342 THE PLEISTOCENE PERIOD. 



The Scotch raised beaches are also at the two levels ; but 

 there is reason to think that they alternate in time with the 

 English beaches of the same level. 



Dr. Nils Olof Hoist, already referred to, of the Swedish 

 Geological Survey, has discussed these levels (Geological 

 Magazine, Nov. 1915, p. 512). Speaking of glacial time, he 

 says " Scotland rose, and England sunk, when the one went 

 up the other went down, probably both the up and down 

 movements increased with the distance from the fulcrum " 

 which he places on the border. The land thus behaved like 

 a see-saw. In this way he accounts for an alteration of sea- 

 level between the sout ; of England and the 25 and 50-feet 

 beaches of Scotland. 



Sir J. Prestwich includes under the term Raised Beach 

 Period all elevations, and they are many, but does not, in his 

 paper, clearly indicate their order of deposition or their 

 correctly ascertained elevations. The truth is that owing to 

 the depths or! the original deposits and the unknown portion 

 of each deposit, which has left, but a small remnant, there must 

 always be a difficulty in knowing these elevations ; but I may 

 say, that having tabulated a number I think it will be suffi- 

 ciently correct and convenient to use the round figures of 

 25, 50, 70, 125, 175 and 300 ft. to cover the various elevations 

 discussed by the writers who describe them. 



The want of clearness on Prestwich's part will be evident. 

 He recognises on the South coast a level of 25 feet; this he 

 continues all around the coasts of Cornwall and on both sides 

 of the Severn. He describes an elevation at Newhaven of 

 50 feet. At Portsdown one of under 100 feet. At Hopes 

 Nest he describes an overhanging mass of conglomerate at an 

 elevation of 50 feet. 



THE RAISED BEACHES. 



I have, so far, treated of sea-levels as fixed by caves and 

 their associated beaches. I now treat of the beaches them- 

 selves which I shall divide into two series : 1st, the low r er and 

 well marked beaches, and 2nd, the higher and less well defined. 



THE LOWER RAISED BEACHES. 



Before entering on any argument founded on the beaches 

 I shall describe them in sufficient detail. 



Above the present beach, now in course of formation, is 

 an old deposit which, owing to its extreme age is consolidated 

 into a firm conglomerate. The base of this formation is just 

 above high water mark. The mean height of all the deposits 

 is 25 feet above mean sea-level (O.D.). 



