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BULLETIN

UNITED STATES

GEOLOGICAL SUIIVEY

No. l.OG

THE CGLQKADO FORMAT ION AND ITS DfVJ^UTKBKATE

.FAUXA 

W.ARTTTXOTOTsT

G O V E R N .11 J-i K T P R i X T I X t.!- () F PIC E

1SM3

LIBRARY CATALOGUE SLIPS.

United States. Department of the interior. (U. S. geological survey). 

Department of the interior | | Bulletin | of the | United 

States | geological survey | no. 106 | [Seal of the department] | 

Washington | government printing office | 1893

Second title: United States geological survey | J. W. Powell, 

director | | The | Colorado formation | and its | invertebrate

fauna | by | Timothy W. Stanton | [Vijrnctte] | 

Washington | government printing office | 1893 

8°. 288pp. 45 pi.

Stanton (Timothy W.).

United States geological survey | J. W. Powell, director | |

4 The | Colorado formation | and its | invertebrate fauna | by |

5 Timothy W. Stauton | [Vignette] |

S Washington | government printing office | 1893

3 t 8°. 288pp. 45 pi.

^ [UNITED STATES. Department oj the interior. (U. S. geological survey), 

Bulletin 100.]

ji United States geological survey | J. W. Powell, director | |

s The | Colorado formation | and its | invertebrate fauna | by |

| Timothy W. Stanton | [Vignette} |

2 Washington | government printing office | 1893

» 8°. 288pp. 45 pi.

£ [UNITED STATES. Department of the interior. (U. S. geological survey).

£ Bulletin 106.]

H

 [Bulletin No. 106.]

The publications of the United States Geological Survey are issued In accordance with the statute 

approved March 3, 1879, which declares that 

"Thepublications of the Geological Survey shall consist of the annual report of operations, geological 

and economic maps illustrating the resources and classification of the lands, and reports upon general 

and economic geology and paleontology. The annual report of operations of the Geological Survey 

shall accompany the annual report of the Secretary of the Interior. All special memoirs and reports 

of said Survey shall be issued in uniform quarto series if deemed necessary by the Director, but otherwise in ordinary octavos. Three thousand copies of each shall bo published for scientific exchanges 

ami for sale at the price of publication; and all literary and cartographic materials received in exchange 

shall bo the property of the United States and form a part of the library of the organization; and the 

money resulting from the sale of such publications shall be covered into the Treasury of the United 

States."

On July 7,1882, the following joint resolution, referring to all Government publications, was passed 

by Congress :

"That whenever any document or report shall be ordered printed by Congress, there shall be printed, 

in addition to the number in each case stated, the 'usual number' (734) of copies for binding and 

distribution among those entitled to receive them."

Except in those cases in which an extra number of any publication has been supplied to the Survey 

by special resolution of Congress or has been ordered by the Secretary of the Interior, this oilice has 

no copies for gratuitousidistribution. 

ANNUAL REPORTS.

I. First Annual Report of the United States Geological Survey, by Clarence King. 1880. 8°. 79pp. 

1 map. A preliminary report describing plan of organization and publications.

II. Second Annual Report of the United States Geological Survey, 1880-'81, by J. "W. Powoll. 1882. 

8°. Iv, 588pp. 62 pi. Imap.

in. Third Annual Report of the United States Geological Survey, 1881-'82, by J. "W". Powell. 1883. 

8°. xviii, 564 pp. 67 pi. and maps.

IV. Fourth Annual Report of the United States Geological Survey, 1882-'83, by J. "W. Powell. 1884. 

8°. xxxii, 47i) pp. 85 pi. and maps.

V. Fifth Annual Report of the United States Geological Survey, 1883-'84, by J. "W. Powell. 1885. 

8°. xxxvi, 469 pp. 58 pi. and maps.

VI. Sixth Annual .Report of the United States Geological Survey, 1884-'85, by J. "W. Powell. 1885. 

8°. xxix, 570 pp. 65 pi. and maps.

Vn. Seventh Annual Report of the United States Geological Survey, 1885-'86, by J. "W. Powell. 1888. 

8°. xx, 656 pp. 71 pi. and maps.

VIII. Eighth Annual Report of the United States Geological Survey, 1886-'87, by J. "W. Powell. 1889. 

8°. 2 pt. xix, 474, xii pp. 53 pi. and maps; 1 p. 1., 475-1063 pp. 54-76 pi. and maps.

IX. Ninth Annual Report of the United States Geological Survey, 1887-'88, by J. W. Powell. 1889. 

8°. xiii, 717 pp. 88 pi.'and maps.

X. Tenth Annual Report of the United States Geological Survey, 1888-'89, by J. "W. Powell. 1890. 

8°. 2 pt. xv, 774 pp. 98 pi. and maps; viii, 123 pp.

XI. Eleventh Animal Roportof the United States Geological Survey. 1889-'90, by J. "W. Powell. 1891. 

80. 2pt. xv, 757pp. 66 pi. and maps; ix, 351 pp. 30 pi.

XII. T wel fth Annual Report of the United States Geological Survey, 1890-'91, by J. "W. Powell. 1891. 

8°. 2 pt. xiii, 675 pp. 53 pi. and maps; xviii, 576 pp. 146 pi. and maps.

XIII. Thirteenth Annual Report of the United States Geological Survey, 1891-'92, by J. W. Powell, 

1893. 8°. 3pt.

MONOGRAPHS.

I. Lake Bonnevillo, by Grove TCarl Gilbert. 1890. 4°. xx, 438 pp. 51 pi. 1 map. Price $1.50.

II. Tertiary History of the Grand Canon District, with atlas, by Clarence E. Button, Capt. U. S. A. 

1882. 4°. xiv, 264 pp. 42 pi. and atlas of 24 shpots folio. Price $10.00.

I
II ADVERTISEMENT.

HI. Geology of the Comstock Lode and the "Washoe District, with atlas, by George F. Beclcer. 1882. 

4°. xv, 422 pp. 7 pi. and atlas of 21 sheets folio. Price $11.00.

IV. Coinstock Mining and Miners, by Eliot Lord. 1883. 4°. xiv,-451 pp. 3 pi. Price $1.50.

V. The Copper-Bearing Rocks of Lake Superior, by Koland Duer Irving. 1883. 4°. xvi, 464 pp. 

151. 29 pi. and maps. Price $1.85.

VI. Contributions to the Knowledge of the Older Mesozoic Flora of Virginia, by William Morris 

Fontaine. 1883. 4°. xi, 144 pp. 541. 54 pi. Price $1.05.

VII. Silver-Lead Deposits of Eureka, Nevada, by Joseph Story Curtis. 1884. 4°. xiii, 200 pp. 16 

pi. Price $1.20.

VHI. Paleontology of the Eureka District, by Charles Doolittle Walcott. 1884. 4°. xiii, 298 pp. 

241. 24 pi. Price $1.10.

IX. Brachiopoda and Lamellibranchiata, of the Earitan Clays and Greensand Marls of New Jersey, 

by Robert P. Whitfleld. 1885. 4°. xx, 338 pp. 35 pi. 1 map. Price $1.15.

X. Dinocerata. A Monograph of an Extinct Order of Gigantic Mammals, by Othniel Charles Marsh. 

1886. 4°. xviii, 243 pp. 561. 56 pi. Price $2.70.

XI. Geological History of Lake Lahontan, a Quaternary Lake of Northwestern Nevada, by Israel 

Cook Russell. 1885. 4°. xiv, 288 pp. 46 pi. and maps. Price $1.75.

XII. Geology and Mining Industry of Leadville, Colorado, with atlas, by Samuel Franklin Emmons. 

1886. 4°. xxix, 770pp. 45 pi. and atlas of 35 sheets folio. Price $8.40.

XIII. Geology of the Quicksilver Deposits of the Pacific Slope, with atlas, by George F. Becker, 

1888. 4°. xix, 486 pp. 7 pi. and atlas of 14 sheets folio. Price $2.00.

XIV. Fossil Fishes and Fossil Plants of the Triassic Rocks of New Jersey and the Connecticut Valley, by John S. Newberry. 1888. 4°. xiv, 152 pp. 26 pi. Price $1.00.

XV. The Potomac or .Younger Mesozoic Flora, by "William Morris Fontaine. 1889. 4°. xiv, 377 

pp. 180 pi. Text and plates bound separately. Price $2.50.

XVI. The Paleozoic Fishes of North America, by John Strong Newberry. 188D. 4°. 340 pp. 53 pi. 

Price $1.00.

XVII. The Flora of the Dakota Group, a posthumous work, by Leo Lesquereux. Edited by F. H. 

Knowlton. 1891. 4°. 400pp. 66 pi. Price $1.10.

XVIII. Gasteropoda and Cephalopoda of the Raritan Clays and Greensand Marls of New Jersey, 

by Robert P. Whitfleld. 1891. 4°. 402pp. 50 pi. Price $1.00.

XIX. The Penokee Iron-Bearing Series of Northern Wisconsin and Michigan, by Roland D. Irving 

and C. E. Van Hise. 1892. 4°. xix, 534 pp. 37 pi.

XX. Geology of the Eureka District, Nevada, with atlas, by Arnold Hague. 1892. 4°. 419 pp. 8 pi. 

In press:

XXI. The Tertiary Rhynchophorous Colcoptera of North America, by Samuel Hubbard Scudder.

XXII. A Manual of Topographic Methods, by Henry Ganuett, chief topographer.

XXIII. Geology of the Green Mountains in Massachusetts, by Raphael Pmupelly, J. E. Wolff, 

T. Nelson Dale, and Bayard T. Putnam. 

In preparation:

 Mollusca and Crustacea of the Miocene Formationa of New Jersey, by R. P. Whitfield.

 Saui-opoda, by O. C. Marsh.

 Stegosauria, by O. C. Marsh.

 Brontotherulaj, by 0. C. Marsh.

 Report on the Denver Coal Basin, by S. F. Emmona.

 Report on Silver Cliff and Ten-Mile Mining Districts, Colorado, by S. F. Emmons.

 The Glacial Lake Agassiz, by Warren Upham.

BULLETINS.

1. On Hypersthene-Andesite and on Triclinic Pyroxene in Augitic Rocks, by Whitman Cross, with a 

Geological Sketch of Buffalo Peaks, Colorado, by S.F. Emmons. 1883. 8°. 42pp. 2 pi. Price 10 cents.

2. Gold and Silver Conversion Tables, giving the coining values of troy ounces of fine metal, etc., computed by Albert Williams, jr. 1883. 8°. 8pp. Price 5 cents.

3. On the Fossil Faunas of the Upper Devonian, along the meridian of 76° 30', from' Tompkins County, 

New York, to Bradford County, Pennsylvania, by Henry S.Williams. 1884. 8°. 36pp. Price 5 cents.

4. On Mesozoic Fossils, by Charles A. White. 1884. 8°. 36 pp. 9 pi. Price 5 cents.

5. A Dictionary of Altitudes in the United States, compiled by Henry Gannett. 1884. 8°. 325 pp. 

Price 20 cents.

6. Elevations in the Dominion of Canada, by J. W. Spencer. 1884. 8°. 43 pp. Price 5 cents.

7. Mapoteca Geologica Americana. A Catalogue of Geological Maps of America (North and South), 

1752-1881', in geographic and chronologic order, by Jules Marcou and John Belknap Marcou. 1884. 

8°. 184 pp. Price 10 cents.

8. On Secondary Enlargements of Mineral Fragments in Certain Rocks, by R. D. Irving and C. R. 

Van Hise. 1884. 8°. 56 pp. 6 pi. Price 10 cents.

9. A report of work done in the Washington Laboratory during the fiscal year 1883-'84. F. W. Clarke, 

chief cheuiiat. T. M.Chatard, assistant chemist. 1884. 8°. 40pp. Price 5 cents.
ADVERTISEMENT. Ill

10. On the Cambrian Faunas of North America. Preliminary studies, by Charles Doolittle Walcott. 

1884. 8°. 74 pp. 10 pi. Price 5 cents.

11. On the Quaternary and Recent Mollusca of the Great Basin; with Descriptions of New Forms, 

by R. Ellswortb. Call. Introduced by a sketch of the Quaternary Lakes of the Great Basin, by G. K. 

Gilbert. 1884. 8°. 66pp. 6 pi. Price 5 cents.

12. A Crystallographic Study of the Thiuolite of Lake Lahontan, by Edward S. Dana. 1884. 8°. 

34 pp. 3 pi. Price 5 cents.

13. Boundaries of the United States and of the several States and Territories, with a Historical 

Sketch of the Territorial Changes, by Henry Gannett. 1885. 8°. 135 pp. Price 10 cents.

14. The Electrical and Magnetic Properties of the Iron-Carburets, by Carl Barus and Vincent 

Strouhal. 1885. 8°. 238 pp. Price 15 cents.

15. On the Mesozoic and Cenozoic Paleontology of California, by Charles A. White. 1885. 8°. 33 pp. 

Price 5 cents.

16. On the Higher Devonian Faunas of Ontario County, New York, by John M. Clarke. 1885. 8°. 

86 pp. 3 pi. Price 5 cents.

17. On the Development of Crystallization in the Igneous Rocks of Washoe, Nevada, with notes on 

the Geology of the District, by Arnold Hague and Joseph P. Iddiugs. 1885. 8°. 44 pp. Price 5 

cents.

18. On Marine Eocene, Fresh-water Miocene, and other Fossil Mollusca of "Western North America, 

by Charles A. White. 1885. 8°. 26 pp. 3 pi. Price 5 cents.

19. Notes on the Stratigrapby of Califoruia, by George F. Beckor. 1885. 8°. 28 pp. Price 5 cents.

20. Contributions to the Mineralogy of the Rocky Mountains, by Whitman Cross and W. F. Hillebrand. 1885. 8°. 114 pp. 1 pi. Price 10 cents.

21. The Lignites of the Great Sioux Reservation. A Report on the Region between the Grand and 

Moreau Rivers, Dakota, by Bailey Willis. 1885. 8°. 16 pp. 5 pi. Price 5 cents.

22. On New Cretaceous Fossils from California, by Charles A. White. 1885. 8°. 25 pp. 5 pi. 

Price 5 cents.

23. Observations on the Junction between the Eastern Sandstone and the Keweenaw Series on Keweenaw Point, Lake Superior, by R. D. Irviug and T. C. Chamberlin. 1885. 8°. 124 pp. 17 pi. 

Price 15 cents.

24. List of Marine Mollusca, comprising the Quaternary Fossils and recent forms from American 

Localities between Cape Hatteras and Cape Roque, including the Bermudas, by William Healy Ball. 

1885. 8°. 336pp. Price 25 cents.

25. The Present Technical Condition of the Steel Industry of the United States, by Phineas Barnes. 

1885. 8°. 85 pp. Price 10 cents.

26. Copper Smelting, by Henry M. Howe. 1885. 8°. 107 pp. Price 10 cents.

27. Report of work done in the Division of Chemistry and Physics, mainly during the fiscal year

1884-'85. 1886. 8°. 80pp. Price 10 cents.

28. The Gabbros and Associated Hornblende Rocks occurring in the neighborhood of Baltimore, 

Md., by George Huntington Williams. 1886. 8°. 78 pp. 4 pi. Price 10 cents.

29. On the Fresh-water Invertebrates of the North American Jurassic, by Charles A. White. 1886. 

8°. 41 pp. 4 pi. Price 5 cents.

30. Second Contribution to the Studies on the Cambrian Faunaa of North America, by Charles Doolittle Walcott. 1886. 8°. 369pp. 33 pi. Price 25 cents.

31. Systematic Review of our Present Knowledge of Fossil Insects, including Myriapods and Arachnids, by Samuel Hubbard Scudder. 1886. 8°. 128 pp. Price 15 cents.

32. Lists and Analyses of the Mineral Springs of the United States; a Preliminary Study, by Albert 

C. Peale. 1886. 8°. 235 pp. Price 20 cents.

33. Notes on the Geology of Northern California, by J. S. Diller. 1886. 8°. 23 pp. Price 5 cents.

34. On the relation of the Laramie Mollusoan Fauna to that of the succeeding Fresh-water Eocene 

and other groups, by Charles A. White. 1886. 8°. 54 pp. 5 pi. Price 10 cents.

35. Physical Properties of the Iron-Carburets, by Carl Barus and Vincent Strouhal. 1886. 8°. 62 

pp. Price 10 cents.

36. Subsidence of Fine Solid Particles in Liquids, by Carl Barus. 1886. 8°. 58 pp. Price 10 cents.

37. Types of the Laramie Flora, by Lester F. Ward. 1887. 8°. 354 pp. 57 pi. Price 25 cents.

38. Peritlotite of Elliott County, Kentucky, by J. S. Diller. 1887. 8°. 31 pp. 1 pi. Price 5 cents.

39. The Upper Beaches and Deltas of the Glacial Lake Agassiz, by Warren Upham. 1887. 8°. 84 

pp. 1 pi. Price 10 cents.

40. Changes in River Courses in Washington Territory due to Glaciation, by Bailey Willis. 1887. 

8°. 10 pp. 4 pi. Price 5 cents.

41. On the' Fossil Faunas of the Upper Devonian the Geneseo Section, New York, by Henry S. 

Williams. 1887. 8°. 121 pp. 4 pi. Price 15 cents.

42. Report of work done in the Division of Chemistry and Physics, mainly during the fiscal year

1885-'86. F. W. Clarke, chief chemist. 1887. 8°. 152 pp. 1 pi. Price 15 cents.

43. Tertiary and Cretaceous Strata of the Tuscaloosa, Touibigbee, and Alabama Ri.vers, by Eugene 

A. Smith and Lawrence C. Johnson. 1887. 8°. 189 pp. 21 pi. Price 15 cents.

44. Bibliography of North American Geology for 1886, by Nelson H. Dartou. 1887. 8°. 35 pp. 

Price 5 ceuta.
IV - ADVERTISEMENT.

45. Tho Present Condition of Knowledge of tlie Geology of Texas, by Eobert T. Hill. 1887. 8°. 94 

pp. Price 10 cents.

46. Nature and Origin of Deposits of Phosphate of Lime, by R. A. F. Penroae, jr., with an Introduction by N. S. Shaler. 1888. 8°. 143pp. Price 15 cents

47. Analyses of Waters of the Yellowstone National'Park, with an Account of the Methods of 

Analysis employed, by Frank Austin Goooh and James Edward Whitfleld. 1888. 8°. 84 pp. Price 

10 cents.

48. On the Form and Position of the Sea Level, by Eobert Simpson "Woodward. 1888. 8°. 88 pp. 

Price 10 cents.

49. Latitudes and Longitudes of Certain Points in Missouri, Kansas, and New Mexico, by Robert 

Simpson Woodward. 1889. 8°. 133 pp. Price 15 cents.

50. Formulas and Tables to facilitate the Construction and Use of Maps, by Robert Simpson Woodward. 1889. 8°. 124 pp. Price 15 cents.

51. On Invertebrate Fossils from the Pacific Coast, by Charles Abiathar White. 1889. 8°. 102 pp. 

14 pi. Price 15 cents.

52. Subaorial Decay of Rocks and Origin of the Red Color of Certain Formations, by Israel Cook 

Russell. 1889. 8°. 05 pp. 5 pi. Price 10 cents.

53. The Geology of Nautucket, by Nathaniel Southgate Shaler. 1889. 8°. 55 pp. 10 pi. Price 10 

cents.

54. On the Thermo-Electric Measurement of High Temperatures, by Carl Barus. 1889. 8°. 313pp. 

incl. 1 pi. 11 pi. Price 25 cents.

55. Report of work done in the Division of Chemistry and Physics, mainly during the fiscal year 

1886-'87. Frank Wiggles worth Clarke, chief chemist. 1889. 8°. 96pp. Price 10 cents.

56. Fossil Wood and Lignite of the Potomac Formation, by Frank Hall Knowlton. 1889. 8°. 72 pp. 

7 pi. Price 10 cents.

57. A Geological Reconnaissance in Southwestern Kansas, by Robert Hay. 1890. 8°. 49 pp. 2 pi. 

Price 5 cents.

58. The Glacial Boundary in Western Pennsylvania, Ohio, Kentucky, Indiana, and Illinois, by George 

Frederick Wright, with an introduction by Thomas Chrowder Chamberlin. 1890. 8°. 112 pp. iucl. 

1 pi. 8 pi. Price 15 cents.

59. The Gabbros and Associated Rocks in Delaware, by Frederick D. Chester. 1890. 8°. 45 pp. 

1 pi. Price 10 cents.

CO. Report of work done in the Division of Clioraistry and Physics, mainly'during the fiscal year 

1887-'88. F. W. Clarko, chief chemist. 1890. 8°. 174 pp. Price 15 cents.

61. Contributions to the Mineralogy of the Pacific Coast, by William Haiiow Melville and Waldemar 

Lindgren. 1890. 8°. 40 pp. 3 pi. Price 5 cents.

62. The Greenstone Schist Areas of the Meuomiuee and Marquette Regions of Michigan; a contri 

butiou to the subject of dynamic metamorphism in eruptive rocks, by George Hunting-ton Williams; 

with an introduction by Roland Duor Irving. 1890. 8°. 241pp. 10 pi. Price 30 cents.

63. A Bibliography of Paleozoic Crustacea from 1C98 to 1889, including a list of North American 

species and a systematic arrangement of geuora, by Anthony W". Vogdes. 1890. 8°. 177 pp. Price 

15 cents.

64. A report of work done in the Division of Chemistry and Physics, mainly during the fiscal year 

1888-'89. F. AY". Clarke, chief chemist. 1890. 8°. 60 pp. Price 10 cents.

65. Stratigraphy of the Bituminous Coal Field of Pennsylvania, Ohio, and West Virginia, by Israel 

C. White. 1891. 8°. 212 pp. 11 pi. Price 20 cents.

66. On a Group of Volcanic Rocks from the Tewaii Mountains, New Mexico, and on the occurrence 

of Primary Quartz in certain Basalts, by Joseph Paxson Iddiugs. 1890. 8°. 34 pp. Price 5 cents.

67. The Relations of the Traps of the Newark System in the New Jersey Region, by Nelson Horatio 

Dartou. 1890. 8°. 82 pp. Price 10 cents.

68. Earthquakes in California in 1889, by James Edward Keeler. 1890. 8°. 25 pp. Price 5 cents.

69. A Classed and Annotated Bibliograpliy of Fossil Insects, by Samuel Hnbbard Scudder. 1890. 

8°. 1P1 pp. Price 15 cents.

70. Report on Astronomical Work of 1889 and 1890, by Robert Simpson Woodward. 1890. 8°. 79pp. 

Price 10 cents.

71. Index to the Known Fossil Insects of the Worhl, including Myriapods and Arachnids, by Samuel 

Hubbard Scudder. 1891. 8°. 744pp. Price 50 cents.

72. Altitudes between Lake Superior and the R0cky Mountains, by Warren Upham. 1891. 8°. 

229 pp. Price 20 cents. : 73. The Viscosity of Solids, by Carl Barns. 1891. 8°. xii, 139 pp. C pi. Price 15 cents.

74. The Minerals of North Carolina, by Frederick Augustus Genth. 1891. 8°. 119 pp. Price 15 

cents.

75. Record of North American Geology for 1887 to 1889, inclusive, by Nelson Horatio Darton. 1891. 

8°. 173 pp. Price 15 cents.

76. A Dictionary of Altitudes in the United States (second edition), compiled by Henry Gannett, 

chief topographer. 1891. 8°. 393 pp. Price 25 cents.

77. The Texau Permian and its Mesozoic Types of Fossils, by Charles A. White. 1891. 8°. 51 pp. 

4 pi. Price 10 cents.
ADVERTISEMENT. V

78. A report of work done in the Division of Chemistry and Physics, mainly during the fiscal, year 

1889-'90. F'. W. Clarke, cnief chemist. 1891. 8°. 131pp. Price 15 cents.

79. A Late Volcanic Eruption in Northern California and its Peculiar Lava, by J. S. Diller. 1891. 8°. 

33 pp. 17 pi. Price 10 cents.

80. Correlation papers Devonian and Carboniferous, by Henry Shaler.Williams. 1891. 8°. 279 pp. 

Price 20 cents.

81. Correlation papers Cambrian, by Charles Doolittle Walcott. 1891. 8°. 447 pp. 3 pi. Price 

25 cents.

82. Correlation papers Cretaceous, by Charles A. White. 1891. 8°. 273 pp. 3 pi. Price 20 cents.

83. Correlation papers Eocene, by William .Bullock Clark. 1891. 8°. 173pp. 2 pi. Price 15 cents.

84. Correlation papers Neocene, by W. H. Dall and G. D. Harris. 1892. 8°. 349 pp. 3 pi. Price 

25 cents.

85. Correlation papers The Newark System, by Israel Cook Russell. 1892. 8°. 344 pp. 13 pL 

Price 25 cents.

86. Correlation papers Archean and Algonkian, by C. R. Van -Hiso. 1892. 8°. 549 pp. 12 pi. 

Price 25 cents.

90. A report of work done in the Division of Chemistry and Physics, mainly during tho fiscal year 

1890-'91. F. W. Clarke, chief chemist. 1892. 8°. 77 pp. Price 10 cents.

91. Record of North American Geology for 1890, by Nelson Horatio Dartou. 1891. 8°. 88 pp. Price

10 cents.

92. The Compressibility of Liquids, by Carl Barus. 1892. 8°. 06pp. 29 pi. Price 10 cents.

93. Some insects of special interest from Florissant, Colorado, aud other points in the Tertiaries of 

Colorado and Utah, by Samuel Hubbard Scudder. 1892. 8°. 35 pp. 3 pi. Price 5 cents.

94. The Mechanism of Solid Viscosity, by Carl Barns. 1892. 8°. 138 pp. Priee 15 cents.

95. Earthquakes in California in 1890 and 1891, by Edward Singleton Holden. 1892. 8°. 31 pp. 

Price 5 cents.

96. The Volume Thermodynamics of Liquids, by Carl Barns. 1892. 8°. 100 pp. Price 10 cents.

97. The Mesozoic Echiiiodennata of the United States, by W. B. Clark. 1893. 8°. 207 pp. 50 pi. 

Price 20 cents.

98. Flora of the Outlying Carboniferous Basins of Southwestern Mis8oi,ri,by David White. 1893. 8°. 

139 pp. 5 pi. Price 15 cents.

99. Record of North American Geology for 1891, by Nelson Horatio Darton. 1892. 8°. 73 pp. 

Price 15 cents.

100. Bibliography and Index of the publications of the U. S. Geological Survey, 1879-1892, by Philip 

Groveling Warman. 8°. 495'pp. Price 25 cents.

101. Insect Fauna of the Rhode Island Coal Field, by Samuel Hubbard Scudder. 1893. 8°. 27 pp. 

2 pi. Price 5 cents.

104. Glaciation of the Tellowstone Valley north of the Park, by W. H. Weed. 1893. 8°. 41 pp. 

4 pi. Price 5 cents.

105. The Laramie and the overlying Livingston Formation in Montana, by Walter Harvoy Weed, 

with Report on Flora, by Frank Hall Knowlton. .1.893. 8°. 68 pp. 6 pi. Price 10 cents.

106. The Colorado Formation and its Invertebrate Fauna, by T.JW. Stanton. 1893. 8°. 288 pp. 

45 pi. Price 20 cents.

108. A Geological Reconnoissanoe in Central Washington, by Israel Cook Russell. 1893. 8°. 108pp. 

12 pi. Price 15 cents.

In press:

102. A Catalogue and Bibliography of North American Mesozoio Invertebrata, by C. B. Boylo.

103. High Temperature Work in Igneous Fusion and Ebullition, chiefly in relation to pressure, by 

Carl Barns. 

107. Tho Trap Dikes of Lake Champlain Valley and the Eastern Adirondacks, by J. F. Kemp.

109. The Eruptive and Sedimentary Rocks on Pigeon Point, Minnesota, and their contact phenomena, by W. S. Bayley.

110. The Paleozoic Section in the vicinity of Three Forks, Montana, by A. C. Peale. 

In preparation:

 The Moraines of the Missouri Coteaii, and their attendant deposits, by James Edward Todd.

 On the Structure of the Ridge between the Taconic and the Green Mountain Ranges in Vermont; and On^the Structure of Monument Mountain in Great Barrington, Mass., by T. Nelson Dale.

 A Bibliography of Paleobotany, by David White.

STATISTICAL PAPERS.

Mineral Resources of the United States, 1882, by Albert Williams, jr. 1883. 8°. xvii, 813 pp. Price 

50 cents.

Mineral Resources of the United States, 1883 and 1884, by Albert Williams, jr. ]885. 8°. xiv, 1016 

pp. Price 60 cents.

Mineral Resources of tho United States, 1885. Division of Mining Statistics and Technology. 1886. 

8°. vii, 576 pp. Price 40 cents.
VI ADVERTISEMENT

Mineral Resources ot the United States, 1886, by David T. Day. 1887. 8°. viii,813pp. PriceSOcents.

Mineral Resources of the United States. 1887, by David T. Day. 1888. 8°. vii, 832pp. Price 50 cents.

Mineral Resources of the United States, 1888, by David T. Day. 1890. 8°. vii, 952 pp. Price 50 cents.

Mineral Resources of the United States, 1889 and 1890, by Pavid T. Day. 1892. 8°. viii, 671 pp. 

Price 50 cents. ' j

Mineral Resources of the United States, 1891, by David T. Day. 1893. 8°. vii, 630pp. Price 50 cents. 

Jn preparation:

Mineral Resources of the United States, 1892.

The money received from the sale of,these publications is deposited in the Treasury, and the Seer* 

tary of the Treasury declines to receive bank checks, drafts, or postage stamps; all remittances, therefore, must be by POSTAL, NOTE or MONEY ORDER, made payable to the Chief Clerk of the U. S. Geological 

Survey, or in CURRENCY, for the exact amount. Correspondence relating to the publications of the 

Survey should be addressed

To THE DIRECTOR OF THE

UNITED STATES GEOLOGICAL SURVEY,

WASHINGTON, D. C 

WASHINGTON, D. C., Auyust, 1893.
DEPARTMENT OP THE INTERIOR

BULLETIN

OF THE

UNITED STATES

GEOLOGICAL SURVEY

No. 1O6

WASHINGTON

GOVERNMENT PRINTING OFFICE 

1 8 9 3

UNITED STATES GEOLOGICAL SURVEY

J. W. I'OWELL, DIRECTOR

THE

COLOEADO FOEMATION

AND ITS

INVERTEBRATE FAUNA

TIMOTHY W. STANTON

WASHINGTON

GOVERNMENT PRINTING OFFICE 

1893

CONTENTS.

Page.

Letter of transmittal ....................................................... 9

Preface..................................................................... 11

Introduction................................................................ 13

History and definition of the Colorado formation........................ 13

Geologic description........................................................ 20

The eastern border...................................................... 20

The Upper Missouri region...................... ...... .................. 23

Colorado and New Mexico............................................... 25

Utah ...............................................:.............'...... 34

The relations of the Colorado fauna to other Cretaceous faunas.............. 47

Description of species ...................................................... 52

Echinoderinata .....................J................................... 52

Vermes................................................................. 53

Mollusca ............................................................... 54

Pelecypoda ..................................t....................... 54

Gastropoda......................................................... 127

Cephalopoda........................................................ 163

Arthropoda............................................................. 189

Crustacea........................................................... 189

Plates...................................................................... 191

Index....................................................................... 283

5

ILLUSTRATIONS.

Pago.

PLATE. I. Serpulidae and Ostreidaj.......................................... 194

II. Ostreidai ........................................................ 196

III. Ostreida) ........................................................ 198

IV. Ostreida) ..»....».... tl .. 14 ...................................... 200

V. Ostreidai ..........sii ...... s ..............................i..... 202

VI. Ostreidte ..» 4 . 4i4 ................................................ 204

VII. Ostreid® ........................................................ 206

VIII. Ostreida) and Auomiidae ......................................... 208

I.. Spondylidte, LiuiLdaj, PectinUUe, AviouluUe ...................... 210

X. Avioulidie....................................................... 212

XI. Aviculida . ...1.................................................. 214

XII. Aviculid»....................................................... 216

XIII. Avictilidte....................................................... 218

XIV. Aviculidse....................................................... 220

XV. Avioulidw........................................................ 222

XVI. Avioulidw....................................................... 224

XVII. AvioulidBB....................................................... 226

XVIII. Avioulidse....................................................... 228

XIX. Mytilidro, Pinnidre, ArcidiB ...................................... 230

XX. Pinnidm, Arcidai................................................. 232

XXI. Arcidai, Nuculidso, Solemyida), Crassatellida) ..................... 234*

XXII. Unionidi&, Lncinidoe, Cardiida?, Cyrenidse ......................... 236

XXIII. Cyrenidaj; Cyprinida> ............................................ 238

XXIV. Veneridsj........................................................ 240

XXV. Donacidao, Tellinidte, Solenidas.................................... 242

XXVI. Pholadomyida), Auafcinidse ....................................... 244

XXVII. Mactridaj, Myidte, Pholadid® ..................................... 246

XXVIII. Neritidai.TiHTitellidai............................................ 248

XXIX. Tnrritellidae, Xenophoridas, Naticidse ............................. 250

XXX. Naticida), Pyraioidellidse, Rissoidse............................... 252

XXXI, Aporrliaida), Strombidoe, TritonidsejFusidaj....................... 254

XXXII. Fnsidao.......................................................... 256

XXXIII. Cancellariidse, Volutidce.......................................... 258

XXXIV. Volntido), Plenrotomidas, Actaonida), Bnllidte...................... 260

XXXV. Nautiloidea, Ammonoidea ........................................ 262

XXXVI. Ammonoidea..................................................... 264

XXXVII. Ammonoidea..................................................... 266

XXXVIII. Ammonoidea..................................................... 268

XXXIX. Ammonoidea..................................................... 270

XL. Ammonoidea..................................................... 272

XLI. Ammonoidea..................................................... 274

XLII. Ammonoidea..................................................... 276

XL1II. Ammonoidea...................................................... 278

XLIV. Ammonoidea..................................................... 280

XLV. Ammonoidea..................................................... 282

7

LETTER OF TRANSMITTAl.

DEPARTMENT OF THE INTERIOR,

UNITED STATES GEOLOGICAL SURVEY, 

DIVISION OF MESOZOIC INVERTEBRATES,

Washington, 1). 0,, July 50, 1892.

SIR: I have the honor to transmit herewith a memoir by Mr. T. W. 

Stanton on the Colorado Formation and its Invertebrate Fauna, prepared for publication as a bulletin. The work was begun by him at 

my suggestion, and I have, as chief of the division with which he is 

connected, been constantly cognizant of its progress. 

Very respectfully,

C. A. WHITE, 

Geologist in Charge. 

Hon. J. W. POWELL,

Director of the U. 8. Geological Survey.

PREFACE.

The following review of one of the Upper Cretaceous fannas as 

developed in- the interior region of the United States has grown out 

of the study of a collection of fossils found by me in Huerfauo park 

and adjacent localities in southern Colorado. This collection, the 

greater part of which was obtained during the summer of 1890, proved 

to be especially interesting because it afforded data for the closer correlation of certain Cretaceous strata in Utah with those east of the 

mountains, besides adding a considerable number of new species to the 

fauna of the Colorado formation. Dr. C. A. White, under whose direction the field work was done, generously assigned these fossils to me 

for study with a view to publishing the results, and I am greatly indebted to his sympathetic aid in every phase of the work.

The stratigraphic position of the Huerfano park fossils had been 

fully established in the field to be beneath the Niobrara division of the 

Colorado formation. In making the preliminary comparisons of species it soon became evident that the fauna of this horizon was much 

richer than had been supposed. Only about twenty-five or thirty 

species of invertebrates had been definitely assigned to the strata 

that are now included in the Colorado" formation. Many had been 

described simply as Cretaceous without assignment to more definite 

horizons and a considerable number of other species had been erroneously referred to the overlying Montana formation. It therefore 

became necessary to study AS far as practicable the vertical range and 

the faunal associates of these doubtful species, especially those reported from, Utah and New Mexico, making use of the collections of the 

U. S. National Museum and of the Geological Survey, as well as the 

published reports and my own observations in the field. This investigation added a large number of species to the fauna of the Colorado 

formation and showed the desirability of bringing together in one publication the scattered descriptions and illustrations of all the species 

that can now be assigned to the fauna. While making.this compilation the nomenclature and descriptions of the species have been revised in all cases in which better collections or other additional facts 

seemed to make it necessary. Thirty-nine species are described that 

are believed to be new to science.

The purely paleoutologic portion of the work is supplemented by a

11
12 PREFACE.

geologic introduction in which the Colorado formation is defined, many 

local sections are described, and faunal lists are given that show the 

vertical range and areal distribution of the most of the species. Incidentally, some new evidence concerning the position of the Bear Eiver 

formation is given, and large areas of Cretaceous strata in Utah are 

correlated with tlie formations east of the Eocky mountains more accurately than lias heretofore been possible.

In addition to the aid received from Dr. C. A. White and the free 

use of the collections under his curatorship in the U. S. National 

Museum, I am under many obligations to Dr. W. H. Ball and to Mr. 

Charles T. Simpson, of the National Museum., for assistance in comparing fossils with recent species, and for valued opinions concerning tbe 

generic relations of doubtful forms5 also to Prof. Alplieus Hyatt, who 

has examined several of the species of Ammonitince at my request, and 

has given me the benefit of his authoritative opinion as to their relationships.

T. W. S.
THE COLORADO FORMATION AND ITS INVERTEBRATE FAUNA.

ByT. W. STANTON.

INTRODUCTION. 

HISTORY AND DEFINITION OF THE COLOEADO FORMATION.

For many years the well-known upper Missouri section lias served as 

the basis for all studies in the Cretaceous formations of the great interior region of the United States. As first published in 1856, by Hall 

and Meek, 1 and with a few slight modifications, by Meek and Hayden,2 

it embodied the notes on the Cretaceous strata made by the two authors 

last named during the earliest of their geological reconnoissances in 

the upper Missouri river region. It has since been modified and enlarged from time to time by the same authors and by others, and made 

to include, more or less successfully, all the Upper Cretaceous strata 

in the region from Kansas to Arizona and from southern New Mexico 

far northward into British America.

In its original form this upper Missouri section was divided into five 

parts, which were simply designated by numbers, beginning at the base. 

The total thickness of the entire Cretaceous series of that region was 

at first estimated at not more than 650 feet. In 1861 Messrs. Meek and 

Hayden3 published a paper in which names were given to the five divisions, with the addition of lists of characteristic fossils and references to 

typical localities. It should be remembered that this is not a continuous section at any one locality, but it is generalized from all the outcrops seen over a very large area. The thickness assigned to each 

group is an estimate of its maximum development. The section, as 

republishe'd in 1876 by Meek,4 who made no changes excepting in the 

nomenclature of a few of the fossils, is as follows:

1 Mom. An^. Acad. Arts, and Sci.. 2il ser., vol. v, p. 405.

2 Proc. Acad. Nat. Sci. Phila., vol. vni, p. 63.

aproc. Acad. Nat. Sci. Pliila., 1861, p. 419.

* TJ. S. Gool. Sur. of the Territories, vol. ix, pp. xxiv and xxv.

13
14 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA, [unu.100. 

General section of the Cretaceous roclcs of Nebraska.

u

_

O O

Divisions and subdivisions.

Gray, ferruginous, and yelloAvish sandstone and arenaceous clays, containing Belemnitella bulbosa, Nautilus 

Dekayi, Placenticeras placenta, P. 

lenticularis, Scaphites Conradi, S. 

Nicolleti, Baculites grauclis, Pyropsis 

Bairdi, Piestochilus Culbertsoni, Pyrifusus Newberryi, Anclmra Americana, Pseudobuccinum Nebrascensis, 

Mactra Warrenana, Cardium subquadratum, and a great number of 

othermollnscanfossiis, together with 

bones of Mosasaurus luissouriensis, 

etc.

Dark-gray and bluisli plastic clays, 

containing, near the upper part, 

Nautilus Dekayi, Placenticeras placenta, Baculites ovatus, B. coi'npressus, Scaphites uodosus, Dentalium 

gracile, Crassatella. Evansi, Cuculia'.aNcbrasceusis, Inoceramus Sagensis, I. Ncbrasconsis, I- Vaiuixemi, 

bones of Mosasaurus missourieiisis, 

etc.

Middle zone nearly barren of fossils.

Lower fossiliferous zone, containing 

Ammonites coinplexus, Baculites 

ovatus, B. compressuSj Heteroceras 

Mortoui, H. tortum, H. umbilicatuin, 

H. cocbleatum, Ptychoceras Mortoui, 

Odontobasis vinculum, Anisomyon 

borealis, A'uiauropsis paludiuiforiuis, 

luoceramns snblaivis, I. teuuilineatns, bones of Mosasaurus missourionsis, etc.

Dark bed of very fine unctuous clay, 

containing much ca>rbonaceous matter, with veins and seams of gypsum, 

masses of sulphuret of iron, and 

numerous small scales of iishes. 

Local; filling depressions in the bed 

below.

Localities.

Fox Hills, n e a r 

More an river; 

nea? Long hike, 

above Fort 

Pierre; along 

the base of the 

Big Horn monntainH, and on 

North and South 

Platte rivers.

Sage creek, Cheyenne river, and 

on White river 

above the Mn,uvaiscs Torres.

Fort Pierre and 

out to Bad 

Lands; also 

down the Missouri on the high 

country to Great 

Bend.

Great Bend of the 

Missouri below 

Fort PioiTO.

Near Bijou Hill, on 

the Missouri.
STANTON.] . MEEK AND HAYDEN'S SECTION. 15 

General section of the Cretaceous roclcs of Nebraska Continued.

Divisions and subdivisions.

CO

45 'rH

02

rH

0

0

Niobrara Division, Formation No.3.

|H

Oj5

d a

5.1 S *» 

45 C3

 PQ a

 *=> o

O HH

PH

rH

6

Group. Formation 1;a

o

 3

Lead-gray calcareous marl, weathering to a yellowish or whitish chalky

appearance above. Containinglarge 

scales and other remains of fishes, 

and many specimens of Ostrea congesta attached to fragments of Inoceramns ; also several species of Textularia. Passing down into light, 

yellowish, and whitish limestone, 

containing great numbers of Inoceranius probleinaticus, I. pseudomytiloidos, I. avionloides, and Osfcrea

congesta, tisu-scales, etc.

Dark - gray laminated clays, sometimes alternating near the upper

part with seams and layers of soft

gray and light-colored limestone.

Inpcorauius probleinaticus, I. tenuirostratus, I. latus ? I. fragilis, Ostrea

cougesta, Veuiella Mortoni, Pholadoinya papyracoa, Ammonites Mullanauus, Priouocyclus Woolgari,

Mortoniccras Shoshonense, Scaphites

Warronanus, S. larvteformis, S.

veutricosus, S. vormiformis, Nautilus

elcgaus, etc.

Yellowish, reddish, and occasionally 

white sandstone, with atplaces alternations of various colored clays and 

beds and seams of impure lignite; 

also silicified wood, and great numbers of leaves of the higher types of 

dicotyledonous trees, with casts of 

Pharolla ? Dakotensis, Trigouarca 

Siouxensis, Cyreua arenarca, Margaritana Nebrascensis, etc.

«-

Localities.

Bluffs along the 

Missouri below 

the Great Bend, 

to the vicinity 

of Big Sioux 

river; also below there on the 

tops of the hills.

Extensively developed near Fort

Bentou on the

Upper Missouri ;

also along the

latter from 10

miles above

James river to

Big Sioux river;

and along the

eastern slope of

the Kockymountains, as Avell as

at the Black

Hills.

Hills back of the

town of Dakota;

also extensively 

developed in the 

surrounding 

country in Dakota county below the mouth 

of Big Si-oux 

river; a n d 

thence extending southward 

into northeastern Kansas and

beyond.

 *? <D .§ !

1»r3

.0

05 «2

o

O

GO

feet. 400 

d

«s

d5

 rH

a 

2

H,

'Sb 

o

"o

05

be

en

m

o .

rti £

«-r-C

C rH

4jP

rt ^

O

45 d

ft'3

K> 5

13 |

rt d

^ O

1«

O

>5

(-

O

8

6;

0 

0

CO

_3 "3

3

To complete the Upper Cretaceous section of this region there must 

be added to it at the top the great coal bearing- Laramie series of fresh 

and brackish water beds, which were regarded as Tertiary at the time 

of the earlier explorations, but are now generally assigned to the Cretaceous; and in western Wyoming the Bear Eiver formation must be 

interpolated. It is also a brackish-water formation, and Avas formerly
16 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL. 106.

believed to be a part of the Laramie. 1 It lias recently been shown^to 

occupy a much lower horizon, probably about that of Dakota.

As explorations were extended throughout the West it was found 

that, while the divisions of the above sections can be recognized over a 

large area, there are regions in which they can be applied only with 

the greatest difficulty, if at all. They had been separated in the first 

place mainly on account of lithologie differences, though the lines thus 

drawn happened to coincide with decided faunal breaks in one or perhaps two instances. Naturally, the strati graphic units thus denned 

are more or less restricted in their geographic distribution, and are 

sometimes represented in other regions by deposits of an entirely different character. For example, in large areas west of the Continental 

Divide the limestone and marls of the Mobrara are not found, they 

being variously represented at different localities by shales and sandstones. Under such circumstances it is very difficult to discriminate 

between the dark shales of the Fort Bentou and those of the Fort 

Pierre, unless characteristic fossils are found. This difficulty was 

encountered by the geologists of the United States Geological Exploration of the Fortieth parallel, and as a solution of it Mr. Clarence 

KiDg, the chief of that survey, proposed the new term Colorado Group 

u for the great clay group" of the Cretaceous, making'it include the 

equivalents of the Fort Benton, Mobrara, and Fort Pierre groups of 

Meek and Hayden.

The name " Colorado Group" was first published in 1875 on one of 

the atlas sheets of the Fortieth Parallel Survey, and it was more fully 

defined by Messrs. King, Hague, and Emmons in vols. I and n of the 

final reports of the same survey. The name has since been used with 

the same meaning by several other geologists.2

But the lithologic classification of the Cretaceous formations adopted 

by the Fortieth Parallel Survey is often as difficult to apply as the older 

one which it was intended to replace, even in the region for which it 

was first proposed; for on approaching the western shore line of the 

Cretaceous sea along the eastern base of the Wasatch mountains, the 

Colorado formation ceases to be a " great clay group " bounded by sandstones above and below. On the contrary, there are several alternations of similar heavy beds of sandstone with dark shales throughout 

the entire series, and no good lithologic or structural reasons can be 

given for separating them into groups. The section at Coalville,Utah, 

to be given further on, is a good example of this. Kecent paleontologic 

studies have shown that on the maps of the Fortieth Parallel Survey the 

upper limit of the Colorado formation at that place is really drawn not 

higher than the top of the Mobrara. It may be added that in that

»Vide White, C. A.: On the Boar River Formation. Am. Jour. Sci., vol. XLIII, 1892, pp.91-97; and 

Stanton, T. W.: Stratigraphic Position of the Bear River Formation. Ibid., pp. 98-115.'

*For the nomenclature and grouping adopted by various authors who have written on the Cretaceous 

of this region see White. C. A.: A Review of the Cretaceous Formations of North America, Bull. 

No. 82, IT. S. Geol. Sur., from which most of the historical statements here given were obtained.
STASTOK.] FORMATIONS CHARACTERIZED BY THEIR FAUNA. 17

region the paleontologic lines are not so sharply drawn as they are east 

of the Front range, though the fauna as a 'whole in the lower part of the 

series corresponds with that in the lower portion of the' Meek and 

Hayden section, and is very different from that of the tipper.

In the rapid reconnoissance of such large areas as were covered by 

the earlier surveys in the West there was little time for detailed paleontologic work, and the geologists were therefore often obliged to 

classify and describe the formations by their most obvious lithologic 

and structural characteristics. But such classification can be regarded 

only as tentative, and Avheu, as in the case now under consideration, 

the lower portion of a " group" or formation is found to contain a faun a 

that is entirely distinct from that of the upper portion, while the latter 

is very closely related to the fauna of the overlying formation, it is

evident that the plane of separation has not been drawn on the right

horizon. A decided change in marine faunas occurring at approximately the same horizon, over a large area is evidence of either a considerable time interval or of some great change in external physical 

conditions, and in either case it should haveA^eight in geological classification, even though the character of the sediments may be so nearly 

the same both above and below the faunal break that no reason other 

than the paleontologic one can be seen for their division. Such a difference between adjacent marine fossil faunas certainly represents a 

more important event than the change from a sandstone to a shale or 

from a shale to a limestone. These general facts are universally 

admitted and numerous examples could be cited in which the dividing 

line between formations as widely separated in age as the Cambrian 

and the Carboniferous or the Jurassic and the Upper Cretaceous could 

not be determined until the fossils were studied. But when the faunas 

both belong to the same geologic period they are more closely related 

and the importance of such a faunal change is likely to be underestimated by the field geologist.

Meek and Hayden early recognized the fact that the most marked 

faunal break in their Cretaceous section is at the top of the Mobrara 

division, and for that reason the line between the '< Lower Series " and 

the " Upper Series" was placed there. In Prof. Meek's last published 

work1 he says:

In passing from the Niobrara group, however, into the succeeding rocks above, in 

which great numbers of fossils occur, not <a single species, so far as known to the 

writer, has yet been found identical with any form yet known from either of the 

thfee divisions below. In addition to this, the upper surface of the Niobrara beds is, 

at several places on the Missouri river, seou to have been eroded into irregularities 

or depressions, previous to the deposition of the succeeding Fort Pierre group, thus 

giving additional evidence that some kind of a physical change (perhaps slight) 

occurs between the deposition of the latest portion of the Niobrara division and the 

first of the Fort Pierre beds.

It is now known that a few species do pass from the lower series to

1 U. S. Geol. Sur. Terr., vol. ix, p. xxxn.

Bull. 106 2
18 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [HULL. 103.

the upper, but this is exceptional. The great majority of the species 

and all of the abundant ones are distinct, consequently Prof. Meek's 

argument for making the primary division at the top of the Mobrara 

is not impaired.

In 1878, when describing the Cretaceous formations of northwestern 

Colorado, Dr. C. A. White 1 used the nomenclature of King, dividing 

the section into the Dakota, Colorado, and Fox Hills groups, but for 

reasons similar to those just enumerated he applied the term Colorado 

group only to the equivalents of the Fort Benton and the Niobrara, 

while the Fort Pierre was embodied in the Fox Hills group. These two 

groups as thus defined are equivalent respectively to the marine portions of the Lower Series and the Upper Series of Meek and Hay den, 

and are characterized by distinct marine faunas, though there may also 

be in either of them local intercalations of fresh-water or brackishwater deposits.

This method of grouping the formations was adopted by some of the 

other geologists of the Survey of the Territories, and it was used on 

the maps of the Atlas of Colorado.

Mr. George H. Eldridge 2 has recently published an excellent general 

review and discussion of the classification and nomenclature of the 

Western Cretaceous, in which he adopted the divisions as defined by 

Dr. White,-but he proposed the new name Montana group for the combined Fort Pierre and Fox Hills. In this manner the confusion caused 

by using the name Fox Hills in two different senses is avoided, and the 

original names of the minor subdivisions may still be used in local 

sections where it is desirable.

After describing each member of the Upper Cretaceous section, especially as developed along the eastern base of the Front range in Colorado, Mr, Eldridge sums up the evidence thus:

From the foregoing details, the following relations of the several formations 

to each other may be clearly and legitimately deduced: First, the component strata 

of the Fort Benton and Niobrara frequently, and the life generally shade into each 

other; second, this is again evenmore forcibly paralleled in the sedimentation and life 

of the Fort Pierre and Fox Hills; third and on the contrary between the Niobrara 

and Fort Pierre, or, which is the same thing, between the Colorado and Montana 

groups (as was suggested they should be designated early in the paper), there is a 

differentiation of both sediments and life, greatly in excess of any similarities in 

these respects that may be noticed from time to time in any particular locality.

Some of the detailed evidence in?support of these views will be given 

in subsequent paragraphs.

Mr. Eldridge has also described3 a local nonconformity at the top of 

the Colorado formation at Golden, Colo.

In the present paper the term Colorado formation is accepted in its 

restricted sense as defined by White and Eldridge. The species de1 Ann. Kept. TJ. S. Geol. Sur. Terr, for 1870, pp. 1-00. 

z Am. Jouv. Sci., 3d ser., vol. xxxvitr, 1889, p. 313-321. 

» Bull. PMlos. Soc. of Washington, vol. xi, 1890, p. 264.
STANTON.] GEOGRAPHIC DISTRIBUTION. 19

scribed by Meek and others from the typical Fort Ben ton andMobrara 

of the Upper Missouri section and from their undoubted equivalents 

in the Black hills and along the Front range in Colorado have been, 

taken as the nucleus of the fauna. To these have been added others 

from the same beds and those from other regions that are associated 

with species believed to be characteristic of this horizon. Some fortunate discoveries of an unusually abundant and varied fauna in the Fort 

Ben ton of southern Colorado, and the careful comparison of collections 

from many localities, thus correlating the beds step by step, have added 

a considerable number of species to the fauna, some of them new and 

many more that have either been assigned to a higher horizon or 

described simply as Cretaceous Avithout reference to any of its divisions. 

As a necessary result of recently ascertained facts concerning the vertical distribution of some of these species, certain strata that have

usually been referred to the Montana formation in Utah and adjoining 

States are now transferred to the Colorado. This subject will be discussed somewhat in detail when the typical sections are described.

The Colorado formation has been recognized by means of its characteristic fossils in Iowa, Minnesota, the Dakotas, Nebraska, Kansas, 

Colorado, Wyoming, Montana, Utah, Arizona, and Few Mexico. It is 

also well established that equivalent strata exist in Texas and the 

adjacent regions and over large areas in British America. In Texas 

the Eagle Ford shales and the Austin limestone are evidently the 

equivalent of the Fort Benton and th°e Niobrara, respectively, but their 

fauna is in some respects quite different from that of the typical Colorado and for that reason its peculiar species have been excluded, 

though many of those here described are known to occur in both 

regions, and it is probable that more thorough collecting will add many 

to the common list.

The species described from British America have been excluded because the geologists have often found difficulty there in discriminating 

between the Colorado and Montana formations, and consequently a 

number of the described upper Cretaceous species have not been assigned to either horizon. While many species evidently belong to the 

Colorado fauna, there are many others that are doubtful and must re1 

main so until more is known of their associates and'their stratigraphic 

position.1 For similar reasons a few known species from portions of 

our area have been omitted, some of which probably belong to this 

fauna..

From southern Utah and from New Mexico a few species are included 

whose stratigraphic position is not definitely known, but they are 

usually associated at the same locality with known Colorado species.

The area to which the Colorado formation is thus arbitrarily rc1 Since the above was written Mr. J. F. Wlliteaves has published descriptions of four new species 

of Ammonites from Ilie Cretaceous rocks of Athabasca (Trans. Eoy. Soc. Canada, sec. iv, 1802, jip. 

111-119) and referred them to the horizon of the Colorado formation. They belong to genera that have 

not yet been found in. that.formation in the United. States and are suggestive of an older horizon..
20 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL. 106

stricted is sufficiently large to show great variations in the nature and 

thickness of the sediments and considerable modifications of the faunas. 

With the 150 species of fossils all from one comparatively limited horizon, now for the first time brought together, it will be much less difficult to extend the correlation of beds belonging to the same horizon in 

this country, and to make comparisons with Cretaceous faunas as developed elsewhere.

The variations above mentioned can be best shown by describing a 

few typical sections in different parts of the area. The sections and 

their fauna! lists will be given in greater detail in. some cases where 

important new correlations are made.

GEOLOGIC DESCRIPTION. 

THE EASTERN BORDER.

On the eastern border of the area in which the Colorado formation 

occurs the country is comparatively level; the Cretaceous beds are 

nearly horizontal and are frequently covered with drift, loess or other 

recent deposits, so that there are not many good exposures showing 

the character and the thickness of the different divisions. Consequently, but little detailed work has been done here and very few local 

sections have been published. It is known that in Iowa and Minnesota, east of the main Cretaceous °area, there are many detached remnants that have escaped the general erosion and are evidence of the 

eastward extension of the Cretaceous sea. Only a lew of these isolated 

localities have yielded characteristic fossils, but since they are in an 

undisturbed region and not very far distant from the typical Meek and 

Hayden section, the beds can usually be identified with reasonable certainty by their strati graphic and lithologic relations.

In the valley of Sank river, Minnesota, there are exposures of Fort 

Benton shales that have been described by Mr. J. H. Kloos. 1 He states 

that in that region the Cretaceous rests on the older crystalline rocks, 

and only the Fort Benton division seems to be represented. One section obtained from a well showed 73 feet of dark bine clay and shales 

with two thin seams of lignite. The few fossils that were found were 

submitted to Prof. F. B. Meek, and proved to be characteristic Benton 

forms. He identified Inoceranms proUematicus (=1. labiatus] and Ammonites per'carinatus (=Prionotropis woolyari) among them.

Prof. N. H. WinchelP states that similar beds extend farther south, 

along the Minnesota river and the Cottonwood, and at other localities 

there are exposures of sandstone that are referred to the Dakota, while 

at New (Jim there is an outcrop of limestone that is believed to represent the Fiobrara.

1 Kloos, J. H. C'retaceous'Basin in the Sank Valley, Am. Jour. Sci., 3(1 ser., vol. in, 1872, pp.17-26.

2 Wiucliell. :N. H. Tlio Cretaceous in Minnesota, Miun. Acad. Nat. Sci. Bull. vol. 1,1878, pp. 349-390,
STANTON.] IOWA SECTION. 21

l.n western Iowa the Cretaceous beds are somewhat "better developed 

and the exposures are more satisfactory. The following1 description of 

the general section from the base upward is condensed from Dr. White's 

account in the Geology of Iowa.1

Iowa Cretaceous section.

1. Nishnabotauy sandstone: Feet. 

Rather coarse grained, friable, more or less ferruginous sandstone, with 

occasional thin, irregular layers oi' clay. Fossils: Fragments of angiospermous leaves. Maxi main thickness................................. 100

2. Woodbury sandstones and shales:

Alternating thin beds of shale and sandstone, the former predominating. 

The shales vary in character, and at some places a lignitLc band is 

shown. Fossils: Inoccramus labiatus and casts of a few other Lamellibranchs are occasionally found, and leaves of Saiix meekii and Sassafras 

cretaceum also occur Maximum thickness............................. 150

3. Inocef anius beds:

Impure chalky limestone and niarls with Inoceramus labialus, Ostrea con- 

(jcsta, and remains of several genera of fishes. Thickness .............. 50

A detailed section measured by Mr. O. H. St. John 2 along the Big 

Sioux river above Sioux City, in which the basal sandstone is not 

represented, shows 45 feet of the Inoceramus beds and 119 feet of the 

underlying Woodbury sandstones and shales.

The original section of Meek and Hayden was described from this 

same neighborhood, and the divisions above given correspond in a 

general way to the Dakota, Fort Benton, and Mobrara groups, though 

it seems possible that a part of the Dakota is included in the Woodbury sandstones and shales. Evidently there is a gradual transition 

liom the one formation to the other at this point, and if marine fossils 

were found to the bottom of the series we should expect them to belongto the same fauna as those in the upper beds. Four species of invertebrates have been described by Meek and Hayden from the "Dakota 

group at the mouth of Big Sioux river." Future studies may prove 

that they belong to the Colorado fauna, but as I have not been able to 

identify them satisfactorily with.species that occur in the beds above 

the Dakota elsewhere, it has seemed best to omit the description of 

them. They are:

Cyrena dakotensis. Mactra siouxensis. 

Trigonarca siouxensis. Arcopagella? macrodonta.

Southwestward from this locality the Cretaceous occupies a broad" 

irregular belt through Nebraska and Kansas, lying uuconfbrmably on 

the Carboniferous, and farther south on the red beds that are usually 

referred to the Jura-Trias. The strata dip gently to the northwest, and 

in the western part of these states the Cretaceous is overlain by freshwater deposits of late Tertiary age. Since the beds are nearly horizon-

'Kept. Gool. Sur. of Icrwa, vol. i, Dos Moinca, 1870, pp. 285-294. 

*Rept. Geol. Sin-, of Iowa, vol. n, pp. 196-109.
22 COLORADO FORMATION AKD ITS INVERTEBRATE FAUNA. [BULL. 100.

tal and the Tertiary deposits are not very thick, the streams have cut 

through into the Cretaceous for some distance with in the Tertiary area, 

thus making its boundary very irregular, Only a part of it has been 

accurately mapped.

Until recently all of the Cretaceous strata of Kansas have been 

referred to the JDakota and the Colorado formations, and there is no 

doubt that these two formations do cover a large area within the state, 

but it has been shown l that a part of the Lower Cretaceous Comanche 

series, with some of its characteristic species of fossils, occurs in several 

of the southern counties, and the probable existence of the Montana 

formation in the northwestern part of the state has been reported.

Prof. B. F. Mudge, who spent several season sin collecting vertebrate 

fossils from the Niobrara division in Kansas and visited the most of 

the Cretaceous outcrops in the.state, estimated 2 the total thickness of 

the Cretaceous at 960 feet, of which 500 feet was assigned to the 

Dakota and the remainder to the Niobrara.

The fact that the beds above the Dakota contain a greater proportion of calcareous material than usual led Prof. Mudge to con chicle that 

they all belong to the Mobrara and that the Fort Benton shales are 

absent, but it is evident from the description that his Niobrara represents the whole of the Colorado formation. The data for the following 

section of the Upper Cretaceous strata of Kansas 3 are taken from the 

paper last cited:

Kansas Upper Cretaceous section.

Feet.

1. Dakota formation.

Brown and variegated sandstone of varying degrees of hardness, frequently 

with ferruginous concretions, and usually interstrafcified with-thiu beds of 

Clay shales, and Olie 01'more seams Of lignite. Fossil plants abundant; animal3 remains rare. Estimated thickness................................. 500

2. Colorado formation.

a. Interstratified shales aud thin layers of limestone containing Inoccramus 

labialus and a few other mollusks, with occasional fish remains........... 140

6. Bluish hlack or slate colored shale Avith many concretions containing 

Prionotropis ivoolgari, Scapliites, Inoccramus, etc........................... 60

c. Massive chalky limestone with Iiwceramus deformis, Ostrea conyesia, and 

occasional remains of fish and saurians.................................. 60

d. Buif and white chalk or chalky limestone with calcareous shales. Fossils: 

Uintacrinus socialis, Inocerainus laMatus, I. deformis?, Ostrea congesta, Radiolitesf, .Bactilites anceps? and great numbers of vertebrates., including birds, 

reptiles, and fishes. Thickness ......................................... 200

Estimated total thickness of the Colorado ............................... 460

1 Cragin, I\ W. The Cheyenne Sandstone and the Ncocomian Shales of Kansas. Washburn College 

Lab. of Nat. Hist. Bull., vol. n, No. 11, and Am. Geologist, vol. vi, p. 233, and vol. vn, p. 23.

*Mudgc, B. F. Notes on the Tertiary and Cretaceous Periods of Kansas, U. S. Geol. Sur. Terr. 

Ann. Kept, for 1875, pp. 277-294.

3 15 species of invertebrates, none of which have been found in the overlying strata, have been described by Meelv (U. S. Gcol. Sur. Terr., vol. ix) and White (Proc. TJ. S. National Museum, vol. II) from 

this horizon in Saline county, Kansas.
STANTON.] BLACK HILLS SECTION. 23 

THE UPPER MISSOURI HUG-ION.

The immense area of Cretaceous in Nebraska, North Dakota, South 

Dakota, arid Montana lias had little careful study excepting along the 

course of the Missouri river and around the base of the Black hills. 

The section quoted at the beginning of this paper gives a general description of the beds as developed in this region, but they are subject 

to considerable local variation and it is especially worthy of note that 

the calcareous Niobrara division disappears entirely in Montana, as it, 

does along the eastern base of the Wasatch mountains and elsewhere 

in Utah, and in southwestern Colorado.

In the Black hills the strata have been most fully described by Prof. 

Henry Newton. 1 He was able to recognize there all five of the divisions of the Upper Missouri section. The principal differences as compared with that section are the presence of several thin beds of sandstone interstratified with the upper portion of the Port Beuton shales, 

and the fact that nearly all of the divisions are much thinner. The 

estimated thicknesses are:

 Blade Mils Cretaceous section.

1. Dalcota. Feet.

Coarse yellow or rod sandstones with discontinuous variegated clays. 

Iii some places a part of the sandstone is soft and white, and at other 

localities it is changed to a dense quartz ite.......................... 250-400

2. Fort Benton.

Dark plastic clays which usually contain large quantities of alkaline 

salts and selenite. Thin bedded calcareous sandstones, containing 

numerous fossils, are frequently found in the upper pa,rt. ............ 200-300

3. Niobrara.

Gray calcareous shales and marls with some limestone; Inoceramus laliatiis and Ostrea congcsta very numerous. Thickness, roughly estimated 100-200

4. Fort Pierre.

Dark gray and bluish plastic clays with many fossiliferous calcareous 

concretions in the upper part. Thickness, estimated................ 150-250

5. Fox Hills.

Ferruginous sandstone, with Veniella Immilis, Spliosriolatransvcrsa, Idconarca sJiutnardi, etc. Thickness, roughly estimated ................... 100

According to these estimates the total thickness of the Colorado formation in the Black hills region is only 300 to 500 feet, and the entire 

marine Cretaceous section is less than 1,000 feet. It should be remembered that no accurate measurements of local sections were made. The 

following species of fossils have been reported from the Colorado beds 

of tliis region :

Ostrea congesta. Prionotropis woolgari. 

Inoceramus labiatus. Prionocyclus wyouiingcnsis. 

Inoceramus fragilis. Scaphites warreni. 

Inoceramus perplexus. Scaphites wyomingcusis. 

Inoceramus altus. Scaphites larvaiformis. 

Fusus shumardi.

1 Now ton, Henry, anil AViiltiV I'. J'omio.y, Gcul. of tlio 'Black Hills of Dakota, Wualiin^tun, 1880. The 

Cretaceous is described ou pp. 1 GO-180.
-24 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL.IOG.

In Montana the Fort Benton division of the Colorado formation is 

well represented, and the types of many of its characteristic species 

were collected in that state. According to Meek and Hayden1 this 

division attains a thickness of about 800 feet in the neighborhood of 

Fort Benton. The following species of invertebrates have been obtained within a few miles of that locality, but their exact vertical range 

in the local section has not been published:

luoceramns fragilis. Plioladoinya papyracea.

Inoceramus umbonatus. Scaphitos vermiformis.

Inoceramus exogyroides. Scaphites ventricosus.

Inoceraraus teauirostratus. Scaphites mullananus.

Inoceramus undabundus. Nautilus elegaus.

Nearly all of these have been found in the Colorado formation or its 

equivalents at other localities and none of them is known to occur at a 

higher horizon.

The geologists who have recently studied the Cretaceous coal fields 

of Montana have been unable to divide the marine portion of the Upper 

Cretaceous into distinct formations, and the collections of fossils have 

not been sufficient to indicate the paleontologic break if there is one. 

The following section, adapted from Mr. W. H. Weed's paper 2 on "The 

Cinnabar and Bozeman Coal Fields of Montana," shows the character 

of the strata up to and including the lower portion of the Laramie.

Cretaceous section of Cinnabar inounlain, Montana.

Laramie: Feet.

Sandstones, containing coal ............................................. 800

Coal seam ............................................................... 5

Sandstones, white, massive, cross-bedded................................ 125

935

Colorado and Montana:

Fissile, argillaceous sandstones and shales............................... 240

Shales, generally crumbly, with layers of black bituminous shale, and

harder sandy ledges................................................... 450

Shaly sandstones and limestones ......................................... 225

Sandstone .............................................................. 40

Sandy, splintering, gray shales and limestones ........................... 165

Black bituminous shales ................................................ 500

Limestone.............................................................. 40

Black shales, sometimes arenaceous ..................................... 400

Sandstone .............................................................. 10

Black and dark-blue shales.............................................. 250

Sandstone.............................................................. -15

Sandy shales............................................................ 75

Sandstone.............................................................. 10

1 Proc. Acad. Nat. Sci., Phila., 1861, p.421; U. S. Geol. Stir. Terr., vol.ix,p. xxix. 

"Bull. Geol. Soc. Am., vol.n, 1891, p. 352.
WANTON.] MONTANA AND COLORADO. 25

Colorado nnd Montana Continued. Toot.

Thinly laminated arenaceous shales with Ostrca anomioides ............... 340

Sandstones ............................................................... .15

Shales.................................................................. 75

D akota:

Quartzite.....................................................:......... 30

Limestone with great numbers of a, small fres! i-water giisteropod ........ 10

Sandy shales............................................................ 150

Eed earthy limestones, maguesian ...................................... 50

Conglomerate .......................................................... 40

Sandstone and shales ................................................... 95

Sandstone.............................................................. 151

526

Total Cretaceous...................................................... 4,311

Sections at other localities give a much greater total thickness, but 

the marine portion, or combined Colorado and Montana, seems not to 

vary greatly. It is evident that both of these formations are represented in the section, but there seems to be no lithologic or structural 

reason for making a division and all of the fossils yet reported from 

the locality belong to the Colorado fauna and probably all came from 

near the horizon of Ostrea anomioides. . The following species were collected there by members of the U. S. Geological Survey of the Territories.

Ostrea anomioides. Baciilites asper? 

Trigonia, related to T. evansana. Scaphites ventricosus. 

Inoceramus sp. ?

At a locality near the Missouri river below Gailatin, Montana, where 

the same beds are exposed, the first three of the above-named species 

occur, and associated with them are Corbicula inflexa, Pliarella? pealei, 

and a number of others 1 represented by casts that can not be specifically determined.

COLORADO AND NEW. MEXICO.

Along the eastern base of the Front range in Colorado the Upper 

Cretaceous formations are well developed and easily distinguishable 

both by lithologic features and by an abundance of characteristic fossils. From the northern boundary of the state to the Arkansas river 

and beyond, the first prominent " hogback," or foothill of the mountains is composed of the sandstones and conglomerate of the Dakota. 

It is so constant lithologically that it can be readily recognized Avithout 

the aid of the plants which are the only fossils that are commonly found 

in it in this region. On the plain immediately east of the Dakota ridge 

the shales and limestones of the Colorado, the softer clay shales and

1 See Prof. Moek's lists in Aun. Kept. U. S. Geol. Sur. Tore., for 1872, pp. 474,475.
26 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA, [nur.i.,106.

the sandstones of the Montana, and the coal-bearing sandstones and 

shales of the Laramie are exposed in the order in which they are named. 

There are numerous fossiliferous zones throughout the marine portion 

of the strata, and it is usually not difficult to trace the characteristic 

species of the Colorado and Montana formations, respectively, almost 

to the dividing line between the two formations.

The section given below is based on descriptions of the Cretaceous 

strata in the Denver region by Mr. Geo. H. Eldridge. 1 Although originally intended only for a limited area surrounding Denver, Mr. 

Eldridge's description with very slight modifications will apply equally 

well to any part of the Cretaceous belt between Wyoming on the north 

and Pike's peak on the south. Perhaps the Laramie portion of the section should be excepted in this statement, as it is not so well developed 

in the northern and southern portions of this area as in the Denver 

basin.

Cretaceous section in central Colorado.

Dakota: Feet, 

A thin bed of conglomerate composed of well-rounded quartzose pebbles 

united by strong siliceous cement. Hard, usually gray, sandstone 

in two prominent benches separated by a band of fire clay. Fossil 

plants are abundant at some localities. Total thickness of the formation about .......................................................... 300

Colorado:

Fort Benton 

Dark shales with frequent intercalations of fossiliferons drab limestone in the upper third. Inoceramus labiatus is the most abundant and characteristic species and Prionotropis woolgari is occasionally found .................................................. 400-500

Niobrnra 

Drab-white limestone containing Inoceramus deformis, I. labiatus, 

Ostrca congcsta, etc.............................................. 40

Gray clays and buff siliceo-calcareous shales with Ostrea conyesta 

and numerous scales of fishes.................................... 260

Total thickness of Colorado formation......................... 700-800

Montana:

Fort Pierre 

Drab shaly clays with numerous highly fossiliferons concretions 

of drab limestone and occasional unimportant bands of sandstone. 

Characteristic fossils: 2 Inoceramus cripsii, I. proximus, Avicula 

linr/uiformis, A. nel)rascana, Lucina occulentalis, Anisoinyon (several species), Ptyclwceras mortoni, P. crassum Hcteroceras (several 

species), Baculitcs ovatus, B. compressus, Placenticeras placenta, 

Splienodiscus lenticulare, ScapMtes nodosus, Nautilus delcayi, etc. 

Thickness ...................................................... 7,700

1 On some Stratigraphical and Structural Features of the Country about Denver, Colorado. Proc. 

Colo. Sci. Soc., vol. in, pp.93-97. On certain peculiar Structural Features in the Foot bill Region of 

the Rocky mountains near Denver, Colorado. Bull. Pbilos. Soc. of Washington, vol. XI, p. 249.

2 The fauna contains a large number of species the most of which are figured by Meet, U. S. 

Geol. Sur. Torr., vol. ix, pis. 11-27.
WANTON.] SOUTHERN COLORADO. 27

Montana Continued. e Feet. 

Fox HillsArenaceous clays capped l>y a bed of yellow fossiliferons sandstone. 

Fossils:' Card-runt speciosum, Mactra alia, Tancredia americana. 

Vcniclla humilis, Callista deweyi, C. oiuenana, Sphaeriola cordata, 

Liopistha undata, Anchura americana, Scaphites conradi, etc. Thickness ........................................................... 800-1,000

Total thickness of Montana formation......................... 8,700

Laramie:

Sandstones and coal beds, about................................... 400

Clays, ironstones, and rarely coal beds ............................ 800

Fossils: plants and fresh and brackish-water mollusks ............

Total thickness ...."........................................... 1, 200

The Fort Pierre shales here have a much greater development than 

in any other partof the Bocky mountain region. With this exception 

the section is almost identical with Meek and Hayden's Upper Missouri 

section.

Southward from the neighborhood of Denver the Montana formation 

becomes much thinner, until, on the Arkansas river between Canyon city 

and Pueblo, its thickness is approximately 3,000 feet. It is also less 

fossiliferous and more uniform in lithologic character, so that the Fox 

Hills is not usually recognizable as a distinct division, though the fossiliferous zone, with its characteristic species at the top of the Fox Hills, 

has been observed at Colorado Springs, and the underlying shales at 

that place and in the Arkansas valley yield some Fort Pierre forms, 

such as Inoceramus cripsii, I. proximus, Lucina occidcntalis, Baculites 

ovatus, Scaphites nodosus, Heteroceras, etc., but throughout the formation as a whole fossils are not so numerous either in species or individuals as they are in the section last described.

In the area now under consideration the Colorado formation becomes 

a more important feature of the geology on account, of the greater area 

that it covers and of the better development of its fauna. The chief 

cause of its increased area is a low anticlinal fold extending out into 

the plain as a prolongation of the axis of the Front range. The erosion 

that has planed off this fold until it is scarcely noticeable as a topographic feature has removed t<he Laramie and Montana strata from an 

area at least 25 miles wide, and at a few places along the crest of the 

fold has just reached the Dakota sandstone.2 Consequently the nearly 

horizontal shales and limestones of the Colorado form the surface over 

a large area,3 and are well exposed in long bluff's on the Arkansas, the 

Cucharas, and other streams, and also in the usual narrow belt along 

the foothills.

The characteristic Fort Benton shales resting on Dakota sandstone 

vary considerably in thickness. Near the mountains at Canyon city

1 Some of these also occur in the Port Pierre division.

8 The Dakota is exposed on the bank of Arkansas river 8 miles above Pueblo and on the plains 1.0 

miles east of Cucharas.

3 On the geological sheets of Hayden's Atlas of Colorado the area assigned to the Colorado formation 

along the Front range and in the southern central part of the state is too large on account of the fact 

that the Fort Pierre shales are all mapped as Colorado, although the legend states that they are 

included in the Fox Hills.
28 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL.IOO.

the thickness is 400 to 500 feet, but out on the plain it decreases until 

it is less than 300 feet.

About the middle of the dark shales there is always a calcareous 

zone, sometimes 40 or 50 feet thick, consisting of alternating- layers of 

shale and drab limestone, the latter full of Inoceramus labiatus. The 

upper 150 feet of dark shale frequently contains brown or drab calcareous concretions, some of which are fossiliferous. Near Carlile Springs, 

on the Arkansas river, 18 miles west of Pueblo, the upper part of this 

zone yielded the following species:

Exogyra suborbiculata. Liopistlia concentrica.

Ostrea lugubris. Turritella whiter.

Ostrea malacliitensis. Amauropsis Imlbiformis.

Inoceramus fragilis. Xeuophora sitnpsoni.

Cardinal pauperculum. Pugnellus fusiforinis. 

Veniella mortoni. . Rostellites dalli.

Anatina liueata. Prionotropis hyatti.

Above the Fort Bentori shales there is a bed of rather coarse massive 

gray sandstone which at Carlile Springs is almost 15 feet thick. It is 

here capped by 1 to 2 feet of brown calcareous sandstone containing 

Ostrea lugubris, impressions of Prionocyclus ivyomingensis, and numerous 

shark's teeth. Above this is about 40 feet of light-colored, compact 

limestone with Inoceramus deformis, I. labiatus, and Ostrea congesta, 

passing up into light gray and buff calcareous shales withOstrea congesta.

The section is essentially the same as the one in the Denver region, 

with the addition of the sandstone at the top of the Fort Benton shales. 

This new feature is not distributed over a very large area, nor is it 

constant even in the region under consideration, but it is rendered important by the fact that at some localities it is very fossiliferous and 

contains a varied littoral fauna, part of which had previously been 

known only in a limited area in northern Utah where its stratigraphic 

relations were not clear. East of the mountains this sandstone was not 

seen farther north than Colorado Springs, where it is 10 feet thick. On 

the Arkansas river above Pueblo it is from 15 to 20 feet thick. Along 

the foothills in the neighborhood of Canyon city its thickness varies 

from 4 to 10 feet. At some localities in Huerfano park, where it is very 

fossiliferous, it is 40 feet thick, and for convenience in accurately referring the species to their horizon I have there called it the Pugnellus 

sandstone on account of the abundance of the characteristic fossil, 

Pugnellus fusiformis. Usually it is a compact, massive, or heavy 

bedded sandstone of uniform texture throughout, but at the localities 

where it is very fossiliferous the fossils occur in thin bands and lenticular masses of hard calcareous sandstone, while the larger part of the 

rock is more friable and sometimes contains partings of shale.

This thin bed of sandstone shows that over a considerable area there 

was a brief cessation and probably a reversal of the downward movement of the Fort Benton sea bottom just prior to the deposition of the 

Niobra.ra limestone. Both the character of the sediments and the con-
STANTON.] HUERFANO PARK, COLORADO. 29

tained fossils indicate that the bed was deposited in shallow waters 

not for from land.

The band of brown calcareous sandstone above the Puguellus sandstone is rather more persistent, and it always contains sharks' teeth and 

impressions of Prionocyclus wyomingcnsis, and usually Ostrea lugubris. 

Its thickness varies from 1 to 4 feet.

The Cretaceous section of Huerfano park, Huerfano county, Colorado, 

is entirely similar to that of the Arkansas valley just described, but as 

it has furnished so large a proportion of the species here described it 

deserves a separate notice in order that the evidence on. which these 

species are referred to the Colorado formation may be given.

The "park" is a synclinal basin almost surrounded by the uplifts of 

the Wet mountains on the east and north and of'the Saugre De Cristo 

range oil the west and southwest, The central and larger portion of 

this basin is filled by a thick series of sediments of Eocene and later 

Tertiary age.1 The Cretaceous strata are exposed at many places 

around the margin, especially on the east, north, and west sides. The 

entire series from the Dakota to the Laramie, inclusive, is represented, 

but the Montana and Laramie are not often well exposed.

The fossils were nearly all collected from a single bed, the Pugnellus 

sandstone, which is easily recognized in all its outcrops both by its 

position and by its fossils. The most prolific localities examined are 

near Qnillian's ranch on Williams creek, on Muddy creek about 10 miles 

above Gardner post office, in Poison canyon, and near Malachite postoffice on the north side of Huerfano river. The Pugnellus sandstone ab 

these four localities has yielded the following list of species, the majority of which were found at all the localities:

Ostrea lugubris. Mactra huerfa.iicrisis.

Ostrea inalachitensis. Turritella whitei.

Exogyra suborbicnlata. Xenopliora simpsoni.

Anomia snbquadrata. Gyrodcs clepressa.

Gervillia proploura. Gyrodes conradi.

Avicula gastrodcs. Amauropsisbulbifonnia.

Inocerarnus labiatus. Mesostouia occideutalis.

Inoceramus fragilis. Pugnellus fusiformis.

Soleinya? obscura. Fusus (Neptuuea?) vonenatus.

Pinna petrina. Tritoiridea? huerfancnsis.

Yoldia subelliptica. Fasciolaria? (Cryptorhytis) utahcusis.

Trigonarca obliqua. ' Pyropsis coloradocnsis.

Lucina juvenis. Rostellites dalli.

Cardium pauperculum. Rostellites ambigua.

Tapes cy primer ifor mis. Rostellites gracilis.

Legumen? . Cancellaria malachitcusis.

Tellina (Palteomcera) whitei. Actaeon prop hi qu us.

Siliqua huerfanensis. Hamiuea truncatit.

Pholadomya coloradoensis. Placcnticeras .

Anatina lineata. Prionotropis hyatti.

Liopistha (Psiloniya) concentrica. Cassidulus stantoni.

Mactra eraiuousi.

i HillB, E. C.: Tertiary beds of the Haerfano river basin, Proo. Colo. Sci. Soc., vol. in, 1800, pp. 

W8-1M, 217-223..
30 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. IBULL.IOO.

It should be noted that this list contains 13 of the 14 species collected 

from the upper part of the undisturbed Fort Benton shales in the 

Arkansas valley.

The stratigraphic evidence that the Pugnellus sandstone is near the 

top of the lower division of the Colorado formation is equally conclusive. A section measured on Muddy creek gives the following succession of strata in ascending order : 

Dakota: Hard brown and gray sandstone with plant remains, not fully exposed.

Feet. 

Colorado:

Dark clay shales...................................................... 100

Gray limestone in thin bands alternating with shale. Inoceramus labiatus abundant....................................................... 30

Dark shale........................................................... 300

Rather coarse gray and yellowish sandstone, becoming shaly above, 

with occasional very fossiliferoua bands and lenticular masses containing the species listed above................ ..................... 40 to 50

Brown calcareous sandstone with Ostrea congesta, Prionocyclus wyomingensiSf and shark's teeth ........................................ 4

Light drab limestone with Inoceramus deforms, I. laUalus, and Ostrea 

congesta passing up into calcareous shales...........................' 75

Total thickness of Colorado exposed ............................... 559

Other localities in the park show that the upper bed of limestone is 

overlain by 300 to 400 feet of light gray or buff calcareous shales, succeeded by the drab clays of the Montana formation, with a probable 

thickness of 3,000 feet. The latter have yielded specimens of Inoceramus proximus, Lucina occidcntalis, Baculites ovatus. Ptychoceras, and a 

few other characteristic forms.

The southern continuation of the Arkansas valley Cretaceous area. 

in Colorado and northeastern New Mexico has been described by Dr.

J. S. Newberry,1 Prof. J. J. Stevensou,2 and others.3 From these descriptions it is evident that the Colorado formation there retains about 

the same lithologic and paleontologic features as in the region above 

described, excepting that the Pugnellus sandstone with its shallowwater fauna has not been noticed, and there seems to be a greater proportion of limestone throughout the formation.

Dr. Newberry states that on the banks of the Canadian river4 the 

"Middle Cretaceous" exposures are from 800 to 1,000 feet thick, consisting mostly of blue limestone interstratified with dark blue and

1 Macomb's exploring expedition from Santa F6, N. Mex., to junction of Grand and Green rivers. 

Geol. Kept., Washington, 1876, pp. 32-35.

1 TT. S. Geog. and Geol. Surveys west of the One hundredth meridian, vol. HI. Supplement, pp. 88-158. 

and Am. Geologist, vol. HI, pp. 391-397.

3 Prof. Jules Marcou visited this region in 1853 in connection with the Pacific railroad surveys, and 

his observations were published in v.ol. in of the reports of that survey, in the Geology of North America, Zurich, 1858,^and elsewhere. In an article on "the Mesozoic series of New Mexico" (Am. Geologist, vol. iv, 1889, p. 155-165 and.216-229).the same author gives titles of.most.of. the geological ropdrt,-* 

relating to New Mexico..

4 Op. cit., p. 33.
BTASTOH.] NEW MEXICO AND COLORADO. 31

Brownish bituminous and calcareous shales. Inoccramus labiatus and 

Qryplma newberryi 1 range from bottom to top of this series, and in the 

upper portion Inoceramusfrar/ilis, Ostrea congesta, 0. elegantula, Prionotropis woolyari, etc., also occur.

In western New Mexico and southwestern Colorado the Cretaceous 

section contains no limestones, or only very thin bands of local extent 

that are seldom exposed, and the same statement will apply to the 

entire area between the Continental Divide and the Wasatch mountains. The calcareous beds of the Niobrara division *that have served 

as a convenient reference plane in all the region east of the mountains 

are absent. The section in the area drained by the San Juan river 

naturally falls into three lithologic divisions, the lowest of which is a 

series of coarse sandstones, with some beds of shale, and in the upper 

portion one or more coal beds. The middle division consists of dark 

clay shales, 1,200 to 1,500 feet in thickness, and is overlain by a thick 

series of. coal-bearing sandstones, shales and marls forming the upper 

division. These are the members of Dr. dewberry's general section, - 

and similar divisions have been made by other geologists who have 

described the region, though they have sometimes been still further 

subdivided, and there have been differences of opinion as to the correlation of certain parts of the section with the formations east of the 

mountains. All have agreed, however, that the sandstones at the base 

(or at least the upper part of them) belong to the Dakota formation 

and that the Colorado formation is represented in the shales of the 

middle division.3

Here and in other portions of western Colorado the larger part of the 

coal-bearing sandstones and shales of the upper division was referred 

to the Fox Hills group by the members of the Geological Survey of the 

Territories, and it is so mapped in Hayden's Atlas of Colorado, thereason 

for this reference being that marine Cretaceous (Fox Hills) fbssils were 

 found at various horizons above the coal beds.4 Others have refeired 

all of the productive coal measures of this area to the Larainie,5 basing 

their correlation on the stratigraphy, the lithologic character of the beds, 

and the evidence of the fossil plants. There is no doubt that Fox Hills

1 Throughout this bulletin the names of fossils are usually changed so as to conform to the noinenclature adopted in the descriptions that are to follow. Grypliona, nmvbemji is the Upper Cretaceous 

form so frequently referred to in Dr. Newberry's report under the name Gryp-hcva pitcheri.

2 Op. cit.,p.32.

3 It should bo remarked that the molluscan fossils reported by Dr. Newberry from the lower division seoni to belong with the fauna of the overlying shales, and in southern Utah the coal-bearing 

sandstones at the base of the Cretaceous have yielded fossils that I regard as a part of the Colorado 

fauna.

4 JTor detailed sections and descriptions of Cretaceous in southwestern Colorado, soo report of W. H. 

Holmes in Ann. Kept. U. S. Geol. Sur. Terr, for 1875, pp. 242-207.

In western Colorado: Reports of A. C. Poale, idem, for 1874, pp. 128-155, and for 187G, pp. 170-180; of 

C. A. AVhite, ibid., pp. 19. 28-34, and other reports in the same scries.'

5 Lakes, A.: Geology of Colorado coal fields. Ann. Kept. State School of Mines, Denver, J889, pp. 

19, 148, 162, etc.

Hills, R. C.: Orographie and structural features of Rocky mountain geology. Proc. Colo. Sci. Soc. 

vol. in, 1890, p. 380 ot seq.
32 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL.ICO.

species of fossils have been found at several places well np in the series. 

I have collected Inoccramus cripsii, Mactra alta, Cardium, BacuUtcs 

compressus, and. Placenticeras placenta, var. intercalaris, in Man cos canyon 

from a bed that seemed to be 800 to 1,000 feet above the base of the 

coal-bearing sandstones. No evidence of faulting was seen there. It 

is beyond the scope of this paper, however, to discuss either the age of 

these upper beds or the more general subject of the delimitation of the 

Laramie formation. There is need of much detailed Avork in some parts 

of the supposed Laramie area, and the evidence from all possible sources 

must be collected and considered before the latter question can be dismissed with a final solution.

The shales of the middle division attain a thickness of 1,200 to 1,500 

feet in the Sa,n Juan valley, and farther north in western Colorado they 

are still thicker. It has already been intimated that these shales are 

of much the same character throughout and are apparently the product 

of continuous sedimentation, but the characteristic fossils of the Colorado formation are confined to their lower half. The upper half is 

usually barren of fossils, though a few species belonging to the Montana fauna have been found at the top. Along the Mancos river north 

of Mesa Verde and in the valley of Animas river where I have made 

collections the fossiliferous zones are as follows :

Feet.

1. Soft dark.cla.y shales resting on Dakota sandstone. Numerous specimens of

Gryphaca ncwberryi iu upper portion ..................................... 120

2. Light drab argillaceous limestone "with Inoccramus labiatus. This is seldom

exposed and probably not continuous.................................... 4-6'

3. Dark clay shales with a large Inoceramus covered with Ostrea congesta, and 

calcareous concretions, a few of which contain Inoceramus and Jiaculitcs 

gracilia? ................................................................. 250

4. Thin bands of brown arenaceous limestone and occasional concretions alternating with shales. Fossils abundant, including Inoceramus labiatus, I. 

fragilis, I. dimidius, Ostrea lugnbris, and Prionocydus macombi ............ 8-10

For about 200 feet above this zone there are fragments of a large 

Inoceramus, apparently like I. deformis, covered with Ostrea congesta. 

No fossils were found in the 600 or 700 feet of shales above this horizon.

Although the fauna of these beds is not large it contains several 

characteristic species and it is believed to prove that the fossiliferous 

beds above described are the approximate equivalent of the Colorado 

formation and that the overlying shales should not be included in that 

formation. Wherever fossils have been reported from the upper half 

of the shale division in western Colorado and eastern Utah they are 

of Montana formation species and the two faunas never seem to be 

blended 1 in that region.

Northward, in the valleys of Grand and Gunuison rivers and their 

tributaries in Colorado and of Green and Price rivers in Utah, the

1 Mr. W. H. Holmes reports the occurronce of Scaphites loarreni, Inoccramus barabini, and Baculites 

. ovatus in the same bed on the Sau J nan river from about the horizon of the zone No. 4 above described. 

I have been utable to find this collection, but 1 have reason to believe that the last two species were 

incorrectly identified.
STANTON.] NEW MEXICO AND COLORADO. 33

Colorado formation is still mainly composed of dark clay shales, though 

there are occasionally thin intercalations of sandstone. A section on 

Gunnison river, opposite Koubideau's creek, described by Dr. Peale. 1 

which shows the general character well, is as follows:

Feet

1. Shaly sandstones, with Intel-laminated argillaceous beds, extending from"] 

the top of the bluff on the river to the base of (he first bluff north of j 

the river. The beds are for the most part concealed................... I 175

2. Coarse yellow sandstone T\ ith calcite .................................. [

3. Gray laminated sandstone.............................................. J

4. Thin lamince of grayish sandstone shales, with fine "black argillaceous shales, 

gypsiferous and calcareous, containing Inoceramus, Os'rea luyiibris (Conrad), and other Cretaceous fossils....................................... 125£

'5. Yellowish sandstone shales, with quantities of Inoceramus and Ostrea especially abundant near the top, where there is a layer of black shales....... 40

6. Black argillaceous shales, partly concealed by d6bris ..................... 38

7. Coarse yello.w, gypsiferous, and calcareous sandstones, with layer at top, 

breaking into pencil-like pieces one to two inches long and an eighth of 

an inch in thickness .................................................... 50J

8. Sandstone shales ....................................................... \

9. Fine black argillaceous shales ........................................... \

10. Coarse yellow calcareous sandstone, resembling that described under No. 7. 1

11. Fine black argillaceous shales, with bands of sandstone (fossiliferous), species of Inoceramus and Ostrea .......................................... 36

12. Hard gray sandstone ..................................................... 1

13. Very fine soft black argillaceous shales, with a few laminae of gray sandstone. In the lower part of the group the shales are coal-black, but as 

we ascend they become gray-black. Nearly all the layers are fossiliferoiis. Among the forms are Prionovyclus wyomiugerisis, Soaphites [ivarrcni], 

and Inoceramus [labiatus']. They are especially abundant near the top... 66-J14. Fine gray and yellowish shales ........................................... 34

15. About 17 feet of gravel, composed largely of basaltic bowlders, forming the 

top of the bluff.

Total, about........................................................... 687i

These shales rest on sandstones referred to the Dakota. In this district Dr. Peale estimates the total thickness of the shales belonging to 

the Fort Benton, Niobrara, and Fort Pierre at 1,500 to 2,000 feet.

A large part of Castle valley in eastern Utah is underlain by shales 

like those above described, and at a horizon in them about 1,000 feet 

below the Montana sandstones exposed to the Book Cliffs I have collected Prionocyclus wyomingensiSj Scaphites ivarreni, Bacidites gracilis ?, 

and Inoceramus dimiclius.

Farther south in western New Mexico and in Arizona, the sections 

described by Mr. G. K. Gilbert,2 contain a greater proportion of sandstone, but the lower 850 feet, which is the only portion from which 

fossils were obtained, evidently belongs to the Colorado formation, and 

perhaps in the'lowest layers to the Dakota. The highest fossiliferons 

horizon noted is at Stinking spring, near Fort Win gate, New Mexico, 

and it yielded Inoceramus labiatus and Ammonites.

1 Ann. Rept. U.S. Geol. Sur. Terr, for 1874, p. 130.

2 U. S. Geog. and Geol. Sur. West«no huiulrcdtli meridian, vol. in, pp. 544, 549-554.

Bull. 106 3
34 COLORADO FORMATION AND .ITS INVERTEBRATE FAUNA. [BULL. 106.

UTAH.

A portion of the Cretaceous in Utah has already been incidentally 

described, but two other areas in that territory require separate treatment on account of differences in both lithologic and paleontologic characteristics. One is the neighborhood of Coalville, in northern Utah, 

and in connection with it certain small areas in southwestern Wyoming 

may be conveniently discussed. The other is an irregular belt extending across the high plateaus of southern Utah, just south of the escarpment of the Pink cliffs.

In the area last mentioned several .sections have been described by 

Messrs Gilbert1 and Howell,2 which show a tripartite division of the 

Cretaceous like that in the San Juan area with which it is geographically connected, but here the lower division of sandstones carries the 

.principal coal beds, while the upper division 'has only thin seams. 

Other differences worthy of note are the occurrence of many marine 

fossils in the sandstones near the base of. the Cretaceous and the more 

varied tauna of the lower part of the shales.

Some years ago Mr. C. D. Walcott measured a section in Kanab valley and made a considerable collection of Cretaceous fossils there. He 

has generously placed in my hands his unpublished notes on theMesozoic portion of this section, and the description given below is based on 

these notes, supplemented by my own observations made during the 

summer of 1892, while studying the same section and a neighboring one 

in Long valley. The measurements are all Mr. Walcott's, but the detailed subdivisions are not given.

Cretaceous section of Upper Kanab valley.

Feet.

1. Alternating beds of light-colored saudstoues,clay shales, arenaceous shales, 

and coal, the sandstones constituting about one half of the entire thickness. At the base is a thiu, irregular band of conglomerate and coarse 

sandstone resting on softer sandstones and shales that are provisionally 

referred to the Jurassic. Leaves and other plant remains occur about the 

middle of the division, and two zones near the top contain numbers of Corbula nematophora, Cardiitm paitpei ciilum, Modiola multilinigera, Glaucoma 

coalvillcnsis, a small Ostrea and an Anomia. Thickness................... 330

2. Arenaceous and clay shales, mostly of a drab color weathering into rounded 

hills and slopes of soft, more or less sandy clay. Near the base the shales 

are slightly bituminous and contain many, limestone concretions, some 

'of which are filled with well preserved fossils. (Seelist below.) Thickness. 885

3. Rather coarse friable sandstones of light colors (white, gray, and buff), 

alternating with thinner beds of gray, drab, and purplish arenaceous 

shales. The lower 50 feet is a massive yellow or buff sandstone, which is 

overlain by 50 to 60 feet of softer very fossiliferous sandstones, containing 

great numbers of Ostrea solcniscus, Admclopsis (an uudescribed species), 

Modiola multilinigera f, Cyrena, Anomia, and a few others, while the upper 

portion contains plantremains with Unio kolmesianus, Viviparuspangmtcliensis, Planorbis Physa, etc./.tuat seem to belong to the Laramie. Thickness.. 1, 700

i Op. cit., pp. 158-160.

2 Ibid, pp. 270-280. Button's "Geology of the High Plateaus of Utah " anil " Tertiary History of the 

Grand Caflon District" contain good general descriptions of the stratigraphy.
STANTON.] SOUTHERN UTAH. 35

The coal beds of the lower division vary greatly, both in number and 

thickness, in sections only a few miles apart. The coal seems to be of 

inferior quality, but all of the few openings that have been made are 

small and have not gone beyond the influence of surface weathering. 

A mine at GUendale, in Long valley, on the uppermost coal bed, which 

is near the top of the division, shows about 8 feet of coal with two 

partings of indurated shale. One of these near the base of the bed is 

full of Unios, while the other about 3 feet above it contains great numbers of Gorbtda nematophora.

The fauna of this division so far as it is known is the same as that of 

the lower portion of the section at Coalville, Utah, and of the coalbearing series along the western edge of the high plateau region near 

Cedar city and Kanarra, which will beconsidercd on following pages.

The general aspect of the middle-division is that of drab clay shales, 

though the upper partis more arenaceous and forms a transition, to the 

sandstones above. The fossiliferous concretions seem to be confined to 

the lower 40 feet in Kanab valley, but near Mount Carmel in Longvalley a few concretions containing Buchiceras swallovi, Liopistha mceki, 

and associated forms were found np to 325 feet above the base. This 

zone has yielded an interesting fauna containing some species not yet 

found elseAvhere, with others that connect it with the Colorado fauna 

as developed inHuerfano park and in the Eagle Ford shales of Texas, 

as the following list of those collected in Upper Kanab valley will 

show:

Gryphtea newberryi. . Lnnatia ccracimia.

Lima utaliensis. Anchnra? pvolabiata.

Camptonectes platessa. Anelmra ruida.

Inoceramus fragilis. Tritoiiiuni-kanabenso.

Nemodon sulcatinus?. Sigavetus textills.

Lucma snbnndata. Helicoccras paricnse.

Liopistha meeki. Baculites gracillsf

Liopistha olongata. Buchiccras swallovi.

C orb ul a kanabensis. Placenticcras.

Tnrritella wlutei. Acantlioceras kauabenso.

At a locality southeast of Paria, Utah, a number of the above species 

have been found in the same zone and associated with them Inoccramus 

labiatus, Yeniella, yoniophora, and Serpula intrica.

This list of fossils contains enough characteristic species to furnish a 

good basis for correlation with the lower part of the Colorado formation, but with our present knowledge it is impossible to locate the upper 

limit of the formation in this section. It should probably be drawn 

below the base of the upper sandstone division.

The upper part, and probably almost the whole, of the third division 

has been correlated with the Laramie with a reasonable degree of certainty. The testimony of the fresh-water invertebrates and of the 

plants, though rather meager, is all favorable to such a correlation, and 

the fact that it is overlain by Eocene Tertiary beds without apparent
36 COLOEADO FORMATION AND ITS INVERTEBRATE FAUNA, [nun. 106.

stratigraphic break also points in the same direction. The fossiliferons 

beds at the base, however, contain only marine- and brackish-water 

species, and unfortunately these do not furnish a good basis for correlation with any zone in other Cretaceous sections. There is a great 

abundance of fossils, but only a few species are represented and some 

of these are forms that have great vertical range, while the others have 

not been found outsfde of this district. The fauna as a w.hole has some 

resemblance to that of the upper coal horizon (the " third ridge") at 

Coalville, Utah, which, as will be shown farther on, is fully 1,800 feet 

below the top of the marine Cretaceous there, but this resemblance can 

not be accepted as proof of their contemporaneity. In Kanab valley 

the marine forms were not found more than 100 feet above the base of 

the sandstone, but in Long valley, only a few miles distant, they occur 

100 feet higher. At the former locality fossil plants are abundant in 

a band of sandstone 275 feet above the top of the fossiliferous marine 

beds.

The sandstones above the basal massive bed have about the same 

character throughout. They are rather coarse, in a few instances 

becoming pebbly conglomerates, and often so friable as to form soft 

slopes that are easily mistaken for shale exposures. Many of these 

sandstones are large lenticular masses rather than continuous beds 

and nearly all of them vary greatly in thickness within short distances, 

a peculiarity that often makes it difficult to recognize individual beds 

in two neighboring exposures.

From the above remarks it will be seen that both the -Montana and 

the Laramie formations are believed to be present above the Colorado, 

but the lower limit of each of them is still undetermined.

Before leaving the consideration of the Cretaceous in the high plateaus of Utah the differences shown on the western escarpment at Cedar

city and Kanarra should be mentioned. At these places the equivalent of the lower coal-bearing division of the Kanab section has a much 

greater development and the other two divisions if present are concealed by a sheet of eruptive rock. At both localities the lower 300 or 

400 feet consist of gray and brown sandstones and sandy shales in 

which no fossils were found excepting fragmentary remains of dicotyledonous plants. Then comes a band of fossiliferous gray shale 30 feet 

in thickness with a seam of coal at its base and a thicker coal bed 

above it. The fossils are Ostrea soleniscus, Cardiumpaupercithim, Barbatia micronema, Corbtda nematophora, Cyrena , Admetopsis rhomboides, Jflulimella funicula, Gliemnitzia? and in some layers Unio.

The coal bed immediately above varies in thickness from 6 to 10 feet 

at different openings. The overlying beds, of which about 350 feet 

are exposed at Kanarra and fully twice that thickness at Cedar city, 

consist of light gray and brown sandstones with some bands of shale. 

Corbula nematophora, Ostrea soleniscus, and Admetopsis rliomboides 

occur in great numbers at several horizons up to the top of the series.
BTANTON.] NORTHERN UTAH. 37

Specimens of Inoccrnmns lalnaltis and Avicula gctfstrofles were found 

about 500 feet above the principal coal bed.

The greater thickness of the lower sandstone division here is an indication that the western border of the sea may have been near during Cretaceous time. Possibly a part of the shales of the Kanab middle division afe here represented by sandstones, and the earlier fauna, 

thus finding a congenial habitat on the sandy bottom, may have survived much longer than it did a little farther east, where the subsidence 

was greater. If this supposition be granted it will explain the fact 

that most of the fossils in the up'permost marine bed of theKanab section are closely related to species that occur 1,000 feet lower, although 

they are not found in the inter veiling strata. They have traveled across 

the area and back again as the shallow waters in which they lived

shifted their place,

Cretaceous strata with coal beds and the same species of fossils as 

those above named in the shale below the coal are exposed in 'small 

outcrops among the eruptive rocks near Iron city, 20 miles west of 

Cedar, and they are known to occur on the same meridian farther south. 

ISTo Cretaceous exposures are known to occur between this locality and 

the western slope of the Sierra Nevada.

The coal-bearing Cretaceous beds exposed at Coalville, Utah, and 

on Bear river, nea,r the mouth of Sulphur creek, Wyoming, have been 

the subject of considerable discussion, and various opinions concerning 

their precise age have been published by the several geologists and 

paleontologists who have visited the localities or examined collections 

from them. They were referred to the Cretaceous by Messrs. Meek 

and Engelmaun J in 1860 and were compared with certain Cretaceous 

beds at the mouth of Judith river, then regarded as belonging to No. 

1 (Dakota) but afterward proved to be of Fox Hills age. WhenCapt. 

Simpson's report 2 was published in 1876 Mr. Engelmaun again expressed 

the opinion that these beds are probably "Lower Cretaceous " [Dakota].

They were at first regarded as Tertiary by Messrs. Hayden 3 and 

Lesquereux.4 In 1870 Messrs. Meek and Hay den 5 adopted the view 

that the Coalville beds are Cretaceous but that they "occupy a higher 

horizon in the Cretaceous than even the Fox Hills beds of the Upper 

Missouri Cretaceous series."

Mr. Meek visited Coalville in 1872, and after making larger collections and studying the stratigraphy he decided that the entire Upper 

Missouri Cretaceous section with peril aps some older beds is represented here. The detailed section that he published G shows correctly 

the essential features of the stratigraphy. The opinions that he then

1 Proc. Acart. Nat. Sci. Plrila., Vol. xu, p. 130.

2 Exploration across the Great Basin of Utah in 1859, p. 291.

SAiiii. Kept. TJ. S. Geol. Sur. Terr, for 1869. p. 91.

« Idem for 1873, pp. 3G6,371.

8 A.uu. Kept. U. S. Gcol. Sur. Terr, for 1870, pp. 1C8,291. Iilem for 1871, p. 377.

«Auu. Kept. TJ. S. Geol. Sur. Terr, for 1872, p. 439.
38 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL.106.

expressed concerning the correlation of these beds were repeated in 

subsequent publications. 1

Messrs. King and Emmoris 2 assigned the Cretaceous strata at Coalville to the Colorado, Fox Hills, and Laramie formations, and so mapped 

them in the atlas accompanying their report. The principal (lower) 

coal bed is included in the Colorado formation and upper one in the 

Fox Hills, the line between these two formations being drawn in the 

second ridge above the lower coal bed. It should be remembered that 

the Colorado formation was then made to include the Fort Pierre 

division.

Dr. C. A. White studied the section in 1877, and after discussing the 

fossils collected in it he states 3 that it is impracticable to refer the 

strata to any one or more of the established Cretaceous groups with 

certainty, but he thinks there is no reason to doubt that the greater 

part of the series at least is referable to the Fox Hills.

The entire series at Coalville is characterized by heavy beds of lightgray and yellowish sandstones alternating with clay shales and other 

soft strata. Consequently, as the beds have a considerable dip, the 

sandstones form prominent ridges, and these were numbered in Prof. 

Meek's section, beginning with the first one above the lower coal bed. 

There are several faults in the a.rea, one series nearly parallel with the 

strike and another almost at right angles with it, but they do not complicate the section greatly since the prominent sandstones are all fossiliferous and therefore easily identified. The following somewhat generalized description will serve to shoAv the range of the fossils and the 

reasons for the correlation that follows:

Cretaceous section at Ccahille, Utah.

Feet.

1. Interstratified sandstones and shales, with heavy bed of coal at the top.

The underlying beds are cut off' by a fault, Several of the sandstone

layers are very fossiliferous. (See list below.) Estimated thickness. 500-600

2. Gray sandstones 30 feet thick forming roof of coal bed, overlain by

dark clay shales with numerous specimens of Jnoceramus labiatus ..... 795

3. Gray and yellowish hard sandstone forming the first and second ridges, 

with numerous fossils, many of which are identical with species of the 

Pngnellus sandstone in Huerfano park, Colorado. (See list below)... 100

4. Clays, with thin beds of sandstone..................................... 165

5. Massive conglomerate ................................................. 60

6. Mostly covered, but showing soft clay shales and thin beds of coarse

sandstone where exposed............................................ . 845

7. Clay shales interstratified with thin bands of sandstone and two or three 

thin seams of coal (including the Carlekm bed) of no economic importance, near the base. Fossils abundant, including marine, brackish 

and fresh water invertebrates, and plants. (See list below).......... 110

!'U. S. Gool. Sur. Terr. Vol. ix, p. xxx; TJ. S. Geol. Expl. Fortieth Parallel, Vol. iv, p. VI, footnote.' 

2 IT. S. Geol. Expl. Fortieth Parallel, Vol. i, pp. 316-319, 327-330, and Vol. n. pp. 330-337. 

8 Ann. Ecpt. U. S. Geol. Sur. Terr, for 1877, p. 239.
STANTON.] NOETHERN UTAH. 39

Feet.

8. Massive gray and yellowish sandstone forming the third ri'rlgo, with Ostrea solcnisciis, Pholadomya 8ttZn;e«<ricosa(?), Cardium, anil a few other 

marine Cretaceous species ........................................... 200

9. Mostly covered, but evidently underlain by shales aud soft sandstone. 

A baud of sandstone about the middle of this member yielded specimens of Maclra, Cardium, and Poclcit. Thickness about.............. 1,500

10. Gray and brownish sandstone, with bands of shale. The upper 30 feet 

is a massive, irregularly bedded brownish sandstone with many specimens of J'noceramns erectas, Cardium, Oslrea. and a few other species 

mostly in the form of casts ........................................... 150

The beds above this horizon are shown by the few exposures to consist of shales and beds-of soft coarse sandstone with bands of conglomerate in the upper portion. I estimate that there is room for 1,500 

feet of strata below the Tertiary Echo canyon conglomerate.

From No. 2 to No. 10, inclusive, the strata were measured by means

of a clinometer compass in the manner described by Mr. 0. D. Walcott. 1 

The thicknesses given are therefore reasonably accurate, the principal 

source of error being the possible variations in dip within the long 

covered spaces. 

The following species have been found in No. 1 of the section:

Ostrea soleniscus. Gyrodes dtvpressa.

Modiola inultilinigera. Amauropsis coalvillensis.

Inoceramus labiatus. Glaucoma utahensis.

Barbatia micronema. Tnmtolla micronema.

Trigonarca obliqua. Neritina pisum.

Cardium pauporculuin. Neritina patelliformia.

Mactra ntaheusis. Chemuitzia coalvillonsis.

Mactra emmonsi. Eulimella funicula.

Parapholas sphenoidens. Admctopsis rhomboides.

Siliqua huerfanensis. Admetopsis subfusiformis. 

Corbnla neiuatophora. . Fuijus gabbi.

No fossils have been found in the lower 300 feet of the section, and 

nearly all of those above enumerated occur in a zone from 100 to 150 

feet below the principal coal bed. Several of the species are very 

abundant in certain layers of the sandstone.

The thin bed of sandstone immediately above the coal is usually barren/of fossils. The only species that have been observed in it are Ostrea 

soleniscus and Inoceramus labiatus. The overlying thick .bed of soft 

shales constituting the larger part of No. 2 is seldom seen in natural 

exposures but two or-three shafts have been dug in it while prospecting 

for coal aud the shales thus thrown out show large numbers of Inoceramus labiatus.

Certain bands in the heavy bedded sandstone of No. 3, especially 

near the top, are very fossiliferous. At Coalville this bed is repeated 

by a fault so that it forms the first aud second ridges, but in addition to 

the structural evidence of the presence of a fault the fossils plainly 

show the repetition. On Grass creek, about 4 miles from Coalville, this

Tree. IT. S. National Museum, Vol. xi, 1888, p. 447.
40 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. I BULL. 108.

part of the series is unbroken. This horizon has yielded the following 

species of fossils:

Gervillia propleura. Corbula nematopliora.

Cardium pauperculuin. Gyrodes tlepressa.

Tapes cyprimeriformis? Tnrritella micronema.

Donax oblouga. Pugnellns fusiformis.

Tellma? isoneina. Fasciolaria? utaliensis.

Tellina modesta. Pyropsis '.

Mitctra emmonsi. Prionotropishyatti?

Anatina liueataf 4 Placeuticeras .

On East Oanou creek below Parley's park, about 12 miles southwest 

of Coalville, there are Cretaceous outcrops in which few of the individual beds of the Coalville section can be recognized, but this sandstone 

(No. 3) is present and easily recognized by its fossils, of which it has 

yielded the following species:

Trigonarc.a obliqua. Mactra eiumonsi. 

Cardium panperculum.. Pngnellns fusiformis. 

Tellina? isonema. Bacnlites gracilis? 

Tollitia? subalata. Prionotropis. 

Mactra ntaheiisis.

This outcrop was mapped by the Fortieth Parallel Survey as very near 

the boundary between the Cretaceous and the Tertiary, but it is at 

least possible that the heavy bed of coarse conglomerate 275 feet above 

it and in the same conformable series also belongs to the Cretaceous 

and simply represents a greater local development of the conglomerate 

No. 5 of the Coalville section.

The lists of fossils just given clearly show that a single fauna ranges 

from near the base of the section at least to the top of No. 3, through 

over a thousand feet of strata. It is true that certain species seem to 

be confined to particular strata, but other species, and among them 

some of the most characteristic ones, such as Inoceramus Icibiatus, range 

through nearly the whole thickness and each zone is connected with 

the others by interlocking.species. The lists also show that certain of 

these zones are represented in other sections already described. For 

example, No. 1 contains about all of the species that were found in the 

lower division of the Upper Kanab section and in the coal-bearing beds 

near Cedar city and Kanarra, and these strata may be regarded as 

equivalent. Again, the faunal lists from No. 3 and from the Pugnellus 

sandstone in Huerfano park, Colorado, have so many species in common that there can be little doubt that these beds are very nearly contemporaneous deposits.

Up to this horizon the Coalville section very clearly belongs to the 

Colorado formation 1 and apparently represents almost the whole of it 

as developed elsewhere. In Colorado there is never more than 300 to 

400 feet of the Niobrara beds above the horizon of the Pugnellus sandstone. Still it is well to remember that the Niobrara consists largely

1 The Word "formation" is hero used, iu a somewhat loose sense for want of a better term to deaig 

Date a series of strata containing a single £auna.
STANTON.] NORTHERN UTAH. . 41

of calcareous deposits which may be represented elsewhere by.a much 

greater thickness of shales and sandstones. Provisionally I have taken 

the base of the conglomerate No. 5 as the top of the Colorado formation at this locality. The soft strata of No. 6 are seldom exposed in 

the Coalville area and no fossils have been found in them, but they 

appear to belong with No. 7.

The overlying 1,800 feet of shales and sandstones are fossiliferous at 

several horizons, but their strict paleontologic correlation with Cretaceous formations of other regions is difficult for several reasons. In 

the first place several of the most abundant and best preserved species 

are not known to occur in well defined formations elsewhere. Others 

again belong to types that are known to have a great vertical distribution and many are not sufficiently well preserved to admit of positive 

specific determination, And finally, after allowance has been made for 

all these defects, the evidence seems to be conflicting. Stratigraphically it is evident that these beds hold the position of the Montana 

formation, but whether they should all be referred to that formation or 

part of them should be regarded as the time equivalent of the Laramie 

must still be left an open question. It is a question that may have an 

important bearing on the more general problem of the.condition of the 

continent during the Laramie epoch. A very promising field for the 

study of this question is in western Wyoming along the uplift of "Oyster ridge" and west of it, where at least a part of these upper beds and 

the horizon of the Evansto'u coal are both, represented in the same 

neighborhood.

Before giving the lists'of fossils -from these upper beds I will state 

that there is no doubt concerning their relative positions. The sand- 

.stones of No. 8, dipping 20° to 25°, form a nearly vertical escarpment 

beneath which the softer beds of No. 7 are exposed in a steep bare 

slope showing in some places almost every layer. The lower 25 feet 

of No. 7 exposed beneath the coal -bed yielded:

Ostrea coalvillensis. Corbula sub trigon alia?

Anomiapropatoris. Cardhim.

Modiola multilinigera? Barliatia.

The clay shales immediately associated with the coal seams contain 

large numbers of fossils in which fresh water, brackish water, and 

marine forms are commingled. The following list includes those 

recorded by Prof. Meek from the old Carleton coal mine, nearly all of 

which have been collected by myself at another exposure on the opposite side of the Weber river, and about 3 miles distant:

Modiola multiliiiigera? Neritma barmisteri.

Anemia propatoris. Eulirnelhi? dirysallis.

Cyreiia carletoni. Eulimella? inconspicua.

Uuio. Melampus antiquus.

Turritella spivonenia. Valvata nana.

Neritina bellattfla. Pliysa carletoni. 

Neritina carditoides.
42 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL. 106.

For about 50 feet above the coal seams the following species are 

found, the most of them in abundance:

Ostrea coalvillensis. Eulimella chrysaljis. 

Anoiuia propatoris. Aclmetopsis. 

Corbnlasub trigonal is? Chemuitziaf 

Cyrena or Corbicula. Melauia. 

Avi cnla.

Four feet below the highest band in which these species were found 

there is a layer of sandstone containing plant remains. They were 

very abundant and fairly well preserved at one small outcrop, where a 

collection was made. Plants, also occur sparingly in other'bands of 

sandstone above this and in the inassiv<e sandstones of No. 8. The 

plants have been examined by Mr. F. H. Kuowlton, of the Geological 

Survey, and in his notes on them he says:

The matrix, a hard, fine-grained brownish sandstone, preserves the outlines and 

coarse nervation of the plant remains very satisfactorily, but does not well retain 

the fine nervation. A number of the species, however, are so characteristic that 

there can be little doubt as to their determination.

The collection consists of thirty-five specimens representing about twelve species, 

the most important of which belong clearly to the Laramie group. They are as 

follows:

*Sequoia lorigifolia Lx. Ficus planicostata ? Lx.

Sequoia reichenbachi Heer. *Ficus irregularis ? Lx.

Glyptostrobus enropaeus ? Heer. *Vibnrnuin margiuatum Lx.

Salix eloiigata O. "VVob.. Viburnum sp.

Sa'lix integra Gopp. *Cinnamonum affine Lx.

Salix sp. "Magnolia tenuinervis Lx. 

Ficus lanceolata Heer.

Those marked with an asterisk in the above list are, according to Mr. 

Kuowlton, u Laramie species about which there is little doubt as to

their correct determination." The others are u either fragmentary and 

therefore of doubtful determination, or occurring in formations other 

than the Laramie." Only one species in the list, Sequoia rcichenbachi, 

is known to occur below the Laramie and it has a wide range, being 

found from the Jurassic or Lower Cretaceous to the Tertiary.

If the evidence of these plants were considered alone there could be 

no hesitation in referring the strata containing .them to the Laramie. 

Some of the invertebrates also from No. 7 are very closely related to 

Laramie species if not identical with them, but unfortunately the most 

of them are of types that have a great vertical range and therefore are 

of little use in correlation. Ostrea coalvillensis is probably identical 

with 0. glabra. Corbula subtrigonalis is a Laramie species, but closely 

similar form s occur in the Colorado. Anomiapropatoris also is represented 

in both of these formations by closely similar or identical forms. Hodiola multilinigera is a Colorado species and it has near relatives in the 

Laramie. The form listed as Melania seems to be very close to Melania 

ivyomingensis, a species that ha-s been considered characteristic of the
NORTHERN UTAH. 43

Laramie, though it does occur associated with marine form sin the uppermost Fox hills beds. The Admetopsis is apparently the same species 

that occurs so abundantly with Ostrea solenis'cus, Modiola multilinigeraf, 

etc., near the base of the upper division of the Upper Kauab section. 

The species of Neritina belong tp types that range from the Colorado 

to the Laramie. In fact none of the brackish-water species of these 

lists would be thought out of place if they were found in the Laramie. 

But when it is known that the beds containing them are overlain by 

3,800 feet of marine Cretaceous strata their Laramie age is rendered 

very doubtful. In many respects the facts observed recall the Belly 

River series of the Canadian geologists, but at Coalville the brackishwater conditions seem to have been too limited both in area and duration to be regarded as more than a temporary phase perhaps an estuary in a marine formation.

Twenty feet above the bed from which the plants were obtained and 

in the same exposure a thin layer of sandstone is filled with the remains 

of marine invertebrates mostly in the form of casts. The following 

species have been collected from it:

Cardium curtnm. - Gyrodes.

Cardinal u. sp. Pyropsis.

Mactra arenaria. . Fusus.

Mactra forrnosa? Bai'ulites ovatusf

Tollina isouema? Placeuticeras placenta var.

Donax cuneatal intorcalare.

Barbatia. Scaphites.

Anatina.

The most abundant and best preserved species are Cardium curium 

and Mactra arenaria, neither of which has been found elsewhere than 

in this immediate region or in the strictly equivalent strata of western Wyoming. Of the others the bivalves and the gasteropoda are of 

doubtful value, and the cephalopods apparently belong to the fauna of 

the Montana formation, though the Placenticeras also occurs in the 

Colorado formation.

The more massive sandstones of No. 8 have yielded 

Ostrea soleniscus. Cardiuin.

Ostrea sannionis. Doiiax?

Tollina subalata? Bacnlites ovatns.

Mactra formosa? Placenticeras placenta, var.

Mactra arenaria. intercalare.

Pholadoinya subventricosa.

It has already been shown that marine Cretaceous fossils have been 

found at two other horizons above this, one near the middle of No. 9 

and the other in No. 10, and they all^belong to the fauna represented 

in the last two lists.

After attempting to give clue weight to each "element in this conflicting evidence it seems to me most reasonable to refer the strata containing the "Laramie" plants and the brackish-water invertebrates of
44 COLORADO FORMATION AND. ITS INVERTEBRATE FAUNA, fnuw. 106.

Laramie affinities to the Montana formation. If the true Laramie is 

present it is represented by the strata above No. 10 of the section and 

these have yielded no fossils.

The beds beneath the Coalville section are not exposed in the immediate neighborhood, but near Eockport, on the Weber river, 12 miles 

above Coalville, the continuation of the section down to the Trias 

may be seen. The strata are highly disturbed, dipping northward at 

angles varying from 30° to 80°. There are at least two faults in the 

series, and the great apparent thickness of the section suggests that 

there may be others by which strata are repeated.

The lowest fossiliferous zone of the Coalville section with the characteristic species, such as Barlatia micronema, Mactra utahensis, Moiliola 

multilinigera, and others, is well developed. Beneath (south of) this 

bed there are no good exposures for a distance of 2,200 feet. Then 

come the following strata in descending order:

Feet.

1. Alternating beds of coarse sandstone and shale. The beds of sandstone

vary in thickness from 10 feet to over 100 feet, and their aggregate thickness is somewhat less than that of the shales. A few specimens of Ostrea 

and casts of Cardium and other bivalves were found in the lower porT 

tions. Total apparent thickness ...................................... 2, 500

2. Drab shales with indurated bands in which numerous scales of fishes and

an obscure impression of an Ammonite were collected .................. 215

3. Covered for a distance of ................................................ 700

4. -Reddish and brownish shales alternating with thinner beds of coarse gray

sandstone, changing to brown pebbly conglomerate in the lower 650 feet. 2, 400

5. Reddish shales with thin beds of brown sandstone ....................... 433

6. Dark greenish gray sandstone, someAvhat calcareous, especially toAvard the 

top. A specimen of Trigonid gnadrangularis ? and a few other obscure fossils indicate that this bed is Jurassic ................................... 55

7. Gray and reddish sandy shales, with bands of sandstone .................. 1, 295

8. Yellowish gray shales, becoming calcareous toward the base .............. 935

9. Blue thin bedded limestone and calcareous shales containing Pcntacrinus

astcriscus, Pleuromya subcompressa, and other Jurassic fossils.... ......... 422

10. Reddish brown thin bedded Triassic ? sandstone, exposed ................ 750

The thicknesses given are from measurements made on the assumption that there is no duplication of strata by faulting. The observed 

faults that have been mentioned are not within the limits of the section. If the beds down to and including No. 4 be regarded as Cretaceous, this gives an apparent thickness of over 6,000 feet of Cretaceous 

strata beneath the Coalville section. On East Canyon creek below 

Parley's park the thickness from the base of the conglomerates, like 

those of No. 4, to the top of the fossiliferous sandstone there exposed 

seemed to be a little over 5,000 feet, but that was only an estimate 

based on observed dips and paced distances.

The conglomerates of No. 4 were mapped as Dakota by Mr. Emmons, 

and the two other u Dakota" areas that 1 have visited in this region 

one on East Canyon creek and the other on Chalk creek show the 

same beds. That they are Cretaceous is very probable, but that they
STANTON.] NORTHERN UTAH. ' 45

should be strictly correlated with, the Dakota sandstone east of the 

Eocky mountains seems to me doubtful,

In a previous paper' already cited, I have shown that in western 

Wyoming the brackish water Bear Biver formation, formerly called the 

Bear Biver Laramie, is beneath the Colorado, and that it rests on just 

such a series of shales, sandstones, and conglomerates as is included in 

No. 4 of the Bockport section.; The nearest locality at which Bear Biver 

fossils have been found is the well known one on the Union Pacific 

railroad near the month of Sulphur creek, which, is about 40 miles from 

Bockport. The lowest strata there exposed are the upper part of the 

Jurassic.

The detailed sections as seen in various exposures in the immediate 

neighborhood of Sulphur creek may be thus epitomized in ascending 

order:

root.

1. Reddish brown, and bluish shales and shaly sandstones with a thin calcareous band about the middle containing Selemnitos dcnsus, Trigonia 

quadras f/nlarts, and Plenromya welerensis. Thickness about.......... 500

2. A heavy bed of,brown pebbly conglomerate forming the base of a series 

of alternating coarse sandstones, and variegated shales that was .doubtfully referred to the Dakota. Total thickness ...................... 1, GOO

3. Very fossiliferous dark calcareous shales with a few thin beds of sandstone. Fossils: Pyrgulifera Uumerosa, Corlicula durkeci, Unio veluslits, 

Corliiila pyri/ormis, etc.............................................. 840

4. Blue and brownish fissile shales Avith many scales of fishes, a few fragments of Ammonites and, at a higher horizon, numerous specimens of 

Cardiumpa'ivpcrcutym. jSorne beds of sandstone are probably included. 

Thickness estimated............................................... 1,000-1,500

5. At a higher horizon, the exact position of which could not be determined in the 

local sections on account of faults, a sandstone accompanying a coal bed yielded 

Inoccramus labiatus, Corbula sttbtrigonalis ?, Donax cuncata, Pugnellusfusiformis, Ostrca 

solc-niscns, and other species that permit its correlation with No. 4 of the Coalville 

section. There are also higher beds exposed here, but owing to the complicated 

structure the upper part of the section has not been worked out.

No. 1 is Jurassic, and it is comparable with. Nos. 5 and 6 of the Bockport section.

No. 2 is very much like No. 4 of the Bockport section. The conglomerate at the base is of the same character at both places, though near 

Sulphur creek it reaches a thickness of 150 feet, while at Bockport it is 

broken up into several thinner beds, the thickest of which is about 50 

feet.

No. 3 is the Bear Biver formation Avith its characteristic fossils here 

ranging through only 650 feet of strata, but at other localities farther 

north the fossils were found to range through athickness of at least 2,500 

feet, extending down almost to the conglomerate at the base of No. 2. 

The failure to find Bear Biver fossils at Bockport and in Bast canyon 

may be due to the incomplete exposures of strata there, as the por-

'Am. Jour. Sci., vol. XLIII, 1892, pp. 98-115.
46 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL. 100.

tions of the section in which they were expected were much covered 

with d6bris, but it is quite probable that the fresh and.brackish waters 

in which they flourished did not extend as far south and west as these 

localities. At any rate, the formation has not been found beyond them 

in those directions. Although the Bear Eiver formation as such seemed 

to be absent, nevertheless its position in the Eockport section is plainly 

indicated by the indirect circumstantial evidence of a similar succession of strata and of apparently identical underlying and overlying 

beds to be about that of the covered space No. 3 and the upper part 

of No. 4.

The lower part of the shales overlying the Bear Eiver formation on 

Sulphur creek are in every respect similar to No. 2 of the Eockport 

section. In the earlier paper they were referred to the Colorado formation, and they seem to be faunally connected with it, but their position 

is now seen to be considerably lower than I then suspected, though, 

owing to the doubt' concerning the number of faults in the Eockport 

section, I am still unable to say how many hundred feet they are below 

the base of the Coalville section. The very great thickness of strata 

between the top of the Colorado formation at Coalville and the base of 

the so-called Dakota conglomerates (it can hardly be less than 5,000 or 

6,000 feet) causes me to suspect that the latter are someAvhat older than 

the Dakota sandstone as developed east of the Eocky mountains. After 

making such allowance for differences in the rate of deposition as the 

character of the strata will permit and assuming that sedimentation was 

continuous in both regions, as seems to have been the case, the 1,000 or 

1,200 feet of strata in the one region can hardly be regarded as the complete equivalent of 5,000 or 6,000 feet in the other.

From the foregoing descriptions of local sections it is seen that in 

the larger part of the area the Colorado formation rests with apparent

conforniability on the Dakota sandstone; that in southern Utah its 

fauna ranges down to the local base of the Upper Cretaceous and through 

beds that have usually been correlated with the Dakota, and that in 

southwestern Wyoming it rests on the Bear Eiver formation, with which 

it seems to be conformable. It is also shown that the Colorado formation is overlain by the Montana formation with a distinct marine Cretaceous fauna. With the exception of the two or three instances noted 

no nonconformity has been observed between these two formations.

The accompanying faunal lists show the geographical distribution of 

nearly all the species and their vertical range within the area here discussed, and they also show the reasons for correlating the different 

sections. -

A more general consideration of the fauna as a whole in its relations 

to other Cretaceous faunas in this country and in Europe will now bo 

given briefly.
STANTON.] COMPARISON WITH MONTANA FAUNA. c 47

THE RELATIONS OF THE COLORADO FAUNA TO OTHER CRETACEOUS FAUNAS.

Within the geographic limits arbitrarily assigned to the Colorado 

formation in the early part of this paper there is only one other marine 

Upper Cretaceous fauna that of the Montana formation, which immediately overlies it. The larger part of it was described and illustrated 

by Prof. Meek in his volume on Invertebrate Paleontology, 1 and many 

additional species have been described by Dr. White, Prof. Whitfield, 

and others. A comparison of these two successive faunas shows that 

they are remarkably distinct although, as should be expected, they 

have some'Species in common and others that are very closely related. 

The species that are considered identical nearly all belong to genera 

whose species are seldom sufficiently differentiated to be depended

upon in close geologic correlation. Those that seem to have passed up 

from the Colorado to the Montana formation are not usually found associated with the typical Montana fauna, but the most of them occur 

in that peculiar phase of it that was developed along the western 

shore line.

In .the following list of common and closely related species in the 

two formations the interrogation after a name indicates a doubt as to 

.the identity of closely related forms:

Colorado formation. ' Montana formation.

Ostrea soleniscns. 0. soleniscus..

Ostrea prudeutia. 0. patina.

Anomia propatoris? A. propatoris.

Modiola multilinigera. M. inulfcilimgcra?

luoceramus sirapsoni. I. siinpsoni.

Barbatia niicrcmcina. B. mioronemu?

Nemodon sulcatinus.? N. snlcatinns.

Luciria sulmndata. L. snbundaia.

Veniella morfconi. V. hnmilis.

Aiiatina lineata. A. lineata? 

Corbula subtrigonalia. C. subtrigonnlig.

Lunatia coucinna? L. concinna.

Baculites asper. B. asper? 

Placenticeras placenta. P. placenta.

In addition to these the species of Neritina, Eulimella, Cliemnitzla, 

and Aclmetopsis, occurring in the Colorado formation in Utah, belong 

to types that are also found in the higher beds of the same region.

If we now compare the Colorado fauna with the fauna of the Eipley 

formation of the southern United States, which is believed to be theequivalent of the Montana formation, some additional resemblances are 

seen. For example, the genera Triyonarca, Gyrodes, Rostellites, and 

Pugnellus are present in both, and the first two are represented by 

similar species, but none of the forms that can be considered characteristic of the Colorado fauna are known in any of the more recent faunas.

Before comparing our fauna with others believed to have been con-

>TJ. S. Geol. Surv. Terr., Vol. ix, Pis. 10-39.
48 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL. 106.

temporaneons, it may be well to enumerate some of its most characteristic forms. Those given in the following list are not known to range 

into strata above the Colorado formation and all are sufficiently abundant 

and widespread to be of use in correlation. Many others are equally 

as characteristic, but have been found at only one or two localities:

Ostrea lugubris. Cardium pauperculuin.

Exogyr.a columbella. Liopistlia (Psiloniya) m.eeki. 

Gryphaea newberryi. ' Liopistlia (Psilquiya) coucentrica.

Avicula gastrodes. Turritella whitoi.

Gervillia propletira. Glaucoma coalvillensis.

Inoceramus labiatua. Pugnellus fueilbrmis.

I. diinidius. Baculites gracilis.

I. fragilis. Buchiceras swallovi.

I. umbonatus. Scapbites warreni.

I. exogyroides, Prionocyclus.

I. deformis. Prionotropis.

I. undabundus. Mortoiiiceras.

None of the keeled Ammonites included in the last three genera 

above named have been found above the limits of the Colorado formation and its equivalents ia America.

The fauna is also negatively characterized by the absence of "many 

types that form prominent features of the Montana fauna. Among such 

may be mentioned the genera Heteroceras, Ptychoceras, and Anisomyon; 

the large species of Baculites, such as B. ovatus,- grandis, and compressus, Scaphites conradi and Scapliites nodosus, and the broad compressed forms of Inoceramus, like I. sagensis and I. vanuxemi.

The Eagle ford shales and the Austin limestone of Texas have already 

been alluded to as the equivalents of the Fort Benton and Mobrara, 

respectively. This correlation was made on a good paleontological

basis by Shumard, Meek, White, and others, and it has never been questioned. The fauna! lists published by Mr. E. T. Hill 1 contain the following species that occur in the Colorado formation or are represented 

by closely related forms:

From the Eagle Ford shales.

Ostrea congesta. Buchiceras swallovi.

O. bellaplicata [lugubris.] Mortouiceras shoshoncuse.

Exogyra columbella. Prionotropis woolgarL

Inoceramus exogyroides. Aucyloceras? annulatus.

I. involutus [umboiaatus.] Ammonites graysoiicnsis. 3

I.labiatus. Ammonites rueekianus.3

From the Austin limestone.

Ostrea congesta. I. labiatus.

Exogyra colnmbella. Trigonarca sp.

E. Itevinscula. 1 Nautilus elegans.

E.ponderosa. Mortoiiiceras vespertinnm

Inoceramus exogyroides. (=Anirn. texanus).

I. involutus. Mortoniceras shoshoncnso.

I. umbonatus. Baculites asper.

1 Geol. Sur. Tex. Bull. No. 4, Check List, Grot. Invert. Foss. of Tox., pp. 51-53. 

* These probably are species of Prionotropis.
STANTON.] OTHER AMERICAN CRETACEOUS FAUNAS. 49

Associated with these is a large number of other species that have 

not been recognized ILL our area. The fauna of the Austin limestone 

seems to be somewhat more closely related to that of the overlying 

beds than is the Colorado fauna to the Montana.

Some of the species doubtfully assigned to the Eagle Ford shales are 

also listed as occurring in the Denisonbeds at the top of the Comanche 

series, but this is probably an error, since the species in question are 

entirely Upper Cretaceous forms and several of them occur in the Colorado formation.

Beneath the Eagle Ford shales the Timber Creek formation (Lower 

Cross Timber sands of Hill) contains an unstudied marine fauna that will 

probably prove to be closely related to the Colorado fauna, especially to 

that part of it that occurs in the lower portion of the formation in Utah.1

The Upper Cretaceous faunas of Mexico have not been studied, but

theoccurrence.of Inoceramus labiatus at several localities in Chihuahua 

indicates the presence of the Colorado fauna there, though Dr. White 

has suggested that the Upper Cretaceous strata of that region are not 

divisible into distinct formations.

The Colorado fauna has not been recognized in any of the states east 

of the Mississippi. If it is represented at all in the Alabama-Mississippi region it should be sought in the Tombigbee sands and the Eutaw 

formation and perhaps the lower part of the " Eotten Limestone," none 

of which has been much studied paleontologically.

On the Pacific coast of the United States the Cretaceous faunas generally are very different from those occurring east of the mountains, 

having few if any species in common. None of the characteristic Colorado species has been found there, and it has not yet been determined 

whether any of the Cretaceous formations of California, Oregon, and 

Washington are strictly the equivalents of the Colorado formation. Farther north, however, in the upper shales and sandstones of the Queen 

Charlotte islands Inoceramus labiatus is reported2 to occur, and this may 

be considered the most characteristic species of the Colorado fauna.

In the Eocky mountain region of British America, Dr. Gr. M. Dawson 3 obtained the following species that clearly belong to our fauna:

Ostrea congesta. Pholadomya papyracoa. . 

Inoceramus exogyroides. Scaphites warreni. 

I. undabnndus. . S. vermiformis ? 

I. labiatus.

From the " Mobrara-Bentou formation" in the Duck and Biding 

mountain district of Manitoba, Mr. Whiteaves 4 records the following 

species:

Serpula semicoalita. Inoceramus labiatus.

Lingula subspatulata? Modiola tenuisculpta.

Ostrea congesta. Bolenmitella mauitobensis.

Anomia obliqua. Loricula canadensis.

1 Vide White, C. A., Bull. 82, U. S. Geol. Sur., p. 121. - 2 "WLiteaves, J. F.: Mesozoic fossils, Vol. 1, p. 103. 

* WMteaves, Gout, to Can. Paloeont, Vol. I, pp. 83-80.- * Ibid., pp. 185-191..

BulL 106 1
50 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL.IOG.

In several of their joint papers Messrs. Meek and Hayden suggested 

the correlation of the "lower series" of their section with the Lower or 

Gray Chalk of the English geologists. In 1861 they stated their views1 

thus:

Having now considered, in the order of their succession, the several rocks embraced in the lower series of the Nebraska cretaceous deposits * * * it will be 

interesting to see how nearly their synchronism with known horizons in the Cretaceous system of the old world can be traced out. With this view we have carefully 

compared with European forms all the fossils in the several Nebraska collections 

from the rocks, including those most recently obtained, to which the new species 

described in this paper belong. These comparisons have satisfied us that the formations under consideration, that is, the Niobrara division, Fort Benton group, and the 

Dakota group represent together the Lower or Gray Chalk, and probably the Upper 

Greensand of British geologists (Turonien and Cenomanien of d'Orbigny).

Seven identical or closely related species are listed as occurring in 

both the American and the foreign formations. In Prof. Meek's latest 

work, so frequently cited, this correlation is again maintained and based 

on the same evidence. At that time less than twenty-five species were 

known to belong to the Colorado fauna.

A comparison of the much greater number of the species now known 

with those of the European Turonian in the light of more definite statements concerning the vertical range of European species as given by 

Barrois,2 Schliiter,3 Zittel,4 and others furnishes additional evidence 

mainly in the same direction. The following comparative lists contain 

the most prominent examples of identity or^ close similarity:

From the Colorado formation. From the Cenomanian. 

Nautilus elegans. Nautilus elegans. 

Scaphites warreni. ) 

Scaphites larvBformiB. { Scaphites sequalis.

	From the Turonian.

Exogyra suborbiculata. Exogyra suborbiculata.

Anomia subquadrata. Anomia truncata.

Avicula gastrodes. Avicula caudigera.

Inoceramus labiatus. Inoceramus labiatus.

Inoceramus deformis. Inoceramus cuvieri.

Amauropsis bulbiformis. Amauropsis bulbiformis.

Rostellites dalli. Rostellites elongata.

Baculites gracilis. Baculites bohemicus.

Prionotropis woolgari. 5 Prionotropis carolinus.

I Prionotropis woolgari.

Prionotropis loevianus. Ammonites nodosoides.

Prionocyclus wyomingensis. Ammonites germari.

In Germany Dr. C. Schliiter has described, under the name "Einscher Mergel," a formation overlying the Turouian which he regards as 

intermediate between that formation and the Senonian, though it has

> Proc. Acad. Nat. Sci. Phila., 1861, p. 423.

2 Barroia, C.: Terrain Cretac6 de 1'Angleterre, Lille, 1876.

3 Schliiter, C.: Cephalopodcn der obereu deutschen Kreide, Palceontographica, Vol. xxiv, 1876, pp. 

87-134.

4 Zittel, K. von.: Hanclbuch der Palajontolo^ie.
STAOTON.] COMPARISON WITH EUROPEAN FAUNA. 51

usually been placed at the base of the Senonian. It is especially characterized by the keeled Ammonites, such as those we have referred to 

Mortoniceras and Prioncyclus and by certain forms of Inoceramus. 

Several species are represented by identical or closely related American 

forms, as follows:-

From the Colorado formation. From the Emscher Mergel.

Inoceramus umbonatus. ) Represented by Inoceramus involutus.

Inoceramus exogyroides. )

Inoceramus deformis. Inoceramus cuvieri.

Baculites asper. Baculites incurvatus.

Mortoniceras shoshonense. Mortoniceras vespertinum.

On account of the occurrence of these forms and. a few others in 

Texas, Dr. Schliiter 1 has considered the beds (Austin limestone) containing them the equivalent of the Emscher Mergel.

It is interesting to compare these facts with the evidence furnished 

by vertebrate fossils from, the Colorado formation. I can not do this 

better than by quoting the statements of Prof. E. D. Cope:2

The fauna of the deep sea epoch, the Niobrara, is the best known. Here the remains 

of Pythonomorpha constitutes the prevailing characteristic, while Elasmosaiirus and 

Polycotylus, with but few species, represent the numerous Sauropterigia of Europe. 

Crocodiles were apparently wanting, while turtles and a peculiar group of Pterosauria were only moderately abundant. The fish fauna was very rich and varied. 

Here the Saurodontidce, like the molluscous family of the Rudistce, appeared and as 

soon disappeared, accompanied by the peculiar form Erisicthe and the family of 

Stratodontidce. The genera of Mount Lebanon, Leptobrachelus and Spaniodon 

occur in this bed in Dakota, but the closest parallelism is exhibited with the Lower 

Chalk or Turonian of western Europe. The general facies of the reptilian fauna 

is that of the Lower Chalk, and there is little doubt that several genera are identical in the two continents, e. g., Elasmosaums. The apparent peculiarity of the 

Chalk in America is the abundance (four genera) of Pythonomorpha, with numerous 

species, while but two genera have yet been found in Europe, and the presence of 

birds with biconcave vertebrae and teeth. This interesting type, which was first discovered by Seeley in the genus named by him Enaliornis, and afterwards found by 

Marsh to have teeth, has been found at a lower horizon in England, the Upper Greensand. But in England, France, and Westphalia occur the genera of fishes above 

mentioned, as, Porthenus, Ichthyoclectes, Saurodon, Saurocephalus, Urisicthe, JEmpo, 

Pachyrhizodus, Enchodus, Leptotrachelus, etc. This close relationship of the horizons permits an identification, and it is the first instance that appears to me susceptible of satisfactory demonstration.

Again, on page 42 in "Eesume of Comparisons," he says: "Exact 

identification of restricted divisions may be made in a few instances 

only, such as the -Turonian and the Niobrara."

Sufficient evidence has been given to show that the invertebrate fauna 

of the Colorado formation can not be divided into well defined subfaunas or zones corresponding to those that have been recognized in 

Europe. It is true that certain types seem to be confined to the upper 

part and others to the lower part of the formation, but some of the most

1 Op. cit., p. 113, and Naturh. Ver. pr. Rheinl. Sitzungsb. Jahrg. 44, 1887, p. 47.

2 Cope, E. D.: Cretaceous Vertebrata. TJ. S. Geol. Sur. Terr., vol. in, pp. 27,28,
52 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [uuLL.106.

characteristic species, such as Inoceramus labiatus, range from the bottom to the top. The fauna as a whole maybe regarded as the approximate taxonomic equivalent of the Turonian, though it is not probable 

that either the beginning or the end of the epoch was contemporaneous 

on the two continents. The few species that are compared with Cenomanian forms are not important. One of them, Nautilus elegans, occurs 

in the upper part of the Colorado formation (at least in Texas), while 

the Scaphites are associated with Inoceramus laliatus, Prionotropis 

ivoolgari, and Prionocyclus wyomingensis in the Fort Benton shales.

The indefinite ness of thecorrelationoftheupperpartoftheformation 

the Mobrara and its equivalent, the Austin limestone is shown by the 

facts above given, the vertebrates belonging to the Turonian types, 

while the mollusks may be compared in part with Emscher or lowest 

Senonian forms. As usual when an attempt is made to identify formations in such widely separated regions, the identification is most certain 

when only one class of facts is examined, and becomes doubtful when 

the facts are more numerous aud are gathered from more varied sources.

DESCRIPTION OF SPECIES.

ECHINODERMATA. 

CRINOIDEA.

UINTACRINID^E.

Genus HINTACRINUS Grinnell. 

UINTACRINUS SOOIALIS Grinnell.

Uintacrinus socialis Grinnell, 1876, Am. Jour. Sci., vol. xn, p. 81; Meek, 1876, Bull. 

U. S. Gcol. Sur. Terr., vol. n, p. 375; Clark, 1893, Bull. U. S. Geol. Sur., No. 97, p. 21, 

PI. 1, Figs, lo-c, and PI. 2, Figs. la-e.

This species and the following one having been recently described 

and illustrated in a publication of the U. S. Geological Survey, are 

listed here simply with references for the sake of completeness.

ECHINOIDEA.

CASSIDULIDyE.

Genus CASSIDULUS Lamarck.

CASSIDULTJS STANTONI Clark, :,

Cassidulus stantoni Clark, 1891, Johns Hopkins University Circulars, No. 87, p. 76; 

1892, Bull. U. S. Geol. Survey, No. 97, p. 73, PI. 35, Figs. 2o-d,
STANTON.] SERPULID.E. 53

VERMES.

SERPULID^E.

Genus SERPULA Linnaeus.

SERPULA INTRICA White.

PI. i, Fig. 1.

Serpula intrica Wliite, 1876, U. S. Geog. and Geol. Stir. West lOOfch Meridian, vol. rv,

p. 205, PI. 15, Fig. 5a. 

Compare Serpula .gordialis (Schloth.) Geinitz, Palseontographica, vol. xx; pt. 1, p.

282, PI. 63, Figs. 2, a.

" Tubes small, slender, cylindrical, smooth, very long and very tortuous, not perceptibly increasing in size, so far as our examples show, 

but neither the distal nor proximal extremity of the tube has been found 

unbroken.

" Diameter of the tube, a little more than 1 millimeter.

"This species is remarkable for the great length and uniform size of 

the tubes and for the intricacy of their Contortions.

"Position and locality. Strata of the Cretaceous period; southeast 

of Paria, Utah."

SEEPULA f TENUICARINATA Meek and Hayden. 

PI. I, Fig. 2.

Serpula ? tenuicannatm Meek and Hayden, 1857, Proc. Acad. Nat. Sci. Phila., p. 134; 

Meek, 1876, U. S. Geol. Snr. Terr., vol. ix, p. 507. PI. 6, Fig. 1.

"Tubes growing in groups, or rarely single, nearly cylindrical, increasing very gradually in size, irregularly curved, but apparently never 

spirally coiled, attached by the under side throughout most of the 

entire length; upper side having a distinct, rather sharply elevated, 

flexuoiis, longitudinal carina; surface smooth.

"Length unknown; average transverse diameter, 0-14 inch.

"Not having seen entire specimens of this species, it js with some 

doubt that it has been referred to the genus Serpula. It seems never 

to have internal septa as in Vermetus. It was originally placed provisionally in the genus Serpula and is here, in the same way, retained 

in that group.

"Locality and position. Mouth, of Vermilion river, [South] Dakota, 

on .the Missouri, in*the Fort Beuton group of the upper Missouri Cretaceous series."
54 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL .106.

MOLLUSCA.

PELECYPODA.

OSTREIDAE. 

Genus OSTEEA Linnaeus.

OSTREA PRUDENTIA White.

PI. I, Figs. 3 and 4.

Oatrea prudentia White, 1876, U. S. Geol. Stir. West 100th Meridian, vol. iv., p. 171, 

pi. 14, Figs. 2a-d-, 1884, 4th Ann. Rept. U. S. Geol. Sur. p. 299, PI. 40, Figs. 5 

and 6.

Compare Ostrea patina Meek and Hayden, 1856, Proc. Acad. Nat. Sci. Phila., p. 277; 

Meek, 1876, U. S. Geol. Sur. Terr., vol. ix, p. 16, plates 10 and 11.

Original description:

" Shell neat and symmetrical for a species of this genus, suboval or 

subcircular in outline when adult, subcircular when young, moderately 

capacious; bea.ks small, usually distinct, and approaching so near to 

each other when the valves are together as to leave only a narrow 

space between the areas. Lower valve moderately deep; area short 

and broad; ligamental groove short, broad, and distinct, bounded at 

each side by a rounded ridge; beak extending very slightly beyond 

that of the other valve; scar of attachment sometimes occupying onequarter of the outer surface, sometimes extremely small, and * sometimes apparently absent. Upper valve usually flat or a little concave 

transversely; but a little convex longitudinally in adult shells; area a 

very little shorter than that of the other valve, moderately convex or 

nearly flat.

" Surface of both valves marked by distinct lines and laminae oi 

growth, but this species is rather less laminated and roughened than 

is usual in the genus Ostrea. Somewhat numerous, corrugated, but 

rather indistinct, radiating costas are usually to be seen on the ventral 

valve of young examples, yet these corrugations seldom or never extend 

to the front half of old shells.

"Length, 6 cm.; breadth, 5 C7n. . .

"This species is somewhat remarkable for its neatness of form and 

freedom from the crude extravagances which species of this genus often 

exhibit.

"Position and locality. Strata of the Cretaceous period, east of Impracticable ridge, Utah."

This species so closely resembles some specimens of Ostrea patina 

M. & H., from the Montana formation, that I have been inclined to treat 

it as a synonym of that species. In the geology of tjie Uinta mountains 

Dr. White gives it in the list of species belonging to the Henry's Fork 

group, which has since been correlated with the Dakota, but a number
STANTON.] OSTREID^E. 55

of the species in that list have been found to occur in the Colorado formation, and I have included all .of them in its fauna, though some ot 

them may have been found at a lower horizon than is usually regarded 

as the base of that formation.

' OSTREA ANOMIOIDES Meek. 

PI. I, Figs. 5 and 6.

Osirea 'anomioides Meek,. 1873, Ann. Eept. U. S. Geol. Sur. Terr, for 1872, p. 488; 

White, 1880, idem for 1878, p. 10, PI. 11, Figs. 4a, &; 1884, 4th Ann. Kept. U. S. 

Geol. Sur., p. 291, PI. 39, Figs. 4 and 5.

Original description:

" Shell rather small, very thin, depressed plano-convex, and without 

any visible scar of attachment, varying from ovate to circular; rounded 

or sometimes a little straightened on the hinge margin; beaks scarcely 

projecting beyond the outline of the cardinal margin. Lower valve 

very shallow; cartilage pit unusually small, shallow^ and short. Upper valve almost perfectly flat; cartilage attachment even shorter than 

that of the other valve, and slightly convex on its inner margin. Muscular scars unknown; surface of both valves with small regular concentric wrinkles most distinctly marked on the central region.

" Greatest diameter of one of the largest.oval specimens, 1.70 inches; 

breadth, 1.40 inches; convexity, 0.23 inch.

" This species is remarkable for the thinness of the shell, the slight 

concavity of the under valve, and the'flatness of the upper, as well as 

for its rounded or slightly straightened cardinal margin, and the absence 

of any scar of attachment, or of any traces of muscular impressions 

within. These external characters, and the regular small concentric 

wrinkles, give the exterior of the lower valve of circular specimens 

somewhat the appearance of a I/ucina or Dosinia; while in other individuals it looks more like an Anomia or Plaouna.

"Locality and position. Missouri river, below Grallatin city, Montana. 

Cretaceous."

OSTREA CONGESTA Conrad. 

PI. n, Figs. 2, 3, and 4.

.Ostrea congesta Conrad, 1843, Nicollet's Rept. of Explorations in the Northwest, p. 

167; Hall, 1856, Pacific R. R. Reports, vol. in, p. 100, PI. 1, Fig. 11; Meek, 1876, 

U. S. Geol. Sur., vol. ix, p. 13, PI. 9, Figs, la-/; White, 1884, 4th Ann. Rept. U. 

S. Geol. Sur., p. 294, PL 39, Figs. 11,12,13.

Prof. Meek's description is as follows:

"' Shell elongated; upper valve flat; lower valve ventricose, irregular; umbo truncated by a mark of adhesion.' (Conrad.)

"tfhis is a small, thin shell, the individuals of which are often 

crowded together in considerable numbers, so as to assume quite irregular forms. In cases where the individuals had room to grow without
56 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL.JOO.

interruption, the young shell is usually found to be of an ovate form, 

and attached by the whole under surface of the lower valve, the beak 

of which is pointed, provided with a small triangular area, and usually 

turned a little to the left. In this form they continue to grow to 

lengths varying from 0.25 to 1 inch, when, the margins are abruptly 

deflected upward at right angles to the flat attached base, and produced in this direction often for as much as an inch or more; the greatest extension being on the lateral margins and at the extremity opposite the beaks. When seen at this stage of their growth, separated 

from the body to which they were originally attached, and lying partly 

embedded in the matrix, with the beak side down, they look like short 

cylindrical tubes, with one end abruptly truncated and closed by the 

flat surface of attachment; so that what was originally the whole 

under surface of the valve now appears like the truncated umbo.

" The other valve is quite flat, or sometimes a little concave, and 

always retains the form possessed by the attached valve at the time its 

margins became deflected upward, after which it seems to have increased very little in size. Its umbo is usually a little less pointed 

than that of the other valve, and provided with a shorter area, on each 

side of which its margins are sometimes slightly crenulated.

" The muscular impressions of both valves are obscure, and the surface is nearly smooth, or only marked by fine, indistinct lines of growth.

"Locality and position. At numerous places along the Missouri 

between the Big Sioux and the Great Bend; also on the Little Blue 

river, near the Kansas and Nebraska line, and near the Black hills, on 

Cheyenne river, as well as on the North Platte; in the Niobrara. group, 

or formation No. 3, where it is usually found attached to fragments of 

a large Inoceramus. It likewise occurs at several localities in New 

Mexico and Colorado, probably in the same position."

OSTREA SOLENISOUS Meek. 

PI. u, Fig. 1; PI. m, Figs. 1 and 2.

Ostrea soleniscus Meek, 1871, Proc. Am. Philos. Soc., voJ. xi, p. 430; 1873, Ann. Rept. 

U. S. Geol. Sur. Terr, for 1872, p. 487; White, 1880, idem for 1878, p. 9, PI. 11, 

Figs. 2a, 6; 1884, 4th Ann. Rept. U. S. Geol. Sur., p. 300, PI. 42, Fig. 1.

Ostrea cortex White, 1876, U. S. Geog. and Geol. Sur. West 100th Meridian, vol. iv, 

p. 170, PI. 15, Fig. 2a-c.

Not Ostrea cortex Conrad, 1857, U. S. and Mex. Bound. Sur., vol. i, p. 157, PI. 11, Fig.

" Shell attaining a large size, becoming rather thick in adult examples, generally straight, greatly elongated, and comparatively very 

narrow, with parallel lateral margins. Lower valve with moderate 

internal concavity, and having the appearance of a little gutter or 

elongated trough; beak usually nearly straight, rather obtusely pointed, 

and more or less distorted by the scar of attachment; ligament area of 

moderate size, strongly striated transversely, and provided with a large,
6TANTON.] OSTREID^E. 57

deep longitudinal furrow; surface apparently only with moderately 

distinct marks of growth. Upper valve almost nearly flat externally, 

but nearly as concave as the other within; beak usually a little truncated; ligament area marked with strong transverse striae, and having 

its mesial ridge very prominent, and occupying as much as one-third 

its breadth; surface as in the other valve, or perhaps a little smoother.

"Length of adult examples about 18 inches; breadth of same about 

2-50 to 3 inches.

"Although not a very uncommon species, I have seen no entire specimens of this remarkable shell. It will be readily known by its usually 

narrow, elongated, and generally straight form. The shell is usually 

found broken into several pieces, but casts of the internal cavity are 

not unfrequently met with entire. One of these before me is nearly 1 

foot in length and only 2 inches in breadth. It often bad a curious habit 

of groAving in groups of three shells, attached to each other by the 

backs of their beaks. I have seen large numbers of them closely 

arranged, or nearly in contact with each other, at Ooalville, all with 

their beaks downward, or at right angles to the planes of the sandstone 

strata. When found where it grows isolated, the shell is sometimes 

arched to one side.

" Locality and position. This species ranges through nearly the whole 

thickness of the Cretaceous sandstones near Coalville, Utah, and is 

also found in the Cretaceous coal-bearing sandstones at Bear River city, 

Wyoming, as well as in a sandstone ridge of same age on Union Pacific 

railroad, a few miles east of the latter locality."

The above is Prof. Meek's revised description of this species, which, 

as hejlntiinates, ranges from beds containing an undoubted Colorado 

fauna far up into those that probably belong to the Montana.

Associated with the very slender forms there are other shorter ones 

broadly ovate in outline that apparently belong to the same species. 

The specimens from southern Utah that were referred to Ostrea cortex 

are of this character. The beaks are usually more or less exogyrate in 

form, this feature being most marked on the upper valve of the broader 

specimens. The same species occurs in the Lower Cross Timber sands 

stone of Denton county, Tex.

OSTREA MALACHITENSIS n. sp. 

PI. n, Figs. 5, 6, 7, and 8.

Shell rather small, irregularly subtriangular in outline; cardinal 

nargin long and nearly straight, more or less distinctly auriculate in 

front cf the beaks, which are small and inconspicuous; lower valve 

moderately convex, with the greatest convexity along an oblique line 

from the beak to the middle of the rwstero-basal margin, which is there 

broadly emarginate, thus giving the shell a saddle-shaped or bilobate 

form. The outline of the shell, exclusive of this broad lobe and the
58 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BOLL.106.

small triangular anterior alation, is oblong oval. Upper valve nearly 

flat or slightly concave, excepting on the posterior margin, where there 

is a broad downward flexure corresponding to the einargination and 

the convexity of the lower valve. Surface of both valves marked only 

by lines of growth and a few concentric laminae.

The largest examples measure 45mm from beak to base, and about the 

same in the greatest length at right angles to that line.

The numerous examples from several localities show less variation 

in form than is usual in species of Ostrea. Its outline suggests 0. malleiformis Gabb from the Chico group of California, but the differences 

seem to be sufficiently great and constant to warrant their separation.

Locality and position. In the Pugnellus sandstone near Malachite 

post-office, Poison canyon, and other localities in Huerfano park, Colorado, and at about the same horizon 20 miles above Pueblo.

OSTREA LUGKJBRIS Conrad. 

PI. iv, Figs. 1-10.

Oslrea lugulris Conrad, 1857, U. S. and Mex. Boundary Rept., vol. i, p. 156, PI. 10, 

Figs. 5a, I; Meek, 1876, Macomb's Expl. Expecl. from Santa F6 to Junct. of Grand 

and Green rivers, p. 123, PI. 1, Figs, la-d; White, 1884, 4th Ann. Rept. U. S. Gcol. 

Sur., p. 297, PI. 51, Fig. 3.

Ostrea bcllaplicata Slmmard, 1860, Trans. St. Louis Acad. Sci.; voL i, p. 608; White, 

1879, Ann. Rept, U. S. Geol. Sur. Terr, for 1877, p. 276, PI. 4, Figs. 3ft, &, and PI. 8, 

Figs. 2a, &; White, 1884, 4th Ann. Rept. U. S. Geol. Sur., p. 292, PL 78, Figs. 1,2,3.

Oslrea ( Alectryonia) llacldi White, 1880, Proc. U. S. National Museum, vol. ir, p. 293, 

PI. 4, Figs. 1,2; Ann. Rept. U. S. Geol. Sur. Terr, for 1878, p. 11, PI. 14, Figs, la, I, 

PI, 17, Fig. 4; 4th Ann. Rept. U. S. Geol. Sur., p. 292, PI. 45, Fig. 1, and PI. 46, Fig. 2.

Shell varying in size from small to medium,- outline usually broad, 

subovate, but in small specimens often nearly circular and in larger 

ones occasionally subtriangular; lower valve moderately convex, the 

greatest convexity being along the median line, which is often, subangular in large shells; beak usually small and inconspicuous, but sometimes more.prominent and curved laterally, often obscured by the scar 

of attachment, which is usually present and is proportionately very large 

in the dwarf variety represented by Conrad's type. Surface marked by 

from twelve to eighteen strong plications, that radiate from the beak or 

the scar of attachment, and by strong concentric lines, and sometimes by 

imbrications of growth. The plications are usually simple, but occasionally they bifurcate. Upper valve nearly flat or sometimes slightly 

concave, with an outline similar to that of the other valve, excepting 

that it is somewhat more narrow along the hinge line. Its surface is 

smooth for some distance around the beak and the plications toward 

the margin are not as strongly developed as on the lower valve, which 

it resembles in other respects. The muscular scars are reniform and 

subcentral; ligamental area varying greatly in size and form, but never 

very large.
RTANTON.] OSTREID2E. 59

Conrad's type (lower valve) measures. 17 mm from beak to base, 15mm 

in breadtli, and 5 mm in convexity, while the corresponding measurements of Ostrea blaclcii, which is the largest variety of the species, are 

68, 62, and 32mm , respectively.

The extreme varieties of the three forms included in the above 

description differ greatly from each other, and when the intermediate 

forms and the facts concerning their distribution were unknown it was 

natural that they should be regarded as distinct species. Conrad's 

types were small specimens from " east of Eed river (Canadian), New 

Mexico, Santa F6 road," where they occur-in a band of brown calcareous sandstone containing Prionocyclus macombi, sharks' teeth, etc. 

The same dwarf form is found in a similar rock in New Mexico and 

southern and southwestern Colorado. In Huerfauo park and adjacent 

regions of Colorado the position of this brown band, which is from, two 

to four feet thick, is at the base of the Niobrara limestone, and the paleontological evidence shows that it is on about the same horizon at the 

other localities. In Huerfano park the Pugnellus sandstone, which 

immediately underlies this brown band, contains great numbers of a 

larger Ostrea that is absolutely identical in form with some of the Texan 

specimens of Ostrea bellaplicata, but associated with them are smaller 

individuals with larger scars of attachment showing every gradation 

from the bellaplicata to the lugubris form. At Eattlesnake butte, 

Colorado, 0. lugubris was found in the brown band, while the shales 

beneath yielded fragments showing all the characters of the large 0. 

blackii. The collections from Texas show the forms intermediate 

between 0. blacMi and 0". bellaplicata, both of which came from the 

Eagle Ford shales, the equivalent of the beds from which the Colorado 

and New Mexican specimens were obtained. From the above facts it 

seems to me evident that Conrad's type specimens were representatives 

of a variety that was dwarfed by unfavorable conditions, while the 

same species under more favorable circumstances reach the large size 

of 0. bellaplicata and blackii. The examples selected for illustration 

represent most of the varieties excepting the largest ones, figures of 

which may be found in the Fourth Annual Eeport U. S. Geological 

Survey.

OSTREA UNIFORMIS Meek.

PI. in, Figs. 3 and 4.

Oslrea (Gryphceaf) uniformis Meek, 1876, Macomb's Expl. Exped. from Santa F6 to 

Junct. Grand and Green rivers, p. 124, PI. 1, Figs. 2a, 1>, c; White, 1884, 4th 

Ann. Eept. U. S. Geol. Sur., p. 302, PI. 48, Figs. 6 and 7.

Original description:

" Shell small, rather thin, trigonal-ovate or subcircular in form, not 

oblique; under valve rather deep, subcarinate-along the middle, and 

arched beneath from the beak to the opposite margin; beak curved 

upward, but truncated by the area so as to rise little above the margins;
60 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL.IOC.

area small; margins on each side of the area sometimes faintly marked by 

fine crenulations along the groove for the reception of the edge of the 

upper valve; surface marked by about three or four rather regular plications on each side of the larger mesial fold or carina; lines of growth 

obscure; muscular scar transversely oval, moderately distinct; upper 

valve unknown.

" Length from the beak to the opposite extremity, 1.16 inches; antero: - 

posterior diameter, about 1 inch; convexity or depth of the under valve, . O.C5 inch.

" This is a very peculiar- shell, and can not be confounded with any 

other species with which I am. acquainted. Its large, prominent, mesial fold, extending from near the beak of the under valve to the 

opposite extremity, with three or four smaller plications on each side, 

give it much the appearance of some of the plicated brachiopoda when 

viewed on the under side. The folds, or plications, vary somewhat on 

different specimens; but usually they are remarkably uniform for a 

species of this genus, and impart to the free margin opposite the beak 

a zigzag character, very similar to the front of some species ofSpirifer. 

No specimens of the upper valve were obtained; but it will probably be 

found to have a large mesial sinus corresponding to the elevation of the 

other valve, and must possess a projection, curving down at the middle 

of the free margin opposite the beaks, to fill the deep notch in the margin of the other valve.

"Thinking this species might be identical with one or the other 

of two peculiar oysters described by Dr. Shumard, from the Cretaceous 

rocks of Texas, under the names 0. bellaplicata and 0. quadriplicata, I 

sent him sketches of our shell, and he wrote that it is most nearly like 

his 0. bellaplicata, though he thinks clearly distinct. The 0. bellaplicata attains a much larger size, some of the specimens being as much as

3 inches in indiameter, while its hinge-line is proportionally much 

longer, and its surface distinctly ornamented with concentric markings." 

Locality and position. Near the base of the Colorado shales at Pagosa 

springs, Colorado, where it is associated with Ostrea lugulris, Inoceramus labiatus (=1. problematicus), and I.fragilis.

Genus GRYPEUEA Lamarck.

GrRYPELEA NEWBEREYI n. Sp.

PI. v, Figs. 1-5.

Grypliaia pitcJteri White, 1876, U. S. Geog. and Geol. Sur. west 100th meridian, vol.

iv, p. 171, PL 17, Figs. la-f. 

Gryphwa pitch(ri Newberry and Meek, 1876, in Macomb's Expl. Exped. from Santa Fd

to Junct. of Grand and Green rivers. 

Not Gryphcea intcheri Morton, 1834, Synopsis Org. Rem. Cret. Group, p. 55, PI. 15,

Fig. 9.

The following is a copy of Dr. White's description and comments: 

" Shell reaching a moderately large size, very variable in shape, gen-
STANTON.] OSTKEID^E. 61

erally having an irregularly subovate marginal outline, often much 

longer than broad, but sometimes shorter than broad. Larger valve 

capacious, scaphoid, arcuate, more or less distinctly lobed, the posterior lobe occasionally somewhat wing-like; test rather thick; umbo 

large, prominent, and incurved, or flattened and short; scar of attachment small or wanting; surface sometimes distinctly lamellose, but 

generally somewhat smooth, although marked by concentric lines of 

growth.

" Upper valve nearly flat, moderately thick in the umbonal region; 

hinge line well denned, straight; area distinct; ligamental groove 

small; inner surface smooth, more or less distinctly crenulated at the 

lateral edges; outer surface marked by numerous concentric, imbricating lines of growth, and sometimes also by faint, impressed radiating 

stride.

"The collections contain numerous examples of this widely-known 

species, none of which, however, are of so large a size as are some of 

those figured by Eoemer, Conrad, and others. In selecting examples 

for illustration I have chosen representatives of two extremes of form 

from among others of all intermediate gradations. Mr. Conrad states 

(loc. cit.) that there are two distinct varietal types of this species, one 

of which resembles G. vesicularis Lamarck, and which was the typical 

form described and figured by Dr. Morton; and the other he designates 

as var. navia. The collections under examination, however, although 

they contain representatives of the two forms referred to by Mr. Conrad, seem to indicate no constancy of separate varietal character, 

either of those forms or any others.

" The largest specimens in the collections have a length of only about 

37 millimeters from the umbo to the basal margin, which is considerably less than that of "some examples reported by other authors."

It is with much hesitation that I propose a new name for this form, 

because as a rule species of the Ostreidse are difficult to define, and 

because I do not wish to add to the confusion that has long prevailed 

concerning Gryphcea pitclieri.1 The latter species is very abundant in, 

and has been regarded as characteristic of, the Comanche series, or 

Lower Cretaceous, of Texas and adjacent regions.

The form now under consideration occurs in great numbers in the 

lower part of the Upper Cretaceous shales in southeastern Utah and 

adjacent portions of Colorado, Arizona, and New Mexico, where it is 

associated with characteristic fossils of the Colorado formation, such 

as Inoceramus labiatus, Inoceramus fragilis, and many others. It is 

reported from this horizon at many localities by Dr. dewberry.2

It was collected by Mr. C. D. Walcott about 350 feet above the base 

of his Cretaceous section in Upper Kanab valley, Utah, and the speci1 For discussions of Gryphcea pitcheri and its varieties see K. T. Hill in Ann. Kept. Arkansas Gool. 

Sur., 1888, Vol. n, pp. 168-174, and Bull. No. 4, Tex. Geol. Sur., p. 4, and Jules Marcou, Am. Geologist, 

Vol. in, p. 188.

3 Macomb's Expl. Exped. Geol. Kept., pp. 33,52,71,87,107, etc.
62 COLOKADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL. 106.

mens described by Dr. White came from the same general region. 1 

have collected it near Mancos, in southwestern Colorado, from shales 

overlying sandstones referable to the Dakota formation and just 

beneath a band of limestone containing Inoceramus labiatus. This 

difference in geologic horizon would not justify the separation of these 

fossils from G. pitcheri if they were identical in form. But while there 

is a general resemblance, and possibly examples of the G. pitcheri of 

Texas might be selected that could not be distinguished from some of 

the western ones, the differences are as a rule sufficient to make them 

easily separable. The fact that the western form occurs in later beds 

and that all its faunal associates are different necessarily gives greater 

importance to slight differences in form. Compared with typical examples of G. pitcheri it has broader and less distinct beaks, smoother 

surface And more rounded outlines, and it never attains so large a size. 

The specimen represented by PI. v, Figs. 3 and 4, is the largest I have 

seen.

Some of the smaller examples have a superficial resemblance to 

GrypJicea, vesicularis var. aucella Roeiner, but the latter is more alate 

and its beak is not so much incurved.

Of European species small examples of Ostrea proboscidea Archiac 

and some specimens of Ostrea vesiculosa Gue"ranger as figured by 

Coquaud 1 closely resemble this species.

Genus EXOGYRA Say. 

EXOGTRA SUBORBICULATA Lamarck (sp.).

PI. V, Fig. 6; PI. vi, Figs. 1 and 2; PI. vm, Fig. 1.

GrypUtta siiborbiculata Lamarck, 1802, Systeme des Animaiix sans Verte"bre8, p. 398.

Grypliites ralisbonensis Schlotheim, 18 L3, Min. Tasch., vol. vn, p. 105.

Gryphcea columba Lamarck, 1819, op. cit., vol. vi, p. 198.

Ostrea ratisbonensis Coquand, 1869 (with full synonymy), Monog. Gen. Ostrea, Terr.

Cr4t., p. 121. 

Exogyra suborbiculata Stoliczka, 1871, Cret. Pelecypoda of Southern India, p. 462.

Shell large, comparatively thin, irregularly suborbicular or subovate 

in outline. Lower valve very convex; umbonal region narrow and 

prominent; beaks relatively small, distinctly coiled, more or less separated from the body of the shell'. Full-grown individuals have a broad 

distinct furrow or depression extending obliquely from the umbonal 

region to the postero-basal margin. . Surface smooth, marked only by 

lines of growth. Upper valve represented in the collection by fragments that show that it was suborbiculate, nearly flat, with distinctly 

coiled beak arid marked by obscure concentric ridges near the periphery.

An average sized specimen gives the following measurements: 

Length from beak to base, 82mm ; greatest transverse breadth, 80mm j 

convexity, about 43mm.

1 Monog. Genre Ostrea, Terr. Cret., pis. 16 and 59.
STANTON.] OSTKEID^E. 63

The fossils from Colorado above described seem to agree in every 

respect with many of the published figures of the common European 

species that is usually described under the name of Ostrea or Exogyra 

columba. The differences are certainly not greater than those shown 

by some of the forms referred to the species by European authors. 

The species is known to have a wide geographic distribution, occurring 

throughout Europe and in southern India in the Middle Cretaceous 

(Cenomanian and Turonian). It is said to be best developed in the 

zone with Inoceramus labiatus. With these facts before us it ought not 

to be surprising to find the species associated with a similar fauna in 

this country. On the contrary, it is strange that it has so long escaped 

observation here.

Exogyra columbella Meek may prove to be only the young or a variety of this species, but the two forms have not yet been found associated at the same localities, and it is thought best to treat them separately for the present.

' Locality and position. In the Pugnellus sandstone near Malachite 

post-office and Poison canyon, in Huerfano park, and at about the 

same horizon at Rattlesnake butte and on the Arkansas river, 20 miles 

above Pueblo, Colo.

EXOGYRA COLUMBELLA Meek. 

PI. vm, Figs. 2, 3, and 4.

Exogyra costata, var. fluminis White, 1876, U. S. Geog. & Geol. Sur. West 100th

Meridian, vol. iv, p. 174, PI. 17, Figs. 3a-d. 

Exoyyra columlella Meek, 1876, Maeoinb's Expl. Exped. from Santa F6 to junction of

Grand and Green rivers, p. 124, PI. i, Figs. 3o-d; White, 1884, 4th Ann. Eept.

.U. S. Geol. Sur., p. 304, PL 55, Figs. 5 and 6.

Prof. Meek's description and comments are as follows:

" Shell small, rather thin, ovate; posterior side forming a semioval 

curve from, the umbo to the ventral edge; anterior side rounded below 

the beak; ventral margin rounded. Lower valve convex, the most 

gibbous part sometimes forming an obtuse umbonal prominence, which 

is not separated from the front by a sulcus; beak slenderj pointed, and 

distinctly coiled to the left; surface ornamented by small, but distinct, 

rather regular, radiating costse, which bifurcate along the umbonal 

ridge; marks of growth rather obscure. Upper valve flat, oval, apparently smooth, or only having obscure lines of growth. ,._

" Length from the most prominent part ef the umbo to the ventral 

margin, 1 inch; transverse breadth, 0.72 inch; depth or convexity, 

about 0.42 inch.

"It is possible that this shell maybe identical with J3. Iceviuscula of 

Roomer,1 but with the means of comparison now within my reach I can 

but regard it as distinct. All the vSpecimens of it that I have yet seen are 

more oval in form and have a less distinctly spiral beak than the form

l Kreid. von Texas, PI. IX, Fig. 3a, b, c.
64 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL. 106.

described by Eoemer. They also differ in having the under valve 

always marked by regular radiatiug costae, while that of E. Icemuscula 

is generally quite smooth, or rarely presents traces of nearly obsolete, 

rather broad, plications, as represented by Fig. 3c of Eoemer's PI. ix 

(Kreid. von Texas). It seems likewise to be a thinner and less robust. 

shell than Koemer's species, and holds a lower stratigraphical position. 

In surface markings, as well as in general form, it closely resembles 

young specimens of E. columba of Lamarck (Anim. sans Vert., VI, 108), 

as figured by Goldfuss in his Pctrefact. Germ., and by d'Orbigny in 

the Paleont. Frariyais. It never attains more than one-eighth the size 

of adult individuals of that species, however, and differs in having an 

oval instead of a circular upper valve."

Locality and position. From the Lower Cretaceous of Dr. Newberry's 

New Mexican section at Covero, New Mexico, and from the base of the 

Middle Cretaceous of the same section at Galisteo, and in the Sierra 

Abajo. The specimens described by Dr. White came from the east 

bank of Eio Puerco, 6 miles below Casa Salazan, New Mexico, and it 

has also been collected in the Lower Cross Timber sands and in the 

Eagle Ford shales of Texas.

EXOGYRA L^EVITJSCULA Eoemer. 

PI. vin, Figs. 5 and 6.

JExogyra laiviuscula Roemer, 1852, Kreidehildungen von Texas, p. 70, PI. 9, Figs. 3a-c;

Conrad, 1857, U. S.'& Hex. Bound. Sur., p. 154, PI. 7, Figs. 4«, 6; White, 1876, U.

S. Geog. & Geol. Sur. West 100th Meridian, p. 173, PI. 17, Figs.2a-d; 1884, 4th

Ann. Kept. U. S. Gepl. Sur., p. 305, PI. 52, Figs. 3,4,5. 

Ostrea fcrdinandi Coquand, 1869, Monog. Gen.Ostrea, Terr. Cre"t., p. 33. 

Exoyyra ponderosa Hill, 1889, Check List Cret. Invert. Fossils of Texas, p. 6.

" Shell of moderate size, capacious, somewhat semiovate in form,

suborbicular in marginal outline; test not massive; larger valve much 

inflated and subheuiispherical; a very indistinctly defined umbonal 

ridge is to be seen upon some examples, especially near the beak, but 

in others this feature is wanting.

" Umbo small, distinctly spiral, making about two volutions, sometimes nearly free, but often very closrly curved, giving the posterior 

side an umbilicated character, sometimes having a very small scar of 

attachment, but often without such a scar, and always quite symmetrical, or at least not distorted, as the beak often is in other species of 

this genus; periphery of its curve usually extending beyond the hinge 

line, but sometimes not. The smaller valve is nearly flat, or slightly 

and somewhat irregularly concave, suborbicular in outline. Surface 

of both valves having a smooth aspect, but it is marked with such 

lines of growth as are common to other genera of shells, and free from 

the lamination of surface so common in the Ostreidse.

"Diameter of the largest example in the collection, from umbo to 

basal margin, 47'""'; transverse diameter, 42inm ; depth of the larger 

valve, 28mm.
STANTON.] OSTREID.E. 65

"The collections contain numerous examples of this species, the typo 

specimens of which were obtained by Dr. Koemer from near San Antonio, Texas. The figure given by Dr. Koemer (loc. cit.) represents the 

the umbo of the larger valve more nearly free than that of any of our 

examples is, the umbo in all of our examples being closely incurved. 

In this respect ours are more nearly like those figured and described 

by Conrad.

"Position and locality. Strata of the Cretaceous period, Linear plateau, southeastern Utah."

The above description is quoted from Dr. White's report in the Survey West of the one hundredth Meridian. Coquand proposed a new 

name for the species because Minister had previously described an 

Ostrea Iceviuscula, but as Miiiister's species was not an Exogyra the 

change was unnecessary.

It may be that Mr. R. T. Hill is right in regarding these fossils as 

young individuals of Exogyra ponderosa: The fact that they occur 

together would cause one to suspect their identity, but those described 

under the name E. Icvviusuula are smoother shells, with a more nearly 

circular outline and less angular umbonal region than E. ponderosa, 

even when of the same size.

EXOGYRA PONDEROSA Eoemer. 

PI. vii, Figs. 1, 2.

Exogyra pondcrosa Koemer, 1852, Y ;eidebildungen von Texas, p. 71, PI. 9, Figs. 2a, I;

White, 1876, U. S. Geog. & Geol. Sur. West 100th Meridian, vol. iv, p. 172, PI.

14, Figs, la-c; 1884, 4th Ann. Kept. U. S. Geol. Sur., p. 306, PI. 50, Figs. 1, 2, 3. 

Exogyra costata, var. Con., 1857, U. S. &Mex. Bound. Sur., vol. i, p. 154, PI. 8, Fig.

3, PI. 9, Fig. 1. 

1 Exogyra, fimbriata Con., 1857, Ibid., PI. 7, Figs. 2a, I.

" Shell large, capacious; marginal outline irregularly subovate; larger 

valve very gibbous; umbo distinctly spiral, but the coil is usually 

obscured by a large scar of attachment; umbonal half obtusely carinate, the sides sloping abruptly from the carina to the margins; basal 

half not so deeply, but more regularly convex than the other. Test 

very massive, sometimes having a solid thickness of five or six centimeters, lamellose, so much so that the valve often splits into numerous 

pieces along the surfaces of the layers of growth; inner surface smooth; 

muscular scar of moderate size, somewhat deep, placed about midlength 

of the valve, and, as usual, a little nearer to the posterior than to the 

anterior side; surface marked by strong, irregular, imbricating lamellae of growth, which become laciniate at and near the margins; surface 

also marked by fine concentric strite, and by irregular, indistinct, radiating coste, the latter being usually removed by exfoliation from old 

shells. The collections do not contain any example of the upper valve, 

but both Eoemer and Conrad describe it as thick, concentrically laminated; smooth within; umbo horizontal, distinctly spiral, 

Bull. 106 5
66 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL. 106.

"Length of an example rather under the average size,from umbo to 

basal margin, about 1 d111 ; breadth, Scm ; convexity of the large valve, 

nearly 6cm .

"Among the numerous examples of this species in the collections, 

none, except the one figured, show the radiating costse, and these costce 

seem to be quite different from those, at least of the typical forms, of 

 E. costata Say. Mr. Conrad st ates, however, that in New Jersey, Alabama, and Texas every intermediate gradation of form and character is 

found, from typical forms of E. costata to E.ponderosa. Judging from our 

examples alone, no person would suspect such specific relationship; 

and, in want of any intermediate forms for personal examination, I 

prefer at present to place our examples under the designation given by 

Dr. Eoemer.

"Position and locality. Strata of the Cretaceous period; east of Impracticable ridge, Utah."

The above is Dr. White's description of the Utah fossils which do 

not differ in any respect from examples collected at Eoemer's typical 

locality. Mr. E. T. Hill has shown that in Texas the typical Exoyyra 

costata is characteristic of the uppermost beds of the Cretaceous, while 

E. ponderosa occurs at a lower horizon, ranging down as low as the 

Austin limestone. My observations in Texas and several other southern states have confirmed this fact. It is therefore better as a matter 

of convenience and for use in geologic work to keep these varieties 

under separate specific names.

ANOMIID^E. 

Genus ANOMIA Linnseus.

.ANOMIA SUBQUADRATA n. sp.

1 PI. vin, Figs. 8 and 9.

Upper valve subquadrate in outline, thin and pearly, varying greatly 

in convexity; cardinal margin straight, or very slightly arched, about 

half as long as the greatest antero-posterior diameter of the shell; posterior margin nearly straight in the middle and rather abruptly rounded 

above and below to join the cardinal and ventral margins respectively; 

ventral and anterior margins forming a continuous curve, which is more 

narrowly rounded in the middle; beak inconspicuous, submarginal. Surface marked by obscure, concentric undulations and lines of growth, 

and very faint traces of radiating striae.

The figured types have the following dimensions: Height, 20 and 

23"""; transverse diameter, 22 and 23min ; convexity, 6 and 3mm .

This species has some resemblance to Anomia nitida Meek.1 It is 

possible that they may prove to be identical when good material for

'Macomb's Expl. Expcd. from SanUFS to junction of Grand and Green rivers, Geol. Itopt., p. 125, 

pi. 1, rigs. 4» and 6.
STANTON.] ANOMIID.E. 67

comparison is secured, but as A. nitida comes from a considerably 

higher horizon and the original description and figures show a different outline, as well as differences in the surface characters, it is thought 

best to treat them as distinct.

Anomia truncata Geiuitz, as figured by Eeuss, 1 is very much like 

this species.

Locality and position. In the Pugnellus sandstone on Williams creek, 

Huerfano park, Colorado.

ANOMIA CONCENTRICA Meek. 

PI. vm, Fig. 7.

Anomia concentrica Meek, 1860, Proc. Acad. Nat. Sci. Phila., vol. 12, p. 311; 1876. 

Simpson's Kept. Expl. across Great Basin of Utah, p. 359, PI. 4, Fig. 3.

Original description:

"Shell small, thin, subcircular or transversely a little oval; lateral 

extremities nearly equally rounded; cardinal margin rather straight or 

but slightly arched; beak very small, central, compressed, marginal, 

not projecting-beyond^ the._cardmalborder; surface of upper valve 

ornamented by moderately distinct regular, concentric undulations, 

and much smaller obscure lines of growth. Transverse diameter 0.64 

inch; length from hinge to the opposite margin 0.50 inch."

Locality and position. On Sulphur creek near Bear river, Wyoming, 

in whitish sandstone associated with Inoceramus and Ostrea soleniscus. 

I am not positive whether this comes from the bed containing I. labiatus and Pugnellus fusiformis or from a somewhat higher horizon.

ANOMIA PROPATORIS White? 

PI. viii. Fig. 10.

Anomiapropatoris White, 1880, Contributions to Paleontology, Nos. 2-8, p. 14, PI. 12, 

Figs. 15 a and 6, Ann. Eept. U. S. Geol. Sur. Terr, for 1878.

"Shell rather small, irregular, and a little obliquely subovate or 

subcircular in marginal outline; test pearlaceous and moderately thin as 

is usual in Anomia. Upper valve convex; beak small, depressed, not 

quite marginal; surface marked by somewhat coarse, irregular wrinkles 

of growth, by a few radiating wrinkles in the umbonal region and by 

fine, close-set, raised, radiating striae, the latter appearing more distinctly on the forward part of the shell than elsewhere. Under valve 

unknown.

"Length of the most perfect example in the collection, llmm ; breadth, 

10min ; convexity, 5mm .

"This shell resembles A. gryphorhyncJms Meek, the typical examples 

of which are from the Laramie strata of the Bitter Creek series, south1 Versteio Bobm. KreiUef., II, p. 45, pi. 31, Figs. 12-14.
68 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BDix.,100.

ern Wyoming, but it differs from that species in having a less promiinent and rounded umbo; in possessing radiating and concentric 

wrinkles and radiating raised striae, while that species is an unusually 

smooth one. In the possession of the radiating raised striae it corresponds closely with A. micronema Meek, which is so commonly distributed throughout the Laramie group. As this striation constitutes n 

more important characteristic than mere form, which is always variable 

in this genus, it strongly suggests an intimate generic relation for our 

shell with A. micronema."

The specimen now under consideration is slightly more irregular in

form and bears rather stronger radiating striae than the type; but the

. variation is not greater than is often observed in species of this genus.

At Coalville, Utah, in the same stratum from which the type was 

obtained, much larger specimens have been found that doubtless belong to this species. They have the same form of outline, but are less 

convex. Casts of similar specimens occur in Huerfano park, Colorado, 

where they are associated with others (described above) that seem to be 

specifically distinct.

Locality and position. The specimen figured is from the Pugnellus 

sandstone on Muddy creek, Huerfano park, Colorado. The type of the 

species was found at a higher horizon in the u third ridge " at Ooalville, 

Utah.

ANOMIA f OBLIQUA M. & H.

Anomia oWiqua Meek & Hayden, 1860, Proc. Acad. Nat. Sci., Phila., p. 181. 

Anomiaf obliqua Meek, 1876, U. S. Geol. Sur. Terr., vol. ix, p. 22, PI. 9, Fig. 2.

This species, which is represented by a single valve, the type, is said 

to come from the Mobrara division of the Upper Missouri Cretaceous, 

near the mouth of the Mobrara river. Although the internal characters can not be seen, I am confident that the type is an Ostrea, and 

probably an immature individual of 0. patina, M. & H.

Genus PLACUNOPSIS Morris & Lycett.

PLACUNOPSIS"? HILLIAEDENSIS White.

PI. vin, Fig. 11.

Placunopsis liilliardensis White, 1879, Ann. Rept. U. S. Geol. Sur. Terr, for 1877, p. 

278, PI. 7, Fig. 14a.

Original description:

" Shell small, broadly oval or subcircular, slightly oblique; test thin, 

fragile, papyraceous; margins somewhat irregular; upper valve moderately convex; umbo submarginal, the apex depressed and not clearly 

defined. Surface conspicuously marked with numerous coarse, radiating, irregularly undulating, abruptly raised lines, which are wider than 

the space between them, and some of which appear to have ended at 

the border, or upon imbricating concentric lines, as tubular or semi-
STASTOS.J SPONDYLIDJE. 69

cylindrical processes. Diameter of the few examples obtained, about 

12 llim .

"Although the hinge and interior of this shell are not known, it 

seems to be a species of true Placunopsis Morris & Lycett, and to be 

nearly related to their typical species, although the latter (P. jurensis 

M. & L., Monog. Gr. Ool. Mol., p. 6, PI. 6, Figs. 8, 8a, and 8&) is ot 

Jurassic age, while the former is Cretaceous. This appears to be the 

only known species of this genus in the Cretaceous rocks of the United 

States, but Mr. Meek1 suggests that the Anomia subtrigonalis of Meek 

and Hayden from the Fort Pierre group of the Upper Missouri probably belongs to the genus Placunopsis. Our species differ conspicuously from, that one in being radiately marked, and also in the character of its marginal outline and general aspect.

"It is true that neither the under valve nor the interior of our species

is known; but the characters, so far as they are known, very plainly 

indicate the genus to which it is referred. In its marginal outline and 

surface markings it resembles the Capulus occidentalis of Hall and 

Meek, from the Upper Missouri river region, as figured by those 

authors, but the distinct laminated pearly texture of the shell substance would forbid its reference to that genus if its other characters 

were less doubtful.

" Position and locality. Strata of the Fox Hills group, near Hilliard 

station, Union Pacific railroad, Wyoming."

Additional collections from the neighborhood of the original locality 

have added nothing to our knowledge of the generic relationship of 

this species. It seems to me that shells of this type should be referred 

to Anomia, at least until their internal structure is known. When 

this description was written all of the Cretaceous sandstones in the 

neighborhood of Hilliard, which is on Sulphur creek not far from Bear 

river, were referred to the "Fox Hills" or Montana formation. It is 

now known that a large part of these sandstones belong to the Colorado, but it has not been definitely determined whether the uppermost 

beds containing this species, Neritina incompta and a few other forms, 

should be assigned to it or to the Montana.

SPONDYLID^-E.

GENUS PLICATULA LAMARCK.

PLICATULA HYDROTHECA White.

PI. ix, Figs 1 and 2.

Plicatula hydrotheca White, 1876, Geol. Uinta. Mts. p. 113; 1879, lltli Ann. Eopt. U. 

S. Geol. Snr. Terr., p. 279, PI. 6, Figs. 3a and I.

Revised description: 

" Shell of ordinary size, a little obliquely and irregularly subovate 

in marginal outline; rostral region narrowed, its sides nearly straight

1 U. S. Geol. Surv. Terr., vol. ix, 4to., p. 23.
70 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL.IOG.

or only slightly convex; tlie remainder of the free border somewhat 

regularly convex or rounded; lower valve broadly convex; hinge-teeth 

well developed; ligamental fosset moderately large; upper valve nearly 

flat or slightly concave in the rostral region. Surface of both valves 

marked by small, slightly raised, radiating plications, which are crenulated, a little irregular, increase in number both by bifurcation and 

implantation, and are more or less distinct upon all parts of the surface 

of both valves.

" Length, 3 cra ; greatest breadth, 24 mm.

" Position and locality. Cretaceous strata, probably equivalent with 

the lower portion of the Colorado Group; head of Water-pocket canyon, 

southern Utah.

" Collected by Mr. G. K. Gilbert."

Only the original types, which are imperfect casts in sandstone, have 

been found. It is possible that better collections would show that this 

species is the same as Plicatula arenaria Meek, but with only the 

imperfect material now in hand it is necessary to keep them separate.

PLICATULA ARENARIA MEEK. 

« PI. ix, Figs. 3 and 4.

Plicalula arenaria Meek, 1876, Macomb's Expedition from Santa F6 to junction of 

Grand and Green rivers, Geol. Rept., p. 126, PI. 1, Figs. 5 a, 6, and c.

Original description:

"Shell small, broad-ovate, usually a little oblique; ventral margin 

rounded; sides converging to the beaks at an angle of about 70° to 80°; 

beaks more or less angular. Under valve moderately convex. Upper 

valve nearly or quite flat. Surface of each valve ornamented by eighteen 

to twenty small, rather sharply elevated plications, only about half of 

which extend to the beaks, while the intermediate ones usually extend 

from one-third to one-halfway from the free margins; concentric markings rather obscure.

"Length from beak to the most prominent part of ventral margin, 

0.50 inch; transverse diameter, 0.43 inch; convexity, 0.11 inch.

"Eesembles, in size and form, P. incongzua, Conrad (United States 

and Mexican Boundary Report, vol. I, PI. 6, Fig. 10,1857), but differs 

in not having squamose concentric a markings, as well as in having 

shorter plications intercalated between those that extend to the umbo. 

The substance of the shell must be thin, since the plications are rather 

distinctly marked on internal casts.

"Locality and position. Covero [New Mexico]; Lower Cretaceous 

of Dr. New berry's section."
STANTON.J. LIMIDJ2. 71

Genus LIMA Bruguie're. 

LIMA UTAHENSIS n. sp. 

PI. ix, Fig. 5.

Lima wacoensis White, 1876, U. S. Geog. & Geol. Expl. West 100th Meridian, vol. iv,

p. 176, PI. 17, Figs. 4a, 1), and c. 

Not Lima wacoensis Roein., 1852, Kreide. von Texas, p. 63, PI. 8, Fig. la, I.

Dr. White's description is as follows :

" Shell rather small, moderately convex, oblique, irregularly oval in 

marginal outline; antero-basal margin broadly rounded; posterior margin regularly, but more shortly rounded than the base; front margin 

sub truncate; postero-dorsal margin nearly straight or slightly convex, 

and nearly parallel with the antero-basal margin; hinge short; ears of 

about equal size, small, but distinct, each forming an obtuse angle by 

the cardinal border, and the anterior and posterior borders respectively; beaks small, distinctly defined, projecting a very little over the 

cardinal border. Surface marked by numerous radiating costse, which 

have interspaces of similar or slightly greater width between them ; 

costae becoming smaller upon each side of the umbonal region, and 

absent from the ears.

" The long diameter of the largest example contained in the collections is about 17"""; short diameter, I4mm."

Comparison of the Utah specimens above described with examples 

of Eoerner's species from Texas shows that they are specifically distinct. Lima utahensis differs from L. wacoensis in the following particulars: In form it is considerably less oblique and proportionally 

more ventricose; the radiating costse are more slender and less angulated, more uniform in size, more regularly arranged, and they never 

bifurcate in any of the specimens examined; it is a somewhat smaller 

species, though the valve now figured measures about one-fifth more 

tli an the dimensions above given.

The fact that Lima wacoensis occurs in the Comanche series associated 

with a fauna that is eutirely distinct from that in which L. utahcnsis 

occurs is an additional reason for their separation.

Locality and position. The types are from " southeast of Paria, 

Utah." The specimen figured in this bulletin was collected by Mr. C. 

D. Walcott in Upper Kanab valley, about 350 feet above the base of 

the Cretaceous section there.
72 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL.IOO.

PECTINID^E.

Genus CAMPTONECTES (Agassiz) Meek.

CAMPTONECTES PLATESSA White.

PI. IX, Fig. 6.

Camptoneclesplatessa White, 1874, Expl. & Sur. West of lOOtli Meridian, Prelim. Kept. 

Invert. Foss., p. 25; 1876, U. S. Geog. & Geol. Sur. West lOOtli Meridian, vol. iv, 

p. 176, PI. 17, Fig. 5o.

Eevised description :

" Shell thin, suborbicular in outline; length of hinge-line about equal 

to one-half the transverse diameter; ears well denned by auricular furrows; posterior ear short, flat, its outer margin slightly concave; anterior ear moderately large, marked by distinct lines of growth and obscure 

radiating strise. The anterior ear of the right valve separated from the 

body portion by a deep, rather narrow, and somewhat angular sinus, 

the depth of which is equal to about one-half the length of the ear from 

its outer extremity to the beak. Radiating striae of the surface moderately fine, increasing in number so rapidly that the direction of the 

outer ends of those above the middle of the valve is transverse, and 

farther toward the hinge they are distinctly recurving; the radiating 

lines crossed by fine concentric striae, and occasionally by more distinct 

lines of growth.

" Height and transverse diameter each about 45 mm.

" This species somewhat resembles C. bellistriata Meek and Hayden 

from the Jurassic strata of Dakota; but is proportionally not so broad 

from front to rear, the ears are proportionally a little longer, and the 

radiating striae a little coarser.

"Locality and position. Strata of the Cretaceous period; 50 miles 

north of Camp Apache, and 5 miles west of Mineral Spring, Arizona,"

It also occurs about 350 feet above the base of the Cretaceous in 

Upper Kanab valley, and at the head of Water-pocket canyon, Utah.

AVICULID^E.

Genus AVICULA (Klein) Brugui6re.

AVICULA GASTRODES Meek.

PI. ix, Figs. 7-10.

Avicula (Oxytomaf) gastrodes Meek, 1873, Ann. Kept. U. S. Geo]. Sur. Terr, for 1872,

p. 491. 

Pteria (Oxytomaf) gastrodes White, 1879, Ann. Kept. U. S. Geol. Snr. Terr, for 1877,

p. 280, PJ. 10, Fig. la. 

Pteria (Oxytoma) erecta White, 1880, Proc. U. S. Nat. Mas., vol. in, p. 157, and vol.

iv, Figs. 7 and 8 of plate opposite p. 139. 

-Gomp&Te -Amcltla-corudigera Zittel, 1866, Bivalv'en der Gosaugebilde, PI. 12, Figs. 12a

and 126.

Original description:

11 Shell (as determined from a left valve) attaining a moderately 

large size, subtrigonal in general outline, rather distinctly convex, and
8TAKTOX.] AVICULID^E. 73

having a very slight backward obliquity; basal outline very profoundly 

rounded, the deepest or most prominent part being in advance of the 

middle; posterior margin moderately sinuous below the wing, from the 

extremity of which it ranges obliquely forward and downward, rounding regularly into the base below; anterior margin strongly and subangularly sinuous under the wing, thence descending with a slight forward obliquity and rounding rather abruptly into the base; hinge 

margin longer than the height of the valve, the antero-posterior diameter of which (at any point below) it also decidedly exceeds, ranging 

nearly at right angles to the vertical axis of the shell; beaks distinctly 

convex, rising above the hinge margin, strongly incurved, without obliquity, and situated less than one-third the length of the hinge margin 

from the extremity of the anterior wing, which is sub trigonal in form, 

somewhat convex, a little rounded at the extremity, and very strongly 

separated from the abrupt shell of the umbo by a deep rounded concavity extending from the beak obliquely to the marginal sinus below; 

posterior wing longer and more compressed, narrower, and more angular than the other; both wings, particularly the posterior one, projecting decidedly beyond the .margin of the valve below. Surface only 

showing more or less distiuct lines of growth. (Right valve unknown.)

"Height of left valve, 1.50 inches; length of same below the wings, 

about 1.30 inches; length of hinge-line, 1.90 inches; convexity (of left 

valve alone), 0.40 inch."

The types of Pteria (Oxytoma) erecta are small individuals that apparently belong to the same species. Dr. White's description is as follows:

"Shell rather small, appearing to be nearly erect, but the axis is 

slightly oblique .Jo the hinge-line; both valves convex, but the right 

one less than the left; hinge-line long, much longer than the axial 

length of the shell; posterior wing large, its extremity acutely angular 

and moderately prominent; anterior wing comparatively large, prominent, obtusely pointed, denned from the body of the shell by a sinus 

or furrow in both valves, the direction of which forms a slightly obtuse 

or nearly right angle with the hinge-line; front, exclusive of the anterior wing, nearly perpendicular, the margin forming a nearly regular 

curve from the front all the way around to the posterior side, where it 

is flexed with a backward curve to meet the extremity of the hingeline; umbones somewhat prominent, especially that of the left valve. 

Surface having a nearly smooth appearance, but the lens reveals the 

presence of somewhat regularly disposed concentric lines.

"Length of hinge-line, 32 min ; axial length of the shell, 26rain . (Museum No., 8771.)

"This shell was formerly referred by me (loc. cit.) to the Amcula linguiformis of Shumard, but it differs from that species by having larger 

wings, a much longer hinge-line, and a much less oblique axis. It may 

be compared with P. (0.) salinensis White, 1 but it differs in being less

1 Proc. TL S. Nat. Mus., vol. n, p. 290, PI. 5, Figs. 1 and 2.
74 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL. 106.

robust, having proportionally larger wings, narrower body, and a more 

nearly erect axis."

All the types are in the form of casts in sandstone and more or 

less distorted by pressure. In Huerfano park, Colorado, specimens 

were found that agree very well in form with the types, but some of 

them are very much larger. These retain portions of the shell, showing that it was unusually thick, especially in the uinbonal region, and 

that the surface is marked by fine, closely arranged, concentric lines. 

Associated with these in the same bed there are other, smaller individuals that are much more oblique, some of which are scarcely distinguishable from some specimens of Avicula linguiformis. (See PI. ix, 

Figs. 9 and 10.) But such specimens as that represented by Fig. 8 of 

the same plate are so nearly intermediate between the two extremes 

that I prefer to keep them for the present under the one name. Avicula 

caudigera Zittel, from the Cretaceous of Gosau, is a closely related 

species.

The largest specimen seen, a left valve, measures 73 mm in height and 

61 mm in length just below the wings; greatest convexity of the single 

valve about 15 mm .

Locality and position. The type came from the " second ridge "at 

Coalville, Utah, where it is associated with Gervillia propleura, Pugnellus fusiformis, etc.; the types of Pteria ereeta were found at probably 

about the same horizon in Lower Potato valley, southern Utah, and 

the specimens now figured come from the Pugnellus sandstone in Poison canyon and on Williams creek, Huerfano park, Colorado.

Genus GEEVILLIA Defrance.

 

GERVILLIA PROPLEURA Meek (sp.).

PL x, Figs. 1,2, and 3.

Avicula (Pseudoptera) propleura Meek, 1873, Ann. Kept. U. S. Geol. Sur. Terr, for 1872,

p.489.

Avicula (Pseudoptera) rhylopliora Meek, 1873, ibid., p. 490.. 

Pteria (Pseudoptera) propleura White, 1879, Ann. Rept. U. S. Geol. Sur. Terr, for 1877,

p. 281, PL 10, Figs. 2a, &, c. 

Compare Gervillia gregaria Sliumard, 1860, Trans. St. Louis Acad. Sci., vol. 1, p. 606. 

Shell very inequivalve, more or less oblique, varying in outline from 

obliquely ovate-subtrigonal to rhombic-suboblong, nearly twice as high 

as wide; left valve moderately convex, with the greatest convexity 

toward the anterior side just belo^w the beaks on the umbonal slope, 

which is here somewhat angular, but becomes broad and flat towards 

the basal margin; beak small, pointed, almost terminal and projecting 

but little beyond the hinge line; the small area in front of the beak 

rather abruptly depressed, forming a more or less distinct anterior 

auricle; posterior alation represented by a broad triangular flattened 

area, not distinctly defined from the body of the shellj hinge-line
AVICULID^E. 75

straight, about as long as the greatest antero-posterior diameter, and 

forming an angle of 50° to 70° with the umbonal ridge; hinge area comparatively narrow, with live or six (or possibly more) large cartilage 

pits, each of which is nearly twice as broad as the space between them; 

posterior margin nearly straight in the middle, but curving slightly 

forward above, where it joins the hinge-line at an angle of 100° or 

more, while below it curves more sharply into the rather narrowly 

rounded base; anterior margin almost parallel with the posterior, 

slightly convex in outline; surface with more or less distinct lines ot 

growth, which are crossed on the anterior part of the valve by several 

fine radiating lines and one or two stronger costae that extend above 

the umbonal slope, giving it an angular appearance. These radiating 

lines are usually distinct on young individuals and become obsolete or 

disappear entirely on adult shells, Eight valve known only by fragmentary casts, which show that it was flat and smooth and did not 

have a byssal notch.

Height of left valve of a large specimen, 87mm ; length of the hingeline, 52inm ; convexity, 22mm .

The types of this species, which was originally described under the 

two specific names cited above, came from the sandstones of the " first 

ridge " at Coalville, Utah, where the fossils are preserved in the form 

of casts that retain both the external and internal features to some extent without showing either very clearly. Afterward Dr.Whiteobtained 

larger collections from the same place which enabled him to prove that 

the two forms are not specifically distinct. In my collections made in 

Huerfano park, Colorado, from about the same horizon there are several 

better preserved specimens, clearly belonging to the same species, in 

which the cartilage pits were observed, though the hinge can not be 

well figured from the material in hand. The transverse folds along the 

hinge-line, shown in one of the types, doubtless represent the cartilage 

pits as modified by pressure, though, of course, they do not show their 

form. Some of the casts show traces of two or three very oblique 

linear teeth below the pits. Traces of the same ninge structure are 

observable on some of the Coalville specimens. These facts are considered sufficient to justify the reference of the species to Germllia. 

The published figure of Oervillia gregaria Shumard, which comes from 

approximately the same horizon in Texas, is very similar to small specimens of this species.

Locality and position. Sandstones of the first and second ridges 

about 800 feet above the lower bed of coal at Coalville, Utah. It also 

-occurs in thePugnellus sandstone on Williams creek and Muddy creek, 

Huerfano park, Colorado, and I have collected the same species near 

the base of the Upper Cretaceous on the Chattahoochee river, 9 to 12 

miles below Columbus, Ga.
76 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL. 106.

Genus INOCERAMUS Sowerby.

INOCERAMUS FRAG-ILIS H. and M.

PL xi, Figs. 1-5.

Inocwamus fragilis Hall and Meek, 1856, Mem. Am. Acad. Arts, and Sci. n. s., vol. v, 

p. 388, PI. 2, Fig. 6a and 6; White, 1876, U. S. Geog. and Geol. Sur. west of 100th 

Meridian, vol. iv, p. 178, PI. 15, Fig. 3; Meek, 1876, U. S. Geol. Sur. Terr., vol. 

ix, p. 42, Figs. 1 and 2 in text and PI. 5, Fig. 5; Meek, 1876, Macomb's Expedition from Santa F6 to junction of Grand and Green rivers, Geol. Rept., p. 127, 

PI. 1, Fig. 6; Whitficld, 1880, Geol. Black Hills of Dakota, p. 390, PI. 9, Fig. 10.

Inoccramus howclli White, 1876, Geol. Uinta Mts., p. 114; 1879, llth Ann. Rept. U. S. 

Geol. Sur. Terr., p. 284, PI. 4, Figs, la, I, c.

Inooeramusperplexus Whitfield, 1880, Geol. Black Hills of Dakota, p. 392, PI. 8, Fig. 

3, and PI. 10, Figs. 4 and 5.

The original description and figures were taken from a small imperfect specimen in which the anterior border was mistaken for the hinge 

line. After studying better material from the same horizon and in part 

from the typical locality, Prof. Meek drew up the following description:

" Shell thin, broad-subovate, higher than long, moderately convex, 

subequivalve; anterior side vertically truncate from the beaks with a 

slightly concave outline; basal and posterior borders forming a more 

or less regular, nearly semicircular curve; hinge line rather short, and 

standing nearly at right angles to the truncate anterior. Beaks pointed 

equal, scarcely rising above the hinge, .curving inward and slightly forward at the points. Surface marked by fine lines of growth, and a few 

obscure traces of concentric undulation.

"Height, about 1.43 inches; length, 1.07 inches."

The study of a considerable number of good specimens from Upper 

Kanab valley, southern Utah, and from Huerfano park, Colorado, in 

connection with the types of Inoceramus perplexus and 1. lioivelli and 

the specimens of J. fragilis -figured by Meek, have convinced me that 

these all belong to one variable species. The differences observed, 

however, are partly due to differences in the state of preservation. In 

some individuals the surface is almost smooth, even when the shell 

has attained considerable size, while others, such as the types of I. perplexus, are marked with very distinct concentric ridges. The variety to 

which the name I. howelli was given differs from the typical form in 

being slightly more convex and more inequivalve, in having a distinct 

posterior auriculation and a broad, shallow furrow on each valve extending from the umbonal region to the postero-basal margin, where it 

forms a slight emargination. Nearly all of the specimens from Huer-- 

fano park, Color ado,, might be referred to this variety, but none of the 

features on which it is based are constant, so that in a large series 

every gradation between it and the typical form may be found.

Locality and position. The original type came from near the mouth of 

Vermilion river, on the Missouri, at or near the base of the Fort Benton
STANTON.] AVICULID^E. . 77

group. It has also been found at about the same horizon near Fort Benton, Montana, in the Black hills of Dakota, and at the Yado del Chama, 

New Mexico. It occurs about 350 feet above the base of the Cretaceous 

section in the TJpper Kanab valley, southern Utah; also in Lower Potato 

valley and on Ashley? s fork, Utah; at the latter place in strata that 

were probably erroneously referred to the Fox Hills. It is abundant in 

the Pugnellus sandstone which caps the Benton shales in Huerfano 

park, Colorado.

INOCERAMUS LABIATUS Schlotheim. 

PI. X, Fig. 4; PI. XIY, Fig. 2.

Ostracites labialus Scliloth., 1813, Broim's Jahrb., vol. vn, p. 93. 

Mytulties yroUematicw Schloth., 1820. Petrefaotenk. r, p. 302.

Inoceramua mytiloides Mantel], 1822, Geol. of Sussex, p. 215, PI. 28, Fiff. 2.

llnoccramus confertim-annulatus Schiel, 1855, Pacific R. R. Reports, vol. n, Pt. 2, p. 108,

PI. 2, Fig. 7.

^Inoceramus pseudo-mytiloides Schiel, 1855, Ibid., PI. 3, Fig. 8. 

Inoceramus mytiloides (Mantell) Room., 1852, Kreide. von Texas, p. 60, PI. 7, Fig. 5. 

Inoceramus mytilopsis Conrad, 1857, U. S. Mexican Boundary Sur., vol. i, Pt. 2, p. 152,

PI. 5, Figs. 6a and Qb. 

Inoceramus problematicus (Schloth.) Meek, 1876, U. S. Geol. Sur. Terr., vol. ix, p. 62, PI.

9, Figs. 3 a and 6.

Inoceramus aviculoides M. and H., 1860, Proc. Acad. Nat. Sci., Phila., p. 181. 

Inoceramus problematicus var. aviculoides Meok, 1876, U. S. Gool. Sur. Terr., vol. ix; p.

63, PI. 9, Fig. 4. 

Inoceramus preblematicus, mytiloides or labiatus of many authors.

" ''. j*'1 '-'. ' -V /.'il/fi/", .*;<",. a.-j

The following is MeekV description of the species:

(i Shell obliquely elongate-oval, subelliptical or ovate, nearly or quite 

equivalve, rather compressed, thin and fragile; anterior side forming a 

slightly convex curve from the beaks obliquely downward and backward; postero-basal extremity rather narrowly rounded; postero-dorsal 

margin very oblique, compressed, nearly straight, or sometimes a little 

convex in outline below the middle, and slightly concave above; cardinal border short, straight, compressed, and forming an angle of about 

45 degrees with the longest diameter of the shell; beaks terminal, 

rather small, nearly equal, obtusely-pointed, rising little above the 

hinge, and not much incurved. Surface ornamented by more or less 

regular, concentric undulations, and smaller marks of growth.

"Greatest length, 4 inches; breadth, at right angles to the longest 

diameter, about 2 inches; convexity of the two valves, about 0.80 inch."

The name Inoceramus aviculoides was applied by Meek and Hayden 

to a variety with a longer hinge line, greater convexity and more prominent beak of the left valve, and with the dorsal region more alate than 

is usual in the species. After studying larger collections Prof. Meek 

found that there were many graduations between this and the typical 

form, and he therefore treated it as only a variety. Like all species of 

the genus, it is subject to considerable variation in form, yet it is
78 COLORADO FORMATION AND ITS INVERIEBRATE FAUNA. [BULL. 10(5.

always easily recognized by its obliquely elongate outline and by the 

character of the surface markings.

It is unfortunate that the law of priority compels us to drop the name 

that has for many years been applied to this species by all American 

writers who have referred to it, and it is the more unfortunate because 

the species is so well known under that name as the most abundant 

characteristic fossil of the Colorado formation. There is no doubt, however, that the American fossil belongs to the species to which European 

paleontologists now apply the earliest name, Inoceramus Idbiatus.

Locality and position. The species is common in the Niobrara limestone of Kansas, Nebraska, Colorado, and throughout the upper Missouri river region. It is also very abundant in calcareous layers of 

the Fort Benton shales wherever they occur in the same regions, and 

it is found in the equivalent strata in Utah, New Mexico, Texas, Northern Mexico, etc. In Europe the species is said to be confined to the 

Lower Turonian and in southern India it is found only in the Ootatoor 

group which forms the base of the Upper Cretaceous section of that 

region.

INOCERAMUS DIMIDIUS White. 

PI. X, Figs. 5 and 6.

Inoceramus dimidius White, 1874; Expl. and Snr. West 100th Meridian, Prelim. Rept. 

Invert. Foss., p. 25; 1876, U. S. Geog. and Geol. Sur. West of the 100th Meridian, 

vol. iv, p. 181, PI. 16, Figs 2ffl, 6, c, aud d.

The revised description is as follows:

" Shell very small for one of this genus, inflated, sometimes much 

so, obliquely subovate in outline; valves subequal, the left one being a 

very little more capacious than the other; test thin; beaks small,prominent, acute, incurving, and pointing a very little forward; hinge-line 

straight or nearly so, rather short.

" Surface marked by more or less regular and more or less strong 

concentric folds or undulations. In some cases these undulations continued to be formed only until the shell had attained about half its full 

size, when they ceased, the rem ainder of the surface being marked only 

by ordinary concentric lines of growth. This irregularity in the formation of concentric folds is sometimes connected with considerable distortion of the usual symmetry of the shell.

"Thelong diameter of an average example from the umbo to the 

postero-ventral margin, 26mra ; greatest breadth, 18mm ; thickness,16ram.

" This species is especially distinguished by its small size. Its other" 

more conspicuous specific characters are the small but prominent and 

pointed beaks and subeqnal valves. From the youn g of I.problematicus, 

the valves of which are also subequal, it differs in the character of the 

beaks just mentioned, the much greater convexity of the valves, and 

other evidences of mature growth.

"The collections contain quite a large number of examples of this
STAHTON.] AVICULID.E. 79

neat little species, both valves of which, in a majority of cases, are together in their natural position.

" Position and locality. Strata of the Cretaceous period; Ojo del 

Piscado, New Mexico."

This species is common at the base of Mesa Yerde, near Mancos, Colo., 

where it occurs in the Colorado formation about 400 feet above its base, 

associated with Prionocyclus maconibi and Ostrea lugiibris. Some examples are much larger than the type, measuring 5cm. in length. All 

the larger specimens are irregular and distorted in shape and with an 

almost smooth surface excepting near the beaks.

INOCERAMUS SIMPSONI Meek. , 

PI. xii, Fig. 1.

Inoceramus simpsoni Meek, 1860, Proc. Acacl. Nat. Sci., Phila., p. 312; 1876, Simpson's Expl. across Great Basin of Utah, p. 360, PI. 4, Fig. 4; 1877, U. S. Geol. 

Expl. 40th Parallel, vol. iv, pt. 1, p. 142, PI. 13, Fig. 4; Whitiield, 1880, Geol. 

Black Hills of Dakota, p. 395, PI. 8, Fig. 1.

Meek's description:

"Shell (right valve) attaining a rather large size, transversely ovalsuboblong, gibbous, the greatest convexity being in the antero-central 

region, cuueate posteriorly; length nearly twice the height; anterior 

end very short and rounded from the beaks; base forming a long, semielliptic curve, most prominent near the middle and somewhat straightened, or even slightly sinuous, posteriorly; hinge-line long, straight, 

and ranging parallel to the longer axis of the shell; posterior margin 

subtruncated, with a slight backward slope above, and forming an 

abrupt curve into the oblique posterior basal margin; beaks depressed 

so as to project a little above the hinge-line, incurved, and placed nearly 

over the anterior margin. Surface ornamented with moderately distinct, regular, concentric Undulations and lines of growth.

"Length, 8.10 inches; height, about 4.30 inches; convexity of right 

valve, nearly 2 inches."

Locality and position. The type specimen, and the only one that 

Meek examined, comes from " North Platte river, above Platte bridge, 

in Dakota Territory, from the Cretaceous form at ion No. 2 or 3 of the 

upper Missouri section." The Dakota examples described by Whitfield 

are from the Old Woman fork in the Fort Pierre group, and from the 

east fork of Beaver creek, in probably the Fort Benton.

INOCERAMUS GILBERTI White.

PL xiv, Figs. 3 and 4.

Inoceramus gilberti White, 1876, Geol. Uinta Mts., p. 113; 1879, llth Ann. Eept. U. S. 

Geol. Sur. Terr., p. 285, PL 3, Figs. 1 o, 6, c.

The revised description is as follows:

" Shell irregularly suboval in marginal outline, the transverse diameter being greater than the vertical; front more or less flattened; valves
80 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL. 106.

nearly or quite equal, the left one, if either, the larger, both of them 

gibbous, and sometimes quite ventricose; umbones broad and elevated; 

beaks very near the frout, incurved, but not projecting beyond the front 

margin; front nearly straight vertically, or sometimes more rounded, 

in the former case forming nearly a right angle with the hinge; front 

margin rounded below to the basal margin, which is broadly convex lor 

more than half the length of the shell; postero-basal margin extending 

obliquely upward, with a slight emargination, to the posterior extremity, which is abruptly rounded to meet the downward-sloping posterodorsal margin; dorsal margin straight, its length equaling more than 

half the long diameter of the shell. Upon each valve there is an obscure radiating depression, or ill-defined furrow extending from the 

umbonal region to-the postero-basal border, and ending there at the 

emargination before mentioned.

" Surface marked by the usual lines of growth, and also by numerous 

extravagant, irregular, concentric folds or wrinkles.

"This species belongs to a section of the comprehensive genus Inoceramus that Brongniart designated under the name Catillus. It is a 

peculiarly well-marked species and readily distinguishable from any 

other published species from American strata.

"Transverse length of an average-sized specimen, 7£cm ; height from 

base to hinge, 5cm.

"Position and locality. Cretaceous strata, probably of the Fox Hills 

group; near Last Chance creek, southern Utah, where it was collected 

by Mr. G-. K. Gilbert."

At the time the above description was written the author of the 

species referred to the Fox Hills group almost all of the Coalville section, a large part of which is now known to belong to the Colorado.

In many respects this species resembles some examples of Inoceramus

flaccidus, which certainly come from the Colorado formation. For 

these reasons it is now placed with doubt in the Colorado fauna.

 INOCERAMUS FLACCIDUS White. 

PI. xni, Fig. 1.

Inoceramus flaccidns White, 1876, U. S. Geog. & Geol. Sur. West of the 100th Meridian, 

vol. iv, p. 178, PL 16, Figs, la and 1Z>.

Original description :

"Shell"large, iriegularly subovate in marginal outline, exclusive of 

the ears, valves subequal, not much inflated; wing moderately large, 

well denned at its inner side by an auricular furrow; hinge line hot 

very long, nearly at right angles with the front of the shell, and only a 

little oblique with the axis; a more or less distinct, but somewhat irregu^ 

lar furrow extending the whole length of the shell from the posterior side 

of the umbo to the postero-basal margin, giving each valve an obscurely 

bilobed appearance; crenulated face of the hinge narrow, crenulations
8TANTON.] AVICULID^E. 81

small; umbtmal region narrow; beaks prominent, curved forward and 

inward; test comparatively thin throughout the whole shell, surface 

having the ordinary concentric lines of growth, and the test is also 

thrown into numerous rude and irregular concentric undulations.

" Length of the largest example in the collection, about 22cm ; greatest breadth, about 15cua .

"This species is remarkable for the rudeness and extravagant irregularity of the undulations of the surface, of which irregularity the outline also partakes, giving the shell a flaccid aspect. The specimens of 

the collection are almost wholly in the form of natural casts, being preserved in a fine-grained calcareous sandstone, some of which is crowded 

with specimens of this species.

11 Position and locality. Strata of the Cretaceous period, 5 miles 

above Pueblo, -Colorado."

This species is not known from any other locality. The only American species resembling it in surface features is Inoceramus yilberti 

White, but the form is quite different in the type, specimens.

INOOERAMUS UMBONATUS M. & H.

PI. xvin, Fi'gs. 1 and 2.

Inoceramus uwibonatus Meek and Haydeu, 1858, Proc. Acad. Nat. Sci., Pliila., p. 50;

Meek, 1876, U. S. Geol. Sur. Torr., vol. ix, p. 44, PI. 3, Figs. !«,*&, c, and PL 4,

Figs, la, I, and 2a, &.

Compare Inoceramus involuius Sowerby, 1828, Min. Conch, vol VI, p. 160, PI. 583. 

Compare also Inoceramus exogi/roides M. and H., 1862, I. tenuirostralus M. auclH.;

1862, and /. capulus Shuniard, 1860, Trans. St. Louis Acad. Sci., vol. i, p. 606.

Revised description: /

" Shell attaining a rather large size, vertically subovate, extremely 

inequivalve; height more than one-third greater than the anteriorposterior diameter; base regularly rounded; hinge and interior 

unknown. Left valve very convex; beak greatly elevated, gibbous, 

strongly and somewhat obliquely involute, so as to form one and a half 

to two entire turns, the point terminating near the anterior side; surface unknown, that of internal casts sometimes showing faint traces of 

concentric undulations. Right valve subcircular, or a little oval transversely, much compressed or nearly flat, excepting in the central and 

umbonal regions, which are moderately convex; beaks rather oblique, 

projecting little above the hinge, and but slightly incurved; surface 

(of an internal cast) ornamented with regular, rather prominent, subangular, concentric undulations, separated by wider rounded depressions.

"Height of left valve, about 7 inches; antero-posterior diameter, 

5-10 inches; convexity, 4-50 inches. Right valve^" height, about 5-70 

inches; antero-posterior diameter, 5-10 inches; convexity, about TOO, 

jnches.

Bull. 106 C
82 COLORADO FOEMATION AND ITS INVERTEBRATE FAUNA. [BULL. 106.

" I had at first remarked that this species is related to I. involutus of 

Sowerby, but I was not at that time aware how very closely it is allied 

to Sowerby's species. After a careful comparison of the additional 

specimens alluded to, with figures and descriptions of I. involutus, they 

are found to agree in so many respects that I would not be surprised 

if a comparison of specimens from these two distant localities should 

prove these shells to be specifically identical. The only differences 

that have thus far been discovered between them are the following: In 

the first place the antero-posterior diameter of I. involutus is less in 

proportion to the height of its left valve than in our Nebraska shell. 

Again, the aperture of its left valve is more nearly circular, being 

slightly higher than wide, while in the shell under consideration, it is 

somewhat oval transversely, being slightly wider than high. A more 

important reason, however, for regarding these shells as probably 

belonging to different species, is the fact that I. involutus occurs in 

France and England in the Upper or White Chalk, while our Nebraska 

shell comes from a formation we have reason to regard as equivalent to 

the Lower or Gray Chalk.

" From the same locality and position as those from which the species 

under consideration was collected, Lieutenant Mullan's party obtained 

another somewhat analogous species, which we have described in the 

Proceed. Acad,. "Nat. Sci. Phila. under the name of L exogyroides. 

Like I. umlonatus, it has a very gibbous left valve, and probably a 

nearly flat right valve; but it will be readily distinguished by the 

much more depressed and oblique umbo of its left valve. This depression of the umbo gives it a nearly circular instead of a vertically oval 

outline.

"Locality and position. Twenty miles below Fort Benton, on the 

Upper Missouri; from the Fort Benton group, or No, 2 of the Cretaceous series."

In this country the species has been found only at or near the original locality and in the Austin limestone of Texas. Dr. C. Schliiter 1 

regards involute specimens as belonging to J. involutus and retains the 

name I. umbonatus for those (including I. exogyroides) in which the 

beaks are not coiled. He states, however, that as all three forms are 

associated in the same strata both in Europe and America, it will probably be found that the greater or less amount of coiling in the beaks is 

not an essential specific character. It should be stated that J. involutus occurs in Germany, in Schliiter's "Emscher Mergel" and in equivalent strata in other parts of Europe, at the base of Senonian, where it 

is associated with Ammonites texamis and Ammonites tricarinatus. The 

relative position of these analogous if not identical form, therefore, is 

not very different on the two continents.

1 J?alw<mtograj>hica, vol. xxiv, p. 272,
8TAOTON.J AVICULID^E. 83

INOCEEAMTJS EXOGYROIDES M. & H. 

PL xvii, Figs. 1 and 2.

Inoccramns exogyroides Meek & Hayclen, 1862, Proc. Acad. Nat. Sci., Phila.,. p. 26; 

Meek, 1876, U. S. Geol. Sur. Terr., vol. ix, p. 46, PI. 5, Figs. 3«, 6, c.

Revised description:

"Shell rather large; left valve suborbicular, its height being a little 

greater than its length from the anterior to the posterior side, very 

gibbous; anterior and posterior sides rounded, and forming with the 

base about three-fourths of a circle, the posterior curve being broader 

than the other; cardinal margin comparatively short, and apparently 

a little arched; beak large, elevated, gibbous, distinctly incurved and 

directed obliquely forward, so as to bring its point near the anterior 

margin; surface of cast smooth, or marked by obscure concentric undulations. (Right valve unknown.)

"Length from anterior to posterior margin, 5 inches; height, 5.50 

inches; convexity, near 3 inches.

"No right valves of this species have yet been found; but, judging 

from the gibbous character and involuted beak of the left valve, it is 

probable that the right will be found to be much more compressed, so 

as to make the shell very distinctly inequivalve. The lateral curvature 

of the beak of the left valve, together with its general form, give it 

much the appearance of some species of Exogyra, as viewed from the 

inner side. Its aperture is transversely oval, the height being to the 

length about as four to five. Remaining portions of the shell show it 

to have been quite thick about the beak, and, as in other species, distinctly fibrous.

"Specifically, this shell differs from the last in being much more depressed and in having its left beak considerably less elevated and 

directed much more obliquely forward, as will be seen by comparing 

Fig. 3 a, PI. 5, with Fig. 2 &, PI. 4. It probably belongs, however, to 

the Volviceramus group.

" Locality and position. Ghippewa point, near Fort Benton, on the 

upper Missouri; from the same horizon as the last."

Larger collections will probably show that this is identical with I. uml)onatus.

INOCERAMUS TENUIROSTRATUS M. & H. 

PI. xvi, Figs. 3 and 4.

Inoceramns tcnuiiMstratus Meek & Hayden, 1862, Proc. Acad. Nat. Sci. Phila., p. 27. 

Inoceramus fenuirpstris Meek, 1876, U. S. Geol. Sur. Terr., vol. ix, p. 59, Fig. 5 iu text.

Revised description:

"Left valve very gibbous, subquadrate in outline; anterior margin 

very short or vertically truncated, with a slightly convex outline, immediately in front of the beak, and rounded into the base below j ventral
84 COLOKADO FORMATION AND ITS INVERTEBRATE FAUNA.

margin nearly semi-elliptical; posterior side rounded, or sometimes subtruncated, with a slightly convex outline above, and a little more prominent and rounding into the base below; hinge of moderate length, 

with cartilage furrows small, there being about five of them in a space 

0.20 inch; beak very gibbous, prominent, narrowed, strongly incurved, 

and directed a little forward, its point being immediately over the anterior margin. Surface of internal cast smooth over the gibbous urnbonal 

regiori, but showing traces of small, concentric undulations below the 

middle. (Eight valve unknown.)

" Length, 2.10 inches; height from base to hinge, 1.82 inches; height 

to top of umbo, 2.13 inches; convexity of left valve, 0.90 inch.

" This shell has a more prominent, attenuated, and strongly incurved 

left beak than any other species of the Catillus group with which I am 

acquainted, being in this respect more like many species of typical 

Inoceramus, while its general form places it with the former section. 

No specimens of its right valve are yet known, but it is probably much 

less convex than the left; I know of no other species with which it is 

liable to be confounded.

" Locality and position. Ghippewa point, Montana; Fort Benton 

group."

This species is known only by the single type specimen, which is evidently somewhat distorted by pressure. I suspect that it is only an 

immature individual of I. umbonatus, although Prof.' Meek placed" it in 

a different subgeuus.

INOCERAMUS UNDABUNDUS M. & H. 

PL xvi, Figs. 1 and 2.

Inoceramus unddbmdus Meek &Hayden, 1862, Proc. Acad. Nat. Sci. Phila., p. 26; 

Meek, 1876, U. S. Geol. Sur. Terr., vol. ix, p. 60, PL 3, Figs. 2a, I.

The following is quoted from the revised description:

" Shell obliquely rhombic-subovate or subquadrate, gibbous; anterior 

side very short, and rounding .obliquely downward into the base; posterior basal extremity prominently rounded; posterior margin broadly 

rounded or subtruncated; dorsal and anterior margin diverging from 

the beaks at an angle of about 90°; hinge short; beaks moderately 

prominent and nearly terminal, that of the left valve rather strongly incurved and directed obliquely forward, while in the right it is straighter 

and less elevated; umbonal axis ranging at an angle of about 70° to 

the hinge line. Surface of both valves (in the condition of casts) ornamented by regular, strong, subangular, concentric undulations, separated by wider, rounded depressions.

"Height from the most prominent part of the base to the hinge 

margin, 2.90 inches; height to top of unibo, 3.36 inches; convexity of 

left valve, 1.84' inches.

u The strong, subangular undulations, and gibbous, obliquely sub-
STAOTON.] AVICULID2E. 85

rhombic outline of this species, will readily distinguish it from all the 

other known forms of the genus in our rocks; and I know of no foreign 

species nearly enough related to it to render a comparison necessary. 

Both of its valves are quite convex, but the left one is rather decidedly 

more so than the right.

!ii One of the specimens of the right valve has its beak so nearly terminal and its anterior margin below it so straightened in outline as to 

present much the appearance of a typical Inoceramus; but as the others, 

as well as the left valve we have figured, have the anterior margin 

more prominent, it is probable that the straightness of the anterior 

outline in the single specimen mentioned may be, to some extent, due 

to accidental distortion.

" Locality and position. Chippewa point on the Missouri, near Fort 

Benton; from the Fort Ben ton group of the upper Missouri Cretaceous 

series. Collected by Lieut. Mullau."

INOCEEAMUS DEFORMIS Meek. 

PI. xiv, Fig. 1; P.l. xv, Figs. 1 and 2.

Inoceramus dcformis Meek, 1871, Ami. Rept. U. S. Geol. Sur. Terr, for 1870, p. 296.

Haploscapha capax Conrad, 1874, Ann. Rept. U. S. Geol. Sur. Terr, for 1873, p. 456.

?Hayloscapha yrandis and Haploscapha eccenlrica Conrad, 1875, U. S. Gool. Sur. Terr., 

vol. n, pp. 23 and 24, Pis. 66 and 67.

Inoceramus deformis White, 1876, U. S. Geog. and Geol. Sur. West one hundredth Meridian, vol. IV, p. 179, PI. 15, Figs.. 1« and I.

Inoccramus deformis Meek, 1877, U. S. Geol. Expl. Fortieth parallel, vol. iv. pt. 1, p. 

146, PI. 14, Figs. 4 and 4o.

Inoceramus ? Hall, 1845, Fremont's Rept. Expl. Rocky Mts., p. 310, PI. 4, Fig. 2.

The following is Meek's description:

" Shell attaining a rather large size, obliquely ovate, and rather compressed in young examples, but more rounded, gibbous, and irregular, 

as well as much less oblique, in adult specimens; more or less inequivalve,but never very decidedly so; posterior and basal margins rounded; 

the latter curving up more gradually and obliquely to the short anterior 

margin; hinge short and usually not very oblique; beaks moderately 

prominent, and placed between the middle and anterior margin; neither 

greatly more elevated than the other. Surface ornamented with large, 

strong, concentric undulations, which are sometimes moderately regular, but often very irregular, and generally becoming rather abruptly 

smaller on the umbones, where their curves indicate the greater obliquity 

of the young shell. ,

"Height of a medium-sized specimen, about 4.50 inches; length of 0 ]£>«? <^«K»~ x ' 6 Si-&>.-..-*. °

same, 4739-rrretres; convexity of right valve, about 2.50 inches.

"I have frequently had under examination, during the last twelve 

years, specimens of this shell, without being able to identify them with 

any described species. Nearly all of the explorers who have visited 

the eastern slope of the Rocky mountains between the south branch
86 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL. 106.

of the Platte river and New Mexico have brought in specimens of it, 

but almost always in a distorted or broken condition. Its distortion, 

however, is evidently, not always due to accident, since it often resulted 

from one of the depressions between two of the undulations being so 

much larger and deeper than the others, as to give the valves a remarkably constricted appearance. In other cases it resulted, in part at least, 

from the great irregularity in the size of the undulations themselves. 

Although it is often found distorted in general form by accidental pressure, it was evidently also naturally quite variable in outline, particularly in convexity."

The name Inoceramus deforinis was first used by Meek in a list without description, but with a reference to Hall's figure in Fremout's report. Conrad refers to the same figure in describing Haploscaplia capax. 

His genus Haploscapha was based on specimens, probably belonging 

to this species, in which the surface of the shell was completely covered 

and cemented together by Ostrea congesta so that the interior only 

could be seen.

Inoceramus erectus Meek, from the upper portion of the Cretaceous 

section at Co'alville, Utah, is closely related to this species, though it 

occurs at a much higher horizon. It seems, however, to be a more constant and regular form. I

Locality and position. Very common in the Niobrara limestone along 

the eastern base of the Front range in Colorado, e. </., at Boulder, Morrisou, Canyon city, Colorado Springs, near Pueblo, and in Huerfano 

park. In this region it seems to be confined to the Mobrara. It is 

also common in Kansas and Nebraska, and I have seen specimens that 

probably belong to this species from the Austin limestone, near Dallas, 

Texas.

INOCERAMUS CONRADI H. and M.

Inoceramus conradi Hall and Meek, 1856, Mem. Am. Acad. Arts, and Sci., n. $., vol. v, 

p. 387, PI. 2, Figs. 5a and I.

This species is based on a single imperfect, crushed specimen which 

was obtained from the lower part of the FortBenton shales on the Missouri, 5 miles below the mouth of Vermilion river. No other examples 

of it have been recorded, probably because well-preserved specimens 

could not be identified by means of the figure.

Genus MODIOLA Lamarck. .

MODIOLA (BRAgHYDONTES) MULTILINIGERA Meek.

PI. xix, Fig. 3.

Mo&lola (Brachydontes) multilinigera Meek, 1873, Ann. Rept. U. S. Geol. Sur. Terr, for

1872, p. 492. 

Folsella (Brachydontes) multilinigera White, 1880, Cont. to Paleontology Nos. 2-8, p.

14, PI. 12, Figs. 15a and &.< Ann. Rept. U. S. Geol. Sur. Terr, for 1878.
Sl'ANTON.] MYT'lLlb^. 8t

Compare Modiola tcnuisculpta Whiteaves, 1889, Cont. to Can. Paleontology, vol. i, p. 

188, PL 26, Figs. 2 and 2a.

Original description :

" Shell rather above medium size, obliquely arcuate-subovate; valves 

strongly convex along the umbonal slopes, thence cuneate posteriorly, 

and abruptly curved inward below the middle in front ; posterior margin forming a broad, regular, convex curve, from the end of the hinge 

downward to the anterior basal extremity, which is very narrowly and 

abruptly rounded; anterior margin ranging obliquely backward and 

downward to the narrow basal extremity, and strongly sinuous along 

the middle, above which it projects more or less beyond the umbonal 

ridge, so as to form a moderately prominent, somewhat compressed 

protuberance; hinge margin nearly or quite straight, running at an 

angle of 50° to 60° above an imaginary line drawn from the beaks to 

the most prominent parts of the basal outline, and equaling about half 

the greatest oblique length of the valves; beaks nearly terminal, rather 

compressed, very oblique, and scarcely rising above the hinge margin; 

umbonal slopes prominent and more or less strongly arcuate. Surface 

ornamented by fine lines of growth, crossed by regular radiating lines 

that are very fine and crowded on the anterior part of the valves, but 

become coarser above and behind the umbonal ridge, the largest being 

near the dorsal side, where they bifurcate so as to become very fine, 

and curve more or less upward before reaching the cardinal margin.

" Greatest length, measuring obliquely from the beaks to the most 

prominent part of the basal margin of a large specimen, 1.90 inches; 

greatest breadth at right angles to the same, 1 inch; convexity, 0.76 

inch.

"On first examining some imperfect casts of this shell, brought by 

Dr. Hayden from near Coalville, Utah, I was led to think it probably 

the form described by Dr. Koeiner from Texas, under the name Modiola pedernalis^ to which I referred it provisionally, in making out the list 

of Cretaceous fossils for Dr. Hayden's report of 1870. Further comparisons of better specimens collected during the past summer at the 

same locality, however, have satisfied me that it presents well-marked 

and constant differences from the Texas shell. In the first place, it is 

distinctly more arcuate, so much so, that when placed with its hinge 

line in a horizontal position, the outline of its posterior margin, instead of forming an oblique backward descending curve, ranges nearly 

vertically. Again, the most prominent part of its posterior basal margin is very narrowly rounded, instead of forming a regular curve. Its 

umbonal ridges are likewise more prominent, more arched, and extend 

down to the narrowly rounded posterior basal extremity. The lobe-like 

projection of the upper part of its anterior margin, under the beak and 

in front of the umbonal ridge, also differs in being proportionally much 

smaller than Dr. Eoemer's species, in which it forms about one-third of 

the entire valve, as seen in a side view, while in our shell it scarcely
88 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL. 106.

forms inore than one-sixth. Of course the specimens are more or less 

variable in these characters, but the two forms can always be readily 

distinguished when good examples can be had for comparison.

" In its more arcuate form our shell agrees more nearly with Modiola 

ornata Gabb, from the Cretaceous rocks of California; but that shell 

differs very markedly in having its beaks decidedly less nearly terminal, and a more decided and much more prominent lobe in front of 

them. Another important difference is to be observed in the radiating 

striae, which, on the anterior side of our shell are very minute and 

closely crowded, while on that part of Mr. Gabb's species they are as 

large and distant from each other as on any other part of the valves."

Whiteaves states that Modiola tenuisculpata is very closely related to 

Meek's species, and as it comes from approximately the same horizon 

in Manitoba it will probably prove to be a synonym.

Locality and position. The types came from the lowest fossiliferous 

bed of the Cretaceous section at Coalville, Utah, where it-is abundant. 

It also occurs at a much higher horizon in the "third ridge" of the 

same section and at several localities in southern Utah. It is common 

in the Colorado Cretaceous beds at Bear River city, Wyoming, and the 

same or a closely related species has been found in the Bear Biver formation on Twin creek, Wyoming.

PINNID^E. 

Genus PINNA Linnaeus. 

PINNA PETRINA White.

PI. xix, Fig. 4; PI. xx, Fig. 1-

/

Pinnapctrina White, 1874, Expl. & Sur. West of 100th Meridian, Prelim. Rept. Invert.

Foss., p. 24; 1876, U. S. Geog. & Geol. Sur. West 100th Meridian, vol. IV, p. 182, PI.

13, Figs, la and 6. 

Pinna stevensoni White, 1880, Proc.U. S.Nat. Mus., vol. in, p. 47. \ ''W i * ! .; '< ' '' ' -'^ ' '' ''".'. » <*. - h---' ' [j'^p , 'i j., 3i . "r '^ 'I Kevised descriptionj^t,,^ /; » Ji; .,,,; , ,<,,,-- ' ' s 

" Shell moderately large, broad, rather thick, rapidly expanding in 

height as it increases in length; dorsal margin concave; ventral margin convex; a more or less strongly-raised carina extending from the 

beak to the posterior margin, denning a prominent longitudinal angle 

along the median portion of each valve, which is placed a little nearer 

the ventral than the dorsal border; transverse section rhomboidal, the 

sides of the rhomb slightly convex; posterior margin oblique with the 

axis of the shell, forming a distinct but obtuse angle with the dorsal 

margin. The acute angle which it would form with the ventral margin 

if continued all the way to it in a direct course is abruptly rounded.

"Surface marked by strong, distinct lines of growth, which run obliquely downward and backward in a nearly direct course from the dorsal margin, across the mesial angle, to near the ventral margin, where
SrANTON.] ' ARCIDJ3. 89

they are abruptly flexed forward, and blend -with the ventral border. 

Crossing the lines of growth upon the surface above the mesial angle, 

there are coarse but indistinct radiating strife, and occasionally still 

more indistinct traces of similar ones below that angle, all of which 

are more discernible upon the anterior than upon the posterior part of 

the shell. More or less of the test is preserved upon all the specimens; 

but no trace of the pearly layer has been detected, all the test having 

the usual prismatic structure.

" Some of the largest examples measure 7£cm in width along the posterior margin, and they must have been not less than 17cin in length when 

entire. The large size, proportionally great width, and angular aspect 

of this shell distinguish it from any other likely to be confounded with 

it. It resembles P. renauxiana d'Orbigny, as figured by him in Pale"ontologie Francaise, but it expands much more rapidly in width than that 

species does, is not proportionally so thick, and has a very different 

posterior marginal outline. In that shell it is the middle of the posterior margin that is most extended, while in ours the greatest extension j 

is much below the middle. ~~

"Position and locality. Strata of the Cretaceous period; east of 

Mount Taylor, 1 mile south of Pajuate, New Mexico."

The type of Pinna stev&$$oni, which was found near Fort Wingate, 

New Mexico, only a few miles from the typical locality of P. petrina, 

seems to be only an unusually large specimen of the latter species. 

The absence of the anterior portion, which is always more angular and 

often bears radiating lines, gives this specimen an unusual aspect.

The exact position of the beds from which the types came is not 

known. The species is not uncommon in the Pugnellus sandstone of . Huerfauo park, Colorado, and a few examples were found in the Benton shales on the Arkansas river, 20 miles above Pneblo, Colorado. A 

Pinna occurs in the sandstone of the " second ridge " at Coalville, 

Utah, that may be this species.

Genus BAKBATIA Gray.

BARBATIA MTCRONBMA Meek (sp.).

PI. xxi, Figs. 1-4.

Trapezium, micronema Meek, 1873, Ann. Rept. U. S. Geol. Snr. Tfirr. for 1872, p. 493. 

White, 1879, Ann. Kept. U. S. Geol. Sur. Terr, for 1877, p. 293, PI. 10, Fig. 5.

Area? coalvillensis White, 1876, Geol. Uinta Mts., p. 115.

JBarbatia coalvillensia White, 1879, Aun. Rept. U. S. Geol. Sur. Terr, for 1877, p. 286, 

PI. 6, Figs. 2a and ft.

The type of this species is a cast of both valves on which the surface 

markings are partially preserved, hut it is broken and distorted by 

pressure, so that the generic features are obscured and the outline is 

not complete. This specimen is from Cretaceous coal-bearing sand-
90 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL. 10C.

stones at Bear Eiver city, Wyoming, and Prof. Meek recognized the 

species in sandstone near the base of the section at Coalville, Utah, in 

the same layers from which the types of Barbatia coalmllensis were obtained. A study of all these types and of large collections from the 

same localities has convinced me that they belong to a single species, 

and that the smaller shells called "Macrodon (undetermined sp.)" by 

Meek are the young of the same species.

White's revised description of the Coalville specimens is as follows: 

" Shell not large, moderately gibbous, transverse length from twofifths greater to nearly twice as great as the height; beaks depressed, 

situated near the anterior end; umbones broad, not prominent; anterior 

end rounded or sub truncate; base usually nearly straight, but sometimes slightly convex and sometimes a little einarginate about the midlength ; postero-basal border rounded upward to the posterior extremity, 

which is abruptly rounded up to the downward sloping, nearly straight 

postero dorsal border, the latter forming abounded obtuse angle with 

the cardinal border; hinge equal in length to about two-thirds the entire 

length of the shell, consisting of a moderately slender hinge plate bearing numerous transverse teeth with about equal spaces between them. 

The posterior teeth have an oblique direction downward and a little forward, Avhich obliquity diminishes towards the front, so that the teeth 

from about midlength of the hinge to the center of the beak are directly 

transverse. These central transverse teeth are a little narrower than 

those farther back, but the two or three teeth in front of the center of 

the beak are larger than any of the others, and a little curved.

"Area apparently nearly obsolete, or at least% it is very narrow. 

Internal markings unknown. A slight depression or flattened space 

upon the outer surface extends from the umbo of each valve to its

base, meeting there the straight or slightly emarginated portion of the

basal margin before mentioned.

"Surface marked by the ordinary lines of growth and also by fine 

radiating lines, which are often obscure.

"Length of an example a little .above the ordinary size, 5rm ; height, 

33 ." - '

Additional material from the original locality shows that in adult 

shells the hinge line is curved downward at each end and in these 

curved portions the teeth are large, slightly curved, and oblique to the 

hinge line, those at the extreme ends, especially the anterior one, 

becoming almost parallel with it. The medial portion of the hinge is 

not so well preserved in any of the specimens, but there are obscure 

impressions of small, closely arranged, transverse teeth. The ligainental area is narrow, with two or three well-defined grooves, posterior to the beak and nearly parallel with the hinge. These features 

are all made out from casts and impressions in sandstone.

In the Timber Creek beds, near Lewisville, Denton county, Texas,
STANTON.] ARCID^E. 91

Prof. "W. P. Cummins and Dr. 0. A. White some years ago obtained 

large numbers of well preserved shells which I believe to belong to 

this species. At any rate, the characters that are preserved in the 

Coalville specimens agree in every particular with those from Texas, 

figures of which are given for comparison.

The species attains a considerably larger size than is indicated by 

the dimensions above given.

Locality and position. Abundant near the base of the Cretaceous 

section at Coalville, Utah, and occasionally found much higher in the 

same section in the lower part of the "third ridge"; also in equivalent 

strata at Bear River city, Wyoming. The Texas specimens come from 

the Timber Creek beds of Den ton county, near the base of the Upper 

Cretaceous section of that region.

Genus NEMODON Conrad.

KEMODON SULCATINUS Evans & Shumard (sp.) 1? 

PI. xxi. Pig. 5.

Area swlcalina Evans & Shuinarcl, 1857, Trana. St. Louis Acart. Sci., vol. i, p. 39. 

Nvmodon sulcatinus Meek, 1876, U. S. Geol. Sur. Terr., vol. ix, p. 82, PI. 15, Fig. 6.

Shell small, transversely elongate, ventricose, basal margin parallel 

to the dorsal, nearly straight, but slightly sinuous in the middle; front 

broadly rounded from the base to the hinge line, which it joins nearly 

at a right angle; posterior end obliquely truncate, strongly sinuous 

above the middle, and narrowly rounded into the base below; beaks 

slightly in advance of the middle, prominent, incurved, and rather distant; posterior umbonal slope oblique, narrowly rounded. A narrow, 

deep sulcus, almost at right angles to the hinge, runs from the beak to 

the middle of the base. Surface of the casts with faint radiating striae, 

and the free margins crenate. A natural mold of the surface of the 

shell shows about 25 fine radiating lines.

Length, 6imn ; height, 3mifl ; convexity of one valve, about 1.6mm.

The specimens here described are a few small casts, the largest of 

which is figured, collected by Mr. C. D. Walcott in the lower part of 

his Upper Kanab valley Cretaceous section, where it is associated with 

many species of the Colorado fauna. The types of the species came from 

near Grand river, Dakota, and the only other reported locality is on the 

Yellowstone river, 150 miles above its mouth, where it is associated with 

species belonging to the Montana formation. The Kanab specimens 

show slight differences when compared with those from the Yellowstone, 

and it is possible that better material will show that they are really distinct; but the general resemblance is very close, and I think it best to 

call them, by the same name for the present.
92 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. 

Genus TBIGOFARCA Conrad. 

TRIGONARCA OBLIQTJA Meek. 

PI. xix, Fig. lj PI. xx. Figs. 2-6.

Cucullosa (Trigonarca?) olliqua Meek, 1877, U. S. Geol. Expl. Fortieth Parallel, vol. IV, 

pt. I, p. 148, PI. 14, Figs. 1, la, I.

Original description:

" Shell" attaining about a medium size, rhombic-subovate, moderately 

convex, the greatest convexity being along the posterior uinbonal 

slope, while the anterior ventral region is abruptly cuneate; anterior 

margin rounded in outline; base with a shallow semiovate outline, 

being usually slightly more prominent in advance of the middle; posterior margin long and very obliquely' truncated, with a slightly convex outline from the hinge to the posterior basal extremity, which is 

prominent and subangular; hinge margin very short, or little more 

than equaling one-third the length of the valves; posterior umbonal 

slope prominent, and more or less angular from the beaks to the posterior basal angle; cardinal area short and rather narrow; beaks moderately prominent, incurved, and placed one-fourth to one-third the 

length of the valves from the anterior margin. Surface ornamented 

by moderately distinct lines of growth, crossed by obscure radiating 

costae that are wider than the mere linear furrows between.

"Length, 1.50 inches; height, 1 inch; convexity, about .70 inch."

This description was based on sandstone casts that retain the surface markings to some extent and at the same time show more or less 

of the internal features.

The collections from several localities in Huerfano park, Colorado, 

contain numerous well preserved specimens of this species, which show 

that the surface is usually marked only by lines of growth, and that 

the obscure radiating costae above described are on the interior of the 

shell, and therefore preserved on internal casts. A few of the smaller 

specimens show obscure radiating lines en the surface, and especially 

on the umbonal ridge. There is considerable variation in outline, some 

specimens having almost the form of Ideonarca depressa White. 

These two species seem to be more closely allied than one would think 

from the examination "of the types alone, but they are probably distinct. The ligamental area is depressed, triangular, with five or six divaricate cartilage furrows. Hinge line curved as in Pectunculus with 

subequal transverse teeth, some of which toward the posterior end are 

slightly larger and curved. Both muscular impressions are bordered 

by elevated ridges, the posterior one being much the stronger. In all 

these generic features Trigonarca obliqua agrees'with the forms on 

which Conrad founded the genus, and specifically it is very closely 

allied to T. triquetra Conrad, from the Cretaceous of North Carolina.

Locality and position. The types were collected in Cretaceous sand-
8TANTON.] ARCIDJE. 93

stones on East canyon creek, Wasatch range, Utah. The species has 

been found near the base of the Cretaceous section at Coalville, Utah, 

and it is common in the Puguellus sandstone on Williams and Muddy 

creeks, and in Poison canyon, Huerfauo county, Colorado.

TRIGONARCA DEPRESSA White (sp.) 

PI. xix, Fig. 2.

Tdonearca dcpressa White, 1876, U. S. Geog. and Geol. Sur. West lOOtli Meridian, vol. 

iv, p. 183, PI. 18, Figs. 13a, &.

Original description:

" Shell of moderate size, gibbous, irregularly trapezoidal or subovate 

in marginal outline; posterior half of the basal margin nearly straight, 

broadly rounding upward anteriorly, and sharply rounding the end of 

the umbonal ridge to meet the posterior margin; anterior margin regularly rounded up to the hinge-line; posterior margin long, about equal 

in length to the full height of the shell, nearly straight or slighly convex, extending obliquely downward and backward; hinge line equal 

to a little inofe than half the length of the shell; areas small, narrow, 

well denned, slightly concave; beaks very small, depressed, a little 

incurved; umbonal ridges very prominent, each bounding anteriorly a 

flattened, three-sided space, along the middle of which there is a radiating, raised line.

" Surface marked by the usual lines of growth and also by numerous 

small, flat, radiating costse of unequal width, with narrow, sharply impressed interspaces between them; costse largest upon and near the 

umbonal ridge, becoming obsolete near the cardinal border, anteriorly 

and posteriorly.

" Length, measuring across at about midheight of the shell, 28mm ; 

height, from base to unibo, 23mm ; thickness, both valves together, 

about 20uim.

11 This species is not fully represented in the collections, but its specific characters are very satisfactorily shown. A full collection of examples would probably show variations of outline, due to sex, in some 

cases, whereby the aspect of the shell may be a little different from 

that of the figure. It is perhaps as nearly related to I. Shumardi Meek 

and Hayden as to any other described species, but it is clearly distinguished from that by its depressed beaks and prorniueiit umbonal 

ridges.

"Position and locality. Strata of the Cretaceous period; east bank 

of Bio Puerco, 6 miles below Casa Salazan, New Mexico."

The species associated' with this at the typical locality belong to the 

Colorado fauna. I have 110 doubt that it is generically related to Trigonarca obliqua and additional collections may show that it is still more 

closely allied to that species.
94 COLOEADO FORMATION AND ITS TNVERTEBEATE FAUNA. [BOLL. 106.

NUCULID^E. . 

Genus 1ST UG TIL A Lamarck.

NUCULA OOLOEADQENSIS n. sp.

PI. xxi, Fig. 9.

Shell small, transversely ovate subtrigonal, moderately con vex 5 dorsal margin iu front of the beak slightly convex, declining to the subangular anterior end; posterior end very short, truncate almost at right 

angles to the dorsum; basal margin forming a regular curve, finely 

crenate within; beak rather prominent, incurved, very near the posterior end of the valve. Surface marked by faint, closely arranged 

radiating lines and by large irregular concentric ridges and lines of 

growth.

Length, 12mm ; height, 10mra ; convexity of single valve, 3mm. 

Only a single well preserved valve of this little shell was found, and, 

not being able to identify it with any of the described Cretaceous species from the Bocky mountain region, I have thought it best to give it 

a provisional name. The fact that the most nearly related forms come 

from a much higher horizon renders it more probable th&t this is a distinct species. In form it is similar to both Nucula planimarginata M. 

& H. and Nucula cancellata M. & H., but the posterior end of our species is proportionally much shorter and there are other slight differences in outline. In surface ornamentation it is more nearly like N. 

planimarginata, but its crenate inner margin would prevent its identification with that species. .

Locality and position. On Williams .creek, Huerfano park, Colorado, 

in concretions near the base of the Fort Benton shales, associated with 

Crassatella excavata.

Genus YOLDIA Mollcr. 

YOLDIA SUBELLIPTICA 11. Sp.

PL xxi, Figs. 6 and 7.

Shell small, thin, transversely elongate subelliptical in outline, moderately convex in the umbonal region, depressed towards the extremities; dorsal margin declining slightly and equally in both directions 

from the beaks; both ends of the shell subangular above and broadly 

rounded below; basal margin almost straight; beaks rather prominent, 

tumid, situated a little behind the middle.

Surface marked by minute concentric lines. Hinge and interior features unknown.

Length, 7mm ; height, 4rnm ; greatest convexity of both valves united, 

S3'"1 .

Not having seen the hinge of this species I am not certain that it 

belongs to the genus to which it is provisionally referred.

Locality and position. In the Pugnellus sandstone, Poison canyon, 

Huerfano park, Colorado, Only one specimen ba.s been found,
STANTON.] TEIGONIID^, UNIONJDJE, SOLEMYID^E. 95

TRIGONIID^E,

Genus TKIGONIA Bruguidre. 

TEWONIA ?

Trigonia Meek, 1873, Ann. Eept. U. S. Geol. Sur. Terr, for 1872, pp. 474,475.

A few imperfect specimens of a Trigonia allied to T. evansana Meek 

have been collected at Cinnabar mountain and near Gallatin city, Montana. The specific characters are not sufficiently well preserved to 

be described. It is remarkable that these are the only specimens of 

Trigonia reported from the Upper Cretaceous of the north interior 

region. The genus is well represented in the beds of the same age in 

the Atlantic and Gulf border regions from New Jersey to Texas, and 

also on the Pacific coast.

UNIONID^E. . 

Genus UNTO Betzius. 

UNIO ? 

PI. xxii, Fig. 1.

Fragments of Uniq are not uncommon, associated with the coal beds 

near the base of the Colorado formation in southern Utah. One of the 

best preserved specimens obtained at Glendale, Utah, is figured. This 

form, which is abundantly represented there by fragments and casts, 

seems to be distinct from all the described Cretaceous species, though 

the material in hand is hardly sufficient to characterize it. It is a rather 

slender, compressed form, its outline broadly lanceolate. The beaks, 

which are not very prominent, are situated one-third to one-fourth the 

length of the shell from the anterior end. The cardinal and basal margins are subparallel, the anterior end regularly rounded, and the posterior end more narrowly rounded or subtruncate. The surface is smooth, 

excepting the posterior third, which is marked by two obscure radiating 

folds or plications. Length of the figured specimen, 66ram ; height, 26mm. 

Some of the fragments belonged to shells nearly twice as large as this.

SOLEMYID^E. 

Genus SOLEMYA Lamarck.

SOLEMYA? OBSCUEAn. Sp.

PI. xxi, Fig. 8.

Shell small, thin, elongate, subcylindrical; ventral and dorsal margins nearly parallel; anterior 1? end regularly rounded; posterior? eno. 

contracted immediately behind the beak, rather narrowly rounded; 

beak broad, incurved, not very prominent? situated near the posterior"?
96 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL. 106.

end. Surface ornamented with faint lines of growth and very obscure, 

distant, radiating lines that are preserved only on the anterior ? portion.

Length, 15mm ; height, 6mm ; greatest convexity of single valve, about 2mm. -j

The type is a single valve, retaining only a portion of the shell. As 

neither the hiuge nor the pallial line has been seen, its generic reference is only provisional.

Locality and position. in the Pugnellus sandstone, Poison canyon, 

Huerfano park, Colorado.

CRASSATELLIDvE.

'Genus CRASSATELLA Lamarck. 

CRASSATELLA EXCAVATA n. sp. 

PI. xxi, Figs. 10-13.

Shell small, depressed subquadrate in outline; dorsal margin nearly 

straight, declining slightly from, the beak to the posterior end, which 

is truncate almost vertically; front slightly concave above for over half 

the distance from the beak to the base and regularly curved below; 

ventral margin forming a broadly ovate curve; lunule broadly lanceolate and very deep; escutcheon long and well denned, but not nearly so 

deep as the lunule; beaks near the anterior end,small, pointed, approximate, and directed forward. Posterior to the umbonal slope, which is 

broadly rounded and not very well defined, the shell is compressed. 

Surface marked by fine lines of growth and by narrow, subequal, somewhat irregularly arranged, concentric ridges.

The hinge has the structure characteristic of the genus and the free 

margin of the shell is crenate. Eepresented by three well preserved 

valves.

Length, 16mm ; height, 15mm ; convexity of one valve, 4mm.

The most nearly related species with which I am acquainted is Grassatella cimarroncnsis White, which has nearly the same outline when 

viewed from the side, but it differs from the present one in its greater 

convexity, larger size, and in the character of its surface. Its lunule 

is proportionally much more shallow and it's hinge is broader and 

stronger.

 - Locality and position. From concretion's in the Fort Benton shales 

on Williams creek, Huerfano park, Colorado.

RUDISTVE. 

C Genus EADIOLITES Lamarck. '

BADIOLITES ?

A single fragment of a large species of Eadiolites, or Splicerulites has 

been collected by Mr. Edwin Blackburn in the Mobrara limestone at 

Morrison, near Denver, Colorado, and I have seen a similar specimen,
STANTON.] LUCINID^E. 97

probably from about the same horizon, that was found near Canyon city, 

Colorado.

The specimen from Morrison is a part of the thick outer layer of the 

lower valve. It shows the characteristic structure of Radiolites, consisting of large prismatic cells arranged in layers parallel with the 

upper surface of the shell, and the surface of each layer showing impressions of a few slender, branched, radiating ridges on one side and 

corresponding furrows on the other. A little of the outer surface of 

the shell is preserved, showing narrow longitudinal ridges and grooves 

each about a millimeter wide. The individual to which this fragment 

belonged must have been 6 or 8 inches in diameter. The shell substance is over 2 inches thick.

Compared with Radiolites austinensis Roemer, which occurs in the 

equivalent of the Colorado formation in Texas, this specimen seems to

have narrower ridges and grooves on the outer surface, while the prismatic cells of the thick shell are larger. It is doubtful, however, 

whether these differences are of specific importance, and I think it 

probable that better material will show that the Colorado specimens 

belong to JK. austinensis.

I Large specimens of u Hippurites" probably belonging to this genus 

have been reported from the Niobrara beds of Kansas.

LUCINIDyE.

Genus LUCIKA. Brugui6re.

LUCINA SUBUNDATA fl. & M.

PI. xxn, Figs. 5 and 6.

Lucina subundata Hall and Meek, 1856, Mem. Am. Acad. Arts and Sci., vol. v (n. s.) 

PI. 1, Fig. 6; White, 1876, U. S. Geog. & Geol. Sur. West 100th Meridian, vol. rv, 

p. 184, PL 18, Fig. 12a; Meek, 1876, U. S. Geol. Sur. Terr., vol. ix, p. 133, PI. 17, 

Figs. 2a, l),c, d, c; Whitfield, 1880, Geol. Black Hills of Dakota, p. 411, PI. 11, 

Figs. 17 and 18.

The following is Meek's description:

"Shell small, subcircular, compressed, very thin; anterior side 

broadly rounded; basal margin semiovate, the most ^prominent part 

being toward the front, more or less contracted behind, smooth within; 

posterior side narrower than the other, and usually subtruncate at the 

extremity; dorsal margin concave in outline just before and convex 

just behind the beaks, which are rather prominent, pointed, and nearly 

central. Surface ornamented by small concentric undulations and very 

small parallel striae, which are sometimes crossed by obscure traces of 

very fine, nearly obsolete, radiating strise.

" Length, 0.42 inch; height, 0.32 inch; convexity, 0.12 inch.

" This little shell evidently varies much in form^ some specimens 

Bull. 106 7
98 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL. 106.

having the anterior portion of the ventral margin much more prominent 

and the posterior side more contracted than Others. Generally there 

is an obscure depression extending obliquely backward and downward 

from the posterior side of the beaks, and a stronger one passing from 

the front side of the beaks to the upper part of the anterior margin. 

Sometimes both of these impressions are obsolete, while in other cases 

they are quite distinct, and there seem to be all gradations between."

The specimens now under consideration, two of which are figured, 

are in the form of ca.sts retaining only small portions of the shell. 

They seem to agree in every respect with the types of the species, 

although they come from a much lower horizon.

Locality dndposition. About 350 feet above the base of the Cretaceous section in Upper Kanab valley, Utah, where it is associated with 

many species characteristic of the Colorado formation. Those described 

by Dr. White came from probably the same horizon southeast of Paria, 

Utah, and it occurs in the lower part of the Coalville section. The 

types and all the other described specimens above referred to were 

collected in the upper part of the Fort Pierre shales on Cheyenne river, 

South Dakota.

LUCINA JUVENIS n. sp. 

PI. xxn, Figs. 2-4.

Compare Lucina subundata M. & H.

Shell small, relatively thick, moderately convex, subcircular in outline; beaks small, central, approximate; dorsal margin slightly concave 

in front of the beaks and convex behind them; posterior end subtruncate, the rest of the outline forming a regular curve. A narrow posterior portion of the shell is considerably depressed. Surface marked by 

distinct regular concentric undulations, each of which is about half as 

broad as the intervening furrows. More numerous fine lines of growth 

are visible under a lens. Length of the largest specimen, 6.4mm ; height, 

6mm ; convexity of the two valves united, about 3mm.

The specimens above described are not easily distinguishable from 

young individuals of Lucina subundata, and if they had been found associated with that species they probably would not have been separated. 

Several examples were collected, all of about the same size, and no 

larger shells of the genus were found in the same beds with them.

Comparison with the types of L. subundata and with the fossils from 

southern Utah that are referred to the same species, show that this little 

shell has relatively less prominent beaks, its outline is more nearly circular, and the concentric undulations are proportionally larger.

Locality and position. In the Pugnellus sandstone near Malachite 

post-office and in Poison canyon, Huerfano park, Colorado.
BTANTON.] CARDIIDJ3. 99

CARDIID^E.

Genus CAEDITJM Linnaeus.

CARDIUM PATJPERCULUM Meek.

PI. xxn, Figs. 9-12.

Cardiumpavperculum Meek, 1871, Ann. Kept. U. S. Geol. Snr. Terr, for 1870, p. 306;- 

AVhite, 1879, idem for 1877, p. 291, PI. 9, Fig. 3o.

Cardium subcurtum Meek, 1873, idem for 1872, p. 476; 1877, U. S. Geol. Expl. 40th Parallel, vol. iv, p. 152, PI. 15, Fig. 3o.

Original description:

"Shell small, very thin, rather compressed, subovale or subcircular; 

beaks moderately prominent and nearly central; surface ornamented

by about thirty regular, simple, distinctly denned, radiating costse, 

which about equal the intermediate furrows, and (owing to the thinness 

of the valves) are well defined internally, and thus impart it plicated 

or crenated character to the margins; crossing these are numerous 

very regular, well-defined, delicate marks of growth that are usually 

less distinct on the posterior third, but give a neatly crenulated appearance to the cosfce further forward.

uThe specimens yet seen of this little shell are rarely more than 

about 0.50 inch in diameter, and are all more or less flattened or otherwise distorted. Sometimes they are distorted by antero-posterior 

pressure, so as to present somewhat the appearance and outline of a 

Lima, being higher than wide, and more or less obliqne, while in other 

examples they are distorted by vertical pressure, so as to present little 

or no obliquity, and to show a greater antero-posterior diameter than 

height. I have not seen the hinge, but some impressions in the matrix 

show that it has anterior and posterior lateral teeth like those of Car- 

 Mum; it, however, does not belong properly to the typical section of 

that genus."

The types are distorted internal casts and molds of the surface, some 

of which show the natural form, and Meek's figure published by White 

(loc. cit.) is an incorrect restoration. The comparison of a large series 

of specimens in all states of preservation has fully established the identity of Cardium subcurtum with G. pawperculum. The sandstone casts 

to which the former name was given were thus described:

11 Shell under medium size, truncato-snborbicular, about as high as 

wide, rather convex, and but'very slightly oblique; beaks nearly central, rather prominent, distinctly incurved almost at right angles to the 

hinge; posterior margin truncated with a slight forward obliquity, so 

as to connect with the dorsal margin at an obtuse angle; anterior margin rounding regularly into the base, which describes a slightly oblique 

semiovate curve, being more prominent behind, where it rounds up 

v,ery abruptly to the posterior margin, so as to give a subangular outline to the posterior basal extremity; umbonal slopes rather prominent,
100 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL.106.

but not angular; hinge margin shorter than the length of the valves 

Surface ornamented by small, regular, simple, radiating costee, and 

moderately distinct lines of growth."

The costce vary in number from thirty to thirty-five and three or four 

of those on the posterior nmboual slope are more elevated, more angular, and farther apart than the others, giving that region of the shell 

an angular appearance when they are not eroded.

Some specimens are nearly circular in outline, the height and length 

being equal, but in most cases the height from beak to ventral margin 

is greater than the length or antero-posterior diameter.

The specimens selected for illustration are somewhat smaller than 

the average size. One from Huerfano park, Colorado^ measures 14mm 

in length, 16" in height, and the convexity of the single valve is 6mm. 

A few examples have been collected that are considerably larger.

Locality and position. The types are from dark-fissile shales near 

the lower part of the Colorado formation, 20 miles west of Fort Bridger, 

Wyoming. It is abundant at the same horizon on Sulphur creek, 

Wyoming, and occurs in the coal-bearing sandstones at that locality. 

The types of Cardium subciirtum Avere collected in the sandstone of 

the "second ridge" at Coalville, Utah, and it is found near the base of 

the same section; also in the Pugnellus.sandstone at several localities 

in Huerfano park, Colorado.

CARDIUM TRITE White. 

PI. xxii, Figs. 7 and 8.

Cardium trite White, 1879, Ami. Rept. U. S. Geol. Sur. Terr, for 1877, p. 291, PL 5, 

Figs. 4«. and b.

Original description:

"Shell broadly subovateor suborbicular, height and width about equal; 

valves gibbous, regularly arching from beak to base; median portion 

regularly convex; sides a little flattened above the middle; rostral portion narrowed, elevated, arched; beaks situated well toward the front, 

much elevated above the hinge-line, prominent, incurved, approximate, 

and turned very slightly, if any, forward; hinge-margin moderately 

long for a species of this genus; front having a short, oblique truncation above, from the lower end of which the whole free margin of the 

shell is continuously rounded to the posterior extremity of the hinge,, 

the convexity varying, but not very greatly, in different parts. Surface 

marked by very numerous fine costse of nearly uniform size on all parts 

of the shell, every third one of which only bears upon its back many 

small nodes or short spines.

"Height from base to beak, 35min ; width, 36min . The height is, however, sometimes greater than the width.

"This species bears more resemblance to C. curium Meek & Hayden 

than to any other species of Cardium yet described from the Cretaceous
8TANTON.] ' CYRENID^E. , 101

rocks of the West, but the prominent umbonal ridge, and the coarser 

and nonspiniferous costse of that species, besides many other details, 

clearly separate it from the species here described ; the peculiar character of the surface markings also separate it from any other described 

species with which it is in any danger of being confounded.

"Position and locality. Cretaceous strata, probably equivalent with 

the lower portion of the Colorado group; head of Waterpocket canyon, 

southern Utah. Collected by Mr. G. K. Gilbert."

CYRENID^E.

Genus CYRENA. Lamarck. 

CYRENA (VELOEITINA) SECURIS Meek. 

PL xxm, Tigs. 1-3.

Corbicula (Cyrena?) securis Meek, 1873, Ann. Rept. U. S. Geol. Sur. Terr, for 1872, p.

494; White, 1879, idem for 1877, p. 289, PI. 3, Fig. 2, a, b, c. 

Cyrena (Veloritina) erecta White, 1876, Geol. Uinta Mts., p. 117. 

Compare Cyrena (Veloritina) durkeei (Meek) White. 1876, U. S. Geog. and Geol. Surv.

West 100th Meridian, vol. iv, p. 207, PI. 21, Figs. 13a, ft.

The original description was based on an internal cast. Near the 

same locality Dr. White obtained well preserved examples which he 

described as follows: *

" Shell of medium size, obliquely subovate in marginal outline when 

adult, but subcircular when young, gibbous, especially the upper 

median portion, but somewhat laterally compressed at the .posterobasal portion; antero-basal, basal, and postero-basal borders form ing a 

continuous, almost regular, curve; the dorsal outline, by lateral view, 

also broadly rounded from the beaks to the postero-basal border; front 

a little concave transversely below the beaks, and also vertically concave from the beaks to a point a little below themidheightof the shell; 

beaks prominent, approximate, and curved forward; ligament short 

and narrow. This concavity of the dor sum resembles an escutcheon, 

except that it is not denned, especially at the ends; it is moderately 

deep, narrow, and bounded at the sides by the abrupt rounding inward 

and downward of the surface from the outer side of each valve, so that 

the hinge margin is wholly hidden from sight by a side view of the 

-shell; hinge and interior unknown. Surface marked by the ordinary 

lines and imbrications of growth.

"Height, 33mm ; antero-posterior width'the same; thickness about 

22mln ."

The additional specimen now before me, though slightly crushedjust 

behind the beak, shows the larger part of the hinge. There are three 

rather small, slightly divergent cardinal teeth (in the left valve) of 

which the middle one is somewhat larger than the others. The lateral 

teeth are long and prominent, apparently not striate.
102 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BOLT.. 106.

Both Prof. Meek and Dr. White have pointed out the close resemblance of this form to CorMcula ( Veloritina) durkeei, a common species 

of the Bear River formation which underlies the beds containing Cyrena 

securis. Some individuals of the former have almost exactly the 

outline of this species, but they are usually larger and thicker shells 

and the hinge seems to be proportionally stronger and with more divergent teeth. I think, however, that they belong to the same genus. In 

southern Utah several forms of Cyrena are common near the base of 

the Colorado formation, where they are associated with Glauconia coalvillensis, Barbatia micronema, Admetopsis, etc. The specimen described by D,r. White as Cyrena ( Veloritina) durkeei came from this 

horizon and might be referred with equal propriety to C. securis. 

Others associated with them approach the form of Cyrena inflexa, and 

still others differ from all those species, though I suspect that they all 

belong to one variable species. (See PI. xxm, Figs. 3 and 4.)

None of the species herein referred to Cyrena are typical examples of 

that genus. They all seein to belong to Meek's subgenus 'Veloritina, 

which he regarded as belonging to CorMcula and which combines some 

of the features of CorMcula, Velorita, and Cyrena, though, as it seems 

to me, somewhat more nearly related to Cyrena than to the other two 

genera.

Locality and position. From the coal-bearing sandstones at Bear 

Eiver city and near Hilliard station, Wyoming, probably near the top 

of the Colorado formation.

CYRENA ^EQTJILATERALIS Meek? 

PI. xxn, Figs. 14 and 15.

Corlicula cequilateralis Meek, 1873, Arm. Kept. U. S. Gcol. Sur. Terr, for 1872, p. 495.

Original description:

" Shell (as determined from an internal cast) subtrigonal, ami nearly 

or quite equilateral, rather convex; height about five-sixths the length; 

anterior and posterior extremities nearly equally, and rather narrowly 

rounded; ventral margin forming a nearly semielliptic curve, the most 

prominent part being at the middle; beaks rather prominent, and very 

nearly, if not quite, central ; umbonal slopes not prominently rounded ; 

dorsal outline declining subequally from the beaks in front and rear, 

the posterior slope being convex in outline, and the anterior concave; 

muscular impressions shallow. (Surface and hinge unknown.)

" Length, 1.72 inches; height, 1.45 inches; convexity, about 0.92 

inch."

This species has never been figured and the type has not been preserved. Eecent collections from, the typical locality contain casts that 

agree well with the description and associated with them, one specimen retaining the shell, which is believed to belong to the same species. 

The beak is about halfway between the middle and the anterior end,
STANTON.] CYKENID2E. 103

but the cast of the same specimen would be much more nearly equilateral. The surface is smooth with obscure lines of growth. The details 

of the hinge are almost precisely the same as in the preceding species, 

excepting that the anterior lateral tooth is much smaller. In form the 

species is closely'related to C. injlexa Meek.

Locality and position. From the coal-bearing sandstones at Bear 

River city, Wyoming, probably near the top of the Colorado formation.

CYKENA INFLEXA Meek. 

PI. xxn, Fig. 13.

Corlicnla (Veloriiina) inflexa Meek, 1873, Ann. Kept. U. S. Geol. Sur. Terr, for 1872,

p. 493. 

Cyrena injlexa White, 1879, idem for 1877, p. 290, PI. 10, Figu. la and Z>.

Original description:

"Shell longitudinally ovate, a little less than two-thirds as high as 

long, moderately con vex ; posterior extremity rather narrowly rounded 

or apparently sometimes faintly subtruncated; anterior very short, subtruncated, or more or less sinuous in outline just in advance of the beaks 

on the abrupt forward slope above, and rather abruptly rounded below; 

basal margin semiovate or semielliptic; dorsal margins inflected and 

forming a long convex slope from the umbonal region posteriorly; beaks 

rather depressed, oblique, incurved, and placed near the anterior end; 

umbonal slopes not prominently rounded; surface merely showing fine, 

rather obscure marks of growth; anterior muscular impression rather 

strongly defined and obliquely ovate; posterior muscular impression 

larger and obscure; pallial line showing a deep, angular, ascending 

sinus; posterior lateral teeth of hinge very long, linear, and nearly or 

quite smooth; anterior short; cardinal teeth very oblique.

" Length of a specimen, a little under medium size, 1.35 inches; height, 

0.39 inch; convexity, 0.68 inch.

"This species is more depressed and elongated than any of those hitherto described from the far western localities, excepting one or two from 

the coal formations on Bitter creek, Wyoming, from which it differs in 

liarving its beaks placed farther forward. It will also be readily distinguished from those shells, as well as from all of the other species of 

the genus yet known, from any of our rocks, by having an angular, 

 ascending, and comparatively deep sinus in its pallial line, almost like 

that seen in many types of the Veneridaj. This character is so strongly 

marked that it was not until I had succeeded in getting a tolerably 

clear idea of the nature of the hinge that I could believe the shell related to the group to which I have referred it. As was pointed out by 

Mr. Tryon, some years back, the existing American species of Cyrena 

and CorMcula have the pallial line more or less sinuous; while in 

nearly all of those from foreign countries it is simple. I have also ascertained that nearly all the extinct North American species yet known
104 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL.IOG.

have the pallial line sinuous. The sinus, however, is usually shallow 

and rounded, or obtuse, in our fossil species; that of the shell here 

under consideration being unusually deep and angular.

"Locality and position. Itfear Missouri river, below Gallatin city, 

Montana, where it occurs, associated with Trigonia, 'Inoceramus, Cardium, Ostrea, and other marine Cretaceous fossils."

CYPRINID^E.

Genus VENIBLLA Stoliczka.

VENIELLA MOETONI M. & H.

PI. xxin, Figs. 6-0.

Venilia mortoni Meek and Hayclen, 1862, Proc. Acacl. Nat. Sci. Pkila., p. 27. 

Veniella mortoni Meok, 1876, U. S. Geol. Sur. Terr., vol. ix, p. 154, PI. 4, Figs. 3«, l>.

Eevised description:

"Shell transversely oblong, or subtrapezoidal in outline, gibbous, 

thick, and'strong; base nearly straight, but rouuding up in front; 

dorsal margin parallel to the base, excepting where it declines, at first 

gently, then abruptly, into the obliquely-truncated posterior; anterior 

side truncated vertically immediately in front of the beaks, just below 

which there is a slight sinuosity of outline, as seen in a side view; 

posterior basal extremity narrowly rounded, or subangular; beaks very 

oblique, strongly incurved, gibbous, and placed directly over the anterior; umboiial slopes forming a prominent, rather angular, oblique 

ridge, from each beak to the posterior basal extremity; lunule and 

escutcheon impressed, but without strongly defined margins; surface

marked with distinct concentric striae, and stronger, irregular ridges, 

the latter of which sometimes pass into regular, rather distant, low 

varices on the umbones.

"Length, 1.66 inches; height, 1.40 inches; convexity, 1.17 inches.

"This species is nearly related, at least in external characters, to V. 

Gonradi Morton, but differs in being more oblique and more depressed 

at the beaks, which are also placed directly over the more truncated 

anterior margin. Its dorsal margin is also longer and less sloping than 

in Morton's species. It will be more readily distinguished from the 

last by its greater proportional length, less angular umbonal slopes, 

and rougher surface.

"I have not seen the hinge of this species; but from, its form and 

general external appearance, there is little reason for doubting that it 

belongs to the genus under which it is placed.

"Locality and position. Chippewa point, on the upper Missouri, near 

Fort Benton; from the Fort Ben ton group of the Cretaceous."

The specimens that are figured on PI. xxin came from the upper 

part of the Fort Benton shales on the Arkansas river, 20 miles west of
STANTON.] CYPRINID^E. 105

Pueblo, Coloraao. They differ from the type in that the beaks are not 

quite so near the anterior end and the posterior end is more narrowly 

rounded, but these differences are not regarded of specific importance. 

This species may also be compared with Veniella humilis M. & H., 

which is found at the top of the Montana formation.

The hinge (of the left valve) is very much like that of V. conradi, the 

type of -the genus there being three strong, thick cardinal teeth and a 

long posterior lateral tooth.

VENIELLA aoNiopHOBA Meek. 

PI. xxin, Fig. 5.

Veniella goniopliora Meek, 1876, U. S. Geol. Sur. Terr., vol. ix, p. 152, Fig. 12 in text, 

and PI. 4, Fig. 4.

" Shell rather thin, short, subquadrate or sub trapezoidal, with length 

only slightly greater than the height, becoming extremely gibbous with 

age, the convexity of large specimens sometimes equaling the length ; 

dorsal outline more or less straightened, or, in large adult specimens, 

curving downward somewhat posteriorly to the rather short, truncated, 

posterior margin; basal margin generally rather deeply rounded in 

outline anteriorly, and straightened or even slightly sinuous and ascending posteriorly, to the posterior basal extremity, which is distinctly 

angular; anterior side narrowly rounded below, and deeply sinuous 

under the beaks above;' beaks prominent, very gibbous, obliquely and 

strongly incurved, in young shells located near the anterior side, though 

not quite as prominent as the margin below, but in the adult sometimes 

overhanging the anterior margin; lunule excavated, but apparently 

not defined by a marginal ridge; posterior umbonal ridge very prominent and strongly angular from the beaks to the posterior basal angle, 

while the space between it and the dorsal margin is concave; surface 

showing concentric striae, and generally a few stronger ridges.

''Length of the largest specimen seen, 1.6(Hnches; height of same, 

1.38 inches; convexity, 1.55 inches.

" Casts of this species show the posterior lateral teeth of the hinge 

"to present the usual characters of the genus; while in one specimen the 

posterior cardinal tooth of the right valve can be seen to be strong and 

deeply bifid. Another specimen shows the middle cardinal tooth of the 

left valve to be strong, prominent, broadly trigonoid conical, and slightly 

curved upward at the-end, as in the type-species, and the posterior cardinal to be narrow and arcuate; the oblique, trigonal pit for the middle 

cardinal tooth of the other valve occupying the space between the two. 

None of the specimens show the anterior cardinal tooth of either valve; 

but enough of the hinge and other characters can be determined to remove all doubt in regard to its being a true typical Veniella and not a 

Venilicardia.

" Generally, the internal casts of this species retain no traces of the
106 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL. 106.

surface-markings, but sometimes they present faint remains of concentric undulations. The posterior umbonal ridges, however, are always 

strongly defined, and angular even on internal casts. Some large specimens have, in casts, a strong, obtuse ridge near the dorsal margin of 

each valve, apparently bounding a kind of broad lanceolate escutcheon, 

the middle and deeper part of which is occupied by the rather narrow 

ligament. °

" Young specimens of this shell present much the general outline of 

small individuals of Veniella (Venilicardia obtruncata] Stoliczka, (Palseont. Ind., in, Pl.'viir, Figs. 7 and 7a, &); but they have the umbonal 

ridge of each valve much more deeply defined, while the hinge characters of the two shells are altogether different. Of course, if Dr. Morton's name Venilia should be retained for this genus, the name of this 

species would become Venilia goniopliora.

" Locality and position. Missouri river, near Fort Benton; Fort Benton group of the Cretaceous."

Dr. White reports the species from u southeast of Paria, Utah." 1

There is some reason for doubting that this is really distinct from 

Veniella mortohi.

VENERIDyE. 

Genus TAPES Megerle v. Miihlfeldt.

TAPES CYRIMERIFORMIS tf. sp.

PI. xxiv, Figs. 1-6. ,

Shell of medium size, equivalve, moderately convex, subcircular in 

outline; beaks small, approximate, situated a little in advance of the 

middle; Cardinal margin sloping with nearly equal gentle convexity 

in both directions from the beaks; anterior end broadly and regularly 

rounded; posterior end slightly subangular above and rounded below; 

basal margin forming a regular gentle curve. Surface marked by fine 

lines of growth. There is no distinctly defined lunule. The ligament, 

which is preserved on some specimens, is relatively large and prominent.

Hinge of right valve with three strong, divergent, cardinal teeth, of 

which the posterior is deeply bifid and the other two. are smaller and 

more approximate. In the left valve, which also has three teeth, the 

anterior tooth is very small, the middle one is larger and slightly bifid, 

and the posterior one is very long and oblique and situated near the 

outer margin of the hinge.

The muscular scars are large, ovate, not very strongly marked; pallial sinus deep, ascending and narrowly rounded at the extremity.

One of the type specimens measures 49min in length, 42nim in height, 

and 16mm in convexity of both valves united. The corresponding meas1 See TJ. S. Geog. anjl Geol. Stir. West 100th Meridian, vol. iv, p. 185.
STANTON.] VENERIDJE. 107

urements ot another specimen, that is .much more convex tlian any of 

the others, are: Length, 44mm ; height, 36mm ; convexity, 18mm. Other 

examples are somewhat larger than either of these.

This species would probably be included in Cyprimeria as extended 

and defined by Zittel in the Handbuch der Palceontologie, but it differs 

from the typical species of that genus in that it is equivalve, its valves 

are not twisted, and its pallial sinus is deep. The hinge resembles that 

of Cyprimeria in a general way, especially if the two anterior teeth of 

the right val^e be regarded as one bifid tooth. Venus faba Sow., which 

is apparently a closely related form showing precisely the same generic 

characters, has been referred by some authors to Cyprimeria, but Holzapfel 1 has recently regarded it as a Tapes, and after comparing the 

Colorado fossils with recent species of that genus the reference seems

to me a natural one.

Locality and position. In the Pugnellus sandstone on Williams 

creek, Muddy creek, and Poison canyon, Huerfano park, Colorado. 

Casts that are believed to belong to this species have been found in 

the "first ridge" at Coalville, Utah.

Genus LEGUMBN Conrad.

This genus was described in 1858 2 and the description was supplemented in 1860 3 after the hinge of both valves had been studied. The 

type is Legumen ellipticum, from the cretaceous beds near Ripley, Mississippi.

It has always referred to the Solenidse, but in form and in the details 

of the hinge it'agrees very closely with Tapes fragilis (d'Orb.), and I 

believe that it is congeneric with that species which is the type of Stoliczka's genus Baroda. If this proves to be true Baroda, being a later 

name, should be treated as a synonym.

In Tryon's Structural and Systematic Conchology, vol. in, p. 132, 

this genus is erroneously called Legumenaia Conrad.

LEGTJMEN, sp. 

PI. xxiv, Fig. 11.

In the Pugnellus sandstone in Poison canyon, Colorado, a single 

specimen was found that probably belongs to this genus. It is a cast 

of a left valve retaining a little of the shell near the dorsal margin, but 

it does not show the structure of the hinge nor the pallial line.

.In outline it is not very different from Baroda ivyomingensis Meek, 

from the upper portion,of the Montana formation, and it is still more 

nearly like the forms -from the Kipley beds on which Conrad founded 

his genus Legumen.

'Die Mollusken d. Aachener Kreide, II. Abtheil., i>. 105, PI. 13, Figs. 7-10, Palieoutographica, vol. 35. 

2 Jour. Acad. Nat. Sci. Phila., 2d ser., vol. ui, p. 325. 

8 Idem, vol. iv, p. 277.
108 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL. 106.

Genus CALLISTA Poll.

CALUSTA (DOSINIOPSIS?) ORBICULATA H. & M.

PL. xxiv, Figs. 9 and 10.

Cytlierca orMculata Hall and Meek, 1856, Mem. Am. Acad. Arts and Sci. n. s., vol v,

p. 382, PI. 1, Fig. 7.

Meretrix orMculata Meek and Hayden, 1860, Proc. Acad. Nat. Sci. Pliila., p. 185. 

Dione orMculata Meek, 1864, Sraithsonian Check List Invert. Foss. of N. A., p. 13. 

Callista (Dosiniopsis) orMculata Meek, 1876, U. S. Geol. Stir. Terr., vol. IX, p. 186, PI. 5,

Figs. 2 a-c.

Revised description:

" Shell thick, suborbicular; beak moderately elevated and near the 

anterior side; posterior margin regularly rounded; surface marked by 

fine, equal, concentric lines.

"Length, 1.08 inches; height, 1 inch; width, 0.66 inch.

" Our specimens of this species are merely internal casts, with portions of the shell attached. Like that first figured by Prof. Hall and 

the writer, they present no characters by which we can determine 

definitely its generic relations. Some of the specimens show the muscular impressions to be shallow and ovate in form; the.posterior impression being, as usual, broader than the anterior. The pallial line is 

provided with a triangular sinus, Avhich extends a little obliquely 

upward and forward, about two-thirds of the distance from its base 

toward the middle of the valves, its sides converging at an angle of 

about 125° to 130°.

11 Although some of our specimens present exactly the form of the 

figure above cited, the majority of them differ considerably, being more 

nearly transversely-ovate in outline, in consequence of the posterior 

Side being more extended and less broadly rounded. These may belong 

to a different species; but as they vary in this respect, and their muscular and pallial impressions, as well as the thickness of the shell, are 

exactly as in the more orbicular individuals, I do not think it advisable 

to separate them without being satisfied, from the comparison of better 

specimens, that they are distinct.

"Should these more nearly ovate specimens be identical with G. orUculata, as believed, the specimen first figured in the memoirs of the 

American Academy of Arts and Sciences, must give an incorrect idea 

of the general form of this species, since a majority of the specimens 

are much less broadly rounded posteriorly.

''Some varieties of this species, especially the broader forms, resemble 

somewhat the species C. Owenana, but they are usually less concave in 

outline just in advance of the beaks, and the pallial sinus is always 

different in form, as may be seen by the figures. Some of the varieties 

also resemble our G. Deweyi in form, as well as in the pallial sinus and 

muscular impressions, but it is evidently a much thicker shell, and often 

distinctly more gibbous.
8TANTON.1 VENERIDJE. ' 109

"Locality and position. Five miles below the mouth of James river, 

at the base of the Fort Bentoii group, or formation No. 2 of the Upper 

Missouri Cretaceous. It was from this same locality and position that 

the specimen first figured by Prof. Hall and the writer was obtained."

CALLISTA (APHBODINA 1?) TENTHS H. & M. 

PI. xxiv, Figs. 7 and 8.

Cytherea tennis Hall and Meek, 1856, Mem. Am. Acad. Arts and Sci., n. e., vol. v, p. 383,

PI. 1, Fig. 5.

Meretrix tennis Meek and Hayden, I860, Proc. Acad. Nat. Sci., Phila., p. 185. 

Dione ? tennis Meek, 1864, Smithsonian Check-List, Invert. Foss. of N. A., p. 13. 

Callisla (^hrodina?) tennis Meek, 1876, U. S. Geol. Sur. Terr., vol. ix, p. 188, PI. 5,

Figs. 1, a-d.

Eevised description:

" Shell thin, varying in form from subciroular to transversely ovate, 

rather gibbous at maturity. Anterior side rather short, obliquely subtruncate above, and abruptly rounded below; base forming a seiniovate curve, being a little more prominent before than behind the. middle ; posterior side narrowly rounded, or sub truncate; beaks moderV ately prominent, somewhat gibbous in old shells, incurved, contiguous, 

and placed nearly halfway between the middle and anterior side; lunule 

obovate, fiat, and not very distinctly defined. Surface marked by fine, 

crowded, concentric striae, and sometimes a few, obscure, parallel furrows near the border.

"Length of an adult shell (oval var.), 1 inch; height, 0.78 inch; convexity, 0.56 inch.

u None of our specimens expose the interior, but internal casts show 

that the muscular impressions are faintly marked and of a rather narrow oA^ate form, both before and behind. The pallial line is also seen 

to be provided with a broad, shallow sinus, having nearly the form of 

. an equilateral triangle. Little or nothing being known in regard to 

the teeth of its hinge, it is, like the last, only referred doubtfully to 

this group. By working carefully about the hinge, however, and grinding down some of the specimens, I have nearly satisfied myself that it 

has a small anterior lateral tooth as in Meretrix (= Cytherca} and Callista; and as the pallial sinus is distinctly triangular, as in some sections of the latter, I think there is not very much reason for doubting 

the propriety of placing' it,'at least provisionally, in the latter genus; 

though better specimens may show it to belong to some other group.

"Locality and position. South fork of Cheyenne river, near the base 

of the Black hills, in the Fort Union [Benton] group, or formation No. 2 

of the Upper Missouri Cretaceous. The specimens first described in the 

paper "cited at the head of this description were collected from the same 

formation on the Missouri river, 5 miles below the mouth of James river.
110 COLOEADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL. 106.

DONACID^.

t 

Genus DONAX Linnaeus.

DONAX CUNEATA n. Sp.

PL xxv, Fig. 1.

Shell transversely elongate-triangular, moderately thick, somewhat 

compressed, especially toward the front; anterior end very greatly produced, narrowly rounded at the extremity and slightly curved upward, 

the dorsal margin being gently concave and the base somewhat convex 

in outline; posterior e*nd abruptly truncate about at right angles to the 

longer axis of the shell; the truncate portion bordered by the sharp 

prominent vertical uinbonal ridge extending from the beak to the postero-basal angle; beak rather prominent, directed slightly forward, 

nearly or quite.terminal (at the posterior end).

Surface apparently smooth and the free margins not crenate within.

The hinge has not been exposed sufficiently for figuring, but its 

structure can be seen fairly well in the type, which is a right valve. 

There are two approximate cardinal teeth under the beak, and both 

the anterior and posterior lateral teeth are well developed, the former 

being elongate and located a considerable distance in front of the beak, 

while the latter is shorter and is near the cardinal teeth.

Length, 27I11IU ; height at posterior end, 16mm ; convexity of single 

valve at posterior end, 45""".

The type of this species is a right valve from which most of the shell 

has been eroded. A smaller sandstone cast from another locality and 

a higher horizon has the same outline and probably belongs to the same

species. With such limited aucl imperfect material it is of course

impossible to say positively whether the generic reference above given 

is correct, but the form and the internal features, so far as they are 

known, agree very well with some living species of Donax. If it really 

is a Donax it is one of the oldest known species. The oldest previously 

described American form that has been referred to the genus is D. lata 

Gabb, from the Tejon group of California. Stoliczka figures a specimen 

which he says seems to be a true Donax from the upper part of the Cretaceous of southern India. The same author states that other described 

Cretaceous species probably do not belong to this genus.

I do,not know any fossil form hithertp described with which this 

species need be compared.

From the species described below it differs in that its anterior end is 

proportionally longer, more slender, and more narrowly rounded in front, 

while its posterior end is much shorter.

Locality and position. The type is from coal-bearing sandstone at 

Bear Biver city, Wyoming, where it is associated with Inoceramus 

labiatus, Pugnellus fwiformis, Cardium pauperGulum^ etc. The other
STANTON.] . DONACID2E, TELLINID^E. Ill

specimen above mentioned is from the " third ridge" of the section at 

Goalville, Utah, which is a considerably higher horizon and probably 

in the Montana formation.

DONAX? OBLONGA II. Sp.

PI. xxv, Fig. 2.

Shell rather large, moderately convex, transversely oblong, with the 

short posterior end obliquely truncate; dorsal and ventral margins 

nearly parallel; anterior end produced, broadly rounded at the extremity 

with the greatest convexity of the curve.above; posterior umbonal slope 

prominent and angular, varying considerably in obliquity, but.always 

more oblique than in I), cuneata; beak rather prominent, incurved. 

Surface and hinge unknown. The casts show a few distant concentric

furrows.

Length of the largest specimen, 45"im ; height, 28mm ; greatest convexity of single valve, 8 mm .

Besides the large specimen that is figured there are six other much 

smaller ones that were found associated with it and doubtless belong to 

the same species. They are all internal casts in sandstone, showing none 

of the generic features excepting the form, but they are apparently 

related to the preceding species, and are therefore referred to the same 

genus.

I dislike to describe and name such obscure fossils, but in the present 

case, as the form is very different from any of its associates, it can be 

easily identified if bjetter preserved examples are ever found, and meanwhile the species is just as useful for geological purposes as it would 

be if all its characteristics were known.

Locality and position. In the "second ridge" of the Cretaceous section at Coalville, Utah, which is approximately the same horizon from 

which the preceding species were obtained.

TELLINID^E. 

Genus TELLER A Linnaius. 

v TELLINA MODESTA Meek.

PI. xxv, Fig. 3.

Tellina modesta Meek, 1877, U. S. Geol. Expl. 40th Parallel, vol. iv, p. 157, PI. 15, Figs. 

4 and 5.

. Original description£*"" ^-^ J^'*''-" ~

"Shell rather small, transversely elongate-subelliptic, being twice as 

long as high, rather distinctly compressed; anterior margin narrowly 

rounded; base forming a long, semielliptic curve; posterior extremity 

more narrowly and less regularly rounded than the other, apparently 

slightly bent to the left; dorsal margin declining very slightly, with
112 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL. 106.

convex slopes, both in front and behind the beaks; beaks very nearly 

central and inconspicuous, being depressed and compressed. Surface 

of casts smooth, but probably on well-preserved shells marked with 

fine concentric striae. Hinge and interior unknown, with the exception 

of some appearances of lateral teeth seen in casts.- 

___"Length, 0.86 inch; height, 0.44 inch; convexity, 0.10 inch."

The name of this species was first used in a list of fossils from Coalville, Utah, published in the Ann. Eept. U. S. Geol. Sur. Terr, for 

1872, but it was not then described. All^the specimens yet found are 

casts in sandstone that show neither the natural surface nor the internal features. It does not resemble any known form in the Cretaceous 

of the interior region, but there is a closely related undescribed species 

in the Eipley beds of Texas, and when describing it Prof. Meek pointed 

out its resemblance to T. ashburneri which occurs in the Chico series of 

California.

Locality and position. Whitish Cretaceous sandstone on East Cany on 

creek, Wasatch range, Utah. The specimen figured is from the " second ridge," at Coalville, Utah.

TELLINA (PAL^OMCERA?) WHITEI n. sp. 

PL xxv, Figs. 4-7.

Shell of medium size, inequilateral, subovate, moderately convex; 

beaks rather broad and flat, situated behind the middle and directed 

backward; posterior end descending abruptly from the beak in abroad 

somewhat irregular curve to the base, where it is obscurely subangular; 

cardinal margin in front of the beaks, straight, descending with a more 

gentle declivity to the anterior end, which is regularly rounded and 

slightly narrower than tlie posterior end; base, nearly straight in the

middle, more strongly curved toward the ends. Surface marked by 

fine concentric striae and lines of growth. An obscure ridge extends 

from the umbonal region near the margin of the valve to the posterobasal angle, and a short distance in front of it the shell is slightly bent 

to the right. One of the specimens shows traces of a few faint impressed radiating lines near the posterior end.

The ligament is rather prominent and there is a deep lanceolate area 

in front of the beaks. The pallial sinus is broad and deep.

Length of the larger type specimen, 35"""; height, 25 mm ; convexity, 

of both valves united, 12mm . .

As neither of the two types shows the hinge the generic relations of 

this species are doubtful, but the features above described are deemed 

sufficient to warrant its assignment to the Tellinidse, and on account of 

its general resemblance to Tellina (Palceomcera) inconspicua Forbes as 

figured by Stoliczka1 it is provisionally placed in the same subgenus.

Locality and position. In the Pugnellus sandstone on Williams creek, 

Huerfaho park, Colorado.

1 Cret. Pelec. of S. India, pi. 4, figs. 6-8.
STAOTOH.] TELLINID2E. 113 

TELLINA *? SUBALATA Meek (sp.).

PI. xxv, Fig. 9.

Cyprimcra subalata Meolc, 1873, Ann. Kept. U. S. Geol. Sur. Terr, for 1872, p. 476. 

Cyprimeria? subalata Meek, 1877, U. S. Geol. Expl. 40th Parallel, vol. IV, Pt. 1, p. 158, PI. 

15, Fig. 7.

Revised description:

"Shell transversely broad-snbovate or subelliptic, strongly compressed 5 extremities rather narrowly and nearly equally rounded; 

basal margin forming a regular semielliptic curve, being most prominent along the middle, and rounding up gradually and equally into the 

anterior and posterior lateral margins; dorsal margin sloping from the 

beaks, the posterior slope being more convex in outline' than the anterior; beaks small, scarcely projecting above the hinge-margin, very 

nearly or exactly central, and almost entirely without obliquity. Surface apparently smooth, or only showing very fine, obscure, concentric 

striae. (Hinge and interior unknown.)

"Length, 1.22 inches; height, 0.90 inch; convexity of left valve, only 

about 0.12 inch."

The type specimen bears the label Tellina (Arcop.) subalata in Mr. 

Meek's handwriting, but after comparing it with Cyprimeria depressa 

Conrad he concluded that it belonged to the same genus on account of 

a resemblance in form. The additional material recently collected at 

Coalville, Utah, is in the form of casts, one of which retains impressions 

of two cardinal teeth, showing that it belongs to the Tellinidae rather 

than the Yeneridse.

Locality and position. The type is from whitish Cretaceous sandstone, East Canyon creek, Wasatch range, Utah, where it is associated with Trigonarca obliqua and other Colorado species. At Coalville it was found in the sandstone of the " third ridge," which is 

believed to belong to the Montana formation.

TELLINA H ISONEMA Meek. 

PI. xxv, Fig. 8.

Tellina f ? isonema Meek, 1877, U. S. Geol. Expl. 40th Parallel, vol. IV, pt. 1, p. 156, PI. 

15, Fig. 6.

Original description:

"Shell transverse, elliptic-subtrigonal in outline, compressed, and 

nearly or quite equilateral; anterior margin narrowly rounded; base 

forming a semi-elliptic curve; posterior end narrowly rounded or subangular at the termination of a slight, oblique flexure of the valves; 

dorsal margin sloping from the beaks to the extremities, with a moderately convex outline; beaks almost central, rather small, and projecting a little above the cardinal margin, incurved with scarcely any visible obliquity; hinge and interior unknown. Surface ornamented by 

Bull. 106 8
114 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL. 106.

fine, perfectly regular, concentric, thread-like lines, gradually becoming1 smaller and more crowded toward the umbones, on which they are 

nearly or quite obsolete.

"Length, 0.90 inch; height, 0.60 inch; convexity, about 0.20 inch." 

Prof. Meek explains that the species is known only in the form of 

sandstone casts that do not show the hinge nor any other internal characters and that its reference to Tellina is very doubtful. It seems to 

me more probable that it is a Mactra, but as I have not been able to 

demonstrate the character of the hinge it is left under the original 

name.

Locality and position. East Canyon creek, Wasatch range, Utah; 

sandstone of the "second ridge "at Coalville, Utah. A cast that 

seems to belong to this species was found in the " third ridge " of the 

same section.

Genus SILTQUA Megerle v. Miihlfeldt.

SlLIQUA HUERFANENSIS n. Sp.

PL xxv, Figs. 10 and 11.

Shell long and narrow, inequilateral, somewhat compressed, gaping 

at both ends; dorsal margin very slightly convex; basal margin nearly" 

straight or slightly sinuous in the middle; both ends broadly rounded, 

but the anterior end slightly narrower than the posterior; beaks very 

small and inconspicuous, located a little in advance of the middle. 

Substance of the shell thin, marked on the surface by very faint lines 

of growth and by a few larger irregularly arranged concentric undulations.

Pallial sinus broad, rounded and rather deep. Muscular impressions near the cardinal margin, well marked on adult shells; the anterior one elongate and narrow, just in front of the beak; posterior impression ovate, about half way between the beak and the posterior end. 

An internal rib runs obliquely downward and forward from the beak, 

gradually becoming less prominent and ending about half way between 

the dorsal and ventral margins. The structure of the hinge has not 

been satisfactorily made out, but some of the casts show impressions 

of two or three very small cardinal teeth.

Length of medium- sized specimen, 58mm ; greatest height, 18mm ; convexity of the two valves united, about 9 mm.

In outline this shell is very similar to some recent species of Pharella, 

but the presence of the internal rib and the large size of the pallial 

sinus will not allow a reference to that genus, and on account of these 

features it is provisionally referred to Siliqua. I think that Pharella ? 

dakotensis M. & H., from the Dakota formation near the mouth of Big
STAOTON.] SOLENIDJE. 115

Sioux river, is closely related to this species, though probably dis-^ 

tinct.

Locality and position. In the Pugnellus sandstone on Williams 

creek and other places in Huerfano park, Colorado, where about forty 

specimens were collected, and near the base of the cretaceous section at 

Coalville, Utah.

Genus PHARELLA Gray. 

PHARELLA? PEALEI Meek.

PI. xxv, Figs. 12 and 13. 

Pliarella? pealei Meek, 1873, Ann. Kept. U. S. Geol. Sur. Terr, for 1872, p, 496; 

White, 1880, idem for 1878, p. 21, PI. 11, Figs. 6a, ft.

Original description:

" Shell elongate-oblong, or subrhombic, the length being about twice 

and a half the height, rather compressed; anterior margin slightly 

sinuous just in advance of the beaks above, and somewhat narrowly 

rounded below this faint sinuosity; posterior margin truncated, with a 

convex outline, very obliquely backward and downward, from the posterior extremity of the hinge to the prominent and very narrowly rounded 

or angular posterior basal extremity; hinge-line proper apparently 

comparatively short, and not forming any angularity of outline at its 

connection with the sloping posterior dorsal margin; beaks rising a 

little above the hinge margin, but rather depressed and placed about 

one-fifth the entire length of the valves from the anterior margin; 

basal margin long, slightly sinuous along most of its length; posterior 

dorsal slopes rather prominently rounded from the beaks obliquely to 

the posterior basal extremity. Surface only showing obscure lines of 

growth. '

"Length, 1.20 inches; height, 0.48 inch; convexity, 0.28 inch.

"Knowing nothing of the hinge of this shell, I only refer it provisionally to Pharella. It does not seem to have had the extremities 

gaping as in that genus; but the specimen has evidently been accidentally compressed, and this may have given the valves the appearance 

of being closed. In general appearance it resembles Solen guerangeri 

d'Orbigny, which seems to belong to the genus Pharella. Our shell, 

however, evidently differs from d'Orbigny's specifically, at least, in not 

having the posterior margins of its valves near so abruptly truncated, 

but rounding and sloping forward gradually into the dorsal outline 

above. Possibly I should call it Modiola pealei.

"Locality and position. Missouri river, below Gallatin, Montana, 

Cretaceous."
116 COLOEADO FORMATION AND ITS INVERTEBRATE FAUNA. [Buix.106.

PHOLADOMYID^E.

Genus PHOLADOMYA Sowerby.

PHOLADOMYA PAPYRACEA M. & H.

PI. xxvi, Fig. 1.

PJioladomya papyracea Meet and Haydon, 1862, Proc. Acad..Nat. Sci. Phila., p. 27; 

Meek, 1876, U. S. Geol. Sur. Terr., vol. EX, p. 217, PL 5, Figs. 4a and 6.

Revised description:

" Shell under medium size, very thin and fragile, transversely subovate in outline, with length about once and a half the height, rather 

compressed, the greatest convexity being in the anterior and uinbonal 

regions; posteriorly cuneate and a'little gaping; outline of base regularly semiovate, its greatest prominence being a little in advance of 

the middle; anterior side short and rounded; posterior longer and more 

narrowly rounded; hinge margin straight, not inflected so as to form a 

denned false area, but subcarinate all along; beaks depressed, small, 

and incurved, located near the anterior end of the valves, though not 

terminal. Surface of each valve ornamented by about ten to twelve 

small radiating costee, which are crossed, and, as it were, cut into very 

small tubercles by numerous, very regular, sharply denned, and much 

more closely arranged concentric ribs and furrows, the markings being 

all well denned on the internal cast.

"Length about 1.16 inches; height, 0.76 inch; convexity, 0.55 inch.

"In a side view this species more nearly resembles P. tencra of Agassiz (particularly as illustrated by Fig. 16, PL 3a, of his Etud. Grit.) 

than any other form with which I luive compared it. It is decidedly 

more compressed, however, as well as more depressed, and may also

be at once distinguished from that species by having no traces of a 

false cardinal area, which is well defined in that species. The only 

good specimen of it that I have seen was found by Lieut. Mullanof the 

United States Topographical Engineers.

" Locality and position. Chippewa point, near Fort Benton, on the 

upper Missouri, in the Fort Benton group of the Cretaceous series of 

the Northwest."

Some specimens recently collected from the same horizon in northern 

Montana by Mr. "W. H. Weed are fully twice as large as the type.

PHOLADOMYA COLORADOENSIS n. sp. 

PL xxvi, Fig. 2.

Shell transversely elongate oval, depressed; anterior end regularly 

rounded from the beak to the base; basal margin forming an irregular 

broadly rounded curve with the greatest convexity in the posterior 

third; posterior end abruptly narrowed and subangular; beaks rather
STANTON.] ANATINHXaE. 117

broad, approximate, projecting considerably beyond the hinge line and 

situated about one-fifth the total length of the shell behind the anterior 

end. Surface marked by 25 to 28 narrow, angular, radiating costae, some 

of which occasionally bifurcate. The interspaces are not quite equal, 

even on the middle portions of the valve, and they become much broader 

toward the anterior and posterior ends.

Length, 46ram ; height, 29mm ; convexity of a single valve, about 10mra . 

Broken specimens in the collection show that the species sometimes 

reached dimensions one-half greater than those given.

This species seems to be closely related to P. breweri Gabb, from the 

Cretaceous of California, and it is also quite similar to P. subventricosa 

M. & H., from the Fox Hills beds at the mouth of Judith river. From 

the former it differs in the more elongate form, more contracted posterior end, and less regular costae.

Pholadomya subventricosa is known only by a single distorted specimen, but it seems to be more ventricose, and the posterior end is broader 

and the beaks are nearer the anterior end than in our species.

Locality and position. Williams creek, Huerfano county, Colorado, 

in the Pugnellus sandstone.

ANATINID^E.

i Genus ANATHsTA Lamarck.

ANATINA LINEATA n. sp.

PI. xxvi, Figs. 3 and 4.

Shell of medium size, transversely subelliptical or elongate ovate in 

outline, inequilateral; anterior end produced, broadly and regularly 

pounded; posterior end short, gaping, abruptly contracted, and more 

narrowly rounded; dorsal margin concave immediately behind the 

beaks and gently con vex in front; basal margin forming a broad curve; 

beaks small, approximate, fissured, with an oblique internal rib behind 

the fissure. The valves are slightly flattened in the middle, so that the 

greatest convexity is in advance of that region. Surface marked by 

strong concentric undulations that become obsolete on the posterior 

third of the shell, and by more numerous fine concentric lines covering 

the whole valve. The best preserved impression of the surface shows 

also two to three faint radiating lines on the unibonal region.

Length of a large specimen (anterior portion restored from other examples), about 70mm ; height, 44mm ; convexity of both valves united 

16mm .

Anatina sulcatina Shumard? as figured by Whiteavesl and by White2, 

is very closely related to the form here described. Our species has 

somewhat more prominent beaks and it lacks the well-defined furrow 

that extends from the beak to the base in A. sulcatina.

iMesozoic Fossils, vol. i, PI. 17, Fig. 5. * Bull. U. S: Geol. Sur. No. 51, PI. 6, Fig. 1.
118 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA.

Locality and position. In the Pugnellus sandstone on Williams 

creek and in Poison canyon, Huerfano county, Colorado. At Coalville, Utah, casts that are believed to belong to the same species were 

found in the sandstone of the " first ridge," and also at a much higher 

horizon in the " third ridge" of the same section.

Genus LIOP1STHA Meek.

LlOPISTHA (PSILOMYA) MEEKI White.

PI. xxvi, Figs. 5-7.

Llopistha (Psilomya) Meeki Wliite, 1874, Expl. and Sur. West 100th Merid., Prelim. 

Rept. Invert. Fossils, p. 26; 1876, U. S. Geog. and Geol. Sur. West 100th Meridian, 

vol. iv, p. 186, PI. 18, Fig. 14o~d.

Eevised description:

"Shell short, much inflated; umbones large, elevated5 beaks small, 

strongly curved inward and downward, and very slightly turned forward; posterior portion moderately produced, somewhat compressed 

laterally; free margins forming a regular but unequally convex curve, 

the greatest convexity of which is in front and the least along the base; 

upper portion of the posterior border obliquely truncated, so that the 

greatest posterior extension of the shell is a little below the hinge extremity.

" Surface having a smooth aspect, but it is marked by fine concentric 

lines of growth. Under a lens, very fine, obscure, radiating striae are 

seen upon the surface of a little more than the anterior half of the 

shell; and upon the remainder of the surface, except a small space adjoining the posterior cardinal border, there are small, somewhat distant, 

radiating striae, easily seen by the unassisted eye. Upon these striae, 

both the distinct and the obscure, the lens shows numerous minute 

punctures, placed at irregular intervals, which are the bases of minute, 

short, blunt spines, or which mark the places from which the spines 

have been removed.

"Length, 25min ; height, from base to umbo, 20mm ; greatest thickness, 

both valves together, 16ram.

"This shell seems to be more nearly related to L.globulosa( Poromya 

globulosa Forbes) than to any other described species. Compared with 

that species, as figured and described by Stoliczka, 1 ours differs in being less globular, in having the umbones more elevated, and in the more 

distinct radiating strise upon the posterior half of each valve."

Locality and position. The types come from southeast of Paria, Utah. 

In the Upper Kanab valley, which is not far from the typical locality, 

it occurs about 350 feet above the base of the Cretaceous section, associated with characteristic species of the Colorado formation.

 Cretaceous Fauna of Southern India, voL m, p. 47, PI. in, Fig. 8, and PI. XVI, Fig. 16.
6TANTON.] ANATINUm 119

LlOPISTHA (PSILOMYA) CONCENTRICA n. Sp*

PL xxvi, Figs. 8-10.

Shell of medium size, very thin, transversely ovate in outline, motU 

- erately convex; anterior and basal margins forming a continuous but 

unequally convex curve5 posterior end subangular and compressed j 

dorsal margin behind the beak, straight, slightly descending, abruptly 

deflected so as to form a distinct false area which bears fine transverse 

striae and is separated from the body of the shell by a narrow furrow 

running from the beak to the angular posterior end; beaks prominent) 

ventricose, incurved, and but slightly oblique, situated a little in advance of the middle. Surface marked by lines of growth and regular 

concentric undulations that are about lmm apart on the body of the 

shell, but are more closely arranged and more prominent near the

beaks.

Length of one of the largest specimens, 27mm ; height, 19mm ; convexity of a single valve, 8mm. _/

This species has very nearly the size and shape of L. meeJci. It is

slightly more elongate, however, and its surface ornamentation is

entirely different. The Survey collections contain more than a dozen

\ of each of these species, and the differences seem to be constant. The

' Utah species, L. meeki, never has the concentric undulations, and

always shows more or less radiating striae, while in L. concentrica the

reverse of this is true.

Locality and position. In the Pugnellus sandstone on Williams creek 

and in Poison canyon, Huerfano park, Colorado, and at about the same 

horizon on the Arkansas river, 20 miles above Pueblo, Colo.

NOTE. Since the ahove description was written ahout 25 additional specimens of Liopistha meeki 

have been collected in southern Utah, and among them is one marked with distinct radiating stria) 

and with concentric undulations almost as strong as in L. concentrica. Possibly the latter should be 

regarded as only an extreme variety of L. meeki, though the two forms are easily distinguishable.,

LIOPISTHA (PSILOMYA) ELONGATA n. sp. 

PL xxvi, Figs. 11 and 12.

Shell rather large for this genus, inequilateral, transversely elongate, 

moderately convex in the umbonal region, and compressed posteriorly; 

dorsal margin behind the beak, straight, and inflected so as to form a 

narrow false area; anterior margin forming a regular curve from the 

beak to the ventral margin, which is but slightly curved and almost 

^ parallel with the dorsal margin; posterior end subtruncate above and 

narrowly rounded into the base below; beaks prominent, ventricose, 

incurved, and approximate, situated about half-way between the middle 

and the anterior end. Surface marked by lines of growth and obscure 

concentric undulations that are most prominent on the umbonal region, 

and are as distinct on the casts as on the surface.

Length, 37'nm ; height, 27mm j convexity of a single valve, 9mm.
120 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL. 106.

. Externally this species has a close resemblance to certain forms of 

Pleuromya, and I was inclined to refer it to that genus, although it is" 

not reported as occurring in beds later than the Lower Cretaceous. On 

further examination a part of the hinge of a left valve was exposed, 

revealing a prominent conical tooth under the beak. So far as it is 

known, therefore, the hinge is like that of Liopistlia. The surface is 

not well enough preserved to show whether it was marked by the obscure 

radiating lines of granules or minute spines that usually appear on 

species of the Psilomya section of this genus, but this feature seems to 

be wanting in Liopistlia (Panopcea) frequens Zittel, a species from the 

Gosau beds that is very closely related to ours. Another species, 

described above under the name Liopistlia (Psilomya) concentrica, has 

very nearly the same surface ornamentation as L. elongata, but its 

form is more nearly like that of the typical species of the genus. It is 

worthy of remark that the three species herein described are the only 

American ones that have been referred to the subgenus Psilomya, and 

they all come from approximately the same horizon.

Locality and position. Upper Kanab valley, Utah, from concretions 

in shale about 350 feet above the base of the Cretaceous section.

MACTRID^E.

Genus MACTRA Linnaeus,

MACTRA (CYMBOPHORA?) UTAHENSIS Meek.

Plate xxvn, Figs. 16 and 17.

Mactra (Cympholora) utahensis Meek, 1877, U. S. Geol. Expl. 40th Parallel, vol. iv, 

Pt. 1, p. 155, PI. 15, Figs. 9, 9o, 9&.

" Shell subovate, moderately convex; anterior margin rounded; posterior margin narrower, and rather abruptly rounded, or sometimes apparently slightly truncated, being most prominent below; basal margin forming a semielliptic or semiovate curve, being sometimes more 

prominent anteriorly; dorsal outline sloping from the beaks toward the 

extremities; beaks moderately prominent, very nearly central, and incurved with little obliquity; umbonal slopes merely rounded, and not 

terminating in a flexure of the posterior basal margin. Surface apparently merely marked with fine, obscure, irregular lines of growth. 

Hinge merely known to possess linear anterior and posterior lateral 

teeth. Ligament and internal characters unknown. , 3 . v ^^ y f>r . ,*;-!,; ; . . ,» 4 . ^, *., i»~ * IT

"Length,-1-.35 inches; height, 0.904neh; convexity, about OzSO^ineh.

"The specimens of this shell in the collection agree so nearly with a 

form described by the writer in connection with Dr. Hayden, from the 

Upper Cretaceous beds on Deer Creek, near the North Platte, under 

the name Tellina nitidula, that I was at one time inclined to think 

they might belong to a variety of that species. Still, as they are merely 

j giving but a limited knowledge of the hinge, and showing nothing
STANTON.] MACTRID-E. 121

of the internal characters, it is much more probable that they ar.e 

really very distinct. So far as regards their form and general appearance, they seem only to differ in having the anterior side rather more 

produced and sometimes wider.

"From this general resemblance, however, I have, in the absence of 

any knowledge of the nature of its cardinal teeth or pallial line, ventured to refer it provisionally to the same section of the Mactra group 

to which Tellina nitidula is now Relieved to belong, that is, to Cymbophora Gabb. I should have been inclined to refer it to Macoma or 

Gastrana were it not for the impressions of lateral teeth seen before 

and behind the beaks in the casts.

ll Locality and position. Whitish Cretaceous sandstone, East Canyon 

creek, Wasatch range, and near Coalville, Utah."

At Coalville this is one of the most abundant species in the strata 

below the principal coal bed, but they are all in the same state of preservation as the types. At first I was inclined to doubt whether the 

two forms represented by Meek's figures are really the same species, 

but after comparing a large series I am unable to find any constant 

differences by which they may be separated. Several specimens of the 

equilateral form show impressions of cardinal teeth like those of 

Mactra.

MACTRA EMMONSI Meek. 

PI. xxvii, Figs. 9-1.3.

Mactra f emmonui Meek, 1877, U. S. Geol. Expl. 40th Parallel, vol. iv, Pt. 1, p. 153, 

PI. 15, Fig. 8.

" Shell small, oval-subtrigonal, rather compressed, longer than high, 

nearly or quite equilateral, or with anterior side slightly longer than 

the other; basal margin forming a semielliptic curve; anterior margin narrowly rounded below the middle; posterior margin somewhat 

broader, most prominent and abruptly rounded or obtusely subangular 

below, and very faintly subtruncated obliquely above; dorsal margin 

sloping before and behind the beaks, the anterior slope being greater, 

with a concave outline; beaks nearly central, or sometimes placed a 

little behind the middle, rather depressed, and incurved with very slight 

obliquity; posterior umbonal slope very obscurely angular from the 

beaks to the posterior basal extremity. Surface only marked by fine 

obscure lines of growth. (Hinge and other internal characters unknown.)

"Length, 0.45 inch; height, 0.30 inch; convexity, 0.17 inch. Some 

specimens of apparently the same species are nearly double the size of 

that from which the above measurements were taken, and some of the 

smaller ones are proportionally a little shorter."

The figured type is a small sandstone cast somewhat distorted by 

pressure, and with the beak partially concealed in the matrix, so that 

it was drawn less prominent and more obtuse than it really is. It was
122 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BOLL. 108,

collected in the Cretaceous sandstone on East Canyon creek, Utah, 

where it is associated with Cardium pauperculum and other characteristic species of the Colorado fauna. Some much larger casts from about 

the same horizon, the first ridge in the Coalville section, are believed 

to belong to the same species, because of their close agreement in form, 

when allowance is made for the slight distortion of the type. One of 

these larger specimens is figured.

In the Pugnellus sandstone of Huerfano park, Colorado, one of the 

more abundant species is a small Mactra that in size and form is very 

like the above-mentioned Coalville specimens, and I think it best to 

describe and figure it under the same name, although one can never be 

certain that a well preserved shell, showing the surface characters, belongs to the same species with an imperfect internal cast from a distant 

locality.

The description of the form as above given serves very well for tlie Colorado examples, excepting that the most of them are proportionally more 

convex and many are not quite so elongate anteriorly. There is a large 

distinct lunule, lanceolate in form, bordered by an impressed line that 

extends from the beak to the extreme anterior end. Behind the angulation of the posterior umbonal slope there are one or two other faint 

radiating lines, the posterior of which forms the boundary of the escutcheon. Both the lunule and the escutcheon are marked by regular, distinct concentric lines. The remainder of the surface bears only lines of 

growth that are very faint and closely arranged, excepting toward the 

ventral border of adult specimens, where they become nearly equal in 

size to those on the lunule.

The hinge structure, so far as seen, is that of a Mactra; there is a cartilage pit, in front of which is an A-sh&ped tooth, and the lateral teeth 

are well developed. The pallial sinus is short and rounded.

This species has some resemblance to small examples of Mactra warrenana, which occurs in the upper portion of the Montana formation, 

but M. emmonsi is a more depressed form with a smoother surface and 

slight differences in outline, which are regarded of specific importance, 

especially when considered in connection with the difference in size and 

in stratigraphic position.

MACTRA, HUERFANENSIS n. sp.

PL xxvn, Figs. 14 and 15.

Shell thin, depressed, subelliptical, nearly equilateral; anterior border regularly and rather narrowly rounded; posterior .border forming 

a slightly convex regular slope from the beak to the subangular posterior end; base forming a broad regular curve; beaks small, projecting 

slightly beyond the cardinal border. Surface smooth, marked only by 

faint lines of growth.

This species varies considerably in length and in convexity. The 

specimens selected for figuring, representing the extremes of variation,
8TAOTON.] MYID^E. 123

having the following dimensions, respectively : Length, 30 and 38"""; 

height, 21 and 22 mm ; convexity (of single valve), 5 and 4 mm.

The left valve has a medium-sized cartilage pit with a A-shaped 

cardinal tooth in front of it. Some of the casts show impressions of small 

lateral teeth. The anterior muscular impression is ovate or subcircular, 

the posterior, elongate ovate. Pallial sinus rather broad, rounded at the 

extremity, and horizontal. The structure of the hinge is determined 

from internal casts that do not show all the 'features clearly, so that it 

is impossible to say whether the species is a Mactra or some other 

allied genus.

I was at first inclined to identify these fossils with Tellina ? isonema 

which they closely resemble in general form. They differ from that 

species, however, in that their surface is much smoother, lacking the 

regular concentric lines and also the angular posterior umbonal slope.

Locality and position. In the Pugnellus sandstone at many localities 

in Huerfano* park, Colorado.

Genus COBBULA Brugui6re.

. DOEBULA SUBTRIGONALIS M. & H.

PI. xxvn, Figs. 7 and 8.

Corbula suMrigonalis Meek and Hayden, 1856, Proc. Acad. Nat. Sci. Phila., p. 116.

Corbula perundata Meek and Hayden, ibid.

Corbicula orassaUlliformis Meek, 1871, Ann. Kept. U. S. Geol. Sur. Terr, for 1870, p.

315.

Corbula tropidopliora Meek, 1873, idem for 1872, p. 514. 

Corbula subtrigonalia White, 1879, idem for 1877, p. 170 ; 1880, idem for 1878, p. 80,

PI. 25, Figs. 6a-f ; 1883, 3d Ann. Kept. U. S. Geol. Sur., p. 442, PI. 19, Figs.

10-13. 

Compare Coi'bula perangulala WMteaves, 1885, Cont. to Can. Palseont., vol. I, p. 9,

PI. 1, Fig'. 5a, b, PI. 2, Fig. 1.

Shell large, transversely elongate- triangular; moderately convex, subequivalve, the right valve beiug slightly longer and more convex than 

the other; anterior end short, obliquely subtruncate above, regularly 

rounded below to join the ventral margin, which forms a regular, 

gently convex curve; posterior end narrow, greatly produced, subangular at the extremity; posterior dorsal margin straight or very slightly 

convex, forming approximately a right angle with the truncate anterior 

end; beaks prominent, incurved; posterior umbonal slope very prominent and angular in the left valve, more rounded in the right. A 

broad area immediately in front of the umbonal ridge is flattened, while 

the portion of the shell between it and the dorsal margin is abruptly 

deflected. Surface ornamented by fine lines of growth and a few larger 

concentric ridges.

Length of a large specimen, 33 mm ; height, 21 mm ; convexity of a single 

^ left valve, 7 """.

The specimens here described were collected from coal-bearing sand-
124 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL. 1 06.

stone of the Colorado formation at Bear Eiver city, Wyoming (No. 12 

of Meek's Sulphur creek section), where they are associated in the same 

layer with Inoceramus labiatus, Cardium pauperculum, Pugnellus fusiformis, etc. After comparing them with the types of all the forms that 

are now regarded as varieties of Corbula subtrigonalis I am unable to 

find any reason for their separation, excepting that some of them *re 

larger than any other known specimens of G. subtrigonalis^ and they 

come from a much lower horizon. The types all came from strata 

that have been referred to the Laramie, C. subtrigonalis and C. perundata from the mouth of Judith river, C. tropidopliora and Corbiculaf 

crassatelliformis from the Bitter creek series of southern Wyoming. It 

should be stated that some examples in the Bear Eiver city collections 

agree perfectly with the varieties described as C. perundata and C. 

crassatelliformis. Whiteaves reports the occurrence of the species in 

the Belly Eiver series, which is supposed to hold the position between 

the Colorado and Montana formations, and I have found it atCoarVille, 

Utah, in the "third ridge," above the Carleton coal bed, which is 

referred to the Montana formation. The species therefore seems to 

range through nearly all of the Upper Cretaceous, from the Colorado 

to the Laramie inclusive, and from purely marine to brackish water 

beds. The well-known fact that recent marine representatives of the 

genus are not essentially different from those inhabiting the almost 

fresh waters of estuaries and the mouths of rivers makes it less sur-

*

prising that in the course of time a species should pass from one of 

these kinds of habitat to the other without material change.

CORBULA NEMATOPHORA Meek. 

PI. xxvn, Figs. 3 and 4.

Corbula n&matophora Meek, 1873, Ann. Rept. U. S. Geol. Sur. Terr, for 1872, p. 496; 

White, 1876, U. S. Geog. and Geol. Sur. West 100th Meridian, vol. iv, p. 188, PI. 17, 

Fig. 7; 1879, Ann. Rept. U. S. Geol. Sur. Terr, for 1877, p. 290, PI. 3, Figs.

Original description:

" Shell of about medium size, ovate-subtrigonal, nearly equivalve 

and moderately convex, with height equaling two- thirds the length; 

anterior outline rounded; base semiovate; posterior extremity somewhat produced and subangular or minutely truncated in outline below; 

dorsal outline sloping from the beaks, the anterior slope being more 

abrupt and slightly concave in outline above, and the posterior longer 

and nearly straight, with a greater obliquity; posterior umbonal slopes 

more or less angular in each valve from the beak to the posterior basal 

extremity; beaks rather prominent and placed about one-third the 

length of the valves from the front. Surface ornamented by small, 

regular, concentric ridges, or strong lines and furrows, both of which 

; are more distinct on the right valve than on the left, where they are

I sometimes obsolete.

\
BTANTON.] PHOLADID^E. 125

"Length of largest specimen seen, 0.50 inch; height, 0.32 inch; convexity, 0.25 inch."

Prof. Meek noted the close resemblance of this species to certain 

Laramie forms that are now regarded as belonging to Corlula subtrigonalis, and it may be that they are identical. It often happens that 

very qlosely related forms of this genus are found at greatly separated 

horizons, and for this reason, though a great many fossil species have 

been named, they can seldom be used with any certainty in correlating 

strata.

Locality and position. The types came from coal-bearing Cretaceous 

beds near Cedar City, Utah, apparently equivalent with the lower part 

of the Coalville section. The species is common beneath the main coal 

bed at Coalville, Utah, and in the " third ridge" of the same section I 

have collected specimens that seem to belong to it.

CORBULA KANABENSIS n. Sp. 

PL xxvii, Figs. 5 and 6.

Shell small, ventricose, subequivalve, equilateral, transversely ovate 

in outline; front end broadly rounded, forming a regular curve from 

the beak to the base; posterior end abruptly contracted and angular; 

beaks large, prominent, approximate; posterior uinbpnal slope subcarinate; basal margin usually thickened, and inflected so as to form 

a flattened band. Surface bearing fine regular concentric lines.

Length of a medium-sized specimen, lO1? ; height, 7mm ; convexity 

of both valves united, 5mm.

Corlula traslci, from the Chico group of California as figured by 

Gabb l and by Whiteaves,2 is very much like this species, and direct 

comparison of specimens may show that they are identical, but judging from the figures and description 0. traslci is more inequivalve 

and less regularly convex, and it lacks the angular umbonal slope and 

the thickening and deflection of the ventral border.

Locality and position. About 350 feet above the base of the Cretaceous section in Upper Kanab valley, southern Utah.

PHOLADID^E. 

Genus PAEAPHOLAS Conrad.

PARAPHOLAS SPHENOIDEUS White. 

PI. xxvn, Figs. 1 and 2.

Turnus sphenoideus White, 1876, Geol. Uinta Mts., p. 117.

Parapholas sph&noideus White, 1879, Ann. Kept. U. S. Geol. Sur. for 1877, p. 300, PI. 5, 

Figs. la-d.

Revised description:

"Shell elongate, cuneate, inflated in front, narrowed and laterally 

compressed behind; beaks anterior, incurved, adjacent; dorsal margins

»Pal8Bont., California, vol. 1, PI. 22, Tig. 121. *Mesozoic Foss., vol. 1, PI. 17, Fig. 3.
126 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL. 106.

of the valves straight and sloping from the beats to the posterior end, 

capped or connected by a slender styliform, plain accessory plate; posterior extremity small, truncated, or narrowly rounded; basal margins 

nearly straight, connected by a ventral accessory plate similar to the 

dorsal one, except that it is shorter, broadest behind, but coming to a 

slender point in front about midlength of the shell, longitudinally divided 

by a linear groove; front regularly rounded, both vertically and laterally; anterior gape consisting of a narrow, vertical slit, which occupies 

the middle of a somewhat prominent projection at the antero-basal portion of the shell, which projection has the shape of a Norman shield, as 

seen by front view when both valves are in their natural position, and 

which seems to have been occupied by a much wider gape in the younger 

than in the adult condition of the shell; both umbonal grooves distinct, both upon the outer surface and upon that of the stony cast; 

anterior grooves broader and deeper than the other, but both are 

slender; besides the two umbonal grooves there is another somewhat 

broader groove or furrow, extending with a broad, downward curve 

from the posterior side of the beak to the posterior end of the shell. 

This groove, like the others, is distinctly traceable upon the outer surface, but is more distinctly seen upon the stony cast.

"A broad, subcircular, cake-like umbonal accessory valve covers the 

beaks and the space between them, the valve being divided by a suture 

into two nearly semicircular pieces so neatly that it is hardly perceptible until the valves are slightly displaced. The margins of the principal 

valves between the beaks and the Norman shield-shaped projection are 

narrowly but abruptly everted, which, with the beaks above and the 

borders of the projection below, bound a distinctly hollowed space on 

each side and below each beak. Besides the grooves before mentioned, 

the surface is marked by fine concentric, distinctly raised lines on each

side of the shell, but they are less distinct upon the surface of the 

Norman shield-shaped projection than elsewhere. Between the posterior grooves or furrow before mentioned as ending at the posterior 

margin of the shell and the dorsal margin, the surface is occupied by 

strong, irregular scales and laminae that were successively left as the 

shell increased in size.

" Length, 13mm ; greatest height, 7mm ; breadth at front, 6 ."

For extended comments on the generic relationship of this species, 

see Dr. White's remarks in the second work above referred to.

Comparison of this species with Parapholas californica, the type of 

the genus, leaves little room for doubt that they are congeneric, but it 

seems to me that it is still an open question whether Parapholas is 

really distinct from Martesia.

Locality and position. Upper Kanab valley, Utah, and near the base 

of the Coalville section. Specimens from the latter place are mentioned by Meek1 as "Martesia (undetermined sp.)."

'Ann. Rept. TJ. S. Geol. Sqr. Terr, for 1872, p. 476.
8TANTON.] NERITID2E. 127

PABAPHOLAS? sp.

A bit of fossil wood collected in the Pugnellus sandstone of Poison 

canyon, Colorado, contained several short tubes of a boring mollusk 

that may belong to this genus. The large end of the tube is rounded 

and it tapers rapidly toward the posterior end. It seems to be a much 

shorter species than Parapliolas splienoideus.

GASTROPODA.

NERITID^E.

Genus NEBITINA Lamarck.

NEEITINA PISUM Meek.

PI. xxvm, Figs. 1-3.

Neritina (Neritella) pisum and N. pisiformis Meek, 1873, Ann. Kept. U. S. Gool. Sur.

Terr, for 1872, p. 500.

Neritina pisum White, 1879, idem for 1877, p. 308, PI. 7, Figs, lla-o. 

Neritina pisiformis White, 1880, idem for 1878, p. 26, PI. 12, Figs. 9o-o.

The original description of Neritina,pisum is as follows:

" Shell globose; spire much depressed; volutions about three, rapidly 

increasing in size, so that the last or body turn (which is a little depressed 

above) composes nearly the entire shell; inner lip broad, flattened, 

and smooth; aperture small and semicircular; surface nearly or quite 

smooth.

"Height, 0.22 inch; breadth, 0.26 inch."

On the same, page the following description of Neritina pisiformis is 

given:

"Shell small, subglobose, or obliquely rhombic, the height being 

slightly less than the oblique breadth; spire rather prominent for a 

species of this genus; volutions three to three and a half; convex; last 

one large, and forming most of the bulk of the shell; aperture subovate, 

considerably contracted by the flattened, moderately wide inner lip, 

which is nearly straight on its inner margin, and provided there with 

four small denticles, the upper one of which is largest. Surface smooth.

" Height, 0.30 inch; greatest oblique breadth, 0.32 inch.

" This little shell agrees sp nearly in size and form with the described 

species (N. pisum) that they may be readily confounded, as they are 

found with the aperture filled with rock. A fortunate fracture of one 

of the specimens exposed the inner edge of its flattened column ella, 

however, and thus enabled me to see that it is denticulated, and in this 

respect differs from Neritina pisum, which seems to be entirely without 

teeth. Further comparisons also show the two shells to differ in form, 

that under consideration having a more prominent spire and a more 

globose outline, being .less oblique."

On attempting to separate collections from the typical locality into
128 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL.IOO.

two species as above described, it was soon evident that they could not 

be separated by form alone because they vary in that respect, showing 

every gradation between the extremes represented by the types. Thetype of N". pisum was then studied more closely, and the rock was 

removed from the aperture, revealing the fact that the inner lip is denticulate as in N.pisiformis. Consequently the latter name must be regarded as a synonym of N. pisum.

Locality and position. Near the base of the Cretaceous section at 

Coalville, Utah.

KERITINA INCOMPTA White. 

PI. xxvin, Figs. 4 and 5.

Nerilina incompta White, 1879, Ann. Rept. U. S. Geol. Sur. Terr, for 1877, p. 308, PL 

7, Figs. a-c.

Original description:

" Shell transversely elongate when adult; spire depressed, abruptly 

convex, small, but rising perceptibly above the body- volution ; volutions three and a half or four, increasing rapidly in size, the last one 

comprising much the greater part of the shell, regularly convex or with 

a faint appearance of flattening upon the distal side of the last one; 

suture moderately distinct; aperture rather large, its outer border regularly rounded, proximal, and distal margins slightly convex and subparallel; outer lip thin-edged, inner lip moderately long, plain, slightly 

concave upon its face, not very broad, sloping inward. Surface marked 

by ordinary lines of growth.

" Length, in direction of the axis, 12mm ; breadth, across the aperture 

and body- volution, 17ram .

" This species resembles N. bannisteri Meek from the brackish- water

layers of the same formation at Coalville, Utah ; but it differs in the 

greater, although slight, elevation of the apex, the nearly straight, 

instead of curved, border of the inner lip, and its nonpolished surface." 

Locality and position. Valley of Sulphur creek, near Hilliard station, Wyoming, in strata that are now believed to belong to the Colorado formation.

(YELATELLA) PATELLIFORMIS Meek.

PI. xxvm, Figs. 6-10.

Neritina (Dostia f ) patelliformis Meek, 1873, Ann. Rept. U. S. Geol. Sur. Terr, for 1872,

p. 498. 

f Neritina (Velatella) carditoides White, 1876, U. S. Geog. and Geol. Sur. West 100th

Meridian, vol. iv, p. 189, PL 18, Fig. 7o-c. 

Neritina ( Velatella) patelliformisWhite, 1879, Arm, Rept. U. S. Geol. Sur. Terr, for 1877,

p. 309, PL 7, Figs. la-d. 

Neritina ( Velatella) patelliformis var. welerensis White, 1879, ibid. PL 7, Figs. 8a and ft.

Original description.

" Shell small, thick, oval, or subelliptic; nucleus nearly posterior 

and generally more or less elevated above the posterior margin, but
NERITID^. . 129

always lower than the middle portion of the dorsal region in front of it, 

directed obliquely backward, and in well-preserved specimens minutely 

subspiral at the immediate, more .or less oblique apex; inner lip very 

broad, or having the form of a thick, smooth, convex septum that extends forward more than half the length of the shell ; outer lip thickened, obtuse and smooth within; open part of the aperture small and 

transversely semicircular. Surface with moderately distinct lines of 

growth.

u Length of one of the largest specimens found, 0.62 inch; breadth, 

0.50 inch; height or convexity, 0.33 inch."

The variety weberensis White, which was found in the same layer with 

the typical form, was described as follows:

" Shell small, depressed, almost regularly elliptical in outline, nearly 

regularly convex above, and nearly flat or longitudinally slightly concave beneath; beak very small, apparently making about one volution, 

turned a little to the dextral side of the shell, resting upon the thickened posterior margin, but not projecting beyond it, the posterior margin being slightly refiexed so as to obscure the incurved apex; inner 

lip broad, smooth, flat, or concave longitudinally, and slightly convex 

laterally, apparently occupying more than half the under surface of the 

shell; outer lip moderately thin, smooth, or at least not crenulate. Surface marked by ordinary lines and undulations of growth, and upon the 

middle portion of the anterior half by five or six narrow, slightly raised, 

obscure, radiating ribs, with spaces between them a little wider than the 

ribs. In some cases there are also other obscure radiating lines upon 

the anterior flanks of the shell.

"Length, llmm ; breadth, 8 mm ; height, 5mm. Some examples in the 

collection are larger, but none of them quite equal in size the larger 

examples of the typical forms of the species.

u This variety, although perhaps connecting the typical forms with 

JV. (V.) carditoides Meek, differs from it in the number and character of 

its costse, the proportions of the shell, and its smaller size. At one 

time I thought, as did also Mr. Meek, that this variety might prove to 

be specifically distinct from the typical forms of N. (V.)patelliformis, 

but study of collections since made at the typical locality shows that 

intermediate forms exist, associated with this variety and the typical 

forms in the same layer."

It should be added that the inner lip of this species is slightly denticulate on the margin.

The name Velatella was proposed by Meek as a subgenus of Neritina 

to include this and a few other Cretaceous species. It was adopted by 

White, who gave a diagnosis of it in the Ann. Eept. U. S. Geol. Sur. of 

the Territories for 1878, p. 27. It seems to me to be scarcely distinct 

from Dostia, from which it differs "in its more nearly perfect bilateral 

symmetry and its minute apex."

Locality and position. Abundant in certain layers near the base of 

Bull. 106 9
130 COLOEADO FORMATION AND ITS INVERTEBRATE FAUNA. [BroL.108.

the Cretaceous section at Coalville, Utah, and in equivalent beds at Bear 

Biver city, Wyoming. Neritina carditoides, which is a closely related 

but probably distinct species, occurs at a much higher horizon in the 

" third ridge" of the same section.

TURRITELLID./E. 

Genus TUEEITELLA Lamarck.

TUKRITELLA WHITEI n. Sp.

PL xxvin, Figs. 12-16.

Turritella uvasana White, 1876, U. S. Gebg. and Geol. Sur. West 100th Meridian, vol.

iv, p. 195, PI. 18, Figs, lla and &. 

Not Turritella uvasana Conrad, 1856, Pacific Railroad Repts. vol. v., p. 321.

This species was first obtained from Cretaceous strata southeast of 

Paria, Utah, and was doubtfully referred to Turritella uvasana, a species of the Tejon formation of California.

Dr. White describes the Utah specimens as follows:

"Shell of ordinary size, elongate, slender 5 sides straight; volutions 

numerous, apparently reaching eighteen or twenty when full-grown; 

the sides of the volutions nearly straight or only slightly convex; 

suture broad, deeply impressed.

" Surface marked by numerous revolving raised lines, six or eight of 

which are moderately large, the smaller ones alternating with them. 

The larger lines are minutely nodose upon the larger volutions, and 

upon the last one they are even subspinulose.

u All the specimens of this species in the collection are more or less 

broken, but judging from the apical angle indicated by their sides, the 

largest must have been about 5£ centimeters long, and its last whorl 

about 13 millimeters in diameter."

Since the above description was published, Mr. C. D. Walcott has collected a number of good specimens at Upper Kanab, Utah, and the 

writer has more recently ob tained a great many from the Pugnellus sandstone of Huerfano park, Colorado. The study of this additional and better 

material has proved that it differs from Conrad's species in several particulars. The revolving lines of Turritella uvasana are not nodose, the 

apical angle is less than in our species, and the whorls are broader, so 

that there is a less number of volutions in a given length of specimens 

of the same size, and it is probable that the total number of volutions is 

less in the California species. Some young specimens of T. wMtei (or 

tips of old ones) from Upper Kanab have about twenty volutions in a ; 

length of a little over half an inch, and the diameter of the last whorl is' 

only 3 millimeters, or about the same as the upper end of the specimen 

represented by Fig. 12 on PI. xxvm. An individual of that size would,, 

therefore, have about thirty volutions when complete,
STANTON.] TURRITELLIDJE. 131

These differences are sufficient basis for the separation of the two 

forms, and the additional fact that one of them occurs near the base 

of the Upper Cretaceous, while the other is found at the very top of 

the Cretaceous or in the Eocene makes their separation still more 

reasonable.

It should be stated that the specimens from Colorado do not quite 

agree in ornamentation with those from Utah. The revolving lines are 

somewhat broader and fewer in number, usually not more than five or 

six prominent ones, and the intermediate fine thread-like lines are often 

obsolete. Perhaps such differences are of specific importance, but it 

seems to me more probable that they are only local variations of one 

species. If it should ever be found desirable to separate them the Utah 

form must be regarded as the type of Turritella whitei.

At a locality about 12 miles east of Walsenburg a number of specimens of the Colorado variety were found in a peculiar state of preservation that gives them a very different aspect. The shell is entirely 

replaced by calcite and the surface is eroded until there is hardly a 

trace of the-natural ornamentation remaining. The planing down of 

the rounded whorls has left irregular zigzag lines that are, in some 

cases at least, coincident with the angles of the calcite crystals. One 

of these is figured.

Locality and position. About 350 feet above the base of the Cretaceous section in Upper Kanab valley, Utah; in the Pugnellus sandstone of Huerfano park, Colorado, and at about the same or a little 

lower horizon in the Benton shales on the Arkansas river above Pueblo, 

at Eattlesnake butte, and other places in southern Colorado.

TURRITELLA MICRONEMA Meek.

PL xxix, Fig. 3.

Turritella (Aclis ?) micronema Meek, 1873, Ann. Rept. U. S. Geol. Sur. Torr. for 1872, p. 

504; White, 1879, idem for 1877, p. 316, PI. 9, Fig. 8a.

Original description:

" Shell small, terete or elongate-conical; volutions about nine, nearly 

flat, sometimes moderately convex, increasing gradually in size, last 

one rounded or obscurely subangular in the middle; suture linear to 

moderately distinct; aperture rhombic-ovate, angular above. Surface 

ornamented by fine, regular, rather crowded revolving lines, six or 

eight of which may be counted on each volution of the spire.

" Length of the largest specimen seen, 0.50 inch; breadth, 0.18 inch; 

angle of spire, about 19°, with slightly convex slopes. [Specimens 

since found at the original locality, and in the same layers, indicate a 

size nearly twice as great as this;]

"This may not be a Turritella^ the specimen not being in a condition 

to show the texture of the shell or to give a clear idea of its aperture 

and lip. It would be a rather small species for that genus, and if it
132 COLORADO FORMATION AND ITS INVERTEBEATE FAUNA. [BULL. 106.

possessed the delicacy of surface seen in those genera, it might per: 

haps with more propriety be referred to Aclis or Menestlio. The fractured lip in some of the specimens has somewhat the appearance of a 

slight angularity or very small notch at the base of the aperture, but 

this may be due to the manner in which it is broken; if not, it would 

seem to present affinities with the genus Mesalia. It will be readily 

distinguished from the species I described under the name T. spironema 

by its less attenuated form and finer and less distinct revolving lines. 

It is also not nearly so attenuated toward the upper part of the spire 

as that species.

" Locality and position. Coalville, Utah, from the Cretaceous below 

the heavy bed of coal mined at that place."

Genus GLAUCOMA Giebel.

GLAUCONIA COALVILLENSIS Meek (sp.).

PL xxvm, FIG. 11; PI. xxix3 Figs. 1 and 2.

Turritella coalvillensis Meek, 1873, Ann. Kept. U. S. Geol. Sur. Terr, for 1872, p. 502;

White, 1879, idem for 1877, p. 315. PL 9, Fig. 4a. 

Cassiope whitfieldi White, 1876, U. S. Geog. and Geol. Sur. West 100th Meridian, vol.

IV, p. 196, PI. 18, Fig. la.

Original description of Cassiope whitfieldi :

"Shell moderately large, elongate-conical, umbilicate; volutions apparently about twelve, prominent and prominently angular below the 

middle of the visible portion, slightly concave from the prominent revolving angle to the suture below, also very slightly and somewhat 

irregularly concave from that angle to the suture above. A little below the suture there is a rather small, shallow furrow, with its borders 

above and -below raised into more or less distinct revolving ridges. 

Upon the under side of the last volution, which is father strongly conVex, there are three small revolving ridges, one of them bounding the 

umbilicus; the other two are placed near each other above the middle 

of the space, and are continuous to the apex of the shell. It is between the two last-named ridges that the hinder edge of each succeeding volution joins the preceding one. Umbilicus moderately large and 

deep; aperture subovate in outline; outer lip sinuate, having a broad, 

shallow notch above its middle, projecting somewhat anteriorly, and 

rounded abruptly into the umbilicus.

^ Surface marked by more or less strong undulating lines of growth 

apparently without small revolving lines.

" Diameter of the last volution of our largest example, nearly 4£ 

centimeters; the full height of the same, when entire, must have been 

not far from 11 centimeters."

Turritella coalvillensis was originally described from fragments that 

are more or less eroded and do not show the umbilicus. When better 

preserved specimens were obtained from southern Utah they were
8TANTOK.] XENOPHORID^J. 133

described as a new species and referred to Cassiope, which according 

to the manuals of Zittell and Fischer is a synonym of Glaucoma.

In the more recent collections from Coalville there are several examples that unquestionably belong to Meek's species and yet they possess 

the umbilicus and other characteristic features of Cassiope whitfieldi.

The surface ornamentation varies considerably in different individuals. In some examples each whorl of the spire bears five well marked 

revolving ridges, two of which are adjoining the suture above and 

below, respectively, while the other three are close together in the middle of the whorl and the lowest of them is the largest, giving to the 

whorl its angular appearance. In other specimens, especially very 

large ones, one or both of the ridges immediately above the angle is 

obsolete.

Turritella martinezensis Gabb, from the Cretaceous of California, 

resembles this species quite closely both in form, and ornamention, but 

it is not umbilicate.

Locality and position. Near the base of the Cretaceous section at 

Coalville, Utah, and at various localities in southern Utah.

XENOPHORID^. 

Genus XESTOPHOBA Fischer von Waldheim.

SIMPSONI n. Sp.

PI. xxix, Figs. 4-6.

Shell small, trochiform, consisting of four or five volutions; spire 

moderately elevated with straight sides; periphery of last volution narrow, angular and somewhat produced; base nearly flat, with a rather 

small but distinct umbilicus. The aperture is very oblique, irregularly oval in outline, and with the inner lip slightly thickened. Surface 

of the spire marked by numerous faint, irregular pits and depressions 

that seem to have been caused by the adhesion of small pebbles and 

bits of shell in the manner that is characteristic of this genus. These 

irregularities of the surface are shown on internal casts almost as distinctly as on the shell itself. The surface also shows lines of growth 

that are especially prominent and strongly curved on the base of the 

shell.

Height of one of the largest specimens, 10mm ; greatest breadth, 

16mm.

There is no other described species in the American Cretaceous with 

which this need be compared, though comparisons with recent species 

show that it certainly belongs to Xenophora. There are 21 specimens 

in the collection, all more or less imperfect, but taken together they 

show all. the characters of the species.

The name is given in honor of Mr. Charles T. Simpson, of the U. S. 

National Museum.
134 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL. 106.

Locality and position. In the Pugnellus sandstone near Malachite 

post-office, and in Poison canyon, Huerfano park, Colorado; at the 

same or a somewhat lower horizon on the Arkansas river, 20 miles above 

Pueblo, Colorado.

NATICID^E.

Genus LUNATIA Gray.

.LUNATIA CONCINNA Hall & Meek '(sp.).

PI. xxix, Figs. 9 and 10.

Natica concinna Hall & Meek, 1856, Mem. Am. Acad. Arts and Sci., n. s. vol. v, p. 384,

PI. 3, Fijgs. 2a-d.

Natica moreauensis Meek & Hayden, 1856, Proc. Acad. Nat. Sci., Phila., p. 64. 

Lunatia concinna Meek, 1876, U. S. Geol. Sur. Terr., vol. ix, p, 314, PI. 32, Figs, lo-c;

WMtfield, 1880, Geol. Bl. Hills of Dak., p. 430, PL 12, Fig. 13.

Compare Natica olliquata Hall & Meek, 1856, op. cit., p. 384, PL 3, Figs. 1 a and &; and 

" N. rectilabrum Conrad, Jour. Acad. Nat. Sci., Phila., 2d ser., vol. iv, p. 344, PL 58,

Fig. 28.

Prof. Meek's revised description is as follows:

" Shell obliquely rhombic-subovate, or subglobose; spire moderate; 

volutions three 'and a half to four, convex, and separated by a deep 

suture, last one comparatively large; surface marked by fine, rather 

obscure, lines of growth, crossed by nearly obsolete, minutely flexuous, 

revolving striae, only seen on well-preserved specimens; aperture subovate, being straighter on the inner than the outer side; umbilicus, 

small and sometimes showing a slight tendency to develop a small 

revolving ridge within; inner lip adittle thickened and slightly reflected 

upon the body volution, above the umbilicus.

"Length of a mature rather gibbous specimen, 0.90-inch; breadth 

of same, 0.76 inch.

"This shell varies somewhat in formj some individuals being proportinally a little shorter, and having the body volution more ventricose than others. For a long time it was believed to be distinct, from 

N. concinna, and consequently the name JV. moreauensis was proposed 

for it. Since seeing a good series of specimens, however, showing the 

form and general appearance of the shell at various stages of growth, 

I am led to believe that it is not specifically distinct from the type of 

N. concinna, which is now believed to be a young individual. At any 

rate, small specimens before me of the same size seem to agree almost 

exactly with the type of 'N. concinna, while I am at a loss to separate 

these specifically from the larger individuals, such as those for which 

the name N. moreauensis was proposed."

The author then proceeds to compare this with the closely related 

species Natica obliquata and N. rectilabrum. According to Mr. Gabb 

all the names given above, and N. acutispira Shumard, are synonyms 

of Lunatia obliquata. This conclusion is quite probable, but I am unable 

to confirm it with the material at hand.
STANTON.] NATICID.2E. 135

The collections from Upper Kanab valley, "Utah, contain 9 specimens, two of which are figured, that are not distinguishable from rather 

small examples of this species. The inner lip is perhaps slightly 

straighter, the callous deposit smaller and the outer lip is somewhat less oblique, but in form and surface markings they agree almost 

exactly. The principal fact that causes me to hesitate to assign them 

to the described species is that they come from a lower horizon and 

nearly all of their associates are different. The types and all the specimens hitherto reported, with one exception, came from the upper portions of the Montana formation, and from its equivalents in the southernstates. In the Geology of the Black Hills of Dakota, Mr. Whitfield 

states that one cast not distinguishable from this species came from a 

much lower horizon, probably the Benton shales.

Locality and position. About 350 feet above the base of the Cretaceous section in Upper Kauab valley, Utah.

Genus GYKODES Conrad.

GYRODES DEPRESSA Meek.

PI. xxix, Figs. 11-14.

Gyrodes depressa Meek, 1877, U. S. Geol. Expl. 40th Parallel, vol. IV., Pt. 1, p. 159, 

PI. 15, Figs. 1 and 1 a.

Shell depressed subglobose, consisting of three or four rapidly increasing whorls, the last of which is very large; spire varying from depressed to moderately elevated and prominent; whorls in some examples 

distinctly truncate above, in others only slightly flattened or simply 

rounded to the distinct, impressed suture, subangular or very narrowly 

rounded below around the borders of the umbilicus, wJhich is broad and 

deep, but narrows rapidly within. Aperture ear-shaped, subangular 

above and broadly rounded below, oblique to the axis of the shell; outer 

lip forming an irregular curve; inner lip nearly straight and with the 

upper half reflexed and somewhat thickened. Surface marked by strong 

lines of growth.

Height of an average specimen, about 22min ; the greatest breadth, 

32mm. In some of the more elevated examples the height and breadth 

are nearly equal.

This description is drawn from.a large suite of well-preserved specimens obtained in Huerfano park, Colorado, that have been compared 

with the types and with other examples from the typical locality. The 

types are sandstone casts, more or less distorted by pressure, so that 

the spire is unnaturally low. In the original description the suture is 

said to be "channeled in such a manner as to be flattened within, owing 

to the presence of a revolving furrow just above it," but this feature is 

accidental, the flattened channel simply representing the thickness of 

the shell between the whorls. I have no doubt that the Colorado shells
136 COLORADO FORMATION vAND ITS INVERTEBRATE FAUNA. [BULL.IOO.

belong to Meek's species, especially since many of the associated forms 

are identical in the two regions.

The extreme forms represented by Figs. 11 and 14 seem sufficiently different to be regarded as distinct species, but there are many intermediate forms and every character by which they might be separated is 

variable, consequently I shall include them all under the one name for 

the present. The most nearly related species with which I am acquaiiated is Gyrodes petrosa Morton (sp.), from the Ripley formation of 

the Atlantic and Gulf border regions.

Locality and position. In the lower portidn of the Cretaceous section 

at Coalville, Utah, ranging upward to the top of the " second ridge;" 

abundant in the Pugnellus sandstone at many localities in Huerfano 

park, Colorado.

GTRODES CONRADI Meek.

PI. xxix, Figs. 7 and 8. 

Gyrodes conradi Meek, 1876, U. S. Geol. Sur. Terr., vol. IX, p. 310, Figs. 33-36 in text.

Original description:

" Shell obliquely depressed-subglobose, the height being about seveneighths the breadth; volutions four to five, increasing rapidly in size, 

the last one forming about nine-tenths of the entire bulk, rounded on 

the outer side, somewhat produced and acutely carinated around the 

middle below, and, like those of the spire, with the truncation of the 

upper edgemoderatelybroadandalittleconcave; spire much depressed; 

umbilicus very broad and somewhat funnel-shaped, with its marginal 

angle prominent, acute, and regularly and rather distinctly crenate, 

while some distance within there is a second less prominent, linear, 

revolving ridge; aperture sub-rhombic and about twice as high as wide, 

distinctly angular at the termination of the revolving carina of the 

under side of the body-volution below, and obtusely angular above; 

outer lip very oblique, being produced above, and thence nearly straight, 

and extending obliquely backward and downward to the basal angle, 

where it connects with the lower extremity of the thin inner lip by a 

small, sharp sinus, or emargination; surface nearly smooth, or having 

obscure lines of growth, that become stronger and show a tendency to 

gather into little wrinkles on the upper truncated part of the volutions, 

while on well-preserved specimens the faintest possible traces of fine 

revolving striae may be seen by the aid of a magnifier.

"Height, 0.91 inch; breadth, about 1.10 inches; height of aperture, 

0.86 inch; breadth of same, 0.43 inch."

Some larger specimens from Huerfano park, Colorado, are proportionally somewhat more elevated and have, a narrower umbilicus than 

the type, with which they agree in all other respects.

This species is very closely related to Gyrodes pansus Stoliczka, from 

the Cretaceous of southern India, and it may also be compared with G. 

crenata Conrad, from the Eipley formation.
STANTON.] NATICID2E. 137

Locality and position. The type was found on Cheyenne river, South 

Dakota, in strata supposed to belong to the Fort Benton shales. The 

additional examples above mentioned came from the Pugnellus sandstone on Williams creek and Poison canyon, Huerfano park, Colorado.

Genus AMAUBOPSIS Morch. 

AMAUROPSIS BULBIFORMIS Sowerby (sp.). 

PL xxx, Figs. 2-4.

Natica fatlbiformis Sowerby, 1832, Trans. Geol. Soc. Lond., 2d ser., vol. in, p. 418, PL

38, Fig. 13; d'Orb., Pal., Fran<?., Terr. Cr6t., Ga8te"ropodes, p. 162, PL 174, Fig. 3;

Goldfusa, Petrefacta Germ., p. 112, PL 199, Figs. 16 and 17; Zekeli, Die Gastropoden der Gosaugebilde, p. 45, PL 8, Fig. 2. 

Ampullina lulbifornm Stoliczka, Sitzungsber. k. Akad. d. Wissenschaften, Wien,

Bd. 52, p. 146; Pal. Indica, Qretaceous Fauna of Southern India, vol. II, p. 300, PL

21, Figs. 11-15. 

Compare Amauropsis alveata (Con.) Gabb, Pal. California, vol. I, p. 1J.O, PL 19, Fig. 59.

Shell large, elongate-ovate, not umbilicate, consisting of seven or 

eight rapidly increasing, moderately convex, shouldered whorls; spire 

elevated and prominent, the apical angle varying from about 50° to 

65°; sutures deeply channeled; aperture elongate-ovate, contracted 

behind where it is separated from the body of the shell by the channeling of the suture, somewhat produced and subangular in front; 

outer lip thin and sharp; inner lip nearly straight, moderately thick, 

anteriorly flattened, a>nd reflected so as to form a sharp projecting 

ridge. Surface marked by lines of growth and by numerous revolving 

lines of minute punctatioiLHhat are always visible on well preserved 

specimens, and on a few examples are situated in well-defined revolving 

furrows, giving the shell in these rare cases a distinctly striate appearance.

Length of an average specimen, 77mm ; breadth, 47mm . The length of 

the largest specimen in the collection is 92mm .

I have seen no good European examples of this species with which to 

make direct comparisons, but, judging from the published figures and 

the comments of the authors who have described it, itis quite variable in 

form, several of the published figures differing more from Sowerby's 

original drawing than our specimens do. In those in which the aperture is represented as complete it is more broadly and regularly 

-rounded than in the shells before me. This and other very slight dif-* 

ferences that might be pointed out do not seem to me sufficient basis 

for proposing a new name. The species is already known to have had 

a wide geographic range in Cretaceous time, as it occurs in the Turonian 

of France, in the Gosau beds of Austria, and in the Cretaceous of 

southern India, where it is said to range through the entire Cretaceous 

series developed there. I suspect that some of the California fossils 

referred by Gabb to Amauropsis alveata really belong to this species, 

although he states that they are umbilicated.
138 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA.

I follow Zittel in referring this species to Amauropsis.

Locality and position. Common in the Pugnellus sandstone at several localities in Huerfano park; rare in the upper part of the Benton 

shales on the Arkansas river above Pueblo, Colorado.

AMAUROPSIS? UTAHENSIS White (sp.). 

PI. xxx, Fig. 1.

Lunatia utahensis White, 1876, Geol. Uinta Mts., p. 122.

Euspira coalvillemis White, 1879, Ann. Rept. U. S. Geol. Sur. Terr, for 1877, p. 310, PI. 

4, Figs. 2a and ft.

Eevised description:

"Shell subglobose; spire small, conical, acute, but not much 

extended; volutions about eight when the apex is entire, last one 

inflated, and, when adult, extended a little in front, and also posteriorly, near the border of the aperture; aperture obliquely ovate-semilunar, somewhat abruptly rounded anteriorly; callus of the inner lip 

'apparently not much thickened, but thicker anteriorly than posteriorly; columnella riinate or almost solid, and nearly covered by the 

callus of the inner lip, which seems not to be so closely appressed 

against it as it is against the body-volution farther back. Surface 

marked by the ordinary lines of growth. The figures on plate 4 are 

restorations of this species, all the numerous examples in the collections being crushed except one or two sandstone casts. The examples 

being somewhat numerous, afford a view of all the features shown by 

the figures.

" Length, from, the apex to the anterior end of the aperture, about 

4cm ; breadth, across the aperture and body-volution, about 3£cm."

The material on which this species was based is very imperfect and 

unsatisfactory, though it seems to justify the restoration given in the 

figure. In the National Museum collection there is one specimen, from 

another locality, of the same general form, that has a broad, open, 

Oyrodes-tike umbilicus, but it seems hardly possible that it can belong 

to this species, or even to the same subgenus.

In the second publication of the species the specific name was inadvertently changed from utahensis to coalvillensis and the original name 

was restored by the same author.1

According to Zittel 2 Euspira can not be retained even as a subgeneric name, and forms without an umbilicus resembling this and the 

species described above are by him referred to Amauropsis^ though it 

seems to me that the species now under consideration might be referred with equal propriety to Ampullina or to Cernina.

Locality and position. Near the base of the Cretaceous section at 

Coalville, Utah.

1 Ann. Eept. U. S. Geol. Sur. Ter ^ for 1878, p. 29. * Handbuoh der Palseqntologie, n, p. 221.
STAOTOH.J NATICID^E, RISSOID^E. 139

Genus SIGARETUS Lamarck*

SlGARETTJS (EtJNATICINA?) TEXTELIS n. Sp.

PI. xxx, Figs. 5 and 6.

Shell thin, broadly ovate, consisting of three or three and a half rapidly increasing volutions, the last one forming the greater part of the 

entire bulk; suture linear, impressed; aperture la-rge, rhombic ovate, 

narrow and produced behind, broad and sinuous in front, the greatest 

breadth being in front of the middle; outer lip thin and sharp, irregularly convex in outline; inner lip somewhat thickened and reflected, 

almost covering the narrow umbilical chink; columella arched. The 

inner lip is also concave in the middle, so that it and the narrow 

umbilicus are concealed when the aperture is filled with rock.

Surface marked by distinct revolving filiform lines that are not quite 

a millimeter apart on the body whorl, and by crowded, wavy transverse lines that are just visible to the unaided eye. On several of the 

specimens the revolving sculpture is very faint on an area of 2 or 3mm 

wide bordering the outer lip, and the lines of growth are there more 

distinct.

Length of the largest type, 15mm ; breadth, 12mm.

The generic relations of this species are rather obscure, and the 

specimens in hand are not very well preserved. Mr. Charles T. Simpson, of the department of mollusks, U. S. National Museum, through 

whose courtesy I was enabled to make comparisons with recent species, 

decides that it is most nearly related to Sigaretus and to the subgenus 

Euncuticina of Fischer (=N~aticina Gray).

Naticina obliqua Gabb, from the Tejon formation of California, is the 

only other American species that has been referred to the Cretaceous, 

and it is plainly different from ours.

Locality and position. Upper Kanab valley, Utah, about 300 feet 

above the base of the Cretaceous section.

RISSOID./E.

Genus MESOSTOMA Deshayes. 

MESOSTOMA OCCIDENTALIS n. sp.

f

PL xxx, Figs. 7 and 8.

Shell scalariform, with about eight or nine convex whorls; sutures 

deeply impressed. Surface marked by numerous moderately strong 

transverse costae, that pass entirely across the whorl arid are about as 

broad as the interspaces, and by more closely arranged, fine, revolving 

lines. On each of the larger whorls there are about twenty of the 

transverse costae and about twelve or fifteen revolving lines.
140 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BOLT.. 108.

The aperture is obliquely ovate in outline, slightly narrowed behind 

and a little produced or sub-canaliculate in front. Outer lip thin and 

sharp; inner lip somewhat reflexed and thickened below; peritreine 

not continuous, columnella somewhat arcuate.

. Length of one of the types with the apex restored, about 13mm ; greatest diameter, about 5mm . Some fragments of the same species evidently 

belong to shells with about double these dimensions.

With the imperfect material with which the paleontologist must 

usually deal, it is very difficult to assign such forms as this to the genus 

to which it belongs. Its general form and the character of the ornamentation are duplicated in Cerithium, Scalaria, and Rissoa, or at least 

in species that have been referred to those genera. The fact that in 

our species the peritreme is not continuous prevents its reference to 

either Scalaria or Eissoa. It seems to be very nearly related to some 

of the Cretaceous species of Mesostoma figured by Holzapfel,1 and I 

have therefore placed it provisionally in that genus rather than in 

Ceriihium. No described species from the American Cretaceous known 

to me is nearly related to this one, though Cerithium lallierianum var. 

suciense Whiteaves, seems to belong to the same general type.

Locality and position. In the Pugnellus sandstone, at several localities in Huerfano park, and in the upper part of the Benton shales on 

the Arkansas river above Pueblo, Colorado.

PYRAMIDELLID^E.

Genus EULIMELLA Forbes.

EuLiMELLA?.FUNicuLA Meek.

PL XXX, Fig. 9.

Eulima funicula Meek, 1873, Ann. Rept. U. S. Geol. Stir. Terr, for 1872, p. 506. 

Eulimella? funicula White, 1876, U. S. Geog. and Geol. Sur., West 100th Meridian. Yol.

iv, p. 197, PI. 18, Fig. 6; 1879, Ann. Rept. U. S. Geol. Sur. Terr, for 1877, p. 316, PI.

9, Fig. 10a.

Original description:

"Shell subterete or elongaterconical; spire regularly tapering from 

the middle of the body volution to the apex, or with very slightly convex slopes; volutions about twelve, flattened; last turn not much 

enlarged, subangular around the middle; suture merely linear; aperture ovate or rhombic-subovate; inner lip slightly thickened and reflected. Surface smooth.

"Length, 0.65 inch; breadth, 0.20 inch; divergence of slopes of spire 

about 19°.

" " This shell has much the appearance of a slender Nisso, but it certainly wants the umbilicus seen in that genus, its axis not being in the 

slightest degree perforated. It is even like some recent species of JEuli-

>Die Mollusken der Aachener Kreide, Palseontographica, Bd. 34, p. 129 et aeq.
STANTON.] PYRAMIDELLID^. 141

mella, and may possibly have to take the name Eulimella funicula, 

when its generic characters can be more clearly determined from the 

examination of good specimens. The best examples I have seen do not 

show the extreme apex of the spire, or very clearly the form of the 

aperture. So far as can be determined, however, its columnella does 

not seem to present the straightness seen in JEulimella. I know of no 

closely allied Cretaceous species. 

" Locality and position. Cretaceous at Coalville, Utah." 

Some specimens from the north fork of Yirgin river were described 

by Dr. C. A. White, who afterward added the following note on the 

species:

"The examples described and illustrated by me (loc. cit.) were published before I had seen either Mr. Meek's types or his drawings, having 

access only to his published descriptions. Subsequently comparison 

raises a doubt as to their specific identity, but they are evidently congeneric. My examples were more robust than Mr. Meek's, with a 

wider apical angle. It is possible that neither of these forms should 

be referred to Eulimella, but they certainly agree more nearly with the 

characteristics of that genus than with any other, so far as they are 

yet known."

Genus CHEMNITZIA d'Orbigny.

CHEMNITZIA? COALVILLBNSIS Meek.

PI. xxx, Figs. 10 and 11.

Tnrbonilla (Chemnitziat) coalvillensis Meek, 1873, Ann. Kept. U. S. Geol. Sur. Terr, 

for 1872, p. 505; White, 1879, idem for 1877, p. 305, PI. 9, Figs. 5o and fc.

Original description:

" Shell elongate-conical; volutions ten or eleven, moderately convex; 

last one not much produced below, rounded, or sometimes obscurely subangular around the middle; suture well denned; aperture rhombicsuboval, being angular above and apparently a little so below; inner 

lip slightly thickened, rather deeply arched, a little reflected, and closely 

appressed below; outer lip thin. Surface ornamented by rather strong, 

simple, regular, nearly or quite straight vertical ridges, crossed by regularly disposed revolving lines (about ten or eleven of the ridges and 

five or six of the revolving lines being seen on each volution of the 

spire), while only the revolving lines are continued below the middle 

of the body volution.

"Length of a large specimen, 1 inch; breadth, 0.40 inch; angle of 

spire, from 20° to 25°.

" None of the specimens of this species yet seen are quite perfectly 

preserved at the base of the aperture. Some of them look as if there 

liad been a slight angularity there, while others, differing in no other 

respect, present appearances that leave room for doubt on this point. 

In some of its characters this shell reminds one of the fresh-water Go-
142 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL.IOO.

niobasis, to which I was at one time much inclined to refer it, and I am 

hardly quite sure yet that it may not have to take the name Goniobasis 

coalvillensis. Many authors refer very similar shells to Chemnitzia, 

but it has not so large and produced a body volution and aperture as 

the forms to which Mr. Conrad and Dr. Stoliczka propose to apply 

that name. If found in any of the Paleozoic rocks, most geologists 

would refer it to Loxonema of Phillips. Whether or not the nucleus or 

apex of its spire was covered as in the typical species of Turbonilla, I 

have been unable to determine. It is a far larger shell, however, than 

the species upon which that genus was founded.

"Specifically, this shell seems to be related to Turbonilla spillmani 

Conrad (Jour. Acad. Nat. Sci., vol. IY, new series, PI. 46, Fig. 28), but 

its vertical folds or costae are straighter, less crowded, and less numerous, while its revolving lines are smaller and more numerous. Its 

aperture also certainly differs in being decidedly more angular above, 

and probably somewhat so below. It may likewise be compared with 

Scalaria mathewsonii Gabb, from Cretaceous rocks of California, from 

which it differs in having less convex volutions, or less rounded aperture, less crowded vertical ridges, and more distinct and coarse revolving lines.

" Locality and position. Coalville, TJtah; from below the lowest heavy 

bed of coal at that locality. Cretaceous."

The figures of this species hitherto published do not give a correct 

idea of it, because the specimen drawn had lost nearly all of the shell 

and consequently the transverse costae are less prominent and more 

broadly rounded than they should be. The examples figured on PI. 

xxx are from the typical locality and certainly belong to Meek's species. They show the character of the ornamentation and the extremes 

of variation in form, but they do not give any additional information 

concerning the generic relationship of the shell.

Some fragmentary specimens that apparently belong to the same 

species were collected from shales in the " third ridge " of the Coalville 

section, about 1,500 feet above the bed in which the types were found.

CHEMNITZIA? sp.

Turbonilla (Chemnitzia) melanopm (Con.?) White, 1876, U. S. Geog. and Geol. Sur.

West 100th Merid., vol. iv, p. 197, PI. 18, Fig. 10a. 

Not Turlonilla (Chemnitzia) melanopsis Conrad, 1860, Jour. Acad. Nat. Sci., Phila.,

2nd ser. vol. iv, p. 287, PL 46, Fig. 35.

The fragments figured by Dr. White and doubtfully referred to Conrad's species came from southern Utah. Other similar specimens have 

since been obtained from the coal-bearing series near the base of the 

upper Cretaceous in the same region, where it is associated with Glauconia coalvillensis, Barbatia micronema, and Corbula nematophora. They 

are too imperfect for specific description, but they are certainly distinct 

from Turbonilla melanopsis. The form is apparently rath.er short and
STANTON.] APORRHAID-E. 143

robust, and it is marked by strong transverse costsB. It resembles the 

Goniobasis cleburni White of the Bear Eiver formation, excepting that 

it is not quite so slender.

APORRHAID^E.

Genus APOEEHAI8 Dillwyn.

APORRHAIS (GONIOCHEILA) CASTORENSIS Whitfield.

PL xxxi, Fig. 1.

Aporrhais (Croniochdla) castorensis Whitfield, 1877, Prelim. Kept. Paleont. Black Hills, 

p. 38; 1880, Geol. Black Hills of Dakota, p. 427, PI. 12, Fig. 1.

Original description:

" Shell small, with a moderately elevated spire, composed of about 

four flattened or very slightly ventricose volutions, which are crossed 

by fine, flexuous, vertical folds, strongly directed forward in their course 

across the whorl,and also marked by fine, thread-like, revolving lines; 

suture distinct; apical angle about 40°, but slightly variable on different individuals. Body volution proportionately large and very strongly 

angular, or even carinate,' along the middle, flattened or slightly concave 

on the upper surface, and rapidly contracted below to the short, pointed, 

rostral beak. A second rather indistinct carination marks the surface 

a little below the first, but seldom or never extends to the margin of 

the lip. Outer lip expanded, strongly carinate on the back, and projecting in the middle to form a short, obtuse, slightly recurved digitation, and posteriorly extending along the spire to the base of the second volution above.

"This species somewhat resembles A. Mangulata M. & H.,1 but 

differs in the subdued character of the lower carination and in the 

strongly uniangular form of the body volution. Among a number of 

specimens none show the posterior canal extending above the point 

described, nor any evidence of a second digitation to the lip. The surface markings are quite superficial, but few specimens showing them, 

appearing quite smooth from slight exfoliation.

" We are extremely adverse to describing new species of this group 

of shells, as from their extreme liability to variation with different 

degrees of development they are easily mistaken, and we have feared 

that this might prove, on the examination of a larger and better collection of specimens, to be only a form of A. Mangulata M. and H., above 

referred to, but the single strong carination and the fact that it comes 

from a lower geological horizon and distant locality have induced us to 

separate it under a new name.

' ' Formation and locality. In the ferruginous sandy limestone on the 

east fork of Beaver creek, Black hills. Associated with fossils of the 

Fort Benton group."

i Paleontology of the United States Geological Survey of the Territories, p. 322, PI. 19, Fig. 6.
144 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL. 100.

APORBHAIS (PERISSOPTERA?) PROLABIATA White (sp.) 

PI. xxxi, Fig. 2.

Anohuraprolabiata White, 1876, Geol. Uinta Mta., p. 121.

Anchura (Drepanochrilua') prolabiata White, 1879, Ann. Rept. U. S. Geol. Sur. Terr, for

1877, p. 313, PL 7, Fig. 2a. 

Compare Anchura ? fusiformis White, 1876, U. S. Geog. and Geol. Sur. West 100th

Meridian, vol. IV, p. 190, PI. 18, Fig. 4a.

The following is Dr. White's description, with a few changes and 

corrections made necessary by the better material now before me:

Shell rather above medium size, subfusiform, spire elongated and 

tapering to a point, with nearly straight sides; volutions nine or ten, 

convex, the last one proportionally a little more enlarged than the others, 

the distal margin of each narrowly appressed against the proximal side 

of the next preceding one at the suture; wing large, broad, its outer 

border, nearly straight or slightly convex, its anterior extremity abruptly 

rounded to the broadly concave front margin; posteriorly the wing is 

divided by a deep rounded sinus into two portions, the posterior of 

which is narrow and directed backward and a little outward in a slender 

pointed process, while the anterior portion is° larger and subquadrate, 

with the outer angles slightly produced. Anterior canal and beak 

short; no posterior canal, though the outer lip is slightly produced 

backward and attached to the penultimate volution; inner lip and adjacent parts of the shell glazed, but without a distinctly marked callus.

Transverse costae slightly curved, scarcely half as wide as the interspaces, usually well marked on the whole spire, and gradually increasing in prominence on each succeeding whorl until on the back of the 

body volution they become narrow elevated ridges that extend from 

the suture to about the middle of the whorl, but on a few specimens, 

such as the original type, the transverse ornamentation is less prominent 

throughout and almost obsolete on the body whorl, and it is always 

more or less indistinct for some distance around the inner lip. In 

addition to these regular costae the spire sometimes bears a number of 

heavy varices that are not quite parallel with them. The entire surface 

is covered with crowded revolving raised lines that are barely visible 

without the aid of a lens. There is no carina on the body volution, but 

the posterior process of the wing is subcarinate, especially toward the 

extremity.

Length of,the largest specimen, 47mm ; breadth, across the wing and 

body volution, 34mm ; diameter of the body volution, 18mro .

No closely related species has been described from the American 

Cretaceous, though Rostellaria rostrata Morton, a Bipley species, 

should probably be referred to the same section. In the Cretaceous of 

Europe there are many similar forms, such as Aporrhais parkinsoni, A. 

reussi, A. sclilotheimi, etc., ranging from the Gault to the lower Senonian, < 

inclusive.
STANTON.] APORRHAID^E. 145

Some of the shells described by Dr. C. A. White as Anclmra ? fusiformis Meek, are certainly young individuals of Anchura prolabiata, 

but the figured specimen may represent a distinct species. The form 

of the wing seems to be different from that of A. prolabiata at any stage 

of its growth, but as none of the surface features are preserved it is 

impossible to determine its true relations. Prof. Meek stated that it 

does not belong to his species.1 These specimens came from several 

localities in New Mexico and their associates at some of them at least 

belong to the Colorado formation. This species, together with the 

European species above mentioned, forms a natural group that differs 

considerably from typical species of Anchura in general aspect, and 

especially in the form of the wing. The subgenus (of Aporrhais) Perissoptera proposed by Mr. Tate 2 in 1865 was evidently intended to 

include this group. Unfortunately I have been unable to obtain the 

original paper, in which the subgenus was described, and consequently 

I do not know what species was taken as the type. According to Mr. 

Gardner3 it is equivalent to his section I of Aporrhais, and includes A. 

parkinsoni and related forms, and also the recent A. occidentalis. The 

latter species, which was the type of Gabb's subgenus Arrhoges, has 

many features in common with the Cretaceous forms, the principal 

difference being that it has a distinct thickened inner lip, but whether 

it is placed in the same section with the fossil forms or not I think that 

Tate's name should probably be applied to the latter, as he was writing 

on " the so-called Bostellariae of the Cretaceous." More recently these 

forms have been referred to Lispodesthes, which I regard as an entirely 

distinct genus.4

Locality and position. Sink spring and Upper Kanab valley, Utah, 

occurring about 350 feet above the base of the Cretaceous section at 

the latter locality.

Genus ANCHUKA Conrad. 

ANCHURA (DREPANOCHEILUS) RUIDA White.

. PI. xxxi, Figs. 3 and 4.

Anchura ruida White, 1876, Geol. Uinta Mts., p. 120.

Anchura (Drepanocheilus) ruida White, 1879, Ann. Kept. U. S. Geol. Sur. Terr, for 

1877, p. 312, PL 7, Figs. 4a and 6.

Eevised description:

"Shell rather small; spire moderatelv elongate; volutions about 

seven, convex; suture impressed; wing moderately large, contorted, 

bearing at its extero-posterior corner a strong falciform process, the direction of which is nearly parallel with the axis of the shell; the outer

1 U. S. Geol. Eipl. 40th Parallel, vol. iv, p. 101.

'Quoted by Gabb: Am. Jour. Conoh., vol. iv, 1868, p. 148.

8 Gardner, J. Starkie, on Cretaceous Aporrhaidte: Geological Magazine, Dec. u, vol. u, 1875, p. 394.

« See p. 146.

Bull. 106 10
146 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [DULL, 106.

border of this process is slightly convex and continuous with the outer 

border of the body of the wing; the extero-anterior border of the wingabruptly rounded, from which to the very short beak the border is 

sinuous, almost sigmoid; posterior border of the wing deeply concave, 

its proximal half being slightly reflexecl outward, as if for the passage 

of soft parts corresponding to those that in allied genera occupy a posterior canal, as the curved sinus adjacent to the columella doubtless 

gave passage to soft parts corresponding to those that in Anclmra 

proper occupied the anterior canal or channel of the beak; inner lip provided with a distinct and moderately broad callus, which, in some cases 

at least, extends beyond the distal end of the aperture across the next 

volution, as seen by dorsal aspect of the shell; columella very slightly 

produced in front, and its apex flexed a little toward the dextral side of 

the shell. Volutions of the spire marked by many longitudinally oblique folds, which extend to the suture on the proximal side of the 

volutions, but not much beyond the middle on the distal side, and do 

not appear at all on either the body-volution or wiog. The whole surface marked by fine revolving striae, which are more distinct upon the 

last volution than elsewhere; last volution and wing also marked by a 

moderately strong carina, which terminates at the point of the falciform process.

" Length, 16mm ; breadth across the body-volution, including the 

wing, 12mm .

" This species agrees well with the subgeneric diagnosis of Meek for 

Dr&panocheilus, and in many respects it resembles A. (D.) americana 

Evans and Shumard sp., but it differs from that shell in its large anterior sinus, the deep sinuosity of the anterior border of the wing, and 

the reflexion of a portion of the posterior margin of the wing."

Locality and position. Upper Kanab valley, Utah, from same horizon 

as the preceding, species.

STROMBID^E. 

Genus LISPODESTHES White.

This name was proposed 1 to include two species^Lispodesthes nuptialis 

and L. lingulifera, now. regarded as one.

It was characterized as follows:

" Shell fusiform; anterior canal straight or slightly curved, and more 

or less produced; posterior canal extending nearly or quite the whole 

length of the spire, from near the apex of which it may be a little 

deflected; aperture winged; wing rather large, bearing two processes; 

the posterior process spine-like or falciform; the anterior process either 

in the form of a lobe or tongue-shaped; inner lip and spire, covered 

with callus."

To this description it should be added that in the adult the wing is

. i U. S.'Geog. and Geol. Snr. West lOOtli Hericl., vol. iv, p. 191
8TANTON.] STROMBIIXE. 147

greatly thickened and bordered externally by a raised rirn; the anterior canal is bent inward (from the observer in the dorsal view); and in 

the known forms there is no transverse sculpture on the volutions of 

the spire. In fact, it agrees with Pugnellus in every particular excepting that it has a long posterior canal.

in Zittel's Handbuch der Paleontologie, Lispodesthes is adopted as 

a subgenus under Aporrhais, but he includes in it Aporrliais reussi 

and other related forms of the type of Aporrhais (Perissoptera 9) prolabiata, above described, which, as it seems to me, is; entirely distinct. 

Holzapfel,1 following Zittel, has used the name only for such forms as I 

now refer to Perissoptera. In outline there is some resemblance between species of Perissoptera and Lispodesthes nuptialis, but the differences in all other characters seem to me of much greater than specific 

importctnce.

I would place LispodestJies in the Stroinbidse next to Pugnellus. 

LISPODESTHES NUPTIALIS White. 

PL xxxi, Figs. 5 and 6.

Anchura nuptialis White, 1874, Expl. Sur. West 100th Meridian, Prelim. Rept. Invert.

Foss., p. 24. 

Lispodesthcs nuptialis White, 1876, U. S. Geog. & Geol. Sur. West 100th Meridian, vol.

iv, p. 192, PL 18, Figs. 3a and &. 

Lispodesthes lingulifera White, 1876, ibid., PL 18, Figs. 2a and &.

Revised description:

"Shell small; body subfusiform; wing moderately large; spire 

somewhat prominent, acute, but so thickly encrusted with callus that 

the volutions are only obscurely shown, except where the callus is removed by exfoliation; revolving angle absent or obsolete upon the 

volutions of the spire, even when bared by exfoliation of the callus, 

but it is somewhat distinct upon the body-volution, being continued 

out upon the falciform process of the wing. This posterior falciform, 

process diverges widely from the axis of the shell, but by recurving it 

extends nearly as far backward as the apex of the spire; anterior process of the wing somewhat thickened, its breadth throughout about 

equal to that of the falciform process at the base, its length and breadth 

about equal, its outer end obliquely rounded; space between the two 

processes very narrow; from the base of the anterior process the border of the wing extends forward with a concave curve to the base of, 

and ends at, the long, slender anterior canal; posterior border of the 

wing concave ^and continuous with that of the falciform process on the 

one hand and with the callus-border of the posterior canal on the 

other.

" Length, from the apex of the spire to the end of the anterior canal, 

20mm ; breadth, measuring across from the base of the processes of the

 itollusken der Aaoliener Kreide, p. 120, PI. xu, Figs. 11-13.
148 COLOKADO FOEMATION AND ITS INVERTEBRATE FAUNA. [BULL. 106.

wing to the opposite side, 9mm ; spire, falciform process, and anterior 

canal each about 7mm ."

In the type specimen the wing is very thick and bordered externally 

by a raised rim and the anterior canal is somewhat curved inward. In 

these features, as well as the thick callus enveloping the spire, it resembles Pugnellus.

The types of Lispodesthes lingulifera were obtained at another locality 

though apparently from about the same horizon as the one above described. They are smaller specimens with thinner shells and wings of 

slightly different shape, but these differences are only such as might 

be seen at various stages in the growth of a single individual and are 

therefore not regarded as of specific importance. The author of the 

species concurs in this opinion.

It has already been shown in the note on the genus JJispodesthes that 

this typical species is not closely related to such forms as Aporrhais 

parTcinsoni, A. schlotheimi, etc., that have been referred to this genus by 

Zittel and Holzapfel, The only species known to me that seems to be 

congeneric with this one is Anchuraf newberryi Meek*. The description and figure of this species, given by Whitfield in the Geology of the 

Black hills of Dakota, show that it belongs to the same section with 

L. nuptialis.

Locality and position. Fifty miles north of Camp Apache, 5 miles 

west of Mineral Springs, Arizona; east of Mount Taylor, 1 mile south 

of Pajuate, New Mexico. At the former locality it is associated with 

Camptonectes platessa and at the latter with Pinna petrina, both of which 

occur elsewhere in the Colorado formation.

Genus PUGNELLUS Conrad.

PUGNELLUS FUSIFORMIS Meek (sp.).

PI. xxxi, Figs. 7-11.

Anchura? fusiformis Meek, 1877, U. S. Geol. Expl. 40tli Parallel,vol. iv, Ft. 1, p. 160, PL

15, Figs 2 and 2a. 

Not Anchuraf fusiformis (Meek) White, U. S. Geog. & Geol. Sur. West 100th Meridian,

vol. iv, p. 190, PI. 18, Fig. 4a. 

Lispodesthes? obscuraia White, 1880, Ann. Rept. U. S. Geol. Sur. Terr, for 1878, p. 30, PI.

11, Figs. 7a and b.

Shell, exclusive of the outer lip, fusiform, consisting of six or seven 

volutions, of which the last forms about five-sixths of the total length; 

the whorls of the spire are sometimes subangular above the middle, and 

the body-whorl is ventricose in the same region; suture distinct in 

young shells, but almost entirely covered in the adult by a very heavy 

spiral callus,, which extends backward from the inner lip over the

1 Macomb's Exped. from Santa 3?e. to junction of Grand and Green rivefa, p. 129.
WANTON.] STROMBIDJE. 149

apex of the spire; aperture narrow, oblong; outer lip in the adult 

greatly thickened and expanded, bordered externally by a.heavy ridge. 

The posterior expansion of the outer lip is broad falciform, slightly narrowed at the base, somewhat twisted so that it is not quite in the same 

plane as the rest of the margin, directed backward and outward, and 

terminating in a blunt point. About midway between this falciform 

process and the anterior end of the canal there is a smaller snbquadrate projection, directed downward and forward, in front of which 

there is a deep, narrow sinus, followed by a third projecting lobe that 

is broadly rounded and separated from the anterior end of the canal 

by a well-defined notch. The tip of the canal is slightly bent inward. 

The shell is very thin on the dorsum, which is the only portion not 

covered in the adult by a heavy callus. Surface smooth, excepting on 

the upper portion of the body-whorl, where it is marked by more or 

less prominent curved transverse costae that are sometimes shortened 

into nodes. From the front end of the last costa a rather prominent 

subangular ridge, corresponding to the angulation of the earlier whorls, 

passes out on thie outer lip and forms the upper (posterior) border of 

the falciform process. In the earlier stages of its growth the shell has 

a much more simple form.

Length of a large specimen, 41mm ; breadth, including the expanded 

outer lip, 39mm ; diameter of body-whorl, exclusive of lip, 16mm.

This description is drawn from a large collection of well preserved 

specimens from Huerfano park, Colorado. At several localities the 

species is very abundant in a bed of sandstone, which I have, for that 

reason, called the Pugnellus sandstone, as a convenient local designation.

The original types of Meek's species are imperfect sandstone casts 

from the neighborhood of Coalville, Utah, while White's types, also 

imperfect and showing different features, came from the Arkansas 

river above Pueblo, Colorado. Better collections recently made at both 

these localities prove that they all belong to the species that is so 

abundant in Huerfano park, and that it has all the characteristic features of Pugnellus.

The most nearly related form is Pugnellus manubriatus Gabb, from 

the Chico series of California, but the resemblance is not so close as to 

require minute comparisons.

Locality and position. At the localities mentioned in Colorado the 

species is confined to the upper part of the Fort Benton, being most 

abundant in the thin bed of Pugnellus sandstone, just beneath the 

Niobrara limestone, and very rare in the upper part of the underlying 

shales. At Coalville, "Utah, it occurs in the sandstone of the " second 

ridge," where it is associated with many of the same species that are 

found with it in Colorado. It has also been found at the same horizon 

at Bear River city, Wyoming.
150 COLORADO FORMATION AND ITS INVERTEBRATE. FAUNA. [BULL. 106.

TRITONIID^E.

Genus TEITONIUM Link.

TEITONIUM KANABENSE n. sp. 

PI. xxxi, Fig. 12.

Shell small, slender, fusiform, with six or seven rounded whorls, of 

which the last is somewhat inflated and below abruptly contracted into 

the short canal. Surface ornamented by very prominent narrowly 

rounded transverse costae, of which there are a.bout ten on the last 

whorl, crossed by strong elevated revolving lines, alternating with taint 

lines on the later whorls. There are also a few strong varices on the 

spire, representing the outer lip at various stages of growth.

The canal is short and somewhat bent and the aperture is ovate in 

outline. The outer lip is strongly dentate within and the inner lip has 

a thin callus.

Length of the type specimen, which is incomplete at both extremities, 

2imm . greatest breadth, 10mm .

Locality and position. About 350 feet above the base of the Cretaceous section at Upper Kanab, Utah. Collected by Mr. 0. D. Walcott.

FUSIBLE.

FUSUS SHUMAEDI H. & M.

PI. xxxi, Fig. 13.

Fusus -sJiumardi Hall and Meek, 1856, Mem. Am. Acad. Arts, and Sci., vol. v, 2d ser., p. 

391, PI. 3, Fig. 6; WMtfield, 1880, Geol. Black Hills of Dakota, p. 424, PI. 12, Figs.

7 and 8. . '

Whitfield's description is as follows:

" Shell small, with a moderately elevated spire and rather short 

rostral beak; volutions about six, strongly ventricose, and marked by 

comparatively strong, slightly oblique, vertical eostse or folds, which 

are directed forward on the lower part of the upper volutions and again 

recurved below, as seen on the body whorl, and also by finer striae of 

growth between the folds. The folds are crossed by numerous elevated 

revolving lines, with wider interspaces; suture well marked and distinct; aperture obliquely ovate, obtusely pointed above, and continued 

below into the short, narrow, rostral canal; columellar lip slightly 

thickened, but without visible folds or plaits.

" The specimen used is imperfect at both extremities and much of the 

surface shell removed; enough remains, however, to furnish the specific 

characters. The species may possibly belong to Mr. Meek's genus
STAOTOK.] FUSID2E. 151

Trachytriton; but although the vertical folds are distinctly marked 

where the shell is entirely removed, there is no evidence of revolving 

lines on the spaces between them, as required in the diagnosis of that 

genus. '

" Formation and locality. In a ferruginous sandy limestone on the 

east fork of Beaver creek, Black hills, associated with fossils referred to 

the Fort Benton group."

This species seems to have been abandoned by Prof. Meek, as he does 

not include it in his final work on the " Invertebrate Cretaceous and 

Tertiary Fossils of the Upper Missouri Country," and he there speaka 

of it as a possible synonym of Tracliytriton mnculum. The original 

%pe was found in the Fort Pierre group at the Great Bend of the Missouri. It is somewhat doubtful whether the specimen above described 

belongs to the same species. (See remarks on Pleurotoma Utzi, p. 161.)

Fusus GABBI Meek. 

PL xxxi, Fig. 14,

Fusus (Neptunca) galti Meek, 1873, Ann. Ropt. U. S. Geol. Sur. Terr, for 1872, p. 504 j 

'White, 1879, idem for 1877, p. 317, PI. 9, Fig. 9a.

Original description:

"Shell rather small, fusiform; spire moderately prominent, conical; 

volutions seven or eight, convex; last one somewhat ventricose in the 

middle, and rather suddenly contracted below into the narrow, slightly 

twisted, more or less bent, and apparently moderately produced canal; 

suture well defined; aperture rhombic-subovate, and rather suddenly 

narrowed into the canal below. Surface ornamented with equal, distinct, regularly disposed varices or vertical folds, about eight of which 

may be counted on the penultimate volution, and less on the body-whorl, 

where some of them become obsolete; crossing these are also seen fine 

revolving lines, and a little below the "suture, apparently a shallow 

revolving furrow that gives it a slightly banded appearance.

"Length, including canal, about0.87 inch; breadth,0.40inch; slopes 

of spire straight, and diverging at an angle of about 50°.

"The specimens of this species contained in the collection are quite 

imperfect, being mainly casts retaining more or less of the shell. From 

such material it is, of course, impossible to determine with much confidence the generic affinities of shells. I have, therefore, provisionally 

referred it to the genus Fusus, putting in parenthesis the name Neptunea with a mark of doubt, to indicate that I suspect it may belong to 

that group, with the limits assigned it by some conchologists. It 

seems, however, quite as probable to belong to Tritonidea, as understood by some.

"Locality and position. Coalville, Utah; from the Cretaceous beds 

below the lower heavy bed of coal mined at that place."
152 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL. 106. 

FUSUS (NEPTUNEA?) VENENATUS H, Sp.

PI. xxxii, Figs. 1 and 2.

Shell fusiform, rather large; spire conical, equaling or exceeding 

the aperture and canal in length; volutions about six, convex, obliquely flattened above; last whorl abruptly contracted into the canal, 

which is not complete in any of the specimens, but was evidently rather 

short and bent to the left (in aperture view).

Surface with numerous thread-like revolving lines and a row of 

prominent rounded nodes, of which there are about twelve on each 

volution. In the shells with more elongate spires like the largest one 

figured, this row of nodes is near the middle of the whorls of the spire, 

while in those that are more depressed it is near the suture. The 

nodes are not conspicuous on the earlier whorls. Aperture, exclusive 

of canal, oval; inner lip with a moderately thick callus; outer lip unknown.

Length of largest specimen, exclusive of canal, 72"'m ; breadth, 43'nm .

The collections from Huerfano park contain a large number of fragmentary specimens that I have placed in this species. They vary considerably in form, the extreme being shown by the two specimens'figured. These two would hardly be regarded as belonging to the same 

species if it were not for the fact that other examples seem to be 

exactly intermediate between them.

In size and general appearance this species has some resemblance to 

Fusus (Serrifusus) dakotensis M. & H., but the volutions are not at all 

carinate, as in that species, and the form of the aperture is different.

Locality and position. In the Pugnellus sandstone on Williams 

creek; in Poison canyon, and other localities in Huerfano park, Colorado.

Genus TRITONIDEA Swainson.

TRITONIDEA? HUERF'ANENSIS n. sp.

PI. xxxi, Fig. 15.

Shell rather small, short fusiform, spire elevated, about equal in 

length to the aperture and canal; whorls six, ventricose, abruptly 

contracted just below'the suture so that they have a shouldered appearance, with prominent rounded nodes on the shoulder of the body-whorl. 

On the spire these nodes are elongated into transverse costae that completely cross the exposed portion of the whorl. Surface also marked 

by numerous flat revolving lines that are broader than the spaces 

between them. Aperture not seen.

Length of the type specimen, 23mm ; breadth, 14ram.

In general appearance this species is not very different from some of 

the smaller individuals of Fusus (Neptuneaf] venenatus with which it
STANTON.] FUSIDJE. 153

is associated. It differs, however, in the shouldered character of the 

whorls as well as in all the details of surface ornamentation.

Locality and position. Poison canyon, Huerfano county, Colorado, in 

the Pugnellus sandstone. =

Genus FASCIOLAEIA Lamarcc.

FASCIOLARIA 1? -WALCOTTI n. Sp.-

PI. xxxii, Fig. 5.

Shell small, slender fusiform, consisting of eight or nine convex 

whorls; spire elevated, about .equal in length to the last volution; 

last whorl merging into the rather short and slightly curved canal. 

Surface marked by numerous sinuous transverse costae and finer, 

closely arranged, revolving lines. On the penultimate whorl there are 

about thirty of the costse and about twenty revolving lines.

Length, 29nim ; breadth, 10mm .

The single type specimen is beautiful ly preserved, but as it is imbedded in a hard matrix from which it can not be removed without 

endangering it, I have not been able to see the character of the 

aperture nor to determine whether there are any folds on the columella. 

It seems, however, to be closely related to Fasciolaria (Mesorliytis) 

gracilenta Meek, from which it differs in its shorter canal, more numerous 

transverse costse, and more delicate sculpture.

Locality and position. Collected by Mr. C. D. Walcott about 350 

feet above the base of the Cretaceous section at Upper Kanab, southern 

Utah.

FASOIOLARIA? (CRYPTORHYTIS) UTAHENSIS Meek (sp.) 

PL xxxii, Figs. 3 and 4.

Fusns (Neptunea) utahemia Meek, 1873, Ann. Eept. U. S. Geol. Snr. Terr, for 1872, p.

505. 

Fusus? utaltensis White, 1880, idem for 1878, p. 34, PI. 12, Fig. 2a.

Original description:

"Shell of moderate size, short fusiform; spire rather depressed, conical; volutions about four; those of the spire a little convex; last one 

large and ventricose, rounded or very slightly flattened around the 

middle and contracted rather rapidly below into a narrow canal that is 

longer than the spire, and more or less bent to the left; aperture rhombic, angular above and narrowed and prolonged into the canal below. 

Surface, as determined from a cast in sandstone, with obscure vertical 

ridges, about twelve of which may be counted on the penultimate volution, while on the last, or body-whorl, they become nearly or quite 

obsolete. (Eevolving lines probably also marked the surface of the 

shell, though no traces of anything of the kind are seen on the cast, 

excepting a shallow furrow above the suture on the volutions of the 

spire.)
154 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL. 106.

"Length, including canal, about 1.90 inches; breadth, 0*91 inch; 

angle of spire, about 67°."

In the collections from Huerfano park, Colorado, there are a number 

of specimens that are believed to belong to this species although in the 

type and other examples from Ooalville, Utah, only the general form 

and a part of the surface features are preserved. The Colorado specimens show the following additional characters: The surface ornamentation consists of lines of growth and rather distant rounded transverse 

costae which never entirely cross the whorls of the spire and in many 

individuals are shortened into obtuse nodes, or become obsolete, especially on the last whorl. In some cases these nodes are almost con^ 

cealed by the succeeding whorl thus leaving the spire nearly smooth 

and giving an undulated outline to the sutures which are not very distinctly impressed and are sometimes glazed over by a deposit of callus. 

Some examples also show faint revolving lines. The outer lip is simple 

and sharp, and the inner lip has a thin deposit of callus which seems 

to have spread over the spire in the adult. The columella bears below 

the middle one very prominent fold that is hardly visible in the aperture view of a perfect specimen. The angle of the spire varies considerably as is shown by the figures, and the number of volutions is six 

or seven instead of four.

I am very much in doubt as to the generic relations of this species, 

and the material at hand is not sufficient to show all of its characters 

fully. It seems, however, to be allied to Fasciolaria f (Cryptorhytis) 

flexicostata M. & H. It is one of those early generalized forms that 

seem to stand between the Fasciolariidse and the Volutidse though this 

species is more closely related to the latter family.

Locality and position. In the "second ridge" at Coalville, Utah, and 

with similar associates in the Pugnellus sandstone, Poison canyon, 

Huerfano park, Colorado.

Genus PYEOPSIS Conrad.

PYROPSIS COLORADOENSIS n. sp.

PI. xxxii, Figs. 6-8.

Shell of rather large size, pyriform, -consisting of four or five rapidly 

increasing volutions; spire in some specimens much depressed, in others 

rather prominent; suture distinct, bordered below by a revolving 

ridge that gives it a channeled appearance; whorls bicarinate around 

the middle, the upper carina the stronger, obliquely flattened above 

and rather abruptly contracted below into the canal, which is moderately long and slightly curved. On the whorls of the spire only the 

upper slope above the greater carina is exposed. In addition to the 

carinae, that are prominent and more or less nodose on the body whorl,
BTANTON.] VOLUTIDJ2. 155

the surface ornamentation consists of numerous strong, granular revolving lines, usually alternating with finer ones and crossed by distinct 

lines of growth. Aperture elongate ovate, suddenly narrowed and 

slightly produced above to form a short posterior canal and more gradually contracted below into the rather broad anterior canal.

Outer lip thin and slightly dentate within ; inner lip comparatively 

thin, forming a broad thin glaze on the body whorl above, but thickening and narrowing below until it is free from the columella, leaving a 

distinct and deep umbilicus. There is a single oblique fold on the 

columella.

Length of one of the types, 77mitl ; greatest breadth, 49mm.

Compared with Pyropsis lairdi M. & H., which seems to be the most 

closely related described form, this species has a shorter and broader 

anterior canal, a larger umbilicus, only two carinse on the body whorl 

instead of three, and stronger revolving sculpture. Besides, our species has the short posterior canal and the dentate outer lip, both of 

which are entirely lacking in P. bairdi. In some respects it approaches 

Rapa cancellata Sowerby, from the Cretaceous of southern India.

Locality and position. In the Pugnellus sandstone on Williams creek 

and in Poison canyon, Huerfano park, Colorado. Some very imperfect casts from about the same horizon at Coalville, Utah, probably 

belong to this species.

VOLUTIDJE. 

Genus EOSTELLITES Conrad.

This genus was proposed in 1855 with Rostellites texana (= Volutilithes navarroensis Shumard) as the type._ In 1876 Gabb gave the 

name Volutoderma to the group to which this species belongs. In his 

recent discussion of the Yolutidae Dr. W. H. Ball1 has more fully characterized the genus and restored Conrad's earlier name. His description is as follows: "The genus Rostellites is characterized by a usually 

thick shell with a tendency to cancellated sculpture of distant narrow 

ridges, more or less nodose at the intersections; by an acute apex and 

trochoid, minute nucleus; by a tendency to a notch or sulcus in the 

outer lip near the suture; and by the presence of several well-differentiated plaits on the pillar. A few species are thin and the form is extremely variable. The surface is not glazed, the pillar is nearly 

straight, and the incremental lines are conspicuous."

Dr. Dall has kindly examined the three species described below and 

he regards all of them as members of this genus. Rostellites gracilis 

differs from the type of the genus in that the revolving sculpture is 

obsolete and the spire is glazed, at least in some examples, but these 

features are not considered of generic importance.

» Xr*as. Wagner Free Inst. of Sci., vol. 3,1890, pp. 71,72.
156 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL. 106. 

ROSTELLITES DALLI H. Sp.

PI. xxxin, Figs. 11-13.

Shell of medium size, slender fusiform; spire elevated but not quite 

equal to the aperture in length; volutions about seven, convex, with a 

narrow constriction below the suture; body whorl large and in some 

specimens rather ventricose. Surface ornamented by distinct revolving lines and prominent rounded, transverse costae, the latter dying out 

above the middle of the body whorl. On the last volution there are ten 

transverse costae and about twenty revolving lines. Aperture long and 

narrow, with a slight notch at the posterior end as indicated by the 

lines of growth; outer lip lirate within; inner lip with a thin deposit of 

callus. Pillar nearly straight, with three distinct oblique folds near the 

middle, the anterior fold being the stronger. The folds are scarcely 

visible in the aperture view of an unbroken specimen.

Length of a medium sized specimen, about 80 mm ; greatest breadth, 

25 mm . Other specimens are considerably broader in proportion to their 

length.

The apex is not preserved in any of the specimens so that the character of the nucleus has not been determined.

This species seems to be congeneric with Eostellites texanus Conrad, 

which is the type of the genus to which Gabb subsequently gave the 

name Volutoderma. Specificially it is closely related to Voluta (Rostellites) elongata d'Orb., which occurs in the Turonian of France, the 

Gosau beds of Austria, and the Arrialoor and Trichinopoly groups of 

southern India.

Internal casts are not easily distinguished from the following species 

with which it is associated, but the surface ornamentation is very different.

Localities and position. In the Pugnellus sandstone at many localities in Huerfano park, and at a slightly lower .horizon on the Arkansas 

river, 20 miles above Pueblo, Colorado.

EOSTELLITES AMBIGUA n. Sp.

PI. xxxm, Figs. 8-10.

Shell of rather large size, spindle shaped; spire elevated and rather 

slender, somewhat more than half the length of the aperture; whorls 

about seven in number, moderately convex, the last one very large; 

suture distinct, more or less channeled. Below the rounded border of 

the suture the whorl is slightly constricted or flattened. Surface ornamented by numerous closely arranged revolving lines and by larger 

curved transverse costae that are less conspicuous on the body whorl 

than on the spire, and that have a tendency to form nodes just below 

the suture.

The aperture is narrow, prolonged into the rather short canal, and 

with a short posterior notch. Outer lip thin, obscurely lirate within,
STANTON.) VOLUTIDjE. 157

and slightly reflexed; inner lip with a very thin callus. The pillar is 

slightly arched with tAvo distinct folds, the anterior of which is the 

stronger, and faint indications of two others behind them.

Length of an average specimen, 77mm ; greatest breadth, 24Ium. Other 

specimens show that the species attained a considerably greater size 

and sometimes had a more robust form.

One imperfect specimen of which a figure is given (PI. xxxm, Fig. 10) 

differs somewhat in the character of the ornamentation, the transverse 

costse being shortened into rounded nodes. Possibly it belongs to a 

different species; but the other specimens that certainly belong together 

show considerable variation in this character.

Forms similar to this have been referred to Fasciolaria by Stoliczka 

and others, but they seem to belong to the Volutidse. It is true, however, that in the Cretaceous the lines can not be sharply drawn between

the Volutidse and the Fasciolariidte; and we find different authors 

assigning such forms in some cases to Fasciolaria and in others to 

Volutilithes and other volutoid genera. Some forms of Piestochilus 

which was proposed as a subgenus under Fasciolaria by Meek are not 

very different in general aspect from this species.

Locality and position. Abundant in the Pugnellus sandstone on 

Williams creek and in Poison canyon; it also occurs at other .places 

in Huerfano park, and at about the same horizon at Eattlesnake butte, 

18 miles east of Walsenburg and on the Arkansas river, 20 miles above 

Pueblo, Colorado.

KOSTELLITES GEACILIS n. Sp.

PI. xxxiv, Figs. 1-3. .

Shell large, slender, fusiform, consisting of about seven volutions, 

the last of which comprises about three-fourths of the total length of 

the shell; whorls convex and rounded in the middle, constricted posteriorly, the body whorl gradually narrowed into the moderately long 

canal; suture linear, appressed, in some examples apparently glazed 

by a thin deposit of callus. Surface marked by rather distinct lines of 

growth and by curved transverse costee that cross only the convex portion of the whorl leaving the posterior constricted portion smooth. 

The costse are most prominent on the upper part of the spire, gradually 

becoming more distant and less conspicuous and disappearing entirely 

on the last whorl or sometimes earlier. One specimen also shows traces 

of numerous very fine revolving lines on the earlier whorls. 

" Aperture long and narrow, posteriorly acute and slightly einarginate; outer lip thin, sharp, and smooth within; inner lip with a thin 

deposit of callus that seems sometimes to spread over the spire in a 

thinner glaze. Pillar nearly straight with three very strong, subequal, 

oblique plaits near the middle.

Length of a medium-sized specimen, 110mm ; greatest breadth, 28mm . 

The largest of the figured specimens, which lacks the apex of the spire
158 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL. 106.

and the entire canal, measures, Avithout restoration, 109mm in length and 

49mm in breadth. This large specimen differs somewhat in form from 

the others and it is the one that shoAVS tine revolving striae on the earlier whorls of the spire. If better collections should prove that two 

species are represented the name here.proposed should be used for forms 

like that represented by Figs. 1 and 2 of PI. xxxiv.

I do not .know any described species nearly related to this one and 

its generic affinities are not very clear. In general form and in the 

character of the plaits of the columella it is quite like Rostellites. In 

other respects it suggests Volutomorpha, and perhaps it should be regarded as intermediate between these two groups.

Locality and position. In the Pugnellus sandstone near Malachite 

and in Poison canyon, Huerfano park, Colorado. About a dozen more 

or less fragmentary specimens were obtained.

CANCELLARIID^E.

Genus CANOE LLABIA Lamarck.

CANCELLARIA MALACHITBNSIS n. sp.

PI. xxxin, Figs. 6 and 7.

Shell small, short fusiform, comparatively thick; spire moderately 

elevated, conical, consisting of three or four whorls; body whorl very 

large, rounded, produced below into a short, broad canal. Surface 

beautifully cancellated by strong revolving and transverse lines. On 

the body volution there are about fifteen of the revolving lines of which 

two or three nearest the suture are considerably larger than the others 

and separated by broader furrows. On the spire only four revolving 

lines are visible.

The aperture is not complete in any of the specimens, but it is evidently narrow ovate iu outline, and the columella bears three strong 

plaits, of which the first and second are very close together, and the 

posterior one is more remote and the strongest.

Length of one of the larger specimens, 18mm ; breadth, 9mm.

Locality and position. In the Pugnellus sandstone near Malachite, 

Huerfano park, Colorado; represented by three specimens.

Genus ADMETOPSIS Meek. 

ADMETOPSIS EHOMBOIDES Meek. 

 PI. xxxin, Fig. 3.

Admetef rhomloides Meek, 1873, Ann. Rept. U. S. Geol. Sur. Terr, for 1872, p. 501.

Admetef gregaria Meek, 1873, ibid.

Admetopsis rhomloides White, 1879, idem for 1877, p. 317,' PI. ix, Figs. 6a and &.

Original description:

" Shell rather small, rhombic-suboval, or short subfusiform, the length 

being slightly more than twice the breadth at the widest part, which is
159 . CANCELLARIID^E. BTAHTON.] 

volutions subturreted.; depressed-conical, rather spire middle; the near 

entire the three-fourths about forming- one last convex; six, or five 

upper its near widest length, its of half than more and shell, the of bulk 

obliquely aii present to as so below narrowed abruptly and part, 

volutions; the of convexity the from deep rather "suture form; obovate 

notch small a to below narrowed and above subangular narrow, aperture 

two with provided is which columella, truncated the of base the at 

twisted the by formed is which of lower the folds, or plaits obscure small 

lY&le a placed is other the Avhile lip, inner truncated the of margin 

above, retreating slightly margin its with sharp, lip outer up; farther 

by ornamented Surface middle. the near or below, prominent more and 

volutions the on developed well usually are that folds, vertical distinct 

become but whorl, body the of .part upper the around and spire, the of 

lower the mark also lines revolving distinct moderately below; obsolete 

its on obsolete become to appear these but volution, body the of part 

found. usually are specimens as spire, the of those on and part, upper 

58°." about spire of angle inch; 0.21 breadth, inch; 0.37 "Length, 

rliom- Admete? names the gave Meek Prof. which to forms three The 

suggesting time same the at subfusiformis, A.9 Mid gregaria A.? boides, 

in abundant very are them, for designation generic a as Admctopsis. 

Coalville, at section Cretaceous the of base the near layers certain 

these of markings surface The obtained. were types the where Utah, 

more are examples the of most and preserved well seldom are fossils 

ornamenta- the that states Meek Prof. distorted. and crushed less or 

for reason chief his and species, the all in variable and similar is tion 

much are individuals some that been have to seems them separating 

(loc. them concerning remarks White Dr. others. than slender more 

think to inclined much am I examples many examining after " that cit.) 

to seems It most." at species two than more not represent they that 

present the for but species, variable one only is there that probable me 

refer shall I question, the decide fully shall collections better until and 

slen- the and rhomboides, Admetopsis to specimens ventricose short the 

synonym, a as gregaria A. treating subfusiformis, A. to ones elongate der 

done. already has White Dr. as former the of 

Meek. SUBFUSIFORMIS ADMETOPSIS 

2. and 1 Mgs. xxxiii, PL 

502. p. 1872, for Terr, Sur. Geol. S. U. Kept. Ann. 1873, Meek, sulfusiformis ? Admete 

7. Fig. ix, PI. 318, p. 1877, for idem 1879, White, snlfusiformis Admetopsis 

West Sur. Geol. and Geog. S. U. and 5a, Fig. in, PI. ibid., White, gregaria ?Admetopsi8 

I. 5a, Figs. xvui, PI. 198, p. IV, vol. Merid., 100th of 

description: Original 

breadth; the times three nearly length the with subfusiform, Shell " 

convex; eight, or seven volutions turretedj conical, elongated, spire 
[BULL.IOG. FAUNA. INVERTEBRATE ITS AND FORMATION COLORADO 160 

con- in denned well suture length; entire the half than more turn last 

equaling narrow, aperture whorls; the of convexity the of sequence 

nar- and behind angular shell, the of length entire the two-fifths about 

trun- the of base the at notch denned sharply small, a to below rowing 

lower its near folds small two bear to seems which coluinella, cated 

margin; lower truncated and twisted the by formed being one part, 

regular distinct, by ornamented surface thickened; little a lip inner 

body-volution the on obsolete quite or nearly are that folds vertical 

.on denned well quite lines revolving regular and part, upper its below 

on obsolete be to appear and part, lower its especially body-turn, the 

distinct. moderately growth of lines spire; the of those 

30°. about spire, of angle inch; 0.20 breadth, inch; 0.50 "Length, 

gregaria] [A. last the from strongly more even differs species This " 

more much a having rhomboides, species the from does form that than 

aperture. and body-volution smaller proportionally a arid spire elevated 

spe- The alike. much are forms three the however, ornamentation, In 

inner thickened more somewhat a shows consideration under here cies 

others." the of either in seen yet have I than lip 

Admetopsis to referred been have that Utah southern from fossils The 

more the if here, belong to seem above) references two last (see gregaria 

character. specific a as regarded be can form elongate slender 

at section Cretaceous the of base the Near position. and Locality 

Utah. southern in localities several at and Utah, Coalville, 

sp. n. HUMEROSA ADMETOPSIS 

5. and 4 Figs. xxxni, PL 

ones earlier the eight, about whorls fusiform; slender, small, Shell 

last the costse, transverse distinct numerous by marked and rounded 

orna- transverse The smooth. and shouldered distinctly three or two 

and spire, the of apex the near strongest proportionately is mentation 

channeled, or shouldered become whorls the as reduced gradually is 

pre- the on usually and whorl, body the on entirely disappears it until 

lines. revolving faint show.very specimens Some one. ceding 

the in as genus the of features characteristic the showing Aperture 

lip outer thickened; considerably lip Inner species. described other 

specimens. the of any in complete not 

. mm 8 breadth, ; mm 15 specimen, average an of Length 

character shouldered the by distinguished easily be may species This 

whorls. larger the of aspect smooth and 

it where Utah, southwestern city, Iron Near position. and Locality 

Corbula micronema, Barbatia coalvillensiSj Glaucoma with associated is 

40 About formation. Colorado the of species other and nematophora, 

collected. were specimens 
STANTON.J PLEUKOTOMID.E, ACT^EONID^E. . 161

PLEUROTOMID^E. 

Genus PLEUKOTOMA Lamarck. 

PLEUROTOMAH HiTzi Meek. 

PL xxxiv, Fig. 4.

Tnrria (Surcula) ? Utzi Meek, U. S. Geol. Sur. Terr., vol. ix, p. 386, Fig. 50 in text. 

Compare Fusus shumardi (H. &. M.) Wkitfield, 1880, Geol. Black Hills of Dakota, p. 

424, PI. 12, Figs. 7 and 8.

" Shell elongate-conical (or fusiform), thin; spire much produced and 

turreted; volutions about seven, distinctly convex, or subangular 

around the middle, and flattened or concave with an outward slope 

above the angle, and convex below; last one not larger than the regular enlargement of the others from the apex, each provided with about 

thirteen prominences or little obscure vertical folds, which on the angle 

of the last turn assume rather more the character of obscure nodes; 

entire surface marked by raised, revolving lines; aperture trigonoidoval, being biangular above and abruptly contracted below; beak, if 

any existed, unknown.

"Length (exclusive of the beak), about 2inches; breadth, 0.90 inch; 

slopes of spire somewhat convex, and diverging at an angle of about 

36°."

The only example of this species known to me is the imperfect type 

specimen, which does not show either the generic or the specific characters very well.

The small fossil described by Whitfield (loc. cit.) and referred by him 

to Fusus shumardi has fully as close resemblance to the earlier whorls 

of this species as it has to Fusus shumardi, and the fact that it comes 

from the Fort Benton group, the same horizon from which Turris hitzi 

was obtained, while Fusus shumardi came from a higher horizon, makes 

its identification with the former species more probable.

Locality and position. On the Missouri river opposite Fort Shea, 

where it is associated with fossils of the Colorado formation.

ACT^EONID^E.

Genus ACTION Montfort.

ACTION PROPINQTJUS n. sp.

PL xxxiv, Figs. 5-8.

Shell small, slender ovate, with six convex volutions; spire moderately elevated, acute; suture impressed or slightly channeled. Surface marked by fine, punctate,'revolving lines, of which there are about 

six visible on each whorl of the spire and about twenty on the body 

whorl. The aperture is narrow, acute behind and narrowly rounded 

in front. There is one prominent fold on the columella. 

Bull. 106 11
162 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL. 106.

Length of the larger specimen, 10 ram ; breadth, 5 mm .

This species is closely related to Actceon subellipticus M. & H., 

which occurs in the Port Pierre shales of Dakota. It has a larger 

number of whorls and fewer revolving strise, the form of the aperture 

is slightly different, and the body volution is more ventricose.

Locality and position. In the Pugnellus sandstone, Poison canyon, 

Huerfano jjark, Colorado, represented by three specimens.

BULLID^E.

Genus HAMINEA Leach. 

HAMINEA TRUNCATA n. sp. 

PL xxxiv, Figs. 9-11. .

Shell rather large; thin, subcylindrical; whorls two and a half or 

three, the last one very large and gradually expanding to the anterior 

end, where it is squarely truncate; spire depressed, not projecting 

above thelast whorl; sutures channeled. Surface smooth and polished, 

with faint wrinkles and lines of growth and very obscure traces of revolving stride. Possibly the thin outer layer of shell bearing the revolving strise has been exfoliated. The aperture is subtriang.ular, being _ 

narrow and acute behind and very broad in front. The outer lip is free 

from the preceding whorl for some distance, leaving a moderately deep 

narrow slit, below which it is almost straight to the front, where it is 

abruptly rounded into the straight anterior border.

Length of the largest specimen, 23ram ; greatest breadth, 18mra .

The depressed spire, the smooth surface, and the square-cut anterior 

end are the distinctive features of this species by which it may be separated from all the described Cretaceous forms known to me, though a 

number of recent species resemble it more closely in these respects.

Locality and position. In the Pugnellus sandstone, Poison canyon, 

Huerfano park, Colorado. Eepresented by three specimens.

AURICULID^E.

Genus MELAMPIJS Montfort.

MELAMPUS? ?

Melampus? -1 White, 1880, Ann. Rept. U. S. Geol. Sur. Terr, for 1878, p. 25, PI. 

19, Fig. 6a; 1883, 3d Ann. Rept. U. S. Geol. Sur., p. 444, PI. 5, Fig. 17.

This species, which has never been described or named on account 

of lack of sufficient material, was found in the lowest fossiliferous beds 

of the Cretaceous section at Coalville, Utah. Only one specimen has. 

yet been found.;
STANTON.] LIWSJ&ITtJE, NATTTTLID2E. 163

LIMN^EID^E.

Genus PHYSA Draparnaud.

PHYSA sp.!

Pkysa ? White, 1879, Ann..Eept. U. S. Geol. Sur. Terr.'for 1877, p. 307, PL7, 

Fig. 13ft; 1883, 3d Ann. Kept. U. S. Geol. Sur., p. 444, PI. 4, Fig. 5.

A single specimen of, Physa, too imperfect for specific description, 

was found by Dr. 0. A. White in the " second ridge " at Coalville, Utah, 

where it was associated with many marine species of the Colorado 

formation. It is the only example of the genus that has been found in 

that formation.

CEPHALOPODA. 

NAUTILOIDEA.

NAUTILIDvE.

Genus NAUTILUS Breynius.

NAUTILUS ELEGANS Sowerby.

PI. xxxv, Fig. 1.

Nautilus elegans Sowerby, 1816, Min. Conch., vol. n, p. 33, PI. 116; Sharpe, 1853, Monog.

Chalk Cephal. of England, p. 12, PI. 3, and many other European authors. 

Nautilus elegaris var. nebrascemia Meek and Hayden, 1862, Proc. Acad. Nat. Sci., Phila.,

p. 25.

Nautilus elegana Meek, 1876, U. S. Geol. Sur. Terr.,Vol. ix, p. 499, PI. 8, Figs. 2, a, 1>, o. 

Compare Nautilus texanus Shumard, 1860, Trans. St. Louis Acad. Sci., vol. i, p. 590.

Meek's description is as follows:

a Shell subglobose, broadly rounded over the periphery and on each 

side of the umbilicus, which is closed in young and medium-sized specimens, but becomes a little open in the adults; volutions increasing rapidly in size, considerably wider transversely than in the dorso-ventral 

direction, all of those within entirely embraced and hidden by the last 

one 5 aperture transversely reniform-sublunate, being profoundly sinuous on the inner side for the reception of the inner turns; margins of 

the septa arching forward a little near the umbilicus, slightly waved 

backward on the sides, then again curving very slightly forward as they 

approach the periphery, in crossing which they bend again almost imperceptibly backward; siphuncle placed a little outside of the middle 

of the septa; surface of the outer volution ornamented by regular flattened, transverse costse (about five times as broad as the narrow, shallow grooves between) and moderately distinct lines of growth, which, 

like the costse, in crossing the periphery, arch gracefully and deeply 

backward, parallel to the deep peripheral sinus of the margin of the 

lip.
161 COLOEADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL. 108.

" Length or greatest diameter, about 3.90 inches 5 height, 2.82 inches; 

breadth at aperture, 3.40 inches."

Locality and position. Ohippewa point on the upper Missouri river, 

in Fort Benton shales.

AMMONOIDEA.

LYTOCERATID^E.

Genus HELICOOEEAS d> Orbigny.

HELICOCERAS PARIENSE White.

PI. xxxv, Figs. 2-4.

ffelicoceras pariense While, 1876, TJ. S. Geog. and Geol. Sur. West 100th Meridian,

vol. iv, p. 203, PI. 19, Figs. 2a-d. 

Compare Ancyhceras annulatus Shumard, 1860, Trans. St. Louis Acad. Sci., vol. I,

p. 595.

Original description:

"Shell dextral; spire much depressed; whorls distinct, subcircular 

or very broadly oval in transverse section, increasing some what rapidly 

in size; surface marked by comparatively strong, rather abruptly 

rounded annulations, which cross the whorls, obliquely; annulations 

only slightly prominent upon the inner side of the whorls, but more 

prominent upon the upper and under sides; upon the outer side of the 

whorl each annulation bears a pair of prominent nodes, one on each 

side of the siphuncle, forming two dorsal rows of nodes along the whole 

length of the shell, the portion of the annulation between each pair of 

nodes being straightened and slightly flattened upon the back. The 

annulations are apparently always simple, never coalescing, and never 

failing to completely encircle the volution. The nodes are moderately 

prominent upon exfoliated specimens, and where the test is preserved 

they are seen to be subspinous or sharply nodose.

"Septa moderately distant, sometimes embracing two annulations,. 

but toward the aperture only one. Lobes all smaller than the saddles, 

the size in each transverse series gradually diminishing from the dorsal to the ventral one; the smallest saddle, the ventral, not being 

larger than the largest lobe, the dorsal; lobes all bifurcate, except the 

ventral, the inferior lateral lobe being but slightly so; the anterior portion of the space between the branches of the dorsal lobe occupied by 

two backward projecting points; the ventral lobe is simple, small, narrow, and serrate upon both sides. The saddles of the different longitudinal series all similar in shape, diminishing gradually in size from 

the dorsal far the ventral series; all broader than long, except the ventral one, the length and breadth of which are about equal; each partially parted at the middle; edges of all the lobes and saddles serrated 

or toothed.

The longest fragment in the collection measures about 7cm. At the
STAOTON.] LYTOCERATID/E. 165

larger end of this the long diameter is 15nun and the short diameter 

14'nm ; at the smaller end the long diameter is S^1 .

" This species is similar in aspect to H. Mortoni Hall and Meek, but 

differs from it in diminishing in caliber much more rapidly toward the 

apex, in the presence of a double series of nodes along the dorsum of 

the volutions, and in the proportions and details of its lobes and saddles.

"Position and locality. Cretaceous strata; southeast of Paria, Utah."

In the collection from Upper Kanab, Utah, there are many fragments 

of this species, some of which show the form of the spiral at least in 

the earlier stages. One of these showing one and a. half volutions is figured. The form is not constant, however, as one specimen is more 

closely coiled than this one, while others form a more open spiral and 

show a tendency to become straight at an early stage. The spire is 

only very slightly elevated, so that in side view the apex is almost concealed by the succeeding larger whorl.

The nodes on the periphery vary considerably in different examples. 

In some cases they are not developed on the earlier whorls, while other 

fragments of the same size bear two rows of sharp spines.

Excepting in its more depressed spire this species is very much like 

Jlelicoceras annulatum d'Orb., which is the type of the genus. Similar 

forms have frequently been referred to Crioceras, Samites, Ancyloceras, and other so-called genera that are based entirely on slight differences in form.

The species described by Shumard without figures under the name 

Ancyloceras annulatus seems to be closely related to this Utah form 

and may be identical with it.

CORRUGATUMn. Sp.

PL xxxv, Fig. 5.

Shell dextral, forming a very low, broad, open spiral; whorls with 

an ovate cross section, increasing rapidly in size, apparently not in contact. Surface marked by small, regular, rather closely arranged costae 

that pass obliquely entirely around the whorl. The costse are narrowly rounded, not quite as broad as the interspaces and without nodes 

or spines.

Full form of the shell and details of the septa not known.

The type specimen, which is about half of one volution, measures 

105ram in length, with sections 10 by 12mm at the smaller end and 18 by 

23ram at the larger end.

If the earlier whorls continue the low spiral indicated by the form of 

this fragment and by the oblique direction of its costse it must have 

been almost as much depressed as Heliooceras pariense, though in such 

evolute forms it is never safe to restore the entire shell from a single 

fragment.

Specifically this shell is easily distinguished from H. pariense by its
166 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [noLL.106.

more numerous and smaller costae without nodes, and by its larger 

size.

Locality and position. From the lower part of the Niobrara limestone on Turkey creek, Huerfano park, Colorado, where it is associated 

with Bucliiceras swallovi, Baculites gracilisl and Inoceramus fragilis.

Genus BACULITES Lamarck.

BACULITES GRACILIS ShumardU

PI. xxxvi, Figs. 1-3.

JBaculUes gracilis Shumard, I860, Trans. St. Louis Acad. Sci., vol. I, p. 596. 

Baculites ovatus (Say) White, 1876, U. S. Geog. and Geol. Sur. West 100th Meridian, 

vol. IV, p. 199, PI. 19, Figs. 4& and c.

Shell small, very slender; transverse section varying from broad ovate 

to subelliptical; surface sometimes nearly smooth, but usually with 

numerous distinct rounded costee or undulations that are strongest on 

the siphonal side from which they curve backward parallel with the 

lines of growth, gradually becoming fainter and disappearing before 

reaching the opposite side. In addition to the costae there are broad, 

rather obscure constrictions at intervals of about half an inch that completely encircle the shell. They are also more distinct on the siphonal 

side and are parallel with the lines of growth, passing nearly straight 

across the siphonal and antisiphonal sides and curved sharply backward 

on the flank:

Septum with six lobes and six saddles, all of the latter, excepting the 

antisiphonal one, symmetrically but not deeply divided; lobes much more 

slender than the saddles.

Length of the longest fragment in the collection, 106mm, diameters of 

the extremities, 10mm by 7£mm and 5mm by 4"ls1 , respectively.

This species differs from Baculites ovatus in its smaller size and more 

slender form, in the character of the surface ornamentation, and the 

details of the septa. The latter have the same general character in the 

two species, but on comparing specimens of the same size it is seen that 

in B. gracilis the septa are more distant and not so deeply incised and 

the lobes are narrower in proportion to breadth of the saddles.

The fossils above described include the specimens from southeast of 

Paria, Utah, that were doubtfully referred to B. ovatus by Dr. White 

(loc. cit.), a larger collection from Upper Kanab, Utah, where it is associated with many species of the Colorado formation about 350 feet 

above the base of the Cretaceous section, and several examples from the 

Niobrara limestone on Turkey creek, Huerfano park, Colorado.

Shumard's types were found on Shawnee creek, Grayson county, 

Texas, in strata that are believed to be approximately the equivalent 

of the Colorado formation. The species was not figured and I have 

never seen any Texas examples of it. Consequently the identification
STANTQN.] ' LYTOCERATBXE. ' 167

^ of the western specimens is somewhat doubtful, though they agree 

fairly well with the original description. Shumard states that the septum of his species has only four lobes, but it is evident from the detailed description that he counted the lateral lobes on only one side,

""" so that there are really six.

In form and surface ornamentation this species resembles Baculites 

baculoides d'Orb., but the periodic constrictions on that species are narrower and more distinct and the septa are much more complex.

BACULITES ASPER Morton? 

, PI. xxxvi, Figs. 4 and 5.

Baculitcs asper Mortou, 1834, Synopsis Org. Rem. Cret. Gr., p. 43, PI. 1, Figs. 12 and 

13, PI. 13, Fig. 2.

Iii the collection from Cinnabar mountain, Montana, there is a number of fragments of a small Baculites that are provision ally referred to 

N this species. They were first mentioned by Prof. F. B. Meek.1 They 

are associated with fossils of the Colorado formation. Recently Mr. 

W. H. Weed has collected specimens of the same form on Mission 

. creek, northern Montana, associated with Plioladomya papyracea and 

J Inoceramus undabundus, both of.which are Colorado fossils.

The form is slender, very gradually tapering, rather narrow ovate in 

cross section, and bearing on each side a row of distant more or less 

prominent tubercles. The tubercles are usually rounded, but sometimes they are slightly elongated, taking a crescentic form.

The diameters of the largest specimen are 14mm and llmin . Nearly 

all of the fragments are more compressed than this one.

The septa are not deeply divided, and are characterized by the great 

breadth of the saddles as compared with the lobes, but they are not 

well enough preserved to show all the details.

Mr. Gabb considered this species identical with B. aneeps Lamarck,2 

but most other authors have regarded them as distinct. The type of B. 

asper came from Cahawba, Alabama, but its exact strati graphic range 

in that region is not yet known. A form that is certainly identical 

with the one from Montana occurs in the Austin limestone of Texas 

and was referred to Morton's species by Dr. Eoemer.3 The material 

now at my disposal does not permit me to determine whether the same 

form occurs at a higher horizon or not. The one in the Montana and 

^ Bipley formations that is usually referred to B. aneeps seems to me certainly distinct from this one, and the fragments that Prof. Meek doubtfully referred to B. asper4 are probably also different.

»Ann. Eept. TL S. Gcol. Sur. Terr, for 1872, p. 475. 

' 2 Proc.. Acad. Nat. Sci. Pliila., 1801, p. 395. 

 Kreideb. v. Texas, p. 36. 

« TJ. S. Geol, Sur. Terr., Vol. IX, p. 404, PL 39, Tig. 10.
168 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BOLL. 106.

Baculites incurvatus Dujardin as figured by Schluter1 is a closely related form, that occurs in the "Emscher Mergel" of Germany. Several of its associates are considered identical with forms that are found 

in the Austin limestone and in the upper part of the Colorado formation.

AMALTHEID^E.

Genus BUCHICERAS Hyatt.

. BUCHICERAS SWALLOVI Shlimard (Sp.).

PI. xxxvn, Fig. 1; PI. xxxvin, Figs. 1-3.

Ammonites swallovi Shuniard, I860, Trans. St. Louis Acad. Sci., vol. i, p. 591. 

Buclmeras sivallovi White, 1876, U. S. Geog. and Geol. Sur. West 100th Meridian, vol. 

iv, p. 202, PI. xx, Figs, la, &, c.

Compare Plaoentlccras (perizianum ? var.) liar.dense Whiteaves, 1889, Gout, to Can. 

Paleont., vol. i, pt. 2, p. 158, PI. xx, Figs. 1 and 2.

Dr. White's description of the Utah fossils referred to this species is 

as follows:

"Shell moderately large, fiattened-discoid; sides greatly convex; 

dorsum [abdomen] narrowly flattened, the flattened space bordered on 

each side by a row of more or less distinct nodes; volutions three or 

four, partially embracing; umbilicus broad, its outline not clearly 

defined; deep for so discoid a shell, although it has a shallow aspect 

because of its breadth and want of definite outline, and exhibiting a 

large part of each of the inner volutions; aperture subovate in outline, 

its longest diameter directed from the center of the shell, narrowest at 

the outer end, where it is truncated by the flattening of the dorsum 

[abdomen]; sides of the volutions marked by prominent, somewhat 

flexuous, rounded costse, extending from the inner to the outer edge; 

the space between each two of these principal costse is occupied by one 

or two short ones which do not reach the umbilicus, but they end at the 

dorsuin [abdomen] like the others; upon each costa, near its dorsal 

[abdominal] end, there is an obtuse node, which, together with the dorsal [abdominal] nodes before mentioned, constitute a double row of nodes 

at each side of the dorsum [abdomen]. Saddles all broader, and simpler in outline than the lobes, none of the former being really digitate, 

and those near the ventral side of the volutions are nearly as simple in 

outline as they are in Geratites. l

" This shell presents some differences from the description by Dr. 

Shumard of A. swallovi, the principal of which is the absence of the 

nodes at the umbilical side of the volutions and of the distinct transverse ribs of the dorsum [abdomen] mentioned by him; but these are 

not regarded as essential specific characters.

I PaJseontograpMca, Vol. XXIV, PL 39, Figs. 6 and 7.
BTANTON.] A-MALTHEID^l. 169

®

"Full diameter of the shell, about 18cm ; transverse diameter of the 

aperture, nearly 5£cm ; long diameter of the same, about 8£cm .

" Prof. Hyatt writes me, after an examination of the specimen figured on PI. xx, that he regards it as a species of his genus BucUceras, 

but that, 'it differs fromJ?. syriacum, the type of the genus, in having 

larger lobes and cells more Ammonite-like.'

"Position and locality. Strata of the Cretaceous period; Glendale, 

Long valley, Utah."

The types of the species came from " 4£ miles north of Sherman, and 

bluffs of Eed river in Fanniri and Lamar counties, Texas." I have 

found a few fragments of it in the Niobrara limestone on Turkey creek, 

Huerfano park, Colorado. Mr. Walcott collected a number of specimens at Upper Kanab, Utah, about 350 feet above the base of the Cretaceous section. These show a considerable variation and some of

them have nodes around the umbilicus and the costce cross the abdomen, as in Shumard's type. Direct comparison of the Utah fossils 

with specimens from Texas shows that they are unquestionably identical. Other specimens that are smoother and have a narrower umbilicus, look exactly like the figure ot Placenticeras (perizianum ? var.) 

liardense Whiteaves, which occurs in the " Earlier Cretaceous " .of British Columbia.

Genus PLACENTICERAS Meek.

PLACENTICERAS PLACENTA Dekay (sp.)l 

PI. xxxix, Figs. 1-3.

Ammonites placenta Dekay, 1828, Ann. N. Y. Lyceum Nat. Hist., vol. n, p. 278, PI. 5,

Fig. 2, and of various authors. 

Ammonites (Placenticeras') placenta Meek, 1870, Proc. Am. PLilos. Soc., vol. xi, p.

429, and Ann. Eept. U. S. Geol. Sur. Terr, for 1870, p. 297. 

Placenticeras placenta Meek, 1876, U. S. Geol. Sur. Terr., vol. ix, p. 465.

Meek's description is as follows:

"Shell lenticular in form, attaining a large size: umbilicus small; 

volutions deeply embracing, compressed laterally, with sides converging from near the umbilicus to the periphery, which is very narrowly 

truncated and flattened or a little concave, with its smooth margins 

becoming more obtuse with age; aperture narrowly sagittate; surface 

generally smooth or only showing very obscure traces of curved, transversely-elongated prominences on each side, with sometimes a row of 

very small indistinct nodes around the umbilicus; in young, exfoliated 

shells also usually showing small, faintly defined, divaricating corrugations, directed backward around the outer half of each side.

" Large examples attain 2 feet or more in their greatest diameter. 

Young specimens, 3.70 inches in breadth, show a thickness of about 

0.90 inch, while large individuals are proportionally thicker, and on 

the periphery become more obtuse.
170 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BOLL. 106.

e

"Septa with 12 lateral lobes and as many sinuses on each side, in 

large examples crowded and very complex." [The detailed description of the septa is omitted, as it is more clearly expressed by the 

figure.] .

The species has hitherto been regarded as characteristic of the Montana formation and its equivalents, and I have been in doubt whether 

the specimens from the earlier beds should be referred to the same species, but the scanty material at hand does not show enough difference 

to permit of separation. Whether they are placed in a different species or not, I have no doubt that they were the direct ancestors of the 

form that is so abundant and well developed in the overlying formation.

The collection under examination consists of single fragments from 

Huerfano park and Eattlesnake butte, Colorado, and Coalville, Utah, 

and several more or less fragmentary .specimens from Upper Kanab 

valley, Utah. None, of these indicate a size of more than 8 or 10 inches 

in diameter. The only differences that have been observed between 

these and typical examples of the species is that the septa are somewhat less complicated and less crowded, and the periphery seems to 

have become rounded in somewhat smaller specimens, but the species is 

known to vary in these respects. A specimen from. Ellis county, Texas, 

where it is associated with BucMceras swallom, probably in the Eagle 

Ford shales, is still more closely like the typical form.

In the collection from Upper Kanab some examples are smooth, while 

others, such as the small specimens figured, show a tendency to become 

nodose, like the variety intercalare. The septum figured was visible 

only to the edge of the umbilicus, so that several of the small inner 

lobes and sinuses are not shown.

Genus PEIONOCYCLUS Meek.

This generic name was first suggested by Prof. M'eek J in 1871, but 

he then gave no diagnosis, and he did not again use the name in his 

writings until 1876, when he published 2 a description of the genus and 

of the two subgenera, Prionocyclus (typical) and Prionotropis, with P.. 

wyomingensis as the type of the former, and P. woolgari of the latter. 

In the same work the genus Mortoniceras was proposed with Ammonites vespertinus (=A. texamis) as the type. Meanwhile Neumayr had 

proposed 3 the name Scliloenliachia for the "very natural group of the 

Oristati," in which he evidently included forms that are referable to 

Prionocyclus and Mortoniceras, if not to Prionotropis, and in Zittel's 

Handbuch der Paleontologie these three names are treated as synonyms 

of SchloenbacJiia. They certainly have some features in common, the 

septa, especially, being similar in all our American species.

1 Ann. Eept. TT. S. Geol. Snr. Terr, for 1870, p. 298.

a T7. S. Geol. Sur. Terr., vol. ix, pp. 452,453.

 Dcutscli. geol. Gesellsch., Zeitscbr., Bd. xxvn, 1875, p. 887.
STAOTON.] AMALTHEID^E. 171

Some representatives of Prionocyclus and Prionotropis, including 

the types, were submitted to Prof. Alpheus Hyatt, and after examining them he states that they are generically distinct and that he also 

regards both as separate from Schloenbacliia properly restricted. I 

shall therefore use Prof. Meek's names.

As to the genus Mortoniceras, the specimens from the Colorado formation are hardly sufficient for generic determination and the original 

description will be simply copied under the old names.

PRIONOCYCLUS WYOMING-ENSIS Meek. 

PI. XL, Figs. 1-4.

Ammonites senatocarinatm Meek, 1871, Proc. Am. Philos. Soc., vol. xi, p. 429. 

Ammonites (Pleiiroceras ?) serratocarinatus Meek, 1871, Ann. Kept. U. S. Geol. Sur.

Terr, for 1870, p. 298. 

' Prionocyclus wyomingensis Meek, 1876, U. S. Geol. Sur. Terr., vol. IX, p. 452; White,

1880, Ann. Kept. U. S. Geol. Sur. Terr, for 1878, p. 35, PI. 15, Figs, la-e; Whitfield,

1880, Geol. Black Hills of Dak., p. 440, PI. 14, Figs. 1-3. 

Not Ammonites serratocarinatus Stoliczka, 1865, Cret. Cephalopoda of Southern

India, p. 57, PI. 32, Fig. 3. .

.Original description/^' M^t-li , ,.' / ,-'

"Shell attaining av rather large size; discoid, with periphery provided with a very narrow, prominent, serrated mesial keel, including 

the siphuncle. Yolutions increasing rather gradually in size, somewhat compressed laterally, and a little excavated without being distinctly channeled on each side of the ventral keel; inner ones but 

slightly embraced by each succeeding turn, and consequently well 

exposed in .the wide umbilicus. Surface ornamented with numerous 

unequal costse, some of the larger of which bear a small, somewhat 

elongated node near the umbilicus, and two closely approximated small 

nodes around the ventro-lateral margins, -where they all curve very 

strongly forward as they pass upon the periphery; spaces between each 

two of the large nodose costae occupied by from one to about three 

smaller ones. Septa unknown."

The costse are very irregular and vary considerably in strength on 

different individuals, but they retain the same character through all 

the stages of growth, excepting that the smaller intermediate ones almost disappear from the last whorl of very large specimens. Frequently 

two costse spring from a single node near the umbilicus and sometimes 

are again united in the node near the periphery, but in other cases 

they continue separate until they disappear near the keel. Very few 

specimens show more than one row of nodes near the periphery, and 

these are never developed into spines. The serrations of the keel are 

small and somewhat more numerous than the costte.

The septum, as shown in the figure, has the-same general character 

as that of Prionotropis icoolgari, the principal difference being in the 

greater breadth of the first lateral lobe.
172 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. IBULL. 106.

The breadth of the whorls is about two-thirds of the height in young 

specimens; in larger ones it is proportionally somewhat greater.

The species sometimes reached a size not less than 25cm in diameter. 

The outer whorl of a specimen that is 125mra in diameter measures 38mm 

in width by 48 in height.

Ammonites germari Reuss, which occurs in the Turonian of Germany, 

seems to be a closely-related species.

Locality and position. The types came from the valley of the Medicine Bow river, Wyoming; Whitfield's specimens were found "in siliceo-calcareous layers of Division No. 2, Cretaceous, on the east fork of 

Beaver creek, near Camp Jeuney, Black hills." It is common but usually not well preserved in a layer of calcareous sandstone immediately 

beneath the Niobrara limestone in Huerfano park and other places in 

southern Colorado arid along the eastern base of the Front range, and 

it occurs in eastern Utah.

PRIONOCYCLUS MACOMBI Meek. = 

PI. XLI, Figs. 1-5.

Prionocyclus? macomli Meet, 1876, Macoinb's Exploring Exped. from Santa Fe", N. 

M., to the Junction of Grand & Green Rivers, Geol. Rept., p. 132, PI. 2, Figs.

Original description:

"Shell discoidal; umbilicus shallow; somewhat less than the diameter of the last whorl from the ventral to the peripheral side, and showing all the inner turns; volutions increasing gradually in size, very 

slightly embracing, compressed so as to be nearly flat on the sides, but 

rounding into the umbilicus; periphery rather narrow, nearly flat, and 

provided with a small mesial carina, which is very slightly waved in 

outline; lateral margins of the periphery each having a row of small 

compressed nodes, arranged one at the termination of each of the costae, 

with their long diameters nearly parallel to the peripheral keel; sides . 

of each turn ornamented by from thirty-six to forty rather obscure, 

slightly flexuous costse, only every second, third, or fourth one of which 

extends across to the umbilical margin, where they are usually a little ' 

swollen.

" The septa are generally a little crowded in adult shells, and divided 

into two very unequal principal lobes on each side. Siphonal lobe 

slightly longer than wide, and ornamented by three branches on each 

side, the two terminal of which are a little larger and much less spreading than the lateral pair, and each ornamented by some five or six 

sharp digitations along the margins and at the extremity, while the 

first pair of principal lateral branches above the terminal ones are of 

nearly the same form as the latter, but more spreading, and the third 

pair are smaller and merely provided with a few digitations; first lateral sinus (dorsal saddle of old nomenclature) as long as the siphonal
STANTON.] AMALTHEID^E. 173

lobe, but much wider, and deeply divided into two unequal parts, of 

which the one on the siphoual .side is larger than the other, each of 

these principal divisions being ornamented by some four or five short, 

irreguiar branchlets, with obtusely digitate margins; first lateral lobe 

longer and slightly wider than the siphonal, and provided with some 

seven or eight short, rather unequal, merely digitate, and palmately 

spreading terminal and lateral branchlets; second lateral sinus narrower, but as long as the first on the outer or siphonal side, and much 

shorter on the umbilical, having two short, unequal, digitate, terminal 

branches at the end, and some three or four short, irregular divisions 

along the oblique margin of the umbilical side; second lateral lobe 

small, or scarcely more than twice as large as the auxiliary lobe of the 

siphoual sinus, and somewhat irregularly bifid, the divisions being 

short, and, like the lateral margins, more or less digitate.

" Greatest diameter of a specimen retaining only a small portion of 

the non-septate outer whorl, 4.40 inches; greatest convexity of same, 

0.95 inch; breadth of umbilicus, 1.35 inches; breadth of the last whorl 

from the, siphonal to the umbilical side, 1.80 inches."

The description of the septum above given was made out from a weathered specimen that did not show all the details clearly. The one I have 

figured is drawn from a smaller specimen, and it is therefore not quite 

so deeply divided as the one originally figured. There are also slight 

differences in the forms of the second lateral lobe and the second saddle, but these are in part due to errors in restoring the septum of the 

type. It will be seen by the figure now given that the. septum is very 

similar to those of the other species of Prionocyclus above described.

In the young stages of this species the costae are simple, linear, closely 

arranged, and strongly curved forward. The keel is then minutely 

crenate, with one crenation for each costa. After the third volution 

some of the costae are more strongly developed and bear nodes or small 

spines at their outer ends while the intermediate ones become obsolete. 

The crenations of the keel still continue numerous and small.

One of the specimens figured (Fig. 2) has unusually strong spines 

around the periphery and the larger costae are farther apart than in 

the other specimens of the same size.

This species is more closely related to Prionocyclus wyomingensis than 

to any other described American species. It can be easily distinguished by its more compressed form, by the greater regularity of the 

costse, and by the much greater difference between its young and adult 

stages.

Locality and position. The types came from "Banks of Canadian; 

lower part of Mid'dla Cretaceous of New Mexican section." I have collected it near Mancos, southwestern Colorado, about 400 feet above the 

base of the Colorado Cretaceous shales, where it is associated with 

Ostrea lugubris and Inoceramus dimidius.
174 COLOKADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL. 106.

Genus PPJONOTROPIS Meek. 

PRIONOTROPIS WOOLGARI Mantell (sp.).

PI. XLII, Figs. 1-4. - '

Ammonites woolgari Mantell, 1822, Geol. of Sussex, p. 197, PI. 22, Figs. 6 and 7; Sowerby, 1829, Miu. Couch., vi, p. 25, PI. 587, Fig. 1; Sliarpe, 1853, Fossil Remains 

Moll. Chalk of England, p. 27, PL 2, Figs. 1 and 2, and various other European 

authors; Meek and Hayden, 1861, Proc. Acad. Nat. Sci. Phila.,p. 421.

Prionocyclus (Prionotropis} woolgari Meek, 1876, U. S. Geol. Snr. Terr., vol. ix, p. 455, 

PL 7, Figs, la-h and PL 6, Fig. 2.

Not Ammonites woolgari d'Orh. Paleont. Franc. Terr. Cre"t., vol. i, PL 108, Figs. 1-3.

Ammonites percarinatus, Hall and Meek, 1856, Mem. Am. Acad. Arts and Sci., 2d ser., 

vol. v, p. 396, PL 4, Fig. 2.

Compare A. Iravaisianus and A. carolinus d'Orh., op. cit., PL 91.

Meek's description is as follows:

"Shell attaining a medium size, more or less compressed-discoidal, 

the outer turn being proportionally more convex (including nodes) than 

those within; umbilicus about equaling the greatest dorso-veutral 

diameter of the last turn; each volution embracing about one-fifth of 

the next within, and having its umbilical margin slightly indented by 

the uncovered nodes forming the inner of the two outer rows on the 

succeeding volution within. Young examples, half an inch to one inch 

in diameter, with costae linear, closely arranged, of nearly uniform size, 

and manifesting scarcely any tendency to develop nodes, but already 

showing the forward curve of their outer ends well defined, while the 

peripheral keel is low, narrow, and simple, and the furrow on each side 

s'hallow.. At a somewhat larger size, costae usually more or less unequal 

in size, the larger ones now beginning to develop the two nodes at their 

outer curved ends, and to become a little more prominent and compressed 

at their inner extremities, while the rather more prominent keel begins 

to develop its crenate outline, and the nodes nearest it to assume their 

compressed form and parallel arrangement. On attaining to 2£ to 3 

inches in diameter, costae, nodes, and keel becoming more prominent, 

the latter being strongly compressed and deeply and largely scalloped, with divisions rounded in outline; while at this stage of growth, 

the periphery, as seen in profile, would seem to be very deeply sulcated 

on each side of the keel, but this is due to the prominence of the row 

of nodes on either side of the same. Costae, when the shell has attained a diameter of 4 inches, much depressed in the middle, with 

the nodes at their inner ends thicker and more obtuse, and those nearest the keel more depressed or nearly obsolete, while those of the third 

series, near by, become much enlarged and produced obliquely outward as short, thick, spine-like projections. Soon the outer compressed 

nodes disappear, and the keel is only represented by distinctly separated, low, elongated nodes; and when the shell has attained a diameter of 7 inches, the costse are more distant, greatly elevated, compressed, and almost wing-like, but still retain a large, prominent, sub-
STANTON.] AMALTHEID^E. 175

trigonal node or projection at their outer ends, and again become, as 

it were, pinched up at their inner extremities, which do not quite reach 

the umbilical margin.

" Septa moderately close together; siphonal lobe longer than wide, 

with three or four short branches on each side, the two terminal of 

which are largest, more or less nearly parallel, and merely serrated; 

first lateral sinus broader than the siphonal lobe, more or less deeply 

divided into two subequal branches with short, irregular branchlets 

and digitations; first lateral lobe somewhat longer that the siphonal 

and tripartite, with short, irregular branchlets and digitations occasionally in small specimens, with the middle terminal branch proportionally 

broad and so deeply sinuous at the end as to impart more nearly the 

appearance of a bipartite arrangement of the whole; second lateral 

sinus nearly resembling one of the divisions of the first, and in the 

adult with merely a number of marginal digitations; second lateral 

lobe little more than one-third as long, and from one-third to one-half 

as wide as the first, generally tripartite at the end, but sometimes, in 

large specimens, bipartite on one side of the shell (see Pig. 1/i of our 

PI. 7), the divisions being very short and simple, or serrated; third 

lateral sinus very small and merely bilobate, or in large specimens 

digitate along the margins; third lateral lobe hardly half as long.as the 

second, and in small specimens (it has not been seen in the large ones) 

merely tridentate at the end.

" Largest specimen seen (with a part of the noD septate portion wanting), 7 inches in its greatest diameter; convexity, measuring between 

the costse at the larger broken end of the last turn, l.GO inches; convexity of the same, measuring so as to include the greatly expanded 

costse, 3.25-inches." _

This species was fully illustrated by Prof. Meek (loc. cit.) and copies 

of several of his figures showing some of the stages of development 

are here given. So far as can be determined from the figures and descriptions of Mantell's types there is no reason for separating the American from the English forms, but those figured under the same name by 

d'Orbigny are entirely different, and it seems to me that the forms referred to Ammonites ivoolgari by Schliiter l probably also belong to 

another species. Ammonites Iravaisianus and A. carolinus are probably 

immature specimens of P. woolyari, as Prof. Meek suggested. At least 

they can be exactly duplicated by young individuals of the American 

species. If these really are distinct from Mantell's species I think that 

our species is also different, but this can not be decided until the young 

stages of the English form are more fully known, and all the evidence 

now available supports the opinion that they are identical.

There has been some confusion in regard to the generic relationships 

of this species. Meek 2 made it the type of Prionotropis, which he

0 i Soliliifcer, C., Ceplialop. tl. Qljerep tlcutscli, Kreide, Palseonto^raphica, ypl, xxi, Pis. 9 and 12, 

* Op. cit., p. 453.
176 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL. 106.

regarded as a subgenns of Prionocyclus. When JSTeuuiayr described 

the genus Acanthoccras, he cited A. woolgari 1 as an example of that 

genus, but in the same paper he referred A. bravaisianus, which, may 

be the young of the same species to SchloenbacMa, a genus that as 

originally denned included Prionocyclus and Mortoniceras. In Zittel's 

Handbuch der Paleontologie the same inconsistency is repeated, as A. 

woolgari is listed under Acanthoceras, while both Prionotropis and Prionocyclus are treated as synonyms of Schloenbaehia. On this point in 

a personal letter to the writer, Prof. Alpheus Hyatt says: " The type 

of this genus [Acanthoceras] was in my opinion the Amm. angulicostatus d' Orb. If this be granted, Prionotropis must be considered as the 

type of another genus, since no one having the latest views with regard 

to the Ammonitinae would be apt to place it in the same group with 

Acanth. angulicostatum unless unacquainted with the history of the 

development of the individual in both of these types." Prof. Hyatt 

regards Prionotropis as generically distinct from Schloenbachia and 

Prionocyclus also, although it seems to me to have much closer affinities with the latter genus than with Acantkoceras.

Locality and position. Southeast base of the Black hills. South Dakota, and on the Missouri river 5 miles below the mouth of Yermilion 

river in the Fort Benton shales. It is also reported from the same 

horizon in northeastern Nebraska, in New Mexico, and 8 miles north 

of Fort Lyon, Colorado, and from the Eagle Ford shales in Texas.

In Europe the species seems to be confined to the Turonian.

PRIONOTROPIS HYATTI n sp. 

PL XLII, Figs. 5-8.

Compare Ammonites meeklanus Shumard, 1860. Trans. St. Louis Acacl. of Sci., vol. I, 

p. 592, and Ammonites graysonensis Shumard, ibid., p. 593.

Shell of rather small size, compressed discoidal, consisting of five or 

six whorls; volutions gradually increasing in size, embracing the earlier ones but very slightly so that the umbilicus is broad, though different specimens vary somewhat in this respect. In very young examples the height of the whorls is greater than the breadth, the keel is 

small, and more or less crenate, and the costae are simple, linear, and 

strongly curved forward at the outer ends, without any nodes at first. 

Usually every third or fourth costa is stronger than the others. Some 

specimens three-fourths of an inch in diameter are scarcely distinguishable from the young of Prionotropis woolgari excepting that usually 

the costse are slightly more unequal. As the shell continues to grow 

the inequality of the costse becomes more marked and each of the larger 

ones develops two nodes near the outer end where it curves forward, 

and on some of them there is also an elongated node near the umbilicus..

1 Deutsch. Geol. Gesell. Zeitecjir,, vol, xxvu, 1875, j>. 929,
STANTON.] AMMONITES. 177

At first the two outer nodes are equal, one being just on the angle 

between the side and the abdomen and the other about halfway between 

it and the keel, but at a later stage the nodes nearest the keel become 

obsolete, while the others rapidly increase in size, and some of them are 

developed into prominent sharp spines that are directed obliquely outward and backward. On the outer whorl of the larger example the 

costse becomes distant, apparently by the suppression of the intermediate smaller ones. . While these changes in the surface ornamentation are developing, the 

form of the volution is also considerably altered. The abdomen becomes 

flattened on each side of the narrow? prominent keel, the sides become 

less convex, and the breadth of the whorl is finally almost equal to the 

height, so that its cross section is subquadrate.

The keel in all the larger specimens is usually more or less serrate,

the serration equaling the costse, though sometimes it is only slightly 

sinuous and it is never completely divided into nodes as it is in Prionotropis icoolgari. Septa very much like those of Prionotropis woolgari, 

as is shown by the figures.

None of the specimens show the complete living chamber, but the 

well-developed spines and other features of the surface ornamentation 

seem to be adult characteristics, and it is therefore probable that the 

species never attained a very large size. The largest one before me 

measures 47mm in diameter; the outer whorl is 16mm in height, exclusive 

of the keel, and 15mm in breadth. Some of the spines on specimens of 

this size are 6mm or 7mm long. Some fragments apparently of this 

species belonged to larger individuals.

The development of this species is very much like that of P. woolgari, 

but at the same time it shows many of the features of Prionocyclus 

ivyomingensis.

Ammonites meeJcianus was described from fragments of the outer 

volution of a specimen that seems to have had about the same form as 

our species, but it was much larger than any of the examples I have 

seen. The description of the septum shows-that it had the same general form as in P. hyatti, but the abdominal lobe is said to be broader 

than the first lateral, while the opposite is true in ours. The species 

has never been figured, and there are no specimens of it in the National 

collection.

I have not seen Amm. graysonensis, but judging from the description 

and a figure of one of the types it might be founded on the young of 

either this species or P. woolgari. The types of these two species came 

from near Sherman, Texas, in beds probably equivalent with the Fort 

Benton.

Locality and position. Abundant in the Pugnellus sandstone at many 

localities in Huerfano park, Colorado, where the types were obtained. 

A few specimens were found associated with the same fauna in the 

 "first and second ridges" of the section at Coalville, Utah. 

Bull. 106 12
178 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL. 106.

PRIONOTROPIS? LCEVIANUS White (sp.). 

PI. XLIII, Figs. 3 and 4.

Ammonites Icevianu* White, 1876, U. S. Geos. and Geol. Sur. West 100th Meridian, 

vol. iv, p. 201, PL 19, Figs, la and 6.

Original description:

u Shell moderately large, robust; volutions four or more, increasing 

rapidly in size, especially the outer one, so that the umbilicus is rather 

deep but yet showing all the volutions, each volution embracing between one-quarter and one-third of the width of each preceding one; 

transverse section of outer volution, between the nodes, oval-subquadrate; surface, upon each side, marked by a row of moderately elevated, transversely elongate nodes, situated about one-third of the 

distance from the umbilicus to the dorsum [abdomen]; and also by a 

row of very prominent nodes on each side of the dorsum [abdomen]. 

Each of these rows consists of the same number of nodes. The dorsal 

[abdominal] nodes diverge strongly, but are wholly embraced by each 

succeeding volution, and do not therefore appear in the umbilicus. 

Between these two rows of dorsal [abdominal] nodes, the dorsum [abdomen] is slightly convex, and the outer surface of the shell appears 

to have been marked by a small median cariua. Between these nodes 

and the umbilicus the sides of the volution are broadly convex.

"A greater transverse elongation of the lateral nodes than exists on 

our example would make each continuous with its corresponding dorsal node, which would give to each lateral pair of nodes the character 

of a rib. It is not improbable that this modification may be found to 

exist in some examples of the species.

" Septa complex; dorsal [abdominal] lobe and part of dorsal [abdominal] saddle unknown; superior lateral lobe moderately large, but not 

bifid; inferior lateral lobe small, narrow, not bifid; accessory lobes and 

saddles more or less deeply notched or dentate.

" Diameter of the only example in the collections, the larger part of 

the outer chamber being broken away, 14 centimeters.

" Specific name given in honor of Dr. Oscar Loaw.

"Position and locality. Strata of the Cretaceous period; Ojo de los 

Ouervas, New Mexico."

The type specimen is the only one known that can be positively referred to this species. It is considerably weather-worn on the abdomen, so that the abdominal lobe of the septum is destroyed, and it is 

impossible to say whether the shell had a keel or not. The character 

of the ornamentation and of the septum, so far as it is preserved, suggests relationship with Prionotropis woolgari and it is provisionally 

referred to the same genus. It is considerably more involute than the 

species just mentioned.

Ammonites nodosoides, as figured by Sehliiter,1 resembles this species

'Palasontograpliica, vol. xxi, p. 19, PI. 8.
STANTON.] MORTONICEKAS. m 179

closely. Both it and Ammonites woolgari have been referred to Acanthoceras by some authors, while other species that seem to me related 

to it, such as Amm. michelinianus and Amm.regularis have been assigned 

to Soplites.

P. Icevianus is included in the fauna of the Colorado formation because no Ammonites of the same type are known in higher strata and 

because fragments that are believed to belong to this species have 

been found in the Fort Bentoii shales of Colorado.

Genus MOETONICEEAS Meek.

MORTONICERAS SHOSHONENSE Meek.

PI. XLIII, Figs. 1 and 2.

Morloniceras slios'lionense Meek, 1876, U. S. Geol. Sur. Terr., vol. ix, p. 449, PI. 6, Figs. 

3a, c and 6b.

u Shell compressed-discoidal, with umbilicus' apparently nearly or 

quite twice as wide as the outer whorl; volutions very narrow, with 

dorso-ventral and transverse diameters equal, and section subquadrangular, those within scarcely one-sixth embraced by the succeeding 

turn; costte each mainly represented by two nodes, the inner of which 

is low, compressed, and elongated so as to extend from near the umbilical margin about halfway across the sides, while the outer near 

the peripheral margin are more prominent, rounded, and directed laterally; keel less prominent than the row of compressed nodes on each 

side about halfway between it and the rounded nodes along the margins of the periphery; compressed nodes on the periphery of each inner 

turn covered by the succeeding volution, the inner margin of which is 

indented by the rounded lateral nodes of that next within.

li Septa moderately approximate; siphonal lobe oblong, about once 

and a half as long as wide, with small, short, nearly parallel, serrated 

terminal branches, and three or four very short, digitate, and simple 

brauchlets and points on each side; first lateral sinus wider than the 

siphonal lobe (which it equals in length), unequally bipartite at the 

anterior end, both divisions being digitate, and the larger one on the 

siphonal side deeply bifid; first lateral lobe somewhat longer, but narrower than the siphonal, and having its terminal division deeply bifid, 

a,nd its lateral margins bearing a few very nearly simple branchlets; 

second lateral sinus scarcely more than half as wide as the first, and 

much shorter on the umbilical side, unequally bifid or trifid at the end, 

with more or less sinuous margins; second lateral lobe only about half 

as long and wide as the first, and trilobate, with the small middle division emarginate at the end; third lateral sinus a little shorter and narrower, and irregularly tridentate at the end; antisiphonal lobe about 

as long as the first lateral, but narrower, with a few short, nearly simple, lateral divisions, and a trideutate posterior extremity.
180 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BDLL.IOO.

" Having only a fragment of this species, no measurements of the 

size and proportions of the shell can be given. As this fragment shows 

the form and ornamentation, however, of the volutions, and very clearly 

all of the details of the septa, there will probably be no difficulty in 

identifying it. At one time I was rather inclined to regard it as a 

variety of M. vespertinum Morton; but as the costse in that species 

seem to be very constant in the possession of four nodes each, while on 

the form here described each rib is represented by two nodes, and these 

of different forms, 1 can not believe it the same species.

"Locality and position. Head of Wind river valley, Wyoming; from 

the Fort Bentoii group of the upper Missouri river Cretaceous series."

It is not improbable that this species, and possibly M. vermilionense 

also, is identical with Amm. respertinns Morton ( Amm. texanus Eoem.), 

as Meek suggested, but until other collections are made from the upper 

Missouri localities I prefer to leave them under separate names, giving 

copies of Meek's descriptions.

MOBTONICERAS VERMILIONENSE M. & H.

PI. XLIV, Fig. 1.

Ammonites vermilioncnsis Meek and Hayden, 1860, Proc. Acad. Nat. Sci. Phila., p. 77. 

Mortoniccras vermilionvnse Meek, 1876, U. S. Geol. Sur. Terr., vol. ix, p. 450, PI. 7, Fig. 

2a, 6.

" Shell compressed-discoid, with its shallow umbilicus about one-fifth 

wider than the last turn; volutions increasing'gradually in size, with 

convexity about three-fourths the dorso-ventral diameter, each turn 

less than one-fifth embraced by the succeeding outer one; costse simple 

and closely arranged in the very young shell, but gradually becoming 

larger, more distant, and a little thickened at their inner and outer 

extremities, which latter are slightly curved forward, in examples an 

inch or so in diameter; peripheral keel moderately prominent, with the 

depression on each side shallow.

"Septa not crowded; siphonal lobe oblong, about one-fourth longer 

than wide, with two short, narrow, equal or subequal, nearly simple 

lateral branches, the two terminal of which are diverging and moderately distant; first lateral sinus as long and nearly twice as wide as 

the siphonal lobe, and deeply divided into two nearly or quite equal 

parts, with merely sinuous and obtuse digitate margins; first lateral 

lobe slightly longer than the siphonal, and of about the same breadth, 

with some five or six spreading, unequal digitations at the posterior 

end, the middle two of which sometimes become more prominent, so as 

to give a slightly bifid appearance to the extremity; second lateral 

sinus short, or scarcely more than half as long on the inner side as the 

first, subquadrate in form, with shallow marginal sinuosities; the mesial 

very shallow indentation, causing a faint tendency to a bilobate outline at the anterior extremity; second lobe very small, or even less 

than the auxiliary lobe of the first lateral sinus, about twice as long as
STASTON.I STEPHANOCERATID2E. 181

wide, narrower, and truncated at its posterior end, with a very few 

shallow sinuosities along its lateral margins; third lateral sinus hardly 

half as long or wide as the second, and merely faintly bilobate at the 

end; third lateral lobe a little oblique, simple, and smaller than one of 

the principal terminal digitations of the first lateral lobe.

"Greatest diameter, 1.10 inches; convexity, about 0.26 inch.

" The little specimen from which the foregoing description was made 

out is doubtless a young shell. If not, it would not properly go into 

the group Mortoniceras, as its costee and periphery are without nodes; 

the former being also more curved forward at their outer ends than is 

usual in the typical species of the same. Its costs®, however, on the 

outer volution show rather a distinct thickening at both extremities, 

and it is very probable that in larger adult individuals distinct nodes 

are developed. The lobes and sinuses of the septa would doubtless at 

that size be found more deeply divided and branched.

" It is on the supposition that this shell is a young example, in which 

the usual characters of the group Mortoniceras have not beeu fully developed, that I here refer it to that group. It might even be a young 

of the last, or of M. vesperlinum.

"It is evidently not a young specimen of Prionotropis ivoolyari, as its 

costse are broader and decidedly straighter than those of that species 

of the same size, and show no traces of. the double node usually seen 

at their outer ends, even in smaller examples of the same; while its 

keel is also without the obscure crenulations of that shell, and the 

volutions less compressed. It is true that the crenulations of the keel 

in specimens of P. woolgari of this size are not well developed; but 

traces of them can usually be seen near the larger extremity of the 

outer turn at that stage of growth.

"Locality and position. Mouth of Vermilion river, Nebraska, on the 

Missouri; where it was found in the Fort Ben toil group of the upper 

Missouri Cretaceous series."

STEPHANOCERATID^E. 

Genus ACANTHOCEKAS Neurnayr.

ACANTHOCEKAS 1 KANABENSE 11. Sp.

PI. xxxvi, Figs. 6-8.

Shell discoidal with convex, slightly embracing whorls whose breadth 

is greater than the height; umbilicus about equal to the shorter diameter of the outer whorl; abdomen broad and gently convex with three 

rows of closely arranged rounded nodes, one on the median line and the 

others on either side half way between it and the peripheral margin. 

On the outer whorls the nodes of the median row tend to unite into a 

low keel. Sides of the whorl somewhat flattened; costai on the earlier 

whorls numerous, angular, unequal in size and strongly curved forward in passing from the umbilicus to their termination at the outer 

rows of the abdominal nodes. On about the second whorl a few nodes
182 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL. 106.

begin to develop near the umbilical margin and a larger number of 

stronger ones form a row near the peripheral margin. Occasionally two 

costse unite at one of these outer nodes and again divide on leaving it. 

As the shell grows the smaller costee disappear and the larger ones 

become rounded and less prominent until on the outer whorl of specimens an inch and a half in diameter each is represented by two large 

round nodes. At this stage there are about twice as many nodes in 

each row of-the abdomen as there are in the row near the peripheral margin, so that all the suppressed costse are apparently still represented 

by nodes on the abdomen.

Septa not very complex; the lobes all bipartite and the saddles more 

or less distinctly [tripartite at their extremities. Abdominal lobe large 

and rather slender, being nearly twice as long as broad; first lateral 

saddle about the size of the abdominal lobe; superior lateral lobe much 

broader than the first lateral saddle, deeply bifid; inferior lateral lobe 

and saddle with the forms of those just described but much smaller. 

There are one or two very small auxiliary lobes and saddles.

The type specimens are three young shells and two fragmentary 

older ones, all of which are septate throughout. The largest specimen 

gives the following measurements: Diameter, 49mm ; height of outer 

volution, 16mm ; breadth of same, 26m'n .

This species seems to fall into the genus Acanthoceras, as defined in 

Zittel's Handbuch der Paleontologie, though that genus is made to 

include a number of groups.that are apparently not very closely related. 

Acanthoceras angulicostatum, which may be regarded as the type of the 

genus, is certainly very different from our form. The latter seems to 

be related to Amm. coleroonensis Stoliczka.1 The suture is of the same 

character and the form as shown in the small specimen (Fig. 4 of same 

plate) is quite similar, though there is uo abdominal keel and the coste 

pass entirely across the abdomen.

Locality and position. Upper Kanab, Utah, about 350 feet above the 

base of the Cretaceous section. Another specimen collected from the 

Austin limestone near New Braunfels, Texas, belongs to the same or a 

closely related species.

Genus SOAPHITES Parkmson.

SCAPHITES LARV^EFORMIS Meek and Hayden.

PL XLIV, Fig. 2.

ScapMics larvceformis Meek and Fayden, 1856, Proc. Acacl. Nat. Sci. Phila., p. 58; 

Meek, 1876, U. S. Geol. Sur. Terr., vol. ix, p. 418, PI. vi, Figs. 6a, I, c.

Eevised description

" Shell small, transversely subovate, compressed, evenly rounded on 

the periphery; volutions slender, nearly round, the inner or coiled ones 

forming only a very small part of the entire shell, and so closely involuted as to leave only a very small umbilical pit; extended body-portion

1 Fossil Cephalopoda of Soutliei n India, PL xxxvn.
BTAXTON.] STEPHANOCERATID^S. 183

ratlier long, slender, and straight to the recurvature, thence continued 

backward until it comes nearly in contact with coiled inner volutions; 

aperture apparently circular; surface ornamented by small costne, 

which pass from the inner side of the volutions to about halfway 

across their lateral surfaces, where they swell into small, obscure, 

transversely elongated nodes, and then branch each into two or three 

smaller linear ribs, all of which pass straight over the periphery.

"Length, 0.87 inch; height, 0.63 inch; convexity, 0.33 inch.

"The septa of this species are comparatively rather simple, being 

each provided with but two principal lateral lobes on each side, none 

of which are deeply divided. The siphonal lobe is longer than wide, 

and has two very small, short, nearly parallel, obscurely bifid terminal 

divisions, with a more oblique, somewhat similar branch on each of the 

sides above. The first lateral sinus is wider than the siphonal lobe, 

and nearly as long, with its extremity deeply divided by a slender, 

obscurely triiid, auxiliary lobe, into two very unequal, more or less 

sinuous, and obtusely digitate branches. First lateral lobe about half 

as wide as the siphonal, but somewhat shorter, and bearing two very 

small terminal divisions similar to those of the siphonal lobe. Second 

lateral sinus not larger than the outer division of the first, and merely 

obscurely divided into very short, simple, obtusely rounded terminal 

subdivisions. Second lateral lobe very small and obscurely trifid at 

the end. Whether this last is what is usually called a ventral lobe, or 

whether there is another still smaller'one beyond it, the specimen is 

'scarcely in a condition to show.

"At one time I was inclined to think a very small species described 

by Dr. Shumard from the Cretaceous rocks of Texas, under the name 

Scapliltes vermiculus, might be identical with this; but a sketch of that 

species sent to me some years back by Dr. Shumard shows it to be 

entirely distinct, being even a more slender, differently marked shell, 

with a proportionally much larger umbilicus and a longer deflected 

body-portion; that is to say, it presents the characters of the distinct 

section Macroscaphites.

"This species is perhaps more nearly allied to 8. Hugardianus 

d'Orbigny,1 than to any other foreign form, but yet differs too much to 

require a critical comparison or detailed statement of differences.

u Locality and _p(miMW. Eastern base of the Black hills; from the 

Fort Beutou group of the upper Missouri Cretaceous series."

SCAPHITES VERMIFORMIS Meek and Hayden. 

PI. XLIV, Fig. 3.

ScapTiites venni/ormis Meek and Hayden, 1862, Proc. Acad. Nat. Sci. Phila., p. 22; 

Meek, 1876, U. S. Geol. Sur. Terr., vol. ix, p. 423, PL 6, Figs. 4«, I.

Revised description:

"Shell under medium size, ovate .subcliscoidal in form; umbilicus 

very small; inner regularly coiled volutions closely involute, deeply

'Pal. Fr., 1, Terr. Cr6t., 525.
184 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [Buu,io6.

embracing and composing a rather large portion of the entire shell; 

deflected part very shortj so as only to be slightly disconnected from 

the inner turns at the aperture, which is a little contracted and quadrato-subcircular in outline, with a slightly sinuous inner margin; 

surface ornamented by numerous straight costse, which are rather 

small and nearly regular on the inner volutions, but become more 

distant and larger, as well as much more prominent, on the inner half 

of each side of the body-portion, where they each support a prominent 

node at the outer end, so arranged that those on opposite sides generally alternate; costse all passing nearly straight across the periphery, 

on which they are of nearly uniform size, with the exception of their 

regular enlargement with the whorls.

"Thenodes mentioned above are directed out at right angles to the 

sides of the shell, and, like the costee, become again smaller toward the 

aperture. Most of the large costse bifurcate at the nodes on the bodypart of the shell, but their number is also increased by the intercalation 

of others between. Where they thus branch at the nodes on one side, 

the two divisions crossing over the periphery from the point of bifurcation never both connect at a node on the opposite side, but in most 

cases one, and sometimes each division, terminates between two of the 

nodes on the other side.

"The septate portion of the only specimen of this species in the col. 

lection being highly crystalline, the structure of its septa can not be 

very clearly traced out. The siphonal lobe, however, can be seen to be 

a little longer than wide, with a rather narrow body, provided with 

three branches on each side, the upper pair of which are small and 

nearly simple; while the next pair are longer and each bifid, and the 

terminal pair (which are larger than the second) are each ornamented 

by three small, pointed branchlets, or digitations, on the outer side. 

The first lateral lobe is',somewhat irregularly tripartite; the lateral 

divisions being bifid and sharply digitate, while the terminal, which 

is not exactly central, is longer than the others and has about five 

pointed digitations, or sharp, nearly or quite simple, branchlets. The 

first lateral sinus can be seen to be deeply divided at the extremity into 

two nearly equal branches. The second lateral sinus can also be so far 

traced as to show that it is not more than about one-third as large as 

the first, nearly as long as wide, and regularly tripartite; and this is as 

far as the structure of the septa can be made out from the specimen.

"Length, 2.10 inches; height, 1.76 inches; greatest convexity,measuring to the extremities of the nodes on opposite sides, 1.25 inches; 

same between the nodes, 1 inch.

"This species is somewhat related to S. hippocrepis Dekay, sp. 

(=Ammonites hippocrepis Dekay 1 ), but differs in having its body-part 

less extended, and in being higher in proportion to its length. Its 

nodes are also larger and much more prominent; but the most marked

1 Ann. N. Y. Lyceum, Nat. Hist., n, PI. v, Fig. 5.
STANTON.] STEPHANOCERATID^E. 185

differences between these two forms are in their septa, the siphonal 

lobe of the form under consideration being proportionally much narrower, and provided with three, instead of only two, branches on each 

side, while its first lateral lobe is tripartite (an unusual feature in the 

genus) instead of bifid. It is also related to 8. Texanus Eoeuier,1 

though its septa differ as widely from those of that species as from 

those of 8. hippocrepis.

"Locality and position, Chippewa point, near Fort Benton, on the 

upper Missouri; from the Fort Benton group of the upper Missouri 

Cretaceous series. Specimen discovered by Lieut. John Mullan, of the 

United States Topographical Engineers."

SCAPHITES WARRENI Meek and Hayden. 

PI. XLIV, Figs. 4-7.

Scapllites warreni Meek aud Hayden, 1860, Proc. Acad. Nat. Sci. Phila., p. 177; White, 

1876, U. S. Gcog. aud Geol. Sur. West 100th Meridian, vol. rv, p. 200, PL 19, Fig. 

3a; Meek; 1876, U. S. Geol. Sur. Terr., vol. ix, p. 420, PI. 6, Fig. 5; Whitfield, 1880, 

Geol. Black Hills of Dak., p. 444, PI. 13, Figs. 1-4.

Scaphites warreni, var. wyomingensis Meek, 1876, ibid., p. 421, Fig. 61-63 in text.

Scapllites rvyomingensis Whitfleld, 1880, ibid., p. 446, PI. 13; Figs. 5-7.

Compare Scapllites cequalis Sowerby.

Meek's description of the type is as follows:

" Shell small, transversely subovate, moderately compressed; inner 

volutions nearly circular, closely involute, and composing a comparatively rather large part of the entire bulk; deflected body-portion short 

and (perhaps accidentally) rather more compressed proportionally than 

the inner turns; surface costate, and without proper nodes; costaj small 

on the inner volutions, where they do not differ materially in size, but 

on the body-part about every fourth or fifth one'becomes more prominent than the others, and extends entirely across from the inner side 

to and over the periphery, in passing upon which they bifurcate, or 

give off lateral branches, so that the whole, with some intercalated 

ones, assume there a uniform size; aperture and septa unknown.

"Length, 1.45 inches; height, about 1.22 inches; convexity, about 

0.57 inch."

The type is an imperfect specimen that does not show the entire form 

nor the septa. Afterward other examples were found that showed 

these details and that differed slightly from the type in form and surface ornamentation, so that they could not be positively identified with 

it, and Mr. Meek therefore called them Scaphites icarreni, var. Wyomingcnsis.

Mr. .Whitfield regarded this variety as a distinct species, assigning 

to it the smaller specimens with more compressed volutions. In discussing its relations with 8. warreni lie says: "The principal differ-

 Kreid. von Texas, tab. 1, Fig. 4.
186 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL. 100. < 

ences, therefore, between the two shells, and those which we deem of 

specific importance, are the greater length of the deflected part, the 

laterally compressed form of the volution, and the different direction of 

the costae on the straight part of the shell. The two forms are associated at the same localities, and even occur in the same hand specimen -^ 

of rock, but we think there is no difficulty in distinguishing them."

The septa of the two forms are essentially tbe same, the only difference being that those of the small specimens assigned to 8. wyomingensis are slightly less complex. In all of them the septa are much more 

'simple than in most species of the genus. The differences do not seem 

to me great enough, nor constant enough to warrant the reference of 

these forms to distinct species, especially when we remember that they 

are associated in the same stratum. Other species of Scaphites, such 

as S. nodosus, certainly show greater variations. For comparison, copies 

are given of Meek's figure of the type of iS. icarreni and of Whitfield's 

figures of S. warreni and S. 'wyominycnsis. After careful comparison of 

this species with Scaphites cequalis Sowerby, of the European Cenomanian, Prof. Meek regarded them as very closely allied.

Locality and position. The type came from the southern base of the 

Black hills of Dakota, where it was found in the- Fort Ben ton shales. 

It has been collected from the some horizon at many localities in Wyoming, Dakota, Colorado, New Mexico, and Utah. \

/- 

SCAPHITES VENTRICOSUS Meek & Hayden. 

PL XLIV, Figs. 8-10; PI. XLV, Fig. 1.

SccvpMtes ventricosus Meek &. Hayden, 1862, Proc. Acad. Nat. Sci. Philn., p. 22; Meek, 

1876, U. S. Geol. Stir. Terr., vol. ix, p. 425, PI. 6, Figs. 7 a, & ami 8 a, b.

Revised description:

" Shell attaining a medium or larger size, oval, ventricose, broadly 

rounded over the periphery; inner turns closely involute, deeply embracing, and composing a large portion of the entire bulk; deflected 

portion very short; umbilicus very small and deep; aperture transversely sublunate or reuiform, but deeply sinuous, and but slightly disconnected from the inner turns on the inner sidej surface ornamented 

with costae that pass nearly straight over the periphery, where they are 

of uniform size, excepting their gradual enlargement with the volutions, 

while on the sides of the last or outer volution, about every fifth or sixth 

one is larger and more prominent than the intermediate ones, which 

latter do not extend inward to the umbilical margin. A

" The septa, as made out from the specimen represented by our figures 8a, & (believed to be the inner volutions of this species, as repreresented by figures 7a, &) are provided with deeply divided lobes and 

sinuses. Siphonal lobe longer than wide, and bearing on each side of ' 

its very slender body three branches, the two terminals of which are 

slightly larger than the succeeding lateral ones, and each unequally
STANTON.] STEPHANOCERATID.E. 187

 bifid and digitate; first lateral sinus as large as the siphonal lobe, very 

narrow at its base, and profoundly divided at its extremity into two 

unequal brandies, of which the one on the siphonal side is larger than 

the other, and, like the latter, deeply bifid, with sinuous and obtusely 

digitate margins; first lateral lobe as^wide as the siphonal lobe, but 

somewhat shorter, and provided with two nearly equal, bifurcating, and 

digitate terminal branches; second lateral sinus not more than half as 

long, and little more than half as wide as the first, and somewhat similarly divided and subdivided; second lateral lobe about half as' long 

and wide as the first, but tripartite at the extremity, the divisions being 

nearly equal and digitate; third lateral sinus small and merely provided with two nearly equal terminal branches, with more or less sinuous margins; third lateral lobe hardly more than half as large as the 

second, and bearing two very short, digitate, terminal divisions, Between the last-mentioned lobe and the umbilicus there is a minute, tridigitate lobe, very similar to the auxiliary lobe of the third lateral 

sinus, but smaller.

"Length, 3.13 inches; height, 2.65 inches; convexity, 1.90 inch.

"In the style of its ornamentation this species resembles our S.Warreni, but it differs, however, remarkably in form, and size, being much 

larger, and proportionally very decidedly more gibbous, with a proportionally smaller umbilicus. As the septa of the type of 8. warreni are 

yet unknown, I have not had an opportunity to compare their structure with those of the form under consideration; but it is probable 

that they will be found to present differences in their details. Certainly those of the Wyoming form, that I now regard as only a variety 

of S. warreni, are quite different."

Locality and position. Chippewa point on the upper Missouri river, 

Fort Beiitou shales.

SCAPI-IITES MULLANANUS Meek & Haycleu (sp.). 

PI. XLV, Figs. 2-4.

Ammonites mnllananus Meek &, Hayden, 1862, Proc. Ac.ad. Nat. Sci., Phil a., p. 63. 

Ammonites?? mullauauus Meek, 1876, U. S. Geol. Sur. Terr., vol. ix, p. 607, PI. 8, Figs.

la-c. 

Compare Scapldtcs sulxjlobosm Whiteaves, 1885, Gout, to Can. Palaeont, vol. I, p. 52, PI.

7, Fig. 3 and PI. 8.

Meek's revised description is as follows:

" Shell compressed-subglobose; rounded on the periphery; umbilicus 

small, deep, and acutely conical, between one-third and one-half as 

wide as the breadth of the outer whorl from the dorsal to the ventral 

side, showing about one-third of each inner volution. Whorls increasing rather rapidly in size, particularly in convexity, sloping on each 

side from near the umbilicus (with a slightly convex outline) toward 

the periphery, and roundiug abruptly into the umbilicus on the inner 

side, each of those within deeply embraced by the succeeding turn.
188 COLORADO FORMATION AND ITS INVERTEBRATE FAUNA. [BULL. 106.

Aperture transversely reuiform or sublimate. Surface ornamented by 

rather small, regular, rounded costse, which pass nearly straight across 

the sides of the whorls, and arch slightly forward in crossing over the 

periphery, on which from thirty-six to forty of them may be counted to 

every turn; each of those commencing at the umbilicus, usually there 

a little enlarged, especially on the larger whorls, so as to form a small 

subnodose prominence. Beyond these they all (particularly on the 

inner whorls) bifurcate regularly once, near the middle of each side, 

and on the larger turns others are also intercalated between, so as to 

make the number on the peripheral side five or six times as great as 

at the umbilicus.

"The septa are rather,crowded, and provided with branched and 

deeply sinuous lobes and sinuses. The siphonal lobe is about one-fourth 

longer than wide, nearly obovate in form, and ornamented Avith three 

principal branches on each side, the two terminal of which are larger 

than the others, and each provided on the outer side with two or three 

more or less digitate lateral branchlets, while the inner parallel margins are merely sharply serrated. The first lateral sinus is of about 

the same size as the siphonal lobe, a little oblique, nearly oblong in 

form, and divided at the extremity into two tripartite and obtusely 

digitate branches, of which the one on the outer side is larger than the 

other; behind these it is provided on each side with two alternating 

lateral branches with sinuous margins. The first lateral lobe is narrower and shorter than the siphonal lobe, and provided with two principal branches on each side, the two terminal of which are much larger 

than the others, and of unequal si/e, the one on the right or peripheral 

side being the larger. Both of these terminal branches are distinctly 

bipartite, the subdivisions being ornamented with several branchlets

and smaller digitations. The second lateral sinus is about half as wide 

and nearly two-thirds as long as the first, more or less oblique, and 

rather deeply divided at the extremity into two subequal, bifurcating, 

and obtusely digitate terminal branches. The second lateral lobe is as 

long as the second lateral sinus, but a little narrower, and ornamented 

with three variously digitate terminal branches, the middle one of 

which is longer than the others, a little oblique, and not exactly central. The third lateral lobe is small, being less than half as long, and 

scarcely two-thirds as wide as the second lateral, and provided with 

three nearly equal, spreading, digitate, terminal branches. Between 

the third lateral lobe and the umbilical margin there are two other 

small, very unequal, lateral lobes, the first of which has two or three 

digitations on each side, while the second is nearly simple or but 

slightly sinuous on the margins."

The only examples of this species I have seen are the types, consisting of the specimen figured and a septate fragment of a much larger 

individual. As the body chamber is lacking these do not show whether 

the species had its last volution deflected and separated from the rest 

of the shell, still its apparently close relationship with Scapliltes ven-
STANTOH.] ARTHROPOEA. 189

tricosus, as shown by similarity in form and in the character of the septa, 

seems to justify its reference to the same genus.

Scaphites sufogloltosus Whiteaves is probably identical with this species. The types of 8. mullananus agree with the figures of 8. subglobosus in every respect excepting that they do not show the small nodes 

near the periphery. The latter is reported from the " East Branch of 

the Poplar river, on the 49th parallel," where it is said to occur in the 

equivalents of the Montana formation.

Locality and position. " Ohippewa point, near Fort Benton, on.the 

upper Missouri; Fort Benton group of the upper Missouri Cretaceous 

series."

ARTHROPODA.

CRUSTACEA.

A few fragments of the legs of a decapod crustacean were found in 

theJPugnellus sandstone at Poison canyon, Huerfano park, Colorado. 

They do not show either the generic or specific characters and they are 

mentioned here simply to record the rare occurrence of crustacean 

remains in this formation.

PLATES.

191

PLATE I.

193 

Bull. 106 13
PLATE I.

Pape.

SERPTJLA INTRICA White....................................:............... 53

Fig. 1. Copy of White's figure of the type. 

SERPULA TENUICARINATA M. and H......................................... 53

Fig. 2. View of the typo specimen (after Meek).

OSTREA PRUDENTIA White .................................................. 54

Figs. 3,4. Opposite views of one of the types (after Wliite). 

OSTREA ANOMIOIDES Meek.................................................. 55

Fig. 5. Lower valve (after White). 

6. Upper valve (alter White).

194
U. S. GEOLOGICAL SURVEY BULLETIN NO. 106 PL. I

SERPULIDXE AND OSTREID/E.
PLATE II.

195
PLATE II.

Tage.

OSTKEA SOLTCNTSCUS Meok.................................................. 56

Fig. 1. Upper view of a small example partly restored (after White). See

additional figure on Plate III. 

OSTREA CONGESTA Conrad.................................................. 55

Figs. 2,3. Interior views of upper valves slightly enlarged (after Meek). V. 

4. Three small lower valves attached to the shell of a la.rge Inoceramus \ 

(afte'r Meek).

OSTREA MALACI11TENSIS n. Sp. ........................................... 57

Nat. Mus. Cat. Invert. Foss., 22857.

 Figs. 5, 6. Lower valves of somewhat less than average size. 

7, 8. Opposite views of an upper valve.

1C6
U. S. GEOLOGICAL SURVEY BULLETIN NO. 106 PL. II

OSTREID/E.
PLATE III.

197
PLATE III.

Page.

OSTREA SOLENISCUS Meek ................................................... 56

Figs. 1,2. External views of two broad exogyrate upper valves associated 

with the slender variety at Bear KiArer city, Wyoming, and believecl to belong to the same species. See Fig. 1 of Plate n.

OSTREA UNIFORMIS Meek ................................................... 59

Figs. 3,4. Two views of the lower valve of the type (after White).

198
U. S. GEOLOGICAL SURVEY BULLETIN NO. 106 PL. Ill

OSTREID/E.
PLATE IV.

199
PLATE IV.

Page.

OSTREA LUGUBRIS Conrad.................................................... 58

Fig. 1. A small lower valve from eastern New Mexico. Conrad's type specimen. \

Nat. Mus. Cat. Invert. Foss., 9822. 

2. A small upper valve from Huerfano park, Colorado.

Nat. Mus. Cat. Invert. Foss., 22860.

3,5. External and internal views of small lower valves from Mancos, 

Colorado.

Nat. Mus. Cat. Invert. Foss., 22859.

4,6. Lower valves from Huerfano park, Colorado.

Nat. Mus. Cat. Invert. Foss., 22860.

7. A large lower valve from 20 miles above Pueblo, Colorado. 

Nat. Mns. Cat. Invert. Foss., 22861.

8. A small lower valve of Ostrea lellaplicata from near Shenriari, Texas, 

for comparison. Nat. Mus. Cat. Invert. Foss., 11882. ..:

9. Interior of lower valve from Huerfano park, Coloracltfr

10. Cast of interior of upper valve from same region. 

Nat. Mus. Cat. Invert. Foss., 22860.

200

-A.
U. S. GEOLOGICAL SURVEY BULLETIN NO. 106 PL. IV

OSTREID/t.
PLATE V.

201
PLATE V.

Pn£p.

NEWBERRYI n. sp................................................. 60

Figs. 1, 2, 3. Different views of a small lower valve (after White).

4, 5. Opposite views of a large specimen with both valves united. 

Nat. Mus. Cat. Invert. Foss., 8775.

EXOGYRA SUBORBICULATA Lain ............................................ 62

Fig. 6. Lower valve retaining a portion of the shell. 

(See Pis. vi and vjn for additional figures.) 

 Nat. Mus. Cat. luvert. Foss., 22862.

202
U. S. GEOLOGICAL SURVEY BULLETIN NO. 106 PL. V

OSTREID/E.
PLATE VI.

203
PLATE VI.

Pago. 

EXOGYRA SUBOKBICTJLATA Lam....... ..............................__.... &2 \_

Fig. 1. Posterior view of the specimen represented by PI. v, Fi<j. 6.

2. Cast of another large lower valve. (See Pis. v and vixilbr additional 

figures.)

Nat. Mus. Cat. Invert. FOBS., 228G2.

204 -
U. S. GEOLOGICAL SURVEY BULLETIN NO. 106 PL. VI

OSTREIOC.
PLATE VII.

205
... PLATE VII.

 Page. 

EXOGYRA PONDEROSA Roemcr .............................................. 65

Figs. 1, 2. Opposite views of a. specimen from southern Utah (after White).

206
U. S. GEOLOGICAL SURVEY BULLETIN NO. 106 PL. VII

OSTREID/E.
PLATE VIII

207
PLATE VIII.

 Page. 

EXOGYRA SUBORBICULATA Lam. .... ............................ ............ 62 \

Fig. 1. Fragment of an upper valve.

Nat. Mns. Cat. Invert. Foss., 22863.

EXOGYRA COLTJMBELLA Meek ........................'....................... 63

Fig. 2. Dorsal view of a large lower valve (after White).

3. Side view of lower valve (after White).

4. Upper view of specimen with both valves united (after White). 

EXOGYRA L^EVIUSCULA Roemer ............................................. 64

Figs. 5,6. Different views of lower valves (after White). / '\ 

ANOMIA CONCENTRICA Meek ................................................ 67 ' . 

Fig. 7. View of Meek's type specimen.

Nat. Mus. Cat. Invert. Foss., 489. 

ANOMIA SUBQUADRATA n. sp................................................ 66

Figs. 8, 9. Casts of two upper valves retaining portions of the shell, and 

showing the variation in outline and convexity. 

Nat. Mus. Cat. Invert. Foss., 22864. 

ANOMIA PROPATORIS White?................................................ 67

Fig. 10. Upper valve slightly enlarged.

Nat. Mus. Cat. Invert. Foss., 22865.. 

PLACUNOPSIS? HILLIARDENSIS White........................................ 68

Fig. 11. View of the type specimen (after White).

208
U. S. GEOLOGICAL SURVEY BULLETIN NO. 106 PL. VIII

OSTREID/E AND ANOMIID/C.
PLATE IX.

Bull. 100 14 209
PLATE IX. V . .

 "< Page. 

PLJCATULA HTDROTHECA White................... T ...............".,........- 69

Figs. 1, 2. Views of the opposite valves (after White),

PLICATULA ARKNARIA Meek;.. .-.,.. ,,... ,......... ,,........;,,........... 70

Figs. 3,4. Views of the under and upper valves (after Meek). 

LIMA UTAHENSIS n. sp-..,. - ,.---,--,.....,,-.,-.-, ..-....,..,. .......... 71

Fig. 5. Cast of a large left valve,

Nat. Mus. Cat. Invert. Foss., 22942. C 

CAMPTONECTES PLATESSA White............... 1 ,..,.. ,,...,.............. 72

Fig. 6. Eight valve of the type (after White). 

AVICULA GASTRODES Meek.....,.,.,...............,.,..,..,..,. ............ 72

Nat. Mus. Cat. Invert. Foss., 22866.

Fig. 7. Large left valve restored from two specimens which together show all 

the features drawn.

8. A small left valve.

9. 10. Two views of a more oblique specimen

210
U. S. GEOLOGICAL SURVEY BULLETIN NO. 106 PL. IX

SPONDYLIDXE LIMID^E PECTINID/E AND AVICULID/E.
PLATE X.

211
PLATE X.

Page.

GKKVTLLIA PROPIETTOAMeek........................:...................;.... 74

Fig. 1. A small oblique left valve; one of Meek's types (after White).

2. Left valve of an adult less oblique example; Meek's type of Avicula 

(Pseudoptera) rhytophora (after White).

3. An imperfect cast of a left valve retaining a portion of the shell, from 

Huerfano park, Colorado.

Nat. Mus. Cat. Invert. Foss., 22876. . . 

INOCERAMUS LABIATUS Schloth............................................. 77

Fig. 4. Right valve of an elongated specimen (after Meek). (See PI. xiv,

Fig.l.) 

INOCERAMUS DIMIDIUS White... ......^.................................. ^ 78

Fig. 5. Left valve of a specimen of average size (after White).

6. Front view showing convexity of both valves (after White).

213
U. S. GEOLOGICAL SURVEY BULLETIN NO. 106 PL. X

AVICULID/E.
PLATE XI.

213
PLATE XL

J»flgfi. 

INOCERAMTJS FRAGILIS H. & M.............................................. 76

Fig. 1. Eight valve of one of Whitiield's types of Inoceramus perplexus. \ 

Nat.Mns. Cat. Invert. Foss., 12274.* -

2. A larger right valve (after Meek).

3,4. Two views of one of- the types of Inoceramus howelli (after White).

5. A large example selected from the types of /. howelli to show variation in form. 

Nat. Mus. Cat. Invert. FOBS., 8052.

214
U. S. GEOLOGICAL SURVEY BULLETIN NO. 106 PL. XI

AVICULID/E.
PLATE XII,

215
PLATE XII.

Page.

INOCERAMUS siMPSONi Meek..................................__....... 79

Fig. 1. Eight valve of the type specimen (after Meek).

216
U. S. GEOLOGICAL SURVEY BULLETIN NO. 106 PL. XII
PLATE XIII.

217
PLATE Xiil.

Pays.

FLACCTDTTS White.... . .............................. * i4 i.._ 80

Fig. 1. Left valve of type (after White).

ais
U. S. GEOLOGICAL SURVEY BULLETIN NO. 106 PL. XIII

AVICULID/E.
PLATE XIV.

219
PLATE XIV. '

, Pap"

INOCERAMUS DEFORMIS Meek....... .................................... .... 85

Fig. 1. Anterior view of small specimen. (See PI. xv.)

Nat. Mus. Cat. Invert. Foss., 21119. . 

INOCERAMUS LABIATUS Schloth............................................. .77 y

Fig. 2. Small right valve with unusually strong concentric ridges. (See PL / 

x, Fig. 4.)

Nat. Mus. Cat. Invert. Foss., 22868. 

INOCERAMUS GILBERTI White.. ....__... ........................ 79

Figs. 3,4. Two views of a left valve (after White). .

220
U. S. GEOLOGICAL SURVEY BULLETIN NO. 106 PL. XIV

AVICULID/E.
XV. PLATE 

221
XV. PLATE 

Page.

85 Meek......................i.............i.......... DEFORMIS INOCERAMUS 

1. Fig. xiv, PL by represented specimen small the of view Another 1. Fig. 

Meek). (after valve right larger A 2. 

222
U. S. GEOLOGICAL SURVEY BULLETIN NO. 106 PL. XV

AVICULID/E.
PLATE XVI.

323
PLATE XVI. 

INOCERAMUS UNDABUNDUS M. & H......................................... 8d

Figs. 1,2. Two views of a left valve (after Meek). 

INOCERAMUS TENUIBOSTRATUS M. &H...................................... 83 \

Figs. 3,4. Two views of the type specimen. V 

Nat. MUB. Cat. Invert. Foss., 1906.

224
U. S. GEOLOGICAL SURVEY BULLETIN NO. 106 PL. XVI

AVICULID/E.
PLATE XVII.

Bull. 106 15 225
PLATE 

INOCERAMUS EXOGYROIDES M. & H..................... i................ 83

Figs. 1,2. Two views of an internal cast of the left valve (after Meek),

226 ' .
U. S. GEOLOGICAL SURVEY BULLETIN NO. toe PL. xvii

AVICULID/E.
PLATE XVIII.

227
PLATE XVIII.

Page.

INOCERAMUS UMBONATUS M. & H......................... ............... 81

Fig. 1. Dorsal view'of a cast of a left valve reduced in size (after Meek). 

2. Anterior view of a cast of a left valve, retaining portions of the 

fibrous layer of shell in the umbonal region (after Meek).

228
U. S. GEOLOGICAL SURVEY BULLETIN NO. 106 PL. XVIII

AVICULID/E.
4 PLATE XIX. .

229

k
PLATE XIX.

Pago.

TRIGOITARCA OBLIQUA Meek ................................................ 92

Pig. 1. Left valve of a short broad specimen, showing traces of radiating 

lines on the posterior region. (See other figures on PI. xx.)

Nat. Mus. Cat. Invert. Foss., 22869. 

TRIGONARCA DEPBESSA White.............................................. 93

Fig. 2. Right valve of the type specimen. . \ 

Nat. Mus. Cat. Invert. Foss., 8645. . - 

MODIOLA (BRACHYDONTES) MULTILINIGERA Meek..... ..........;........ 86

Fig. 3. Left valve (after White). ' 

PINKA PETRINA White...................................................... 88

Fig. 4. Right valve of the type of Pinna stevensoni. (See PI. xx, Fig. 1.) 

Nat. Mus. Cat. Invert. Foss., 8101.

230 ,
O. S. GEOLOGICAL SURVEY BULLETIN NO. 106 PL. XIX

MYTILID/E, PINNID/E AND ARCID/C.

PLATE XX.

Page.

PINNA PETRIWA White...... ....................... ........ ....... 88

Fig. 1. Left valve of the type specimen. (See PI. xix, Fig. 4.)

Nat. Mus. Cat. Invert. Foss., 8640. 

TIUGONARCA OBLIQUA Meek...................................... ....... 92

Nat. Mus. Cat. Invert. Foss., 22869. 

Fig. 2. Hinge of right valve. ' X

3. Dorsal view of a small specimen.

4. Posterior view of a larger example with shell removed from left valve, 

showing the imprint of the ridge that borders the muscular scar.

5. Left side view of the same specimen.

6. Left valve of a large specimen. (See Fig. 1 on PI. xix.)

232
U. 8. GEOLOGICAL SURVEY BULLETIN NO. 106 PL. XX

PINNIDXE AND ARCIDXE.
r

PLATE XXI.

233
t»LATE XXI.

BARBATIA MICRONEMA Meek............................... ........ . ' 89

Fig. 1. Left side view of Meek's type of Trapezium micronema, 

Nat. Mus. Cat. Invert. Foss., 7846.

2. Cast of a small broader left valve retaining the surface markings. 

This is like the types of Barbatia coalvillensis, and is from the same 

locality.

Nat. Mus. Cat. Invert, Foss., 22871.

3. Right valve of a rather broad specimen believed to belong.to this 

species from Denton county, Texas.

4. Interior view showing hinge of a more elongate right valve from the 

 same locality.

. Nat. Mus. Cat. Invert. Foss./ 22870.

NEMODON SULCATINUS E. & S.?:............................................. 91

Fig. 5. Cast of left valve enlarged two diameters.

Nat. Mus. Cat. Invert. Foss., 22872. \

YOLDIA SUBELLIPTICA n. Sp ..........................................____ 94

Figs. 6,7. Opposite views of the type specimen enlarged. 

Nat. Mus. Cat. Invert. Foss., 22873.

SOLEMYA? OBSCURAU. sp................................................__ 95

Fig. 8. Cast of left (?) valve retaining portions of the shell. 

Nat. Mus. Cat. Invert. Foss., 22874.

NUCULA COLORADOENSIS n. Sp.............................................. 94 ;

Fig. 9. View of right valve enlarged.

Nat. Mus. Cat. Invert. Foss., 22876.

CRASSATELLA EXCAVATAEU sp ........................_................_. 96

v Nat. Mus. Cat. Invert. Foss., 22875. 

Fig. 10. Left valve of the best preserved type.

11. Hinge of another left valve.

12. Right valve slightly distorted by pressure.

13. Hinge of same.

234
U. S. GEOLOGICAL SURVEY BULLETIN NO. 106 PL. XXI

ARCID/E, NUCULID/E, SOLEMYID/E AND CRASSATELLID/E.
236
PLATE XXII.

Page. 

UNIO sp.................................................................... 95

Fig. 1. A small right valve.

Nat. Mus. Cat. .Invert. Foss., 22877. 

LUCINA juvBNisn.sp ....................................................... 98

Nat. Mus. Cat. Invert. Foss., 22878. 

Figs. 2,3. Opposite views of one of the types, enlarged.

4. Left valve of another more convex specimen, enlarged.

LUCINA SUBUNDATAH. &M. 1.............................................. 97

Nat. Mus. Cat. Invert. Foss., 22879. 

Fig. 5. Small right valve retaining portions of the natural surface.

6. Left side view of one of the largest casts. 

CARDIUM TRITE White ..................................................... 100

Fig. 7. Cast of right valve (after White).

8. Portion of the surface, magnified (after White). 

CARDIUM .PAUPERCULUM Meek ..................................__........ 99

Fig. 9. Anterior view of both valves, enlarged. 

Nat. Mus. Cat. Invert. Foss., 22880.

10. Left valve from Bear Eiver city, Wyoming, enlarged. The surface 

is slightly eroded, so that the ribs appear unnaturally broad. 

Nat. Mus. Cat. Invert. Fossv 22881.

11. Right Vialve from Huerfano park, Colorado, enlarged. 

Nat. Mus. Cat. Invert. Foss., 22880.

12. Small right valve of broad variety from Coalville, Utah. 

Nat. Mus. Cat. Invert. Foss., 22882.

CYRENA INFLEXA.Meek.............. *..................... ............. 103

Fig. 13. Right valve of one of the types (after White).

CYRENA ^EQUILATKRALIS Meek ?......................................... _. 102

Fig. 15. A left valve doubtfully referred to the species.

Nat. Mus. Ca. Invert. Foss., 22883. 

14. Hinge of same.

236
U. S. GEOLOGICAL SURVEY BULLETIN NO. 108 PL. XXII

11

UNIONID/C, LUCINID/E, CARDIID/E AND CYREN1D/E.
PLATE XXIII.

237
PLATE XXm.

v

Page. 

CTRENA SECURIS Meek...................................................... 101

Fig. 1. Left valve.

Nat. Mtis. Cat. Invert. Foss., 22884.

2. Hinge of same.

3. Right valve of specimen from southern Utah believed to belong to 

this species. 

Nat. Mus. Cat. Invert. Foss., 22885.

CYRENASp................................................................. 102

Fig. 4. Right valve associated with specimen represented by Fig. 3.

Nat. Mus. Cat. Invert. Foss., 22886. 

VENIELLA GONIOPHORA Meek............................................... 105

Fig. 5. Right side view of an internal cast (after Meek). 

VENIELLA MORTONIM.&H............................................__. 104

Nat. Mus, Cat. Invert. Fose., 22887, 

Fig. 6. A small left valve.

7. A email right valve.

8. A large left valve.

9. Hinge of same.

288
U. S. GEOLOGICAL SURVEY BULLETIN NO. 106 PL. XXIII

CYRENIDXE AND CYPRINID/E.
PLATE XXIV.

239
PLATE XXIV.

Pago. 

TAPES CYPRIMERIFOKMIS n.sp......................................_..... 106

Nat. Mus. Cat. Invert. Foss., 22890. 

Fig. 1. Right valve of a large specimen.

2. Dorsal view of same.

3. Left valve of a more convex example.

4. Dorsal view of same.

5. Interior of left valve, from gutta-percha mold of natural cast supplemented by specimens of the shell. *

6. Interior of right valve obtained in same manner as preceding. 

CALLISTA (APHRODINA?) TENTHS H.&M .......................j............ 109

Figs. 7,8. Two views of one of the types (after Meek). 

CALLISTA (Dosnnopsitf?) ORBICULATA H. & M............................... 108

Figs. 9,10. Two views of one of the types (after Meek).

LEGUMEN?Sp............................................................... 107

Fig. 11. Cast of left valve.

Nat. Mus. Cat..Invert. Foss., 22891.

240
U. S. GEOLOGICAL SURVEY BULLETIN NO. 106 PL. XXIV

VENERID/E.
PLATE XXV.

Bull. 106
PLATE XXV.

Paga 

DONAX CUNEATA n. Sp.............................. ....................... 110

Fig. 1. Cast of right valve retaining small portions of the shell.

Nat. Mns. Cat. Invert. Foss., 22888. . DONAX OBLONGA u. sp ..................................................... Ill

Fig. 2. Cast of a large left valve. *

Nat. Mns. Cat. Invert. Foss., 22889. 

TELLINA MODESTA Meek ..................................................... Ill

Fig. 3. Cast of an elongate right valve that retains sonic of the surface 

markings.

Nat. Mus. Cat. Invert. Foss., 22892. 

TELLINA (PAL^OMOEKA) WHITEI n. sp ..... .......... r ....................... 112

Nat. Mus. Cat. Invert. Foss., 22893. 

Fig. 4. Eight valve of the larger type. . \

5. Left valve of same showing pallial sinus whore the shell is hrokeu.

6. Left valve of another specimen.

7. Dorsal view of same. 

TELLINA ISONEMA Meek..................................................... 113

Fig. 8. Copy of Meek's original figure. 

TELLINA ? SUBALATA Meek.................................................. 113

Fig. 9. Copy of Meek's original figure. 

SlLIQUA HUERFANENSIS n. sp................................................ 114

- Nat. Mus. Cat. Invert. Foss., 22894. 

Fig. 10.'Cast of right valve retaining portions of the shell and showing

the pallial sinus.

Fig. 11. Left valve of another specimen. 

PHARELLA ? PEALEI Meek .................................................. 115

Figs. 12,13. Two vie\vs of the type specimen (after White).

243
U. S. GEOLOGICAL SURVEY BULLETIN NO. 106 PL. XXV

DONACID/E, TELLINID/E AND SOLENID/E.
PLATE XXVI.

243
PLATE XXVI.

Page. 

PHOLADOMYA PAPYRACEA M. & H........................................... 116

Fig. 1. Left valve of type specimen (after Meek). 

PHOLADOMYA COLORADOENSIS n. sp........................................... 116

Fig. 2. Left valve of a small specimen with the surface partly restored from 

other examples.

Nat. Mus. Cat. Invert. Foss.,, 22895. 

ANATINA LINEATA n.sp....................................................... 117

Nat. Mus. Cat. Invert. Foss.,, 2281)6. 

Fig. 3. Left valve of a large broken specimen.

4. A small right valve from a gufcta-percha impression of a natural mold. 

LIOPISTHA (PSILOMYA) MEEKI White..................................... ; .. 118

Fig. 5. Left valve retaining portions of the shell and showing faint punctate radiating lines.

Nat. Mus. Cat. Invert. Foss., 22897.

6. Dorsal view of another specimen to show convexity of the valves.

7. Eight valve of one of the type specimens.

Nat. Mus. Cat. Invert. Foss., 8647. 

LIOPISTHA (PSILOMYA) CONCENTRICA n. sp................................... 119

Nat. Mus. Cat. Invert. Foss., 22898.

Fig. 8. Left valve.

9. Dorsal view of same.

10. Eight valve. 

LIOPISTHA (PSILOMYA) ELONGATA n. sp..................................... 119

Nat. Mus. Cat. Invert. Foss., 22899. 

Fig. 11. Left valve. 

12. Eight valve.

244

 4.
U. S. GEOLOGICAL SURVEY BULLETIN NO. 106 PL. XXV]

12

PHOLADOMYID/E AND ANATINID/E.
PLATE XXVII.

245
PLATE XXVII.

Page. 

PARAPHOI-AS SPHENOIDEUS White........................................... 125

Figs. 1, 2. Two views of one of the type specimens (after White).

CORBULA NEMATOPHORA Meek .............................................. 124

Figs. 3, 4. Eight valves of the ordinary size (after White).

COIUJULA KANAIJENSIS n. Sp ................................................. 125

Fig. 5. Left valve.

Nat. Mns. Cat. Invert. Foss., 22900. 

6. Right valve.

CORHULA SUTRIGONALIS M. & H. t........................................... 123

Nat. Mas. Cat. Invert. Foss., 22901. 

Fig. 7. Left valve with portion of the surface restored.

8. Small right valve. v

MACTRA EMMONSI Meek ...................... .............................. 121

Nat. Mas. Cat. Invert. Foss., 22902 and 22903. 

Fig. 9. Small right valve from Hncrfano park, Colorado.

10. 12. Two views of a larger left valve from same place.

11. Cast of left valve from Coalville, Utah.

13. Cast of right valve from Hnerfa.no park, Colorado, showing pallial 

sinus.

MACTK A HUEKFAXENSIS n. sp................................................ 122 <

Nat. Mus. Cat. Invert. Foss., 22904. -v 

Fig. 14. Cast of right valve showing pallial line.

15. Cast of a more elongate right valve retaining portions of the shell. 

MACTRA (CYMIJOPHORA) UTAHENSIS Meek .................................. 120

Fig. 16. Cast of a right valve (after Meek).

17. Cast of another rigTit valve differing in. outline (after Meek).
U. S. GEOLOGICAL SURVEY BULLETIN NO. 106 PL. XXVII

to

MACTRID/E, MYID/E AND PHOLADID/E.
X PLATE XXVIII.

247
PLATE XXVIII.

Page. 

NEIUTINA PISUM Meek...... ................................................. 127

Fig. 1. Dorsal view of Mcek's typo specimen, enlarged.

2. Aperture view of same.

Nat. Mus. Cat. Invert. Foss., 7883.

3. Dorsal view of the type of Nei-itinapisiformis (after White).

NERITINA INCOMPTA White................................................. 128

Figs. 4,5. Opposite views of tbe type specimen (after White).

NEIUTINA ( VELATELLA) PATELLIFOKMIS M'eek............................... 128

Figs. 6,7,8. Three views of one of the type specimens (after White).

9,10. Two views of the type of the variety weberensis (after White). X 

GLAUCONIA COALVILLENSIS Meek ........................................... 132

Fig. 11. Dorsal view of an example from southern Utah. (Sec PI. xix.) 

Nat. Mus. Cat. Invert. Foss., 8249.

TURRITELLA AVHITEI n. Sp............... o................................... 130

Fig. 12. Dorsal view of an average specimen from Upper Kanab, Utah.

Nat. Mns. Cat. Invert. Foss., 22905.

Figs. 13,14,15. Three specimens from Huerfano park, Colorado. Nos. 13 and 

15 have the outer surface of tbe shell somewhat exfoliated. The

revolving ridges on No. 14 are more distinctly nodose than the 

figure indicates.

,-- Nat. Mus. Cat. Invert. Foss., 22906. 

Fig. 16. An example with a peculiar aspect due to exfoliation of the shell.

Nat. Mus. Cat. Invert. Foss.. 22907. 

248
U. S, GEOLOGICAL SURVEY BULLETIN NO. 108 PL. XXVIII

IO

NERITID/e AND TURRITELLID/E.
X PLATE XXIX.

249
PLATE XXIX.

Page. 

GLAUCONIA COALVILLENSIS Meek........... .......... ....................... 132

Fig. 1. An usually large specimen, showing the umbilicus; the type of Cassiope ivhitfieldi (after White).

2. An umbilicated specimen from Coalville, Utah, somewhat distorted 

by pressure. (See PI. xxvm.) 

Nat. Mus. Cat. Invert. Foss., 18446.

TURRITELLA MICRONEMA Meek...... ........ ...I.........................../ 131

Fig. 3. Aperture view enlarged. The outer lip and base of aperture are, 

broken.

Nat. Mus. Cat. Invert. Foss., 22008. 

XENOPHORA STMPSONI n.sp ................................................. 133

Nat. Mus. Cat. Invert. Foss., 22909. 

Fig. 4. Dorsal view of small specimen enlarged two diameters.

5. Aperture view of a cast retaining portions of the shell. Natural size.

6. View of base of the same'specimen, showing the umbilicus. 

G YRODES CONRADI Meek.................................................... 136

Fig. 7. Dorsal view of an example from Huerfano park, Colorado.

Nat. Mus. Cat. Invert. Foss., 22910. 

8. Aperture view of the type (after Meek). 

LUNATIA COKCINNA H. & M. ?............................................... 134

' Nat. Mas. Cat. Invert. Foss., 22911. 

Fig. 9. Aperture view.

10. Dorsal view of another specimen, showing the revolving sculpture. 

GYRODES DEPRESSA Meek................................................... 135

Nat. Mns. Cat. Invert. Foss., 22912. 

Fig. 11. Aperture view of a medium-sized specimen.

12. Dorsal view of a large example.

13. Aperture view of another specimen differing slightly in form.

14. Dorsal view of a specimen in which the spire is unusually prominent and elevated.

*

250
U. S. GEOLOGICAL SURVEY BULLETIN NO. 106 PL. XXIX

TURRITELLID/E, XENOPHORID/E AND NATICID/E.
X PLATE XXX.

251
PLATE XXX.

fago.

Fig. 1. Aperture view restored from the type specimen (after White). 

AMAUROVSIS UTAHENSIS White.............................................. 138

AMAUKOVSIS BULUIFOKMIS Sowerby ......................................... 137

Nat. Mus. Cat. Invert. Foss., 22913.

Fig. 2. Aperture view. A small portion of the shell is broken away at the 

base of the aperture. The spiral punctate lines are not quite so 

prominent on the specimen. 

3,4. Opposite views of a larger specimen. 

SIGAKETUS (E UNATICINA ?) TEXTIIJS, n. sp................................... 139

Nat. Mus. Cat. Invert. Foss.,. 22914.

Fig. 5. Dorsal view of a specimen of average size showing the surface ornamentation. (The outer lip is not thickened, as the drawing would 

indicate. The appearance is caused by accidental defects and by 

the absence of revolving sculpture on that part of the shell.)

6. Aperture view of smaller specimen. The inner lip and umbilicus .

are concealed in the dark shadow. ' 

MESOSTOMA OCCIDENTALS n. sp ............................................ 139

Nat. Mus. Cat. Invert. Foss., 22915.

7. Dorsal view of a nearly perfect specimen, enlarged.

8. Aperture view of a fragment.

EULIMELLA? FUNICULA Meek ..........................-- -- - 14:0

Fig. 9. Aperture view of Meek's type (after White). 

CHEMNITZIA? COALVILLENSIS Meek.......................................... 141

Nat. Mus. Cat. Invert. Foss., 22916.

10. Aperture view of a slender specimen.

11. Aperture view of a stouter specimen. The outer lip and base of the 

aperture are broken in both examples.

252
U. S. GEOLOGICAL SURVEY BULLETIN NO. 108 PL. XXX

NATICID/E, FYRAMIDELLID/E AND RISSOID/E.
PLATE XXXI.

253
PLATE XXXI.

Page. 

APORRHAIS (GONIOCHEILA) CASTORENSIS Whitneld.......................... 143

Fig. 1. Dorsal view of the type (after Whitneld). 

APORKHAIS (PERISSOPTERA ?) PROLABIATA White............................. 144

Fig. 2. Dorsal view of a large specimen with portions of the beak and wing ' 

restored from two specimens. The restoration of the beak is per- * 

haps somewhat too long. .

Nat. Mus. Cat. Invert. Foss., 22917. 

ANCHURA (DKEPANOCHEILUS) RUIDA White................................. 145

Fig. 3,4. Opposite views of the type (after White).

LlSPODESTHES NUPTIALIS White ............................;................ 147

Fig. 5. Dorsal view of small specimen, the type of Lisyovdestlies liiiynlifera,

enlarged (after White).

6. Dorsal view of the type of the species, enlarged (after White). 

PUGNELLUS FUSIFORMIS Meek .............................................. 148

Nat. Mus. Cat. Invert. Foss., 22918.

Fig. 7. Dorsal view of an adult specimen, showing the very heavy calluscovering the spire and with the costne of the body volution shortened into round nodes.

8. Dorsal view of a large specimen of the usual form. The tip of the 

wing-like projection of the outer lip is broken off.

9. Aperture view of a medium sized specimen. The thinner portions 

of the callus covering the spire have been exfoliated.

10. Aperture view of an immature specimen on which the callus has not 

yet developed.

11. Dorsal view of a still younger individual showing the character of

the outer lip at this stage of growth. 

TRITONIUM KANABENSE n. sp................................................ 150

Fig. 12. Dorsal view of the imperfect type specimen. 

Nat. Mus. Cat. Invert. Foss., 22919.

FUSUS SHUMARDI H. & M. ? ................................................ 150

Fig. 13. Dorsal view (after Whitneld). 

Fusus GABBI Meek.............................................;............ 151

Fig. 14. Aperture view of Meek's type (after White). 

TRITONIDEA? HUERFANENSIS n. sp.......................................... 152

15. Dorsal view of the type.

Nat. Mus. Cat. Invert. Foss., 22920.

254
U S. GEOLOGICAL SURVEY BULLETIN NO. 106 PL. XXXI

APORRHAIDXE, STROMBID/E, TRITONID/E AND FUSIDXE.
PLATE XXXII.
PLATE XXXII.

Pago. '.

Fusus (NEPTUNEA?) VENENATUS n. sp...................................... 152

Nat. Mus. Cat. Invert. Foss., 22921. 

Fig. 1. Dorsal view of a small specimen differing slightly from the typo; a

part of the surface restored.

2. Aperture view of the type specimen in which the beak is lacking.. 

FASCIOLAKIA? (CRYPTORHYTIS) UTAHENSIS Meek ........................... 153

Nat. Mus. Cab. Invert. Foss.; 22922.

Fig. 3. Aperture view showing the single fold on the columella. The fold 

is much stronger farther hack in the shell.

4. Dorsal view of another specimen with a small part of the surface Arestored. 

FASCIOLAKIA ? WALCOTTI n. sp.............................................. 153

5. Dorsal view of the type.

Nat. Mus. Cat. Invert. Foss., 22923. 

PYROPSIS COLORADOEXsis n. sp.............................................. 154

Nat. Mus. Cat. Invert. Foss., 22924.

Fig. 6. Dorsal view of fragment showing spire and upper part of hody whorl; 

part of surface restored.

7. Aperture view of another specimen slightly restored iu the lower part, 

of the beak.

8. Dorsal view of the cast showing the full form.

256
U. S. GEOLOGICAL SURVEY BULLETIN NO. 106 PL. XXXII
PLATE XXXIII.

257 

Bull. 106 17
PLATE XXXIII.

Page. 

ADMETOPSIS SUBFUSIFORMIS Meek ........................................... 159

Fig. 1. Aperture view of a specimen from southern Utah referred to Admctopsis gregaria (after Meek.)

2. Similar view of an example from Coalville, Utah (after Meek). 

ADMETOPSIS KHOMBOIDKS Meek............................................. 158

Fig. 3. Aperture view of one of the types (after Meek). 

ADMETOPSIS HUMEROSA n. sp................................................ 100

'Fig. 4."Aperture view.

Nat, Mas. Cat. Invert. Foss., 22925. 

5. Dorsal view of another example.

CANCELLAKIA MALACHITENSIS U. Sp .......................... '. ............... 158

Nat. Mus. Cat. Invert. Foss., 22926. 

Fig. 6. Aperture view of a large specimen.

7. Dorsal view of a smaller specimen, enliirgecl.

ROSTELUTES AMBIGUA U. Sp ..................... .............................. 156

Fig. 8. .Dorsal view of a specimen of average si/.c.

9. Aperture view of same s.howing folds on the colnuiella. 

Nat. Mus .Cat. InVert. Foss., 22927.

10. Aperture view of another specimen that is doubtfully referred to 

this species. 

Nat. Mus. Cat. Invert. Foss., 22929.

ROSTEI,UTES DALLI n. gp .................................................... 156

Fig. 11,12. Two views of the best preserved type. The colnmellar folds are 

not so strong as in R. amliyua and are not visible from the front 

in unbroken specimens. 

Nat. Mus. Cat. Invert. Foss., 22928. 

13. Aperture view of .a stouter individual.

253
U. S. GEOLOGICAL SURVEY BULLETIN NO. 106 PL. XXXIII

/3

CANCELLARIDXE AND VOLUTID/E.
PLATE XXXIV.

259
PLATE XXXIV.

Page. 

ROSTELTJTES GRACILIS n. sp. ................................................ 157

Nat. Mus. Cat. Invert. Foes, 22930. 

Fig. 1. Dorsal view of a small specimen.

2. Aperture view of a fragment showing the strong folds on the columella.

3. Aperture view of a very large specimen believed to belong to this

species. 

PLEUROTOMA? IUTZI Meek.................................................. 161

Fig. 4. Dorsal view of the type (after Meek).

ACTJEON PROPINQUUS n. Sp ................................................. 161

Nat. Mus. Cat. Invert. Foss, 22931. 

Fig. 5,0. Opposite views of the largest type specimen, enlarged.

7,8. Aperture view of another specimen, enlarged and natural size.

HAMINEA TRUNCATA n. sp .................................................. 162

Nat. Mns. Cat. Invert. Foss, 22932.x 

Fig. 9. Dorsal view of a small specimen.

10,11. Opposite view of a large individual.

260
U. S. GEOLOGICAL SURVEY BULLETIN NO. 106 PL. XXXIV

VOLUTID/ , PLEUROTOMID/E, ACT/EONID/E AND BULLID/E.
PLATE XXXV.

261
PLATE XXXV.

Page. 

NAUTILTJS ELEGANS Sowerly ................................................ 163

Fig. 1. Side view of a partly ex/oliated specimen (after Meek). . 

HELICOCEKAS PARIENSE White.............................................. 164

Fig. 2. Septum of the type, magnified. . Nat. Cat. Mus. Invert. FOBS., 8638.

3. A small coiled specimen showing the form of the earlier volutions. 

Nat. Mus. Cat. Invert. Foss., 22933.

4. Copy of White's figure of the type. 

HELICOCEKAS? CORKUGATUM n. sp...................-.. ..................... 165

Fig. 5. Basal view of the type specimen.

Nat. Mus. Cat. Invert. Foss., 22934.

262
U. S. GEOLOGICAL SURVEY BULLETIN NO. 106 PL. XXXV

NAUTILOIDEA AND AMMONOIDEA.
PLATE XXXVI.

263

1.
PLATE XXXVI.

Page. 

BACULITES GRACIUS Slmmard?............................................. 166

Nat. Mus. Cat. Iuvert..Foss., 22935. 

Fig.'1. A long fragment showing the slender, form.

2. Septum of a small specimen, magnified.

3. Fragment of a large example showing constrictions and undulations 

of the surface of the cast.

BACULITES ASPKK Morton 1.................................................. 167

. Fig. 4,5. Two views of a fragment showing tho character of the nodes.

Nat. HUB. Cat. Invert. Foss., 22936. 

ACANTHOCKKAS? KANABKNSE li. Sp.......................................... 181

Nat. Mus. Cat. Invert. Foss., 22937. 

Fig. 6. Side view of specimen, enlarged two diameters.

7. Peripheral view of a large imperfect specimen.

8. Septum of same, enlarged,

 2G4
U. S. GEOLOGICAL SURVEY BULLETIN NO. 106 PL. XXXVI

V

AMMONOIDEA.
PLATE XXXVII.

265
PLATE XXXVH.

Page. 

BUCHICERAS SWALLOVI Shuniard ............................................ 168

Fig. 1. Side view of large specimen (after White).' See PI. xxxvm.

266
U. 8. GEOLOGICAL SURVEY BULLETIN NO. 106 PL. XXXVII

AMMONOIDEA.
PLATE XXXVIII.

267
PLATE XXXVIII.

Page. 

BucinCKUAS swALrovi Shunuird............................................ 168

Nat. Mus'. Cat. Invert. Foss., 22938. 

Fig. 1,2. Two views of a small specimen.

3. Septum of another example, slightly enlarged. (See PI. xxxvn.)

268
U. S. GEOLOGICAL SURVEY BULLETIN NO. 106 PL. XXXVIII

AMMONOIDEA.
PLATE XXXIX.

269
PLATE XXXIX.

Page.

PLACENTICEKAS PLACENTA Delcay ?.......................................... 169

Nat. Mus. Cat. Invert. Foss., 22939.

Fig. 1. Septum of an inner volution of a large specimen, magnified. 

2, 3. Two views of a small nodose specimen,

270 - . .
U. 8. GEOLOGICAL SURVEY BULLETIN NO. 106 PL. XXXIX

AMMONOIDEA.
PLATE XL.

271
PLATE XL.

Page. 

PBIOXOCYCLTJS WYOMINGKNSIS Meek........................................ 171

Fig. 1. Peripheral view of an example from which the keel has been mostly 

broken away (after White).

2. Side view of a small example (after White).

3. Side view of a fragment showing portions of two volutions (after 

White). \

4. Septum of one of the types.

Nat. Mus. Cat. In verb. Foss.. 7729.

272
U. S. GEOLOGICAL SURVEY BULLETIN NO. 106 PL. XL

AMMONOIDEA.
PLATE XLI.

Bull, 106 13 273
PLATE XLI.

Page. 

PRIONOCYCLUS? MACOMBI Meek...............___..... .......... 172

Nat. Mu-i. Cat. Invert. Foss., 22940.

Fig. 1. Side view of a small specimen, enlarged 1£ diameters. The drawing shows too great a convexity.

2. Side view of a larger fragment showing the inner volutions, the serrate keel, and unusually strong nodes near the periphery.

3. Septum of another specimen magnified. 

4,5. Two views of the type (after Meek).

274
U. S. GEOLOGICAL SURVEY BULLETIN NO. 106 PL. XLI

AMMONOIDEA.
 nix
PLATE XLII.

Pago. 

PKIONOTROPIS WOOLGARI Mantell........................................... 174

Fig. 1,2. Two views of a small specimen (after Meek).

3. Peripheral view of a fragment of a large individual (after Meek).

4. Septum of a small specimen, magnified (after Meek). X" 

PRIONOTROPIS HYATTI n. sp ................................................. 176

Nat. Mus. Cat. Invert. Foss., 22941. 

Fig. 5,6. Two views of a specimen of average size.

7. Side view of a smaller-example.

8. Septum of a small specimen, magnified.

276

...I
U. S. GEOLOGICAL SURVEY BULLETIN NO. 106 PL. XLII

AMMONOIDEA.
teJ M

I-H 

I i
PLATE XLIII.

Page. 

MORTONICERAS SHOSHONENSE-Meek............. ...... ............... 179

Fig. 1,2. Two views of the type specimen (after Meek). 

PRIONOTROPIS ? IXEVIANUS White ........................................... 178

Nat. Mus. Cat. Invert. Foss., 8629. 

Fig. 3. Portion of the septum of the type. 

4. Side view of the type (after White).

278
U. S. GEOLOGICAL SURVEY BULLETIN NO. 106 PL. XLIII

AMMONOIDEA.
279
PLATE XLIV.

Page.

MORTONICERAS? VERMILIONENSE M. & "H. .................................. 180

Fig. 1. Side view of the type (after Meek).

SCAPHITES LAKV^EFORMIS M. & H .......................................... 182

Fig. 2. Side view of the type specimen (after Meek).

SCAPHITES VERMIFORMIS M. & H. .....................:.................... 183

Fig. 3. Side view of the type (after Meek). 

SCAPHITES WARRENI M. & H............ .................................... 185

Fig. 4. Side view of the type (after Meek).

5. Side view of a specimen referred to Scapldtcs ivyomingcnsis (after 

Whitfield).

6. Side view of another example (after Whitfield).

7. Septum of a large specimen, enlarged (after Whitfield). 

SCAPHITES VENTRICOSUS M. & H............................................ 186

Fig. 8. Septum, enlarged (after Meek).

9. Side view of the inner volutions (after Meek).

10. Side view of a more perfect specimen from Cinnabar mountain,

Montana. (See PL XJLV).

Nat. Mus. Cat. Invert. Foss, 18817.

2CO
U. S. GEOLOGICAL SURVEY BULLETIN NO. 108 PL. XLIV

AMMONOIDEA.
T

PLATE XLV.

2S1
PLATE XLV.

Page. 

SCAI'HITES VENTRICOSUS M. & H. .......................................... 186

Fig. 1. Peripheral view of large specimen (after Meek). (See PI. XLIV.) 7

SCAPHITES MULLANANUS M. & H............................................ 187

Fig. 2. Septum, enlarged (after Meek).

3,4. Two views of the type (after Meek).

283

X
U. S. GEOLOGICAL SURVEY BULLETIN NO. 106 PL. XLV

AMMONOIDEA.
. INDEX.

[References to descriptions of species are indicated by figures in full-faced type.]

A.

Acantlioceras ? kanabense. ................ 35, 181

Actaeon .................................... 161»

propinquus ............................ 29, 161

subellipticus ........................... 162

Admete ....................................

gregaria. ............................. .1 .58, 100

rhomboides ................... ......... 158

subfusiformis .......................... 159

Admetopsia ................................ 158

humerosa ;..... ...... .................. 100

subfusiforniia.......................... 39,159

Ampullina bulbif'orniis .................... 137 .

Auiauropsis. ............................... 137

alveaba. ................................ 137

bulbiforniis......... ........... -.28, 29. 50, 187

titabensis. ........................... . .39, 1 88

Ammonites ................................ 

bravaisianus ........................... 174

carolinus. .............................. 50, 1 74

germari ................................50, 172

graysonensis . .......................... 48, 170

loeviairuB .............................. 178

jneekiarius .............................48, 170

inullanauua ............................ 187

nodosoidoa ............................ .50, 178

percaxinatus ........................... 174

plao.onta. ............................... 169

serratocarinatua ....................... 171

swallovi...... .......................... 108

veriniliouse ............................ 180

vespertinua ........................... .48, 170

woolgari ............................... 50, 174

Anatina. ................................... 117

lineata... .................... 28, 29, 40, 47, 117

sulcatina. .............................. 117

Anchnra ................................... 145

americana .............................. 14, 146

fuaiformia ............................ .144, 148

newberryi .............................. 148

uuptialia ............................... 147

prolabiata. ............................. 35

(Drepanocbeilus) prolabiata ........... 35, 144

(Drepanocheilus) ruida ................ 35, 145

Ancyloceras aunulatua ..................... 48, .164

Anisomyou ................................ 14,20

Anomia .............

conceutrica. .....

grypboiiiynclius 

micronema ......

nitida ...........

Page. 

................. 66

................. 07

................. 67

...:............. 08

................. 66

obliqua.. .............................. fc 49,68

propatoris ........................ 41 , 4 2, 47, 6 7

subquadrata ......................... 29, 50, 66

tmncata ............................... 50, 67

Aporrhaia. . ................................ 143

occiden tails ................. j... ....... 145

parkinsoiii ............................ 144, 148

reussi .................................. 144

acblotheiini ........................... 144,148

(Perissoptera?) prolabiata.........;.... 144

(Gouiochoila) castorenflia............... 148

Area? coalvillensis ........................ 89

Arkansas valley, Colorado, Cretaceous .section in ............................... 27

list of fossils from.......:.............. 28

Avicnla...............................:.... 72

caudigera .............................. 50,72

gastrodes ......................29.37,48,50, 72

lingiiiformis...................... 1..... 73

(Oxytoma) erecta....................... 72

(Psondoptera) proplenra............... 74

(Pscudoptera) rhy topliora .............. 74

B.

Baculitea................................... 106

anceps .................................22,167

asper.........................25,47,48,51,167

baculoides ............................. 107

boliemicus ............................. 50

gracilis........... -~........32,3D, 35,48, 50,166

incurvatua............................. 51,168

ovatua .................................43,100

Barbatia................................... 89

coalvillcnsia............................ 89

micronema.....................36, 39,44,47, 89

Bear Kiver formation, position of.......... 15,45

section of..............................

Bclemnitella manitobensis..................

Black Hills of Dakota, Cretacooua aection 

in ................... i.................

283

23
284 INDEX.

Page.

British America, Colorado Cretaceous species from............................. 19,49

Bncluceras................................. 103

swallovi............................35,48,168

syriacum............................... 169

C.

Callista.................................... 108

dewey i................................. 108

owenana............................... 108

(Aphrotliiia?) tennis ................... 109

(Dosiniopsis) orbiculata ............... 108

Camptonectes.............................. 72

bellistriata............................. 72

platessa................................ 35, 72

Cancellaria inalachiteusiM..................29,1.58

Canyon city, Colo........................... 27

Cardium................................... 99

curtum ................................ 43

pauperculum ......28, 29, 34, 30, 39,40,45, 48,99

subcurtum............................. 99

trite ................................... 100

Cassidulus stantoni........................ 29, 52

Cassiope whitfteldi......................... 132

Cedar city, Utah, Cretaceous section........ 36

Cenomanian................................ 50, 52

Cephalopoda............................... 163

Cerithium lallicrianum..................... 140

Chemnitzia ? coalvilleusis .................39,141

Coal in the Colorado formation........34,35, 38,45

Coalville. Utah, Cretaceous section......... 37-44

Colorado, Cretaceous sections in............

on Arkansas river... v ................. 27, 28

at Colorado Springs.................... 27

near Denver............................ 26

on Gumnson river...................... 33

in Huerfano park ...................... 29

near Mancos ........................... 32

local lists of Cretaceous fossils from .26,28,29 

Colorado formation.........................

correlated with the Austin limestone

and Eagle Ford shales.................. 48

with the Turanian and Emscher ... 51 

definition of............................ 18

fauna of, compared with other Cretaceous faunas......................... 47

geologic description of................. 20

geographic distribution of............. 19

history of ............................. 13

sections of...........................14, 21-40

Colorado Springs, Colorado ................ 27

Cope, "E. D., correlation of Niobrara limestone, with the Turonian ............ 51

Corbicula,..................................

aequilateralis.......................... 102

crassatelliformis....................... 123

(Vcloritina) durkcei................... 101

Co'rbula.................................... 123

nematopliora..............34, 35,30,39,40,124

kauabensis ............................ 35,125

peraiigulata............................ . 123

perundata ............................. 123

traski.................................. 125

tropidophora........................... 123

subtrigoualis ...........41,42,45,47,123, 125

Page.

Crngin, F. "W., on lower Cretaceous in Kan.. 22 

Crassatclla ................................ 90

cimarronensis.......................... 96

excavata............................... 96

Cretaceous sections inBlack liills............................. 23

Colorado .............................2C-31,33

Iowa................................... 21

Kansas ...........................'..... 22

Minnesota ....'......:.................. 22

Montana............................... 24

Nebraska.............................. 14

New Mexico ............................ 30,31

Utah................................... 34-46

"Wyoming.............................. 35

Criuoidea.................................. 52

Crustacean remains in the Colorado formation .................................... 189

Cucullsea (Trigonarca?) obliq.ua ........... 92

Cyprimeria subalata....................... 113

Cyrena..................................... 301

aequilateralis.......................... 102

carlctoni.........:..................... 41

erecta.................................. 101

inflexa................................. 103

securis ................................ 101

Cy therea...................................

orbiculata.............................. 108

tenuis...'............................... 109

D.

Dakota, Cretaceous in Black hills.......... 23

Dakota formaiion, fossils of................ 21

Dall, W. H., acknowledgments to.......... 12

Dawson, G. M., cited ....................... 49

Denver, Colorado, Cretaceous sections near. 26 

Dione orbiculata........................... 108

tenuis.................................. 119

Donax..................................... 110

cuneata............................43,45,110

1.uta 110

oblonga................................ 40,111

Button, C.B., cited ......................... 34

E.

Eohinodermata ............................. 52

Eldridge, Geo. H., Cretaceous section in

central Colorado ....................... 26

nomenclature and classification of Upper Cretaceous formations............ 18

Emmons, S.F., cited........................ 16,38

Ernscher Mergel........................... 50

Engelmann,Henry, cited................... 37

Eulima? funicula .......................... 140

Eulimella

chry sallis .............................. 41,42

funicula............................36,39,140

inconspicua............................ 41

Euspira coalvillensis ...................... 138

utahensis.............................. 138

Exogyra:

columbella .............................. 48, 63

costata.................................. 63,65
INDEX. 285

Page. 

Exogyra Continued:

firabriata............................... 05

loeviuscula............................. 48, 0-1

ponderosa.............................. Gi, (>5

suborbiculata .....................28, 29, 50, 02

Easciolaria................................. 133

(Cryptorliytis) flexirostata............. 154

(Cryptorliytis) utaliousis...........29,40,153

(Mesorhytis) gracilenta................ 153

walcotti ............... i................ 153

Fauna of the Colorado formation

characteristic species of ............... 48

compared with other Cretaceous faunas 47 

description of species of................ 52

local lists of species of ................. 22-40

Fauna of the Montana formation

characteristic species of................ 48

compared with fauna of the Colorado 

formation............................ 47

Fort Bentoii group.......................14,1C, 24

correlated with the Engle Ford shales.. 19,48 

Fort Pierre group.......................... 14

Fossil plants, list of, from .the Montana

formation at Coalville, Utah........... 42

Fox Hills group............................ 14,18

Fusus...................................... 150

dakotensis ............................. ] 52

gnbbi..................................39,151

shumardi..............................23,150

(Neptunea?) utahrnpis................. 153

(Neptunea?) vcncnatiis ...............29,152

G.

Gastropoda ................................ 127

G ervillia................................... 74

gregaria................................ 74

propleura.........................29, 40,48, 71

Gilbert, G. K., cited ....................... 33,34

Glauconia coalvillonsis.............. 34,39,48,182

Grecnsand................................. 50

Grypluea................................... CO

columba................................ G2

newborryi.....................31, 32, 35,48, 60

pitched.............:............... .31, GO, 02

Gyrodes.................................... ] y 5

conradi................................ 29,130

crenata ................................ 130

dopressa ........................20, 39,40,135

pansus.... 1............................ 130

petrosa ................................ 130

n.

Hague, A., cited............................ 10

Hall and Meok, citod................... ... 13

, Haminea truncata.........................29.102

Haploscapha............................... 85

capax ................................... 85

eccentrica............, .............. 85

grand is ................................ 85

Hayden, F, V,., cited-.....,.,,.,...,,....... 37

Pngn. 

Helicoceras ................................ 104

annulatum ............................. IC-t

corrugatuni............................. 105

mortoni................................ 1 65

pariense............................... 35,104

Hill, R. T.,faunal lists of the Toxan Cretaceous ................................. 48

Hills, E. C., cited on the Laramio of western

Colorado ............................. 31

on the Huerfano park Tertiary bods.... 29

Hippurites................................. 97

Holmes, W. H., cited on Cretaccons of southwestern Colorado .................... 31

Howell, E. E., cited......................... 34

Huerl'ano park, ColoraTlo, Cretaceous section in ............................... 29,30

Tertiary beds .......................... 29

Hyatt, Alpheus, ackiiowleclgmeiils to ...... 12

on tbo genera Trionotropis and Prionocydus..;............................171,170

I.

Idonearca depressa......................... 93

Inoccramus ................................ 70

altus................................... 23

avicnloides..-.................... ..'..... 77

copnlus ................................ 81.

confer! iin-annulatus ................... 77

conradi................................. 80

cuviori............ .................... 50, 51

deformis.................22, 20, 28, 48, 50, 31, 85

dimidins..........................32, 33,48, 78

exogyroides ...................2-1,48,49,81,83

flaccidus ............................... 80

fragilis ............23, 24, 28, 29,3.1, 32, 35, 48, 7fi

gilbert! ................................ 7J>

ho well!................................. 70

involntus ............................48, 51,81

labiatus........ .21, 22, 23, 20,28, 29, 31, 32, 33,35

37, 38, 39, 40,45,48, 49, 50, 5.1, 77 

mytiloidcs ............................. 77

mytilopsis ............................. 77

pcrploxus .............................. 23, 70

problcrnaticns.......................... 77

pseudomytiloides ...................... 77

simpsoni............. ................. 79

tonuirostratus.......................24, S.1, S3

tenuirostris............................ 83

umbonatus .......................24, 48, 51, 81

uudabundus ...................24,48,49,81, 84

Iowa, Cretaceous in........................ 21

Iron city, "Utah, list of fossils from ........ 37

K.

Kanab valley, Utah, Cretaceous section.... 34

Kanarra, Utah, Cretaceous section......... 30

ICansas, Cretaceous section of.............. 22

Lower Cretaceous in ...................

King, Clarence, Colorado formation named

by.:..............--. ..............

Kloos, J.H,, on Cretaceous in Sault valley,

Miiin .................................... . 2J>

Knowlton, F. H., list of fossil plants from

Coalville,Utah,. .,..,.,,,,,,, ,.......... 42
286 INDEX.

L.

Page. 

Lakes,A.,cited ............................ 31

Legumen,sp ..............................29,107

Lesquereux, Leo, cited ...................... 37

Lima............!.......................... 71

utahcnsis .............................. 35, 71

wacoensis.............................. 71

Lingnla subspatulata ...................... 49

Liopistlia.................................. 118

frequens............................... 120

(Psilomya) concentrica ..........28,29,48,119

(Psilomya) elongata ...................35,119

(Psilomya) meeki ..................35,48,118

Lispodesthes.............................. 14G

lingulifera ............................... 147

nuptialis............................... 147

obscurata.............................. 148

Loricula canadensis........................ 49

Lucina ............................... t .... 97

juvenis ................................ 29,98

subundata...........................35, 47, 97

Lunatia.................................... 134

concinna............................35, 47,134

obliquata............................... 134

utaheusis.............................. 135

\

M.

Mactra..................................... 120

emmonsi ........................29', 39,40,121

liuerfanensis...........................29,122

warrenana............................. 122

(Cymbophora?) utahensis ..........39,44,120

Mancos, Colo., Cretaceous section.......... 32

Marcou, Jules, cited ....................... 30

Meek, F. B'., cited .......................13,17,37

Meek and Hayden, Cretaceous section by.. 14 

correlation of American and European

Cretaceous formations ............... 50

Melampus.................................. 162

antiquus............................... 41

Melania.................................... 42

Meretrix orbiculata........................ 108

tennis.................................. 109

Mesostoma occidentalis....................29,139

Minnesota, Cretaceous in................... 20

Modiola.................................... 86

ornata................................. 88

pedernalis.............................. 87

tenuisculpta........................... 49

(Brachydontes) multilinigera. .34,39,41,44,86

Montana, Cretaceous in.................... 24

section of Cretaceous in Cinnabar coal 

field.................................. 24

list of Cretaceous fossils from.......... 24,25

Montana formation......................... 18

characteristic species of........... .... 48

fauna of, compared with Colorado 

fauna ................................ 47

Mortoniceras............................... 179

shoshonense........................48, 51,179

.. .vermiliouense ...... ................... 180

vespertinum........................... 48,51

Mudge, B. F., Cretaceous in Kansas....... 22

Page. 

Natica .....................................

bulbiformis ............................ 137

Concinua............................... 134

moreaueusis ........................... 134

obliquata ........................... 134

rectilabrum............................ 134

Naticina obliqua........................... 139

Nautilus................................... 103

elegans.......................24,48,50, 51,108

texanus................................ 1C3

Nebraska, Cretaceous in ................... 14,21

Nemodon siilcatinus ....................... 35,91

Neritina ..........................:........ 127

bannisteri.............................. 41

bellatula............................... 41

carditoides.............................41,128

incompta............................... 128

pisiformis.............................. 127

pisum.................................39,127

(Velatella) patelliformis............... 39,128

Newberry, Dr. J. S., cited on Cretaceous in

New Mexico.......................... 30,31

New Mexico, Cretaceous in................ 30

Newton, Henry, Cretaceous in the Black

Hills of Dakota ..................:... 23

Niobrara group............................ 15

correlated with Austin limestone....... 19,48

correlated with the Turonian by E. D. 

Cope................................. 51

Nishnabotany sandstone................... 21

Nncula..................................... 94

cancellata.............................. 94

coloradoensis .......................... 94

planimargiuata ........................ 94

0.

Os trea......................................

anomioides ..'...........................

bell i plicata. ............................

blackii.................................

coal villensis............................

congesta................. 22,23,20,31,32,

cortex..................................

i'erdinandi .............................

malnchi tensis ........................28,

malleiformis ...........................

patina. ..j..............................

prudentia ..............................

ratisbonensis ..........................

soleniscns ..................34,36,39,45,

uniformis..............................

P.

54

25,55 

48,58 

58 

41

49,55 

56 

64 

48,58 

29,57 

58 

54'

47,54 

62

47,5« 

69

Pacific coast, Cretaceous formations of..... 49

Parapholas................................125,127

californica ............................. 126

sphenoideus...........................39,125

Peale, A. C., Cretaceous section in western

Colorado, by ......................... 31,33

Pelecypoda ................................ 54

Pharella? .................................. 115

dakotensis............................. 114

p ealei.................................. 115
INDEX. 287

Page. ! 

Pholadomya................................ 116 I

bieweri................................ 117

coloradoenais..........................29, 110

papyracea.....................°..... 24,49, 110

sub ven tricosa.......................39,43,117

ten era-.........-.....--.......--- --- 116

Physa...................................... 103

carletoni............................... 41

Pinna...................................... 88

potrina.................................29,88

stevcnsoni............................. 88

Placenticeras ............".................. 1C9

liardense..............................108,109

placenta?.............-..,..........29,43,109

Placunopsis................................ 68

hilliardensis........................... C8

jurensis................................ 69

Plants, fossil, from Coalvillo, Utah ........ 42

Pleurotoma? hitzi......................... 161

Plicatula................................... 69

arenaria................................ 70

hydrotlieca............................. 09

incongrua.............................. 70

Poromya globulosa......................... 118

Prionocyclns............................... 170

macombi..............................32,172

woolgari ............................... 174

wyomingensis. ..........-23, 28,33,50, 51,171

Prionotropis............................... 174

carolinus............................... 50

hyatti.........................-.28,29,40,170

Itevianus............................... 50

woolgari ............22, 23, 26, 31,48,50,51,174

Pteria.

salinensis.............................. 73

(Oxytoma) erecta...................... 72

(Oxytoma?) gastrodes.................. 72

(Pseutloptcra) proplei i ra ............... 74

(Pseudoptera) rhytopliorsi.............. 74,

Pueblo, Colo............................... 28

Pnguellus.................................. 148

fusiformis.................28,29,40,45,48,148

. rnanubriatus........................... 149

Pugnellns sandstone, distribution of....... 28

list of fossils from...................... 29

Pyropsis................................... 154

bairdi.................................. 155

coloradoensis..........................29,164

K. 

Eadiolites, sp .'............................. 22,90

austinensis ............................ 97

Kapa canoellata............................ 155

Eostellaria rostrata........................ 144

Rostollites............. .................... 155

ainbigua ...............................29,156

dalli.............................28,29, 50,150

elongata............................... 50

gracilis........................ .'... 29,155,157

texana................................. 15s

Eoubideau creek, Colo., Cretaceous section

at mouth of.......................... 32

S. 

ScalariaTuatthewsonii ..................... 142

Scaphites ................,,,,,,,,,.,,,,,,,, 182.

Page.

Scapbites Continued:

asqualis .................... ..-- --- 50,185

hippocrepia............................ 184

bugardianus........................... 183

larvfoformis ...............'............23,182

mullanauus............................24,187

nodosus................................ 180

subglobosus...................... ^..... 187

texanus................................ 185

ventricosus ........................24,25,180

vermiculus............................. 183

veriniformis........................24,49,188

warreni ...................23,33,48,49,50,185

wyoiningensis.......................... 23,185

Schliiter, C., correlation of Austin limestone with the Emscher Mergel. by... 50

Serpula.................................... 53

gordialis............................... 53

intrica................................. 35,68

seinicoalita............................. 49

tenuicarinata.......................... 53

Sigaretus (Eunaticina) tcxtilis ............35,139

Siliq.ua huerfanensis ...................29,39,114

Simpson, Chas. T.,acknowledgments to .... 12

Solemya? obscura.......................... 29,95

Solen guerangeri........................... 115

Stevenson, J. J., cited on Cretaceous iu NewMexico............................... 30

St. John, 0. H., section of Cretaceous in

western Iowa by..................... 21

T.

Tapes cyprimeriforniis .................29,40,100

Tellina.................--....-.........:... Ill

asbburneri............................. ] 12

isoneraa...............................40,118

modesta................................ Ill

jiitidula....-.......................:... 121

subalata..............................40,113

(Palajomrora) inconspicua............. 112

(Pateonicera) wbitei..................29,112

Texas, Upper Cretaceous formations of .... 19,48

Trachy triton vinculum .................... 151

Trapezium micronenia..................... 89

Trigouia sp ................................ 25,96

evansana............................... 95

Trigonarca................................. 92

depressa....'........................... 93

obliqua..............................29,39,92

triquetra............................... 92

i Tritouideahuorfauensis...................29,152

Tritonium kanabense ..................... 35,150

Turbonilla.................................

spillmani .............................. 142

(Chemnitzia?) coalvillensis ............39,141

(Chemnitzia) melanopsis............... 142

1 Turonian fauna compared with fauna of

Colorado formation.................... 50

Turris (Surcula?) nitzi..................... 161

Turritella.................................. 130

coalvillensis ...........................39,132

 martinezensis.......................... 133

micronenia .........................39,40,131

spirouom^.,.,,,,,,,.................... 41
288 INDEX.

Page. 

Turritella Continued:

uvasana ............................... 130

whitei........................28,29,35,48,130

U.

Uintacrinus socialis........................ 22,52

Union sp .................................... 95

Upper Missouri region, Meek and Hayden's

Cretaceous section in ................ 14

Utah, Cretaceous sections in...............

at Cedar city and Kauarra............. 36

Coalvillc............................... 38

Rockport .............................. 44

Upper Kanab.......................... 34

Colorado formation 'in Caatle valley...... 33

local lists of Cretaceous fossils from. .35, 39-44

V.

"Valvata nana .............................. 41

Veniella.................................... 104

goniophora.. .......-.-. ..............35,105

hum ills ................................23,105

mortoni ............................28,47,10*

Vonus faba ................................ 107

Verm es .................................... 53

Vertebrate fauna of the Colorado formation. 51 

Volsella multiliiiigera...................... 86

I Voluta olongata............................ 156

Volutilithes navarrocnsis.................. 155

Volutoderma............................... 155

Volutomorpha ............................. 158

W.

Walcott, C. D., Cretaceous section in Kanab

valley, Utah......................... 34

Weed, ~W. H Cretaceous section in the Cinnabar coal field, Montana............ 24

White, C. A., ci'ted...................'.16,18,31,38

acknowledgments to .................... 11

section of Cretaceous in Iowa.......... 21

Whiteaves, J. F., cited...................... 1.9,49

Winchell, N. H., on Cretaceous in Minnesota. ................................... 20

Woodbury sandstone ...................... 21

Wyoming, Cretaceous in ...........;....... 37, 45

section near mouth of Sulphur creek ... 45

Xcnophora simpsoni...................28.29,183

y.

Yohliasubelliptica.........................29,94