© Science Museum / Science & Society Picture Library
Colour engraving by Josiah Wood Whymper taken from 'Phenomena of Nature', published in London in 1849 for the Society for Promoting Christian Knowledge. 'Some parts of the ocean are studded with a peculiar kind of rock, very narrow, but stretched out to a considerable length. It is called a 'coral-reef' and is produced by innumerable small zoophytes, or 'coral-insects'. The burning sun helps transform this rocky base into solid stone, which gradually increases in thicknes until it becomes so high that it is only covered by the spring tides.'