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National Geologic Map Database
Geologic Unit: Butano
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Map showing publication footprint
  • Usage in publication:
    • Butano sandstone*
  • Modifications:
    • Named
  • Dominant lithology:
    • Sandstone
  • AAPG geologic province:
    • California Coast Ranges province
Publication:

Branner, J.C., Newsom, J.F., and Arnold, Ralph, 1909, Santa Cruz folio, California: U.S. Geological Survey Geologic Atlas of the United States Folio, GF-163, 11 p., scale 1:125,000


Summary:

[Named] for exposures on Butano Ridge, San Mateo Co, CA. Outcrops in triangular area, eastern point of which is San Lorenzo River, 4 mi north of town of Boulder Creek, Santa Cruz Co, CA. Consists of medium- to coarse-grained massive brown and buff sandstone with minor pebbly beds and dark-colored shale. Is about 2000 ft thick. Supposed Butano rocks overlie Chico sandstone about 0.5 mi south of mouth of Pescadero Creek which contain few fossils. No fossils found in typical Butano sandstone. Conformably underlies San Lorenzo formation. Age is Eocene or Oligocene.

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


Map showing publication footprint
  • Usage in publication:
    • Butano sandstone*
  • Modifications:
    • Areal extent
    • Revised
    • Age modified
    • Biostratigraphic dating
  • AAPG geologic province:
    • California Coast Ranges province
Publication:

Cummings, J.C., Touring, R.M., and Brabb, E.E., 1962, Geology of the northern Santa Cruz Mountains, California, IN Bowen, O.E., ed., Geologic guide to the oil and gas fields of northern California: California Division of Mines and Geology Bulletin, no. 181, p. 179-220, (incl. geologic map, scale 1:51,200)


Summary:

Type section designated along Little Boulder Creek [in SW/4 sec.22, SE/4 sec.21 and N/2 sec.28 T8S R3W] Big Basin 7.5' quad, San Mateo and Santa Cruz Cos, CA. Has wider distribution than Branner and others (1909) realized. Underlies most of area between Montara and Ben Lomond Mountains and along LaHonda and Coal Creeks. At mouth of Pescadero rocks are here referred to Mindego formation. Is thought to be 6000 feet thick. Unconformably overlies Locatelli formation. Grades upward into San Lorenzo formation except in few places. Overlapped by Monterey shale in western part of district. Age is Eocene (Narizian) based on fauna (Schenck, 1963).

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


Map showing publication footprint
  • Usage in publication:
    • Butano Sandstone*
  • Modifications:
    • Age modified
  • AAPG geologic province:
    • California Coast Ranges province
Publication:

Brabb, E.E., and Pampeyan, E.H., 1983, Geologic map of San Mateo County, California: U.S. Geological Survey Miscellaneous Investigations Series Map, I-1257-A, scale 1:62,500


Summary:

Consists of about 3000 m of light-gray to buff very fine- to very coarse-grained arkosic sandstone with dark-gray to brown mudstone and shale and with conglomerate present locally in lower part. Age is early and middle Eocene since Two-Bar Shale Member of San Lorenzo Formation which overlies unit is middle and late Eocene in age.

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


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Asterisk (*) indicates published by U.S. Geological Survey authors.

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