San Andreas Fault Highlights The San Andreas Fault and fossils on a forgotten beach Distance 3.5 miles one-way Total Elevation Gain/Loss 50'/50' Hiking Time 2-3 hours Recommended Map USGS 7.5-min San Francisco South Best Times September-May Agency Golden Gate National Recreation Area Difficulty * After covering 500 miles overland, the San Andreas Fault dives northwest from the bluffs of Daly City into the Pacific Ocean. North of this tectonic landmark, a beach of surprising seclusion runs for more than 3 miles below cliffs of mud, sand, and fossils. Approximately 2 million years ago, the geography of the Bay Area differed radically. The Point Reyes Peninsula sat directly west of today's Golden Gate, partially enclosing a shallow basin between itself and the mainland. Sediments poured in from the surrounding landmasses, filling the basin with thick layers of sand, mud, and gravel. In all, a deep reservoir of sediment more than a mile thick was deposited. Layers formed during periods of shallow water include thick beds of fossils--crushed shells make up the bulk of the material, but entire preserved sand dollars and clams can also be found. Within the past 300,000 years, changing geometry along the San Andreas Fault lifted the entire basin and tilted its beds gently north to expose it as today's Merced Formation. A small piece of the northern basin remained attached to the southeast corner of the Point Reyes Peninsula as it was wrenched into its current position; it is now exposed in the bluffs east of Bolinas, as explained by Ted Konigsmark in Geologic Trips. The Hike follows the beach north from Mussel Rock in north Pacifica to Fort Funston in San Francisco. This trip can become dangerous during high tides, when big waves can wash to the base of the bluffs and suck people out to sea. Do not venture onto the beach if you see waves reaching the bluffs. No tide tables are posted at the trailhead--check in advance. The hike can be made into a round-trip by returning along the beach to the trailhead. Otherwise, car arrangements must be worked out for the return to Pacifica. For those unable to do the full hike, the general flavor and experience of the locale can be had in a short 1-mile round- trip from the trailhead. While the hike can be done year-round, fog is thick in the summer and makes for a cold, low-visibility day at the beach. Crowds are light compared to other area beaches. No water is available at the trailhead. To Reach the Trailhead From San Francisco, follow Hwy. 1 south, take the first Pacifica exit at Manor Dr., and turn right on Palmetto Dr. Go 0.8 mile and turn left on Westline Dr. Bear left toward the Mussel Rock Transfer Station (the dump), keep left again as the road forks right to the dump, and park in the large lot at the road's end. To reach Fort Funston, take Skyline Dr. (Hwy. 35) 4 miles north from Hwy. 1 in north Pacifica--the parking lot is on the left. Approaching Fort Funston from San Francisco, follow Skyline Dr. 0.8 mile south of the Great Hwy. Description From the parking lot by Mussel Rock, walk through the opening in the fence and descend along roads leading down toward the beach. Looking above you to the west, notice the loose, unconsolidated slopes along the bluffs--the result of many landslides. The bluffs above the landslide area recede at a rate of up to 3 feet per year, undercutting houses that should never have been built or purchased in the first place. The edges of the landslide mark the rough boundaries of the San Andreas Fault Zone, an area approximately a half mile wide. The loose slopes mask any actual fault trace in the hillside, but it is definitely there--the great 1906 San Francisco earthquake had its epicenter immediately inland from this location. Walking north on the beach, notice the northward tilt of the layers in the bluffs. Deposited sequentially, these layers represent a chronology of the former basin environment; they become progressively younger as you go north. Fossil beds can be identified by the white, linear exposures of crushed shells contained in a matrix of mudstone. The views north include most of the Marin coast, and Point Bonita (Hike 28) can be picked out across the Golden Gate on clear days. Fort Funston can be identified near the northern end of the bluffs as they drop in elevation. Turning south, Montara Mountain (Hike 23) forms the skyline closest to the sea, plunging into the ocean at landmark Pedro Point. Continuing north, you pass the deep gash that Woods Gulch makes in the bluffs. Because saturated slopes increase the risk of landslides and accelerate erosion, draining this threatened area is an attempt to slow the imminent destruction of its cliffside homes. The number of people increases as you approach the path that leads up to the viewing platform and parking lot at Fort Funston. A former military reservation developed at the turn of the century, Fort Funston is now part of the Golden Gate National Recreation Area. It's a popular site for hang gliders and parasailors between March and October, when strong west winds rise over the bluffop. Nearest Visitor Center The Pacifica Chamber of Commerce runs an excellent visitor center in partnership with the Golden Gate National Recreation Area. Near the south end of Pacifica at 225 Rockaway Beach, it's open Monday-Friday 10 a.m.-5 p.m. year-round, and 11 a.m.- 3 p.m. on weekends in summer. For information call 650-355-4122. Nearest Campground Francis Beach Campground, 650-726-8819, is open year-round at the south end of Half Moon Bay State Beach, just west of Hwy. 1 on Kelly Ave.; the turnoff is 0.3 mile south of Hwy. 92 (52 sites, $35-$50 depending on site). Reservations are essential in summer and for weekends year-round; visit reserveamerica.com or call 800-444-7275. Excerpted from 101 Hikes in Northern California: Exploring Mountains, Valley, and Seashore by Matt Heid All rights reserved by the original copyright owners. Excerpts are provided for display purposes only and may not be reproduced, reprinted or distributed without the written permission of the publisher.
