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Anderson, A. C. (Alfred Conrad), 1887-, et al. / Soil survey of Manitowoc County, Wisconsin
(1931)
Soils, pp. 8-28
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Page 8
BUREAU OF CHEMISTRY AND SOILS, 1926 SOILS The upland soils of Manitowoc County are classed with the gray- brown soils of the forested part of the humid region south of the Great Lakes. They developed under conditions of climate and surface features which favored the growth of forests. Light-colored surface soils developed in the forests and dark-colored surface soils on prairie areas in this same general region. There are areas of dark-colored soils in this county, but the dark color was caused primarily by poor drainage rather than by a grass vegetation. With the exception of small areas of open marsh, the whole county was forested before the region was settled by white men. The most striking feature of the soils of the county is that the predominant soils are heavy or fine textured. The county lies within what is usually known as the red-clay section of Wisconsin. The soils of the county naturally fall into two major classes, the well-drained, normally developed or mature soils, and the immature soils. The first group includes soils of the well-drained uplands derived from glacial till and soils of the better-drained areas on old glacial- lake and alluvial terraces. In this region the normally developed or mature soils are weath- ered to a depth of 3 or more feet, depending on the surface relief and composition of the parent materials. The most typical mature soils in the county developed from glacial- till parent material. These soils are characterized by a consistent profile which shows a grayish-brown friable surface soil, a rather heavy light-brown or reddish gravelly clay subsoil, and a light- brown or reddish-brown glacial-till substratum, which is the parent material. The surface soil includes the friable comparatively light-textured upper layers from which much of the clay material including the inorganic colloids has been removed. The subsoil is the rather heavy layer where much clay material, including colloids, has been depos- ited by percolating water in the course of weathering. This horizon has a coarsely granular structure and is neutral or slightly acid in reaction. The third main layer or horizon is the parent material, the unweathered or only slightly weathered material from which the soil has developed. This horizon has no regular structure. It contains sufficient lime to effervesce freely with hydrochloric acid. The parent soil material consists largely of two very different kinds of glacial till, the older brown till and the more recently deposited so-called red till which overlies the brown till. Extensive areas of soil materials on glacial terraces and flood plains are from the same original sources but have been reworked and redeposited by water. The brown till is usually considered to have been formed by the grinding up of the underlying dolomite bedrock, with some admix- ture from the crystalline rocks to the north. The red till is usually considered to be partly composed of rock debris and partly of glacial lake sediments carried southward from the Lake Superior region.' 8 ALDN, W. C. QUATERNARY GEOLOGY OF SOUTHEASTERN WISCONSIN, WITH A CHAPTER ON THE OLDER ROCK FORMATIONS. U. S. Geol. Survey Prof. Paper 106, 356 p., illus. 1918. 8
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