g4 THE GLACIAL LAKE AGASSIZ. 



and the Churchill, and probably also the upper Mackenzie basin, continued 

 to be tributary to this lake through all its lower stages of outflow to Hudson 

 Bay. With this addition, the area of the glacial lake basin was not less 

 than 500,000 square miles. 



Extensive areas bordering the Peace River are described by Dr. G. M. 

 Dawson as "covered .supei-ficially by fine, silty deposits, resembhng those 

 of the Red River Valley, and doubtless indicating a former great lake or 

 extension of the sea in the time immediately succeeding the Glacial period." 

 The exploration of ancient shore-lines is very difficult in that generally 

 forest-covered region, and it must be many years before the boundaries and 

 outlets of former bodies of water in the basins of the Peace and Athabasca 

 rivers can be mapped; but it may be predicted with reasonable confidence 

 that these basins, now drained to the Mackenzie and the Arctic Ocean, will 

 some time be found to have contained glacial lakes outflowing southeast- 

 ward to Lake Agassiz. Probably the earliest outlet from the glacial lake 

 of the Peace River was across the watersheds to Lesser Slave Lake and 

 to the North Saskatchewan at its eastward bend, about 50 miles below 

 Edmonton; and the latest outflow from the Athabasca glacial lake appears 

 to have formed a channel across the Mackenzie and Churchill divide near 

 the famous Methy Portage. 



' Descriptive Sketch of the Physical Geography and Geology of the Dominion of Canada, 

 1884, p. 32. 



1 



