SAN FRANCISCO (KPIX 5) — We’re getting our first look at fossils that range from between 15 and 20 million years old recently discovered in the San Francisco Bay Area.

Construction crews discovered hundreds of fossils while working on the Calaveras Dam.

Experts have descended on the site and among the discoveries is a brand new whale species, scientists say.

It’s a treasure trove of history, but researchers only have a limited time to clean and categorize the artifacts.

Dr. Cristina Robins is a senior museum scientist at the University of California’s Museum of Paleontology and she said paleontologists have one shot at this.

Dr. Robins said, “So, the dam is being constructed, everything is being covered in concrete or excavated out, or will be flooded with water. So, this is a one-time only deal. The fossils that we have here are unique and there’s not another opportunity to get them.”

Read Also: Calaveras Dam Project Fossils Provide Glimpse Of Prehistoric Bay Area

Graduate assistant Mackenzie Kirchner-Smith showed us bones that were the backbone of a whale.

Undergraduate student Laura Mackenzie said she was amazed that she was allowed to help out on this undertaking.

Mackenzie said, “When I saw it on the work-study, I was like: Really? Undergraduates are able to do this? And I wasn’t really sure if I was able to get the position or not. But I did, thank God!”

Robins said, “You have to take a step back and realize that, hey you’re the first person to see this, ever, pretty much.”

From these fossils, they are learning a lot about our Bay Area’s climate millions of years ago  and how we can adapt to our changing climate in the future.

Dr.Robins said, “We are warming up. Our sea level is rising. And we can see what the animals were doing back then, what was going on in the ocean and we can maybe use that to figure out a way to deal with the upcoming change.”

Undergraduate student Laura Mackenzie said, “It’s truly humbling. It really humbles you and kind of makes you think about our species and our current planet and everything, and what’s happening.”

Researchers say from these fossils they know the Bay Area was underwater and much warmer millions of years ago.

If you want to check out some of the fossils, the Valley Life Science building will be open to the public this Saturday for Cal Day at University of California at Berkeley.