Where: Ventura County, California (34.3° N, 119.0° W: paleocoordinates 32.9° N, 110.8° W)

• coordinate based on political unit

• small collection-level geographic resolution

When: Sespe Formation, Arikareean (29.5 - 18.5 Ma)

• Mason and Swisher 1989: "An overall age of 28.2 ± 0.2 Ma (weighted average) is indicated for the Willard Canyon tuff..." which is "60 m (200 ft.) above the top of Stock's (1934) "Leptauchenid Zone," and about 337 m (1100 ft.) above the type locality of Sespia californica."

•Table 3 has CIT 160 above the tuff.

•The Zemorrian-Saucesian Pacific Coast benthic foraminiferal stage boundary is approximately coincident and has been dated at 22 to 23 Ma, thus providing a minimum age for the Sespe-Vaqueros contact at South Mountain.

Environment/lithology: fluvial-lacustrine; sandstone and mudstone

Size class: macrofossils

Reposited in the LACM

Primary reference: M. A. Mason and C. C. Swisher. 1989. New evidence for the age of the South Mountain local fauna, Ventura County, California. Contributions in Science, Natural History Museum of Los Angeles County 410:1-9 [J. Alroy/J. Alroy/P. Holroyd]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 17673: authorized by John Alroy, entered by John Alroy on 15.05.2002

Creative Commons license: CC BY (attribution)