Platform Mounds of the Arizona Desert: An Experiment in Organizational Complexity

Platform mounds were built by the prehistoric Salado and Hohokam people of southern Arizona from the 13th through the 15th century A.O., the Classic period. They are basically artificial, flat-topped hills on which the ruling families of the day built their homes. Additional residences and storage rooms were built around the base of a mound, and the whole was enclosed within a compound wall. Each mound was the administrative, ceremonial, and economic center for a small-scale political system, or polity, whose settlements were scattered over 5 to 25 square miles. At their maximum extent there were probably about 100 of these little political systems scattered across the Sonoran Desert of Arizona.

Platform mounds appeared throughout Tonto Basin during a very short time span around A.D. 1280; five different platform mounds were constructed within the Livingston area alone. Many of the mounds were built by removing the roofs from the rooms of preexisting buildings, and filling the rooms with cobbles and dirt to create the platform.

The archaeology of the Livingston area has provided new insights into the phenomena of platform mounds. It has shown in surprising detail how a centralized, powerful leadership emerged through a process of gradual amalgamation. The importance of family leaders in the early Roosevelt phase was replaced in late late Roosevelt by a smaller number or important lineage leaders, and in the Gila phase by the authority of a single clan chief. The lower-level leaders did not disappear from the society; every family still had a family head, and every lineage still had their respected elders. But a new level of hierarchy developed, with leaders who assumed greater power and authority.

The amalgamation process in Livingston also exhibited an interesting progression from ceremonial authority toward economic authority. Public buildings at the beginning of the Roosevelt phase were devoted completely to large communal meeting rooms. By the end of the Gila phase, the platform mounds functioned primarily as elite residences and as storehouses for the society's wealth.