PLATE 82, 
Fig. 1 . 351. 11. Modiolopsis modiolaris. 
A young specimen of this species. 
(Pag. 294.) 
Fiff. 2. 
353. 13. Modiolopsis curta. 
2 a. A specimen from Loraine, Jefferson county, New-York. 
2 b. A small specimen in shale, from Rodman, Jefferson county. 
2 c. Figure of a small specimen from Mineral Point, Wisconsin. 
(Pag. 297.) 
2 d. Cardinal view of the same species. 
Fig. 3. 355. 15. Modiolopsis anodontoides. ( Pag. 298.) 
3 a. A specimen in sandstone, preserving the original form of the shell. 
3 b. 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, b. Views of two specimens — casts in sandstone. 
Fig. 5. 356. 16. Modiolopsis? nuculiformis. Pag. 298.) 
5 a. Specimen preserving both valves. 5 b. A right valve, less compressed than the preceding. 
Fig. 6. 357. 1. Ortiionota pholadis. (Pag- 299.) 
Fig. 7. 358. 2. Ortiionota parallela. (Pag- 299.) 
7 a. The left side of a cast scarcely retaining any markings. 7 d. 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 c. The left valve, preserving the shell, which is finely striated concentrically, and shows the folds upon the 
cardinal line. 
Fig. 8. 359. 3. Ortiionota contracta. (Pag- 300.) 
8 a. The left valve, showing the distinct carina and concentric striae of the surface. 
8 6. Dorsal view of the same, showing the oblique wrinkles on the posterior cardinal margin of the 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 b, c, d. Other individuals from different localities, showing a slight difference in form. 
9 e. A specimen from the altered slates, preserving both valves. 
Fig. 10. 190. 2. Nucula? poststriata. (Pag- 301.) 
10 a. A small specimen in the ferruginous sandstone. 
10 b. A larger specimen, preserving very distinctly the striae on the posterior slope. 
© 
Fig. 11. 
11 a. The right valve. 
361. 
1 . 
Lyrodesma plana. (Pag. 302.) 
11 b. Interior of the same, showing the cardinal teeth. 
Fig. 12. 362. 2. Lyrodesma pulchella. 
12 a. A specimen of the natural size, from the black slate near Watertown, Jefferson county. 
12 b. The same enlarged, showing the character of the crenulations. 
12 c. A smaller specimen from the partially aKered slates near Waterford on the Hudson river. 
12 d. The cardinal line enlarged. 
(Pag. 302.) 
