328 W. UPHAM — PREGLACIAL AND POSTGLACIAL VALLEYS. 



shore of lake Erie. Thence the Cuyahoga river flows first about forty 

 miles southwestward to its great bend close north of Akron, there turn- 

 ing to a general course slightly west of north which it holds through its 

 lower thirty miles, entering lake Erie after passing through the central 

 part of the city of Cleveland. This paper considers chiefl}'' the last four 

 miles of the Cuyahoga valley which are comprised within the limits of 

 Cleveland. The level of the river in its stage of low water along this dis- 

 tance, from the junction of Big creek to its mouth, is the same as lake 

 Erie, or differs onl}^ by a descent of 1 or 2 feet. Along all the south-to- 

 north part of the river it flows now in its preglacial valley, which has 

 much drift beneath the stream. 



PREGLACIAL WIDTH AND DEPTH. 



Where the Cuyahoga river enters the county of tliis name, at a distance 

 of about thirteen miles from its mouth, the rock l^ottom of the preglacial 

 valley is known by wells bored for oil, according to Professor J. S. New- 

 berry in the reports of the Geological Survey of Ohio, to be 220 feet below 

 the present river, or approximatel}^ 175 feet below the level of lake Erie. 

 Again, at the junction of Kingsbury run in Cleveland, two and a quarter 

 miles from the mouth of the river, a well bored b}^ the Standard Oil Com- 

 pany penetrated 238 feet of drift, to the depth of 228 feet below the river 

 and lake, and 1<S feet below the bottom of the lake at its dee})est i)lace, 

 before entering the bed-rock. During preglacial times the Cuyahoga 

 here eroded a valley twice as dee}) as that which it now has, with a width 

 nearly the same as now — that is, about one mile, excepting within the 

 five miles next to the present lake Erie, where the old valley expanded 

 gradually to be aijout seven miles broad before its bluffs were merged 

 with the general escarpment south of the great lowland whicli now is 

 covered by the lake. 



PARTIAL FILLING WITH GLACIAL DRIFT. 



The section of the drift 238 feet dee)) in the well at the mouth of Kings- 

 bury run consisted mainly of till (called " blue clay " by Newberry), with 

 occasional layers or seams of sand and gravel, ranging from 1 to 5 feet 

 in thickness. The till here also reaches in the bluff's about 50 feet above 

 the top of the well, giving nearly 290 feet as the whole depth of the glacial 

 drift deposited in this broad part of the valley near its opening out to the 

 plain of the lake basin. At the shore end of the water-works tunnel, a 

 mile west of the ])resent mouth of the river, the depth of drift to the bed- 

 rock was found to be 78 feet below the lake level ; at the engine-house of 

 the water works, about a half mile nearer the center of the valley, the 



