PLATE 4. 



Fig. 1. 387. Ch^tetes ? ( Pag. 7.) 



Fig. 2. 38S. 12. LiNGULA crKEATA. (Pag. 8.) 



2 a. A specimen of large size, nearly destitute of a shell. 



2 4. A small fragment of sandstone, showing upon its surface three individuals of different sixc. 



2 c. A small individual, preserving the shell nearly entire. The two last are associated with a small species 



of Cythekina, fig. 8. 

 2 f. A small fragment from a slab of sandstone, where the Li.ngdl.e have hoen drifted hy the waves, Fn in 



the Ix'.ik of each one extends a small ridge of stone which accumulated here, protected by the .'shell 



during the receding of the wave. 



Fig. 4, 5. 389. 22. Atrypa oblata. (Pag. 9.) 



4 a. View of the ventral valvr. 4 b. View of base. 4 c. Profile view. 



5. The dorsal or larger valve imbedded in sandstone, which covers the lower part of the shell. It is impossi- 

 ble to say positively that this is identical with the preceding; but the partially imbedded specimen 

 affords no positive characters to distinguish it. 



Fig. 6. 390. 23. Atrypa plicata. (Pag. 10.) 



Fig. 7. 39.5. 15. Murciiisonia? conoidea. (Pag- 13.) 



Fig. 8. 400. 2. Cythf.rina cylindricji ( Pag. 14.) 



