Stone tools suggest earlier human presence in North America

NEW YORK (AP) — Stone tools from a Mexican cave suggest people were living in North America much earlier than most scientists think.  Researchers reported Wednesday that the tools date to as early as 26,500 years ago, about 10,000 years before the generally accepted date for the earliest human presence in North America.  The researchers said ancient people might have used the cave as a winter shelter for short periods of time. But an anthropologist not affiliated with the study s