. ees a “we Bape . . 5 ee a. x es ~~ 
of Wisconsin and part of Iowa.’ ee 11 
ices The third — of the report is devoted toa description of 
-» © the formations of the interior . the Chippewa Land District. In 
ie our notice of it we must be brief. 
we: The protozoie strata which en been described as forming the 
. Seetions on the ississippi, extend on the east’side of the Missis- 
sippt for an average distance in a direct line into the interior of fifty 
_ to seventy-five miles; that is, to the falls of the principal eastern 
tributaries of that river. Here the crystalline rocks first appear 
above the water courses forming low falls and rapids. ‘These igne- 
ous ranges do not rise abruptly in this part of the United States into 
_ elevated mouutains; on the contrary they are seldom seen except 
in the immediate cuts of the streams, being covered for the most — + 
part with drift. The character of the country generally towards = 
~_ the summit Jevels leading to Lake Superior, is a succession of 
terracés of moderate elevation, chiefly composed of drift, often 
having a nucleus no doubt of granite, syenite or hornblende rocks ; 
but. these: protrude only occasionally. At intervals the stre reams 
are ruffled into rapids, being filled with boulders which obstruct 
materially their navigation. A portion of these boulders may 
have been transported from great distances; the greater part how- 
€ver appear to be not far removed from the e parent rock. 
__ It is matter of surprise that so large an area of the interior of ° 
this district, and indeed of the sources ; of the Mississippi generally, 
should be level tamarack and cedar swamps, since in approaching 
& great water shed that gives rise to one of the largest rivers in 
the world, one is led to ere a country with physical features 
' of quite a different characte 
' _ Interposed between the susie and igneous rocks of the 
__. Interior of the district and the lowest sadstones, some green and 
-- red schistose beds have been observed at different localities. 
hese appear to have been derived from the decomposition and 
detritus of the more easily decomposing felspathic granites. 
The lower beds of sandstone adjacent to the igneous outburst, 
- are not unfrequently changed to a hard quartzite. The red pipe- 
stone so highly prized by the northern tribes of Indians, is found 
a also near the junctions of these formations, associated with 
rtzite. 
y 
ne tose 
ay. : 
a. te other. Over a large portion of this area the solid rocky beds. 
are covered by comparatively recent deposits of drift sand, ted ee 
