394 SYSTEMATIC PALEONTOLOGY 



impressed narrow radii; radiating strige minute and obsolete; marginal 

 teeth prominent." Conrad, 1843. 



This is the common species of the Calvert formation. Conrad has 

 caused some confusion l)y listing in 1842, as P. lentiformis, some speci- 

 mens from the Calvert formation at Hance's and Wilkinson's, that must 

 have lieen the then undiscriminated P. parilis. I know of no true 

 P. lentiformis specimens that have been found in Maryland. 



Height, 90 mm.; width, 88 mm.; diameter, 23 mm. 



Occurrence. — St. Mary's Formation. St. Mary's Eiver (Dall). Cal- 

 vert Formation. Chesapeake Beach, 3 miles south of Chesapeake 

 Beach, Plum Point, Truman's Wliarf, Church Hill, Wye Mills, Eeed's, 

 Tilghman's Station, Skipton (Dall). 



The St. Mary's Eiver reference is probably a mistake. No one else 

 has listed it from there. Careful search has failed to find it there, and 

 no specimens fj:om St. Mary's Eiver could be found in the National Mu- 

 seum. 



Collections. — Maryland Geological Survey, Johns Hopkins University, 

 Philadelphia Academy of Natural Sciences, U. S. National Museum, 

 Cornell University. 



Glycymeris subovata (Say). 

 Plate CVII, Figs. 3, 4. 



Peciuncuhts stibovatm Say, 1824, Jour. Acad. Nat. Sci. Phila., voL iv, 1st ser., p. 



140, pi. X, fig. 4. 

 Pecttmculus subovatus Conrad, 18.3;i, Fossil Shells of the Tertiary, p. 17, pi. x, fig. 3. 

 PectuncMhis subovatus Conrad, 1845, Fossils of the Medial Tertiary, p. 62, pi. xxxiv, 



fig. 1. 

 Peciunculus subovatus Emmons, 18.58, Rept. N. Car. Geol. Survey, p. 286, tig. 207. 

 Pectunculus subovatus Conrad, 1S63, Proc. Acad. Nat. Sci. Phila., vol. xiv, p. 581. 

 Pectunculus subovatus Meel<, 1864, Miocene Checlv List, Smith. Misc. Coll. (183), p. 5. 

 Glycimeris subovata Dall, 1898, Trans. Wagner Free Inst. Sci., vol. iii, pt. iv, p. 611. 



Description. — "■ Longitudiually short ovate, with about thirty longi- 

 tudinal impressed acute lines, the intervals a little convex. 



"81iell increasing in width by a slightly curved line from the apex to 

 beyond the middle : lateral curvatures equal : apices separate, small, cen- 

 tral; intervening space with but little obliquity to the plane of the shell, 

 with obsolete angulated lines: teeth forming a regularly and much 



