MARYLAND GEOLOGICAI, SURVEY 173 



Family VOLUTID/E. 



Genus SCAPHELLA Swainson. 

 SCAPHELLA SOLTTARIA (Coiirad). 



Plate XLIV, Fig. 7. 



Vohita solitaria Conrad, 1830, Jour. Acad. Nat. Sci. Phila., vol. vi, 1st ser., p. 218, 



pi. ix, tig. 7. 

 Voluta solitaria Conrad, 1863, Proc. Acad. Nat. Sci. Pliila., vol. xiv, p. 563. 

 Voluta solitaria Meek, 1864, Miocene Check List, Smith. Misc. Coll. (183), p. 19. 

 ScapJiella wUtarhi Dall, 1890, Trans. Wagner Free Inst. Sci., vol. iii, pt. i, p. 80. 

 Scaphella solitaria Harris, 1893, Amer. Jour. Sci., ser. iii, vol. xlv, p. 24. 



Description. — " Shell ovate oblong, smooth ; spire with the whorls con- 

 cave above, and straight at the sides, having the angles tiiberciilated; 

 aperture dilated at the base; cohimella four plaited. 



" The large whorl is obsoletely striated at the base, and the plaits on 

 the columella are oblique and subequal." Conrad, 1830. 



There are a few important characteristics not noted in the original 

 description. Dr. Dall states that the color pattern is the same as on 

 the recent S. junonia Hwass, which is the type of the genus. The 

 nucleus is very obtuse with no elevated point and its second whorl is 

 marked by four deeply im])ressed, regularly spaced, revolving grooves 

 which die out as the shoulder becomes tuberculate. 



The specimens from Plum Point have a much more angular and more 

 strongly tuberculate shoulder, with a deeper concavity above it, than 

 those from the younger beds, and the body whorl is more strongly 

 striate at the base. One specimen from Plum Point has faint revolv- 

 ing strife above the shoulder of the body whorl. The specimens from 

 St. Mary's River frequently have the shoulder entirely free from tuber- 

 cles and not at all angular: this is especially true of the later whorls. 



Length, 43 mm.; diameter, 23 mm. 



Occurrence. — St. jMary^'s Formation'. St. Mary's River. Calvert 

 Formation. Plum Point. 



Collections. — Maryland Geological Survey, Johns Hopkins University, 

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



