OF GEOLOGY DESCRIPTIVE AND INDUSTRIAL BY DAVID PAGE, F.G.S. AUTHOR OF "INTRODUCTORY TEXT-BOOK OF GEOLOGY," " HANDBOOK OP SECOND EDITION, REVISED AND ENLARGED WILLIAM BLACKWOOD AND SONS MDCCCLIX The Right of Translation is reserved. PREFACE. 66 THIS Treatise, while intended as a sequel to the Author's Introductory Text-Book," has been prepared throughout as a separate and independent work. The purpose of these Text-Books is briefly this: The Introductory is meant to exhibit an outline of Geology intelligible to beginners, and sufficient for those who wish to become acquainted merely with the leading facts of the science; the Advanced, on the other hand, presents the subject in detail, and is intended for senior pupils and those who desire to prosecute the study in its principles as well as deductions. Though thus prepared on the same plan, and the one but an extension and development of the other, they are both independent elementary works, and may be taken separately or in sequence, according to the progress and purpose of the student. This much may be said, that he who has mastered the Introductory will have nothing to unlearn when he comes to study the Advanced, while his acquisition of the science will have been rendered much more easy and agreeable. The Author has a strong conviction on this point. In teaching the construction of the steam-engine, for instance, the most natural course is to explain, in the first place, its more prominent features-its boiler, steam-pipe, cylinder, piston, crank, and fly-wheel; and when the learner has acquired a knowledge of the relations of these parts, and the force which sets them in motion, then to proceed to the more intricate connection of valves, condenser, hot-well, air-pump, eccentric rods, governor, and other complicated machinery. By adopting this course, no confusion is created in the mind of the learner; he is impressed with gradual and permanent convictions; has nothing to unlearn; and may at length proceed with some degree of confidence to estimate the power of the entire machine, as depending on the consumption of fuel, the elasticity of steam, the dimensions of the several parts, and the force lost through friction. So it is with every science: Let an outline be given of its leading features, that the beginner may arrive at some notion of its purport and bearings; let this be followed by the details; and the details by the higher reasonings and philosophy of its problems. Under this conviction. these volumes have been prepared; and it will be a source of unmingled satisfaction to the Author to find his views corroborated by the experience of intelligent and competent teachers. One word to those who may object that these Text-Books do not contain enough of the "hard facts" of the science. It had been an easy matter for the Author to have loaded his pages with minute mineral distinctions, enumeration of localities, and lists of fossil species; but had he done so, he could not have chosen a more effectual plan to disgust the learner and retard his progress. What he has aimed at was the production, not only of class-books for schools, but readable manuals for self-instruction-treatises that in their readableness might imbue the student with the spirit and methods of Geology, rather than cram him with its details, many of which, in the progressive state of the science, are merely temporary and provisional. Once furnished with proper methods, and imbued with the right spirit, the earnest student has in general little difficulty with details-every acquisition of his own not only widening the basis of his knowledge, but increasing his power to master new difficulties as these may arise in the course of his onward progress. Still more to foster this spirit, the Author has endeavoured to write as he would have spoken to a junior companion in the field-hopefully and encouragingly, yet not disguising the real difficulties that lie in the way-treating the subject as one to which the humblest observer may contribute his mite, rather than attempting to propound authoritatively on problems, the satisfactory solution of which involves a much wider range of observation, and deeper and more exact research, than Geology as yet can boast of. Yet another word: The Author requests his brother geologists who may glance over these pages to remember that they are not intended to contain an exposition of his own peculiar views, but rather to exhibit an elementary outline of the science as now established by the leading workers in Britain, France, Germany, and America. The main object has been to render the student such assistance as will enable him to proceed in the field as a practical observer, and to read with appreciation the higher treatises, special monographs, papers, and new discoveries of others. To further this object mention is made, at the end of each section, of the principal works devoted to the department in question; to have done more would have been to enter on the field of speculative geology-a subject that lies beyond the scope of an educational Text-book. GILMORE PLACE, EDINBURGH, March 1856. |