282 SYSTEMATIC PALEONTOLOGY 



St. Mary's Eiver. Choptank Fokmation, Governor Kun, 2 miles 

 south of Governor Emi, Flag Pond, Jones Wharf, Turner, Pawpaw 

 Pomt, Dover Bridge, Peach Blossom Creek, Trappe Landing, Cordova. 

 Calvert Formation. Fairhaven, Chesapeake Beach, 3 miles south of 

 Chesapeake Beach, Plum Point, Lyon's Creek, White's Landing, Tru- 

 man's Wharf, Wye Mills, 3 miles west of Centerville, Church Hill. 



Collections. — Maryland Geological Survey, Johns Hopkins University, 

 U. S. National Museum. 



CORBULA CUNEATA Say. 



Plate LXVII, Figs. 15, 16, 17, 18, 19. 



Corbula cuneata Say, 1834, Jour. Acad. Nat. Sci. Phila., voL iv, 1st ser., p. 1.52, 



pL xiii, fig. 3. 

 Corbula intequale Conrad, 1838, Fossils of tbe Medial Tertiary, p. 6, pi. iii, tig. 3, 



(left hand one), (diagn. and remarks excluded.) 

 Corbula cuneata Meek, 1864, Miocene Check List, Smith. Misc. Coll. (183), p. 12. 

 Corbula (Cuneocorbula) cuneata Dall, 1898, Trans. Wagner Free Inst. Sci., vol. iii, 



pt. iv, p. 854. 



Description. — " Shell transversely ovate-trigonal, acutely angulated or 

 somewhat rostrated hefore, and depressed on the anterior slope, which 

 is separated from the disk by a subacute line: surface of both valves 

 similarly striate with equal, elevated, equidistant lines, forming grooves 

 between them; the striae on the smaller valve are rather more distant: 

 umbones not prominent." Say, 1824. 



It may be distinguished from C. inccqualis by having striae that are 

 much finer and more close set, equal, and equidistant than in C. 

 incequalis. It is also much less common. When found at all it is more 

 commonly at the Jones Wharf horizon. 



Length, 12 mm.; height, 7.5 mm.; diameter, 2.5 mm. 



Occurrence. — Choptank Formation. Governor Run, 2 miles south 

 of Governor Run, Flag Pond, Jones AVharf, Pawpaw Point, Turner, 

 Trappe Landing, Greensboro, Cordova. Calvert Cormation. Plum 

 Point. 



Collections. — Maryland Geological Survey, Johns Hopkins University, 

 U. S. iSTational Museum. 



