86 
PALAEONTOLOGY OF NEW YORK. 
Crenipecten micropterus. 
PLATE IX, FIG. 23. 
Crenipecten micropterus. Hall. Pal. N. Y., vol. v, pt. 1. Plates and Explanations: PI. 9, figs. 2, 3. 
Jan., 1883. 
Shell small, longitudinally and obliquely sub-elliptical; length somewhat 
greater than the height; margins regularly rounded, produced behind and 
extending in nearly a direct line to the beak. 
Right valve depressed-convex. Left valve unknown. 
Hinge-line short, straight, anterior; length about one-third the height of 
the valve. 
Beak low, obtuse. Umbonal region not strongly defined, subtending an 
obtuse angle. 
Ears very small, nearly equal, bounded by shallow sulci. Byssal sinus 
not distinct. 
Surface marked by numerous low, rounded radii, with wider interspaces 
and smaller intermediate radii; crossed by fine concentric lines of growth, 
which are stronger and crowded on the ears, forming their only surface 
marking. 
Interior unknown. Ligamental area obscurely crenulate. 
The specimen described has a length of 18 mm., width 16 mm., hinge¬ 
line 5 mm. 
This species resembles in form C. crenulatus, but differs in the radii, and in 
the proportionally much shorter hinge-line. The surface markings are similar 
to C. liratus, but it is different in its proportions of length and height. 
Formation and locality. In the shales of the Chemung group at Philipsburg, 
Alleghany county, N. Y. 
