PLANT REMAINS IN PEAT MOSSES 321 



Reid. The lower beds rest directly upon the boulder clay, and 

 contain Sa/ix herbacea, S. po/aris, S. reticulata, together with 

 about twenty other plants, some of which certainly do not now 

 occur in the same regions as the arctic willows. As the basal 

 arctic bed occurs in a lacustrine deposit, it is perhaps possible 

 that it contains fossils from slightly different periods. Be that 

 as it may, it is certain that the arctic willows indicate a very 

 different type of flora from the temperate bed above containing 

 such temperate forms as Sambitcus nigra, Primus spinosa, 

 P. Padus, Rubus Idarns, Crataegus oxyacantha. These plants 

 occur mixed with others usually considered as weeds of cultiva- 

 tion, such as Stellaria media, ALthusa cynapium, Lapsana communis, 

 which suggest that the temperate bed belongs to a comparatively 

 late period. If there is no break in continuity between the basal 

 arctic bed and the overlying deposits containing temperate 

 plants and weeds of cultivation, the evidence tends to show that 

 the arctic plants belong to a period much more recent than the 

 retreat of the ice-sheet. 



Similar arctic plant beds have been described from Cor- 

 storphine, Faskine (9), Dronachy (10), by Bennie, and from 

 Crianlarich by Reid (n), the plants from the various sections 

 having been determined by Mr. Clement Reid. 



Numerous other examples might be quoted from the lists 

 given by Mr. Clement Reid (11), but enough has been said to 

 show that arctic plant beds are of wide occurrence in Britain. 

 The arctic plants of Hailes, Corstorphine, Dronachy, and 

 Crianlarich apparently belong to the same stage, and the 

 presence of Salix polaris in those deposits in the lowlands of 

 Scotland suggests that they can hardly be younger than the first 

 arctic bed underlying the Lower Forest in the peat mosses. 



The section at Hoxne, where an arctic bed overlies a deposit 

 containing temperate plants, gives the same sequence as the 

 south of Scotland and Shetland peat, where the Lower Forest 

 is overlaid by an arctic zone, though the fact that the Hoxne 

 deposits rest upon the chalky boulder clay and the southern 

 upland mosses upon morainic material of a later stage makes 

 it probable that the Hoxne temperate bed is older than the 

 Lower Forestian. If that be so, the arctic bed at Hoxne 

 might still be contemporaneous with the first arctic bed of 

 the peat mosses. 



There can be little doubt that the lower bed at Hoxne 



