342 
PALAEONTOLOGY OF NEW YORK. 
Formation and locality. In the shales of the Hamilton group, near Norwich, 
Chenango county, N. Y. 
Palaeoneilo brevis. 
PLATE L, FIGS. 24-33. 
Palceonello brevis, Hall. Prelim. Notice Lamellibranchiata, 2, p. 10. 1870. 
“ “ “ Pal. N. Y., vol. v, pt. 1. Plates and Explanations : PI. 50, figs. 24-83. 1883. 
Shell small, ovate, or ovate-sub-triangular; length about one-third greater than 
the height; basal margin gently curving, with a slight constriction toward 
the posterior extremity. Cardinal line arcuate. Anterior end usually short 
and regularly rounded. 
Valves convex below, gibbous in the middle and on the umbonal ridge. 
Beaks usually at about the anterior third or a little posterior thereto, 
prominent, moderately elevated above the hinge-line. Umbonal slope 
marked by a slight flattening of the shell, which produces a gentle constric¬ 
tion in the post-inferior margin. This depression is rarely margined on each 
side by an undefined elevation. 
Surface marked by tine, even, concentric striae ; the casts exhibiting only 
the stronger elevations which give an irregular appearance to the concentric 
striae. Anterior muscular impression very strongly marked. Posterior scar 
large and shallow. Hinge marked by numerous minute crenulations. 
Three specimens of this species measure respectively 21, 20 and 14 mm. 
in length, and 14, 12 and 10 mm. in height. 
This species is allied to P. constrida, but is more gibbous, less curved along 
the basal margin, and the constriction of the posterior end is so slight as to be. 
scarcely detected in most individuals. 
Formation and localities. In some shaly calcareous sandstones of the Chemung 
group, at Franklin, Delaware county; in arenaceous shales, at Philipsburgh, 
Alleghany county, N. Y., and at Lawrenceville, Tioga county, Pa. 
