GLACIAL WATERS IN THE LAKE ERIE BASIN 



15 



2 miles southwest of Portland, and one 2 miles northeast of 

 Brocton. All these fragments should correlate with recognized 

 moraines. 



The close association of the moraine deposits on the land slopes 

 facing Lake Erie with the scourways of the glacial drainage and the 

 work of the glacial lakes must be clearly recognized in order to 

 understand the various and intricate phenomena. The several 

 maps suggest this intimate relationship. 



GLACIAL DRAINAGE CHANNELS 



These effects of the glacial waters are not so prominent as the 

 lake shores but are much more widely distributed. They are 

 not so conspicuous features to the untrained eye as the bars and 

 continuous beaches, but when once recognized they are unmistaka- 

 ble. The more definite channels are valleys or notches or terraces 

 of various sizes, in either rock or drift, and with or without present 

 streams. The stronger of them are evident in their origin, having 

 all the characters which distinguish the work of streams, namely, 

 fairly uniform grade and width, curves with radius proportionate 

 to size or strength of stream, definite banks, and with correlating 

 areas of drainage on the one hand and receiving water bodies on 

 the other. All gradations will, of course, be found down to small, 

 shallow and indefinite scourways made by short-lived currents, 

 even to those of doubtful origin. Along steep slopes the stream 

 cutting is commonly shown only by more or less decided notches 

 or shelves or terraces in the slope, the ice having been the lower 

 wall of the channel. The removal of the ice has in these cases left 

 us the anomaly of water courses with only one confining bank, 

 the down-slope wall being, so to speak, in the air. We need to 

 restore the bank of ice in our imagination. Plates 2-6 give the loca- 

 tion of these ancient and extinct channels. It must not be thought 

 that the water channels are unique or peculiar to this region, 

 for they are found wherever the great glacier was holding bodies 

 of water in depressions of land slopes. They occur not only through- 

 out the entire district described in this paper but eastward along 

 the south slope of the Ontario basin to Rome and down the Mohawk 

 valley to Little Falls. The largest glacial channels in New York 

 lie in the Syracuse region, with huge cataracts that rivaled Niagara 

 in size and were the predecessors of Niagara in fact, as they carried 

 the falling Warren waters eastward to lower levels. 1 



1 Descriptions of the channels and cataracts in the Syracuse district and 

 eastward will be found in papers by the author in the 20th, 21st and 22d 

 annual reports of the New York State Geologist. 



