The Kimmeridge clay of Weymouth has yielded a huge arm-bone (or humerus), nearly five feet long; and from Wealden strata of Sussex and the Isle of Wight vertebræ have been collected. Altogether we have remains of Cetiosaurus from at least half a dozen counties. Unfortunately, no specimen of a skull has yet been found, and only two or three small and incomplete teeth, which may possibly have belonged to some other animal. Professor Owen estimated the length of the trunk and tail of the creature to have been thirty-five or thirty-six feet; but in the absence of further evidence it was not possible to form any conclusion as to its total length. It is evident that Cetiosaurus was closely allied to the American Brontosaurus (p. 69); and so these earlier English discoveries have gained much in interest from the light thrown upon them by Professor Marsh's huge Saurian. Another English Saurian of this group was the Ornithopsis, from Wealden strata in the Isle of Wight, which has been the subject of careful study by Mr. Hulke and Professor Seeley. Their conclusions, based on the examination of separate portions of the skeleton (such as vertebræ), have been singularly confirmed by the discovery of Brontosaurus. In Ornithopsis the vertebræ of the neck and back, though of great size, were remarkably light, and yet of great strength. One of the vertebræ of the back had a body, or centrum, ten inches long. Hoplosaurus and Pelosaurus were evidently reptiles closely allied to the above types; but at present are so imperfectly known that we need not consider them here. CHAPTER VI. DINOSAURS (_continued_). "Fossils have been eloquently and appropriately termed 'Medals of Creation.'"--Dr. Mantell. When any tribe of plants or animals becomes very flourishing, and spreads over the face of the earth, occupying regions far apart from one another, where the geographical and other conditions, such as climate, are unlike, its members will inevitably develop considerable differences among themselves. During the great Mesozoic period, Dinosaurs spread over a large part of the world; they became very numerous and powerful. Just as the birds and beasts (quadrupeds) of to-day show an almost endless variety, according to the circumstances in which they are placed, so that great and powerful order of reptiles we are now considering ran riot, and gave rise to a variety of forms, or types. Those described in the last chapter were heavy, slow-moving Dinosaurs, of great proportions, and were all herbivorous creatures, apparently without weapons of offence or defence. The group Theropoda, or "beast-footed" Dinosaurs, that partly form the subject of the present chapter, were all flesh-eating animals; and, as we shall discover from their fossilised remains, were of less size, and led active lives. In fact, they acted in their day the part played by lions and tigers to-day.