ngly aroused concerning igneous phenomena, Scrope continued his
travels and observations on the volcanic rocks of the peninsula of Italy
and its islands, and was thus led to a number of important conclusions
in theoretical geology, which he embodied in a work, published in 1825,
entitled _Considerations on Volcanos: the probable causes of their
phenomena, the laws which determine their march, the disposition of
their products, and their connexion with the present state and past
history of the globe; leading to the establishment of a New Theory of
the Earth_.

It is only right to point out that, in calling this book a _new_ 'Theory
of the Earth,' Scrope had no intention of comparing it with Hutton's
great work, with which he was at that time altogether unacquainted.
Nevertheless, his conclusions, though independently arrived at, were
almost identical with those of the great Scotch philosopher. But Scrope
made the same mistake as Hutton had done before him. He allowed his
theoretical conclusions to precede, instead of following upon an account
of the observations on which they were based. Scrope's book is certainly
one of the most original and suggestive contributions ever made to
geological science; but the very speculative character of a large
portion of the work led to the neglect of the really valuable hypotheses
and acute observations which it contained. In the preface, however, the
author gives a most striking and complete summary of the doctrine of
Evolution as opposed to Catastrophism, in the inorganic world, as will
be shown by the following extracts:--

Geology has for its business a knowledge of the processes which
are in continual or occasional operation within the limits of
our planet, and the application of these laws to explain the
appearances discovered by our Geognostical researches, so as
from these materials to deduce conclusions as to the past
history of the globe.

The surface of the globe exposes to the eye of the Geognost
abundant evidence of a variety of changes which appear to have
succeeded one another during an incalculable lapse of time.

These changes are chiefly,

I. Variations of level between different constituent parts of
the solid surface of the globe.

II. The destruction of former rocks, and their reproduction
under another form.

III. The production of rocks _de novo_ upon the earth's surface.

Geologists have us