dded_ structure in all the
instances of mountain form given in the preceding chapter; and must have
asked himself, Why are mountains always built in this masonry-like way,
rather than in compact masses? Now, it is true that according to present
geological theories, the bedded structure was a necessary consequence of
the mode in which the materials were accumulated; but it is not less
true that this bedded structure is now the principal means of securing
the stability of the mass, and is to be regarded as a beneficent
appointment, with such special view. That structure compels each
mountain to assume the safest contour of which under the given
circumstances of upheaval it is capable. If it were all composed of an
amorphous mass of stone as at A, Fig. 19, a crack beginning from the
top, as at _x_ in A, might gradually extend downwards in the direction
_x y_ in B, until the whole mass, indicated by the shade, separated
itself and fell. But when the whole mountain is arranged in beds, as at
C, the crack beginning at the top stops in the uppermost bed, or, if it
extends to the next, it will be in a different place, and the detached
blocks, marked by the shaded portions, are of course still as secure in
their positions as before the crack took place. If, indeed, the beds
sloped towards the precipice, as at D, the danger would be greater; but
if the reader looks to any of the examples of mountain form hitherto
given, he will find that the universal tendency of the modes of
elevation is to cause the beds to slope _away_ from the precipice, and
to build the whole mountain in the form C, which affords the utmost
possible degree of security. Nearly all the mountains which rise
immediately above thickly peopled districts, though they may appear to
be thrown into isolated peaks, are in reality nothing more than flattish
ranks of rock, terminated by walls of cliff, of this perfectly safe
kind; and it will be part of our task in the succeeding chapter to
examine at some length the modes in which sublime and threatening forms
are almost deceptively assumed by arrangements of mountain which are in
themselves thus simple and secure.

Sec. 3. It, however, fell within the purpose of the Great Builder to give,
in the highest peaks of mountains, examples of form more strange and
majestic than any which could be attained by structures so beneficently
adapted to the welfare of the human race. And the admission of other
modes of elevation, more