Round Mountain Silt (Miocene of the United States)

Where: Kern County, California (35.3° N, 119.3° W: paleocoordinates 34.5° N, 115.0° W)

• coordinate based on nearby landmark

• basin-level geographic resolution

When: Upper Member (Round Mountain Silt Formation), Middle Miocene (16.0 - 11.6 Ma)

• The Round Mountain Silt is unconformably overlain by the Santa Margarita Formation; the contact is placed at the base of a massive sand that overlies sandy siltstone. The contact with the underlying Oclese sand is drawn at the toip of a very fine silty sand. The upper units of the formation comprises 120 ft of light-gray to greenbish-black clayey siltstone.

• member-level stratigraphic resolution

Environment/lithology: offshore; gray, silty, sandy shale

• Light-gray to greenbish-black clayey siltstone

Size class: macrofossils

Reposited in the CAS, LACM, UCMP

Collection methods: quarrying,

• Collections housed at various institutes: USGS (Wasington and Menlo Park), UCMP, LACM, CAS, Stanford University, UCLA, UCR.

Primary reference: W.O. Addicott. 1970. Miocene Gastropods and Biostratigraphy of the Kern River Area, California. United States Geological Survey Professional Paper 642:1-172 [A. Miller/A. Hendy/A. Hendy]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 38042: authorized by Austin Hendy, entered by Austin Hendy on 02.04.2004

Creative Commons license: CC BY (attribution)

Taxonomic list

• Exhaustive for gastropods; includes some occaisional other taxa