Lithostratigraphy: Pope Megagroup >>Golconda Group
Chronostratigraphy: Paleozoic Erathem >>Mississippian Subsystem >>Chesterian Series >>Gasperian Stage
Allostratigraphy: Kaskaskia Sequence
Elwood Atherton, Charles Collinson, and Jerry A. Lineback
The Golconda Group (Brokaw, 1916, pl. 3; Ulrich, in Butts, 1917, p. 91-95; Swann, 1963, p. 68) is named for Golconda, Pope County.
The type section of the Golconda Group is in the bluffs of the Ohio River above Golconda (secs. 5, 8, 18, 13S-7E).
Extent and Thickness
The Golconda Group ranges from about 60 feet thick near its northern limit to over 180 feet near its southern limit.
The Golconda Group is a limestone-shale unit, but it has a sandstone member locally present in its lower part in the northeastern part of its area. It consists of the Beech Creek Limestone at the base, the Fraileys Shale, and the Haney Limestone (fig. M-25).
BROKAW, A. D., 1916, Preliminary oil report on southern Illinois: Illinois State Geological Survey Extract Bulletin 35, 13 p.
BUTTS, CHARLES, 1917, Descriptions and correlations of the Mississippian formations of western Kentucky, Part I of Mississippian formations of western Kentucky: Kentucky Geological Survey, v. 1, 119 p.
SWANN, D. H., 1963, Classification of Genevievian and Chesterian (Late Mississippian) rocks of Illinois: Illinois State Geological Survey Report of Investigations 216, 91 p.
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