NATURE FOR ITS OWN SAKE 
+ Sunset” 
valleys. 
Falley 
formation. 
Age of the 
valley, 
puts on her most gorgeous garments. Occa- 
sionally, in what are called the ‘‘sunset” val- 
leys—that is, valleys running east and west— 
there is some warmth of color, and in autumn, 
with the yellow foliage and the Indian-summer 
haze, there is often great display ; but during 
the hot months the predominant note is green, 
save where in the distant gulches and coolees 
the blues and purples assert themselves. 
There are two ways by which the mountain- 
valley may come into existence. The first is 
by the cutting-away process of torrents; the 
second is by depression. Oftentimes the heave 
of the fold that has lifted the mountain-peak 
skyward has allowed the valley to sink back 
and downward. A depression is thus formed 
which the wear of water immediately increases. 
Some valleys are even sunk lower than the sur- 
rounding country—so low as to make a hollow 
—and in time the waters flowing into them 
form the long, twisting monuntain-lake of 
which the Lake of Lucerne in Switzerland is 
an illustration. More often, however, the val- 
ley is elevated above its surrounding plains. 
From its walls one can always gain an approxi- 
mate idea of its age, as from the peaks one 
knows the age of the mountains. Abrupt sides 
