414 Frank Carney \ 
^ While it is probably impossible to be certain about the chronol- ! 
ogy of these deltas, nevertheless in discussing their genetic rela- I 
tions an attempt is made to arrange the associated water bodies in 
their chronological sequence. In this study only one type of 
observation has been made in addition to verifying the earlier work i 
of Fairchild and of Watson on the high-level lakes of the region. 
The overflow channels with which these men have correlated the 
deltas studied are all located along general drainage lines to the 
south and west of the water bodies under discussion. After hav- | 
ing mapped the bands of thickened drift, one notes that the eastern i 
margin of the Cayuga lobe so abutted the rock salients as to form j 
intermediate overflow levels between the spillways that have t 
already been located. In accordance with these observations i 
the several deltas will now be considered in the order in which it ! 
is thought they were developed. j 
The position of the ice as denoted by the morainic loop ' 
southward from Freeville held up in front of it a slight body of 
Water which overflowed through the Dryden valley with a spill- I 
way approximately 1207 feet in altitude. This is the first static 
body of Water formed on the quadrangle as the ice retreated, i 
No typically developed delta was observed correlating with it. 
In the wide valley, however, immediately north of Dryden village 
may be seen on the eastern wall a well formed alluvial cone which 1 
presumably correlates with this level. 
• But the delta ‘A’’ at McLean, having a general altitude of 
1140 feet, obviously represents an overflow channel, one wall 
of which was the ice itself, the other the northwestward slope of 
Turkey Hill, located on the Dryden sheet. The water thus had 
its ultimate outlet through Cascadilla valley by way of Ellis, and 
thence into the glacial lake that occupied Sixmile creek. 
C. ” As already stated, this delta is associated with a morainic 
loop of which it almost forms a part. Its level coincides closely ' 
with that of ''AC but it is not of contemporaneous development; | 
while these two deltas correspond in altitude, "C’ is of much j 
later origin; its position is such that a marked accumulation of ! 
aggraded material developed in a fairly short time. The loop of j 
drift reaching across the valley at this point attests a stationary | 
position of the ice for some period during which there poured ! 
along the eastern side of this ice-tongue a vigorous stream whose 
gradient suddenlv changed, as may be observed on consulting 
