Located in Wilmington, DE, the Cliffs of Alapocas Woods are opposite the old Bancroft Mills across the Brandywine Creek. Along the creek you will find large exposures of Brandywine Blue Gneiss. Compared to other outcrops in the Piedmont of Delaware, the rock examples here are massive. When observed closely, the felsic gneiss displays a medium grain size. Most of early Wilmington was built from the stone from these quarries. These impressive rock features are enjoyed by local rock climbers as well as many who use the Northern Delaware Greenway.
Alapocas Woods Park
This report accompanies a new map that revises the original bedrock geologic maps of the Delaware Piedmont compiled by Woodruff and Thompson and published by the Delaware Geological Survey (DGS) in 1972 and 1975. Combined detailed mapping, petrography, geochemistry, and U-Pb geochronology have allowed us to redefine two rock units and formally recognize eleven new units. A section of the Pennsylvania Piedmont is included on the new map to show the entire extent of the Mill Creek Nappe and the Arden Plutonic Supersuite.