WARREN UPHAM — RELATIONSHIP OF GLACIAL LAKES. 1:85 



With this hitter explanation 1 fully agree, and therefore place the descriptive word 

 "glacial" before the names of these lakes. 



In a paper read a year ago before this Society I presented a general review of the 

 glacial lakes of Canada, in which the relationship of lakes Warren and Iroquois 

 and the sea level in the Charnplain epoch was found to imply for the ( !hicago outlet 

 of lake Warren nearly the same altitude as now, or about 600 feet above the sea. 

 It was also shown that lake Iroquois, while outflowing at Rome, New York, was at 

 first probably 100 feet or less above the sea, but that its basin was uplifted, while 

 its outlet continued at Rome, until the height of this lake was about 300 feet above 

 the sea. The present paper, which is supplementary to that of last year, after 

 briefly noticing the three glacial lakes Warren, Algonquin and Iroquois in the 

 basins of the great Laurentian lakes, is chiefly designed to call attention to the 

 expansion of lake Iroquois until it became united with the glacial lake winch filled 

 the valley of the Hudson and the basin of lake Charnplain. 



Lake Warren was contemporaneous with the glacial lake Agassiz, which occupied 

 the basin of the Red river of the North and the district of the present great lakes 

 of Manitoba, and it may have continued until lake Agassiz began to outflow north- 

 eastward. It belonged to stages in the departure of the ice-sheet which appear to 

 have permitted confluent sheets of water to stretch as a single lake from the western 

 end of the basin of lake < >ntario over the whole or the greater part of the four higher 

 Laurentian lakes. Its outlet was across the watershed near Chicago, between lake 

 Michigan and J >es Plaines river, at a height of about 12 feet above this lake and 

 595 feet above the sea, where now a canal has been cut through on the same level 

 with the lake. 



Lake Algonquin, which was the reduced representative and direct descendant of 

 the somewhat earlier lake Warren, occupied the basin of Georgian bay and lake 

 Huron and perhaps portions of the basins of lakes Michigan and Superior. It out- 

 flowed for some time through Balsam lake and the river Trent to lake Iroquois, 

 then restricted to the lake Ontario basin. Later it was tributary by the way of 

 lake Xi pissing and the Matta wan river to the northward expansion of lake Iroquois, 

 then filling the lower part of the Ottawa basin. The altitude of lake Algonquin 

 above lake Iroquois in their earlier stages was approximately 200 feet, and in the 

 later stages of both these lakes it was probably 50 to 150or 200 feet, increasing with 

 the gradual Uplifting of the country between lake Huron and the Saint Lawrence. 



Lake Iroquois began to exist as soon as the recession of the ice-sheet uncovered 

 the Mohawk valley. The previously existing lake Warren was then drawn down 

 below the avenue of outflow at Chicago, and became changed, as Mr. Gilbert has 

 shown, into lakes Algonquin and [roquois, the former either extending from the 

 basin of lake Huron into those of lakes Michigan and Superior or receiving tribu- 

 tary rivers from those lakes, and the latter filling the basin of lake Ontario and 

 receiving the outflow from the former. In mapping the highest shore of lake 



Iroquois ill the Ontario basin, Professor Spencer calls this the western portion of 

 lake Iroquois, and states that this lake spread to the northward and eastward over 

 the ureal triangular area between the Ottawa and Saint Lawrence rivers, sending 



an arm far up the < Mta.wa \ alley. 



Bu1 none of the writers on these glacial lakes have studied the question, Where 

 was the ice-sheet latest a barrier across the Saint Lawrence basin? The directions 

 of glacial stria' and transportation of drift answer that the ice-sheet in this region 



during the closing stage of glaciation was thickest on a hell crossing the Saint 



LXVI— Bum.. Soc. \m.. \'<.i . ::. 1801, 



