In the following chapters we shall look, so far as possible, at those aspects of the subject which make the widest appeal, and which are best fitted to enable the ordinary man to understand his surroundings, whatever they may be, and so aid him in that delicate task of adjustment which, consciously or unconsciously, is the task of every living thing. As limitations of space involve a similar limitation of subject-matter, it has been thought best to lay most stress upon the conditions which prevail in Europe and North America, the areas which have been most thoroughly studied. Europe has the special interest that it has given origin to the type of civilisation which has most profoundly modified the earth's surface. This limitation cannot, however, be made rigid, for it is of the essence of the modern standpoint that no area can be understood without reference to the world at large. The geography of Europe no less than of North America is determined by the position of the respective continents on the surface of the globe, and cannot be understood without a consideration of this position and its implications. The standpoint adopted here is frankly anthropological, that is, the world is considered as the home of man, its physical peculiarities being regarded as interesting chiefly in their relation to man and his activities. Finally, we may note that the development of the subject within recent years has been such that it is quite impossible, even within the limitations already laid down, to give a complete survey of the subject. All that will be attempted, therefore, is to suggest some of the lines along which research is proceeding most actively at the present time, special stress being laid upon those aspects of the subject which are not as yet fully treated in the smaller text-books. The list of books of reference at the end will, it is hoped, enable those interested to fill in the blanks which such a scheme necessarily leaves. CHAPTER II SURFACE-RELIEF AND THE PROCESS OF EROSION It is not necessary here to consider the various formal definitions of geography which have been proposed in the last few years. As is only natural with a developing subject, much discussion has taken place as to the exact limits of its field of action, and many definitions have been proposed with the object of setting forth these limits as clearly as possible. But it is sufficient for our purpose to note that geography deals with the surface-relief of the earth, and with the influence which that relief exercises upon the distribution of other phenomena, and especially upon the life of man. Before we proceed to study detailed problems, then, it is obviously necessary to look at some general points connected with the relief of the earth's surface and its causes.