THE WESTERN AND NEW YORK FORMATIONS. 267 



Notes explanatory of a Section from Cleveland, Ohio, 

 TO the Mississippi River, in a southwest Direction; 

 WITH Remarks upon the Identity of the Western 

 Formations with those of New York. By James 

 Hall. 



In the American Journal of Science and Arts for January 1842, 

 I gave a hasty sketch of some observations made during an ex- 

 cursion through the Western States, as far as the Mississippi river. 

 This tour was undertaken, as I then stated, with a view to ti'ace 

 the gi'oups of rocks known in New York, westward, and if pos- 

 sible to identify them with those to which different names had 

 been given by the Western Geologists. No extended attempt of 

 this kind had been made from actual examination and compari- 

 son, so far as I know, and the inferences from published reports, 

 and the occurrence of certain fossils, had not proved satisfactory. 

 The formations of the West, as described, did not correspond 

 with the order as established in New York ; and the discrepancy 

 could only be accounted for by supposing the thinning out of 

 some important formations, or the occurrence of others not there 

 existing. 



Mi\ Vanuxem, whose observations were publislied in Silli- 

 man's Journal in 1829, was the first person who pointed out the 

 similarity of some of the Western formations with those of New 

 York. He identified the lower rocks of Ohio, Kentucky, and 

 Tennessee, with the Trenton limestone, from the occurrence of 

 many of the same genera and species of fossils common to both. 

 Before starting on this tour, I was referred by him to some local- 

 ities which were important in settling the questions of identity or 

 difference, and I am indebted to the same source for information 

 of the existence of the Birdseye and Trenton limestones at 

 Frankfort in Kentucky. 



Having, in New York, adopted certain subdivisions or groups 

 of the strata, which are strictly in the order of natui'e, it became 

 a matter of much interest, to ascertain how far the same subdivi- 

 sions would hold good in distant localities, where there was 

 evidently great change in lithological characters. In employing 



