8 CHEStL BEACH. 



must ask your attention for a moment to a point in connection 

 with the Chesil Beach, which has an indirect bearing also on the 

 raised beach at Langstone Ope, a place we are expecting to see 

 later in the day. Nothing in the physical world stands still, and 

 so far as the movement of the shingle up and down the beach is 

 concerned that is sufficiently obvious, but such movements 

 merely relate to the oscillations of pebbles according as each 

 set of wind-waves prevail. There is, however, as pointed out by 

 Mr. Strahan, a proper motion of the whole Beach towards the 

 land. The shelf of clay on which it rests is obviously the result 

 of marine erosion. In great gales the waves erode the base and 

 carry stones over the top, so that the beach increases in this 

 direction and is slowly travelling landwards. If my previous 

 remarks as to the sources of supply of pebbles are correct, this 

 landward motion of the beach seems almost to follow ; at the 

 same time it is not obvious to the physical eye, and the notion 

 of this movement inland must be regarded in the light of a 

 probable hypothesis. The movement is thought to have been 

 most considerable at the Portland end, whilst the Bridport end 

 is viewed as almost stationary. Thus Mr. Strahan represents the 

 movement as a swinging one, and he seems disposed to suggest 

 some connection between the Chesil Beach of to-day and the 

 raised beach of the past.'^' 



Protection afforded by the Beach. — The last point we have to 

 consider is a more practical one than any of the others. We are 

 told by the poet that " Britannia needs no bulwarks," but this is 

 certainly not true in a physical sense, for the value of shingle 

 beaches to the greater part of the south coast of England is very 

 great indeed, as the most casual observer can testify. Nowhere 

 are there stronger evidences of this preservative action of a 

 shingle beach than in the case now before us, I have already 

 indicated the nature of this action in connection with the 

 history of the Fleet. But the shape of Lyme Bay is eminently 



* Since the party was unable to get to Langstone Ope on account of the 

 weather the further consideration of this hypothesis is deferred. 



