Exline Limestone Member

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Lithostratigraphy: McLeansboro Group >>Modesto Formation >>Exline Limestone Member
Chronostratigraphy: Paleozoic Erathem >>Pennsylvanian Subsystem >>Desmoinesian Series
Allostratigraphy: Absaroka 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)

M. E. Hopkins and J. A. Simon


Original description

The Exline Limestone Member of the Modesto Formation (Cline, 1941, p. 65-66).


Named for Exline, Appanoose County, Iowa.

Other names


Type section

Type location

Exline is near the type section (SE 6, 67N-17W).

Type author(s)

Type status

Reference section

Reference location

Reference author(s)

Reference status

Stratigraphic relationships

In some places the Exline lies immediately on the Lonsdale Limestone, but in others it is as much as 30 feet above the Lonsdale.

Extent and thickness

The Exline occurs in western Illinois where it is dark gray to black, thin- and even-bedded limestone.


In Illinois it usually is less than 3 feet thick, is underlain by black fissile shale, and is overlain by gray marine shale.




Well log characteristics


It contains well preserved plant stems and leaves, the worm tube Spirorbis, and a few marine pelecypods (Wanless, 1957, p. 120). In Iowa, the Exline contains a normal marine fauna.

Age and correlation

Environments of deposition

Economic importance



CLINE, L. M., 1941, Traverse of upper Des Moines and lower Missouri series from Jackson County, Missouri, to Appanoose County, Iowa: American Association of Petroleum Geologists Bulletin, v. 25, p. 23-72.
WANLESS, H. R., 1957, Geology and mineral resources of the Beardstown, Glasford, Havana, and Vermont Quadrangles: Illinois State Geological Survey Bulletin 82, 233 p.

ISGS Codes

Stratigraphic Code Geo Unit Designation