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Map showing publication footprint
  • Usage in publication:
    • Piedras Altas formation
  • Modifications:
    • Named
  • Dominant lithology:
    • Conglomerate
    • Sandstone
  • AAPG geologic province:
    • California Coast Ranges province
Publication:

Taliaferro, N.L., 1943, Geologic history and structure of the central Coast Ranges of California, IN Jenkins, O.P., and others, Geologic formations and economic development of the oil and gas fields of California; in four parts, including outline geologic map showing oil and gas fields and drilled areas: California Division of Mines Bulletin, no. 118, pt. 2, p. 119-163.


Summary:

[Asuncion group] "is divided into the Cantinas sandstones, the Godfrey shales, and the Piedras Altas formation" in southern Santa Lucia Range. Late Cretaceous age assigned to group.

Source: GNU records (USGS DDS-6; Menlo GNULEX).


Map showing publication footprint
  • Usage in publication:
    • Piedras Altas Formation*
  • Modifications:
    • Reference
    • Age modified
  • AAPG geologic province:
    • California Coast Ranges province
Publication:

Seiders, V.M., 1989, Geologic map of the Burnett Peak quadrangle, Monterey and San Luis Obispo Counties, California: U.S. Geological Survey Geologic Quadrangle Map, GQ-1658, 1 sheet, scale 1:24,000 [http://ngmdb.usgs.gov/Prodesc/proddesc_470.htm]


Summary:

Piedras Altas Formation of Asuncion Group (Taliaferro, 1943) is designated a principal reference section in Piedras Hills (35 deg 52'N, 121 deg 12' 30"W) Burnett Peak quad, Monterey Co, CA. Reference locality is at outcrops in nearby Palisades on north bank of Nacimiento River, sec.29 T24S R8E of Bryson quad, San Luis Obispo Co, CA. Extends in narrow belt southeast across Burnett Peak quad into Bryson quad. Similar rocks on southeast shore of Lake Nacimiento may be eastern extension. Composed of red conglomerate and sandstone. Is 350 m thick at principal reference section. Unconformably overlies Shut-in and El Piojo Formations (both new). Top part of unit is not exposed. No fossils found. Probably Tertiary(?) age since it is unconformable on upper Maastrichtian rocks.

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 ([ ]).

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