Something to Dig Into

“Everything’s covered in tar,” said 6-year-old Nathan Hoshizaki as he and his two brothers peered into Pit 91 at the La Brea tar pits.

Everything, indeed. The walls, the floor, the ladder, the people--anything and anyone that ventures into the dark, gaping hole in the middle of Hancock Park is at least smudged, if not unceremoniously coated, in black, sticky asphalt.

The preoccupation with cleanliness, however, is quickly wiped away as Nathan and his family, from behind the glass at the Visitor Observation Station, realize the gooey prehistoric grave is jam-packed with fossils popping out all over the place.

“My wife and I were going to take the boys to the Page Museum [of La Brea Discoveries],” said Nathan’s father, David Hoshizaki. “And this is neat, to first see how it all got there.”

The public can watch for free, Wednesdays through Sundays through Sept. 7, as workers brush and dig with tiny tools, carefully scraping away the asphalt (commonly referred to as tar) from the big bones and tiny teeth in a 3-foot square of the 14-foot-deep pit.

Paleontologists and volunteers can’t work fast enough to extract the Ice Age fossils. Thousands of specimens have been excavated from this one location of the former Rancho La Brea (Tar Ranch), a 23-acre property donated to the county in 1924. It’s estimated that 4 million fossils, dating back 10,000 to 40,000 years, have been recovered. Because of the saturation of the asphalt, the fossils are “preserved as bone here rather than being minerally replaced or petrified.”

“Working on this stuff, we have the ability at any time to pick up something no human being has ever touched before,” said Jerry Smith, one of two paid excavators.

Since excavation resumed during the 1984 Olympics, paleontologists and volunteers return to Pit 91 for two months each summer--the amount of time that funding allows. Sporting hard hats and sitting on upturned buckets, the workers sift through piece after piece of a puzzle to the past.

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On opening day of this summer’s excavation, one reporter wandered over to a circular area framed by wooden planks, its shiny black surface mostly obscured by a thin layer of dust and leaves. An unseen sticky patch no thicker than flypaper grasped the reporter’s foot, at the edge of what turned out to be Pit 10.

“This shows how animals got trapped,” said John Harris, director of Page Museum. “It’s all rather innocent-looking.”

Over a period of 40,000 years, Harris explained, the asphalt would heat up in the hot summers and get sticky, and leaves and debris would camouflage the hazardous tar pool. An animal would walk into the patch--and a feeding frenzy would follow.

“It only takes 2 to 3 inches to totally immobilize a cow or bison,” Harris said. “In would come a saber-toothed cat to feed on the bison, and he’d get stuck. The vultures would come, and they’d get stuck. Then come the insects, and that’s how it built up. Pretty soon, you have a fair sprinkling of the local population.”

And that’s why, Harris added, there are piles of bones--and very few complete skeletons--in the pits. The pits are, of course, a gold mine for information about early life in L.A.

In the original excavation of Pit 91 (1913-15), researchers were only interested in big bones. Today, Harris said, everything that comes up is examined, down to the minutest particles. That’s one reason why the process is so painstakingly slow.

“Our aim is not to go for the trophy specimens,” Harris said, “but to find out what we can about the environment.”

A smaller find may not be as visually impressive as a saber-toothed cat or a giant ground sloth, but it does offer a lot more information to researchers. “A saber-tooth would wander hundreds of miles,” Harris said. “A land snail would not. The smaller critters, the wood, seeds and insects, tell us a lot more about the climate in the L.A. Basin. It was once a lot cooler and wetter than today.”

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During the next couple of weeks, buckets of asphalt and fossils will be hauled into the paleontology lab inside the Page Museum. The lab, referred to as “the fish bowl,” is a glassed-in room where museum visitors can watch researchers and volunteers at work.

Nic LeCorvec, a 16-year-old Loyola High School student who lives nearby, used to spend many hours gazing at the museum’s fossils of mastodons, saber-toothed cats and mammoths from the other side of the glass. Now he’s a museum volunteer. Dressed in a white lab coat, he picks away at the matrix (asphalt and other debris attached to a fossil) that is stuck to a horse’s leg bone.

“It’s pretty cool,” LeCorvec said, as he used solvents, a toothbrush and dental pick to separate debris from the bone. “I always wanted to see what it was like behind the counter.”

Lab workers are surrounded by tables covered with hundreds of bones, many dug from the pit as early as 1908, some from days ago. Each bone or fragment awaits cleaning, categorizing and filing, all pieces to a giant puzzle that, admits lab supervisor Shelley Cox, may never be complete.

After 96 volunteer hours in the lab, workers 18 and older earn the chance to descend into Pit 91 to do excavation. LeCorvec is two years shy of the age limit, but he likes the work he does now, he said.

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Besides, there’s no rush. According to Harris, there is another 8 to 10 feet to go in the excavation of Pit 91. Even if the work continued year-round, it would probably take about five years to empty the pit of all its specimens. But, as Harris points out, if the work continues at the current pace, “it will probably take another 20 years.” And that’s just one pit.

There is a high potential for deposits around Hancock Park yet to be excavated, Cox said. For years, asphalt has seeped into neighboring basements and parking lots (Hancock Park lake was once an asphalt mine), and bones have been discovered during construction across the street.

“We know there’s a deposit of bones in the westbound traffic lane on Wilshire, opposite the bus stop,” said Cox. While it’s unlikely that traffic will be brought to a halt for a dig any time soon, Cox isn’t worried about the bone field beneath it. “It’s not going anywhere,” she said with a laugh.

BE THERE

Hancock Park and Page Museum of La Brea Discoveries, 5801 Wilshire Blvd., Los Angeles. Admission to Visitor Observation Station is free; museum admission, $6; students and seniors, $3.50; ages 5-12, $2. To become a laboratory volunteer, call (213) 857-6322. Pit 91 open 10 a.m.-4 p.m. Wednesday-Sunday through Sept. 7.