236 THAN S ACTIONS AND PKOCEEDINGS OF THE [Sess. lxvi, 



consists mainly of the decomposed remains of twigs, leaves, 

 and seeds — most of them too obscure to enable anyone to 

 make out anything of value regarding their botanical 

 position. Still, with patient work, long-continued, much 

 good has been done with such of the material as promised 

 good results. Long lists of plants have thus been recorded, 

 and a vast mass of data has been got together and carefully 

 studied. Then, again, where the evidence afforded by the 

 plant-remains has failed to give the information required, 

 indirect CAjidence, often of considerable value, has been 

 obtained from a study of the animal-remains associated 

 with the plants. 



In considering the subject with this material before one 

 it is necessary to constantly bear in mind the fact that 

 the physical geography of Britain, as we see it to-day, is 

 mostly quite recent in origin. There was a time, for 

 example, and not so long ago either, when Britain stood 

 much higher above the sea than it does now, and when 

 the Forth was entirely a fresh- water river, and the wide 

 space occupied to-day by the Xorth Sea was land, with 

 the Ehine flowing through the lower parts, and making 

 its way to the Atlantic by way of Shetland. This was 

 an event which may well have occurred long after man 

 first peopled these parts. So, too, with the climate. 

 Everyone is familiar with the fact that we have, as it were, 

 only lately been favoured with temperate conditions, which 

 came after a prolonged Age of Snow ; and many people 

 are further aware that before that cold period these 

 islands experienced many climatal changes of other kinds. 

 Eeflection upon these well-known facts should suffice to 

 convince anyone that our present flora is tiie net outcome 

 of a complex series of changes of environment in the 

 past. 



We may now proceed to consider some of the evidence 

 in support of this view in detail, always bearing in mind 

 in doing so the important principle that tlie present 

 physical geography of Britain dates back but a short 

 time into the past. 



If we go back to consider what the vegetation of tlie 

 Miocene Period was like, we find traces of a Mora quite 

 unlike that which prevails in Western Europe at the 



