Drift in Minneapolis, Minn. — Upliani. 279 
The preglacial course of the Mississippi is thought by Win- 
chelP^ to have reached from near the mouth of Rice creek, 
above AlinneapoHs, southeasterly by Long lake and lakes 
Johanna and Josephine to McCarron lake and the most north- 
ern part of the bend of the present IMississippi in St. Paul. 
From that channel, now deeply enveloped by drift, Winchell 
thinks the river to have been turned when the country was 
uncovered from the Kansan glaciation, taking tlien its inter- 
glacial course through Minneapolis. Later, with the uncover- 
ing of the land after the lowan and Wisconsin stages of gla- 
ciation, the river again took a new course, as at present, across 
this city area.t During interglacial as well as postglacial time, 
its waterfall descending from the hard Trenton limestone 
gradually cut a gorge backward, from south to north; and 
from the lengths of these gorges, in comparison with the re- 
cent rate of retreat of St. Anthony's falls, Prof. Winchell es- 
timates the interglacial stage here to have measured about 15.- 
000 years, and the postglacial period about 8,000 years. 
Another interesting study of postglacial gorge erosion 
within the limits of Minneapolis is by Dr. U. S. Grant,t relat- 
ing to the channel of Minnehaha creek below its falls, and 
especially to a deserted gorge and former waterfall of a part of 
the Mississippi river, flowing west of a higher tract which was 
an island, immediately north of the mouth of this creek. The 
southern part of the old island is the site of the ^Minnesota Sol- 
diers' Home; and the deserted river course and gorge are 
noteworthy features of Minnehaha park. 
Glacial Stri^. 
The directions of the latest glaciation upon the Trenton 
limestone in Minneapolis, as noted from striae in several locali- 
ties by Prof. W^inchell, Prof. C. L. Herrick, and the present 
writer, are as follows, with reference to the astronomic meri- 
dian. 
At forniLT quarry on west side of the river, close south of the 
falls of St. Anthony S . S . PL . 
*Paper last cited. 
fN. H. Winchell, reports on Hennepin county, before cited; Quart. 
Jour. Geol. Soc, London, vol. xxxiv, 1878, pp. 886-qoi, with plan of the 
Mississip])i river at St. Anthony's falls. 
J.A.M. Geologist, vol. vi, pp. 1-6, with map and sections, July, 1890. 
