IS© 
PALAEONTOLOGY OF NEW-YORK. 
The interior of both valves is strongly pustulose, but the muscular markings 
are not defined in the specimens examined. 
In many of the smaller specimens from the Corniferous limestone, there are 
but from twelve to sixteen strong rounded striae, and tfie ventral valve is very 
gibbous (figure 2, Plate 20). In some specimens the cardinal extemities are con¬ 
siderably produced, but this is not a common feature. The species is sometimes 
associated with C. lineata and C. lepida in the same fragment of stone. In the 
Hamilton group, it has been found more* frequently in the harder semicalcareous 
beds. 
The great variation in convexity, number of striae and general aspect, leads 
me to suspect that the following ( C. deflecta) may perhaps be only another phase 
of the same species. 
Geological formation and localities. In the Corniferous limestone of Manchester, 
Ontario county; at Williamsville and Clarence-hollow; and on the Indian 
Reservation to the southeast of Buffalo in Erie county. These localities furnish 
the gibbous forms with strong striae designated C. laticosta. In the Marcellus 
shale, the species is found at Avon in Livingston county, at Crooked creek near 
Darien in Genesee county, and at Alden in Erie county. It occurs in the Hamil¬ 
ton group at Pratt’s falls, and in other localities in Onondaga and Madison 
counties. 
Chonetes deflecta. 
PLATE XXL 
Chonetes deflecta : Hall in Tenth Report on State Cabinet, p. 149. 1857. 
Chonetes gibbosa : Id. Ibid. p. 145. 1847. 
Shell semielliptical; length and width as four to five or eight to nine, 
but rarely proportionally wider. 
Ventral valve extremely gibbous, regularly arched, the greatest eleva¬ 
tion being about the middle of the length; abruptly depressed towards 
the cardinal angles, which are flattened, with the extremities deflected 
to the ventral side. The umbo is a little elevated above the cardinal 
margin, and the minute apex (in perfect specimens) projects a little 
over the area. 
Dorsal valve deeply concave, but not equalling the convexity of the 
ventral valve. 
Area of the ventral valve narrow, with the exterior margin declining in 
a gentle curve to the extremities : the triangular foramen is partially 
