This chronology is meant to furnish no more than a general idea of the time of existence of several of the better known Native American peoples of the southwestern U. S. and northern Mexico. While some times, archaeologists can speak with confidence about cultures and dates, more often, the development of chronologies for the cultures of the region is comparable to assembling three-dimensional jig saw puzzles from pieces which often mixed, jumbled, broken and missing. Widespread cultures evolved in different directions at different rates. External cultural influences had different degrees of impact on different cultures over time. Definitions of different cultures mean different things to different archaeologists.
Cultural boundaries are elusive.
Cultural chronology is a moving target.