`The ultimate cold-case file'
Meet the fossil hunter protecting history at construction sites
During the last Ice Age, the Bay Area was a vast river valley roamed by mammoths, saber-toothed cats and giant sloths. Many of them are still down there in the ground in fossil form, only to be discovered when construction crews dig for projects like skyscrapers and transit tunnels.
These ancient remnants have scientific value and, as Indiana Jones would say, belong in a museum. That's where people like Jim Walker come in. Walker is a senior paleontologist/geologist for Applied Technology & Science, a San Francisco engineering and environmentalconsulting firm. His job is to monitor construction sites for fossils and, when they're discovered, quickly get them out of the dirt and into safe storage.
Walker has worked on some of the largest government and private projects in the
Bay Area, from the $2.2 billion Transbay Transit Center in San Francisco to the $810 million Calaveras dam seismic retrofit and Samsung's $300 million corporate headquarters in San Jose. He monitors many Caltrans projects and has helped shepherd fossils from those digs to public exhibits at the Children's Natural History Museum in Fremont.
It's the sense of mystery that has kept Walker engaged in his job for the last 14 years.
“I often joke that with the whole paleontological thing, it's like the ultimate cold-case file,” he says. “You're coming across an animal that's been dead for 10,000 years, and you're trying to get a little picture of what its life was like — and also what that world looked like.”
Walker recently took time from his home fossil-study station — complete with drafting table, microscope, dental tools and soon, an air scribe — to chat about the rigors and importance of his work.
Q
Can you explain what you do in a nutshell?
AIt's probably best characterized as “salvage palaeontology.” This work is really all around the CEQA requirements — that's the California Environmental Quality Act. Fossils are considered a nonrenewable scientific resource. So what I do is collect any fossils deemed scientifically significant and get them to a museum or something like that. And this is always work that's related to a construction project.
Q
Have you ever had to halt a construction project?
A
I have never had to halt construction. We have redirected work sometimes. My job is to keep my client in compliance, so they don't run afoul of any agencies that would be watching this stuff. If we have determined there is a possibility of them damaging these nonrenewable scientific resources, our job is to mitigate that, which usually means getting the stuff out of the ground as quickly as we can.
Q
Why quickly?
ASo those machine operators do not sit idle for hours, waiting for someone to come and tell them, “Yeah, this is a fossil and we should do something about it.” Or (conversely), “You have found an interesting-looking rock.” You got to remember that having equipment sit idle can run into the tens of thousands of dollars very quickly. So we are a cheap insurance to keep them in compliance.
Q
What types of things do you find?
A
Typically, most of our stuff is from Pleistocene or “Ice Age” time (from 2.6 million to 11,700 years ago). Depending precisely on what we're talking about, there wasn't a Bay back then. The Bay was a big valley with a river running through where the Golden Gate is and meeting the ocean just past the Farallon Islands. Across that field, we had mammoths, bison, camels, giant sloths and a lot of animals we recognize today — deer, coyotes, brown squirrels and rabbits.
Q A
Have you ever dug up human bones?
With any bone that's possibly human-sized, the first thing I do is call a specialist in human osteology. I can get in as much trouble as anybody else on the job site for messing around with human remains.
Q
Because it could be a crime scene?
A
That's the thing most people don't get. The first question is, “Is this a homicide?” Or they can be Native American (bones), and then there's a whole protocol to deal with that.