254 THE GLACIAL LAKE AGASSIZ. 



wlieu these remaius were deposited.^ Even at the present time much of 

 the area of stratified clay that ahnost continuous!)' forms the central part 

 of the valley plain is covered by the highest floods, and probably no por- 

 tion of it is more than 10 feet above the high-water line of the Red River 

 and its tributaries. The position of the thick beds of fine silt and clay in 

 the central depression of the Red River Valley shoAvs that they were not 

 mainly deposited by the waters of Lake Agassiz, which must have spread 

 them somewhat equally over both the lower and higher parts of the lacus- 

 trine area, but instead appears to prove that at least their upper and greater 

 part was brought by the rivers which flowed into this hollow and along it 

 northward after the glacial lake was withdrawn. 



ASSOCIATED GLACIAL LAKES. 



The review of the history of Lake Agassiz will be completed by bring- 

 ing into comparison with it the contemporaneous formation of great glacial 

 lakes on the northern borders of the United States and the adjoining south- 

 ern edge of Canada, and in its northwestern interior, from the city of Quebec 

 on the east to the elbows of the South and North Saskatchewan rivers and 

 to the head streams of the Mackenzie on the west. The glacially dammed 

 Laurentian lakes, and a very large extension of Lake Ontario or Iroquois, 

 and the later glacial Lake St. Lawrence, east to Quebec, northwest in the 

 Ottawa Valley, and south in the basin of Lake Champlain and the Hudson 

 Valley, were quite probabl}-, as before noticed, portions of the avenues of 

 outflow from Lake Agassiz after it had fallen below the Lake Traverse out- 

 let and before Hudson and James bays were so far uncovered from the 

 ice-sheet as to be occupied by the sea and receive the northeastward out- 

 flow of the Winnipeg and Saskatchewan basin. In Minnesota and South 

 and North Dakota prophecies .of Lake Agassiz had been given by the earKer 

 glacial lake of the area now drained by the Blue Earth and Minnesota 

 rivers, which may be named Lake Minnesota, and by a long and narrow 

 contemporaneous lake in the James River Valley, which Prof. J. E. Todd 



'Geology of Minnesota, Vol. II, pp. 529, 530, 663, 664, 668, and 669. See notes of wells, Chapter 

 X, in McCanleyville, Wilkin County; Glynrton, Clay County; and Andover, Polk County, Minn.; and 

 in Johnstown, Grand Forks County, and near Grafton, Walsh Cmmty, N. Dak. 



