PLATE 4 (bis). 



Fig-. 1. 2S. 1. LePTJENA PLICIFERA. (Pfig- 19-) 



1 a. Figure of the convex valve. 

 1 /(. Cast lit' convex valve, with a portion of the shell rcmaininR : cast of visceral cavities mapnifieii. 



Fio-. 2. 29. 2. Leptjena incrassata. (Pag- 19-) 



2 a, b. Convex valves of this species. 2 e. Ventral valves. 



2 d. Cast of the interior of the convex valve, and the same enlarged. 



Fig. 3. 30. 3. Leptj-ena fasciata. (Pag. 20.) 



3 a, b. Convex valves of two individuals. 3 c. A larger specimen of the same. 



Fig. 4. 31. 1. Orthis costalis. (Pfig- 20.) 



\ a An imperfect shell, showing the radii towards the margin. 



1 b. A cast allowing the visceral marking, and casts of radii near the base of the shell. 



4 c. An impression of the convex valve, smaller than the other specimens. .Such impressions are abundant. 



Fig. 5. 32. 1. Atrypa dubia. (Pfig- 21.) 



Fig. 6. 33. 2. Atrypa acutirostra. (Pag- 21.) 



The two lower figures are of the natural size ; the upper one is enlarged. 



Fig. 7. 34. 3. Atrypa pleka. (Pag. 21.) 



7 a. View of the ventral valve, showing the beak of the dorsal valve closely incurved over the beak of the 



former. 1 h. Lateral view of the same individual. 



1 c. Doi-sal valve of a small specimen. 



I (I. Front view of a large specimen. ^ e. Dorsal valve of the same. 



Fig. 8. 35. 4. Atrypa plicifera. (Pag. 22.) 



8 n, b. View of ventral valve, and front of same individual. 

 '^ r, d. Ventral valve and front view of another individual. 



Fig. 9. 36. 5. Atrypa altilis. (Pag. 23.) 



II a. View of the ventral valve, showing the beak of the dorsal valve. '.i b. View of the dorsal valve, 

 '.p r. Lateral view of the same shell. 9 d. Front view, show'ing the elevation of the mesial radii. 



Fig. 10. 37. 1. Orbicula? deformis. (Pag- 23.) 



Fig. 11. 38. I. Metoptoma? dubia. (Pag. 23.) 



Fig. 12. 39. 1. Ill^enus arcturus. (Pag. 23.) 



Fig. 13. 40. 2. Illvenus crassicauda? (Pag. 24.) 



Fig. 14. 41. 1. AsAPHUs? obtusus. , (Pag. 24.) 



Fig. l.*). 42. 2. AsAPHirs marginalis. (Pag. 24.) 



Fig. 16. 43. 1. Isoteuis gigas? ■ (Pag- 25.) 



Fig. 17, IR, 19. 44. 2. Isotelus canalis. (Pag. 25.) 



IS & I'J l,;iliniMi nr epislnm.! r.l .m linlilus, |ierh,i]is ol /. lunnlis. 

 Fig. 20. l-'ii. 1. Geraurus? (Spacics uvdctrrvirned). (Pag. 25.) 



Fig. 21. A f'ragiTKMit of thf crust nf an unknown trilobit(>. 



