- Usage in publication:
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- Calhoun coal member
- Modifications:
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- Original reference
- Dominant lithology:
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- Coal
- AAPG geologic province:
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- Illinois basin
Summary:
Pg. 40, 51 (table 1), 82, pl. 1. Calhoun coal member of Mattoon formation (new) of McLeansboro group. Name applied to coal immediately below Bonpas limestone member (new). Stratigraphically above Trowbridge coal member (new). Thickness 16 inches. Recognized in central and southeastern Illinois. Age is Pennsylvanian. Report presents new rock-stratigraphic classification of Pennsylvanian strata in Illinois. Cyclical classification retained but is entirely independent of rock-stratigraphic classification.
Type locality: in NE/4 NE/4 NE/4 sec. 6, T. 2 N., R. 14 W., Richland Co., southeastern IL. Named from village of Calhoun, 2 mi west of type exposure.
Source: Publication; US geologic names lexicon (USGS Bull. 1200, p. 580).
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 ([ ]).