220 Carney — Possible Overflow Channel of Ponded Waters. 



farm of W. L. Spooner, forming its northern wall, at the same 

 time cutting a bench in the rock of the southern wall ; crossing 

 the highway, it continues eastward through the property of 

 Samuel McElvee. The development attained by this outlet 

 does not indicate a very long stage of the lake at this level, 

 approximately 1010 feet. 



Base-level of channels. — Lake Newberry overflowed at Horse- 

 heads ; since the outlet is heavily aggraded, it is possible that 

 this lake at one time rose above the 900-foot contour, but later 

 removed some of the glacial outwash ; the level of its deltas, 



Fig. 2. Looking eastward through Channel No. 1. 



however, preclude much allowance for cutting down of the 

 overflow channel. This altitude, then, was the intermediate 

 base-level of the streams that led the ponded water of Keuka 

 valley into Seneca valley. The intakes of the channels represent 

 the water levels of the former valley ; this level minus the 

 gradient of the outlet streams should be the altitude of Lake 

 Newberry, or 900 feet. 



Correction for differential movement. — The whole Great 

 Lakes region in post-Wisconsin time has been subject to a 

 deformation which has either depressed the areas in the west 

 and south, or upraised those in the east and north, or, by a 

 combination of these movements, has produced the same result. 

 The amount of this deformation in the Finger Lake area 

 has been computed at 2*7 feet per mile.* The channels we 



*E. S. Tarr, Journal of Geology, vol. xii, pp. 79-80, 1904; data com- 

 municated to Professor Tarr by Dr. G. K. Gilbert. 



