Stone tools suggest earlier human presence in North America – study

Stone tools found in a Mexican cave suggest that people were living in North America as early as about 26,500 years ago, much earlier than most scientists accept, a study says. It is a new step in the difficult and contentious process of establishing when people arrived in North America from Asia. Presently, the most widely accepted dates for the earliest known North American archaeological sites date to before 15,000 years ago and extend maybe to...