PLEIOG'ENE FOSSILS. 77 



A single rather imperfect valve is all that we have as yet found in the State. It is 

 sufficiently well preserved, however, to leave no doubt of its specific identity with the 

 recent species of the coast. Conrad has described two species of this genus, P. crassi- 

 dens and P. arenosa, from the Meiocene of Virginia, but the present species cannot be 

 confounded with either of these. 



Plate XX. Fig. 13, Natural size. 



Locality. Darlington District. 



Museum, College of Charleston. 



The genus Pandora appears for the first time in the Eocene, is found in the overlying 

 formations, and exists in greatest number in the seas of the present period. 



CYCLASIDiE. 

 CYRENA.— Lam. 



CYEEM DBNSATA. — Con. 



Plate Xiv Fig. 14. 



Cyrena densata, Con., Foss. Ter. For., p. 68, pi. 39, fig. 2. 



C. testa crassa, sub-trigona, convexa, cequilaterali, concentrice obsolete-striata; latere buccali 

 rotundato; latere anali sub-truncato; margine palliali arcuata; umbonibus elevatis. 



Description. Shell somewhat triangular, thick, convex, concentrically and obsoletely 

 striated; buccal side rounded; anal side somewhat truncated; pallial margin regularly 

 arcuated. 



The species bears some resemblance to Cyrena Carolinensis of the coast, but differs 

 from it in being less inflated, in outline less orbicular, and by- the prominent beaks, which 

 are narrower and less erected than in the recent species. 



