The Nittany Arch or Nittany anticline is an

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 ...

geologic

formation Formation may refer to: Linguistics * Back-formation, the process of creating a new lexeme by removing or affixes * Word formation, the creation of a new word by adding affixes Mathematics and science * Cave formation or speleothem, a secondar ...

in the western part of the Ridge-and-Valley

physiographic province physiographic province is a geographic region with a characteristic geomorphology, and often specific subsurface rock type or structural elements. The continents are subdivided into various physiographic provinces, each having a specific characte ...

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 ...

of 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 ...

. The Nitany Arch is more than 100 miles (160 kilometers) long, stretching from Muncy to

Hollidaysburg Hollidaysburg is a borough (Pennsylvania), borough in and the county seat of Blair County, Pennsylvania, Blair County in the U.S. state of Pennsylvania. It is located on the Juniata River, south of Altoona, Pennsylvania, Altoona and is part of ...

, with a maximum width of approximately 9 miles (15 kilometers). 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 ...

, the

sedimentary rock Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at Earth's surface, followed by cementation. Sedimentation is the collective name for processes that cause these particles ...

layers in this area folded up, forming the Nittany Arch. The arch was an ancient 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 ...

. It has since eroded leaving its many rock layers exposed with the youngest rock layers at the foot of the

Allegheny Front The Allegheny Front is the major southeast- or east-facing escarpment in the Allegheny Mountains in southern Pennsylvania, western Maryland, eastern West Virginia, and western Virginia, USA. The Allegheny Front forms the boundary between the ...

. The more durable rock layers have left the surrounding sandstone ridges above the limestone valleys.

References

Anticlines Appalachian Mountains {{Pennsylvania-geologic-formation-stub

See also

References