TERRESTRIAL BOGS 505 



3. Eriophorum vaginatiim peat very little moldered, Sphagnum 

 rare, Empetrum stems numerous — few small birch twigs. 

 Stones of Empetrum, numerous achenes of Potentilla 

 comarum, etc., also pollen of birch, pine, etc., and spores 

 and leaves of Sphagnum and brown fungus hyphas 20 cm. 



2. Forest peat, rather rich in humus, hard and firm. Fine 

 material consists chiefly of wood detritus. In the peat 

 are numerous trunks and twigs of birch — no coal — wash- 

 ing gave achenes of Potentilla comarum, seeds of Viola and 

 numerous fruits of different Carex species. No determin- 

 able microorganisms 45 cm. 



Total peat 240 cm. 



I. Moraine with large stones 



The two forest beds (2 and 5) appear to be of wide extent over 

 the Scottish uplands, the peat layers between varying in thickness 

 and to some extent in composition. The lowest bed always consists 

 of the remains of a birch forest. The dividing peat generally con- 

 tains arctic plants. 



In the Grampians, Carex peat (150 cm.) rests directly upon the 

 boulder clay, or sometimes has a stratum of Sphagnum peat at the 

 base. Scirpiis cccspitosiis peat or Erioplionim vcu/iiiafitiii peat fol- 

 lows this. 



In the northwest Highlands of Scotland similar sticcessions are 

 met with. In Coire Bog, in Easter Ross, the following section oc- 

 curs (Lewis quoted by Samuelson-40) : 



Dominant Plant Accompanying Plant 



1 . Scirpus — Sphagnum 3 ft. 



2. Pinus sylvestris L 



3. Sphagnum 1-3 ft. 



4. Pinus sylvestris L 



5. Eriophorum 5 ft. Calluna (abundant in upper layers) 



6. Betida alba L 2-3 ft. Menyantlies trifoliata L. 



Eriophorum vaginatum L. 



7. Empetrum nigrum L iHit. Eriophorum, Polytrichum 



8. Salix arbuscula L Belula nana L. (abundant in upper 



layers). Dryas octopelala L. Po- 

 tentilla comarum, Nestl. (abundant 

 in the lower layers). 



Total peat 13-16 ft, 



9. Sand 



10. Closely packed stones 



While most Swedish and many German authors refer the strat- 

 ification of the peat to successive changes in the level of ground wa- 

 ter as outlined above, other authors follow James Geikie, who re- 

 fers this alternation of vegetation to changes in climatic conditions 



