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National Geologic Map Database
Map showing publication footprint
  • Usage in publication:
    • Cocalico shale*
  • Modifications:
    • Named
  • Dominant lithology:
    • Shale
    • Sandstone
    • Limestone
  • AAPG geologic province:
    • Appalachian basin
Publication:

Stose, G.W., and Jonas, A.I., 1922, The lower Paleozoic section in southeastern Pennsylvania: Washington Academy of Sciences Journal, v. 12, no. 5, p. 358-366.


Summary:

Named for exposures along Cocalico Creek, Lancaster Co., southeastern PA. Consists of dark-gray shale containing graptolites of Normanskill type and thin crinoidal limestone at base; gray, green, and purple slates and green impure sandstone above. Thickness is 1000 ft, more or less. Overlies Beekmantown limestone northeast of Lancaster. Age is Ordovician.

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


Map showing publication footprint
  • Usage in publication:
    • Cocalico Formation
  • Modifications:
    • Revised
  • AAPG geologic province:
    • Appalachian basin

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

Berg, T.M. (compiler), 1980, Geologic map of Pennsylvania: Pennsylvania Geological Survey State Map, 4th series, 1, scale 1:250,000


Summary:

The Cocalico Formation is probably closely related to the Hamburg sequence of PA. Consists of gray, phyllitic shale, maroon shale, and silty siliceous shale with some interbedded argillaceous and quartzose sandstone. Unit is of Ordovician age.

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


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

Geyer, A.R., and Wilshusen, J.P., 1982, Engineering characteristics of the rocks of Pennsylvania; environmental geology supplement to the State geologic map; 2nd edition, revised: Pennsylvania Geological Survey Environmental Geology Report, 4th series, no. 1, 300 p., Revision of McGlade, W.G., Geyer, A.R., and Wilshusen, J.P., 1972, "Engineering characteristics of the rocks of Pennsylvania," Pennsylvania Geol. Survey, 4th ser., Env. Geol. Rpt. EG 1, 200 p. (1st ed.)


Summary:

The Cocalico Formation is divided into two informal members [relative position of members not stated]. The shale member consists of gray, highly phyllitic, moderately well and thin-bedded shale with some interbedded red shale. The shale member is slightly resistant to weathering. The sandstone member consists of argillaceous and quartzose, well and thick-bedded sandstone that is highly resistant to weathering.

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


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

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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 ([ ]).