350 THE PLEISTOCENE PERIOD. 



1st. — The rock platforms are of different values, as 

 measures of the times occupied by the sea in their production 

 and this importance varies as the level rises. Thus the 25 

 feet beach appears to me to have taken a longer time to carve 

 out its platforms than the 50 feet beach, and both these to have 

 taken a longer time than the 130 feet beach (of which there is 

 but little evidence here although well established in Eng- 

 land). 



2nd. — There is an old land surface just above the 25 feet 

 beach (to be fully discussed later), which points to an arrest 

 of the rise of the sea between the two lower beaches. (See 

 diagram " Black Band," on page 353.) 



These interruptions notwithstanding, the evidence is in 

 favour of a progressive rise and a single period for them all. 

 That that period was immediately previous to the first glacial 

 deposits is evident from the fact that these deposits over- 

 lie them. That it may be seen that I am supported by 

 the writers on these deposits I shall quote, as briefly as possible, 

 several authors. 



Professor Prestwich, in a series of papers read before the 

 Geological Society in the year 1892, discussed the relation of 

 the beaches to each other and to the rubble head and valley 

 drifts. He enumerates the shells which are found in the 

 beaches and shows that they belong to a warm period. He 

 assigns the beaches (not dividing them into elevations) as of 

 one period, and that immediately before the deposit of the 

 boulder clay. In proof of the climate he shows that the 

 shells of the beaches were those cf a warm sea and states that 

 some of these are now to be found no nearer than the South of 

 Europe. 



Dr. Nils Olof Hoist commenting on the above (the Ice 

 Age in England, fol.438), says : — "In the Selsey Beach, the 

 lower layer yields a marine molluscan fauna with forms of so 

 southern a character that they have now to be sought as far 

 down as the Coast of Portugal. This " Raised Beach " 

 depression is clearly p re-glacial. 



Mr. Clement Reid, in a paper read before the Geological 

 Society ( Transactions, Feb. 1892, p. 346), says : — " Professor 

 Prestwich in 1858 announced the discovery of a raised beach 

 at Portsdown, at a height of 125 feet. The work of the 

 survey having thoroughly corroborated Professor Prestwich's 

 view that these deposits all belong to one period, there will be 

 no occasion here to discuss the question." 



In view of the above statements it seems unnecessary to 

 quote other authors, although such quotations are at hand. 



