The circumstance that in several individuals the substance of the wing membrane is preserved would appear to indicate either that it was exceptionally stout when there would have been small chance of resisting decomposition, or that its preservation is due to a covering which once existed of fur or down or other clothing substance, which has proved more durable than the skin itself. [Illustration: FIG. 48. REMAINS OF DIMORPHODON FROM THE LIAS OF LYME REGIS SHOWING THE SKULL, NECK, BACK AND SOME OF THE LONGER BONES OF THE SKELETON _From a slab in the British Museum (Natural History)_] CHAPTER XIII ANCIENT ORNITHOSAURS FROM THE LIAS Cuvier's discourse on the revolutions of the Earth made the Pterodactyle known to English readers early in the nineteenth century. Dr. Buckland, the distinguished professor of Geology at Oxford, discovered in 1829 a far larger specimen in the Lias of Lyme Regis, and it became known by a figure published by the Geological Society, and by the description in his famous Bridgewater Treatise, p. 164. This animal was tantalising in imperfect preservation. The bones were scattered in the clay, so as to give no idea of the animal's aspect. Knowledge of its limbs and body has been gradually acquired; and now, for some years, the tail and most parts of the skeleton have been well known in this oldest and most interesting British Pterodactyle. Sir Richard Owen after some time separated the fossil as a distinct genus, named Dimorphodon; for it was in many ways unlike the Pterodactyles described from Bavaria. The name Dimorphodon indicated the two distinct kinds of teeth in the jaws, a character which is still unparalleled among Pterodactyles of newer age. There are a few large pointed, piercing and tearing teeth in the front of the jaws, with smaller teeth further back, placed among the tearing teeth in the upper jaw; while in the lower jaw the small teeth are continuous, close-set, and form a fine cutting edge like a saw. [Illustration: FIG. 49. LEFT SIDE OF DIMORPHODON (RESTORED) AT REST]