The Structure and Distribution of Coral Reefs noted the location of the different types of coral around the reef and in the lagoon. In his diary, he described, "examining the very interesting yet simple structure & origin of these islands. The water being unusually smooth, I waded in as far as the living mounds of coral on which the swell of the open sea breaks. In some of the gullies & hollows, there were beautiful green & other colored fishes, & the forms & tints of many of the Zoophites were admirable. It is excusable to grow enthusiastic over the infinite numbers of organic beings with which
Coral Sea Islands and 1880s the islands were mined for guano but the absence of a reliable supply of fresh water prevented long-term habitation. The Coral Sea Islands became an Australian external territory in 1969 by the "Coral Sea Islands Act" (prior to that, the area was considered part of Queensland) and extended in 1997 to include Elizabeth Reef and Middleton Reef nearly 800 km further south, already in the Tasman Sea. The two latter reefs are much closer to Lord Howe Island, New South Wales, (about ) than to the southernmost island of the rest of the territory, Cato Island. The islands,