PHYSICAL CONDITIONS— POSTGLACIAL. 513 



Scandinavian type of vegetation is so poorly represented in the 

 Hibernian flora. The climate, we may suppose, was already 

 becoming milder, and the high -alpine forms were gradually 

 vanishing from the low grounds, so that only a few of these 

 could make their way south into Ireland. 



A very general elevation of the land characterised the next 

 stage of the postglacial period, and it is not difficult to follow 

 the gradual improvement from arctic to temperate conditions. 

 It was precisely such a change as we should now experience 

 were we to start from the American shores of the Arctic Ocean, 

 and, after traversing the Barren Grounds and the region of coni- 

 fers, to enter upon the zone of deciduous trees. "We see the 

 British Islands at first surrounded by cold waters in which 

 floating-ice abounds. Our mountain-valleys support consider- 

 able glaciers, and the winter temperature is severe. A scanty 

 arctic and alpine flora of lichens and mosses and dwarf birch, 

 with other northern forms, is sprinkled over the low grounds, 

 and the reindeer is the most notable denizen of the land. At 

 this time England is connected with the Continent, probably 

 with Belgium and the north-east of France, but in Scotland the 

 low-lying maritime districts are still to some extent under water. 

 Ireland forms, as it does now, a separate island. The sea, how- 

 ever, is slowly retreating, and the cold of winter becoming less 

 severe, and with the improvement of the climate plants and ani- 

 mals of more temperate types begin to appear in the south of 

 England. Eventually all our islands are united, while at the 

 same time a broad plain extends over the area of the North Sea, 

 and connects Britain with Holland and Denmark. Before the 

 great forest- vegetation had covered our country, the land, accord- 

 ing to Forbes, would be in the condition of the Barren Grounds, 

 bare and treeless, with the reindeer, the Irish elk, the urus, and 

 species of bear, fox, wolf, hare, cat, and beaver, for its inhabitants. 

 Vast herds of the Irish elk or deer then roamed over Ireland 

 and what is now the basin of the Irish Sea and the Isle of Man, 

 but they do not appear to have entered Scotland in any force ; 

 at all events, no trace of them as a rule is met with in the post- 



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