Aquarium Sand vs Gravel: the Pros and Cons
Beaches and Dunes. Beaches and dunes occur in a variety of shapes, sizes, compositions, and coastal settings throughout the United States. Beaches are generally defined as stretches of sand or smaller loose particles (such as pebbles, shells, or gravel) that exist between the water and the land. Dunes are landforms that occur when there is a sufficient supply of sand or sediment and strong ...