PLATE 82. 

 Ficr. 1. 351. 11. MoDioLOPsis MODioLARis. (Pag. 294.) 



A young specimen of this species. 

 Fig. 2. 353. 13. Modiolopsis curta. (Pag. 297.) 



2 a. A sjiecimen from Loraine, Jefferson cnuntv, New-Yovk. 

 2 4. A small specimen in sliale, from Rodman, Jeffei-son county. 



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



Fio-. 3. 355. 15. Modiolopsis anodontoides. ( Pag. 298.) 



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



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

 extremity. 3 c. A si>ecimen in shale, where both valves are still adhering. 



Fig, 4. 202. 3. Modiolopsis FABA. (Pag. 298.) 



-I a, b. Views of two specimens — casts in sandstone. 



Fig. 5. 356. 16. Modiolopsis ? NuctTLTFOKMis. Pag. 298.) 



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



Fig. 6. 357. 1. Oethonota pholadis. (Pag. 299.) 



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



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



7 b. 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 sliows the folds upon the 



cardinal line. 



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



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



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



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



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

 9 b, c, d. Other individuals from ditierent localities, showing a slight difference in form. 



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



Fig. 10. 190. 2. Nucula? poststruta. (Pag. 301.) 



10 a. A small specimen in the ferruginous sandstone. 



10 b. A larger specimen, preserving very distinctly the strise on the posterior slope. 



Fig. 11. 361. 1. Lyrodesma plana. (Pag. 302.) 



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



Fig. 12. 362. 2. Lyrodesma pitlchella. (Pag. 302.) 



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

 12 6. The same eiilareed, showing the character of the crenulations. 



12 c. A smaller specimen from tlie partially altered slates near Waterford on the Hudson rivei'. 

 12 d. The cardinal line enlarged. 



