HEADLANDS AND BAYS. 123 



were more easily worn away because they had been already bent and 

 broken by stretching along the axis of their upward bend. The 

 excavation was a gradual process. In the south-west the English 

 Channel commenced to be formed at an early period. The Channel 

 is deeper in that direction, and therefore presumably older. It is 

 impossible to determine how much of the excavation has been accom- 

 plished by ordinary waste along sea- cliffs, as the land was raised so 

 as to bring every portion of a valley successively under the power of 

 the breakers, and how much may have been worn away during the 

 long ages for which its whole area remained in the condition of dry 

 land, and exposed to the action of rain and winds and frost and rivers. 

 It is probable, however, that these two powers, alternating with each 

 other, have widened the Channel slowly in the way in which we see 

 it widening in parts at the present day, by the waste of cliffs when 

 they are undermined by the sea, and sawn out into gulleys by the 

 land-springs which pour over them. Perhaps the most instructive 

 parts of our cliff scenery are those which show the intimate connec- 

 tion of the island with the continent. All along the south coast from 

 the Straits of Dover to Cornwall, the rocks of South Britain and the 

 opposite coast of France face each other as though cleft asunder. 



But besides its direction, every shore presents the minor features of 

 bays, inlets, cliffs, and capes, whose existence is only intelligible by 

 help of a knowledge of the ways in which the several geological 

 formations which make up the dry land have been accumulated, 

 folded, and upheaved so that the edges of strata are exposed on the 

 shores where land rises out of the sea. 



Headlands. This dependence of headlands upon geological forma- 

 tions is well exemplified in Flamborough Head, in the North and South 

 Foreland, in the promontory of Beachy Head, and in Culver Cliff and 

 the Needles at the east and west ends of the Isle of Wight. All these 

 headlands consist of chalk, and although chalk may be worn away by 

 the sea like any other formation, when acted upon by the grinding 

 power of the breakers, it cannot be disintegrated and washed up into 

 easily-transported sediment like the underlying and overlying sands 

 and clays. Hence, since its removal is largely dependent upon the 

 chemical power of water to dissolve the limestone and take it up into 

 invisible suspension, the rock is more enduring than the associated 

 deposits which rest upon it and which it covers. And being a thick, 

 homogeneous formation, which often has its fore-shore defended with 

 a barrier of flint derived from the waste of the Upper Chalk already 

 destroyed, it happens that this formation juts out into the sea, while 

 on each side of it the strata are excavated by tidal attrition into bays. 

 Of such bays Sandown Bay and Compton Bay are familiar examples, 

 due to the removal of the soft underlying strata below the Chalk. 



But the sea is often admitted into the land without any regard 

 to nature of the strata, simply because they happen to be bent down 

 into a trough, part of which sinks below the sea-level. This is the 

 case with the estuary of the Thames and the Southampton Water, 

 both of which owe their existence chiefly to lying in synclinal folds, 



