216 
NATURE FOR ITS OWN SAKE 
The old Ap- 
palachians, 
The older 
plains, 
Worn-down 
mountains. 
glacier grinds, and the ayalanche tears. All 
told, the wearing-down process is very effective. 
Perhaps, long before the Alps were bent upward, 
the Appalachians were towering in the air, the 
loftiest mountains on the globe ; but countless 
ages have given the elements the chance to wear 
them away, until to-day the ridge lines are al- 
most horizontal, and the once spectral peaks, 
that may have projected like dragons’ teeth, are 
no more. The torn and splintered look of the 
Alps and the Andes but prove their youth. 
The time will come when they will be worn 
away to low hills, and finally reduced to the 
common level. The flat plains, which we never 
think of as rock-based, are perhaps, in their 
foundations, the spots of earth that have re- 
mained undisturbed the longest of all. 
Many of the hill-ranges that lie about us 
to-day are merely very ancient mountains de- 
nuded of their mountain features by the con- 
stant wear of the elements. But all of them are 
not of thischaracter. Some of the hills were 
originally formed not by a fold but by a 
crack or split in the crust which has allowed 
one side to sink down and left the other side 
exposed to view, in abrupt cleavage, as it were. 
Such hills are not usually very high, and their 
