i894. PLATEAU IMPLEMENTS OF KENT. 273 



The probably great changes of climate, due to rearrangements 

 of land and water and of high and low ground, form part of Professor 

 Prestwich's interesting history of the Wealden hill-ranges, in the 

 sculpturing of which not only aqueous, but glacial agency must have 

 had a large share. 



It must have been a great pleasure to the veteran geologist, 

 Professor Dr. Prestwich, to find that his conclusions (in 1890) as to 

 the Pliocene Tertiaries and gravels on the flanks of the diminishing 

 island of the Weald fitted so truly, as consecutive history, with his 

 early views (1847) of the probable conditions of the Wealden dome in 

 Eocene times. 



Perhaps it may be asked : — 



I. — Why may not the Rude Implements belong to the Red 

 Clay-with-flints, since some few have been obtained in shallow 

 diggings on that bed ? 



The reply is : — i. Because that clay was not ever moved about, 

 much less drifted. 



2. Because that clay occurs over other and larger areas without 

 containing any such implements, but only unrolled flints separated 

 from the Chalk by its dissolution. 



3. Because the implements are accompanied with chert and 

 ragstone from the Lower Greensand, which dehris must have come 

 from a higher level — namely, from the outcrop of the Lower 

 Greensand on the side of the hill-ranges of the " Dome," before the 

 denudation of the present Gault valley. 



4. If the Implements had settled down from above with the 

 " Clay-with-flint," they must h.3ive either heen in the Tertiaries (!) to 

 be let down, as the Chalk dissolved below (possibly when the 

 Chalk had a somewhat higher slope against the " Dome "), — or they 

 must have been on the Chalk before the Tertiaries were formed there ! ! 



5. The " Red Clay-with-flints " is of local origin, whereas the 

 rude implements, with the sprinkling of brown gravel, are foreign to 

 the place of their occurrence. And on the surface, where these 

 implements are found, chert and ragstone from the Lower Greensand 

 always occur. 



6. Professor Prestwich infornis me that he has examined 

 hundreds of sections of the " Red Clay-with-flints," and has never 

 found the implements in it. Some of the reputed cases of their 

 presence in this clay are doubtful. In other cases, mentioned by Mr. 

 Harrison (see the list on next page), the depth is so small that the 

 implement may have worked itself down, or may have fallen into a 

 hole. 



7. The flints in the red clay are not stained. The crust of the 

 flint retains its white colour ; or, if the flint has been broken, the 

 surface of fracture has weathered white. The red clay does not stain ; 

 it seems to have removed the water-of-crystallisation, and left a white 

 surface on the flint. 



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