MARYLAND GEOLOGICAL SUKVEY 263 



Height, 15 mm. ; diameter, 30 mm. 



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



Collections. — Maryland Geological Survey, Johns Hopkins University, 

 Philadelphia Academy of Natural Sciences, Wagner Free Institute of 

 Science, Cornell University. 



Calliostoma marylandicum n. sp. 



Plate LXI, Figs. 15a, 15b. 



Description. — Shell small, depressed, umbilicate ; spire much depressed, 



domed ; body whorl large ; mouth round ; top of the whorl with six sharply 



incised revolving lines; lines of growth faint; body whorl with faint 



oblique streaks of color. 



Height, 7 mm.; diameter, 5.4 mm. 



Occurrence. — Calvert Formation. Plum Point. 



Collection. — U. S. National Museum. 



Calliostoma calvertanum n. sp. 

 Plate LXI, Figs. 16a, 16b, 16c. 



Description. — Shell small, much depressed, umbilicate; spire conic; 

 periphery with a concave groove above, below which the whorl is wound ; 

 earlier whorls with three revolving ribs which gradually become obsolete ; 

 surface of later whorls smooth, highly polished, marked only by very fine 

 closely-set lines of growth and still finer revolving stria ; base slightly con- 

 vex ; umbilicus large and deep ; umbilical periphery angular ; mouth sul> 

 quadrate. 



Height, 3.5 mm.; diameter, 6 mm. 



Occurrence. — Calvert Formation. Plum Point. 



Collections. — Maryland Geological Survey, Johns Hopkins University. 



Family UMBONIID.E. 



Genus TEINOSTOMA Adams. 



Teinostoma nanum (Lea). 



Plate LXII, Figs, la, lb, Ic, 2a, 2b, 2c. 



Eotella nana Lea, 1833, Contrib. to Geology, p. 214, pi. vi, fig. 225. 



Botella umbilicata H. C. Lea, 1843, New Fossil Shells from the Tertiary of Virginia 



Abst. p. 10. 

 Rotella umbilicata H. C. Lea, 1845, Trans. Amer. Philos. Soc, vol. ix, p. 2(54, pi. 



xxxvi, fig. 80. 



