The beautiful model of this most interesting fossil in the British Museum, was presented to me by Baron Cuvier. It is four and a half feet long, and two and a half wide; it consists of the jaws, with teeth, palatal bones, and the tympanic bone, or _os quadratum_, a bone possessed by reptiles, as well as birds, and in which the auditory cells are contained. There are likewise some fine portions of jaws, with teeth, in the British Museum, presented by Camper. The original animal was probably a terrestrial reptile, holding an intermediate place between the Monitors and Iguanas. It was about twenty-five feet long. I discovered, many years since (1820), some vertebræ in the chalk near Lewes, which closely resemble the corresponding bones of the Mosasaurus, and in all probability belong to another species. In the cretaceous strata of New Jersey, Dr. Harlan found and described, and my friend. Dr. Morton, of Philadelphia, sent me, in 1834, teeth which cannot be distinguished from those of Maestricht. Vertebræ, and other bones, have since been obtained from the same deposits by Professor Rogers, and described by Professor Owen in the Geological Journal. XVI. Fossil Reptiles. Although when Mr. Parkinson's work was published many fossil bones and teeth of reptiles had been discovered in various parts of England, yet the abundance and variety, and the extraordinary modification of form and structure of this class of vertebrated animals, which prevailed throughout the secondary geological formations, were not for a moment suspected. The few examples of the remains of fossil reptiles described by Mr. Parkinson, serve to mark the degree of knowledge which then existed respecting a department of palæontology that rapidly acquired an importance and interest unsurpassed by any other branch of fossil osteology. The announcement of the founder of palæontology,[131] that there was a period when the lakes and rivers of our planet were peopled by reptiles, and cold-blooded oviparous quadrupeds of appalling magnitude were the principal inhabitants of the dry land; when the seas swarmed with saurians, exclusively adapted for a marine existence, and the regions of the atmosphere were traversed by winged lizards instead of birds; was an enunciation so novel and startling, as to require all the prestige of the name of Cuvier, to obtain for it any degree of attention and credence, even with those who were sufficiently enlightened to admit, that a universal deluge would not account for the physical mutations which the surface of the earth and its inhabitants had, in the lapse of innumerable ages, undergone. [Footnote 131: In the "Ossemens Fossiles;" tom. v. Reptiles Fossiles.] Subsequent discoveries have established the truth of this proposition to an extent beyond what even its promulgator could have surmised; and the "_Age of Reptiles_" is now admitted into the category of established facts.