: Archeologists have discovered thousands of stone tools in Texas that are over 15,000 years old. The find is important because it is over 2,000 years older than the so-called Clovis culture, which had previously thought to be the first human culture in North America. As Texas A&M University anthropologist Michael Waters says, "This is almost like a baseball bat to the side of the head of the archaeological community to wake up and say, 'hey, there are pre-Clovis people here, that we have to stop quibbling and we need to develop a new model for peopling of the Americas'." How the Heck:

What's the News

At a site on Buttermilk Creek in central Texas, Archeologists discovered 15,528 items, ranging from chert flakes to blades and chisels.

The first indication that the tools were older than anything previous seen on North America came from their stratigraphic horizon: The excavated layer was underneath a layer of classic Clovis tools. (The sediments showed no indication of mixing after the tools were dropped.)

The most conclusive evidence came from a dating technique called optically stimulated luminescence (OSL) dating, which indicates how long minerals have been underground. Over 60 OSL dates revealed the tools to be about 15,500 years old, much older than the up-to-13,500-year-old Clovis culture.

What's the Context:

Not So Fast:

Some anthropologists say that the "Clovis first" theory went out of style years ago, and that this study only puts the nail in the Clovis coffin.

Others are skeptical about this present finding, noting that OSL dating is less reliable than radiocarbon dating and that the site's deposits are "potentially problematic" because they're located on an old floodplain and could have been transported by water.

The Future Holds: Now it's time for archeologists to rethink the North American narrative of migration: How did humans first populate the continent? As James Adovasio, the executive director of the Mercyhurst Archaeological Institute, told NPR, "Everything we're learning now, from genetics, from linguistic data, from geological data, from archaeological data, suggests that the peopling process is infinitely more complicated than we might have imagined 50 years ago, or even 20 years ago." Reference: The Buttermilk Creek Complex and the Origins of Clovis at the Debra L. Friedkin Site, Texas. By Michael R. Waters et al. DOI: 10.1126/science.331.6024.1512

Image: Courtesy of Michael R. Waters