MARYLAND GEOLOGICAL SURVEY 2G1 



Height, 10 mm.; diameter, 11 mm. 



Occurrence. — Choptank Formation. Jones Wharf, Governor Rim 

 (lower bed), 2 miles south of Governor Run, Cordova. 



Collections. — Maryland Geological Survey, Johns Hopkins University, 

 U. S. National Museum, Wagner Free Institute of Science. 



Calliostoma peralveatum (Conrad). 

 Plate LXI, Fig. 12. 



Trochus peralveatas Conrad, l!S41, Proc. Acad. Nat. Sci. Pliila., vol. i, p. 30. 

 Trochus peralveatas Conrad, 1843, Jour. Acad. Nat. Sci. PhiLi., vol. viii, 1st ser., 



p. 186. 

 TrocJius peralveatux Conrad, 1842, Proc. Nat. Inst., Bull, ii, pp. 183, 183. 

 Trochus peralveatas Conrad, 184(5, Proc. Acad. Nat. Sci. Pliila., vol. iii, p. 31, pi. i, 



fig:. 3.5. 

 Zizyphinus peralveatas Conrad, 1863, Proc. Acad. Nat. Sci. Phila., vol. xiv, p. .569. 

 Zizyphinus peralveatas Meek, 1864, Miocene Check List, Smith. Misc. Coll. (183), 



p. 15. 



Description. — " Volutions 5 or 6, with each a deep groove near the 

 base; space below the suture profoundly and widely channelled; upper 

 margin of whirls acutely carinated; base with 5 profound grooves. 

 Length, If inch.'' Conrad, 1842. 



Length, 13 mm.; diameter, 12 mm. 



Occurrence. — Choptank Formation. Jones Wharf, Calvert Forma- 

 tion. Plum Point. 



Collections. — Maryland Geological Survey, Philadelphia Academy of 

 Natural Sciences, U. S. National Museum, Cornell University. 



Section EUTROCHUS A. Adams. 



Calliostoma humile (Conrad). 

 Plate LXI, Figs. 13a, 13b, 13c. 



Trochus humilis Conrad, 1830, Jour. Acad. Nat. Sci. Phila., vol. vi, 1st ser. p. 319, 



pi. ix, fig. 5. 

 Trochus humilis Conrad, 1842, Proc. Nat. Inst., Bull, ii, p. 187. 

 ? Trochus lens H. C. Lea, 1843, New Fossil Shells from the Tertiary of Virginia, 



Abst., p. 10. 

 ? Trochus lens H. C. Lea, 1845, Trans. Amer. Philos. Soc, vol. ix, p. 365, pi. xxxvii, 



fig. 83. 

 Zizyphinus humilis Conrad, 1863, Proc. Acad. Nat. Sci. Phila., vol. xiv, p. 569. 

 Zizyphinus humilis Meek, 1864, Miocene Check List, Smith. Misc. Coll. (183), p. 15. 

 Calliostoma (EntrocMis) humile Dall, 1893, Trans. Wagner Free Inst. Sci., vol. iii, 



pt. ii, p. 405. (In part.) 



