the borders of Wales are vertical in
the Mendip Hills in Somersetshire, where the overlying beds of the New
Red Sandstone are horizontal. Again, in the Wolds of Yorkshire the last
mentioned sandstone supports on its curved and inclined beds the
horizontal Chalk. The Chalk again is vertical on the flanks of the
Pyrenees, and the tertiary strata repose unconformably upon it.

_Consistency of local disturbances with general uniformity._--As almost
every country supplies illustrations of the same phenomena, they who
advocate the doctrine of alternate periods of disorder and repose may
appeal to the facts above described, as proving that every district has
been by turns convulsed by earthquakes and then respited for ages from
convulsions. But so it might with equal truth be affirmed that every
part of Europe has been visited alternately by winter and summer,
although it has always been winter and always summer in some part of the
planet, and neither of these seasons has ever reigned simultaneously
over the entire globe. They have been always shifting about from place
to place; but the vicissitudes which recur thus annually in a single
spot are never allowed to interfere with the invariable uniformity of
seasons throughout the whole planet.

So, in regard to subterranean movements, the theory of the perpetual
uniformity of the force which they exert on the earth's crust is quite
consistent with the admission of their alternate development and
suspension for indefinite periods within limited geographical areas.

UNIFORMITY OF CHANGE CONSIDERED, THIRDLY, IN REFERENCE TO SEDIMENTARY
DEPOSITION.

It now remains to speak of the laws governing the deposition of new
strata. If we survey the surface of the globe we immediately perceive
that it is divisible into areas of deposition and non-deposition, or, in
other words, at any given time there are spaces which are the
recipients, others which are not the recipients of sedimentary matter.
No new strata, for example, are thrown down on dry land, which remains
the same from year to year; whereas, in many parts of the bottom of seas
and lakes, mud, sand, and pebbles are annually spread out by rivers and
currents. There are also great masses of limestone growing in some seas,
or in mid-ocean, chiefly composed of corals and shells.

_No sediment deposited on dry land._--As to the dry land, so far from
being the receptacle of fresh accessions of matter, it is exposed almost
everywhe