PLATE -27. 

 Fig. 1 a, b. 472. 6. Avicula emacerata. ( Pag. 83.) 



Fig. 2. 473. 7. AvicuLA bhomboidea. (Pag. 81.) 



2 o. A large individual, in which the anterior wing is le.s.s prmninent than usual. 

 2 6. A smaller si)cclnien. 



2 c. A young specimen, having the lungtjj nearly eiiual to the lieight. 



2d. The posterior portion of anotlier specimen, having the stria' more perfectly preserved and the angle of 

 the wing more extended. 



Fig. 3, 12. 480. 1. Pyrenomoeus cuneatus. ( Pag. 87.) 



3. This specimen, though differing to some extent inform, I have referred to the same species. It retains 

 the shell, which is fiiintly striated, the beak remarkably elevated, and the anterior extremity abruptly 

 rounded. 



12 a, b. The casts of ojjpositc valves of specimens nearly of the same size. 



12 c. The cast of a large individual, showing several prominent folds parallel to the linos of growtli. 



Fig. 4. 479. 1. POSIDONIA? ALATA. ( Pag. 87.) 



Fig. 5, 6. 474. 19. Modiolopsis subalatits. ( Pag. 84.) 



5. A fragment of slate, with figures of the right and left valve. 

 6 o, 6. Figures of the right valve of two specimens of large size. 



Fig. 7. 475. 6. Tellinomya lata. (Pag. 85.) 



Fig. 8, 9. 476. 7. Tellinomya mach^eriformis. (Pag. 85.) 



8 a. The left valve of an individual of ordinary size. 8 b. The right valve of a large individual. 



8 c. The right valve of a smaller individual. 



8 d. A small portion of the surface much enlarged, showing the concentric strise. 



9. (Cypricardia angusta, Geol. Rep. 4th District, pag. 76, fig. 6.) 



Fig. 10, 13. 477. 8. Tellinomya curta. ( Pag. 86.) 



Fig. 11. 478. 4. Orthonota curta. (Pag. 86) 



11 a. The right valve of a specimen of natural size and proportions. 

 11 4. A specimen of the left valve, narrowed by pressure. 



