Crassatella Mississippiensis

Ac

Crassatella Mississippiensis, Conrad, Proc. Ac. Nat. Sc. vol 3 p 291

Ovate-trigonal, inequilateral, thick and ponderous; surface coarsely striated; summits flattened, sulcated; umbo plano-convex, with numerous sulci, obsolete behind the umbonial slope, which is angulated and subcarinated above; posterior extremity truncated, direct; basal margin slightly contracted anterior to the umbonial slope; inner margin crenulated. L. 3.0

Eocene Tertiary
Vicksburg Miss.