\ 78 The American Geologist. March, 1894 
What dosed this channel ? Two explanations may be given; 
first, warping of the earth's crust during the Ice age; second, 
deposition of glacial material and of the marine clays. De- 
formation sufficient to hold the lake at its present hightmust 
have included ;i considerable and well denned uplift. If this 
was since the formation of the marine terraces, it must have 
distinctly distorted them. If it was during the Glacial period 
it would not probably occur until the ice had disappeared from 
that region, and as soon as that happened the sea came in and 
began building its terraces, which therefore must have been 
affected by the differential elevation. No evidence of such 
uplift was found. On the contrary, in going from south to 
north, the marine deposits of sands and clays evidently be- 
come much thicker, and the foot-hills on either side are more 
buried by them until, north of the lake, they are entirely cov- 
ered by the great clay plain of the St. Lawrence. We should 
therefore expect this deep channel to extend under the clay 
plain to the north, at a depth of 400 feet or more, as a buried 
outlet to the St. Lawrence. My brief search revealed no evi- 
dence of importance, though it led me to believe that the 
outlet was not from Missisquoi bay. 
The Hudson and Chami-lain Valleys. 
The divide between the Pawlet river and Black creek was 
not examined, but seems to be a sand plain at about 400 feet.* 
The lowest divide is that crossed by the canal from Whitehall 
to Ft. Edward at 150 feet, at the same hight as the ends of 
the canal, Ft. Edward and Whitehall. A continuous sand 
plain extends from one place to the other, and is so nearly 
level that while the divide is really at Ft. Ann, eleven miles 
from Ft. Edward, yet the canal flows toward Whitehall, ex- 
cept the last three miles near Ft. Edward. In the town of 
Whitehall, the canal drops 50 feet to the level of the lake. 
The two valleys narrow rapidly to Ft. Ann, where is seen a 
typical divide between streams, entirely of rock, showing lit- 
tle evidence of glacial or postglacial erosion, and not at all 
resembling a river channel. It is not probable that any large 
Stream ever Mowed across this divide for more than a very 
short time, and the expression, sometimes seen, "the Hudson 
— Champlain valley," seems to me a misuse of terms. 
*Geology of Vermont, vol. i, p. 128. 
