LOS ANGELES (Reuters) - The ancient bones of a woman found on a California island appear to be the oldest discovered in North America and could change the theory of how humans first arrived on the continent, the Los Angeles Times reported Sunday. The two thigh bones were unearthed 40 years ago on Santa Rosa Island off Santa Barbara and languished in storage until scientists used newer techniques to test their age, the newspaper said. The surprising result was that the bones appeared to about 13,000 years old, 1,400 years older than previously thought, an age that would make them the oldest human remains found in North America, the newspaper said. The findings added to other recent discoveries that are forcing anthropologists to rethink the theory that humans arrived in North American about 11,500 years ago at the end of the last ice age, it said. Scientists believed the first North American inhabitants walked from Siberia to Alaska across a swath of land now covered by the waters of the Bering Strait then moved south and east across the continent. But the Santa Rosa woman seems to point to maritime colonisation, possibly by Polynesians or South Asians, the newspaper said. "Bottom line is she may be the earliest inhabitant of North America we have discovered. It‘s a find of national significance," the newspaper quoted John Johnson, curator of anthropology at the Santa Barbara Museum of Natural History and a member of the team analysing the remains, as saying. Other ancient remains dug up around the United States have also sparked controversy because the skeletons do not resemble those of modern Native Americans but of Caucasoid peoples instead.