2 Origin of the British Flora. 



fauna and flora, and the relations these bear to the climatic 

 changes through which this country has passed. 



Moreover, this life spent principally in field, and moor, 

 and forest has forced me to observe how each changing 

 season is marked by corresponding adaptations in the 

 animals and plants, such as enable the species to preserve 

 themselves, to multiply, and to spread ; or, if adaptation 

 fails at any point, through some climatic irregularity, how 

 sweeping and rapid may be the extermination of all except 

 some few accidentally favoured individuals. While col- 

 lecting seeds and fruits for comparison with the fossils 

 I was compelled particularly to observe their many 

 adaptations for dispersal, and also their times of ripening, 

 and the abundance or scarcity of ripe seeds. 



It was impossible under such circumstances to avoid 

 seeing the close connexion which must exist between the 

 present geographical distribution of plants and animals 

 and bygone changes in climate and in physical geography. 

 Edward Forbes' * essay was read and read again ; but it 

 soon became apparent that his brilliant generalisations, 

 though far in advance of the date when they were written, 

 were only partially true. Much of his reasoning was 

 fallacious. 



To explain the presence of Arctic and of Iberian plants 

 in Britain, he showed that outliers of the Arctic flora stranded 

 on our mountain peaks could be accounted for by an 

 appeal to the climatic conditions of former days, when a 

 similar flora covered the whole of our Islands, and was not 

 confined to isolated mountains. He did not see, apparently, 

 that the use of this reasoning precluded the use of the 



* ' On the Connexion between the Distribution of the existing 

 Fauna and Flora of the British Isles, and the Geological Changes 

 which have affected their area, especially during the epoch of the 

 Northern Drift.' — Mem. Geo/. Survey, Vol. I., pp. 336-432 (1846). 



