Historical:Cora Limestone Member

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Handbook of Illinois Stratigraphy
Series Bulletin 95
Author H. B. Willman, Elwood Atherton, T. C. Buschbach, Charles Collinson, John C. Frye, M. E. Hopkins, Jerry A. Lineback, Jack A. Simon
Date 1975
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Lithostratigraphy: Pope Megagroup >>Clore Formation >>Cora Limestone Member
Chronostratigraphy: Paleozoic Erathem >>Mississippian Subsystem >>Chesterian Series >>Elviran Stage
Allostratigraphy: Kaskaskia Sequence

Authors

Elwood Atherton, Charles Collinson, and Jerry A. Lineback

Name Origin

The Cora Limestone Member of the Clore Formation (Swann, 1963, p. 40-41), the lowest member, is named for Cora, Jackson County.

Type Section

The type section of the Cora Limestone Member is at the mouth of Degonia Creek Hollow (SW SE 16, 8S-5W).

Extent and Thickness

The Cora is 15-45 feet thick.

Description

It varies from dominantly limestone to dominantly shale. In both facies, the Cora is interbedded limestone and shale and locally contains sandstone lenses.

Fossils

A zone in the Cora Member in which the limestone surfaces are covered with delicate branching bryozoans is the Batostomella nitidula Peak Zone (S. Weller, 1926).

References

SWANN, D. H., 1963, Classification of Genevievian and Chesterian (Late Mississippian) rocks of Illinois: Illinois State Geological Survey Report of Investigations 216, 91 p.
WELLER, STUART, 1926, Faunal zones in the standard Mississippian section: Journal of Geology, v. 34, p. 320-335.

ISGS Codes

Stratigraphic Code Geo Unit Designation
4140
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