GLACIAL WATERS IN CENTRAL NEW YORK 



35 



During the life of the Syracuse outlet the site of the city was 

 occupied by a shallow lake extending south up the Onondaga 

 valley, and fed by glacial waters from the west. The central and 

 southern parts of the city are built on this detrital plain or delta 

 built in the shallow Syracuse lake, which deposits also form the 

 present floors of the low channels at Syracuse. These plains are 

 at least 20 to 30 feet beneath the Iroquois level. The valleys in 

 their deeper sections are not the erosional work of the later glacial 

 drainage but antedate the epoch which we are studying, and as 

 passes between the drumlin masses they are part of the problem 

 involving all the lower channels from Palmyra to Syracuse [see 

 p. 20]. 



In the preceding chapter the terrace levels on the Cedarvale 

 South Onondaga delta were referred to the levels of outlets to the 

 eastward, and we find these correlating outlets in the Jamesville 

 series of channels. The following comparison of the levels of 

 terraces and outlets will show the relationship. 



PRINCIPAL TERRACE LEVELS ON 

 CEDARVALE-SOUTH ONONDAGA 

 DELTA 



Upper terrace 860-840 



Mesa terrace ±75° 



Middle terrace 660 



South Onondaga ter- 

 race 640-600 



Lower terrace 560 



Lowest terrace 500 



ALTITUDE OF OUTLET CHAN- 

 NELS, JAMESVILLE SERIES 



Reservoir channel. ... 840 

 Jamesville channel. ... 760 



Unnamed channels. . . . 700-600 



Railroad channel 540 



Syracuse channel 400 



In such comparison we must remember that the channels have 

 suffered deepening, and that we find them with the depth attained 

 when the river saws abandoned their work. We can not generally 

 determine the amount of down-cutting by the stream, but no 

 channel can be initiated at a level higher than the bottom of the 

 antecedent and deserted channel. Another uncertain element is 

 the relation of the lake surface to the delta terrace. A third ele- 

 ment is the land deformation, which may not be neglected when 

 the features are on far separated parallels. The east-west deforma- 

 tion in this district is small, but there may be a northward uplift 

 of 2 or 3 feet per mile. In the above figures there is a lack of pre- 

 cision as they are estimated from the map contours and may vary 

 a fraction of 20 feet, but accurate measurements will confirm the 



