108 
PALAEONTOLOGY OF NEW YORK. 
In all the specimens observed the dorsum is carinate and striate, while the 
dorso-lateral part of the body-volution, as it descends into the sinus, is often 
smooth or obscurely striate. It is possible that in some conditions of preser¬ 
vation, the carinate dorsum may not be so distinct from the body of the 
volution as in those specimens examined; and this feature may be represented 
as “ a very acute periphery.” At the present time, I prefer to adopt the name 
given by Mr. Conrad to the risk of increasing the synonymy. 
In specimens where the strife are continuous over the surface, this fossil 
bears much resemblance to the B. Chasteli, Leveille, having, a precisely 
similar dorsal elevation, but with much finer surface striae. Where the 
transverse striae are interrupted, or become obscure on the sides of the 
volution, it resembles the B. Vcrneuili of d’Orbigny, except in the presence of 
the dorsal elevation. 
Formation and locality. In the shales of the Hamilton group, on the eastern 
shore of Cayuga lake, N. Y. 
Bellerophon natator. 
PLATE XXIV, FIG. 1. 
Bellerophon expansus. Geology of N. Y. Surv. "Fourth Geolog. Dist., pp. 243-4, fig. 3.' 1S43. 
Not Bellerophon expansus, Sowerby. 
Bhragmostoma natator, Hall. Descriptions of New Species of Fossils, etc., p. 32. 1861. 
“ “ “ Fifteenth Rep. N. Y. State Cab. Nat. Hist., p. 60. 1862. 
“ “ “ Illustrations of Devonian Fossils, pi. 23. 1876. 
Not Phragmostoma natator. Explanations of plate 6, figs. 12-14. Fifteenth Rep. State Cab. Nat. Hist.* 
Shell with the inner volutions comparatively small/and apparently closely 
incurved; the outer volution abruptly expanded towards the aperture, 
which is broadly oval, with the transverse much greater than the longi¬ 
tudinal diameter; the peristome broadly and deeply sinuate in front. 
The sides of the shell are strongly undulated or wrinkled. 
Surface marked by fine concentric strife of growth, which bend abruptly 
backward on approaching the dorsum. 
* These figures are illustrations of Phragmostoma cymbula of the age of the Hudson river group, and 
were referred by mistake to P. natator. 
