The surface of Champaign County, as a general thing, is composed of black prairie soil, from one to five feet in thickness. This prairie soil is under-laid by a yellow clay subsoil. Below this clay subsoil occur alternate beds of clay, gravel and quicksand of the drift formation to the depth of from 120 to 250 feet, below which there are other alternations of shale, slate, soapstone and limestone, with one or more beds of coal. Much of the loose materials found above the rocky beds of Champaign County are composed of what is called “drift,” which consists of clay, sand, rounded and water-worn masses of granite and porphyry, together with the red sandstone of the Lake Superior region, all of which have been swept southward from their native beds with a force sufficient to obliterate the angles from the hardest fragments; and these have been rudely intermingled with the surface materials of the formations over which they were transported. This drift, as it was deposited, filled up the beds of the ancient valleys and covered much of the remaining surface to a greater or lesser depth. The transportation of this “drift” for such a long distance is probably due to the slow but powerful movement of immense glaciers from the frozen regions of the north, in the same manner as the glaciers of the mountain regions of Europe are now slowly melting and sliding and dragging with them huge masses of mountain rock, wrenched off with Titantic force by the departing ice.
Clay and sand are the only elements underlying the Champaign prairie-sod that can be used for building purposes. Of the clay, a fair quality of brick and drain tile are being made in several places. The fire-clay, soapstone and limestone are covered too deeply with “drift” to admit of their being economically brought to the surface. Our chief sources of building stone and lime must continue to be the quarries of Kankakee.
Source: A Standard History of Champaign County, Illinois, by J. R. Stewart, published by The Lewis Publishing Company, Chicago And New York, 1918.