166 THE FUTURE OF ARID LANDS 
Geochronological Approach 
Antevs has done much work in determining the paleoclimatic 
story in the Southwest. His researches, based on geologic-climatic 
observation and study, are the basis for much of our interpretation 
of paleoclimate during the pre-Christian eras. Much of his work 
was conducted in conjunction with archaeological problems con- 
cerning ‘‘early man”’ discoveries in the area. Thus we have some 
spotty knowledge of climate and man for the last 12,000 years, 
although there are large gaps in this period for which we have no 
information. The data derived by Antevs are based on the rise and 
fall of lake levels, arroyo cutting and filling, the formation of 
caliche, the deposition of laminated beds, and other geologic and 
climatic features. 
The detailed study of archaeological chronology in the Southwest 
is now being started at the University of Arizona through the use 
of tree-ring dating and carbon-14 analysis. Many dates on various 
stratigraphical correlations will be necessary for minute analysis 
of this problem. 
Identification of the flora and fauna found associated with such 
archaeological sites will also be one of the major problems in this 
study. Studies in palynology have been recently started for this 
area, and preliminary runs indicate far better results than had 
been expected. These runs indicate that ‘‘caves may be to the 
arid regions what peat bogs are to the glaciated areas.” In caves 
which have been occupied by man, and many have been say for 
10,000 years, we have found not only wind-blown pollen but also 
pollen from plants which were insect pollinated and which may 
have been brought in by man for preparation of food. Other caves, 
not occupied by man, give good wind-blown series plus grains from 
plants which were probably carried in by animals. The open clay 
deposits, or cienegas, in the valley bottoms also yield pollen 
although not as much as do the caves. 
It is hoped that the pollen spectra associated with archaeological 
sites in which specific identification of plant and animal remains 
can be made will give a more accurate understanding of detailed 
climatic indices for such things as rainfall and temperatures. The 
dating of these sites would enable us to locate them along the time 
