The area of a fringing reef that is closet to land is called the reef flat. When viewed at low tide, this part of the fringing reef is quite disappointing because usually it is covered with mud and plants that thrive in this slush. Very little coral is found in a reef flat.
The fringing reef slope is the part that is nearest the ocean. This area is where the corals are found. The corals here form microatolls, so called because they resemble little islands. These colonies of coral are built up on top of each other, the dead coral being on the top and the living animals below. They grow mainly in an outward formation.
An immature fringe reef that is in the beginning stage of forming is known as an apron reef. Apron reefs cover a small area and may not be continuous in formation. They are common in Hawaii.
Barrier reefs, of which the most famous is the Great Barrier Reef in Australia, are mature fringe reefs that contain a large and diverse collection of coral. As the reef keeps growing, the shoreline on which it was initially attached eventually erodes away and it becomes a freestanding reef. The Great Barrier Reef in Australia is more than 1,400 miles long and ranges between 14 miles and 149 miles from the Australian shoreline.