64 BULLETIN OF THE LABORATORIES 



Scliizodiis tieirai^kensis, -sp. n. 

 (Plate X, Fig. I ) 



■ Shell large, obliquely ovate, produced. Beak j)rominent, not 

 projecting much beyond the hinge. Surface quite convex in the um- 

 bonal region, becoming flattened posteriorly. Lower margin a gentle 

 curve, very oblique to the axis, anterior margin strongly convex, posterior 

 margin a gentle curve meeting the lower line acutely. The post-umbonal 

 region expanded, flat ; anterior umbonal slope rather abrupt. Beaks an- 

 terior; surface marked by fine regular striae. Our single specimen is 

 very remarkable for the strong curvature of the surface below, opposite 

 the beaks and flatness of the posterior ear. This may be due to oblique 

 pressure as the opposite valve is crushed and displaced. Notwith- 

 standing this the ovate form, large size and position serve to distin- 

 guish it. Length 62 mm; height 50 mm; convexity of both valves 

 about 23 mm. Collection of VV. F. Cooper. Highest layers i mile 

 north of Newark. 



Schizodus chcrnun^ensis, vavf aeqiialis, H- 

 (Plate I, Fig. 25.) 



Shell of rather large size, moderately convex; beaks projecting, 

 rather high ; length slightly greather than the height ; form subquad- 

 rate, produced at the lower posterior angle ; lower maigin nearly uni- 

 formly convex, with a slight sinus in front of the posterior angle; pos- 

 terior margin nearly straight and nearly parallel to the longitudinal 

 axis of the shell; anterior margin strongly curved; anterior umbonal 

 ridge rather inconspicuous, post-umbonal ridge prominent, in front of 

 it a rather deep groove extending from the sinus of the margin to- 

 ward the beak: post-umbonal slope rather steep, concave. Surface 

 marked by numerous fine concentric striae and coarser ridges. The 

 right valve is most convex in our specimens. Height 42 mm; length 

 48 mm ; (height 38 mm ; length 42 mm.) 



Freestone of middle Waverly at Granville, and 6 miles northwest. 

 Collected by W. F. Cooper and C. L. Herrick. 



We are convinced that the attempt to specifically discriminate the 



