484 MR. G. ERDTMAN: STUDIES IN THE 
Analyses :— 
Sample 1 (25 em. below the surface): Alnus 13 per cent., Betula 80 per 
cent., {lex 1*4 per cent., Pinus 5'6 per cent. ; Corylus 15°8 per cent. ; 
also 10 ef. Salix pollen, 4 spores of Polypodium vulgare, spores 
of Tilletia Sphagni, ete. 
Sample 2 (45 em. below the surface) : Alnus 18 per cent., Betula 74 per 
cont., Quercus 4 per cent. ; Corylus 16 per cent. ; Utricularia pollen, 
Polypodium and Tilletia spores. 
Sample 3 (82 em. below the surface) : only 16 Betula pollen counted. 
The PF is greatest in sample 1 (25), least in sample 3 (8). 
It is probable that this moss is of a considerable age. The percentage 
figures, especially those of alder and hazel, are in favour of the view that 
the A-zone is contemporaneous with a part of it. If this view is the true 
one, there cannot have been any rise of land after the Lower Turbarian 
period, because of the fact, already mentioned, that the moss is situated 
only about 3 feet above high-water mark. Further, it seems probable that 
trees or forests once grew in Westray, and that the formation of peat in the 
moss investigated ceased long ago. 
F. Peat Mosses on the Shetland Islands. 
(Map used: Bartholomew's “ Half-inch to the mile " map of Scotland, Sheet 29.) 
Before dealing with my own investigations, a brief summary of some of 
Prof. Lewis’s results will be given. According to him the peat appears to be 
rapidly wasting away over the whole of the mainland : this is particularly 
marked on the hills in the Wall-Sandness region. The general sequence 
found over this area is as follows (Lewis, Part IT. 1906, p. 50) :— 
1. Scirpus cæspitosus ; also Sphagnum and Calluna (scarce). 
2. Eriophorum vaginatum. 
3. Dense light-coloured structureless peat crowded with the stems of 
Calluna. 
4. Salie Arbuscula ; also Empetrum nigrum, Betula nana, Erica Tetralia. 
5. Betula alba; Corylus. 
6. Sphagnum and Eriophorum vaginatum. 
T. Salix reticulata, S. herbacea : Betula nana. ` 
8. Potamogeton pectinatus; Menyanthes trifoliata, Viola palustris, 
Ranunculus repens, Equisetum sp. . 
Sand and rock. 
Lewis is doubtful whether the aquatic vegetation at the base belongs to the 
sume stage as the Arctic plants immediately overlying it. The aquatic species, 
however, were only found in a few sections, which renders it probable that 
they represent small marshy pools which were scattered over the tundra, 
and therefore actually contemporaneous with the lower layers of creeping 
