44 BUREAU OF AMERICAN ETHNOLO(?Y [bull 54 



distant, the latter across the valley and somewhat more than 20 miles 

 distant. The mean annual precipitation at Santa Fe is 14.8 inches, 

 and at Espanola 10.5 inches. It seems probable that at the Rito de 

 los Frijoles the precipitation is approximately 14 inches, a supposition 

 finding support in the fact that the dominant plant formation 

 (pinon pine and cedar) on the lower part of the mesas is the same 

 as at Santa Fe. A short distance back from the rim of the Rio 

 Grande canyon on the mesas and in the gulches rock pine is found, 

 its presence indicating slightly greater precipitation. 



The aridity of the region is clearly reflected by the vegetation. 

 Such forms as the chandelier cactus {Opuntia arborescens) , Rocky 

 Mountain sage {Artemesia tridentata) , rabbit brush {CJirysotham- 

 nus sp.), yucca (Yucca haccata), evergreen oak (Quercus undulata), 

 and a predominance of composites tell one at a glance that the 

 region is arid. 



Figure 1 gives, for the purpose of comparison, the mean precipi- 

 tation by months at Santa Fe, Espanola, New York, and St. Louis. 

 The much greater precipitation at New York and St. Louis is at once 

 apparent. The New Mexico stations have the greatest monthly 

 amounts during July and August; the winters are dry. The annual 

 march of temperature at St. Louis, Santa Fe, and Espanola are given 

 in figure 2. The curves are similar, showing about the same distri- 

 bution of temperature throughout the year. In northern New 

 Mexico extremes of temperature, both diurnal and annual, are great. 

 In the area dealt with in this paper the prevailing direction of the 

 ^vind is southwest. 



Evidence of Change of Climate in Other Regions 



A recent change of climate in the Southwest having been frequently 

 suggested, some discussion of the general question seems appropriate 

 as bearing on the likelihood or unlikelihood of such changes here. 



Huntington,* who has made extensive investigations in the Old 

 World, gives much valuable information concerning the climate of 

 the historic past, knd is of the opinion that there have been such 

 changes. His data relate to such phenomena as changes in the levels 

 of lakes, length of rivers, distribution of plants and animals, ruins 

 and other evidence of man's former occupancy of regions now deserted 

 on account of unfavorable climatic conditions, and various traditiohs 

 and legends. The waters of the salt lake of Pangong, on the side of 

 the Himalaya mountains, seem to have receded within the period of 

 human history. In the Lop basin of Chinese Turkestan the amount 

 of vegetation has decreased within historic times and still shows signs 

 of progressive desiccation, due not to human agency but to climatic 



1 Huntington, Ellsworth, A Geologic and Physiographic Reconnaissance in Central Turkestan, Pub. 

 No. 26, Carnegie Inst, of Wash., 157-210, 1905; The Vale of Kasmir, in Bull. Amcr. Geoy. Soc, xxxvni, 

 657-82, 1900: The Pulse of Asia, New York, 1907. 



