Calaveras Dam fossil discovery could be new whale species

Image 1 of 7

A new species of whale is believed to have been discovered in one of the biggest fossil finds in the Bay Area.

Dr. Cristina Robins, Senior Museum Scientist with the University of California, said the fossil is among roughly 2,000 that have been unearthed over the past several years by construction crews at the Calaveras Dam Replacement Project. She and several students have been working for more than a year inside a fossil lab at UC Berkeley to prepare the fossils that are believed to be 10 to 15 million years old.

The San Francisco Public Utilities Commission is seismically retrofitting the Calaveras Dam which sits near the active Calaveras fault line on the border of Alameda and Santa Clara counties. Since 2011, construction crews have moved nearly 10 million cubic yards of earth and rock, equivalent to fill Levi’s Stadium three times, according to the SFPUC. In that process, everything from whale skulls to a whale jaw, mussels, clams, snails, shark teeth, and more were discovered.%INLINE% 

“We’ve partnered with the SFPUC in order to get these fossils,” Robins said. “This find is incredibly special because we have a complete paleo environmental picture. We have all the plants, all the animals and it tells us a lot about the area.”

The most significant find so far is a new type of Baleen whale species. Robins said the ears of the whale are located differently on this skull, which makes them believe it is a new species. It has yet to be published. With more than 20 whale skulls left to prepare, Robins hopes to find more.

Xena Ross is a sophomore lab tech and an anthropology and political science double major. She regularly works on chiseling away rock to uncover the fossils and has taken an interest in the dozens of shark teeth that have been found. She noted the Bay Area was covered in water 15 to 20 million years ago.

“I work so much with shark teeth that I think I just picture a bunch of sharks running around beating each other up,” Ross said. “You find shark teeth in whales too so I imagine it was a pretty cut throat society.” 

Each relic is being prepped and cataloged for the UC Museum of Paleontology in an online database. It will take some time before the online database is available to the public. The fossils are quite alright staying put, but their history, hidden in stone, is worth the fight to dig them out.

“It’s just cool to see things that lived here millions of years ago,” Ross added.

Betsy Rhodes, SFPUC spokeswoman, said the specimens have been collected from the Claremont Shale and the underlying Temblor Sandstone Group, which are both from the Miocene epoch. 

Rhodes said it is not uncommon to find fossils in the Bay Area, but the concentration of such unique and varied specimens makes the Calaveras dam construction site special. The SFPUC does not expect to find any more fossils because crews have finished excavating. Plans are on schedule to finish the dam by this summer with full completion of the project in the summer of 2019.