Historical:State Pond Member
Lithostratigraphy: Mammoth Cave Limestone Megagroup >>Springville Shale >>State Pond Member
Chronostratigraphy: Paleozoic Erathem >>Mississippian Subsystem >>Valmeyeran Series
Allostratigraphy: Kaskaskia Sequence
Authors
Elwood Atherton, Charles Collinson, and Jerry A. Lineback
Name Origin
The State Pond Member of the Springville Shale (Collinson and Scott, 1958a, p. 5), at the base of the formation, is named for State Pond, an artificial lake a mile northwest of Jonesboro, Union County.
Type Section
The type section of the State Pond Member is in the south bank of the stream, below the spillway of the dam (NW SE 14, 12S-2W), where the member is 14-15 inches thick.
Description
The State Pond is a greenish gray, soft, glauconitic shale containing phosphate nodules.
Fossils
The State Pond Member has yielded conodonts and ostracodes typical of the Fern Glen, Burlington, and Keokuk Limestones and probably is a deep-water equivalent of all three formations.
References
COLLINSON, CHARLES, and A. J. SCOTT, 1958a, Age of the Springville Shale (Mississippian) of southern Illinois: Illinois State Geological Survey Circular 254, 12 p.
ISGS Codes
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