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Geologic Unit: Hercules
Map showing publication footprint
  • Usage in publication:
    • Hercules shale member*
  • Modifications:
    • Named
  • Dominant lithology:
    • Shale
  • AAPG geologic province:
    • California Coast Ranges province
Publication:

Lawson, A.C., 1914, San Francisco folio, California, Tamalpais, San Francisco, Concord, San Mateo, and Hayward quadrangles: U.S. Geological Survey Geologic Atlas of the United States Folio, GF-193, 24 p., scale 1:62,500


Summary:

Named as member of Briones sandstone of Monterey group for Hercules Station on San Pablo Bay, Concord 15' quad, Contra Costa Co, CA. Occurs in northern part of quad. Consists of bituminous shale about 500 ft thick. Map legend gives age as Miocene.

Source: GNU records (USGS DDS-6; Menlo GNULEX).


Map showing publication footprint
  • Usage in publication:
    • [Hercules Shale Member*]
  • Modifications:
    • Revised
  • AAPG geologic province:
    • California Coast Ranges province
Publication:

Murata, K.J., and Whiteley, K.R., 1973, Zeolites in the Miocene Briones Sandstone and related formations of the central Coast Ranges, California: U.S. Geological Survey Journal of Research, v. 1, no. 3, p. 255-265.


Summary:

Briones Sandstone [and its Hercules Shale Member] are part of San Pablo Group which is late Miocene in age.

Source: GNU records (USGS DDS-6; Menlo 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 ([ ]).

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