458 PALEONTOLOGY OF NEW YORK. 



nal slope distinctly angular, slightly arching, and extending to the post-infe- 

 rior extremity. Post-cardinal slope narrow, gently concave. 



Surface marked by fine concentric striae, which are preserved in the cast, 

 and are fasciculate on some portions of the shell. 



The specimen described has a length of 53 mm. and a height of 55 mm. 



This species is distinguished by its large size, great elevation, broad rounded 

 base, narrow cardinal slope, and sub-erect umbonal ridge. In these characters 

 it differs very distinctly from any of the other species known in the rocks of 

 New York. 



Fortnation and locality. In the Chemung group, one mile west of Guilford, 

 Chenango county, N. Y. 



SCHIZODUS CUNEUS. 



PLATE LXXV, FIGS. 29, 30 ?. 



In part Cytherodon {Schizodtcs) cuiieus, Hall. Pal. N. Y., vol. v, pt. 1. Plates and Explanations: P). 75, 



figs. 27-30. 1883. 



Shell small, ovate-cuneate ; length about one-fourth greater than the height ; 

 basal margin broadly curved. Post-inferior extremity angular. Posterior 

 margin very obliquely truncate. Cardinal line equal to about half the length 

 of the shell. Anterior end short, contracted just below the beak and regu- 

 larly rounded below. 



Valves gently convex below, becoming gibbous in the middle. 



Beaks at about the anterior fourth, moderately prominent. Umbonal 

 slope angular, defined, extending to the post-inferior extremity. 



Surface marked by fine fasciculate concentric striae, the remains of which 

 are still preserved in the cast. 



The anterior muscular impression is comparatively large and strongly 

 limited on the posterior side. The impression of the strong cardinal tooth 

 is preserved beneath the beak. 



Two specimens measure respectively 20 and 22 mm. in length, and 15 and 

 15 mm. in height. 



