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PALAEONTOLOGY OF NEW YORK. 
BELLEROPHON, Montfort. 
SPECIES OF THE UPPER HELDERBERG GROUP. 
Bellerophon curvilineatus. 
PLATE XXII, FIRS. 1-6. 
Bellerophon curvilineatus, Conrad. Jour. Acad. Nat. Sci. Phil., vol. 8, p. 269, pi. 10, f. 7. 1842. 
“ “ “ Hall: Descriptions of New Species of Fossils, etc., p. 27. 1861. 
“ “ “ “ Fifteenth Rep. N. Y. State Cab. Nat. Hist., p. 55, pi. 6, figs. 8, 9. 1862. 
“ “ “ “ Illustrations of Devonian Fossils: Gasteropoda, pi. 25, figs. 25-30. ’76. 
Shell discoidal. Volutions four or five, compressed and sharply carinated on 
the back, each one embracing about half the width of the preceding one, 
the last scarcely more ventricose than the preceding, and bending almost 
rectangularly at the umbilical edge. Aperture triangular, acute at the 
anterior margin, which is deeply sinuate; the curvature of the peristome 
from the umbilical side receding about one quarter of a volution to the 
dorsal line. The inner margins of all the volutions are exposed in the 
cavity of the umbilicus. 
Surface marked by fine strise of growth, which follow the curvature of the 
peristome, making a retral curve of about one quarter of a volution; 
often slightly fasciculate, but sometimes the strise are in regular fascicles 
of about six or seven finer ones, with a fine sharply elevated one separating 
them. The dorsum is sharply carinate. 
The casts are angular on the back, showing a wide umbilicus, revealing the 
inner volutions. This species has somewhat the form and proportions of the 
B. dubia of d’Orbigny; but the umbilicus is proportionally larger, and the 
outer volution less rapidly widening towards the aperture. The following is 
the author’s description of B. curvilineatus: 
“ Discoid ; volutions exposed; back sharply carinate; surface with oblique 
arched strim.” 
This species, cited by Mr. Conrad as occurring in the Onondaga limestone, is 
more abundant in the Schoharie grit; though in this rock it rarely preserves the 
shell. In size, the specimens of this species vary from about one quarter of an 
