This very large grinding stone was found on a site in southern Illinois, possibly in Calhoun County. It's one of the largest stone tools that has been found in this area. It was apparently used for multiple purposes. The long narrow groove on one side may have been used to grind axes. But a large shallow concave area on the other side may have been used for grinding food materials. The small circular concavities along the edges may have been used to crack nuts. This sandstone grinder weighs 76 lbs. and measures 20 3/8 inches (51.7cm) long, 15 inches (38.1cm) wide and 5 inches (12.7cm) thick.