MARYLAND GEOLOGICAL SURVEY 203 



The shell is seldom perfect, the spines and the long beak being very 

 easily broken off. The number of varices on the body whorl varies from 

 9 to 12. 



Length, 18 mm.; diameter, 8 mm. 



Occurrence. — St. Mary^s Formation. St. Mary's Eiver. 



Collections. — Maryland Geological Survey, Johns Hopkins University, 

 Philadelphia Academy of Natural Sciences, Cornell University. 



Trophon tetricus var. l^^vis n. var. 

 Plate LI, Fig. 8. 



Fhsux tetricus Conrad (In part). 



Description. — Shell six-whorled; body whorl with 9 to 13 varices; 

 lower part of the body whorl almost or quite smooth, one of the four re- 

 volving ribs of T. tetricus sometimes faintly showing. 



Conrad's description of T. tetricus applies exactly to this variety; but 

 his figures show the character by the lack of which this variety is dis- 

 tinguished, i. e., four raised revolving ribs on the body whorl. 



Length (restored), 27 mm.; diameter, 12 mm. 



Occurrence. — St. Mary''s Foraeation. St. Mary's Eiver, Cove Point. 



Collections. — Maryland Geological Survey, Johns Hopkins University, 

 Cornell University. 



Trophon chesapeakeanus n. sp. 

 Plate LI, Figs. 9, 10. 



Description. — Shell small, fusiform, six-whorled; spire elongate, 

 pyramidal; body whorl much expanded above, constricted below into a 

 long, narrow beak; shoulder of the whorl with about sixteen obtuse elon- 

 gated nodes which die out immediately above the shoulder, leaving a 

 smooth, slightly concave siibsutural constriction; mouth wide, contracted 

 suddenly below into a narrow, somewhat reflexed canal; columella bent 

 near the lower end of the mouth, and somewhat callous at the angle; lines 

 of growth irregular. 



This species is very abundant at the St. Mary's Eiver. At Plum Point 

 a small, very elongated variety occurs. 



Length, 10 mm. ; diameter, 5 mm. 



