150 SYSTEMATIC PALEONTOLOGY 



of growth; beneath the suture whorls obtusely subcarinated, distinct re- 

 volving lines over the ribbed portion, minute and obsolete above it; 

 suture profound; body whorl and beak striated; beak slightly curved." 

 Conrad, 1862. 



The sinus is in the middle of the subsutural concavity. It is very 

 deep and distinct but gently rounded. 



Length, 32 mm. ; diameter, 12 mm. 



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

 mation. Plum Point. 



Collections. — Maryland Geological Survey, Johns Hopkins University, 

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



SURCULA MARYLANDICA Courad. 



Plate XLI, Fig. 13. 



Pleurotoma Marijlandica Conrad, 1841, Proc. Acad. Nat. Sci. Phila., vol. i, p. 30. 

 Pleurotoma Marylandica Conrad, 18-13, Jour. Acad. Nat. Sci. Phila., vol. viii, 1st. 



ser., p. 185. 

 Fleurotomo. Marijlandica Conrad, 1843, Proc. Nat. Inst., Bull, ii, p. 182. 

 Surcula Marylandica Conrad, 186.S, Proc. Acad. Nat. Sci. Phila., vol. xiv, p. 561. 

 Surcula marylandica Meek, 1864, Miocene Check List, Smith. Misc. Coll. (183), 



p. 31. 

 ? Pleurotoma marylayidica Meyer, 1888, Proc. Acad. Nat. Sci. Phila., vol. xl, p. 170. 

 Pleurotoma marylandica Harris, 1893, Amer. -Jour. Sci., ser. iii, vol. xlv, p. 24. 



Description. — " Fusiform, with spiral wrinkled lines ; upper half of 

 whorls of spire concave, the lower convex, and with oblique ribs. Length 

 2^ inches." Conrad, 1841. 



The spire and beak are attenuate, and the beak straight. The whorls 

 are covered with distinct revolving spirals. The siphonal notch is above 

 the shoulder, making the ribs oblique where they cross the shoulder. 

 This species is distinguished by its oblique ribs, faint sculpture, and 

 long, straight beak. 



Length, 50 mm.; diameter, 16 mm. 



Occurrence. — Calvert Formation. Plum Point. 



Collections. — Maryland Geological Survey, Johns Hopkins University, 

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

 Cornell University. 



