On a clear day, the view from the top of the Campanile is spectacular and gives a good overview of the local geology. The geologic history of Berkeley's campus spans 150 million years. In the surface outcrops and cover we observe mostly unconsolidated sediments that are composed of volcanic rocks of the Berkeley Hills (basalts 15-20 million years old). San Francisco Bay, which is fairly recent in geologic terms (~10,000 years old), was flooded during the last glacial retreat. The Bay is composed of three parts, the south, central, and north. The northern section, the San Pablo Bay, is the site of approximately 4km of sedimentary accumulation over the last 20 million years. Just beyond the Golden Gate Bridge lies the San Andreas Fault, and beyond that, the Farallon Islands. Whatever rocks are now on the other side of the San Andreas Fault originated as much as 300 miles to the south.