80 
PALEONTOLOGY OF NEW YORK. 
quadrilineota of Sandberger, but it differs in the compound peripheral hand, in 
which feature it may be compared to P. subclathrata of Sowerby, which is 
somewhat similar in form, hut has several cariniform revolving striae above 
and below the peripheral band. In the comparative elevation of the spire this 
species is intermediate between the two mentioned. It may also be compared 
with the P. conica of Phillips, Avliich has a tricarinate peripheral band, but no 
carina above or below. 
Formation and localities. In shales of the Hamilton group, near Fultonham, 
Schoharie county, the shores of Cayuga, Seneca and Canandaigua lakes, and 
in the Genesee valley near Geneseo, N. Y. 
Pleurotomaria adjutor, n. sp. 
PLATE XXI, FIG. 16. 
Pleurotomaria trilix, Hail. Illustrations of Devonian Fossils: Gasteropoda, pi. 20. 1876. 
Shell depressed-turbinate, obliquely ovoid-conical, wider than high. Yolutions 
convex, about four or five in the entire shell, gradually increasing in size 
in the upper ones, and more rapidly below, the last one much expanded 
laterally and ventricose; lower side convex, becoming more gibbous 
towards the aperture, and somewhat abruptly depressed into the umbilical 
cavity. Aperture transverse, broadly oval. 
Surface marked by a simple, strong, revolving carina on the upper side of the 
volution, a little nearer to the periphery than to the suture, and another 
similar, but a little less strongly marked carina, at an equal distance 
below the peripheral band, which is bicarinate, with a narrow depressed 
space between, crossed by the slightly curving concentric strife; strong, 
distinct, and somewhat distant transverse strife rise from a thickened 
band just without the suture, and extend in an almost vertical direction 
to the carina, passing which they bend backwards somewhat abruptly to 
the margin of the peripheral band, which is crossed by finer strife, and 
below which the coarser strife resume their character, and, passing the 
lower carina, are almost as conspicuous on the lower side of the volution 
