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The Huntley Mountain Formation is a late Devonian and early Mississippian mapped bedrock unit in Pennsylvania, in the United States.

Huntley Mountain Formation
Stratigraphic range: Late Devonian to Early Mississippian
Haystacks1 Loyalsock Creek Sullivan Co PA.jpg
The Haystacks of Loyalsock Creek in Laporte Township, Sullivan County, Pennsylvania are a quartzite bed of the Huntley Mountain Formation
UnderliesBurgoon Sandstone
Primarysandstone, shale
RegionAppalachian Mountains
Type section
Named forHuntley Mountain, Lycoming County, Pennsylvania
Named byBerg and Edmunds, 1978



Outcrop of Huntley Mountain Formation along old railroad bed parallel to Loyalsock Creek north of Laporte, Pennsylvania

The formation is composed of relatively soft grayish-red shale and olive-gray sandstone. It is located in north central Pennsylvania.[1][2][3]


The Haystacks are enigmatic mounds of sandstone that outcrop in Loyalsock Creek south of Dushore in Sullivan County. They are a single bed of quartz sandstone with an undulating upper surface with up to one meter relief. The origin of the mounds is debatable.[4]

Notable ExposuresEdit


Geologist William E. Edmunds argues that the Huntley Mountain Formation is laterally equivalent to the Rockwell Formation (originally described in West Virginia) and the Spechty Kopf Formation. He proposes that the Pocono Formation be reinstated as "the dominantly non-red, non-marine clastic sequence between the Catskill and Mauch Chunk Formations", with the Huntley Mountain, Beckville, Burgoon, Rockwell, Mt. Carbon, and Spechty Kopf Formations demoted to the status of members of the Pocono Formation.[5] Other workers support this interpretation.[6]


  1. ^ Berg, T.M. (1981). "Atlas of Preliminary Geologic Quadrangle Maps of Pennsylvania: Eagles Mere" (PDF). Pennsylvania Department of Conservation and Natural Resources, Bureau of Topographic and Geologic Survey. Retrieved 2008-05-21.
  2. ^ "Map 67: Tabloid Edition Explanation" (PDF). Pennsylvania Department of Conservation and Natural Resources, Bureau of Topographic and Geologic Survey.
  3. ^ Royer, Denise W. "Pennsylvania Trail of Geology, Worlds End State Park, Sullivan County, Geologic Features of Interest (Park Guide 12)" (PDF). Pennsylvania Department of Conservation and Natural Resources. Retrieved 2007-08-28.
  4. ^ The Haystacks, "Ricketts Folly," and The End of the World: Geology of the Glaciated Allegheny High Plateau, Sullivan, Luzerne, and Columbia Counties, Pennsylvania, 71st Annual Field Conference of Pennsylvania Geologists [1] (field trip guide book), J. D. Inners, G. M. Fleeger, eds., 2006
  5. ^ Edmunds, William E (1996). "Correlation Chart showing Suggested Revisions of Uppermost Devonian through Permian Stratigraphy, Pennsylvania" (PDF). Harrisburg: Pennsylvania Geological Survey, Fourth Series. Retrieved 2008-06-03.
  6. ^ 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.

See alsoEdit