ANIMALS OF LONG AGO 343 



probably the dwarfed descendants of gigantic Carboniferous 

 ancestors ; and our valuable coal seams have been formed from the 

 vegetation of this period. A fact of the greatest interest is the appear- 

 ance of remains of Amphibians in the Carboniferous rocks. To this 

 class belong Toads, Salamanders and Frogs, but the Amphibians 

 of Carboniferous times were rather different from their modern repre- 

 sentatives, and much more numerous in species. They are termed 

 Labyrinthodonts, a name given to their kind on account of their 

 peculiar teeth, which have a curiously complicated structure somewhat 

 after the nature of a labyrinth. Labyrinthodont means "labyrinth- 

 toothed." The Amphibia originating in Carboniferous times per- 

 sisted into later periods, the Permian and Triassic ; they varied in 

 size from an inch or two to seven or eight feet. They tenanted the 

 coal-forests of America and Europe and must have spent a large part 

 of their existence in the extensive marshes of their time. 



The Permian rocks succeed the Carboniferous, and are of the 

 comparatively moderate thickness of about 1,500 feet. They get their 

 name from the province of Perm in Russia, where they are well 

 developed; indeed, they appear over the greater part of European 

 Russia. They are also developed in India, Southern Africa, New 

 South Wales, Texas and Kansas. The Trilobites, first found in 

 Cambrian rocks, persisted up till Permian times and then dis- 

 appeared. Great amphibia abounded in the marshes and ganoid fish 

 still existed. With the Permian rocks the Primary or Palaeozoic 

 Epoch is terminated. 



The Secondary or Mesozoic Epoch comprises the Triassic, 

 Jurassic and Cretaceous Systems. 



The Triassic system covers rocks of about 3,000 feet in thickness, 

 including the New Red Sandstone. The remains of Labyrinthodonts 

 still occur, even the impressions of their footprints being in some 

 instances preserved. The chief interest of the Triassic rocks to the 

 student of extinct animals, however, is the existence in them of 

 remains of what are known as Theromorphic Reptiles, so named 

 because in some characteristics of their jaws and skulls they resemble 

 the Theria or Mammals ; indeed, they seem to be an approach to that 

 point in the development of backboned animals from which Amphib- 

 ians, Reptiles and Mammals have branched off. Their remains have 

 been discovered in Triassic rocks in Scotland, India, South Africa 

 and Russia. One of these Theromorphs known as the Pareiasaurus 

 (Greek, "surpassing a reptile") is represented by a reconstructed 



