UC Berkeley researchers are using an exceptional stash of fossils found during the construction of a new East Bay dam to piece together a picture of what the Bay Area may have looked like some 15-20 million years ago.
Water covered much of the region, extending down the Central Valley as far as Bakersfield. Ancient whales sifted food through baleen over what is now Berkeley and Oakland, while now-extinct megalodon sharks might have hunted dolphins over San Jose. Hippo-like creatures waded along the coast, which was dotted with palm and pine trees. Seals, larger than today, frolicked in the water.
Researchers have new evidence of all of this thanks to remarkable collection of at least 1,500 fossils that were found and preserved starting in 2013, when the San Francisco Public Utilities Commission began heavy excavation to construct a new dam to replace the existing 93-year old Calaveras Dam that is seismically vulnerable.
The massive project sent workers moving almost 10 million cubic yards of rocks and soil, where they unearthed one of the most complete collections of Bay Area fossils found in more than 50 years.
“We had expected to find some fossils during construction, but we had no idea the team would find this many,” said Dan Wade, SFPUC Director of Water Infrastructure Capital Projects and Programs. “It was extremely important to us to keep the collection together, to keep them in the Bay Area, and to be able to make them available for scientific research.”