laned down by the action of the sea, that no
trace of these vast dislocations is externally visible.

The Craven fault, for instance, extends for upwards of 30 miles, and
along this line the vertical displacement of the strata has varied
from 600 to 3000 feet. Professor Ramsay has published an account of
a downthrow in Anglesea of 2300 feet; and he informs me that he fully
believes there is one in Merionethshire of 12,000 feet; yet in these
cases there is nothing on the surface to show such prodigious movements;
the pile of rocks on the one or other side having been smoothly swept
away. The consideration of these facts impresses my mind almost in
the same manner as does the vain endeavour to grapple with the idea of
eternity.

I am tempted to give one other case, the well-known one of the
denudation of the Weald. Though it must be admitted that the denudation
of the Weald has been a mere trifle, in comparison with that which has
removed masses of our palaeozoic strata, in parts ten thousand feet
in thickness, as shown in Professor Ramsay's masterly memoir on this
subject. Yet it is an admirable lesson to stand on the North Downs and
to look at the distant South Downs; for, remembering that at no great
distance to the west the northern and southern escarpments meet and
close, one can safely picture to oneself the great dome of rocks which
must have covered up the Weald within so limited a period as since the
latter part of the Chalk formation. The distance from the northern to
the southern Downs is about 22 miles, and the thickness of the several
formations is on an average about 1100 feet, as I am informed by
Professor Ramsay. But if, as some geologists suppose, a range of
older rocks underlies the Weald, on the flanks of which the overlying
sedimentary deposits might have accumulated in thinner masses than
elsewhere, the above estimate would be erroneous; but this source of
doubt probably would not greatly affect the estimate as applied to the
western extremity of the district. If, then, we knew the rate at which
the sea commonly wears away a line of cliff of any given height, we
could measure the time requisite to have denuded the Weald. This, of
course, cannot be done; but we may, in order to form some crude notion
on the subject, assume that the sea would eat into cliffs 500 feet in
height at the rate of one inch in a century. This will at first appear
much too small an allowance; but it is the same as if we were t