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Figs. 3, 10, 16. Briton member of Mifflin formation. Limestone or dolomite. Thickness 10 feet. Shown on columnar section as overlying Hazelwood member (new) and underlying Dement member (new) of Grand Detour formation (new). Age is Middle Ordovician.
[Notable exposures in Dixon-Oregon area, northern IL.]
Source: US geologic names lexicon (USGS Bull. 1200, p. 485).
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 ( ).
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