58 BUREAU OP AMERICAN ETHNOLOGY [bull. 54 



them as to those now living in the region, though the boundaries of 

 the formations were probably at slightly lower elevations than now. 

 These things were part of the cliff-dwellers' environment as they are 

 part of the present environment. 



Though it seems highly probable that the disappearance of the 

 inhabitants from the region was due to progressive desiccation, it 

 need not be assumed that climatic change has been very great, and 

 surely it was not sudden. If the precipitation was once just sufficient 

 to make corn-growing on the mesas profitable, a decrease of only 

 two or tkree inches in the mean annual precipitation would make it 

 impossible without irrigation and at the same time would make 

 irrigation of the mesas impracticable. Such a decrease would cause 

 also the disappearance of springs which may have provided water 

 for the mesa-dwellers. 



It is probable that the culture exhibited by the archeologic evidence 

 of the region was developed under conditions almost if not quite as 

 rigorous as those of the present time. That this was Powell's opinion 

 is evident from the following quotation:^ 



The Pueblo peoples, ancient and modern, grew up under hard environment; 

 shadowed ever by the specters of thirst and famine, they were exceptionally impressed 

 by the potencies of pitiless nature and the impotency of their own puny power; and 

 like other desert peoples, seafarers, and risk -haunted folk generally, they developed 

 an elaborate system of ceremonies and symbols designed to placate the mysterious 

 powers. The ruins of the prehistoric settlements abound in relics of the ancient 

 tribesmen and their mystical cult; and the relics are largely interpre table through 

 researches in the modern pueblos. Occupying an arid region in which water is the 

 most precious of all commodities, the Pueblo peoples early acquired skill in the 

 manufacture of utensils adapted to the conservation of water, and eventually became 

 the potters par excellence of aboriginal America. 



The precipitation of the region has passed below the critical point 

 for corn-growing without irrigation, and so far as the archeologic 

 evidence shows, this was the chief crop of the ancient inhabitants, 

 but the slight change of cHmate which would make corn-growing on 

 a large scale impracticable might not produce much change in the 

 general appearance of the uncultivated vegetation. 



The phenomenon of succession in vegetation is universal. Geol- 

 ogy points to the fact that one type of vegetation is gradually replaced 

 by other types. These geologic successions are in many cases attrib- 

 uted to climatic changes. There are, however, successions of vege- 

 tation going on at the present time. But the changes which take 

 place from century to century are for the greater part due to changes 

 in soil, not climatic conditions. However, there seems to be some 

 botanical evidence, although meager, indicating changes in vegeta- 

 tion, due to climatic variation, within the last several thousand years. 



1 Powell, J. W., Seventeenth Rep. Bur. Amer. Ethn., p. Ixxii, 1898. 



