MICROPALÆONTOLOGY OF POSTGLACIAL DEPOSITS. 471 
mentions the presence of submerged peat, and Mr. D. Mackenzie, of 
Stornoway, has kindly told me that such peat also occurs at the new quay 
of Stornoway Harbour and in the wick S.W. of Arnish Point (N. of Tob 
Leirabhaidh). 
Unfortunately, whilst I was in Lewis, the tides were not low enough to 
permit of sections being cut. By analysing samples of submerged peat we 
should get a number of fixed points much more useful for purposes of 
correlation than many forest-beds. 
Peat Moss No. 11. (Text-fig. 11.) 
Situated S.W. of Steinish, between the Steinish road and the little stream 
west of it. A shallow deposit (108 cm.) resting on sand; the surface 
covered with a firm grass meadow with Anthoxanthum, Juncus effusus, 
Nardus, Trifolium repens, Viola palustris, ete. 
The lowest sample, which showed fragments of Spongze needles, spores of 
Polypodium vulgare, and pollen of #pilobium, has a high frequency of pine- 
and hazel-pollen and a low one of alder; it thus exhibits the main features 
TEXT-FIG. 11. 
0 10° 20 30 40 50 60 70 80°) 
sO 
| 
14 
[ m - J——dq-— ——— 3 
—o— Alnus. —O— Betula. —e— Pinus, vee Ulmus. 
Quercus. -------- Tilia. --m-- Corylus. 
of the A-zone. The 3 samples analysed showed a high frequency of Salix 
pollen (in sample 1, 50 per cent.; 2, 150 per cent. ; 3, 75 per cent.), which, 
however, must not be regarded as a proof of a colder climate, because local 
willow-clumps along the stream or the sea-shore could well have caused this 
high pollen-frequeney. In Lewis it is to be remarked there is a considerable 
difference between the PF of the younger layers and that of the older. 
This fact and its great theoretical importance with regard to the statistical 
method of pollen research is dealt with in another paper (Erdtman, 1924), 
to which I beg to refer. 
Peat Mosses Nos. 12 a and b. 
The former is situated on the sea-shore between Stcinish and the mouth of 
the stream west of it. The deposit is certainly decapitated, the surface 
being clothed with Ulex europwus, Pedicularis silvatica, Eriophorum poly- 
stachion, Potentilla Tormentilla, ete. 
