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Map showing publication footprint
  • Usage in publication:
    • Centennial School member
  • Modifications:
    • Named
  • Dominant lithology:
    • Sandstone
    • Shale
  • AAPG geologic province:
    • Appalachian basin
Publication:

Map showing publication footprint
  • Usage in publication:
    • Centennial School Member
  • Modifications:
    • Not used
  • AAPG geologic province:
    • Appalachian basin
Publication:

Thompson, A.M., 1970, Lithofacies and formation nomenclature in Upper Ordovician stratigraphy, central Appalachians, IN Note and Discussion: Geological Society of America Bulletin, v. 81, no. 4, p. 1255-1260.


Summary:

Attempts to apply member status to subdivisions of drab Bald Eagle and red Juniata Formations reveal inconsistencies. Thicknesses of Centennial School and Spring Mount Members of Eagle Formation and East Waterford Member of Juniata Formation fluctuate considerably and randomly in very short geographic distances. In addition, at several locations, drab shale is found above the massive sandstones of Spring Mount Member. They are not assignable to Spring Mount Member on lithologic basis, but they are not red so they cannot be assigned to Juniata either. Similarly, red sandstones and shales are found beneath East Waterford Member. They are not East Waterford lithology, but they cannot be assigned to Bald Eagle because of color. Proposal is to do away with formal member names and switch to lithofacies nomenclature for subdivisions of these formation. [Centennial School Member is not formally abandoned in this report.]

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 ([ ]).