De Maillet was a French diplomat and traveller, whose posthumous work Telliamed (his name spelled backward) was published in 1748. A cosmogony, covering the creation and pre-history of the Earth, it argued that all rocks and all forms of life had their origin in a diminishing ocean. He considered the Earth to be more than 2 billion years old. De Maillet’s belief in mermaids and mermen made his book an object of easy ridicule by later naturalists.