These barriers protectors are located between Barlovento of the winds and the oceanic currents, that are separated from the keys located to the north of the archipelago by a great central lagoon of still waters with a greenish bottom that is sometimes interrupted by smudgy coral riefs or prairies of marine grasses. This great central lagoon of the archipelago has been denominated bay or under of "The Corrals". Its approximate surface is of 400 square kilometers.To the south of the archipelago a narrow and abrupt submarine platform appears where the depths of the sea oscillate between the 500 and the 1.000 meters. To the north, the platform is but wide and the depths are inferior to the 10 meters.
The keys that compose the archipelago have been classified and they were surrounded with the system used in Australia that is divided in six categories assisting to the size, the vegetable covering and the sedimentary atmosphere in that it have been developed.

1. - Sandy keys without vegetable covering and with little stability known as "Pelones", are the most numerous in the archipelago.

2. - Sandy keys covered with low vegetation, bushes and gramineous that are more stable than the previous class due to the presence of the vegetable covering that fixes the sand and it avoids the erosion.

3. - Sandy keys where there is vegetation of gramineous, bushes and cringing plants; with these it can have beach rocks originated by the segmentation of the sand or of the coral gravel, which forms "Storm Terraces."

4. - Sandy keys of a lot of extension covered with gramineous and that in certain places form a surrounded bay of mangrove; there are big accumulations of coral gravel and fragments of mollusks, result of the erosion caused by the sea.

5. - Keys of great size that have a lagoon open of flat waters, where the depth is smaller than 3 meters; the vegetation is of gramineous and swamp formations that skirt the lagoon; there are also storm terraces and beach rock