The animal to which the name _ichthyosaurus_ has been given, was as long as a young whale, and it was fitted for living in the water, though breathing the atmosphere. It had the vertebral column and general bodily form of a fish, but to that were added the head and breast-bone of a lizard, and the paddles of the whale tribes. The beak, moreover, was that of a porpoise, and the teeth were those of a crocodile. It must have been a most destructive creature to the fish of those early seas. The _plesiosaurus_ was of similar bulk, with a turtle-like body and paddles, shewing that the sea was its element, but with a long serpent-like neck, terminating in a saurian head, calculated to reach prey at a considerable distance. These two animals, of which many varieties have been discovered, constituting distinct species, are supposed to have lived in the shallow borders of the seas of this and subsequent formations, devouring immense quantities of the finny tribes. It was at first thought that no creatures approaching them in character now inhabit the earth; but latterly Mr. Darwin has discovered, in the reptile-peopled Galapagos Islands, in the South Sea, a marine saurian from three to four feet long. The _megalosaurus_ was an enormous lizard—a land creature, also carnivorous. The _pterodactyle_ was another lizard, but furnished with wings to pursue its prey in the air, and varying in size between a cormorant and a snipe. Crocodiles abounded, and some of these were herbivorous. Such was the iguanodon, a creature of the character of the iguana of the Ganges, but reaching a hundred feet in length, or twenty times that of its modern representative. There were also numerous _tortoises_, some of them reaching a great size; and Professor Owen has found in Warwickshire some remains of an animal of the batrachian order, {99} to which, from the peculiar form of the teeth, he has given the name of labyrinthidon. Thus, three of Cuvier’s four orders of reptilia (_sauria_, _chelonia_, and _batrachia_) are represented in this formation, the serpent order (_ophidia_) being alone wanting. The variegated marl beds which constitute the uppermost group of the formation, present two additional genera of huge saurians,—the phytosaurus and mastodonsaurus.