86 EXTINCT MONSTERS 



do, regard the metamorphosis of the tadpole into a frog as a kind 

 of object-lesson on the part of Dame Nature, given with a view 

 to show us, in a general way and in a short space of time, how 

 the wonderful change from the fish to the reptile took place. 



By the time the great coal-forests of the Carboniferous period 

 were flourishing, the fish class had attained a high state of 

 development, and were to some extent foreshadowing the 

 amphibian type of creation. Now, we know that when the 

 New Eed Sandstone was being laid down, the next great class, 

 viz. the reptiles, had not only made a start, but had struck out 

 in several lines, and were specialised in certain directions, as 

 shown by their bird-like footprints on the Triassic sandstones. 

 Would it not therefore be expected that we should find, in rocks 

 of greater age than the New Eed Sandstone, the remains of 

 animals in some respects intermediate between fishes and 

 reptiles ? This expectation is fully realised by the presence 

 in such strata (i.e. the coal-measures and Permian rocks) of the 

 remains of quite a large number of amphibia. They also crop 

 up again in the Trias, but after that period are not much in 

 evidence until we come to Tertiary times. 



The amphibian class, at the present day, is represented by 

 the frogs, toads, and newts of our own country, and by the 

 salamanders of Japan and the United States. But these are 

 only a meagre remnant of a large number of families that lived 

 ages ago. 



Let us endeavour now to take a general view of the amphibian 

 class as it was in the days of long ago, before the creation of 

 man, to look at their family tree and see what their ancestors 

 were like. When this is done we shall perhaps have a little 

 more respect for the frogs and newts that inhabit our ponds ; 

 for they come of a very ancient stock, and one which played 



