GASTEROPODA OF THE EOCENE MARLS. 233 
above; base convex-depressed, slightly indented on thé margin; umbilicus 
profound.” The specimen which he used I suppose to be one of these now 
before me, but it is a very trifle larger than his figure, while the umbilical 
portion has been restored, as will be seen by the comparison of the two 
figures of his plate. The specimen is marked with ink on the base, which 
fact helps in its identification. I do not, however, understand the meaning 
of his statement that the base is “ slightly indented on the suabmargin,” as no 
such feature is visible on any specimen examined. This one differs from 
the other associated forms in being more depressed, which may be partially 
the result of compression in the rock, but it differs principally in the form 
of the volution, being flattened on the top, and sloping on the outer mar- 
gin, while the other, L. gigantea, is sloping from suture to suture without 
any flattening on the top, and it has a much more elevated spire and truly 
conical form. 
Formation and locality: In the upper layer of the Upper Green Marls, 
at Shark River, New Jersey, and is usually represented in collections by 
detached fragments of the volutions. Collections at Rutgers College and 
Am. Mus. Nat. Hist. 
LEPTOMARIA GIGANTEA, 0. sp. 
Plate xxxvil, Figs. 1 and 2. 
Shell very large, conical in form, with an apical angle of 75° to 80°; 
volutions probably five or six in number, nearly as high as wide, with the 
surface obliquely flattened between the sutures in the direction of the spire, 
or very slightly convex in the upper half, but without any flattening on the 
top below the suture; base broadly and deeply concave, with a large per- 
spective umbilicus, in which all the volutions would be shown in a perfect 
specimen, and in the cast with a scarcely perceptible suture line between 
them. From the outer basal angle, which is somewhat acute, the base is 
very gently convex for a short distance within the margin, whence it curves 
rapidly into the umbilical cavity; aperture large, rather higher than wide, 
obliquely rhombic or trapezoidal in outline, with the basal line and inne 
margin forming a continuous but increasing curve from the outer basal 
angle to the upper inner angle; surface of the shell unknown, but that of the 
