ON" THE PLANT REMAINS IN THE SCOTTISH PEAT MOSSES. 357 



with those described by workers in Scandinavia and Germany, but some points of 

 resemblance may be briefly indicated. 



In Western Norway the peat shows considerable resemblance to that described in 

 Kirkcudbrightshire (2). According to Blyth (7), two forest-beds can be distinguished, 

 — an upper, consisting chiefly of Pinus sylvestris, and a lower, of Quercus with Corylus 

 Avellana. These two forest-beds are separated by about 6 feet of peat in a much 

 compressed condition. The chief difference here is the dominance of birch in the lower 

 forest-bed of Scotland and of the oak in that of Norway. In both cases, however, we have 

 a lower and upper forest-bed, separated by moorland and swamp peat of considerable 

 thickness. 



Gunnar Andersson (6) has traced out the history of the peat in Southern Sweden 

 in a very complete manner and finds that an Arctic flora is nearly always present at 

 the base, consisting of such plants as Dryas octopetala, Salix polaris, S. herbacea, S. 

 reticulata, Oxyria Digyna, Arctostaphylos alpina, etc. After this a definite succession 

 of forest-beds can be made out, — first birch, then in succession spruce, oak, and pine. 

 This peat is post-glacial in the sense that it was laid down after the disappearance of 

 the Great Baltic glacier and appears to have originated about the same time as the 

 Yoldia clays of the Baltic area. According to the geological evidence, the great Baltic 

 glacier appears to have been contemporaneous with the district ice-sheets and mountain- 

 valley glaciers of Scotland, as pointed out by Geikie (8). If that is so, the birch forest 

 of Southern Sweden would be contemporaneous with the lower buried forest of the 

 Southern Uplands, the Arctic flora below this being missing in the Scottish areas. At 

 the same time the evidence of the Scottish areas of a later return to cold conditions is 

 apparently wanting in Southern Sweden, for no Arctic plants are mentioned by Gunnar 

 Andersson as occurring above the birch forest remains. But the complete correlation 

 of the British peat strata with those occurring on the Continent is a task which is hardly 

 possible with the amount of evidence that is at present available, and much further 

 work requires to be done before the comparison can be made with safety. It only 

 remains to point out the great similarity which exists between the basal Arctic beds in 

 the Scottish Highlands and those in Scandinavia. Dryas appears to have been more 

 abundant in the Scandinavian areas, but in both countries we find Arctic willows 

 predominating in the basal peat layers with such plants as Arctostaphylos alpina, 

 Betula nana, L., and Empetrum nigrum, L. Nathorst (9) has described such an Arctic 

 flora as represented in many districts in Norway, Gunnar Andersson (6) describes the 

 same from Southern Sweden, and Steenstrup (10) has given many instances where such 

 plants form a distinct zone in the fresh- water clays underlying the oldest peat mosses 

 in Denmark. Indeed, such deposits have been described not only from Scandinavia, 

 but also from Russia and Northern Germany. Reference might also be made to the 

 interesting paper by Wille (ll), giving an account of the changes in distribution of an 

 Arctic flora in Norway, and to another by the same author (12) dealing with the 

 distribution of Dryas octopetala in post-glacial times. 



