8 BUREAU OF AMERICAN ETHNOLOGY [blll. 35 



high ridges and dash through canyons or water the fertile acres of 

 the upper valleys. The streams grow larger and the canyons grow 

 wider in the middle courses of the rivers, till in the lower reaches 

 great valleys open out, in which an ancient population, like that of 

 the lower Gila and Salt, flourished by grace of the moisture condensed 

 on the mountains to the northeast. 



Above the G,000-foot contour the mountains are clothed with a 

 dense growth of pine, constituting part of the greatest. virgin forest 

 remaining in the United States. The forest on the higher plateau 

 is open and interspersed with groves of live oak and aspen, forming 

 beautiful parks. Descending from the " rim," one traverses the 

 habitats of plants ranging from the Boreal to the lower Austral 

 zone, so that in following the canyon of Blue river, Arizona, one 

 passes from the pine to the cactus in less than GO miles, having 

 encountered numerous vegetal forms, each appearing at its limit of 

 elevation. 



In accord with the prevalence of vegetal life, there is on this slope 

 abundant and diversified animal life, and here may be found the 

 larger and smaller mammals and birds, and other animals character- 

 istic of the Austral zones, which on their western edges approach 

 the Tropical life zone of the lower Colorado and Salt rivers. 



The climate is generally agreeable, depending upon the elevation, 

 growing cooler as one ascends toward the " rim.' 1 On the whole, 

 this great area is suitable for human habitation, especially in the 

 upper Austral zone, which, with its ample water and vegetation, 

 would afford support for agricultural and hunting tribes. This is 

 shown by the numerous and widespread areas in the river valleys 

 which man has cultivated and by the evidences of his occupancy of 

 caves, cliff-dwellings, and pueblos, that render this section of the 

 United States of especial archeologic interest. 



The geographical features of the region are marked by a number 

 of enclaves, producing isolation and corresponding development of 

 subcultures within the general, comparativel} 7 uniform pueblo cul- 

 ture. The movement of population was along the narrow valleys 

 of streams, shut off from contact with other tribes by high mountain 

 masses. That the .early tribes were not disturbed is shown by many 

 evidences, notably the absence of defensive works or defensive posi- 

 tions of pueblos and the dearth of implements of war. 



HISTORY 



The region is also particularly interesting because the earliest Euro- 

 pean expedition into the southwestern part of the present domain of 

 the United States, led by Marcos of Niza, crossed this uninhabited and 

 inhospitable territory in 1539. In the next year Francisco Vasquez 



