Description

I wanted to include a definition of "dunes" so I found one at this site: 

 

http://geomaps.wr.usgs.gov/parks/coast/dunes/index.html

 

Sand Dunes - Coastal

Sand dunes form wherever environmental conditions provide sand, steady wind and a location for the sand to collect. This may occur in both coastal and terrestrial settings.

Coastal Dunes

Sand starts as bedrock, which is broken down into blocks, a size at which water is able to transport them downstream. Eventually these large blocks may be jostled around enough to be broken into sand-sized grains. Sand and other sediment usually ends up deposited along the sides of streams, in lakes, or in the ocean.