Phil Orr is responsible for finding the remains of the Arlington Springs Woman forty years ago; They are the oldest remains found anywhere in North or South America.

Forty years ago, Phil Orr started a revolution when he discovered the remains of Arlington Springs Woman on California's tiny Santa Rosa Island -- not that he knew it at the time. Recently dated at more than 13,000 years old, hers are the oldest human remains found anywhere in North or South America. Their existence has helped turn traditional thinking about the identity of the first Americans on its head.

Scientists always thought that the first Americans were big game hunters, called Clovis people, who walked down from Alaska into the center of the North America at the end of the last Ice Age--about 13,000 years ago. But Arlington Springs Woman, from people who must have been living off the sea, suggests the Clovis-First theory may be wrong.

So who were these people fishing off the coast of California? And how and when did they get here?

A scan of the Arlington Springs Woman bone shows fusion lines indicating she was full-grown.

Alan meets archeologist Jon Erlandson, who thinks that Clovis people may have came down the coast and moved to the interior of the continent instead of spreading from the center outward. It's clear that Arlington Springs Woman must have had a boat, just to get to Santa Rosa Island. But even that's a new idea. As Erlandson explains, scientists have only recently learned that people had boats capable of offshore travel as early as 50,000 years ago.