These spherical grinding stones were slid or rolled across grinding surfaces to crush plants or seeds in food preparation. Stones that were rolled often maintain a pecked surface appearance. Sliding usually produces a smoothed, flattened surface on the bottom of the stone.
Milling stones are common artifacts on many sites throughout Georgia. These are often referred to as mortar and pestle or metate and mano stones (figure 1). The milling stone or basin or metate was used for grinding seeds, corn, or other vegetable products into flour for food. These stones appear more frequently at sites after the appearance of agriculture and pottery although they also occur on older sites and probably were used for processing wild plants for food (figure 2). Milling stones are normally large flattened rocks of considerable weight with a shallow (or rarely deep) basin-shaped depression in one or both sides (figure 3). They were used in conjunction with a hand-held stone or mano to grind seeds or grain. Both mortar and pestle stones are rarely found together as the large grinding stone was turned over and left behind when the camp was moved to avoid carrying the heavy stone. The pestle or mano, which required some shaping, would be taken along and a new grinding stone shaped at the new site.
The term "metate" is derived from sites in the Southwest and Mexico and refer to the corn grinding stone moved or rubbed back and forth in a washboard motion to grind the grain. (figure 4). This motion results in a trough-shaped grinding surface. Most milling stones found in Georgia have a oval or circular-shaped grinding surface on which the pestle or hand stone was moved in a circular or rotary motion.
Several examples of metate type milling stones have been recovered in recent years from Tennessee.
The "Bell" or "Pear-Shaped" pestle is one of the more common forms found in Georgia. These may have been used in a pounding motion or slid across the grinding surface to crush plants or seeds in food preparation.