AbstractDuring the late Quaternary the Willcox basin in SB Arizona was intermittently occupied by pluvial Lake Cochise. A radiocarbon-dated stratigraphic sequence indicates that high stands of the lake occurred from 13,750 to 13,400 B.P., once again during the early Holocene around or before 8900 B.P., and twice during the latter part of the middle Holocene. By the late Holocene, the basin was characterized by shallow and ephemeral playa lake stands.Ground stone artifacts once thought to be temporally associated with the last Pleistocene high stand of Lake Cochise are shown to come from nonlacustrine sediments and are younger than originally reported. These findings fail to confirm previous views that the Sulphur Spring stage of the Cochise Culture was contemporaneous with the Clovis Complex.Evidence of Middle Archaic occupation of the basin is sparse; however Late Archaic settlement structure is well documented and was characterized by residential base camps and associated specialized-activity loci. Resi...