PLATE 4 (bis). 



Fig. 1. 391. 17. MoDioLOPsis okthonota. (Pag. 10.) 



1 a. Right valve of a small specimen, with the posterior extremity rounded and the anterior one extended. 

 1 b. Right valve of a larger specimen, having the anterior extremity less prolonged. 



1 c. View of the hinge-line and cardinal area of the last. 



F'ig. 2. 392. 18. MoDioLorsis? primigenius. ( P^g- H-) 



2 a. A small specimen, with the beak very prominent, and almost vertically truncated at the posterior ex- 



tremity. 

 2 6. A cast having the markings almost entirely obliterated, and showing a fold or depression along the 



hinge-line. 

 2 c. A specimen partially preserving the shell, which is alated on the posterior dorsal margin, and slightly 



acute in front. 

 2 (i. A fragment preserving an impression of the shell, showing the concentric and radiating lines. 



2 e. A portion of the same enlarged. 



Fig. 3. 393. 19. Pleup.otomakia? pervetusta. ( Pag. 12.) 



3 a. Profile view of a specimen. 3 b. View of the base. 3 c. View of the apex. 



3 d. A fragment of the sandstone containing numerous individuals of this species, with Bucania trilolata. 



Fig. 4. 394. 20. Pleukotomaria litorea. (Pag. 12.) 



4 a. Profile view of specimen. 4 b. View of the apex. 



Fig. 5. 396. 7, Bucania trilobatus. ( Pag. 13.) 



5 a. Side view of a specimen. 5 b. Dorsal view of the same. 



3 d. Tiic upper flgarc in this specimen, and the lower lefthand figure, are of this species. 



Fig. 6. 397. 2. Oncoceras gibbosum. (Pag. 13.) 



6 a. Ventral view of the specimen. G 6. Lateral view. 6 c. Section of same. 



Fig. 7. 398. 26. Orthoceras . ( Pag. 14.) 



7 a. Lateral view of the fragment. 7 b. Section showing position of siphuncle. 



Fig. 8. 399. 27. Orthoceras multtseptum. ( P^g. 14.) 



8 a. A fragment of a small specimen, showing a part of the outer chamber. 



8 6. A fragment of a larger specimen, showing the commeneemeni of the outer chamber, with a narrow one- 

 at the termination of the otliers. 



