effigy mound at English => English (The Britannica Concise) Of Explained:
Earthen mound in the form of a bird or animal (e.g, bear, deer, turtle, buffalo), found in the N central U.S., especially the Ohio River valley. Little is known of the effigy mounds except that most were burial sites. The culture that produced them dates from AD 300 to the mid-17th cent. See also Hopewell culture.