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ON THE PLANT REMAINS IN THE SCOTTISH PEAT MOSSES. 709 
is very sharply marked ; there is no gradual transition from Eriophorum conditions to 
Hmpetrum and Arctic willow conditions, and this may indicate that some time elapsed 
between the close of the Eriophorum formation and the beginning of the Empetrum, 
Salix, and Loiseleuria formation, during which time no peat was formed. The Arctic 
beds, although only 4-6 inches thick, may have required a length of time for their 
formation altogether incommensurate with their thickness. Such plant associations 
having Empetrum as the dominant plant, with Arctic willows and trailing plants such 
as Loiseleuria, cover large areas in Central and Southern Greenland and have been 
described by Warmine (8), and this goes to show that the conditions then obtaining in 
the upland valleys of Galloway and Tweedsmuir were essentially similar to present- 
day shrub-tundra conditions in Greenland, and very similar to what might have been 
expected to prevail during the period of mountain valley glaciers when the snow-line 
lay at about 2500 feet, thus giving a permanent snow-cap to the highest hills of the 
Southern Uplands. The evidence thus collected from upland peat occupying the same 
position with regard to the valley moraines both in Galloway and Tweedsmu1, agrees 
in almost every detail. The woodland at the base of the Tweedsmuir peat throws 
some light upon the character of the structureless peat met with in some of the sections 
of the Merrick-Kells district. During the interglacial period following the district ice- 
sheets and valley glaciers, two types of woodland flourished in the Tweedsmuir district : 
the first consisted of such trees as Corylus, Alnus, and temperate willows ; the second 
of more northern types, such as birch. The sections near Yellow Tomach, in the 
Merrick-Kells district, also show the same feature—temperate willows at the base 
merging above into birch, and patches of Calluna. In other sections in the Merrick 
district the birch rested upon peat in which no plant remains could be recognised ; but 
the original vegetation here was probably of the same character as that found farther 
north in the same district, and also in Tweedsmuir. The latest forest in the Merrick- 
Kells mosses is pine, and in the Tweedsmuir district, birch; but this hardly prevents 
comparison between these beds, as it might be expected that diversity of tree vegeta- 
tion would occur in different parts of the country during a forest period—even as tree 
distribution ditfers at the present day. 
THE Hini-rop Peat oF THE MoorFoor HILLs. 
(One inch Ordnance Survey—-sheet 24.)—The lower boundary of the peat in the 
Moorfoot Hills closely follows the 1750-feet contour line, seldom occurring below, and 
generally running somewhat above. From here the peat stretches upwards, and covers 
the summits of the highest hills up to 2136 feet. The peat-covered ground is tenanted 
by an association dominated by Ericphorum vaginatum, L.; Calluna vulgaris, L.; and 
Vacceinvum Myrtillus, L., with Rubus Chamaemorus, L., on the higher ground ; whilst 
the lower slopes below the peat covering are dominated by Nardus stricta, L. The dis- 
tribution of the different plant associations covering this ground has been described in 
detail by Rozerr SmirxH (9). Nowhere in the districts investigated can the present 
