1877. ] Geography and Exploration. 51 
the action of water and frost upon shale, and we can readily see that the 
conditions which obtained in the formation of these valleys could never 
explain the deep, well-marked valleys of Six Mile Creek and the Cayuga 
Inlet, with their sloping banks and knolls and terraces. These deep, 
well-worn valleys are undoubtedly the result of glacial action. The 
mass of ice which filled the Cayuga Lake basin, dividing at its southern 
extremity, one part — the larger — flowed to the south, wearing down 
the Inlet valley, and the other traversed the Six Mile Creek valley, both 
of which were occupied by preglacial streams. ‘The scratches on the 
polished surface of the underlying rocky table, as seen at the quarry in 
front of the buildings of the Cornell University, on the eastern edge of 
the basin, indicate that the glacier followed a direction a little east of 
south, corresponding with that of the lake. Among the drift accumula- 
tions are found bowlders of Oriskany Sandstone, and masses of Hamilton 
shale, formations which occur to the north, together with small granitic 
bowlders. The valley of Six Mile Creek furnishes some special exam- 
ples of the drift phenomena. In several places its old channel has been 
completely choked up with masses of morainic débris about which the 
present stream has been obliged to cut its way through deep cafions. 
It was in this valley, at Mott’s Corners, a few miles from Ithaca, that the 
remains of a mastodon were discovered several years since.’ 
In the cafions of this creek and in the gorges of those streams of 
more recent origin trap dykes are not uncommon. In some cases they 
thin out before reaching the surface, as in the cañon of Six Mile Creek 
above Green Tree Falls. There is no apparent displacement of the 
strata, the dykes being merely cracks filled with igneous rock. 
Intimately related to the geology of Ithaca is the problem concerning 
the origin of Cayuga Lake. At present this has not been satisfactorily 
solved. Theories have been advanced, but as yet none are sufficiently 
matured. A consideration of this subject will require a careful and de- 
tailed study of the entire lake system of Western New York. While 
Ithaca does not present that field of study in structural geology to be 
found in a mountainous or disturbed region, it does offer many attrac- 
tions to the collector and student of superficial deen e W 
Sımoxps, Cornell University. 
GEOGRAPHY AND EXPLORATION. 
EXPLORATIONS OF THE POLARIS EXPEDITION TO THE NORTH POLE. 
— The reports of the scientific results of the Polaris expedition have 
been delayed simply, we are sorry to say, for want of means for publica- 
tion. Dr. Bessels, the scientist of the expedition, made valuable collec- 
tions of animal life at Polaris Bay, between latitudes 81° 20! and 81° 50! © 
N., and soon after his return placed in the writer’s hands the insects. and 
fresh-water crustacea. Now that the English expedition has returned i it 5 . 
1 See American Naturalist, v. 314. 
