A South Carolina archeologist says he has evidence that humans were camping along the Savannah River 50,000 years ago, long before most researchers believe our ancestors reached this continent.

Albert C. Goodyear III of the University of South Carolina has excavated what appears to be a hearth in the lower levels of the famous Topper site in a South Carolina quarry where researchers have been digging for more than 20 years. The presumed hearth contains what appear to be primitive stone tools, primarily flake knives and hammers.

Radiocarbon dating of charcoal remnants from the hearth performed by a team at the University of California, Irvine show that they are at least 50,000 years old, which would make the artifacts the oldest human artifacts discovered in the Americas. Goodyear announced the results Wednesday in a news conference. They have not been published in a journal.

Currently, the oldest confirmed human artifacts in North America date from about 13,000 years ago. At least two sites in South America are claimed to be 30,000 years old or older, but researchers are not in agreement about whether those sites contain human tools or just rocks that have flaked and weathered until they look like tools.