Stromatolites are rare in today's ocean but living stromatolites have been found along the margins of the Exuma Sound, including Lee Stocking Island, Stocking Island, Highbourne Cay, Little Darby Island, and in the Exuma Cays Land and Sea Park.
Stromatolites are the oldest known macro-fossils, dating back over three billion years. They form an unusual and special type of reef structure in shallow water. Unlike most present-day reefs, which are composed of coral, stromatolites are formed by microorganisms. Scientists believe that the photosynthetic activity of cyanobacteria are the most important group of stromatolite-forming micro-organisms generating oxygen in our atmosphere.