The subsection coincides with the basin of Glacial Lake Superior in Minnesota, as defined by the Minnesota Soil Atlas (University of Minnesota, 1977). The subsection covers a very small area in Minnesota, but is part of a larger unit in Wisconsin.This subsection occupies a glacial lake bed and consists of a relatively narrow band of lacustrine clays located along the south and west shore of Lake Superior. Topography is level to gently rolling, except along rivers and streams. Water has cut significantly deep valleys throughout the region and red clayey sediments are deposited into Lake Superior. Presettlement vegetation consisted of forests dominated by white spruce, white pine, and aspen-birch. Land uses include agriculture, recreation, and forestry.
Landform
A glacial lake plain covers almost all of the subsection (Hobbs and Goebel 1982, Farrand 1982). It is about 400 feet above the present level of Lake Superior. There are some small, isolated areas of end moraine associated with the Highland Moraine to the north. The plain is deeply dissected by numerous rivers and small streams.Bedrock geology
Thickness of glacial drift over bedrock ranges from 50 to 100 feet. Bedrock is not exposed at the surface except in localized outcrops along streams. Bedrock consists of Precambrian (Middle Proterozoic) sedimentary bedrock, primarily feldspathic to quartzose sandstone and shale, and including lithic sandstone and siltstone (Morey et al. 1982). The shale is locally copper-rich (Dorr and Eschman 1984).
