24 



THE SERI INDIANS 



[F.TH. ANN. 17 



The i)i-ecipitatioii ou the Souoraa proviuce is chiefly in the form of 

 rain; in the winter humid season snow falls frequently on the Sierra 

 Madre and rarely ou the outlying ranges; in both humid seasons (and 

 in humid spots at all seasons) dew forms in greater or less abuudauce. 

 Fog frequently gathers along the coast, especially during the winter and 

 in the midsummer wet season, and sometimes drifts inland for miles. The 

 mean annual precipitation may be estimated at 20 or 25 inches toward 

 the crest and half as much toward the base of the high sierra; thence 

 it diminishes coastward, probably to less than 2 inches; the mean for 

 the extensive plains forming the greater part of the province may be 

 estimated at 3 or 4 inches. The greater ])art of the ])recipitation is in 



out uf the Bureau. The tabulated records represent the obBervations of twenty years at Yuma and 

 ten years at Tucson. 



