structural:scholar_edition
Mound 72 Woodhenge

Early in the history of Cahokia the portion of the site containing Mounds 72 and 96 was the location of a "woodhenge", a ceremonial area with a 412 feet (126 m) in diameter circle of 48 upright wooden posts. Archaeologists date the placement of at least one of the posts to approximately 950 CE. Archaeological research has shown that four of the posts were at the cardinal locations of north, south, east and west, the eastern and western posts marking the position of the equinox sunrise and sunsets. Four other posts in the circle were shown to be at the summer solstice sunrise and sunset and the winter solstice sunrise and sunset positions. This setup is nearly identical to the diameter and post positions of Woodhenge III, one of five successive woodhenges built in another location at Cahokia, differing only in that Woodhenge III was 2 feet (0.61 m) smaller in diameter. Considering the size of the circle and the fact that the post holes themselves could be as much as 1 metre (3.3 ft) in diameter, this discrepancy is almost negligible. The placement of the two mounds at the location and the directions in which they are oriented correspond to several of the solstice marking posts. The post nearest the later elite burial of the "Birdman" is the location that marked the summer solstice sunrise at the times of the site's use. The early stages of the mounds were actually constructed around the posts, although at a later point the posts were removed. Besides their celestial marking functions, the woodhenges also carried religious and ritual meaning that is reflected in their stylized depiction as a Cross in Circle Motif on ceremonial beakers connected with black drink ceremonialism. One prominent example has markers added to the winter sunrise and sunset positions.