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National Geologic Map Database
Geologic Unit: Lemont
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Map showing publication footprint
  • Usage in publication:
    • Lemont argillaceous limestone member
  • Modifications:
    • Named
    • Biostratigraphic dating
  • Dominant lithology:
    • Limestone
  • AAPG geologic province:
    • Appalachian basin
Publication:

Butts, Charles, 1918, Geologic section of Blair and Huntingdon Counties, central Pennsylvania: American Journal of Science, 4th series, v. 46, p. 523-537.


Summary:

Named the Lemont argillaceous limestone member of the Carlim limestone for Lemont, Centre Co., central PA. Unit is a richly fossiliferous limestone forming top member of Carlim. Thickness is 0 to 105 feet. Underlies the Lowville limestone and correlates with the Crown Point limestone of NY. Fossils indicate that the Lemont is of Middle Ordovician (Chazyan) age.

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


Map showing publication footprint
  • Usage in publication:
    • Lemont Formation
  • Modifications:
    • Revised
    • Age modified
  • AAPG geologic province:
    • Appalachian basin
Publication:

Hunter, P.M., and Parizek, R.R., 1979, A structurally disturbed zone in central Pennsylvania; surface expression of a domain boundary?, IN Podwysocki, M.H., and Earle, J.L., eds., Proceedings of the second international conference on basement tectonics: International Conference on Basement Tectonics Proceedings, 2nd International Conference, Newark, DE, July 13-17, 1976, no. 2, p. 111-121.


Summary:

Revised the Lemont to the Lemont Formation and changed the age from Middle Ordovician to Late Ordovician (Cincinnatian). Formation includes (ascending) the Hatter Limestone Member, Snyder Limestone Member, Linden Hall Limestone Member, and Nealmont Limestone Member. Thickness is about 480 feet. Overlies the Clover Limestone and underlies the Salona Limestone.

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 ([ ]).