236 GEOLOGICAL SURVEY OF THE TERRITORIES. 



distant, tlie atmospliere is salubrious aud remarkably free from mias- 

 matic vapors aud imjiurities. Aud as we proceed southward, altliougli 

 there is a gradual increase in tlie average warmth, yet it is partially 

 compensated by strong breezes which stir the air during the warmer 

 season. In the summer the heat, it is true, is often somewhat intense, 

 especially in the valleys where the air is partially confined. But on the 

 higher grounds the breezes descending from the mountains render it 

 more pleasant. The air rarifled on the plains rises, while another por- 

 tion, cooled by the snows of the mountains, sweeps down the slopes and 

 brings with it a refreshing coolness. 



Snow generally begins to fall in October, and ceases in April, or about 

 the first of May, in the latitude of Denver ; but, as a matter of course, 

 beginning la-ter and ceasing earlier in the southern districts. 



Although it sometimes, though rarely, reaches a depth of twelve or 

 fourteen inches, yet it passes off almost as f apidly as it comes, seldom 

 remaining longer than twenty-four hours. Even in the valleys which 

 penetrate the first range of mountains in the northern section, this is 

 also the case. Some winters but little snow falls during the entire season. 

 As conclusive evidence of this statement, cattle are herded out during 

 the entire winter in all parts of the Territory, such a thing as prepara- 

 tion for winter-feeding being almost wholly unknown. And yet in the 

 spring they will come out in as good order as those of the States which 

 have been housed and fed day by day. The Mexican horses or bronchos 

 will also winter out during the season, like the cattle. 



The troublesome factor in the great problem of the development of 

 the agricultural capacity of the vast western plains is the supply of 

 water. Furnish this, and the fertile prairies and valleys east of the Mis- 

 sissippi will soon find a strong rival contending with them in the grain 

 marts of the world for precedence. Furnish this, and the " Great Amer- 

 ican Desert" of old geographers will soon become one mighty field of 

 flowing grain. Furnish this, and the few other minor impeding factors 

 will soon be eliminated. The streams rushing down from the mountains 

 slacken their course on the level plains where the great battle between 

 moisture and aridity begins. Is there any power in the human grasp 

 to assist nature in this struggle, aud turn the scale in her favor ? 



Before attempting to give a direct answer to this question, I will state 

 some facts connected with this matter, and then advance a theory, 

 which, if correct, is of great importance in developing the agricultural 

 capacity of this country. 



When we reached the Cache a la Poudre, at Laporte, I heard it re- 

 marked that this stream now, and for a few years past, has been sending 

 down a larger volume of water than it formerly did. I thought little of 

 the matter at the time and let it pass, simply noting the statement. 

 But when I reached the next stream in our journey south, the same thing 

 was repeated in regard to othei' streams in that section. And to confirm 

 the statement certain streams were pointed out, which, up to about 1862, 

 had been in the habit of drying up annually at certain points, which 

 since that time at these points have been constantly running. This 

 caused me aftervfards, during the whole length of our journey along the 

 eastern flanks of the mountains, to make this a special subject of inquiry. 



And somewhat to my surprise, I have found the same thing repeated 

 at almost every point as far south as Las Vegas, in New Mexico, and no 

 opposing testimony. Streams bearing down heavier volumes of water 

 than formerly ; others becoming constant runners which were formerly 

 in the habit of drying up ; springs bursting out at jDoints where formerly 

 there were none j acequias allowed to go to decay because they have 



