The Reading Prong is a physiographic subprovince of the New England Uplands section of the New England province of the Appalachian Highlands. The prong consists of

mountain A mountain is an elevated portion of the Earth's crust, generally with steep sides that show significant exposed bedrock. Although definitions vary, a mountain may differ from a plateau in having a limited summit area, and is usually higher t ...

s made up of crystalline

metamorphic rock Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock ( protolith) is subjected to temperatures greater than and, often, elevated pressure of or more, caus ...

Location

The Reading Prong stretches from near

Reading, Pennsylvania Reading ( ; ) is a city in Berks County, Pennsylvania, United States, and its county seat. The city had a population of 95,112 at the 2020 United States census, 2020 census and is the List of municipalities in Pennsylvania, fourth-most populous ...

, through the

Lehigh Valley The Lehigh Valley () is a geography, geographic and urban area, metropolitan region formed by the Lehigh River in Lehigh County, Pennsylvania, Lehigh and Northampton County, Pennsylvania, Northampton counties in eastern Pennsylvania. It is a co ...

in eastern

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 ...

northern

New Jersey New Jersey is a U.S. state, state located in both the Mid-Atlantic States, Mid-Atlantic and Northeastern United States, Northeastern regions of the United States. Located at the geographic hub of the urban area, heavily urbanized Northeas ...

and into southern New York. It reaches its northern terminus in

Connecticut Connecticut ( ) is a U.S. state, state in the New England region of the Northeastern United States. It borders Rhode Island to the east, Massachusetts to the north, New York (state), New York to the west, and Long Island Sound to the south. ...

. In Pennsylvania, the Reading Prong is referred to as South Mountain while in New Jersey and New York the mountains of the subprovince are referred to as the New York – New Jersey Highlands. Near the

Hudson Valley The Hudson Valley or Hudson River Valley comprises the valley of the Hudson River and its adjacent communities in the U.S. state of New York (state), New York. The region stretches from the Capital District (New York), Capital District includi ...

, the term

Hudson Highlands The Hudson Highlands are mountains on both sides of the Hudson River in New York (state), New York state lying primarily in Putnam County, New York, Putnam County on its east bank and Orange County, New York, Orange County on its west. They conti ...

is often used. The portion of the prong that enters Connecticut is known as the Housatonic Highlands.

Relation to other divisions of the New England Uplands

There are two subsections of the New England Uplands in addition to the Reading Prong. A prong of the same rock belt extends from the Hudson Highlands south to

New York City New York, often called New York City (NYC), is the most populous city in the United States, located at the southern tip of New York State on one of the world's largest natural harbors. The city comprises five boroughs, each coextensive w ...

along the

Hudson River The Hudson River, historically the North River, is a river that flows from north to south largely through eastern New York (state), New York state. It originates in the Adirondack Mountains at Henderson Lake (New York), Henderson Lake in the ...

. This region is often referred to as the Manhattan Prong. Staten Island Serpentinite is a southward extension of the New England Uplands.

Geology

The Reading Prong is part of the

Precambrian The Precambrian ( ; or pre-Cambrian, sometimes abbreviated pC, or Cryptozoic) is the earliest part of Earth's history, set before the current Phanerozoic Eon. The Precambrian is so named because it preceded the Cambrian, the first period of t ...

basement which is discontinuously exposed in the north-central Appalachians. The rocks that make up the prong consist of diverse

gneiss Gneiss (pronounced ) is a common and widely distributed type of metamorphic rock. It is formed by high-temperature and high-pressure metamorphic processes acting on formations composed of igneous or sedimentary rocks. This rock is formed under p ...

es. The New England Province and the Blue Ridge province share many geological similarities, and some experts consider the Reading Prong merely a continuation of the

Blue Ridge Mountains The Blue Ridge Mountains are a Physiographic regions of the United States, physiographic province of the larger Appalachian Highlands range. The mountain range is located in the Eastern United States and extends 550 miles southwest from southern ...

, which reach their northern terminus at South Mountain near

Harrisburg, Pennsylvania Harrisburg ( ; ) is the capital city of the U.S. commonwealth of Pennsylvania and the seat of Dauphin County. With a population of 50,099 as of 2020, Harrisburg is the ninth-most populous city in Pennsylvania. It is the larger of the two pr ...

. In the gap between the Blue Ridge and the Reading Province, the two mountainous regions descend into the Appalachian

Piedmont Piedmont ( ; ; ) is one of the 20 regions of Italy, located in the northwest Italy, Northwest of the country. It borders the Liguria region to the south, the Lombardy and Emilia-Romagna regions to the east, and the Aosta Valley region to the ...

. Together, the Blue Ridge province and the New England province are often referred to as the Crystalline Appalachians. Rocks of the Reading Prong are characterized by elevated concentrations of

uranium Uranium is a chemical element; it has chemical symbol, symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Ura ...

, the decay of which produces gaseous

radon Radon is a chemical element; it has symbol Rn and atomic number 86. It is a radioactive noble gas and is colorless and odorless. Of the three naturally occurring radon isotopes, only Rn has a sufficiently long half-life (3.825 days) for it to b ...

, a potentially hazardous source of indoor contamination in structures constructed on the prong.Critical Geologic Features-Allamuchy Township
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Mountains of the Reading Prong

Housatonic Highlands (north to south)

East Hudson Highlands (north to south)

* Sour Mountain *

Beacon Mountain Beacon Mountain, locally Mount Beacon, is the highest peak of Hudson Highlands, located south of Beacon, New York, City of Beacon, New York (state), New York, in the Fishkill (town), New York, Town of Fishkill. Its two summits rise above the Hud ...

Scofield Ridge Scofield may refer to: * Scofield (surname), a surname * Scofield, Michigan, an unincorporated community * Scofield, Utah, a very small town ** Scofield Mine disaster, when a coal mine exploded near the town in May 1900 ** Scofield Reservoir, ...

* North Sugarloaf * Breakneck Ridge * Bull Hill, aka Mt. Taurus * South Redoubt and North Redoubt * Sugarloaf Hill * White Rock * Canada Hill * Anthony's Nose

West Hudson Highlands (north to south)

* Storm King Mountain *

Crow's Nest A crow's nest is a structure in the upper part of the main mast of a ship or a structure that is used as a lookout point. On ships, this position ensured the widest field of view for lookouts to spot approaching hazards, other ships, or land b ...

* Popolopen Torne * Bear Mountain * West Mountain * Bald Mountain * Dunderberg Mountain

New Jersey Highlands (north to south)

* Pochuck Mountain * Maple Hill * Wawayanda Mountain * Sterling Hill * Hamburg Mountain * Sparta Mountain * Lookout Mountain * Allamuchy Mountain * Hackettstown Mountain * Danville Mountain * Watnong Mountain * High Rock Mountain * Jenny Jump Mountain * Mount Mohepinoke * Baldpate Mountain * County House Mountain * Mount No More * Scotts Mountain * Oxford Mountain * Marble Mountain * Upper Pohatcong Mountain * Pohatcong Mountain * Silver Hill * Musconetcong Mountain

Reading Prong of Pennsylvania (north to south)

* Chestnut Hill * Morgan Hill * Hexenkopf Hill * Christines Hill * Pektor Hill * Focht Hill * Kirchberg * Swoveberg * Kohlberg * Lehigh Mountain * Saucon Hill * Applebutter Hill * South Mountain

References

{{authority control Appalachian Mountains Geology of New Jersey Geology of New York (state) Geology of Pennsylvania