Historical:Dix Limestone Member
M. E. Hopkins and J. A. Simon
The Dix Limestone Member of the Mattoon Formation (Bradbury, 1965, p. 4) is named for Dix, Jefferson County, where it has been quarried locally.
The type section consists of exposures on a southwest-flowing tributary to Casey Fork, about 2 miles south of Dix (NW SE NW 25, 1S-2E).
The Dix may correlate with the fresh-water limestone found at the base of the underclay below the Opdyke Coal.
It lies about 50 feet above the position of the Millersville Limestone and 300 feet above the Shoal Creek Limestone.
In the area of the type section, the Dix is a brownish gray argillaceous limestone as much as 6 feet thick that contains only Spirorbis and numerous ostracodes.
BRADBURY, J. C., 1965, Limestone resources of Jefferson and Marion Counties, Illinois: Illinois State Geological Survey Industrial Minerals Note 23, 15 p.
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