ScHARFF— 0;j the Origin of the JEuropean Fauna. 493 



Tcry seriously. But it is more likely that these plants lived where 

 their remains are now foimcl, especially since there can be no doubt at 

 iill that some Arctic species grew formerly in the south of England. 

 The exception, above referred to by Prof. ISTathorst — namely, of 

 a locality where deposits of Arctic plants occur not within the limits 

 of the former range of glaciers — is that of Bovey Tracey in Devon- 

 shire. Though the age of this deposit in not quite settled, it does 

 not matter very much. The fact remains, that Arctic plants did here 

 flourish some time or other within a recent geological epoch, and do not 

 do so now. Prof J. Geikie (35 a, p. 398) remarks, " during the climax 

 of Glacial cold, it is unlikely that Southern England had much, if any, 

 vegetation to boast of." "It is certain, however, that it was clothed 

 and peopled by an Arctic flora and fauna when the climatic condi- 

 tions were somewhat less severe, relics of that flora having been, 

 detected at Bovey Tracey." 



The Arctic plants that have been discovered there comprise Betula 

 nana and^. alha, Salix cinera and Arctostafhylos uva-ursi. iN'ow three 

 of these four species are still natives in the British Islands and all are 

 forms which probably came to us with the Arctic migration which I 

 described. They travelled south with the reindeer and other Mam- 

 mals, and probably covered tracts of country from which, with the 

 increased struggle for existence later on, they have again been evicted 

 by stronger rivals. But a discovery of their remains does not neces- 

 sarily indicate that a great change of climate has taken place. Indeed 

 when we carefully examine the present range of Arctic plants in the 

 British Islands, a curious fact presents itself which no doubt has been 

 fre(]Xiently noted by botanists, viz. that some of the most characteristi- 

 cally Arctic species and some which are often quoted by glacialists in 

 support of their theories of the former presence of an Arctic climate in 

 the British Islands — flourish at the i)i'esent moment in very mild 

 situations. I need only remind those interested in the history of the 

 Glacial Period that the Mountain Avens {JDryas octoiJetala) abounds in 

 the west of Ireland (Co. Galway), down to sea level. iN'ow it is well 

 known that the mean winter temperature of that part of Ireland 

 resembles that of Southern Europe, being no less than 12° E. above 

 freezing point. Alpine plants when cultivated in Irish gardens seem 

 as a rule to thrive exceedingly well. It would be rash therefore to 

 argue, from the occurrence of Arctic or Alpine species of plants in any 

 deposit, that the locality must have passed through an Arctic climate. 

 Indeed Dr. Thiselton-Dyer has shown that for the most part Alpine 

 plants are intolerant of very low temperature (84, p. 581), and that 



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