The Huntley Mountain Formation is a late

Devonian The Devonian ( ) is a period (geology), geologic period and system (stratigraphy), system of the Paleozoic era (geology), era during the Phanerozoic eon (geology), eon, spanning 60.3 million years from the end of the preceding Silurian per ...

and early

Mississippian Mississippian may refer to: * Mississippian (geology), a subperiod of the Carboniferous period in the geologic timescale, roughly 360 to 325 million years ago * Mississippian cultures, a network of precontact cultures across the midwest and Easte ...

mapped bedrock unit in

Pennsylvania Pennsylvania, officially the Commonwealth of Pennsylvania, is a U.S. state, state spanning the Mid-Atlantic (United States), Mid-Atlantic, Northeastern United States, Northeastern, Appalachian, and Great Lakes region, Great Lakes regions o ...

, in the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

Description

The formation is composed of relatively soft grayish-red

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of Clay mineral, clay minerals (hydrous aluminium phyllosilicates, e.g., Kaolinite, kaolin, aluminium, Al2Silicon, Si2Oxygen, O5(hydroxide, OH)4) and tiny f ...

and olive-gray

sandstone Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...

. It is located in north central Pennsylvania.

Haystacks

The Haystacks are enigmatic mounds of sandstone that outcrop in Loyalsock Creek south of Dushore in Sullivan County. They are a single

bed A bed is a piece of furniture that is used as a place to sleep, rest, and relax. Most modern beds consist of a soft, cushioned mattress on a bed frame. The mattress rests either on a solid base, often wood slats, or a sprung base. Many beds ...

quartz Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The Atom, atoms are linked in a continuous framework of SiO4 silicon–oxygen Tetrahedral molecular geometry, tetrahedra, with each oxygen being shared between two tet ...

with an undulating upper surface with up to one meter relief. The origin of the mounds is debatable.

Notable Exposures

* The type section of the formation is at Huntley Mountain in

Lycoming County, Pennsylvania Lycoming County is a county in the Commonwealth of Pennsylvania. As of the 2020 census, the population was 114,188. Its county seat is Williamsport. The county is part of the North Central region of the commonwealth. Lycoming County compri ...

, on the mountainside just north of the village of Waterville. * Base of the

Loyalsock Creek Loyalsock Creek is a U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map, accessed August 8, 2011 tributary of the West Branch Susquehanna River located chiefly in Sullivan and Lycoming counties in ...

gorge in

Worlds End State Park Worlds End State Park is a Pennsylvania state park in Sullivan County, Pennsylvania. The park, nearly surrounded by Loyalsock State Forest, is in the Loyalsock Creek valley on Pennsylvania Route 154 in Forks and Shrewsbury Townships southeas ...

* Haystacks beds, also in Loyalsock Creek

Stratigraphy

Geologist William E. Edmunds argues that the Huntley Mountain Formation is laterally equivalent to 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 ...

(originally described in

West Virginia West Virginia is a mountainous U.S. state, state in the Southern United States, Southern and Mid-Atlantic (United States), Mid-Atlantic regions of the United States.The United States Census Bureau, Census Bureau and the Association of American ...

) and the Spechty Kopf Formation. He proposes that the

Pocono Formation The Mississippian Pocono Formation is a mapped bedrock unit in Pennsylvania, Maryland, and West Virginia, 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 somet ...

be reinstated as "the dominantly non-red, non-marine clastic sequence between the Catskill and

Mauch Chunk Formation The Mississippian Mauch Chunk Formation is a mapped bedrock unit in Pennsylvania, Maryland, and West Virginia. It is named for the township of Mauch Chunk, now known as borough of Jim Thorpe, Pennsylvania and for nearby Mauch Chunk Ridge where th ...

s", with the Huntley Mountain, Beckville, Burgoon, Rockwell, Mt. Carbon, and Spechty Kopf Formations demoted to the status of members of the Pocono Formation. Other workers support this interpretation.Lessing, Peter, Dean, S.L., and Kulander, B.R., 1992, Stratigraphy and structure of Meadow Branch synclinorium, West Virginia: Southeastern Geology, v. 32, no. 3, p. 166-174.

References

{{Chronostratigraphy of Pennsylvania Devonian System of North America Mississippian United States Sandstone formations of the United States Shale formations of the United States Devonian geology of Pennsylvania Geologic formations of Pennsylvania Devonian Pennsylvania

Description

Haystacks

Notable Exposures

Stratigraphy

See also

References