chalk beds were often
vertical, or cast into repeated folds, of which the escarpments were
mostly turned away from the Alps; but on the south side of the trench,
the Jurassic, Triassic, and Carboniferous beds, though much distorted,
showed a prevailing tendency to lean towards the Alps, and turn their
escarpments to the central chain.

295. Both these systems of mountains are intersected by transverse
valleys, owing their origin, in the first instance, to a series of
transverse curvilinear fractures, which affect the forms even of every
minor ridge, and produce its principal ravines and boldest rocks, even
where no distinctly excavated valleys exist. Thus, the Mont Vergi and
the Aiguilles of Salouvre are only fragmentary remains of a range of
horizontal beds, once continuous, but broken by this transverse system
of curvilinear cleavage, and worn or weathered into separate summits.

The means of this ultimate sculpture or weathering were lastly to be
considered.

* * * * *

296. III. _Sculpture._--The final reductions of mountainform are owing
either to disintegration, or to the action of water, in the condition of
rain, rivers, or ice, aided by frost and other circumstances of
temperature and atmosphere.

All important existing forms are owing to disintegration, or the action
of water. That of ice had been curiously over-rated. As an instrument of
sculpture, ice is much less powerful than water; the apparently
energetic effects of it being merely the exponents of disintegration. A
glacier did not produce its moraine, but sustained and exposed the
fragments which fell on its surface, pulverizing these by keeping them
in motion, but producing very unimportant effects on the rock below; the
roundings and striation produced by ice were superficial; while a
torrent penetrated into every angle and cranny, undermining and wearing
continually, and carrying stones, at the lowest estimate, six hundred
thousand times as fast as the glacier. Had the quantity of rain which
has fallen on Mont Blanc in the form of snow (and descended in the
ravines as ice) fallen as rain, and descended in torrents, the ravines
would have been much deeper than they are now, and the glacier may so
far be considered as exercising a protective influence. But its power of
carriage is unlimited, and when masses of earth or rock are once
loosened, the glacier carries them away, and exposes fresh surfaces.
Generally, the