130 MR. CONRAD'S DESCRIPTIONS 



PELAGUS. 



P. VANUXEMi. PI. 14, fig. 15. — Length 2|. Diameter 1 5-16. 



PECTEN. 



P. ELixATus. PI. 14, figs. 13, 14. — Suborbicular ; inferior valve ventricose, with fourteen wide, elevated, 

 rounded ribs and concentrically wrinkled ; superior valve flat ; ears equal. 



Locality. Near Santee Canal, South Carolina, in white friable limestone, (Upper 

 Eocene.) 



Lower Eocene Species. 

 CARDITA. 



C. DENSATA. PI. 14, fig. ^4. — Obliquely cordate, ventricose, thick, with about twenty-five flattened costse 

 obsolete towards the base, narrow, profound, elevated and crenulated on the umbo ; umbo very 

 prominent at the apex ; anterior basal margin obliquely subtruncated ; posterior extremity truncated, 

 direct; cardinal area very thick and dilated, the teeth oblique. Height \% inch. Length the same. 



Locality. Claiborne, Alabama. 



This pretty species abounds in entire specimens in the argillaceous stratum near 

 low water mark in the Claiborne Bluff. I found none in the upper beds. Compared 

 with C. planicosta, it is much smaller, comparatively shorter, thicker, and may 

 always be readily distinguished by the crenulated ribs on the umbo. 



CYTHEREA. 



C. suBiMPRESSA. PI. 14, fig. 26. — Ovate, slightly ventricose, smooth and polished, with concentric slightly 

 impressed lines on the anterior side ; anterior side short, rather acutely rounded ; posterior side 

 produced, acutely rounded at the extremity ; dorsal margin long, oblique, slightly curved ; beaks 

 prominent; lunule lanceolate, defined by a slightly impressed line. Length 1^ inch. Height 8-10 

 inch. 



Locality. Marlbourne, Hanover county, Virginia. Mr. Ruffin. 



This species may be distinguished from C. cequorea, by its greater comparative 

 length, smaller size, and in wanting the strong furrows of that species. Mr. Ruffin 

 obtained several entire specimens. 



C. LENis. PI. 14, fig. 19. — Longitudinally ovate, thin, ventricose; anterior extremity acutely rounded; 

 posterior end direct, subtruncated ; disk with impressed concentric lines, distinct on the sides but 

 obsolete in the middle of the valves; lunule long, cordate, defined by an impressed line ; inner margin 

 entire. 



Locality. Occurs with the preceding. 



