280 Thirty-fifth Report on the State Museum. 



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 G. crenulatus, but is more 

 elongate-ovate ; less oblique, with the height somewhat greater than 

 length. 



Formation and locality. In shales of the Chemung group at Philips- 

 burg, Alleghany county, N. Y. 



Crenipecten glaber. 



Lima glaber, Hall. Geolog. Surv. N. Y. : Rep. Fourth Dist., p. 255. 1843. 

 Crenipecten glaber, Hall. Pal. N. Y., vol. v, pt. 1. Plates and Explanations: 

 PI. 9, figs. 20, 22 ? Jan., 1893. 



Shell small, ovate, erect, very slightly oblique; height about one- 

 fifth greater than the length ; pallial margins regularly rounded, 

 more extended on the posterior side. Left valve moderately convex 

 above, and depressed-convex below. Eight valve unknown. Hinge- 

 line straight, length equal to about one-half the length of the valve. 

 Beak acute, erect, somewhat prominent, not elevated above the 

 hinge, Umbonal region well-defined by the sulci, subtending an 

 acute angle. Ears triangular, nearly equal, separated from the body 

 of the shell by shallow sulci; margins straight or slightly concave; 

 posterior ear a little the larger. Byssal sinus not distinct. 



The cast is marked only by fine concentric striae. Interior 

 unknown. The crenulations of the ligamental area are obscure in 

 the specimen. 



The original of this species is 12 mm. in length, 16 mm. in height, 

 and hinge-line 6 mm. 



This specimen is imbedded vertically to the lines of rock bedding, 

 and the proportions of length and height may have been changed. 

 The species is known by its erect form, conspicuous ears and great 

 comparative height. 



Formation and localities. In shales of the Chemung group at 

 Philipsburg and Eockville, Alleghany county, N. Y. 



Crenipecten micropterus. 



Crenipecten micropterus, Hall. Pal. N. Y. vol. v, pt. 1. Plates and Explana- 

 tions : PI. 9, figs. 2, 3. Jan., 1883. 



Shell small, longitudinally and obliquely sub-elliptical ; length some- 

 what greater than the height; margins regularly rounded, produced 

 behind and extending in nearly a direct line to the beak. Eight 



