The enclosed and almost tideless Baltic apparently tells the same
story, for at Rostock at its southern end, a submerged peat-bed has
been met with at a depth of 46 feet.
On passing northward into Scandinavia we enter an area in which,
as in Scotland, recent changes in sea-level have been complicated
by tilting, so that ancient beach-lines no longer correspond in
elevation at different places. The deformation has been so great
that it is impossible to trace the submerged forests; they may be
represented in the north by the raised beaches, which in Norway and
Sweden, as in Scotland and the north of Ireland, seem to belong to
a far more recent period than the raised beaches of the south of
England. It seems useless to attempt to continue our researches on
submerged forests further in this direction, especially as during the
latest stages, when we know England was sinking, Gothland appears to
have been slowly rising. Those who wish to learn about the changes
that took place in the south of Sweden should refer to the recent
monograph by Dr Munthe.
CHAPTER V
THE IRISH SEA AND THE BRISTOL CHANNEL
On the west coast of Scotland, as on the east, the succession of
events seems to have been quite different from that which can be
proved further south. It looks as though we must seek for equivalents
of our submerged forests in certain very modern looking raised
beaches and estuarine deposits, such as those of the Clyde. Even when
we move southward to the Isle of Man deeply submerged post-glacial
land-surfaces appear to be unknown, though there is evidence of a
slight sinking, and roots of trees are found a few feet below the
sea-level. In the Isle of Man we still come across the modern-looking
raised beaches so prevalent in Scotland though unknown in England.
The Lancashire and Cheshire coasts, with their numerous deep
estuaries and extensive flats, are noted, however, for their
submerged forests, sometimes seen on the foreshore between
tide-marks, sometimes laid open in the extensive dock or harbour
works. The Heysham Harbour excavations, for instance, were carried
far below sea-level and a thin peat-bed was met with in a boring at
52 feet below Ordnance datum. Mellard Reade considered this peat
once to have been continuous with an ancient land-surface seen
between tide-marks. A boring is not altogether satisfactory evidence
for the occurrence of a land-surface at such a depth; but if it is
trustworthy it points to a subsidence of about 60 feet, an amount
identical with that observed in the Thames Valley.
The estuaries of the Ribble, Mersey, and Dee tell a similar story,
for on their shores and under their marshes are found some of the
most extensive submerged land-surfaces now traceable in Britain. Many
accounts of these have been published; but the alternations of marine
with freshwater strata and with land-surfaces are so like those
already described that a short account will suffice.
Public-domain text, read in full here on John Shaqi.
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