352 THE PLEISTOCEXE PERIOD. 



the sea margin was well inland and that, the sea washed the 

 West foot of the Vardes hill. At Courtil Bas, situated between 

 the Vardes hill and Mont diet, the quarry cutting is lined on 

 both sides with a deposit of this beach, but here we have 

 proof that no eroding agent was at work, for the pebbles are 

 not laid flat as is the case elsewhere, but are all at aslope, 

 showing that here is the top of the beach, and came to rest on 

 the land side. Here then we have a good measure of the 

 position of the extreme high water mark. The mean height 

 of the deposits on the sea face is here just under 24 feet, and 

 at the Courtil Bas the height of the beach-ridge is 29*6 feet. 

 The pebble deposit of the beach had therefore a range of 

 about 10 to 12 feet in this part of its coast-line. 



If we give full weight to this fact and to the beds to be 

 described in the next part, we must, I think, look upon the 

 different beach-levels as different sea-levels. 



Thus then we establish the fact that warm sea stood at 

 the beginning of the Pleistocene Period for a long time at an 

 average of 25 feet above the level of the present sea. 



The steadiness of the sea-level was due to the fact that 

 its rise was interrupted and a short fall alternated. 



If we realise the idea of points of stability, we see that 

 oscillations of level are to be looked for and it has recently 

 come to our knowledge that there are indications of such an 

 oscillation. 



We have evidence that when the 25 feet beach was begun 

 the land was sinking, or what is the same thing in effect, the 

 sea was rising, we need not discuss the alternative at present, 

 and we also know that a temporary halt in the rise set in. 

 This arrest assisted both in diminishing the lange of the 

 beach and in flattening it. It will be asked, what evidence 

 have we of this ? 



That the land was higher before the beach was formed 

 is proved by the presence of cliff-falls of rubble which are 

 found immediately below it, in places. The best example of 

 this is found in the Belcroute Bay section as shown by 

 Mr. Sinel in his " Prehistoric Times" (see section, page 365). 

 Here is shown a deposit of cliff rubble with the beach resting 

 upon it. 



In Guernsey I have not found rubble under the beach, but 

 that may be because our cliffs have been eroded differently ; 

 but I have found abundance of rock so worn as to suggest 

 the long continued action of pebbles which are no longer in 

 situ ; the rocks show that the beach of their time was lower 

 than the 25-ft. beach. (See Photo No. 10.) . 



