60 GEOLOGY OF OHIO. 
arm of the Lake, into which the ridges were deflected on the west side, 
where the slope was gentle and the material soft. On the east side the 
waves raised by westerly winds cut terraces at corresponding elevations. 
The valley of Rocky river, near its mouth, is a narrow gorge of quite re- 
cent date, and the manner in which the ridges terminate on its margins 
show that it had no existence when they were traced on the surface ; 
hence we are justified in concluding that all the rock-cutting of the 
Rocky river gorge has been done since the ridges were formed. The 
fact that the lower ridge runs directly across the delta plain at the 
mouth of the Cuyahoga proves not only that the valley was filled to 
this point when the ridge was formed, but since this ridge is here un- 
derlaid by about 3800 feet of Drift deposits, the upper part consisting of 
fine laminated clays and stratified sand and gravel, that glaciers could have 
had no agency in its formation. The succession of beaches on the west 
side, and the terraces east of the valley at Cleveland, are shown in sub- 
joined wood-cuts. 
PROFILE SECTION OF LAKE RIDGES, CLEVELAND, WEST SIDE. 
SRE ear 
asa ZAY7 
Terraces East of Cleveland, 
CLEVELAND. 
OLD CUYAHOGA DELTA. WAVERLY 
CUYAHOCA 
RIVER 
LEVEL OF LAKE ERIE. 
ERIE SHALE 
1. First Terrace, 165 feet above the Lake. 
2. Second Terrace, 210 feet above the Lake. 
3. Drift deposits forming the old Delta of the Cuyahoga and filling the old valley. 
Kast of Cleveland the lake ridges continue into Pennsylvania and 
western New York, and probably connect with the series observed on the 
south shore of Lake Ontario; for when the water stood at the level of 
the lowest of the ridges of Lake Erie, they overtopped the divide which 
separates Lake Erie from Lake Ontario. In the counties of Lake and 
Ashtabula two distinct ridges are usually traceable, and sometimes one 
