582 FRANK CARNEY 
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 Bluff 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. 1.). The striae below the 1,100-foot contour 
measure 5.65°-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 at an earlier stage. 
In any case, the striae indicate that this slope was leeward at least 
part of the time, hence the subdued erosion. 
In the veneer of drift we note a conspicuous number of very weath- 
ered stones. These constituents in many instances are rotten, going 
to pieces under a blow of the hammer; others show in cross-section a 
surface altered zone, one-quarter to one-half inch wide. Even the 
pitted quartzite bowlders are not rare. 
Eastern slope oj Bluff Point.—On this opposite slope of the bluff a 
roadway leading northward from Dunning’s Landing makes an expo- 
sure of highly weathered material just north of Wiliam T. Morris’ 
cottage. This is the only section which suggests a concentration of 
rather uniformly altered drift constituents; neither the location nor 
the weathered condition of this exposure necessarily implies old 
drift. 
About one-half mile south of Dunning’s a recent stream channel 
reveals the contact of two distinct types of drift. The upper horizon 
is the familiar Wisconsin which here overlies a semi-indurated bluish 
till. This latter is fresh in comparison with the overlying Wisconsin 
which at this point is about 6 feet thick (Fig. 2.). 
tH. L. Fairchild, Bulletin of the Geological Society of America, Vol. XVI (1905), 
pp- 64,65; R.S. Tarr, American Geologist, Vol. XX XIII (1904), p. 286. 
2 James Hall, ‘‘Geology of the Fourth District,’ Natural History of New York, 
Part IV (1843), p. 1450. 
