25 



the north side there is' a great deal of marshy land in these 

 basins ; but on the south the water, having to make about 

 looo feet more descent, runs off too rapidly to leave any 

 marsh. This circumstance, combined with the greater heat 

 of the southern exposure, makes many of the smaller streams 

 on that side run dry early in the season. The streams head- 

 ing in these mountains are characterized by main features 

 which are common to all. They are generally quite small, 

 and, taking their rise in the summit basins, they flow on the 

 north side, through narrow gorges with steep, heavily- 

 wooded slopes, until they emerge from the foot-hills in the 

 terraced plateaus which abut against the base of the range. 

 Above the plains their water is almost pure, from the fact of 

 its flowing only over sandstone. This quality, together 

 with its great coolness, makes the head-waters of these 

 streams the favorite abode of a very superior kind of moun- 

 tain trout. Below the upper limit of tree growth, which is 

 at about an altitude of 11,000 feet, the mountain ridges are 

 covered with a dense forest, very much interspersed with 

 small open meadows, with their grass often spreading itself 

 for a considerable distance into the timber. 



The valley bottoms are rich and pretty generally covered 

 with grass ; willow and cotton-wood trees grow near the 

 water, with groves of pine on the mountain slopes. Every- 

 where, even to the borders of the snow-banks almost at the 

 mountain heights, there is a luxuriant display of flowers, 

 and grasses thrive along the top of the ridges, above the limit 

 of tree growth and quite up to the summit of the range. 



The soil of the plateaus between the streams is almost ex- 

 clusively yellow marl, mingled with, and overlain in many 

 places by broad lines of drift from the mountains. It is quite 

 rich, and, under different climatic influences, fit to sustain 

 vegetation. At present only sage-brush, grease-wood, and 

 bunch-grass grow upon it. 



The whole of the mountain slopes, from the edge of the ter- 

 raced plateaus to an altitude of about 11,000 feet, are covered 

 with extensive forests of white and yellow pine, spruce, red 

 cedar, hemlock, and aspen. Nearly all of these woods were 

 of young growth ; thus giving evidence that extensive fires 

 have raged here at intervals over a long period of time. 



