PLATE 31. 



Fig. 1. 500. 3. Pentamerus ovalis. ( Pag. 103.) 



1. A small valve, having a width slightly greater than the length. 



1 a. A larger valve, having a length nearly once and a half the width. 



Fig. 2. 446. 21. Leptxna obscuba? (Pag. 103.) 



Fig. 3. 501. 1. Platyostoma. (Pag. 103.) 



8 a. A large specimen of this .species, having a portion of the last volution broken off. 



3 i. A smaller specimen, with the expanded portion of the last volution broken oil'. 



Fig. 4. 502. 31. Orthoceras clavatum. ( Pag. 104.) 



4 o. A fragment near the smaller extremity of the shell. 



4 6. A smaller fragment preserving a portion of the outer chamber. 



Fig. 5 a, b. 503. 1. Homalonotus delphinocepiialus. (Pag- 104.) 



Fig. 6. 504. Fragment of Ichthyodorulite. (Pig- 104.) 



Fig. 7. Fragment of the rib of some vertebrate animal? ( Pag. 105.) 



