1916.] THE POST-GLACIAL ELEVATION. 39? 



that only the low lands now submerged were used by the 

 animals of that period or we would find their remains in the 

 deposits of the island. Such is not the case for our fauna 

 and even our flora are later arrivals. Not only is this 

 so but the approximate date of their advent can be fixed. 

 I need only remind you, in this connection, of Mr. J. Sinel's 

 lecture in this institution, wherein he showed the order 

 of the arrival of various animals and how some reached 

 Guernsey on the advance of a genial climate just before 

 the intervening valleys were inundated, and how some 

 others, making their way westward too late, reached Jersey 

 and Alderney; but some of the still later arrivals got to 

 Alderney and failed to reach Jersey and Guernsey. I 

 understand that Mr. Attenborough, a Jersey worker in botany, 

 has corroborated Mr. Sinel's conclusions from data obtained 

 from the flora alone. I am sorry that my plan for this paper 

 obliges me to be content with this mere mention, and to use 

 these facts as confirmatory of the statement deduced from 

 geological data that the order of the separation was as 

 described. 



We now go one step further. The Guernsey group 

 became disconnected ; the valley between Herm and Sark 

 became inundated and remained so for a very long while when 

 Herm was still attached to Guernsey. The land connecting 

 these was linked up by rock-protected islets now reduced to 

 rock platforms (flat rocks) and reefs. These kept the con- 

 nection up for so long that portions have been separated by 

 the continued rise of the sea-level during historical times. 



There is evidence, therefore, that the changes culminating 

 in the separate islands, as we know them, occupied the whole 

 period covered by the gradual rising of the sea-level and the 

 progressive inundation of the low Channel and inter-insular 

 lands. 



The question naturally arises — what geological evidence 

 does the island offer to support the assertion ? There is no 

 positive evidence but there is abundance of negative. 



Submergences during that period have not occurred. 

 Ice has not marked its presence. The fauna and flora now on 

 the islands are comparatively recent introductions or survivals 

 of the forest period. And not least important is the absence 

 of any of the indications of the human cultures which followed 

 the second boulder clay in England and on the Continent. 

 What then prevented the animals which had roamed the 

 Channel bottom from establishing themselves. The fact 

 stands out that before the final advance of the sea there must 



