190 The American Geologist. March, i89i 
cast part of Yellow Medicine county, Minn. Daring its next 
stage of retreat this ice-lobe* was melted away from the whole of 
Le Sueur county, and its southeast extremity was withdrawn to 
Waconia in Carver county, where it again halted, forming its sixth 
or Waconia moraine. The seventh or Dovre moraine marks a 
pause in its recession when its southeast end rested on Kandiyohi 
county. Probably nearly all of the southern half of Minnesota 
was at this time divested of its ice-mantle, while nearly all of the 
northern half was still ice-covered. By its next recessions the 
glacial border was withdrawn to the eighth or Fergus Falls mo- 
raine, and the ninth or Leaf Hills moraine. These are merged 
together in the prominent accumulations of the Leaf Hills, which 
lie in southern Otter Tail county, Minnesota, reaching in a semi- 
circle from Fergus Falls to the southeast, east, and northeast, a 
distance of about fifty miles, and marking the southern limits of 
this ice-lobe when it terminated half-way between the south and 
north borders of Minnesota.* The south part of lake Agassiz 
probably began to be uncovered by the retreating ice-sheet between 
its stages marked by the Waconia and Dovre moraines ; and this 
lake reached northward from lake Traverse 100 to 125 miles along 
the Red River valley when the Fergus Falls and Leaf Hills mo- 
raines were accumulated. 
On the west side of lake Agassiz the Dakota lobe of the ice- 
sheet, from its junction with the Minnesota lobe near the head of 
the Coteau des Prairies, twenty-five miles w r est of lake Traverse 
and Brown's valley, at first reached about 200 miles south along 
the valley of the James or Dakota river to Yankton and the Mis- 
souri ; but it w T as gradually diminished in its extent until, at the 
times of formation of the Kiester, Elysian, Waconia, and Dovre 
moraines, it no longer retained its lobate outline. While these 
moraines were being formed in Minnesota, the southwestern bound- 
ary of the ice-sheet in South and North Dakota passed from the 
vicinity of Big Stone lake and lake Traverse northwesterly along 
moraine belts that have been traced through Sargent, Ransom, 
Barnes, and Griggs counties, North Dakota, and by the sources of 
the James and Sideline rivers. During the later stages repre- 
sented by the Fergus Falls and Leaf Hills moraines, the Dakota 
* For detailed descriptions of these moraines, and of the recession of 
The ice sheet in this state, see Geology of Minnesota, vols, i and ii. 
