i894. PLATEAU IMPLEMENTS OF KENT. 271 



Weald, which was ultimately to be an elevated, elliptical, weather- 

 worn, and sea-eaten dome of great height. 3 

 The successive stages were : — 



1. When the elevation of the Wealden area attained its 

 maximum, there was certainly a considerable thickness of Chalk on 

 the surface, and this was necessarily exposed to marine and atmos- 

 pheric denudation. 



2. The immediate result of this was the wearing-away of the 



s _-- , - 



Fig. I. — Diagram showing roughly the relative position of the formations 

 constituting the Wealden Anticlinal between the North and South Downs (i. Limps- 

 field, 876 ft. ; 2. Oldbury, 620 ft. ; 3. Crowborough, 803 ft.) ; also their successive 

 denudations ; and the original place of the Old Gravel (4), some of which was 

 brought down by natural agencies to the Chalk Plateau (5) now existing. 



Ch 



I.'.;.'<f.?5.^!. 



•'ia.i<:....J r..-. 



""Larret. Gyf-.f.T?:?.^^-^ 



Fig. 2. — Diagram showing the possible position of the Lower Greensand outcrop 

 (C) when the Old Gravel {A) was being transferred from the higher (A) to the lower 

 (B) level of the Chalk by natural agencies along a continuous surface. The strata 

 are set at too high an angle in Fig. i to show what is required here. 



{A) Old Gravel in place. (B) Plateau Gravel derived from the Old Gravel. 

 (C) Outcrop of the Lower Greensand. 



Chalk, and the trituration of the washed-out flints ; and thus the- 

 formation of a great bed of shingle — that of the Thanet Sands. 



3. With continued wave-action, these shingle-banks were washed 

 away and distributed at a lower level, to be the Pebble-beds of the 

 " Woolwich and Reading " series, which had been formed in the 

 meantime by rivers from the hill-ranges. The pebble-beds can now 

 be seen at Addington, Blackheath, etc., extending to the very edge 

 of the present Chalk escarpment. 



4. The deposits of this stage were next removed in part ; and in 

 course of time the Diestian beds were laid against the flanks of the 

 lowered and perhaps sinking range. Of these strata some limited 

 patches, such as the Lenham beds, remain here and there on what 

 are now the Chalk Downs. 



5. One or more accumulations of Chalk-flint debris were formed 



8 A neat little diagrammatic section across the Wealden area, showing the high 

 elevation of the anticline (about 2,000-3,000 feet ; Top ley, Mem. Geol. Surv. JVeald., 

 1875, P- 217), was published in Professor (Sir A.) Rams ay's " Lectures on the Physical 

 Geology and Geography of Great Britain " (five editions, 1S63-187S). At the time 

 oi this elevation of South-eastern England, the Ardennes attained a height of about 

 18,000 feet, as shown by MM. Cornet and Briart, Mim. Soc. gcol. Belgique, vol. iv.,. 

 p. 71. 



