of human manufacture, flints with bruised and battered edges, which I and some others venture to regard as owing their shape to purely natural causes. But fortunately this does not invalidate his arguments, as in most cases where the so-called "Plateau types" have been found, more or less well-finished palæolithic implements of recognized form, though much abraded and deeply stained, have also been discovered. The evidence of such witnesses is not impaired by calling in that of others of more doubtful character.
Fig. 456a.—Bewley, Ightham. 12
The continuous slope now extending from the neighbourhood of the Thames to the summit of the Chalk escarpment, and in many places capped with implementiferous drift, appears to have been continued southward within the human period over a part of what is now the Lower Greensand area, if not, indeed, into that of the Weald; and subsequently the great valley that now intervenes between the Lower Greensand escarpment and the North Downs must have been excavated.
Whatever causes we may assign for the changes in the surface-configuration of the district, it must be borne in on all that the time required to effect them is beyond all ordinary means of calculation.
West of Ightham, at the head of the present valley of the Darent, is Limpsfield,[1] the scene of some interesting discoveries
- ↑ Proc. Geol. Assoc., vol. xi. p. lxxxii.
