Some 15 millenniums ago, giant armadillos, dire wolves and Columbian mammoths roamed the prairies of Central Texas. And for the hunters who battled them, one rock quarry became a kind of Stone Age research lab for tools and weaponry.
Over the years archaeologists have peeled back the layers of a large prehistoric site along Buttermilk Creek between Florence and Salado where humans over thousands of years used an abundant supply of chert stone to fashion spears and cutting tools.
Now researchers from Texas A&M University, the University of Texas and Baylor University have announced the discovery of what may be some of the most significant findings yet from the area.
Based on lab results at Baylor, they say they have dated some of the oldest known spear points in North America, helping flesh out a story of the peopling of the Americas that is longer and more complicated than what you may have learned in school.
“We can’t say they’re the oldest points ever found, but so far it’s the best documented and vetted science that presents the oldest technology we know of right now,” said Baylor University geology Professor Steve Forman, a co-author of the study published Oct. 24 in the journal Science Advances.
“As you go farther back in the pages of human prehistory, there are fewer and fewer pages, just snippets. What science is is an evolving progress report. We’re trying to add more pages to a really intriguing story of how and why humans came to North America.”
Working at what is known as the Debra L. Friedkin site, archaeologists in 2015 dug through sediment layers representing thousands of years of archaic and Paleolithic cultures. They dug down to a layer dating to about 13,500 years ago and found the artifacts typical of that “Clovis” period, including a neatly fluted Clovis projectile point of the type that has been found across North America from the same period.
Then they dug deeper, one millimeter at a time, down 6 to 9 inches into floodplain clays believed to be between 13,500 and 15,500 years old. There they found about 100,000 stone artifacts, including 12 projectile points or point fragments that were definitely not Clovis.
These “lanceolate stemmed points” were more similar to pre-Clovis points found at other archaeological sites around North America, and they have been named the “Buttermilk Creek complex.”
At Baylor University, Forman’s crew dated the artifacts and surrounding soil based on a technique called optically stimulated luminescence. The verdict: The bottom of the layer where the points were found was up to 15,500 years old.
That date, and the whole notion of “pre-Clovis” humans in the Americas would have been an archaeological heresy just a few decades ago.
According to the long-reigning “Clovis First” theory, the first Americans crossed over the Bering Straits into Alaska and then into the heart of North America as the ice sheets retreated between 13,000 and 14,000 years ago.
“When I went through grad school (in the early 1980s), we were basically taught that the earliest evidence for humans in the Americas was Clovis,” said Mike Waters, who oversaw the Friedkin dig as director of the Center for the Study of the First Americans at Texas A&M. “There was a very elegant model of how people moved through the ice-free corridor. What I’ve witnessed over my time is the dismantling of the Clovis-First model.”
The theory developed cracks and has fallen apart with the discovery of demonstrably older sites in the Americas, including one older than 14,500 years in Monte Verde, Chile. Numerous other pre-Clovis sites have contributed more evidence of those early dates, including the Gault site adjacent to the Friedkin site. And cutting-edge genetic testing of ancient skeletons and modern Native Americans is confirming the theory of an older arrival, Waters said.
“That is transforming our field,” he said.
But if the ancestors of those chert-carvers at Buttermilk Creek did not follow the melting of the glaciers, how did they get here?
The Science Advances article suggests they came by boat, hugging the Pacific coastline all the way down to South America. But Waters said the emerging picture is complicated, with mobile populations diverging and reconverging over thousands of years, and sites like this one will help sort out that picture.
“This is a really exciting time to be in First Americans studies because things are changing so rapidly,” he said.
Waters said what is unique about the Friedkin site is the sheer number of artifacts — hundreds of thousands — and the meticulous work in documenting their antiquity.
“It’s clearly one of the oldest archaeological sites in North America,” he said. “At many of these sites that are older than Clovis, they might find a handful of artifacts. What this does is allow us to see a campsite of some of the first Americans.”
Meanwhile, archaeologists over the fence line at the Gault site are claiming even older dates for their stone tools, including projectile points. An archaeology team from Texas State University in July published an article, also in Science Advances, that dates the artifacts to between 16,000 and 20,000 years ago.
Waters, who once worked on the Gault site, acknowledged that the two sites are essentially continuous. He said it is possible that Gault has older artifacts, but the Friedkin site has better documentation of age.
“I think the key thing is you have two different teams working along the same drainage basin,” he said. “We excavated independently, we used different geologists, and we came to the same conclusion. That’s pretty powerful evidence to have that kind of reproducibility.”
Clark Wernecke, executive director of the Gault School of Archaeological Research, agreed that the two projects corroborate each other.
“It’s really good date from a really early time,” he said of the Friedkin findings. “The more of those we find, the more we have a pattern.”
Wernecke believes the chert along the Buttermilk Creek valley drew together far-flung bands of prehistoric people to camp, experiment with new tools and even find mates.
“It may be one of those places people got together and learned from each other,” he said. “The sheer quantity (of artifacts) argues that it’s one of those places.”
Waters agreed that the variety of tool techniques suggests the Buttermilk Creek area was a hotbed of experimentation.
There is evidence at the Gault site of regular use by Native Americans even into historical times. In modern times it continues to bring people of different tribes together, in the form of researchers from academic institutions often known as rivals.
Forman said UT-Austin, Texas A&M and Baylor have cooperated well on the Friedkin project.
“We have a really unique group of scientists who can really address the questions and problems of the peopling of North America,” he said of the trio of universities. “This is the Fertile Crescent of geology.”