ON THE PLANT REMAINS IN THE SCOTTISH PEAT MOSSES. 



63 



The Lower Peat Bog— This zone is present in the low-lying Wigtownshire mosses 

 and the other areas examined in the Southern Uplands, in Skye, the Outer Hebrides, 

 and in the Shetlands. In the Southern Upland areas and the Shetlands it exhibits the 

 greatest uniformity, the bulk of the peat being formed from the remains of Sphagnum, 

 Scirpus csespitosus, Eriophorum vaginatum, E. angustifolium, Molinia cserulea, Carices. 

 Calluna is scarce or absent, and the peat areas at this time seem to have formed extremely 

 wet Scirpus and Sphagnum moors, and. trees appear to have been entirely absent. The 

 peat bears every sign of having been formed under conditions eminently favourable for 

 peat growth, and although this zone frequently attains a thickness of 5 to 7 feet it is 



1 ss 



c« 



££ 



^%i 



Sphagnum 



Pinus Eriophorum 



sylvestris and 



Calluna 



Betula 

 nana 



Empetrum Salix 

 reticulata 



Fig. 4. — Showing the replacement of the older beds of peat by fresh-water sands and gravels at sharp bends along stream-sides. 



1400 feet on the Abhuinn-a-Coire-Bhuig, Easter Ross. 



probable that it was formed in less time than the First Arctic Bed, which is only 18 

 inches in average thickness. 



In the low-lying districts of Wigtownshire, Skye, and the Uist a different type of flora 

 overspread the peat during this stage, for the Lower Peat Bog there consists of the re- 

 mains of Phragmites communis, Equisetum sps., Menyanthes trifoliata. In fact, these 

 areas must have been covered with a series of shallow lakes and swamps, possibly explained 

 by the fact that the peat rests upon stiff clays, whilst many of the Southern Upland 

 mosses rest upon sand and gravels. In Lewis, the Lower Peat Bog approximates more 

 to the Southern Upland type, being composed of Sphagnum, Eriophorum angustifolium, 

 Erica Tetralix. 



A noticeable feature is the fact that the Lower Peat Bog tends to thin out as it is 

 traced across Scotland from the south to the north. This is a phenomenon of some 

 interest, particularly when considered in connection with the significance of the succession 



