A Late Woodland culture in the upper Mississippi valley characterized by low but very long burial mounds, built mainly between c 700-800 AD. The largest effigy mound is located in southern Ohio and is in the form of an uncoiling snake holding an egg-shaped object in its mouth. Most effigy mounds have been found in the shape of birds and others in the shape of animals. Bundled, flexed and cremated burials are common, with certain locations within the life-form mounds being preferred (e.g. the head, heart, and hips). Grave goods, if they occur at all, are very simple. Although it is known that most of the effigy mounds are burial sites, some are not, and their significance remains a mystery. The Effigy Mound culture has been dated from AD 300 to the mid-1600s.