Also known as A 3558

Where: Baja California Sur, Mexico (26.0° N, 111.3° W: paleocoordinates 25.8° N, 110.0° W)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: San Marcos Formation, Early/Lower Pliocene (5.3 - 3.6 Ma)

• The oldest fossiliferous deposits exposed along Arroyo de Gua and Arroyo de Arce are correlatted with sediments on San Marcos Island as the fossils indicate early Pliocene. Along Arroyo de Arce the San Marcos Formation is a volcanic conglomerate containing interbedded sandstones and shell reefs. Fossils are more prevalent in the finer clastics whjich are common throughout the section implying the entire sequence is marine. About 150 ft stratigraphically below A-3557.

• bed-level stratigraphic resolution

Environment/lithology: offshore; poorly lithified sandstone and volcaniclastic conglomerate

Size class: macrofossils

Reposited in the UCMP

• Material reposited in the UCMP collections.

Primary reference: J. W. Durham. 1950. 1940 E.W. Scripps cruise to the Gulf of California. Part II - Megascopic paleontology and marine stratigraphy. Geological Society of America Memoir 43(2) [A. Miller/A. Hendy/A. Hendy]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 44042: authorized by Austin Hendy, entered by Austin Hendy on 31.08.2004

Creative Commons license: CC BY (attribution)