Marin Headlands: Chert, sandstone, and pillow basalt. Draft: Should be completed by early February 2025. About our hike Rocks we will see in this area include sandstone, radiolarian chert, greenstone, and pillow basalt. This hike is adapted on Ted Konigsmark’s Geological Trips: San Francisco and the Bay Area, Trip 2. We start at Rodeo Beach, … Continue reading “Marin Headlands”