This is a real teaser. The obvious opener is: what on earth is it? A Stonehenge-type stone circle? Teeth? Sand castles? Or a glimpse into pre-history?

Darwin: Who was Charles Darwin (naturalist, 1809-1882), and what is Darwinism? (his 'On the Origin of Species by Means of Natural Selection' published in 1859). What does 'survival of the fittest' mean? ('natural selection' of those best adapted to survive; thus many species, like this plesiosaur, have died out). What do critics of Darwin say? (there are gaps in the fossil record, for instance, lack of intermediate types; however, there are often common ancestors) Prehistoric creatures: What do dinosaurs remind you of? Reptiles generally? Crocodiles? Lizards? Birds? What killed them off? Theories include an asteroid, X-rays, a supernova, extreme heat or cold, egg-eating mammals, sterility. Have they survived in any form? Birds? The Loch Ness monster? Why is 'The Flintstones' inaccurate? (dinosaurs extinct more than 60 million years ago; humanoids have existed less than a million years) Palaeontologist's report: Imagine you are the palaeontologist who finds these bones. Describe (a) your excitement, (b) how, as a scientist, you identify them (carbon dating, assemble a model, compare with other fossils, look for footprints).

Ted Wragg is professor of education at Exeter University.