Ford Station Limestone Member

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Lithostratigraphy: Pope Megagroup >>Clore Formation >>Ford Station Limestone Member
Chronostratigraphy: Paleozoic Erathem >>Mississippian Subsystem >>Chesterian Series >>Elviran Stage
Allostratigraphy: Kaskaskia Sequence

Primary source

Willman, H. B., Elwood Atherton, T. C. Buschbach, Charles Collinson, John C. Frye, M. E. Hopkins, Jerry A. Lineback, and Jack A. Simon, 1975, Handbook of Illinois Stratigraphy: Illinois State Geological Survey Bulletin 95, 261 p.

Contributing author(s)

Elwood Atherton, Charles Collinson, and Jerry A. Lineback


Original description

The Ford Station Limestone Member of the Clore Formation (Swann, 1963, p. 40, 42).


Named for the Ford Station siding of the Missouri Pacific Railroad, Randolph County.

Other names


Type section

Type location

The type section of the Ford Station Limestone is located near the Ford Station siding of the Missouri Pacific Railroad, Randolph County in an abandoned quarry (NW SE 33, 7S-6W).

Type author(s)

Type status

Reference section

Reference location

Reference author(s)

Reference status

Stratigraphic relationships

The Ford Station Limestone Member is the upper member of the Clore Formation.

Extent and thickness

It is 38 feet thick in the type section but ranges from 20-50 feet thick.


It consists of interbedded limestone and shale that include rare lenses of sandstone. Most of the shale in the Ford Station Member is dark gray to dark greenish gray and is generally calcareous and fossiliferous. The limestone is gray, buff, drab, or dark brownish gray, argillaceous, and shaly . Dolomite occurs irregularly.




Well log characteristics


Age and correlation

Environments of deposition

Economic importance



SWANN, D. H., 1963, Classification of Genevievian and Chesterian (Late Mississippian) rocks of Illinois: Illinois State Geological Survey Report of Investigations 216, 91 p.

ISGS Codes

Stratigraphic Code Geo Unit Designation