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Bohling, Geoffrey C. / A ground penetrating radar study of water table elevation in a portion of Wisconsin's central sand plain
[DNR-050] (1988)

II. Geology and hydrogeology of the study area,   pp. 10-18 PDF (1.9 MB)


Page 11

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residuum is considered to be the impermeable base of the glacial outwash
aquifer.
Kraft's detailed borings in the study area (Kraft, in preparation)
seem to contradict the information shown in Clayton's study. Kraft's map
of the elevation of the top of the Precambrian (actually the top of the
clayey residuum) shows a topographic high of 1015 feet above sea level at
observation well number 125, in the eastern third of the study area. From
this high point, Kraft shows the Precambrian surface sloping away to the
south, west and northwest. A value of 978 feet above sea level is recorded
at observation well number 123 (Figure 2).
In addition, Kraft shows a pronounced slope in the Precambrian
bedrock surface northwest from observation well 125, with an elevation of
955 feet above sea level recorded near observation well number 104 (Figure
2), next to the river bluff. Kraft reports that sandstone occurs between
the Precambrian surface and the outwash sand in the area north of High-
way 54, possibly coinciding with the area of steep dip in the Precambrian
surface. Kraft also reports that the sandstone did not offer a great deal of
resistance to drilling and that samples of it consisted of loose grains. It is
impossible to determine the degree of cementation of the sandstone, how-
ever, since the samples were obtained during augering. Therefore, it is
difficult to estimate the magnitude of the permeability contrast between
the sandstone and the glacial sediments. The elevation of the top of the


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