94 NORTH AMERICA 



now thrown into broken ground, much eroded, with 

 ruined tables or ' mesas ' left standing, offers a large 

 variety of landscape. The flat tops of the dry mesas 

 have but a poor, semi-desert brush of leafless shrubs, 

 cacti, bushy composites, and scanty bunch-grass. 



The Llano Estacado and the transition zone of Texas 

 can be largely used for cattle-breeding ; part of Texas 

 is indeed a country of ranches, where cattle are left to 

 roam and find their own food over vast areas. Along the 

 rivers one comes across agricultural strips, but in the 

 arid sotol districts little can be done apart from the 

 slow cultivation of fibre-plants. Cotton is naturally 

 confined to alluvial tracts where irrigation is possible; 

 yet these tracts cover a sufficient surface to constitute 

 one of the main assets of Texas and north-east Mexico. 

 The water-melon and other fruits are also cultivated 

 extensively. 



The Grass Belt. Broadly speaking, west of the 100 

 meridian, up to the long Rocky chains, stretches a vast 

 region with a type of vegetation different from that 

 already described; it consists of flat or rolling plains, 

 rising westward to the foot of the mountains. The most 

 important feature of its climate is dryness, due to its 

 central position in the great body of land and its con- 

 sequent distance from the sources of moisture, the seas. 

 The rainfall hardly rises above a yearly average of 

 20 inches, and is most abundant at the growing season. 

 Summers are scorching and winters very hard in the 

 north and centre. 



The conditions of the vegetation throughout the great 

 grass-belt are very uniform. Over large territories the 

 endless table-like plains stretch, only furrowed by sunk 

 and invisible valleys. ' No trees, no shrubs, no tall 

 herbs ' ; but dull green close swards of buffalo-grass or 



