Metates (IMAGE) University of Utah Caption Lisbeth Louderback, assistant professor of anthropology and curator of archaeology at the Natural History Museum of Utah, stands behind large stone metates, the grindstones on which ancient Native Americans processed their food. She discovered microscopic potato granules on 10,900-year-old stone tools in Escalante, Utah. Credit University of Utah Usage Restrictions Creative Commons with attribution License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.