Researchers at the UC Museum of Paleontology, or UCMP, at Berkeley have been given more than 1,500 specimens — including 25 whale skulls — that were discovered at the Calaveras Dam.
The specimens, which date back roughly 15 to 20 million years, were found during the Calaveras Dam Replacement Project. The project, which aims to retrofit the dam, started in 2011 and is scheduled to finish April 2019, after which paleontologists will no longer be able to excavate the site.
The fossils were found while excavating nearly 9 million cubic yards of soil for the dam replacement, according to Betsy Lauppe Rhodes, the San Francisco Public Utilities Commission, or SFPUC, Sunol regional spokesperson. Rhodes said most of the fossils have been discovered and removed, but new specimens continue to be found.
“We had no idea we would find this many,” Rhodes said. “We had no idea we would find this depth and this breadth, but it’s been an amazing journey for us.”
The fossils have since been transported to UC Berkeley, where they are currently being prepared and identified by graduate and undergraduate students in the UCMP in the bottom floor of the Valley Life Sciences Building. Campus graduate student Mackenzie Kirchner-Smith, who assists in the UCMP lab, said all of the fossils will eventually be put into the UCMP.
“I think it gives us a good picture about what this part of California looked like during a warmer time,” Kirchner-Smith said. “It also is an awesome opportunity for students because it gives graduates and undergraduates a cool opportunity to work on this stuff, and what the area was like, and what kind of fossils were here.”
Independent paleontologist Jim Walker, who was hired to monitor the excavation site, said fossils had been found in the area around the dig, so the discoveries at the dam weren’t a “total surprise.” He added, however, that fossils from this time period are not commonly found at other excavation sites in the East Bay, making this collection of fossils “very much unique.”
Kirchner-Smith expressed a similar sentiment, remarking on the rareness and scope of the find.
“This is the very first time that this time and place have been explored, in terms of the fossil record,” Kirchner-Smith said. “It’s kind of the trifecta of fossil finds: we have trace fossils, vertebrate fossils, invertebrate, plant fossils. Usually you (find) one, maybe two of those things and this one has all. … So the diversity of life is really incredible as well.”
Scientists so far believe they have discovered the remnants of a new species of whale at the dig site, according to Kirchner-Smith, in addition to large scallops, shipworms — a type of wood burrowing clam — and other terrestrial fossils.
The discovery of these fossils, according to both Walker and Kirchner-Smith, suggest that 15–20 million years ago, the Bay Area was at least partially underwater and likely in a warmer climate.
Walker added that the discovery could have further implications on how we approach today’s changing climate.
“One of the important things we learned is how animals adapted and evolved when they’re faced with climate change,” Walker said, “Which, of course, is something everyone is concerned about these days.”
