The Atlantic is a trailing-edge coast, meaning that it is the side of the continent moving away from the mid-ocean spreading center. The Atlantic coast contains numerous variations due to the geology, sediment supply and climatic differences along the shoreline.
The glaciated coast of northern New England contains rocky islands and pocket beaches between bedrock bluffs, while the mid-Atlantic region features sandy barrier islands and spits that border the mainland. Drowned river valleys on the southern Atlantic coast also contain barriers that formed differently than those to the north. At the southeastern edge of the coast, coral reefs are the predominant coastal landscape.
From Maine to Florida the coasts change drastically, but the entire Atlantic coast has a wide continental shelf and gradually sloping coastal plain. As a result, most sediment is derived from relict beaches and offshore sources. Furthermore, even a slight rise in water level can flood low-lying areas, making these coasts vulnerable to storm damage.