UNDERGROUND WATER 1438 
column ; and in some places, notably in Luray, there 
is a wonderful and weird beauty in the variety of 
these alabaster forms. 
Landslips. —On the sides of steeply sloping hills, 
and particularly in precipitous mountains, masses of 
earth are often dislodged, and a landslide or avalanche 
is formed. ‘The name applied 
varies with the amount of the 
displacement, the avalanche 
being the most violent. In 
many cases it is underground 
water which starts the soil. 
When snow and frost melt, or 
when a heavy rain soaks the 
ground, masses of earth are 
caused to slip. 
Perhaps the weight of a 
a heavy covering of snow, or a 
Stalactites, stalagmites, and col- strong win d blowing against 
umns in Luray Cavern. (Copy- 
righted, 1882, by C- H. James, +he trees, may give the im- 
Philadelphia, Penn.) 
petus; or the slide may have 
its origin merely in the slippery condition of the soil, 
which is so ready to move that it starts by the mere 
action of gravity, without a perceptible cause, just as 
the face of a cliff may at any time break away and 
fall, when the right stage has been reached. 
A frequent cause for landslips and avalanches is the 
