The Mississippian Pocono Formation is a mapped bedrock unit in

Pennsylvania Pennsylvania (; ( Pennsylvania Dutch: )), officially the Commonwealth of Pennsylvania, is a state spanning the Mid-Atlantic, Northeastern, Appalachian, and Great Lakes regions of the United States. It borders Delaware to its southeast, ...

Maryland Maryland ( ) is a state in the Mid-Atlantic region of the United States. It shares borders with Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware and the Atlantic Ocean to ...

, and

West Virginia West Virginia is a state in the Appalachian, Mid-Atlantic and Southeastern regions of the United States.The Census Bureau and the Association of American Geographers classify West Virginia as part of the Southern United States while the Bur ...

, in the United States. It is also known as the Pocono Group in Maryland and West Virginia, and the upper part of the Pocono Formation is sometimes called the Burgoon Formation or Burgoon Sandstone in Pennsylvania. The Pocono is a major

ridge-former A cliff-former is a geological unit of bedrock that is more resistant to erosion than overlying or underlying strata and consequently produces outcrops with high slope angles. It is more or less equivalent to ''ridge-former'', and may be contrast ...

In the

Ridge-and-Valley Appalachians The Ridge-and-Valley Appalachians, also called the Ridge and Valley Province or the Valley and Ridge Appalachians, are a physiographic province of the larger Appalachian division and are also a belt within the Appalachian Mountains extending ...

of the eastern

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

The Pocono is also a lateral equivalent of the Purslane Sandstone in Maryland and West Virginia. D. Brezinski of Maryland Geological Survey recommended abandoning use of the term Pocono in Maryland in favor of "Purslane" in 1989.

Description

The Pocono is a dominantly gray color with

quartzitic Quartzite is a hard, non- foliated metamorphic rock which was originally pure quartz sandstone.Essentials of Geology, 3rd Edition, Stephen Marshak, p 182 Sandstone is converted into quartzite through heating and pressure usually related to tect ...

medium to coarse-grained

sandstones Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates) b ...

. The base of the Pocono Formation is marked by

conglomerate Conglomerate or conglomeration may refer to: * Conglomerate (company) * Conglomerate (geology) * Conglomerate (mathematics) In popular culture: * The Conglomerate (American group), a production crew and musical group founded by Busta Rhymes ** Co ...

Notable exposures

* The type section of the Burgoon Sandstone is in the valley of

Burgoon Run Burgoon is a village in Sandusky County, Ohio, United States. The population was 172 at the 2010 census. Geography Burgoon is located at (41.266832, -83.250024). According to the United States Census Bureau, the village has a total area of , ...

, above Kittanning Point,

Blair County, Pennsylvania Blair County is a county in the Commonwealth of Pennsylvania. As of the 2020 census, the population was 122,822. Its county seat is Hollidaysburg. The county was created on February 26, 1846, from parts of Huntingdon and Bedford counties. Blai ...

. * A spectacular exposure of the Purslane Sandstone (equivalent to the Pocono) is at the

I-68 Interstate 68 (I-68) is a Interstate Highway in the US states of West Virginia and Maryland, connecting I-79 in Morgantown, West Virginia, to I-70 in Hancock, Maryland. I-68 is also Corridor E of the Appalachian Development Highway Syste ...

road cut through

Sideling Hill Sideling Hill, also Side Long Hill, is a long, steep, narrow mountain ridge in the Ridge-and-Valley (or Allegheny Mountains) physiographic province of the Appalachian Mountains, located in Washington County in western Maryland and adjacent West ...

in Maryland.

Age

Relative age dating of the Pocono places it in the lower Mississippian period. The lower boundary is with the Spetchy Kopf Formation and

Huntley Mountain Formation The Huntley Mountain Formation is a late Devonian and early Mississippian mapped bedrock unit in Pennsylvania, in the United States. Description The formation is composed of relatively soft grayish-red shale and olive-gray sandstone. It is lo ...

. In South-central Pennsylvania, the Pocono often interfingers with the

Rockwell Formation The Rockwell Formation is a late Devonian and early Mississippian mapped bedrock unit in West Virginia, Maryland, and Pennsylvania, in the United States. Description The Rockwell Formation was described at its type section at Rockwell Run in We ...

.Berg, T.M., Edmunds, W.E., Geyer, A.R. and others, compilers, (1980). Geologic Map of Pennsylvania: Pennsylvania Geologic Survey, Map 1, scale 1:250,000.

Description

Notable exposures

Age

References

See also