PLATE XVI—Continued. 
Chonetes coronata, Conrad. 
Fig - . 10. A view of the brachial valve ; showing the cardinal area and deltidium. 
Fig. 11. A pedicle-valve with unusually strong concentric growth-lines. 
Hamilton group. Darien, N. Y. 
Fig. 24. The interior of a brachial valve; showing the cardinal process, muscular scars and brachial 
ridges. 
Hamilton group. York, N. Y. 
Fig. 26. The interior of another brachial valve ; showing more distinctly the quadripartite character of the 
cardinal process. 
Fig. 33. The interior of a pedicle-valve; showing the cardinal area, teeth and muscular scars. 
Hamilton group. Western New York. 
Genus STKOPHALOSIA, King. 
(See Plates XVb, XVII, XVIIa.) 
Page 314. 
Strophalosia muricata, Hall. 
Fig. 12. The exterior of the pedicle-valve, from a gutta-percha impression of a natural mould ; showing the 
short spines on the surface. 
Fig. 16. Two views of a pedicle-valve; showing the cicatrix of attachment. 
Fig. 30. The interior of a brachial valve, from a gutta-percha impression; showing the cardinal process, 
brachial ridges and median septum. 
Fig. 38. An internal cast of the pedicle-valve ; showing the muscular impressions. 
Fig. 42. An enlargement of the muscular scars restored from several internal casts of the pedicle-valve. 
Chemung group. Meadville, Pennsylvania. 
Genus CHONOSTKOPHIA, gen. nov. 
'(See Plate XVb.) 
Page 310. 
Chonostrophia complanata, Hall. 
Fig. 13. The interior of the pedicle-valve from a gutta-percha impression ; showing the reversed convexity 
of the shell, the flabellate muscular area, conspicuous median septum, and the cardinal spines. 
Fig. 29. Another interior of a similar valve in which the cardinal spines are apparently absent. 
Oriskany sandstone. Albany county, N. Y. 
Genus CHONETES, Fischer de Waldheim. 
Page 303. 
Chonetes hemisph^rica, Hall. 
Fig. 14. A view of the pedicle-valve? showing its great convexity. 
Schoharie grit. Albany county, N. Y. 
Chonetes arcuata, Hall. 
Fig. 15. Profile of a pedicle-valve, from which the radiating striae have been accidentally omitted in litho¬ 
graphing. 
Figs. 35, 36. Two views of an internal cast of the pedicle-valve ; showing the muscular impressions and the 
crenulation of the cardinal area, caused by the casts of the spine-tubes. 
Corniferous limestone. Near Williamsville, N. Y. 
Genus CHONOPECTUS, gen. nov. 
(See Plate XVb.) 
Page 312. 
Chonopectus Fischeri, Norwood and Pratten. 
Fig. 17. The exterior of a pedicle-valve ; showing the concentrically reticulate surface. 
Fig. 31. An enlargement of the surface ; showing the double series of concentric wrinkles crossing the fine 
radiating striae. 
Yellow sandstones. Burlington, Iowa. 
