NIAGARA GROUP. 
Ill 
shale, and is one of the ordinary fossils of the group, being found in all localities. In speci¬ 
mens from the limestone, the annulations are stronger and more acute. 
Locality —Lockport, Rochester, Sweden, Clarendon, in shale and limestone. 
Several other species of Orthocerae occur in this group, among which are forms closely 
resembling, if not identical with O. virgatum (Silurian Researches, pi. 9, f. 4), or 0. undu- 
latum (Mineral Conchology, t. 59), and O. imbricatum (His. Pet. Suec. p. 29, t. ix, f. 9; 
and Silurian Researches, pi. 9, f. 2). 
2. Conularia quadrisulcata? (Miller, M. C. t. 260, f. 3 and 4 ; His. Pet. Suec. p. 30, 
t. x, f. 5; Silurian Researches, p. 626, pi. 12, f. 22). — Conical; crossed by obliquely 
transverse furrows and ridges, which are not always equal. The ridges are finely and beau¬ 
tifully crenulated, and the furrows crossed by grooves which are a continuation of the spaces 
between the crenulations of the ridges. Shell compressed; in shale, much expanded, and 
larger than specimens usually figured. It is ordinarily found in fragments of a much smaller 
size. 
Since the character of the surface is so similar in this and other species, it is not improbable 
that several have been confounded under this name. 
Locality —Lockport, Rochester. 
CRINOIDEA. 
The species of this family appear to have been more abundant in this group than in any 
other in the State ; and there are probably as many species, well identified, from the Niagara 
shale, as from all the other rocks of the New-York System. An explanation of their structure 
will be found in another place; nothing more being intended in these illustrations, then to 
present the usual appearance of the fossil. 
41. 
s 
1, 2. Caryocrinus ornatus. 3. Cyathocriniles pyriformia. 
