PRE-WISCONSIN DRIFT IN FINGER LAKE REGION 575 
also localities where the deposition of ice-débris was more pronounced. 
The combined effects of glacial erosion by the different invasions has 
not removed all the residual soil, the regolith of preglacial weather- 
ing.*’ Nor would asucceeding ice-sheet carry off all the drift deposited 
by a preceding invasion. Therefore it remains to inquire into the 
conditions most favorable to the deposition, and least favorable to 
the ice-erosion of former drift-sheets. 
Fic. 2.—An east-west section showing contact of the two drifts as exposed south 
of Dunning’s Landing. ‘The wavy, irregular line marks the upper surface of the blue 
till. 
‘ 
Deposition oj drijft.—Aside from the ground moraine, the thickness 
and irregularity of which attest the heterogeneously distributed load 
which is being carried by the retreating ice, the localized deposits 
of débris represent in the first place a reaction of climatic factors 
that cannot be specifically determined; and, in the second place, the 
tH. L. Fairchild, Bulletin of the Geological Society of America, Vol. XVI (1905), 
pp- 53-55; R.S. Tarr, American Geologist, Vol. XX XIII (1904), p. 287, and F. Carney. 
The writer’s unpublished notes,on the Moravia (N. Y.) quadrangle afford further 
proof of the presence of preglacial weathered products in place. 
