Troutman Member

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Lithostratigraphy: Hunton Limestone Megagroup >>Kankakee Formation >>Troutman Member
Chronostratigraphy: Paleozoic Erathem >>Silurian System >>Alexandrian Series
Allostratigraphy: Tippecanoe 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)

H. B. Willman and Elwood Atherton


Original description

The Troutman Member of the Kankakee Formation (Willman, 1973, p. 18).


Named for Troutman Grove Cemetery, Will County, 2 miles south of the type section.

Other names


Type section

Type location

Two miles north of Troutman Grove Cemetery, the lower part of the type section of the Troutman Member is in the same exposure as the Drummond Member, whereas the upper part is in a small quarry one-fourth of a mile east (SW NW SE 30, 35N-10E). The two sections are correlated by a thin bed of white clay that occurs near or slightly above the middle of the member in both sections and also in nearly all exposures of the member in northeastern Illinois.

Type author(s)

Type status

Reference section

Reference location

Reference author(s)

Reference status

Stratigraphic relationships

The Troutman Member overlies the Offerman Member of the Kankakee Formation.

Extent and thickness

The Troutman is 27 feet thick in the type locality but thins to 11 feet along the Kankakee River.


The Troutman Member has the typical lithology of the Kankakee Formation. It contains a few widely scattered nodules of chert.




Well log characteristics


Age and correlation

Environments of deposition

Economic importance



WILLMAN, H. B., 1973, Rock stratigraphy of the Silurian System in northeastern and northwestern Illinois: Illinois State Geological Survey Circular 479, 55 p.

ISGS Codes

Stratigraphic Code Geo Unit Designation