398 SYSTEMATIC PALEONTOLOGY 



JVucula limatula Conrad, 1845, Fossils of the Medial Tertiary, pp. 57, 58, pi. xxx, 



fig. 4. 

 Nucula limatula Tuomey and Holmes, 1856, Pleioceue Fossils of South Carolina, 



p. 52, pi. xvii, figs. 13-15 (not of Say). 

 Toldia Icevis Conrad, 1863, Proc. Acad. Nat. Sci. Phila., vol. xiv, p. 581. 

 Toldia Icevis Meek, 1864, Miocene Check List, Smith. Misc. Coll. (183), p. 5. 

 Toldia Icevis Dall, 1898, Trans. Wagner Free Inst. Sci., vol. iii, pt. iv, p. 596. 



Description. — " Transversely elongate-subovate,. rostrated, nearly 

 smooth. 



" Shell compressed, thin, fragile, polished, smooth, slightly wrinkled 

 toward the base; beaks nearly central, hardly prominent beyond the hinge 

 margin, rounded, approximate; series of teeth siibrectilinear, a little 

 arcuated behind; teeth prominent; hinge margin exteriorly both before 

 and behind the beaks rather abruptly compressed; posterior margin 

 rounded ; anterior margin somewhat rostrated, the anterior hinge margin 

 rectilinear, very little reflected at tip ; inner margin simple." Say, 1824. 



This species has often been confused wWh. the Pleistocene and Recent 

 Y. limatula, of which it is doubtless the ancestor. " It differs from the 

 latter by its proportionally larger chondrophores, smaller and more nu- 

 merous teeth, somewhat more pointed posterior end and less compressed 

 escutcheon." Dall. 



Casts from three miles north of Plum Point reach a very large size, 

 being 5 cm. in length and 2 cm. in height. Specimens from other places 

 are a half to a third these dimensions. 



Occurrence. — St. Mary's Formation. Cove Point, St. Mary's River, 

 Langley's Bluff. Choptaxk Formation. Jones Wharf, Sand Hill. 

 Calvert Formation. Church Hill, Fairhaven, Parker Creek, 3 miles 

 north of Plum Point, Lyon's Creek, White's Landing. 



Collections. — Maryland Geological Survey, Johns Hopkins University, 

 U. S. National Museum. 



Family NUCULID/E. 



Genus NUCULA Lamarck. 



ISTucula proxima Say. 

 Plate CVIII, Figs. 5, 6. 



Nucula obliqua Say, 1820, Amer. Jour. Sci., vol. ii, p. 40; not of Lamarck, 1819. 

 Nucula proxima Say, 1822, Jour. Acad. Nat. Sci. Phila., vol. ii, 1st ser., p. 270 



