PROVO, Utah, Aug. 23 (UPI) -- Ancient Americans added a new item to their daily menu about 10,000 years ago when the grinding stone used to make flour appeared, U.S. researchers say.
Brigham Young University scientists excavating one of the oldest known sites occupied by humans in what is now Utah found stone tools used to grind sage, salt bush and grass seeds into flour, a university release said Monday.
Before the appearance of grinding stones, evidence at the dig site shows the menu contained duck, beaver and turkey, with sheep becoming more common later on. And deer was a staple at all levels of the dig, BYU anthropologist Joel Janetski says.
The grinding stones would have meant more diet options -- probably not bread, but at least a mush or porridge made from milled and ground seeds.
"Ten thousand years ago, there was a change in the technology with grinding stones appearing for the first time," he said. "People started to use these tools to process small seeds into flour."
Janetski led a group of students using a National Science Foundation grant to "get to the bottom" of a site occupied on and off for the past 11,000 years, the university said.
Janetski and the students describe the tools in an article set for an upcoming issue of the journal Kiva.