Historical:Wyota Member

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Handbook of Illinois Stratigraphy
Series Bulletin 95
Author H. B. Willman, Elwood Atherton, T. C. Buschbach, Charles Collinson, John C. Frye, M. E. Hopkins, Jerry A. Lineback, Jack A. Simon
Date 1975
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Lithostratigraphy: Ottawa Limestone Megagroup >>Galena Group >>Kimmswick Subgroup >>Dunleith Formation >>Wyota Member
Chronostratigraphy: Paleozoic Erathem >>Ordovician System >>Champlainian Series >>Trentonian Stage
Allostratigraphy: Tippecanoe Sequence

Authors

H. B. Willman and T. C. Buschbach

Name Origin

The Wyota Member of the Dunleith Formation (Templeton and Willman, 1963, p. 124), the uppermost member in northern Illinois, overlies the Wall Member, and is named for Wyota Street in East Dubuque, Jo Daviess County, near the type section.

Type Section

The type section of the Wyota Member is part of the Dunleith Formation type section (in an exposure in the Mississippi River bluffs on the north side of East Dubuque (SE 19, 29N-2W))(fig. O-2B), where the Wyota Member is 19.9 feet thick.

Extent and Thickness

The Wyota Member is commonly 18-20 feet thick.

Description

Most of the Wyota Member is purer than the Wall but less pure than the overlying Sinsinawa Member of the Wise Lake Formation. It is characterized by the persistence of thin beds with argillaceous flecks, particularly in the upper 10 feet, and by abundant chert nodules in well defined bands. The upper 2-4 feet is slightly argillaceous, locally shaly, and in many exposures makes a strong reentrant that marks the top of the Dunleith Formation.

References

TEMPLETON, J. S., and H. B. WILLMAN, 1963, Champlainian Series (Middle Ordovician) in Illinois: Illinois State Geological Survey Bulletin 89, 260 p.

ISGS Codes

Stratigraphic Code Geo Unit Designation
7620
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