48 



WATER REPTILES OF THE PAST AND PRESENT 



Upper Carboniferous, or Pennsylvanian, however, not only numer- 

 ous 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- 



Fig. 25. — Restoration of Scynwuria, the most primitive of known cotylosaur 

 reptiles. From the Permian of Texas, about two feet long. 



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. 



By the beginning of Permian times tremendous changes had 

 taken place in the land life. The small amphibians of the Car- 

 boniferous 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 



