- Usage in publication:
-
- Duncan Mills Member
- Modifications:
-
- Named
- Dominant lithology:
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- Sand
- Gravel
- Silt
- AAPG geologic province:
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- Illinois basin
Summary:
Named as member of Glasford Formation (new) for Duncan Mills, Fulton Co, IL. Type section 4 mi south of Duncan Mills, exposures in Enion Section, NW/4 SW/4 SE/4 sec 32, T4N, R3E. At type, consists of glacially derived sand, and sand and gravel with some silt, generally deeply weathered. Is bounded by Hulick Till Member (new) above and Kellerville Till Member (new) below; is recognized as a member only when it is contained between these two bounding till units. Is also described in the Cottonwood School, Lewistown, and Tindall School Sections (western part of Illinois basin). Clay mineral composition given in table 5. Is as thick as 30 ft and has previously been called Jacksonville-Buffalo Hart deposits (Wanless, 1957). Locally contains deposits in both the Monican and Liman Substages of the Illinoian Stage. Contains outwash of the retreating Kellerville glacier and deposits of the advancing Hulick glacier.
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 ([ ]).