Historical:Mulberry Grove Silt Member
H. B. Willman and John C. Frye
The Mulberry Grove Silt Member of the Glasford Formation was informally named the Mulberry Grove silt by Jacobs and Lineback (1969, p. 12) in the south-central Illinois region. It was named for Mulberry Grove, Bond County.
The type locality is the Mulberry Grove Section (Jacobs and Lineback, 1969, p. 21) in borrow pits just east of Mulberry Grove along Interstate Highway 70, SW SW Sec. 31, T. 6 N., R. 1 W., Fayette County.
The Mulberry Grove Member is overlain by the Vandalia Till and underlain by the Smithboro Till Member. It appears to occur at approximately the same stratigraphic position as the Duncan Mills Member of central western Illinois.
Extent and thickness
The unit is generally less than 1.5 feet thick.
It is a thin, lenticular unit consisting mostly of calcareous silt, and locally contains a few fossil snail shells and lenses of sand and gravel.
Age and correlation
The Mulberry Grove Silt probably is within the early part of the Monican Substage of the Illinoian Stage.
JACOBS, A. M., and J. A. LINEBACK, 1969, Glacial geology of the Vandalia, Illinois, region: Illinois State Geological Survey Circular 442, 24 p.
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