rge is formed at that spot, not a sierra. Thus, in Fig. 18,
the beds are affected throughout their united body by the shock which
formed the ravine at _a_; but they are broken, one by one, into the
cliffs at _b_ and _c_. Sometimes one is tempted to think that they must
have been slipped back, one from off the other; but there is never any
appearance of friction having taken place on their exposed surfaces; in
the plurality of instances their continuance or rise from their roots in
waves (see Fig. 16 above) renders the thing utterly impossible; and in
the few instances which have been known of such action actually taking
place (which have always been on a small scale), the sliding bed has
been torn into a thousand fragments almost as soon as it began to
move.[51]

Sec. 23. And, finally, supposing a force found capable of breaking these
beds in the manner required, what force was it that carried the
fragments away? How were the gigantic fields of shattered marble
conveyed from the ledges which were to remain exposed? No signs of
violence are found on these ledges; what marks there are, the rain and
natural decay have softly traced through a long series of years. Those
very time-marks may have indeed effaced mere superficial appearances of
convulsion; but could they have effaced all evidence of the action of
such floods as would have been necessary to carry bodily away the whole
ruin of a block of marble leagues in length and breadth, and a quarter
of a mile thick? Ponder over the intense marvellousness of this. The bed
at _c_ (Fig. 18) must first be broken through the midst of it into a
sharp precipice, without at all disturbing it elsewhere; and then all of
it beyond _c_ is to be broken up, and carried perfectly away, without
disturbing or wearing down the face of the cliff at _c_.

And yet no trace of the means by which all this was effected is left.
The rock stands forth in its white and rugged mystery, as if its peak
had been born out of the blue sky. The strength that raised it, and the
sea that wrought upon it, have passed away, and left no sign; and we
have no words wherein to describe their departure, no thoughts to form
about their action, than those of the perpetual and unsatisfied
interrogation,--

"What ailed thee, O thou sea, that thou fleddest?
And ye mountains, that ye skipped like lambs?"

FOOTNOTES

[49] How far, is another question. The sand which the stream brings
from the bottom of o