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climate conditions would be entirely altered, even if the combined 

 rainfall and snowfall were no greater than now. During the long 

 winter, erosion would almost cease, but during the spring the 

 rainfall and the melting of the snow accumulated during several 

 months would cause floods such as we now never see in the south 

 of England. Not only so, but the formation of bottom or anchor- 

 ice, and the floating off of large cakes of ice laden with stones 

 would clear away and sweep down the streams large boulders such 

 as no flood nowadays can move. This again would help to keep 

 the channels clear and allow a greater sweep for the floods. 



Under Arctic conditions the sea-coast would show a wide belt 

 of ice-foot or shore-ice under the cliffs, and this would in winter 

 deaden the action of the waves. Thus there would be little change 

 In winter, except for the universal shattering and loosening of 

 every cliff-face not protected by snow. In spring, however, this 

 would be entirely altered. First, the shattered cliff-faces towards 

 the sun would thaw and fall on to the ice-foot. Then, as spring 

 advanced, the gales and tides would loosen this ice-foot, and it 

 would float away in large cakes, not only with its burden of fallen 

 blocks, but with a quantity of imbedded beach stones frozen into 

 its substance. These boulders and pebbles which, under existing 

 climatic conditions, tend to accumulate on the beach and protect 

 the foot of the cliff, would, under Arctic conditions, be swept out 

 to sea and dropped into deep water. Thus the cliff itself, 

 unprotected by beach, was left exposed to the grinding and 

 undercutting caused by the drifting to and fro of the ice with every 

 tide. 



Imagine what this would mean at places like Hengistbury 

 Head or at Swanage. In both these places the cliff is now 

 protected by a talus of large fallen blocks. Consider what would 

 happen if a winter's ice enclosed all this coarse material, lifted it, 

 and swept it out to sea, thus leaving the cliff-foot undefended from 

 the ice. Probablv the annual loss of land would be at least ten 

 times what it is now. 



I particularly want you to realize this effect of the cold, for 

 people often say that sea and rivers work very slowly, and that 

 therefore great changes such as are depicted on the map must 

 have taken an enormous time. They say also that if man saw 

 great changes of this sort his first appearance in this country must 

 be so ancient as to point to the lapse of millions instead of 

 thousands of years. This idea is erroneous, for as soon as Arctic 

 conditions supervene, the rapidity of the changes is enormously 

 increased — and we know that Britain under Arctic conditions was 

 alreadv inhabited by man. 



I do not want to suggest that the whole of the strata which 

 contain evidence of man's handiwork can be brought into a few 

 thousand years. I only want to point out that the rapidity of the 

 changes in phvsical geography, in the fauna, and in the flora — and 

 these changes are the scales by which we usually measure 

 geological time — are governed to a large extent by climatic 

 conditions. However, as regards the period of first or maximum 



