| The late thirteenth century is selected as a focal point for investigating a lower Great Lakes paleoclimate because: (a) weather change was world-wide and corresponded to a well-marked excursion in solar radiation, (b) there is much evidence for widespread drought on the U.S. prairie and in the Southwest for the same period, (c) the sedentary Iroquoians were committed to agriculture by this time and their migrations can be traced in the distribution of their material remains, and (d) the thirteenth century provides a more valuable link to the ethnographic present than any previous comparable period of climatic change. The effects of similar recurrent climatic events on earlier cultural traditions of the Eastern Woodlands are discussed.;Several neglected research strategies for investigating Iroquoian prehistory are outlined. Conducted independently of contemporary archaeological theory and methodology, this study provides a chronological framework and a coherent explanation for the occurrence of certain signs left on the landscape and in the native languages.;Evidence for climatic change consists not only of movements of cultural traditions away from dry areas around lake Erie and lake Ontario, but also of current distributions of drought-susceptible plant species, and changes in pollen profiles from this region. The continental weather pattern responsible for extending the prairie peninsula along the lower Great Lakes plains is discussed. Maize-agriculture practices of Iroquoians and Anasazi are contrasted; and it is suggested that cold, dry westerlies would have affected the two cultures differently. Under relaxed or negative selection for drought resistance in the Northeast, strains of the highly evolved Northern Flint probably became drought-susceptible. Under relaxed selection for cold resistance, Chapalote and the floury Harinoso de Ocho varieties probably lapsed into susceptibility to chilling stress and to a short growing season at the higher altitudes of mesas and plateaus of the Southwest. |
