Nine centuries ago, small settlements of the Cahokia Mississippian culture from the south appeared along the Illinois River valley here. These people transformed the local Woodland culture, as shown by shell-tempered pottery, rectangular houses, and ceremonial practices that included extended burials, platform mounds, and several types of ceremonial buildings. Within a few generations, the influence of this cultural phase, called Eveland, led to the development of a large, stable population with a complex society now known as Spoon River Mississippian. Although many Eveland phase sites consisted of single homesteads or small groups of houses, the Eveland Site itself apparently served as a ceremonial center for a number of these habitation sites. Associated with this center, on the bluff above, was a rectangular, flat-topped mound around which several low burial mounds were placed, and the flat-topped mound was probably used for mortuary ceremonies.