Il6 HISTORY OF THE EUROPEAN FAUNA. 



it must have come to us at such an epoch. It at once 

 suggests some shady waterfall in a tropical forest, and 

 indeed the home of the genus is South America. It 

 is one of those plants which have evidently migrated 

 to us from South-western Europe, 'a mere remnant 

 of a once luxuriant flora. 



Sir Archibald Geikie tells us (p. 837), and in the 

 main every one agrees with him, that at the beginning 

 of the Tertiary era in which we now live, the climate 

 was of a tropical and subtropical character in Europe. 

 Gradually it became more temperate, and eventually 

 it passed into a phase of extreme cold, but since that 

 time the cold has again gradually diminished. It is 

 quite evident, therefore, that from a purely geological 

 point of view our south-western flora must have 

 migrated northward before the cold came on, and 

 survived in sheltered localities under the influence 

 of the mild coast climate. Some, however, suppose 

 that there occurred a phase of extreme mildness im- 

 mediately after the Glacial period, and that it was 

 during that time that the Lusitanian fauna and flora 

 became established in the British Islands. To this 

 Professor James Geikie replies (, p. 169), "there are few 

 points we can be more sure of than this, that since 

 the close of the Glacial epoch since the deposition of 

 the clays with Arctic shells and the Saxicava sands 

 there have been no great oscillations, but only a 

 gradual amelioration of climate. It is quite impossible 

 to believe that any warm period could have intervened 

 between the last Arctic and the present temperate 



