64 Review of the New York Geological Reports. 
ance, and geological position, with the Onondaga limestone ; but 
we have, as yet, no evidence derived from organic remains. 
Thus it would appear that the Onondaga limestone, though of 
no great thickness, has still a vast range both west and south, 
hundreds of miles beyond the limits of the State of New York. 
At many localities, particularly in the vicinity of Cherry Val- 
ley, the rock in question receives a good polish and forms a hand- 
some marble. 
Hatt suggests, what is highly probelile; that the origin of this 
formation has been a coral reef; where it is thickest, he thinks 
the larger and more hardy species existed; where thinnest, the 
tender corals and Crinoidea flourished in sheltered situations, 
most of which were, by the action of a troubled sea, overturned, 
broken down and scattered over the bed of the primeval ocean. 
The best localities in the state for studying this formation and 
its organic remains, are, near Williamsville, on the farm of Mr. 
Youngs, in the town of Amherst, Erie County ; in Clarence, in 
the same county; at the quarries of Le Roy, Genesee County ; 
in Caledonia, west side of the Genesee, and at Vienna; on the 
road from Fort Plain to Cherry Valley, Otsego County; near Sy- 
racuse, Onondaga County ; and at the falls of Perryville and Caz- 
enovia. On the Helderberg Mountains, in Sharon, Bern and 
Bethlehem, are some of the best localities in the first district for 
collecting specimens of its fossil corals. 
Speaking of its mineral contents, Haun says: “Crystallized 
carbonate of lime, quartz in crystals lining cavities, chalcedony 
and hornstone, with iron pyrites, are the only minerals noticed 
in this rock.”’ Its thickness, the same author informs us, is very 
variable, being from one to twenty, or even forty feet; but Van- 
UXEM Says, it very rarely exceeds ten or fourteen feet. 
Corniferous Limestone of Eaton, (embracing the Seneca lime- 
stone. }—This name was given to the member of the New York 
system now to come under review, by Earon, in consequence of 
the number of flinty and hornstone nodules which it contains. 
These are arranged usually in layers something like flints in chalk, 
and accompany the rock, according to Vanouxem, throughout its 
-entire range. It was not separated by Eaton from the Ononda- 
ga limestone, both being included under this head; now they are 
into two formations, because each is ond to contain 
assemblage of fossils, besides differing in lithological 
