Archaeologists found western stemmed points including this one underneath Clovis points, making them a possible sign of the earliest migration into the Americas.

Center for the Study of the First Americans, Texas A&M University

This stone spear tip may have belonged to the first Americans

For 10 years, a team of archaeologists painstakingly excavated layer after layer of ancient stone tools near a Texas creek, looking for a sign of the first people to arrive in the Americas. Now, they have finally hit the jackpot: 11 spear points ranging from 13,500 to 15,500 years old. That places these stone tools among the oldest artifacts ever found in the Americas. What’s more, the uniquely shaped spear points lay buried beneath tools from the Clovis culture, dramatically demonstrating that the Clovis people were not the first to arrive in the Americas, as archaeologists long believed.

“This is the kind of research that’s going to push the peopling of the New World story forward,” says Todd Braje, an archaeologist at the California Academy of Sciences in San Francisco who was not involved in the work. The new paper hints at a signature style of tool made by these mysterious first Americans, which archaeologists may be able to use to trace their movement into North and South America.

The site where the tools were found—about 20 kilometers northwest of Austin—has year-round freshwater, making it, “an ideal place for people to be,” says Michael Waters, an archaeologist at Texas A&M University in College Station, who excavated there from 2006 to 2016. Apparently, prehistoric Native American communities agreed; stone tools in the area suggest people lived there for more than 10,000 years. Among the leavings are Clovis spear points used to hunt mammoths and other megafauna about 13,000 years ago.

Clovis points are unlike other spear tips because of their “flutes,” or vertical grooves chipped into each side of their bases. For many years, archaeologists thought the big game hunters who used them were the first to enter the Americas, walking from Alaska, through an ice-free corridor between the ice sheets of western Canada, and into the lower 48 about 13,500 years ago. But that idea started to collapse in 1997, when archaeologists confirmed that Monte Verde, a site in Chile, was at least 14,500 years old—meaning humans lived there before the ice-free corridor likely became a viable route.

Clovis points are characterized by grooves called “flutes” along their bases and are firmly dated to about 13,000 years ago.

Bill Whittaker/Wikimedia Commons (CC BY-SA 3.0)

As the tidy Clovis-first hypothesis unraveled, archaeologists were plunged into uncertainty. They didn’t know when or how the first Americans arrived. Worse still, they had no way of consistently identifying pre-Clovis stone tools, which—unlike the easy-to-recognize Clovis points—didn’t seem to have a unified style.

Now, Waters may have found such a style. Called “western stemmed points,” the new tools are generally smaller than Clovis points, lack the flutes, and taper toward a chunky stem. Waters’s team uncovered 11 western stemmed points in a layer of sediment about 15 centimeters below the earliest Clovis points at the site, meaning they are almost certainly older. But how much older?

The wet environment of the creek made radiocarbon dating impossible, so Waters used a technique called optically stimulated luminescence (OSL) dating, which measures when quartz grains in buried sediment were last exposed to sunlight. Waters’s measurements showed that sediment around the western stemmed points was 13,500 to 15,500 years old, likely making the tools at least that old, the team reports today in Science Advances. If their creators arrived in Texas that early, Waters says, the Pacific coast would have been their most probable route. They could have invented or adopted Clovis technology once they settled in the lower 48, or the two distinct styles could mean multiple migrations into the Americas took place.

Loren Davis, an archaeologist at Oregon State University in Corvallis, calls the work “really well done. … It’s breaking boundaries.” But because OSL dating has larger error bars than radiocarbon dating, using the latter technique on western stemmed points at another site—ideally also found beneath Clovis tools—“would nail it down.” Braje argues that the dates of more than 100 other tools at the site, and the fact that they were in precise chronological order, with the newest nearest the surface, makes a strong case for the accuracy of the older ages.

The findings could send archaeologists scrambling to find more western stemmed points in Texas and elsewhere in the Americas. Similar stemmed points have already turned up around the prehistoric Pacific rim, notes Braje, and some archaeologists were already wondering whether they could be the long-hoped-for signature of a coastal migration into the Americas. Waters’s discovery doesn’t close that case, Davis says, but “it’s very, very compelling.”