and reproduction of rocks were always in progress, proceeding with
the utmost uniformity, the learned Carmelite represented the repairs of
mountains by elevation from below to be effected by an equally constant
and synchronous operation. Neither of these theories, considered singly,
satisfies all the conditions of the great problem, which a geologist,
who rejects cosmological causes, is called upon to solve; but they
probably contain together the germs of a perfect system. There can be no
doubt, that periods of disturbance and repose have followed each other
in succession in every region of the globe; but it may be equally true,
that the energy of the subterranean movements has been always uniform as
regards the _whole earth_. The force of earthquakes may for a cycle of
years have been invariably confined, as it is now, to large but
determinate spaces, and may then have gradually shifted its position, so
that another region, which had for ages been at rest, became in its turn
the grand theatre of action.

_Playfair's illustrations of Hutton._--The explanation proposed by
Hutton, and by Playfair, the illustrator of his theory, respecting the
origin of valleys and of alluvial accumulations, was also very
imperfect. They ascribed none of the inequalities of the earth's surface
to movements which accompanied the upheaving of the land, imagining that
valleys in general were formed in the course of ages by the rivers now
flowing in them; while they seem not to have reflected on the excavating
and transporting power which the waves of the ocean might exert on land
during its emergence.

Although Hutton's knowledge of mineralogy and chemistry was
considerable, he possessed but little information concerning organic
remains; they merely served him, as they did Werner, to characterize
certain strata, and to prove their marine origin. The theory of former
revolutions in organic life was not yet fully recognized; and without
this class of proofs in support of the antiquity of the globe, the
indefinite periods demanded by the Huttonian hypothesis appeared
visionary to many; and some, who deemed the doctrine inconsistent with
revealed truths, indulged very uncharitable suspicions of the motives of
its author. They accused him of a deliberate design of reviving the
heathen dogma of an "eternal succession," and of denying that this world
ever had a beginning. Playfair, in the biography of his friend, has the
following comment on this