228 MAN AND THE GLACIAL PERIOD. 



of the United States,* one can readily see the relation of 

 the valley between Lake Traverse and Big Stone Lake to 

 an area marked as the bed of what is called Lake Agassiz. 

 During the Glacial period Brown's Valley, the depression 

 joining these two lakes, was the outlet of an immense body 

 of water to the north, whose natural drainage was towards 

 Hudson Bay or the Arctic Ocean, but which was cut off, 

 by the advancing ice, from access to the ocean-level in 

 that direction, and was compelled to seek an exit to the 

 south. 



Thus for a long period the present Minnesota River 

 Valley was occupied by a stream of enormous dimensions, 

 and this accounts for the great size of the trough — the 

 present Minnesota being but an insignificant stream wind- 

 ing about in this deserted channel of the old " Father of 

 Waters," and having as much room as a child of tender 

 age would have in his parent's cast-off garments. This 

 glacial stream has been fittingly named River Warren, 

 after General Warren, who first suggested and proved its 

 existence, and so we have designated it on the accon^any- 

 ing map of Minnesota. 



Lake Traverse is fifteen miles long, and the water is 

 nowhere more than twenty feet deep. Big Stone Lake is 

 twenty-six miles long, and of about the same depth. 

 Brown's Valley, which connects the two, is five miles long, 

 and the lakes are so nearly on a level that during floods 

 the water from Lake Traverse sometimes overflows and 

 runs to the south as well as to the north. 



The trough occupied by these lakes and valley is from 

 one mile to one mile and a half in width and about 120 

 feet in depth. If we had been permitted to stand upon 

 the bluffs overlooking it during the latter part of the 

 Glacial period, we should have seen the whole drainage of 

 the north passing by our feet on its way to the Gulf of 



* See page 66. 



