230 Proceedings of the Ohio State Academy of Science 



difficulty, perhaps, in realizing that Lake Whittlesey, or Manmee, 

 probably endured quite as long as the present Lake Ontario. 

 When, however, we compare the rock cliffs now bordering the 

 shore of Lake Erie, the constructed beaches, the barriers, the 

 lagoons isolated by development of new bars, the dune sands 

 reaching inland from the shores, with the identical phenomena 

 of these lakes of the past and see how Httle they differ in scale, 

 in spite of the denuding agencies that have operated upon them 

 since they were formed, then we can better comprehend the very 

 appreciable time intervals represented by the successive stages in 

 the past history of the Great Lakes. 



The shore of Lake Maumee in the vicinity of Cleveland was 

 irregular because of the embayments occupying the Rocky river 

 and Cuyahoga river valleys. The arm of the lake extending 

 southward into the former valley was crescent shaped, the west- 

 ern being the shorter of the two segments ; but the prevailing 

 winds, by constructing spits and bars, gradually brought that 

 part of the shore into alignment with the general direction of the 

 beach. A more detailed discussion of this is given later. 



The valley of Big Creek also formed a small bay during the 

 early part of this lake stage ; here again, on its western side, bars 

 gradually developed and straightened the shore line. 



The mature Cuyahoga valley was occupied by water of the 

 Maumee level, reaching southward through the entire length of 

 the Cleveland sheet. This arm was the drowned portion of the 

 Cuyahoga valley, for the tributaries of which the lake consti- 

 tuted a local base level into which they spread deltas. 



The shore of the Lake Whittlesey stage shows no evidence 

 of a bay in the meridian of Rocky river ; there was a slight curve 

 in its outline where the water fronted the lower part of Big 

 creek. In the Cuyahoga valley, however, this stage extended 

 southward through the Cleveland sheets ; its altitude is recorded 

 by terraces cut into the deltas of the preceding stage, as well as 

 by the extension of these deltas during the existence of Lake 

 Whittlesey. 



The Warren shoreline is characterized by but one embay- 

 ment, that occupying the Cuyahoga valley which was ponded the 

 entire length of the Cleveland sheet. 



