- Usage in publication:
-
- Ardath Shale*
- Modifications:
-
- Named
- Dominant lithology:
-
- Shale
- AAPG geologic province:
-
- Peninsular Ranges province
Summary:
Named as formation in La Jolla Group for exposures on east side of Rose Canyon, where its type section is 800 m south of Ardath Road intersection with Interstate Route 5, La Jolla quad, San Diego Co, CA. Previously included as part of Rosewood Canyon Member (Hanna, 1926) of La Jolla Formation (Clark, 1929). Consists of uniform, weakly fissile olive-gray silty shale. Upper part contains thin beds of medium-grained sandstone, and concretionary beds with molluscan fossils. Estimated 70 m thick at its type. Conformably overlies Mount Soledad Formation (new); conformably underlies and intertongues with Scripps Formation (new), interfingers with Torrey Sandstone (all of La Jolla Group). Assigned early middle Eocene age, based on fossil evidence.
Source: GNU records (USGS DDS-6; Menlo GNULEX).
- Usage in publication:
-
- Ardath Shale
- Modifications:
-
- Biostratigraphic dating
- AAPG geologic province:
-
- Peninsular Ranges province
Summary:
Fossil lists of gastropods and pelecypods with locations from Ardath Shale indicate "Domengine Stage" (middle Eocene).
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 ([ ]).