Davenport Member

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Lithostratigraphy: Hunton Limestone Megagroup >>Wapsipinicon Limestone >>Davenport Member
Chronostratigraphy: Paleozoic Erathem >>Devonian System >>Middle Devonian Series
Allostratigraphy: Kaskaskia Sequence

Primary source

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.

Contributing author(s)

Charles Collinson and Elwood Atherton


Original description

Davenport Member (Stainbrook, 1935).


The Davenport Member of the Wapsipinicon Limestone is named for Davenport, Scott County, Iowa, near which it is exposed.

Other names


As originally used, the name "Davenport" was applied to a Lower Davenport Member and an Upper Davenport Member. However, the upper, fossiliferous member was later assigned to the Cedar Valley, and the lower member was renamed the Davenport Member (Stainbrook, 1935).

Type section

Type location

No type section has be designated for the Davenport Member of the Wapsipinicon Limestone.

Type author(s)

Type status

Reference section

Reference location

Reference author(s)

Reference status

Stratigraphic relationships

The Davenport Member of the Wapsipinicon Limestone (Norton, 1894, p. 24; Stainbrook, 1935, p. 252), the uppermost member, overlies the Spring Grove Member and is overlain by the Cedar Valley Limestone.

Extent and thickness

The Davenport is 40-50 feet thick in subsurface, but is 30 feet thick where exposed in the quarries at Milan and Rock Island and only 18 feet thick across the river near Linwood, Iowa.


The Davenport Member consists of pure, hard, light gray to brownish gray, fine-grained to lithographic limestone. It contains many beds of limestone breccia and, in subsurface, anhydrite and gypsum.




Well log characteristics


No fossils have been found in the Davenport Member.

Age and correlation

Environments of deposition

Economic importance



NORTON, W. H., 1894, Notes on the lower strata of the Devonian Series in eastern Iowa: Iowa Academy of Science Proceedings 1, part 4, p. 22-24.
STAINBROOK, M. A., 1935, Stratigraphy of the Devonian System of the Upper Mississippi Valley: Kansas Geological Society Guidebook, 9th Annual Field Conference, p. 248-260.

ISGS Codes

Stratigraphic Code Geo Unit Designation