The Palisades Cliffs are the eastern edge of a long, low mountain ridge that rises along the western shore of the Hudson River for more than 40 miles, from Staten Island north to Haverstraw, New York. The 12-mile section of the cliffs contained in the Palisades Interstate Park in New Jersey is roughly in the middle of this long ridgeline.
The name “Palisades” was given to the cliffs because they are formed from vertical columns of rock that resemble a stockade-type fence, or palisade. (A Native American name for these cliffs was Wee-Awk-En : “rocks-that-look-like-trees.”)
Photo: Anthony Taranto.
The highest point along the Palisades ridgeline is at High Tor, 832 feet (254 m) above sea level, in High Tor State Park in Rockland County, New York. In New Jersey, the highest point on the cliffs is Point Lookout at State Line Lookout in Alpine, 520 feet (158.5 m) above sea level.
The type of rock that forms the Palisades is called diabase. It is an igneous (volcanic) rock similar to basalt. Palisades diabase consists mostly of two minerals, light feldspar and dark augite, which give the rock a distinctive “salt-and-pepper” appearance up close.
Photo: Anthony Taranto.
Around 200 million years ago, at the end of the Triassic Period, as the “supercontinent” of Pangaea broke apart, molten diabase rose from deeper in the earth and forced its way, or “intruded,” into layers of sandstones and shales closer to the surface. The molten rock spread laterally between some of these layers of sedimentary rock. As the molten diabase cooled and hardened, it formed a sill of hard rock beneath overlying layers of softer rock. Over the millions of years since, as the softer rock above and around it eroded more quickly than the hard diabase sill, portions of the sill got revealed to daylight, particularly along the sill’s eastern edge — now visible as the face of the Palisades Cliffs, with its distinctive vertical columns.
At some places near river level in the park, the contact zone can be seen. This was where the bottom of the flow of molten diabase — at temperatures over a thousand degrees Fahrenheit — came into contact with the sandstones and shales beneath it, changing them into metamorphic rock. These sections are often purplish in color, and can seem crumbly (“rotten”) compared with the hard diabase above and around them.
Photo: Anthony Taranto.
The glaciers of the Ice Ages also helped shape the eastern edge of the sill into the cliffs we see today, scouring away the loose rock around them. (On some of the exposed bedrock on the summit of the ridge, north-south running scratches, or “striations,” can be found, carved by debris pushed by the glaciers. Several large “erratics,” boulders carried from distant locations and deposited by the most recent glacier, can also be found along the summit.) The Hudson River and its ancestral streams likewise helped to carve away remnants of the sandstones and shales that once encased the sill.
Time and the elements continue to leave their mark on the great cliffs. The effects can be seen in the gradual processes of weathering — with pieces of cliff face that crack and flake off — or, sometimes, in an explosive burst of fury as a major rockfall sends thousands of tons of diabase into the forest below.
A huge rockfall in 1938 — still the largest in park history — led to press reports that the face of Adolf Hitler could be seen in the Palisades! In an eerie twist, just months after Hitler and his armies were defeated in 1945, a second rockfall erased the unwelcome visage from the cliffs forever…
Photo: Yonkers Ferry Corp. | PIPC archives. News clipping from the Northern Valley Tribune (Tenafly, New Jersey).
The rockfall visible in the photograph above occurred at State Line Lookout at 7:28 PM on Saturday, May 12, 2012 — as recorded by seismographs at Lamont-Doherty Earth Observatory in Palisades, New York. As can be seen in the printout below, the shock waves from the falling diabase lasted about 30 seconds.
Photo: Anthony Taranto. Seismograph printout of May 12, 2012, rockfall at State Line Lookout courtesy of Lamont-Doherty Earth Observatory.
The piles of boulders and debris left at the base of the cliffs by rockfalls are known collectively as talus. Almost all of the talus now piled beneath the Palisades has fallen from the cliff face since the retreat of the most recent glacier, around twelve thousand years ago (most of the talus from before then would have been pushed south by the leading edge of that glacier). Over the millennia, rich soils have collected in the slope formed by the talus, and forests have taken root here beneath the ancient yet ever-changing cliff face.
Hiking across the talus along the “Giant Stairs” section of the Shore Trail.
Photo: Anthony Taranto.
Humans have also had a hand in shaping the Palisades. In the nineteenth century, quarries began mining the talus slope for dock-building material and paving stones. (The quarrymen called the Palisades diabase “trap rock,” from the Swedish Trappa, for “stairway,” because of how it tends to cleave at right angles.) In the 1890s, much larger stone quarries, like Carpenter Brothers’ in Fort Lee, began using dynamite to blast the ancient diabase columns — in effect, creating their own talus — to make crushed stone for roadbeds and for producing concrete.
Carpenter Brothers’ Quarry in Fort Lee.
Photo Courtesy of the Lamb family | PIPC archives.
The New Jersey State Federation of Women’s Clubs led the fight to stop the “vandalism” of the quarrymen and to preserve the tall cliffs. In 1900 the states of New York and New Jersey formed the Palisades Interstate Park Commission for this purpose.
In 1983 “The Palisades of the Hudson” was designated a National Natural Landmark, as “the best example of a thick diabase sill formation known in the United States. Columnar jointing, an olivine zone and thermal metamorphic effects are attributes found in rare combination at this site. The glaciated crest provides impressive evidence of the Pleistocene glacier.”
Though only half a mile wide at its widest, the dramatic topography of the Palisades Interstate Park in New Jersey provides for varied natural habitats along its 12-mile length, including riverfront, talus slope, and summit.
Marsh grasses grow beside a mature hardwood forest along the Palisades riverfront.
Photo: Anthony Taranto.
The Hudson River is an estuary — a branch of the Atlantic Ocean, subject to the ocean’s tidal rhythms — from New York Harbor about 150 miles north to Troy, New York. (The Palisades Interstate Park in New Jersey is in the lower portion of that distance.) During the flood tide — as the ocean current pushes up the river — the river flows north for about six hours. Then, during the ebb tide — as the ocean water recedes and the tide “goes out” — the current runs south for about six hours. Along the park’s waterfront, the river level changes between three and four feet during this cycle. These regular changes in the direction of the river’s flow stir the Hudson’s naturally muddy riverbed. This makes the water cloudy and gives the river its distinctive brownish-green appearance.
These photos were taken at Ross Dock Picnic Area on the same day. On the left is high tide. On the right, just six hours later, is low tide.
Photos: Anthony Taranto.
Ross Dock Picnic Area .
The river water here is brackish — part salt, part fresh — as incoming seawater mixes with the fresh water flow that originates over 300 miles north in the Adirondack Mountains. This creates a rich habitat for a diversity of marine life, with a mix of fresh and salt water species living in the same area. Common species caught by visitors fishing along the riverfront in the park include catfish, striped bass, white perch, tomcod, eels, and blue-claw crabs.
Fishing birds, such as herons and kingfishers, as well as bald eagles and osprey (pictured), can be seen along the waterfront.
Photo: Liam Keegan.
As it erodes, the diabase of the cliffs and talus slopes of the Palisades forms a rich soil, and dense plant growth thrives in the sunny spaces along the riverfront. Grape vine, poison ivy, wineberry, and honeysuckle are among the plants commonly encountered by hikers on the Shore Trail.
Hiking in the Forest View meadow, along the riverfront.
Photo: Anthony Taranto.
Mature forests grow on the talus slope between the shore and the cliff faces — sometimes just yards from the jungle-like growth along the riverfront. Oak-maple is the dominant forest type, with sweet gum and tulip trees also prevalent.
Hikers explore the mature oak-maple forest of the Palisades talus slope.
Photo: Lindsey Stabile.
The summit of the Palisades can be a harsh environment. In many places the soil is only several inches deep, and hikers on the Long Path cross large sections of exposed bedrock. Still, like the riverfront below, the open sunlight along the cliff edges allows vine communities to thrive (including robust stands of poison ivy). Exposed to strong winds on the summit, trees that achieve tall heights are subject to being uprooted in storms — opening still more sunlit spaces for vines and bushes to grow.
Winter on the summit of the Palisades.
Photo: Ken Habermann.
Because the soil on the summit of the Palisades is too thinly spread to hold much water after a rainfall, streams typically fill or even overflow during and immediately after storms, producing dramatic cascades down the mountainside for several hours up to a day or two. The flow soon subsides to a trickle, however, and in dry weather these same streams all but vanish into their beds. In other places along the summit, however, the underlying diabase can trap rainwater in shallow pools, called vernal ponds, which can be their own rich micro-habitats, supporting animals such as salamanders and frogs.
Vernal pond on the Palisades summit.
Photo: Ken Habermann.
Where streams have carved ravines through the diabase from summit to talus slope, hemlock trees were until recent times prominent, but have mostly been killed by the wooly adelgid, an invasive insect infestation — which has brought about the loss of this unique and productive Palisades habitat. This points to an ongoing issue, not just in this park but around the globe, as non-native, or invasive, species are introduced to long-existing habitats. The invasive species often disrupt and endanger those habitats. Among the invasive species that are commonly encountered by visitors in the park are relatively benign ones, such as the paulownia tree, to much more aggressive plant species, including ailanthus, Japanese knotweed, and Virginia creeper and “mile-a-minute” vines.
Green Brook after 2+ inches of rainfall.
Photo: Ken Habermann.
Some plants that bloom on the Palisades…
Turtlehead (Chelone glabra ).
White Snakeroot (Eupatorium rugosum ).
New England Aster (Symphyotrichum novae-angliae ) .
Common milkweed (Asclepias syriaca ).
Black-eyed Susan (Rudbeckia hirta ).
Common mullein (Verbascum thapsus ).
Pasture rose (Rosa carolina ).
Silky dogwood (Cornus amomum ).
Smooth small foxglove (Aureolaria flava ).
Sweet pepperbush (Clethra alnifolia ).
Pink lady’s slipper (Cypripedium acaule ).
Tulip tree (Liriodendron tulipifera ).
Yellow star grass (Hypoxis hirsuta ).
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Most of the wildlife in the park is the same that can be found in wooded areas — even in backyards — in the adjoining and nearby suburban communities of Bergen and Rockland Counties.
DO NOT FEED WILDLIFE IN THE PARK
However well intended, it does more harm than good!
In spring and summer, it is common to encounter what may appear to be sick, injured, or orphaned young animals in the park. Most often, these animals are healthy — and safe where they are!
DO NOT DISTURB THEM
Please click here to learn more.
Among the mammals most commonly seen by park visitors (or whose signs and tracks are most commonly encountered) are gray squirrels, eastern chipmunks , raccoons, possums, skunks, red and gray foxes, and red bats. Over the past generation, white-tailed deer have also become commonplace, and eastern coyotes have returned to the woods here. (Occasionally, a black bear is reported in the park, typically a young male bear exploring for territory, but these animals do not live in the park. Click here for information about black bears and what to do if you encounter one.)
Red fox kit in the woods in Alpine.
Photo: Emil Fiore.
Among the reptiles and amphibians seen by visitors in the park are the five-lined skink — New Jersey’s only lizzard — as well as black rat snakes, garter snakes, and, less commonly, milk snakes, ring-neck snakes, northern watersnakes, and copperhead snakes. The copperhead is the only venomous snake found in the park, though unless attacked or harrassed, it poses little threat to humans or our pets. (Click here to read more about the snakes found in the park.) Frogs and salamanders can be found near marshy areas, and turtles, including large snapping turtles, are sometimes seen as well. All of these animals are protected by law.
Between the river and the forest heights, a great diversity of birds can be seen throughout the park, from year-round residents, to those that arrive seasonally to nest, to spring and autumn migrants. Among the year-round residents, red-tailed hawks and turkey and black vultures are among the most memorable, seen as they soar above the cliffs, effortlessly climbing the thermal updrafts created as the sun warms the ancient diabase columns.
A mother eagle feeds her offspring under the Palisades.
Photos: Liam Keegan.
