Historical:Brereton Limestone Member
M. E. Hopkins and J. A. Simon
The Brereton Limestone Member of the Carbondale Formation (Savage, 1927, p. 309, 313-315) is named for Brereton, Fulton County.
The type section is along the east bank of Middle Copperas Creek (SE NE 1, 7N-4E) (Wanless, 1956, p. 10; 1957, p. 107, 111, 112, 195).
It was formerly called the Herrin Limestone in southern Illinois.
The Brereton Limestone is present in southwestern Indiana and is quite persistent in western Kentucky, where it is called the Providence Limestone Member. It is correlated with the Myrick Station Member of Missouri.
Extent and Thickness
It is commonly less than 5 feet thick, but in places it is as thick as 18 feet.
The Brereton Limestone is a distinctive marker unit widely developed throughout much of the Illinois Basin (fig P-3B). It is usually dark gray, argillaceous and fine grained. In northern Illinois it contains black phosphatic nodules. It is absent in areas where cut by channels in which the Anvil Rock Sandstone was deposited. It thins and disappears over thick deposits of the silty gray shale that locally overlies the Herrin (No. 6) Coal. In parts of southwestern, western, and eastern Illinois, the Brereton Limestone or the Anna Shale are lenticular and pinch out in places. Where both are absent, the overlying Lawson Shale or strata associated with the Jamestown Coal locally form the roof of the Herrin Coal. In southern and parts of west-central Illinois the Brereton is commonly overlain by a few inches to a few feet of the dark gray calcareous shale that underlies the Jamestown Coal. In the rest of the state the limestone is overlain by the Lawson Shale.
It has an open-marine fauna dominated by brachiopods, crinoids, and fusulinids.
SAVAGE, T. E., 1927, Significant breaks and overlaps in the Pennsylvanian rocks of Illinois: American Journal of Science, v. 14, p. 307-316.
WANLESS, H. R., 1956, Classification of the Pennsylvanian rocks of Illinois as of 1956: Illinois State Geological Survey Circular 217, 14 p.
WANLESS, H. R., 1957, Geology and mineral resources of the Beardstown, Glasford, Havana, and Vermont Quadrangles: Illinois State Geological Survey Bulletin 82, 233 p.
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