142 THE GLACIAL LAKE AGASSIZ. 



withdrawn to Wacouia, in Carver County, where it again haked, forming 

 its sixth or Waconia moraine. This records the position of the front of 

 the ice-sheet immediately before its continued recession gave place for the 

 beginning of Lake Agassiz. It will therefore be described somewhat in 

 detail along its course adjacent to this glacial lake. 



SIXTH OR WACOXIA MORAINE. 



Between the fifth and sixth moraines the southeast end of the Minne- 

 sota ice-lobe retreated from Elysian to Waconia, a distance of about 40 

 miles from south to north, uncovering the lower portion of the Minnesota 

 Valley and finally draining the glacial lake of the Blue Earth and Minne- 

 sota basins, which had outflowed southward in its highest, early stages by 

 Union Slough in loAva to the East Des Moines River, and later to the east 

 by the Cannon River. The advance of the east side of this ice-lobe at the 

 time of the Kiester and Elysian moraines beyond its pre'saous limit, by an 

 incursion from Wright County to Chisago County and the edge of Wiscon- 

 sin, had been followed bv a withdrawal from the greater part of the area 

 thus acquu-ed, until at the time of the sixth moraine the most eastern por- 

 tion of the ice margin was accumulating the prominent drift hills close east 

 and north of Elk River, in Sherburne County. The glacial recession there 

 from east to west and southwest between the Elysian and "V^'aconia moraines 

 appears to have been also about 40 miles. A long indentation of the ice- 

 sheet, between its Minnesota and Lake Superior lobes, was melted back 

 during the same interval, the apex of this reentrant angle being can-ied 

 from southeastern Stearns County 50 miles west to Lake Whipple and 

 Glenwood, in Pope County. But in some places the ice border north and 

 east of Waconia had probably retreated no more than a few miles, and on 

 the southwest side of the Minnesota lobe, in Redwood, Yellow Medicine, 

 Chippewa, Swift, and Big Stone counties, there was only slight recession of 

 the ice, and the Elysian and Waconia moraines seem to be blended, though 

 they form together only inconspicuous marginal deposits.^ 



' Geology of Minnesota, Vol. II, pp. 642, 625, 440, 463, 464, 487, 488, 233, 415, 105, 106 [Waconia], 128 

 166, 213, 516; Vol. I, pp. 606, 621. (These citations are iu the order from east to west for the areas sev- 

 erally described iu the chapters of the Minnesota reports treating of separate counties. 1 



