of the
Alps was, at a still earlier period, occupied by a range of mountains no
less lofty than those of to-day. Thus then, though the present Alps are
comparatively speaking so recent, there are good grounds for the belief
that they were preceded by one or more earlier ranges, once as lofty as
they are now, but which were more or less completely levelled by the
action of air and water, just as is happening now to the present
mountain ranges.

Movements of elevation and subsidence are still going on in various
parts of the world. Scandinavia is rising in the north, and sinking at
the south. South America is rising on the west and sinking in the east,
rotating in fact on its axis, like some stupendous pendulum.

The crushing and folding of the strata to which mountain chains are due,
and of which the Alps afford such marvellous illustrations, necessarily
give rise to Earthquakes, and the slight shocks so frequent in parts of
Switzerland[44] appear to indicate that the forces which have raised the
Alps are not yet entirely spent, and that slow subterranean movements
are still in progress along the flanks of the mountains.

But if the mountain chains are due to compression, the present valleys
are mainly the result of denudation. As soon as a mountain range is once
raised, all nature seems to conspire against it. Sun and Frost, Heat
and Cold, Air and Water, Ice and Snow, every plant, from the Lichen to
the Oak, and every animal, from the Worm to Man himself, combine to
attack it. Water, however, is the most powerful agent of all. The autumn
rains saturate every pore and cranny; the water as it freezes cracks and
splits the hardest rocks; while the spring sun melts the snow and swells
the rivers, which in their turn carry off the debris to the plains.

Perhaps, however, it would after all be more correct to say that Nature,
like some great artist, carves the shapeless block into form, and endows
the rude mass with life and beauty.

"What more," said Hutton long ago, "is required to explain the
configuration of our mountains and valleys? Nothing but time. It is not
any part of the process that will be disputed; but, after allowing all
the parts, the whole will be denied; and for what? Only because we are
not disposed to allow that quantity of time which the absolution of so
much wasted mountain might require."

The tops of the Swiss mountains stand, and since their elevation have
probably always stood, above the range