KKILtY iRARY STATE OF ILLINOIS STATE GEOLOGICAL SURVEY FRANK W. DEWOLF, DIRECTOR MONOGRAPH 1 THE MISSISSIPPIAN BRACHIOPODA OF THE MISSISSIPPI VALLEY BASIN PLATES BY STUART WELLER ILLINOIS STATE GEOLOGICAL SURVEY URBANA 1914 EARTH SCIENCES CAMERON, AM BERG SCO. PRINTERS, CHICAGO. Plates and Explanations (All figures are natural size unless otherwise indicated.) The collection in which each specimen used for illustration may be found, has been indicated in the explanation of the plates. The abbreviations used are as follows : W. M. — Collection of Walker Museum, University of Chicago. U. M. — Collection of the University of Michigan. A. M. N. H. — Collection of the American Museum of Natural History, New York. U. S. N. M. — Collection of the United States National Museum, Washington, D. C. I. S. M. — Collection of the Illinois State Museum, Springfield, 111. R. R. R. — Collection of R. R. Rowley, Louisiana, Mo. D. K. G. — Collection of D. K. Greger, Columbia, Mo. F. A. S. — Collection of F. A. Sampson, Columbia, Mo. 727528 EXPLANATION OF PLATE I. Figs. 1-2. LINGULA GORBYI Miller p. 35 Views of two separate valves. (W. M., Nos. 9653 and 9654.) Choutean limestone, Pettis County, Missouri. Fig. 3. LINGULA LOUISIANENSIS n. sp p. 34 View of a single valve, the holotype. (D. K. G., No. 1901.) Louisiana limestone, Louisiana, Missouri. Fig. 4. LINGULA HALLI White p. 35 View of a single valve, the holotype. (U. M., No. 1691.) Burlington limestone, Burlington, lozva. Fig. 5. LINGULA MEMBRANACEA Winchell p. 33 View of a single valve, the holotype. (U. M., No. 1330.) Chonopectus sandstone, Burlington, Iowa. Fig. 6. LINGULA VARSOVIENSIS Worthen p. 36 View of a single valve, the holotype. (I. S. M., No. 2601.) Warsaw beds, IVarsaiv, Illinois. Fig. 7. LINGULA INDIANENSIS Miller & Gurley p. 37 View of a single valve, the holotype. (W. M., No. 6187.) Crawfordsville shale, Crawfordsville, Indiana. Fig. 8. LINGULA sp. View of an imperfect valve. (W. M., No. 7885.) Chester group, Chester, Illinois. Fig. 9. LINGULA sp. View of an imperfect specimen. (W. M., No. 14497.) St. Louis limestone, Monroe County, Illinois. Fig. 10. BARROISELLA SUBSPATULATA (Meek & Worthen). View of a single, very perfect valve. (W. M., No. 7887.) Devonian black shale, Union County, Illinois. Fig. 11. GLOSSINA SEDALIENSIS (Miller) p. 37 View of an incomplete valve with the outline restored. (W. M., No. 9652.) Chouteau limestone, Pettis County, Missouri. Fig. 12. GLOSSINA LINEOLATA (Rowley) , p. 38 View of a single valve, one of the cotypes. (R. R. R.) Louisiana limestone, Louisiana, Missouri. Fig. 13. ORBICULOIDEA CAPAX (White) p. 39 View of the holotype, an imperfect brachial valve. (U. M., No. 1331.) Chonopectus sandstone, Burlington, Iowa. Figs. 14-17. ORBICULOIDEA KEOKUK (Gurley) p. 41 14-15. Views of the cotypes of the species, a pedicle and a brachial valve. (W. M., No. 6331.) 16-17. Views of two pedicle valves, one external and the other internal. (W. M., No. 14787.) Crawfordsville shale, Crawfordsville, Indiana. Fig. 18. ORBICULOIDEA sp. View of a very perfect brachial valve. (W. M., No. 12281.) Productus magnus bed, Ste. Genevieve County, Missouri. 5 Figs. 19-20. ORBICULOIDEA BATESVILLENSIS Weller p. 42 Views of the internal casts of two brachial valves, the cotypes. (W. M., No. 4963.) Batesville sandstone, Batesville, Arkansas. Figs. 21-22. ORBICULOIDEA SAMPSONI (Miller) p. 40 21. View of a brachial valve, the holotype. (W. M., No. 6962.) 22. View of another brachial valve. (W. M., No. 9674.) Chouteau limestone, Sedalia, Missouri. Figs. 23-24. ORBICULOIDEA VARSOVIENSIS (Worthen) p. 41 Views of the cotypes. 24. A nearly complete pedicle valve from the inner side. 23. Two much crushed valves upon a fragment of limestone. (I. S. M., No. 2545.) Keokuk limestone, Warsaw, Illinois. Figs. 25-26. CRANIA REPOSITA White p. 44 25. View of four specimens of pedicle valves attached to a shell of Spirifer grimesi. 26. View of a fourth individual from another portion of the same -S\ grimesi. Cotypes. (U. M., No. 1692.) Burlington limestone, Burlington, Iowa. Figs. 27-29. CRANIA CHESTERENSIS Miller & Gurley p. 45 Views of the cotypes, attached to the bases of the bryozoan Lyrio- pora, and to a shell of Spirifer. (W. M., No. 6067.) Chester beds, Chester, Illinois. Fig. 30. CRANIA MISSOURIENSIS Weller p. 43 Exterior view of a brachial valve, the holotype. (W. M., No. 13902.) Fern Glen formation, Fern Glen, Missouri. Fig. 31. CRANIA SPICULATA Rowley p. 47 View of a brachial valve, the holotype. (R. R. R.) Louisiana limestone, Louisiana, Missouri. Fig. 32. CRANIA DODGEI Rowley p. 44 View of a brachial valve, the holotype. (R. R. R.) Louisiana limestone, Louisiana, Missouri. Fig. 33. CRANIA L,EVIS Keyes p. 47 View of a brachial valve, one of the cotypes. (R. R. R.) Burlington limestone, Louisiana, Missouri. Figs. 34-36. CRANIA BLAIRI Miller p. 46 34-35. External and internal views of a brachial valve. (W. M., No. 9675.) 36. View of a large brachial valve. (W. M., No. 14310.) Chouteau limestone, Pettis County and Providence, Mis- souri. Figs. 37-39. CRANIA ROWLEYI Gurley p. 46 View of a brachial valve, the holotype. (W. M., No. 6316.) 38-39. Views of two other brachial valves. (W. M., Nos. 11895 and 13060.) Louisiana limestone, Louisiana, Missouri. ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No. 1. PLATE I. 34 39 EXPLANATION OF PLATE II. Figs. 1-10. LEPT^ENA ANALOGA (Phillips) , p. 49 1-2. Pedicle and brachial views of a nearly complete specimen. 3-4. External and internal views of another smaller pedicle valve. (W. M., No. 4696.) Fern Glen formation, near Kimmswick, Missouri. 5-6. Internal and external views of a nearly complete brachial valve. (W. M., No. 9719.) Chouteau limestone, Pettis County, Missouri. 7-9. Pedicle, lateral and profile views of a nearly complete but somewhat distorted specimen. (W. M., No. 7055.) Chouteau limestone, Green County, Missouri. 10. View of the internal cast of a pedicle valve. (W. M., 347.) Lower Burlington limestone, near Springfield, Missouri. Figs. 11-16. LEPTVENA CONVEXA n. sp p. 52 11. External view of a brachial valve, and 12, external view of a pedicle valve, in which the geniculate curvature of the shell is wanting. (W. M., No. 13356.) Kinderhook, Bed No. 6, Burlington, Iowa. . 13. Internal cast of a pedicle valve, and 14, the impression of the external surface of a brachial valve. (W. M., No. 6659.) Kinderhook, Bed No. 5, Burlington, Iowa. 15-16. Two views of a pedicle valve in which the geniculation of the shell is absent. (W. M., No. 13357.) Kinderhook oolite, Burlington^, Iowa. ,F,igs. 17-18. STREPTORHYNCHUS ULRICHI Hall & Clarke p. 73 External and internal views of a pedicle: valve, the holotype. (U. S. N. M., No. 44994.) Chester group, 2 miles east of Scottsburg, Kentucky. Figs. 19-22. SCHUCHERTELLA cosxATULA (Hall & Clarke) p. 57 19-20. Brachial and pedicle views of a nearly complete specimen, the holotype. 21-22. External and internal views of an incom- plete pedicle valve, the latter showing the entire absence of a median septum. (W. M., No. 14498.) Chester group, Crittenden County, Kentucky. ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No. 1. PLATE II. 22 16 EXPLANATION OF PLATE III. FigS. 1-9. SCHUCHERTELLA LENS (White) p. 55 1-3. Brachial, pedicle and posterior views of a nearly perfect speci- men. 4. Brachial view of another nearly perfect specimen. (W. M., No. 6693.) 5-6. Exterior and interior views of a very perfect pedicle valve. 7. Interior view of a brachial valve. 8. Interior view of a pedicle valve. (W. M., No. 13051.) Louisiana limestone, Louisiana. Missouri. 9. View of a large brachial valve. (W. M., No. 14258.) Louisiana limestone, Calhoun County, Illinois. Figs. 10-11. SCHUCHERTELLA RUBRA Weller p. 56 Brachial and pedicle views of the holotype. (W. M., No. 13911.) Fern Glen formation, near Kimmswick, Missouri. Figs. 12-13. SCHUCHERTELLA FERNGLENENSIS n. sp p. 54 Pedicle and brachial views of a nearly complete but somewhat dis- torted specimen, the holotype. (W. M., No. 13910.) Fern Glen formation, Fern Glen, Missouri. FigS. 14-16. SCHELLWIENELLA IN.EQUALIS (Hall) p. 61 14. A nearly complete internal cast of a brachial valve. (\V. M., No. 6662.) 15-16. Two nearly complete internal casts of pedicle valves. (W. M., Nos. 14755 and 14754.) Kinderhook, Bed No. 5, Burlington, Iowa. Figs. 17-18. SCHELLWIENELLA CRENULICOSTATA n. sp p. 63 17. View of a very perfect pedicle valve, the holotype. (W. M., No. 14233.) Kinderhook oolite, Bed No. 6, Burlington, Iowa. 18. View of a modified internal cast of a nearly complete pedicle valve probably belonging to this species. (W. M., No. 14499.) Kinderhook, Bed No. 5, Burlington, Iowa. Figs. 19-22. SCHELLWIENELLA PLANUMBONA n. sp p. 65 19-20. Two nearly complete but more or less exfoliated pedicle valves. (W. M., No. 14756.) 21-22. Two incomplete and more or less exfoliated brachial valves. (W. M., Nos. 6671 and 14756.) Cotypes. Kinderhook oolite, Bed No. 6, Burlington, Iowa. 10 ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No. 1. PLATE III. EXPLANATION OF PLATE IV. FigS. 1-2. SCHELLWIENELLA BURLINGTONENSIS n. Sp ..p. 67 1. View of a large, partially exfoliated pedicle valve. 2. View of a smaller, somewhat crushed brachial valve. Cotypes (W M No. 13354.) Burlington limestone, Henderson County, Illinois. Figs. 3-5. STREPTORHYNCHUS TENUICOSTATUM n. sp p. 69 3-4. Pedicle and brachial views of a nearly complete example. 5. View of an exfoliated brachial valve. Cotypes (W M No. 9665.) Chouteau limestone, Chouteau Springs, Missouri. Fig. 6. SCHELLWIENELLA ALTERNATA n. sp p. 66 View of a nearly complete but somewhat exfoliated brachial valve, the holotype. (W. M., No. 13355.) Burlington limestone, Burlington, Iowa. Figs. 7-12. SCHELLWIENELLA INFLATA (White & Whitfield) p. 59 7-9. Pedicle, lateral and brachial views of a sulphur cast of one of the cotypes. (W. M., No. 14218.) Kinderhook, Bed No. 6, Burlington, Iowa. 10. View of an internal cast of a nearly complete brachial valve. (W. M., No. 13355.) 11-12. Brachial and lateral views of a nearly complete internal cast of a brachial valve, one of the cotypes. (U. M., No. 1353.) Kinderhook, Bed No. 7, Burlington, Iowa. \2 ILLINOIS STATE GEOLOGICAL SURVEY. ^BB^K • * / • MONOGRAPH No. 1. PLATE IV. -.«.•" ' /,M EXPLANATION OF PLATE V. Figs. 1-19. STREPTORHYNCHUS RUGINOSUM (Hall & Clarke) p. 71 1-5. Pedicle, brachial, lateral, posterior, and anterior views of the holotype. (W. M., No. 11912.) St. Louis chert, Providence, Indiana. 6-9. Pedicle, brachial, posterior, and lateral views of a nearly com- plete specimen. (W. M., No. 10129.) St. Louis limestone, St. .Louis, Missouri. 10-11. View of an internal cast, and a plaster cast of the natural mould of the exterior of the same specimen. One of the cotypes of S. williamsi Weller. (W. M., No. 4956.) Baicsville sandstone, Batesville, Arkansas. 12. View of a pedicle valve. (W. M., No. 14759.) St. Louis limestone, Alton, Illinois. 13. View of an internal cast of a nearly complete brachial valve. 14. View of an internal cast of a pedicle valve. (W. M., No. 14758.) Salem limestone, Hull's Hollow, near Alton, Illinois. 15. View of the internal cast of a small pedicle valve. 16. View of the internal cast of a brachial valve. (W. M., No. 282.) Residual chert, Springfield, Missouri. 17-18. Pedicle and brachial views of a nearly complete specimen. (W. M., No. 10922.) St. Louis limestone, Alton, Illinois. 19. View of a nearly complete pedicle valve. (W. M., No. 10129.) St. Louis limestone, St. Louis, Missouri. 14 ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No. 1. PLATE V. EXPLANATION OF PLATE VI. Figs. 1-14. ORTHOTETES KASKASKIENSIS McChesney p. 77 1-4. Pedicle, brachial, lateral and posterior views of a nearly com- plete specimen. 5-8. Pedicle, brachial, posterior and lateral views of a smaller example. (W. M., No. 10920.) Pella beds, Pella, Iowa. 13-14. Pedicle and brachial views of a nearly complete example. (VV. M., No. 8647.) Chester group, Meade County, Kentucky. 9-12. Brachial, pedicle, posterior and lateral views of a nearly com- plete specimen. (W. M., No. 8648.) Chester group, Randolph County, Illinois. Fig. 15. ORTHOTETES KASKASKIENSIS McChesney (?) p. 77 View of a nearly complete but exfoliated brachial valve which differs from the more typical representatives of the species in having much stronger costae at regular intervals. (W. M., 14760.) Chester group, Red Bud, Illinois. Figs. 16-21. STREPTORHYNCHUS MINUTUM Cumings p. 70 16-18. Pedicle, brachial and posterior views of a complete example (x4). 19-21. Similar views of another example (x4). (W. M.) Salem limestone, Bloomington, Indiana. 16 ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No. 1. PLATE VI. EXPLANATION OF PLATE VII. Figs. 1-4. ORTHOTETES KEOKUK Hall p. 75 1-3. Pedicle, brachial and lateral views of a nearly complete but exfoliated specimen. (W. M., No. 8652.) Keokuk limestone, Keokuk, Iowa. 4. View of an incomplete internal cast of a pedicle valve showing the median septum as a slit. (W. M., No. 363.) Residual chert, Springfield, Missouri. FigS. 5-8. SCHELLWIENELLA CHOUTEAUENSIS n. Sp p. 64 5-6. Pedicle and brachial views of a nearly complete specimen. 7-8. Brachial view of another less complete specimen. Cotypes. (W. M., No. 9856.) Chouteau limestone, Pettis County, Missouri. FigS. 9-10. SCHUCHERTELLA Sp. Views of two imperfect pedicle valves. (W. M., No. 11353.) Glen Park limestone, Glen Park, Missouri. IS ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No. 1. PLATE VII. EXPLANATION OF PLATE VIII. Figs. 1-7. CHONETES SHUMARDANUS DeKoninck p. 89 1. Pedicle valve of a large individual. 2-3. Pedicle and brachial views of a specimen preserving both valves. 4-5. Pedicle and brachial views of another specimen preserving both valves. 6-7. Exterior and interior views of a pedicle valve. (W. M., No. 13940.) New Providence shale, Button Mould Knob, Kentucky. Figs. 8-16. CHONETES MULTICOSTA Winchell p. 79 8-9. Pedicle and brachial views of a large example preserving both valves. (W. M., No. 4700.) Fern Glen formation, Fern Glen, Missouri. 10-11. Views of two large pedicle valves. (W. M., No. 352.) Burlington limestone, near Springfield, Missouri. 12. View of a pedicle valve, the principal one of Winchell's types. (U. M., No. 1343.) Lo-ii'er Burlington limestone (?), Burlington, Iowa. 13. View of a brachial valve, one of Winchell's types. (U. M., No. 1343.) White chert, probably from the Lozver Burlington limestone, Burlington, lozva. 14-15. External impressions of two brachial valves. 16. An internal cast of a pedicle valve. (U. M., No. 1343.) Kinderhook, bed No. 7, Burlington, Iowa. Fig. 17. CHONETES sp. The internal cast of a pedicle valve included among the types of C. multicosta Winchell. (U. M., No. 1343.) Chonopcctits sandstone, Burlington, Iowa. Figs. 18-19. CHONETES BURLINGTONENSIS Weller p. 93 18. View of a pedicle valve, the holotype. (W. M., No. 6669.) 19. View of a brachial valve. (W. M., No. 13943.) Kinderhook oolite, bed Aro. 6, Burlington, Iowa. Fig. 20. CHONETES MISSOURIENSIS n. sp p. 82 View of a large pedicle valve, the holotype. (W. M., No. 8560.) Pierson limestone, near Springfield, Missouri. Figs. 21-29. CHONETES ORNATUS Shumard p. 86 21-24. Pedicle views of four nearly perfect individuals. 25-28. Brachial views of the same four individuals. 29. View of the interior of a brachial valve. (W. M., No. 6726.) Louisiana limestone, Louisiana, Missouri. Fig. 30. CHONETES GLENPARKENSIS Weller p. 87 View of a pedicle valve, the holotype. (W. M., No. 11355.) Glen Park limestone, Glen Park, Missouri. 21 Figs. 31-34. CHONETES CHESTERENSIS n. sp p. 83 33-34. Pedicle and brachial views of a nearly complete specimen. Cotype. (W. M., No. 7693.) Chester group, Monroe County, Illinois. 31-32. Pedicle and brachial views of a nearly complete specimen. Cotype. (W. M., No. 14761.) Chester group, St. Clair County, Illinois. Figs. 35-42. CHONETES GENICULATUS White p. 92 35-38. Pedicle views of four nearly complete individuals. 39-42. Views of the same four individuals from the brachial side. (W. M., No. 6727.) Louisiana limestone, Louisiana, Missouri. Figs. 43-46. CHONETES LOGANI Norwood & Pratten p. 84 43-44. Views of two pedicle valves. 45-46. Views of two brachial valves. (W. M., No. 13941.) Kinderhook oolite, bed No. 6, Burlington, Iowa. Figs. 47-49. CHONETES GLENPARKENSIS Weller p. 87 Views of three pedicle valves. (W. M., No. 9721.) Chouteau limestone, Pcttis County, Missouri. Figs. 50-55. CHONETES sp. 50-52. External views of three somewhat worn pedicle valves. 53. Exterior view of a brachial valve. 54-55. Internal views of two brachial valves. (W. M.. No. 11354.) Glen Park limestone, Glen Park, Missouri. Figs. 56-57. CHONETES sp. 56. View of the impression of the exterior of a brachial valve. 57. View of a pedicle valve. (W. M., No. 13945.) Kinderhook, bed No. 3, Burlington, Iowa. Figs. 58-62. CHONETES PLANUMBONA Meek & Worthen p. 94 58-59. Pedicle and brachial views of a nearly perfect individual. 60-61. Similar views of a second example. 62. Brachial view of a third specimen. (W. M., No. 7684.) Kcokuk, Ste. Gencvieve County, Missouri. Figs. 63-70. CHONETES ILLINOISENSIS Worthen p. 81 63. Pedicle view of a nearly perfect valve. 64. View of a group of shells, one of which is illustrated separately as fig. 63. (W. M., No. 14380.) Burlington limestone, Boonevillc, Missouri. 65. Pedicle view. 66. Brachial view. 67. View of the interior of a brachial valve. (W. M., No. 2968.) Burlington limestone, Springfield, Missouri. 68. Pedicle view. 69. Brachial view. 70. View of the interior of a brachial valve. (W. M., No. 2969.) Keokuk limestone, near Springfield, Missouri. Figs. 71-72. CHONETES GREGARIUS Weller p. 91 Views of two pedicle valves. (W. M., No. 13944.) Kinderhook, bed No. 3, Burlington, Iowa. Fig. 73. CHONOPECTUS FISCHERI Norwood & Pratten p. 96 View of a very perfect pedicle valve. (W. M., No. 6657.) Kinderhook, bed No. 3, Burlington, Iowa. 22 ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No. 1. PLATE VIII. 8 9 10 12 13 14 15 11 16 25 18 19 20 17 21 22 23 24 3° 31 33 26 27 28 29 32 34 J 35 * 36 37 J 38 r 39 r 40 42 43 44 45 46 47 Jl J J 5O 51 52 53 48 49 54 55 56 57 73 EXPLANATION OF PLATE IX. Figs. 1-10. PRODUCTUS BURLINGTONENSIS Hall p. 104 1-3. Pedicle, posterior and lateral views of a pedicle valve. 4-5. Pedicle and posterior views of another pedicle valve. (W. M., No. 14303.) 6-8. Pedicle lateral and posterior views of a nearly perfect pedicle valve. (W. M., No. 14287.) Burlington limestone, Burlington, Iowa. 9. View of a somewhat imperfect specimen of the interior of a brachial valve. (W. M., No. 345.) Burlington limestone, Springfield, Missouri. 10. View of a nearly complete specimen from the brachial side, showing the concave brachial valve. (W. M., No. 14288.) Burlington limestone, Quincy, Illinois. Figs. 11-17. PRODUCTUS FERNGLENENSIS Weller p. 105 11-13. Pedicle, posterior and lateral views of a nearly complete pedicle valve. 14. View of another pedicle valve. 15. View of a large pedicle valve. 16. View of a brachial valve from the interior, showing the cardinal process ; over the greater portion of the specimen the shell substance has been destroyed so that an impression of the exterior of the valve is exposed. Cotypes. (W. M., No. 4669.) Fern Glen formation, near Kinnnswick, Missouri. 17. View of a pedicle valve. (W. M., No. 8556.) Pier son limestone, near Springfield, Missouri. 24 ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No. 1. PLATE IX. EXPLANATION OF PLATE X. Figs. 1-6. PRODUCTUS INFLATUS McChesney p. Ill 1-3. Pedicle, posterior and lateral views of a nearly perfect pedicle valve. (W. M., No. 14762.) Chester group, Red Bud, Illinois. 4-6. Pedicle, posterior and lateral views of a nearly perfect pedicle valve. (W. M., No. 14304.) Chester group, Meade County, Kentucky. Figs. 7-13. PRODUCTUS MESIALIS Hall p. 1 12 7-9. Pedicle, posterior and lateral views of a pedicle valve. 10-12. Similar views of another example. 13. View of a natural impression of a brachial valve. (W. M., No. 14329.) Chert from Keokuk (?) , Pierce City, Missouri. Figs. 14-24. PRODUCTUS ALTONENSIS Norwood & Pratten p. 124 14. Posterior view of a pedicle valve. (W. M., No. 14295.) Salem limestone, S per gen Hill, Indiana. 15. Brachial view of a nearly complete shell. 16-18. Posterior, brachial and lateral views of a nearly complete shell. (W. M., No. 14305.) Salem limestone, Harrison County, Indiana. 19-21. Pedicle, posterior and lateral views of a nearly complete pedicle valve. (W. M., No. 3142.) Salem limestone, Washington County, Indiana. 22-24. Pedicle, posterior and lateral views of a nearly complete pedicle valve. (W. M., No. 14296.) Salem limestone, Spergen Hill, Indiana. Figs. 25-27. PRODUCTUS TENUICOSTUS Hall p. 119 Pedicle, brachial and lateral views of a nearly complete internal cast of a pedicle valve which probably belongs to this species. (W. M., No. 279.) Residual chert, Springfield, Missouri. ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No. 1. PLATE X. 24 EXPLANATION OF PLATE XI. Figs. 1-5. PRODUCTUS TENUICOSTUS Hall p. 119 1-3. Pedicle, lateral and posterior views of a good pedicle valve. (W. M., No. 14283.) St. Louis limestone, Alton, Illinois. 4-5. Pedicle and lateral views of another pedicle valve. (W. M., No. 14284.) St. Louis limestone, Milan, Illinois. Figs. 6-11. PRODUCTUS VIMINALIS White p. 114 6. Pedicle view of the holotype, a somewhat crushed pedicle valve. 9-10. Pedicle and lateral views of a large pedicle valve, an authentic specimen associated with the holotype in the White Collection at the University of Michigan. (U. M., No. 1693.) Burlington limestone, Burlington, Iowa. 9-10. Pedicle and lateral views of a nearly perfect and undistorted pedicle valve. (W. M., No. 14291.) Burlington limestone, Quincy, Illinois. 11. View of a natural mould of the external surface of the brachial valve, with a portion of the valve, including the cardinal process, adhering posteriorly. (W. M., No. 7925.) Burlington limestone, Springfield, Missouri. Figs. 12-16. PRODUCTUS MESICOSTALIS n. sp p. 114 12. View of a pedicle valve. 13-15. Pedicle, posterior and lateral views of a pedicle valve. 16. Interior view of a bra- chial valve. (W M., No. 10585.) English River grit, Maple Mill, Washington County, Iowa. 28 ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No. 1. PLATE XL EXPLANATION OF PLATE XIII. Figs. 1-12. PRODUCTUS ARCUATUS Hall p. 107 1-3. Pedicle, lateral and posterior views of a very perfect pedicle valve. 4-5. Pedicle and lateral views of a natural mould of the concave brachial valve. (W. M., No. 9823.) Chouteau limestone, Choutcau Springs, Missouri. 6-8. Pedicle, lateral and posterior views of a very perfect pedicle valve. (W. M., No. 14285.) 9-10. Pedicle and lateral views of a nearly complete specimen. 11-12. Pedicle and lateral views of the natural mould of the concave brachial valve of the same shell. (W. M., No. 14330.) Kinderhook oolite, bed No. 6, Burlington, Iowa. Figs. 13-17. PRODUCTUS WORTHENI Hall p. 126 13-15. Pedicle, lateral and posterior views of a nearly perfect pedicle valve. 16. Pedicle view of a natural mould of the external surface of a brachial valve. (W. M., No. 281.) Residual chert, Springfield, Missouri. 17. Pedicle view of a nearly complete natural mould of the ex- ternal surface of a brachial valve. (W. M., No. 294.) Keokuk limestone, near Springfield, Missouri. Figs. 18-23. PRODUCTUS MARGINICINCTUS Prout p. 127 18-19. Pedicle and brachial views of a nearly complete example. 20-21. Pedicle and lateral views of a nearly complete pedicle valve. (W. M., No. 10846.) 22-23. Pedicle and lateral views of another nearly complete pedicle valve. (W. M., No. 14290.) St. Louis limestone, St. Louis., Missouri. Figs. 24-29. PRODUCTUS SCITULUS Meek & Worthen p. 120 24-26. Pedicle, lateral and posterior views of a nearly complete pedicle valve. (W. M., No. 13128.) St. Louis limestone, St. Louis, Missouri. 27-28. Views of two nearly perfect internal casts of pedicle valves. 29. View of the impression of the exterior of a brachial valve. (W. M., No. 14764.) St. Louis limestone (chert), Fountain Creek, Monroe County, Illinois. Figs. 30-35. PRODUCTUS SAMPSON: Weller p. 129 30-33. Pedicle, brachial, lateral and posterior views of a nearly perfect shell. The holotype. (W. M., No. 9695.) Chouteau limestone, Pettis County, Missouri. 34-35. Views of two larger pedicle valves. (W. M., No. 4698.) Fern Glen formation, near Kiinmswick, Missouri. 32 ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No. 1. PLATE XIII. 10 13 14 15 12 11 16 18 19 22 : ^^ 23 24 25 26 30 31 32 20 21 27 28 29 33 34 35 EXPLANATION OF PLATE XIV. Figs. 1-7. PRODUCTUS SEDALIENSIS n. sp p. 108 1-2. Pedicle and lateral views of a large specimen. 3-5. Pedicle, lateral and posterior views of another smaller specimen. 6-7. Pedicle and lateral views of a natural mould of the exterior of a brachial valve. (W. M., No. 9691.) Chouteau limestone, Pettis County, Missouri. Figs. 8-13. PRODUCTUS CURTIROSTRIS Winchell p. 130 8-9. Lateral and pedicle views of a pedicle valve. 10-11. Poste- rior and pedicle views of another pedicle valve. Cotypes. (U. M., No. 1337.) Chonopcctus sandstone, Burlington, Iowa. 12-13. Views of two pedicle valves. In fig. 13 the material has been broken away in such a manner as to exhibit the impres- sion of the brachial valve. (W. M., No. 10576.) English River grit, Maple Mill, Washington County, Iowa. Figs. 14-21. PRODUCTUS BLAIRI Miller p. 110 14-16. Pedicle, brachial and lateral views of a nearly complete specimen. 17-19. Similar views of another example. (W. M., No. 9824.) Chouteau limestone, Chouteau Springs, Missouri. 20-21. Pedicle views of the natural moulds of two brachial valves. (W. M., No. 9692.) Chouteau limestone, Pettis County, Missouri. Figs. 22-23. PRODUCTUS sp. Pedicle and brachial views of a nearly complete shell. (W. M., No. 9825.) Chouteau limestone, Chouteau Springs, Missouri. Figs. 24-25. PRODUCTUS PARVULUS Winchell p. 12S Views of two pedicle valves. Cotypes. (U. M., No. 1338.) Kinderhook, bed No. 5, Burlington, Iowa. Figs. 26-27. PRODUCTUS sp. Pedicle and lateral views of a nearly complete pedicle valve. (D. K. G., No. 2101.) Burlington limestone, Louisiana, Missouri. 34 ILLINOIS STATE GEOLOGICAL SURVEY. 17 MONOGRAPH No. 1. PLATE XIV. i 16 19 22 23 27 26 25 24 EXPLANATION OF PLATE XV. Figs. 1-8. PRODUCTUS MAGNUS Meek & Worthen p. 117 1-3. Pedicle, lateral and posterior views of a nearly complete pedicle valve. 4. View of a natural mould of the exterior of brachial valve. (W. M., No. 14321.) 5. Posterior view of another example showing the arrangement of spine bases along the cardinal margin. (W. M., No. 14765.) Keokuk, Monroe County, Illinois. 6-8. Pedicle, lateral and posterior views of a smaller example, having the characters of the shell described as P. fcutoncnsis by Shumard. (W. M., No. 14308.) Keokuk, Fenton, St. Louis County, Missouri. 36 ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No. 1. PLATE XV. EXPLANATION OF PLATE XVI. Figs. 1-15. PRODUCTUS OVATUS Hall p. 132 1-3. Pedicle, lateral and posterior views of a nearly complete pedicle valve. (Productus pileiformis.) (W. M., No. 14323.) Chester group, Chester, Illinois. 4-5. Pedicle and lateral views of a pedicle valve. 6-7. Direct and profile views of the external impression of a brachial valve. (Productus pileiformis.) (W. M., No. 14314.) Chester group, Meade County, Kentucky. 8-9. Pedicle and lateral views of a nearly complete pedicle valve. (W. M., No. 326.) , Keokuk limestone, near Springfield, Missouri. 10-11. Pedicle and lateral views of a nearly complete pedicle valve. (W. M., No. 10130.) St. Louis limestone, St. Louis, Missouri. 12. Direct view of an incomplete pedicle valve. (Productus Icevi- costus White.) (W. M., No. 6714.) Kinderhook, bed No. 7, Burlington, Iowa. 13. Direct view of a pedicle valve. (Productus l&vicostus White) (W. M., No. 5924.) Chonopcctus limestone, Burlington, Iowa. 14-15. Brachial and pedicle views of an incomplete specimen preserving both valves. (Productus Icuvicostus White) (W. M., No. 296.) Lower Burlington limestone, near Springfield, Missouri. Figs. 16-22. PRODUCTUS PARVUS (Meek and Worthen) p. 121 16-19. Pedicle, brachial, lateral and posterior views of a very perfect shell. (W. M., No. 9915.) Chester group, Chester, Illinois. 20-22. Posterior, lateral and pedicle views of another perfect specimen. (W. M., No. 10923.) Pclla beds, Pella, Iowa. 38 ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No. I. PLATE XVI. "*m 14 15 11 16 17 18 19 20 21 EXPLANATION OF PLATE XVI. Figs. 1-15. PRODUCTUS OVATUS Hall p. 132 1-3. Pedicle, lateral and posterior views of a nearly complete pedicle valve. (Productus pileiformis.) (W. M., No. 14323.) Chester group, Chester, Illinois. 4-5. Pedicle and lateral views of a pedicle valve. 6-7. Direct and profile views of the external impression of a brachial valve. (Productus pileiformis.) (W. M., No. 14314.) Chester group, Meade County, Kentucky. 8-9. Pedicle and lateral views of a nearly complete pedicle valve. (W. M., No. 326.) • Keokuk limestone, near Springfield, Missouri. 10-11. Pedicle and lateral views of a nearly complete pedicle valve. (W. M., No. 10130.) St. Louis limestone, St. Louis, Missouri. 12. Direct view of an incomplete pedicle valve. (Productus Iccvi- costus WhiteJ (W. M., No. 6714.) Kinderhook, bed No. 7, Burlington, Iowa. 13. Direct view of a pedicle valve. (Productus l&vicostus White) (W. M., No. 5924.) Chonopectus limestone, Burlington, Iowa. 14-15. Brachial and pedicle views of an incomplete specimen preserving both valves. (Productus la-z'icostus White) (W. M., No. 296.) Lower Burlington limestone, near Springfield, Missouri. Figs. 16-22. PRODUCTUS PARVUS (Meek and Worthen) p. 121 16-19. Pedicle, brachial, lateral and posterior views of a very perfect shell. (W. M., No. 9915.) Chester group, Chester, Illinois. 20-22. Posterior, lateral and pedicle views of another perfect specimen. (W. M., No. 10923.) Pella beds, Pella, Iowa. ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No. 1. PLATE XVI. 14 , 15 13 22 16 17 18 19 20 21 EXPLANATION OF PLATE XVII. Figs. 1-7. ECHINOCONCHUS ALTERNATUS (Norwood and Pratten) p. 138 1-4. Pedicle, brachial, lateral and posterior views of a nearly com- plete shell without the surface spines. (W. M., No. 14318.) Keokuk limestone, Warsaw, Illinois. 5. View of the interior of a nearly complete brachial valve. (W. M., No. 14316.) Crawfordsville shale, Crawfordsvillc, Indiana. 6-7. Lateral and pedicle views of a pedicle valve from which the spines are missing. (W. M., No. 14319.) Keokuk limestone, Warsaw, Illinois. Figs. 8-9. ECHINOCONCHUS sp. Lateral and pedicle views of a large and nearly complete pedicle valve lacking the spines. (W. M., No. 12988.) St. Louis limestone, Carondelet, Missouri. Figs. 10-15. ECHINOCONCHUS BISERIATUS (Hall) p. 141 10-13. Pedicle, brachial, lateral and posterior views of a nearly perfect specimen, lacking the spines. (W. M., No. 14315.) Salem limestone, Spergen Hill, Indiana. 14. The impression of the external surface of a brachial valve. 15. View of the interior of a brachial valve. (W. M., No. 14766.) Salem limestone, Hull's Hollow, near Alton, Illinois. 40 ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No. 1. PLATE XVII. EXPLANATION OF PLATE XVIII. FigS. 1-6. ECHINOCONCHUS GENEVIEVENSIS II. sp p. 139 1-2. Pedicle and posterior views of a pedicle valve. 3-4. Pedicle and lateral views of another specimen. (W. M., No. 14767.) Ste. Genevieve limestone, 2 mi. N. E. Columbia, Illinois. 5. The impression of the external surface of a brachial valve. 6. View of a small pedicle valve. (W. M., No. 14768.) Ste. Genevieve limestone, Columbia, Illinois. Figs. 7-10. PRODUCTUS INDIANENSIS Hall p. 131 7-8. Views of two brachial valves, natural size. 9-10. Pedicle and lateral views of the specimen illustrated in Fig. 7 (x 4). CW. M., No. 14325.) Salem limestone, Spergen Hill, Indiana. Figs. 11-12. PRODUCTUS sp. External and internal views of a free brachial valve. (W. M., No. 7864.) Salem limestone (f), Jersey County, Illinois. Figs. 13-15. ECHINOCONCHUS MORBILLIANUS (Winchell) p. 142 Pedicle, lateral and posterior views of the holotype. (U. M., No. 2002.) Base of Burlington limestone, Burlington, Iowa. Fig. 16. PRODUCTUS sp. One of the specimens associated with the type of Echinoconchus morbillianus by Winchell, but clearly not a member of the same species. (U. M., No. 2003.) Chonopectus limestone, Burlington, Iowa. Figs. 17-18. STROPHALOSIA KEOKUK Beecher p. 145 A specimen of usual size attached to a shell of Platyceras. 18. The same (x 4). (W. M., No. 13008.) Kcokuk limestone, Crawfordsville, Indiana. Figs. 19-23. STROPHALOSIA SCINTILLA Beecher '.p. 144 19-20. Specimens of usual size attached to the shells of Product- ella pyxidata. (W. M., No. 6701.) 21. Another similar specimen. (W. M., No. 13048.) 22. An enlargement of Fig. 20 to x 4. 23. A similar enlargement of Fig. 21 to x 4. Louisiana limestone, Louisiana, Missouri. 42 ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No. 1. PLATE XVIII. 6 13 14 15 8 11 16 12 20 17 19 21 EXPLANATION OF PLATE XIX. Figs. 1-21. PRODUCTELLA PYXIDATA Hall p. 100 1-14. Pedicle and brachial views of seven nearly perfect shells. 15. View of the interior of a brachial valve. 16-21. Pedicle and lateral views of three very perfect specimens. (W. M., No. 6696.) Louisiana limestone, Louisiana, Missouri. Figs. 22-34. PRODUCTELLA CONCENTRICA (Hall) p. 98 22. View of the natural mould of a brachial valve, the holotype. (A. M. N. H., No. 5080-1.) Kindcrhook, bed No. 5, Burlington, Iowa. 23-24. Views of the natural moulds of two brachial valves, en- tirely similar to the holotype. 25-26. Pedicle and lateral views of a nearly complete pedicle valve. 27-28. Similar views of another example. (W. M., No. 9821.) Choutcau limestone, Choutcau Springs, Missouri. 29-31. Pedicle, brachial and lateral views of a nearly complete specimen. (W. M., No. 6713.) Kinderhook, Burlington, Iowa. 32-34. Pedicle, lateral and posterior views of a nearly perfect pedi- cle valve. (W. M., No. 14769.) Kinderhook, bed No. 6, Burlington, Iowa. Figs. 35-36. STROPHALOSIA CYMBULA Hall & Clark p. 145 Pedicle and brachial views of a nearly complete specimen, the holotype. (W. M., No. 11897.) New Providence shale, south of Louisville, Ky. Figs. 37-38. STROPHALOSIA BEECHERI Rowley p. 146 Pedicle and brachial views of a nearly perfect pedicle valve, filled with matrix, but showing the cardinal area. The holo- type. (R. R. R.) Louisiana limestone, Louisiana, Missouri. Figs. 39-41. PRODUCTELLA NUMMULARIS (Winchell) p. 101 39. View of the exterior of a brachial valve. 40. Internal view of a brachial valve. 41. View of a pedicle valve. Cotypes. (U. M., No. 1340.) Chonopectus sandstone, Burlington, Iowa. 44 ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No. 1. PLATE XIX. 3 8 9 12 23 26 13 14 15 24 27 28 30 31 34 33 v 37 4O 41 39 38 EXPLANATION OF PLATE XX. Figs. 1-8. RHIPIDOMELLA MISSOURIENSIS (Swallow) p. 148 1-3. Pedicle, brachial and lateral views of a very perfect specimen. 4-6. Similar views of another specimen. 7. Internal view of a pedicle valve, showing the muscular scar. 8. Internal view of a brachial valve. (W. M., No. 6692.) Louisiana limestone, Louisiana, Missouri. Figs. 9-18, 30-35. RHIPIDOMELLA DIMINUTIVA Rowley p. 153 9-11. Pedicle, brachial and lateral views of a nearly complete specimen. (R. R. R.) 12-13. Pedicle and brachial views of another example. 14. Internal view of a pedicle valve. 15. Internal view of a brachial valve. (W. M., No. 14222.) Burlington white chert, Louisiana, Missouri. 16-18. Pedicle, brachial and lateral views of a nearly complete specimen. (W. M., No. 8552.) Pier son limestone, near Springfield, Missouri. 30-32. Pedicle, brachial and lateral views of a very perfect speci- men, similar in size to the type specimen. 33-35. Views of the same specimen enlarged (x2). (R. R. R.) Burlington white chert, Louisiana, Missouri. Figs. 19-21. RHIPIDOMELLA sp. Brachial, lateral and pedicle views of a nearly complete but slightly distorted specimen. (W. M., No. 14220.) Fern Glen formation, near Kimmswick, Missouri. Figs. 22-26. RHIPIDOMELLA DUBIA (Hall) *. . .p. 160 22-24. Pedicle, brachial and lateral views of a very perfect ex- ample. 25-26. Internal views of two pedicle valves. (W. M., No. 13055.) Salcin limestone, Spcrgen Hill, Indiana. Figs. 27-29. RHIPIDOMELLA TENUICOSTATA n. sp p. 158 27. Pedicle view of a nearly complete specimen. 28. Brachial view of another specimen. 29. Interior view of a brachial valve. Cotypes. (W. M., No. 9673.) Chouteau limestone, Pettis County, Missouri. Figs. 36-43. RHIPIDOMELLA JERSEYENSIS n. sp .p. 157 36-38. Pedicle, brachial and lateral views of a nearly complete specimen. 39. View of a brachial valve. (W. M., No. 7843.) Fern Glen formation, near Elsah, Illinois. 40. Internal view of a pedicle valve. (W. M., No. 4691.) 41. In- ternal view of another pedicle valve. 42-43. Internal views of two brachial valves. (W. M., No. 4692.) Fern Glen formation, near Kinnnswick, Missouri. 46 ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No. 1. PLATE XX. 27 I * * ^ 30 31 21 33 34 35 42 43 36 37 38 39 40 41 EXPLANATION OF PLATE XXI. Figs. 1-4. RHIPIDOMELLA OWENI Hall & Clarke. p. 151 1-2. External and internal views of a nearly perfect pedicle valve. (W. M., No. 4675.) 3-4. External and internal views of a nearly complete brachial valve. (W. M., No. 7857.) New Providence shale, Button Mould Knob, Kentucky. Figs. 5-7. RHIPIDOMELLA BURLINGTONENSIS (Hall) p. 149 5. View of a nearly perfect pedicle valve. (W. M., No. 11893.) Burlington limestone, Sagctown, Illinois. 6. Similar view of another pedicle valve. (W. M., No. 7858.) Burlington limestone, Burlington, Iowa. 7. Pedicle view of an internal cast, a little restored at the beak. (W. M., No. 13045.) Chert of Burlington limestone, Pike County, Missouri. Figs. 8-27. RHIPIDOMELLA THIEMEI (White) p. 155 9-18. External and internal views of five pedicle valves. 19-24. External and internal views of three brachial valves. 25-27. Pedicle, brachial and lateral views of a nearly complete speci- men. Cotypes. (U. M., No. 1348.) Kinderhook, Bed No. 7, Burlington, Iowa. 8. View of a nearly perfect pedicle valve. (W. M., No. 6670.) Kinderhook, Bed No. 6, Burlington, Iowa. Figs. 28-32. SCHIZOPHORIA SEDALIENSIS n. sp p. 164 28-31. Pedicle, brachial, lateral and posterior views of a nearly perfect specimen. 32. View of the interior of an incomplete pedicle valve, showing the muscular scar. (W. M., No. 14225.) Upper Chouteau limestone, Sedalia, Missouri. Figs. 33-34. SCHIZOPHORIA sp. 33. View of the internal cast of a brachial valve. 34. View of an incomplete internal cast of a pedicle valve. (U. Ml, No. 1351.) Chonopectus sandstone, Burlington, Iowa. 48 ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No. 1. PLATE XXI. f f • • 11 13 15 17 17 19 10 12 14 16 18 20 21 22 23 24 25 26 27 EXPLANATION OF PLATE XXII. Figs. 1-6. SCHIZOPHORIA SWALLOVI (Hall) p. 167 1. View of a very perfect pedicle valve. (W. M., No. 7916.) Burlington limestone, Springfield, Missouri. 2. Similar view of another pedicle valve. 3. View of a small brachial valve. (W. M., No. 7861.) Burlington limestone, Henderson County, Illinois. 4-5. Brachial and posterior views of a nearly complete but some- what crushed example. (W. M., No. 7862.) Burlington limestone, Burlington, Iowa. 6. View of internal cast of a pedicle valve. (W. M., No. 14233.) Chert of Burlington limestone, Sedalia, Missouri. Figs. 7-14. SCHIZOPHORIA POSTSTRIATULA n. sp p. 165 7-11. Pedicle, brachial, anterior, posterior and lateral views of a very perfect, but somewhat unsymmetrical specimen. Cotype. (D. K. G., No. 2701.) Fern Glen formation, Fern Glen, Missouri. 12-13. Pedicle and posterior views of a nearly complete but some- what crushed example. 14. View of the interior of the rostral portion of a pedicle valve. Cotypes. (W. M., No. 4693.) Fern Glen formation, near Kinimswick, Missouri. Figs. 15-17. SCHIZOPHORIA POSTSTRIATULA n. sp. (?) p. 165 Brachial, pedicle and posterior views of a nearly complete but somewhat crushed specimen. (W. M., No. 8553.) Pierson limestone, near Springfield, Missouri. 50 ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No. 1. PLATE XXII. EXPLANATION OF PLATE XXIII. Figs. 1-5. SCHIZOPHORIA SUBELLIPTICA (White & Whitfield) p. 162 1-2. Views of two pedicle valves. (W. M., No. 14227.) 3. View of a brachial valve, one of the cotypes. 5. View of a large brachial valve, one of the cotypes. (U. M., No. 1349.) Kindcrhook, bed No. 6, Burlington, Iowa. Figs. 6-19. SCHIZOPHORIA CHOUTEAUENSIS n. sp p. 163 6-7. Pedicle and brachial views of a nearly perfect specimen. 8-11. Brachial. pedicle, lateral and posterior views of a small but very perfect example. (W. M., No. 14226.) Chontcau limestone, Providence, Missouri. 12-16. Brachial. pedicle, lateral, anterior and posterior views of a nearly perfect specimen. (W. M., No. 9689.) Choutcau limestone, Pettis County, Missouri. 17-19. Brachial, pedicle and posterior views of a nearly perfect shell with much more depressed pedicle valve than usual. It is possible that this specimen should not be referred to this species. (W. M., No. 8572.) Choutcau limestone, Green County, Missouri. Figs. 20-45. CAMAROPHORIA BISINUATA (Rowley) p. 172 20-24. Pedicle, brachial. lateral, anterior and posterior views of a slightly compressed but very perfect internal cast. 25-29. Similar views of another very perfect internal cast. The me- dian septum is shown clearly in both of these specimens, that of the brachial valve less clearly. (W. M., No. 9108.) Residual chert, Springfield, Missouri. 30-33, 34-37, 38-41. Pedicle, brachial, lateral and anterior views of three very perfect specimens, metatypes. Fig. 39 shows clearly the median septum of the brachial valve where the shell has been exfoliated. (R. R. R.) Burlington white chert, Louisiana, Missouri. 42-45. Pedicle, brachial, lateral and anterior views of a very per- fect specimen referred to this species. (W. M., No. 13929.) Kcokuk limestone, Warsaw, Illinois. Figs. 46-51. CAMAROPHORIA EXPLANATA (McChesney) p. 173 46-47. Pedicle and brachial views of a sulphur cast of the holotype. (W. M., No. 12424.) Chester group, Illinois. 48-51. Pedicle, brachial, lateral and anterior views of a very per- fect specimen. (W. M., No. 7726.) Chester group, Chester, Illinois. Figs. 52-60. CAMAROPHORIA HAMBURGENSIS Weller p. 170 52-55. Brachial, pedicle, lateral and anterior views of a small but nearly perfect specimen. 56-58. Views of three detached brachial valves. 59-60. Views of two detached pedicle valves. (W. M., No. 13937.) Hamburg oolite (Kindcrhook), Hamburg, Illinois. 52 ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No. 1. PLATE XXIII. 11 9 10 19 17 18 15 12 13 14 16 28 29 » I 20 21 22 23 24 25 26 27 > • 3O 31 32 33 34 35 * 36 37 42 43 44 45 41 38 39 4O 46 47 48 49 5O 51 52 53 ^^^^ I- 60 59 58 57 55 I 54 EXPLANATION OF PLATE XXIV. Figs. 1-8. CAMAROTCECHIA ELEGANTULA Rowley p. 177 Pedicle, brachial, lateral and anterior views of two nearly perfect specimens. Metatypes. (R. R. R.) Burlington white chert, Louisiana, Missouri. Figs. 9-28. CAMAROTCECHIA TUTA (Miller) p. 179 9-16. Pedicle, brachial, lateral and anterior views of two nearly perfect specimens. (D. K. G., No. 804.) Chouteau limestone, Scdalia, Missouri. 17-20. Pedicle, brachial, lateral and anterior views of a nearly perfect specimen. (D. K. G., No. 1002.) Lake Valley Beds, Sierra County, New Mexico. 21-24. Pedicle, brachial, lateral and anterior views of a nearly complete specimen. (D. K. G., No. 902.) 25-28. Similar views of another, larger specimen probably representing the same species. (R. R. R.) Burlington white chert, Louisiana, Missouri. Figs. 29-33. CAMAROTCECHIA SUBGLOBOSA n. sp p. 180 Pedicle, brachial, lateral, posterior and anterior views of a very perfect internal cast. Holotypes. (D. K. G., No. 702.) Burlington chert, Newark, Knox County, Missouri. Figs. 34-40. CAMAROTCECHIA CHOUTEAUENSIS (Weller) p. 176 34-37. Pedicle, brachial, lateral and anterior views of a very per- fect specimen. Cotypes. (W. M., No. 9704.) Chautcau limestone, Scdalia, Missouri. 38-40. Pedicle, lateral and anterior views of a smaller example. Cotype. (W. M., No. 6709.) Chouteau limestone, Chouteau Springs, Missouri. Figs. 41-60. CAMAROTCECHIA MUTATA (Hall) p. 181 41-48. Pedicle, brachial, anterior and lateral views of two very large individuals. (W. M., No. 7735.) Salem limestone, Spcrgcn Hill, Indiana. 53-60. Pedicle, brachial, lateral and anterior views of three nearly complete specimens. (W. M., No. 13931.) Salem limestone, Hull's Hollow, near Alton, Illinois. Figs. 61-72. CAMAROTCECHIA GROSVENORI (Hall) p. 183 61-62. Pedicle and brachial views of a small specimen. 63. An- terior view of a larger example. 64. The same enlarged (x4). (W. M., No. 13932.) Salem limestone, Stincsville, Indiana. 65-68. Pedicle, brachial, lateral and anterior views of a large specimen. 69-72. Similar views of another specimen. (W. M., No. 13935.) Salem limestone, Bloomington, Indiana. Figs. 73-81. ALLORHYNCHUS HETEROPSIS (Winchell) p. 197 73-76. Brachial, pedicle, lateral and anterior views of a nearly com- plete specimen. 77-79. Pedicle, brachial and lateral views of a very perfect specimen. 80-81. Pedicle and brachial views of a third specimen. (Wl M., No. 4756.) Kinderhook, Bed No. 4, Burlington, Iowa. 55 Fig. 82. RHYNCHOPORA PUSTULOSA (White) p. 230 View of a large pedicle valve. (W. M., No. 4821.) Kinderhook, Bed No. 4, Burlington, Iowa. Figs. 83-86. ALLORHYNCHUS ACUTIPLICATUM n. sp p. 201 Pedicle, brachial, lateral and anterior views of a very perfect speci- men. Holotype. (D. K. G., No. 2404.) Carterville formation1'!). Webb City, Alissonri. 56 ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No. 1. PLATE XXIV. 'U* J ..F V 9 10 11 12 13 6 •\W 14 15 16 J J 17 is 19 20 21 22 23 24 29 30 31 32 33 25 26 27 34 35 36 37 m 38 4O 28 41 42 43 44 45 46 m 47 48 A W^ 49 5O 51 52 53 54 55 56 ' li 57 58 59 6O 61 62 63 64 65 66 o a 67 68 69 7O 71 72 73 74 75 76 I 77 78 83 84 85 86 SO 81 82 EXPLANATION OF PLATE XXV. Figs. 1-6. ALLORHYNCHUS MACRA (Hall) p. 199 1-2, 3-4. Pedicle and brachial views of two examples of about maxi- mum size. (W. M., No. 13936.) Salem limestone, Hull's Hollow, above Alton, Illinois. 5-6. Pedicle and brachial views (x4) of a small example having the characteristics of Rhynchonella ricinula Hall. (W. M., No. 2992.) Salem limestone, Stinesville, Indiana. Figs. 7-17. PUGNOIDES OTTUMWA (White) p. 193 7-9. Pedicle, brachial and posterior views of a large and broad specimen. 10-11, 12-13. Pedicle and brachial views of two very perfect examples. 14-17. Pedicle, brachial, anterior and poste- rior views of a nearly perfect specimen. (W. M., No. 13930.) Ste. Genevieve limestone, Fountain Creek, near Waterloo, Illinois. Figs. 18-21. RHYNCHOPORA (?) PERRYENSIS n. sp p. 239 Pedicle, brachial, anterior and lateral views of a very perfect speci- men. (D. K. G., No. 2304.) Landing 76, Perry County, Missouri. Figs. 22-26. PUGNOIDES BOONENSIS (Shumard) p. 195 Pedicle, brachial, anterior, posterior and lateral views of a very perfect specimen. (D. K. G., No. 2201.) Burlington limestone, Louisiana, Missouri. Figs. 27-33. LIORHYNCHUS GREENIANUM (Ulrich) p. 185 27-30. Pedicle, brachial, anterior and lateral views of a very perfect internal cast. 31-33. Brachial, lateral and anterior views of another specimen. (W. M., No. 13645.) Knobstone shale, New Albany, Indiana. Figs. 34-36. PUGNAX QUADRIROSTRIS Beede p. 204 Pedicle, brachial and lateral views of a very perfect individual (x4). (W. M., No. 2996.) Salem limestone, Bloomington, Indiana. Figs. 37-42. PUGNAX WORTHENI (Hall) p. 203 37-39. Pedicle, brachial and anterior views of a large and nearly perfect specimen. (W. M., No. 13928.) Salem limestone, Hull's Hollow, above Alton, Illinois. 40-42. Similar views of the holotype. (A. M. N. H., No. 5064.) Salem limestone, near Alton, Illinois. Figs. 43-52. SHUMARDELLA MISSOURIENSIS (Shumard) p. 222 43-47. Pedicle, brachial, anterior, posterior and lateral views of a nearly perfect specimen. 48-52. Similar views of another specimen. (W. M., No. 9667.) Chouteau limestone, Chouteau Springs, Missouri. 58 MONOGRAPH No. 1. PLATE XXV. ILLINOIS STATE GEOLOGICAL SURVEY. 12 13 14 5O 51 52 EXPLANATION OF PLATE XXVI. Figs. 1-9. SHUMARDELLA OBSOLENS (Hall) p. 224 1-3. Brachial, anterior and lateral views of a very perfect shell. 4-6. Pedicle, posterior and anterior views of another specimen. 7-9. Brachial and two lateral views of three separate specimens. (W. M., No. 9668.) Chouteau limestone, Chonteau Springs, Missouri. Figs. 10-14. PARYPHORHYNCHUS ELONGATUM Weller p. 191 Pedicle, brachial, lateral, anterior and posterior views of a very per- fect specimen. (D. K. G., No. 3901.) Kinderhook limestone, South Fabius River, southeast cor- ner of Kno.r County, Missouri. Figs. 15-22. PARYPHORHYNCHUS STRIATICOSTATUM (Meek & Worthen) .p. 189 15-19. Pedicle, brachial, lateral, anterior and posterior views of a nearly perfect specimen. (W. M., No. 10784.) Kinderhook limestone, Pike County, Illinois. 20-22. Pedicle, brachial and lateral views of another nearly perfect example. (W. M., No. 6658.) Kinderhook, Bed No. 4, Burlington, Iowa. Figs. 23-28. PARYPHORHYNCHUS TRANSVERSUM Weller p. 188 23. View of a nearly perfect pedicle valve. (W. M., No. 10548.) Kinderhook sandstone, Kinderhook, Illinois. 24-28. Pedicle, brachial, anterior, posterior and lateral views of a nearly perfect internal cast. (U. M., No. 1375.) Chonopectus sandstone, Burlington, Iowa. 60 ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No. 1. PLATE XXVI. 8 28 EXPLANATION OF PLATE XXVII. Figs. 1-6. RHYNCHOTETRA CAPUT-TESTUDINIS (White) p. 206 1-4. Pedicle, brachial, lateral and anterior views of the holotype. (U. M., No. 1376.) Base of Burlington limestone, Burlington, Iowa. 5. View of an incomplete internal cast of a pedicle valve. 6. View of an incomplete internal cast of a brachial valve. (U. M., No. 1376.) Kinder ho ok, Bed No. 7, Burlington, Iowa. Figs. 7-15. RHYNCHOTETRA GIBBOSUM (Greger) p. 211 7-10. Lateral, pedicle, brachial and anterior views of a very perfect, small specimen. Cotype. (D. K. G., No. 3602.) Burlington limestone, Hannibal, Missouri. 11-13. Pedicle, brachial and lateral views of a nearly perfect, large specimen. Cotype. (D. K. G., No. 3702.) Burlington limestone, Louisiana, Missouri. 14-15. Views of two imperfect brachial valves. (VV. M., No. 9715.) Burlington limestone, Marion County, Missouri. Figs. 16-20. RHYNCHOTETRA OVATUM (Greger) p. 208 16-17. Pedicle and brachial views of a nearly perfect shell. 18-20. Pedicle, brachial and lateral views of another specimen. Cotypes. (D. K. G., No. 3802.) Chouteau limestone, Kicsenger Bluff, Warsaw, Benton County, Missouri. 62 ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No. 1. PLATE XXVII. 16 18 19 EXPLANATION OF PLATE XXVIII. Figs. 1-8. RHYNCHOTETRA MISSOURIENSIS n. sp p. 210 1-5. Pedicle, brachial, lateral, posterior and anterior views of a nearly perfect specimen. (W. M., No. 13962.) 6. Anterior view of a specimen. (D. K. G.) 7-8. Posterior and pedicle views of the specimen ground for the cross-sections of the rostral portion of the shell. (W. M., No. 13965.) Burlington limestone, Missouri. Figs. 9-12. RHYNCHOTETRA ELONGATUM n. sp p. 209 Pedicle, brachial, lateral and anterior views of a nearly perfect specimen, the holotype. (W. M., No. 8549.) Pierson limestone, near Springfield, Missouri. Figs. 13-24. TETRACAMERA SUBCUNEATA (Hall) p. 214 13-15. Pedicle, brachial and posterior views of a very perfect speci- men. 16-18. Pedicle, brachial and anterior views of another specimen. 19. Brachial view of a specimen with very broad plications. 20. Pedicle view of a specimen with very concave postero-lateral slopes. 21-22. Brachial and lateral views of a narrow, elongated specimen. 23-24. Pedicle and lateral views of a very short and thick specimen. (W. M., No. 7724.) Salem limestone, Salem, Indiana. Figs. 25-34. TETRACAMERA ARCTIROSTRATA (Swallow) p. 215 25-29. Pedicle, brachial, lateral, anterior and posterior views of a very perfect specimen. (D. K. G., No. 401.) Salem limestone, Boonville, Missouri. 30-34. Similar views of another specimen. (D. K. G., No. 501.) Salem limestone, Alton, Illinois. Figs. 35-39. TETRACAMERA MISSOURIENSIS n. sp p. 216 35-36. Pedicle and lateral views of the internal cast of a pedicle valve. 37-38. Brachial and lateral views of the internal cast of a brachial valve. 39. View of the internal cast of a brachial valve. Cotypes. (W. M., No. 14280.) Residual chert, Callaway County, Missouri. 64 ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No. 1. PLATE XXVIII. .:> 19 20 22 23 24 25 26 27 28 29 30 31 32 33 34 35 37 39 36 38 EXPLANATION OF PLATE XXIX. Figs. 1-13. TETRACAMERA SUBTRIGONA (Meek & Worthen) p. 218 1-5. Pedicle, brachial, lateral, posterior and anterior views of a large specimen. 6-10. Pedicle, lateral, anterior, posterior and brachial views of a smaller specimen. (W. M., No. 8683.) Keokuk limestone, Warsaiv, Illinois. 11. View of an internal cast of a pedicle valve. (W. M., No. 8684.) Chert of Burlington limestone, Louisiana, Missouri. 12. View of an internal cast of a brachial valve. (W. M., No. 320.) Residual chert, Springfield, Missouri. 13. View of an internal cast of a pedicle valve with the matrix broken away to show the spondylium. (W. M., No. 13927.) Residual chert, Aurora, Missouri. Figs. 14-18. RHYNCHOPORA PUSTULOSA (White) p. 230 Pedicle, brachial, lateral, anterior and posterior views of a very per- fect specimen. (W. M., No. 9690.) Kinderhook, Bed No. 4, Burlington, Iowa. Figs. 19-30. RHYNCHOPORA HAMBURGENSIS Weller p. 228 19. View of a pedicle valve. 20-21. Views of two brachial valves. 22. Anterior view of an imperfect specimen. 23-26. Pedicle, brachial, lateral and anterior views of a nearly perfect speci- men. 27-30. Similar views of a smaller specimen. (W. M., No. 7742.) Hamburg oolite, Kinderhook, Hamburg, Illinois. Figs. 31-38. RHYNCHOPORA BEECHERI Greger p. 232 31-32. Pedicle and posterior views of an internal cast. 33-34. An- terior and pedicle views of an internal cast. 35-36. Brachial and pedicle views of an internal cast. 37-38. Brachial and ped- icle views of an internal cast. (W. M., No. 376.) Residual chert, Springfield, Missouri. 66 ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No. 1. PLATE XXIX. 11 12 13 14 15 16 17 18 19 2O 23 24 25 26 27 28 29 30 38 37 36 35 34 33 32 EXPLANATION OF PLATE XXX. Figs. 1-6. RHYNCHOPORA PERSINUATA (Winchell) p. 233 1. View of an internal cast of a pedicle valve. The holotype. (U. M., No. 1998.) 2. Anterior view of a large internal cast, imperfect posteriorly. (W. M., No. 6712.) Kinderhook, Bed No. 7 , Burlington, Iowa. 3-4. Brachial and lateral views of a nearly complete specimen. 5-6. Pedicle and anterior views of another specimen. (D. K. G., No. 1302.) Lake Valley beds, Lake Valley, New Mexico. Figs. 7-15. RHYNCHOPORA? COOPERENSIS (Shumard) p. 235 7-11. Pedicle, brachial, lateral, anterior and posterior views of a nearly complete specimen. (W. M., No. 9661.) Chouteau limestone, Chouteau Springs, Missouri. 12-15. Pedicle, brachial, lateral and anterior views of a nearly com- plete specimen. (R. R. R.) Burlington white chert, Louisiana, Missouri. Figs. 16-17. RHYNCHOPORA sp. 16. View of a pedicle valve. (W. M., No. 6716.) Burlington limestone, Burlington, Iowa. 17. View of a brachial valve probably belonging to the same species. (W. M., No. 13958.) Burlington limestone, Springfield, Missouri. Figs. 18-21. RHYNCHOPORA? ROWLEYI n. sp p. 237 Pedicle, brachial, anterior and lateral views of a very perfect speci- men. (R. R. R.) Louisiana limestone, Louisiana, Missouri. Figs. 22-25. RHYNCHOPORA? COOPERENSIS (Shumard) (?) p. 235 Pedicle, brachial, posterior and lateral views of a somewhat crushed specimen. (W. M., No. 8548.) Pierson limestone, near Springfield, Missouri. Figs. 26-29. CENTRONELLA LOUISIANENSIS n. sp p. 241 26-27. Pedicle and brachial views of a very perfect shell (x4). 28-29. Pedicle and brachial views of another example (x4). (W. M., No. 6730.) Louisiana limestone, Louisiana, Missouri. Figs. 30-33. TRIGERIA ? CURRIEI (Rowley) p. 245 30-31. Pedicle and brachial views of a very perfect shell (x4). 32-33. Pedicle and brachial views of another specimen (x4). (W. M., No. 6732.) Louisiana limestone, Louisiana, Missouri. Figs. 34-39. SELENELLA PEDICULUS (Rowley) p. 244 34-35. Pedicle and brachial views of a very perfect specimen (x4). 36-37. Similar views of another specimen (x4). 38-39. Similar views of a third example (x4). (W. M., No. 6731.) ^Louisiana limestone, Louisiana, Missouri. 69 Figs. 40-42. CENTRONELLA ( > ) EMACIATA Rowley p. 242 Pedicle, lateral and brachial views of a nearly perfect specimen, the holotype. (R. R. R.) Burlington white chert, Louisiana, Missouri. Figs. 43-55. DIELASMELLA COMPRESSA Weller p. 280 43-44, 45-46, 47-48, 49-50. Pedicle and brachial views of four differ- ent specimens. 51. Pedicle view (x4) of specimen figured in Figs. 49-50. 52-53. Pedicle and brachial views (x4) of speci- men figured in Figs. 45-46. 54-55. Pedicle and brachial views (x4) of specimen figured in Figs. 47-48. (W. M., No. 11347.) Glen Park limestone, Glen Park, Missouri. 70 ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No. 1. PLATE XXX. w i IP d 9 10 12 fa 14 15 16 18 19 20 24 23 26 27 28 29 3O ) 11 17 25 I 31 32 33 34 35 36 37 38 39 54 43 44 45 46 47 48 49 5O 40 41 42 51 52 53 55 EXPLANATION OF PLATE XXXI. FigS. 1-4. DlELASMELLA CALHQUNENSIS n. Sp p. 281 1-3, Pedicle, brachial and lateral views of a nearly complete speci- men. 4. View of a partially exfoliated pedicle valve. (W. M., No. 14246.) Hamburg oolite, Kinderhook, Hamburg, Illinois. Figs. 5-15. CENTRONELLOIDEA ROWLEYI (Worthen) p. 247 5-6. Views of a pedicle and a brachial valve, the cotypes. (I. S. M.) 7-10. Pedicle, brachial, lateral and anterior views of a nearly perfect specimen. 11-14. Pedicle, brachial, lateral and posterior views of another specimen. 15. View of the brach- idium. (R. R. R.) Burlington white chert, Louisiana, Missouri. Figs. 16-18. HAMBURGIA TYPA n. sp p. 283 16-17. Views of two pedicle valves. 18. View of a brachial valve. (W. M., No. 14245.) Hamburg oolite, Kinderhook, Hamburg, Illinois. Figs. 19-24. DIELASMOIDES BISINUATA Weller p. 254 19-21. Pedicle, brachial and lateral views of a nearly complete speci- men. 22-24. Similar views of a larger specimen. (D. K. G., No. 1704.) Patrick's Quarry, Middle Fabius River, Lewis County, Mis- souri. Figs. 25-27. DIELASMA SHUMARDANUM (Miller) p. 268 Lateral, pedicle and brachial views of a nearly perfect specimen. (W. M., No. 7770.) Chester group, Big Hill, Jackson County, Illinois. Figs. 28-34. DIELASMA SINUATA n. sp p. 262 28-31. Pedicle, brachial, lateral and posterior views of a nearly com- plete internal cast, somewhat restored anteriorly. 32-33. Views of the internal casts of two brachial valves. (W. M., No. 334.) Residual chert, Springfield, Missouri. 34. View of the internal cast of a brachial valve, the holotype of Lingula crawfordsvillensis Gurley. (W. M., No. 6315.) Crawfordsville shale, Crawfordsville, Indiana. Figs. 35-44. DIELASMA ARKANSANUM n. sp p. 269 35-37. Pedicle, brachial and lateral views of a nearly complete speci- men. 38-40. Similar views of a smaller example. (D. K. G., No. 1505.) Webb City, Missouri (Carterville formation?). 41-43. Pedicle, brachial and lateral views of a nearly complete specimen. 44. Pedicle view of another specimen. Cotypes. (W. M., No. 14255.) Fayetteville, Arkansas. Figs. 45-49. DIELASMA BURLINGTONENSIS (White) p. 261 45-47. Pedicle, brachial and lateral views of a nearly perfect but slightly distorted specimen. 48-49. External and internal views of a pedicle valve, imperfect anteriority. Cotypes. (U. M., No. 1373.) Base of Burlington limestone, Burlington, Iowa. 72 ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No. 1. PLATE XXXI. • I 38 39 4O 45 46 47 48 49 EXPLANATION OF PLATE XXXII. Figs. 1-17. DIELASMA CHOUTEAUENSIS n. sp p. 257 1-4. Pedicle, brachial, lateral and anterior views of a large specimen figured by Hall and Clarke as D. formosa. (W. M., No. 12237.) Chouteau limestone, Missouri. 5. View of a pedicle valve. (W. M., No. 9703.) Chouteau limestone, Pettis County, Missouri. 6-8. Pedicle, brachial and anterior views of a nearly perfect speci- men. 9-12. Posterior, pedicle, brachial and lateral views of a nearly perfect specimen. (W. M., No. 9666.) Chouteau limestone, Chouteau Springs, Missouri. 13-15. Pedicle, brachial and lateral views of an imperfect specimen. 16-17. Brachial and pedicle views of another imperfect speci- men. (W. M., No. 8547.) Pierson limestone, near Springfield, Missouri. Figs. 18-28. DIELASMA INFLATA n. sp p. 264 18-21. Lateral, brachial, pedicle and anterior views of a very perfect specimen, the holotype. (W. M., No. 14235.) Salem limestone, Barrett's Station, Missouri. 22-24. Lateral, brachial and pedicle views of a very perfect but nar- rower specimen. (W. M., No. 7772.) 25-28. Lateral, anterior, pedicle and brachial views of a specimen which probably be- longs to this species. (W. M., No. 7773.) Salem limestone, Spergen Hill, Indiana. 74 ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No. 1. PLATE XXXII. 27 2O 18 EXPLANATION OF PLATE XXXIII. Figs. 1-3. DIELASMA OSCEOLENSIS n. sp p. 260 Pedicle, brachial and lateral views of the holotype. (W. M., No. 7743.) Lower Burlington limestone, Osccola, Missouri. Figs. 4-5. DIELASMA FERNGLENENSIS Weller p. 259 Pedicle and brachial views of the holotype. (W. M., No. 4688.) Fern Glen formation, near Kimmswick, Missouri. Figs. 6-11. DIELASMA SUBSPATULATUM n. sp p. 270 Pedicle, brachial and lateral views of two specimens. Cotypes. (W. M., No. 14254.) Washington County, Arkansas. Figs. 12-17. DIELASMA FORMOSUM Hall p. 265 12-14. Pedicle, brachial and lateral views of the holotype of D. obovata H. & C. (W. M., No. 12238.) Salem limestone (?) , Kentucky. 15-17. Pedicle, brachial and lateral views of a very perfect speci- men of typical form. (W. M., No. 449.) Salem limestone, Spergcn Hill, Indiana. Figs. 18-20. DIELASMA ILLINOISENSIS n. sp p. 267 Pedicle, brachial and lateral views of the holotype. (W. M., No. 14770.) Chester Group, Paint Creek formation, near Modoc, Ran- dolph County, Illinois. 76 ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No. 1. PLATE XXXIII. 6 15 16 17 19 2O EXPLANATION OF PLATE XXXIV. Figs. 1-24. GIRTYELLA iNDiANENSis (Girty) p. 275 1-9. Pedicle, brachial and lateral views of three nearly perfect examples from the typical locality of the species. (W. M., Nos. 7774 and 14237.) Pella Beds, Pella, Iowa. 10-11. Pedicle and brachial views of a nearly perfect specimen. (W. M., No. 14338.) Ste. Genevieve limestone, near Waterloo, Illinois. 12-17. Pedicle, brachial and lateral views of two very perfect speci- mens probably belonging to this species. (D. K. G., No. 1603.) Webb City, Jasper Co., Missouri. (Carterville -formation?) 18-20. Pedicle, brachial and lateral views of a small specimen. 21-24. Pedicle, brachial, lateral and anterior views of another specimen. (W. M., No. 14800.) Lower Chester Group, Rosiclare, Illinois. Figs. 25-36. GIRTYELLA TURGIDA (Hall) p. 273 25-27. Pedicle, brachial and lateral views of a large specimen. 28-31. Pedicle, brachial and lateral views of two smaller speci- mens. (W. M., No. 14234.) Salem limestone, Blooinington, Indiana. 32-C3. Brachial and lateral views of a very convex specimen. 34-36. Pedicle, brachial and lateral views of a small indi- vidual. (W. M., No. 14771.) Salem limestone, Hull's Hollow, Madison Co., Illinois. Figs. 37-41. GIRTYELLA BREVILOBATA ( Swallow) p. 278 37-39. Pedicle, brachial and lateral views of a very perfect speci- men. (W. M., No. 7786.) Chester Group, Golconda, Illinois. 40-41. Pedicle and brachial views of an internal cast. Holotype of Dielasma turgida var. elongata Weller. (W. M., No. 4959.) Batcsville sandstone, Batcsville, Arkansas. Figs. 42-47. GIRTYELLA INTERMEDIA n. sp p. 276 42-44. Pedicle, brachial and lateral views of a very complete speci- men in which the median plication in the brachial valve is well developed. 45-47. Smaller views of another example with the median plication of the brachial valve faintly de- veloped. Cotypes. (W. M., No. 14772.) Paint Creek Formation, near Modoc, Randolph County, Illinois. Figs. 48-50. GIRTYELLA CEDARENSIS n. sp p. 272 Pedicle, brachial and lateral views of an internal cast, the holo- type. The median septum is clearly shown in the brachial view. (D. K. G., No. 1402.) Northview shale, Cedar Gap, Wright County, Missouri. Fig. 51. CRAN/ENA ( ?) ALLEI (Winchell) p. 252 View of the holotype, an internal cast of the pedicle valve. (U. M., No. 2004.) Kinderhook, Bed No. 5, Burlington, Iowa. 79 Figs. 52-54. CRAX.-ENA sp. Pedicle, brachial and lateral views of a nearly complete specimen. (W. M., No. 9716.) Chouteau limestone, Pcttis County, Missouri. Figs. 55-59. CRAN.ENA SULCATA n. sp p. 251 55-57. Pedicle, brachial and lateral views of a very perfect speci- men. 58-59. Brachial and anterior views of another example. Cotypes. (W. M., No. 14250.) Salem limestone, Spcrgen Hill, Indiana. Figs. 60-66. CRAN^NA GLOBOSA n. sp p. 249 Pedicle, brachial and lateral views of a very perfect internal cast. Holotype. (W. M., No. 14249.) Upper Burlington limestone, Springfield, Missouri. 63-65. Pedicle, brachial and lateral views of another specimen. 66. View of the interior of a shell showing the brachidium. (W. M., No. 14248.) Burlington white chert, Louisiana, Missouri. 80 ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No. 1. PLATE XXXIV. 123^ 5 6 7 89 ******** 10 11 12 13 14 15 16 17 J J ) ,) 3 18 19 2O 21 22 23 24 25 26 27 • A 28 29 3O 31 32 33 34 35 36 mjj ^a s 37 38 39 42 43 44 45 46 47 ^I^F ^^ ^^ 41 48 49 5O 51 4O * * i 53 54 55 56 57 58 6O 61 62 63 64 65 66 EXPLANATION OF PLATE XXXV. Figs. 1-5. ATRYPA INFREQUENS n. sp p. 285 1-2. Pedicle and brachial views of the holotype. 3-5. Pedicle, brachial and lateral views of the same specimen enlarged x 2. (W. M., No. 11348.) Glen Park limestone, Glen Park, Missouri. Figs. 6-21. CYRTINA ACUTIROSTRIS (Shumard) p. 286 6-10. Pedicle, brachial, lateral, anterior and posterior views of a perfect specimen. 11-15. Similar views of another specimen. 16-20. Similar views of a third example. 21. View of the interior of a pedicle valve showing the median septum. (W. M., No. 6691.) Louisiana limestone, Louisiana, Missouri. Figs. 22-31. CYRTINA BURLINGTONENSIS Rowley.... p. 288 22-26. Pedicle, brachial, lateral, anterior and posterior views of a perfect specimen. (W. M., No. 9676.) Choutcau limestone, Peltis County, Missouri. 27-30. Pedicle, brachial, lateral and anterior views of the holo- type. (R. R. R.) Burlington white chert, Louisiana, Missouri. 31. View of an internal cast of a pedicle valve showing the median septum as a slit. (R. R. R.) Burlington chert, Louisiana, Missouri. Figs. 32-38. CYRTINA NEOCENES Hall and Clarke p. 289 32-36. Pedicle, brachial, anterior, posterior and lateral views of a nearly complete internal cast. 37-38. Views of two internal casts of pedicle valves. (W. M., No. 5638.) Residual chert, Springfield, Missouri. Figs. 39-40. SPIRIFERINA sp. Pedicle and brachial views of a somewhat crushed specimen. (W. M., No. 7531.) Keokuk limestone, Keokuk, Iowa. Figs. 41-49. SPIRIFERINA TRANSVERSA (McChesney) p. 297 41-44. Pedicle, brachial. anterior and posterior views of a very perfect specimen. 45-48. Similar views of another example. 49. View of the interior of a pedicle valve showing the dental lamellae and median septum. (W. M., No. 7507.) Chester Group, Chester, Illinois. Figs. 50-58. SPIRIFERINA SPINOSA (Norwood and Pratten) p. 299 50-53. Pedicle, brachial, anterior and posterior views of a nearly perfect specimen. (W. M., No. 7496.) Chester Group, Randolph County, Illinois. 54-58. Pedicle, brachial, anterior, posterior and lateral views of another specimen. (W. M., No. 7498.) Chester Group, Monroe County, Illinois. 83 Figs. 59-63. SPIRIFERELLA (?) SCHUCHERTI (Rowley) p. 416 Pedicle, brachial, lateral, posterior and anterior views of a very perfect specimen. Metatype. (R. R. R.) Burlington white chert, Louisiana, Missouri. Figs. 64-72. ACANTHOSPIRA ACICULIFERA (Rowley) p. 413 64-67. Pedicle, brachial, lateral and anterior views of the holotype. 68-71. Pedicle, brachial, lateral, posterior and anterior views of the same specimen enlarged (x 4). (R. R. R.) Louisiana limestone, Louisiana, Missouri. 84 ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No. 1. PLATE XXXV. J 9 11 12 13 14 '6 21 16 22 23 24 25 26 32 27 28 29 30 31 34 10 15 17 18 iQ 20 33 ' "•IS 35 62 63 68 EXPLANATION OF PLATE XXXVI. Figs. 1-5. SPIRIFERINA SALEMENSIS n. sp p. 296 Pedicle, brachial, lateral, posterior and anterior views of the holo- type. (W. M., No. 13948.) Salem limestone, Bloomington, Indiana. Figs 6-7. DELTHYRIS CLARKSVILLENSIS (Winchell) p. 301 6. View of a pedicle valve. 7. Brachial view of a somewhat crushed specimen. (W. M., No. 6699.) Louisiana limestone, Louisiana, Missouri. Fig. 8. DELTHYRIS SUBORBICULARIS Weller p. 303 View of a pedicle valve, the holotype. (W. M., No. 11352.) Glen Park limestone, Glen Park, Missouri. Figs. 9-14. DELTHYRIS MISSOURIENSIS Weller p. 302 9. View of a pedicle valve. 10. View of a brachial valve. (W. M., No. 14276.) Hamburg oolite, Calhoun County, Illinois. 11-12. Views of two pedicle valves. 13-14. Views of two brachial valves. Cotypes. (W. M., No. 11351.) Glen Park limestone, Glen Park. Missouri. Figs. 15-24. DELTHYRIS NOVAMEXICANA (Miller) p. 304 15-16. Views of two imperfect pedicle valves. 17. Posterior view of an incomplete specimen. Cotypes of S. magnicostata Weller. (W. M., No. 4690.) Fern Glen formation, near Kimmswick, Missouri. 18-19. Pedicle and posterior views of an incomplete specimen. 20-21. Pedicle and brachial views of a smaller incomplete specimen. 22-24. Pedicle, anterior and posterior views of a third specimen. (D. K. G.) Lake Valley beds, Lake Valley, New Mexico. Figs. 25-34. SPIRIFERINA SOLIDIROSTRIS White p. 292 25. View of a pedicle valve. 26-27. Views of two brachial valves. 28. Brachial view of a somewhat crushed specimen. Cotypes. (U. M., No. 1372.) Kinderhook, Bed No. 7, Burlington, Iowa. 29. View of the interior of a pedicle valve showing the median septum. 30. View of a pedicle valve. 31-32. Pedicle and posterior views of a pedicle valve. 33-34. Views of two im- perfect brachial valves. (W. M., No. 13949.) Kinderhook, Le Grand, Iowa. Figs. 35-40. SPIRIFERINA SUBTEXTA White p. 291 35-39. Pedicle, brachial, anterior, posterior and lateral views of the holotype. (U. M., No. 1701.) Burlington limestone, Burlington, Iowa. 40. View of a pedicle valve. (W. M., No. 13914.) Fern Glen formation, near Kimmswick, Missouri. 87 Figs. 41-48. SPIRIFERINA NORWOODANA (Hall) p. 295 41-44. Posterior, lateral, brachial and pedicle views of a nearly perfect specimen (x 4). 45-48. Pedicle, brachial, lateral and anterior views of a nearly perfect specimen. (x 4.) (W. M., No. 5636.) Salem limestone, Blooiiiington, Indiana. Figs. 49-53. DELTHYRIS SIMILIS n. sp p. 305 Pedicle, brachial, anterior, lateral and posterior views of a nearly perfect internal cast, the holotype. ( D. K. G., No. 2903.) Residual chert, South Branch, Callaway Co., Missouri. Figs. 54-57. SPIRIFERINA SUBELLIPTICA (McChesney) p. 294 54-55. Pedicle and brachial views of a sulphur cast of the holo- type. (W. M., No. 13239.) Button Mould Knob, Kentucky. 56. View of a pedicle valve. 57. View of the interior of a ped- icle valve showing the median septum. (W. M., No. 13427.) Lebanon, Kentucky. ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No. 1. PLATE XXXVI. 6 15 18 25 3O 35 10 16 17 19 20 21 22 26 27 28 29 31 32 33 34 36 37 38 •M 39 45 46 48 44 > fl 49 5O 51 52 11 13 12 23 24 40 41 42 43 i 53 EXPLANATION OF PLATE XXXVII. Figs. 1-7. SPIRIFER MARIONENSIS Shumard p. 30.S 1-5. Pedicle, brachial, anterior, posterior and lateral views of a nearly perfect specimen. (W. M., No. 6700.) Louisiana limestone, Clarksvillc, Missouri. 6. View of a pedicle valve with much extended hinge-line. (W. M., No. 13335.) 7. Brachial view of a specimen with very short hinge-line. (W. M., No. 6694.) Louisiana limestone, Louisiana, Missouri. Figs. 8-17. SPIRIFER VERNONENSIS Swallow p. 310 8-12. Posterior, pedicle, brachial, anterior and lateral views of a very perfect specimen. 13. View of a large pedicle valve. (W. M., No. 4686.) Fern Glen formation, near Kiminswick, Missouri, 14-17. Pedicle, brachial, anterior and posterior views of a nearly perfect specimen. (W. M., No. 13535.) Fern Glen formation, Fern Glen, Missouri. Figs. 18-21. SPIRIFER OSAGENSIS Swallow p. 314 18-19. Views of two imperfect pedicle valves. 20. View of a brachial valve. (W. M., No. 13545.) Hannibal sandstone, Louisiana, Missouri. 21. View of a brachial valve. (W. M., No. 5957.) Northvicw sandstone, Northview, Missouri. 90 ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No. 1. PLATE XXXVII. 13 EXPLANATION OF PLATE XXXVIII. Figs. 1-5. SPIRIFER PIKENSIS Rowley p. 312 Pedicle, brachial, anterior, posterior and lateral views of the holo- type. (R. R. R.) Burlington limestone, Louisiana, Missouri. Figs. 6-8. SPIRIFER SHEPARDI n. sp p. 313 6-7. Views of two pedicle valves. 8. View of a brachial valve. Cotypes. (W. M., No. 8540.) Pierson limestone, near Springfield, Missouri. Figs. 9-13. SPIRIFER LATIOR Swallow p. 316 Lateral, pedicle, brachial, anterior and posterior views of a nearly perfect specimen. (W. M., No. 6707.) Chouteau limestone, Chouteau Springs, Missouri. 92 ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No. 1. PLATE XXXVIII. 12 13 EXPLANATION OF PLATE XXXIX. Figs. 1-10. SPIRIFER PLATYNOTUS n. sp p. 317 1. View of a pedicle valve. 2. View of a brachial valve. (W. M., No. 6674.) 3-5. Views of three pedicle valves. 6. View of a brachial valve. Cotypes. (W. M., No. 13544.) Kinderhook, Bed No. 6, Burlington, Iowa. 7-10. Pedicle, brachial, anterior and lateral views of a nearly per- fect specimen probably belonging to this species. (W. M., No. 7502.) Kinderhook, Bed No, 5, Burlington, Iowa. Figs. 11-23. SPIRIFER MISSOURIENSIS Swallow p. 319 11-14. Posterior, lateral, pedicle and brachial views of a nearly per- fect example showing the distinct fasciculation of the plications. (W. M., No. 10719.) Chouteau limestone, Pettis County, Missouri. 15-18. Pedicle, brachial, anterior and posterior views of a nearly perfect specimen. 19-23. Posterior, lateral, pedicle, brachial and anterior views of a large specimen somewhat restored at the cardinal extremities. (W. M., No. 9663.) Chouteau limestone, Chouteau Springs, Missouri. Figs. 24-26. SPIRIFER BIPLICATUS Hall p. 320 24-25. Views of two internal casts of pedicle valves. 26. View of the internal cast of a brachial valve. (W. M., No. 5931.) Chonopectus sandstone, Burlington, lozva. Figs. 27-30. SPIRIFER BIPLICOIDES n. sp p. 323 27. View of a plaster cast of the pedicle valve from a natural mould. 28. View of the internal cast of a brachial valve. (W. M., No. 6660.) 29. View of a plaster cast from a natural mould of the pedicle valve. (W. M., No. 14785.) 30. View of the internal cast of a brachial valve. (W. M., No. 14755.) Kinderhook, Bed No. 5, Burlington, Iowa. 94 ILLINOIS STATE GEOLOGICAL SURVEY. A^ONOGRAPH No. 1. PLATE XXXIX. 11 I I • 23 EXPLANATION OF PLATE XL. Figs. 1-23. SPIRIFER LOUISTANENSIS Rowley p. 322 1-5. Pedicle, brachial, lateral, anterior and posterior views of a nearly complete specimen. 6-10. Similar views of another specimen. 11-13. Brachial, lateral and posterior views of another specimen. (W. M., No. 5632.) Chouteau limestone, Green County, Missouri. 14-15. Views of two pedicle valves. (W. M., No. 14153.) Head of Middle River, Callaway County, Missouri. 16-19. Pedicle, brachial, lateral and anterior views of a nearly per- fect specimen. 20-23. Pedicle, brachial, lateral and posterior views of a nearly perfect specimen. Metatypes. (R. R. R.) Burlington white chert, Louisiana, Missouri. Figs. 24-29. SPIRIFER LEGRANDENSIS n. sp p. 326 24-28. Pedicle, brachial, anterior, lateral and posterior views of a very perfect specimen. 29. View of a pedicle valve. Cotypes. (W. M., No. 10720.) Kinderhook, LeGrand, Iowa. Figs. 30-34. SPIRIFER INSCULPTUS Rowley p. 324 Pedicle, anterior, posterior, lateral and brachial views of a nearly perfect specimen. (W. M., No. 13551.) Base of Burlington limestone, Fern Glen, Missouri. 96 ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No. 1. PLATE XL. 8 10 11 16 20 12 13 21 > - : 17 18 19 f 22 23 14 15 25 28 27 30 29 33 34 EXPLANATION OF PLATE XLI. Figs. 1-5. SPIRIFER INSCULPTUS Rowley p. 324 Pedicle, brachial, posterior, anterior and lateral views of the holo- type. (R. R. R.) Lower Burlington limestone, Louisiana, Missouri. Figs. 6-14. SPIRIFER INCERTUS Hall p. 335 6. View of a nearly perfect pedicle valve. (W. M., No. 13529.) 7-11. Lateral, pedicle, brachial, posterior and anterior views of a nearly perfect specimen. (W. M., No. 8620.) 12-14. Bra- chial, posterior and pedicle views of the holotype. (A. M. N. H., No. 5111—1.) Burlington limestone, Burlington, Iowa. 98 ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No. 1. PLATE XLI. r t 3 12 EXPLANATION OF PLATE XLII. Figs. 1-3. SPIRIFER FORBESI Norwood and Pratten p. 331 Pedicle, brachial and posterior views of a nearly perfect specimen probably belonging to this species. (R. R. R.) Burlington white chert, Louisiana, Missouri. Figs. 4-16. SPIRIFER TENUICOSTATUS Hall p. 328 4. View of a pedicle valve. 5-9. Pedicle, brachial, anterior, poste- rior and lateral views of a nearly perfect specimen. Cotypes. (A. M. N. H., No. 5121—1 & 2.) Warsaw formation, Dallas and Warsaw, Illinois. 10-13. Pedicle, brachial, posterior and anterior views of a some- what distorted specimen. (W. M., No. 7506.) Keokuk limestone, Bentonsport, Iowa. 14-16. Lateral, pedicle and brachial views of a somewhat crushed specimen. (W. M., No. 7505.) Warsaiv formation, Warsaw, Illinois. Figs. 17-21. SPIRIFER JEFFERSONENSIS Weller p. 369 17-18. Pedicle and posterior views of an incomplete pedicle valve. 19-21. Views of three brachial valves. Cotypes. (W. M., No. 11350.) Glen Park limestone, Glen Park, Missouri. 100 ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No.- 1. PLATE jX 4 m 16 EXPLANATION OF PLATE XLIII. Figs. 1-10. SPIRIFER SUB^EQUALIS Hall p. 327 1-5. Pedicle, brachial, posterior, anterior and lateral views of a nearly perfect specimen. (D. K. G., No. 3501.) Webb City, Jasper Co., Missouri. 6-10. Pedicle, brachial, lateral, posterior and anterior views of a sulphur cast of the holotype. (W. M., No. 14773.) Warsaw limestone, Warsaw, Illinois. Figs. 11-15. SPIRIFER LATERALIS Hall p. 330 Pedicle, brachial, posterior, anterior and lateral views of the holo- type. (W. M., No. 8619.) Clifton, Madison County, Illinois. Fig. 16. SPIRIFER FORBESI Norwood and Pratten p. 331 View of a pedicle valve. (W. M., No. 13549.) Burlington limestone, Pettis County, Missouri. Fig. 17. SPIRIFER IMBREX Hall p. 334 View of a brachial valve, the holotype. (A. M. N. H., 5110 — 1.) Burlington limestone, Burlington, Iowa. 102 ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No. 1. PLATE XLIII. EXPLANATION OF PLATE XLIV. Figs. 1-14. SPIRIFER WASHINGTONENSIS n. sp p. 339 1-4. Pedicle, brachial, lateral and posterior views of a nearly com- plete specimen. 5-7. Posterior, pedicle and anterior views of another specimen. 8-9. Brachial and lateral views of a third specimen. Cotypes. (W. M., No. 13550.) Keokuk limestone, Monroe County, Illinois. 10-12. Anterior, pedicle and brachial views of a nearly complete specimen. Cotypes. (W. M., No. 7522.) Keokuk limestone, Spergen Hill, Indiana. 13-14. Pedicle and brachial views of a nearly complete specimen. Cotypes. (W. M., No. 13577.) Keokuk limestone, Salem, Indiana. Figs. 15-19. SPIRIFER MUNDULUS Rowley p. 333 15-18. Pedicle, brachial, posterior and anterior views of a very per- fect shell. Metatype. (R. R. R.) Burlington white chert, Louisiana, Missouri. 19. View of an incomplete pedicle valve. (W. M., No. 5635.) Burlington limestone, near Springfield, Missouri. Figs. 20-24. SPIRIFER BRECKENRIDGENSIS n. sp p. 342 20-22. Brachial, lateral and anterior views of a very perfect speci- men. 23-24. Pedicle and posterior views of another specimen. (D. K. G., No. 3302.) Chester Group, Breckenridge County, Kentucky. 104 ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No. 1. PLATE XLIV. ? iS^Bi^. •• i \\ . 24 EXPLANATION OF PLATE XLV. Figs. 1-31. SPIRIFER PELLAENSIS n. sp p. 340 1-3. Pedicle, brachial and anterior views of a large specimen. 4-7. Pedicle, brachial, posterior and anterior views of another specimen. 8-9. Pedicle and brachial views of a very large specimen. 10-11. Brachial and anterior views of a nearly perfect specimen. 12-14. Brachial, pedicle and lateral views of a nearly perfect specimen. (W. M., No. 13571.) Pella Beds, Pella, Iowa. 15-16. Posterior and anterior views of a specimen with a short hinge-line. (W. M.) Pella Beds, Iowa. 17-18. Pedicle and brachial views of a nearly perfect specimen. 19-21. Lateral, brachial and pedicle views of a nearly perfect specimen. (W. M., No. 5771.) Pella Beds, Fort Dodge, Iowa. 22-23. Brachial and posterior views of a nearly perfect specimen, the holotype. 24-25. Posterior and lateral views of another specimen. (W. M., No. 7535.) Pella Beds, Keosauqua, Iowa. 26-27. Pedicle and brachial views of a nearly perfect specimen. 28-29. Pedicle and brachial views of another specimen. (W.M., No. 7247.) Maxville limestone, Fayette County, Pennsylvania. 30. View of an internal cast of a pedicle valve. 31. View of an internal cast of a brachial valve. (W. M., No. 338.) Residual chert, Springfield, Missouri. 106 ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No. 1. PLATE XLV. EXPLAXATIOX OF PLATE XLYL Figs. 1-12. SKUDFIX IXTOEKSCEXS Han 1-5. ffeflkfe. bradnaL latent, posterior and anterior views of a very perfect rprriwtn. 6-ft. Pedicle. hndnaL posterior and anterior riem^ J 42 w ' , ( "S 38 40 44 45 46 47 48 39 49 5O 51 52 53 54 55 56 57 58 59 60 *%->* 'T^ ^* 63 68 64 65 66 67 69 EXPLANATION OF PLATE LXXVIII. Figs. 1-5. ATHYRIS LAMELLOSA (Leveille) p. 465 1. Pedicle view of a nearly complete specimen. (W. M., No. 7605.) Keokuk limestone, Warsaw, Illinois. 2. Pedicle view of a nearly complete internal cast. (W. M., No. 14224.) Residual chert, Cooper County, Missouri. 3-4. Pedicle and posterior views of a nearly complete internal cast. (W. M., No. 7599.) Burlington chert, Louisiana, Missouri. Figs. 6-9. ATHYRIS PAPILIONIFORMIS McChesney p. 468 Pedicle, brachial, lateral and posterior views of a sulphur cast of the holotype. (W. M., No. 13232.) Chester Group, Fountain Bluff, Illinois. Figs. 10-14. ATHYRIS HANNIBALENSIS (Swallow) p. 467 10-12. Lateral, brachial and anterior views of a nearly complete specimen. 13-14. Pedicle and posterior views of another speci- men. (W. M., No. 6690.) Louisiana limestone, Louisiana, Missouri. Figs. 15-20. ATHYRIS LAMELLOSA (Leveille) p. 465 15-16. Views of two pedicle valves upon one of which the lamellar extensions of the shell are well preserved. (W. M., No. 13539.) Fern Glen formation, Fern Glen, Missouri. 17-20. Brachial, pedicle, lateral and anterior views of an exfoliated specimen. (W. M., No. 8545.) Pierson limestone, near Springfield, Missouri. Figs. 21-24. CLIOTHYRIDINA GLENPARKENSIS n. sp p. 473 21-22. Pedicle and lateral views of a nearly complete specimen. 23-24. Brachial and posterior views of another specimen. (W. M., No. 13901.) Fern Glen -formation, Fern Glen, Missouri. Fig. 25. CLIOTHYRIDINA PARVIROSTRA (Meek and Worthen) p. 481 View of the internal cast of a pedicle valve. (W. M., No. 383.) Residual chert, Springfield, Missouri. 174 ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No. 1. PLATE LXXVIII. EXPLANATION OF PLATE LXXIX. Figs. 1-11. CLIOTHYRIDINA OBMAXIMA (McChesney) p. 475 1. View of a large pedicle valve. (W. M., No. 7592.) Fern Glen formation, Monroe County, Illinois. 2-6. Pedicle, brachial, anterior, posterior and lateral views of a nearly perfect specimen! (W. M., No. 13917.) Fern Glen formation, Chautauqua, Illinois. 7-11. Pedicle, brachial, anterior, lateral and posterior views of a nearly perfect specimen. (W. M., No. 7596.) Keokuk limestone, Keokuk, Iowa. Fig. 12. CLIOTHYRIDINA INCRASSATA (Hall) p. 4/7 View of a pedicle valve. (W. M., No. 342.) Burlington limestone, Springfield, Missouri. Figs. 13-16. CLIOTHYRIDINA PROUTI (Swallow) p. 474 Pedicle, brachial, anterior and lateral views of a nearly perfect specimen. (W. M., No. 46951.) Fern Glen formation, near Kimmswick, Missouri. 176 ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No. 1. PLATE LXXIX. 15 EXPLANATION OF PLATE LXXX. Figs. 1-12. CLIOTHYRIDINA TENUILINEATA (Rowley) p. 478 1-3, 4-6. Pedicle, brachial and lateral views of two specimens. (U. M., No. 1358.) Kinderhook, Bed No. 6, Burlington, Iowa. 7-9, 10-12. Pedicle, brachial and lateral views of two specimens, metatypes. (R. R. R.) Burlington white chert, Louisiana, Missouri. Figs. 13-24. CLIOTHYRIDINA HIRSUTA (Hall) p. 479 13-15, 16-18. Pedicle, brachial and lateral views of two specimens. (W. M., No. 13920.) Salem limestone, Hull's Hollow, Madison County, Illinois. 19-21, 22-24. Pedicle, brachial and lateral views of two specimens. (W. M., No. 1369.) Salem limestone, near Boonville, Missouri. Figs. 25-30. CLIOTHYRIDINA LENTICULARIS n. sp p. 480 25-27, 28-30. Pedicle, brachial and lateral views of two specimens. (W. M., No. 12992.) . St. Louis limestone, near Carondelet, Missouri. Figs. 31-60. CLIOTHYRIDINA SUBLAMELLOSA (Hall) p. 482 31-33, 34-36. Pedicle, brachial and lateral views of two young speci- mens having the form and size of C. hirsuta. (W. M., No. 7628.) Chester Group, Chester, Illinois. 37-39, 40-42, 43-45. Pedicle, brachial and lateral views of three young specimens having the general character of C. hirsuta. (W. M., No. 13921.) Lower Chester, Fairview Point, Hardin Co., Illinois. 46-48. Pedicle, brachial and lateral views of an undistorted but somewhat exfoliated specimen. 49-50. Pedicle and lateral views of another specimen. (W. M., No. 7613.) Chester Group, Chester, Illinois. 51-53, 54-56. Pedicle, brachial and lateral views of two specimens partially preserving the surface spines. (W. M., No. 7628.) Chester Group, Chester, Illinois. 57-58. Brachial views of two different specimens. 59-60. Pedicle views of two other specimens. (W. M., No. 14781.) Lower Chester, Fairview Point, Hardin Co., Illinois. Figs. 61-66. CLIOTHYRIDINA PARVIROSTRA (Meek & Worthen) p. 481 61-63. Pedicle, lateral and brachial views of a slightly crushed specimen. (W. M., No. 7611.) Keokuk limestone, Jersey County, Illinois. 64-66. Brachial, lateral and pedicle views of a nearly complete specimen. (W. M., No. 7614.) Keokuk limestone, Warsaw, Illinois. 178 ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No. 1. PLATE LXXX. • * J 1 2345 6 13 14 15 J 7 8 9 1O 11 12 16 17 18 19 2O 21 22 23 24 25 26 27 31 32 33 34 35 36 28 29 3O > I 37 38 39 4O 41 42 43 44 45 46 47 48 49 5O 51 52 53 57 58 54 55 56 59 6O 61 62 63 64 65 66 EXPLANATION OF PLATE LXXXI. Figs. 1-15. COMPOSITA SUBQUADRATA (Hall) p. 489 1-4. Pedicle, brachial, posterior and lateral views of a nearly perfect specimen. 5-8. Anterior, pedicle, brachial and pos- terior views of another specimen. (W. M., No. 7627.) Chester Group, Chester, Illinois. 9-11. Pedicle, anterior and lateral views of a nearly complete specimen. 12-15. Brachial, lateral, anterior and posterior views of a nearly complete specimen. (W. M., No. 13926.) Chester Group, Chester, Illinois. Figs. 16-45. COMPOSITA TRINUCLEA (Hall) p. 486 16-20. Pedicle, brachial, lateral, posterior and anterior views of a very perfect specimen. 21-24. Pedicle, brachial, anterior and posterior views of another specimen. 25-26. Pedicle and brachial views of a third specimen. (W. M., No. 7620.) 27-30. Pedicle, brachial, lateral and anterior views of a nearly per- fect specimen. (W. M., No. 389.) Salem limestone, Spcrgcn Hill, Indiana. 31-34. Lateral, pedicle, brachial and anterior views of a nearly perfect, large example. (W. M., No. 13926.) Salem limestone, Hull's Hollow, Madison County, Illinois. 35-36. Pedicle and lateral views of a very narrow and elongate example. 37-38. Brachial and anterior views of an old shell. 39-42. Pedicle, lateral, anterior and posterior views of a nearly perfect specimen. 43. Brachial view of a nearly perfect specimen. 44-45. Anterior and posterior views of another specimen. (W. M., No. 7617.) Pclla Beds, Pella, Iowa. Figs. 46-51. COMPOSITA LEWISENSIS n. sp p. 488 46-48. Pedicle, brachial and posterior views of a nearly perfect specimen. 49-51. Pedicle, lateral and anterior views of an- other specimen. Cotypes. (D. K. G., No. 203.) Patrick Quarry, Middle Fabius River, Lewis County, Mis- souri. Figs. 52-57. COMPOSITA PENTAGONIA n. sp p. 492 52-54. Posterior, lateral and pedicle views of a very perfect internal cast. 55-57. Anterior, lateral and brachial views of another example. Cotypes. (D. K. G., No. 102.) Residual chert, South Branch, Callaway County, Missouri. \ 80 ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No. 1. PLATE LXXXI. 10 11 12 13 ^^^m^^r 16 17 18 19 2O 14 15 21 22 23 '9^^ 24 25 26 48 27 28 29 30 » 52 53 54 35 46 47 W ll f 36 44 45 41 42 38 EXPLANATION OF PLATE LXXXII. Figs. 1-10. COMPOSITA SULCATA n. sp p. 490 1-5. Pedicle, brachial, lateral, posterior and anterior views of a nearly complete specimen. 6-10. Anterior, posterior, brachial, lateral and pedicle views of a smaller example. Cotypes. (W. M., No. 13782.) Chester Group, Mcadc County, Kentucky. Figs. 11-13. COMPOSITA OPPOSITA (White and Whitfield) p. 494 Pedicle, brachial and lateral views of the holotype. (A. M. N. H., No. 5000-1.) Upper Kinderhook, Burlington, Iowa. Figs. 14-20. COMPOSITA L^VIS n. sp p. 491 14-17. Pedicle, brachial, lateral and posterior views of a very per- fect specimen. 18-20. Pedicle, brachial and anterior views of another specimen. Cotypes. (D. K. G., No. 303.) Chester Group, Breckinridgc Co., Kentucky. Figs. 21-26. COMPOSITA GLOBOSA n. sp p. 493 21-23. Pedicle, lateral and anterior views of a nearly perfect speci- men. 24-26. Brachial, posterior and anterior views of another specimen. Cotypes. (W. M., No. 3003.) Keokuk limestone, near Springfield, Missouri. Figs. 27-38. NUCLEOSPIRA BARRISI White p. 455 27-31. Pedicle, brachial, posterior, anterior and lateral views of a nearly complete specimen. 32-33. Exterior and interior views of a pedicle valve. 34-35. Exterior and interior views of an- other pedicle valve. 36. View of a pedicle valve. 37. View of a brachial valve. 38. Interior view of an imperfect brachial valve. Cotypes. (U. M., No. 1360.) Kinderhook, Bed No. 7, Burlington, Iowa. Figs. 39-42. NUCLEOSPIRA OBESA Rowley p. 457 39-41. Pedicle, brachial and lateral views of a metatype. 42. Brachial view of the same specimen enlarged (x3). (R. R. R.) Burlington white chert, Louisiana, Missouri. Figs. 43-48. NUCLEOSPIRA ROWLEYI n. sp p. 454 43-44, 45-46, 47-48. Pedicle and brachial views of three different individuals, enlarged (x 4). Cotypes. (W. M., No. 6733. Louisiana limestone, Louisiana, Missouri. Figs. 49-60. NUCLEOSPIRA MINIMA Weller p. 456 49-54. Views of six separate valves. 55-60. Views of the same valves enlarged (x4). Cotypes. (W. M., No. 11349.) Glen Park limestone, Glen Park, Missouri. Figs. 61-63. CAMAROPHORELLA LENTICULARIS (White and Whitfield) .. .p. 459 61. View of an internal cast of a pedicle valve. 62-63. Views of two internal casts of brachial valves. Cotypes. (U. M., No. 1356.) Kinderhook, Bed No. 5, Burlington, Iowa. 183 Figs. 64-69. ROWLEYELLA FABULITUS (Rowley) p. 463 64. Pedicle view of a nearly complete specimen from which the shell is partially removed, showing the median septum. The spiral brachidium is clearly shown in this specimen, but does not appear in the photograph. 65-66. Pedicle and brachial views of the same specimen enlarged (x4). 67. Pedicle view of a smaller specimen from which the shell has been removed on each side. 68-69. Pedicle and brachial views of the same specimen (x4) showing the median septum in each valve. (W. M., No. 14279.) Burlington white chert, Louisiana, Missouri. Figs. 70-79. CAMAROPHORELLA MTSSOURIENSIS (Winchell) p. 460 70-73. Pedicle, brachial, lateral and anterior views of the holotype. (U. M., No. 1993.) 74-76, 77-79. Pedicle, brachial and lateral views of two specimens, metatypes of Seminula buckleyi Row- ley. (R. R. R.) Louisiana limestone, Louisiana, Missouri. 184 ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No. 1. PLATE LXXXII. 11 12 13 :x 8 9 10 " 28 29 30 31 23 32 34 36 37 33 35 38 ) J • 43 44 45 46 47 48 55 39 40 41 42 > s s 49 51 53 * 56 57 61 62 63 ;• * > 58 5O 54 52 68 69 59 6O 65 64 66 67 7O 71 72 73 74 75 J > j 76 77 78 79 EXPLANATION OF PLATE LXXXIII. Figs. 1-2. SPIRIFER FORBESI Norwood and Pratten p. 331 Views of two separate brachial valves. (W. M., Nos. 5654 and 13531.) Burlington limestone, Springfield, Missouri, and Burling- ton, Iowa. Figs. 3-5. BRACHYTHYRIS PECULIARIS (Shumard) p. 381 Pedicle, brachial and lateral views of a very perfect specimen. (W. M., No. 14780.) Chouteau limestone, Calhoun County, Illinois. Fig. 6. BRACHYTHYRIS BURLINGTONENSIS n. sp p. 371 Brachial view of an internal cast. (W. M., No. 7501.) Kinder hook, Bed No. 5, Burlington, Iowa. Figs. 7-8. RHIPIDOMELLA BURLINGTONENSIS (Hall) p. 149 Interior views of the pedicle and brachial valves of one individual. (W. M., No. 7858.) Burlington limestone, Burlington, loiva. Figs. 9-10. RHIPIDOMELLA DUBIA (Hall) p. 160 Interior views of a pedicle and a brachial valve. (W. M., Nos. 7846 and 11927.) Salem limestone, Colesburg, Kentucky, and Spergen Hill, Indiana. Fig. 11. SCHELLWIENELLA INFLATA (White and Whitfield) . p. 59 View of an internal cast of a pedicle valve. (W. M., No. 14759.) Kinderhook, Bed No. 7, Burlington, Iowa. Figs. 12-13. PRODUCTUS INDIANENSIS Hall p. 131 Pedicle and lateral views of the holotype. (A. M. N. H., No. 5087) Salem limestone, Spergen Hill, Indiana. Figs. 14-17 PRODUCTUS MESIALIS Hall p. 112 14-16. Pedicle, posterior and lateral views of a pedicle valve. 17. View of an impression of the exterior of a brachial valve. Co- types. (A. M. N. H., No. 5090.) Keokuk limestone, Nauvoo, Illinois. Figs. 18-20. PRODUCTELLA SUBL^VIS n. sp p. 102 18-19. Views of the more or less modified internal casts of two pedicle valves. 20. View of an incomplete external impression of a brachial valve. (W. M., No. 10558.) Kinderhook sandstone, Kinderhook, Illinois. Figs. 21-22. CHONOPECTUS FISCHERI (Norwood and Pratten) p. 96 21. View of the internal cast of a large pedicle valve. 22. View of an impression of the pedicle valve showing the cardinal spines. (W. M., No. 14779.) Chonopectus sandstone, Burlington, lozva. 186 ILLINOIS STATE GEOLOGICAL SURVEY. MONOGRAPH No. 1. PLATE LXXXIII. 8 12 13 1O 16 I 14 DAY USE RETURN TO DESK FROM WHICH BORROWED EARTH SCIENCES LIBRARY This book is due on the last date stamped below, or on the date to which renewed. Renewed books are subject to immediate recall. JUN 121969 JUL 713G9 OCT 101C39 JAtHMHSTO APR ] 5 197 0 iUL 7"1S7f> nr.T 1 6 1970 JAN 21 J971 APR 1 a ]°fj\ JUN 2 ,q 1971 OCT 14 19/1 JAW °' •c""> SE5 LD 21-40m-5,'65 (F4308slO)476 General Library University of California Berkeley U. C. BERKELEY LIBRARI CDblE7b7SS