Lithostratigraphy: Pope Megagroup >>Degonia Sandstone
Chronostratigraphy: Paleozoic Erathem >>Mississippian Subsystem >>Chesterian Series >>Elviran Stage
Allostratigraphy: Kaskaskia Sequence
Elwood Atherton, Charles Collinson, and Jerry A. Lineback
The Degonia Sandstone (S. Weller, 1920, p. 281-290) is named for Degonia Township, Jackson County.
The type section of the Degonia Sandstone is in the bluffs of the Mississippi River and small tributaries (12-16, 21-25, 8S--5W).
Extent and Thickness
The unit ranges from 150 feet of massive sandstone in western Illinois to as little as 20 feet of shale in the southeast (fig.M-49).
The Degonia is a clastic unit, dominantly sandstone. Typically, it includes two well developed, lenticular beds of massive sandstone. The upper overlaps the lower and both are absent locally. Most of the shale is gray to dark gray, but an extensive bed of red shale occurs at the top of the formation. Thick elongate and thin sheet sand bodies occur in a dendritic pattern (Potter, 1963). A north-south sandstone body, locally more than 15 miles wide, is joined from the east by southwest-trending bodies that fill channel distributaries. In the thick bodies, the sandstone typically is white and fine grained (Atherton, 1947). In southwestern Illinois thin coal beds occur locally near the top and middle of the formation.
The Degonia contains plant remains, with Lepidodendron the most common.
ATHERTON, ELWOOD, 1947, Some Chester outcrop and subsurface sections in southeastern Illinois: Illinois Academy of Science Transactions., v. 40, p. 122-131; 1948, Illinois State Geological Survey Circular 144.
POTTER, P. E., 1963, Late Paleozoic sandstones of the Illinois Basin: Illinois State Geological Survey Report of Investigations 217, 92 p.
WELLER, STUART, 1920, Chester Series in Illinois: Journal of Geology, v. 28, p. 281-303, 395-416.
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