Virgilian Series

Lithostratigraphy: McLeansboro Group
Chronostratigraphy: Paleozoic Erathem >>Pennsylvanian Subsystem >>Virgilian 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

Name

Original description

The Virgilian Series of the Pennsylvanian System (Moore, 1931, correlation chart).

Derivation

Named for Virgil, Greenwood County, Kansas, which lies in the outcrop belt of these rocks.

Stratigraphic relationships

In Illinois it includes all Pennsylvanian strata above a position a few feet below the coal that occurs just below the Shumway Limestone Member (Willman et al., 1967). It thus includes the upper half of the Mattoon Formation of the McLeansboro Group (fig P-2).

Fig. P-2 -- Classification of the Pennsylvanian System. In the graphic column, blank space indicates gray shale. Named members are listed to the right of the graphic column.

Fossils

Where marine rocks are found, as they are in Illinois and the Midcontinent Region, the Virgilian includes strata containing fusulinids of the genus Triticites that are more advanced than the subgenus Kansanella found in lower strata. The upper limit is placed just below the first appearance of the Permian genera Pseudoschwagerina and/or Schwagerina, but neither have been found in the Illinois Basin. The spores and plant-compression fossils in Virgilian rocks are not well known.

References

MOORE, R. C., 1931, Pennsylvanian cycles in the northern Midcontinent region: Illinois State Geological Survey Bulletin 60, p. 247-257.
WILLMAN, H. B., et al., 1967, Geologic map of Illinois: Illinois State Geological Survey.

ISGS Codes

Stratigraphic Code	Geo Unit Designation
1530	--