14 
Frank Carney 
an earlier deposit of drift suffer great erosion. Consequently 
valleys of this type are best fitted for the preservation of pre- 
Wisconsin drift. In the area covered especially by this paper two 
segments of such valleys, one extending eastward from the vicinity 
of Branchport (Penn Yan quadrangle), the other extending west- 
ward from Dresden (Ovid and Penn Yan quadrangles), have been 
studied. 
LOCATION AND DESCRIPTION OF THE PRE-WISCONSIN DRIFT 
IN QUESTION. 
First indication of such drift. In the area from Skaneateles to 
Keuka Lake the writer has often noted the highly weathered con- 
dition of smaller bowlders, both on the surface and in cuts in the 
drift. Later acquaintance with the older drift in Ohio has led 
him to give further attention to this observation. These scattered 
rather rotten crystallines may or may not suggest drift of different 
ages. 
It is not likely that the first or even the second ice-invasion 
removed all the residual products of preglacial weathering. This 
much weathered material would constitute a larger part of the 
first than of any later drift-sheet. And from the fact that residual 
decay is noted beneath the Wisconsin drift^^ it follows that some 
preglacial weathered products have withstood several periods of 
ice-erosion. 
Western slope of Blujf Point. This elongated ridge, drumlin- 
like in outline and slopes, peninsula-like in reference to the arms 
of the lake,^^ rises about 715 feet above the level of Keuka Lake. 
Its longer axis is meridional (fig. i.) The striae below the iioo- 
foot contour measure S.65°-28° W. So on the western slope of the 
bluff the work of the ice was dragging and plucking rather than 
abrading. But if these striae represent only the final ice-motion in 
the area, then the work of the glacier may have been more vigorous 
H. L. Bulletin of the Geological Society of America^YoX. xvi (1905), 
pp. 64, 65; R. S. Tarr, American Geologist, vol. xxxiii (1904), p. 286. 
James Hall, “Geology of the Fourth District,” Natural History of New York, 
Partly 459. 
