There is no distinct line between a beach and dune because sand is always being exchanged between the two features. At a point higher on the beach where water cannot reach under normal weather circumstances, the wind begins to shape the sand into dunes and other sand formations. Sand deposits from the berm crest often extend far inland, the result of large storm waves. Further out to sea at one of the longshore bars, there are underwater embankments where waves break. At the bottom portion of the face there is usually a trough. A beach berm is also considered a deposit of material (loose rock, sand, shingle or cobble) formed by the forces of the ocean water. The berm has a crest at the top and a face, which is the slope leading down to the water. The beach berm is the part of a beach above water (depending on the tide) that is actively influenced by the waves at some point in the tide. In Bascom’s description, a beach can either be a small system where rock material moves off and onshore by the force of waves and currents or a geological unit of considerable size. Based on his revised description, beaches also include the submerged longshore bars. In 1980, William Bascom challenged the idea that a beach is simply a set of sand put in motion by waves to a depth of 10 m or more along coasts.
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