GLACIAL WATERS IN BLACK AND MOHAWK VALLEYS 23 



Taking- the several elements of the problem into consideration the 

 only pass leading out of the Mohawk basin which correlates with 

 the widespread sand plains having an altitude of 1400 feet and up- 

 v/ards is the one at the head of the Otsego valley, between Spring- 

 field Center and Summit lake. A northward uplift of about two 

 feet per mile brings this channel, 1360 feet, into close accord with 

 the high sand plains at Forestport, Grant, Gray, Ohio and 

 Devereaux-Stratford. 



The Summit lake channel is in limestone. The map makes the 

 divide a mile north of the lake but the cut channel is at and south 

 of the lake. Going north from Springfield Center singular heaps 

 and knolls of limestone rubbish are seen, which are clearly piled 

 by plunging or cascading waters. Beyond these the channel is bare 

 limestone in ridges and hollows with lateral recesses and terraces. 

 North of the lake and swamp are moraine knolls at the head of the 

 pass, at about the altitude of the lake. The aneroid and hand level 

 made the stream-cut limestone ridges south of the lake somewhat 

 higher than the lake. It would seem that the original rock divide 

 must .have been in the limestone south of the lake. 



The morainal surface at the head of the pass and the irregular 

 bed in the eroded limestone indicate that the river did not have 

 length of life sufficient to level or smooth the channel entirely across 

 the col. The head of the pass may have been ice-obstructed; and 

 it is possible that the flow in this pass was directly from across the 

 strait of ice which filled the valley on the north. This seems the 

 probable locality where the early ice-bound waters, held about the 

 exposed foothills of the Adirondacks, would find ultimate escape. 



No clear separation can now be made between the Adirondack 

 waters which were drained across the ice and the early lake in the 

 ice-free section of the valley. As most of the features described 

 in this chapter lie in the area of Herkimer county the name Herki- 

 mer lake may be properly given to the waters, without close dis- 

 crimination as to altitude and outflow.^ 



The Summit lake channel correlates with the 1400-1440 feet sand 

 plains, the difference of 80 feet giving the theoretical uplift of two 

 feet per mile, with some allowance for depth of the river and down- 

 cutting of the outlet. In the same way the Cedarville channel, 1220 



1 The sand plains at Forestport are in Oneida county; part of those 

 at Devereaux-Stratford are in Fulton county; and the Summit lake outlet 

 is just over the line in Otsego county. The Cedarville channel, which 

 was the outlet of the positively open-valley water, is in Herkimer county. 



