LAME L LIB RANCHI A TA . 
467 
The surface of the anterior and middle portions of the shell is minutely pus- 
tulose and marked by extremely fine radiating strim, which extend obliquely 
backward from the beak. 
Three specimens measure respectively 43, 50 and 52 mm. in length, and 
17, 19 and 22 mm. in height. 
This species is distinguished by its straight cardinal line and the gentle curva¬ 
ture of the basal margin, and by the fact that the umbonal ridge extends to the 
posterior extremity at about the middle of its height, while in the other species 
it extends to the post-inferior extremity. 
Formation and localities. In the Hamilton group at Pratt’s falls, Onondaga 
county, and in Schoharie county, N. Y. 
ClMITARIA RECURVA. 
PLATE LXXVII, FIGS. 9-14, 16. 
Cypricardites recurva, Conrad. Jour. Acad. Nat. Sci., Phila., vol. viii, p. 24f>, pi. 18, tig. IS. 1842. 
Plerinea punct.ulata, Conrad. Geol. Snrv. N. Y., Ann. Rep., p. 1 LG. 1838. 
Cypricardites recurva, Vanuxem. Geol. Surv. N. Y., Rep. Third Dist., pp. 152-3. 1842. 
Chnitaria recurva (Conrad), Hall. Prelim. Notice Lamellibranchiata, 2, p. 68. 1870. 
In part “ “ “ “ Pal. N. Y., vol. v, pt. 1. Plates and Explanations: PI. 77, figs. 9—1G. 
1883. 
Shell large, falcate; length nearly three times the height. Basal margin 
broadly curving with a slight sinuosity toward the anterior end. Posterior 
extremity broadly rounded or sub-truncate. Cardinal line long, concave. 
Anterior end short, broadly rounded, obliquely truncated above by the lunule. 
Escutcheon large. Lunule long and abruptly limited. 
Valves depressed-convex in the basal and posterior portions, becoming 
gibbous above and in the’ umbonal region. 
Beaks sub-anterior, prominent, appressed and closely incurved. Umbonal 
slope obtusely angular, curving downward and becoming obsolescent before 
reaching the post-inferior extremity. Post-cardinal slope broad, flattened or 
slightly concave. Cincture an undefined flattening or depression, extending 
from the beak obliquely backward to the base, and producing a slight sinuos¬ 
ity in the margin. 
