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National Geologic Map Database
Map showing publication footprint
  • Usage in publication:
    • Old Port Formation
  • Modifications:
    • Named
  • Dominant lithology:
    • Sandstone
    • Chert
    • Limestone
    • Shale
  • AAPG geologic province:
    • Appalachian basin
Publication:

Conlin, R.R., and Hoskins, D.M., 1962, Geology and mineral resources of the Mifflintown quadrangle, Pennsylvania: Pennsylvania Geological Survey Topographic and Geologic Atlas, 4th series, 126, 46 p., scale 1:24,000


Summary:

In Mifflintown quad and adjacent areas, Lower Devonian sequence, previously assigned to Helderberg and Oriskany Groups, now considered one rock unit here named Old Port Formation. Unit consists essentially of thin quartz sandstone (Ridgeley Member) at top; underlain by chert and cherty limestone with varying thickness of shale interbeds. Thickness 150 to 190 ft in study area. Contact with underlying Keyser Formation is gradational. Contact with overlying Onondaga Formation is sharp.

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


Map showing publication footprint
  • Usage in publication:
    • Old Port Formation*
  • Modifications:
    • Revised
  • AAPG geologic province:
    • Appalachian basin
Publication:

Taylor, A.R., 1977, Geology and mineral resources of the Lock Haven 7.5-minute quadrangle, Clinton and Lycoming Counties, Pennsylvania: Pennsylvania Geological Survey Topographic and Geologic Atlas, 4th series, 124a, 118 p.


Summary:

Old Port Formation is divided into (ascending) Shriver Chert and Ridgeley Sandstone Members (reduced in rank). Age is Early Devonian.

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


Map showing publication footprint
  • Usage in publication:
    • Old Port Formation*
  • Modifications:
    • Overview
  • AAPG geologic province:
    • Appalachian basin
Publication:

Wood, C.R., 1980, Summary groundwater resources of Centre County, Pennsylvania: Pennsylvania Geological Survey Water Resource Report, 4th series, no. 48, 60 p.


Summary:

Lower Devonian Old Port Formation is divided in descending order into four members in central PA according to the usage of the Pennsylvania Geological Survey: Ridgeley, Shriver, Corriganville, and New Creek Members. Old Port underlies the Onondaga Formation and overlies the Keyser Formation.

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


Map showing publication footprint
  • Usage in publication:
    • Old Port Formation
  • Modifications:
    • Overview
  • AAPG geologic province:
    • Appalachian basin
Publication:

Faill, R.T., Glover, A.D., and Way, J.H., 1989, Geology and mineral resources of the Blandburg, Tipton, Altoona, and Bellwood quadrangles, Blair, Cambria, Clearfield and Centre Counties, Pennsylvania: Pennsylvania Geological Survey Topographic and Geologic Atlas, 4th series, 86, 209 p., scale 1:24,000 and 1:48,000


Summary:

Name encompasses many earlier terms such as Shriver, Ridgeley, Coeymans, New Scotland, Mandata, Helderberg, Oriskany, and Corriganville, which generally could not be separately mapped throughout the area. Name Old Port has been used throughout the Valley and Ridge province from east-central to southern PA. In the mapped area, the Old Port is composed of a lower limestone (7 m) and the Mandata (27 m), Shriver (26 m), and Ridgeley (7 m) Members. Unit is predominantly a cherty limestone, calcareous shale, argillaceous limestone, and calcareous sandstone in ascending order. Best exposures of the three lower members are in the old quarries in Tyrone west of Sink Run and along U.S. Rte 22, 2 km southwest of Frankstown. The best exposure of the Ridgeley is also in Tyrone, just west of the east edge of the Tipton quad.

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 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 ([ ]).