Pseudo-atoll Pseudo-atoll A pseudo-atoll, like an atoll, is an island that encircles a lagoon, either partially or completely. A pseudo-atoll differs from an atoll as established by several authorities, such as how it is formed (not by subsidence, nor by coral). It is considered a preferable term to "near-atoll". There is a need for rigorous definition of "pseudo-atoll" before it can be accepted as a general term. Alexander Agassiz gave the term pseudo-atoll to "any ring-shaped reefs not formed as a result of subsidence". while Norman D. Newell and J. Keith Rigby called such reefs non-coral. and "We conclude that almost-atoll
Gnaviyani Atoll a whole. NOTE: "Haa Alifu, Haa Dhaalu, Shaviyani, Noonu, Raa, Baa, Kaafu, etc.. (including Gnaviyani) are code letters assigned to the present administrative divisions of the Maldives. They are not the proper names of the natural atolls that make up these divisions. Some atolls are divided into two administrative divisions or contain half of an atoll (In case of Thiladhunmathi to Haa Alif, Haa Dhaal, Shaviyani and Noonu Atolls, Huvadhu Atoll to Gaafu Alifu and Gaafu Dhaalu Atolls and In case of half of Ari Atoll to Alifu Dhaalu Atoll), while other divisions are made up of two or more