- Usage in publication:
-
- Boulder Wash group
- Modifications:
-
- Original reference
- AAPG geologic province:
-
- South Western Overthrust
Summary:
Pg. 1407-1409. Boulder Wash group. Stratified series, lower part of which is dark-gray compact heavy dolomite that weathers rusty brown, and is interrupted by thin layers of greenish compact shale 3 or 4 feet above base of unit; maximum thickness 200 feet. Above dolomite, and separated from it by highly irregular surface of erosion is coarse breccia which fills valleys in the dolomite; thickness several hundred feet and probably exceeds 1,000 feet. Total thickness possibly exceeds 2,000 feet. Unconformably overlies Precambrian schist. Age is Precambrian(?); [=(?) the Grand Canyon series].
[Type locality]: north of Colorado River Canyon and west of Boulder Wash, Clark Co., southeastern NV.
Source: US geologic names lexicon (USGS Bull. 1200, p. 439-440); supplemental information (in brackets) from GNU records (USGS DDS-6; Menlo GNULEX).
- Usage in publication:
-
- Boulder Wash group
- Modifications:
-
- Redescribed
- Age modified
- AAPG geologic province:
-
- South Western Overthrust
Summary:
Pg. 1804 (fig. 2). Boulder Wash group. Breccia, dolomite, andesite, rhyolite, and intrusives. Age is Tertiary(?).
[Example of application of engineering geology, Boulder Dam and Reservoir, in area of type locality, Boulder Wash, north of Colorado River and west of Virgin River, Lake Mead area, Clark County, Nevada.]
Source: US geologic names lexicon (USGS Bull. 1200, p. 439-440).
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 ([ ]).