Pokeberry Limestone Member
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.
M. E. Hopkins and J. A. Simon
The Pokeberry Limestone Member of the Carbondale Formation (Wanless, 1939, p. 17, 98).
Named for Pokeberry School, Schuyler County.
Pokeberry School is near the type locality (NW 26, 2N-1W) (Wanless, 1956, p. 11; 1957, p. 113, 188).
Where it is found, it is 15 feet above the Herrin Coal and 9 feet below the Danville (No. 7) Coal.
Extent and thickness
The limestone is known only in the type area.
It is a gray, dense, locally conglomeratic or brecciated limestone containing large fossils, most of them brachiopods. It has a very knobby upper surface. The Pokeberry Limestone is not shown on the geologic column (fig. P-2).
Well log characteristics
Age and correlation
It was correlated by Wanless (1957, p. 113) with the Conant Limestone, but its position and correlation are uncertain. It may correlate with the Bankston Fork Limestone.
Environments of deposition
WANLESS, H. R., 1939, Pennsylvanian correlations in the Eastern Interior and Appalachian coal fields: Geological Society of America Special Paper 17, 130 p.
WANLESS, H. R., 1956, Classification of the Pennsylvanian rocks of Illinois as of 1956: Illinois State Geological Survey Circular 217, 14 p.
WANLESS, H. R., 1957, Geology and mineral resources of the Beardstown, Glasford, Havana, and Vermont Quadrangles: Illinois State Geological Survey Bulletin 82, 233 p.
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