84 
PALEONTOLOGY OF NEW YORK. 
The specimens are casts of the interior preserved in coarse sandstone; the 
surface markings are consequently obliterated. 
Formation and locality. In a coarse sandstone of the Chemung group near 
Olean, Alleghany county, N. Y. 
Crenipecten obsoletus. 
PLATE IX, FIGS. 19, 21. 
Lima? obsoleta, Hall. Geolog. Surv. N. Y. : Rep. Fourth Dist., p. 265. 1843. 
Crtnlpecten obsoletus, Hall. Pal. N. Y., vol. v, pt. 1. Plates and Explanations: PI. 9, tigs. 19, 21. 
Jan., 1888. 
Shell small, obliquely sub-ovate, length nearly equal to the height; margins 
regularly curved, becoming produced on the post-basal side, and somewhat 
rectilinear on the posterior side. 
Yalves very similar. Right valve depressed-convex. Left valve regularly 
convex. 
Hinge-line straight, a little more than one-half the length of the shell. 
Beak obtuse, more prominent on the left valve; situated in the centre of 
the hinge. Umbonal region well defined in the left valve; depressed and 
undefined in the right valve. 
Ears small, triangular, sub-equal, defined by shallow sulci; margins gently 
concave,; extremities obtuse. Posterior ear a little the larger. Byssal sinus 
not conspicuous. 
Test thin, marked by fine, closely arranged, concentric striae, which are 
crowded and stronger on the ears. No radiating striae have been discovered. 
Ligamental area narrow, marked by a row of minute cartilage-pits. 
A left valve measures 18 mm. in length, 20 mm. in height, hinge-line 10 
mm. A similar right valve is 16 mm. in length, 17 mm. in height, hinge¬ 
line 8.5 mm. 
This species bears some resemblance to C. cremdatus, but is more elongate- 
ovate ; less oblique, with the height somewhat greater than length. 
Formation and locality. In shales of the Chemung group at Philipsburg, 
Alleghany county, N. Y. 
