808 MR FRANCIS J. LEWIS 



willows which so frequently occur in the peat are not at present found within 200 feet 

 above sea-level in the latitude of Shetland. Salix herbacea still occurs in the 

 islands — in small isolated patches on the Weisdale hills at an elevation of about 800 

 feet, and in Foula on the Sneug and Brustins, at 1000 feet. This is the lowest altitude 

 recorded for this plant in Britain. In Ireland it is found at 870 feet in Donegal (6). 

 In Scotland it only occurs on summits which rise about 2000 feet. 



The Lower Forest Stratum in Shetland. — The vegetation of this stratum repre- 

 sents a complete change from that of the first arctic bed, and presents one of the most 

 striking features of the Shetland peat. Large trees of Betula verrucosa Ehrh., Alnus 

 glutinosa, Pyrus Aucuparia are found even in the most exposed situations, where it is 

 impossible to grow trees at the present day even with careful artificial shelter. The 

 remains of this forest are found on the exposed sides of Sandness Hill up to 700 feet; 

 Dale Hill. Blouk Field, and Watsness, quite near the cliffs of the west coast ; to near the 

 summits of the hills in the centre of the Mainland, and even in the island of Foula 

 These trees do not represent copses growing in sheltered valleys away from the coast, 

 but appear in every district hitherto visited, and are just as well developed in the most 

 exposed situations as in the valleys. The unsuccessful efforts to grow small copses in 

 sheltered positions, aided by the most effective artificial protection, is sufficient to show 

 the present unsuitability of the Shetland climate for tree growth ; and the fact that the 

 buried forest occurs on high ground within a few hundred yards of the west coast, where 

 the vegetation growing on peat is frequently rolled back like a carpet by the force of 

 winter gales, is sufficient to show that the meteorological conditions during the Lower 

 Forest period were not the same as those of the present day. 



Some discussion has arisen lately on the position of tree remains in peat. Gunnar 

 Andersson (7) in a recent paper brings forward some evidence to show that such re- 

 mains in Scandinavia are not always confined to one level, but may occur scattered 

 throughout the thickness of the peat. Special attention was paid to this point whilst 

 the buried forest in Shetland was being examined, and the result is given on pages 816- 

 817 of this paper. It may be said here that all the timber was confined to a definite 

 layer 2 feet thick near the base of the peat. 



Although a considerable amount of the material has been looked through in the 

 field and 7 lbs. of the peat has been analysed in the laboratory, no arctic plants have 

 been found. The list given on page 801 represents the plants found up to the present, 

 iind they are quite representative of a marshy wood with occasional drier spots. Carex 

 paniculata is present in great abundance, although it is not now found in Shetland. 



The most important features are given below : — 



1 . Some of the plants had a more northerly distribution than at the present time. 



2. There are no arctic or alpine plants. 



3. The plants are all such as might commonly occur in a swampy deciduous wood 

 in the lowlands of any part of Southern Great Britain at the present time. 



4. The size and position of the trees suggest that Shetland must have been under 



