PLEIOGENE FOSSILS. 65 



Description. Shell obliquely ovate, thin, somewhat ventricose, radiately, very finely 

 striated; margins finely crenulated within. 



This fossil resembles some forms of C. serratum, living on the coast of Florida; but it 

 is less ventricose, especially towards the pallial margin. The anal side is also much less 

 curved. 



Both valves of this shell are often found in juxtaposition, and the polish of the surface 

 scarcely destroyed. 



Plate XIX. Fig. 3, Interior of right and exterior of left valve, natural size. 



Locality. Waccamaw and Darlington District. 



Museum,, College of Charleston. 



The genus Cardium is found in the upper Silurian rocks, and represented in greatest 

 number of species in the actual or present period. 



CAIMTIM. 



CARDITA.— BruguierE, 



CAKDITA AEATA. 

 Plate XIX. Figs. 4 and 5. 



Cypricardia arata. Con., Foss. Shells, Ter. For., p. 20, pi. 5, fig. 1. 

 Carditamera arata, Con., Foss, Ter. For., p, 12, pi. 6, fig 2. 



C. testa ovato-oblonga; costis transversim-radiantibus, rotundatis nodulosis; latere buccali 

 brevissimo; latere anali truncato. 



Description. Shell ovately oblong; ribs transversely radiated, rounded, noduloes; 

 buccal side very short; anal truncated. 



