22 COLIN CLOUT'S CALENDAR. 



Clearly it would be absurd to set down so many coin- 

 cidences between these warm western regions of Britain 

 and the Continent to the chapter of accidents alone. 

 Our south-western flora is undoubtedly on the whole a 

 Spanish and Pyrenean flora in its general aspect, with a 

 large intermixture of northern forms. Sometimes the 

 south European species linger on only in a single spot, 

 like the hairy spurge at Claverton Down and the purple 

 lobelia at Axminster ; sometimes they spread over wide 

 areas, and hold their own manfully against the intrusive 

 Scandinavian types. Of these curious phenomena the 

 probable explanation is suggested in a passing hint by 

 Mr. Wallace. 



The southern plants are probably relics of the flora 

 which lived in Britain before the glacial epoch. At that 

 time, as our geologists are agreed in believing, Great 

 Britain and Ireland formed part of the continent of 

 Europe, to which they were united by a broad belt of 

 land, extending over the present bed of the English 

 Channel and the Bay of Biscay. As the ice pushed its 

 way southward, the northern plants migrated before it to 

 regions which were made more fit for them by the 

 change of climate due to the glaciating conditions. 

 Thus the arbutus, the Mediterranean heath, the various 

 warm types of saxifrages, of butterwort, and of spurge, 

 must have had a range from Killarney and Cornwall to 

 the Pyrenees, the Apennines, and Crete. It is notice- 

 able, too, that, according to the map recently published 

 by Dr. Geikie, the south-west of Ireland and England are 

 just the parts of Britain which escaped glaciation during 

 the height of the great ice age. 



Yery possibly, however, these warmer plants may at 

 first have been driven quite southward, beyond the exist- 

 ing limits of Britain, but may afterward have moved 



