400 
GLACIAL DRIFTS IN MINNESOTA 
local Keweenawan volcanics and in part also of red sandstone 
pebbles. Clays were also scooped up from the Lake basin, so that 
in some places the drift is stoneless, or nearly so. The drift not 
only varies from very stony till to stoneless drift, but the moraines 
in part coincide and in part are discordant with those of the Pa¬ 
trician drift which it overrode. As it is, its whole work appears 
somewhat capricious; and in this, it is not so very different from 
the Illinoian drift that is seen in Minnesota. A person may easily 
imagine that when the Superior drift-sheet over-lying the Patrician 
drift becomes as old as the Illinoian drift now is, erosion will 
have reduced it to stony hills and gravel knolls on a bed-rock 
plain. 
During the retreat from northern Minnesota, the Patrician 
glacier was apparently shut in between the Labradorian and the 
Kewatin glaciers, the three coming into contact along their sides. 
The Labradorian glacier then had its maximum extension west, 
and the Kewatin glacier its maximum south, as shown on plate 
XXXV. As these two glaciers began to retreat, or recede, by melt¬ 
ing off, the Patrician glacier receded farther also. All three of 
the glaciers made many re-advance moraines, or “recessional mo¬ 
raines,” and it was, of course, in one of its re-advances that the 
Patrician glacier met the others as described. In a later re-advance 
of the Kewatin glacier, it pushed beyond its first maximum line 
in northern Minnesota in part and sent a sublobe in front of the 
Patrician glacier’s position, depositing a thin drift-sheet over that 
of the latter and lapping onto that of the Labradorian a little 
(see plate xxxvi). 
This last glacier of all in Minnesota affords the greatest variety 
for the study of drift phenomena. The normal ground-moraine 
is a till with smaller and more boulders than the Kansan Kewatin 
shows. The moraines are, further, decidedly more bouldery than 
the known Kansan appears to be in any case. Outwash gravels 
formed, during the recessions in, or in front of, the moraines, into 
many and large plains, and some of these were again over-ridden 
by ground-moraine, or thrust up by end-moraine structure. Thus 
the deposit of a clay-till, nearly like that of the Kansan drift was 
made so gently that an old soil, or peat-bed under it, was not 
destroyed. The grinding of till and an underlying gravel into a 
