Duxbury Reef
Excellent tide-pooling can be had along the 3-mile shoreline of Duxbury Reef; it's one of the largest shale intertidal reefs in North America. Look for sea stars, barnacles, sea anemones, purple urchins, limpets, sea mussels, and the occasional abalone. But check a tide table ( usharbors.com) or the local papers if you plan to explore the reef—it's accessible only at low tide. The reef is a 30-minute drive from the Bear Valley Visitor Center. Take Highway 1 South from the center, turn right at Olema Bolinas Road (keep an eye peeled; the road is easy to miss), left on Horseshoe Hill Road, right on Mesa Road, left on Overlook Drive, and then right on Elm Road, which dead-ends at the Agate Beach County Park parking lot. Avoid areas rich with fragile Monterey shale, which are prone to erosion from human disturbance. It is illegal to collect anything from this protected marine area.