480 MR. G. ERDTMAN : STUDIES IN THE 
I. 4em. Sphagnum peat, bright, but little decayed ; fibres and rootlets 
of K. vaginatum. 
J. 6cm. Do., dark, greatly decayed. 
K. 2em. Do., bright, H<6. 
L. 10.cm. Do., brown; rootlets of Æ, vaginatum, scattered Calluna 
stems. 
M. 3em. Do., but brighter. 
N. 27 em. Do., dark, but H nevertheless <6; isolated small Calluna 
stems ; Eriophorum vaginatum roots abundant. 
0. 115 em. (107-222 em. beneath the present surface). Do., H 5-7(-8) ; 
at the top was a layer with small Calluna stems, not very clearly 
defined ; at 200 em. below the surface the bore was obstructed by 
solid wood ; lower down fossils occurred, which indicated somewhat 
1 
wetter conditions (e. g. Equisetum remains). 
T 
150 em. Dy, becoming greyish, gyttja-like or clayey lower down. 
40 cm. + tough, grey clay, in places mixed with coarse sand. 
e 
The section thus shows a great number of thin strata following one another 
irregularly, which indicates an evolution merely depending on local edaphic 
factors. 
From the layers A-O six samples have been analysed :— 
Sample 1 (10 em. below the surface) : 4 pine-pollen, attacked by Rhizo- 
=~ phidium ; then 1 Chenopodiaceæ pollen, 41  Ericacem- tetrads, 
1 Sphagnum spore, 
Sample 2 (50 em. below the surface): 1 Betula; 42 tetrads of Ericacem. 
Sample 3 (73 em. below the surface) : 1 Pinus; 31 tetrads of Ericacem. 
Sample 4 (112 em. below the surface): 2 Betula: 30 tetrads of Ericacem. 
Sample 5 (147 em. below the surface) : 1 Alnus, 5 Betula ; 250 tetrads of 
Ericaces. 
Sample 6 (197 cm. below the surface): 1 Acer, 5 Alnus, ll Betula, 
1 Carpinus, 1 Pinus ; 153 tetrads of Ericaceæ. 
Thus, summarized, we get a total of: 1 Acer, 6 Alnus, 19 Betula, 
1 Carpinus, 24 Pinus ; 547 tetrads of Ericacex, 
As there is nothing to indicate that there was ever a larger amount of 
pollen in these layers, which has since decayed, it is evident that the Orkneys, 
when these layers were formed, were practically without forests or large 
clumps of forest trees. Consequently they had the same character as they have 
at the present day. 
In the P layer no Ericace pollen is found, the six analyses made giving 
the following result :— 
Sample 7 (235 em. below the surface): 4 Alnus, 7 Betula, 2 Quercus : 
43 grass-pollen, 10 ef, Saliw. 
