At Caldecott Tunnel Dig, Paleontologists Want Fossils, Caltrans Wants to Finish
Caltrans is trying to finish the fourth bore of the Caldecott Tunnel within the next two years, in order to ease traffic congestion in the East Bay. But paleontologists on the project say they aren’t being given enough time to preserve important fossils.At both ends of the new tunnel, crews grind rock 24 hours a day. Outside the dig, trucks dump literally tons of material. That’s where you’ll find paleontologist Kristen McCallister, small hammer in hand, sifting through the piles.
“I just pretty much find a big rock or little, depends, and start breaking off the edges,” McCallister says, hammering a piece of siltstone. “We could find a whale in here or little tiny fish bones that are maybe half a centimeter.”
Caltrans is drilling through rock layers that were deposited between five and 11 million years ago, during the Miocene Epoch. It’s a time when the Bay Area was home to prehistoric camels, rhinoceros and horses.
“We found a wolverine. Not the sort of wolverine you would think about modern day. This wolverine was bigger than a grizzly bear,” says McCallister.
So far, about 2000 fossils have been found, which will end up in UC Berkeley’s Museum of Paleontology. (See photos here.). McCallister says the fossils provide clues about how animals evolved and what the climate was like. “So you can see how things have changed and possibly how things are going to keep changing.”McCallister says if she’s lucky she can go through about 10 percent of the rock. At first Caltrans agreed to allow at least two paleontologists on site. But a new report prepared for Caltrans calls for just one.
“Pretty unacceptable, put it that way,” says Lanny Fisk with PaleoResource Consultants. Caltrans hired his firm to recover the fossils–preservation work that’s required by state and federal environmental laws.
“One person cannot watch excavations at both ends of the tunnel. That’s resulting in a lot of loss of fossils,” he says. Fisk is also upset because back in December, Caltrans told him to stop preparing, identifying and analyzing the fossils, and hasn’t indicated when that work can continue.
“It’s critical that this project is completed on time and within budget,” says Caltrans spokesperson Ivy Morrison. Morrison says at its core, the project is about road construction. Caltrans has done its best to accommodate the scientists, she says, but there are budget concerns. “It wouldn’t be possible to go through everything, regardless of how many people you have. She [McCallister] is getting representative spoils and that’s adequate.” Morrison says they’re currently tunneling in a rock formation that’s less scientifically relevant, so only one monitor is needed.
Caltrans plans to drill through all the rock formations again, since the bottom half of the tunnel has yet to be excavated. Fossil collection will continue through the fall, until both sides of the tunnel’s top half are joined. Caltrans says it hasn’t decided if the paleontological work will continue after that.