The island of Bermuda has been formed by millions of years of sea level changes and especially wave activity.  Changing sea levels have allowed waves to forcefully pound and scour the volcanic base of Bermuda into the desirable location that it is today.  Waves transform coastlines in two ways: by erosion and deposition.

Erosion is "the process by which the surface of the earth is worn away by the action of water, wind, waves, etc." (Dictionary.com, 1997)  Waves erode coastlines in several ways.  The force of waves loosens and eventually detaches rock from coastal landforms.  When waves break on the shoreline the sediment that they are carrying acts as sand paper, scouring the rock on the landforms.  "In limestone areas like Bermuda waves assist in dissolving away the soluble limy matter, until rocks begin to crumble and fall." (Watson, et al., 1965)  All of these processes occur on the coasts of Bermuda.

Bermuda's coasts feature marine cut cliffs, sea worn caverns or caves, natural arches, stacks, and pot holes.  All of these coastal landforms occur due to wave activity over time.  Marine cut cliffs are formed when waves crash into the base of a hill, carving out the rock.  Sea caves occur when waves carve out weak rock from a cliff face.  Over time, sea arches are formed when waves carve straight through rock formations which jut out into the sea.  When the sea arch collapses, free-standing rock formations, called stacks, remain, "relics of collapsed caves." (Watson, et al., 1965)  Holes, called pot holes, are formed when trees growing on the shore are uprooted during storms.  Waves come in and swirl around the pot holes and the sediment cuts into the rock, digging the holes deeper.

A second way that waves shape coastlines is by deposition.  Deposition is "the laying down of matter by a natural process." (Dictionary.com, 2007)  Waves deposit sediment in several different ways.  When waves crash against hills or cliffs, erosion occurs.  As a result of erosion, pieces of fallen rock and rock broken off by the force of the waves are pulled out when the waves roll back into the sea.  The force of the water pulls the rocks away from the base of the cliffs.  Larger rocks are deposited in shallow water and smaller rocks and sediment are carried deeper.  The deposited rocks and sediment breaks the force of the waves and cause the waves to break further and further out.  Waves rarely hit the shoreline head-on and almost always come in at an angle.  This process, called littoral drift, causes the sediment to be carried as far as the wave can carry it at an angle and then roll back down the slope of the shore.  This process is repeated millions of times and eventually the sand particles are deposited in the bays where most beaches are found on Bermuda. 

Bermuda has several depositional features including beautiful beaches, sand spits or spits, bars, tombolos and sand dunes. The marine cliffs found on Bermuda's shore are made up mostly of limy sandstone, which is broken up into sand particles and transported to the bays by wave activity.  This is the reason that Bermuda's beaches are filled with clean, fine sand.  "Where a bay exists, the sand is carried out into open water as a long finger or sand spit." (Strahler and Strahler, 2006)  Spits usually occur in the mouth of a bay.  As sand spits grow and reach across the entire bay, a bar is formed.  Tombolos are formed when sediment deposits connect a small island to the mainland.  Sand dunes are formed when there is an accumulation of loose sand which is blown by the wind to form large or small piles of sand.

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