1876.) Plain, Prairie, and Forest. 659 
selves are sometimes quite heavily timbered, but frequently 
treeless and covered with grass, and then known as “ bottom 
prairies.” In Illinois, of which State perhaps three quarters to 
two thirds are prairie, the wooded tracts are almost entirely in 
the river valleys or along the edges of the bluffs; the uplands, 
or rolling and nearly flat plains between the streams, are, to a 
large extent, destitute of timber. Very much the same condition 
of things exists in Iowa. Here, however, a considerable portion 
of the surface east of a line drawn in a northwesterly direction 
from the mouth of the Makoqueta River to the state line is 
pretty well timbered, while west of this there is a gradually in- 
creasing deficiency as we go towards the Missouri. All through 
the State, however, except in the northwest corner, there are 
isolated patches of timber on the upland, often forming beautiful 
and extensive areas of woodland. In Wisconsin the prairie re- 
gion lies mostly to the north of the river of that name. Just 
along the river is a narrow belt of prairie, in interrupted patches. 
Then, twelve or fifteen miles farther south, comes an extensive 
and continuous prairie, stretching along from east to west and oc- 
cupying the divide between the waters flowing into the Wisconsin 
and those tributary to Rock River. It was on this line of prairie 
that the famous “ military road” was built by the government 
to connect Lake Michigan with the Mississippi, and which was 
once of so much importance. South from this east and west 
line of prairie run several broad patches of the same, gradually 
Widening southwards, and occupying more than half the surface 
when we reach the Illinois state line. In the midst of these 
areas of prairie are fine groves of timber, quite dense, sometimes 
near a creek and sometimes far away from water. In the bend 
between the Wisconsin and the Mississippi, as the latter curves 
to the east just before passing Cassville, there is a beautiful, 
isolated prairie, about fourteen miles long and twelve wide in 
lts widest part, having one large grove near its southeastern 
i : Space is wanting to enable us to indicate all the peculiar- 
ities of the distribution and intermingling of prairie and timber 
3 from Minnesota to Arkansas; but the reader must surely have 
beome convinced that inequality in the distribution of moisture 
_ SHers no solution of the problem before us. — 
_ Let us turn, at present, to the geological side of the investiga- 
_ tion. The whole of New England and New York, and a large 
Part of Ohio and Indiana, together with the whole of Michigan 
and of Northern Wisconsin, constitute a region over which the 
