(CNN) It's a discovery that could rewrite the story of southeastern United States.

Stone tools and mastodon bones found at the bottom of a Florida river point to humans living in the region 14,550 years ago. That's more than 1,500 years earlier than previously believed, scientists say.

"It's pretty exciting. We thought we knew the answers to how and when we got here, but now the story is changing."

The discovery on the Aucilla River was reported Friday by the journal Science Advances.

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