Friday Field Foto #15: Pillow basalts

One of the best parts about living in the San Francisco Bay Area is that there is great geology very close by. I snapped this photo just a couple weeks ago when we showing some out-of-town visitors around the area.

These beautiful pillow basalts are exposed out at Point Bonita, which is the most seaward promontory adjacent to the Golden Gate. Barely visible is a seagull in the upper left corner of the photo for scale. This area is part of the Marin Headlands, which is composed of rocks of the Franciscan accretionary complex. Very near to this site are spectacularly folded radiolarian cherts.

In addition to the pillow basalts, which are obviously the main attraction, there is a cool old lighthouse.

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