Story about a pterosaur

The island was a treasure trove of dinosaurs. We saw many well-preserved pterosaur fossils as we clambered around the cliffs. The caves in the cliffs contained beautiful, prehistoric paintings - mostly antelopes and bison. But one image was clearly intended to represent a pterodactyl. It was impossible that the artist could have seen a living example and we could not make sense of this anachronistic artefact. Until we worked out that painter must have been working from the fossil remains. He or she had reconstructed the dinosaur's appearance and had, in effect, created a story about a pterosaur.