FIG. 203. Helladotherium Duvernoyi-a gigantic animal intermediate in structure between the giraffe and the antelope, Pikermi, Attica 204. Pleistocene or Glacial Shells 205. Mammoth from the skeleton in the Musée Royal, Brussels 208. Antler of Reindeer found at Bilney Moor, East Dereham, Norfolk CHAPTER I. INTRODUCTORY. THE main features of the dry land on which we live seem to remain unchanged from year to year. The valleys and plains familiar to our forefathers are still familiar to us, bearing the same meadows and woodlands, the same hamlets and villages, though generation after generation of men has meanwhile passed away. The hills and mountains now rise along the sky-line as they did long centuries ago, catching as of old the fresh rains of heaven and gathering them into the brooks and rivers which, through unknown ages, have never ceased to flow seawards. So steadfast do these features appear to stand, and so strong a contrast do they offer to the shortness and changeableness of human life, that they have become typical in our minds of all that is ancient and durable. We speak of the firm earth, of the everlasting hills, of the imperishable mountains, as if, where all else is fleeting and mutable, these forms at least remain unchanged. And yet attentive observation of what takes place from day to day around us shows that the surface of a country is not now exactly as it used to be. We notice various changes B 2 ...INTRODUCTORY. [CHAP. of its topography going on now, which have doubtless been in progress for a long time, and the accumulated effect of which may ultimately transform altogether the character of landscapes. A strong gale, for instance, will level thousands of trees in its pathway, turning a tract of forest or woodland into a bare space, which becomes perhaps a quaking morass, or may be changed into arable ground by the farmer. A flooded river will in a few hours cut away large slices from its banks, and spreading over fields and meadows, will bury many acres of fertile land under a covering of barren sand and shingle. A long-continued, heavy rain, by loosening masses of earth or rock on steep slopes, causes destructive landslips. A hard frost splinters the naked fronts of crags and cliffs, and breaks up bare soil. In short, every shower of rain and gust of wind, if we could only watch them narrowly enough, would be found to have done something towards modifying the surface of the land. Along the seamargin, too, how ceaseless is the progress of change! In most places, the waves are cutting away the land, sometimes even at so fast a rate as two or three feet in a year. Here and there, on the other hand, they cast sand and silt ashore so as to increase the breadth of the dry land. These are ordinary everyday causes of alteration, and though singly insignificant enough, their united effect after long centuries cannot but be great. From time to time, however, other less frequent but more powerful influences come into play. In most large regions of the globe, the ground is often convulsed by earthquakes, many of which leave permanent scars upon the surface of the land. Volcanoes, too, in many countries pour forth streams of molten rock and showers of dust and cinders that bury the surrounding districts and greatly alter their appearance. Turning to the pages of human history, we find there the records of similar changes in bygone times. Lakes, on which our rude forefathers paddled their canoes and built their wattled island-dwellings, have wholly disappeared. Bogs, over whose treacherous surface they could not follow the chase of red deer or Irish elk, have become meadows and fields. Forests, where they hunted the wild boar, have been turned into grassy pastures. Cities have been entirely destroyed by earthquakes or have been entombed under the piles of ashes discharged from a burning mountain. So great have been the inroads of the sea that, in some instances, the sites of what a few hundred years ago were farms and hamlets, now lie under the sea half a mile or more from the modern shore. Elsewhere the land has gained upon the sea, and the harbours of an earlier time are now several miles distant from the coast-line. But man has naturally kept note only of the more impressive changes, in other words, of those which had most influence upon his own doings. We may be certain, however, that there have been innumerable minor alterations of the surface of the land within human history, of which no chronicler has made mention, either because they seemed too trivial, or because they took place so imperceptibly as never to be noticed. Fortunately, in many cases, these mutations of the land have written their own memorials, which can be as satisfactorily interpreted as the ancient manuscripts from which our early national history is compiled. In illustration of the character of these natural chronicles, let us for a moment consider the subsoil beneath cities that have been inhabited for many centuries. In London, for example, when excavations are made for drainage, building, or other purposes, there are sometimes found, many feet below the level of the present streets, mosaic pavements and foundations, together with earthen vessels, bronze implements, ornaments, coins, and other relics of Roman time. Now, if we knew nothing, from actual authentic history, of the existence of such a people as the Romans, or of their former presence in England, these discoveries, deep beneath the surface of modern London, would prove that long before the present streets were built, the site of the city was occupied by a civilised race which employed bronze and iron for the useful purposes of life, had a metal coinage, and showed not a little artistic skill in its pottery, glass, and sculpture. But down beneath the rubbish wherein the Roman remains are embedded, lie gravels and sands from which rudelyfashioned human implements of flint have been obtained. Whence we further learn that, before the civilised metal-using people appeared, an earlier race had been there, which employed weapons and instruments of roughly chipped flint. That this was the order of appearance of the successive peoples that have inhabited the site of London is, of course, obvious. But let us ask ourselves why it is obvious. We observe that there are, broadly speaking, three layers or deposits from which the evidence is derived. The upper layer is that which contains the foundations and rubbish of modern London. Next comes that which encloses the relics of the Roman occupation. At the bottom lies the layer that preserves the scanty traces of the early flint-folk. The upper deposit is necessarily the newest, for it could not be laid down until after the accumulation of those below it, which must, of course, be progressively older, as they are traced deeper from the surface. By the mere fact that the layers lie one above another, we are furnished with a simple |