Watchung Mountains

Watchung Mountains
Wach Unks
Range
Garret Mountain and Mount Cecchino seen from High Mountain in Wayne, New Jersey.
Country	United States of America
State	New Jersey
Highest point	High Mountain (Preakness Range)
- elevation	879 ft (268 m)
- coordinates	40°58′12.26″N 74°11′54.08″W / 40.9700722°N 74.1983556°W / 40.9700722; -74.1983556
Length	40 mi (64 km), north–south
Geology	extrusive igneous, trap rock
Period	Triassic/Jurassic

The Watchung Mountains are a group of three long low ridges of volcanic origin, between 400 ft. (122 m) and 500 ft. (152 m) high, lying parallel to each other in northern New Jersey in the United States. The mountains are known for their numerous scenic vistas overlooking the New York City and New Jersey skylines, as well as their isolated ecosystems containing rare plants, endangered wildlife, and globally imperiled traprock glade communities.^[1][2] The ridges traditionally contained the westward spread of urbanization, forming a significant geologic barrier on the piedmont west of the Hudson River. However, in many places the mountains have become sinuous islands of natural landscape within the suburban sprawl covering much of northeastern New Jersey. Parks and preserves dot the highest parts of the mountains, providing outdoor recreational opportunities to one of the most densely populated regions of the nation.

Geography

The ridges, known as Orange or First Watchung Mountain (the southeastern ridge) and Preakness or Second Watchung Mountain (the northwestern ridge), stretch for approximately 40 miles (64 km) from Somerville (in Somerset County) in the southwest to Paterson (in Passaic County) in the northeast. The discontinuous ridge formed by Long Hill, Riker Hill, Hook Mountain and Packanack Mountain is sometimes referred to as Third Watchung Mountain and lies on the northwestern side of Second Watchung. The basalt sill that forms First Watchung Mountain also extends well within Bergen County and emerges near the New York border as the 752 ft Campgaw Mountain, technically the most northern part of the Watchungs.^[3][4]

Ranges and ridges of the Watchungs

In addition to the three main ridges of the Watchungs, a smaller fourth ridge exists south of Morristown and west of Third Watchung Mountain.^[5] While attaining elevations over 400 ft, the ridge lacks topographic prominence, only rising to about 100 ft above the surrounding terrain. Only one portion of the ridge is named, a southern section underlying Harding Township known as Lees Hill.

Though the Watchungs are commonly described in terms of their east-west ridge arrangement, they are also divided into smaller mountain ranges, as well as various named ridges.

Notable ranges and ridges of the Watchungs from north to south include:

• Campgaw Mountain, the northernmost ridge of the Watchungs which also contains the fourth and seventh tallest peaks
• The Preakness Range, featuring the three tallest peaks of the Watchungs
• Goffle Hill, a 6-mi long ridge flanking the eastern side of the Preakness Range north of the Passaic River.
• The Newark Mountains, the historical range containing the ridges of First & Second Watchung Mountain south of the Passaic River.

Noteworthy summits of the Watchungs include High Mountain, Beech Mountain, and Mount Cecchino in Wayne, which stand at 879 ft (268m), 869 ft (265m) and 755 ft (230m) above sea level. Other notable summits are Garret Mountain in Paterson and the Hilltop in Verona, Cedar Grove, and North Caldwell.

History

Trees in the Watchung Reservation between the first and second ridges

The original inhabitants of the Watchungs, the Lenape, referred to the mountains as the Wach Unks, or ‘high hills’.^[6][7] Evidence of the Lenape presence in the Watchungs can be seen in the numerous camps sites that have been uncovered, mainly along the rivers coursing through mountains and in the small caves abundant in the volcanic rock. It is thought the Lenape favored the Watchungs for their profusion of natural resources, including abundant freshwater rivers and streams, a variety of forests, and plentiful fish and game.^[8]

With the arrival of Europeans, the same resources that sustained the indigenous peoples served settlers. Perhaps most importantly, the rivers and streams of the Watchungs supported grain, grist, and saw mills.^[9] Later, the energy of these rivers would be harnessed for industry, most notably at the Great Falls of the Passaic River, where mechanical and hydroelectric systems exploited the energy of water falling over the face of First Watchung Mountain.^[10]

Outside of providing gradation to rivers and streams, the height of the Watchungs has proven useful for other reasons.

• During the Revolutionary War, General George Washington used the protection of the Watchung mountains to erect the first and second Middlebrook encampment. This position on the high ground also allowed him to monitor the area between Perth Amboy and New Brunswick and to identify and disturb British movements between New York City and Philadelphia.^[11]
• In the twentieth century, the Hilltop in Verona – the highest point in Essex County – served as the site of a sanatorium for tuberculosis sufferers. The county hospital was built there because the high elevation provided clean, mountain air away from the cities to the east.
• At the height of the Cold War, Campgaw Mountain was selected to house a Nike missile base. Installed on the mountain between 1955 and 1971, the base’s missiles served to guard New York City’s air space, standing by to intercept nuclear armed Soviet bombers. The facility was ultimately abandoned with the advent of intercontinental ballistic missiles.^[12]

Geology

Extruding onto the surface as basalt lava flows 185 million years ago, the Watchung Mountains formed within the Newark Basin, a prehistoric rift valley which was active near or along the rift which ultimately tore North America and Africa apart, forming the Atlantic Ocean. The parallel ridges took shape as lava seeped through linear faults created during the rifting process.

When the rift underlying the Newark Basin failed during the early Jurassic, the mountains ceased growing. Initially, the lava flows did not rise significantly above the surrounding the land. However, the Watchungs are composed of highly erosion resistant and mineral-rich mafic stone known as traprock. As a result, millions of years of erosion lowered the easily worked sandstone and shale terrain surrounding the lava flows, turning the Watchung basalts into elevated ridges.^[13]

Because the majority of the Watchung Mountains are composed of extrusive igneous rock, they display characteristic columnar jointing and stacked lava flows. These same features can be seen in the Palisades Sill a dozen miles to the east, which formed around the same time as the Watchungs, probably from the same magma. However, unlike in the Watchungs, much of the molten material which formed The Palisades cooled before reaching the surface, becoming an intrusive feature.^[6]

Water flows over a traprock surface in the Watchungs

It is probable that the magma which generated the Watchungs and the Palisades also formed the intrusive igneous Sourland Mountain in Central New Jersey, as well as series of smaller outlying volcanic ridges in the region. Additionally, Cushetunk Mountain, a ring-shaped volcanic mountain between Sourland Mountain and the Watchungs, may be of the same geologic lineage.

The Metacomet Mountains in the Connecticut River Basin, another aborted rift valley, came into extistance around the same time as the Watchungs, also through extrusive eruptions. While non-contiguous, the two ranges can be considered geologic cousins, having formed under similar circumstances during the rifting of Pangaea. The same erosive forces which elevated the Watchungs also served in part to raise the Metacomets.^[13]

Mineralogy

The Watchungs are principally composed of volcanic basalt, which has historically been used in railroad beds and road construction. In addition to this, the mountains are in many places underlain by red and white sandstone which has at times been used in building construction. Mica and calcareous spar often accompany these sandstone beds.

An ancient lava front in the Watchungs baring embedded agate and quartz nodules

Due to the volcanic nature of the Watchungs, zeolites, including prehnite, analcime, and stilbite, which form from a reaction of mafic rocks in alkaline environments, can be found along exposed ridge lines. Agate, primarily in the form of chalcedony, and crystalline quartz (sometimes in the form of amethyst) are prominent in the ancient lava flows of the Watchungs and can be readily seen as embedded nodules along exposed fronts. Datolite, another nodular mineral, has been found embedded in the volcanic rock around the Great Falls. Additionally, jasper and satin spar are known to exist within the northwestern Preakness Range.^[14][15]

Copper can also be found in the Watchungs. Near Belleville, ore containing 8% copper was discovered, and a copper mine once operated in the area. Other copper bearing ores have been noted near Paterson. These ores typically contain cuprite (red copper oxide) and/or copper carbonate in a matrix of red or gray sandstone. Pyritous copper, also known as chalcopyrite, is not known to exist in ores found in the Watchungs.^[14]

Conservation

A traprock glade straddles the summit of First Watchung Mountain

In the mid-twentieth century, the ability of the Watchungs to hold back the spread of urbanization was greatly reduced with the development of the interstate highway system. Two interstate highways, I-80 and I-78, were sliced through the Watchungs, allowing suburbia to invade its inner valleys and slopes. Near the end of the century, I-287, a great semi-circular beltway enclosed the Watchungs within the bulge of suburbia radiating out from New York City.

Today, along the summits of the Watchungs, talus slope environs as well as globally rare traprock glade/outcrop communities and their unique species have become threatened by development. As a response, efforts to conserve the unique landscapes of the Watchungs have been undertaken. The largest of the conservation efforts so far is High Mountain Park Preserve, which at 1153.7 acres sets aside one of the largest tracts of wilderness in the New Jersey Piedmont. The park is known to contain at least one globally imperiled plant, Torrey's mountain mint (Pycnanthemum torrei), as well as three other plants endangered within New Jersey.^[1][16]

General awareness of the history and natural environment of Watchungs has been increased through efforts such as the construction and designation of the Lenape Trail. The trail traverses rugged sections of the mountains while at the same time connecting various historical sites pertinent to the history of New Jersey.^[17]

Recreation

Washington Valley in Bridgewater between the first and second ridge

Parks and reservations from north to south:

• Campgaw Mountain Reservation, Campgaw Mountain (First Watchung Mountain)
• High Mountain Park Preserve, Preakness Range (Second Watchung Mountain)
• Great Falls State Park Under Development, First Watchung Mountain
• Garret Mountain Reservation, First Watchung Mountain
• Mills Reservation, First Watchung Mountain
• Hilltop Reservation, Second Watchung Mountain
• Eagle Rock Reservation, First Watchung Mountain
• Riker Hill Park, Riker Hill (Third Watchung Mountain)
• Lenape Trail, First, Second, & Third Watchung Mountain
• South Mountain Reservation, First & Second Watchung Mountain
• Watchung Reservation, First & Second Watchung Mountain
• Washington Valley Park, First & Second Watchung Mountain

Image Gallery

Cliff face on First Watchung Mountain displaying jointed columns of stacked basalt.

Washington Rock in Green Brook Township, New Jersey.

Geology typical of the Watchung Range.

View of New York City from First Watchung Mountain.

The backside of the Palisades seen from First Watchung Mountain approximately 13 miles away.

See also

• Cushetunk Mountain, an igneous intrusion south of the Watchungs which also formed during the Mesozoic
• Glacial Lake Passaic, a prehistoric proglacial lake held back by the Watchungs
• Metacomet Ridge, a volcanic mountain range in southern New England which formed around the same time as the Watchungs
• Snake Hill, an igneous rock intrusion, probably a volcanic plug, jutting up in the middle of the New Jersey Meadowlands
• Sourland Mountain, a diabase sill and possible continuation of the Watchungs in Hunterdon County
• The Palisades, a nearby volcanic sill that may have formed at the same time as the Watchungs

References

External links

• Geology of the Newark Basin and Connecticut River Basin
• U.S. Geological Survey - South Mountain Reservation
• New York-New Jersey Trail Conference - Watchungs Region

v • d • e Geology of the Newark Basin Extrusive Volcanism Watchung Mountains Campgaw Mountain  • Preakness Range  • Goffle Hill  • Newark Mountains Watchung Outliers Ladentown Basalt  • Union Hill  • New Germantown Basalt & Round Top  • Prospect Hill  • Sand Brook Basalt  • Jacksonwald Basalt Intrusive Volcanism Palisades High Tor  • Hook Mountain  • Clausland Mountan  • Tallman Mountain  • Palisades Sill  • Snake Hill Other Intrusives Cushetunk Mountain  • Sourland Mountain  • Mount Gilboa  • Bowman’s Hill  • Solebury Mountain  • Buckingham Mountain  • Jericho Mountain  • Haycock Mountain  • Millers Point Sedimentary Strata Newark Supergroup Passaic Formation  • Lockatong Formation  • Stockton Formation Other Formations Feltville Formation  • Towaco Formation  • Boonton Formation Faults Ramapo Fault Hopewell Fault  • Flemington Fault Eastern North America Rift Basins