Medical scan used to unlock secrets of fossilized oyster

September 08, 1991|By Los Angeles Daily News

LOS ANGELES J — LOS ANGELES -- Dan Davis hopes a giant pearl is inside a 12-pound oyster he found on a Southern California mountain, but scientists say the hiker's enthusiasm over his discovery has already produced a pearl of wisdom.

In hope of finding a pearl, the 38-year-old salesman from suburban Northridge requested X-rays of his fossil at Holy Cross Medical Center in nearby Mission Hills.

Hospital officials one-upped Mr. Davis by doing a CAT scan -- computerized axial tomography -- which a Los Angeles scientist said apparently was among the first times that such imaging had been used on a fossil millions of years old.

Mr. Davis and hospital officials said last week that the filmed images showed two objects that possibly could be pearls, one about a quarter-inch in diameter and the other about three-fourths of an inch in diameter.

"I'm not convinced either of them is a pearl," said George Kennedy, curator of paleontology at the Los Angeles County Museum of Natural History.

"The real discovery might be the potential technique for studying other groups of fossil organisms," he said. "What was unusual about this was he had CAT scans done."

Doctors and nurses use the hospital's $750,000 computer device to produce cross-section filmed images of the brain and other human organs. The computer also clearly shows the cracks and fractures in the oyster, which is about 16 inches long and about 6 inches wide.

"Here's a method of looking on the inside of specimens without destruction," the paleontologist said. "I'm pretty confident it hasn't been applied [to fossils] anywhere, according to published records."

Mr. Kennedy says that even if the oyster does contain a pearl, it's probably not a gem.

"It would not be the type of thing in a jewelry store. It wouldn't have the beauty we associate with a pearl," he said.

Mr. Kennedy said the size of the mollusk -- which remains from a period when much of Southern California was under water -- was not unusual. He said similar fossils, some up to 2 feet long, have been found in the area.

Mr. Davis said he found the fossil this summer on a weekend hike in the Bouquet Canyon area, near the suburban city of Santa Clarita.

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