OF CONCHOLOGY. 279 



extremity subangular ; posterior side cuneate, extremity acutely 

 rounded ; sculpture consisting of fine raised concentric lines ; 

 lunule large, cordate. 



Locality. — Virginia or Maryland. 



Remarks. — This species is most nearly allied to C. subnasuta, 

 but is much larger, more oblique, more inequilateral, and the 

 concentric lines more prominent. 



CRASSATELLID^]. 

 CARDITAMERA, Conrad. 

 C. RECTA. PL 20, fig. 2. 



Description. — Trapezoidal, very inequilateral, elongated ; dor- 

 sal and ventral margins parallel ; dorsal line emarginate towards 

 the end, which is truncated ; posterior margin obliquely truncated 

 above or slightly emarginate ; ribs 16, flattened on the anterior 

 side, profoundly elevated posteriorly and squamose, valves con- 

 tracted medially ; ventricose over the umbonal slope. 



Locality. — Charles Co., Md. Prof. Cope. 



Remarks. — Differs from C. protracta in being proportionally 

 longer, with more elevated ribs, and in the emarginate posterior 

 end. 



TRIASSLC. 

 ASTARTE. 

 A. veta, Conrad. PI. 20, fig. 5. 



Description. — Ovate, from ventral margin to beak compressed, 

 equilateral ; beaks prominent, oblique ; anterior ventral margin 

 rounded, posterior obliquely truncated ; posterior end truncated 

 and situated much above the line of the base. (Cast.) 



Locality. — South River, N. J. 



This species is nearly allied to, if not identical with, Astarte 

 Triasina, Dunker. 



A. annosa, Conrad. PI. 20, fig. 4. 



Description. — Suborbicular, convex, very inequilateral, ven- 

 tral and anterior margins regularly and nearly equally rounded ; 

 posterior end truncated, direct. (Oast.) 



Locality. — Occurs with the preceding. 



Remarks. — These two casts I found in the ash-colored clay 

 near Washington, Middlesex Co., N. J. This clay was by 

 Rogers considered as the lowest part of the cretaceous forma- 

 tion ; but I have ascertained it to be Triassic. It contains abun- 

 dant stems and leaves of Cyclopteris. 



