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Map showing publication footprint
  • Usage in publication:
    • Gilchrist shale
  • Modifications:
    • Original reference
  • Dominant lithology:
    • Shale
  • AAPG geologic province:
    • Illinois basin
Publication:

Wanless, H.R., 1929, Geology and mineral resources of the Alexis quadrangle: Illinois Geological Survey Bulletin, no. 57, 230 p.


Summary:

Pg. 49, 73, 83, 88, 122, 142. Gilchrist shale in Pottsville formation. Blue-gray to greenish shale, micaceous in some beds; plant impressions irregularly distributed. Thickness 20 to 100+ feet. Complete thickness is penetrated by coal-test boring near Gilchrist, in sec. 17, T. 14 N., R. 2 W., Greene Township, Mercer County, northwestern Illinois, whence name. Well exposed in pits of Hydraulic Press Brick Co. at Shale City and of NW Clay Mfg. Co. at Griffin. Lies 6 to 13+/- feet below top of Pottsville, or base of Colchester coal, in Alexis quadrangle. Age is Pennsylvanian.

Source: US geologic names lexicon (USGS Bull. 896, p. 818-819).


Map showing publication footprint
  • Usage in publication:
    • Gilchrist shale
  • Modifications:
    • Revised
  • AAPG geologic province:
    • Illinois basin
Publication:

Wanless, H.R., 1939, Pennsylvanian correlations in the Eastern Interior and Appalachian coal fields: Geological Society of America Special Paper, 17, 130 p.


Summary:

Pg. 84. Gilchrist shale in Carbondale formation, a little below Colchester (No. 2) coal. Age is Pennsylvanian.

Source: US geologic names lexicon (USGS Bull. 1200, p. 1506).


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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