AVA | REPORTS ON THE STATE OF SCIENCE. 
The salient features of all the peat lying in this district may be sum- 
marised as follows :— 
The upper forest consists of two layers—the upper of Pinus sylvestris 
and the lower of betula alba. They are separated by 1-4 feet of peat, 
which in some places is formed from Hriophorwm and other peat bog 
plants, and in others by peat formed from Betula nana, Salix reticulata, 
and S. arbuscula. This seems to be the usual character of the Upper 
Forest over large tracts of the Highlands. It has now been found on the 
Spey-Findhorn Watershed, Findhorn-Nairn Watershed, Coire Bog, Easter 
Ross, in Assynt, and also near Altnabreac, further east than the present 
area. So far arctic plants between the two layers of the upper forest 
have only been found in Assynt, on the Grampians, and in the present 
area, The absence of any plants in the upper forest indicating colder 
conditions than prevail over lowland areas at the present day is signifi- 
cant, and suggests that the two layers of forest indicate genial conditions, 
whilst the intervening peat was accumulated under sub-arctic or arctic 
conditions. Evidence bearing upon this point has been obtained from 
Cross Fell and will be described presently. It is evident that the area 
under consideration exhibits the same sequence as other Highland areas 
investigated during 1905 and 1906. 
Most of the peat began to form under arctic conditions, when a 
close growth of Salix reticulata, Arctostaphylos alpina, Empetrum nigrum, 
Dryas octopetala and mosses covered the ground. 
This vegetation was succeeded by birch forest with Calluna vulgaris 
and Lychnis diurna. In some places the birch attained a fair size, but in 
the Strathy Basin the ‘forest’ appears to have been formed of very small 
or shrubby trees. The trees were succeeded by peat bog plants such as 
Eriophorum, Scirpus ceespitosus, and Sphagnum in some places, and by 
Betula nana, Salia reticulata, S. arbuscula in others. This sequence is 
so widespread that it must indicate a general change in climatic conditions 
at this time. A second forest succeeded the peat bog and arctic vegeta- 
tion, and this is covered with Hriophorum, Scirpus, and Sphagnum peat 
persisting to the present day. 
The Cross Fell District. 
All the peat for several miles round Cross Fell lies at altitudes above 
2,000 feet, rising nearly to the summit at 2,930 feet. In depth it varies 
from 10-15 feet at lower levels to 3-4 feet near its upper boundary. 
The only area free from peat is an outcrop of limestone on Rake End, 
forming the northern boundary of the Tees basin near its head, and a 
small limestone outcrop forming Bulmans Hills in the basin of the river 
S. Tyne, to the N.E. of Cross Fell. These outcrops are covered with 
pasture ; elsewhere the peat forms a continuous sheet, covered with 
Eriophorum, Calluna, Vaccinium Myrtillus, Rubus Chamemorus, and 
Empetrum, or furrowed into deep peat hags quite bare of vegetation. 
The peat was examined by means of sections and borings at its upper 
boundary near the summit of Cross Fell, and in the basins of the Tees and 
Tyne. The deposits in the basin will be described first. 
At about 2,000 feet the general sequence is as follows :— 
1. Sphagnum peat with Calluna and Empetrum. 
2. Carex peat. 
3. Betula alba with Alnus glutinosa, Lychnis diurna, Ajuga reptans, Elatine 
hexandra, Ranunculus repens. 
