MARYIM.ND GEOLOGICAL SURVEY 167 



Subgenus SVELTIA Jousseaume. 



Cancellaria (Sveltia) patdxentia n. sp. 

 Plate XLIII, Figs. 11a, lib. 



Description. — Shell small, slender, fragile, five-whorled ; whorls deeply 

 constricted at the suture, and strongly and regularly convex ; body whorl 

 with about 30 regular equidistant, raised spiral striae, and with eight or 

 nine strong, longitudinal ribs which are more prominent on the upper 

 part of the whorl, and thus mask the regular convexity of the whorls, 

 giving them the appearance of being flat on top, widest near the top, 

 and sloping gently to the suture below ; whorls of the spire with fifteen 

 to twenty spiral strise; protoconch depressed naticoid in shape, two 

 whorled; mouth ovate; columella with two strong plaits above, and a 

 very weak one below ; labium thick, reflected ; labrum broken in type. 



Length, 10.5 mm.; diameter, 5.5 mm. 



Occurrence. — Choptank Formation". Jones Wharf. 



Collection. — Maryland Geological Survey. 



Cancellaria (Sveltia) calvertensis n. sp. 

 Plate XLIII, Fig. 12. 



Description. — Shell small, five-whorled; whorls of the spire regularly 

 and strongly convex, with eight or nine strong, raised, longitudinal 

 ribs, and about fourteen raised, revolving ribs; sutures deep and dis- 

 tinct; umbilicus small; columella with three plaits increasing in size 

 above; labrum dentate. 



This species resembles C. patuxentia but is more elongate. 



Length, 8.5 mm. ; diameter, 4 mm. 



Occurrence. — Calvert Formation. Plum Point. 



Collection. — TJ. S. National Museum. 



Cantcellaria (Sveltia) sp. 



Description. — Shell small, slender, fragile; columella plaits, two, both 

 very oblique ; no umbilicus ; longitudinal ribs small, distant ; each whorl 

 with eight or ten raised spiral striae, with much broader interspaces. 



This form has a general outline like C. patuxentia, but differs from 

 that species in the characters noted above, and also in being less deeply 



