Historical:Spring Grove Member
Charles Collinson and Elwood Atherton
The Spring Grove Member of the Wapsipinicon Limestone is named for Spring Grove Township, Linn County, Iowa.
The type section of the Spring Grove Member is located on the right bank of the Wapsipinicon River (cen. 24, 86N-7W) near Spring Grove Township, Linn County, Iowa.
Extent and Thickness
The Spring Grove Member is probably as much as 25 feet thick in subsurface, but it is only 5-10 feet thick in the outcrop area, where it is exposed in the quarries at Milan and Rock Island.
The Spring Grove Member of the Wapsipinicon Limestone (Stainbrook, 1935, p. 251-252) formerly was the upper part of the Kenwood. The Spring Grove Member is brown laminated dolomite and dolomitic limestone that weathers into thin plates.
The Spring Grove Member is non-fossiliferous.
STAINBROOK, M. A., 1935, Stratigraphy of the Devonian System of the Upper Mississippi Valley: Kansas Geological Society Guidebook, 9th Annual Field Conference, p. 248-260.
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