Complex sentence: Near the centre of the lagoon is the only permanent land of the reef, Heralds-Beacon Islet, a small cay measuring 600 m by 120 m, with an area 57,000 m 2, rising only a few metres above the high-water mark.
Split into simpler sentences: Near the centre of the lagoon is the only permanent land of the reef-Heralds-Beacon Islet. The island is a small cay measuring 600 m by 120 m, area 57,000 m 2, only rising a few metres above the high-water mark.