Who Were The First Americans?

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That's the story textbooks told for decades--and it's almost certainly wrong. The first cracks in the theory began appearing in the 1980s, when archaeologists discovered sites in both North and South America that seemed to predate the Clovis culture. Then came genetic and linguistic analyses suggesting that Asian and Native American populations diverged not 12,000 years ago but closer to 30,000 years ago. Studies of ancient skulls hinted that the earliest Americans in South America had different ancestors from those in the North. Finally, it began to be clear that artifacts from Northeast Asia dating from just before the Clovis period and South American artifacts of comparable age didn't have much in common with Clovis artifacts.

Those discoveries led to all sorts of competing theories, but few archaeologists or anthropologists took them seriously until 1997. In that year, a blue-ribbon panel of researchers took a hard look at evidence presented by Tom Dillehay, then at the University of Kentucky, from a site he had been excavating in Monte Verde, Chile. After years of skepticism, the panel finally affirmed his claim that the site proved humans had lived there 12,500 years ago. "Monte Verde was the turning point," says David Meltzer, a professor of prehistory at Southern Methodist University in Dallas who was on the panel. "It broke the Clovis barrier."

Why? Because if people were living in southern Chile 12,500 years ago, they must have crossed over from Asia considerably earlier, and that means they couldn't have used the ice-free inland corridor; it didn't yet exist. "You could walk to Fairbanks," says Meltzer. "It was getting south from Fairbanks that was a problem." Instead, many scientists now believe, the earliest Americans traveled down the Pacific coast--possibly even using boats. The idea has been around for a long time, but few took it seriously before Monte Verde.

One who did was Jon Erlandson, an archaeologist at the University of Oregon, whose work in Daisy Cave on San Miguel Island in California's Channel Island chain uncovered stone cutting tools that date to about 10,500 years B.P., proving that people were traveling across the water at least that early. More recently, researchers at the Santa Barbara Museum of Natural History redated the skeletal remains of an individual dubbed Arlington Springs Woman, found on another of the Channel Islands, pushing her age back to about 11,000 years B.P. Farther south, on Cedros Island off the coast of Baja California, U.C. at Riverside researchers found shell middens--heaps of kitchen waste, essentially--and other materials that date back to the same period as Daisy Cave. Down in the Andes, researchers have found coastal sites with shell middens dating to about 10,500 years B.P.