GEiS'ERAL REPORT. 
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 lieavy 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 Green 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 upon 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 
