Geoloiilcal Soriefii nhd A. A. A. S. Jfeefiiit/s. — Cpli'iju. 251 
-ment by vast ice-sheets, and the second or Champlain epoch bein^ dis- 
tinguished by the subsidence of these areas and the departure of the 
ice, with abundant deposition of both glacial and modified drift. Epei- 
rogenic movements, first of great uplift and later of depression, are thus 
regarded as the basis of the two chief time divisions of the Ice age. 
Each of these epochs is further divided in stages, marked in the Glacial 
epoch by fluctuations of the predoiiiinant ice accumulation and in the 
Champlain epoch by successively diminishing limits of the waning ice- 
^heet. 
Prof. HiTCKCocK, in discussion, said that his view of the Champlain 
time is that of a cold rather than a mild epoch, judging from the boreal 
character of the fossils. He congratulated the glacialists on the grow- 
ing harmony of their views and tht? diminishing size of the differences 
which separate them. 
QlaciaJ Phenomena heiicpe II Lake Cham plain and Lake George and 
the Hudson. G. F. Wright, Oberlin, Ohio. This paper gave a detailed 
description of the stratified gravel, sand and clay, and of the till (with 
one conspicuous drumlin), in the valleys crossing the water divides south 
of the two lakes named. Lake George, 225 feet above lake Champlain 
and 325 feet above the sea, is dammed by deposits of glacial and modi- 
fied drift at both ends, and is shallowest at the middle of its length, 
where the Hundred Islands lie. This confirms the conch;sion of Mr. S. 
Prentiss Baldwin, based on his field studies of the district three years 
ago, that the basin of lake George was drained in preglacial times by 
two streams, one running northerly and the other southerly. The valley 
of the northwardly flowing stream, now filled with drift, lies west of the 
present outlet and is traced to its junction with lake Champlain about 
halfway between Ticonderoga and Crown Point. 
Delta gravels at Glens Falls, Sandy Hill and Schenectady have an 
elevation of 300 feet, or more, above the sea; but the stratified clays and 
sand of the Hudson valley eastward and southward, and of the divide 
between lake Champlain and the Hudson, reach only to 180 feet above 
tide. The watershed in the valley south of lake George is estimated to 
be only 30 or 40 feet above that lake: and the canal from the Hudson 
river -to lake Champlain has a summit level of twelve miles only about 
150 feet above the sea. The glacial striie all bear southwestward 
athwart the prevailing course in Vermont and the east edge of New 
York, the difference in direction being probably attributable to local 
southwesterly deflection during the departure of the ice-sheet. 
Whirlpool of Niai/ara. G. W. Holley, Ithaca, N. Y. Attention was 
directed to the parallelism of the river below the falls with the joints in 
the Niagara limestone, and the author rejected the theory that a drift- 
filled preglacial channel extends from the Whirlpool to St. David's. 
Prof. Spencer, in discussion, said that he had made excavations upon 
the soft northwestern side of the Whirlpool basin, where the buried 
channel has been supposed to begin, and found rock there up to the 
hight of 190 feet. 
