ON THE PLANT REMAINS IN THE SCOTTISH PEAT MOSSES. 



53 



tion of many miles of this bed in the Sandness- Walls region I have no hesitation in 

 saying that it marks a period of denudation during which the surface of the bed 

 became wasted and channelled into peat-hags like those met with on the present surface 

 of the peat. 



After this, the plant remains show that the peat has formed uninterruptedly under 

 moorland or peat bog conditions down to the present time. Some of the sections taken 

 in the Burn of Dale showed minor variations from the sequence just described. In 

 places the birch forest rests on the glacial deposits without any arctic plants below, 

 thus giving the same general sequence as the Southern Uplands. It is interesting to 

 note that in such cases the birch is larger than where it is underlaid by peat, conditions 

 having been more favourable for growth on the glacial clays and sands than on the peat. 



Other sections show that the intercalated arctic plants are not always present, as, in 

 one or two sections, Eriophorum and Empetrum occur at this horizon instead of dwarf 

 willow. 



Two sections taken at the bottom of the dale and close by the burn showed the 

 following sequence : — 



Characteristic Plants. 



1. Scirpus caexpitosus. 



2. Ccdluna vulgaris. 



3. Diatomaceous earth. 



4. Betula nana. 



5. Betula alba. 



6. Diatomaceous earth. 



7. Salix herbacea. 



S. herbacea x Lapponum (?) 

 S. reticulata. 



8. Potamogeton pectinatus. 



Accompanying Plants. 



1. 



2. Eriophorum vaginatum. 



3. 



4. Empetrum nigrum. 



5. 



6. 



7. Betula nana. 



8. Carex ampullacea, Menyanthes trifoliata, Ranun- 

 culus repens, Equisetum sp., Viola palustris. 



Whilst the three horizons are still well represented here (beds 7, 5, 4), a band of 

 diatomaceous earth occurs above each arctic bed. 



During the formation of this earth the place must have been occupied by a small 

 lake, and it is interesting to notice that when this was the case, peat-bog plants were 

 dominant elsewhere — as beds of Eriophorum and Sphagnum occur at this level in other 

 sections. 



A number of sections were taken round the north and south sides of Stourborough 

 Hill and Sandness Hill. In these sections the intercalated arctic bed was even better 

 developed than in the floor of the Burn of Dale, but the basal arctic bed was generally 

 absent, and the lower forest rested directly upon glacial deposits on the Old Red 

 Sandstone. 



Sections taken farther west on Simli Field and Blonk Field showed that the lower 

 forest stretched almost up to the edge of the cliffs, 200 or 300 feet above sea-level. 

 Such a discovery is certainly surprising, as trees will not grow even in the most 

 sheltered positions at the present time. In fact, it is even more surprising to find the 



