106 
PALAEONTOLOGY OF NEW YORK. 
specimens observed are more or less distorted by pressure, and the surface- 
markings are but partially preserved. 
Formation and localities. In shales of-the Hamilton group, at York, Livingston 
county, and at Pratt’s Falls in Madison county, N. Y. 
Belleropiion acutilira. 
PLATE*XXV, FIGS. 4-8 * 
Belleropiion acutilira, Hall. Descriptions of New Species of Fossils, etc., p. 28. 1861. 
“ “ “ Fifteenth Rep. N. Y. State Cab. Nat. Hist., p. 56. 1862. 
“ “ “ Illustrations of Devonian Fossils: Gasteropoda, pi. 25. 1S76. 
Shell ovoid or subglobose; the inner volutions discoid, and exposed in the 
rather large umbilicus; the body-volution becoming ventricose and much 
expanded towards the aperture; the ventro-lateral margin angular, and 
sometimes almost carinate from the rectangular bending into the umbilical 
depression ; dorsum obtusely subangular, not carinate ; aperture suborbic- 
ular, a little wider than high; peristome deeply sinuate in front, and the 
posterior margin slightly modified by the preceding volution. 
Surface marked by regular, subequidistant, fine strife, which bending forward 
from the ventral edge of the volution, make a broad curve on the side, 
and turn abruptly backward, making a sharp bend on the dorsal line. 
The dorsum is angular on the upper part of the last volution, but becomes 
regularly convex, with a less abrupt curvature of the striae, upon the more 
expanded part toward the aperture. 
In one specimen of this shell, I find characters corresponding to those given 
by Mr. Conrad to B. brevilineatus. The striae proceeding from the umbilicus 
are Avell marked at first, become obsolete on the side of the volution, and are 
again well marked on the dorsum. This character obtains only on the last 
half of the outer volution; above this the striae are uniform over the whole 
surface. The periphery is obtusely angular, and it does not appear, therefore, 
that this can be identical with the species of Mr. Conrad. At certain stages 
* Figs. 6, 7 and 8 were erroneously referred in the Illustrations of Devonian Fossils (tigs. 19, 20, 21) to 
Cyrtolites mitella. 
