It is picked out from amongst ordinary stones partly because of its shape, and partly because of rough and much-worn chippings that suggest the hand of art or of nature, according to your turn of mind.  Take one by itself, explains Mr. Harrison, and you will be sure to rank it as ordinary road-metal.  But take a series together, and then, he urges, the sight of the same forms over and over again will persuade you in the end that human design, not aimless chance, has been at work here.

Well, I must leave Mr. Harrison to convert you into the friend or foe of his eoliths, and will merely add a word in regard to the probable age of these eolith-bearing gravels.  Sir Joseph Prestwich has tried to work the problem out.  Now-a-days Kent and Sussex run eastwards in five more or less parallel ridges, not far short of 1,000 feet high, with deep valleys between.  Formerly, however, no such valleys existed, and a great dome of chalk, some 2,500 feet high at its crown, perhaps, though others would say less, covered the whole country.  That is why rivers like the Darenth and Medway cut clean through the North Downs and fall into the Thames, instead of flowing eastwards down the later valleys.  They started to carve their channels in the soft chalk in the days gone by, when the watershed went north and south down the slopes of the great dome.  And the red gravels with the eoliths in them, concludes Prestwich, must have come down the north slope whilst the dome was still intact; for they contain fragments of stone that hail from right across the present valleys.  But, if the eoliths are man-made, then man presumably killed game and cut it up on top of the Wealden dome, how many years ago one trembles to think.

* * * * *

Let us next proceed to the subject of palaeoliths.  There is, at any rate, no doubt about them.  Yet, rather more than half a century ago, when the Abbe Boucher de Perthes found palaeoliths in the gravels of the Somme at Abbeville, and was the first to recognize them for what they are, there was no small scandal.  Now-a-days, however, the world takes it as a matter of course that those lumpish, discoloured, and much-rolled stones, shaped something like a pear, which come from the high terraces deposited by the Ancient Thames, were once upon a time the weapons or tools of somebody who had plenty of muscle in his arm.  Plenty of skill he had in his fingers, too; for to chip a flint-pebble along both faces, till it takes a more or less symmetrical and standard shape, is not so easy as it sounds.  Hammer away yourself at such a pebble, and see what a mess you make of it.  To go back for one moment to the subject of eoliths, we may fairly argue that experimental forms still ruder than the much-trimmed palaeoliths of the early river-drift must exist somewhere, whether Mr. Harrison’s eoliths are to be classed amongst them or not.  Indeed, the Tasmanians of modern days carved their simple tools so roughly,