Delwood Coal Member

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Lithostratigraphy: McCormick Group >>Abbott Formation >>Delwood Coal Member
Chronostratigraphy: Paleozoic Erathem >>Pennsylvanian Subsystem >>Atokan 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 Delwood Coal Member of the Abbott Formation (Weller, 1940, p. 40).


Named for Delwood, Pope County.

Other names


Type section

Type location

The type locality consists of exposures near the village of Delwood (NW NW 3, 11S-6E) (Wanless, 1956, p. 9).

Type author(s)

Type status

Reference section

Reference location

Reference author(s)

Reference status

Stratigraphic relationships

Extent and thickness

The Delwood Coal has been identified in several widely scattered outcrops in southern Illinois and in places is more than 3 feet thick. It is probably not continuous and locally may have been removed by channeling during development of a younger sandstone. Very little is known of the distribution of the Delwood in subsurface north of the outcrop belt.


The name Delwood may have been applied to more than one coal and, in fact, recent palynological studies indicate the type Delwood may be equivalent to the Bidwell Coal Member of the lower part of the Spoon Formation.




Well log characteristics


Age and correlation

The Delwood has been correlated with the Pope Creek Coal of western Illinois, the Upper Block Coal Member of Indiana, and the No. 3 (Ice House) coal of western Kentucky.

Environments of deposition

Economic importance



WANLESS, H. R., 1956, Classification of the Pennsylvanian rocks of Illinois as of 1956: Illinois State Geological Survey Circular 217, 14 p.
WELLER, J. M., 1940, Geology and oil possibilities of extreme southern Illinois: Illinois State Geological Survey Report of Investigations 71, 71 p.

ISGS Codes

Stratigraphic Code Geo Unit Designation