records--Concluding remarks on the identity of the ancient and
present system of terrestrial changes.

_Origin of the doctrine of alternate periods of repose and
disorder._--It has been truly observed, that when we arrange the
fossiliferous formations in chronological order, they constitute a
broken and defective series of monuments: we pass without any
intermediate gradations, from systems of strata which are horizontal to
other systems which are highly inclined, from rocks of peculiar mineral
composition to others which have a character wholly distinct,--from one
assemblage of organic remains to another, in which frequently all the
species, and most of the genera, are different. These violations of
continuity are so common, as to constitute the rule rather than the
exception, and they have been considered by many geologists as
conclusive in favor of sudden revolutions in the inanimate and animate
world. According to the speculations of some writers, there have been in
the past history of the planet alternate periods of tranquillity and
convulsion, the former enduring for ages, and resembling that state of
things now experienced by man: the other brief, transient, and
paroxysmal, giving rise to new mountains, seas, and valleys,
annihilating one set of organic beings, and ushering in the creation of
another.

It will be the object of the present chapter to demonstrate, that these
theoretical views are not borne out by a fair interpretation of
geological monuments. It is true that in the solid framework of the
globe, we have a chronological chain of natural records, and that many
links in this chain are wanting; but a careful consideration of all the
phenomena will lead to the opinion that the series was originally
defective,--that it has been rendered still more so by time--that a
great part of what remains is inaccessible to man, and even of that
fraction which is accessible, nine-tenths are to this day unexplored.

_How the facts may be explained by assuming a uniform series of
changes._--The readiest way, perhaps, of persuading the reader that we
may dispense with great and sudden revolutions in the geological order
of events, is by showing him how a regular and uninterrupted series of
changes in the animate and inanimate world may give rise to such breaks
in the sequence, and such unconformability of stratified rocks, as are
usually thought to imply convulsions and catastrophes. It is scarcely
necessary to