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given, it will I hope be clear that in these as in all valleys, 

 ice must have sometimes collected, and the surface being 

 frozen and impervious, the ice-laden and tumultuous floods 

 of summer would have a scouring power even greater than 

 water. There can be little doubt that the glaciation was not 

 merely annual but sometimes of long continuance, and if 

 actual glaciers or ice rivers did not occupy the valleys, 

 they must in certain situations have got completely choked 

 with ice and chalk debris. The pressure exerted by this 

 was of course great, and much greater when there was a 

 thaw, from the ponded water ; consequently in certain situa- 

 tions, as at the sharp bends in valleys it was exerted on the 

 elbow or projecting ground round which the valley wound. 

 In such situations then we find the required evidence in the 

 distorted and crushed chalk and other strata. Take for 

 instance, an instance near Weight's Farm, when the chalk 

 [seen in a pit] has been crushed and moved over itself, 

 leaving spaces between the blocks, while the layers of flint 

 may be seen crushed to dust, this is visible to a depth of 

 20 feet. 



But there are so many situations where this effect may 

 be observed that it is not necessary to enumerate more. 

 A similar cause dislocated and folded the Oldhaven beds 

 in the Erith ballast pit, at a spot where two unequally deep 

 valleys joined, before referred to. In the elbow of the 

 pebble beds, where the Bromley station, L. C. D..R., stands 

 the pebbles have been deeply pitted, as usual in a normal 

 state, but besides that, they have been moved or rotated 

 past each other in a horizontal direction, as shewn by the 

 scores and scratches impressed on them, and this I think 

 has been caused by the horizontal pressure from the blocked 

 stream way, which running North from Keston to South- 

 boro,' turns sharply Southward for a few yards before 

 joining the main stream of the Ravensbourne running 

 from Hayes. 



The dry valleys are often found deeply filled with flints 

 weathered, not waterworn, and whitened by long exposure 



