Epigraph
“The inhabitants of the globe, like all the other parts of it, are subject to change. It is not only the individual that perishes, but whole species.
“A change in the animal kingdom seems to be a part of the order of Nature, and is visible in instances to which human power cannot have extended.”—Playfair, Illustrations of the Huttonian Theory, § 413.
Note
In thus separating the two works, however, I have retained in the “Principles” (book i.) the discussion of some matters which might fairly be regarded as common to both treatises; as for example, an historical sketch of the early progress of geology, followed by a series of preliminary essays to explain the facts and arguments which lead me to believe that the forces now operating upon and beneath the earth’s surface may be the same, both in kind and degree, as those which at remote epochs have worked out geological changes. (See Analysis of Contents of this work, p. ix.)
If I am asked whether the “Principles” or the “Manual” should be studied first, I feel much the same difficulty in answering the question as if a student should inquire whether he ought to take up first a treatise on Chemistry, or one on Natural Philosophy, subjects sufficiently distinct, yet inseparably connected. On the whole, while I have endeavored to make each of the two treatises, in their present form, quite independent of the other, I would recommend the reader to study first the modern changes of the earth and its inhabitants as they are discussed in the present volume, proceeding afterwards to the classification and interpretation of the monuments of more remote ages.
Charles Lyell.
11 Harley Street, London, May 24, 1853.
Note
historical sketch of the progress of geology, with a series of essays to show that the monuments of the ancient state of the earth and its inhabitants, which this science interprets, can only be understood by a previous acquaintance with terrestrial changes now in progress, both in the organic and inorganic worlds.