426 Systematic Paleontology 



Collections. — Maryland Geological Survey, Xew Jersey Geological 

 Survey. 



Outside Distribution. — Matawan Formation. Merchantville clay marl, 

 New Jersey. 



Genus VOLUTOMORPHA Gabb 

 [Proc. Acad. Nat. Sci., Phila., 1876, p. 290] 



Type. — Volutilithes conradi Gabb. 



" Shell elongate, fusiform ; whorls cancellated by longitudinal and 

 revolving ribs. Columella with one very oblique fold, and sometimes one 

 or more smaller secondary folds. In shape this genus is not unlike the two 

 preceding genera, but it differs from them all in having essentially a single 

 large oblique fold. When more than one occurs the secondary folds are 

 smaller than the large primary." — Gabb, 1876. 



Dall, in his elaborate discussion of the Volutidce, 1 has characterized 

 the genus as follows : 



" Volutomorpha is sculptured very much like a worn Rostellites. It 

 differs from Rostellites in being covered with a thin glaze all over, and in 

 having one large plait near the edge of the pillar instead of several 

 subequal plaits. There is sometimes an excavation behind the plait, the 

 posterior edge of which might be mistaken for a second obscure plait. 

 There is a notch or sulcus near or at the suture, very strongly marked 

 at the resting stages of the animal. The nucleus is minute, polished, 

 trochoid. The very young (not larval) shell has all the characters of 

 Piestochilus Meek. The adult shell is thick, the pillar straight; in the 

 mature shell the plait lags behind and is hardly perceptible from the 

 aperture, while in Rostellites it is strong to the end in the species I have 



seen. These shells, like Rostellites, may reach a length of 5 or 6 in 



Volutomorpha may be regarded as a link between Rostellites, Liopeplum 

 and Volutilithes, combining some of the features of each." 



Etymology: Voluta. a spiral shell; txop</>ri, form. 



1 Dall, 1890, Trans. Wagner Free Inst. Sci., Phila., vol. iii, pt. i, p. 73. 



