NEW YORK STATE MUSEUM 



variation in level, because the Utica lake was not a permanent 

 level, but had a falling surface, and because stream deltas are 

 themselves of variable altitude. 



4 Delta plains of the Clinton waters. These levels will range 

 from about 600 feet up to perhaps 1100 feet. The most con- 

 spicuous will be at about 600 up to 800 feet, and correlate with 

 the lowest of the glacial stream channels that drained the Clin- 

 ton waters eastward. On plate 2 these channels are shown. 

 The lowest cutting forms the concave slope heading near New 

 Hartford and passing around the north base of Devereux hill, 

 through the soufh edge of the city of Utica, with altitude of 

 about 600 feet. The next higher level is about 700 feet, the 

 channel being an earlier cutting on the same slope as the one 

 just mentioned. The strongest level will be at 750 to 800 feet, 

 produced by waters held for a long time at about 740 feet alti- 

 tude, while the escape was through the strong channel south 

 of Devereux hill and the Forest Hill cemetery, called here the 

 " Reservoirs channel." For the Clinton valley the level at this 

 stage was determined by the outlet having nearly the same 

 altitude and heading about 2 miles northeast of the town. This 

 level in particular will be found in many places, but running 

 to higher than 800 feet in the smaller stream valleys. The 

 level constitutes a conspicuous plain and terrace in the Sauquoit 

 valley above and below Chadwicks. 



5 Delta plains of the summit levels. The highest water level 

 to be found in the upper or southern section of the Oriskany 

 valley must be at about 1150 feet, correlating with the southern 

 outlet near Bouckville. In the Sauquoit valley the correspond- 

 ing level will occur, but a higher, summit level there will be about 

 1270 feet, correlating with overflow at Richfield Junction. 



There are reasons why the phenomena of the water planes 

 are weaker at the higher levels. The lakes were less stable, 

 new outlets opening on the steep slopes; the valley walls are 

 steeper, giving less foothold for the delta accumulations; and 

 the amount of available detritus in the grasp of the lateral 

 streams was less. 



In all these several stages of lacustrine levels considerable 

 variation in the hight of the deposits must be expected; due 



