The Southeastern United States is not a sharply bounded region. Climate and cultural pattern alike shift by small degrees from the climax of the relatively densely populated, complex societies of the semitropical Gulf coastal belt, northward to the more scattered villages of the colder states. The Southeast would have been a desirable habitat for humans during late Pleistocene glaciations. Early Archaic begins in the Southeast at the close of the Pleistocene about ten thousand years ago. Triangular dart points fastened to shafts by binding secured around deeply indented bases are diagnostic of the Eastern Early Archaic. In the Eastern Woodlands, as in the contemporary American Southwest, eight-rowed maize seems to have been a critical factor in the development of town-based societies along the regions' northern frontiers. Mississippian is the last prehistoric period in the Eastern Woodlands. Mississippian seems to have crystallized out of the Lower Mississippi Valley and Gulf Coast agricultural societies flourishing throughout the decline of Hopewell.