But there is one district from which evidence has been obtained that has convinced many who sought conviction, that there were men in Britain before the first British palaeolithic tool was made. In the village of Ightham, near Sevenoaks, lives a tradesman, named Benjamin Harrison, whose discoveries have caused much searching of heart, if they have not revolutionized our knowledge of the life of early man. In 1885 he began to search for old stone implements on the chalk plateau between the valleys of the Medway and the Darent. There, embedded in patches of gravel that must have been drifted on to the plateau from hills higher still, which had been already worn down by denudation even when palaeolithic hunters were roaming among herds of mammoths in the valley of the Thames, he found flints of divers shapes which seemed to him to bear sure traces of man’s handiwork, and which have been termed ‘eoliths’, or stone implements of a dawning age. Nearly all of them, indeed, were so rude that the chipping on their edges has been ascribed by sceptics to the action of nature. But if even a small fraction of them could be proved to be authentic, the contention of their finder would be established. They recur, again and again, in certain well-defined and peculiar shapes; the chips have in many cases been removed not from the exposed parts but from concave sides which, he would have us believe, natural agents could hardly have affected;[69] if Sir John Evans and other experts are unable to accept them as artificial, Canon Greenwell,[70] Pitt-Rivers,[71] and Prestwich[72] were convinced that they had been wrought by man; even the labourers who picked them out of the gravel hardly ever failed to distinguish them from the surrounding flints;[73] and, if we may believe the champions of their authenticity, those who assert that they were shaped by nature have failed to produce stones of similar forms from the valley-drift.[74] Now when the hunters of the Thames valley were making their tools, Britain had the same main features of hill and dale that it has to-day; but when the gravels were being drifted on to the Kentish plateau, Thames and Medway were yet unborn; and, filling the great valley that now lies between the North Downs and the Lower Greensand hills, some five miles further south, the plateau rose southward to Central Wealden uplands two thousand feet or more above the sea. With no special knowledge of geology the antiquary who spends a holiday in walking from Sevenoaks or Wrotham on to the plateau may satisfy himself that this is true. Mingled with the eoliths in the patches of drift are fragments of chert that must have been washed down from the Lower Greensand at a time when it rose high above the plateau’s level; for south of the eolithic area, inclining upward below the chalk and below the Upper Greensand, the outcrop of the Lower Greensand shows itself still. The plateau drift lies upon rock of preglacial age;[75] and although there is no evidence that it is itself older than the Pleistocene period, some geologists hold that it was deposited soon after, perhaps before, British glaciers began to form.[76]