44 



MR FRANCIS J. LEWIS 



broad, well-drained valleys. This expectation was fully borne out, but such differences 

 were chiefly confined to the lower layers of peat. The upper forest is present over all 

 the area examined and forms an excellent datum line (Plate IV. fig. 11). Sections taken 

 to the S.E. of Loch Lydoch showed the following beds : — 



Characteristic Plants. 



1. Scirpus csespitosus. 



2. Pmus sylvestris. 



3. Sphagnum. 



i. Betula alba (shrubby growth). 



5. Structureless peat containing traces of Sphagnum. 



Accompanying Plants. 



1. Sphagnum. 



2. Calluna vulgaris. 



V actinium Myrtillus. 



3. Betula alba twigs. 



4. Eriophorum vaginatum. Sphagnum. 



Granitic saud and gravel. 



Between Loch Lydoch and the Black Corries the lower layers of the peat show a 

 different vegetation : — 



Characteristic Plants. 



1. Sphagnum. 



2. Pinus sylvestris. 



2. Mossy peat with much Phragmites communis. 

 4. Betula nana. 



Accompanying Plants. 



1. Scirpus csespitosus. 



2. Calluna vulgaris. 

 3. 



4. Sphagnum, Equisetum sp. 

 Potentilla Comarum. 



Further west, towards Kingshouse, the general sequence remains the same, but the 

 basal beds yield a few other plants. 



Characteristic Plants. 



Scirpus csespitosus. 

 Pinus sylvestris. 

 Scirpus csespitosus. 

 Grimmia sp. 

 Betula nana. 



6. Equisetum, Sphagnum. 

 7. 



Accompanying Plants. 



1. Sphagnum, Eriophorum vaginatum. 



2. Calluna vulgaris. 



3. Sphagnum, Eriophorum. 

 4. 



5. Salix Arbuscula, Empetrum nigrum, Arcio- 

 staphylos alpina. 



6. Many broken and water-worn fragments of Betula 

 alba. 



Sand and clay, with angular stones. 



It is evident from the plant remains that much of the moor of Rannoch peat began to 

 form under marsh conditions. Quantities of water-worn birch fragments occur towards 

 Kingshouse, not only with the marsh plants at the base of the peat, but in the drift 

 below. The wood bears traces of prolonged water action, and although many of the 

 fragments are small twigs, some are larger and evidently belong to fairly large trunks 

 of birch mixed with fragments of birch bark. This wood evidently did not grow 

 in situ, and it can hardly represent the drift of a few streams, as the material occurs in 

 many sections spread over a large area. At the same time, this drift-wood cannot 

 represent debris from the upper forest, as that is a well-marked zone in the higher 

 layers of peat and separated from the drift-wood under discussion by strata-containing 

 arctic plants. The character and position of this material certainly suggests derivation 

 from older beds which existed here before the present peat mosses began to form. 



