398 
GLACIAL DRIFTS IN MINNESOTA 
been successful in Minnesota. The Iowan drift is in theory a 
product of an Iowan Kewatin glacier that developed parallel to the 
three known Kewatin glaciers that crossed Minnesota into Iowa. 
In theory, from the Minnesota angle, an Iowan Kewatin glacier 
as late as, or later than, the Illinoian glacier, would have crossed 
the boulder-strewn, gravel-terraced, eroded hills and valleys of the 
old Kansan drift. The more lightly and shorter its glaciation, the 
more stony and gravelly its work would be expected to be, and 
thus much like the Wisconsin stage in Minnesota. As described by 
geologists, the Iowan drift in Iowa is very like the Kansan till. 
As compared to the glaciation in Wisconsin state, the glaciers 
of the Wisconsin stage in Minnesota are supposed to have come 
in the middle and later parts. A glacial tongue from each of the 
two main centres of snow-gathering and ice-radiation, Labrador 
and Kewatin, reached Minnesota, and a third glacier came from 
an intermediate centre — Patricia. The three are so nearly con¬ 
temporaneous that soil, peat, trees, etc., do not mark their sur¬ 
faces where the drift of the one lies over that of another. 
The Patrician glacier came in first. On the map, plate xxxiv, 
the full extent of the Patrician glacier is shown; and on plate 
XXXV it is shown in retreatal stage, with the glaciers that followed 
it. It came in from and retreated to the region north of Lake 
Superior, and up there, even in the northeast point of Minnesota, 
it left little trace except bare bed-rock. At its gathering ground 
it had hard crystalline rocks to work on, but to the south, as at 
Hinckley, it began to show some admixture of Manitoba lime¬ 
stones as if from the Kansan drift, parts of which the glacier 
seems to have plowed up. At Minneapolis (No. 14) sandstone 
and limestone from the local stratified rocks appear abundantly 
in Patrician drift. From a very bouldery and pebbly drift to the 
north it changes southward to greater content of rock-flour and 
clay, but never ceases to be stony and sandy. Plowed fields of 
the “red” clay soil do not rain-wash as do those of the “gray” 
soil. 
The Patrician glacier built great, rough, terminal moraines, 
bouldery ground-moraine, and many high outwash plains. At Pine 
Bend, below Saint Paul, the moraines blockaded the old valley of 
the River with two to three hundred feet of till and from there 
