The Point Reyes Peninsula has long baffled geologists. Why should the rocks of this craggy coast match rocks in the Tehachapi Mountains more than 310 miles to the south? The answer lies in plate tectonics and the continual motion of the Earth’s crust.
Geologically, Point Reyes National Seashore is a park on the move. The eastern border of the park parallels the San Andreas Fault, which is the current tectonic plate boundary separating the Pacific Plate from the North American Plate.
The remaining sides of the peninsula are intermittently edged by beaches, sea cliffs, and intertidal zones cascading into the Pacific Ocean. Encircled by this rich assemblage is a mosaic of ecosystems arranged by factors such as geologic foundation, climate, and exposure. While there are dozens of ways to classify and name the exact type of ecosystem, the broadest and closest category places Point Reyes National Seashore into a Mediterranean Ecosystem.National Parks Service