Basaltic breccia with limestone matrix:
basaltic fragments thrown into air, landed in
pond water inside volcano,
and settled into calcacerous mud
This rock is displayed in
“Sibley's Geological
Treasures” collection on the roofed patio of the visitor
center in the Robert Sibley Volcanic Regional
Preserve. The above caption is the same that is given on-site
(June 11, 2012).
Basaltic breccia is a rock composed of
fragments of basalt
and other rocks cemented together.
Breccias are found in the Berkeley Hills including the preserve's
Round Top, which was once the infilling of
a crater.
