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View west from
Kimmeridge in Dorset towards
the dramatic coastline at Tyneham.
Coastlines are a complex, ever
changing environment, controlled by constructive and destructive forces that
shape and alter the characteristics of the landscape. An understanding of
the present day features and processes provides a valuable insight into the
comparable forces that have occurred for millions of years. Those studying
palaeontology will also find a knowledge of coastal features greatly assists
their interpretation of scientific literature and enables them to locate
productive fossil collecting grounds.
Figure 1: Diagram
showing the basic features of the coast.
Figure 1 above illustrates some of the common features present on
a rocky/cliff section of coast, in particular the backshore and
foreshore where fossils are more easily collected. Accessibility is
often dependent on a low-tide, which occurs every 12 hours
approximately. An example of a typical tidal cycle throughout a day
would be: Low (6:30am), High (12:45pm), Low (7:00pm), High
(1:15am). Tidal cycles are driven by the gravitational pull of the
sun and moon on the earth's oceans/seas, and amplified on a local
basis by the prevailing weather conditions.
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exposed at Peacehaven in East Sussex. Right:
Foreshore exposed at
Warden's Point on the Isle of Sheppey.
The distance between high and low-tide exposes an area of the
beach known as the foreshore (figure 1); provided neither seaweed
nor shingle accumulations are present, these wave swept expanses can
expose fossils in situ. As the waves and shingle scour the
foreshore, the situ rock is weathered away, leaving the harder
fossil remains protruding from the surface.
Left: A small
pyritised ammonite within the foreshore at
Right: A flint echinoid within the foreshore at
The photos above show a small pyritised ammonite (left) exposed
on the foreshore at
Charmouth and an
echinoid (right) preserved as
Peacehaven. Over the years some spectacular discoveries
have been made along the foreshores of the British Isles, including
complete marine reptile skeletons and giant ammonites measuring 6
Left: Two limpets
awaiting the incoming tide. Right: Four winkles
neighbouring a sea anemone.
The foreshore also accommodates rock pools, which are home to a
wealth of marine life; the photos above show two Limpets clinging to
an exposed boulder (left) and a collection of winkles neighbouring a
sea anemone (right). In many areas along the British coast the
foreshore is considered a zone of geological and/or biological
importance, and assigned a Site of Special Scientific Interest
(SSSI). Where a
SSSI exists, visitors are expected to show
additional respect for the area, it's usually illegal to remove
fossils from the foreshore (and cliffs) in these areas. Discovering
Fossils includes a notice within the location summary on
each of the relevant fossil locations, alerting readers to
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Left: Boulders on
the backshore at
Kimmeridge in Dorset. Right:
Fallen slabs and shingle accumulations on the backshore at
Seatown in Dorset.
Located between the high-water mark and the cliff or land is an area
known as the backshore (figure 1); this zone does not support
marine-life, as it spends the majority of its time above sea-level.
The backshore is an important fossil collecting ground, provided a
safe distance can be maintained from the cliff (if applicable - see
below). Large accumulations of fallen rocks and scree commonly form
at the base of tall cliffs, providing an opportunity to find freshly
exposed specimens. Please note, within cliff areas the backshore is
the most dangerous shore zone; large rocks (as pictured above) can
and do fall without warning. Further information about cliffs can be
Burton Bradstock tower
above the beach; collapses on to the backshore occur frequently
throughout the year, particularly during the winter months.
A cliff is a vertical or near-vertical rock face, typically
comprised of exposed situ rock and capped with present day/recent
soils. The majority of cliffs occur naturally where the land meets
the sea (figure 1), in particular when the coast is composed of
denser rock types that are less liable to slumping.
Cliffs are formed by a number of processes, in particular the
explosive energy released from waves (and stones carried within
them) crashing into their base, the result of which leads to
undercutting and eventual collapse of the overlying rock. Figure 2
below illustrates the process of undercutting; a large portion of
the cliff base has been eroded and the overlying rock sits
Figure 2: A diagram
illustrating the forces that lead to cliff formation.
Other factors contributing to cliff formation include precipitation
(rain/snow/hail), which penetrates the natural cracks and fissures
throughout the cliff, washing away and/or dissolving less resistant
rock and weakening the stability of the cliff. The rate of erosion
is accelerated by the freeze-and-thaw action during the winter
months, during which time the expanding ice cracks the rock further,
notably on the exposed outer surface. Erosion also occurs during
the summer months, at which time the cliff is warmed and the
evaporating water causes the sediment to contract and crack (porous
As a result of the forces outlined above, cliffs are
constantly changing and on the retreat; inevitably rock falls and
large scale collapses occur unpredictably throughout the year.
Left: A boulder
weighing in excess of a tonne lies imbedded in the shingle on the
backshore. Right: A cliff fall leaves many tonnes
of rock on the backshore.
Some of the most dangerous cliff localities in the UK include
Lyme Regis in Dorset and
in Yorkshire. We strongly recommend visitors keep a safe distance
from the cliff base, usually at least 8 meters; however if your
activities require that you pass close to the cliff, then a hard hat
Join us on a fossil hunt
Left: A birthday party with
a twist - fossil hunting at
Right: A family hold their prized ammonite fossil at Beachy Head.
Discovering Fossils guided fossil hunts reveal evidence of life that
existed millions of years ago. Whether it's your first time fossil
hunting or you're looking to expand your subject knowledge, our fossil
hunts provide an enjoyable and educational experience for all. To find