Huron, N. D., where there is a col and a constriction in the James river, 
a preglacial divide, over which the reversed headwaters of that stream now 
run southward. From Huron eastward its location is a matter of specula- 
tion backed up with slender evidence. From here it may have turned south 
across the present Mississippi valley somewhere near ‘military ridge,” as 
Hershey (46) would have it, and then eastward, or it may have turned 
north some distance east of Huron along the east edge of the basin of the 
Red river, but this will be discussed more fully later. “Between the Rock 
river drainage line and Lake Michigan there is a somewhat less elevated 
belt of limestone, which ‘extends curvingly in a direction east of south 
into western Indiana.” (Leverett, 64:16.) Somewhere in eastern Illinois 
or western Indiana a spur ran south, probably near the present divide be- 
tween the Wabash and Illinois system separating the preglacial as well as 
the present basins. The location of the divide north through Wisconsin is 
not well known, but there is no doubt that it was east of the present “drift- 
less area.” 
Even if it were possible and profitable, space does not admit of a de- 
tailed discussion of secondary divides, which can generally be inferred 
from the location of the preglacial valleys. After calling attention to the 
fact that the present Mississippi river has evidently a system of drainage 
widely different from the system or systems which were operative in pre- 
glacial times within the region now drained by it, Leverett says: ‘Besides 
opening a new channel at each of the rapids, the stream apparently is occu- 
pying sections of two or more independent preglacial valleys.” (64 :461.) 
As to the course of the Mississippi above St. Paul, Chamberlain sug- 
gested, in 1879, that it is post-glacial (19:255), but that it probably follows 
the preglacial channel in short stretches. Hershey, in 1897, agrees with the 
suggestion. 
Hershey has the following to say concerning the preglacial valley 
above St. Paul: “The high upland area which trends north and south on 
its eastern side at some distance from its immediate border, continues 
without a change for many miles to the north, passing to the east of 
Lake Phalen. Although deeply covered with drift, it is undoubtedly based 
on an upland area of rock. To the west of it, and in the direct line of con- 
tinuation of the old Mississippi valley, there is a topographical depression 
which trends for many miles te the northwest. It is occupied in places by 
lakes, the most important of which is lake Phalen. This, in my opinion, 
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