Pennsylvania Highlands Geology

The Pennsylvania Highlands are the foothills of the Appalachian Mountains. The irregular ridges and deep valleys of this unique landscape feature common themes that reflect the region’s geology, which has influenced local history and land use. Much of the Pennsylvania Highlands are comprised of the Reading Prong Geologic Formation. The Reading Prong is found primarily in Berks, Bucks, Montgomery, and Northampton Counties.

Two types of rock are common to the erosion resistant, largely forested ridges of the Pennsylvania Highlands: diabase (basalt), and granitic gneiss and quartzite (see map). The diabase areas create natural limitations for agriculture and land development, due to the size and abundance of boulders. As a result, these areas feature large contiguous woodlands such as Hopewell Big Woods and Unami Hills.

The high iron content in the gneiss and quartzite rock ridges provided the raw material for the region’s industrial legacy of iron and steel. This legacy is reflected in the names of towns, historic sites and parks found throughout all thirteen counties of the Pennsylvania Highlands region: places such as Durham Furnace, Coventry Forge, Hopewell Furnace, Johanna Furnace, Cornwall Furnace, and Pine Forge Furnace. The desire for a recreation resource to connect these historic areas and unique natural resources was the impetus for development of the Highlands Trail in Pennsylvania. The unique combination of forests, rocky hills, historic sites, industrial towns, and fertile limestone valleys makes for a compelling story told through interpretive signage and online tools, enhancing the experience of trail users.

Diabase boulders along the Unami Creek, Montgomery County

News

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Highlands Organizations submit letter requesting FY21 Federal Funding

Organizations in the four-state Highlands region, the PA Highlands Coalition, Appalachian Mountain Club, and partners worked together to submit FY21 federal appropriations requests on behalf of the federal Highlands program, a program of the Land and Water Conservation Fund. Read More

PA Highlands Coalition to host Webinar on Kittatinny Ridge, Global Important Bird Area

On Monday, April 6th, 2020 at 1:00pm, esteemed panelists will join the PA Highlands Coalition to host the webinar “Protection of the Kittatinny Ridge: A Global Important Bird Area.” Read More

AMC Advocates for the Delaware River Watershed in Washington DC

On Tuesday, March 10th, 2020 Appalachian Mountain Club joined advocates from the Coalition for the Delaware River Watershed (CDRW) for the Coalition’s annual Hill Day event. Read More

Construction Begins on Upper Bucks Rail Trail

The Upper Bucks Rail Trail is now in the construction phase. The project, located in Springfield and Richland Townships, will cover three miles of unused railbed from Veterans Park in Richland to just outside Coopersburg, in Springfield Township. Read More