Coral reefs of the Virgin Islands other coral larvae to attach to and grow on. These corals can form into three different structures; fringing reefs, which are reefs that are close to the shore, barrier reefs, which are reefs that are alongside the shore and is separated by deep water, and an atoll reef which is a coral reef that circles a lagoon or body of water. As stated, the coral reefs such as fringing reefs, deep reefs, patch reefs and spur and groove formation are distributed over three islands in the Virgin Islands which are St. Croix (Salt River Bay National Historical Park and Ecological
Coral reef cannot grow above sea level. As the name implies, coral reefs are made up of coral skeletons from mostly intact coral colonies. As other chemical elements present in corals become incorporated into the calcium carbonate deposits, aragonite is formed. However, shell fragments and the remains of coralline algae such as the green-segmented genus "Halimeda" can add to the reef's ability to withstand damage from storms and other threats. Such mixtures are visible in structures such as Eniwetok Atoll. Since Darwin's identification of the three classical reef formations – the fringing reef around a volcanic island becoming a barrier reef and