34 POST-PLEIOCENE FOSSILS. 



MERCENARIA MORTONI. 

 Plate VI. Pig. 12. 



Venus Mortoni, Conrad, Jour. Acad. Nat. Sci., Vol. 7, p. 251. 

 Venus Mortoni, Conrad, Foss. Ter. Form., p. 8, pi. 5, fig. 1. 

 Venus Mortoni, DeKay, Zool. New-York, Art. Mollusca, p. 219. 

 Mercenaria Mortoni, Adams, Gen. Recent Shells, Vol. 2, p. 419. 



Description-. Shell cordate, inflated, thick and ponderous, with prominent recurved 

 concentric laminae, more elevated on the anterior and posterior margins ; ligament margin 

 arctuate; umbones prominent; lunule large, cordate, defined by a deep groove; posterior 

 extremity slightly emarginate; inner margin regularly crenulated. — Conrad. 



This is the most abundant species of the genus found in the Post-Pleiocene beds, and 

 though not common in the recent state, is still living upon the coast. Mr. Conrad founded 

 the species upon a specimen from Charleston harbor. 



Plate VI. Fig. 12, Right valve, natural size. 

 " 12a, Lunule, natural size. 



Locality. Simmons'. Museum, College of Charleston; Cabinet F. S. H. 



MERCENARIA NOTATA. 

 Plate VI. Fig. 13. 



Venus notata, Say, Jour. Acad. Nat. Sci., Vol. 2, p. 271. 



Venus notata, Gould, Invert. Mass., p. 86, fig. 52. 



Venus notata, DeKay, Zool. New-York, Art. Mollusca, p. 218, pi. 27, fig. 278. 



Venus notata, Ravenel, Cat. Coll. Shells, p. 5. 



Venus notata, L. R. Gibbes, Tuomey's Geol. So. Ca., appendix, p. xxi. 



Mercenaria notata, Adams, Gen. Recent Shells, Vol. 2, p. 419. 



Venus notata, Say's Conch. U. S., (Binney,) p. 49. 



Description. Shell sub-cordate, obtusely rounded before, sub-angulated posteriorly; 

 lateral dorsal margin nearly straight, concentric laminae, more elevated on the posterior and 

 anterior margins, and crossed by radiating stria?, which give the shell a sub-cancellated 

 character; pallial margin beautifully crenulated; color, whitish, with brown and reddish 

 zig-zig marks ; interior margin white, cavity of shell bright purple. 



