T. C. Buschbach
The Charter Member of the Mt. Simon Sandstone (Templeton, 1950, p. 156), the uppermost member, is named for Charter Oak School, De Kalb County.
The type section of the Charter Member of the Mt. Simon Sandstone is located 3.5 miles south of Charter Oak School, DeKalb County. It is the interval from 1381-1648 feet deep (sample set 1466) in the same boring as the Lacey Member.
Extent and Thickness
The Charter Member is 145-320 feet thick.
It is medium- to fine-grained, partly conglomeratic sandstone with some red micaceous shale at or near the base.
TEMPLETON, J. S., 1950, Mt. Simon Sandstone in northern Illinois: Illinois Academy of Science Transactions, v. 43, p. 151-159.
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