U.S. Geological Survey Home AASG Logo USGS HOME CONTACT USGS SEARCH USGS
National Geologic Map Database
Geologic Unit: Chusa
Search archives
Map showing publication footprint
  • Usage in publication:
    • Chusa member
  • Modifications:
    • Original reference
  • Dominant lithology:
    • Clay
    • Bentonite
  • AAPG geologic province:
    • Gulf Coast basin
Publication:

Bailey, T.L., 1926, The Gueydan, a new middle Tertiary formation from the southwestern coastal plain of Texas: University of Texas Bulletin, no. 2645, 187 p., (incl. geologic map, scale 1:723,000)


Summary:

Pg. 65, 89-105, 178-179. Chusa member of Gueydan formation. Primarily friable tuffaceous clays and impure bentonites which have evidently been formed by action of streams on underlying Soledad and Fant members of Gueydan formation. Thickness 160+ feet. Is top member of Gueydan formation. Grades into underlying Soledad member of Gueydan formation and is unconformably or disconformably overlain by Oakville formation. Traced to northwest it overlies, apparently conformably, typical Catahoula sandstone of Gonzales and Lavaca Counties, southwestern Texas, and occupies stratigraphic position of Floeming clay. It is therefore quite possible it is of early Miocene age.
Named from exposures on slopes of La Chusa Mesa, in southeastern McMullen Co., southwestern TX coastal plain.

Source: US geologic names lexicon (USGS Bull. 896, p. 443).


Map showing publication footprint
  • Usage in publication:
    • Chusa tuff member*
  • Modifications:
    • Overview
  • AAPG geologic province:
    • Gulf Coast basin
Publication:

Wilmarth, M.G., 1930, [Selected Geologic Names Committee remarks (ca. 1900-1933) on Tertiary deposits of the Gulf Coastal Plain], IN Wilmarth, M.G., 1938, Lexicon of geologic names of the United States (including Alaska): U.S. Geological Survey Bulletin, 896, pts. 1-2, 2396 p.


Summary:

Chusa tuff member of Catahoula tuff. The Gueydan formation is now [ca. 1936] considered same as Catahoula tuff, and "Gueydan" has been abandoned by both Texas Geol. Survey and the USGS. The Chusa is therefore now treated as a member of Catahoula tuff. Age is Tertiary (early Miocene or Oligocene). Recognized in southwestern Texas Coastal Plain.

Source: US geologic names lexicon (USGS Bull. 896, p. 443).


Map showing publication footprint
  • Usage in publication:
    • Chusa Tuff Member*
  • Modifications:
    • Mapped 1:250k
  • Dominant lithology:
    • Mudstone
    • Clay
  • AAPG geologic province:
    • Gulf Coast basin
Publication:

Barnes, V.E. (project director), 1976, Geologic atlas of Texas, Crystal City-Eagle Pass sheet: University of Texas-Austin, Bureau of Economic Geology Geologic Atlas of Texas, 1 sheet, scale 1:250,000, Dolan Hoye Eargle memorial edition


Summary:

Chusa Tuff Member of Catahoula Formation. Mudstone and clay, tuffaceous, light-gray to pink, massive to irregularly bedded. Thickness about 180 feet. Is uppermost member of Catahoula Formation. Lies above Soledad Volcanic Conglomerate Member of Catahoula and below Oakville Sandstone. Age is Miocene.
[Mapped in northwestern Duval Co., southern TX.]

Source: Publication.


Search archives

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 ([ ]).

Accessibility FOIA Privacy Policies and Notices

USA Gov U.S. Department of the Interior | U.S. Geological Survey
Supported by the National Cooperative Geologic Mapping Program
Page Contact Information: Personnel
Page Last Modified: Thu 04 Apr 2024 03:52:49 PM MDT