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sculpture are waves and streams, frost and rain, and chemical 
decomposition. Every shower that falls exerts a wasting and 
weathering influence on rocks, soils, and all exposed surfaces, 
“There is no rock so hard but a little wave may beat admission in 
a thousand years ;” and so it is that every wave that beats along 
the troubled ocean’s shore, every ripple on the margin of the quiet 
mountain lake, every brook and stream and river as it leaps and 
rolls and sweeps along, slowly but surely alters or destroys the 
seemingly imperishable framework of our globe. Its contour is 
also considerably modified by the action of frost. Water passing 
through the numerous joints and fissures that exist in rocks of 
almost every kind at certain seasons of the year, becoming frozen, 
expands. It has then a tendency to rend and force apart the 
integral masses of the much-divided rocks, the consequence of 
which is, that when the thaw comes, these masses, having lost their 
cohesion, fall asunder, in many places producing those immense 
heaps of angular fragments at the foot of escarpments which, in 
our Lake District, go by the name of “‘screes.” Then again, water 
as it passes through the rocks, either by the joints or by the 
interstices of the component parts of the rock, dissolves and carries 
away portions of the lime, soda, potash, and magnesia that enter 
into their composition, thus promoting their disintegration. They 
crumble away, and are then in a condition to be borne to lower 
levels by either rain or rivers, or both—ultimately to be dropped 
by them into the sea. The mud and other sediments which are © 
borne down by, and which discolour our rivers and streams both 
during and for some time after a storm, may be mentioned as 
evidence of this particular kind of degrading action. At first sight 
we are not much impressed with its importance, but upon closer 
examination, we find that the mud which is annually borne down 
to the sea by rivers is something enormous. It has been shewn, 
for instance, that the united Ganges and Brahmapootra carry down 
to the bay of Bengal 40,000,000,000 cubic feet of solid matter 
every year. A better idea may be formed of that enormous 
quantity, when it is stated that at such a rate of deposition Enner- 
dale lake would be filled with sediment ina month. 
