Scientists are taking a new look at an old and controversial idea: that ancient Polynesians sailed to Southern California a millennium before Christopher Columbus landed on the East Coast. Key new evidence comes from two directions. The first involves revised carbon-dating of an ancient ceremonial headdress used by Southern California's Chumash Indians. The second involves research by two California scientists who suggest that a Chumash word for "sewn-plank canoe" is derived from a Polynesian word for the wood used to construct the same boat.