DIRECTOR-GENERAL OF THE GEOLOGICAL SURVEY OF THE UNITED KINGDOM, AND DIRECTOR OF THE MUSEUM OF PRACTICAL GEOLOGY, JERMYN STREET, MINERALOGY IN THE UNIVERSITY OF EDINBURGH ILLUSTRATED WITH WOODCUTS LONDON MACMILLAN AND CO. 1886 [The Right of Translation and Reproduction is reserved.] PREFACE. THE present volume completes a series of educational works on Physical Geography and Geology, projected by me many years ago. In the Primers, published in 1873, the most elementary facts and principles were presented in such a way as I thought most likely to attract the learner, by stimulating at once his faculties of observation and reflection. The continued sale of large editions of these little books in this country and in America, and the translation of them into most European languages, leads me to believe that the practical methods of instruction adopted in them have been found useful. They were followed in 1877 by my Class-Book of Physical Geography, in which, upon as far as possible the same line of treatment, the subject was developed with greater breadth and fulness. This volume was meant to be immediately succeeded by a corresponding one on Geology, but pressure of other engagements has delayed till now the completion of this plan. So many introductory works on Geology have been written that some apology or explanation seems required from an author who adds to their number. Experience of the practical work of teaching science long ago convinced me that what the young learner primarily needs is a class-book which will awaken his curiosity and interest. There should be enough of detail to enable him to understand how conclusions are arrived at. All through its 404279 chapters he should see how observation, generalisation, and induction go hand in hand in the progress of scientific research. But it should not be overloaded with technical details which, though of the highest importance, cannot be adequately understood until considerable advance has been made in the study. It ought to present a broad, luminous picture of each branch of the subject, necessarily, of course, incomplete, but perfectly correct and intelligible as far as it goes. This picture should be 'amplified in detail by a skilful teacher. It may, however, so arrest the attention of the learner himself as to lead him to seek, of his own accord, in larger treatises, fuller sources of information. To this ideal standard of a class-book I have striven in some measure to approach. Originally, I purposed that this present volume should be uniform in size with the Class-Book of Physical Geography. But, as the illustrations were in progress, the advantage of adopting a larger page became evident, and with this greater scope and my own enthusiasm for the subject the book has gradually grown into what it now is. With few exceptions, the woodcuts have been drawn and engraved expressly for this volume. Mr. Sharman has kindly made for me most of the drawings of the fossils. The landscape sketches are chiefly from my own note-books. I have to thank Messrs. J. D. Cooper and M. Lacour for the skill with which they have given in wood-engraving the expression of the originals. 28th December 1885. |