

96 PLEIOCENE FOSSILS. 



Description. Shell triangular; longitudinally striated, with equal, parallel, regular 

 impressed, but indistinct lines; buccal margin obliquely truncated, cordate, suture sub- 

 convex ; anal margin nearly rectilinear, suture indented ; pallial margin a little prominent, 

 beyond a regular curve, near the middle; interior edge crenate. 



This is an abundant recent species upon the sea shores of the South, and is found also 

 fossil in great quantities in the Post Pleiocene beds. We have only an insignificant 

 specimen to figure, but many casts are to be seen in the marl of Goose Creek. 



Plate XXIII. Fig. 6, Fossil, natural size. 



Locality. Sumter District; Smith's, Goose Creek.' 



Museum, College of Charleston. 



MACTRA.— Lam. 



The genus Mactra commenced its existence in the seas of the Jurassic period. 



MACTRA OBLONGATA. — Say. 



Plate X1III. Pig. 1. 



Mactra oblongata, Say, Jour. Acad. Nat. Sci., Vol. 2, p. 310. 



M. testa transversa oblongo-ovali, leviter rugata; plicis duabis ad marginem buccalem 

 ab apice radiantibus. 



Description. Shell transverse oblong-oval, very slightly wrinkled; buccal margin 

 with two distinct lines or folds extending from apex. 



The specimen from which our figure is -taken was found in the marl beds of the Pee 

 Dee, and compared with recent shells of the same species so abundant on the sea shore of 

 Waccamaw, is remarkably large. At first we were disposed to consider it a distinct 

 species, but upon careful examination and comparison can discover no difference whatever, 

 except size. 



Plate XXIII. Fig. 7, Natural size. 



Locality. Pee Dee. Museum, College of Charleston. 



