712 MR FRANCOIS J. LEWIS 
mixed with much Calluna. The zone of Empetrum running through the peat of the 
whole district suggests that, at some period, colder conditions prevailed; but the 
evidence afforded by Empetrum alone is scarcely conclusive, for, although covering large 
areas within the Arctic Circle, it also occurs fairly abundantly at the present day on 
many hills of about the same altitude as the Moorfoots, although never forming a pure 
association on the North of England or Southern Upland Hills. The presence of 
Arctostaphylos Uva-ursi also suggests more northern conditions, as it is not at present 
found on the Southern Upland Hills. 
If the Empetrum zone represents cold conditions during the formation of these 
mosses, it must either be contemporaneous with the same period which produced the 
Salix reticulata in the Merrick-Kells peat and the Loiseleuria in Tweedsmuir, or it 
must represent the later return to glacial conditions, when the Highland corries were 
tenanted by small glaciers whose trace can still be seen in the high level corrie moraines 
of the present day. The sequence of the beds above and below the Empetrum agrees 
so closely with that in the Merrick-Kells area and in Tweedsmuir, that I think the 
evidence is in favour of much the same—or, possibly, somewhat milder—conditions having 
caused its growth. If the Empetrum zone here is contemporaneous with the Arctic 
zone in the other districts, it might have been expected to contain plants still more 
Arctic in character, as the ground lies about 2000 feet instead of 800-1200 feet, and is 
not sheltered like the Tweedsmuir and Galloway valleys; and for this reason I suggest 
that the Empetrum zone in the Moorfoot peat is contemporaneous with the period of 
Highland corrie glaciers. ‘ 
THe Lowtanp Mossgs oF WIGTONSHIRE. 
(One inch Ordnance Survey—sheet 4.)—Between the towns of Glenluce and Newton 
Stewart, in Wigtonshire, hes an extensive tract of peat mosses which northward stretch 
as far as the Merrick district. The general level of the peat-covered ground lies at about 
200-800 feet above Ordnance datum. The whole of the district is flat in character, 
broken by a few ridges of Silurian rocks with their longer axes pointing N.N.H. and 
S.S.W. in the direction of the great centre of ice dispersal of the glacial period in the 
Merrick and Kells range. (Fig. 12.) The mosses here occupy great hollows in the till 
between the outcrops of rock. The present vegetation covering the wetter mosses con- 
sists of Sphagnum; Hrica Tetralix, L.; Myrica Gale, L.; Eriophorum vaginatum, I,. 
—with a little Calluna vulgaris with tufts of Cladonia rangiferina amongst the 
scattered Calluna patches. On the drier mosses Calluna is better represented, with 
Scirpus sp. and Kriophorum vagimatum as subdominant plants. 
The peat covering the district shows no sign of denudation ; the surface is even, and 
closely covered with vegetation. Drainage channels have been cut in many places, but 
owing to the low-lying level character of the ground they are not very effective. Peat 
is chiefly used as a fuel in the district, but owing to the sparsely inhabited nature of 
the country the mosses have not been trenched upon by turbaries to any great extent, 
