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Geologic Unit: Coggon
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Map showing publication footprint
  • Usage in publication:
    • [Coggon] Member
  • Modifications:
    • Revised
  • AAPG geologic province:
    • Iowa shelf
    • Wisconsin arch
Publication:

Witzke, B.J., Bunker, B.J., and Rogers, F.S., 1988, Eifelian through lower Frasnian stratigraphy and deposition in the Iowa area, Midcontinent, U.S.A., IN McMillan, N.J., Embry, A.F., and Glass, D.J., eds., Devonian of the World; proceedings of the 2nd international symposium on the Devonian System; Volume I, Regional synthesis: Canadian Society of Petroleum Geologists Memoir, 14, p. 221-250.


Summary:

Assigned as the lower member of the Otis Formation, middle formation of the Wapsipinicon Group (rank raised). Overlies Bertram Formation of Wapsipinicon. Underlies Cedar Rapids Member of Otis. Consists of medium- to thick-bedded dolomite. Has scattered molds of the brachiopod EMANUELLA, rare specimens of gastropods, rostroconchs, and trilobites, and, at one locality, the conodont OZARKODINA RAASCHI. Otis is limited to east-central IA (Iowa shelf) and northwest IL (Wisconsin arch). Areal extent of [Coggon] not stated. Is a restricted marine deposit. Nomenclature charts. Graphic sections. Of early Middle Devonian, Eifelian age.

Source: GNU records (USGS DDS-6; Denver GNULEX).


For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.

Asterisk (*) indicates published by U.S. Geological Survey authors.

"No current usage" (†) implies that a name has been abandoned or has fallen into disuse. Former usage and, if known, replacement name given in parentheses ( ).

Slash (/) indicates name conflicts with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005, 2021). May be explained within brackets ([ ]).

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