Historical:Elviran Stage

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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
Chronostratigraphy: Paleozoic Erathem >>Mississippian Subsystem >>Chesterian Series >>Elviran Stage
Allostratigraphy: Kaskaskia Sequence

Authors

Elwood Atherton, Charles Collinson, and Jerry A. Lineback

Name Origin

The Elviran Stage (Swann, 1963, p. 23, 65), originally called the Elvira Group (J. M. Weller, 1939), is named for Elvira Township, Johnson County (12S-2E).

Definition

The Elviran Stage is the youngest stage of the Chesterian Series. It includes the nine formations younger than the Glen Dean Limestone (fig. M-25).

Description

The limestones of the Elviran Stage are generally darker and finer grained and contain more silt and argillaceous material and less abundant fossils than the older Chesterian limestones.

Fossils

Representative fossils include Pentremites fohsi, Pterotocrinus menardensis, Composita subquadrata, Eumetria costata, and Sulcatopinna missouriensis.

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, J. M., 1939, Mississippian System: Kansas Geological Society Guidebook, 13th Annual Field Conference, southwestern Illinois and southeastern Missouri, p. 131-137.

ISGS Codes

Stratigraphic Code Geo Unit Designation
4030
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