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Map showing publication footprint
  • Usage in publication:
    • Prettyboy Schist
  • Modifications:
    • Named
  • Dominant lithology:
    • Schist
  • AAPG geologic province:
    • Piedmont-Blue Ridge province
Publication:

Crowley, W.P., 1976, The geology of the crystalline rocks near Baltimore and its bearing on the evolution of the eastern Maryland Piedmont: Maryland Geological Survey Report of Investigations, no. 27, 40 p.


Summary:

Name Prettyboy Schist of Wissahickon Group is here proposed for the schists exposed in the vicinity of the dam at Prettyboy Reservoir. Unit consists of uniform, fine-grained plagioclase-chlorite-muscovite-quartz schist, commonly with magnetite and conspicuous albite porphyroblasts. Limonitized pyrite cubes occur locally. Overlies Pleasant Grove Schist (new); upper contact not stated. Age of Wissahickon Group and encompassing Glenarm Supergroup (both raised in rank in this report) is shown as Cambro-Ordovician(?).

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


Map showing publication footprint
  • Usage in publication:
    • Prettyboy Schist*
  • Modifications:
    • Revised
    • Age modified
  • AAPG geologic province:
    • Piedmont-Blue Ridge province
Publication:

Drake, A.A., Jr., 1994, The Soldiers Delight Ultramafite in the Maryland Piedmont, IN Drake, A.A., Jr., and Pavlides, Louis, Stratigraphic notes, 1993: U.S. Geological Survey Bulletin, 2076-A, 14 p.


Summary:

Pleasant Grove Schist here abandoned because it has been determined that Pleasant Grove was composed of sheared Mather Gorge Formation, Prettyboy Schist, and Marburg Formation. Age changed to Late Proterozoic and Early Cambrian.

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


Map showing publication footprint
  • Usage in publication:
    • Prettyboy Schist*
  • Modifications:
    • Areal extent
  • AAPG geologic province:
    • Piedmont-Blue Ridge province
Publication:

Southworth, Scott, 1996, Tectonic setting of the Martic Fault in Maryland, IN Brezinski, D.K., and Reger, J.P., eds., Part II, Research Papers; studies in Maryland geology; in commemoration of the centennial of the Maryland Geological Survey: Maryland Geological Survey Special Publication, no. 3, p. 205-221.


Summary:

Prettyboy Schist extended to PA following Howard (1994, unpub. Ph.D. thesis).

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


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

Asterisk (*) indicates published by U.S. Geological Survey authors.

"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 conflicts with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005, 2021). May be explained within brackets ([ ]).

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