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National Geologic Map Database
Geologic Unit: Forge Union
Map showing publication footprint
  • Usage in publication:
    • Forge Union Member
  • Modifications:
    • Named
  • Dominant lithology:
    • Dolomite
  • AAPG geologic province:
    • Appalachian basin
Publication:

Spelman, A.R., 1966, Stratigraphy of Lower Ordovician Nittany Dolomite in central Pennsylvania: Pennsylvania Geological Survey General Geology Report, 4th series, no. 47, 187 p.


Summary:

Named the Forge Union Member of the Nittany Dolomite in central PA as the lowest member of the formation. Consists of fine crystalline, structureless to slightly laminated dolomite containing sand-size and silt-size quartz grains. Thickness is 580 feet at Bellefonte. Overlies the Stonehenge Limestone or Larke Dolomite and underlies the Shoenberger Member of the Nittany. The Forge Union is of Early Ordovician age.

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 ([ ]).