Prehistoric people carved images into exposed sections of dolomite above the Big River sometime between 500 and 2,000 years ago. Examples of this rock carving occur in many locations in the state, most of them in the central eastern portion where rock outcroppings are more common. The carvings were chipped, pecked, and ground into the stone, and they have been assigned to this time period based on symbols that occur only during that period, such as bilobed arrows and ceremonial maces, since archaeologists have no way to accurately date petroglyphs except through their content. At the time these carvings were made, American Indian people lived in this part of Missouri, hunting animals, gathering plants for food, and probably raising corn, beans, and squash at village sites along the Big River. Long before Europeans arrived, artists gathered at these stone outcroppings and created these images in the rock.