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PALEONTOLOGY OF NEW YORK. 
SPHENOTUS, n. g. 
Sphenotus truncatus. 
plate lxv, pigs, i, 4 - 6 . 
Cypricardites truncatus, Conrad. Jour. Acad. Nat. Sci., Phila., vol. viii, pi. 12, fig-. 17, p. 244. 1842. 
Sanguinolites truncatus (Conrad), Hall. Prelim. Notice Lamellibrancliiata, 2, p. 42. 1870. 
“ “ “ “ Pal. N. Y., vol. v, pt. 1. Plates and Explanations: PI. 65, figs. 
1-6. 1883. 
Shell small, trapezoidal; length twice the height; basal margin nearly straight, 
slightly constricted anterior to the middle. Posterior extremity obliquely 
truncate. Cardinal line straight. Anterior end narrow, rounded. 
Valves depressed-convex at the posterior end, moderately convex below, 
becoming gibbous above the middle. 
Beaks at about the anterior fourth or fifth, small, appressed, incurved, 
rising but little above the hinge-line. Umbonal slope angular, extending to 
the post-inferior extremity. Post-cardinal slope flat, or concave, with an 
obscure fold along the middle. A shallow cincture extends from the beak 
obliquely to the base of the shell. 
Surface marked by fine concentric striae, which are fasciculate on the 
anterior portion and umbonal region, producing low undulations ; also marked 
by very fine radiating striae. Interior unknown. 
Three specimens measure respectively 10, 15 and 18 mm. in length, and 5, 
7 and 9 mm. in height. 
This species differs from S. arcceformis in its straighter basal margin, less 
pointed and less obliquely truncate posterior end and in its smaller size. 
Formation and localities. In the shales of the Hamilton group, at Summit and 
Bear’s gulf, Schoharie county, and on the shore of Skaneateles lake, N. Y. 
