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We'll take an eight mile hike around the Marin headlands (Trip 2 in Geologic Trips SF and Bay Area). Stops include Rodeo Beach (sandstones, near Fort Cronkhite parking lot), Point Bonita Lighthouse (pillow basalts, but it looks like the trail may be closed due to a rockslide), and Battery 129 (red chert and pillow basalts). Half-hour lunch at Hawk Hill. We'll probably get back around 3:30-4:00. You can see an Alltrails map of the hike here.

  • Distance: about 8 miles
  • Time: Probably 5-6 hours (based on previous years, not guaranteed)
  • Elevation gain about 1,000 feet (one 1/2 mile section is quite steep with many stairs)
  • Terrain: About 60-70% roads, 30-40% single track hiking trails.

I have a page on my website with more information about the geology of Marin Headlands (it's still in draft mode, but I hope to have it finished before the hike).

Itinerary (approximate):

  • First 15 minutes is a background talk on Bay Area geology. We'll leave for the beach about 10:45.
  • We'll explore sandstones at the beach, as well as examine the sand grains at the beach.
  • 3 miles (trails and road, lots of uphill) to Battery 129. Lunch here. Lots of great chert beds. It's (almost) all downhill from here!
  • 3 mile hike (mostly road, mostly downhill) to Point Bonita Lighthouse (lighthouse is closed due to landslide this year, but hopefully we can see the pillow basalts).
  • 1.5 miles to get back to start (mostly trail).

I'll have a few hand lenses and weak acid to help us explore the rocks we see. Bring your own hand lens if you have one. Be sure to bring protection from the wind, it often blows strongly even on warm days.

Where to meet: We'll meet at the Fort Cronkhite parking lot at the far end near the bus stop and restrooms.

  • Size limit: I've haven't set a limit, but generally we get 15-30 hikers (after usually 50% no-shows).
  • Carpools: Hikers are encouraged to carpool. If you can offer a ride, or would like a ride, please mention so (and your home city) in your RSVP.
  • Public transit: Unfortunately, MUNI has 'suspended' the bus that used to go from downtown SF to the beach.
  • Kids: Kids who can make the hike are always welcome (this hike is on the longer side!)
  • Dogs: Due to previous bad experiences with dogs, my policy is that dogs are not permitted. (And some of our hikes go to places where dogs are not permitted.)

Previous trip pages:

Events in Sausalito, CA

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