Reports
Welcome to Gambrill State Park, geologic features
2011, Maryland Geological Survey
Poster 2011-01
Abstract
Did you know…
- The rocks exposed in Gambrill State Park are about 550 million years old.
- The Middletown Valley was once a mountain underlain by rocks over a billion years old (see Middletown Valley overlook diagram below)
- High Knob exists because the hard sandstone of the Weverton Formation (stop 1) is much more difficult to erode than the underlying Loudon and Catoctin Formations
- The greenish rocks along Route 40 between Gambrill Park Road and Ridge Road were originally lava flows (Catoctin Formation).
