GASTEROPODA OF THE LOWER GREEN MARLS. 91 



the middle and narrowed below; aperture very large, elongate, two-thirds 

 the length of the shell and seinielliptical, straightened on the inner side and 

 rounded on the outer margin; columella strong, marked by two strong 

 oblique folds near the middle of its length; surface unknown, but on the 

 inner volution of the type and on a smaller specimen in the collection Am. 

 Mus. Nat. Hist., N. Y. City, there are a few distant vertical plications, faintly 

 indicated, but which do not extend below the most ventricose part of the 

 whorl. 



This species, like most of the others, is known only from the internal 

 casts, so that the external characters of the shell are not known. Its form 

 will readily distinguish it from any other shell in the marls of the State. It 

 more nearly resembles Volutomorpha Abhotti Gabb from the middle beds 

 than any other, but may be very readily distinguished by its greater 

 ventricosity and by the volutions being most ventricose near the upper part 

 rather than being evenly curved as in that one. The body volution is also 

 more rapidly contracted in the lower part, the spire shorter, and the whorl 

 very much more rapidly increasing in size. 



Formation and locality : The type is from the brown layers of the Lower 

 Green Sands in "Burlington County, New Jersey," and belongs to the col- 

 lection Acad. Nat. Sci., Phila. A second specimen is from Mullica Hill, 

 New Jersey, and is in the Am. Mus. Nat.' Hist. 



VOLUTODERMA OVATA, n. Sp. 



Plate X, Figs. 3, 4. 



Shell below a medium size, subovate in general outline, being large 

 above the middle of the length and attenuated toward the base; spire 

 short; its apical angle nearly 90° on the internal casts, with strong, rounded 

 volutions and very deep, strongly marked sutures; body volution propor- 

 tionally large, forming nearly the bulk of the cast; greatest diameter a 

 little below the shoulder and rapidly diminishing below; aperture large, 

 nearly straight on the inner margin, strongly rounded above on the outer 

 margin, and gently curved along the lower two-thirds of the length; colu- 

 mella proportionally strong, leaving a large cavity on removal, as seen in 

 the cast; marked by two strong, very obhque plications or folds above the 



