15,000-year-old campsite in Texas challenges conventional story of American settlement

15,000 years ago, humans camped in a lush Texas valley, leaving thousands of artifacts behind, from tools to face paint. This could be definitive proof that ancient people arrived in America by boat, not by walking the Bering Strait.

Anthropologist Michael Waters and colleagues announced their findings today, detailing the almost 16,000 artifacts they found near Buttermilk Creek, outside the Austin area. Their discovery will change everything you thought you knew about how people arrived in the Americas.

Meet the Buttermilk Creek people

What's remarkable is that this places human occupation of America over 2,000 years earlier than previously believed. And apparently, these early settlers loved the Buttermilk Creek area - there is evidence that it's been a popular campsite for thousands of years. As Waters put it yesterday at a press conference:

It seemed that the Buttermilk Creek area was a place that people came back to continually. It's as if when that site was discovered or that valley was found, that people kept coming back for over 15,000 years.

15,000-year-old campsite in Texas challenges conventional story of American settlement

The artifacts Waters found, which he and his colleagues call the Buttermilk complex, were mostly made from white chert, a popular stone for tools because like onyx it can be flaked into very sharp knife-edges. Yesterday at a press conference, Waters explained that the Buttermilk toolset included weapons, plus tools for preparing hide and shaping bone and wood. From that, we can extrapolate that these people had a developed textile culture (including pigments for decorating their clothing). They also used many materials, like wood and bone, for everything from tools to jewelry. Their toolkit was also small enough to be packed up and carried, which confirms that the campers were probably nomadic, returning to Buttermilk Creek on a seasonal basis.

The researchers used a new dating technique called optically stimulated luminescence (OSL) to date the sands around the artifacts, and are certain that they date to roughly 15,000 years ago.

How did they get to America?

Many anthropologists believe that the first people in the Americas came over the Bering Strait roughly 13,000 years ago, at a time when there was a breech in the ice sheets that would have permitted passage. According to this account, these people came from Northern Asia and brought "Clovis technology" with them, which included sophisticated arrowheads among other things. Now it seems that people came much earlier, and developed the Clovis technology once they arrived in the regions we now call North and South America. Waters told reporters:

This is almost like a baseball bat to the side of the head to the archeological community to wake up and say, hey, there are pre-Clovis people here . . . and we need to develop a new model for peopling of the Americas.

15,000-year-old campsite in Texas challenges conventional story of American settlement

So what would this new model be? Most likely, North Asian people came to the Americas in boats, just the way their ancestors got to Australia 50,000 years ago. Waters said:

15,500 years ago, the ice-free corridor was closed [in the Bering Strait]. The two ice sheets were merged. So this lends indirect credence to the idea that people came along the coast and entered the Americas. If that's the case, then perhaps people came up the Columbia River [in Washington], because that would have been the first major entry into the continent. And we should start looking for early sites there.

Indeed, there is a site in Oregon with just a few artifacts that could be part of the Buttermilk complex.

Most likely these people would have traveled down the coast, eventually reaching as far as southern Chile, where the famous Monte Verde campsite contains human artifacts believed to be nearly 15,000 years old too.

Waters says soon scientists will sequence DNA from skeletons found in these Buttermilk-era sites, which should help them figure out how humans arrived in the Americas and where they came from. But he was willing to speculate about what it would have been like for these early settlers as they explored:

[I'm not saying] 1,000 people just marched in all at the same time. They probably came in dribs and drabs, you know, one group and then another group of maybe 50, another group of 100, another group of maybe 80 coming down, but all coming from some sort of common genetic ancestor . . . Prior to this, everybody was saying, well, they were coming along the coast and they were paddling as fast as they could to get down to the southern tip of South America. I think people take a little bit of time as they were coming along the coast, because they're going to find the Columbia River. They're going to find San Francisco Bay. They're going to find Santa Barbara and San Diego. That's where I would have stopped; I'm from San Diego.

This discovery confirms beyond a doubt that people arrived in America before 15,000 years ago, which in turn strikes a major blow against the Bering Strait theory of migration. It also means that one of the most sophisticated tool sets of the pre-historical world, the Clovis complex, was developed in the Americas by people whose children founded the cities and industries that dominated North and South America for thousands of years before Europeans arrived.

Read the full scientific article at Science.