166 SYSTEMATIC PALEONTOLOGY 



The only specimen known from Maryland is young and badly broken. 

 Length, 12 mm. ; diameter, 8 mm. 



Occurrence. — St. Mart's Formation. St. Mary's Elver. 

 Collection. — Wagner Free Institute of Science. 



Cancellaria (Trigonostoma) biplicifera Conrad. 

 Plate XLIII, Fig. 10. 



Cancellaria biplicifera Conrad, 1841, Proc. Acad. Nat. Sci. Phila., voL i, p. 31. 

 Cancellaria biplicifera Conrad, 1842, Jour. Acad. Nat. Sci. Phila., vol. viii, 1st ser., 



p. 187. 

 ? Cancellaria antiqua Wagner, 1848, plate iii, tig. 3 (plates privately distribiited). 

 ? Cancellaria antiqua Bronn, 1848, Hand. Gesch. Nat., Index Pal., pt. i, p. 208. 

 ? Cancellaria antiqua Bronn, 1849, Hand. Gesch. Nat., Index Pal., pt. ii, p. 46.5. 

 Cancellaria (Trigonostoma) biplicifera Conrad, 1863, Proc. Acad. Nat. Sci. Phila., vol. 



xiv, p. .567. 

 Cancellaria (Trigonostoma) biplicifera Meek, 1864, Miocene Check List, Smith. Misc. 



Coll. (183), p. 17. 

 Cancellaria biplicifera Conrad, 1866, Amer. Jour. Conch., vol. ii, p. 67, pi. iii, tig. 4. 

 ? Cancellaria antiqua Dall, 1898, Trans. Wagner Free Inst. Sci., vol. v, pt. ii, p. 11, 



pi. ill, tig. 3. 



Description. — " Turrited, with thick longitudinal ribs, and spiral 

 rather distant impressed lines; on the body whirl an occasional ["inter- 

 mediate," 1841] fine line; space below the suture widely and deeply 

 channelled ; shoulder coronated ; umbilicus small ; columella concave, and 

 with two plaits. Length 1^ inch." Conrad, 1842. 



" Subovate, with rather thick, prominent ribs, and revolving, broad 

 stride, and an intermediate fine line; ribs slightly convex; summits of 

 the whorls widely and deeply channelled; shoulder coronated; umbilicus 

 small; columella concave, biplicate." Conrad, 1866. 



This is the largest of the Miocene species of Cancellaria and one of 

 the rarest. 



There is little doubt that the form figured by Wagner but never 

 described is of this species. The rest of his Miocene fossils were from 

 Jones Wharf, which is the locality where this species occurs most 

 abundantly and best developed. 



Length, 57 mm.; diameter, 37 mm. 



Occurrence. — Choptank Formation. Jones Wharf. Calvert For- 

 mation. Plum Point. 



Collections. — Maryland Geological Survey, Johns Hopkins University, 

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



