458 
PALAEONTOLOGY 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. 
Formation and locality. In the Chemung group, one mile west of Guilford, 
Chenango county, N. Y. 
\ 
SCHIZODUS CUNEUS. 
PLATE LXXV, FIGS. 29, 30 ?. 
In part Ci/therodun ( Schizodus) ctmeus, Hall. Pal. N. Y., vol. v, pt. 1. Plates and Explanations: PI. 75, 
figs. 27-30. 1SS3. 
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. 
Yalves 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. 
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