GEOLOGICAL SCALE AND STRUCTURE. 31 



lid. The Ctiyahoga Shale 



It is impossible to retain for this great division of the Waverly the 

 limits assigned to it by Newberry when he gave it its name. He made 

 it fill the entire interval between the Berea grit and the Coal Measure 

 conglomerate, and according to present knowledge, at least three distinct 

 elements are to be found in every full and normal section of this interval. 

 One of them, viz., the Berea shale, has been cut off from the foot of the 

 column. Another, and a much more conspicuous division, has been taken 

 off of the top of the column, viz., the L,ogan group. But there still remain 

 one hundred and fifty to four hundred feet of a perfectly distinct, homo- 

 geneous and most persistent formation that deserves a name as much as 

 the Berea grit itself, or any other stratum in the Ohio scale, and for 

 which no more suitable name could be found than that which it already 

 bears, viz., the Cuyahoga shale. 



It consists of light-colored, argillaceous shales, which are often re- 

 placed with single courses of fine-grained sandstone, blue in color, and in 

 southern Ohio weathering to a brownish-yellow. As a constant charac- 

 teristic there are found through the shales nodules of impure iron ore, 

 generally flat in form, concretionary in origin, and often having white cal- 

 careous centers. 



By good rights the shale should suffer one more reduction at its lower 

 extremity. Everywhere through the state there is found, directly above 

 the Berea shale, or at a short remove from it, a number of courses of fine- 

 grained stone. These courses are sometimes separated from each other 

 by beds of shale, or they may be compacted into a single stratum. The 

 individual courses also vary greatly in thickness and in color and general 

 characters. Throughout southern Ohio, and particularly in Ross, Pike 

 and Scioto counties, the stratum yields freestone. It is best known from 

 its outcrops on the Ohio River at Buena Vista, where it has long been 

 very extensively worked for Cincinnati and other river markets. The 

 Buena Vista stone, at its best, is one of the finest building stones of the 

 country. The same horizon yields excellent stone near Portsmouth, 

 Lucasville and Waverly. At the latter point it is known as the Waverly 

 brown stone. 



Northward, through the state, stone of more or less value is found in 

 the bottom courses of the Cuyahoga, but in Trumbull county, near War- 

 ren, the horizon acquires extreme importance as the source of the finest 

 natural flagging that is to be found in our markets. 



It would have bee a well if the thirty or forty feet containing these 

 courses had been cut off from the Cuyahoga shale, in which case the divi- 

 sion thus formed would have been well named the Buena Vista stone ; 

 but inasmuch as the series does not absolutely require the change, it is 

 left unmodified. The Sharpsville sandstone of White ( Second Penna. 

 Survey, Q. 4 ) belongs to this horizon and is the proper equivalent of the 

 Buena Vista stone. 



