GENEEAL EEPORT. Xvii 



times cleft like a gateway to the valley level, with perpendicular mountain 

 walls on each side, but usually opening out at some part of their course into 

 meadow-like basins or "parks." The prevalent western winds deposit their 

 moisture, which they have gathered in the traverse of the Basin, in abundant 

 snows in winter and at other seasons in frequent and occasionally heavy rains. 

 The upper canons and mountain slopes are to some extent timbered, much 

 more generally so than in any of the ranges westward, and the naked peaks 

 above have a truly alpine vegetation. The Uintas, which connect immedi- 

 ately with the Wahsatch and extend eastward on the line of the 41st parallel 

 for' a distance of 150 miles to Green River, where they meet the outspurs 

 of the Rocky Mountains of Colorado, have more of the character of those 

 mountains, with broad open canons and extended lines of foothills, the peaks 

 overtopping those of the Wahsatch, glacier-scored and polished at the north- 

 ern base, but the declivity upon the opposite side stretching southward beyond 

 the limits of vision in a high plateau broken only by the deeply-worn channels 

 of numerous rapid streams, tributaries of the Uinta and Grreen Rivers. 



Meteorological Notes. The climate of the Basin in this latitude 

 may be said in general to be characterized by a very dry atmosphere and 

 consequent small amount of rain and snow, especially in the valleys, and by 

 a cold winter and correspondingly hot summer, the greatest extremes of each 

 kind occurring at the lower altitudes of the western depression. The data, 

 however, for definite general statements are scanty. No measurement of the 

 rainfall at any point in the Great Basin has. been reported. It varies greatly 

 with the altitude and is probably considerably more jupon the eastern slope 

 of the mountains than upon the western. Though any statement of the 

 average annual amount must be largely conjectural, yet it may be roughly 

 estimated at eighteen inches, of which one-half may be considered as falling 

 between the months of April and November inclusive. In the warmer 

 months the rains are always limited and of short duration, centering about 

 the mountain peaks and occasionally very severe. DeWs and frosts are almost 

 wholly unknown. 



Field-notes taken in Western Nevada in 1867 show that from the last 

 week in July to August 31st only ten days were nearly cloudless, while on 

 thirteen days there was rain, though in most cases only in sprinkles or light 

 showers at the place of observation. In September, ten days again were 

 wholly without clouds though exceedingly hazy, as was also the case in August, 

 iii 



