The Wissahickon Creek in northwest Philadelphia is a beautiful natural laboratory for exploring geologic processes including metamorphism, plate tectonics, and surficial geology.  This field guide is intended for the casual geologist, one with an interest rocks and earth history but without formal training.  I hope that you will be able to use it to increase your enjoyment of the park.  Please feel free to contact me ( jea4@psu.edu ) with comments and questions.

    The guide is divided in two sections.  First is a tour of the area between Valley Green Inn and Rex Ave.  The second tours the area along forbidden drive near Bell's Mill Rd.  Valley Green can be approached from either Chestnut Hill (via Springfield Ave.) or Andora (by Wise's Mill Rd.).  Once you reach the Inn, go across the creek and follow the trail along the Wissahickon to the north.  You can return either by retracing your steps or following Forbidden Drive back to the Inn.  Expect the walk with stops to take between 1 and 2 hours.