Evolution 



Cretaceous . 



Jurassic 



Triassic 



j Higher mammals 



! { Birds 

 } Marsupials 



I Monotremcs 



REPTILES 



Secondary or 

 Mesozoic, 

 1 1 oer cent. 



Permian 

 Carboniferous 

 Devonian . 

 Silurian 



Cambrian . 

 Laurentian . 



Reptiles 

 Amphibians 

 Lung fishes 

 Lower fishes 



AMPHIBIANS 



FISHES 



Primary or 

 Palaeozoic, 

 32 per cent. 



Archaen, 54 

 per cent. 



FlG. 2. Table showing the chronological succession of the stratified rocks, the sub- 

 division of geological time, the approximate position of the earliest fossils of 

 each of the main types of vertebrates, and the period of domination of each 

 group. 



