Since 1875, paleontologists have unearthed more than 3.5 million fossils from the tar pits. Each find provides clues about California’s past. For example, scientists have uncovered fossils of plants that live only in cold or foggy areas. That means that L.A.’s climate was much cooler and wetter thousands of years ago.
At the new subway site, across the street from the museum, workers don’t want to damage any buried fossils. So the city hired monitors—people trained to look for fossils during construction. They watch the dirt as machines dig.
“Most people probably wouldn’t notice a fossil. It’s the same color as the dirt,” says Ashley Leger. She’s the paleontologist overseeing the process. “Monitors know the texture and shape of bones,” she says.
Construction workers take extra care too. On most projects, they use an excavator’s big claw to dig 1 meter (3 feet) deep with each swipe. At this site, they dig just 15 centimeters (6 inches) at a time. “If it weren’t for this process, the fossils would be in a million pieces,” says Leger. “We want them to be saved for people from all over the world to study.”