The National Geologic Map Database is migrating to a new infrastructure. We apologize for any service disruptions during this process.

U.S. Geological Survey Home AASG Logo USGS HOME CONTACT USGS SEARCH USGS
National Geologic Map Database
Map showing publication footprint
  • Usage in publication:
    • Eureka Valley Member
  • Modifications:
    • Named
  • AAPG geologic province:
    • Sierra Nevada province
Publication:

Slemmons, D.B., 1966, Cenozoic volcanism of the central Sierra Nevada, California, IN Bailey, E.H., ed., Geology of northern California: California Division of Mines and Geology Bulletin, no. 190, p. 199-208.


Summary:

Unit is named the Eureka Valley Member of the Stanislaus Formation. Age is late Miocene to early Pliocene.

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


Map showing publication footprint
  • Usage in publication:
    • Eureka Valley Tuff*
  • Modifications:
    • Adopted
    • Geochronologic dating
  • AAPG geologic province:
    • Sierra Nevada province
    • Great Basin province
Publication:

Noble, D.C., Slemmons, D.B., Korringa, M.K., Dickinson, W.R., Al-Rawi, Yehya, and McKee, E.H., 1974, Eureka Valley Tuff, east-central California and adjacent Nevada: Geological Society of America, Geology, v. 2, no. 3, p. 139-142.


Summary:

Eureka Valley Member of the Stanislaus Formation (Slemmons, 1966) is adopted as the Eureka Valley Tuff of the Stanislaus Group and is divided into (ascending) the Tollhouse Flat Member, By-Day Member, and Upper member. Age is late Miocene based on radiometric (K-Ar) ages.

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 ([ ]).

Accessibility FOIA Privacy Policies and Notices

USA Gov U.S. Department of the Interior | U.S. Geological Survey
Supported by the National Cooperative Geologic Mapping Program
Page Contact Information: Personnel
Page Last Modified: Thu 21 May 2026 05:26:26 PM MDT