Historical:Allard Limestone Member
Elwood Atherton, Charles Collinson, and Jerry A. Lineback
The Allard Limestone Member of the Menard Formation (Swann, 1963, p. 38-40) is named for Allard College School, Johnson County.
The Allard Limestone Member is located 2.2 miles southwest of Allard College School, Johnson County, in a cut at the south end of the Illinois Central Railroad tunnel (SW NW NE 1, 13S-4E).
Extent and Thickness
The Allard ranges from a little more than 30 feet in the far south to 10-12 feet in much of the northern area of the Menard.
The Allard Member is dominantly limestone.
SWANN, D. H., 1963, Classification of Genevievian and Chesterian (Late Mississippian) rocks of Illinois: Illinois State Geological Survey Report of Investigations 216, 91 p.
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