Tussey Mountain is a

stratigraphic Stratigraphy is a branch of geology concerned with the study of rock layers (strata) and layering (stratification). It is primarily used in the study of sedimentary and layered volcanic rocks. Stratigraphy has three related subfields: lithostra ...

ridge in central

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, ...

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 territori ...

, trending east of the Bald Eagle, Brush, Dunning and Evitts Mountain ridges. Its southern foot just crosses the

Mason–Dixon line The Mason–Dixon line, also called the Mason and Dixon line or Mason's and Dixon's line, is a demarcation line separating four U.S. states, forming part of the borders of Pennsylvania, Maryland, Delaware, and West Virginia (part of Virginia ...

near

Flintstone, Maryland Flintstone is an unincorporated community and census-designated place (CDP) in Allegany County, Maryland, United States. As of the 2010 census it had a population of 177. It is part of the Cumberland, MD-WV Metropolitan Statistical Area. Flints ...

, running north 130 km (80 mi) to the Seven Mountains of central Pennsylvania, near Tusseyville, making it one of the longest named ridges in this section of 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 ...

. The ridge line separates

Morrison Cove Morrisons Cove (also referred to as Morrison Cove or Morrison's Cove), is an eroded anticlinal valley in Blair and Bedford counties of central Pennsylvania, United States, extending from Evitts Mountain near New Enterprise, north to the Frankstown ...

from the Woodcock Valley and Friends Cove from the Black Valley. Tussey Mountain lies in, and the ridge line forms parts of the borders of,

Centre Center or centre may refer to: Mathematics * Center (geometry), the middle of an object * Center (algebra), used in various contexts ** Center (group theory) ** Center (ring theory) * Graph center, the set of all vertices of minimum eccentri ...

, Blair,

Bedford Bedford is a market town in Bedfordshire, England. At the 2011 Census, the population of the Bedford built-up area (including Biddenham and Kempston) was 106,940, making it the second-largest settlement in Bedfordshire, behind Luton, whilst ...

and Huntingdon counties. The Flintstone Creek runs around the southern end of the mountain in Maryland. North of there, small streams run through deep gorges, the Sweet Root and Rainsburg Gaps, near Martin Hill. At Everett the

Pennsylvania Turnpike The Pennsylvania Turnpike (Penna Turnpike or PA Turnpike) is a toll highway operated by the Pennsylvania Turnpike Commission (PTC) in the U.S. state of Pennsylvania. A controlled-access highway, it runs for across the state. The turnpike's w ...

U.S. Route 30 U.S. Route 30 or U.S. Highway 30 (US 30) is an east–west main route in the system of the United States Numbered Highways, with the highway traveling across the northern tier of the country. With a length of , it is the third longest ...

, and the abandoned Huntingdon and Broad Top Mountain Railroad follow the Raystown Branch Juniata River through a deep

water gap A water gap is a gap that flowing water has carved through a mountain range or mountain ridge and that still carries water today. Such gaps that no longer carry water currents are called wind gaps. Water gaps and wind gaps often offer a prac ...

known as

The Narrows __NOTOC__ The Narrows is the tidal strait separating the boroughs of Staten Island and Brooklyn in New York City, United States. It connects the Upper New York Bay and Lower New York Bay and forms the principal channel by which the Hudson Riv ...

. The Yellow Creek runs through Loysburg Gap at Loysburg, Pennsylvania. Maple Run Road passes through a

wind gap A wind gap (or air gap) is a gap through which a waterway once flowed that is now dry as a result of stream capture. A water gap is a similar feature, but one in which a waterway still flows. Water gaps and wind gaps often provide routes which ...

near Pulpit Hill and Coot Hill, heading west to Woodbury. Pennsylvania Route 164 runs east out of Martinsburg, and climbs the west slope with a switchback before crossing the crest. The Frankstown Branch Juniata River runs north along the west foot of the ridge before turning east along

U.S. Route 22 U.S. Route 22 (US 22) is a west–east route and is one of the original United States highways of 1926, running from Cincinnati, Ohio, at US 27, US 42, US 127, and US 52 to Newark, New Jersey, at U.S. Route 1/9 in the Newark Airport Intercha ...

at Water Street, the river, road, and rail (abandoned PRR

Petersburg Branch Petersburg, or Petersburgh, may refer to: Places Australia *Petersburg, former name of Peterborough, South Australia Canada * Petersburg, Ontario Russia *Saint Petersburg, sometimes referred to as Petersburg United States * Peterborg, U.S. Vir ...

) crossing the ridge line through a water gap. The

Little Juniata River The Little Juniata River, sometimes called the "Little J," is a U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map, accessed August 8, 2011 tributary of the Juniata River in the Susquehanna River wa ...

passes through a nearby water gap at Spruce Creek along with the former Pennsylvania Railroad Main Line, which tunnels through a spur of the mountain to cut across a loop in the river. Galbraith Run passes through Galbraith Gap near the north end of the ridge, adjacent to the Tussey Mountain Ski Area in Boalsburg. The Tussey Mountain Ridge is popular with soaring birds and glider pilots ridge soaring along its slopes. This ridge is part of a chain of ridges that stretch south to

Tennessee Tennessee ( , ), officially the State of Tennessee, is a landlocked state in the Southeastern region of the United States. Tennessee is the 36th-largest by area and the 15th-most populous of the 50 states. It is bordered by Kentucky to th ...

. Tussey Mountain has been designated a Pennsylvania Important Bird Area (IBA), based primarily on its importance as a spring raptor migration site, but also as a long corridor of

intact forest An intact forest landscape (IFL) is an unbroken natural landscape of a forest ecosystem and its habitat–plant community components, in an extant forest zone. An IFL is a natural environment with no signs of significant human activity or habitat f ...

habitat, over 50% of which is publicly owne

It is one of the best sites in the eastern United States for viewing the migration of the golden eagle. Pennsylvania's longest footpath, Mid State Trail, is atop or closely parallels Tussey Mountain for nearly its entire length. In Blair County, Tussey Mountain is sometimes called Huntingdon Mountain, as one reaches Huntingdon by crossing it going east. Conversely, in some parts of Huntingdon County it is called

Williamsburg Mountain Williamburg Mountain is a high "S" bend in the ridge of Tussey Mountain, in the Ridge-and-Valley Province of the Appalachian Mountains in central Pennsylvania. The name "Williamsburg Mountain" is a local reference, after the town of Williamsb ...

as one reaches Williamsburg by crossing it going west.

Pennsylvania State Game Lands Number 118 The Pennsylvania State Game Lands Number 118 are Pennsylvania State Game Lands in Blair and Huntingdon counties in Pennsylvania in the United States, providing hunting, bird watching, and other activities. Geography Game Lands Number 118 runs al ...

is located along Tussey Mountain in Blair and Huntingdon Counties.https://viewer.nationalmap.gov/advanced-viewer/ The National Map, retrieved 12 November 2018Pennsylvania State Game Lands Number 118
retrieved 12 November 2018

Geology

Tussey Mountain is in the Ridge and Valley province of the

Appalachian Mountains The Appalachian Mountains, often called the Appalachians, (french: Appalaches), are a system of mountains in eastern to northeastern North America. The Appalachians first formed roughly 480 million years ago during the Ordovician Period. They ...

. Brush Mountain, Mount Nittany and Bald Eagle Mountain ridges, are part of the same

Paleozoic The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon. The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838 by combining the Greek words ''palaiós'' (, "old") and ' ...

anticline In structural geology, an anticline is a type of fold that is an arch-like shape and has its oldest beds at its core, whereas a syncline is the inverse of an anticline. A typical anticline is convex up in which the hinge or crest is the ...

rock formation consisting of older

Ordovician The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya. T ...

Bald Eagle Formation The Ordovician Bald Eagle Formation is a mapped bedrock unit in central Pennsylvania, USA. It is a ridge-forming unit in the Appalachian Mountains. Description The Bald Eagle is defined as a gray to olive-gray and grayish-red, fine to coarse-gra ...

Sandstone 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 ...

and Juniata Formation Shale, and younger Silurian Tuscarora Formation

Quartzite 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 tec ...

. During the

Appalachian orogeny The Alleghanian orogeny or Appalachian orogeny is one of the geological mountain-forming events that formed the Appalachian Mountains and Allegheny Mountains. The term and spelling Alleghany orogeny was originally proposed by H.P. Woodward in 195 ...

, these layers folded up with the underlying and overlying layers into the Nittany Arch. The arch was a Himalayan scale mountain that towered above what is now

Nittany Valley Nittany Valley is an eroded anticlinal valley located in Centre County, Pennsylvania. It is separated from the Bald Eagle Valley by Bald Eagle Mountain and from Penns Valley by Mount Nittany. The valley is closed to the north by a high plateau t ...

, where the oldest rock layers from deep within the

eroded Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is disti ...

mountain are now exposed. The Tuscarora Quartzite is more resistant to erosion than Bald Eagle Sandstone, and both are more durable than the Juniata Shale sandwiched in-between. Softer rock layers on either side of these eroded, leaving the double crested Tussey Mountain ridge, with a depression between the higher eastern and lower western ridge lines found on the northern section of the ridge. Since the rock layers on these ridges slope down to the east, the Tuscarora Formation underlies the higher crest, where it protected the east slope from erosion. Drainage from the upper slope has cut a series of small ravines in the lower ridge line, leaving a terraced lower slope in the Bald Eagle Formation. On the neighboring Bald Eagle, Brush, and Dunning Mountain ridges to the west that formed the opposite side of the ancient mountain, the same three rock layers are exposed in reverse order, with the oldest rocks in-between, near the hinge of the fold.Description of the Geology of Centre County, Pennsylvania
libraries.psu.edu

References

{{commonscat Ridges of Pennsylvania Allegheny Mountains Ridges of Blair County, Pennsylvania Landforms of Centre County, Pennsylvania Ridges of Huntingdon County, Pennsylvania Ridges of Bedford County, Pennsylvania Water gaps of Pennsylvania Wind gaps of the United States

Geology

See also

References