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National Geologic Map Database
Geologic Unit: Pokejoy
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Map showing publication footprint
  • Usage in publication:
    • Pokejoy Member
  • Modifications:
    • Named
  • Dominant lithology:
    • Shale
    • Limestone
  • AAPG geologic province:
    • Appalachian basin
Publication:

Hasson, K.O., and Dennison, J.M., 1974, The Pokejoy Member, a new subdivision of the Mahantango Formation (Middle Devonian) in West Virginia, Maryland, and Pennsylvania: West Virginia Academy of Science, v. 46, no. 1, p. 78-86.


Summary:

A lithologically distinct interval within the Mahantango Formation consisting of a basal limestone and very fossiliferous, calcitic shale or coral biostromal, silty limestone here named Pokejoy Member for exposures at Pokejoy Run in Mineral Co., WV, where unit is 10.6 ft (3.3 m) thick. At type, basal limestone (0.6 ft) is argillaceous, medium dark gray, fossiliferous and weathers pale yellowish brown. Middle shale (9.5 ft) is silty, calcitic, fossiliferous, thickly laminated and weathers light olive gray, chippy to lumpy. Upper limestone bed (0.5 ft) is argillaceous, medium dark gray, fossiliferous and weathers pale yellowish brown. Unit occurs 32 to 216 ft below the Tully Limestone in parts of West Virginia, western Maryland, and south-central Pennsylvania. Reference section is designated in Allegany Co., MD, where unit is exposed on southeast side of U.S. Rte 40, 0.4 mi southwest of Wolfe Mill. Biostromal facies is best seen in reference section in Mineral Co., WV, along north side of U.S. Rte 50, 0.3 mi west of Burlington. Underlies unnamed silty, fossiliferous, thickly laminated shale at top of Mahantango, which in turn underlies Burket Member of Harrell Shale. Overlies Clearville Siltstone Member. Age is Middle Devonian.

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


Map showing publication footprint
  • Usage in publication:
    • Pokejoy Member*
  • Modifications:
    • Biostratigraphic dating
  • AAPG geologic province:
    • Appalachian basin
Publication:

Harris, A.G., Stamm, N.R., Weary, D.J., Repetski, J.E., Stamm, R.G., and Parker, R.A., 1994, Conodont color alteration index (CAI) map and conodont-based age determinations for the Winchester 30' x 60' quadrangle and adjacent area, Virginia, West Virginia, and Maryland: U.S. Geological Survey Miscellaneous Field Studies Map, MF-2239, 1 sheet, 40 p., scale 1:100,000 [http://ngmdb.usgs.gov/Prodesc/proddesc_294.htm]


Summary:

Conodont biostratigraphy indicates that the Pokejoy Member of the Mahantango Formation in the Winchester 30 X 60 minute quadrangle is of Middle Devonian (Givetian) age. Conodonts indicative of the P. VARCUS and S. HERMANNI-P. CRISTATUS Zones were recovered.

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 ([ ]).