If the primeval efforts of the human imagination were thus stimulated by the more impressive features of the outer world, it is natural to believe that the same external influences would continue to exert their power during the later mental development of a people. In particular, it seems reasonable to anticipate that such potent causes would more or less make themselves felt in the growth of a national literature. The songs and ballads of the plains might be expected to present some marked diversities from those of the mountains. There may, of course, be risks of error in generalisations of this kind, especially where the writings of distinct races are compared with each other. But the risks may be reduced if we confine ourselves to the consideration of a single country and a single literature. Such at least is the task which I have undertaken on the present occasion. I propose to discuss the leading types of scenery that distinguish the British Isles, and to inquire how far it may be possible to trace from each of them an influence upon the growth of English literature as shown in our poetry. Under the term scenery may be included those variations in the general aspect of the land that arise from the combined effects of three main geographical elements--topography, climate, and vegetation. Of these three factors, we are mainly concerned with the first, but the other two will necessarily obtrude themselves continually on our attention. Although geological details are not essential for the inquiry before us, nevertheless some knowledge of them will be found of service in enabling us to recognise more clearly the essential features of a landscape, and to discriminate the real nature and extent of the diversities between the landscapes of different parts of the country. The fundamental elements of the scenery depend upon the nature and structure of the rocks that come to the surface, and the manifold varieties of external form arise from the constant succession of different geological formations.