5o 4 PREHISTORIC EUROPE. 



which mantled them at the very climax of glacial cold, when 

 the European ice had its greatest extension. Not only were 

 the Scandinavian and Scottish ice-sheets coalescent, but they 

 overflowed the Orkney and Shetland Islands, and the Outer 

 Hebrides were buried in ice to as great a depth as they seem to 

 have been at any previous stage of the Glacial Period. How far 

 west the mer de glace extended seawards can, of course, only be 

 conjectured, but it is most probable that it reached, at least, to 

 what is now the 100-fathom line. Mr. Helland and I found 

 that the Fasroe Islands had been in like manner enveloped in 

 glacier-ice. They supported an ice-sheet of their own, the upper 

 surface of which rose to a height in the northern islands of 1600 

 feet, and in Suderoe of 1400 feet above what is now the sea- 

 level. Not only so, but the ice was so thick that it filled up all 

 the fiords and sounds between the various islands of the archi- 

 pelago, thus forming one compact mer de glace which flowed 

 outwards in all directions from the dominant points, and dis- 

 charged its icebergs into the surrounding ocean. If such were 

 the state of the Fasroe Islands in the concluding cold period of 

 the Ice Age, it is but reasonable to infer that similar extensive 

 ice-sheets flowed outwards from Iceland, Greenland, and Spitz- 

 bergen, into the Arctic Ocean, the temperature of which must 

 have been depressed to a very low degree by icebergs and floe- 

 ice, which, indeed, must have well-nigh choked it up. Is it 

 possible that any one of the southern species which occur in the 

 postglacial beds and present seas of Scandinavia could have 

 survived such conditions ? The answer, I think, must be in the 

 negative. 



Thus we seem driven to the conclusion that the visitors from 

 southern waters which are now living in the northern seas, and 

 which were at one time more plentiful, both as regards species 

 and individuals, must have immigrated long after the severity of 

 the latest glacial epoch had passed away. Their history is 

 entirely postglacial. During the deposition of the postglacial 

 shell-beds the sea was gradually retreating, and this continued 

 until the land attained a considerably wider area than it now 



