GASTEROPODA OF THE EOCENE MARBLS. 217 
Genus SURCULA (H. & A.) Adams. 
SURCULA PEROBESA, n. Sp. 
Plate xxx, Figs. 5, 6. 
Shell, as known from internal casts and external imprints, rather above 
a medium size, indicating a length of 2 inches or over and proportionally 
robust, the diameter of the body whorl being equal to considerable more 
than one-third of the entire length; volutions about five in number, dis- 
tinctly angular in the middle, the principal one being concave above the 
angulation and gently convex below that point, and terminating in a short, 
strong, anterior beak; aperture proportionally large; columella strong; vo- 
lutions crossed by numerous oblique folds, twelve of which can be counted 
on the principal one; shell marked by very fine spiral lines, sharply ele- 
vated and with finer lines between them, and also by finer and closer raised, 
almost lamellose lines of growth which cancellate the surface by crossing 
the spiral lines. On the concave upper surface of the principal volution 
the transverse lines present a broad, sweeping, backward curvature, indica- 
ting a broad sinus in the lip of the shell at this point, and below the angu- 
lation are as strongly directed forward over the central part of the volution. 
This shell is of the type of S. tabulata Conrad, from the Claiborne sands, 
but is of much larger size, much more robust, apparently fewer volutions, 
and stronger folds. : 
Formation and locality: In the upper layer of the Upper Green Marls 
at Shark River, New Jersey, and from the collection at Rutgers College; 
some fragments, too poor for illustration, indicate a much greater size than 
those given in the figures. 
Genus SURCULITES Conrad. 
Am. Jour. Conch., vol. 1, p. 213. 
Mr. Conrad proposed this as a subgenus under Surcula Adams, but 
did not characterize it either at the time or subsequently. Mr. Tryon 
describes the genus in his “Structural and Systematic Conchology,” vol. 2, 
p. 183, as follows: “Shell with spire and body volution nearly equal; the 
