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| Watchung Mountains | |
|---|---|
| Wach Unks;(formerly) Blue Mountains; Blue Hills | |
 Garret Mountain and Mount Cecchino seen from High Mountain inWayne, New Jersey | |
| Highest point | |
| Peak | High Mountain (Preakness Range) |
| Elevation | 879 ft (268 m) |
| Coordinates | 40°58′12.26″N74°11′54.08″W / 40.9700722°N 74.1983556°W /40.9700722; -74.1983556 |
| Dimensions | |
| Length | 40 mi (64 km) north–south |
| Geography | |
 | |
| Country | United States of America |
| State | New Jersey |
| Geology | |
| Rock ages | |
| Rock types | |
TheWatchung Mountains are a group of three long lowridges ofvolcanic origin, between 400 and 500 feet (120 and 150 m) high, lying parallel to each other in northernNew Jersey in theUnited States. The name is derived from the American NativeLenape name for them,Wach Unks (High Hills). In the 18th century, the Euro-American settlers also called them theBlue Mountains[Notes 1] orBlue Hills[Notes 2] (not to be confused withBlue Mountain in Sussex County). The Watchung Mountains are known for their numerous scenic vistas overlooking the skylines of New York City andNewark, New Jersey, as well as their isolated ecosystems containing rare plants, endangered wildlife, rich minerals, and globally imperiledtrap rock glade communities.[1][2] The ridges traditionally contained the westward spread of urbanization, forming a significant geologic barrier beyond the piedmont west of the Hudson River; the city of Newark, for example, once included lands from the Hudson to the base of the mountains. Later treaties moved the boundary to the top of the mountain, to include the springs.
The Watchungs are basalt uplifts, geologically similar tothe Palisades along the Hudson River. In many places, however, the mountains have become sinuous islands of natural landscape within the suburban sprawl covering much of contemporary northeastern New Jersey. Parks, preserves, and numerous historical sites dot the valleys and slopes of the mountains, providing recreational and cultural activities to one of the most densely populated regions of the nation.
The two most prominent ridges, known asFirst Watchung Mountain (the southeastern ridge) andSecond Watchung Mountain (the northwestern ridge), stretch for more than forty miles (64 km) fromSomerville (inSomerset County) in the southwest throughMorris County,Union County,Essex County, andPassaic County toMahwah (inBergen County) in the northeast. Sometimes the less prominent and discontinuous ridge formed byLong Hill,Riker Hill,Hook Mountain, andPackanack Mountain is referred to asThird Watchung Mountain and lies on the northwestern side of Second Watchung Mountain. A parallel series of gaps through all three mountain ridges extends to the west from nearSpringfield to the northern boundary ofChatham where the Passic River flows through the Third Watchung Mountain.[citation needed]
Often the entireties of First Watchung Mountain and Second Watchung Mountain are erroneously referred to asOrange Mountain andPreakness Mountain. Historically, the names ‘Orange’ and ‘Preakness’ have only been applied to specific sections of these ridges.[3][4] The confusion appears to have arisen from the fact that First Watchung Mountain is said to be composed of Orange Mountainbasalt, while Second Watchung Mountain is composed of Preakness Mountain basalt. The names applied to the basalts are geologictype localities,[5] that is to say, the type of rock found at Orange Mountain is exclusive to all of First Watchung Mountain, while the type of rock found at Preakness Mountain is exclusive to all of Second Watchung Mountain. Similarly to this misinformation about First Watchung Mountain and Second Watchung Mountain, sometimes the Third Watchung Mountain is confused with its basalt type locality, as on some occasions its entire length is erroneously referred to asHook Mountain.[citation needed]
In addition to the three main ridges of the Watchungs, a smaller fourth ridge exists south ofMorristown and west of Third Watchung Mountain.[6] While attaining elevations more than 400 ft (120 m) above sea level, the ridge lacks topographic prominence, only rising to approximately 100 ft (30 m) above the surrounding terrain. Only one portion of the ridge is named, a southern section underlyingHarding Township known asLees Hill.[citation needed]
All of the ridges lie to the east of the higherAppalachian Mountains, which in northern New Jersey often are referred to as theNew York - New Jersey Highlands. Together with the Appalachian Mountains to the west, the Watchungs pen in an area formerly occupied by the prehistoricGlacial Lake Passaic. The Great Swamp, a large portion of which is designated as theGreat Swamp National Wildlife Refuge, is a remnant of this glacial lake and presently is retained by Third Watchung Mountain.[citation needed]
Although the Watchungs commonly are described in terms of their east-west ridge arrangement (First Watchung Mountain, Second Watchung Mountain, and Third Watchung Mountain), they also are divided into smaller mountain ranges, as well as various named ridges.[citation needed]
Notable ranges and ridges of the Watchungs from north to south include:
Noteworthy summits of the Watchungs includeHigh Mountain,Beech Mountain, andMount Cecchino inWayne, which stand at 879 ft (268m), 869 ft (265m) and 755 ft (230m) above sea level. Another notable summit isThe Hilltop inVerona,Cedar Grove, andNorth Caldwell, which peaks at 675 feet (206 m) just east of the water sphere.[citation needed]
The Watchung Mountains formed millions of years ago when the continent ofAfrica collided with North America.[8] The original inhabitants of the Watchungs, theLenape, referred to the mountains as theWach Unks, or ‘high hills’.[9][10] Evidence of the Lenape presence in the Watchungs can be seen in 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 that 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.[11] They took advantage of the rich soils and maintained many farm areas where they raised a variety of seasonal crops. The Lenape Trail goes along the edge of the cliffs of the Watchung Mountains and the Lenape used the overlooks there as smoke signal locations.[citation needed]
With the arrival of Europeans, the same resources that sustained the indigenous peoples served settlers. Trade in furs to European markets, a bounty of game and fish, and native garden produce for the traders was important during the Dutch colonial period when few settlements occurred. Perhaps most importantly with the settlements established during the English colonial period, the rivers and streams of the Watchungs also supported grain, grist, and saw mills.[12] Later, the energy of these rivers would be harnessed for industry, most notably at theGreat Falls of the Passaic River, where mechanical and hydroelectric systems exploited the energy of water falling over the face ofFirst Watchung Mountain.[13]
Outside of providing gradation to rivers and streams, the height of the Watchungs has proven useful for other reasons. In theFrench and Indian War, the military reused the Lenape signal points, as did Washington later.
200 million years ago, magmaintruded into theNewark Basin, then an active rift basin associated with the breakup of the supercontinentPangaea.[16] Initially, the magma was contained within the sedimentary strata of the basin, forming large intrusions such as thePalisades Sill, but it ultimately broke out to the surface through large, episodic eruptions.[17] The Watchung Mountains were formed from these eruptions, consisting of three separateflood basalts that may have filled nearly the entire Newark Basin.[5] Each time the basin filled withbasalt, which cooled into blockytrap rock, a period of limited volcanic activity followed, allowing sediment to be deposited on top of the previously erupted layer of basalt. In this way, the Newark Basin became layered with alternating strata of Watchung basalt and Jurassic sedimentary rock.[5]
Throughout the early Jurassic, the Newark Basin underwent extensive dipping and folding. The western side of the basin plunged deeper into the crust, tilting the strata of the basin to an angle of between 5 and 25 degrees.[5] Localized deformation of the western edge of the basin along theRamapo Fault System formed alternatingsynclines andanticlines that warped the layers of basalt and sedimentary rock.[18]
Erosion began to attack the basin as rifting failed and deposition of new sediments ceased. Over millions of years, erosion ate downward through the tilted rock of the basin, eventually encountering the basalt layers that are significantly more erosion resistant than the surrounding sedimentary rock. The result of this has been that the exposed edges of the eroding basalt layers have managed to persist longer than the exposed edges of the sedimentary layers, causing them to project prominently above the surrounding surface terrain as high ridges.[16][19]
Today, the flood basalts are preserved in the synclines adjacent to the Ramapo Fault system.[5] It is in these synclines that the basalt layers are thick and warped into downward dipping trap rock sheets, descending below the current erosional surface of the basin. Notably, the synclines preserve not only the basalt layers, but also some overlying Jurassic sedimentary rock. The largest syncline in the basin, the Watchung syncline, contains the greater portion of the Watchung flood basalts as they appear today. The projecting, eroding edges of the flood basalts preserved in the syncline form the three ridges of the Watchung Mountains.[16] Jurassic sedimentary rock layers between and above the three ridges form theFeltville,Towaco, andBoonton formations. Elsewhere in the Newark Basin, smaller synclines preserve theWatchung Outliers, additional fragments of the flood basalts and associated overlying sediments that have survived into the modern era.[5] The Hook Mountain and Preakness layers have undergone hydrothermal alteration causingalbitization.[20]
Because the majority of the Watchung Mountains are composed ofextrusiveigneous trap rock, they display characteristic columnar jointing and stacked lava flows. These features are readily noted along the eastern faces of the ridges that often present mural precipices, or verticalescarpments. Similar features also can be seen in thePalisades Sill, although these were formed within the Earth's crust.[9] Additionally, the Watchungs feature not only blockyaa lava, but also ropey and billowingpahoehoe flows.[9]
The magma that generated the Watchungs and the Palisades also formed the intrusive igneousSourland Mountain in Central New Jersey, as well as a series of smaller outlying volcanic ridges in the region.Cushetunk Mountain, a ring-shaped volcanic mountain between Sourland Mountain and the Watchungs, is of the same geologic lineage.[citation needed]
TheMetacomet Mountains in the Connecticut River Basin, another aborted rift valley, came into existence at approximately the same time as the Watchungs, also through extrusive eruptions. While non-contiguous, the two ranges may be considered geologic cousins, having formed under similar circumstances during the rifting of Pangaea. The same erosive and tectonic forces that elevated the Watchungs, also served to raise the Metacomets.[16]
The Watchungs are composed principally of volcanicbasalt, which historically has been used in railroad beds and road construction. In addition to this, in many places the mountains are underlain by red and white sandstone that, at times, has been used in building construction. Mica and calcareous spar often accompany these sandstone beds.[citation needed]
Due to the volcanic nature of the Watchungs,zeolites, includingprehnite,analcime, andstilbite, which form from a reaction of mafic rocks in alkaline environments, can be found along exposed ridge lines.Agate, primarily in the form ofchalcedony, and crystalline quartz (sometimes in the form ofamethyst), are prominent in the ancient lava flows of the Watchungs and typically, are seen as embedded nodules along exposed fronts.Datolite, another nodular mineral, has been found embedded in the volcanic rock around theGreat Falls. Additionally,jasper andsatin spar are known to exist within the northwestern Preakness Range.[21][22]
Copper also can be found in the Watchungs. NearBelleville, ore containing 8% copper was discovered, and acopper mine once operated in the area. Other copper bearing ores have been noted nearPaterson. These ores typically containcuprite (red copper oxide) and/orcopper carbonate in a matrix of red or gray sandstone. Pyritous copper, also known aschalcopyrite, is not known to exist in ores found in the Watchungs.[21]
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. Three interstate highways,I-80,I-280, andI-78, were built through the Watchungs, allowing midcentury suburban-style development to become economically feasible within its inner valleys and slopes. Near the end of the twentieth century,I-287, a semi-circularbeltway enclosed the Watchungs within the bulge of suburbia radiating out from New York City. Many pathways of safe passage through the mountains, retained from the time of the Lenapes, were severed and blocked by the highways.[citation needed]
Today, along the summits of the Watchungs, talus slope environs as well as globally rare trap rock 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 isHigh Mountain Park Preserve, which at 1,153.7 acres (4.669 km2) 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'smountain mint (Pycnanthemum torrei), as well as three other plants endangered within New Jersey.[1][23]
Other large areas of preserved land lie within the valleys of the Watchungs. Retained within the embrace of Third Watchung Mountain, theGreat Swamp National Wildlife Refuge consists of 7,600 acres (31 km2) or approximately 12 square miles (30.4 km²) of variedhabitats. The refuge was created through the efforts and donations of a small group of local residents in 1959, theJersey Jetport Site Association, and aGreat Swamp Committee later formed within theNorth American Wildlife Foundation. It is championed by many organizations among the contemporary communities adjacent to the refuge. The Great Swamp, as well as other swamps retained by the Watchungs, includingGreat Piece Meadows, constitute the remains ofGlacial Lake Passaic. The lake existed during the last ice age, eventually draining as a glacier in the northern Watchungs receded and allowed the lake's water to empty out via a gap in the ridges of First Watchung Mountain and Second Watchung Mountain currently occupied by the Passaic River.[citation needed]
General awareness of the history and natural environment of Watchungs has been increased through efforts such as the construction and designation of theLenape 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.[24]
Parks and reservations from north to south:
the Watchung Mountains then called the Blue Hills of New Jersey.
