7 
_ Notes on American Geology. 251 
- inhis report as occurring in exactly the same order, whether they 
are traced from the uppermost, (the anthracite coal formation,) 
- southward, towards tide water, or northward, to the end of the 
section in New York; and in no instance, in either half of the 
line, was evidence obearyed of any want of conformity between 
adjacent strata. Such a section, where it crossed the Kittatinny 
Valley, would display the calciferous sandrock of Eaton, under- 
lying conformably the metalliferous limerock of the same author, 
and this in turn underlying conformably the graywacke of the 
Hudson, while near its northern. extremity it would exhibit the 
calciferous sandrock.in conformable position below the limestone 
of Trenton Falls, and this again in similar relation, passing under 
‘the foundation of the Salmon river. That such is the state of 
things, Professor Rogers appears to feel satisfied from a careful 
study of the country around both the southern and northern ends 
of this supposed section. He therefore regards the so named 
graywacke of the Hudson as the same with the gray sandstone 
formation of Oswego county. . He considers the argument based 
on the want of identity in the fossils as inconclusive, until it 
shall appear that a large number of species from each formation 
have been compared, and this because he places more confi- 
dence in conclusions drawn from following the rocks themselves 
over wide areas of country, (the only mode by which their true 
order of superposition can be first established, ) than in inferences 
based upon the organic remains, the true significance of which 
can never be known until large groups of species are studied, 
and until the order of superposition“of the strata, the very mat- 
ter under discussion, shall have been previously settled a By inde- 
eee ze 
