convex, except the postero- cardinal slope, which falls away more rapidly from the umbonal ridge; it is marked by a faint, central longitudinal ridge. The general outline is not very much unlike that of the preceding species, except in the more pointed extremities and the near approach of the umbonal ridge to the postero- cardinal margin.
Surface marked by fine concentric strize, and a few stronger lines of growth.
Formation and locality—Lower horizon of the Carboniferous Group, eastern slope of a small conical hill on the east side of Secret-canon-road Canon, Eureka District, Nevada.
Sanguinolites Salteri, n. sp.
Plate xx, fig. 12.
Shell rather small, transversely elongate, nearly three times as long as high; cardinal and basal margins subparallel or slightly diverging on the posterior half of the shell; beak small, depressed, and situated near the anterior end, which is narrow, short, and abruptly rounded; basal margin
FOSSILS OF THE CARBONIFEROUS. 249
nearly transverse along the center, curving up rather abruptly anteriorly, and more gently at the posterior end; posterior line abruptly rounded at the point of greatest extension on a line with the center of the shell, above which it curves forward to the straight cardinal line. Valves marked by several distinct, but not prominent, ridges on the postero-cardinal slope.
Surface ornamented by fine concentric strize, and a few obscure lines of growth.
Formation and locality—lLower horizon of the Carboniferous Group, eastern slope of a small conical hill on east side of Secret-cation-road Canon, Eureka District, Nevada.
Sanguinolites ? Nezenia, n. sp.
Plate xix, fig. 9.
Shell small, transversely elongate, the height being one-half the length; beaks small, depressed, and situated on the anterior third; anterior end nar- row, somewhat elongate and so abruptly rounded as to be almost angular; basal line slightly sinuate midway and curving up at each end; posterior end broadly rounded; cardinal line nearly straight The general surface of the valves is moderately convex, with a slight. umbonal ridge extending from the beak to the postero-basal curve, and also a rather broad, shallow mesial depression.
Surface marked by several well-defined, concentric undulations of growth.
Formation and locality—Lower horizon of the Carboniferous Group, eastern slope of a small conical hill on east side of Secret-canon-road Canon, Eureka District, Nevada.
Sanguinolites striatus, n. sp. Plate xxili, fig. 7. Shell transversely elongate-oval, compressed convex, posterior umbonal
slope angular. Cardinal line long, straight. Beak appressed, situated at about the anterior third.
250 PALEONTOLOGY OF THE EUREKA DISTRICT.
Surface marked by strong concentric strize that curve up rather abruptly in crossing the angular umbonal ridge.
Interior characters unknown.
There are three specimens preserving the anterior portions of the shell, but none showing the entire outline. The specimen illustrated has the — form we have considered as belonging to the genus Sanguinolites.
The strongly striated surface distinguishes it from described species known to me.
Formation and locality —Lower portion of Lower Carboniferous lime- stone, on east slope of a small conical hill on the east side of Secret-canon- road Canon, Eureka District, Nevada.
Genus MICRODON Conrad.
(CYPRICARDELLA Hall.) Microdon (Cypricardella) connatus, n. sp. Plate xxiv, figs. 5, 5a.
Shell transversely subovate or subrhomboidal, moderately convex. Hinge-line about two-thirds the length of the shell. Beaks small, depressed, and situated on the anterior third of the shell.
Surface marked by rather distinctly defined concentric strie.
The interior cast shows an anterior adductor muscular scar of medium size, also an undefined depression extending from the beak obliquely back- ward on the line of the umbonal ridge.
Dimensions: height, 1.75™; length, 3°"; convexity of the two valves united, 1°.
In form this species approaches very closely to Microdon (C.) gregarius Hall, and in surface characters WM. (C.) bellistriatus Conrad (Pal. N. Y., vol. y, pt. |; Plates and Explanations, pls xxiii, Ixxiv, 1883). While differing from both, it combines, in a measure, the specific characters of each.
The reference of this and also the Devonian MZ. macrostriatus (ante, p. 180) to the genus Microdon is tentative. Professor Hall proposed the name Eodon as a substitute for Microdon, as the latter had already been used for a genus
FOSSILS OF THE CARBONIFEROUS. 251
of fishes and a genus of insects (Miller’s Cat. Pal. Foss., Addenda, p. 244, 1877). In the Paleontology of New York (vol. v, part 1; Plates and Ex- planations, p. 18, 1883), a second generic name is placed between Microdon and Kodon, viz, Microdonella. Professor Hall previously described the genus Cypricardella for similar forms from the Warsaw limestone (see remarks by Mr Whitfield, Bull. Amer Mus. Nat Hist, vol. i, No. 3, p. 63), and if Micro- don is dropped Cypricardella will have to be substituted.
Formation and localities—Lower portion of Lower Carboniferous lime- stone in the canon north of Pinto Peak, and also on the east slope of a small conical hill on the east side of Secret-canon-road Canon, Eureka District, Nevada.
Genus CARDIOLA Broderip. Cardiola ? filicostata, n. sp.
Plate xxii, figs. 4, 4a.
Shell obliquely oval, moderately convex. Beak somewhat elevated, small and incurved.
Surface marked by fine, radiating, slightly irregular, elevated striz, and a few concentric lines of growth.
Interior characters unknown.
Dimensions: height, 1.5°™; width, 2%; convexity or depth of left valve, 0.5°™.
_ The generic reference is doubtful, owing to the absence of the interior characters, and also the strong surface coste, so characteristic of Cardiola. The only related species referred to the genus is Cardiola transversa Hall (Pal. N. Y., vol. v, pt. 1; Plates and Explanations, pl. Ixx, figs. 12-15).
Formation and locality—Lower portion of Lower Carboniferous lime- stone on east slope of a small conical hill on the east side of Secret-canon- road Canon, Eureka District, Nevada.
252 PALEONTOLOGY OF THE EUREKA DISTRICT.
Genus SCHIZODUS King.
Schizodus cuneatus Meek. Plate xx, fig. 8.
Schizodus cuneatus Meek, 1875. Pal. Ohio, vol. ii, p. 336, pl. xx, fig. 7.
There does not appear to be any points of specific difference between the Ohio shell illustrated by Mr. Meek and the examples of this species from Nevada. The latter are proportionally a little narrower, but this may be owing to the state of preservation, as the Ohio shell is compressed in a shale, and the Nevada specimens retain their natural convexity and outline.
Formation and locality —Lower portion of the Carboniferous group, on the eastern slope of a small conical hill on the east side of Secret canon- road Canon, Eureka District, Nevada.
Schizodus deparcus nD. sp.
Plate xxii, fig. 5.
Shell large, transversely suborbicular, moderately convex; umbonal ridge rounded and passing into the postero-dorsal slope without any per- ceptible angle being developed. Beak small, elevated, incurved, and sit- uated a little anterior to the center of the shell.
Surface smooth as far as known, except a few radiating lines on the postero-dorsal slope.
Anterior muscular scar not large, ovate in outline; posterior scar elon- gate, and crossed longitudinally by two slightly depressed lines, probably from the radiating lines of the postero-dorsal slope of the shell. Pallial line simple.
Dimensions: height, 4.25™; width, 5°"; convexity or depth of right valve, 1.5°™. In size this species approaches Schizodus cuneatus (ante). It differs in being less erect, less angular in outline, and in having a smooth surtace.
Formation and locality—Lower portion of Lower Carboniferous lime- stone on east slope of a small conical hill on the east side of Secret-canon- road Canon, Eureka District, Nevada. j
FOSSILS OF THE CARBONIFEROUS. on
od Schizodus curtiforme, n. sp.
Plate xxii, figs. 3, 3a.
Shell small, subrhomboidal, moderately convex; posterior dorsal region back of the umbonal ridge compressed and cuneate; umbonal slope dis- tinctly angular from the beak to the postero-basal margin; anterior slope rather abrupt to the anterior margin. Beak elevated, incurved, and situated a little anterior to the center.
Surface of the cast with a few indications of concentric lines of growth.
Interior characters unknown.
Dimensions: height, 1.5°™; width, 1.75°; convexity or depth of right valve, .5°™.
This little species is related to Schizodus curtus M. and W. (Geol. Sury. Ill, vol. v, p. 582), and 8. Rossicus De Vern. (Russ. and Ural Mts., p. 309), but can scarcely be referred to either specifically.
Formation and locality—Lower portion of Lower Carboniferous lime- stone in canon directly south of a small conical hill on east side of Secret- canon-road Canon, Eureka District, Nevada.
Schizodus Pintcensis, n. sp.
Plate xxii, figs. 2, 2a.
Shell about the average size of species of the genus; outline obliquely subrhomboidal; base strongly arcuate; umbonal slope distinctly angular, with the posterior side flattened; general surface moderately convex, cury- ing evenly over the central portions anterior to the umbonal angle and then more abruptly down to the anterior margin. Beaks elevated, incurved, and placed on the anterior third of the shell.
Surface of cast showing a few lines of growth.
Dimensions: height, 2; width, 2.25°"; convexity or depth of left valve, 0.5°™.
Some of the examples are more oblique, and have the appearance of being more erect, owing to the greater curvature of the basal margin. This is shown in the illustration of the right valve.
254 PALEONTOLOGY OF THE EUREKA DISTRICT.
In comparing with Schizodus cuneus Hall, from the Waverly Group (Pal. N. Y., vol. v, pt. 1; Plates and Explanations, pl. Ixxv, figs. 27-30), a strong resemblance is apparent, the Nevada shell differing only in its more robust form and in the strongly arcuate basal and anterior margins.
Formation and locality—Lower portion of Lower Carboniferous lime- stone, in the canon northeast of Pinto Peak, Eureka District, Nevada.
GASTEROPODA. Genus PLATYCERAS Conrad.
Platyceras occidens, n. sp.
Plate xxiv, figs. 9, 9a.
Shell obliquely subconical, apex minute and strongly incurved, the nucleus making about one volution and then rapidly expanding; the dor- sum is somewhat abruptly rounded but not carinate; the right side is gently and evenly convex to the rounded angle formed by the union with the front; the left side is more abruptly convex, and curves forward impercep- tibly into the anterior surface. Aperture subtriangular in outline with the peristome sinuous.
Surface marked by fine, well-defined, undulating strize of growth.
This is a small and very pretty species. It may be compared with some forms of Platyceras carinatum Hall (Pal. N. Y., vol. v, pt. 2, p. 5, pl. ii, figs. 12-29) of the Devonian.
Formation and locality—Lower portion of Lower Carboniferous lime- stone, in canon directly south of a small conical hill on east side of Secret- eanon-road Canon, Kureka District, Nevada.
Platyceras Piso, n. sp. Plate xxiv, figs. 7,7 a, b.
Shell obliquely and strongly arcuate; apex minute, incurved, making about one volution; body-whorl expanding rather rapidly at first and then very gradually to the aperture; dorsum rounded; sides and dorsum with seven or eight slight longitudinal plications; aperture broadly subovate
with the peristome sinuous.
FOSSILS OF THE CARBONIFEROUS. 255
Surface covered with fine, undulating strive of growth that are crowded together irregularly, forming slight concentric undulations.
The arcuate form of the body-whorl distinguishes this species from Platyceras acutirostris Hall (Geol. Surv. lowa, vol. i, pt. 2, p. 665, pl. xxiii, fig. LL) of the Lower Carboniferous of Indiana, ete., the most nearly allied species.
Formation and locality—Lower portion of Lower Carboniferous lime- stone, in canon directly north of a small conical hill on east side of Secret- canon-road Canon, Eureka District, Nevada.
Genus PLATYOSTOMA Conrad. Platyostoma inornatum nN. sp. Plate xxiv, figs. 3, 3a.
Shell subglobose; spire elevated above the body whorl; volutions three or four, and perhaps a fifth very minute one, that is not preserved in the specimen illustrated. The outer volution expanding towards the aperture, but scarcely ventricose; aperture vertically ovate or subrhomboidal; the columellar lip appears to have been reflexed.
The few fragments of the outer shell that are preserved show it to
have been nearly if not quite smooth. This species resembles some forms of Platyostoma lineatum (ante, p. 185)
of the Devonian of New York.
Formation and locality—Lower portion of Lower Carboniferous lime- stone, in canon directly south of a small conical hill on the east side of Secret- canon-road Canon, Kureka District, Nevada.
Genus EUOMPHALUS Sowerby.
Buomphalus (Straparollus) subrugosus M. & W. Plate xviii, fig. 19. Euomphatus rugosus Hall, 1858. Geol. Surv. Iowa, vol. i, pt. 2, p. 722, pl. xxix, figs. 14a-c. (Not Huomphalus rugosus Sowerby, 1849.)
Serpula (Spirorbis) planorbites Geinitz, 1866. Carb. und Dyas in Nebraska, p. 2, pl. i, fig. 6, (not of Munster).
256 PALEONTOLOGY OF THE EUREKA DISTRICT.
Straparollus (Huomphalus) rugosus Meek, 1872, U.S. Geol. Sury. Nebraska, p. 230 pl. vi, figs. 5 a,b; pl. xi, figs. 44, b. Straparollus (Gdomphaie) subeanate Meek & Worthen, 1875. Geol. Surv. Illinois, vol. v, p. 607, pl. xxix, figs. 11 a-e. é The example of this species in the collection has the essential features. observed in the specimens from the Coal Measures of Illinois, Nebraska, ete., and no specific differences are recognized between the form from Nevada and those of the Mississippi Valley region. Formation and locality.—Lower portion of the Gaahanderans Group, on the east slope of a small conical hill on the east side of the Secret-canon- road Canon, Eureka District, Nevada.
Genus BELLEROPHON Montfort.
Bellerophon majusculus, n. sp. Plate xxiii, figs. 1, 1a; plate xxiv, fig. 6.
Shell thick and strong, very large, subglobose; body volution subglo- bose, expanded a little at the aperture, marked by a well-defined median. carina; outer lip with a strong sinus in front, rounded at the sides, somewhat reflexed and greatly thickened over the umbilical areas, entirely concealing the openings. Inner margin of the columellar lip very much thickened, boss-like, extending out into the aperture and giving the latter a broadly subreniform outline; the outer lip probably extended over a portion of the columellar lip, but the specimens at hand do not show this clearly.
Surface characters mostly obliterated, a few of the stronger lines or wrinkles of growth alone remaining; these curve gently forward between the dorsal carina and the umbilicus.
Dimensions: greatest length, 12™; breadth at umbilicus, 7.5™; at ap- erture, 11°. Aperture, 3.5°™ by 7.5 in a specimen 10™ long, by 6.5™ wide at the umbilicus.
This large Bellerophon is most nearly related to Bellerophon costatus Sowerby, as figured by De Koninck (Anm. Foss., plate xxvi, fig. 2 a-e). It differs in the direction of the lines of growth, form of aperture, and the thickening of the columellar lip. Bellerephon crassus M. and W. (Geol. Surv. Ill., vol. ii, p. 385, pl. xxxi, figs. 16a, b), from the Lower Coal Measures of
FOSSILS OF THE CARBONIFEROUS. 257
Illinois, is the largest American species of the genus.
It varies materially from B. majusculus in the character of the columellar lip.
Formation and locality—lLower portion of Lower Carboniferous lime- stone in a canon a little north of Pinto Peak, Eureka District, Nevada.
Fig. 3.—Section of the large specimen figured on plate xxiii, fig. 6. The chamber of the interior whorls is filled in with calcite, which leaves only the outer whorl clearly outlined, including a section of its chamber.
Bellerophon textilis Hall ? Plate xviii, fig. 18. Bellerophon cancellatus Hall, 1856,
Trans. Albany Inst., vol. iv, p. 31 (not B. cancel- latus Hall, 1847, Pal. N. Y., vol. i, p. 307). Bellerophon textilis Hall, 1877.
Proposed instead of B. cancellatus Hall (preoccupied). Miller’s Cat. Amer. Pal. Foss., p. 243.
Our specimens are all more or less crushed and distorted, but com- lj cD WwW
258 PALEONTOLOGY OF THE EUREKA DISTRICT.
parisons with examples of B. textilis from the Warsaw limestone of Indiana exhibit strong specific resemblances which, in the absence of more perfect specimens to show possible differences, place the Eureka shell in the same species.
Two other species occur in the same beds; one is like B. sublevis Hall, 1856 (‘Trans. Albany Inst., vol. iv, p. 32), of the Warsaw limestone, and the other is of the character of B. ellipticus McChesney (see Trans. Chicago Acad. Sci., vol. i, p. 44), from the Coal Measures of Illinois, but there is not sufficient material to decide conclusively upon the specific relations.
Formation and locality—Lower portion of the Carboniferous Group, east side of Secret-canon-road Canon on east slope of a small conical hill, Eureka District, Nevada.
Genus LOXONEMA Phillips.
Loxonema bella, n. sp.
Plate xxiy, figs. 1, la.
Shell small elongate-conical ; spire elevated, tapering to an acute point. Volutions fourteen to fifteen, very slightly convex, increasing gradually in size to the last one, which is a little enlarged and rather abruptly rounded below the middle.
Suture close but not deep. Aperture subovate or subrhombic, longer than wide.
Surface smooth to the unaided eye, but under a strong magnifying glass shows fine concentric strize of growth that curve slightly forward; at the suture these are a little stronger.
Dimensions: length, 18°"; breadth of body volution, 7"; divergence of apical angle, 24°.
In many particulars this species is closely allied to Loxonema cerithifor- mis M. and W. (Geol. Surv. IL, vol. ii, p 379, pl. xxxi, figs. 13 ac), and Chemnitzia subconstricta De Koninck (Anm. Foss., plate viii, figs. 17 a, 0). It differs from each in having less convex volutions, and the surface strize at the suture are not gathered in short crenulations. The cast has the form of the volution shown in both Meek’s and De Koninck’s figures.
FOSSILS OF THE CARBONIFEROUS. 259
The slope of the spire of L. bella is more like that of the minute Chem- nitzia levigata Deshayes (Leth. Rossica, pl. xlii, figs. 6a,b) of the Tertiary.
Formation and locality=—Lower portion of Lower Carboniferous lime- stone, in canion directly south of a small conical hill on the east side of Secret- canon-road Canon, Eureka District, Nevada.
Genus PLEUROTOMARIA Defrance.
Pleurotomaria nodomarginata McChesney. Plate xviii, fig. 15.
Pleurotomaria nodomarginata McChesney, 1860. Desc. New Species of Fossils, p. 70. Trans. Chicago Acad. Sci., 1869, vol. i, p. 47, pl. vii, figs. 1 a-c.
Notwithstanding that Mr. McChesney gives the Hamilton Group as the horizon from which P. xodomarginata was obtained, the identification is here made with a shell coming from the Lower Carboniferous of the Eureka Dis- trict. This conclusion is arrived at only after the most careful comparisons, which appear to leave very little if any doubt of the specific identity of the Nevada and Missouri shells.
Formation and locality —Lower portion of the Carboniferous Group, east side of Secret-canion-road Cation on east slope of a small conical hill, Ku-
reka District, Nevada.
Pleurotomaria Nevadensis, n. sp. Plate xxiv, figs. 2, 2a.
Shell turbinate; spire elevated, height and width subequal; volutions five or six, expanding quite regularly to within a half of a volution of the aperture, when it becomes more ventricose; body volution angulated, depressed convex above and rounded below; umbilicus small. Aperture broadly oval to subcircular.
Surface marked by strong, regular, revolving lines above and below the peripheral band, crossed and cancellated by finer concentric strie that cut into the revolving lines and give them a fine nodose appearance. ‘The concentric strie are directed a little backward from the suture to the band;
260 PALEONTOLOGY OF THE EUREKA DISTRICT.
arching backward in crossing the rather narrow surface defined by the sim- ple carina above and below, they trend forward at about the same angle to the suture as they do above from the band to the suture.
Formation and locality—Lower portion of Lower Carboniferous lime- stone, in canon direetly south of a small conical hill on east side of Secret: canon-road Canon, Kureka District, Nevada.
Genus MACROCHEILUS Phillips. ~ Macrocheilus, sp.? Plate xxiv, fig. 8.
The general form of this species is not unlike that of Macrocheilus Altonensis Worthen (Geol. Surv. IL, p. 593, pl. xxviii, fig. 8) of the Coal Measures of Illinois. Owing to the imperfect preservation of the aperture, it is impossible to make a satisfactory specific reference.
Formation and locality—Lower portion of Lower Carboniferous lime- stone, in canon directly south of a small conical hill on east side of Secret- canon-road Canon, Eureka District, Nevada.
Genus METOPTOMA Phillips. Metoptoma peroccidens, n. sp. Plate xviii, fig. 16.
Shell depressed, patelliform, rounded quadrangular or suboval in out- line, the greater and less diameters being 26™" and 20"; apex subcentral, with the sides sloping away uniformly to the lateral margins and not quite as rapidly to the anterior and posterior margins.
Surface marked by fine concentric lines or strize of growth and narrow radiating lines of a darker color. The original color of the shell is par- tially preserved, the dark radiating lines of color on the purplish-gray sur- face giving it the appearance of a recent Acmeea (A. testudinalis).
Formation and locality—Lower portion of the Carboniferous Group, Richmond Mountain, Eureka District, Nevada.
FOSSILS OF THE CARBONIFEROUS. 261
Genus AMPULLARIA Lamarck.
Ampullaria ? Powelli Walcott. Ampullaria ? Powelli Walcott, 1883. Science, vol. ii, p. 808, figs. 3, 3a.
Shell subglobose; umbilicus small; spire depressed; volutions three or four, increasing uniformly in size until the last one, which is larger in pro- portion and slightly expanded at the aperture; suture dis- tinct; aperture oblong, broad ovate, and a little straightened on the inner side, entire; peristome continuous, slightly reflexed.
Surface marked by fine lines of growth. Operculum ;
Fie. 4.— Outline figure of a typi- cal shell, X 3.
concentric, rather thick, and of a calcareous or shelly struct- ure; nucleus subcentral.
In referring this species to the genus Ampullaria we bear in mind that it is not probable that a genus of this 6) character has continued from the Middle Paleozoic to the ——_ present time; on the other hand, when we consider that the a ieee shell is Ampullaria-like in character and associated with an operculum that is almost characteristic of the genus, that the’ genus Pupa is known from the Middle Carboniferous, and that a shell not to be distinguished from . the recent Physa is associated with Ampullaria? Powell, a pulmonif- erous shell Zaptychius Carbonaria and a twig of a coniferous tree, all of which are evidences of a near land area, it would appear that a reference to Ampullaria, as the genus representing the group to which the species belongs is warranted by the facts, although it may be ultimately referred to a new genus or subgenus.
Formation and localities —Lower portion of the Carboniferous Group, on the western slopes of New York and Richmond Mountains, Eureka Dis- trict, Nevada.
PULMONIFERA.
For an excellent summary of what was known of the Paleozoic rep- resentatives of this subclass up to the month of November, 1880, we are indebted to Dr. J. W. Dawson, who states that the three known localities of their occurrence are on the American continent, and that six species were
262 PALEONTOLOGY OF THE EUREKA DISTRICT.
described from them, namely: Pupa vetusta, P. Bigsbyi Dawson, Zonites (Conulus) priscus Carpenter, from the Coal Measures of the South Joggins, Nova Scotia; Pupa Vermillionensis, Dawsonella Meeki Bradley, from the Upper Coal Measures of Vermillion River, Illinois, and Strophites grandeva Dawson, from the Devonian plant beds of St. John, New Brunswick (Amer. Journ. Sci., 3d ser., vol. xx, p. 403, 1880). Subsequently Prof. R. P. Whit- field gave the results of his study of Dawsonella Meeki, showing that it was probably an operculate shell, and he also described. Anthraco-pupa Ohioensis from the higher beds of the Coal Measures at Marietta, Ohio ([bid., xxi, p- 125, .881). All of the species are true land shells, the aquatic division of the Pulmonifera being unrepresented up to the time of the discovery in Nevada of the species to be described. The geologic horizon at which the latter occur is intermediate in position to the Devonian plant beds of New Brunswick and the localities in the Coal Measures of Nova Scotia, Illinois, and Ohio. .
A brief notice of these shells was published in Science, vol. ii, p. 808, 1883. .
Genus PHYSA Draparnaud. Physa prisca Walcott.
Physa prisca Walcott, 1883. Science, vol. ii, p. 808, fig. 2.
Shell small, oblong, sinistrally spiral, and with about four volutions, the last one expanded, ventricose, with the short, small spire above less than one-fourth its length; aperture more than three- fourths of the length of the body volution, broadly rounded anteriorly, becoming more pointed at the opposite end; outer lip thin, inner lip slightly reflected on the last whorl.
Surface smooth or marked by fine lines of growth. ;
The shell is apparently that of a true Physa, although wofehaly 3. thicker than in most species of the genus. It may belong to a subgeneric group, but of this we have little evidence in the specimens before us.
The largest specimen has a length of 9", and the smallest of 4™™.
Formation and localities—Lower portion of the Carboniferous Group, in a chocolate-colored limestone, on the western slope of New York and Richmond Mountains, Eureka District, Nevada.
FOSSILS OF THE CARBONIFEROUS. 263
Genus ZAPTYCHIUS, n. g.
Shell minute, elongate; aperture large, oblong nearly vertical; outer lip thin, columellar lip reflected, plicated.
Surface of shell marked by slightly oblique longitudinal striz.
Type: Zaptychius carbonaria.
Zaptychius appears to have its nearest living ally in Auricula, although differing in the form of the body volution and spire from the typical forms of that genus; the presence ot the Auricula-like aperture and clongate shell, vertically striated, afford the basis for a new generic description.
Zaptychius carbonaria Walcott. Zaptychius carbonaria Walcott, 1883. - Science, vol. ii, p. 808, fig. 1.
Shell small, slender, the body volution having a length of about 6.5™", and a greater diameter of 2.5"; aperture rather large, elon- gate, narrow posteriorly and broadly reunded in front; col- umellar lip thickened anteriorly, the thickened portion cury- ing inward opposite the umbilical chink to form a rounded plication or ridge on the lip, which is reflected back on the volution and marked by a second tooth-like plication pro- jecting a short distance out into the aperture a little posterior to the first. The number of volutions is unknown.
Surface of the shell marked by even, equidistant, nearly vertical strize that distinctly define the interspaces between them.
The form of the spire above the portion of the volution preceding the body volution is unknown, although from the ey Bare character of that preserved and the presence of a trace of a volution 3.5™ above the body volution, it was probably more or less slender and elongate.
Formation and locality—Lower portion of the Carboniferous formation, in a chocolate-colored limestone, associated with Physa prisca and Ampulla-
ria ? Powelli, Eureka District, Nevada.
264 PALEONTOLOGY OF THE EUREKA DISTRICT.
PTEROPODA.
Genus CONULARIA Miller.
Conularia Missouriensis Swallow ? Plate xxiii, fig. 4. Conularia Missouriensis Swallow, 1860. ‘Trans. St. Louis Acad. Sci., vol. i, p. 657.
The description given by the author of this species agrees so closely with the specimen before me that in the absence of the type, or a good illustration, it is identified with it. Both the Missouri and Nevada speci- mens occur in the lower portion of the Lower Carboniferous limestone.
Formation and locality—Lower portion of the Lower Carboniferous limestone, Mokomoke Ridge, White Pine Mining District, Nevada.
Genus HYOLITHES BHichwald. Hyolithes carbonaria, n. sp.
Plate xxiii, fig. 3.
Form an elongate triangular pyramid, gradually and regularly taper- ing to an acute extremity; angle of divergence of the sides, 18°. Trans- verse section subovate, slightly convex on the ventral side, the lateral mar- gins rounded, and the dorsal side a little more convex than the opposite side. Aperture oblique, the ventral side being a little prolonged. Shell rather thick. Operculum unknown.
Surface with fine, concentric, radiating or longitudinal striz.
Dimensions: length, 11™"; diameter at aperture, 3.5"™ by 2™™.
In the cast a longitudinal groove is seen on the ventral face near each lateral margin; it extends only a little way back from the aperture.
This pretty little shell has the form of Hyolithes aclis Hall (Pal. N. Y., vol. v, pt. 2, p. 197), of the Devonian of New York, but it is more slender and probably a much smaller species. Also compare with Hyolithes novellus Barrande (Syst. Sil. Bohéme, vol. iii, pl. xv, figs. 23, 24.)
Formation and locality—Lower portion of Lower Carboniferous lime- stone, in canon directly south of a small conical hill on the east side of Secret-canion-road Cation, Eureka District, Nevada.
FOSSILS OF THE CARBONIFEROUS. 265
CEPHALOPODA. Genus ORTHOCERAS Breynius.
Orthoceras Randolphensis Worthen? Plate xviii, fig. 17.
Orthoceras annulato-costatum Meek & Worthen, 1861. Proc. Acad. Nat. Sci. Philad., vol. xiii, p.147. Ibid., 1866. Geol. Illinois, vol. ii, p. 304, pl. xxiv, figs. 3a. (Not Orthoceras annulato-costatum Boll, 1857.)
Orthoceras Randolphensis Worthen, 1882. Bull. Ill. State Mus. Nat. Hist., No.1, p. 38. By error in the Bulletin the original reference of this species is given as Orthoceras annulo-costatum M. & W., 1862, Geol. Surv. IIl., vol. vi, instead of as above.
With the means of comparison at hand the fragmentary remains of this form from Nevada appear to be identical with those from the Chester lime- stone of the Lower Carboniferous formation of the State of Illinois. The most marked difference between them is the greater obliquity of the annu- lations in the Nevada specimens, but this may be owing in a measure to the crushing of the tube, which is compressed very much in all the examples collected.
Formation and locality —Lower portion of the Carboniferous limestone, on the eastern slope of a small conical hill on the east side of Secret-canon- road Canon, Eureka District, Nevada.
Orthoceras Eurekensis, n. sp. Plate xxiii, figs. 2, 2a.
Shell slightly curved. Transverse section broadly oval; the dorso- ventral diameter the shorter, having a ratio of 7 to 8 with the lateral diam- eter. Tube gradually and regularly enlarging. Chamber of habitation unknown. Air-chambers have a depth of 4"™ where the dorso-ventral diameter of the tube is 14™™. Septa thin, smooth, moderately concave. The suture has a broad retral curve over the dorso-ventral sides of the tube, extending forward over both the lateral faces.
Siphuncle small, slightly eccentric, and nearer the dorsal face of the septum; a narrow, flat areola surrounds it in the one section exposed to
266 PALEONTOLOGY OF THE EUREKA DISTRICT.
view. The character of the siphuncle in its passage between the septa has not been observed.
The test is rather strong, and is vertically striated on the interior as shown in the cast, the strie being exceedingly fine. The exterior surface has been so injured by the mineralization of the test, that its characters are not determinable.
A slight carina is preserved on the cast of the dorsal surface. It does not appear to have any connection with the siphuncle or areola surround- ing it.
Orthoceras clinocameratum Winchell (Amer. Jour. Sci., vol. xxxiii, p. 356, 1862) is the only American species that appears to correspond to this. With the description to decide from, it does not appear that the Michigan and Nevada shells belong to one species.
Formation and locality—Lower portion of Lower Carboniferous lime- stone in canon directly south of a small conical hill on east side of Secret- canon-road Canon, Eureka District, Nevada.
Orthoceras, sp. ? A small species, with fine vertical annulations, is associated with 0.
Eurekensis. It appears to be slightly curved, and to have its cone enlarg- ing gradually and uniformly.
PCECILOPODA. Genus GRIFFITHIDES Portlock.
Griffithides Portlocki M. & W. Plate xxiv, figs. 4, 4a, b.
Phillipsia (@riffithides) Portlocki Meek & Worthen, 1865. Proc. Acad. Nat. Sci. Philad., vol: xvii, p. 268. Ibid., 1873. Geol. Surv. Illinois, vol. v, p. 525, pl. xix, fig. 6. The detailed and elaborate description given of this species by its authors provides the means for a close comparison between it and the Ne- vada specimens.
FOSSILS OF THE CARBONIFEROUS. 267
The most striking difference is the greater strength of the postero-lateral spine of the free cheek in the Nevada form. This, however, is scarcely a specific variation, and the other variations are not of specific value.
Judging from the external features of the head, this species may be re- ferred to the genus Griffithides. In the cast traces of two anterior pairs of glabellar furrows appear, but these are not seen on the outer surface of the shell. Again, the form of the glabella is that of the typical forms of Grittithides.
Of the nineteen species referred to the genus Phillipsia, from American Paleozoic strata, I do not know of one that would not admit of question. Eight are founded on specimens of the pygidium alone, and the generic reference is consequently questionable. One species, Phillipsia Lodiensis Meek (Pal. Ohio, vol. ii, p. 323, plate xviii, fig. 3), is, as suggested by Mr. Meek, referable to the genus Proetus or a subgenus of Proetus, and in this same list may be included the two Devonian species (ante p. 211 and Pal. N. Y., Illustrations of Devonian Fossils, plate xxi, hie, 29, Ps levis). OF the species left, none appear to possess the typical features of Phillipsia, but on the contrary are more nearly allied to Griffithides.
Formation and locality—Lower portion of Lower Carboniferous lime- stone, in cation directly south of a small conical hill on east side of Secret- canon-road Cation, Eureka District, Nevada.
268
PALEONTOLOGY OF THE EUREKA DISTRICT.
SYSTEMATIC LIST OF FOSSILS OF EACH GEOLOGIC FORMATION.
CAMBRIAN.
PROSPECT MOUNTAIN GROUP.
(The double multiple (x x) denotes that the species passes to the group above.]
Genera and species. s E =] PORIFERA. Protospongia fenestrata Salter ..-..... x JiR) hoods tooo Saeasess Sore cro BRACHIOPODA. LU HES th 53h oe sa sor ceeocaossaceas x Lingulepis Mera H. &W.......-...--- xX ? minuta H. &W ..-.---.-.- xx Lingula ? manticula White .........-.. xX Obolella discoidea H. & W .--..--..--- xX Gib Hesshot resseniie -poesccncne x Acrothele ? dichotoma, n. sp. ?.---.----- x Acrotreta gemma Billings.....-..-.-.. xX Kutorgina Prospectensis, n. sp---.----- Xx sculptilis Meek ........---- x Whitfieldi, n. sp -....-..---- oe Leptena Melita H. & W....-..-.-..-.- DOO Orthis Eurekensis, n. sp. --------------- Xe Rie t) eencechecheebeceanonsecsdenoy x PTEROPODA. Stenotheca elongata, n. sp.--..--.. Jeet < Hyolithes primordialis Hall (sp.) .....- x Scenella ? conula,n. sp.-..-------------- PECILOPODA. Agnostus bidens Meek ...........---.. communis H. & W. Neon H. & W......
prolongus H. & W . Richmondensis, n. sp
seclusus, I. sp.----- Olenellus Gilberti Meek Howelli Meek. Iddingsi, n. sp Dicellocephalus ? angustifrons, n. sp... bilobatus H. & W ..
? expansus, n.sp . flabellifer H. & WW
Tole, n. sp. Marica, n. s) - nasutus, 0. sp. Osceola Hall ? quadriceps H. & W.. Richmondensis, n. sp-.
White Pine.
Remarks. Type from the Cambrian of Wales.....-...-........---.-- Fragment........... SERRE DAAC OUSOmOOCacKOTEeSoE ES Sceoee
Types from Eureka and White Pine Districts, Nevada -.. Type from the Eureka District
Type from Schell Creek Range, Nevada .-....-..........- Type from Eureka District...-...-.--...----------------- Like O. pretiosa Billings........-..- eoscaskenee) fone sacle
Type from Pioche, Nevada. .
Type from Eureka District
Geol. Expl. Fortieth Parallel, vol. iv, p. 227.
Type from the Potsdam sandstone of Wisconsin.-.-.....-.. Type from Ute Peak, Wahsatch Range, Utah..........-.-
Page.
SYSTEMATIC LIST. 269
CAMBRIA N—Continued. Sint el a Genera and species. | 2 Remarks. Page. E = i) e Ptychoparia (?) angulatus H. & W.....|...--... oN Geol. Expl. Fortieth Parallel, vol. iv, p. 220 .............---|...-...- Anytus H. & W .....-.--- SS WEsGorness Type from Schell Creek, Nevada.....................-.2-- 56 (S.) breviceps, n. sp..--.-- ee [be seqoso| HeSeSSc ernst oceans cocs Had SEC R ROS See RS SSOS SAGES 49 granulosus H. & W..--.--. ee essence ‘Lypetrom'Kurcka Districts... -.o-coescowocesce-=cesees 7 Haguei H. & W. (sp.)----- SOG been ase Type from the White Pine District, Nevada 57 lawviceps, n. sp ---------.-- ee | Beeeesos Senne meme emnlpw ae =nivemncrleewsinclewme accuses cvmacise=seasciccs 54 (2?) Linnarseoni, n. sp-.--.. o< 47 maculosus H. & W. (sp.)--| XX |.-.----- Geol. Expl. Fortieth Par., vol. iv, p.215 ..............--..- Jeneeeeee nitidus H. & W. (sp.) -.---| = -| Type from Eureka District | 57 occidentalis, n. sp .-.-.- -- So) lee =| pac COSC ER coboe nee eetO esse Stars SEB Seace Cos roceensesenos | 51 Oweni M. & H. (sp.) .- XX |..--.---.| Type from Big Horn Mountains, Montana.............-.. | 55 (2) pernasutus, m sp -- bya | [ee B | Reeereaece am an nomen seen es Rene ae ence me ene | 49 (2) Prospectensis, n. sp.--. x — solockeascboccosatccont Gocccpos Scecoes sso fbomsaso SaSsesossec5 46 (2) similis, n. sp ..-----.-.. Be Ui beeces acl Se ose coSsbocesseicc aces bose Sa OSS ScOCeEeoat ae ep Case mcaeene 62 (?)similis, var. robustus, n. SC eerie | sii nae ee motel ie et tenn neeleie Sens oneal aac eee ea 53 var. unisuleatus H. & W .--...- Ba Nhossenee Type from Eureka District ....-.......----.------------<- 58 (earelornee 1) elise TST ee | eo ce een aerate ae nea ah cen eae nace cneh else asie om s=eieo meee 54 (Euloma?) dissimilis,m:sp.| X< |---.--..|---..-----s--e--<-- ae 5 i Nt Se i SS ei a os ee 51 (P.) laticeps H.& W...---. be Be eae Type from White Pine District, Nevada......-........... 59 (P.) occidens, nm sp. .------ | eictetetteas | ees ie men ated aimnreiciniclnnninlelwnie me meme eine elmo eieainie nite aioe 58 BY eosoconcesas Seb one secu Koecoces Bs | Re eR Gorge eee Cece Cop een terror eSoereS= snes CCS SSeS ecease Me sSoC oo Anomocare ? parvum, N. sp.------------ Sign [See oe oe | easy hee he baton ee et . 2e co choo cased teacarat. toe 59 Ptychaspis minuta Whitfield.......... Xa eae ate=2 Type from the Potsdam sandstone of Wisconsin........... 60 pustulosa H. & W ....--.--|.--..... L. Geol. Expl. Fortieth Par., vol. iv, p. 223-...-..-..----...... tentsanne Chariocephalus ? tumifrons H. & W..| xX L. Type from the White Pine District, Nevada.............- 61 Agraulos ? globosus, nD. Sp .----------. - Mo [ewe nee ee] ene eee eee ee eee ee ee ee een ee ees ee eee cee ee eee eee 61 Arethusina Americana, n. sp.-----.---- OO, acess nas] bos cStesqs sates ise sce oSscor ber Se Saccina ss Saosries eps acess 62 Ogygia ? problematica, n.sp-.-----.--.-| XX © |--------|------------------- fannie anaes meena nner mnoneeincatessee= 63 ? spinosa, 0. Sp .-...------------ S| aoe ea sane == ms we nial wise'e em nen a ns eele eee ae 63 TUTE U 1b boos sesoncscaseeasced paeoccon Be Sromcaosesses reese Peer
16 The species from the White Pine District occur at the base of the Pogonip Group and are doubtfully referred to the Cambrian.
270 PALEONTOLOGY OF THE EUREKA DISTRICT.
LOWER SILURIAN.
POGONIP GROUP.
[The letter C in the first column denotes that the species also occurs in the Cambrian.]
5 a KE tig & | a |AS ° a ok Genera and species. Al | Fie) Remarks. Page. é d = g\2 | 83 5 | 3/2 Qa | a |e RHIZOPODA. Receptaculites ellipticus, n. sp -----------|------ elongatus, 0. Sp.--.-------|------ a mammillaris Newberry --|..---- x HYDROZOA. Graptolithus, sp. ?..------------+++--++++-|e----- x ACTINOZOA. Monticulopora, sp ?.--..----------+-++-+++|------ > an PEPE eee errr rrr rt reer tere rr errr err tnnn Crernn 60 POLYZOA. Ptilodictya, sp. ?..----------- ---+++---0+-|------ 5 ane Be Serre eee eee eS eee eee Gecnonoy brsessece BRACHIOPODA. Lingulepis Mera H. & W ..-..----.------ (Ob. | Bseeeel|Eeasse Types from the Eureka and White Pine Districts, 12 Nevada. - {minuta H. & W..-..----.---- O) NWeeassdbecoss Type from Eureka District....-....---.------------ 13 Lingula ? manticula White.----.--------- (Ch bae=cel|hasons Type from the Schell Creek Range, Nevada. .......- 13 Lingula sp? ..-------------+----++++++++-[-eeee-]eeeee 00 | pecontmertecececenootacnds cas cacn sneer corearecstesnas.| Peoseosts Obolella ? ambigua, n. sp - - K |e ee eee) owen ee] ee ee ee eee cee ee eee ee cee ne cee ee coe ee ene ee cee e ee 67 discoidea H. & W-- Cc. L. | Type from Eureka District ...........-.-..-----.--- 14 Acrotreta gemma!’ Billings.- Type from Calciferous Formation of Newfoundland. 17 sp. 1 ....--------- .| Like A. subconica Kutorga.....--..----------------|--------- Schizambon typicalis, n. sp...------------| XK |------|-eeee- esse eee eee ce eee eee es cee eee e ees eee ee eee eee ee este ee: 70 Leptena melita H. & W..-.- Type from Eureka District ......-...--...-..--.---- 22 Strophomena Nemea H. & W. Type from White Pine District, Nevada..... seuss 71 Orthis Hamburgensis, n. sp -- Rec Hao ae SBC Se CUS neEEo Seon Son aacoecdas hoe seserecans 73 Lonensi8, 0. 8p --------------0-2--cfemmena| XK [oneene|one- ee ence nnn neem en enn mre enn mmm enmmcrecercennens 74 perveta Conrad ... Trenton of Wisconsin, Chazy of Canada, eto.-......- 72 Pogonipensis H. & W..-.-...--- Geol. Expl. Fortieth Par., vol. iv, p. 232.......--.---- Lae eanes testudinaria Dalman.-....-------.]------ Trenton Group species of New York, Canada, etc... 72 tricenaria Conrad..........--.-..-|------ Trenton Group species of New York, Canada, etc.. 74 SP. 9 - 2-2-2 cen n ee ene cee ene cee een eens K acecen|ocescn|eccc cc cece cw cncc ee cncenes cate cere ce ceme enna nner nemnnnelorrennsen Fy en] prose spaeene bbs -Obeaeeseseeee] Feeses|| 4 ||) Wb | Poooococeocmocesaooe on Socoe Sabedd sac ac acm os cea t| en ae =a Streptorhynchus minor, n.8P.--..-------|--e0--] XX fesenes [ee neeeeee cece cece teeter etter cette ere cer ee reeee es 75 Porambonites obscurus H. & W.....-----|------|------]-- .| Geol. Expl. Fortieth Par., vol. iv, p. 234.........-----|.-----+-- Triplesia calcifera Billings...-.---------- x Calciferous formation of Canada*.....-.----.--..--- 75 LAMFELLIBRANCHIATA. Tellinomya contracta Salter?..-...------].----- x Uz ? Hamburgensis, 0. Sp --.---.-|------ SM | pees secon neem nh nen enn nemecueleenee Modiolopsis occidens, n. sp.-.------------|------ x Uz. Pogonipensis, 0. sp..-..-----|------ x 106 SDP. Pon - onan c naw s cen nwennen=[aue === |ennm a= U.
17 Identified by Mr. Meek from Malade City, Utah. Hayden’s Report for 1872, p. 464.
SYSTEMATIC LIST.
LOWER SILURIA N—Continued.
271
S ¢]¢|'. |e | ee Genera and species. al a B 5 Remarks. Page. g| 4/33 BE \2° AH | ATE i} \ — — —E GASTEROPODA. Bellerophon (Bucania) bidorsata Hall....)...-..|...--- U. | Trenton Group species in New York, Canada, etc..|......... Glib sen seadusscnsp soseenocad pooscr >S) |Eosae Like B. allegoricus White Strapanoiusispatiasosne tee schesecae-seae |cscees|eecee WJea eetciaretteatminkite a osiecena ciate an ctetadas are sree oe ele Raphistoma Nasoni Hall (sp.). Trenton Group of Wisconsin RUSE cz ens cee acoteaspe oa ore Reson’ | WES | cater! Hao SSeS cece Senco SCLCO SoH ee re= ae nae Murchisonia Milleri Hall. . Trenton Group species in New York, Canada, etc 79 RY bY conocecodoscancecoscoond ened oS | boson) boSsabe ce toscedsconsclacebasseosece SSnScoeseiasscese|) Soaaeene (TES Gconepe cr apse sees iee cal cca) Heceos ei Renee eee ane ine nera rans acntd reece nee esetern aa? [hmeaee ce Pleurotomaria Lonensis, n. sp ...-...-... |------ x Wh. | pesaqeetncoga so aoc CABO SODA DEBE COSHOScaceuC HOA sas 80 ADS ase ceca ne sion] sacs os) ececon barstsoscho sabaomaans chdsaassees soc mG HDA RUCODCABOESH HoaRares § HelicolLomaySPetecac ae Je -manleoeoeieneee= | eamiaen Ot bgeesal ME seaa cap soo Cosco ISO TEOOSEC DOSE AAR ece Ssecornroncos 81 Maclurea anrulata, n. sp ..-..... .--.---.|-----+ x WG: | GecetecnacoScGec poco ane sc aa EEoHaFoOEoE Seno ecSoSE aon | 81 carinats, N: Sp)<--<0.--------->-|===4-~ PS) A backed bcoSSseab SpaSncr Dae SAHA RC OSOB A EOE Be ae oae ee | 82 subannulata, n. sp ..-......--..|------ OS | ose paccasSsoeson ner GSS5oS SaaSRCRSEE EOS Gocerbsbochonsnoes j@ 982 RUE) soe ceta seaassmeadassoseene Pesces OEE | ena weer sae aie laine lam erin leeaae ae eerie ease ceisin ciccinceee 83 Metoptoma ? analoga, n. sp....--..-----.--|------|------ US eae soe eemen ten cect eee ce eas seen s mecca meee ; 84 Phillipsi;msspsassess=--eesece [ns -oe-|eceaee Wave |P- sececsecasccaccscussstcs coat sens cacueeene anemic es | (9g Cyrtolites sinuatus H. & W..............|------ Bg [Repos Type from the White Pine District, Nevada ........ eee é PTEROPODA,. Coleoprion minuta, n. sp......-..-.--.---.|------ x 1b) | Kocnotseq eq ae snes nt conc assoc AABe CSC anEEeoocdsee 85 Hyolithes Vanuxemi, n. sp ......-....-...|------ Dy loasduc booctBoHsnd tecostesedcaasoncabocstEosmoree seascuchess 85 GDH boa sac coesecdasanosneasare ce HaSaes|[Scaso> NU otela te ee a are eee ne anes Roe eee Se eee JpSencecce CEPHALOPODA. Orthoceras multicameratum Hall ........|------ x U. | A species of the Lower Trenton in New York.....- 86 Zi oh opens eee es eer ere aease Nene [alles ne Soytyns See ein een he et Ba ee 86, 87 Endoceras (like E. multitubulatum)......)------ oe Reece Species of Lower Trenton in New York State ...... 87 proteiforme Hall..............|------ ean lee oral Trenton Group species............--..-------------- 86 CRUSTACEA. : Leperditia bivia White ...........-....-. ig eee Type from the Schell Creek Range, Nevada ......-. 88 ist} eos x 88 BSyrichinv Sp: teen asses saseeeee eee ees x 88 PPIUMUItESs aD he secre tase ele oisata sale ala Xx 88 PCCILOPODA. Agnostus communis H. & W ....... mccoee Cm. | ScAoa| Eascas Type from White Pine District, Nevada ..........--) 27 tumidosus H. & W..........--- SxS ijncoccs| seed Geol. Expl. Fortieth Par., vol. iv. p.281.---....--.---|....-.2-. Dicellocephalus inexpectans, n. sp...-.--. »S, | oeSooc| Reetod memos am eSescecascoceotonodt cose Gace ORCP aR eSess 90 finalis, n.sp .....-.. Shded basses Dot bnoecs hastodas .o¢s, Bosns esas Seca pseasce Ose SuSSSe ne paan ee 89 multicinctus H. & W....| X |------|...-.. Geol. Expl. Fortieth Par., vol. iv, p. 226..-.........-- |Sseeaaewe Ptycoparia annectans, n.sp ....--..----- 2S |e goo) Aooens| bSeosest orqco ese scdek ses ocr Sc osQNenoDESE Se coSeHDbOSae | 91 granulosus H. & W.(sp.)----. (Ch Ne ecase booaed Type from Eureka District... ........---...------- | 57 Haguei H. & W.(sp.)- Pesccse|) (A NeeESos|esscen Type from the White Pine District..............--. 57 maculosus H. & W.(sp.). ---.| C. |..----|------ Geol. Expl. Fortieth Par., vol. iv, p. 215.......-----.- leacwaceee Oweni Meek........-........ G5) |kesesslbsasds Type from Big Horn Mountains, Montana .......-.. 55 INET CERCA ER TOCNY SAB Ys) tases Ore dll ecetete at nO ate nine cle Giwin'e «wets mane a)ata mae cls ow eee een ee 58 (Euloma 2) affinis, n. sp.?..... G4 | kasocc 1S bososincke codec ess SenSho Scns eeeeconeeapeeec HOES eHee 54
D2 PALEONTOLOGY OF THE EUREKA DISTRICT.
LOWER SILURIAN—Continued.
5 B i] e | & 6 a Genera and species. RA | PR S os culae 5 I R i) Arethusina Americana, 0D. 8p..----------- C.
Bathyurus ? congeneris, n. sp.- Pogonipensis H. & W .- ? simillimus, n. sp.......----- ? tuberculatus, n. sp .---.--- Se
Cyphaspis ? brevimarginatus, n. sp---..-- Amphion Nevadensis, n. sp.---..---------
GTAUIUS ADs tessa eee setae eee anaes Symphysurus ? Goldfussi, n. sp ..-------- Barrandia ? McCoyi, n. sp ---.------------
Tilenufus Eurekensis, n.sp-.-..-. -----.
Tilenus crassicauda Wahlenborg (sp.) -- IE becom saamee tn acc non noeccencc Asaphus Caribouensis, n. sp .--. --------- ? curiosus Billings..-..--..-----
White Pine, Lower and Upper.
Page.
SYSTEMATIO LIST. 273
LONE MOUNTAIN SILURIAN.
5 . } Genera and species. 5 3 5 g 2 Remarks. Page. tae fay [se Si (Pence ACTINOZOA. Streptelaama, n- sp...-.......-..--s..<0- GEN eames | heetas | ee cbne trees coe hana conan ae eee we Sean ae tenser tana | pence cae dlejbal ledcossechec cen eceososed Bre esate) eecic] og ec Ose SSeS oo See Cease gece Coo Seas ecacetedoenseced Meese AAPHTEMtIB\ Spe fem ee iaacs ale cnsemeecclocmcne Be leresea| bt doec ac tacotc sac ce CCR REL IGE P EC COSMO ADEE POCO eee See] Maan mers Halysites catenulatus Linn (sp.)..-..-.-.|.----- x Lig | te Soa senses SagsccnecBenceesc aos nen eo Peco bnesar sateen) baereesse Monticulopora, sp. %..........-.--20.2--- D6 heesee|bonece leseeos coco conce eee Sec Esa Dusen boesasbeoEanaceos| Heraasssa ECHINODERMATA. yah ceo sn eee beeeaanescenresacsmnwss- DN 6 aol PArOSS RE DELNLG DIRLON coon a deena cn on ncessaneene sn oealoemcs se ¢ BRACHIOPODA. Leptena sericea Sowerby x Orth nian an aces eeoeeee ae ees eaace x a CEPHALOPODA. Orthooeras SDuli-css. cee ceder aces qoseae Be SecA loonie el Pa ceoct asec scab acca ce S CHO SON rOaHE eee aeacca aed basses Cyntoceraans Dp. see senen on seei case tees ae Ee | oa cens | -eeaee tee neneaneen state saan sate cnnatencene sar aas saeco aaa | Comoe setae PCCILOPODA.
18 CD W
274 PALEONTOLOGY OF THE EUREKA DISTRICT.
DEVONIAN.
ABBREVIATIONS.—Up. Held.= Upper Helderberg. Ham.=Hamilton Group Ch.=Chemung Group of the Devonian series of the Geological Survey of New York. H. & W.=Hall & Whitfield, Geol. Expl. Fortieth Parallel, vol. iv, 1877.
S A 2 . |As Genera and species. 8 Fie SFE Remarks. Page. E| = |26 SSE PORIFERA. Palzomanon Roemeri, n. 8p.-.----------- 54) [bse] |aassod nerenaiasnon adseeocs SodcriceotoonsosdcedHosdocr dap on6 99 Astylospongia, sp. ? ----- HK eww ewe leew nnn leccn em ccwc nc cc cc nce nenen camnnn cnncsesncesernarcencneas 99 Stromatopora, sp. ? ..--.-....---------- x BS \ecsee)| soocanosonccec sone coo ons SoSactosdaropdsatacocnccieosact 100 ACTINOZOA. Fistulipora, sp.?.....---. easel] XM) maces | awec ci] cocneen «nn en mene em cine = mem aon oe nies pinemamnanie onainenleininn 101 Favosites hemispherica, Y. & S.....-.--- $e eee! |seonae Up. Held. and Ham. of New York and Canada; Up. 100 Held. Falls of Ohio. basaltica, var.---.--..--..-.... 100 ) I. Sp. -.--.----------- 101 Alveolites multilamellata Meek... Geol. Expl. Fortieth Par., vol. iv, p. 25...-.----.-----|........- Rockfordensis Hall?..-. =e t Re [her ees Type from Devonian of Iowa-.-.-..-.--.---..-.---- 102 Cladopora prolifica Hall ............-----|------|------ x | Up. Held. of New York and Falls of Ohio...-.......]......... pulchra Rominger? ...-..-----|------ > leatcee Up. Held. of New York and Falls of Ohio-.....---.- 102 Fis) Un RS on Sco e ac Hee ceceae x Up. Held. of New York and Falls of Ohio-.-...-..-.. 102 Thecia ramosa Rominger? ..--..-----.--- 4 Up. Held. of New York and Falls of Ohio..-........ 102 Syringopora Hisingeri Billings..--......--|------ Up. Held. of New York and Falls of Ohio .--..-.... 103 perelegans Billings -.....-.-- | Ok |lecce nc Soooce ceooneeont conorscorecese tec ddadssessccsessesass 103 Aulopora serpens Goldfuss ..--..-..----- Oe | eeesc|lansese Hamvop MaGni PON cessnensc ese eee eee 103 Cyathophyllum corniculum M. Ed...-....|------ a | eens Up. Held. of New York, Canada, Falls of Ohio, etc. 104 Davidsoni M. Ed........ Bé |sscee- \ecbecs Hamilton of Low aas-=-ecscr <n oseeeee eee eeee 104 rugosum M.Ed. &Haime| X |------|------ Up. Held. of New York, Falls of Ohio, ete.--...---.. 104 QB) esse coserisoce i en 104 FSDediae sesena sesame Sadee | xem=m | amma 105 Acervularia pentagona Goldfuss-..-..--.]------ x x | Identified by Meek, from White Pine Dist., Nevada.| 105 Smithia Hennahii Lonsdale (sp.)-...-----|.-----|------ x | Geol. Expl. Fortieth Par., vol. iv, p. 32 ..-....-.-..--.|..-...2-- Pachyphyllam Woodmani White, sp.----|------| X |------ DS vonianl Of LO Wa eee ee eee eee 105 Diphyphyllum Simecoense M. Ed....--..- oe |laens- x | Up. Held of New York, Falls of Ohio, ete ....--.... 105 Ptychophyllum ? infundibulum Meek -..|.----.|------ | X | Geol. Expl Fortieth Par., vol. iv, p. 28 -...,..-.------|.....-.-. Cystiphyllum Americanum M, Ed....-- SO cewel|escees Up. Held. New York, Falls of Ohio, etc.; Ham. of 106 New York, etc. patho (SB eetele le wma ==] == l= Mi | cena a] oem aee| econ. cece ewe mene eee een weweimewn een inin wenn senmininmme 106 POLYZOA. Fenestella, 2 sp. ?.....-- 2.2.2 scene cecnees Fe Weaeree| Pasa! Poeccnen sce ssdos obo cinc Ovoboguscese aac Ossiadodadsetissaa|noetcses Mhamnisens:? Bp. %. <<. 50000. ncenancunens SCUN eae melee Fee Sok Scns cintarteatet et enn oat sito wale s ae re eine sinless sepa imine eee eat BRACHIOPODA. Lingula Alba-pinensis, n. sp.-.-..--..--.|.-----|.----- 3) miseries nobae Hanb Asoo soon Cae eG ekse re tece dees 108 Lipsiig st Seon cccs osreb Ham. Group Of NGWw M0tka = 2. seap essere sen a eeel ne 106 Ligea Hall.. Ham. Group of New York.. ......--..-....-..-.--- 107 Ligea, var. Nevadensis, n. var....|...-.. De ee al Bea sei ocer o> Ge G ane COO RECOUNT De SS OnEOA SSIS 107 Lonensis, 0. sp ...--.--.-.-- SA P's | Hessea heeeedl seat ceenee cose pe sone ee ab as coneosnormee Sermo Secs as 108 Molie) Halles. 2: cestencice scree toad Cin Case tea Pale Ne Wag VOL Vg elk ome p oeie ee sen ale rete terete | et ee Whitei, n. sp.-... 2... 22. ecceeeee] XK feeeeneleceenn|e ne cone en cece nee e teen seen ace nenrnesnmarceeeenceence 109 VSD foe aca Me ee ap amg ace oboasboncon serra oncrecsstccs eco po aaoa| Sane stetecte Discina Lodensis Hall - X | Ham. of New York ..-.....--..--... Bemoagaaccedasce 112 minuta Hall?.- Ham. of New York ......--..- Sabon colene eae see eae 112
SYSTEMATIC LIST.
275
DEVONIAN-—Continued, o d=| oe Ag Genera and species. rs Bg | om Remarks. Page. | & | zr S| (ei |e Pholidops bellula, n. sp.---.------------- &S I hscécoel Eeeaed hececRekSossin= SEE ORO pep OSe BCOpoeEECUCOCS aaerCee 1138 quadrangularis, n. sp --------- Pe essa cal BcOSon boseac nc aso s8e2 Sa Sre SACS SSE PEEP Da OaSDRCS SS ana Soaa5e 114 Orthis impressa Hall gpa Se || (GUN Ge ING YP MG a Raper esoocneccncse scone asease 115 McFarlanei Meek > | Hodese > | Type from Mackenzie River, British America --.... 114 Tulliensis Vanuxem ....-..--..-.-|------ oi | posses IPA OLONG way OL Ke eet otee ais once ak cee ene aie 115 Skenidium Devonicum, n. sp ------------ S22 | heres oee.ee| beboecessete sa: eb See nonns 2p on Dee nes ase eqeeeedoecaeeed 116 Streptorhynchu3 Chemungensis Conrad | X |..----|------ Up. Held., Ham., and Ch. of New York.....--.-----. 117 (sp.) Chemungensis, var. Pan-| X be eee 8ice Up. Held. of New York and Canada ...-..-------.--- 117 dora Billings. Chemungensis, var., per-| X_ |------|------ Up. Held. and Ham. of New York. .....-...--------- 117 versa Hall. Strophomenarhomboidalis Wilckens (sp.)| % |.-----|----- Up. Held., New York, Falls of Ohio, etc. ..-......--. 118 Strophodonta arcuata Hall...-..--.------ mS |peerice|eecee Sy OU OLELON Aiaeas pee =n anal eae reas eno 121 Calvini Miller .-...-...... DS |brctes| eases Devonian! Ofslowa)ca-- ae aeees leew nas aaa =e 122 canace H. & W.....-...-- 2 |bonSsa~ X | Geol. Expl. Fortieth Par., vol. iv, p. 246, 1877 ..--..---|...---... demissa Conrad (sp.) ------ Pree | be acta osscn Devonian of Iowa, New York, etc.; Mackenzie 118 River, B. A. inequiradiata Hall..--..-- Up. Held. of New York ....-.-..-.---.------+- es-00+ 120 Patersoni Hall.....----.-- Up. Held. of New York - 119 perplana Conrad, (sp.)----.- Throughout the Devonian of New York.....-- ---- 120 punctulifera Conrad (sp.) - Throughout the Devonian of New York.-.-......--. 121 Chonetes deflecta Hall .......-..--.------ a PELAITIAOL SNOWY ON Kae senate nanan = eee een 124 filistriata, n. Sp ---------cs----.] 2 |------|-----=|-.- ~~ 5-- = =o = ~- ===> 127 hemispherica Hall .......-..--. Up. Held: of New York ..--:.-...--:-..-.<..-------- 123 macrostriata, D..Sp----------c0=| X | e-----|---- 22] 0-20 eee nee enna nen en nn nee en mn nnns connne cacnestecnes 126 mucronata Hall.....-.--------- Up. Held. of New York, etc.; Great Bear Lake, B.A.) 124 Setigera Hall ....-...-...-..... Ham. of New York, ete .......-......--------------- 125 RB Dail eens sateen an faces en a| em mmm |e ee OG | Cerna ine we tare ene nine wnmls alam mtn slow o's sinini= ain aisininln wrininen =n |sclsine sam Productus (P.) Hallanus, n. sp.-.--------- oS Sa lanaee Mevonian ObMOw see ssarn cae coeeenere estas eee 130 (P.) hirsutiforme, n.sp..-..--.]------].----- SCR | Renee te nrye en tae es Some onsen eat aoa aee 133 (P.) lachrymosus Conrad (sp.) |------ S| SeSabel | peas s Sceencsosse seoscecondoseriseogaoc Usa o saa eaceae 132 (P.) lacbrymosus, var., limus |.----- Mey Waesioce ClinoteNewaVOtkoa ec msisncsee ancients antec eeemenanecs 132 Conrad (sp.) (P.) lachrymosus, var., stig- |------ <8 lbacisd OhvoreNewe Col ks-ses ean aeeaeaaiess essa naneeen se 132 matus Hall. (P.) navicellus Hall. ...--...--. Se Noceoss| Eocab = Up. Held. and Ham. of New York.........---.------ 131 (P.) Shumardianus Hall....... x X |s--2s- Devonian OlMOWAeemcees cea meee eames see 129 (P.) Shumardianns, var., pyx- | X Me. [eansae DOONAN OD LOW Wass scene eee eae anes eee 129 idatus Hall. ((2)ispeciosns Mall s2--.--.-..|--~--~ >< |oonacn Chote News COU be ones a ee Saore een atecee ns 133 (P.) sabaculeatus Murch. x x x ~| Up. Held. Falls of Ohio ..-...-..--.---..----.------ 128 (P.) truncatus Hall .... HamvoreNe ws Vonks cccsenese ss che aencpta neo cepiten 131 (aot dea sen es SSasoeso Of the type of P. semireticulatus -.--...-..--.-- Pye5) (io, ceases Spirifera Alba-pinensis H. & W. Geol. Expl. Fortieth Par., vol. iv, p. 255.....-.------.].-------+ digjunctaSowerby.........-----|.-..-- x | Ch.of New York, Mackensie River, B, A., etc-.-..-. 134 Englemanni Meek?.....-....-..|.----- oe x | Type, Eureka and White Pine Districts, Nevada....| 138 Parryana Hall ?....- X |------|------ Devonian of Iowa and Canada ........-..--..--.---- 137 Pifionensis Meek....-.-.. x oc Xx | Type, Pinon Range, Nevada......-..--. oncacctscods 138 raricosta Conrad, (sp.) -.------- x Up. Held. of New York, Falls of Ohio, ete.---...-- 135 strigosus Meek.......-.........|---..-- Geol. Expl. Fortieth Par., vol. iv, p. 43... Lesenecod Spirifera varicosa Hall..-...... Saaeecacsee x Up. Held. of New York, Falls of Ohio, ete 136 Sp. ONdbs.~<--scccenn~ possesses 2 | Beesoe [ewmecio| wees sue Cesceiecn same enmmenminmachsiannee=ccronnncen 137
276
PALEONTOLOGY OF THE EUREKA DISTRIOT.
DEVONTIAN—Continued. = a OA Sel ies See ; Ag Genera and species. B A | Sis Remarks. Page. B\ ele A =) (M.) glabra, var., Nevadensis, |------ B41 RE S504 crs. copra sasmacecenaueccce Cn) Perce rec oe ce dO> eee we 3) n. var. : (M.) Maia Billings. .....-..----- x SOFA Spee Up. Held. of New York and Canada....... aiaaseemns 141 (M.) undifera Reemer..--.------ al Resse] pemses| Peer ecccec a Gos See concaco sore a nes eC ose nooS cosensco: 143 Spiriferina cristata Schlothem (sp.)- X. | Also in Carboniferous......--.2---csce-ccnsecc-o2---| 218 Amboccelia umbonata Conrad (sp.)-- x | Ham. Group of New York .......--..----------+s2+-[-+--20+*+ Cyrtina Davidsoni, n. sp. -----------+-+-|-+--++-|------ KOS eten ce nesicelecome seawennnanac rsa anencer=haleewsae=maSna 146 Hamiltonensis Hall ..-....-.-----]------ 60) | ews | etree a cacao ne ee Sitane o sfetace ate erat tareietaa( ee rataielt ee meter 147 Nucleospira concinna Hall..-.--.. X |------]------ Up. Held. and Ham. of New York..........--- Osenc 147 Trematospira infrequens, D. Sp ----------] XK |es----|--2 22 [eee eee eee eee eee te eee nent ee newer et een re nes 151 Retzia radialis Phillips (sp.) -| X | Also in Carboniferous.........-.-....-.---00 Pron abad 220 Athyris Angelica Hall....---.--..-----+-|----+- X |----- Ch. of New York -..-..-.---.-..-« =Spqoane rescsno- 148 pagent eceee er Of the type of Athyris plano-sulcata .......--------|--------- sp. ?... se ahets soe 0 eee Bema ee et Senet an nase Sa esses oOnC Oke snoop aero Scir 3 148 Meristella (W.) nasuta Conrad (sp.) - x Up. Held. of New York....-...----. .cscesensse==--- 148 Atrypa desquamata Sowerby. .--..--.---- x Devonian of England......-.-...----..---.. sorccess 150 reticularis Linn, (sp.).-----.----- x x X | Devonian of America, Europe, eto......-....------- 150 Rhynchonella castanea Meek .......-..-- x xX |------ Type from Mackenzie River, B. A......-..-.------- 153 duplicata Hall........-.-..|------ x X | Chemung ef New York.........--.... 155 Emmonsi H. & W Geol. Expl. Yortieth Par., vol. iv, p. 247 -- 157 Horsfordi Hall..-......--- Hamilton of New York....-.....--......--- 152 pugnus Martin.........--- -| Devonian of Ohio, New York, and England. 155 ? occidens, 0. Sp--.-------.] XX |enewe-) XM |---------------------- ++ 22-25 eee eee quadricosta Hall Genesee Slate of New York ........-..... Tethys Billings .....-...-. -| Up. Held. of Canada and Falls of Ohio.. (L.) Laura Billings. .-...-.. seee x Ham. of Canada and New York (L.) Nevadensis, n. sp ----- Booos|) pe) cece) sce coca cena See se Sen near SRS ceri ca Sscseosees (1..) sinuatus Hall. .-....-.|------ x Chemung of New MOrkose- ces ccrceseeessawesc= so Leptocoelia, sp. ?-.------.-----------+--= X |------|------ Not unlike L. acutiplicata Hal Pentamerus comis Owen (sp.)------------ XK | .nee-e|------ Ham. and Chemung of Iowa .-.......... venseweacced 159 Lotis, n. sp ..---.2--.222--2-|eeeees|eeneee Pe Wo see ce Sat rine eRe ne cmp Ose sere SD OSA LCOSER SEE 161 Tropidoleptus carinatus Hall .....-...... MK ecaman|pencee Found in Pifion Range, Nevada. .....-...--..------.|---+2-* S5 Cryptonella? circula, n.sp.-..------.---- 3 |OSsec0 eS) |Soosbeg sec koiscmogs sssSeonecnosaneanasaSsnenosbodess0o¢ 163 Pifonensis, n. sp.--..-------|------ org ecOsed| hea Seasceon Scousseadosaoosoco ceeroososcos Raeeeeeneaee 163 Terebratula, sp. ?..-...-.-------.------0-|se0ee-|---=-- oS Wesscccannsenecacceeh bab essoceccocatsoscececen Sereoos| Satcnsess LAMELLIBRANCHIATA, Aviculopecten? catactus Meek .......--.|-- ween] .ccn-- X | Geol. Expl. Fortieth Par., vol. iv, p. 93 ......-.....--.|------=-- Pterinopecten, sp. ?...-..-----.------e0--[-*2-"- fees | ROK | ioe cee aces alt Saeata ae eee Be eee Glyptodesma, sp. ?. -..--..---------+-22--|*20°*° Ses | ere ete ee ee Soe eee a! SonResce Pterinea Newarkensis, 0. 8p...-.-..-----|+----- Koi ea eem= | ecneeaee senha a eae an eee eae enema Seccacked 165 flabella Conrad -..--.-..---..--.- XE Sees ------| Upper Held. to Chemung of New York......-...... 165 Actinopteria Boydi Conrad (sp.).--...--. XK |-nee--|ee--e- Ham. Group of New York ...-.. srenoteeanncnc 166 Leiopteria Rafinesquii Hall..........-... X |------|------ Ham. Group of New York ..-... BESS SaCA RSC see --| 166 Leptodesma transversa 0. 8p-..--..--.--- feecre KI paeane| se newelse ee mariaciay aaa sinan= 167 Limoptera sarmenticia, n. sp---.....---.- X |------|--eee- = 167 Mytilarca dubia, n. sp -.....-.-----...20- ne | be coecl epcoed| Pee ececs 168 Chemungensis Conrad (sp.)...|------ X |------ Chemung @ 168 SD ial eawe eee mpl atenc enn a=rsies X ]------|-- BOR NSescooscdstccceSeecoosasosca= aloe semnenm (Plethomytilus) oviformis Con-- X |------ ------| Ham. Group of New York ...-.....--......--------- 169 rad (sp.). Modiomorpha altiforme, n. sp.--..--. cece] -X 169 oblonga, . Sp -.---.--..--- x 170
SYSTEMATIC LIST.
DEV ONIAN—Continued. g Se . ra B Genera and species. 5) Remarks. Page. aie Wrodromorphalobtnsay ins Sp see te eee | Caen eee eee teacmnecenesiae daenterenec Saceeaeras en as 171 Goniophora perangulata Hall -| Schoharie Grit of New York.. 171 Paleoneilo, sp. ?.........-. Nucula Rescuensis, n. sp u HEIN Set sec Soce eo eC Cogn aa eeeee
Nuculites triangulus H. & W....-...-.-..|-- Dysiactella insularis, n. sp Megambonia occidualis, n. sp..-...-...-. ENV @SSN DALVE) Ns BDe sence esse cecee sls Grammysia minor, n. sp Edmondia Pifionensis Meek Sanguinolites ? Combensis, n. sp § gracilis, n. sp .--..--.---- rigidus White & Whitfield (sp.).
tSanduskyensis Meek..... ventricosus White & Whit-
field (sp.). Conocardium Nevadensis, n.sp..... » 8p Lunulicardium fragosum Meek (sp.) .--. Paracyclas occidentalis peroccidens H. & W . Posidonomya Devonica, n. sp..-. Nes visy Mie Sp eeretetnase = = Microdon (C.) macrostriatus, n. sp Cardiomorpha Missouriensis Swallow -..]- Anadontopsis amygdaleformis, n. sp ..-. Schizodus (Cytherodon) orbicularis, n. sp- Cypricardinia indenta Conrad, (sp.)...-.
GASTEROPODA.
Platyceras carinatum, Hall....-......... 2 Neepcon| teases conicum Hall: <<..2..22...<-- i eee Perrine ‘Conradinn.sp------ ------— 4 D4 9 space estes dentalium Hall......... os PSfel| Banca aco nodosum Conrad ..-.......... ens Rees ccs =o thetiforme, n. sp.-.--.---..-..
PHStISeeall ee -ccnreseeae eee undulatum, n. sp..--...-..---
Platyostoma lineatum Conrad.........--.
SD Ae ee aes Ecculiomphalus Devonicus, n. sp Euomphalus Eurekensis, n. sp---
Pleurotomaria, sp.?.....--..------- Platyschisma? ambiguum, n. sp- ? McCoyi, n. sp.------- sp.t....-
Chemung of New York, Burlington Sandstone of 176 Iowa. (Unper:Heldvof Ohioves.atsass--<-snesises ce otseeew se 176 Chemung of New York, Burlington Sandstone of 177 Towa. eas aaee eetnel sate eee ee caer cee eee 17 Geol. Expl. Fortieth Par., vol. iv, p.92....-..-.-..---],........ SO RODE SARE LOL OO nH a> CURSO EE HOA OnE TOMER OG SOS SOR ee 178 179 178 PRE eB UR SECC RUCEY ERO ne =e 180 Geol. Expl. Fortieth Par., vol. iv, p.277.....---..----|......... Be SO ESRI 58 CoCo Sc DO OCOD ERE Ce Eon eOaE ea Ceara 180 Be | Wee mee Nome ene ter en ae eae tone oak sab wee 181 Upper Held. of New York and the Fallsof the Ohio.| 182 Up. Held. and Ham. of New York...-.... Soe GSerIEas 182 Up. Held. and Ham. of New York, and Up. Held. 182 Falls of the Ohio. Ae PED SOE Daa nO SECO I AES O OSE EC EE COC HORE GLO- peepee 182 Up» HeldlofiNews VOrk;. -=-ess6cs- scien oh ens eaone™ 182 (Up: celd- ot New) WOrKe ons. ssencenaceenea- so enee es 183
278
PALEONTOLOGY OF THE EUREKA DISTRICT.
DEV ONIA N—Continued. o ee Genera and species. B & 2 = Remarks. Page. B | & |2P A | PIE Calonema occidentalis, n. sp------------- x 189 Loxonema approximatum, n. sp.--------- x 191 Eurekensis, nD. sp .------------ x 190 nobile, n. sp .----.-----------+ x 190 ? subattenuatum Hall......-- Pas lesecco|ecoene Up. HeldSof New Work. --2-2. 22... ~-2 <== ve ame 191 (Gigpil) coeeeeee oe eeeep sce = bie eens [Ee WRN A Den eta oer Liber Wn akon ate Bod SaGoce ce 192 7) 0b) Jeet ae oor ioc eee sane oan) beecns) Beeman | esse cnet nos gccsecp sears COs ee esac SS anssenscetincs|fstos seco
Bellerophon Combsi, n. sp --------------- 4 [leno eases! PResctecneS sotccecttccse season tossesisicsics iosotice 193 Leda Hall --.........--.-----|sses=- IG | [pose Ham:of New York. <2 noo coneneseaaseso=-=sa=s==nm—s 194 Lyra Hall. .--...--.--------.|------ WE lees am Of NOW 00K sae e ees ee seeeeeee nice ames 194 Mera Hall .......---.------|------ %4 |Reccs: (Ch OL NG Way OF Bees teres eee eee 194 Neleus H. & W.....----.--- 2 | Bees X | Geol. Expl. Fortieth Par., vol. iv, p. 250 .-......-..--.|.------«- Pelops Hall ......-...-.----|------ Se eae UpaHelds of NewsWorlore: oo eeee eee eee ae 194 perplexa, n. sp..-.------.---
Scoliostoma Americana, N. 8p------------
Naticopsis (like N. equistriata)
is} uabene amen yet aso. aacecoo- re BDp Senor eee ean en eS nn
Metoptoma? Devonica, n. sp-.---.------- PTEROPODA.
Tentaculites attenuatus Hall .......----- a ae tele | eee Ham. of New York and Canada.-.......-...-.---.--. 197 bellulus Hall? ......-..----- PS |pemcra emote Ham. of New York and Canada ........... ..--..-.. 197 gracilistriatus Hall .-..-.--. KR |ens==-|--0--- Ham. of New York and Canada ...--..------.------- 196 scalariformis Hall . .- no) [Seca Assos Up: HealdiofiNew, Mork o-- ees ss saee see a= teen 197
Styliola fissurella Hall......-... Bas soScse x > | Secce Ham. of New York and Canada ......-.-----....---- 197
var. intermittens Hall. .|------ 5 All Eee noe| Ser Re oe Seine an nein ce sae ice: aananorenasschs bednceis 197
Conularia (sp.1)).-=.----------=-----------
Coleolus avis, NASP ee --s-uecen so e= ==
Hyolithes (like H. Aclis Hall) ..-....----
CEPHALOPODA,
Orthoceras (5 sp.?).----------------------
Gomphoceras suboviforme, n. sp
Cyrtoceras cessator H. & W...-...-..---
Nevadense, nD. sp ....--.------- Goniatites desideratus, n. 8p-------.----- beh aU ag ee eee nocd Rocker tence | x | Geol. Expl. Fortieth Par., vol. iv, p.279 ..------------|--------- TE ee eter les ee sicttetat alate mse orale wie mimeo tints Like (G. discoideus Hall) ...---.. achAcsacoodpocrocte| |sesassoon CRUSTACEA. Beyrichia occidentalis n. sp----.----.---- Se |e eos 55) Sacmesosec esac es godeos cea nos Reccos ce Sscceccoconcos 204 Leperditia rotundata, n. sp .....--.------ > aa (Riegel (ean ] Par RE Erie eS A on ene ie Sen aaa co Re 206 PQ@CILOPODA. Phacops rana Green (sp.) -.--..----++-+-- ie eeeeeel pe eee Up. Held. and Ham. of New York, Canada, etc. ...-.. 207 Dalmanites Meeki, n. sp ..--.-..--------- 9 | Renee Ceeeeel bor mcarce en sehen SSS acre eScee coat osnateMereseereecee 208 Cys) feet aoe ecsocetdeenoncad S| Geeeod| Ceecoe| panaceesacoccn Sadan. -Sseenoccicoe sacksossoescroscedas 210 Proetus Haldemani Hall ..-........-..----|------ aR Pe cead Han of New, MOCK aco a= scans ak semen ov eennieeseain 210 marginalis Conrad (sp.) --..--.-- BS) |[booceelhece= 5 Up. Held of New YOrK na. c<ccercneno=-) amenhinnemnins 210 5) 9 Bseonop naenceco Deo. Nat | essa Seaso th Senn asec ea os esseeseee ss icceess|[bossa8 2c Phillipsia coronata Hall? ..-.......--.-..|--.---] Mo |...-.- HamsiOf NOW MOP Ks cms. n ec eee a ra ete 211
4
SYSTEMATIC LIST.
279
CARBONIFEROUS. é| 3 Genera and species. e = Remarks. Page. R i=) RHIZOPODA. Fusilina cylindrica Fischer .--.....---.-- x nS Heer Shocce ISAS S655 ad EOE Sao ASA Dec Re SSeS BaOSAReY SEBsaase robusta Meek..-........-.------ x FOGG | Sanne ania Maleite'anidane nen nseaceaaenisdvas acute =e aateenpee dees | tae. sees PORIFERA. Stromatopora, sp.?......-...---.--..-..-- ae am eters | Coe a eettel etc feterenicicleaiats alas s ald’aiam sane sah elem ebinne eases] tee Saas ACTINOZOA. Zaphrentis, sp.? .---.----<-+.---- o2-wee-|onssee OE es emimmsen eins aiviepleis meine! suWeiss en uaiineceescacaemna casio ssacee ateaice Syringopora multattenuata? ...........-. Mol ewee'sie McChesney, sp Cheetetes3 sp.? .-..-.-------..----.----..-|------ 38 | bee kosectasSas SSS Ber Ss ecco annonce ES CoSneenogec or ROnacoLeEee ECHINODERMATA. Archeocidaris 2 sp.? .......--...---.---- OR ene ewe nels nie ae eo een Seeite soe ane ames nni eran a 212 POLYZOA. (POLY DOLANSD: tiene mccle Cneostnienenes esis ac] === === Sih] seat Caen asencouenceSsseece Ptilodictya (S.) carbonaria Meek? (S.) serrata Meek? ...........|------ STDs tenes Stanoesoceascoagoetie Fenestella 3 sp.? BRACHIOPODA. Discina connata, 0. Sp -.-....--.-.-..... Newberryi| Hall). oe. o eee nitida Phillips (sp.) -...--....... 2 RS So |S oR EOS OS ECCS OC OECL CAREER PETE ACCEL OS EC ee Een aS er orcs snec 213 Githh ses cnoserscncnadtosts b= stasaq aa eater ae ne ie in emtnrc Paleinle mn clette Lime Sis ota ee ee a meee Mee aa clo eects Lingula mytiloides Sowerby? .-.-...-.--- aS | RECS ES Het = Boon ono Sapo ph Osen see snat ocr eae oe C ese Cees ee er Paes Chonetes granulifera Owen .........-.--- Pohl Peco (UE S.\GeolkSury: Nebraska: p70 dSi2-. a9 --eeee saan = ween lsen ace Verneuiliana N. & P........--. PAS cere U.S. Geol: Sarv. Nebraska, p: 170; 1872.-.:-.-------.cesee--< Ie... cce Productus costatus Sowerby ......-.----. KN Cimatate Geol. Expl. Fortieth Par., vol. iv, p. 69, 1877.--.......-...-.-.|.....-.. elegans McCoy......-..-...--. XM |----+-|------ Sannnislnweem ccc nenneas aes aw sem/cmns's= ammonia xan n'elaininiensad |p ane aeae longispinus Sowerby..--. ---. x X | Geol. Expl. Fortieth Par., vol. iv, p. 78,1877 ......---..-..----|.------- Donen pnd, Vale MULIOALIAING) ip 6 |lweswne| ab ce cas cna sen cnw eine = monn sons ae seek wane nemceanseaneanea nape yeeeeeee &P. Nebrascensis Owen ....-....-. x x | Expl. & Surv. W. 100th Merid., vol iv, Pal., p. 116, 1875 ......|........ Prattenianus Norwood ........ x < | Geol. Expl Wortieth Par:, vol. iv, p. 72,1877 -----<-s--02.<<--.))-...<<- punctatus Martin (sp.)........|------ x | Expl. & Surv. W. 100th Merid., vol. iv, Pal., p. 114, 1875 ......|......-. semireticulatus Martin (sp.) ..| x x | Geol. Expl. Fortieth Par., vol. iv, p. 69,1877.--.--..........--|-------- subaculeatus Murch .......... X |ec-=-- Alsoun Devoninne ss see = ee con sages cae ee eae a ome ee eee 214 Strophomena rhomboidalis Linn, (sp.)....)| Streptorhynchus crenistria Phillips (sp.).| Orthis PecosiMarcon --..-.-=.+-)....2-..|---.-% xX | Expl. & Surv. W. 100th Merid., Pal., vol. iv, p. 125, 1875 ......|........ resupinata Martin (sp.)-...--.-..-| XX |------ Geol. Expl. Fortieth Par., vol. iv, p. 265, 1877..-.....-.-..---- Soe Spirifera annectans, n. sp .-------.-...-.- Ki [ewww | ion ene ve eee ene n mmm nw enews nc enon nn ccna ce ecen ae cecnccisensenas 216 camerata Mertén.......-.....-.. oS X | Geol. Expl Fortieth Par., vol. iv, p. 91, 1877.......-.--<.-----|.---.--- desiderata, n. sp).------.-----... Ps Jl Seance] heSne SA Bco cco cacehccos abe eaiot Sat CUD a SESE RECE EROS Sao Sr Roos 217 eid yisN. G4P yaa sece a sas ce Soha [see ees | dere ane eee eee talcin a er cleeween Gti sa ce cea anes 216 neglecta Hall ...-.....-..-...2.. mG [Beebo be dod cccenctscnds 5 Sa oscba5 OO CORSE ASR OAE SESS eee ons 217 Rockymoutana Marcou......... x X | Expl. & Surv. W. 100th Merid., vol. iv, Pal., p. 134, 1875.......|.....-.. Btriata Martin ,-<<-.-......--<.- og See sce Geol. Expl. Fortieth Par., vol. iv, p. 269, 1877..............--.|.--..--- trigonalis Martin (sp.)..-....... a (Peabbsl legac sson88 das. 5¢ SEH Re SOE DEBE EO SO IETN ORO PURE Bee RISE IAe 215 (Martinia) setigera Hall ........ eG lbcaces Geol. Expl. Fortieth Par., vol. iv, p. 270, 1877......-...---..-.|.-----+ .
280
PALEONTOLOGY OF THE EUREKA DISTRICT.
CARBONIFEROUS—Continued.
Genera and species.
Remarks.
Syringothyris cuspidatus Martin (sp.)--- Spiriferina cristata Schlotheim (sp.) -.--. Retzia radialis Phillips Athyris Royssii L’Eveillé (sp.) ----.----- lursuta Hall subtilita Hall (sp.).---------- Rhynchonella Eurekensis, n. sp Thera, n. sp
sp.? Camarophoria Cooperensis Shumard. - .-. Terebratula bovidens Morten hastata Sowerby
LAMELLIBRANCHIATA.
Aviculopecten affinis, n. sp
Eurekensis, n. sp.---.---- |
Haguei, n. sp peroccidens, n. sp Pintéensis, n. sp DAR) Bi aeieeconneasne
Streblopteria similis, n. sp Crenipecten Hallanus, n. sp Pterinopecten Hoosacensis, 0. 8p ---.-- = Spio, n. sp Pterinea Pintéensis, n. sp Leptodesma (2 sp. 1) Ptychopteria protoformis, n. sp.......--- Pinna consimilis, n. sp inexpectans, n. sp Myalina congeneris, n. sp Nemesis, 0. sp.--------- aaceceos Nessus, . sp --------- Modiola? Nevadensis, n. sp-..--.------.-- Modiomorpha ambigua, n. sp ? desiderata, n. sp.---. ? Pintoensis, n. sp-. Nucula insularis, n. sp levatiforme, n. sp Solenomya curta, n. sp Macrodon Hamilton» Hall truncatus, 0. sp tenuistriatus Meek & Worthen. Grammysia arcuata Conrad, (sp.).-------. Hannibalensis Shumard (sp.) Edmondia ? circularis, n. sp
Medon, n. sp Pleurophorus Meeki, n. sp Sanguiinolites Holus Hall................
? Nenia, n. sp retusus, Nl. Sp..--..... oee-- Salteri, n. sp simplex, n. sp striata, n. sp Microdon (Cypricardella) connatus, n. sp.
Davidson's Monograph Carb. Brachiopoda Also in Devonian
Geol. ILL, vol. v, p. 576, 1873 Ham. Group of New York
SYSTEMATIC LIST. 281
CARBONIFEROUS—Continued.
B B Genera and species. F e Remarks. Page. | =) Cardiola? filicostata, n. sp-..--..-.------- OE ena eee eee oes ede ea dacs caweas Cains cscssesantemeeseessesaes 251 Schizodus cuneatus Meek..-..-..-.--.--- x -| Coal Measures of Ohio... 252 curtiforme, 0. 8p ..---..---..-- x 253 deparcnushe oe neneceracicceciae x 252 Pintéensis, n. sp ...---.--.---- x 253 GASTEROPODA. Platyceras occidens, n. sp.--------------- eee eee ee eee eens do ets esas ns aeelsamnissaamcca esas aoe TENET) 308 1) Ososassdoscen seeescr Be | pegs) MS eqecn so eae ec C eR -CORC SS er Or eno aD one eoDoCe ene raee) Platyostoma inornatum, n. sp-------+---- ON pasate Eeeeeraeee eee Cok aman nie ence newts we senuem= nena m= == =s Evomphalus (S:)\subragosus M. & W...-) X |.-2-<-]- 2-2-2002 2- 2. ce ncnmneceancessenenccnccsces Loxonema bella, n.sp ..-...-------------- Sl beeoet | Senn cncnestsncheercte.coneceesascecssnesan= Macrocheilus, sp.?.........--..---...---- x Wares es Pleurotomaria Nevadensis......-..--...- oe) | escrd ssereeasos nodomarginata McChesney] X |.-----|.....----- Sh Uacsnocechemrogsosaaaosy | “Ps ROR ces osccechaasssissoe| Peso | BS) \leS-coscrdbsopececossoroseosee Naticopsis, sp. Pos. 2... 2 = seesec enenee eS) | becca Not unlike N. rana M. & W Bellerophon majuscula, n.sp..-.-.------- bs | Bedeihc| |Aedon aesee Soce osc sae ee nee BECO HP OL OLE CLE Bep Docc Dnoncrictenas textilis Hall................. £9) KeCOod| Rem eaaaenee es SCuge CERRO cc OH ar aC OSCE HOSA SCOSOOECOOECADE BDl sc cscamieawmnnicacacensssiom= XM feccese Like B, ellipticus McChesney. ......-....-220.-cececececence|-annence (itt jonneoeicescongesheeaones X |eceee- Dike i sublssvis Halles ne eee ce a cee ns thee ede raeeeaieas sence s|eaecanes Metoptoma peroccidens, 0. sp.-----.----- OS | Eceice! Kaci secenoc CSecA Boece RE CbIBneSoeEoce. EDSonCHnSHco co idcencroecd 260 Ampullaria? Powelli, n. sp..--------.---- $9) | Kecene| HSH BB oecibeachbo-o dt cadcpacicbe Coun CONC OMB OROTOnC Noe COnnoSAOB Is 261 PULMONIFERA. Zaptychius Carbonaria, n. sp..-.-.-..--.- Physa prisca, 0. 8p .---.-------------e-0e0- PTEROPODA. Conularia Missouriensis Shumard........ Hyolithes Carbonaria, n. sp---.-...-.-.... Dentalium (like D. Primariam) Hall ..... CEPHALOPODA. Orthoceras Eurekensis, n. sp ------------- Randolphensis Worthen...... (GSP) Peewee ceccdeencciesacen Gomphoceras, sp........-.-----seseeee-- Nautilus (like N. digonis M. & W.) ...--. CRUSTACEA. Meperditiny Gps. -<ccenonciceseenecaes == P@CILOPODA. Griffithides Portlocki M. & W. (sp.) ----- Be | eedaca Jatoccoessceor PEEL ste anesGununaunsenseacussnana crrieseracdssace 266
PALEOZOIC SECTION IN CENTRAL NEVADA.
The geologic portion of the accompanying section is taken from the “Abstract of Report on the Geology of the Eureka District, Nevada, by Arnold Hague,” contained in the Third Annual Report of the Director of the United States Geological Survey, p. 253. It is introduced to enable the student at a glance to locate in the geologic section the position of any portion of the Paleozoic fauna described in the preceding list.
All of the Cambrian fauna is included under the head of ‘“ Prospect Mountain Group,” in the systematic list.
The Lower Silurian includes the fauna of the Pogonip limestone and the base of the Lone Mountain limestone, only two or three species of corals indicating the presence of an Upper Silurian fauna.
The Devonian limestones are highly fossiliferous throughout. The fauna is best preserved within 500 feet of the base and summit, the massive beds of the central portions yielding but very few good specimens.
The White Pine shales in the Eureka District gave but two identified species and fragments of ten others referred to genera. In the White Pine District the fauna is scattered through the shale and embraces fourteen named species and eleven referred to genera.
The large fauna of the Lower Carboniferous occurs within a range of 500 feet above the summit of the Diamond Peak quartzite. Only 24 of the 132 species of the Carboniferous fauna occur above that horizon, and of
these 10 are present in the lower beds. 283
284
PALEONTOLOGY OF THE EUREKA DISTRICT.
Paleozoic section of Nevada,
Upper Carboniferous .....-...-. 500 | Light-colored blue and drab limestones .......-.--....--..------..----+.---- Weber conglomerate ........-- 2,000 | Coarse and fine conglomerates; layers of reddish yellow sandstone......... Lower Carboniferous ...---..... 8,800 | Heavy-bedded dark blue and gray limestone, with intercalated bands of
CARBONIFEROUS, 9,300 feet.
White pine shale
chert; argillaceous beds near the base.
8,000 | Massive gray and brown quartzite, with brown and green shales at the summit. The quartzite is largely a fine quartzitic conglomerate formed
of small, dark jaspery pebbles and light quartz pebbles in a grayish matrix.
2,000 | Black argillaceous shales, more or less arenaceous, with intercalations of red, and reddish brown friable sandstone, changing rapidly with the
locality; plant impressions.
Nevada limestone
DEVONIAN, 8,000 feet.
+
Lone Mountain limestone
6, 000
Ore Lower horizons indistinctly bedded, saccharoidal texture, gray color, pass- ing up into strata distinctly bedded, brown, reddish-brown and gray in color, frequently finely striped, producing a variegated appearance. The upper horizons are massive, well-bedded, and pluish-b ack in color; highly fossitiferous.
Black, gritty beds at the base, passing into a light gray siliceous rock, with all traces of bedding obliterated; Trenton fossils at the base; Halysites in the lower portion.
Eureka quartzite
Compact vitreous quartzite, white, blue, passing into reddish tints near the base; indistinct bedding.
500
Pogonip l'mestone
SILURIAN, 5,000 feet.
=) ] Vellow argillaceous shale, layers of chert nodules throughout the bed, but
Hamburg shale
2,700
Interstratified limestone, argillites, and arenaceous beds at the base, passing into purer, fine-grained limestone of a bluish gray color, distinctly bedded ; highly fossiliferous.
ow argillaceous shale, layers of chert nodules throughout the bed, bu
t more abundant near the top.
330
Hamburg limestone
1,200 | Dark gray and granular limestone; surface weathering, rough and ragged;
only slight traces of bedding.
Secret Cafion shale
1,600 | Yellow and gray argillaceous shales, passing into shaly limestone; near the
top, interstratified layers of shale and thinly bedded limestones.
CAMBRIAN, 7,700.
| Prospect Mountain limestone. . . 3, 050
Gray, compact limestone; lighter in color than the Hamburgh limestone, traversed with thin seams of calcite; bedding planes very imperfect.
Prospect Mountain
Bedded brownish white quartzites, weathering dark brown; ferruginous near the base; intercalated thin layers of arenaceous shales; beds whiter near the summit.
quartzite ...| 1,500
Nortr.—Plane of unconformity indicated by double dividing line.
PALEOZOIO SECTION. 285
Vertical range of genera.
Upper Carboniferous genera: Fusilina, Zaphrentis, Polypora, Ptylodictya, Chetetes, Orthis, Productus, Spirifera, piriferina, Retzia, Athyris, Terebratula, Myalina, Macrodon, i eaInaetoe :
Non-fossiliferons.
Lower Carboniferous genera: Fusilina, Stromatopora, Syringopora, Polypora, Ptilodictya, Fenestella, Archocidaris, Lingnla, Discina, Streptorhynchus, Orthis, Chonetes, Productus, Strophomena, Spirifera, Syringothyris, Spiriferina, Athyris, Rynchonella, Camarophoria, Terebratula, Aviculopecten, Streblopteria, Crenipecten, Pterinopecten, Pteri- nea, Leptodesma, Ptychopteria, Pinna, Myalina, Modiola, Modiomorpha, Nucula, Solenomya, Macrodon, Grammy- sia, Edmondia, Pleurophorus, Sanguinolités, Microdon, Cardiola, Schizodus, Platyceras, Platyostoma, Bellerophon, Enuomphalus, Loxonema, Macrocheilus, Pleurotomaria, Naticopsis, Metoptoma, Hyolithes, Dentalium, Conularia, Orth- oceras, Gomphoceras, Nautilus, Leperditia, Griflithides.
Productus and Athyris alone observed in a calcareous stratum near the base of the conglomerate beds, not over 200 feet above the White Pine shale.
a rc a RS
Fauna mostly in central and upper portion: Cyathophyllum, Fenestella, Lingnla, Discina, Orthis, Chonetes, Productus,
Spirifera, Amboceelia, Retzia, Athyris, Rhynchonella, Avicuiopecten, Modiomorpha, Paleoneilo, Nuculites, Cardio- morpha, Lunulicardium, Cypricardinia, Conocardium, Hyolithes, Pleurotomaria, Goniatites, Cyrtoceras, Proetus.
Upper 500 feet: Stromatopora, Alveolites, Cladopora, Syringopora, Cyathophyllum, Pachyphyllum, Lingula, Discina, Orthis, Streptorhynchus, Strophodonta, Chonetes, Productus, Spirifera, Athyris, Atrypa, Rhynchonella, Cryptonella, Pterinea, Leptodesma, Mytilarca, Nucula, Nyassa, Grammysia, Sanguinolites, Paracyclas, Enomphalus, Straparollus, Platyschisma, Bellerophon, Naticopsis, Styliola, Coleolus, Gomphoceras, Proetus, Phillipsia?.
Lower 500 fect: Palaomanon, Astylospongia, Stromatopora, Favosites, Thecia, Syringopora, Aulopora, Cyathophyllum, Acervularia, Diphyphyllum, Cystiphyllum, Lingula, Discina, Pholidops, Orthis, Skenidiam, Streptorhynchus, Stropho- mena, Strophodonta, Chonetes, Prodactus, Spirifera, Trematospira, Nucleospira, Meristella, Atrypa, Rhynchonella, Pentamerns, Cryptonella, Glyptodesma, Pterinea, Actinopteria, Leiopteria, Limoptera, Mytilarca, Plethomytilus, Mo- diomorpha, Goniophora, Dystactelia, Megambonia, Nyassa, Edmondia, Sangninolites, Conocardium, Paracyclas, Posid- onomya, Microdon, Anadontopsis, Schizodus, Cypricardinia, Platyceras, Platyostoma, Ecculiomphalus, Euomphalus, Callonema, Loxonema, Bellerophon, Metoptoma, Tentaculites, Styliola, Hyolithes, Orthoceras, Cyrtoceras, Goniatites, Beyrichia, Leperditia, Phacops, Proetus, Dalmanites.
Upper Silurian horizon: Zaphreutis, Halysites.
Lower beds: Streptelasma, Monticulopora, Leptena, Orthis, Orthoceras, Cyrtoceras, Ceraurus, Trinucleus, Dalmanites, Illznus, Asaphus.
Non-fossiliferous.
Upper portion: Receptaculites, Monticulopora, Ptilodictya, Graptolithus, Acrotreta, Strophomena, Streptorhynchus, Orthis, Triplesia, Modiolopsis, Tellinomya, Bellerophon, Murchisonia, Raphistoma, Pleurotomaria, Hellicotoma, Maclurea, Cyrtolites, Coleoprion, Hyolithes, Orthoceras, Endoceras, Leperditia, Beyrichia, Amphion, Ceraurus, Symphasurus, Cyphaspis, Proetus, Ilenus, Bathyurus, Asaphus.
Lower portion: Lingulepis, Lingula?, Discina, Obolella, Acrotreta, Schizambon, Leptw#na, Strophomena, Orthis, Trip-
lesia, Agnostus, Dicellocephalus, Ptychoparia, Arethusina, lllenurus, Asaphus. _
Lingulepis, Kutorgina, Obolella, Acrotreta, Agnostus, Dicellocephalus, Ptychoparia, Ptychaspis, Arethusina.
'lraces of fossils.
Upper beds: Protospongia, Lingulepis, Lingula?, Discina, Acrothele, Acrotreta, Kurtorgina, Hyolithes, Agnost Picellocephalus, Ptychoparia, Agraulos, Chariocephalus, Ogygia?. ; i “ erro
Upper beds: Lingulepis, Obolella, Stenotheca, Agnostus, Dicellocephalus, Ptychoparia. Middle beds: Scenella, Agnostus, Dicellocephalus ?, Ptychoparia.
Upper shaly beds: Kutorgina, Olenellus, Ptychoparia, Anomocare.
TIN Dak.
[Figures in heavy-faced type indicate the page on which the description is given.]
Page. ACERVULARIA pentagona .....-.---.------ wees nies 105 ACMEA testudinalis ............--------- spremaaacesic 260 JNOTO YES Bits 3c Sancomm DODDS DRO Soa TID SOS LOC D ODOC OIC A 14, 69 WOIGHOLOMIB. 2 -s acca s\scavmricancwevecsece sien ene 14 IACROTRETAS snancie sa seuamcsssauaeseasen= sin speagasso5 16,69 PRE ED 5 se CaS COSC nCoCE Scr Oo SMeSSeISES S555 17 gemma .....- ------3, 16, 17,18, 20, 71 TSR OAR ASA Seis S86 SSB RSE aC PECANS eC rns 17 RRNA OTs uacapmccaoanccas SonboosncuOdocae Cee aco 17 INOMINOPUR RA: sacncnercitercecesaerenson sensor csens 166 VA GTINOP TERT ACs etae cinielaisinin'a slain cielsialna'vialsinivisin sie isi> sin 166 (ROA seeeceee eae eee aaeaea sa ceceiceeemnes 164, 166 ACTINOZOA 100 AGNOSTUS -- 2 24 IU GN Eee as coeasecebpoonsc 20 ASO CeCcOOSas4 3,17, 26,27 COMMUMNIGS. -- 2-225 0-5 ccacs ceases cecace Rena roees 3,27 INGOT Aeee fe aaleee en eeecenee nee esem aman comanetee 3,27 DRINCE DS eee ele wincdeinaise eee eels es ovis 25 Tend Wye aS 55555 4550S Se a SROs OaS EM SoSSane= Beso 28 Richmondensis ---- 7. ~- 5... 2 5 .c05 5. oo ween ee 24 seclusus 25 tumidosus 271 IA GHAULOB Me aise cacteeetisisine acre cease mae ennle aleinlete eitia 55, 61 PE LODOSUS meeteresieaiats sino ts ee sn lste owns) atelsiensiciate 61 (OMG scone Sasa Ace aoSocS SADOOCHDS DOS ence Cee one 55 SUP UN soy saad seas co ROS eee on See 55 ALLORISMA Hannibalensis ...................-..---- 244 SUIPOUTIGH be Vale oe melee ae cite ee a oe renin ce ial ac 225 terminalis 225 ALVEOLITES multilamellata 274 Rockfordensis 102 AMBOCCELIA umbonata 5, 276 AMP HION, reciente Sosa sient one eos eae aus acces 94 Nevadensis 94 eu Ukssoontescos els sonatas 272 AMPULLARIA......... Scdrnengsacsad AnscHassccosseensc 261 1 Powelli ....... GooeHeSo50c Honscc soot acess 8, 261,263
Page. AN QDONTOPSIB pee sean asa eeeieans nn paamavicees emcepe 180 amygdaleeformis ......2ccccencecccccencccscnsee- 180 ANOMITES cuspidatus .....-..- 219 ANOMOCARE .........--cce0e coescenncne 59 Scuminatom <2... 56 .c cee neenne eeneecee =n Sere 50 PF PALVUM cer owas san ane ecsesatcnns soccnewenssenmer 59
ANTHRACO-PUPA Ohioensis
(Crepicephalus) Oweni .-...-....-.---..--.----- 55 = Ptychoparia Owenl.............-....-.-...00- 55 PVE LY lot. Bap oc co pOSeRS0 = oansaanoaeeoopconn aoa 98 Caribouensigessecss see cese salem aaa ae aes seem 3,98 WOUTIOSALCe eee nfeseeecnten aoe seaenenccsee sera. 98 platycephalug) <2... 2)... ccc cewsecsnacennenna c= 272 (BUS eee eee fe alee te ee etermielewimin as mie oieleepmim 272 ASTYLOSPONGIA 99 RW seqsasenenccosacAaod 99 Nayarit) 535560 nos aebOHOee bsis SED EDOSHOCECROnODOSno Sos 148, 222 SAT pel Oa psa eee tesa nteere seco tenanantene toe 148,169 (CT Loses ae Saas Se SecA SSAA Saee ene aoa 149 (Oa aans cee eng e cn sheian FOSScOnH os seisnabSone ono 148 Tinh a tay Sa.a5 Sree on SnD OOOO SS OOO SDC ESO DOOCOO PPP] Mai geen ener te eens osiaset Unvitwsonciadecheancasaee 141 MGSN GA asee ee ee cesar cele cece cham incnn ee <nln/s cals 149 ULES 3 Sei goenseencad abo sesa D-H SoS CoS eS saaae 224 TEGO cee poe aeocp nc SERCO AROS ROSE EH ODH coca 222, 280 BI DIANE OB Bessa ce eee cia ome cin we sate lewis wminiain 5, 222 {Os = cea soon 50, ado asees sees noseoco cman 280 ETINU CLEA een esis antec einleisiemi= sine wnlc/-mminiateinsle' Se 224 Ri httesec a Se naesgre Svosece An dene omnonesoecnscs 148,276
287
288 INDEX. Page. Page. (ATRYPAD cas ckser GE CUERO Hod Co-COO nS SoSCoSOEcceneO 150 | BELLEROPHON—Continued. i 159 Mrer a 22 = cen ase nen Receeeccococosecercmoscces LEY 147 majusculus 256,257
desquamata-o--cc-s-s0seceeecceen== oteeosaceesc 150 Neleus= setae eeiae Reoceasensce oceoace 278
dnpliata a. a..cosnccseesenens sah sneeeaesee=e=— 155 Pelops..-..-..- Saosayscceee cee Seaecho aseSeS acs 194
Nagita ss-sessscoees Coresenecaecessaceseae= 148, 149 porplexa\-----+----==< --192, 193,195
TET OH) yee peer ecg eeO coc SEER EEE ea IeCeSeSanisS 155 subl@vis.........- RP RSereS Eno oe Se eeeECIe oo-e- 256
TAG iBlin sj aaedeee eee ces ees eee een te ee eae eal 220 Textllikteeee sess == ace Sees neeee ee ee 257,258
Ten ( iw Ss seme coc Meee SeeeDASrEIeO Sao 4, 150,151, 195 (Bucania) bidorsata.........-..2----02--02--22-- 271 AULOPORA serpens - O33) BEYRICHIAC- 27222 --aes== pes eeteenese nee eee eae 88, 204 (AVICUDA Boyle oo --nnacien dene s seen eoen~ sem =-nemnnn 166 Layette pens 5 mecca cece ecco TEROSGEsnE CISSOION 88
= Psendomonotis curta........--.--.----------- 225 ‘Wialkensianat.-o: Sopot e- ce oeeaeee eeeeaceee 205
; =. 165 ap.?.. 8s AVICULOPECTEN ..---.--------200-2eeeeeeree--eeeees 226 (Primitia) occidentalis..........-..--------.+--- 204
RV Be seenece Someta saps aoco: Hosta aces 29, 231, 232 (Primitia) simplex.--:-....--..-...-...... Recor 205
catactus --.. --5, 164, 276 (Primitia) strangulata .-...-...-..-..----------- 205
Coreyanus ...-.-.--000---2-0- ener sence anne eeeeee 229)1} BRACHTIOPODAC=o=seecesot bese ee ee eecen oneness 12, 67, 106, 213
Coxanus ..-..--. 0.0200 + eee eens eee rene eee eee ee eee 228), (GATTONEMAL(c.u.c=cs66e sees ee seeseerceceeessteneeens 189
curto-cardinalis 229 iniitaton. 22) << eee soe eeeteeee eeeece ree 189
Eurekensis .--..2s0000-<es----eccess-=- ZV ,228, 229, 231 occidentalis . 189
Haguel ..-.------2+0+-22e2eseseecees ees 226,227, 229, 231 | CarymeneE bufo var.rana.......----------+0--- stosey ROY,
Vinterlineatus ....--+--+-++++ esses eeeee eee es 225 TORU PNA See ee eee ese eee eae ene eee =a 210
McCoyi.-.------ 2257| GAMAREDLA Galeifera).2-.20-<se+ <= -0e--eee seco 71,75
occidaneus 225 |, CAMTAROPHORIA - c+ -coe sw =2ee-22-— sees eieaeuene es -- 156, 224
occidentalis © 225 (Cooperensis es = een nace ees eee 224
parvulus. .. 225 | Campriay, Fossils of the .....--------.-------+ eee 11
peroccidens 229, 231 Number of genera and species in ..-.....-...--- 9
PIN COGUAIN cones eee en eeeenaa seca SSeccees BZS || |GARBONTRRROUSsos- oa oe Sere aw ee ee 212
Utahensis ..------..---.----2+--+2eeeee ee eneee : 225 Corals-not illustrated ........2.-----cc-seeceeeee Ve
WWGDGTCUSIS bee awe see ner nae eee ae 225 Fossils of the ze 212
BD. Pose coe eesom nec nw ssencenaeccmanewesusennen=s 230 Species of Upper Devonian commingling wit'
(Pecten) plicatws coon eae ence aes eawaucece sine 228 fauna Of DLOWEGL: =<. <s2o-sceecehasaedececseece= 8 BAKEVELLIA parva. Number of genera and species in .. 2 9 BARRANDIA .....------5 ete cece ee cee e ween eee ee eeee CARDIOEAR Doe sae cnc nes eenets ee anes eee 251
PMcCoOYi.....-....cacecscennncsesesccsescernnna: Sfilicostata:: = 220. .ce0sse te eee saan esccsss- Ol
UE Mecsesees fe scone tece nace ncmenecensaccsoscnaces PET ANIS OPS alent = lane es eae 251 RATE YURUB saekieciee teewaiees ans ten noe tetas 91 | CARDIOMORPHA Missouriensis ..................---- 5, 6, 225
GEOR Ee) Be peers eecagecnc tose sore ecesses sess sa5 O35 | KGEPHAROPOD Ae ae nese cae enen nine ce aaa eee 86, 200, 265
Foongeneris.........--..+.----+s-sseeee-s2eee ee D2 WCRRAURUS == =e ==sen-e=ee =e sospocosatcosccce oe 95
Hy) Giro) Sree Bere a Rance eos sacctsce «- 92,93 {sp. undt....-....- Coo ctHoo scence san ness ssecc5 --- 95,272
fserratus .-...-........ Ssanwaesscoueesenaca=ncne 92 | CHATETES ..-....--.----00- sossorcosroreocmesas ccce 279
feimillimus .--... 2... .cccesccesevcenscecccccsses 93 | CHARIOCEPHALUS ...... 2-220 ccceeeseneneesoncceene- 61
tuberculatus . 91 imi ets oso ceeecscinon ese SS Cason oesoscccas 61
Oph) Peeeeeceece eee nee co eo ee Cr rcorrasern a3: 272 | CHEMNITZIA lavigata ..........-----0----------0---- 259 IBENURROPHON se] sense tate cece etencnnesee eee anaice ate 192, 256 subconstricta .....--..---- Posobt tS score socetecns 258
OBNCOLAEUN 2.55. eden eenes se <eeecc saa eceaeee 257 | CuEmMunG Group of New York, Number of species
Gombaliacssesesencslteat led anes acs eee tale eee 193 WEPTeSsON WN thea. .conen= =e enc enens-aecen asta 7
Costatus ....--..-ses---20. saccesonsresecerccsmen 256 | CHONETES ..........----2000 enceesee Petieh ces sees 122
CTASSUS)~se= -caqeee =eee a<saesanann an aeee ee sanee 256 aeutiradiata . 124
@lliptious <-2225 2... 22. SECECOREEHOSSAEO Ceonooc 258 ATcuata ...-.--- ccece REARS CER ROC ECOSOC aus, 123
194 COPOUAN sae cela seen eee cen secgocos oe 128 194 GHOCtA tesecc ead awe en caase 124
INDEX.
CuoneTES—Continued. filistriata
macrostriata ..-..--.-------
mucronata .-....- setigera....-.----seeee-------ene nen seer
ConcHYOLITHUS anomites pugnus.--.--------------- 155 CONOCARDIUM..-..--2-0------------ seer ens eeeessee 177 Nevadensis ..--------------+----20sereete etn 177 ConocEPHALitTEs (Pterocephalus) laticeps.--.--.--- 59 = Ptychoparia arenosus 55 CONOCORYPHE coronatus...---.--.--------------+-+- 48 @XSUIANS 2-- sec o---<5- se 2 a= wn sacins =o =n ese = = 48 Matthewi.------------:5-------- -o3---- <= 2---"- 48 Solvensis ..--.--.------ 222+ ---00- = e22c errs 48 (Elyx) laticeps 48 (Ptychoparia) Gallatinensis ---..--------------- 55 —=Ptychoparia Gallatinensis.....--.---.-------- 55 CONULARIA ----.---- ee e202 = eee ee eto eres Me 198, 264 Missouriensis 264 sp. undt.----- Sea ctee Ses EMA uen eee 198 CorALs, Carboniferous, not illustrated ...---.------ Devonian, not illustrated .---------------------- Silurian, not illustrated --.----------------.----- GRENIPECTEN .-----» ------ ----=------+ == 7 ==" 205-22" * 231
erenulatus .
Hallanus ...-.-.--.--200- ee --e ee reer rete: Tennent eee ace rise erect emtan annem smncinn com : 231 Winchelli . 229, 232 CREPICEPHALUS 46 Mentralisisnsses sasa= = ans wee anon nenn ins 55 (Loganellus) anytus .---------------++--++ te57- 56 (Loganellus) centralis.--.---------------++---->- 55 (Loganellus) granulosus ---.----------++-++--->- 57 (Loganellus) Haguei ------------------++ser++->> ° 57 (Loganellus) nitidus .-----------------------++7 57 (Loganellus) simulator.-...-.------------- 57 (Loganellus) unisulcatus 58 LOK ED AW
Page. CrePicErpHALUS—Continued.
(Loganellus) = Ptychoparia Montanensis -..--.- . 56
=Ptychoparia centralis.-...--..---------------- 55
=Ptychoparia planus. ----------- ccsccostohess “ 56
88, 204
163
163
163
planirostra 164
CTENODONTA contracta. - 76
CYATHOPHYLLUM corniculum.......------.:--------. 4 104 Davidsoni
CYPHASPIS ......-2----- 20-2 eee cee sense nent
previmarginatus ..-.--.-------++++--------0-5>> 93 CYPRICARDELLA..-..-------++---2-0222-- 22222572077 180, 250 CYPRICARDIA occidentalis. .....---..-------------+-- 225 PViGidD.----- 20. ---- eee eee e eens ene een tens 176 CYPRICARDINIA.-.-------------+++--2-202°" eet 182 WNGeNta ------ --cccccnonscacenccecncennceneen=== 182 182 CYPRICARDITES indenta ..-.--+---------+--------->-- 182 CyrtiA Hamiltonensis ..----.---------++----220000 > 147 GYRITIND) oo c22 acne co= Seme nate ceserensemereinnmesene= 146 Dawvidsoni.-.--..------------ e+ cesses eeee rere 146 Hamiltonensis 146, 147 heteroclita -.....------------eo-see serene eee -. 146,147 CYRTOCERAS ..-------------2eeeee es eeeet tere 203 cessator..-------------- 22 - ener ese tn tr e -278 Nevadensis 203
BD Al beset ea eaters rn oe iciee es oer e oe (Gomphoceras) Metula..-----------------.------ 203 CYRTOLITES ..-------------- 20-02 - teen eter serene 84 ginuatus .---------------++---++:--- 84 CysTID 273 CysTIPHYLLUM Americanum ...----------------- =~ 106 TISBD)Seasean eres seems oem en nam meena Sore 106 CYTHERODON..--------002-2 020-0 -2 tenes ects 181 (Schizodus) quadrangularis-...- 181 208, 273 209 208, 211 209 TING tpi) ae ao nee Seana SCS OC OO Ses ae 210 DAWSONELLA Meeki.-..------------+-+-2------7> <—ae 262 DELTHYRIs raricosta 135 undulatus 135 DENTALIUM (like D. primarium)..-.--.-----~----+-*> 281 TSVONTAN Soe = fon - oom esa omen wena enni =e o ors 99
Corals not illustrated... .-------++--------++0777"
Sommary of fauna of
290 INDEX. Page. Page. DEvon1an—Continued. EvompPuaLus—Continued. Fossils of 99 (Straparollus) Hecale .........-. oeescAStaccsasce 186 Ichthyic fauna of . 7 (Straparollus) subrugosus........--------------- 255 Number of genera and species in. .-..----------- 9 | Fauna, Devonian, Summary of ........--....------- 6 DICELLOCEPHALUBS ...... ------ ----ee--0-eee--- see === 40, 89 Fresh-water, in Lower Carboniferous 8 angustifrons .....-.-.------++++--+---2- 22202 ---- Ichthyic, of the Devonian..........---..-------- 7 bilobatus...-- of Lower Pogonip group, relations .....--.-.--.-. 4 Vexpansus\: sere-2h sae -mesneatea stone ee alba of Middle Pogonip group .....-----..-----.----- 3 PN ALIB oooh elton reese ea ee eae of Upper Pogonip group, like Lower Trenton - -- 3 Mahelliferscuccseesetonce ise coon coer oareesee Pecularities of White Pine shale ......-.....--. 5 ineXpGCtalll see seae ae ance seats , Passage, between Cambrian and Silurian........ 3 hole esse Favositrs? Argus Marica basaltica --...-.-.---. nasutus Whe miepheri es sec. a etek ale eee ape ee Osceola .SP ----------+---------- +--+ 2+ eee ee eee +--+ - quadriceps : 45 | FENESTELLA Sp. 1 .-.--.------2-------222----2---22-- Richmond GNSS: ©2226. s- see e a Seer ea cea -~ 44 | Fisturirora sp.? - DIPHYPHYLLUM Simcoense .....:--------+- -+-+=2-"" 405 | Fossits, Cambrian ....-...---------.----+-+---+-++-- Dincie eee (area tpee ee wipe ae. 112, 213 Carboniferous..---...--.--- -------------------- NERS TT el NR A ea gee S 214 Devonisn 12932. + sess Sone eae eee eens 99 Hodansiss Lower Silurian 65 ST ett Le pot ee ee eae Potsdam, of Wisconsin, occurring in Nevada. .-. 3 RAett sich ee nreeet a 60 Sees gee 412 RGSU GINA CYMNGLICE: nonce == = nae ela =e =e 279 WWISEOTTIGNGIB > o0c one seen cae eee alee 213 BR ea 79 Ste eee Seka SEES 8,213, 214 GERRI OF OD Agia 2 clereterate else aint ee eee 78, 182, 254 SPAN) siioge helene WR Ata rey 113, 213, 214 GENERA AND SPEcIEs, Number of, in Paleozoic forma- Hs ae es ee Pre aan 112, 268, 279 fiona (of CleritraliN eva a eae ra 9 Ormin Newberry oe ees 213 GroLocic Horizon, Table showing number of gen- Posen SP ie “nS era and species in each, in Central Nevada. ... 9 eRe 172 GDYPTODESMAUSD.fleese ae see eee eee 276 er ee A Ae eee a pa ee “Sansa ee eee res sessed i arssseseccsasoce 202 BOOUMOMPRALDS -cocseesctecteeeesceseen 1 celaye ke Nesaen SR aiealpe a ae aes SUDOVMOUNG eee sees esse e eee eee eee 202 Se BD. Pec crcc nme sso ac nnapaieanctensenwmaces ease <semc~ 281 HUN! coos aa GONTATIURA poe ee eee ees ee eeen eee nee eee ee 203 LEED ata doaideratese eee eee ee st Teter ae 203 TEEDMONDIA .------ 22 2cee 22 cece ceneee sone nse ene en ns 245 Ringic inks en Se ee ee 78 Phicarin ates ss esensne oe eae eee 176 epi yenceeane Saas teeter eee 9278 Burlingtonensis 2ASi |G GNTOPHORA esc hs sac ce ten ese cceeeea cote eee 171 ? circularis --. 246 perangulata 271,195 Medion ....-----++ +++ +-2- eee ee renee es cee eee cee B45) Guawcvard <<. Secs. saeo= eees te eases tenes ee 174, 244 Pingnensis secs sateta este see eect eee 164, 277 arotata cs. eiGldccpoecseas se semenoeeeeeoacee: 8, 226, 245 Enpoceras multitubulatum..-.-.------------++---- 87 Hannibalensia’:-secssss2scsenecsessenee ee 8, 175, 226, 244 proteiforme . winor 174 EUVOMPHALUS..--------+-se0e0+eeeeeeeeeeee seer eereee (Leptodomnus?) arcuata.....-..--.--.------ adesee 245 CY LES CCG 5 SS OOS Ot eco e 186 | GRaPTOLITHUS sp. {?.----.----- SorStecheceeecseesece ee ez Eurekensis 185 | GrirrirHives .....--- eepaes see 266 laxUe oe oces eee <eactie seinen 186 Portlocki 266 rugosus . 255 | Group, Pogonip ---..-...-.20+ ssceee---e-e-=-----2-= 65 BP. 9. .--- == nee nec e eee ee eee ee teen eee e enn nee cane 277 Prospect Mountain ......-..-...---------------- 1l (Eceuliomphalus) laxus..-....- eancccavecsseccuss 186 | GYPIDULA, subgenus...-.. sescrnccsaeo cbempstecsccn S5 159 (Phanerotinus) laxus ....-- Ba neiatatet Sceasscoss - 186 occidentails .......- 159
INDEX. 291 Page. Page. HAtysiTEs catenulatus ........---.--------.-++-+--- 4,273 | LEPTODESMA .... SRB ERE SEC DECI Btocsssocceaocs 167, 234 HAMILTON GROUP SPECIES...-..-°--------- ---+++- 7 ComplanawiM ooo non cen no severe ccasnmareers saa 234 PRTC OMOMANE iace's Sajna nin sinlniele ees = alain 81 MAVifOLME teem ssa saanqeasasson= == == --'n'=i= 0a nene 167 planulata .....-.--.-----.- +22 2222-2 een eee 81 TROT Gos ecembor cer aaseccr Ce nee ran acer asl 234 uniangulata 81 transversa ......-- Fa BML Lh ine Jere eee ee ae 81 Uh) oben Settee ete mcorreer eee a reo k epee esac 234 HemiPronitEs Chemungensis var. arctostriata SLL Zie | Wea FAC STC Re Ae cto late go rnin le mate ata niomnlameete == =a 167 Hurparionyx (Atrypa) consimilis ..--- -.-.--...--. 150 BATINOMWCIS cena anna a -b cen ace oncnedpeeeenes an 167 ERY OLIVES soe oe cae ene a neces s aa 23, 85, 199, 264 | LincuLa . 199, 264 affinis
264 PA DA pin en Aaja cetera sean eae s aos = .... 108 264 ETHERS, Go = ee COUPEE DOR EIG OCD SOURED Ee absas 111
primordialis....<--.---------- -----+-s02-+.2s02- 3,23
(Vanuxemi)..<2sc ose cs seos- ciao ase- sme -- 85
199 (Theca) primordialis ... ....-.-----.------.----- 23 Ligea var. Nevadensis 107 Icurnyic FAUNA, Devonian, in Kanab Cajon. ------ 7 Lonensis 108 TLLANURUS ..-..-----.--- ------ 222222 ene ee eee eee 97 Lueretia 108 CODNEXUBW ee ooo oc Aiea nee Rete ewe uc vena 7 Cito nO een semen sao C DOS DO TEC OA Oc Ww IEOOS 3,13 IN RAN p ig aceneool temas SARRSAREaatioe eet 3, 71,97 AN ICU Ein conse eee OSS ISS IDOE IE AEE ISOS 108, 274 QUAGTALOS 22 -)-<= = sm oan a=) oe wane enone 97 mytiloides .-.... .---------------+---= Sehepopes 108, 279 Gis oreo bacesseeeoan Ch acba a eee Reena 269 SEG Teun TOR Speen ne ee ease aoe eerie ea 109 ILLENUS W/L Py ee ecner sens eee Dee ee ace anos IO 5, 109, 111 GIaRsiCAUd eee neta oe seek. eins eke oe see aes oe 79, 272 GOs Vasase enti soos ie neO saa pac Ree saceeSQsNeae 270, 274 ii ae eSeee ove aaa Ace ees ene Ene emeearse Doha GING ULE PIS ene teenie ante atest eens 12 INOCERAMUS Chemungensis 168 Mepray <2 2-22-22 science omnan- ne nnts-onesacenanr 3, 12, 13 acinimiaeee 169 MODUS -tinincn soe wee ='= Rvs sens sacenaitaeeeas === 3,413 TPHIDR Ay hollasesese sess eso e nee aa ea ae ene 21 | LOWER SILURIAN, Fossils of ...... ...---.----------- 65 a bradoniGus | saseas eee nee ee meee oa 10M LO KONEM AC oe) em eene ne eee aaa eee -- 190, 258 RGU ENS Er ae ee beean he: seebeDenasesosee Beerala20 approximatum .....--.------------ 191 IscHaDITEs tessellatus 67 bell pce ccesawiecesnes oaect eeertee atest a see 258, 259 ACUMORGINA 25. <--=2-)--=0 BAe SRE CEN Sern 18 CEM UHMOLMIB Essen aaa = Saas emanates ees ece es 258 (tee t SO, oy Seeing SDSS ee SSE Gee eeaeones aa 19, 21 TOV GH en ae eece ee soem se On CUS EO ss essasaase 190 MIN UIRELA eee cen satis ge cceaene saom ates. socee 20, 21 nobile.--...- -----. 190, 192 Prospectensis.--. ...-...--------+---- ope ee sbed 19 RINEtGIEY be coedececthnsscubases mosseoses somasas 191 GERI) sonecensenenere Soseoceeneeues “Bmemesee 20, 21 subattenuatum ...-..........-..----------.190, M9, 192 With Olds ac ease owe ba sie asses Sa acs aE S ee ae 18 Crt he ome eer COE BESO RCCL Ona Ecorse 192, 278 THAMIRTUIB RAN CHIATA TE a5.) sone ana ae ee nee pence: 76, 164,225 | Lucina (Paracyclas) elliptica var. occidentalis -.--. 178 PEMIGRTERTA oo mto. sen eee ence ene a S-seesae tesco 166 | LUNULICARDIUM fragosum .------..... ---------... 5, 164, 277 Rafinesquii - ; MACLUREA.... -- Aen auee caer ee pesaaocdansos fess 81 LEIORHYNCHUS MOUS Baie eae enone eel see eae = ae 83 TNTICOSFAGUB emer eens ce conten) eases oes meena 159 CTD sae 8 oer dak ep seer co eenpacondeeeeeooon at REP sinnatus GAIN Sia eee eee eee eee ee oae esa oees 82 LEPERDITIA - AVENTIS tae ys eel en eae sioe cones 21 Diva peeaeeee na eke oe cae ences er eeine cenem nnn pubannalatial. os2o5 2c: encase cs ceses ee sessaces s2 Canadensis Che? eenees an lde fe Stcahs toae pect odoebaaaaias0- 83 TOLOMO StH seen sce i= cena wlea sence = e= === seeeeee 206 | MacrocuEILus Altonensis 260 Sp. tess ROG! ecesietcd 2 Hehn Sse SSeC IO SS Se Cee: yee ere 260 LEPTENA WDNR) fascist ete ae -eoce CeCe nRCOr ne Garba Meee 243 Melita SFian tl GON beet e ieee ase elena ds (an ese ae 8, 226, 243 sericea TEAS neacaenesaeeece hase e een eee justezcsivass 244 LEPTOCELIA sp. ? 276 tenmistriate ooo ee nos ce ann .--8, 226, 280
292 INDEX. Page. Page. Macropon—Continued. Myarina—Continued. truncatus peoncastctoo? 243 ampla ...-------s00-csenescnneee snes cencessnnsee 238 MARTINIA, subgenus...-.- maeneoherocoaear caccecotes 139 ApacheSi ....-...------+----eeece scene ASAcCa se 225, 237 MEGAMBONIA .--...----------0 5 Staaten EO ueee 173 aviculoides .. 225 Occidualis 2. -cesecerc- qoecwe cuewnsnaansmesaan 173 congeneris......-..-----+----------0-ee+ e2- === == 237 subcordiformis 173 Nemesis «22200. 5- 6-22 cn pen ncermennsensce= >= -=== 237 MENOCEPHALUS Sedgwicki 51, 54 INGSSUB ic oe sociatnre sa iesatataale om aie ommeim nletera infers 238 MERISTELLA ....-- 2-2 --- eee eee eee e ee eee ere ee nr eres 148 Permiana “ 295 Wligea..=--=2<<c~-sena= Sees bo Oo 148 St. Lndoviea. . <2 205-22 ccncecwececene==s0~ === 237 nasuta -.- Popeocececmaso EAE) subquadrata ......-...---------------+---------- 237, 238 tumid@s scence sccstecetenss seswnc===ensiasennenmes 149 PSwallovi.....-00..---0-----csesecnee Scowes lees 225 (Whitfieldia) nasuta ......-.----.---+-+++++-++-- 148 SDP fccesteeacens aah 295 METOPTOMA. -...--.----2-eeeeee eee ee eee- ~- 83,195,260 | MYTILARCA ....-..------------ 2202 eee ene e ee eee eee 168 f analoga. ...---------ee0--2- seen ee eeeene eet 84 Chemungensis --.--...-------------------+------ 168 @Devonica ...-..-------e--- ee eneee ec eee een ceee== 195 ODT yee Spenco con see mare acconinecne 168 Phillipsi .-....-------- eee-- -2eeee seers eeene cee §3, $4 oviformis ---. 169 peroccidens BGO | Spikes - 2) ween een ese c see senkeece me ewee === =m aewe 276 perovalis 84 (Plethomytilus) oviformis...-...--------------- 168, 169 TrentonensiS ...--------- se-seeceee nents 84 | Mytirus Chemungensis..-.-.----------------------- 168 MICRODON)--0=2- <ases s--2->-<~===2e2s-moeneew nen 180,250 | Narvicorsis (like N. equistriata).......-----.--..--- 278 complanatus .....--.--------+seee+seeeeetttree 180 EW peep eeeecoot Sere ro cerca G-Osiona ao seo 278 (Cypricardella) bellistriatus --- 250 | Nautivus (like N. digonis) ..-.-.-.---.------------- 281 (Cypricardella) connatus.---------------+-+++--- 250 | NUCLEOSPIRA ........---.----------------------+---- 147 (Cypricardella) gregarius- ---.----------- ++---- 250 concinna. - 147 (Cypricardella) macrostriatus.-+..------------- USO, 250 | NUCULA ..-..-.----- +--+ ++ +--+ eee erent eee eee e ee 172, 241 MODIOLA .------ }-=-----=" Beeee sag soo ceo see Poomaguen 239 ATAtA, <c<- 220 seers cone cedean ewer ese s naan 295 ?Nevadensis peee eens eee 51) palateintar soon ee ee Se ees 241 MODIOLOPSIS.----------- +2220 2 -eeee teeter i7 Pnnlaris eee conse eae 241 mytiloides ...---.--.--- 17 WiGwatars 2 ook es ee ee ee Sete eee 242 occidens --. 7 levatiforme 241 Pogonipensis...-...-----------02e0++seret sett 7s Niotigata- essere. tee aces rene eet ec teemmneeeets 172 Bp Menem eta non n1-lase eno ono one e ncer an 270 Rescuensis 172 MOopIOMORPHA......--.----------- serene sree F 169, 239 VATIGOBS Soe rai ae Sen ee eee ae eee 241 170 Fin Heese nes ees ne mee eece rs eseecbaacteeaas 172 169 | NucuuirEs triangulus 277 BSO)| NYASSA, cose seen nea Sea 240 PATVA ...---- 2.02 22-2 eee eee ee eee eee ee ee ese eee 240 PERiS Ge fencon ee eee Rae ne eae eee aaees 176. |MQROUENEA soe. secs cee. - ote e ee eel tence ae 170 ? ambigna Avi ChromatiGa ceoscsoeee eee ee ane ee cee aa 68 ¢ Pintéensis......-.---2-----2--eeeee eee ee 240 desiderata’s..0. cenesc. cessor san aomn-emacneatain 68 quadrula. ...--. .---------s2eeee ener ee eee seeee 171 desquamata...-..------ ----+++-+eeeeee seers sees 68 MMOoNOPTERIA Marian.....----------+---- e++-eeeree 7 225 discoidea MOoNTICULOPORA sp.? MURCHISONIA . - OGYGIA! 2 cose coe oon cca cee a ale ere eel nee 36 MYALINA 237 ? problematica 63 angulata ......ecee- +--+ eeseeceen nee ne ese esees 287 @ spinosa ......----------eeeeee eee e ee eee teens 63
INDEX. 293
Page. Fage. OLENELLUS ------ peniae aise neal a ele ima ele =nle 28 | PaALzomanon—Continued. asaphoides.-...--- ae nanan Hen ecee emawee 36, 37, 38, 39 Romeri.....--.- 99 Gilbentietes-sfcre-s sae eee 2, 29, 34, 36,37, 38 | Paracycias 178 130); (tl Unesco Sen ccadeeene 2, 30, 31, 32, 33, 34, 35, 37, 38, 39 elliptica var. occidentalis ......------+------+-+-- 178 TG ease sep Og cee ee ee eer es oe 28, 36, 37, 38 GCOINeN tals pa 2-2 saecct bem laa 164, 165,178 Thompsoni ......-.--------- --- 2-2-2222 ose nee 38 peroccidens -.--...----- 277 Vermontans ~~~ ---o- =. s-- == enone cee ens = === 34,38 | PARADOXIDES..-.-.-.------------++-+++------>- ee 39 OLENUus (Olenellus) Gilberti.... -- ee eer t gaat n= 29 39 (Olenellus) Howelli ..-.--.----------------+-+--- 30 231 ORBICULA Lodensis -..------------. -++------++-++--- 112 159 WIN MEA ee areca ee eae ee Bow saan hee n-wise nana 112 162 nitida . - 159, 152 ORTHIS.....--.- 20-22-00 ene eee ee eeee ee teens galeatiform .......--------+--225+s-0eeeeee sore ee 159 INTO KENBIS secon: same ees ala ajereale oie ewintwini=lm face nial= pp} galeatus . 114, 161 fissicosta...---...-.0..-c0ccenn---- <= cena no ceene= 73 Lotis -..-- 1G, 162 Hamburgensis . - 3,73 occidentalis.......--+.-----e0+eeereeeees eee eee 159, 160 impressa .-..-..------+-------------+--+-=- 4, 215, 169 subglobosus. .-.------+---++2-+2-eeeeeeeeee eee 162 imequalis........-.-.2--- ----- +--+ --- ewer e eee ee LUT#| WPHACOPH Es as se-ce cn eee = ook a aedeecre=ansec=neomaaa 207 insignis. -.....----.-----+-+--05----+--- ee eee eee bombifrons Seat 207 Towensis. - - TA ee eee ate seara nsec e aes seek scare es 5, 207, 211 Tonensis----.--... ce e0 cence = --~ = === oceans PHANEROTINUS paradoxus....-------- ~------++-+++ 186 McFarlanei PHILLIPSIA.----- Re ce on eee terns 211 OCCIDeNtANS cas asse= ee oes ee wale == wis lm alee mn 74 coronata D> BI Pecosi Lodensis 267 TGR MOISE ar on anim mminntnrnrnin ms misty am Cineelecc sno eiminice oi (Brachymetopus ?) ornata .---------+----+ ------ 211 perveta ..-...---.------ +--+ 2-2-2 eee e eee ee (Griffithides) Portlocki aanienapumeninenens=ncmen'ne 266 piicatella weet eeeese wee nee ee sean er een= poeeee cee 73 | PHOLIDOPS.--..-22---- 222222 e nnn nn eens nan eeesnnene 113 Pogonipensis 270 halla see sae coc oe 113 PIAVUS..---------2------- 2-25 2-2 ee eee teense 117 Hamiltonm.----2.--..---020s00---ceen0s--5--20- 113 resupinata ....--.---...---+.++--------++---+--- 3, 279 (Pak bE WE as Soa B5 ace aoeresegoccese sece 1,4, 72, 73, 78 ETIGOURTIN Hosa. h ee eoes see csh areas nance nae Self oneg Tulliensis i dere Ses Sosneeancs cosas aseekose sosseeecne 268, 273 Orvuisina arctostriata......----------------------+- 117 MILEIN Ashe pes ae a cie eee area aa saan 117 flexicostata .....-.------------+-2e2e2--25- = 236 ORTHOCE BAB coe cies cis oni nla wewinieecimelnesime n= -200, 260, 265 inexpectans- 235 annulato-costatum -. 265 Thi Gti aasesnacnao ceabcosecrba-ececepacbreasce 295 BebryX ---22-+ ---< 00.20. eee neon te e- eee emenes 201 Missouriensis .----.---.------------------------- 236 Ma) tl \aeease cl a= pen Sonne EEC EST Ioer Seni a ees 87 peracuta?..-.-. Soke enennet DAO SDQIeD Tease ceo aeiee 225 clinocameratam 266 spatula .-..-.-.----------- 236 Eurekensis 265 subspatula -. 236 seine ASS PHATVCR RAS coesbenetersian- pecs cesnamartecrane=== ==) Loa cod acutirostris -...... ae ee ree 255 carinatum 182, 184, 195, 254 conicum - 182 Oo See eee Conradi 182, 184 IORTHOCISRA TA CAE eg chelsea eres siae elena = anima ani dentalium 182, 195 ORTHONOTA Ventricosa....-..----------------------- 177 dumosum 183 PacnypHyLLuM Woodmani .....--..---------------- 105 dumosum var, rarispinum..........------------- 183 99 Newberryi -......-2-------200-- 2000-2 eee--=---- 184 99 | NOMOSUM 22 once oe en nse cctecsanvncceses=>ceo---- 182, 183
994 INDEX. Page. Pages. PLatyceras—Continued. Propuctus—Continued. occidens 254 Cl@ ANS on 2 ose eno anne ane me 215, 279 Piso 23 cecn2-se=< 254 Ris bOS jose cee eae eee a ae 134 symmetricum 183 hirsutiforme ....-....---------------++---------- 133 thetiformeissssse oan eee eet o ee sloe a= ine ene 184 lachrymosus var. limus 169 Mh etis tone see ee senna oan ae lama 182, 183, 184 lachrymosus var. stigmatus 169 undolatum 184 longispinus ......--.----------+-------+----+-+-: 279 PRAMVOBTOMAS coo oce eels enipnamadea se at= == 185, 255 longispinus var. muricatus ...-.--...-. .------- 279 MOMS) esos eee e eee eee 255 Maurchisonianus ------.------..------.----<+-=n- 132 . lineatum muricatus 215 sp.? mavicellus << -- -2---os-—- 2-5 = een aae abana enon 131 PLATYSCHISMA INebrascensis =: =2--=.-22 2. c2-- oe 2 eee neem eeeene™ 279 tambiguum Prattenianus .....-.----------------.--.-----08 279 applanatus punctatus 279 ? McCoyi pustulosus 13L sp.? pyxidatus 129 PLETHOMYTILUS, subgenus...-...--------------++--- 169 Bemirechienlatis : «cms eee sae ee nee 215, 279 OVAORMIB) 22 acs oe 2- ese ea eee 169 Shumardiangs) o-oo es ee ee 129, 131 PLEUROPHORUS .-..----------------seeeee--------=-- 246 -- 133, 169 costatus -- 246 | spinulicost® .......--.-..----------------------- 129 [Mee keds ee eee nen ate ee ee tre 246 ~---------5, 195, 204 subcostatus 225'| truncatus <.---2---ccsc-se0~0neco- en enna anon ene= 5,131 IPLEUROTOMARIA «<< 2-2-2 - -s.cce- concen ennn-enesee ce 80, 259 Serosae =: 132 Lonensis 2 sO (Productella) dissimilis ----..----..--.------.-.- 130 Nasoni....-......--.-----....------------=---- 78 (Productella) Hallanus ......--.------------.--. 130 Nevadensis -.--- SER eco ene Soe 6 259 (Productella) lachrymosus ...----.--------.----- 132 nodomarginata..-...-..--------------------- 8, 245,239 (Productella) lachrymosus var. limus......-..... 132 BDA oe eoeaane ener -271, 277, 281 (Productella) lachrymosus var. stigmatus....... 132 PLUMULITES . -----200----- 2+ 0-200- ceecenees--- scenes ss (Productella) navicellus -.----..----------- 123, A314, 132 PCCILOPODA..------------- +--+ 22222-2222 - ee 24, 89, 207, 266 (Productella) pyxidatus .----..----.---.-------- 130 PoGonip GROUP .-.-..-..--------------------00--2--- 65 (Productella) Shumardianus -.-....-...-.-- 128, 129, 132 POLYPORA sp. ?...------ 279 (Productella) speciosus 133 PORAMBONITES obscura 270 (Productella) subaculeatus. ....- Beene 128, 129, 132 PORIFERA..-. «22-2 ene ence ne net e ener cere ee en eee 11, 99 (Productella) truncatus ....-..--.-----.-------. 123, 131 PoOsIpoNIA? arcuate .........-----------2-00------== 245 (Strophalosia) Murchisonianus 131, 132 POSIDONOMYA..----------+ +--+ ++ ------ 178 | PRoeTus 210 Bronni 179 clarus 211 WeovOnieaseccen couce eee wee ec ee cia cin ete ain te 179 Wecoxvas) {225 -2ec accuse eons ee one eee eee 35 VP Wes Bepaanesee Sep CUL eee saacogorencdcco 178 ald emannt! --5.42ss2-42 sees eee ee ae 5,210 PotspaM Fossi1s of Wisconsin occurring in Nevada. 3 marginalis .-.-..--=.------------ -5, 210, 211 PRODUCTELLA..------------- 128 WONUSHIS.. a2. 2 ncne onan ene ecen enna wane nnn eee 35 lachrymosa var. lima 132 Ren Oo Deere eee eee eee mest 278 lachrymosa var, stigmata .......---.------------ 132,133 | ProspEcT MOUNTAIN GROUP -..-------------------- 1 navicella...--...-----------+--++ s++++----+------ 131 | PROTOSPONGIA .-...--.0--200-+---------------------- 11 Shumardianus 129 fenestrata specioga ...-.-.----------- eee ee cence ene e en eeee 133 BP. 9. ~~~ 222 ee nee ene ee ene ee eee e eee ener eee BE ee oe ese no OAS IOCOCS -o 131 || (PYESINEA SC! cc0 5-6 == 3--a~ 2-20 ene nen tetas eae PRODUCTUB -.-20<------- senee= enennscnnwesenns------ 128,214 flabella .......22..02-----ceee-e en nnee eee: GONCENELICUS <= - 22-246 eee es tewene=ceemees= ste 129 Chemungensis --- 166 215 Newarkensis 165 costatus .-----------.---en--<05 279 Pintoensis ..-..--.----------- Cece conse osoncey 234 Gissimilis -...-...------22..- asecceecseeee----- 130 | PTERINOPECTEN. ..----.-----------------=- eeageacoe. 232
INDEX. 295 Page. Page. PTERINOPECTEN—Continued. UEMONIFER A ss coconaes tan sncsnecasaucsm -ceens acne 261 233 | PupA Bigsbyi-..-....-...-.....-. 262 Z3F Vermillionensis. . . . . . 262 233 VenUAL A erceeen entesseseeiees sone neme samen sare ate 262 27 Ge | PRA P RISTO MA te neice eb eescy eee sia == =e =m ne 78 233 NASOMiss nea scees iaae elmer sweeeeat as sas eneraons 4,78,79 58 271 IPTHROR OD Bie cece sieae eee since min ness chem am alan alee 23, 85, 196, 264 (Plenrotomaria) Nasoni..----..----------------- 78 IPTILODICTYAGarbonaria---.-..----- 2 -- se -en3c~s Sa SRMGKPTAGUEITES sac-e = concen sss= nee noose amen ene 65 serrata-...-.--. wae hac se cet eee enn en nena nweena== BLN OUST semeneee estes ees seen ose == ahaa aoe 67 RSH |e Saar eS SSE PeC RP ape OcaS a CO Mee Eras meeiace: 270, 279 GLO PREUS sc = nas anna oss seociessasnssinwesss assess 66, 67 (RNS CH ABB IB sass aaee essa ae ate le ase if ielat 60 CT OSE ae alee oa wie eee le sea eae 66 HATATE ee ees Oee) eoagenne) esac repre ein oac 3,60 ANtUNO ULB eses acess es seas ee ee wae ele een ninecese 67 pustulosa -....----.--- 2-22-22 ee eee eee eee eee 269 TIGUIAYIA asec sees sa Spe seect ai gesscse tetas 66 PUN CHOPARIA 5 cowecies ons = a0 ~~ anne nse eee anaes =ae= 52 46,91 ATU WReoe te see sacl. aoc beseaceseeuecs<ksntee esses aoe ate 3 mammillaris fangulatus. ........--..+--sss-02 +22 ees ee eee eee BAU] aS eh ee Ee ye eee ee sacar Seeger PANIGUGANIA sec tan sleeker le lesa ee eee ee 91 | Recurrent Species, Number of........-------.---- Anytus ...-..-... SEC ASS psa Areso6 seen eeeeo 56)! ResuiTss Summary of: osc cece eco eccacew deca wccees calymenoides ABT Rta pee oe ese seo eae eee Bao eee ee (angi <5 see ge caneocooscdsersecd esas gomeooes 55 .. 220,221 TON ots qog SS SU ASSES CORA LOMO AL COO Sat OF an cea same 51 (bead eats PA MER UE wml olen sielm ie = olnlo elm ote man pean ROOD TNE Moreno niles ea scien se acc ce cece eoce aoe amas 990, 221 granulosus....---. -----+.+--2+ sees 2 eee renee sees 3,57 punctulifera: .c-csstwarsccenseesensecsseeacees 226, 221 Haguei ..-. 3,57 TACIAIIS ee cc Stes howe cos casteame ss onasee . 5, 22O, 221, 222 lwviceps --..----+-+- 0-2 eee ee ieee eee eee ee eee a4 radialis var. grandicosta 221 WLAN AYRSOM Ls os =n ine sim w osimynie =e ew nnn sn 2,47 RIAN ees Sooecsar Saoee dee Seenucon Soo ee SS boe 220 maculosus .-.-..---------++--+-+ 22250222 erro ee 269, 271 VOLG oe sc wiesta ae ds cevernscentee Goeirseesedteses 220, 222 - 9L Vornewiliana-. «2s se<sas2 sec nnsos-esesscesasccese 220, 222 TMG) ee eaeeiecene Cent eConeR Sone Senne eee 91 | Ruizopopa 65 Montanensis. .<---------<2<-----0----0eseneeense Do DOn ER ry WOH OMEBTA St. 2c ones ects cose eee cn aoe en ee 152, 223 I eR Sea oenoncnes Sopp eOSroreonene esac 156 Gas E ATI OS eae ae eels ne le aaa ete
BILIAGUB ee eeserias one tare ees es cissoe Cece ce acess ce 48
TNE EEN UT) Srccoasogcaae ono-doosenbagauosseeaece 3,58 BP. 9. --- = --- 2s eee nee eee ee eee eee eee ee 269 (Euloma?) affinis 54 (Euloma?) dissimilis ot (Pterocephalus) laticeps-........-...-------.--- 59 (Pterocephalus) occidens .........-.-....-...--. 58 (Solenopleura) breviceps..-. 49 PTYCHOPHYLLUM? infundibulum..............-...-. 274 [PTY CHOBTRET Ate see cence iene elesee sini cence eee 235 TNO sasesoqncse cance seencease dao aaa noeeeise 235 TORT GG osenosgeomecasnes oooc aosaose-sassee 235 GIES, sseaie- oc Seas Sonn Oo SES COoEzecosncesbee 235
Cooperensis. .----
cuboides ...--....---- BER ECO CCC CORD eCoe Sera Saae duplicata .........-------22-------- 22-2. eee eee 155, 157 Him Mon Gees ese aan ae oes ere eas eee late 154, 157 Eurekensis. 223 FLOVSLONdi ae woo ~ concn ce cee ceticc eae nsen = 5 ence 152 Sntenmediates 2° soos Ac eearese dee et oestec pees es 157 PU AUT Aro soecivaswwenes ascseaee-losssece=s = ene 159 Missouriennists-. se paces sooceseee castes sone see 156 152 UP NUR feces oeemtcine eens e nan eee tee ie 155, 159 PENIMOLMIB vere oeceeas seas ae avceseeeeaneeeaere: 156 BINNStAc .. sce esocae ooo aeaesoeeeoaes aaade oe 169 ROUGH se <= pom erian a's ow aiece nee saapocn sees oe 152 Thera venustula BD iaeeeies cope cot ae ane eaters ee cen cases 280 (Leiorhynechus) Kelloggi....... wseesebestesswacs 158
(Leiorhynchus) Laura
296 ‘ INDEX. Page. Page. RHYNCHONELLA—Continued. SoLENoMyA—Continued. (Leiorhynchus) Nevadensis. ...-....-.-----.---- 157 CUrte 328 - sssaceces coee duacn sew secieoceeee = eee 2az (Leiorhynchus) quadricostata ..-.-..----.------ 5) SPIEER cuspidatus?i-.-- << ie cmsenceuedeneaenne nen 219 (Leiorhynchus) sinuata ............------------- 158 INCTEDESCENA:: 22 as eee coven oscact veseaat-saaeee 215 (Stenocisma) duplicata....... --....------. ---- 155 Kentuckensis. -. 218 (Stenocisma) Horsfordi.....-...-.---.-----.----- 152 Neplectus|- so seers a severe ees ee eee 217 (Stenocisma) Tethys..... ..-..---.----------=-- 152 dotoplicnta hic ss. = --ere ese =an= «eee en 218 SANGUINOLITES . - 252 6200 656 ones cones sann as ener =-== == 175, 247 SPATTY ANUS eye nee ae nen eee snes Seen 137 8, 226, 247 spinosus 218 175 tri ronalis . sce - cesses se nceaa reece aeteeeee 215 175 PERG Ghee Se SoA neem acto ce cocoon cot see SES ch 143, 144 249 AVEC ORUA oe =niewis aren asia eats ene eee as 136 perangulatus ....--.---..--+-2e--2-- 2002-0 eee ee 171 (Trigonotreta) Pinonensis -.....--..--..-------- 138 retusus SPIRIFERA -- 134, 215 rigidus -- annectans 216 Salteri BL CUBOLTN CNG isos on eate alee a selena <i 136 ?Sanduskyensis DUNN GLA aoe enews ee eee ee ee a simplex .- 248 bisulcata .- striata 249 SAME Aen ae ae eee aeons ete VER TICONUS ses covet cao tecen care Osen ee 5, 164, 177 COM PACtA yaas-5 sm eeee tae celts caer eae aoe 143 ScENELLA 15 OLARSGiaee cies ai=inie eee aie ointee os enie oini cl aia NOt Gao eee eee eee once a era oa 15 desiderata reticulata 15 disjuncta ........... SCHIZAMBON, D. gen ..---------+- 0-222-222-2222 22 == 69 duodenaria typicalis ....-.:----.--2-++------ eee eee nero ee 3,70 Englemani ROHIZODUB nea sees cece ee ene ae 181, 252 ernbescens CUNGSHUSS sean sees ee nee ae nace nate = =e minnie Ree 245, 252 fimbriata cuneus 254 Braniicostata «<2: -2/-t4«-2e=c5=<5 pe ees se a8 215 WULTONMG ease ce a laesieh viklad en ainiatn = sta eiete aaa rate 253 Rennioottl. 255 .ineoss 2 ese ce seseneeeeecee eee 134 253 Kentuckensis var. propatula.........-........-. 218 252 Ree OMUK (Jato een aon eae eae alana eee 6 253 URE Epa ceoe so spesbdecacsaces co =sosSeeeer sss 218 EE eee ee ee Ce et 253 Leid yi - 222-5. 22-06 oe esa re ene e econ ne nnns 216,217 Wiheelert a5. 22. co-oas twee nnn eee er 225 218 (Cytherodon) orbicularis.......------- oe 181 141 ScoLiosToMA 195 137 J Gay Gialih Wal pee sogmake-ncosoe seas sso senose, Geass 195 218 Dannenbergii ...---.--.-------- ------+---- eee 195 137 SEDGWICKIA? concava.......---.------ seeecwesncnas 225 MO PLEOLA aoe ee ae tesa eae eee eee eee 217, 220 SeRPULA (Spirorbus) planorbites . --..------- 255 Norwoodi...--- \ gahe secede Vdeweswese sees eseneae 134 SILURIAN... .----------- 2-222 2 eee oe eee eee eee ee eee 65 OCHO GH tae aoe eee een ae ree Corals not illustrated..... ...-.----------------- 7 Parryana .....-... Lower. Fossils of........--.---------+--------- 65 RingnOnnikesdeces ieee sees en eee eeeds <a nes Number of genera and species in......-.-. .----- 9 PATCOStAL fcr ere ee eee eet. SIPHONOTRETA 69 Rockymontana . - NG 6 FG R GS ene SoennOone Onan oc er Cae OCOGSCnerinos 70, 71 segmenta wade whivdn dees gown aan monies ce ele p> ceslenatos unguiculata...-..--..-+----+22222 cece cere enn e ene 16 ANTES le eerie 5 Sonn CE eS ASenneecOnecoason Saat sche SKENIDIUM.....--..-------- asi aotenss ost a o00oe 116 BEPID OME oe eae cm nee a aoe eleee ae oe ee Devonicum .-.- 116 subumbona .-. INGIiGMIS . -.--- cence wee e nee e wees er seen see ecennnn= 116 subundifera..-.......----- aon Soo Sores 143 SwmiTaTa Hennahil . 22. oon. cicc een ceeeeer sear ance~= 274 tLaNslONs =~ 2 <a ean newer cen snenesenas===\emanne 215 SORENOMMA\ oo oe etmek me ta eee teeter 242 trigonalis ......-......-..- sonttcctce creseaceseee 215
INDEX. 297 Page. Page. SPrrirera—Continued. SrrepTorHyNcHUs—Continued. undifera 143, 195 Chemungensis ........-....--- Sans Oea ee senna 117 undifera var. Takwanensis. ....... eae se muicwbese 143, 145 Chemungensis var. A, S. Pandora ...-.-..--.---- 117 LOR Gn is eB oseeeebccce sees saad cor ereossons neo 134 Chemungensis var. B, S. arctostriatus ...-.....-. 117 TA nese Oe Bea Sane bone Ae pSSoeSeoseHesocboInd 123, 186 Chemungensis var. C, S. perversus .-.....-..---- 117 BY MATL Glare alate oem natn = 137 Chemungensis var. D, S. pectinaceus .........--- 117 (Martinia) compacta 144, 145 Chemungensis var. Pandora. .......---.--------- 118 (Martinia) curvatus var. undulata ......--.-.--- 145 OLEDIBULIA). wines sete sence s--- Lisshinswesseecees os 279 (Martinia) Franklini....-.......-..------------- 139, 140 5 (Martinia) fimbriata ----.-..----------------++-- 143, 145 117 (Martinia) glabra ..-.-.----------+-+-22---++-- 139, 140 15 (Martinia) glabra var. Nevadensis .. .-.----139, 144,145 | SrRoMATOPORA ...---..--------- secnacessdecn< 0208e- 100 (Martinia) levis --..--.---...----.--eee-----e-ee 140 RT cee spe enaeet esc sadeo C06 Osos AISI 274 (Martinia) levis = glabra ......-.--.----------- 145 | STROPHITES grandteva ....--..--..-20cceeseeeneese-- 8, 262 141 | STROPHODONTA 118 441, 142 Rnb peescsessenasssoocesso <co-Sep coccconeere: 118, 121 (Martinia) meristoides....--..-.------+--------- 141, 142 ALOUALR See eee ano ee cae e a ok See cim manne tan 121 (Martinia) ovalis .....-...-....----------+------ 145 (OPS ence eeessrnece COs rpso eee aaeepomas 122 (Martinia) pinguis..-....---.--.---++---+++----- canace ...... DEES eascaicesoccseceee co = 275 (Martinia) planoconvexa. --. demissa 118, 119 (Martinia) prematura .........---------------- dimosa ? 118 (Martinia) pseudolineata...........-...--..----- fragilis 120 (Martinia) Richardsoni ...........-..0....--2-00 anequinadintaysesa- ates aaa aeseoee canner eseaee 120 (Martinia) setigera 144, 145, 146, 279 Patersoni (Martinia) sublineata...........-...-..--------- 141, 142 CNOA ae eee eae eee nates nia eee pe (Martinia) subumbona .......-....-..----------- 142 punctulifera (Martinia) subundifera ......-.......--.-------- 143, 145 quadrata (Martinia) undifera...-.......- 140, 141, 943, 144, 145, 146 | SrropHOMENA (Trigonotreta) argentarius........-.......-..--- 138 arctostriata 117 (Trigonotreta) Pint6ensis --................... = 138 bifurcata 117 DBEERIR REINA estes ee ene ee een nee ae ane 218 Chemungensisico------=sesoa-=eeaeeaeeeanesa eee 117 GUIstatac. 5 2soa2 |= west eeiee sa oceasecessens 5, 218, 219 OQONISWIS ene on c-=-lssca arcs = © Seacecscscscee cs 120 insculpta .- 219 delthyris. . ceo Kentuckensis 218, 219 Gemissa 2 -eec sees Sawer sccesodescse ee agsene Kentuckensis var. propatula .....- .....--..... 218 SibDOSS ee === == See eeo aces nena sh cam ee aes 123 GEIR? ees SE See ne nee o BS SnCECsos 218, 219 inequiradiata ........-....... meaaaoscopsacnasces 120 (SUNOS pocsosd ia cene osganodo Jeo Hae SOON sea oe se 218 HGR PE EY 268 ioe Stor sssbecsee poosoosse soe 120 SprRicERA (Athyris) hirsuta -- 222 maieeesse ee 132 SPIRIGERINA? Tadialis._----..-.-2-2 5. --0560-2e2crees 220 mucronata 124 ESDRIN OWE C Ale cee eta siete leila lee ee ee 23 INGMOA see sa eseeee ease seen osecm anes cecssccS= 71 GIGI EE cecincccnS carb Shon ospncedRhassceeaeennese 23 TICE. OS eter a letetet ele en ie ole ect win eee eee laine sisi 120 SIRAPAROMHUSSe oo sae oa cy cee teee ce ccter Sat scecsuc 187 Patersoni Saran 119 INBWALKONSIS ee ceee meno seseeemen cee ees 187 POCUINACER senses ceecsx meene tate enon seasons 117 thes sscesess | dSaocasesSStbr seatnssconesetensss 271 PERE eo So ccenbcepeSAneS Senn pecOooosOICSIaCe 120 (Euomphalus) rugosus......-...--.------.----+- 256 pluristriata 120 (Enomphalus) subrugosus ......-..--..-..------ 256 pustulosa 131 STREBLOPTERIA 230 rhomboidalis 118 DROVE RaAN aetna nee mane einen elem na en aie 231 setigera : 125 RUM ILIS terete ee se ae iene aa eine sicees/s aaa 230 (Strophodonta) demissa..............---.-.----- 119 Lenuilinestasessesssesoen eecee ss accoenccemereaes 231 (Strophodorta) inequiradiata ........-...-...... 120 STREPTELASMA, D. sp .--...-- (Strophodonta) Patersoni......._. 119 STREPTORHYNCHUS DIEU DIO Ates arte eee ee rine aes came tao 197
298 INDEX. Page. Page. StyLioLa—Continued. TEREBRATULA—Continued. CUA VULUR pone oe oeeneuesin nae cencncs esha niteiaintente 198 PUQNUG cso ec cas peices ee soot am eee eine 155 WISSUTElB-nan sees sane eeceniecee ne Ssnoct2 2: 197,198 TACIGHB\.--s2-5 0 cane ne esse eect adaiees eases 220 fissurella var. intermittens............---------- 197 sp. ?..- 276 SYMPHYSURUS. $5 | TEREBRATULITES cristatus ...............-.------ Bas 218 ?Goldfussi OF. | Caasonsops! ep: '.<2-e- =< .ccce sae enue eeees en 274 SYRINGOPORA Hisingeri.-.........--.---.------------ 4,103 | THECcA primordialis 23 PULOLGLRNG <a -6 66 5 eee eee eee 5,103 | THECIA ramosa .. 102 multattenuata .... : 979 | “TREMATORPIRBA...--. 25. --.02c000-- cnennntemans seems 151 SYRINGOTHYHIB (oce-2s ccecen= ceased aecoss=seae—aees 219 151 Cuapldwtal sesso seen nee ee mee aes 219, 220 151 TELLINOMYA ....-.--- SS Soc Ponce Gace CO EIOE SA 76 151 IONELA GUA a oe ce ec ee ee rem anicle eutele ciemte wietolninsiale = 4,76 211 ?Hamburgensis .. 3,76 273 MYOLOUsA esas cee risce races cee eeaceeenaem ae eee 905 | "TRIPLESIA .- 2020. ceeccn nn. cones ew cccen cee ceesensse=e 75 (Ctenodonta) astartwformis .........-..-.------ 7 GalOM Or aces eects an eee eran aa ce toca ae meinee 3,75 (Ctenodonta) varicosa 77 | TROPIDOLEPTUS carinatus 276 TENTACULITES .- 196 | Uprrr HELperBerG Horizon of New York, Num- mttenuiatus sc eee e eee eee weer cee 197 ber of species representing. .....-.- 7 ellalis see oo kane anaconda lee el leon cc ae 197 WHITE PINE SHALES. .-.------------+ +++ .-02-22002- 6 pratiliberintuas 2220 eet eee tes 196 Stratigraphic position of...............--..----- 5 ASTER TAT ee Se See dete PS 197 WHHITFIELDIA - 2-22 ccc ec se cess a cceee cc cnc ces cemenss 148 PO ccc precc lates Sane, st A SSRIS Boor Gcaas onc 149 WISCONSIN, Potsdam fossils of, occurring in Nevada 3 ZAPHRENTIS? sp.? . 273, 279 ZAPTYCHIUS. 225 pence n seen e 263 CANDONATIA |. =<. < sacs ste-e atesa< studae sa careee mes 261, 263 ZonirEs (Connulus) Priscus ............-..---.----- 262 Zyocosrma Headi..-..... See ee eron come ean 150
A GROWRETA GEMMA. 2 oo ac totapointalo ease = sah coe a ere he eete = oniee eieae aia nee Sere eee a eee eee ee 17 Fig. la. View of the posterior side ee the ventral valve, enlarged to six diameters. 1b. Cast of the interior of the apex of the ventral valve, showing a cast of the sipho- nal tube and the elongate muscular scars, enlarged to six diameters. lc. Interior of the dorsal valve of Obolella? Scabrine Callaway (after Davidson). 1d. Interior of ventral valve enlarged to six diameters. le. Exterior of a small dorsal valve, enlarged to six diameters. 1f. Interior of apex of ventral valve. See plate ix, figs. 9, 9a.
OBOLELLATAMBIGUA 2 - == <2oc onan deen ne nes as ee se ae ee een en ne ae eee ae alate aera eee 67 Fig. 2a. Dorsal valve with the central portion of the shell exfoliated so as to show the median muscular sears, enlarged to three diameters. 2b. Exterior of ventral valve, enlarged to three diameters. 2c. Interior of dorsal valve, enlarged to three diameters.
SCHIZ/ARUR ON MISE IC ANGI la elma tale alee ere te ee ol aera 70 Fig. 3. Interior of ventral valve, enlarged to six diameters. 3a. Exterior of ventral valve, enlarged to six diameters. 36. Interior of dorsal valve, enlarged to six diameters. 3c. Exterior of dorsal valve, enlarged to six diameters. 3d. A portion of the surface of fig. 3c, enlarged to show the minute surface spines.
NUDDHKOVEENOY COTES: PALME E Gano Song Sooo onan sc CosSon coc nonon one abo omer cson pense oonstocececocice 83 Fig. 4. View looking from above. Natural size. 4a. Side view of same specimen.
MM OTLOTORSIS OC CLO EINE = eter eae ele aaa la lee lle 77 Fig. 5. Cast of the right valve. See plate xi, figs. 14, 144.
MODIOLOPSIS Eh OGONIPENSIS oer te tale eee eeltete ate etal cle ate a telat eter 73 Fig. 6. Cast of the left valve. See plate xi, fig, 13.
VQ OU VRE SOON IN TES oe Sag o5 Sosseodecas Seer soces Coan Ocoe so esod Ste ses oases serscces 20 Fig. 7. Upper surface of ventral valve, enlarged to six ee This figure is drawn from the type specimen from Montana, described by Mr. Meek. 7a. Posterior view of the same to show elevation, area, and deltidial opening. 7b. Enlargement to six diameters of a specimen from the Eureka District. See plate ix, fig. 7
PIB HON OME A UN GIRO TAA eae ere a tere pellet ated tala fe fore eiee eele rea eee 69 Fig. 8. Interior of ventral valve (after Davidson), Introduced for comparison with the ventral valves of Acrotreta and Schizambon.
IPTYCHOPARTA}? SIMEDIS: ‘Var: ROBUSTIUS) «ose neseae ee ees= ae oe eae eee eos eae ne seseeen aeanee 53 Fig. 9. View of the central portion of the head. Natural size. 9a. Outline of profile view of the same.
DICEETVOCRPBATUS HINER PEO DANG jar mints ea ean ae aie en ine ee ee coe aero ete 90 Fig. 10. Central portions of the head of a small specimen. Natural size.
METOPTOMA ? ANALOGA.....-- PC ODOR OA DOS OSES DDO at Ori De SHOAIB SOE ACS e SSH eS soSnoSSOose oan 84 Figs. 11, lla. Summit and side view of the type specimen. Natural size. e
MURGHIRBONTAUMIMGERD <\o.osts capt eclosion ato alate en ee inte le ecstatic 271 Figs. 12, 12a. Front and back view of the same specimen. Natural size. 12b. View of a cast. Natural size.
BUCANIA BIDORSATA. « .. .--= =~ 200 22 2 en see eir en ens cee mrinwee tees senncece acne santos nonecscecens 271 Figs. 13, 18a, 13c. Back, lateral, and front view of a specimen denuded of most of the shell. Natural size. 130. Enlargement of the surface of another shell, that shows the characteristic sur- facefines.
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LINGULA) ATBA-PINENSIS 2.202225 cn ecim cee amininn (e amna ate mint emia tele == ela le eg = alee lola iat Fig.1. Broad form, enlarged to six diameters. la. Elongate form, enlarged to six diameters. LINGULA LIGEA ...-..-.---------- -- BE BOON Bate ochre caso Cn QO OSC Ded Sone I Seno Sos IMEC Sam cS Fig. 2. A typical specimen, enlarged to two diameters. ,
LINGUA JUIGEA, var., NEVADENSIS = om = oc ate weit ain mm elm altel petal ein mm elie Fig. 3. Specimen showing the more attenuate form, as compared with fig. 2. Enlarged to two diameters. Vids (Cio) 67 AN IO Ole Soar CeCe eect OS0scH 9050 GuaU Com ea doS S55 saan aesancocdeeescocSansesencoss Fig. 4, A distorted specimen. Natural size. e
IDISCINAS IGODENSIS) oie ayea cnet oa ae rata ale oer tae lle orate eee pelo latte ete ee ata ott eel a
Fig.5. Ventral valve. Natural size. 5a. Dorsal valve. Natural size.
1247 COMODO) LINO NO00) WneaaooEoreoeas ocbee COD SOSb aa se Sane SoG sons cambousitos cada ceececaso
Fig.6. Ventral valve, enlarged to six diameters. 6a. Cast of interior of ventral valve, enlarged to six diameters. 6b. Interior of ventral valve, enlarged to six diameters.
PHOLIDOPS| QUADRANG ULARIS oi oo = 0lmie| oa at ate = wal miin ele mel ets lel ol intel etler «fa melanie) = oteteletetetottelar Fig. 7. Enlargement to three diameters of the type specimen.
GFONE TIS UB ERG TA 6 a oo im oe ata wre tmp ale miele mmm me wil ld el Figs. 8, 8a, 8b. Medium, transverse, and short forms of the ventral valve. Nataral size.
STROPHODONTA DEMISSA....- ~~ 222+ 2+ 0-22 = ee ene cone ne eee cee ce enn eens wn es eee ee en weee Figs. 9, 9a, 9b. Lateral, ventral, and dorsal views of a specimen from Lone Mountain.
PRODUCTOS HERS U DUE OR MB es eterno eae feta ett ee lear
Fig. 10. Enlargement to three diameters of a small ventral valve, preserving three of the slender surface spines. 10a. A large ventral valve, showing a portion of the outer shell and cast of the inner surface,
STROPHODONTASINEQUIRA DIANA sere cose eis else se a ae aaa eels el eee eee eee Fig. 11. A strongly-marked fragment of the ventral valve. lla. Enlargement of the surface of fig. 11. ORTHIS TULLIENSIS ...--. .--- <5 22-2 n = oo none renee oe coer oe wenn we nee mene ewe nn nnn enn cces Figs. 12,12a. Lateral and ventral view of an average size specimen.
CHONETES MACROSTRIATA Fig. 13. Dorsal view. Natural size. See plate xiii, figs. 14, 14a-c.
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PEAS eieioie: Page. SPIRIBERA (MATA o5- ore -lanmisissne won tnenceiennre ets oleee anwae eae el sina eee ea ale ee eet eee 141 Figs. 1, 1a. Lateral and dorsal views of young shell, showing area on each valve. Natural size. 16. A globose form with a lower area on the ventral valve. Natural size. lc. A similar form to S. (M.) meristoides Meek. ld,le. Ventral and lateral views of a transverse form, with a high area on the ventral valve. (S. subumbona-like.) Natural size. See plate xiv, figs. 13, 134.
Cyrtina DAVIDSONI ...-...-.- -- BIB CBS See eon ocos qaaatenco PEbaSsSnaancoor de Sodecrtase Seeaccoc 146 Figs. 2,2a,2b. Basal, dorsal, and side views of a strongly-plicated specimen. Enlarged to three diameters. 2c,d,e. Views of area, side, and dorsal valve of a smoother shell. Enlarged to three diameters.
Poppa Og LY AOpen Sri ame ae acon reece so arose Ssoonod hats Sesc cose Gano ccoscusesscacs 143
Figs. 3,3.a,b. Dorsal, ventral, and side views of the specimen mentioned in the text as of the type of S. prematura Hall. Enlarged to two diameters,
TERS wiz 0s) (HO) Oslo ae BO Bobs He SSee DoS See Sos oes ose Secs os se hao gas Sane Sess sooSse Sone essoss 159 Fig. 4. Dorsal view of a typical specimen from Independence, Iowa. Natural size. 7. Same view of a smoother, similar form from Nevada. See plate xv, figs. 5, 5a, b.
SPIRIBERA) GLABRA, Var. NEVADENSIS =<. oc) asismet= =) stasiae ei eee eta eee scoeas 139 Fig. 5. Dorsal view of a less transverse specimen than that figured on plate xiv, fig. 14.
SPIRINERAD UNDIN ERA 6 = ope 9 om'5 onl = == spe wie Vole eam eas = ma iene mt ee olen aloe 143 Figs. 6,6a. Dorsal and ventral views of a specimen with closely-arranged cencentric stria crossing a few low, rounded plications. Natural size. See plate xiv, figs. 11, lla, b.
MGR TSCA (CVV ic) NAS DAS oereje cet lata mteiteere alate tele mi atta Soo Sense Sten Hse SS5SehSre cos 502 148 Figs. 8,8a,6. Ventral, dorsal, and side views of a well-marked specimen. Natural size.
PENTAMERUS OTIS 2s- 0/o22 ceiein = Soe wise te relsisinlew oteye tate en eminent aaa ree orate ote eee 161 Figs. 9,9 a,b,c. Four views of a typical specimen. Enlarged to two diameters.
UNITED STATES GEOLOGICAL
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PALEONTOLOGY OF
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Page. SPIRIFERA PINONENSIS...--- ---- ---- 2020 once en ee cece cans nee cn ee ne wan cee nn ee cree coee noes 138 Figs. 1,1a,b. The original figures of S. argentarius Meek. lc,e,f. The original figures of S. Pinonensis Meek. 1d. Dorsal view of a specimen from the Eureka District, in which the radiating pli- cations are finer than in fig. le. Natural size. SPIRIFERA RARICOSTA ..---- ------ 022-00 oo ane ce nnn oe wen sen cn cee nnn nae ae semen es esese secs 135 Fig. 2. Ventral valve of a specimen with numerous plications. 2a. Same view of a shell with few plications. See plate xiv, fig. 12. TREMATOSPIRA INFREQUENS .... .- ---- 2222-222 eee cee enn ens emcees cence cow n ns wane cen ene 151 Figs. 3,3a,b. Dorsal, ventral, and side views of the type specimen. Natural size. CRYPTONEEDAG PINONENSIS)=2 5 22> on eo seee tee e noe eee eee eee eee ee eae 163 Fig. 4,4 a,b. Dorsal, ventral, and side views of the type specimen. Natural size. MYTIEARGA DUBIA -2.25-.-2-6 «22 25- -n 05 oenle witwinin ele nie eee sienna s amisie sional am eae ninmae 168 Fig. 5. Cast of right valve. Natural size. 5a. View of anterior side. i POSIDONOMYA LEVIS ...- .----- -<20 occ c een e ane cece oe cen enn ee nnn ene tan cone ewe ce wanes 178 Fig. 6. Right valve. Natural size. POSIDONOMYA DEVONICA ..---. --2200 c20- coe ene wenn oe nn ones conn nnn nee nee ene ene en nns 179 Fig. 7. Right valve enlarged to two diameters. MODIOMORPHA OBTUSA .... ---- ---- so secs cons cece cones cone come e meee ce eens nec ene cones cone 171 Fig. 8. Cardinal view of right valve. 8a. Right valve. Natural size. MYTILARCA CHEMUNGENSIS ..---- 2-2 22-202 -- ene cone cone cone cece oe ce een cee nnn one sane cnee 168 Fig. 9. Right valve. Natural size. SANGUINOLITES ? GRACILIS..- .- -- 2 -- 2. 22 = cen coe cons wees ene cence mene wsen ence cscs cecc cece 175
Fig. 10. Right valve. Natural size.
4b
MiEGAMBONEAS OCGEDUATIS |= a semyne cnrstnl orale a a ae ol li Fig. 1. Left valve. Natural size.
ACTINOPTERTAS BOW DY (oe ooo ale oe aie ale =n alee alm aim ele lata ante aie lm eee a Fig. 2. Left valve. Natural size.
TEIMOPTE RA] SAR ME NDILODA sooo late tote alee chain ycotatate lores see atin ima ene asl ie ete ieee tee ee tee et
Fig. 3. Small left valve. Natural size. 3a. Side view of 36. 3b. Large left valve. Natural size.
SANGUINOLITES ? SANDUSKYENSIS.....-
Fig. 4. Left valve. Natural size.
Micropon (C.) MACROSTRIATUS....-.......---
Fig. 5. Right valve. Natural size. e PTERINEAWELABE LUA cs a0 cco oe oe sonjacee motesectena seenionane seer eens = ieee ener et -
Fig. 6. Left valve. Natural size. See plate xv, fig. 12.
MODIOMORPHA) ‘OBLONGA! o-tecme- canis --)ssite cee: cms seas eee eee eerie See ete Sgt aracoe Fig. 7. Left valve. Natural size.
SOHIZODUS! (CE) FOR BLGUUARIS foo elate terra atm ime lteter al Fig. 8. Cast of right valve. Natural size. 8a. Small right valve with a more strongly-outlined postero-cardinal angle. WOONONA AVEIRO OT) Bee eoe a5 Bo SEED OSD Sao nob chased Sneses sabe SoS OCSSRED SEeScoOS see Fig. 9. Cast of right valve. Natural size.
LILWIOPTERIA. RAWINESQUIL 22522 <6054 3-22 Secceas cseme ce Soleo ete nee eee ome cee aaa eaeeveee
Fig. 10. Left valve. Natural size. 10a. Small left valve. Natural size,
NGYTIAR GAS (PEE DH ONES DEEUS)) OVO RIMES etal e cet eaael oteel a Fig. 11. Cast of right valve. Natural size.
IPTERINEA UNEWWABKIENGIS ac fomes cele onal oe satel e isis aeiotae eta at teal eee el te ole Fig. 12. Cast of right valve. Natural size.
TGR PTODESMA TRANS VICRSA terse etem ete ae me ciate eee ae te Fig. 138. Left valve. Natural size.
GYPRICARDINTAVINDENTA Ss ooo niece eee ne ee ene ee eee ins acelceeioemeesci= =a BoORae SeeeeS Fig. 14. Left valve. Natural size. See plate xv, fig. 11.
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UNITED STATES GEOLOGICAL
SURVEY
PALEONTOLOGY OF THE
EUREKA DISTRICT
DEVONIAN
TEN EGA EID) \Y/ AL
SCOLIOSTOMAWAMERICANA sa. occ 2 == siosine wren ee elbee eiete ieee ele eee ae atiseteleta a fae ale ateeetele ete late tnrete
Figs. 1, la. Two views of a specimen showing the aperture with the columellar lip broken away. Natural size. 1b, c, d. Three shells showing the inturning and expansion of the columellar lip. Natural size. le. View looking down on the apex of the spire. Natural size.
PLATYCERAS UNDULATUM | ---. 0oc00 1 ocecen cane mone oan = one oes een en ene aan eens === Figs 2, 2a. Dorsal ard side views. Natural size.
EUOMPHALUS (P.) GAXUS -<- - 6222 coe foc e cen en sane amie = own = wee ene = oem nam ae ee wen Fig. 3. View of upper side, enlarged to two diameters.
PLATYCERAS “THETIFORME «<2 - a -os ome awe em wie lets ws el wlan maint a = ter ol poste Oe one el Figs. 4, 4a, b. Posterior, dorsal, and side views of the cast. Natural size.
PLATYCERAS NODOSUM .----- - 02 2< 2<c- -n0e cone nnee ennn canons ae enn anas eens saa sna =a == === Figs. 5, 5a, b. Posterior, dorsal, and side views of the cast of a strongly-marked specimen. Natural size. ECCULIOMPHALUS DEVONICUS..-- <--< -205 2056 co cen- owen conn ome eons wane ones <n ons === == Figs. 6,6 a. Dorsal and ventral views of an adult shell. Natural size.
LOXONEMA APPROXIMATUM . ~-.-- 22.060 05000 00s cce once cen nne ce enews woe wes serene eeenee ess Fig.7. A specimen with the apex imperfect. Natural size.
ER WOTTTMES Sp sie sears cre ete alee ere ata att ea te el le ell Figs. 8, 8a. Two views of the only specimen obtained. Natural size.
(Bfo9 71-10) ofan 17. N90 Cpe Re ESE EEO CE OD CODES OCCOO TD DN Suer DOCeHsenee DSta eet cccccescsoecesesse cece Fig.9. A fragment of shale with numerous tubes lying upon it, enlarged to two diameters.
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UNITED STATES GEOLOGICAL SURVEY
PALEONTOLOGY
THE EUREKA
DISTRICT
PL.
VI
DEVONIAN
Pe AMISH leks
Disciya NEWBFERRYI Fig. 1. Lateral view of the specimen figured on plate xviii, fig. 3.
ERODUCEUS SUBACUDEAINUS-seeerieces=n= cea eitee eee ea sete eee eee eae cee eee ene eee aee Fig. 2. Ventral valve. Natural size. See plate xiii, figs. 19, 20.
DISCINA CONNATA
Fig.3. Ventral valve. Natural size. 3a. Side view of fig. 3.
DISCINA NITIDA
Figs. 4, 4a. Interior of compressed ventral valves, showing the smooth inner surface and rougher outer surface marked by strong concentric striz.
RETZIA RADIALIS
(A series to illustrate the variation in the number and size of the radiating surface plica- tions, all enlarged to two diameters. )
Figs. 5,5 a, Retzia Verneuiliana Hall, a specimen from the Lower Carboniferous of the Little Belt Mountains, near Clendenin, Montana. 5b. From the Devonian White Pine shale. 5, d,e. Lower Carboniferous forms from the Eureka District. 5f, g, h. Upper Carboniferons forms from the Eureka District.
RHYNCHONELLA THERA
Figs. 6, 6 a, b, ec. Dorsal, lateral, and ventral views of a typical specimen, enlarged to two diameters.
TEREBRATULA HASTATA
Figs. 7,7 a. Dorsal and ventral views of a somewhat crushed specimen. Natural size. 7b. Lateral view of a more perfect shell. Natural size.
SPIRIPERAUDESIDERATA: SoS ae Santee croc cece sein oe eee or ce See SE ee ee Fig. 8. Dorsal valve. Natural size.
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— = -—
UNITED STATES GEOLOGICAL SURVEY 7 PALEONTOLOGY OF THE EUREKA DISTRICT PL. VII
Gb
CARBONIFEROUS
ey v S ei ae
PASE) Velen:
PTERINOPECTEN SPIO! -2 sess sec aeise se elec seer eee eis emine eats eee ate ee eee erate ete
Fig. 1. Left valve,in which the surface has been largely removed, leaving the radiating costs and concentric lines in strong relief. Natural size. la. Left valve, on which the concentric lines are faintly defined. Natural size.
MAGRODON; TRUNGATUB < se a me ww cremate mm imie emia nm mlm walt lal lille alli Fig. 2. Left valve, enlarged to nearly three diameters.
PLEUROPHORUS: MBEKI co<- sees ey ele coe ele ciste mie ccleaner terete sine ester ee tha rt Fig. 3. Cast of left valve. Natural size. STREBEOPRTERIA. SUMIEIS ace. ose cies ee l= ma eae alee eaten la a tera anti oleae ee
Fig. 4,4). Right valves. Natural size. 4a, 4c. Left valves. Natural size.
4d. Finely striated left valve. See plate xix, fig.7. PTY CHOPTERIA-PROTORORME) 222 :2 = coeias sae eens Sen oat ea Seen eae ee eee eae eee eee Fig. 5. Left valve. Natural size.
AVICULOPRECDENDINTOENSIS( sca = njatac a= melee ne oe lesiatete te ler ale ere eet tet etal te el Fig. 6. Left valve. Natural size.
(Oioin@anfomony Jeli eWQUiiscom Soameo soocoo yoasee Soo som en DoS HOoca Soaa ss ene sce sos escasoneSs Fig. 7. Cast of a large right valve. Natural size. 7a. A small right valve. 7b. A large left valve. Natural size. 7c. Enlargement of the surface to show fine concentric striw crossing the radiating plications. AVICULOPEGTEN) PEROCGIDENS wca- ts anicinasicten saab are ese see Sait eee eee eee eee Fig. 8. Left valve. Natural size.
PTERINOPECTENDHOOSAGENSIS 22m ]o cian cnices ef anno oo ee oe teeee ene eaten See Fig. 9. Left valve. Natural size.
Page. 233
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CARBONIFEROUS
Cambevan
PROSPECT MOUNTAIN GROUP. U.S. Geological Survey. Geology of Eureka District, Plate IX
G.B Sampson Del T Sinclair & Son,Lith
12 Ged) be
KUTORGENAWEROSEPEOLENDSIS 3.5 252 ois sniee enw cece ona celoa salsa Gadelecen/ncohocos Seeccceneeuces
Fig. 1. Dorsal valve, enlarged to three diameters. la. Ventral valve equally enlarged. 1b. Restored outline of the two valves united.
STENOTHECAGELONGATA\ jw ocisicece sels ocjaiceceiscns Seawierae hiatal fatal alsin nisl Maiciaisietais ieiminl= cistaiaietaja aeons
Fig. 2. Upper side, enlarged to three diameters. 2a. Lateral view of the same specimen.
LES CRU BRST GROIUN penne SS OSE ORS CED CIES BESCTO BA SOEE UEIO BOO SCH ECB CEE EOSE HEE soso St = Fig. 3. Ventral valve, showing the more ovate form. See plate xi, fig. 2.
KU MORGIN AS WHIT MLE UDD cnsois<a/oa soe nto ceninte san oe cleus nl oeininaeelns als saa ece rice veces Gece cers
Fig. 4. Ventral valve, with outline restored, enlarged to two diameters, 4a. Dorsal valve, with outline of convexity below. Natural size.
EROLOSPONGTASHENESTRA TAC OB) COL w cin leraiacine s sjoSeniacio ee sani be Wee cccane scan cescecesucss Figs. 5,5, b. Three forms of spicul#; 56 is the more unusual form. Natural size.
SCENEDUAW ICONICAG soe of mee iatie e mince, cae oseisine nici cama tis wtna cle siecacdciewe obeys Seba wooed teectesses
Fig. 6. Posterior view, showing the elevation; the slight groove is very much too strong, it is scarcely descernible on the specimen.
KemORGINABSC TLE CLES re eeme tee e ape m eral sem me matenc ceeicmisiae)anneriise sane seseniaaceseinase ce 5a50 Fig. 7. Dorsal va've, enlarged to six diameters. See plate i, figs. 7.7 a, b.
(ORM SID) SOO ENE) Pane Jose Soa beccococe dSUe SU CC OS EU CESSES CHRO BEBE BS Boon OSS -CAbEoone oes Fig. 8. Dorsal valve, enlarged to three diameters. 8a. Ventral valve, similarly enlarged and showing the cast of the muscular scars.
ACROPREVACGEMMA, 225 Jaeenieacsacteasoce .caceulecwess secee < PH acoantEocne coco SSSear aSncsc! accor
Fig. 9. Lateral view, enlarged to four diameters. 9a. View from above of the same. See plate i, figs. 1 a-e,
AGNOSTUS RICHMONDENSISE >. - -s---cle.co-ciese> cose eoee BaiRSE COOCOC QOE RES EONS CER COOO COU HOSES - Fig. 10. View of the cephalic shicld, enlarged to four diameters.
AGRODAM LEE DLCHOTOM Ale sm cnaieeina mine nic cache sian ate min een ee oe eaiseee ces So0666 SE6a5¢ ——— Fig. 11. View of the specimen described, enlarged to three diameters.
ODENEIGN GS SLDDING Siem sarjanteniants aries) acre celom = sacle ss esis See eee acne nedeceseccices saoadescg Fig. 12. View of the type specimen, enlarged to two diameters.
A GNOSDT SEBUD ING manent forces ts alpanii es etree sicee ol selene oo aioe oe ace odes ome c ee waes
Fig. 13. Cephalic shield, enlarged to four diameters, 13a. Small caudal shield associated with the above, enlarged to five diameters.
AGNOSRUSERECLUSUS a itten tarts eielomie ans arn ioee ss) eh eo ae ete sestaaa actos es aeeinwis(sivaniacs/ces's eecece Fig. 14. Cephalic shield, enlarged to four diameters.
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14
PLATE IX—Continued.
QLENEDDUS HOWELL 2 22 30- secre olewivine = nyo oe = nin amia al =imee fe alate oe alla ele aoa Fig. 15. View of a specimen fully developed, excepting the presence of an ocular ridge, and the distance of the eyes from the glabella. The genal spines are too short in the figure. Natural size. 15a. Natural-size view of a head hayving.the genal apgles carried forward; eyes without au ocular ridge, and the angles of the posterior margin strongly marked. 15b. The head of a young individual, enlarged to four diameters, in which the embry- onic features are still more prominent. See plate xxi, figs. 1-9. 15c. Fragments of thoracic segments associated with this and the following species.
OULENELLUS GIUBERTISse2 3-222 oc ease wee emcee nee ainlale ele a ate oe (ae eae tate Fig.16. View of alargehead, Natural size. See plate xxi, fig. 18. 16a. Fragment showing the glabella and a portion of the palpebral lobes. Natural size. AANOMOCARE! # PARVUM + osc ec tres isso sae alata ae iat a am ella lee ew le ote ese le tattle fila Fiz. 17. Enlargement of the specimen described to five diameters. The outline of the pos- tero-lateral limb probably extends laterally a little more than in the figure. PTYCHUPARIA (?) LINNARSSONI ..---. .----- 22-200 cee one ce enn nee ne enn enna ans nese enen Fig.18. View of the broad form of the head, exclusive of the free cheeks, X 2. 18a. View of the narrow form, similarly enlarged. IDICELLOCEPHAT.US# XPANSUS =e ome e serena mays setae ate ie nic eae mee ae eel aetna Fig. 19. View showmg the character of the glabella and the peculiar ridges crossing the anterior portion of the fixed cheeks, enlarged to one and one-half diameters. PTYCHOPARIA (7) PROSPECTENSIS ..---- ..-- 2. - 2-20 <2 w ee sown e See en ene ee nnn eee wenn Fig. 20. View of the type specimen, enlarged to three diameters. The furrow crossing the glabella at the second pair of glabellar furrows is not seen in the specimen, PTYCHOPARIA (PTEROCEPHALUS ?) OCCIDENS .... .--. --------- 20+ 22-2 -- 0 one enn one ene Fig. 21. The test is largely exfoliated from the surface of the glabella, and but one pair of furrows are shown; figure enlarged to three diameters. OGNGIACS) PSPINOSA: 22 2 oso sac a ce om note enn eee leew ele ete le ate elm inal = inform lem oa eaten elie Fig. 22. View showing the central portions of the head. Natural size.
AGRAULOS GLOBOSUS
Fig. 23. A minute, very convex head, enlarged to four diameters.
DICELLOCEPHALUS ? QUADRICEPS
Fig. 24. Small head, enlarged to three diameters.
DICELLOCEPHALUS OSCEOLA..-...----.----
Fig. 25. View of specimen identified with the Wisconsin species. Natural size.
PTYCHOPARIA ANYTUS
Fig. 26. Central portions of the head, enlarged three diameters. The fixed cheeks are more elevated at the outer termination of the ocular ridges than represented.
ARETHUSINA AMERICANA
Fig. 27. View of central portions of head; the ocular ridges are stronger than in the figure; enlarged to three diameters.
PTYCHOPARIA (E.) DISSIMILIS
Fig. 28. View of fragment showing the central portion of the head. Natural size.
Page.
59°
47
45.
46-
58-
61
45
40:
62
5h
ay ? i
(), ease lenses Cambrian PROSPECT MOUNTAIN GROUP. U.S. Geological Survey: Geology of Eureka District, Plate X-.
G B Simpson Del
PEA aE ox.
DIGEELOCERHAVUBHT VAN GUS TIE RONG is- nae cmanier es conde om os Sclocen tec cab onic bake weulCawercecceacs
Fig.1. View of the movable cheek associated with the glabella, la. View of the glabella, palpebral lobes, and outline of the convexity of the glabella. Natural size. 1b. A pygidium occurring in the same hard specimen of rock. Natural size.
OGYGTA)T PROBIE MANOA sano e an oe en sec tame ceed Seitesleuasiscoa messes bowede cawece
Fig.2. Usual form of the head of the adult, with the facial sutures and outline of the con- vexity of the glabella. Natural size. 2a. Pygidiuim associated with the head and fragment of the thoracic pleura, repre- sented by fig. 26. See fig. 4.
PTY CHOPARTA\ OWENI- s2\o2c scte'sinela =ieieis Secs sice oo clei seeieeiee ee see ecclcb aces ccc ctawecsecicwccees
Fig. 3. Nearly complete head within the facial sutures, enlarged to two diameters. 3a. Pygidium associated with the same, similarly enlarged.
OGY GIAVIEPROBLEMATICAV= <= 52s cciaces dec s esses ooSs,coas/scuesccostesbccss anes ceccieecccecass
Fig. 4. Enlargement to four diameters of a small head, in which the movable cheeks are absent, the postero-lateral limbs are broken away, and the glabellar furrows obso- lete. There are specimens intermediate to those represented by fig. 2 and fig. 4.
EY CHOPARLAY OCCIDENTALIS! -sielsis ome aanocls aein(= isin iaeielsin(a 22 alesse sana sein ton(oSsious\eomocsicncess Fig. 5. View natural size, showing the features of the glabella and fixed cheeks.
IDICHLEELOCEPHAT US RIOHMONDENSIS te ieicts ain ciccisiode ss sa cleieiscte ce isis sie seleso cin te eivin Seecieiseanic
Fig. 7. View of the central portions of the head, showing the broad frontal limb and fixed cheeks. Natural size.
IPTV CHOPARTA TEER RNASUEUBS eo = nie ale cclascaiSa cates oe woiesc ays Sema aisoccict dele Semin soemce meetmswces
Fig.8. Upper view of the head parts discovered. The nasute projection of the frontal border is a little short in the figure. Natural size. 8a. Movable cheek, associated with the preceding. 8b. Lateral view of the specimen from which fig. 8 was drawn.
PTYCHOPARIA (SOLENOPLEURA) BREVICEPS ...-.---.---------- aeeiaetelsicertelamieieee aloes enaiannel Fig. 9. View of the type specimen to show the broad, short form of the head, and rounded conical glabella, enlarged to three diameters.
ET CHOPARLAG (G) ISIMITESeemacerrae sy orccloser neste aicecne-svee sales seabed piwcae cece <0
Fig. 10. Enlargement to two diameters of the central portions of the head, showing the char- acter of the frontal limb and glabella.
DOHA, -- - 2 ooo doecea Gags SoA POS OnSnS 2650 COON 0500 Kade GEEO EOS CBOE HOD ESD EDE EES GEEBe Fig. 11. Movable cheek, associated with Piychoparia unisulcatus.
PIV. CHOPARTAG(hin ) PAMEINIS fetine a cisisaemisc en iaa cate cckiaa selec ce laioala's'ajcens lem Sriemicce socniocanelnae
Fig. 12. View of specimen, showing the narrow frontal limb, as compared with fig. 10, and the strongly-marked glabellar furrows, enlarged to two diameters.
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51
41
49
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52
PLATE X—Continued.
DICELLOCEPHATUS MUARIC Avenir ana cele ore lalals (sta eteremisicteiecleteieiomiaintas lets matalteteteteieintes =ttsteeeteeteeioret ate
Fig. 18. Enlargement to three diameters of the central portions of the head. Fig. 14. Free cheek, associated with figs. 2 and 3.
DICELLOCEPHALUS NASUTUS -..-.---------- go Soave vas aclesie ion clecins eect ee eee eae eel
Fig. 15. Central portion of the head, showing the glabella and prolonged anterior border of the head. Natural size.
CHARIOCEPHATLUS? TUMIRRONB spice oe cle ale = (ele seine sie metealele mele ate late ele ale la oelere ele lain oat se ala Fig. 16. Specimen showing the frontal margin, and a less protuberant frontal lobe to the glabella than in the type of the species, enlarged to two diameters. Fig.6. Pygidium associated with Chariocephalus tumifrons, and supposed to belong to the species.
(POY CHOP AR TAGE AU V8 RES etal lalate alee a = ee eee ee ft Fig. 17. View of the central portions of the head, enlarged to three diameters, with the pos- tero-lateral limbs broken off. 18. Free cheek, associated with the heads of this species and P. Oweni.
JD olieifoyerbese MLO) WON aes secSeo Gobdos nS0bES saeco ocoassduobese noone gocestoscceé cooges ses5 Fig. 19. View showing the strongly-marked features of the central portion of the head of the species, enlarged to two diameters. Fig. 20. Hypostoma, associated with fragments of a species of the genus Dicellocephalus, enlarged to three diameters.
IRIE (0) BUNUN a Bio pa A eB Ob OS DOO OS OBS BO COS DOE CHORD GO DOORS OCS FOO Seo Sd cb ascocsnstecomsos Fig. 21. Strongly convex hypostoma, associated with Ptychoparia Oweni, enlarged to three diameters. Fig. 22, An hypostoma, similarly enlarged, associated with Ptychoparia anytus, P. Oweni, and P. leviceps.
IPINY CHASPISUMINUMAtso ee wey cele cel ele cp alee wom cle cieteeia ce aaieleis eelseteee sine lieionintaele cata meletaeiata tener
Fig. 23. Enlargement to four diameters of a head, showing the elahelia, fixed cheeks, ocu- lar ridges, and depressed frontal limb.
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43
Silurian
POGONIP GROUP. U.S. Geological Survey. Geology of Eureka District, Plate XI
So
127) CyeN G01) Oe
TELLINOMYA ? HAMBURGENSIS .. .----- = ec cce cece cone cone cone cece nn wean nn cone wacc es cece ence
Fig. 1. Left valve, enlarged to two diameters, to show the fine surface stria. la. Same valve, showing the posterior margin more depressed, which is the usual form of the species, enlarged to two diameters.
THOS (CORDA | NUS PO COU TO Woe An BSS S585 p55 doce Slee DESC ED Go OS. o 5 CHEB OBS D SOB DEB eOBO OOOO 000000 Cood
Fig. 2. A specimen of the broad variety of the species, from which the outer surface is exfoliated, enlarged to two diameters. See plate ix, fig. 3.
(Orit ynol VAM = ce5 edd SeSe SHED ESO 6 SSUES EE BOCES OSS Con OST acea pene podesoornectspenscr
Figs. 3, 3a, 3b. Dorsal, ventral, and lateral views of a characteristic specimen, enlarged to two diameters.
ORTHISCER IC ENA UAW a aetee ota sereeieteeie esc oisinio nia sleislodee es sleine ere mnlateistelesmiastwini=tai=inlaiairi<in'=is=
Figs. 4, 4a. Ventral and dorsal views, showing the strong radiating coste and form of the valves, enlarged to two diameters.
ORDUBISUELAMBURGENSIS) 22 <2 eee 3c oe cis etecioe eaten le einieole je =icla civ ave wleiwie wie senleiwinin, ain alninininiacisisin'e
Fig.5. Ventral valve, enlarged to three diameters to show the fissicostate plications and general form of the valve. 5a. Same, of the dorsal valve.
ORTHISUDONENSIS coats nate os sie ee oon cereice cise wie iels slo cielociu aciom seewipclewa.c os -snclcms'ecmscicne nse
Fig.6 Ventral view and outline of the convexity of the ventral valve. Natural size. 6a. View of the area, showing the triangular-shaped foramen.
IP RIPERAPATCALOINE RAG M aa en nec cricisisacicicicisisceisaccie wastes sicfascictecelsleie's lanier cielvininl= «== nseloaisia
Fig. 7. Ventral valve, enlarged to two diameters. 8. Ventral valve of this or an allied species. The valve is convex and the median fold rounded.
STREPTORHYNCHUS MINOR... < .-. 2.2.00 205222 - <5 20 nen ceo ence co ce cn ne on enn ns =n o= monn ocr nner Fig. 9. Ventral valve, enlarged to two diameters.
ORTHIS TESTUDINARIA...---. .----- e222 22 once ee cere ne cece cece ee cee n ne tances ceceen ce cece a Fig. 10. Ventral valve. The cardinal angles are more rounded in the specimen. 10a. Dorsal valve a little enlarged. RECEPTACULITES MAMMILLARIS- .... .----- -2-20- coe- cece ne eens cece ee cece ee ence eee saceances Fig. 11. View looking on the base of a small specimen.
RECEPTACULITES ELLIPTICUS ....------ 20+ ----0+ cee e ne cone coon ee ennee apres ossSsocoscesses = Fig. 12. Lateral view.
MODIOLOPSIS POGONIPENSIS .-.--- ---- +--+ + eee ene 22 = ween ce enn cece ne cen ee ee cece ee eees = Fig. 13. View of the left valve enlarged to two diameters. See plate i, fig. 6.
MODIOLOPSIS OCCIDENS ..-. - ---- - 0-20 ee 2 ene cee ene ne ce ene cee ce en nn cee ne cee e cee ens tee neeee
Fig. 14. Outline of a large right valve, as seen on a weathered surface of rock. 14a. Smaller right valve, showing the exterior form. Natural size. See plate i, fig. 5.
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72
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73
PLATE XI—Continued.
TRELLINOMY A: CONTRAGTAM ac leciet fice eleeieinals Sala ome sea ce ie ciaea = atahaiaie ata einisle eee om area aaa itor
Fig. 15. Left valve, enlarged to two diameters. 15a. Interior of a smaller specimen.
HYOLITHES: VANUXEMD)< sc oo ce wcicene tcimcsorinsicl ste wisioesleae ot ooatese nineteen nie raceeee een matane
Figs. 16, 16a. Views of the ventral and dorsal sides, enlarged to two diameters. 16b. Transverse section of the tube.
COTE OER TON CEN WD Ae ere en eel te eee
Figs. 17, 17a, Lateral views of a straight and slightly curved tube, enlarged to four diam- eters. See plate xii, fig. 21.
MACELUREA. SUBANNULATAG so rccin a ecient tas eraare te =) ola ate tal etctatad nistaia tate elo iate itor Teataie lee a eat eae arti oe abate
Fig. 18. View of the upper side, showing the depressed character of the spire and the an- nulations on the cast of the outer whorl. 18a. View of the lower side of the same specimen. 18b. Section of the outer whorl.
MU Nop y op WA ONGOING Cho coos bncbonos SoCo Sops> Coos DIoDEO Eoccor Saasioe HSsassSoscos cosseesc Fig. 19. View of the lower side, showing the annulations of the outer surface of the shell, enlarged to two diameters. 19a. Internal cast of the lower side, similarly enlarged.
MACLUREA OARINATA sence cise ete eaten SOR ROU CEOS SanO HO COES CaO a SEER OcOSonae Saco aceneecae Fig. 20. View of the lower side, showing the strong surface striz. 20a. Cast of the lower side.
RAPHISTOMA™ NASON metesie ele ete ata a ce aya malate atin tele = flatts ale eee tlm l= mole elated etait le mth atelnlet Figs. 21, 21a. Lateral and summit view of small specimen.
PLEUROTOMARIA LONENSIS..-<-. ------ 202-00 ences cone conn coerce cove wane cane nance scncesas= Fig. 22. Lateral view of the specimen from Lone Mountain. Natural size.
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Silurian POGONIP GROUP.
U.S. Geological Survey. Geoloéy of Eureka District, Plate XII. a
G.B Simpson Del T Smclair & Son, Lith
eA eee eile:
Page. PEINDOGERASEPROTEIROR MER teenies datsaee somata tisctis hes eee clo cocissicowaewises soninocleaeno<istere 86 Fig. 1. View of siphunele with included tube. la. Cross-section of another specimen. 1c. Opposite side of upper portion of fig. 1, -howing annulated shell of the siphuncle. FORTHOGMRAS) SP staece cece sic cer aa ee Sen onaeR ee anak tered ee oes Seu wct oceans cetutes cebewe 87 Fig. 1b. Oblique, transverse section. The outer shell is restored and is too small, aud it is also less circular in outline. The fragment crossing the siphuncle is of acci- dental origin. LOR DHOCERASWADot oases e ais cine smclat oe ee ccine cee cere ieee eee tic nesses ete ceric sews seers 86 Fig. 2. A portion of the shell, preserving a number of the septa and a portion of the siphuncle. FORTHOCERASHMULTI CAMRA TUM? = 222-05 sone lees ssenietien ce nec eciei ew c= ieee ees ieee ee tee 86 Fig. 3. Fragment showing the form of the tube, the septa, and a portion of the siphuncle. ETON UR US ee URE REN GIS tsetse eens seen eco eae eeeteeae aaaeeete cise eels este tae ae eee peas 97 Fig. 4. View of the central portion of the head and outline of the convexity of the same, enlarged to two diameters. 4a. Associated free cheek. TBARRANDUAUT IMG © OMiae elite) ctereia two cniels ioiwiciaieieo cetecloee casts ats leiaia'e folie s pbs eeiticlec se cefceclea cs 96 Fig. 5. View of the glabella and fixed cheeks, and a longitudinal outline of the convexity of the head, enlarged to two diameters. JU NEPASIDIN (Es Ul 2sen occsceesedso se eho case sa rec S50 Oson on oops SHaecoc SobeDoneSbo Hose SSonene 96 Fig. 6. View of the glabella. Natural size. BAS APH USE CARTE OUEN SIS oss 'ciniere niet estates mister e eee ataeiniat oleisiset te Sela oieteteinint= micietcl<)ai= = sie ele te / 98 Fig. 7. View of the head within the facial sutures, also outline of longitudinal section. 7a. An associated free cheek. 7b. Pygidium found in the same association. EP AEVURUS te CONGENE RIB ee aps seta cisines isle siecincieematemelesnc as oe <ielseeinioesclccice/scicieesiccice seer 92 Fig. 8. View of glabella and fixed cheeks, enlarged to two diameters. 8a. Pygidium associated in the same layer of rock. DATHYVURUSEDUBERCULATUS! = scccie csc leeric~ se riscwieciasiesenioe - << Ssooncigacoeducned suas cboane 91 Fig. 9. View of the glabella and a portion of the fixed cheeks, enlarged to two diameters, SC MPHASPISHIBREVIMARGINATAS cc< cone so cess cs seus ce sniseas cece oe tclcecseacccesucesesses aces 93 Fig. 10. Enlargement to three diameters of the only specimen discovered. DACORUM GM RUM LIMU = se veecinee sale ae eeetseeceetatene cscs ssc ciceccicace scnciescsccccchsessce 93
Fig. 11. Enlargement to three diameters, to show the character of the glabella and frontal margin.
PLATE XII —Continued.
Page. DICELLOCEPHALUS BINAUIS "heme maar anette eee ase ee eee See ee 89 Fig. 12. View of the central portions of the head. Natural size. 12a. Associated pygidium, enlarged to two diameters. 22. Portion of a thoracic segment on the same fragment of rock. AMPHION NEVADENSIS..o2.0..c-2)es¢c-00-eeeece---s Se Seno Sen one SS cee dG 6Os0 Se OAS SAO 94 Fig. 13. View of the portions of the head preserved in the type specime. Natural size. 14. Pygidium of unknown generic and specific relations, occurring in association wit Asaphus Caribouensis, enlarged to three diameters. ASAPHUS ? CURIOSUS ? ..-..- eine Satie a decmee oe seo teen eee eee = eee ane ee 98 Fig. 15. Pygidium associated with Asaphus Caribouensis, enlarged to two diameters, SYMPHYSURUS? ‘GOMDKUSSI ...5.0 - stecece serine =e teste eee maroon ae nee ee 95 Fig. 16. View of the glabella and portions of the fixed cheeks, enlarged to two diameters. CERAURUB frase cccae ee delete os bine se aes cinle sae eee eae eee ee eee 95 Fig. 17. Glabella enlarged to three diameters, to show the granulose surface. PTY CHOPARTA: (1) VANNECTANS Sac ses 5225 otis see oe ee en eee 91 Fig. 18. Glabella and fixed cheeks, enlarged to two diameters. 1.0. 02h @ KE noe aes MEG EE CO OcOSEn Se aa Se asiacee ces aes raSaso apne G-sa eseeeekconccocd 00 Fig. 19. Pygidium associated with the preceding, and also figs. 7 and 12, enlarged to two diameters. ASAPHUBS i enn elnistcinissince sie stin a snes ee ae Nos pete etl Oe ee 00 Fig. 20. Strongly convex pygidium, associated with Asaphus Caribouensis. COLROPRION {MUN UA ao (a's = = <)aiain oom oto mo oil on eal eee raya ae ee ae 85
Fig. 21. Enlargement of a portion of the tube to. four diameters, to show the arching of the striw over the longitudinal ridge on the side opposite the are of curvature. See plate xi, figs. 17, 17a.
Devonian
U. S. Geological Survey: Geology of Eureka District, Plate XII.
T Sinclair & Son, Lith
DEM Gye Od) D2) EE be
ING GAS ON ENSIS ee Sates sina ele mete ae itt Aone ia ee sania a eliem cio'elcteinm|ceima males e\vniaiaiaeis Fig. 1. Ventral ? valve. la. Dorsal ? valve. Natural size.
ISON CHCA LOE RYE Sop ae 55050 COGN SOS RES SUS ORD CSDCED SECU GEEOODRODEeD EE eG CSeeC Ube ECE eee Fig. 2. Ventral valve, from which the surface is largely exfoliated. Natural size.
IDAHO, WEIN 3 S55 Co eSeS ae Sep Ens POSSE S BHEGED DADSC GE Heeb Og AC0D OOH OCdd Son ESo CeO eOOere Fig. 3. Cast of the interior of the dorsal valve, enlarged to two diameters. d. Divaricator muscular sear. ad, Adjustor muscular sears, pa. Posterior adductor sear. aa. Anterior adductor scar. pp. Supposed area of attachment of the posterior parietal muscle. wu. Supposed area of attachment of the walls of the perivisceral cavity. ps. Great pallial sinus. 1s, Lateral branches of the great sinus.
i. Area, that in another specimen shows the inner ramifications of the great sinus.
The various features are rather strongly shown in the figure, but not more so than is justified by the original specimen.
RKENTDIUM DEVONIOCUM so ncles cicisain sees acc cee ncciee ss cissieie claw sale wlnwioeninincle vos clare cece secs
Fig. 4. Ventral valve, enlarged to three diameters. 4a. Cardinal view, showing the areas of the two valves, the foramen, and the medium septum of the dorsal valve.
DVR NOMENON 653546 6555 Soop ceos Sear enocosssoacgoobeee Cope danems soso eres bese oSeec daasos Fig. 5. View of a rather elongate dorsal valve, enlarged to two diameters.
STROBHODONTAR GAL VINE. asics isiocenion sels cgee ses cee seen eae)siinieceiscccelsisceseeltre cacecs Fig. 6. View of ventral valve. Natural size.
SaRMPLORMYNCHUS) CHEMUNGENSIOs = nicis-l--\-\-nclsinwieiosieles se scieeacive=clelssa cinco «= scirinceneace
Fig. 7. View of aspecimen referred to the variety arctostriata. Natural size. 16. View of a specimen corresponding to the typical forms of the species. Natural size.
IERODUCRUSESPECIOSUS (ca steele ae am eim sane ae sa aoa oom mine seine elnino a=) wn aa lain n= lee tema Fig. 8. View showing the surface ornamentation and form of the ventral valve. Natural size.
PRODGCRUS EN AW AG RT U Ste sear alee olden emiejeomciare es elesle mma ame aimee e emma \e “nial ool Fig. 9. Lateral view of a somewhat strongly costate variety, enlarged to two diameters.
STROPHUGDON DASE UNC GIR RACs elena ease iiseemnee nae mae memeiceeesatem ae eelemiclsicl-iinisin\n=le™ e=ism cin Fig. 10. View of ventral valve, showing radiating strie and punctate surface. Natural size.
BTROPHODONTA PERPLANAS << <0 ce aco smcacewalnnce coe so a cnoces on acee ceren=s--=n\==es cones Fig. 11. View of a well-preserved ventral valve, with a portion of the outer surface exfoli- ated.
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PLATE X11I[—Continued.
IPALZOMANON ROEMERI....--. ---- ---- e222 cone ene mone cnn enn on ne eee wane wenn serene ne Fig. 12. View showing the cup-shaped summit and general form. Owing to silicification, the details of the structure are destroyed. “ORTHIS IMBRESSA. 3. Scce see sae ae cota ee nee niae a eee eee a eeile a seine ie ieee im ala —imietak oat Fig. 13. Cast of ventral valve. Natural size.
*CHONETES MACROSTRIATA <.--. 2.25200 <= 202 poo we nnn = oon ne hen = nn renin ee naan Fig. 14. Ventral view and outline of the convexity of an average size specimen. 14a. Same view of an unusually large specimen from which the striated outer surface has been removed, showing the inner punctate surface. 14b. View of ventral valve of asmall, strongly-marked specimen, to which a cardinal spine is attached; 14, 14a, are natural size. 14c. Enlargement of the strie of fig. 14, to show manner of bifurcation. See plate ii, fig. 13. «CHONETES FILISTRIATA..---. .---00 e222 2+ eee en nee cee nnn ee eens cece cee nee ne teen ec eeene
Pig. 15. Ventral view of average size specimen, showing surface strie# and cardinal spines. 15a. Enlargement of the area of the ventral valve, showing the shape of the foramen.
PRODUCTUS HALLANUS...-..---- ---- ---- --- 2-3 2-22 oe ne enn eon cen ee nee wane ee wees Fig. 17,17a. Dorsal and ventral view of average size specimens.
PRODUCTUS LACHRYMOSUS, var. LIMUS Figs. 18, 18a. Lateral and front view of the ventral valve.
PRODUCTUS SUBACULEATUS .--------------- Bee ose Donec a cos Hosa necasoopaL caecuaaneddccanes Figs. 19,19a. Ventral and cardinal views of a specimen from which the outer shell is par- tially exfoliated. 20,20a. Same view of the type of tbe species copied from plate ii, tome xi, Bull, Soc. Geol. de France. The spine bases are stronger than in 19, 19a, but in other speci- mens they are much as in figs. 20,20a, See plate vii, fig. 2.
Page. go
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PRODUCTLUS) SHUMARDIANUS 2s see eos soe meee serie seen enioetessselesaio Sesnosctoc]e SEO SO EEOC Fig. 1. View of the dorsal valve. Natural size.
PRODUCTUS TRUNCATUS .-.. 1.2200 <2 <5 en 00 n= oon 2 cn ne veces een enn ne nn nnn nnn eee e an an ane Fig. 2. View to show the truncated apex of the ventral valve. Natural size.
REYNCHONMDLA) HORSKORDIq.2-)o. === se ae = m= amet = nie om eels etal mele ee ete lee elena Fig. 3. Ventral view of an average size specimen. See plate xv, fig. 6.
ATR Y PASDEBQUAMATA sno. son jeans meee ean nis eee tesee m= steemisians esteem rie eier see ieaieatata te Fig. 4. View of the ventral valve. 4a. Cardinal view to show the small area. Natural size. EREGNON OH ONT AG (Lin) STINT ACOA Ole re eee ete etl li Fig. 5. Dorsal view of a characteristic specimen. Natural size.
ATRYPA RETICULARIS. .--.--.----- - 22-2 + cee oo - oo one ce ne ee ne cen nn enn enn s ewe e en nn cone Figs. 6,6a,6), Ventral, lateral, and dorsal yiews of the small variety mentioned in the text as characteristic of the Niagara formation. | Mir an(GlttOscI FIL eeIDLOLC UIs! oop een bc oE eb babe SCOSS SeQdo Sodas cad Guise Sencocn SSS SSECES Seas ocr Figs. 7,7a. Lateral and ventral views of an average size specimen.
Midian (leti gr nio.w ISO MUN Co 6eds ooSsc no secco cobescisesoas odsace Decors caSsssCnceso saps ooTer : Fig. 8. Dorsal view vf a very striking example of the species,
EPELVON CO NESTE AW (1) NERS ASU NS ISS uote ee ee Figs. 9,9 a,9b. Ventral, lateral, and dorsal views of the ordinary type of the species.
SSD UENE RA Pe ARR A es sn ee rt
Fig. 10. Ventral view of the only specimen obtained, showing the coste and fine radiating striz.
Stauano ony (( C) aie nur ally Se one Senos cen ses SODeBeSScDOS0b RODSbS cde Sonccece Code SS cb cose Beas
Figs. 11, 11a, b. Dorsal, lateral, and ventral views of a specimen from which most of the outer surface is removed. , 13). Ventral valve with a portion broken away, showing the cast of the muscular impression. 13c. Ventral valve of a broad variety of the species, showing the area and small del- tidium in place. See plate iii, figs. 3, 3a, b, 6, 6a.
SPIRIMERA(M.) RARECOST Are cee = nae tain Heme ome tele ees Sisweewalea ed aa'sicleS oem alaitars Fig. 12. View of the partial cast of the dorsal valve of a small shell. See plate iv, figs. 2, 2a.
SPIRIFERA (M.) MAIA -.-....--..--------- BEE Hic es oe oC ene do caaoec oe a tha ooes HasSt concede Figs. 13, 13a. Dorsal and lateral views of an average specimen of the species. See plate iii, figs. 1, 1 a-e. SPIRIFERA (M.) GLABRA, var. NEVADENGIS «<22-0 c- ooo sso nc ca eelene=(= oon see sane ele eles =e Figs. 14, 14a, b. Dorsal, lateral, and front views of the largest and most transverse speci- men in the collection. See plate iii, fig. 5. PEN TAMER US (M.)) COMIS Seo lecinee inna) eae Sete ate ee ee a
Figs. 15, 5a, b. Dorsal, lateral, and ventral views of a transverse, smooth specimen. See plate iii, figs. 4, 7, and plate xv, figs. 5, 5a, ¢.
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Hewonian.
Geology of Eureka District, Plate XIV
- = J a!
Ay
4
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PLATE XV.
Page. REED HON EILIGAS (CAS IUAINTE A feces aa le ei el Pa ele el 153 Figs. 1,14. Front and lateral views of a small subeuboidal specimen. 4,4 a. Ventral and lateral view of an adult shell. GRYPTON GIA CUR CUMIA eee pere clare ee etter etter le ea ee ete lee 163 Figs. 2, 2a, b. Ventral, lateral, and dorsal views of a rather large specimen, enlarged to two diameters. RE YNCHONSELAN? OCCIDENS 22) fers ce ayo aioe tetas alas etal et ew few lam Lette atten) er wena 152 Figs. 3,3.,b. Dorsal, ventral, and lateral views of a typical specimen, enlarged to two diameters. LONGO ANT OM OF) OKO" Seen ge coe coo sobey a Seco cis CSoUnD Ab S56 oos0 ser acu Sees Soc scccinssencsss0s0 159 Figs. 5. Ventral view of a specimen, showing obscure plications towards the front. 5a, 5b. Lateral and ventral views of a rotund, smooth example. See plate iii, figs. 4 and 7, and plate xiv, figs. 15, 15a, b. RHVNCHONELLA) HLORSERORDIs ea onset a rela ale elo al te ee eee le he rmll 152 Fig. 6. Dorsal view of a little smaller example than that shown by fig. 3, plate xiv. ANADONTOPSIS AMYGDALAUFORMIS . - --2- ------ --05 1+ cowees coc n ns woe nne pawns eneehe coness -a== 180 Fig.7. Lateral view of the left valve. 7a. Cardinal view of the two valves united. 7b. Anterior view of the same. PSSA CTA UNS UAH NGS es ea as rt el 172 Fig. 8. Lateral view of the left valve, showing the anterior muscular scar, INU CUIEA SRIESCUENSIS Gael e cle cc are ere se ave el ara aee e =ee ee eint= ol ae eee a tele erate 172 Fig. 9. View of left valve, enlarged to three diameters. GONIOPHORMEPERANGULATA: = scatects saeco eee eee oat em ieenintee ieee ee eis eet 171 Fig. 10. View of left valve, showing the strongly-marked angular ridge. CYBPRICARDINTAMINID ENT Agere aotearoa eet ete alate aie ee teeta eee ate a eee teeta aera 182 Fig. 11. Lateral view of left valve, enlarged to two diameters, to show the characteristic surface markings. See plate v, fig. 14. (EP ORV. Ca UDO BEN. ae eos GAC OoS eaoes inca es ci 9009 Janene BO OU OG BN DS BOTOCAdS Coes SoSH en baS60 165 Fig. 12. Example from Lone Mountain. See plate v, fig. 6. SANGUINOLIMES SVEN TRICOSUS weet eater ret ele alee ale a ate ati ote retell 177 Fig. 13. View of left valve of a specimen preserving the characters of the species. MPGNT VCS ORVO ea se peoc ccce coed pec pon OOnaU S500 COs CueO Gono asctoaseke sno sede csesne ceeded 173 Fig. 14. View of right valve, showing the muscular impressions, enlarged to three diam- eters. 14a. Left valve, similarly enlarged. GRAMMY STAN MINOR yess pote erates tet ae ara lee a ake mr eee eee 174 Figs. 15, 15a. View of right and left valves, enlarged to two diameters. SANGUINOLITES COMBENSIS...----. ee ercien Se mece as «namaste eaort era sea eae SeeeraReeeeees 175
Fig. 16. View of right valve. Natural size.
Devonian
U.S. Geological Survey. Geology of Eureka District, Plate XV
GB Simpson Del T. Sinclair & Son, Lith
12 A IDID) D-\Y 1Ee
PEATYCERAS CONRADLI .....- 2-2. -cnenenncnnwieneens (oon en nen n= een ree = orem nen onsen n= anne Fig. 1. Lateral view, showing the first volution and the sinuosity of the peristome. la. Dorsal views of another example, showing the concentric ridges on the back. EXUOMPHADUS) OREKENSIS) 3 -(o102 0) ommtes cee Sale ee nema la oa elete oleate otal elated
Fig.2. Cast of a medium size shell. 2a. Lateral view of the cast of a large shell, showing the sinuosity in the aperture and the decollation of the inner whorls.
CATTEONEMATOCCIDENTADIBI = sac ce ioc sees sae eee ee eal =e a) eee eects on seen Fig. 3. Lateral view, showing the depressed spine. 3a. Vertical view. The lines on the left side are an accidental feature.
CONOCARDIUMG NEWADENSIS eo some 2 sei =a[= 9 = eee eee eae ee aaa ela teeete Figs. 4,4 a. Two views, showing the character of the species.
LEPERDITIA ROTUNDATA....... .. 2-22 2020 20-2 202 = oon eon ne nen ee ne teen eee ne wane conn none Fig. 5. Enlargement to four diameters of the right valve.
BANGUINOUEDES RIGID US iso siesta gate areal ai ee ae oer ee eee eel are tetera eter Fig. 6. Left valve. Natural size.
StRAPAROLLUS NRWARKENSI Sse hice sai cae eae cinco ae alc emine aaiee is alent = cleeninetcial sociale = setanets
Fig. 7. Basal view. 7a. Summit view of same specimen, enlarged to two diameters.
LLOXONEMA) DUREKENSIS seeessee ete ae ence eee ae ae ee a eat eral aera a ale teeta ote meal el Fig. 8. View of internal cast.
LOXONEMA NOBILE...- .-..-- --- 22 - 2202 cone cone oe enn cece cone coe cee s cone cece cece meee anne Fig. 9. View of internal cast,
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177
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190
190
Deworwrian
U.S. Geological Survey: Geology of Eureka District, Plate XVI
G B. Simpson Del
- i = il aa ~ , \ . ’ ‘
PLAT Hh ZV.
(PEAY SCHISMAIMOC OVE oe se celen se sateen etre eee tela tee Pept acoso csecuscassceccoscs Saneen Figs. 1, ia, 1b. Summit, lateral, and basal view of a small specimen. Natural size. le. Longitudinal section of a larger shell. METOPTOMAS UD EVONICAW ce ser coca en cca teeainerioe close meats tee ene en eee eee aoe
Figs. 2,2a. Lateral and anterior view of the type specimen.
PLATYSCHISMA ? AMBIGUUM..---- .<--0- 220-00 0--n0- ones woe n en onan enw ree conn enw eees cones 5 Figs. 3, 3a. Lateral and summit view of a silicified specimen.
BEYRICHTA® (E>) \OCCIDENTADIS (eos sees ane meetin eee ie te ele nee eee eee Fig.4. Large size left valve, enlarged to four diameters 4a. Enlargement of a young specimen (1™™) in length, to show the unisuleate char- acter at this stage of growth, x 12.
VOY AE ee i Doe a og oe ESS Ga gene sooSe a Somes So goSeeD Hoee Ect DaseasSoseS postcns codessodesce Fig. 5. View of the glabella of a medium size specimen. 5a, 5b. Dorsal and lateral views of a medium-size and large pygidium. 5e. Enlargement of a portion of the surface of 5b, to show the punctate character of the test.
BELLEROPHON) PERPUR KA se slem 2 ale wes leis miele tela aal se Pe eal ote a) laa eater S Fig.6. Transverse section, showing the deep, open umbilicus and flattened whorls. 6a. Dorsal view, showing the dorsal ridge and the direction of the stria. 6b. Longitudinal section, showing the closely coiled whorls.
CyrTOCERAS NEVADENSIS ..-- .--- FERRIC ICTIO OAR U ode sac Sarn Sao uOn Rona SHODS aoe Se aeene sees Fig.7. Lateral view, showing the depth of the chambers and the curvature of the tube. 7a. Ventral view of the same, with the surface striw preserved.
GOMPHOCERAS|SUBOVIHORME ~coe on once as cee melon seat aeceen ome cen teniaams neimospesscsoasesec Fig.8. Ventral view, showing the chamber of habitation, air-chambers, and a portion of the siphuncle exposed by the weathering of the specimen. 8a. Lateral view of the same.
BELLEROPHON COMBSL cc. ooc- = ooo eee eecesis= === <= -/aenlonae PcO chro Sse ecodon sect SCO ASE S Figs.9,9a. Lateral and front view, to show the form of the species.
GONTATITESIDESEDERATUS oiniste mma am mete mateo = 2) ate ete lot iol eae) otto al etate inl etalsferaie aie reas Fig. 19. Lateral view of a specimen preserving a portion of the surface strie on the inner volution.
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Hewonian
U.S. Geological Survey. Geology of Eureka District, Plate XVII
G B Sampson Del
Carbomiterows
U.S. Geological Survey. Geology of Eureka District, Plate XVIE.
|
—— a G.B Simpson Del T Sinclair & Son, Lith
IBID) DOA IIE Ee
TIN GULAGSLYUILOIDRA ee cemel ane smoaainecc.or oc won cinwaslcccneacc ccsses Been costes So ceeee eae
Fig.1. View of a specimen from the lower portion of the Carboniferous formation, north of Pinto Peak.
DISCINADN E WiBIERE Vikse oe a see rose cas poco cee ciccc ase cancec succeed so teek ctcetoe snes access
Figs. 2, 2a. Dorsal and ventral valves of a form from the shale in Secret-cafion-road Cafion, doubtfully referred to this species, enlarged to two diameters. 3. Dorsal valve from Richmond Mountain. Natural size.
SEL ERE AG MALLE Wee ene ee ete eee a aae setter Sate eines niet wives lnraisinialc snislccels eile ste s,c.cie siemicen sles scice
Figs. 4, 4a. Dorsal and ventral views of the average size specimens found at Richmond Mountain.
DED ARES URS UE Ae ey ene ae eee olnieie ales Siem a cineln cia mice a wa icieiaw else leis pele odie aan eae ae ewan
Fig.5. Dorsal view of a specimen from Coal Hill, Pancake Mountains, White Pine County, Nevada.
CEMARGEHORTA C OOPERENSIS) ose men see ee ee inn sane lelaeici sia onic Menwle= ce caicis sie A> - oman Fig.6. Ventral view of a specimen from Richmond Mountain.
PS BER DEE RAR ANNINGE CLUAENS siete es arte la wie ene aaa sat nlwlaiatelale\= miele talala a'ciolaisintnian! eles > «ina = 6=) o1nteieieleien ==
Figs.7, 7a. Dorsal and ventral views, showing the rounded cardinal extremities, and the coarse plications,
RERVINCHONE ZANE UH KIGNSIS =. stele saaiee cesta = aia a ele csinellela'a eve ntatelelstalal~'ela:almiaiels eoi=\vlne wicinivteinininwieo =
Fig. 8. Lateral view of a specimen which is slightly crushed. 8a. Ventral view of the same. 8b, c. Ventral and dorsal views of a smaller example.
iNnnaniis) IRORESH Et 55.22 sear Ses oS Soone a eecoes SoeEboonessoood= Sobedose pbs Sae soesaeiedod cee sees Fig.9. Dorsal view of a specimen from the cafion north of Pinto Peak. 9a. Lateral view of the same.
(Saag TOI. CISTI TO Cp oe os BAS CO b Ca DEER Code Ser SE eased e CEO COE RSOD COO MO So IOOCO DS SeCOmeseer Fig. 10. View of a ventral valve, from Richmond Mountain.
(S/DERTIAIIE A, DIMMED SV IS) eS o5 9566 coe ors cope ee es Eee aS 59 ca Scoe Sees SHE Hee oHeeeeoesees ees Fig. 11. View of a ventral valve, from which the outer shell is largely removed.
(STRATOS, CIPI GY en meg coceos Socoos SEE SEO BOC ESS OSCE Ss BEDS OSUDSoSaes Coes eosEeereecps Fig. 12. Dorsal view of a specimen from the Chester limestone of Chester, Ill. Introduced for comparison. 13. Same view of a specimen from the upper portion of the Carboniferous Group in the Eureka District. The spine bases are not shown in the figures, although quite prominent on the shells from each locality.
SItTRMP TOR EAN © HES (ORION IS UREA senna seeee saa lancet emateletetnela= nislceninleini= sais alent sia n'=eln merino = Fig. 14. View of a strongly striate form, found at Richmond Mountain.
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PLATE XVIIJ—Continued.
PLEUROTOMARIA NODOMARGENATA: 6 a aieiemiem ae nei ae lel a oh oe a te at
Fig. 15. Enlargement to three diameters of a typical specimen, from the lower portion of the Carboniferous Group.
METOPTOMA PEROCCIDENS © << -<2 2 0-200 weno wn wee ene eee ees wens conse owner acs ssen ee aees ee Fig. 16. Summit view, showing the outline and the radiating dark lines and fine concentric strie. QORTHOCERAS /RANDOULPHENSIS Mea jaja)ee meals eee ele ee ee ee See mpcdos Fig. 17. View of a crushed fragment of the tube.
yan oy ss Oso. ONOH Ch Soo 6 cogcte ceciboe GaSe Co UaO Set eSee bys s5c Dec on owas Hao edoo ConpSESsosse Fig. 18. View of broken specimen, showing the surface characters and general form.
EUOMPHALUS (S.) SUBRUGOSUS. ......---. ---- .----- --- 2-2 none conn ne =e ncansacc socoscomeccos Fig. 19. Summit view of a small characteristic specimen.
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IPMG MID) QC Ils
AVICULOPECTEN AEKENIS) pesianislemio cele sma (snee sete an atte ee ae et eee ee te Fig. 1. Left valve of an average size specimen. la. Right valve of a smaller shell, in which the sinus is deeper beneath the anterior ear. AVICULOPECTEN “EUREKENSIS: «sso eae o22 =< see a oac oe eee saisce se ce asin ae oe ee eee Fig. 2. View of a left valve compressed laterally. 3. Left valve with the anterior ear restored in outline. Shell flattened by compression. AVICULOPECTEN, HAGUED 22 ison - clos seec en ecine Suits caysneenieins ase eee een a eee eee Poe Fig. 4. Left valve with the outline of the posterior basal margin restored from the matrix, the margin of the shell having been broken away. MYALINA \NEMBESIS=. soo. an speisssoasiecni tense ac. saci onis aaa e Soe e Sees ee eae ee eee eee
Fig. 5. Left valve with the beak broken away. See plate xxii, fig. 7. MYALINA CONGENERIS . S Gano Sosa COU SSO One DSN. Goan aaaose Sete poo coosibe assscche Fig. 6. View of the snares? left caine collected. It is about inreafourths of ahs size of the largest specimen. See plate xxii, fig. 10. STREBLOPTERIA |GIMILIS'53-.!hscs seicsc ee ee oa as os eee ooo eae oe enon en se ee So eee Fig. 7. Right valve. See plate viii, figs. 4, age
MODIOLA.?. NEVADENSIB 2 <vic\-- oc «cece co seen cones ce soeien aces ateonvences dececmuccleorese cee Fig. 8. View of a somewhat compressed specimen of the right valve.
SANGUINOLITES'? (NAINTA 322% 232 3-25 a2 sos e ee alee es comes Sore oe eee ee eee ee ee eee Fig. 9. Right valve.
PTERINEA "PINTOENSIS cos asics Vos oo siasdece sce cisaces dene ciecse osceiac eae ctecarieaecieaecieeneaa eae Fig. 10. View of left valve, enlarged to two diameters.
PINNAVINEXPEOTANS moa cmeecisscessecisesenceensiceneseaeesnesesseae oe ene e ence ce tannes once cece Fig. 11. View of posterior half of left valve.
227
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POWs
fe
mM
arbor
~ v
Geological Survey
Geology of Eureka District. Plate XIX
>
U.S.
clair & Son, Lith:
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MODIOMORPHA AMBIGUA oo oo eeiw eee eae ene eee eee eee nlase en ston eate ane seein waeeloe ee Fig. 1. Left valve of a slightlyorashed specimen.
MODIOMORPHA ? PINTOENSIS eo estene soe ses cleo ne ona (nee elea ale aistele eel are tall Fig. 2. View of the specimen used in the description.
MODIOMORPHAG (DESIDERATA Sen pines (neal oleae leetalesiaeelole mista seta elle ae le Fig. 3. Anterior portions of the right and igmeaicaes as ss dliog appear on a fragment of lime- stone.
GRANIIYSTAVHANNIBATLENSIS( seo) osclenccaclee = -isen semen cele tee teen ee eee ate eee eee Fig. 4. View of a right valve which is a little compressed.
GRAWOEYSTAV AR CUATAQ=e = ooo cees saaelor es soso ieee eee en ese ieee Bed ete cosono assess Fig. 5. Right valve found in the same beds with the pmoneding species.
RANGUINOGLUKS) A OUUS nme ecee seee ema ens ee ete eee ese ate moe eee eee ee lee aielnetreleteteetettete Fig.6. Elongate form ofright valve, very closely allied to the type examples of the species. 7,9. Right and left valves of two shells that vary in form from fig. 6.
SCHIZODUSVCUNEATUB mcnislesienicistomtenia einioisie Seicicr sein stateless tate ee ete ate eet ere otal eto late eet ete Fig. 8. View of the right valve.
SANGUINOLITES RETUSUS ..-.----..cceesecees 2200+ -- arSnengosodordce sac sasces Fig. 10. Right valve. The radiating ridges of the sirdben slaps Beer strong in the figure.
SANGUINOLITES SIMPLEX -.< cavisee sive meres see ietee ateteeinaisl se ate ee ate tae a eae ee tree Fig. 11. View of the right valve.
SY USER ODOOLA UU CL ISIC EAR es Gree pep BS SG UCD 2 SO00SS SCaOSO asc SodSte casted cones Ssecs6e Fig. 12. Right valve showing the strong radiating lines of the umbonal slope.
os anP (OO) fs) 6 00 Ce sere Seca SEOSCOBOOO SOSSOUBOECSGS SASS HaSoOSE Nanab Soonet SenocoSS CREO SSTOOS Vig. 13. View of a small specimen of the left valve, with portions restored in outline,
INU GUTAG ENS UGA RIG otal crete tees eee lett fete tae teeta esausseces Fig. 14. Left valve, showing general form and the tine, concentric surface striz.
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Carboniferous
U.S. Geological Survey. j Geology of Eureka District. Plate XX
G3 Simpson Del T. Smclair k Son
U.S. Geological Survey.
CDW del
~Olenellus and Hingula,
PLATE XXII.
OLENELLUS) HOWELED << 0c cccuiscoc'so ne 3-00 cose nse enarisren ne sees eameenice rinrin= so =scee/o=5=
Fig. 1. Outline of the smallest head of this species discovered. Natural size.
2. Head showing the anterior position of the genal spines, 9 9, and the angles of the posterior margin, «x, extravagantly developed. The difference in the length of the ocular ridges of the right and left side is also very marked. Natural size.
. The smallest individual in which the posterior course of the facial suture was observed. The outline of the head is much like that of fig. 1. Natural size.
4, Form intermediate in contour of head, between figs.2 and3. gg, Genal angles and spines; #2, angles of the posterior margin. Natural size.
. The eyes in this specimen are no longer pedunculated or united to the glabella by an ocular ridge, and the genal angles are more posterior. The course of the facial suture in front of the eye is also seen for the first time. Natural size.
6. Example in which the genal angles are in the same position as in the adult indi- vidual in species of the genus. The eyes are more embryonic in character than in the preceding example. Natural size.
7, Narrow form, with the eyes of the adult type, and having the genal angles carried forward, as in the younger individuals, 1, 3,5. Natural size.
8, Broader and more common form showing the same peculiarities as fig. 7. Natural size.
9. The right and left sides are irregularly developed, the genal spine on the left side being more anterior in position. The course of the facial suture is traced in accordance with its position, as observed in fig. 6. Natural size.
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ao
QOLENELLUS ASAPHOIDES Emmons. ...--.-.-----.----- -----+ ---+------- seb ode Shoo ose aaa DSIOD Fig. 10. Embryonic form, showing the circular outline, the genal spines in close proximity to the facial suture, and the interocular spines. Enlarged to 3.5 diameters. (After Ford.)
11. Another phase of the development of this species, succeeding, with probably in- termediate forms, fig. 10. The posterior of the genal spines, gg, and the sutures cutting the posterior margin at the angles, xx, are comparable to the same in fig. 3.
Enlarged to five diameters. (After Ford.) 12. Normal adult type of head of this species, enlarged totwo diameters. (After Ford.)
OLENELLUS GILBERTI.. ..-.------ --- 022 22 o ne ene en ee eee eee nee rene ane te eees cone raceee Fig. 13. Small head, natural size, for comparison with figs. 2, 3, etc., of its associate species, O. Howelli. A large head is figured on plate ix, fig. 16. 14. Narrow form of head, that shows the angles in the posterior margin, «, slightly developed. Natural size. (After White.)
PARADOXIDES KJERULFI Linnarsson...--. .----- --20 2-22 22 enn cece cones cone cee ene eee e enee
Fig. 15. Outline of head showing the position of the genal angles and angles of the pos- terior margin, #7, with the interocular spine; also the ocular ridge (a) uniting the glabella and eyes. (After Linnarsson.)
OLENELLUS HOWELLI .... .... ---- 222 22 ee ne ee ee ne ee eee ne ne ee ne ee ce en ce ete ne ee ee eee eens 16. Outline of hypostoma found associated with this species. Enlarged to three diam- eters.
17. Free cheek found detached from the fixed cheek. The direction of the suture in front of the eye is well defined, s; its direction posteriorly may be along the line of fracture, 0 0, but it is impossible to satisfactorily determine it. If, as in fig. 6, it would follow the dotted line, o .
PLATE XXI—Continued.
Page. LINGULA. ELDER. o5sc0 5255/5250 che stise ee Lae nled eee ae ae eee eee eee oe ee eee 111 Fig. 18, Outline of the interior of the dorsal valve, showing the muscular and vascular markings: d. Divaricator muscular scar. ad, Adjustor muscular scars, pa. Posterior adductor scars. aa. Anterior adductor scars, xa. Track of advance of the muscular scars. s. Great pallial sinuses. ps. Posterior course of the latter. o. Inner ramifications of the sinuses. (After Whitfield. )
More ope’ WA RGU AS Boos coocnd CESoneCHE Saoscesesnecn sec Sac ese ORO ChED Ssescocceoeonert backed] 109 Fig. 19. Outline of the figure of this species on plate xiii, fig. 5. The corresponding parts are lettered, as in fig. 18. F;
TUINGUDAVAREUNIS: cose sieasisite ee clare coe an siete arlene ra eee ena Re a ere eee SBD ECA SOE ME cone aoe 111
Fig. 20. Dorsal valve, reduced, after Hancock’s figure. Lettering, the same as in figs. 18 and 19.
1PM BN AW ID)» Seo OIE
NUCULA "LEVATIFORME. .22 Sottses = So eee eee eee eee
Fig.1. Right valve. la. Outline. Natural size.
SCHIZODUS' PINTOENSIS ; -2%.5<< 50525 o5 5,52 = Se cfeds aos ane aoe eneesseins aaa = Sonena coeeetienee nee eee Figs. 2, 2a. Right and left valves. Natural size. SCHIZODUS CURTIFORME....-..-......- ABS S EM OBO OHO CO ODOO EDUC OOO SOEUR Om aCesaCSEE Secocsss
Fig. 3. Right valve. Natural size. 3a. Profile view of fig. 3. CARDIOLA T FILICOSTATA.§ 222.52 -\c55 20-0 eas sso ceene ences soe Fig. 4. Left valve, enlarged to two diameters. 4a. Anterior view of fig. 4. SCHIZODUS DEPARCUSE oo seeeienee eines anes eeennennieee eet
Fig. 5. Right valve. Natural size. 5a. Posterior profile view of fig. 5.
te ewe wees Beene woes wees cows cere
Sta) ASTON .Y (6107 1 Oe Se eee a ere oSROn rs SOS SRO Aint Se a5. 505 CODbSn.Gocnne Cece cccrcacad cose os Fig. 6. Left valve. Natural size. 11. A more transverse right valve. Natural size. MYVALINAU NEMESIS) 22 once )oenjenacieenciasa Celialescowalsamcecitene a saeae cen eae ate n eee eee Fig. 7. A right valve. Natural size. See plate xix, fig. 5.
MVATINA NESSUS fee corc «cee elec einetalnm ene viecacjemeece sae ania ete nen seete adam ae ee ee aaa eee Fig. 8. A large right valve. da. A smaller right valve, showing the anterior margin. ISDMONDIA) 1) GIR COLARIS fers oete mee sete eee lee aia a ee le ee Fig. 9. Cast of left valve. Natural size.
MYALIVA' (CONGENERIS = .cce- cece ace savseciesoresisseeseeseeee Fig. 10. Right value. Natural size. See plate xix, fig. 6.
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UNITED STATES GEOLOGICAL SURVEY
PALEONTOLOGY
OF THE EUREKA DISTRICT PL.
XXII
CARBONIFEROUS
PLA DE XT.
BELLEROPHON MAJUSCULUS « ...--- ccce eoccce cncnee woe cnnnee ence ns coc nce = cn cens cesses cecece Fig. 1. View of aperture, callus, and body-whorl. Natural size. la. Lateral view of fig. 1.
ORTHOCERAS EUREKENSIS....-.---------+--2- 2-02 ses eee eee ee eee teen ee eee ee paces cneco: Fig. 2. Lateral view, showing curvature of the chambered portion of the tube. Natural size.
2a. One of the septa, with the small siphuncle and areole about it.
EDO EU TEES | CARBON ARUAGstotere e watet clatter te tale ta eee Soecoes Fig. 3. Enlargement to three diameters of the type specimen.
CONULARIA MISSOURIENSIS .... ..--5--- 2200 scence oone cece ee pa oscoodersocecs mobsnscoonececs Fig.4. A crushed specimen, Natural size.
MACRODON) SIAMELTONAD oe -aeaeele oases eas selvesise ces nceeeme item ccne tee see Fig. 5. Cast of right valve. Natural size.
5a,b. Casts of left valve. Natural size. 5e. Enlargement of the surface of another specimen,to show the characteristic radiating and concentric lines.
EDMOND IAW MED ON fee tets ete eet al erate new tea el a Fig. 6. Right and left valve. Natural size.
SANGUENOEYTES) STRIATUS ie ace eee eae nase se eaela eee ane tee es eee nas ase e=heee saa leme sales Fig. 7. Left valve. Natural size.
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UNITED STATES GEOLOGICAL SURVEY PALEONTOLOGY OF THE EUREKA DISTRICT PL. XXIII
CARBONIFEROUS
IBY DAUD) DCI 6
TiOXONEM AU BEDA sae aise = ele saat ee eee ae ee ee eetaee tee ee eee eee ere Figs. 1,1 a. Anterior and posterior sides of the same shell. Natural size.
PLEUROTOMARIA\NEVADENSIS nae 1s meee tes atstare etait alae ee eae i Fig. 2. Anterior view of a slightly crushed specimen that is denuded of most of the outer shell.
2a. Enlargement of a piece of the outer surface of the shell, to show the peripheral band and surface characters. PLATYOSTOMA INORNATOMe sp see ye 2 = este ne oie ool sien te el oieiane eaten ere Figs. 3,3a. Anterior and posterior views of the cast. Natural size,
GRINEITHIDES FOR TEOCRM ase ie are ohana oer ala weet a ole Fig. 4. Central portions of the head. Natural size. 4a. Pygidium. Natural size. 4b. Right free cheek. Natural size. MUCH OD ONG (G9) ONGNCACT IS era alate ea Ne Fig. 5,5a. Right and left valves. Natural size.
BELEEROPHONEMATUSC UUUS emai encase eee aie iota nee ete ee eres Fig. 6. Dorsal view of a large specimen. A cross-section of the body-whorl of this speci- men is shown in the text. See plate xxiii, figs. 1, la. : IPFA TY GERAS HPIS Ol eae s a ere erate ee a ee ae ao lee eee leo Fig. 7. Dorsal view. Natural size. 7a. View of the side denuded of the shell. Natural size, 7b. The other side of the same specimen, preserving the outer shell. WW Cor overs 0H OH) IS oso Se cnowad a6 2am aooRse dooce sceceos SSog ns eS Sosa I sossses ae sosossece Fig. 8. Anterior view of the specimen mentioned in the text. Natural size.
PLAT Y CRRAS(OCCIDENS= sem seat oieeesacte sista iets esos ee aie int ate tee ine ee eet
Fig. 9. Dorsal view of a small shell, enlarged to two diameters. 9a. Lateral view of another shell similarly enlarged.
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UNITED STATES GEOLOGICAL SURVEY PALEONTOLOGY OF THE EUREKA DISTRICT PL. XXIV
r