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by Van der Sleen. For afterwards came the ice-age, 

 which of course entirely expelled the original tertiary flora 

 from the south part of England, which was the only part 

 left uncovered by the ice. Many articles hâve been written 

 already about the flora, which existed south of the ice- 

 border at that time. Much dépends hère upon the question, 

 whether a sea- or a land-chmate prevailed. In the south 

 of England and in our country the climatic snow-line was 

 situated, according to Penck and Briickner, at an 

 altitude of about 800 meters. In the case of a sea-climate 

 having prevailed, it is possible that there still existed a 

 fairly rich flora. With a pronounced sea-climate, the tree- 

 limit may even surpass the snow-line, as I hâve been 

 able to see myself in the région of Mt. Rainier in the 

 United States, whilst it usually remains more than 800 

 meters below it. As a rule, however, the climate is consi- 

 dered to hâve been rather continental. The big ice-deposits 

 must hâve caused an area of high pressure and a preva- 

 lence of eastern winds on the southside of the ice-border. 

 But in this case the flora can not possibly hâve been 

 much more than a tundra-flora, very poor in species. The 

 well-known peat-soil explorer Weber, in absolute con- 

 forraity with this, found in peat-soil of the ice-age only 

 remainders of a few species of mosses and Carex. We 

 may conciude, that practically the whoîe actual British 

 flora must hâve corne into England after the ice-age, and 

 this chiefly from the south-east. And in connection here- 

 with we can only ask, whether there is a possibility of 

 the Rhine having flowed through a certain portion of 

 England even after the ice-age, and further, whether there 

 may exist in England species of plants, the présence of 

 which can only be accounted for by this circumstance. 



The first part of this question may be answered in the 

 affirmative. It seems to be considered a fact, that the North 

 Sea during the ice-age was dry up to a point far north. 



