188 GEOLOGY OF OHIO. 



Bedford Shale. — Below the Berea sandstone is a bed of shale forty to 

 sixty feet in thickness, which is sometimes blue or banded in color, but 

 more generally red. This red shale is conspicuously shown in the val- 

 ley of the Vermilion^ and is exposed at many places in this section of 

 the State immediately underlying the Berea sandstone ; it may, therefore, 

 serve as an important guide to those who are seeking for the excellent 

 quarry stone furnished by that formation. Neither the Berea sandstone 

 nor the red shale have in Erie county furnished any fossils ; but at Elyria, 

 Lorain county, and at Berea and Bedford, Cuyahoga county, a large num- 

 ber of remains of mollusks and fishes have been taken from these strata. 



Cleveland Shale. — Under the red shale in the banks of the Vermilion 

 occurs a black, bituminous shale, here sixty or more feet in thickness. 

 This is a constant member of the Waverly or Lower Carboniferous 

 group, and forms the base of that series. It is unusually well exposed 

 in the vicinity of Cleveland, and I have therefore called it, for conveni- 

 ence sake, "the Cleveland shale." In its lithological characters this 

 shale is hardly to be distinguished from the great black shale (the 

 Huron shale) which is a member of the Devonian system, and which 

 here lies only a little below. Further east, however, they are separated 

 by an interval of several hundred feet, and the fossils which they con- 

 tain are widely different. In the Cleveland shale are bones, scales, and 

 spines of fishes of small size and of Carboniferous types. In the Huron 

 shale, on the contrary, we find the remains of fishes of enormous size, of 

 most peculiar structure, and such as clearly belong to the Old Red Sand- 

 stone fauna so fully described by Hugh Miller. 



Erie Shale. — The lake shore from the Pennsylvania line to Erie county 

 is, for the most part, formed by a series of green and blue shales, -which 

 represent the Chemung and Portage rocks of New York, and belong to 

 the Devonian formation. These shales thin out rapidly westward, and 

 cease to be recognizable beyond the point under consideration. In the 

 valley of the Cuyahoga they are exposed to the depth of one hundred 

 and forty feet, and have there yielded the most characteristic fossils of 

 the Chemung. 



The upper layers of the Huron shale are interstratified with the lower 

 ones of the Erie in the north-eastern portion of the State, as we learn by 

 borings made at Cleveland and further east. Some traces of this inter- 

 locking may be seen at Monroeville, where the well sunk at the railroad 

 station cuts some blue as well as black shales. South of this point, how- 

 ever, the Erie shale has not been recognized, and it probably reaches but 

 a little way back from the lake shore. 



Huron Shale. — This is a name we have given to the great mass of black 



