s supposed to be much the same as it is now--sediment
was quietly accumulated at the bottom of the sea, and animals and
plants flourished uninterruptedly in successive generations.
Each period of tranquillity, however, was believed to have been,
sooner or later, put an end to by a sudden and awful convulsion
of nature, ushering in a brief and paroxysmal period, in which
the great physical forces were unchained and permitted to spring
into a portentous activity. The forces of subterranean fire,
with their concomitant phenomena of earthquake and volcano, were
chiefly relied upon as the efficient causes of these periods of
spasm and revolution. Enormous elevations of portions of the
earth's crust were thus believed to be produced, accompanied by
corresponding and equally gigantic depressions of other portions.
In this way new ranges of mountains were produced, and previously
existing ranges levelled with the ground, seas were converted into
dry land, and continents buried beneath the ocean--catastrophe
following catastrophe, till the earth was rendered uninhabitable,
and its races of animals and plants were extinguished, never to
reappear in the same form. Finally, it was believed that this
feverish activity ultimately died out, and that the ancient peace
once more came to reign upon the earth. As the abnormal throes
and convulsions began to be relieved, the dry land and sea once
more resumed their relations of stability, the conditions of
life were once more established, and new races of animals and
plants sprang into existence, to last until the supervention
of another fever-fit.

Such is the past history of the globe, as sketched for us, in
alternating scenes of fruitful peace and revolutionary destruction,
by the earlier geologists. As before said, we cannot wonder at the
former general acceptance of Catastrophistic doctrines. Even in
the light of our present widely-increased knowledge, the series
of geological monuments remains a broken and imperfect one; nor
can we ever hope to fill up completely the numerous gaps with
which the geological record is defaced. Catastrophism was the
natural method of accounting for these gaps, and, as we shall see,
it possesses a basis of truth. At present, however, catastrophism
may be said to be nearly extinct, and its place is taken by the
modern doctrine of "Continuity" or "Uniformity"--a doctrine with
which the name of Lyell must ever remain imperishably associated.

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