matter in Ohio Bh«l Sl„0,* m 



Art. XIX. — A Source of the bituminous matter in the Devonian 

 and Sub- Carboniferous Black Shales of Ohio; by Edward 

 Orton, Columbus, Ohio. 



There are three strata of black shale in the Devonian and 

 sub-Carboniferous series of Ohio, viz: the Huron and the 

 Cleveland shales of Newberry and the Waverly Black shale of 

 Andrews. The latter name, I have followed Meek in replac- 

 ing by the designation Berea shale. It constitutes the base of 

 the Cuyahoga shale of Newberry. The first of these strata is 

 unquestionably Devonian in age, and the last is referred with- 

 out dispute to the sub-Carboniferous series. To the same 

 division is referred the Cleveland shale by Newberry, on 

 account of the presence in it of fishes of sub-Carboniferous type. 

 In northeastern Ohio the Cleveland shale is separated from 

 the underlying Huron shale by the Erie shale of Newberry, a 

 mass of green and blue shale which ranges from nothing to 

 1,000 feet in thickness. Dr. Newberry showed, a number of 

 years since, that the Erie shale thinned out as it was followed 

 westward from the northeastern counties, and disappeared 

 altogether in Huron county, letting the black Cleveland shale 

 down, by overlap, upon the underlying Huron shale, which is 

 also b i. I 1 ' }ia\ sine* show! that it is this compound stra- 

 tum, the Cleveland (Erie), Huron shale, that constitutes the 

 great black shale of Ohio, that extends from Lake Erie south- 

 ward to the Ohio Eiver and beyond. In central and southern 

 Ohio, at least, it seems impracticable to divide it, and to refer 

 one portion to the Devonian and another to the sub-Carbonif- 

 erous, from the lack of characteristic fossils or stratigraphieal 

 marks in the formation. The average thickness of the com- 

 pound formation through the State is probably not less than 

 300 feet. 



The Berea shale, which directly overlies the Berea Grit, 

 ranges from 15 to 50 feet in thic tied bom 



the great black shale by an interval of 100 to 150 feet, the 

 interval being occupied by the Bedford shale and the Berea 

 Grit of Newberry. In northern Ohio the upper bonndarj of 

 the Berea shale is not well defined. In central and southern 

 Ohio, it is sharp and distinct. 



These several beds of shale contain, as their color indicates, 

 a notable quantity of organic matter. The proportion ranges, 

 according to published analyses, from 8 to 21 per cent, the 

 higher proportion having been found in some phases of the 

 Berea shale. 



The sources of this bituminous matter have not as yet been 

 made apparent. The presence of conodonts and fish remains 



