PLATE 94. 



Page 



Fig. 1 a - d. Lept^na? nucleata. 419 



1 a, b. Ventral and profile views of tlic cast. 



1 c. Cardinal view. 



1 d. Profile view enlarged. 



Fig. 2 a - d. Steophodonta magnifica. 414 



2 a. The impression of the dorsal valve of this species in sandstone. The cavities of the car- 

 dinal process arc not shown in the figure. 



2 6. A cast taken from a similar mould, showing the diverging divisions of the cardinal process, 

 crenulated hinge-line, muscular impressions, etc. ( The details of the marking are not 

 well shown in this figure.) 



2 e, d. The impressions of the same in sandstone, the marking being preserved in different 

 degrees of perfection in the two specimens. 



Fig. 2e, /, &3. Strophomena RUGOSA, rar. ventricosa. 417 



2 c. A east taken from the impression of a dorsal valve in sandstone. 

 2/. An impression of the dorsal valve in sandstone. 



8. A cast in sandstone of the ventral valve. The specimen has heen weathered, and the parts 

 are not so salient as they otherwise would be : the hinge-line is obliterated in the speci- 

 men. 



Fig. 4. Orthis iiipPARiONTX. 407 



4. The cast of the dorsal valve of a young shell of this species. 



