Gasteropoda oE' the eocene maeLs, 217 



Genus SURCULA (H. & A.) Adams. 



SURCULA PEROBESA, n. Sp. 



Plate XXXIII, 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. ai3. 



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 



