402 



GEOLOGICAL SUCCESSION OF ANIMALS. 



conclude that the climate was much more uniform than at 

 the present day. Among the aquatic population, no sound 

 was heard. All creation was then silent. 



670. THE SECONDARY AGE. Reign of Reptiles. The 

 Secondary age displays a greater variety of animals as well as 

 plants. The fantastic forms of the palaeozoic age disappear, 

 and in their place we see a greater symmetry of shape. The 

 advance is particularly marked in the series of vertebrata. 

 Fishes and a few reptiles are no longer the sole representatives 

 of that department. Reptiles, birds, and mammals succes- 

 sively make their appearance, but reptiles preponderate, par- 

 ticularly in the Oolitic formation ; on which account we have 

 called this age the Reign of Reptiles. 



671. The Carboniferous formation is the most ancient of 

 the Secondary age. Its fauna bears, in various respects, a 

 close analogy to that of the palaeozoic epoch, especially in 

 its Trilobites and mollusca.* Besides these, we meet here 



b 



a 



f 



ft d C y 



Fig. 381. The Flora of the coal period. 



a Arborescent fern. d Neuropteris. g Araucaria. 



b Pecopteris. 



c Asterophyllites. 



i 



e Lepidodendron. 

 / Calamites. 



k' 



h Casuerina. 



This circumstance has caused the coal-measures to be generally referred 



