- Usage in publication:
-
- Dugger formation*
- Modifications:
-
- Original reference
- Mapped
- Dominant lithology:
-
- Sandstone
- Shale
- Coal
- Limestone
- AAPG geologic province:
-
- Illinois basin
Summary:
Dugger formation. Consists of (ascending) 55 feet of sandstone and shale locally containing two thin coal beds and massive conglomeratic limestone in places; Coal VI, which may be absent or as much as 6 feet thick; 40 to 50 feet of sandstone and shale containing thin limestone in places; Coal VII, which is generally 2.5 feet thick; and 20 feet of gray shale in places. Overlies Alum Cave member of St. Petersburg formation; unconformably underlies sandstone of Shelburn formation. Age is Middle Pennsylvanian.
Named from exposures in secs. 31 and 32, T. 8 N., R. 7 W., and in secs. 5 and 6, T. 7 N., R. 7 W., 2 mi northeast of Dugger, Sullivan Co., southeastern IN.
Source: US geologic names lexicon (USGS Bull. 1200, p. 1173).
- Usage in publication:
-
- Dugger formation*
- Modifications:
-
- Revised
- AAPG geologic province:
-
- Illinois basin
Summary:
Dugger formation. Includes Universal limestone member (new) between Coal VI and Coal VII. [Age is Late Pennsylvanian.]
Source: US geologic names lexicon (USGS Bull. 1200, p. 1173).
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 ([ ]).