Historical:Beech Creek Limestone
Lithostratigraphy: Pope Megagroup >>Okaw Group >>Golconda Group >>Beech Creek Limestone
Chronostratigraphy: Paleozoic Erathem >>Mississippian Subsystem >>Chesterian Series >>Gasperian Stage
Allostratigraphy: Kaskaskia Sequence
Elwood Atherton, Charles Collinson, and Jerry A. Lineback
The Beech Creek Limestone (Malott, 1919, p. 11-15) is named for Beech Creek, Greene County, Indiana.
The type section of the Beech Creek Limestone is at the mouth of Ray's Cave, one fourth of a mile south of Beech Creek.
The Beech Creek is commonly called the "Barlow lime."
Extent and Thickness
The Beech Creek Limestone is a relatively thin limestone unit. It is very persistent and is widely used as a horizon for structure contour maps of the Illinois Basin (Bristol, 1968). The Beech Creek is unusual in that it thickens from south to north, counter to the trend of other Chesterian formations (fig. M-38). It is as much as 35-40 feet thick in the north but in areas in Hardin County it is thin, shaly, and difficult to identify. In some places the changes in thickness are abrupt and probably result from fusion of the formation with limestone beds that elsewhere are in the lower part of the Fraileys Shale.
The lower part of the Beech Creek is argillaceous, dark brownish gray, dense to lithographic limestone, usually with scattered, black, rounded grains and a few fossils. The upper part is light brownish gray, fine to coarse grained, fossiliferous, and similar to much of the limestone higher in the Golconda Group. Some thin beds of oolitic limestone are present. The Beech Creek becomes somewhat sandy eastward, and in the vicnity of Saline and southern Hamilton Counties it seems to be represented locally by a bed of calcareous sandstone.
Euphemia randolphensis, a pelecypod, and Martinia contracta, a brachiopod, are characteristic of some beds in the Beech Creek.
BRISTOL, H. M., 1968, Structure of the base of the Mississippian Beech Creek (Barlow) Limestone in Illinois: Illinois State Geological Survey Illinois Petroleum 88, 12 p.
MALOTT, C. A., 1919, "American Bottoms" region of eastern Greene County, Indiana-a type unit in southern Indiana physiography: Indiana University Studies, v. 6, 61 p.
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