S9© 
PALAEONTOLOGY OP NEW-YORK. 
The larger well-marked individuals have a length of.about one inch; 
and a single specimen, apparently of this species, is nearly two inches 
long. 
In the young or half-grown shells, the valves are moderately convex 
and the beak scarcely incurved, while there is no perceptible truncation 
in front. The flattening of the umbo and umbonal slopes are not con¬ 
stant characters, and we have regularly ovate forms with every part 
limited by curved lines. 
I have received from Dr. G. A. Williams, formerly of Hardy county, Virginia, 
several casts of a species of this genus, which I have referred to this. One of 
those figured upon the plate is proportionally more elongate than the New-York 
forms ; but the shell has been abruptly incurved on the umbonal slopes, flattened 
on the lower part of the ventral valve, and obliquely subtruncate in front. 
Geological formation and localities. This species occurs in the Hamilton group 
on the shores of Seneca and Canandaigua lakes, at Moscow; York and Geneseo in 
Livingston county, and at Pavilion in Genesee county, New-York. 
Cryptonella iphis (n. s.). 
PLATE LXI. 
Shell elongate, subcylindrical. 
Ventral valve more convex than the dorsal, regularly arcuate from beak 
to base, the greatest convexity about the middle of its length, abruptly 
rounded or subtruncate in front. Beak much extended beyond that of 
the opposite valve, and slightly arcuate. 
Dorsal valve somewhat depressed-convex in the middle, and shortly 
' curving to the margins; the upper two-thirds of the length of the 
valve almost equally convex. 
Surface concentrically striated, with a few strong undulations towards 
the front, in the cast. Shell-structure punctate. 
Length one inch; width less than three-fourths of an inch. 
The specimen is almost an entire cast, and is referred to the Genus Crypto¬ 
nella from the elongate form, moderately incurved beak, and character of mus¬ 
cular impressions. The punctate structure of the shell indicates its position among 
the Terebratulidee. 
Geological formation and locality. This shell occurs in the Corniferous lime¬ 
stone, near Cayuga in Canada West. 
