152 SYSTEMATIC PALEONTOLOGY 



more prominent near and below the suture ; labrum margin rounded ; 

 body whorl with obsolete revolving lines." Conrad, 1862, 



The subsutural band is deeply concave and the shoulder is very promi- 

 nent and strongly nodular. The sinus is deep and gently rounded and 

 is in the center of the subsutural band. The body whorl is as long as 

 the spire, and the beak is attenuated and somewhat twisted. 



Length, 16 mm.; diameter, 5 mm. 



Occurrence. — St Mary's Formation. St. Mary's River. 



Colleciions. — Maryland Geological Survey, Johns Hopkins University. 



Surcula rotifera Conrad. 

 Plate XLI, Fig. 16. 



Pleurotoma rotifera Conrad, 1830, Jour. Acad. Nat. Sci. Phila., vol. vi, 1st ser., p. 



224, pL ix, fig. 9. 

 Surcula rotifera Conrad, lSfi3, Proc. Acad. Nat. Sci. Phila., vol. xiv, p. .561. 

 Surcula rotifera Meek, 1864, Miocene Check List, Smith. Misc. Coll. (183), p. 31. 



Description. — "Shell subfusiform; spire with an elevated crenulated 

 carina on each whorl; two approximate carinse near the middle of the 

 large volution; sinus profound." Conrad, 1830. 



The " elevated crenulated carina " occupies the middle of each whorl 

 of the spire, and the shoulder of the body whorl. Below this, on the 

 body whorl, are about ten elevated revolving lines, not carinated. The 

 spire is coiled upon the second and most prominent of these. The sinus 

 is deep and gently rounded and is situated half way between the shoul- 

 der and the suture. 



Length, 25 mm.; diameter, 9 mm (8 whorls). 



Occurrence. — St. Mary's Formation. St. j\Iary's River. Calvert 

 Formation. Plum Point. 



Collections. — Maryland Geological Survey, Johns Hopkins University, 

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



Surcula mariana n. sp. 



Plate XLI, Fig. 17. 



Description. — Shell six-whorled; whorls strongly convex and deeply 

 constricted at the suture, each with three or four smooth revolving 



