"Collecting a pile of fossils is only the beginning. Many fossils are only fragments of the whole animal or plant. To piece together the whole organism is rather like doing a jigsaw puzzle without the benefit of the complete picture to work towards. Piece has to be added to piece, and the larger and more fragmentary the animal the more the result is in question. Not surprisingly mistakes have been made. The first reconstruction of the dinosaur Iguanodon finished up with its thumb on its nose!"