53 



very much slower, but must be always going on so long as the 

 iviin falls and the river flows. 



Having cousidored tho salient features of the county to the 

 northward of Canterbury and tho coast -line from the Isle of 

 Sheppey to Dungoncss, in their relation to the geological 

 structure of tho district, we may by following a line drawn in a 

 southerly direction to Hastings, continue an instructive field 

 sketch of the surface geology. Al)Out ton miles from Cantor- 

 bur}' in this direction we reach the southern escarpment of the 

 chalk, which forms a l)old line of inland cliffs rising in places, 

 as at Folkestone-hill, to a height of 347 feet, surrounding the 

 Weald of Kent and Sussex, to make use of a military simile, 

 like tho outer line of a fortified position with an inner line of 

 rampart formed by the Lower G-reensand. The two valleys of 

 the Grault and Weald clays, forming tho ditches between each 

 escarpment and the Hastings sands, which latter may be 

 supposed to represent the citadel. Tlie whole Wealden area be- 

 ing in this manner surrounded on the north, west, and south, 

 the sea has cut tlirough all the formations without respect to 

 their lithological character on the eastern side, thus completing 

 the imaginary line of defence. 



Carrying out the analogy of a fortified place the five rivers on 

 the north, the Stour, Medway, Darent, ]\[ole, and Wey, and tho 

 foui' corresponding ones on tho south, the Cuckmero, Ouse, 

 Adur, and Aruu, form as it were, by the valleys tliey have ex- 

 cavated, so many sallyports. Eeturuing to the chalk escarpment 

 between Folkestone and Ashford, we may look across the two 

 valleys indicated, to the central high ground of tho Hastings 

 sands. The chalk escarpment bears such a strong resemblance 

 to an old sea cliff against which the waves at one time beat, with 

 all tlio coast-line features of bay and headland, that such a con- 

 clusion with regard to their formation seems inevitable, but we 

 shoidd not be justified in concluding from mere appearances such 

 to be the case. Sea cliffs are cut Ijy the ceaseless action of the 

 waves independently of tlie strike or dip of the rocks, fre- 

 quently at right angles to tho strike as at Dover, Folkestone, 

 and iieacliy Head, no bays of any considerable depth being 

 formed even where the coast consists of the softer strata com- 

 posing the valleys of the Gault and AVoald clays. Tho sea 

 generally leaves evidence of its action in shingle, sands, and the 

 coimtless I'emains of tho living; things of the sea. Combes, 

 those peculiar semi- circular hollows in tho chalk escarpment, 

 do not occur in the chalk cliffs, now washed by the sea. 

 From tho nature of the chips left by a carpenter we may judge 

 of the tools that he has been using, the sawdust, shavings, or 

 chisel chips, are evidence of tho tools that produced them, but 

 when the broom has swept all such traces away we have only the 



