The evidence from which these reconstructions of the former aspect of the country and its inhabitants can be deduced lies easily accessible around us. From the numerous caves in the limestone districts, abundant remains have been disinterred of the land-animals that were contemporary with aboriginal man, and among them relics of human workmanship have likewise been obtained. Our bogs have yielded skeletons of the Irish elk and other denizens of the primeval glades and woodlands, together with the canoes and stone-implements of the hunters of these animals. Our river-terraces reveal a long history of climatal changes onward from the later phases of the Ice-Age, during which the country witnessed successive migrations of northern and southern mammals accompanied by Palaeolithic and Neolithic men. The raised beaches and sunk forests contain relics of contemporary human workmanship which prove that man had already become an inhabitant of Britain before the land had settled into its present level above the sea. It may be of advantage to consider here, from the various sources of information above enumerated, what appears to have been the condition of the surface of Britain at the dawn of authentic history and what have been the nature and origin of the changes which this surface has undergone within historic time. When the light of human testimony first begins to fall upon Britain at the advent of the Romans, the general aspect of the country must have presented in many respects a contrast to that which is now to be seen; and notably in the wide spread of its forests, in the abundance of its bogs and fens, and (through the northern districts) in the vast number of its lakes.