SCOTLAND AS MAN FOUND IT 11 



But these conditions too, had undergone modification 

 before the arrival of man in Scotland, for the Fifty- Foot 

 Raised Beach, which contains the earliest records of his 

 settlements, appears to be contemporaneous with a lower 

 succession of layers in our peat-mosses, the plants in which 

 indicate a period of decreasing temperature and of increasing 

 rainfall. Bogs of sphagnum moss, over which cotton-grass 

 waved in abundance, gradually swamped the birch woods 

 and buried the decaying trees under thick layers of peat. 

 These inhospitable conditions culminated in a return of 

 snowfields to the mountain-tops and glaciers to the high 

 valleys, and the Arctic plants again crept down the mountain- 

 sides. It need not be assumed, however, that the tempera- 

 ture which welcomed man to Scotland was very much lower 

 than that of the present day, for the fact that even now 

 snow-wreaths which are little short of permanent, lie year 

 in, year out, in the corries of the higher Grampians and of 

 Ben Nevis, indicates that a small fall in temperature would 

 be enough to clothe the hill-tops once more with a permanent 

 cap of snow and to fill the upper valleys with glaciers. Con- 

 ditions so forbidding, however, did not extend to the low- 

 lands or the coastal areas where man made his first homes. 

 So far as we can judge from the seeds or leaves of plants 

 found in lowland deposits contemporaneous with the men 

 of the Later Stone Age (thanks to the researches of James 

 Bennie and Clement Reid), a rich flora, very similar to that 

 of the present day overspread the valleys. The meadows 

 were covered with lush grass, chequered by the blossoms 

 of buttercups, of spear-thistles, dandelions and sow-thistles, 

 of the yellow ox-eye, scentless mayweed, the hemp-nettle 

 and St John's wort; on dry banks, coltsfoot, tormentil and 

 chickweed flourished ; in, or near by running water grew 

 the water buttercup and water blinks, mare's tail and water 

 milfoil ; by riversides blossomed valerian, meadow-sweet and 

 the red campion; the thickets were starred by the wood- 

 sorrel ; the bugle, dog's mercury and dock flourished in the 

 shade; the raspberry and bramble vied for a place with the 

 wild rose ; and the marshy places were enlivened with a 

 wealth of flower and foliage, from the showy ragged robin, 

 lousewort, buck bean and marsh marigold to the lesser 

 spearwort and marsh violet, pondweeds, rushes and sedges. 



