♦ 

 ON THE PLANT REMAINS IN THE SCOTTISH PEAT MOSSES. 345 



nana Arctostaphylos alpina, and Empetrum nigrum, gives a decidedly Arctic aspect 

 to these basal layers and indicates much severer conditions than obtained during the 

 deposition of the peat immediately above, which is chiefly formed of Betula alba. 

 Above the Arctic beds the vegetation then gradually underwent a change, — the Salix, 

 hitherto so dominant, disappeared, and the ground became entirely covered with 

 Empetrum mixed with Eriophorum, — Arctostaphylos alpina, Spreng., still lingering on, 

 although sparingly. After some 18 inches of peat, formed almost entirely of the stems 

 of Empetrum, had been deposited, a complete change of conditions and vegetation took 

 place. The Empetrum died away and a growth of Betula alba of small size — most of 

 the stems being less than 8 inches in diameter — covered the whole district and 

 persisted until a thickness of 2 or 3 feet of Betula remains had accumulated. The 

 lower layers of the birch zone contains quantities of the seeds of Menyanihes trifoliata, 

 L., this plant having first made its appearance in the upper layers of Empetrum. 

 Above this no further Betula remains are met with, but the peat — at that time some 

 5 feet in depth— became tenanted with Eriophorum, mixed with a good deal of 

 Calluna. This wet moorland vegetation persisted until 2 feet of peat had been 

 deposited and was succeeded by a great growth of almost pure Calluna, representing 

 much drier conditions. This represents the beginning of the upper forest zone, for 

 the Calluna moor quickly became covered with Pinus sylvestris, which attained a 

 large size. 



Eeferring to the sections which have been given, it will be seen that in section 3 

 two distinct pine zones are represented, separated by 1-3 feet of Sphagnum peat. This 

 is a feature found very generally over Coire Bog and in other Highland areas and its 

 possible significance will be considered in detail in the section dealing with the Spey- 

 Findhorn watershed and in the summary and general conclusion at the end of this paper. 

 As the upper forest zone of pine passed away, the character of the peat indicates wetter 

 and possibly colder conditions, as it is formed entirely from the remains of Scirpus sp., 

 Eriophorum, and Sphagnum. A considerable period appears to have elapsed between 

 the passing away of the upper forest zone and the incoming of the present type of 

 vegetation, as quite 2 feet of Scirpus- Sphagnum-Eriophorum peat lies upon the pine 

 zone and it is not until about 1 foot below the present surface that the plants of the 

 present vegetation begin to make their appearance in abundance. 



From the evidence obtained, it seems that the peat began to grow over this area 

 soon after the ice which deposited the large moraines at about 1000 feet had retreated, 

 — first under arctic or sub-arctic conditions, merging into wet moorland conditions, 

 changing to dry forest conditions, and then relapsing to wet moorland, with a 

 gradual change to present conditions. The correlation of these successive strata 

 with those in other districts and with the later phases of the glacial period will be 

 considered in the part of the paper dealing with the Spey-Findhorn area and in the 

 general summary. 



