This was the third dinosaur to be found and recognized. Again, it was Gideon Mantell who discovered it in Tilgate Forest, in 1832. He said of the discovery
"I venture to suggest the propriety of referring it to a new genus of saurians....and I propose to distinguish it by the name of Hylaeosaurus." (meaning 'Wealden Lizard').
In 1840 Mantell published a different illustration of the same Hylaeosaurus slab, completely redrawn and quite different to his original. Hylaeosaurus was one of the 'founder members' of Owen's 'Dinosauria'.