Description:
Walls surrounding three sites in northwest Yucatan, Mexico, were observed in aerial photography. The walls are thought to have been constructed during the Pure Florescent (Terminal Classic) period and to postdate the architectural complexes at the sites they surround. The photographs also show causeways connecting satellite communities with major centers; these are interpreted as Classic period attempts at boundary maintenance. The apparent trend toward increased severity of such activity through time is considered the result of demographic, social, and ecological factors.