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w | ofs the Older Forge. of the United States. 3 
whole continent, or for the whole globe, I shall merely oferta ~: 
few facts which have fallen under my own observation, and 
this with the hope of calling the attention of other observers to 
-the subject, and aid in deciding the true cause and amount of 
variation in palzozoic characters when examined over wide 
districts. We shall doubtless be led, eventually, to see in all 
these changes the influences of depths of water, distance 
from, or proximity to land, and the influence of the nature E 
of that deposit which formed the bed of the ocean, on which 
the animals lived. Every one of these “causes, and perhaps : 
other minor ones, have influenced the present character and = 
condition of our older fossiliferous deposits. All these circum- 
stances influence the Organic, roductions of our presentocean, 
whatever may be the . te; and we have every proof 
at the same causes operated i in this ancient sea; where, 
although¥lepth and temperature may have been more anit i 
yet these could not have been paramount to all other influ- 
ences: 
These rocks, which are generally k known by the terms “of 
Cambrian, Silurian and Devonian Systems, and to which we e 
have, in New York, applied the term New Yonk Sverrw are 
known. to be of great extent in this country. The rei arche 
"m 
F 
- | very p development, the P range, AE 
paratively co d condition of these rocks in our country, 
| p an opportunity Qe i ee ipa ppdition of- T A 
n 
ib teria Waa adopted to iishal, since at that time the 
divided i into Cambrian, Silurian and Devonian, all of which are p evidently on one men 
in this country; ni also well ascertained that the Camb m 7 
fore known, is, to a g extent, if not gei — of dy We abel t 
. of the Silurian period. — at : 
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