TITLES OF PAPERS. 13 



detailed record is supplied by Newberry's report, the far greater part of all the 

 section is clay (probably nearly all till). In that well (with the bluff above it) 

 the till has a thickness, next below the Late Glacial delta sand, of 150 feet before 

 coming to the first observed seam of modified drift; but in the lower part of the 

 section a few beds of coarse gravel, contained in the till, indicate fluctuations of 

 the glaciation in its early stages, with free drainage conditions, the altitude being 

 greater than now and the lake area not yet depressed to be a closed basin. 



Postglacial River Erosion in Cleveland and along this Bed of Lake Erie. 



The map accompanying my previous paper, already referred to, shows very con- 

 spicuously the modern valley which the Cuyahoga river has cut through its Late 

 Glacial delta and into the drift-sheet beneath. It w r as also observed in that paper 

 that this recent erosion followed shortly after the glacial recession permitted an 

 avenue of drainage from the Lauren tian lakes area eastward by the Mohawk valley, 

 as is known by the absence of any delta in the margin of lake Erie resulting from 

 the Cuyahoga erosion since the lake attained its present form. 



When the glacial retreat uncovered the Mohawk valley, this region was depressed 

 toward the north and northeast, in comparison with its altitude today. But soon, 

 while yet lakes Algonquin and Iroquois existed, held in by the waning ice-sheet 

 on their northeast sides, the former being tributary to the latter by a large stream 

 which I have called the river Erie, flowing in the course of the Saint Clair and Detroit 

 rivers and along the bed of lake Erie, the country was moderately uplifted, with 

 increasing extent of elevation from west to east-. Thus the east end of the broad 

 Erie river valley rose soon to such height that a lake began to be held in its shallow 

 basin and grew in westward extent until it reached its present area, covering the 

 channel of the river Erie, which appears to be represented by the deepest sound- 

 ings of the lake. It also covered the alluvial and delta deposits of the formerly 

 longer Cuyahoga river, tributary to the river Erie and the expanding lake Erie. 

 The subsequent and most recent action of the Cuyahoga river has been to fill with 

 alluvium the lower part of its modern gorge within the limits of the city of Cleve- 

 land, where it had been eroded somewhat below the present river and lake level. 



ORIGIN AND AGE OF THE LA URENTIAN LAKES AND OF NIAGARA FALLS 



BY WARREN UPIIAM 



The paper is printed in full in the American Geologist, vol. xviii, pp. 

 169-177, September, 189(3. 



GLACIAL FLOOD DEPOSITS IN CHENANGO VALLEY 

 BY ALBERT P. BRIGHAM 



The paper is printed in full in this volume. 



CORRELATION OF WARREN BEACHES WITH OUTLETS AND MORAINES IN 



SOUTHERN MICHIGAN 



BY F. B. TAYLOR 



This paper is printed in full in this volume. 



