108 THE ESSEX NATURALIST.
as the Dogger Bank." It is also suggested that the deposit
exists in situ.
Later, in 1920, Mr. Whitehead published a further con-
tribution to our knowledge of moorlog ("More about 'Moorlog' :
a Peaty Deposit from the Dogger Bank in the North Sea."—
Essex Naturalist, vol. xix., pp. 242-250). Remains of
branches, roots and fruits in the deposit show the Birch to
have been widely distributed at the time of its formation ;
a few nuts prove the existence of Hazel, and leaf impressions
indicate the Willows, Salix aurita and S. repens. Numerous
pollen grains of a species of Pine—probably Pinus sylvestris—
form the only other evidence of trees (l.c, p. 243) in the moorlog.
As to the presence of other pollen grains in the submarine
ledges and cliffs of peat, Mr. Reid has found groups of stamens
of willow-herb (Epilobium) with well-preserved pollen grains,
though the whole of the rest of the plant to which they had
belonged had decayed (Submerged Forests ; Cambridge Univ.
Press, 1913, p. 45).
In November, 1924, with Mr. Whitehead's consent, the
bulk material of the moorlog was sent to me at Stockholm for
pollen-statistical investigation.
The results of my investigation are in full agreement with
those of Mr. and Mrs. Reid already quoted. Thirteen specimens
of moorlog were analysed for their pollen-contents. For the
method employed—that of Lagerheim and Von Post—see Journ.
of Linn. Soc. (Botany), xlvi., 1924. The average percentage
figures of the pollen recorded are as follow : Pine 72%, Birch
27.5%, Oak and Elm 0.5%, ; Hazel (calculated separately) 8%.
Figure 1 A. shows this pollen spectrum in a diagrammatic way.
For purposes of comparison, fig. 1 B. gives an idea of the
average spectrum of early "boreal" peats from S.W. Sweden
(Halland). The percentage figures (calculated from the spectra
of "niveau 80" of the peat-mosses, Nos. 4, 9, 21, 24, 35 and 36,
described in Arkiv for Botanik, Bd. 17, No. 10, 1921) are : Pine
62.5, Birch 37.1, "mixed oak forest" (elm) 0.3 ; Hazel 9.5.
These figures are in striking accordance with those on which
the moorlog spectrum, fig. 1 A., is founded.
The spectrum, fig. 1 C, must be regarded as being older than
spectra from the time during which most of the moorlog was
formed. It shows the percentage composition of the fossil