ROBBm^^°^] CLIMATE AND EVIDENCE OF CLIMATIC CHANGES 55 



cause of the abandonment of the dwelHngs, then it is almost certain 

 that the mesa dwelhngs were first abandoned, the people possibly 

 crowding in the beginning down into the canyons, where conditions 

 remained more favorable, and overpopulating them. As crops may 

 still be raised in the limited bottom lands of the canyons, especially 

 in the few (as Frijoles canyon) containing small streams available 

 for irrigation, they would naturally be the last to lose their population. 

 If there has been progressive desiccation of the region it would be 

 fully adequate to account for the abandonment of these ruins by the 

 rather large population which ])robably once occupied them. Then, 

 inasmuch as the same condition is found over a very large area, 

 indicating that in the whole now arid region the aggregate population 

 must have been very great, the question would arise, where did they 

 go? It is not sufficient to say merely that they were driven out. 

 A general migration to some distant region where conditions are more 

 favorable would probably have left a well-defined trail in the tradi- 

 tions of the whole region. Numerous traditions of local migrations 

 are known, but all should be scanned with care before acceptance.' 

 It seems to the authors that a much more reasonable explanation of 

 the known phenomena is this: If the ramfall slowly decreased, 

 conditions must have become very gradually more severe. More 

 and more frequent droughts and accompanying starvation periods 

 would result, during which the weaker members of the tribe would 

 perish, not altogether from starvation, but from the reduction of 

 their powers of resistance to disease, cold, and other hardships 

 through w^ant of sufficient nourislmient. Thus the general physique 

 of the tribe would be preserved by the weeding out of the unfit instead 

 of weakening the physique of the tribe as a whole. As the severity of 

 such droughts increased it is probable that minor wars for the pos- 

 session of the small, better-watered tracts would occur, still further 

 reducing the various tribes and decreasing the aggregate population 

 of the region. Occasional minor epidemics would be apt to reduce 

 still further their numbers, especially if they occurred during periods 

 of drought. Thus it is reasonable to suppose that as a natural result 

 of desiccation the population decreased so gradually that the decline 

 could be discovered only by very accurate statistical records or by a 

 general comparison of the numbers living in the region at widely 

 separated periods. In this way the depopulation would progress 

 slowly by natural processes and therefore would not attract the atten- 

 tion of the inhabitants and would leave little impression in their 

 legends or traditions. The remnant of the population would grad- 

 ually move in small bands to situations favorable to agricultural 

 pursuits, thus becoming widely dispersed.- The foregoing changes 



1 Hewett, Edgar L., The Excavations at El Rito de los Frijoles in 1909, Papers School Amer. Archseol. 

 no. 10, pp. 670, 672, 1909. ' 



2 Hewett, Edgar L., Antiquities of the Jemez Plateau, Bull. Sg, Bur. Amer. Ethn., pp. 12-13. 



