Fig. 1. 
PLATE 82. 
351. 11. MoptoLopsis MopioLaris. (Pag. 294.) 
A young specimen of this species. 
Eig. 2: 
2 a. 
2b. 
aCe. 
Fig. 3. 
353. 13. MopioLopsis curTa. (Pag. 297.) 
A specimen from Loraine, Jefferson county, New-York. 
A small specimen in shale, from Rodman, Jefferson county. r j 
Figure of a small specimen from Mineral Point, Wisconsin. 2d. Cardinal view of the same species. 
355. 15. MopioLopsis aNODONTOIDES. ( Pag. 298.) 
3 a. A specimen in sandstone, preserving the original form of the shell. 
3b. A specimen in soft shale, more compressed than the preceding, and consequently rounded at the posterior 
extremity. 3c. A specimen in shale, where both valves are still adhering. 
Fig. 4. 202. 3, MopioLopsis FaBA. (Pag. 298.) 
4 a,b. Views of two specimens — casts in sandstone. 
Fig. 5. 356. 16. Mopiotopsis? NUCULIFORMIS. Pag. 298.) 
5 a. Specimen preserving both valves. 5 6. A right valve, less compressed than the preceding. 
Fig. 6. 357. 1. OnrHoNnoTa PHOLADIs. *  “(Pap. 2995) 
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. 
7b. Dorsal view of a cast in coarse sandstone, where the folds are visible on the dorsal margin. 
VEC 
Fig. 8. 
The left valve, preserving the shell, which is finely striated concentrically, and shows the folds upon the 
cardinal line. 
359. 3. ORTHONOTA CONTRACTA. (Pag. 300.) 
8 a. The left valve, showing the distinct carina and concentric strie of the surface. 
8 b. Dorsal view of the same, showing the oblique wrinkles on the posterior cardinal margin of the shell. 
Pipe go: 
360. 1. CLEImMmoPHORUS PLANULATUS. (Pag. 300.) 
9 a. Specimen of arenaccous slate, with several individuals of this species, associated with crinoidal columns. 
9 6, ec, 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. Nucuza? PosTSTRIATA. (Pag. 301.) 
10 a. A small specimen in the ferruginous sandstone. 
10 6. A larger specimen, preserving very distinctly the strig on the posterior slope. 
Fig. 11. 361. 1. LyRopEsMA PLANA. (Pag. 302.) 
11 a. The right valve. 11 b. Interior of the same, showing the cardinal teeth. 
Fig. 12. 362. 2. LyropESMA PULCHELLA. (Pag. 302.) 
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 ¢. A smaller specimen from the partially altered slates near Waterford on the Hudson river. 
12 d. The cardinal line enlarged. 
