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

The formation is composed of relatively soft grayish-red shale and olive-gray sandstone.

[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.

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.