Spar Mountain Sandstone Member

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Lithostratigraphy: Mammoth Cave Limestone Megagroup >>Ste. Genevieve Limestone >>Spar Mountain Sandstone Member
Chronostratigraphy: Paleozoic Erathem >>Mississippian Subsystem >>Valmeyeran Series
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 Spar Mountain Sandstone Member of the Ste. Genevieve Limestone (Tippie, 1945, p. 1657).


Named for Spar Mountain, Hardin County.

Other names


Type section

Type location

The type section of the Spar Mountain Sandstone Member is located on Spar Mountain, Hardin County where the section is exposed on the south-facing slope (NE 4, 12S-9E).

Type author(s)

Type status

Reference section

Reference location

Reference author(s)

Reference status

Stratigraphic relationships

The Spar Mountain Sandstone Member of the Ste. Genevieve Limestone overlies the Fredonia Limestone Member.

Extent and thickness

In the type section the Spar Mountain is 8-15 feet thick. The Spar Mountain extends throughout most of the area of the Ste. Genevieve (fig. M-22).


In the type locality the Spar Mountain Member consists of light gray to greenish gray, calcareous, glauconitic sandstone or siltstone grading to very sandy limestone. Lenses of similar sandstone and sandy calcarenite occur sporadically at other levels in the Ste. Genevieve, and the Spar Mountain is difficult to differentiate from them in some areas. It is erratic in thickness and has a varied lithology, including beds of dolomite, limestone, sandy limestone, sandstone, and thin shale. In the northern part of its extent, it is as much as 40 feet thick. In the western part of the basin- for example, in western Washington County- the Spar Mountain grades laterally into the Aux Vases Sandstone and is separated from it by vertical cut-off.




Well log characteristics


Age and correlation

Environments of deposition

Economic importance

“Spar Mountain” or “Rosiclare” are informal names applied to producing zones in the Spar Mountain Sandstone Member of the Ste. Genevieve Limestone.



TIPPIE, F. E., 1945, Rosiclare-Fredonia contact in and adjacent to Hardin and Pope Counties, Illinois: American Association of Petroleum Geologists Bulletin, v. 29, p. 1654-1663; Illinois State Geological Survey Report of Investigations 112.

ISGS Codes

Stratigraphic Code Geo Unit Designation