io INTRODUCTORY 



wave action during what must have been an extended 

 period of time, the old shore is represented in the midlands 

 by the Carse lands of the Forth valley, a fertile plain more 

 than three miles wide above Stirling, and extending as far 

 as Gartmore, some 1 7 miles beyond that town, and on the 

 Clyde by level terraces which can be traced beyond Dalmuir 

 on the north and Paisley on the south. 



To the first-comers the inland landmarks of Scotland must 

 have appeared almost as they are to-day. The hills and 

 valleys had already been carved into their present aspect. 

 True, the rivers were swollen in volume and many of the 

 lakes, ponded back by the debris of the old glaciers, were 

 greater than now, while many low-lying areas, now fertile 

 plains, were bogs and marshy flats ; but the ice-fields of 

 the Great Glaciation had disappeared, although a recru- 

 descence of colder conditions had again clad the mountain- 

 tops in snow and filled the higher valleys with moving 

 sheets of ice. 



CLIMATE AND VEGETATION 



The period during which the Fifty- Foot terrace was 

 being carved out or levelled up by the sea was a prolonged 

 one, and in it Scotland underwent drastic changes of 

 climate. At exactly what stage in the formation of the 

 Fifty-Foot Beach man appeared upon our shores, it is im- 

 possible to say, but it is certain that the conditions which 

 immediately followed the retreat of the great ice-sheet had 

 long passed away. The Arctic climate had gradually been 

 replaced by one at least as temperate as that of to-day; 

 distinctive Arctic plants, such as Arctic Willows (Salix 

 repens and polaris], Arctic Birch (Betula nana), Crow- 

 berry (Empetrum nigriim], Creeping Azalea (Loiseleuria 

 recumbens], and Mountain Avens (Dryas octopetala], all 

 of which occurred in late glacial times on low ground at 

 Corstorphine in the neighbourhood of Edinburgh, had 

 deserted the lowland valleys and followed the line of the 

 dwindling snowfields to the hill-tops. With the rising 

 temperature, forests of Silver Birch, Hazel and Alder clad 

 the lowlands and spread up the mountain-sides, at least to 

 an elevation of over 1 500 feet above sea-level. 



