Champaign County Topography
The topography of the county has been thoroughly delineated by the State Geological and the United States Geological surveys, as well as by experts connected with the University of Illinois, especially by Prof. C. W. Rolfe of the Illinois State Laboratory of Natural History. Based upon such authorities, it is found that the altitudes of the incorporated cities and villages in the county are as follows: Ludlow, 770; Champaign, 741; Rantoul, 756; Urbana, 718; Philo, 737; Tolono, 733; Thomasboro, 731; Fisher, 721; Pesotum, 715; Mahomet, 709; Sadorus, 691; Ivesdale, 679; Longview, 678; St. Joseph, 676; Sidney, 673; Homer, 661.
Action of Glaciers
A consideration of these elevations and others in other portions of the
county indicates a general inclination of the land surface from northwest to
southeast, although, as stated, there is a distinct water-shed which divides the
Wabash system from that of the Illinois and the Mississippi. This general trend
was determined by glacial action, the great ice sheet moving down from the
north, scouring off the land, its successive onward stages being indicated by
ridges or, geologically speaking, moraines, which rise above the surface of the
surrounding country to heights varying from twenty to a hundred feet. The
glaciers which moved across what is now Champaign County were portions of what
have become known as the Bloomington and the Champaign systems, the former,
which plowed across the northeast corner, being bold and aggressive in character
and leaving behind ridges from fifty to a hundred feet high. The streams have
cut these into knolls or hills, creating the most considerable heights in the
county near Ludlow, from 820 to 830 feet above sea level; near Dillsburg, from
810 to 820 feet, and just east of Gilford and Flatville, 820 feet. The second
moraine enters from Piatt County in a series of ridges which join the
Bloomington system when well within Champaign County. The main ridge enters near
Mahomet, is broken by the Sangamon River, its heights ranging from 750 to 670
feet, and after reaching out into the central parts of the county, breaks into
three distinct ridges and passes over into Vermilion County. At Rising, where an
altitude of 810 feet is reached, the large branch which connects the Bloomington
and Champaign systems, is given oft to the northeast. These moraines are the
watersheds of the Wabash and Mississippi basins.
No other single agent has been so potent in the modification of the surface of
the earth as have glaciers and ice sheets; and this statement applies with
particular significance to central Illinois and Champaign County. When it is
remembered that these ice sheets were hundreds and possibly thousands of feet
thick, and were hundreds of miles in width and length, some adequate idea may be
formed of their power to plow up and completely change the surface structure of
the earth.
The debris which they brought from the
Laurential mountains of Canada was distributed over Illinois generally,
greatly to the enrichment of its soils. This material, which eventually became
the wonder-fully productive soil in all the glacial areas, was transported in
several ways. Much of it was pushed along mechanically in front of the advancing
ice-sheet, so that when the forward movement began to be retarded, this material
was left scattered along the edges of the advancing body. Much material was
carried along under the ice-sheet and was ground and distributed over the
glacial area. Other material, again, was carried to the surface of the
ice-sheet, and often deeply imbedded in it. When the movement was finally
checked, the superimposed material becoming heated by the sun, worked its way
through the ice and rested on the ground, the whole body of ice eventually
melting.
Vast quantities of material were also carried by the streams which continually
flowed from the melting ice. Much of the detritus was left on the broad, flat
prairies, but much was carried into the streams which overflowed their banks,
where it was deposited as alluvium.
The material which these glaciers brought into the State of Illinois, as the
basis of her vast material wealth, goes under the general name of Drift. Its
composition varies, but its main constituents are clay, sand and boulders. This
drift is sometimes found stratified, but more generally is without definite
layer formation.
Without going into details as to authorities, it may be stated that, in North
America, there seems to have been three great centers of glacial movement one
known as the Labrador ice sheet; a second called the Kewatin ice sheet, and the
third, the Cordilleran ice sheet. The first sheet had its center of movement
near the central point of the peninsula of Labrador; the second, near the
western shore of Hudson Bay, and the third moved from the Canadian Rockies.
The ice sheet, the center of which rested on the Labrador peninsula, moved
northeast, northwest, south and southwest, the movement in the direction last
named starting a large section of the vast body toward what is now the State of
Illinois. The Labradorean sheet reached its extreme southern limit in southern
Illinois, some 1,600 miles from the point of departure. The advancing front in
Illinois took the form of a gigantic crescent, and its extreme southern reach,
according to the most recent geological surveys, may be traced from Randolph
County southeast, through the southern side of Jackson eastward through southern
Williamson, east and northeast through southeastern Saline, northeastward to the
Wabash through the northwest corner of Gallatin and southeastern White. That
line also marks the southern limit of the prairie areas, and is coincident with
the northern foothills of the Ozark Mountains, which trend east and west across
the State through Union, Johnson, Pope and Hardin.
According to the more recent investigations, Illinois was subject to at least
four ice-sheet invasions. In the order of time, these were (a) the Illinois
sheet, which covered nearly the entire State; (b) the lowan sheet, moving over
the area bounded by the Rock River on the west, Wisconsin on the north, Lake
Michigan on the east, and on the south by a parallel extended from the southerly
bend of that body of water; (c) the Earlier Wisconsin, covering the northeastern
fourth of Illinois, and (d) the Later Wisconsin, plowing out the western borders
of Lake Michigan and extending some fifty or sixty miles westward. The Illinois
ice-sheet is the one, obviously, which included Champaign County in its
operations. The details of its work, in this more limited area, have already
been given.
Source: A Standard History of Champaign County, Illinois, by J. R. Stewart, published by The Lewis Publishing Company, Chicago And New York, 1918.