Made from coral reefs and sand, Diego Garcia is one of these ring-shaped islands surrounding a lagoon
[DOC] [TLE] a treasure-trove of literature - Project Gutenberg Australia [PAR] The subject of corals and coral-reefs is one concerning which much popular ... of 
the then prevalent theory concerning the origin of the ring-shaped atolls--and the 
..... gives but a faint idea of the singular aspect of one of these lagoon-islands.