40 



MR FRANCIS J. LEWIS 



In position the layer of Pinus (No. 2) and Betula alba (No. 5) agrees exactly with the 

 upper and the lower layer of pine separated by 18 inches of Sphagnum peat recorded 

 from the Spey-Findhorn watershed, Coire Bog, and the Findhorn- Nairn watershed (3). 

 Here, however, the lower layer of trees consists of Betula alba, and there are also traces 

 of this tree in the Pinus sylvestris zone. The occurrence of abundant Betula nana 

 between two such forest beds is of some interest, as similar plants in the same relative 

 positions have been observed in the mosses of the Grampian mountains and the 

 Caithness-Sutherland border. 



The third noteworthy feature is the fact that Betula alba tends to replace Pinus, 

 sylvestris. The same feature has been noted near the northern boundary of the upper 

 pine forest. 



The northern and lower-lying peat of the moss yielded much the same sequence, 

 although, as one would expect, some of the details differ, as the following section 

 shows : — 



Characteristic Plants. 



1. 



Scirpus peat. 





1. Sphagnum. 



2. 



Pinus sylvestris. 





2. Calluna vulgaris. 



3. 



Scirpus ceespitosus. 





3. 



\. 



Betula alba of large size. 





4. Corylus Avellana. 



5. 



Rliacomitrium lanuginosum. 





5. Stunted Calluna, Scirpus 



6. 



Sandy peat with much Equisetum sp. 





6. Hypnum sps. 







Sand ai 



id rock. 



Accompanying Plants. 



It will be noticed that here the whole of the peat between the two forest beds is 

 formed from Scirpus without any trace of Betula nana. 



2. Peat in the neighbourhood of Loch Urigill. — The peat occurs upon open undu- 

 lating moorland to the west of the Ben More Assynt, and Breabag ridges. The mosses 

 are generally level, and peat appears to be forming at the present time. Sections were 

 taken round Loch Urigill and Crom Allt — a stream draining into the southern end of 

 Loch Urigill. 



The upper forest zone is poorly represented, and pine is generally replaced by birch. 

 Moreover, none of the sections showed any trace of arctic plants at the base, thus 

 indicating that the earlier stages are missing. 



The general sequence is as follows : — 



Characteristic Plants. 



1. Scirpus ceespitosus. 



2. Pinus sylvestris. 



3. Scirpus rsesfritosus. 



4. Betula alba. 



Accompanying Plants. 



1. Calluna, Sphagnum. 



2. Calluna. 



3. Betula nana, Sphagnum. 

 Rhacomitrium lanuginosum. 



4. Corylus Avellana. 

 Sali.x purpurea. 



The Pinus sylvestris bed is absent in many of the sections, but the Betula, alba 

 zone (No. 4) is generally well marked. 



It should be pointed out that the peat is continuous for many miles to the south 



