PLATE 83. 

 Fig. 1. 236. 13. MuECHisoNiA gracilis. (Pag. 303.) 



1 a. A specimen (a cast) from the calcareous sandstone. 1 b. A similar cast from the soft shales at Loraine. 



1 c. A fragment of slate, with several small specimens. 



Fig. 2. 363. 14. Muechisonia uniangulata, rar. ABBttEviATA. (Pag. 304.) 



2 a, b. Two specimens which preserve a part of the shell. 



2 c* A portion of the surface of the last volution magnified, showing the double spiral band. 



2 d. A specimen with the volutions more acutely angulated, but apparently identical. 



Fig. 3. 225. 13. Pledeotomaria subconica. (Pag. 304.) 



3 a. A specimen preserving the vertical striae. 3 J. A portion of the same enlarged. 

 3 c, d. Imperfect casts, from the shales of the Hudson-river group. 



3 e. A more perfect cast of the same species, from Wisconsin. 



Fig. 4. 364. 17. Pleurotomaria [?] bilii. (Pag. 30-5.) 



4 a. A small specimen of this species, showing the back of the spire, and the expansion of the last volution 



towards the aperture. 

 4 b. A portion of the surface enlarged, showing the alternating larger and smaller carina, which are crossed 



by the oblique fine stris. 

 4 e. A larger specimen : a view from the outside obliquely into the aperture. 

 4 d. Another specimen, showing the form of the aperture, whicli is entire on the outer margin. 

 4 e. The base, viewed in the direction of the spire. 



Fig. 5. 365. 18. Fh-EvnoTOUAmA (Species undetermined). (Pag. 305.) 



.5 a, b. Views of the apex and base of two small casts. 



Fig. 6. 366. 2. Metoptoma? eitgosa. (Pag. 306.) 



6 a. Upper surface of the sliell. 6 b. Lateral view. 6 e. Enlarged portion of the surface. 



Fig. 7. 239. 2. Caeinaropsis patelliformis. (Pag. 306.) 



"J a. A large individual of this species. 



7 b. Profile of the same. Tlie elevation of the sliell is less tlian usual, from compression. 



Fig. 8. 367. 3. Carinaeopsis oebiculatus. (Pag. 306.) 



8 a. View of a specimen, looking upon the apex. S b. Lateral view of specimen partially distorted. 



8 e. A portion of the surface enlarged. 



Fig. 9. 240. 1. Bellerophon bilobattjs. (Pag. 307.) 



9 a. A large imperfect specimen. 



9 4, c. Lateral and profile view of a smaller specimen, showing the volutions compressed. 



Fig. 10. 368. 4. Bellerophon cancellatus. (Pag. 307.) 



10 a. Lateral view of an entire individual. 



10 b. A portion of the surface enlarged, showing the cancellated striae. 



10 c. A fnigmcnt "f a shell, apparently of Ihe same species. 



