eared enhanced by the
great contrast, in kind or intensity, of the causes referred to, and
those now in operation.

Never was there a dogma more calculated to foster indolence, and to
blunt the keen edge of curiosity, than this assumption of the
discordance between the ancient and existing causes of change. It
produced a state of mind unfavorable in the highest degree to the candid
reception of the evidence of those minute but incessant alterations
which every part of the earth's surface is undergoing, and by which the
condition of its living inhabitants is continually made to vary. The
student, instead of being encouraged with the hope of interpreting the
enigmas presented to him in the earth's structure,--instead of being
prompted to undertake laborious inquiries into the natural history of
the organic world, and the complicated effects of the igneous and
aqueous causes now in operation, was taught to despond from the first.
Geology, it was affirmed, could never rise to the rank of an exact
science,--the greater number of phenomena must forever remain
inexplicable, or only be partially elucidated by ingenious conjectures.
Even the mystery which invested the subject was said to constitute one
of its principal charms, affording, as it did, full scope to the fancy
to indulge in a boundless field of speculation.

The course directly opposed to this method of philosophizing consists in
an earnest and patient inquiry, how far geological appearances are
reconcilable with the effect of changes now in progress, or which may be
in progress in regions inaccessible to us, and of which the reality is
attested by volcanoes and subterranean movements. It also endeavors to
estimate the aggregate result of ordinary operations multiplied by time,
and cherishes a sanguine hope that the resources to be derived from
observation and experiment, or from the study of nature such as she now
is, are very far from-being exhausted. For this reason all theories are
rejected which involve the assumption of sudden and violent catastrophes
and revolutions of the whole earth, and its inhabitants,--theories which
are restrained by no reference to existing analogies, and in which a
desire is manifested to cut, rather than patiently to untie, the Gordian
knot.

We have now, at least, the advantage of knowing, from experience, that
an opposite method has always put geologists on the road that leads to
truth,--suggesting views which, although imperfect