DALLAS (AP) — Anthropology researchers have found spearheads in Central Texas that the team’s leader says are the oldest hunting tools discovered so far in North America, according to a report published this week in the journal Science Advances.

The spear points, hewn of limestone, were found in 2015 at a dig near Buttermilk Creek, which is about 45 miles north of Austin, said Michael Waters, the Texas A&M University anthropologist who led the study and director of the university’s Center for the Study of First Americans.

Waters wrote in the report that analysis suggests the spearheads are between 13,500 and 15,500 years old, which is as many as 2,500 years older than projectile points found near Clovis, New Mexico, that many believed to be the oldest in North America.

The Texas artifacts came from what is known as the Debra L. Friedkin site, which was under excavation from 2006 to 2016. The earliest people in the area were hunter-gatherers who “probably moved from camp to camp over a year,” Waters said. They were likely attracted to the site by the year-round availability of drinking water and abundant chert on the surrounding slopes that was used for making stone tools. The region also had plenty of hunting and gathering in the surrounding Hill Country, Blackland Prairie and Coastal Plain, Waters said.

As for the spear points, they were not meant as combat weapons, Waters said.

“They were used for hunting. We saw evidence that they were hafted onto a spear (shaft), and there was clear evidence they were used for butchering,” he said. “They probably would have been used for hunting everything from mammoths and horses to deer.”

Given the age and shape of the recently found spear points, the people who used them likely arrived in the area from the Pacific coast as they circumvented the ice sheet that overlaid most of North America at the time, Waters said.

James Adovasio, director of archaeology at Harbor Branch Oceanographic Institute at Florida Atlantic University, wasn’t involved in the study. He said the spear points find was “certainly the oldest in Texas,” but questioned if they were the oldest discovered in North America.

Adovasio told The Associated Press that other sites “have produced items 1,500 or 2,000 years older than Clovis.” He argued the Clovis find was no longer the standard by which subsequent finds are judged, adding that the Texas find was “in the ballpark as some of the oldest finds (in North America). It may or may not be the oldest.”

Waters told the AP he was aware of other contenders for the oldest projectile points found in North America, but he contends there have been flaws in how the claims were substantiated. His findings are supported by the geological layer where his points were found, how they were dated, and the shape and style of the points, he said.

“Good stratigraphy, good dating, good artifacts,” Waters said.