The Marin Headlands is a hilly peninsula at the southernmost end of Marin County, California, United States, located just north of San Francisco across the Golden Gate Bridge, which connects the two counties and peninsulas. The Marin Headlands were home to the Native American Coastal Miwok tribe, who moved between the bay side of the peninsula and the ocean side seasonally, for thousands of years. The entire area is part of the Golden Gate National Recreation Area. The Headlands are famous for their views of the Bay Area, especially of the Golden Gate Bridge. In the waters surrounding the Headlands, harbor seals can be found year-round, gray whales can be seen in the spring and fall, and seabirds such as common murres and surf scoters swim within sight of shore.
Sunset on Rodeo Beach, located in the Fort Cronkhite area of the Marin Headlands, one of the most special places in the Golden Gate National Recreation Area with access to multiple trails, fantastic views, a dog-friendly beach, fascinating geology, and an interesting history. As a pocket beach, Rodeo Beach sands do not migrate up or down the coast. Instead, they are carried a short distance offshore in winter, tumble about in the surf, and then return to replenish the beach in the spring and summer. Thus, the sands of Rodeo Beach are native to the Marin Headlands and reflect the Franciscan geology of the closest hills and cliffs. This earthcache focuses on the abundant radiolarian chert and rare carnelian pebbles.