ON PEAT MOSS DEPOSITS. 411 
Work was commenced at the beginning of January 1906 on the Cross 
Fell area, continued during part of March and April 1906, and finished 
in April 1907. ‘The time taken by the work in this area is accounted for 
by the complicated character of the beds and the frequent occurrence of 
snow and frost, rendering the work of section-cutting unusually tedious. 
Field work on the Caithness-Sutherland border was begun and com- 
pleted during July 1906. 
The succession in these two regions will be described first, and after- 
wards the correlation of the strata with those in other districts will be 
briefly discussed. 
The Caithness-Sutherland Border. (Ordnance Survey Sheets 109, 115.) 
One of the most extensive tracts of peat in Scotland is situated in this 
region. Northward of the Torridonian sandstone hills of Ben Griam 
Mor and Ben Griam Beg a platform of crystalline schists stretch up to 
the north coast for a distance of twenty miles, and nearly the whole of this 
platform is covered with peat over 10 feet in thickness. Sections were 
taken in the basins of the rivers Halladale, Strathy, and Armadale Burn 
over ground lying between 400 feet to 800 feet altitude. 
The present vegetation of the whole area is one very characteristic of 
the west and north-west Highlands. The most abundant plant on the 
moors is Scirpus cespitosus, mixed with much Rhacomitrium lanuginosum, 
Myrica Gale, and, in less abundance, Hrica Tetralix, Calluna vulgaris, 
Eriophorum vaginatum, Drosera longifolia. The peat is deeply chan- 
nelled in places, exposing to view one, or more, generally two, forest beds 
of pine. 
"The sections taken in the Halladale basin will be described first. 
Near the head of Dyke Burn (one of the larger tributaries of the 
Halladale) is a semicircle of well-preserved moraines. Although the 
slopes of these are almost free from peat, the hollows between them are 
covered with peat to the depth of more than 15 feet. 
_The moraines lie at an elevation of 700 feet and about three-quarters 
of a mile north of the summit of Ben Griam Beg. 
The succession of strata between the moraines and Ben Griam Beg is 
as follows :— 
Characteristic plants. Accompanying plants. 
. Scirpus cespitosus. . Sphagnum. 
. Pinus sylvestris. . Calluna vulgaris, Betula alba. 
. Betula nana. . Salix reticulata, Empetrum nigrum. 
. Betula alba. . Calluna vulgaris, Empetrum nigrum 
(scarce). 
. Hypnum sp. and lichens. 
. Salia reticulata. 
rei rm Cob ee 
Or PwnNe 
. Salia arbuscula, Dryas octopetala 
Hypnum sp. 
Sand and gravel. 
Total depth 17 feet. 
Considerable difficulty was experienced in cutting many of the sections 
owing to the numerous large trunks of pine in zone 2. These had to 
be cut through with axe and saw before the underlying peat could be 
excavated. 
The most noticeable features here are the two beds of forest separated 
by arctic plants and the arctic plant bed occurring at the base of the 
whole series, 
