240 GEOLOGY OF OHIO. 



Devonian and Carboniferous ages, and may be enumerated as follows, in 

 descending order : 



Approximate 

 thickness. 



Cuyahoga shale and sandstone 50 feet. 



Berea grit o0 



Bedford shale 2 



Cleveland shale •••• 50 



Erie shale 30 



Huron shale 200 



Olentangy shale 30 



Upper Corniferous (Tully and Hamilton limestones) 35 " , 



Lower Corniferous (Corniferous and Onondaga limestones) 75 " 



Total approximate thickness 525 



Of these the first five belong to the Carboniferous, the remainder to the 

 Devonian.* 



The Cuyahoga Shale and Sandstone. — This shale further north, and 

 especially at Cleveland, has a very great development, reaching there the 

 thickness of one hundred and fifty feet. In Crawford county it has not 

 been certainly identified in outcrop, but most probably underlies the fiat 

 land in the eastern part of Vernon, Jackson, and Polk townships. It is 

 met with in Morrow county, where the arenaceous character becomes so 

 strong that it is often quarried for building. Further south it is proba- 

 bly the equivalent of the " Logan sandstone," one of the members of the 

 Waverly group. 



The Berea Grit. — This is the most important member of the Waverly 

 group. Its line of outcrop is marked by a series of quarries which crosses 

 the eastern tier of townships, the most important of which are located 

 in Jackson and Polk townships. Beginning in Auburn township, the 

 most northerly outcrop of the Berea within Crawford county is in S. W. £, 

 section 28, where it is found along a little creek on Samuel Hilborn's 

 land, and at the highway bridge. It also occurs near DeKalb, in Vernon 

 township, on Mr. James Coruther's land. Slight exposures occur also 

 S. W. i, section 19, along a little creek on land of Barnet Cole and Adam 

 Freeze. It may also be seen on the land of James Campbell and Jacob 

 Myers. In section 36 (Sandusky), it is exposed in a ravine on the farms 

 of David Wirtz and Fred. Beech. In Jackson township, N. E. \, sec- 

 tion 1, is James Morrow's quarry. 



Section at James Mokeow's Quarry, Section 1, Jackson Township. 



Ft. In. 



No. 1. Thin-bedded sandstone 8 



No. 2. Heavy-bedded sandstone 27 



No. 3. Shale (Bedford and Cleveland), not well seen 33 6 



Total thickness 68 6 



* Dr. Newberry. 



