CRAWLEY, AUSTRALIA—People are known to have arrived on Australia's northern shore around 65,000 years ago. Now, according to a Science Magazine report, artifacts and traces of ancient campfires suggest that people first migrated to the continent's Western Desert at least 47,000 years ago, about 10,000 years earlier than previously thought. A team led by archaeologists Peter Veth and Jo McDonald of the University of Western Australia found charcoal, thousands of stone tools and other artifacts, and rock paintings of snakes, turtles, and human figures at Karnatukul, a rock shelter in a subregion of the Western Desert known as the Little Sandy Desert. “Fifty thousand years is the limit for radiocarbon dating,” McDonald said, “so we really are at the edge of the barrier, and that’s why it’s possible this site is even older.” Critics of the study, however, say it is hard to know whether the charcoal at the site was made by people. For more on archaeology in Australia, go to “Death by Boomerang.”