The strange vagaries of Dinosaurs have led Professor Marsh and other authorities to exalt them, from their former position of a mere order in the reptile class, to the dignity of a sub-class all to themselves; and there is much to be said for this view. Compared with the Marsupials, living and extinct, they show an equal diversity of structure and variations in size from by far the largest land animals known down to some of the smallest.[16] [16] Bauer, after a full critical examination of the Dinosauria, considers that one order is insufficient, and has proposed to make three orders of them, which he names after the Iguanodon, Cetiosaurus, and Megalosaurus. The importance of discovering, if possible, a portion of the jaw of an Iguanodon was fully recognised by Dr. Mantell, and, urged on by the encouragement he had received from the illustrious Cuvier, he eagerly sought for the required evidence. But nearly a quarter of a century elapsed before it was forthcoming. In 1841 and 1848, however, portions of the lower jaw, with some teeth attached, were found; and his memoir _On the Structure of the Jaws and Teeth of the Iguanodon_ was published by the Royal Society in 1848. For this important communication the gold medal of the society was awarded to the author. The second of these finds (by Captain Brickenden) confirmed in every essential particular the inferences suggested by the detached teeth. The first important connected series of bones of this monster was discovered in 1834, by Mr. Bensted, in the "Kentish Rag" quarries of the Lower Greensand formation at Maidstone. Mr. Bensted, who was the proprietor of the quarry, one day had his attention drawn by the workmen to what they supposed to be petrified wood in some pieces of stone which they had been blasting. He perceived that what they supposed to be wood was fossil bone, and, with a zeal and care which have always characterised this estimable man (says Professor Owen) in his endeavour to secure for science any evidence of fossil remains in his quarry, he immediately resorted to the spot. He found that the bore, or blast, by which these remains were brought to light had been inserted into the centre of the specimen, so that the mass of stone containing it had been shattered into many pieces, some of which were blown into the adjoining fields! All these pieces he had carefully collected, and, proceeding with equal ardour and success to the removal of the matrix from the fossils, he succeeded, after a month's labour, in exposing them to view, and in fitting the fragments in their proper place. This valuable specimen was presented to Dr. Mantell (and afterwards purchased with the rest of his collection by the British Museum), and its present condition is the result of his skill, as well as that of its discoverer. Certain gentlemen in Brighton, anxious that the specimen should be placed in the hands of the original discoverer of Iguanodon, purchased and presented it to Dr.