596 THE GLACIAL LAKE AGASSIZ. 



At the time wlaeu tlie last ice-sheet retreated, however, the confluent 

 waters of Devils and Stump lakes were raised to a shore-line which now 

 has a slight ascent from west to east, lying 21 to 25 feet above the low 

 stage of Devils Lake in 1889. This shore is traceable around both lakes, 

 passing above the watershed that now divides them. At the same height, 

 as shown by leveling, a well-marked watercourse is found running across 

 the present watershed between the west part of Stump Lake and the Shey- 

 enne River, in section 19, township 151, range 61. This glacial channel of 

 outflow has a nearly flat bottom 150 feet Avide, and is bordered on both 

 sides by moderately steep morainic hills 50 to 75 feet high. 



While the ice border was retreating across these lake basins the inflow 

 from its melting produced a large outflowing stream, but there is no proof 

 that any time since the departure of the ice has been so humid as to raise 

 the lakes to this channel. The heavy growth of timber which in many 

 places borders the lakes extends across the highest beach ridge or line of 

 erosion to the next shore, which, as before noted, is the limit of the forest, 

 and therefore is believed to have been the lake margin since the beginning 

 of this century. Though the climate so lately had during a considerable 

 term of years more rainfall than now, it was yet sm'ely less than the aver- 

 age amount in the region of the Laurentiau lakes and in New England, 

 else the levels of both lakes must have been raised to overflowing — that 

 is, to the continuous liighest shore-line and channel of discharge southwest 

 of Stump Lake. 



The following are notes of the elevations of these lakes, of their former 

 shore-lines above their present levels, and of this outlet. A slight differen- 

 tial uplifting, like that which gave to the beaches of Lake Agassiz their 

 northward and eastward ascents, is shown by the glacial shore-line, which 

 is now level through its western 1 8 miles from Minnewaukan to the city of 

 Devils Lake, but thence rises eastward about 3 feet in a distance of 16 

 miles to Jerusalem, and 1 foot more in the next 6 miles southeast to the 

 channel of outlet. 



