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National Geologic Map Database
Geologic Unit: Guymard
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Map showing publication footprint
  • Usage in publication:
    • Guymard quartzite
  • Modifications:
    • Named
  • Dominant lithology:
    • Quartzite
  • AAPG geologic province:
    • Appalachian basin
Publication:

Bryant, W.L., 1926, On the structure of Palaeaspis and on the occurrence in the United States of fossil fishes belonging to the family Pteraspidae: American Philosophical Society Proceedings, v. 65, no. 4, p. 256-271.


Summary:

Named the Guymard quartzite for Guymard, near Otisville, Orange Co., NY. Name is attributed to a Professor van Ingen. Consists of over 100 ft of gray, olive, and reddish quartzite. The Guymard overlies the Shawangunk grit and underlies rocks characteristic of the Longwood shale. Unit is of Silurian age.

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


Map showing publication footprint
  • Usage in publication:
    • Guymard†
  • Modifications:
    • Abandoned
  • AAPG geologic province:
    • Appalachian basin
Publication:

Epstein, J.B., 1993, Stratigraphy of Silurian rocks in Shawangunk Mountain, southeastern New York, including a historical review of nomenclature, IN Evolution of sedimentary basins; Appalachian basin: U.S. Geological Survey Bulletin, 1839-L, p. L1-L40.


Summary:

Rocks previously called Guymard Quartzite are considered to be the contact interval between the Shawangunk Formation and the Wurtsboro Tongue of the Bloomsburg Red Beds. The red bed within this interval is placed in the Shawangunk. Since these rocks can bed placed within the Shawangunk and Bloomsburg, the Guymard is abandoned.

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


For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.

Asterisk (*) indicates usage by the U.S. Geological Survey. Other usages by state geological surveys.

"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 does not conform with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005). This may be explained within brackets ([ ]).