Since the 1930s, many archeologists have thought that the Clovis culture (prehistoric Paleo-Indian) was the first group of people to inhabit the Americas, where it expanded rapidly roughly 12,800 to 13,100 years ago. In more recent years, scientists have found increasing evidence of even earlier inhabitants. However, the notion of pre-Clovis culture in the Americas is highly controversial, as supporting evidence has been sparse and scattered.

New archaeological findings in central Texas might lessen some of that controversy. Michael Waters and his collaborators report in Science that they have found 15,528 artifacts from a pre-Clovis culture that dates back 13,200 to 15,500 years. Waters and his team found the large collection of artifacts under a layer of Clovis objects at the Debra L. Friedkin site near Buttermilk Creek. They dated the minerals in the artifacts using optically stimulated luminescence (OSL); they couldn’t use radiocarbon dating because the artifacts lacked organic material.

The pre-Clovis artifacts rested in soil that had high clay content. Further analysis of the magnetic properties and contents of the soil showed that there was little mixing. Thus, the artifacts would have laid in the soil undisturbed, without moving up or down from where they were buried.

Artifacts discovered by the archaeologists include tools and stone flaking residues that are small and lightweight, making them ideal for travel. While no organic residues were preserved with the artifacts, most of them showed wear and tear from both soft and hard materials, indicating that they had been in contact with organic materials. The design of the tools suggests that they could have been precursors to Clovis tools.

The large collection of pre-Clovis artifacts in Texas adds robust evidence to support those archaeologists who propose that there were inhabitants in the Americas before the Clovis culture. As the pre-Clovis people were present in North America well before the Clovis culture, they would have had time to spread across the Americas. Thus, they could be the ancestors of some later cultures.

Science, 2011. DOI: 10.1126/science.1201855