GASTEROPODA OP THE EOCENE MARLS. 233 



above; base convex-depressed, slightly indented on the 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 submargin," 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. 



Lbptomaria gigantea, n. sp. 

 Plate XXXVII, 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 innei 

 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 



