LOS ANGELES —
"We're still trying to piece everything together," he said.
Harris estimated it will take five years to sort through the crates. The museum has placed a priority on getting the above-ground excavation done, so it temporarily halted work on Pit 91 where scientists have been pulling out bones since 1969.
The tar pits located 7 miles west of downtown Los Angeles are a paleontological gold mine. Asphalt bubbled upward through cracks and fissures over the millennia, trapping Ice Age beasts that later starved to death. Once a large mammal was bogged down, predators would approach, followed by scavengers and insects, which would also get stuck.
Before this latest dig, more than a million bones have been recovered from the sticky ponds.
In the new work being carried out just north of Pit 91, researchers hopscotch between two tarp-covered crates, which have been divided into grids to help pinpoint the exact position of fossils.
Digging in the larger box one recent morning as a group of schoolchildren peered through a fence, chief excavator Carrie Howard and colleague Rice scraped away dirt from a deposit containing a hodgepodge of specimens including horse, saber-toothed cat and dire wolf.
Unlike the underground excavations, the bones in the crates are encased in hard dirt as a result of sitting out in the sun for two years.
To get around the problem, Rice uses a dry cleaning solution to soften the asphalt mixture. Others improvise by using heat lamps.
Once fossils are extracted — a process that can take months — they are shipped to the museum lab where they are cleaned, identified and, in some cases, put on display. The current project is expected to double the museum's Ice Age collection.
As excavators toiled outside, lab workers continued their examination of the skull of Zed, the Columbian mammoth skeleton that was found nearly complete.
Later in the week, the museum plans to open up another crate for study.