20 PLEIOCENE FOSSILS. 



Jam. OSTRACISE. 



OSTREA.— Linn. 

 OSTREA VIRGINIANA.— Gmel. 



Plate A 7 ., Figs. 6, 7, 8 and 9. 

 Ostrea Virginica, Gmel., Sys. 3336, JSTo. 113. Foss. Shells, Tertiary For. Vol. 1, p. 28, Tab. 14, Fig. 2. 



0. testa irregular^ olilonga, ovata, crassa; valva inferiors, radiatim plicata, rugosa vel 

 radiatim undulata ; valva superiore, subcomplanata lamellosa, vel radiatim plicata. 



Description. Shell irregular, ovate oblong, thick ; lower valve radiately plicate rugose, 

 or radiately undulating ; superior valve somewhat flat ; lamellar or plicate. 



It is difficult to find a characteristic for this exceedingly variable fossil, and in this 

 respect it resembles its living representatives. Sometimes the valves are barely marked by 

 radiating, almost smooth and narrow ridges, and again both valves are strongly plicated, 

 and roughened by coarse raised plates. The beaks are generally pointed, and the ligamental 

 fossa long. For the most part the fossils are thicker and more strongly plaited than the 

 recent forms of this species. 



The specimen figured in Plate V., Fig. 7, is related by the markings on the upper valve, 

 to 0. sculpturata, Con. Fig. 5 is a very marked variety, known along the coast of South 

 Carolina as the Raccoon Oyster. It is very long, narrow and coarsely lamellar. Full grown 

 individuals are often seven inches in length, and not more than an inch wide. 



This variety has only been found fossil in the Waccamaw, above Conwayboro'. Notwith- 

 standing the great abundance of oysters in all the estuaries along the coast, beds of oyster 

 shells are of rare occurrence in our middle or upper tertiary strata, nor have we seen a 

 single such bed in South Carolina; on the contrary, 0. Vieginiana is rather a rare fossil. 



Plate V., Fig. 6, resembles that of the recent species known along the coast of /South Carolina as the 

 Raccoon oyster. 

 " 7. Upper view of variety related to 0. Sculpturata, Con. 

 " 8. Lower view of same. 

 " 9. Side view. 



Locality. Smith's, Goose Creek; Waccamaw. 



Museum, College of Charleston. 



