In the rocks of the next great time division, the Mississippian, as we call it in America, corresponding more or less closely with the Lower or Subcarboniferous of other parts of the world, numerous footprints of amphibians have been discovered, but no fossil remains except a few from near its close in Scotland. From the Upper Carboniferous, or Pennsylvanian, however, not only numerous footprints but the actual skeletons, or impressions of skeletons, have long been known in Europe and America. Until recently all these footprints and skeletons were supposed to be exclusively amphibian. We are now almost sure that some of them belonged to reptiles of lowly type, the earliest coming from near the middle of the Pennsylvanian of Linton, Ohio. The amphibians of this period were, for the most part, salamander-like creatures of from a few inches to two or three feet in length. They all belong to the group collectively known as the Stegocephalia, except that very near the close of the period there appeared small, slender, small-legged aquatic forms which seem to be the ancient representatives of the real salamanders of modern times. Some of the Stegocephalians had become greatly specialized as legless, snake-like, or eel-like creatures. [Illustration: FIG. 25.—Restoration of _Seymouria_, the most primitive of known cotylosaur reptiles. From the Permian of Texas, about two feet long.] By the beginning of Permian times tremendous changes had taken place in the land life. The small amphibians of the Carboniferous types dwindled away, soon to disappear, and their places were taken by others of peculiar types, for the most part larger; and by many and diverse kinds of reptiles—water reptiles, marsh reptiles, land reptiles, and even climbing tree reptiles. From the uppermost Carboniferous and Lower Permian rocks of the United States more than fifty genera and twice that many species of amphibians and reptiles have been made known in recent years, and doubtless as many more will be discovered in the future. From other parts of the world the history of reptiles of the Lower Permian is yet scanty, two or three forms from South America, as many more from Africa, and a half-dozen or so from Europe are all; and of these very few are known at all well. [Illustration: FIG. 26.—_Captorhinus_, a cotylosaur reptile from Texas.]