368 Parallelism of the Paleozoic Deposits 
Portage, Genesee, Tully and Hamilton represent to us the forma- 
tions of the Eifel and of Devonshire; the Marcellus shales are 
the equivalents of those of Wissenbach in the Duchy of Nassau, 
as is proved by their Goniatites, so analogous in form. 
All the groups which we have examined in the Devonian sys- 
tem of America, are not those which are of the most importance, 
since the most part of them disappear in advancing towards the 
west. The most constant beds are the corniferous and Onondaga 
limestones, both of which contain many species of the limestone of 
the Hifel and the Hartz, and should be parallel to its inferior part. 
As to the Oriskany sandstone, as we have said, we are led from 
the character of its Spirifers to consider it as the equivalent of the 
fossiliferous schists on the borders of the Rhine.t 
e comparison which we have made of the different stages 
of the Devonian system in America with that . Europe leads to 
many interesting results. The first is, to remove all species of 
doubt from the classification of the limestones “of the Hifel, the 
Hartz, &c., in showing the place which their equivalents occupy 
in the American series ; the second is, to demonstrate the little im- 
portance of the Ludlow stage, represented solely by some small 
groups, which scarcely extend beyond the limits of the state of 
New York, and perhaps of Pennsylvania ;{ the third, in fine, 1s 
have never seen a Brachiopod of any vom in ge red sandstone, the entire list 
of species so far as known being of some five or six fishes, a single sh ne of the 
form of Modiola, and a ie. owl When we AP Se e to mark the limits be- 
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Fie lass us Productus as » elles ished from Chonetes and Leptena, makes its first ce 
Sbit eoprarance in the Onondaga anid corniferous limestones, continuing through the ami 
and somes groups, becoming even abundant near the close of the latter period. 
r. Vanuxem os compared this rock to the sandstone with Pentamerus - the 
itessin tine of Nassau.) If this is correet, the Oriskany sandstone be ongs 
peg upper Silurian system, the Pentameri of the greifenstein being very similar 
¢ The Ludlo sap is also difficult to be recognized on the continent of Europe. 
ne oa ae ee 
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