MICROPALÆONTOLOGY OF POSTGLACIAL DEPOSITS. 475 
A boring was made east of moss No. 15 at the western point of the little 
loch to which the water from Loch Mor a? Ghrianain and L. Mor a Chrolaich 
drains before it flows to Allt na Craoibhe. In the loch was a very sparse 
flora (Carex rostrata, Menyanthes, Potamogeton, ete.). 
Sequence :— 
A. 175 cm. Sphagnum peat; not at all a typical one ; fairly rich in 
Ericaceæ remains. 
B. 50 em. of a substance resembling a (Carex peat, forming a transition to 
O. 252 cm. gyttja, of which the colour ranges from dark brown to yellow- 
green. 
D. 3 em. 4- clay, sandy. 
The laver A has a low PF: Ericaceæ tetrads, however, are common; for 
instance, in sample 3, where they form 300 per cent. of the total pollen. 
Layer B and, in a higher degree, layer € are rich in pollen, except the 
lowest samples from C. | In sample 13 only 18 pollen-grains were counted : 
9 Betula, 9 Pinus. Myriophyllum alterniflorum pollen occurred here with a 
frequency of 112 per cent. It is curious that this pollen was found also in 
sample 5 (sporadic) and 6 (16 per cent.).] 
The diagram differs considerably from the diagrams already mentioned ; 
it is noteworthy that Corylus pollen is almost absent. Undoubtedly pollen 
masses from local birch forests have considerably influenced the pollen-flora 
(ef. samples 9-12), and it therefore seems difficult to localize the A-zone. 
Sample 5 shows a great pine-pollen percentage, but it is more probable that 
the layer from which sample 8 was obtained originated at the time of the 
A-zone. The presence of pine-pollen in all samples from this deep deposit 
does not favour the view that pine did not grow in Scotland before the 
Upper Forest time, 
Peat Moss No. 17. 
Situated W. of Stornoway and X. of Loch Garbhaig, N. of the old road 
to the north of Amhuinn a Ghlinne Mhoir, a little N.W. of point 250. 
Beneath 263 em. of peat with Sphagnum, Carew, and Scirpus cespitosus 
remains, there follows a gyttja bed, 32 cm. thick, resting on sand. From 
the gyttja layer pollen-grains are practically absent, the analysis of a sample 
taken 15 em. above the sand showing only a single pollen-grain (bireh). A 
sample from the peat 255 cm beneath the surface gave the following results: 
Betula 92 per cent., Pinus 6 per cent., Quercus 1 per cent., Ulmus 1 per 
cent.; Corylus 3°5 per cent. 
Prat Moss No. 18. 
Situated on the W. coast of Lewis, near East Loch Roag, beside the road 
a little N. of Breascleif. The sequence is 170 em. thick. In the oldest 
layers, which rest on rock, only 1 Acer, 12 Betula, 1 Pinus (1 Quercus ?), 
and 2 Myriophyllum alterniflorum pollen were met with. Also 2 spores of 
Polypodium vulgare, pollen of Cyperaceæ and Gramineæ, Pediastrum sp., 
and Ostracod remains were recorded, 
