396 THE POST-GLACIAL ELEVATION. 



These beds offer evidences of changes in the climate as 

 they vary in their different layers. The lower layers are of 

 forest trees, but as the beds accumulate it is found that the 

 plants alter in type, affording evidence of warmer and colder, 

 drier and wetter climates. I feel that it would hardly be 

 necessary for my object to follow all these minor changes in 

 this paper, because there is nothing strictly local and the 

 details can be found in many publications such as "Submerged 

 Forests," by Clement Reid (Cambridge University Press). 

 Had I anything in this connection new and purely local I would 

 not pass over this period with such brevity, but I have not. 



There are two points I must speak of, the erosion of the 

 land connections and the lower land between the islands. I 

 have already said that sea erosion is only responsible for a 

 deepening of the already low connecting pieces which were 

 dry at the beginning at this stage ; that I think should 

 emphasize, for we too often speak of the separation of the 

 islands from the mainland as if the sea erosion had done all the 

 work. It is not so. I will call to your minds the statement 

 I made earlier in the paper that sea erosion is only active 

 when the sea-level is rising. 



While the water was gaining on the lower levels of the 

 sinking land, great changes were taking place in the relative 

 land and sea areas. At first only the margins of the island 

 groups came under the action of the eroding sea. Thus Jersey 

 was being eaten away on its west and south sides while 

 maintaining its land connection with the mainland. At this 

 stage the land connection around Alderney included Alderney 

 itself, the banks to the south of the Casquets, Burhou and all 

 the reefs around and between. 



While these groups were still connected with the mainland, 

 the Guernsey-Sark group detached itself from the land, and 

 for a relatively long period these stood out as a large area of 

 land divided from the other portions of the coast to the north, 

 south and east. I have purposely suppressed much that must 

 have happened during the interval between the rise of the 

 land of, or over 600 feet, because I have no local evidence to 

 offer, and my readers can make the necessary deductions as 

 well as I can. It will be sufficient to say that the channel 

 was at times the scene of a fertile valley, at others a arid 

 desert, according to the absence or nearness of ice. 



Then as the sea gained ground, not so much by erosion 

 as by a rise of sea-level, all this became altered and the 

 evidences of changes and of life passed away and became 

 buried under the sea. One thing seems certain, and that is 



