Notes on American Geology. 251 



in his 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 observed of any want of conformity between 

 adjacent strata. Such a section, where it crossed the Kittatinny 

 Valley, would display the calciferous sandrock of Eaton, unde?-- 

 lying confonnahly 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 estabhshed,) than in inferences 

 based upon the organic remains, the tnie significance of w-hich 

 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 by inde- 

 pendent explorations. 



