12 INTRODUCTORY 



Before man had spent many centuries in our northern 

 land, the cold disappeared as unaccountably as it had come, 

 the snownelds melted, the land rose from the waves, and, as 

 if to make amends for its former rigour, the climate so 

 ameliorated that forests of Scots fir spread over the drying 

 peat-bogs and extended to an altitude of close on 3500 feet 

 up the mountain-sides, where, in our own day, 2000 feet 

 marks the upward limit of forest growth. 



ANIMAL LIFE 



What were the creatures which the first inhabitants of 

 Scotland found installed in its glades and forests ? For an 

 answer we have to enquire of the relics which have been 

 cherished for thousands of years in the depths of the marine 

 clays, of the fresh-water marls and peat-bogs which were 

 contemporaneous with or preceded by a short space the 

 coming of man, or even of the food refuse which man him- 

 self cast carelessly aside all unthinking that it would reveal 

 to his distant successors the animals he encountered and 

 overcame. The dregs of these deposits reveal a strange 

 mixture of animal types. 



The native inhabitants of Scotland, with the exception 

 of the mobile forms, such as birds, had reached Britain from 

 the continental areas while the English Channel and a part 

 of the North Sea were dry valleys in the western extension 

 of Europe. The rigours of the Ice Age and its inhospitable 

 glaciers had cleared the land of the preglacial fauna, but as 

 the ice disappeared the cold climate of the later phases of 

 the Great Ice Age attracted an Arctic fauna, which retreated 

 northwards as vegetation sprang up on the heels of the 

 shrinking glaciers. The grassy plains which superseded the 

 Arctic vegetation of the great flats of clay and hillocks of 

 gravel deposited by the ice-fields, led another series of animals, 

 creatures of the plains, to make the northward pilgrimage. 

 While the forest conditions, which, as we have seen, pre- 

 ceded the first peat period and covered the land even up 

 to a height of 1 500 feet above sea-level, enticed still another 

 series, of woodland forms, there to make their homes. 



Under the conditions prevailing in a continental area 

 where the change of climate is gradual, these three types of 



