Historical:Clement 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: Ottawa Limestone Megagroup >>Platteville Group >>Plattin Subgroup >>Grand Detour Formation >>Clement Member
Chronostratigraphy: Paleozoic Erathem >>Ordovician System >>Champlainian Series >>Blackriveran Stage
Allostratigraphy: Tippecanoe Sequence


H. B. Willman and T. C. Buschbach

Name Origin

The Clement Member of the Grand Detour Formation (Templeton and Willman, 1963, p. 86) is named for Clement Station, Ste. Genevieve County, Missouri, which is 7 miles north of the type section.

Type Section

The type section of the Clement Member is located in a ravine 0.5 mile north of the village of Zell (W1/4 34, 38N-8E), where it is 13 feet thick.

Extent and Thickness

The Clement Member is only 1-4 inches thick where locally present in the northern outcrop area. It is 6 feet thick in outcrops near Cape Girardeau.


The Clement consists of purplish gray, medium- to coarse-grained calcarenite. Where thick, it occurs in 2-15 inch beds that are locally cross bedded. It grades to calcarenitic limestone in some areas.


TEMPLETON, J. S., and H. B. WILLMAN, 1963, Champlainian Series (Middle Ordovician) in Illinois: Illinois State Geological Survey Bulletin 89, 260 p.

ISGS Codes

Stratigraphic Code Geo Unit Designation