62 



GEOLOGY OF OHIO. 



of Mr. Read, the base of this ridge is an old moraine of bowlder clay, and 

 such may be its character ; but, as will be seen from the section given 

 below, taken at the point where the Ashtabula and Jamestown Railroad 

 cuts through this ridge, its upper portion is stratified, and it is capped 

 with beach sand. It seems to me more probable that it is a clay terrace, 

 capped with a ridge thrown up by the shore waves. The old swamp, 



, Section of Drift Clays, Ashtabula, 0. 



j. Sandy foam, 1-2 ft. 



a Yellow clay, with fragments 

 of shale, 10 ft. 



3. Blue clay; with fragments of shale 

 and boulders, 14 ft. 



4. Fine sand — local, 0-3 ft. 



5. Coarse gravel — coarsest at bottom, 



10 ft. 



6. Blue clay, with boulders, 50 ft. 



^^-_ ^-^ — __r— __— r 3-~Za 7- Erie shale in place. 



with its muck bed and buried timber, is the counterpart of others that 

 are found behind the ridges in a great number of localities. Similar 

 swamps may be seen behind the beach ridges now forming along the 

 present shores of Lake Erie and Lake Michigan. 



Profile Section from Lake Erie to Grand River. 



HORIZONTAL SCALE, 1 INCH TO 1% MILES. 



In his report on Lake county, Mr. Read gives a profile section of the 

 lake ridges, with the following explanatory notes : 



" In Madison township the slope from the Lake rises more gradually than further 

 west, and the lake ridges are more regular and are better denned. The section given 

 below reaches from the Lake through Madison Center to the bed of Grand river. 



