PLATE 82. 



Fig. 1. 361. 11. MoDioLopsis modiolaris. (Pag. 294.) 



A young specimen of this species. 



Fig. 2. 363. 13. Modiolopsis curta. (Pag- 297.) 



3 a. A specimen from Lorainfc, JeflTerson county, New-York. 

 2 6. A small »))ccimen in shale, from Rodman, .leflcrson rounty. 



2 e. Figure of a small specimen from Mineral Point, Wisconsin. 2 d. Cardinal view of the same species. 



Fig. 3. 355. 16. Modiolopsis ahodontoides. ( Pag. 298.) 



3 o. A specimen in sandstone, preserving the original form of the shell. 



3 6. A specimen in soft shale, more compressed than the preceding, and consequently rounded at the posterior 

 extremity. 3 c. A specimen in shale, where both valves are still adhering. 



Fig. 4. 202. 3. Modiolopsis faba. (Pag. 298.) 



4 a, ft. Views of two specimens — casts in sandstone. 



Fig. 6. 356. 16. Modiolopsis? nuculifohmis. Pag. 298.) 



5 a. Specimen preserving both valves. 5 ft. A right valve, less compressed than the preceding. 



Fig. 6. 367. 1. Orthonota pholadis. (Pag. 299.) 



Fig. 7. 358. 2. Orthonota parallela. (Pag. 299.) 



7 a. The left side of a cast scarcely retaining any markings. 7 d. Dorsal view of the same. 



7 ft. Dorsal view of a cast in coarse sandstone, where the folds are visible on the dorsal margin. 



7 e. The left valve, preserving the shell, which is finely striated concentrically, and shows uie folds npon the 



cardinal line. 



Fig. 8. 359. 3. Orthonota contracta. (Pag. 300.) 



8 a. The left valve, showing the distinct carina and concentric strise of the surface. 



8 6. Dorsal view of the same, showing the oblique wrinkles on the posterior cardinal margin of tlte shell. 



Fig. 9. 360. 1. Cleidophorus planulatus. (Pag. 300.) 



9 a. Specimen of arenaceous slate, with several individuals of this species, associated with crinoidal columns. 

 9 ft, e, d. Other individuals from different localities, showing a slight difference in form. 



9 e. A specimen from the altered slates, preserving both vidves. 



Fig. 10. 190. 2. NuculaI poststriata. (Pag. 301.) 



10 a. A small specimen in the ferruginous sandstone. 

 10 ft. A larger specimen, preserving very distinctly the stria on the posterior slope. 



Fig. 11. 361. 1. LvRODESHA PLANA. (Pag. 302.) 



11 a. The right valve. U ft. Interior of the same, showing the cardinal teeth. 



Fig. 12. 362. 2. Lyeodesma pulchella. (Pag. 302.) 



12 a. A specimen of the natural size, from the black slate near Watertown, Jefferson county. 

 12 ft. The same enlarged, showing the character of the crenulations. 



12 e. A smaller specimen from the partially altered slates near Waterford on the Hudson river. 

 \i d. The cardinal line enlarged. 



