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Delaware Canal State Park

Natural Areas

Pennsylvania state park natural areas are of unique scenic, geological or ecological value. These areas are maintained in a natural condition by allowing physical and biological processes to operate, usually without human intervention. Natural areas are set aside to provide locations for scientific observation of natural systems, to protect examples of typical and unique plant and animal communities and to protect outstanding examples of natural interest and beauty.

Delaware Canal State Park has two designated state park natural areas – Nockamixon Cliffs and River Islands. These areas contain threatened or endangered species and are unique natural environments. Visitors are welcome to explore these areas, but are asked to abide by the old saying, “take only pictures, leave only footprints.” Camping within natural area, including the river islands, is prohibited.

River Islands

Eleven state park river islands are now protected natural areas within a river corridor that is experiencing dramatic economic growth. The islands provide critical habitat for migratory waterfowl and songbirds, contain sites of archaeological importance, and enhance recreational opportunities for fishermen and canoeists.

Some river islands, such as Hendrick Island, were originally park of the main shoreline, but most islands grew individually from the river itself. Silt and stone left by glacial waters almost 10,000 years ago form the substrate of these islands. Seeds were eventually deposited by wind, water or wildlife. As plants grow on the islands, the roots bind the substrate materials together. Although they are relatively stable, the size, shape and location of the islands shift slightly with the movement of the river water.

Nockamixon Cliffs

Topography, geology, and scenic beauty combine to create the unique character of the Nockamixon Cliffs Natural Area. These sheer cliffs tower 300 feet above the Delaware River and dominate the landscape. Because the cliffs face the north, they receive little direct sunlight. This cool habitat supports an alpine-arctic plant community unusual this far south. Almost directly across the Delaware River, an opposite set of circumstances occurs, creating habitat for unusually arid plants.

Nockamixon Cliffs originated geologically from reddish sands and mud carried by torrential streams from the northwest. Massive amounts of these sediments were deposited into temporary shallow lakes. The resulting red sandstone and shale can still be found throughout the region. They are bright red and break easily into flakes and fragments.

Toward the end of the Triassic Period, molten magma from deep with the earth’s crust flowed into these beds of sedimentary rock. The “igneous intrusions” heated the surrounding sandstone and shale, changing them into tough, weather-resistant rock called hornfel.

During the Jurassic Period, the region was subjected to continuous erosion. While some other rock, such as the sandstone and shale were worn away, the hornfel resisted weathering, allowing the Nockamixon Cliffs to “rise” above the surround landscape.

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