124 N. H. WINCHELL — GLACIAL LAKES OF MINNESOTA 



The limits of the lake there formed are not known. This lake is hypo- 

 thetically represented on the map. In its lower stages it may have been 

 much enlarged, and its outlet may have been toward the west, into the 

 Red river of the North, through lake Thompson. When it was perma- 

 nently connected with the Mississippi its elevation was about 18,000 feet, 

 lake Winnibigoshish being now 1,290 feet. If its waters ever passed 

 through the abandoned channel mentioned, in Polk county, its eleva- 

 tion must have been lowered to about 1,225 feet. 



21. Lake Upham* 



When the northwestern edge of the lake Superior ice-lobe crossed the 

 valley of the Saint Louis river, that river was ponded back and produced, 

 as already explained, two glacial lakes — lakes Saint Louis and Nemadji — 

 and its water was turned to the Mississippi. Those lakes were respect- 

 ively 1,135 and 1,070 feet above the sea. But prior to those lakes the 

 Lake Superior ice-lobe had thrust its margin still farther northwestward, 

 and had dammed back the Saint Louis at a higher level, forming lake 

 Upham,t at 1,300 feet above the sea, which had its outlet into the Mis- 

 sissippi through a channel not well known, but undoubtedly across the 

 low divide which separates the waters of East Savanne river from those 

 of West Savanne river, in the northeastern part of Aitkin county. This 

 passage across the divide was long used by the early fur traders in travel- 

 ing by canoe from the upper Mississippi to lake Superior. The actual 

 channel has not been discovered, and there are good reasons for locating 

 it near the ice-border, farther south. In case it was along this ice-border 

 the lake must have had an unsteady surface level, and the water prob- 

 abl}' passed to the Mississippi through the valle}' of Prairie river. There- 

 must have been instances in which the river trenched on the ice, and 

 that may have formed the kame which is known to exist on the portage 

 line from the Saint Louis river to Prairie lake'j in township 50, range 20. 



Lake Upham was a large body of water, and extended from near the 

 Mississippi, in Itasca county, to beyond the center of Saint Louis county. 

 The region which it covered is still poorly drained, and is covered largely 

 b}^ an extensive peat bog. In general, it occupies the triangular area 

 between the gabbro highlands on the south, on which the southern 

 moraine is piled, and the Giants range of granite on the north, on which 



* This lake was named from Mr Warren Upham, whose assiduity and long labor brought to light 

 most of the features of the drift of Minnesota. 



fThis lake was briefly described and named in vol. vi of the Final Report of tlie Geological 

 Survey of Minnesota, Atlas, plate 66. 



X This very significant kame \vas noted in the Ninth Annual Report of the Minnesota Geological 

 Survey, p. Un. 



