From a geological point of view, by far the most important of the Amphibia are the Labyrinthodontia, the distribution of which has just been spoken of. The living orders of Amphibia are of much more modern date, being, with the exception of some not wholly certain Urodelans, wholly Tertiary and Post - tertiary. The Anoura are represented by both Toads and Frogs in Miocene times, and they have survived to the present day. The "Tailed" Amphibians are best known to geologists by a singular fossil, which was described by its original discoverer as human, under the name of Homo diluvii testis. The fossil in question is of Miocene age, and it is now known to belong to a Salamander, nearly allied to the Giant-salamander of Java (Cryptobranchus).

Geinitz has given the name of Palaeosiren to a fossil Amphibian from the Permian, which he believes to be referable to the Urodela. Gaudry, under the title of Salamandrella, has also described certain tailed Amphibians from the Permian, which he believes to be true Salamandroids and not Labyrin-thodonts. The same palaeontologist also suggests that the Carboniferous genera Raniceps and Apateon, instead of being Labyrinthodonts, are really referable to the Urodela, Lastly, no remains of Caecilians have as yet been detected in a fossil condition.