retees

Example:Many islands in the Caribbean are actually 'cays', which are formed by the growth of coral on the edges of reefs.

Definition:Small, low, sandy islands off the coast of tropical regions that lie near coral reefs.

Example:The Maldives consists of 26 atolls, each of which is a ring of coral islands surrounding a central lagoon.

Definition:Circular or annular coral formations composed of a coral reef surrounding a lagoon.

Example:Shoals can create hazardous navigation for ships if they are not mapped and marked.

Definition:A sandy or gravelly area of seabed that is only shallowly submerged at high tide.