X.
level of high tides (owing partly to the retention by
the vegetation of drifted organic and inorganic sub-
stances, and of silt suspended in the tidal waters), it
it is found on inclosure and drainage to sink about
six or seven feet below the high-water level, the
difference being due to the previous constant satura-
tion.
These facts, coupled with the difficulty of ascertain-
ing without elaborate observation the mean level of a
sea so subject as the North Sea to be influenced by the
set of the winds and the outline of the coast, render
it necessary to observe very great caution in collecting
evidence as to either elevation or subsidence within
this area.
Without committing myself to the expression of a
positive opinion, I wish to place on record certain
facts and reports bearing on the subject which may be
of use to future observers.
A bed of peat, resting on freshwater shell-marl,
occurs in the bed of the Orwell, below Ipswich, 14
feet below low-water mark. (J. E. Taylor, British
Assoc. 1875.) A submerged forest, with stools of
trees in position of growth, is said to occur in the
Stour at Dovercourt.
In the alluvium of the foreshore in front of the town
of Walton-on-the-Naze have been found fine specimens
of Cervus megaceros and other extinct mammalia. The
old Bath House Hotel was originally erected about 30
yards nearer to the sea; its modern substitute is now
beaten by the spray at spring-tides, and the road in
front of it is occasionally flooded. This may be due
(1) to a slipping seaward of the alluvium down an in-
clined plane of London Clay, (2) to such alteration of
the slope as enables the water to run further up, or
(3) to real subsidence.
Between Clacton and St. Osyth, a submerged
forest occurs on the foreshore. A legend, current in
the neighbourhood, attests the former existence of a
parish named Alton somewhere off the present coast-
line thereabouts. A farm there is called Alton Park,
but no mention is made of Alton by Morant or other
historians. It may have been on a London Clay
island or peninsula now destroyed. The forest with
the elm stools still in place, forms the foreshore from
below the lowest ebb-tide level up to a line of dunes
which protect a low cliff of London Clay. The sea is
attacking and removing the ancient soil, although de-
position is going on a few miles further West. This
forest is probably of about the same age as the Wal-
ton alluvium, but on this point there is no positive
evidence from either physical or paleontological
sources. The space covered by it, and the nature of
the material (unctuous blue clay, full of twigs and
pieces of wood) forbid the supposition that the tree-