Sibley Volcanic Park

Geology of Sibley Volcanic Park

This field trip will be to Robert Sibley Volcanic Regional Preserve, one of the original three parks established in the East Bay Regional Parks District, along with Tilden and Temescal (link). The park was originally called Round Top, a reference to the ancient volcano that forms the highest peak in the area, and which is the focus of this trip. The rocks here tell a dramatic history of the East Bay Hills, where megafauna roamed a landscape with shifting river beds and occasional lava flows. On your visit to Sibley, you will be able to peer inside an extinct volcano to fathom several millions years of local history in a way that is not possible elsewhere in California. Follow along with the AllTrails map.