THE FAUNA AND FLORA FROM THE BRICK PIT AT LEXDEN 17
frequencies may be found in areas distant from vegetation with
Pinus as a result of long-distance transport into tree-less areas. A
similar explanation may apply to the frequencies of Pinus
observed in the Lexden samples. If the tree was represented in
the region it must have been rather sparsely distributed, as Pinus
is a high pollen producer.
The NAP includes high frequencies of grass, sedge and
Plantago pollen. In view of the large number of Carex nutlets
found in a small volume of peat, it is probable that much of the
sedge pollen is locally derived from the swamp vegetation sur-
rounding or in the pool where the mud was formed. The high
NAP indicates a regional open type of vegetation. Particularly
significant are the unusually high frequencies of Plantago pollen,
especially of P. media/major type. These are light-demanding
species and their high frequency may be associated with trampling
of the local vegetation by the large mammals whose remains are
found at the site. The pollen of Armeria, Artemisia, Plantago
maritima, the seed of Stellaria graminea and the spore of
Botrychium also indicate open vegetational conditions.
The pollen of Caltha and the fruits of Carex rostrata represent
two of the swamp plants of the local vegetation.
Mr. J. H. Dickson of the Botany School, Cambridge, has kindly
reported as follows on moss remains found in extracting beetles
from the peat. "The following mosses were found : —
Acrocladium giganteum (Schp.) Richards & Wallace, 9 fragments
Cratoneuron filicinum (Hedw.) Roth................... 3 fragments
These species have often been recorded from Quaternary de-
posits and, widespread in the northern hemisphere, extend beyond
the Arctic Circle. Both are calcieoles, Acrocladium giganteum
being found in rich fens, while Gratoneuron filicinum, although
sometimes found in such a habitat, is perhaps more characteristic
of flushes and streamsides with calcareous water".
Indications of climate. The prevalence of NAP and the almost
complete absence of pollen of thermophilous trees suggest a severe
climate. All the species represented have a wide distribution into
the north above the Arctic Circle in north-west Europe, but there
is no positive evidence of cold conditions in the plant remains.
Plantago maritima is found inland in northern areas, but its pre-
sence here may also be related to proximity of the sea at the time.
Indications of age. It is impossible to make any satisfactory
correlation with the Quaternary succession of East Anglia on the
basis of the two pollen samples analysed. There is no evidence
of the vegetational changes which usually permit such correlations.
Similar pollen spectra have been found in deposits from the
more severe parts of the Weichselian (Last) Glaciation, the end
of the Ipswichian (Last) Interglacial (Sparks and West, 1959), and
just before the Gipping Glaciation. It is therefore not possible to
put forward a correlation on the basis of the pollen analyses.