Major cache of fossils unearthed in L.A.

Because of the historic nature of the area, the work had to be overseen by a salvage archaeologist. In this case, the work fell to Robin Turner, founder of ArchaeoPaleo Resource Management Inc. of Culver City, which previously had overseen work on other sites at or near the tar pits. Her group hit pay dirt when the excavation got about 10 feet below the surface.

"I knew we would find fossils . . . but I never expected to find so many deposits," Turner said. "There was an absolutely remarkable quantity and quality."

There were 16 separate deposits on the site -- an amount that, by her estimate, would have taken 20 years to excavate conventionally. But with LACMA officials prodding her "to get those things out of our way" so they could build their garage, she had to find another way.

Her solution was a process similar to that used to move large living trees. Carefully identifying the edges of each deposit, her team dug trenches around and underneath them, isolating the deposits on dirt pedestals. After wrapping heavy plastic around the deposits, workers built wooden crates similar to tree boxes and lifted them out individually with a heavy crane. The biggest one weighed 123,000 pounds.

"We designed a crate so that we could take out the entire deposit without disturbing it so that, at a later date, you could do a proper excavation as you would if it were still in the ground," she said.

In 3 1/2 months, working seven days a week, she and her colleagues removed the entire collection two years ago and delivered them to the museum. For some of the deposits, she said, they had to wear oxygen tanks with full gas masks because of unusually high levels of hydrogen sulfide escaping from the soil.

The only exceptions to the crating process were the mammoth named Zed and a horse skull. Because they were separate from the other assemblages, they were partially excavated and encased in plastic casts for cleaning in the museum -- the conventional technique for recovering fossils.

Curators are excited about Zed because he appears to be about 80% complete, missing only one rear leg, a vertebra and the top of his skull, which was shaved off by excavation equipment.

Curators collected 34 mammoths in the initial excavations of the La Brea tar pits from 1906 to 1914. "But they were all disarticulated bones, jumbled together," said paleontologist Christopher A. Shaw, collections manager at the Page. Mammoths on display at the museum are assembled from the bones of many animals.