248 SYSTEMATIC PALEONTOLOGY 



Height, 20 mm. ; diameter, 35 mm. 



Occurrence. — Choptank Formation. Greensboro. Calvert Forma- 

 tion. Church Hill, 3 miles west of Centerville, Reed's, Plum Point, 

 Chesapeake Beach, 3 miles south of Chesapeake Beach, White's Landing. 



Collections. — Maryland Geological Survey, Johns Hopkins University, 

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

 nell University. 



Calyptr^a centralis (Conrad). 

 Plate LIX, Figs. 2a, 2b, 2c. 



Infundiiulum centralis Conrad, 1841, Amer. Jour. Sci., voL xli, p. 348. 

 Infundihulum concentricum H. C. Lea, 1843, New Fossil Shells from the Tertiary of 



Virginia, Abst., p. 6. 

 Infundihulum centralis Conrad, 1845, Fossils of the Medial Tertiary, No. 3, p. 80, 



pi. xlv, fig. 5. 

 Calyptrcea (Infundibulum) concentricum H. C. Lea, 184.5, Trans. Amer. Philos. Soc, 



vol. ix, p. 249, pi. XXXV, fig. 39. 

 Trochita centralis Tuomey and Holmes, 1856, Pleiocene Fossils of South Carolina, 



p. 109, pi, XXV, fig. S. 

 Trochita centralis Emmons, 1858, Rept. N. Car. Geol. Survey, p. 276, tig. 139. 

 Trochita centralis Conrad, 1863, Proc. Acad. Nat. Sci. Phila., vol. xiv, p. 568. 

 Trochita concentrica Conrad, 1863, Proc. Acad. Nat. Sci. Phila., vol. xiv, p. 568. 

 Trochita centralis Meek, 1864, Miocene Check List, Smith. Misc. Coll. (183), p. 15. 

 Trochita concentrica Meek, 1864, Miocene Check List, Smith. Misc. Coll. (183), p. 15. 

 Calyptrcea centralis Dall, 1892, Trans. Wagner Free Inst. Sci., vol. iii, pt. ii, p. 353. 



Description. — " Obtusely ovate, with fine concentric irregular lines ; 

 apex central." Conrad, 1841. 



" Suborbicular or obtusely ovate, tumid above, marked with transverse 

 wrinkles ; apex medial, minutely spiral, prominent, acute." Conrad, 1845. 



This species is distinguished by the entire absence of spines and the 

 presence of the irregular spiral lines or wrinkles, and also by a peculiar 

 reflected lip on the septum, under which is an umbilicus on the columella. 



Height, 10 mm.; diameter, 18 mm. 



Occurrence. — St. Mary's Formation. St. Mary's Eiver. 



Collections. — Maryland Geological Survey, Johns Hopkins University, 

 U. S. National Museum, Cornell University. 



CaLYPTR^A GREENSBOROiiNSIS n. Sp. 



Plate LIX, Figs. 3a, 3b. 

 Description. — Shell small, depressed, globose, very eccentric, three- 

 whorled; sutures indistinct, especially on the later whorls; whorls con- 



