The Wissahickon Gorge - Philadelphia, PA
Posted by: Groundspeak Regular Member Math Teacher
N 40° 04.313 W 075° 13.537
18T E 480761 N 4435759
One of the most beautiful, natural places highlighted w/ vernacular structures can be found inside of all places, the city limits of Philadelphia. Cascading waters, WPA structures, & geologic formations & unlimited rocks make this a place a must see.
Waymark Code: WMHVFY
Location: Pennsylvania, United States
Date Posted: 08/15/2013
Published By:Groundspeak Premium Member Neos2
Views: 10

Inside the western city limits of Philadelphia is a natural retreat hidden in a rugged gorge, with a covered bridge, an old inn, and a statue that commemorates the last Native American chief in the Wissahickon Valley, a really cool, old arched, stone bridge and sights unseen by most people who dare not to venture this far into the wild. The park system has a great mix of paved paths, gravel and dirt for walking/jogging/biking/hiking. It also has a lot of single track for mountain biking (permit needed for certain areas). The trail from Northwestern Drive to the Valley Green Inn and back is a scenic 5 mile loop (that's 2.5 miles each way).

I really love this place despite getting lost several times. The Wissahickon Valley also called the Wissahickon Gorge, offers both challenging hikes and short walks. There's also intermittent access to the huge, fast-running stream, and lots of historic sites scattered in all sorts of hard to reach places. Most impressive were the rocks and rock formation both in the creek, along the myriad trails and high above on the cliffs. The Wissahickon Gorge belongs to the Piedmont Province of Pennsylvania, a strip of sloping land rising from the Atlantic coastal plain on the eastern side of the Appalachian Mountains. The creek drops more than 100 feet in altitude as it passes through the gorge, before it finally merges with the Schuylkill River.

Due to a fault line that runs nearby, the area has shifted significantly over the millennia. The rock we see today was once more than 10 miles below the surface. The tectonic plates lifted and convoluted the strata of rock with pressure and heat so great that the nature of the rock changed from a granite bedrock formation into a waving and blistered schist. It can be seen everywhere along the creek. The good news is that this geologic action created a treasure trove of crystals to be found with a little effort. Mica, garnet, Tourmaline, and kyanite and others minerals are everywhere. So, it is a great place to go with a bucket, strainer, and geo hammer. The garnets are a rich cranberry red, the tourmaline red, brown and green, and the kyanite a rich sky blue. Everything there is to know about rockhounding at this site can be found HERE.

A good place to start your visit is Forbidden Drive, named back in the 1920s because cars were and still are largely banned. Head to Valley Green where you can park your car and stretch next to a rustic inn that serves full meals and snacks, before heading onto Forbidden Drive. From this gravel path you can access trails with more strenuous and steeper terrain for hiking, trail running, mountain biking, and even horseback riding. SOURCE

Official Philadelphia Tourism Narrative
There are 57 miles of trails in this lush, 1,800-acre gorge, crossing forest and meadow before plunging down to the sun-dappled waters of the Wissahickon Creek. You’ll find yourself lost in a feeling of wilderness as you walk, bike or ride your horse through this undisputed gem of Philadelphia’s Fairmount Park system.

Relax along Forbidden Drive, the low-lying gravel road that follows the creek, or venture up the steeply wooded paths for a more challenging hike or off-road cycling adventure. If you’re thirsty, or you need a snack, visit the historic Valley Green Inn, the last remaining example of the many roadhouses and taverns that once flourished here.

The Wissahickon, blessed with a fairly stable resident population of owls, chickadees and titmice; five species of woodpecker; nuthatches; blue jays; Carolina wrens; mourning doves; goldfinches and cardinals, was recently named and “Important Birding Area” by the National Audubon Society.

Despite the feeling of quiet wilderness, you’ll find plenty of history in this lush valley. A series of stone bridges and huts date back to the WPA era; two beloved statues pay tribute to the Leni Lenape tribe of Native Americans and the early Quaker settlers who once loved these grounds; and the now-crumbling dams offer gurgling memories of industrial mills that once drew power from the creek.

The Fairmount Park Commission acquired the 1,800 acres of the Wissahickon Valley in 1868 in order to preserve the purity of the City’s water supply. Mills and taverns were demolished, and in 1920, the wide road paralleling the creek was closed to vehicular traffic and became Forbidden Drive. SOURCE

History
Before European settlers arrived in the late 1600s, the Wissahickon Valley had been undisturbed for thousands of years. Native Americans hunted and fished in the area. They were respectful of nature and did no permanent environmental harm.

When Europeans settled in the valley, they soon began using the Wissahickon's water to power dozens of mills. Logging and quarrying removed trees and stone from the valley and altered the landscape forever. Mills and outhouses polluted the creek and its tributaries. Construction of dams, roads, houses and other structures led to problems with erosion and trash. Non-native plant species were introduced. Many species of animals were hunted and trapped until they were exterminated. By the mid-1800s, the Wissahickon had become an industrial valley, disturbed and polluted by humans.

In the mid-1800s, the City of Philadelphia began to acquire land in the Wissahickon Valley. The Fairmount Park Commission was created in 1867 and restoration of the Wissahickon Valley began shortly thereafter. SOURCE

Fossils: yes

Gems: yes

Minerals: yes

Rock Types:
The predominant bedrock underlying Philadelphia is Wissahickon Schist. First studied and described along the Wissahickon Creek, schist extends in a broad band across southeastern Pennsylvania from Trenton into Delaware and Maryland. In addition to schist, most exposures show layers of quartzite. Wissahickon schist and quartzite are metamorphic rocks formed from sedimentary deposits of mud and sand that at one time were washed off very ancient continents into a shallow sea. These sedimentary deposits were compressed into shale and sandstone. During the long periods of mountain building, the shale and sandstone were slowly transformed into the schist and quartzite we find today. In some places, the compression and heat were extreme enough to fuse the schist with emerging igneous rocks into hard-banded gneiss. Layers of pegmatite are also common in Wissahickon exposures. These are igneous flows that were pushed through deeply buried schist and quartzite during the periods of mountain building. Visitors may also come upon old granite quarries--the remains of granite plutons that moved up into overlying rock layers. Within the schist can be found a variety of mineral crystals, muscovite and biotite micas, garnet staurolite, tourmaline, kyanite, and in some regions, sillimanite. These embedded crystals reveal the conditions of combined temperature and pressure existing in the rocks as they underwent metamorphosis. In a few locations close to Devil's Pool and along Bell's Mill Road, talc schist containing the soft mineral talc that can be scratched with a fingernail is found. This material has risen from very deep within the earth's crust.


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Meteorites: Not Listed

Hours of Operation: Not listed

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