Ancient Find Helps Unravel Past : Discovery: Woven fragments on San Miguel Island are expected to give scientists insight into sandal- and basket-making among settlers at least 8,600 years ago.

Digging in a cave on San Miguel Island, anthropologists have discovered the fragments of what they believe was a child’s sandal woven of sea grass 8,600 years ago by the ancestors of the Chumash Indians.

A team of anthropologists found two woven fragments and hundreds of pieces of cord, which radiocarbon tests have dated at between 8,600 and 9,800 years old--twice the age of any other woven artifacts on the Pacific Coast.

“The antiquity of this find is unparalleled,” said Jon M. Erlandson, a University of Oregon anthropologist. “I’ve spent 20 years excavating sites in the area and I’ve never found basketry until this discovery.”

Ancient baskets and other woven materials are particularly rare in coastal areas because moisture tends to accelerate their disintegration. Sea grass is a tough, fibrous material, but like any organic material it will break down over time.

Erlandson and other anthropologists theorize that the sea grass was uniquely preserved by the high salt content of sea bird guano that buried the fragments. “It’s extremely salty; it’s like a pickle deposit,” Erlandson said. “It’s so salty that none of the microbes can attack it like they normally would with organic matter.”

Normally, rainwater would flush the salt from the soil. But the artifacts were deep enough inside the cave that they were protected from rainfall.

Cormorants and other fish-eating sea birds roost in the cave on the island, situated about 60 miles off the coast of Ventura County.

When European explorers reached the New World, Native American tribes in California produced some of the most accomplished and artistic basketry in America.

But archeologists have had difficulty chronicling the development of weaving tradition outside of the desert areas, which have dry climates that help preserve such artifacts.

Remains of baskets have been found at a number of sites on the Channel Islands, including woven artifacts with asphalt used to waterproof baskets.

Until the discovery on San Miguel Island, the oldest evidence of basket-making along the California coast was dated between 3,500 and 4,500 years ago.

In addition to the two palm-size fragments, researchers found 400 pieces of cord, spun strands of sea grass that may have been used for fishing line, and fishing nets or baskets.

“It is mind-boggling to find this material from such a long time ago,” said Don Morris, staff archeologist with the Channel Islands National Park.

He said the remnants give scholars a keen insight into the technology of making baskets and sandals among the earliest settlers in the area.

Morris said the seafaring people who inhabited the Channel Islands at the time were the ancestors to the Chumash, just as the Mesolithic hunters in Europe were the forbearers of the French and the English.

When the fragments were found during excavations from 1991 to 1994, they looked like a matted bunch of trash, Morris said. Erlandson carefully removed the material to sort out later.

Only after a great deal of study, Morris said, did archeologists confirm the significance of the artifacts.

“You might think it is a pile of scrap,” Morris said. “But the key to all of this is very, very careful work.”