GASTEROPODA. 
77 
more than half an inch. Two symmetrical specimens measured have the 
proportions of width and height as 5 to 7 and 9 to 13. The casts of the 
interior, when well preserved, show a narrow, slightly elevated band on the 
periphery of the outer volution. 
Formation and localities. In the soft calcareous shales of the Hamilton 
group, on the shores of Skaneateles, Seneca, Cayuga and Canandaigua lakes; 
at Bellona, Yates county; at York, Moscow and other places in the western 
counties, and more rarely on the shore of Lake Erie. It occurs in the 
condition of casts in Madison and Otsego counties, and in the same form in 
Maryland and Virginia. 
Pleurotomaria capillaria. 
PLATE XX, FIGS. 18-21. 
Pleurotomaria capillaria, Conrad. Jour. Acad. Nat. Sci. Phil., vol. 8, p. 271, pi. 16, fig-. 11. 1842. 
“ “ “ Hall: Descriptions of New Species of Fossils, etc., p. 17. 1861. 
“ “ “ “ Fifteenth Rep. N. Y. State Cab. Nat. Hist., p. 45, pi. 5, fig. 2. 1862 . 
“ “ “ “ Illustrations of Devonian Fossils: Gasteropoda, pi. 20. 1876. 
The following is the description of this species, as given by Mr. Conrad, 
loc. cit.: 
“ Turreted, volutions slightly angulated below the middle, with spiral cari- 
nated lines; the second and third lines from the suture, on the upper part of 
the volutions, more distant from each other than from the adjoining strife; 
upper part of the volutions very obliquely rectilinear. Surface with equal 
sharp lines which cross the volutions obliquely.” 
The fossil which I have identified with Mr. Conrad’s species possesses the 
following characters: 
Shell turreted, one-fourth to one-third higher than wide. Volutions four or 
more, somewhat rapidly increasing in size, the last one ventricose, 
subangulated above by two or three prominent revolving carinfe, and 
rounded on the lower side. Aperture subrhomboidal. 
Surface on the upper side of the volutions marked by two or three 
revolving carinfe, with finer intermediate ones or strong strife, and all 
are crenulated by finer distant transverse strife; lower side of volutions 
