OLD RED SANDSTONE. 
279 
The whole series has not yet been sufficiently investigated, to know if it admits of the same 
subdivisions here as in England; yet it is very true, that to a certain extent, it possesses the 
same lithological characters, and contains some at least of the same organic remains. 
The existence of this rock, although so well known in England and some other parts of 
Europe, was for a long time considered enigmatical in this country; and it is only since the 
commencement of this survey, that it has been satisfactorily identified by its fossils. 
In 1824, Prof. Eaton first suggested the existence of the Old Red sandstone on the Catskill 
mountains,* though he appears to have overlooked this fact in his subsequent arrangements. 
Some years afterwards, R. C. Taylor, Esq., in a report upon the Coal region about Bloss- 
burgh, Pa., mentions the Old Red sandstone as existing there, and between that point and the 
State line on the north. There was no other notice of its existence in this part of the country, 
till the publication of the Geological Reports for 1840, when it was fully identified by its fossils. 
To the west of the Genesee, I have only detected this rock in loose masses upon the 
surface, though it is possible that it may occur at some of the elevated points, which, from 
being entirely covered by forests, have escaped observation. Farther west, however, where 
good opportunities for examination exist, it is not found; and it thus becomes evident, that in 
this direction the rock disappears not far from the Genesee, in Allegany county. From this 
fact it will be perceived, that there is a very rapid diminution in thickness from the Catskill 
mountains to the point of its disappearance. This shows a condition of the primeval ocean 
greatly different from its state during the deposition of the preceding groups, where a series, 
with a thickness less than this one in its greatest development, extends nearly or quite as far 
as the Mississippi, more than one thousand miles beyond the termination of the Old Red sand¬ 
stone. This change in condition was evidently, in part, a diminution in the transporting power 
of the oceanic currents, which had previously carried forward similar materials over the broad 
extent before described. Other changes may have supervened, but we can scarcely conceive 
of any other which would produce similar phenomena. 
The materials forming the Old Red Sandstone are, to a great extent, as easily transported 
as those of the rocks below; still their extent is limited in New-York, and westward as far 
as Ohio this rock is not represented at all. Still farther west the rocks of the Chemung 
group are succeeded by sandstones and thin beds of limestone, wholly unlike the red and 
green sandstones and sandy shales of New-York; and they contain, at the same time, a 
different assemblage of organic remains. Other changes, too, have supervened at the west, 
of which we have no evidence in New-York; and the most striking is the occurrence of an 
important mass of limestone below the conglomerate, which is the great supporting rock of 
the Carboniferous system. 
In order to institute a comparison between the rocks of this period in New-York and those 
at the west, the following woodcut, illustrating the relative position of rocks in Indiana, will 
serve to give the reader all necessary data. 
Si ~ 
* Canal Rocks, p. 92„ 
