98 LANDS OF THE ARID REGION OF THE UNITED STATES. 
at the crest of each abrupt descent there are many limestone ridges and 
crags. Between these ridges and crags that stand along the bordering 
crests, and the peaks that stand alone the meandering watershed, there are 
broad tables, some times covered with forests, sometimes only with grass. 
This is a third region of short summers and long winters, where the 
waters are collected to fertilize the valleys to the north and south. 
Away to the southward are the twin plateaus, Kast and West Tavaputs, 
severed by the Green River. These plateaus culminate at the Brown 
Cliffs, where bold escarpments are presented southward. 
Outlying the Brown Cliffs are the Book Cliffs. These, also, are 
escarpments of naked rock, with many salient and reéntrant angles and 
outlying buttes. .The beds of which they are composed are shales and 
sandstones of many shades of blue, gray, and buff. In the distance, and 
softly blended by atmospheric haze, the towering walls have an azure hue. 
Everywhere they are elaborately water carved, and the bold battlements 
above are buttressed with sculptured hills. In 1869, when the writer first 
saw this great escarpment, he gave it the name of the Azure Cliffs, but 
an earlier traveler, passing by another route across the country, had seen 
them in the distance, and, seizing another characteristic feature, had called 
them the Book Mountains. Gunnison saw, however, not a range of mount- 
ains, but the escarped edge of a plateau, and this escarpment we now call 
the Book Cliffs. Irom the Brown Cliffs northward these plateaus dip 
gently north to the Uinta-White Basin. From the very crest of the Brown 
Cliffs the drainage is northward. 
This is a fourth region of short summers and long winters, where the 
moisture is collected to fertilize adjacent lands ; but the altitude is not great 
enough nor the area large enough to accumulate a large supply of water, 
and the amount furnished by the Tavaputs Plateaus is comparatively small. 
Such are the lofty regions of Utah that furnish water to irrigate the 
lowlands. 
TIMBER. 
In these elevated districts is found all the timber of commercial value. 
This is well shown on the map. ‘The map also exhibits the fact that many 
portions of the elevated districts are devoid of timber, it having been 
