MARYLAND GEOLOGICAL SURVEY 257 



spirals without beads. The periphery is square and sometimes somewhat 

 concave. The base has about six broad spirals and additional smaller 

 ones in the umbilical region which is always imperforate though some- 

 times slightly excavated. 



The species is subject to considerable variation, which consists usually 

 in the loss of the beads on some of the spirals. 



Height, 12 mm, ; diameter, 12 mm. 



Occurrence. — St. Mary's Formation. Cove Point. Choptank For- 

 mation. Jones Wharf, Governor Eun (lower bed), 2 miles south of 

 Governor Eun, Pawpaw Point, Greensboro. Calvert Formation. Plum 

 Point. 



Collections. — Maryland Geological Survey, Johns Hopkins University, 

 U. S. National Museum, Cornell University. 



Calliostoma philanthropus var. 

 Plate LXI, Fig. 4. 



Description. — Earlier whorls with three spirals, the one below the 

 suture coarsely beaded, the medial one with smaller, more closely set 

 beads, the lower over-ridden by several revolving ribs which are each 

 finely beaded; finer imbedded spirals on all except the earliest whorls; 

 periphery of the body whorl with a revolving concavity between the lowest 

 spiral described above and a slightly less prominent one which is hidden 

 on all except the body whorl; base of the body whorl with seven broad 

 spirals. 



Later investigation may show that this is a distinct species, but as a 

 single specimen is all that has been found, its distinctness or relationships 

 cannot now be decided. 



Length, 10 mm. ; diameter, 9 nun. 



Occurrence. — Choptank Formation. Jones Wharf, Pawpaw Point. 



Collection. — Maryland Geological Survey. 



Calliostoma virginicum (Conrad). 

 Plate LXI, Fig. 5. 



Zizyphinus virginicus Conrad, 1875, Rept. N. Car. Geol. Survey, vol. 1, Appendix 



A, p. 33, pL iv, tig. 4. 

 Calliostoma virginicum Dall, 1893, Trans. Wagner Free lust. ScL.vol. iii, pt. ii, p. 



396, pi. xviii, fig. 3. 



17 



