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You’ll feel like a pirate as you descend the steps to the black sand on this hidden beach in the Marin Headlands. Note that the tide can make this a very small black sand beach, so make sure to check tide charts before visiting.
But if the tide looks right, you’re in for a treat. Drive past Hawk Hill on Conzelman Road and park in the Upper Fisherman’s lot. The views of Point Bonita and the Pacific Ocean are unmatched, and the sheltered nature of the south-facing beach makes it feel like you’re on your own piece of coastline.
The sea cliffs and road cuts of the Marin Headlands have exposed some of the finest examples of pillow basalt and radiolarian chert.
Millions of years ago, these rocks formed at the bottom of the sea, several thousand miles from the coast. The black pillow basalt was created from lava spewing from vents, while the red-brown radiolarian chert formed as the remains of radiolarians (microscopic protozoans) collected in layers.
As the seafloor moves slowly east, it slides under the North American continent and leaves behind scrapings of radiolarian chert and pillow basalt.
The lighthouse was originally placed on a hill above the current location and built in 1855. Point Bonita was the third lighthouse to be built on the West Coast after San Francisco’s infamous fog sent many ships crashing against the headlands’ rocky shoreline. It was moved to its current location in 1877.
This south-facing shoreline is colloquially named after its signature inky-colored sand.
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