A Natural Bonanza at Pit 91

Pit 91 has been shut down for the summer, and the season’s yield has been routinely spectacular.

Fossilized bones by the thousands. Enough to fill 15 five-gallon buckets. Skulls of saber-toothed cats and dire wolves at least 35,000 years old. Give or take a millennium.

Snails, seeds, diatoms, dung beetles that became extinct when mammoths (and obviously their dung) became extinct, and a heel bone from a small ground sloth.

“Only three heel bones have been found in this area,” George Jefferson enthused. “And all from the same spot, from Pit 91. Why? A good question. I don’t know.”

Why are long-dead sloths showing up minus their heel bones? How and by what were they detached?

Again, Jefferson can’t answer. But not knowing is his fodder. Discovering answers before questions have been asked is his raison d’etre --as assistant curator of the George C. Page Museum of the La Brea Discoveries, geologist, anthropologist, archeologist and straw boss of Pit 91.

His unique hole is built into a prehistoric pudding of asphalt that snagged its first victim during the Pleistocene Ice Age.

Opened in 1913, Pit 91 has grown from a small shaft to a 30-foot square, 400 centuries deep. For endless summers, beneath the gaze of countless visitors, the brushes and dental picks of scientists and volunteers have reclaimed fossilized bones of its dead. Eagles. Bats. Moles. Horses. Some 560 species. One million specimens.

The remains have been sorted, cleaned, restored and some of their original owners rebuilt for display at the Page. Or for scholastic shipment worldwide. This summer’s haul has been bagged for eventual sorting and identification in the museum’s laboratory, where glass walls allow public view.

Pit 91 is the best hole “in terms of numbers of specimens and . . . in terms of taphonomy (the process of fossilization) and the whole idea of how (Rancho) La Brea came about,” Jefferson explained. “In the world of paleontology, for its age, it’s the most abundant fossil site in the world. The diversity of life form. The concentration. The incredible degree of preservation.”

The payoff, he added, is immeasurable. To know what happened then is to predict what could happen again. If the conditions for extinction can be determined, repetition can be avoided.

“It (Pit 91) is a sample of an environment, as if nature reached back 30,000 years, grabbed a handful, gave it to us and said: ‘Here, see what you can make of this,’ ” Jefferson said.

In 1914, nature returned the remains of a 9,000-year-old human, a skull and a cluster of bones that became the La Brea Woman.

She appears behind glass at the museum. A neat sleight of holography transforms the young Indian from full, attractive form to stark skeleton. Except the skeleton is a cast, not the actual bones of the real La Brea Woman.

They are kept in a steel locker behind museum scenes. It has to do with study requirements, the decency of exhibiting human remains and the inescapable fact that for display purposes, a full skeleton tells a better story than one skull and parts.

“We only have about 10% of her,” Jefferson said.

Yet, it is a fascinating percentage that has told much.

The woman was young, between 22 and 25. She likely was placed in a temporary grave before exhumation and transfer to the tar pit. It was a ceremonial reburial. A pet dog was buried with her.

And she may well have been Los Angeles’ first known murder victim. Cause of death is believed to have been a blow to the head that fractured the left side of her skull, cheek and jaw.

“Poor kid,” said Jefferson. “She had all kinds of problems.” He pointed to a molar. “An impacted wisdom tooth. An incisor that grew inward.

“Then someone came along and bashed her head in.”

George C. Page Museum of the La Brea Discoveries, 5801 Wilshire Blvd. Closed Mondays and Tuesday. Taped information: (213) 936-2230.