110 NORTH AMERICA 



exclusively of the sage-brush, growing about three feet 

 high, in a loose formation which is never an obstacle to 

 the rider. With it may occur, according to the situation, 

 a few similar bushes, with whitish, small, strong-scented 

 leaves. This permanent vegetation is brightened, after 

 showers, by the sudden outburst of a flora of dwarf 

 annuals which disappears as quickly as it comes. Other 

 biennial and perennial herbs likewise wither and dis- 

 appear from the surface in July. 



The steep western slopes of the Wasatch Mountains are 

 destitute of trees, dry and naked. From this chain to the 

 Sierra Nevada, on the rocky slopes of all the ranges, is 

 found, at an elevation of 5,000 to 7,000 feet, a thin 

 sprinkling of western junipers and stunted, single-leaved 

 pines, some ten to fifteen feet in height, and of low, compact 

 habit. Only on the principal ranges, above 6,000 feet, 

 can the mountain mahogany be met, clinging to the 

 rocky ledges and on the dry inclines. The canons are 

 lined with a ragged brush of pines, firs, and junipers. 

 Where the ground water accumulates, however, the 

 desert is graced by delightful oases, marked by the 

 characteristic aspen, willow, poplar, and other leaf-shed- 

 ding trees of a northern type. 



As will be seen, the vegetation of the Great Basin 

 corresponds closely with that of the Algerian plateau in 

 north-west Africa ; it may also be compared with a large 

 portion of the plateau of Asia Minor. 



The Colorado plateau included between the Wasatch 

 and the Rocky chains extends south to the line of the 

 Mogollon Mountains, when it sinks abruptly along a much 

 broken bluff down to the sweltering desert of Gila. It is 

 a high tableland, cut up by deep and precipitous canons 

 into large flat-topped blocks or mesas, arid and treeless, 

 with a scanty plant-mantle of bunch-grass and grama- 



