Where: Contra Costa County, California (37.9° N, 122.1° W: paleocoordinates 37.4° N, 119.6° W)

• coordinate based on political unit

• small collection-level geographic resolution

When: Garrity Formation, Hemphillian (10.3 - 4.9 Ma)

• referred to the Orinda Fm. by Stirton but to the Mulholland Fm. by Creely et al. 1982; not directly superposed above the Orinda/Moraga/Siesta sites contra Tedford et al. 1987, but a lateral equivalent of the Bald Peak Basalt, which overlies the Siesta Fm. (Creely et al. 1982) and is dated at 7.7 (=7.91) Ma (KA on olivine: Evernden et al. 1964) superposed above the undifferentiated Contra Costa Group, including Bolinger Canyon and other "Orinda" sites of Stirton.
As discussed in Martin et al. 2023, revised stratigraphy of area by Wagner et al. 2021 places locality in the Garrity Formation, which overlies the Mulholland members of the Siesta Formation and is stratigraphically above the UCMP V3611 occurs above the

•Crow Canyon (8.2 Ma, Ar/Ar) and Bolinger Canyon (8.1 Ma Ar/Ar) and below the San Pablo Dam Tuff (7.8 Ma Ar/Ar).

Environment/lithology: terrestrial; lithology not reported

Size class: macrofossils

Reposited in the UCMP

Primary reference: R. A. Stirton. 1939. Cenozoic Mammal Remains From the San Francisco Bay Region. University of California Publications, Bulletin of the Department of Geological Sciences 24(13):339-410 [J. Alroy/J. Alroy/J. Marcot]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 19447: authorized by John Alroy, entered by John Alroy on 26.03.1995, edited by Patricia Holroyd

Creative Commons license: CC BY (attribution)