GASTEROPODA OF THE LOWER GREEN MARLS. 91 
the middle and narrowed below; aperture very large, elongate, two-thirds 
the length of the shell and semielliptical, 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 veritricose 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 Abbotti 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, 0. 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 oblique plications or folds above the 
