Geology of the Point Reyes Headlands

Explore the Point Reyes headlands on two scenic geology hikes during the same day to the lighthouse and Chimney Rock.

Learn about the unique history of the older granitic rocks and younger sedimentary rocks. The granitic rocks cooled in a magma chamber about 82 million years ago in southern California and have been displaced to the Bay Area on the Pacific Plate by movement on the San Andreas Fault. The Point Reyes Conglomerate at the lighthouse was deposited in a submarine canyon about 50 million years ago and is like the rocks at Point Lobos State Reserve. The Point Reyes Conglomerate has also been displaced by about 110 miles by movement on the San Gregorio Fault System from south of Monterey.

Learn more about this hike (appr. 4 miles).