WALTER HOUGH. 45 I 



These facts must be borne in mind in discussion of the environ- 

 ment of the southwest. As an example, it may be stated that 

 in the exploration of one ancient pueblo at Winslow, Arizona, 

 the bones of thirty-seven species of animals were taken from 

 the house refuse ; it is not probable at present that a naturalist 

 could collect five of these species from the environment. Wher- 

 ever the explorer's spade has been put in the ancient ruins, 

 facts of this character come to his notice, even if he has not 

 heard the story from the early settlers or Indian traditionists. 



There is no doubt that cycles of dry and wet seasons occur 

 in the southwest, but the periods have not been definitely ob- 

 served. Inferential data has been secured from exploration in 

 the ancient ruins that render it possible to explain the migra- 

 tions of early populations. 



The conditions of the environment briefly recapitulated are : 



1. A plateau of considerable elevation isolated geographi- 

 ally. 



2. Slight rainfall, locally distributed; absence of cloud 

 blanket; excessive light, radiation and evaporation; high 

 winds, dust storms; rarified air. 



3. Forested mountains, plains with xerophytic, hyhro- 

 phytic, and halophytic vegetation; plant colonies; desert 

 animals. 



Within this general enclave we have several sub-environments 

 which may be considered from the point of view of the avail- 

 ability for habitation by man . 



Sub -Environments : 



1. Prohibitive toman and in great degrees to animal and 

 vegetal life. 



2. Precarious except to man in low grade of culture, as 

 roving, hunting, and naturistic tribes. Animal and vegetal 

 life sufficient. 



3. Habitable by man acquainted with agriculture, but more 

 or less precarious. 



