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White cliffs of Dover

2007 Schools Wikipedia Selection. Related subjects: Geography of Great
Britain; Geology and geophysics

   The location and extent of the white cliffs of Dover.
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   The location and extent of the white cliffs of Dover.
   The white cliffs of Dover
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   The white cliffs of Dover
   The cliffs seen across the channel from Cap Gris Nez, France
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   The cliffs seen across the channel from Cap Gris Nez, France

   The white cliffs of Dover, immortalized in popular song and verse, are
   cliffs which form part of the British coastline facing the Strait of
   Dover and France. The cliffs are part of the North Downs formation. The
   cliff face, which reaches up to 350 feet high, owes its striking façade
   to its composition of chalk (pure white lime) accentuated by streaks of
   black flint. The cliffs spread east and west from the town of Dover in
   the county of Kent, an ancient and still important English port.

   The cliffs have great symbolic value for Britain because they face
   towards Continental Europe across the narrowest part of the English
   Channel, where invasions have historically threatened and against which
   the cliffs form a symbolic guard. Because crossing at Dover was the
   primary route to the continent before air travel, the white line of
   cliffs also formed the first (or last) sight of the UK for travellers.

Location

   The cliffs are located along the coastline between approximately:
   Latitude 51°06'N, Longitude 1°14'E and Latitude 51°12'N, Longitude
   1°24'E. Shakespeare Cliff marks the point where England most closely
   approaches continental Europe. On a clear day, the cliffs are easily
   visible from the French coast.

Geology

   Evidence of erosion along the cliff top
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   Evidence of erosion along the cliff top

   The cliffs are composed mainly of coccoliths and trace their origins to
   the Cretaceous Period, approximately 136 million years ago, when the
   area between Britain in the west and Sweden/Poland in the east was
   submerged under deep tropical waters. Subjected to the great pressures
   of the sea, the emptied skeletons of coral, sponges and other small sea
   creatures turned to sediment and began to accumulate on the ocean
   floor. By approximately 70 million years ago, this process had formed a
   mass of silica-specked chalk covering huge areas between Britain and
   the Baltic Sea — white cliffs like those of Dover (but smaller) are
   also found on the Danish islands of Mon and Langeland or the coasts of
   the island of Rügen in Germany. The chalk layer used to lay high above
   sea level during the ice ages and in many places additionally was
   covered with glaciers. After the ice ages, they were exposed to the
   rising sea. Owing to the exceptional softness of chalk, tidal forces
   have since then significantly eroded this land mass away, in Dover to
   form the English Channel.

   The cliff face continues to erode at an average rate of one centimetre
   per year, although occasionally—most recently in 2001—large chunks of
   the edge, up to several metres at once, will fall into the channel with
   little warning. Visitors are therefore urged to remain at least five
   metres back from the edge.

Ecology

   Close up of the cliffs from the walk along the ridge
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   Close up of the cliffs from the walk along the ridge

   Several species of cliff nesting birds nest on the cliff face,
   including, fulmar and colonies of Kittiwake. However, contrary to the
   words of the famous song ("There'll be bluebirds over the white cliffs
   of Dover"), bluebirds are an American species not found in the UK.

Defence

   Behind the cliff face are miles of hidden tunnels that were created
   during the Middle Ages and later played a role in the defence of
   Britain during the Napoleonic Wars. The tunnels were later enlarged to
   become the Secret Wartime Tunnels beneath Dover castle.
   Retrieved from " http://en.wikipedia.org/wiki/White_cliffs_of_Dover"
   This reference article is mainly selected from the English Wikipedia
   with only minor checks and changes (see www.wikipedia.org for details
   of authors and sources) and is available under the GNU Free
   Documentation License. See also our Disclaimer.
