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.
H. B. Willman and T. C. Buschbach
The Edenian Stage of the Cincinnatian Series (Newberry, 1873, table opp. p. 89; Twenhofel et al., 1954, chart).
The Edenian Stage is based on the Eden Group, named for Eden Park in Cincinnati, Ohio.
The Edenian Stage is the basal stage of the Cincinnatian Series. In Illinois the Edenian Stage includes the Cape Limestone and the lower part of the Scales Shale (essentially the part underlying the Upper Depauperate Zone), which consists of the Thebes Sandstone Member and probably the Orchard Creek Shale Member in extreme southern Illinois and the middle and lower parts of the Elgin Shale Member elsewhere.
Extent and thickness
The presence of dark brown to nearly black shale is characteristic of the Elgin Shale Member and lower Edenian strata in the type region of the Cincinnatian.
Well log characteristics
Age and correlation
Environments of deposition
NEWBERRY, J. S., 1873, General geological relations and structure of Ohio: Ohio Geological Survey Report 1, part 1, p. 1-167.
TWENHOFEL, W. H., et al., 1954, Correlation of the Ordovician formations of North America: Geological Society of America Bulletin, v. 65, p. 247-298.
|Stratigraphic Code||Geo Unit Designation|