

36 



Evolution 



A SIMPLE GEOLOGICAL SCALE 



Epoch 



Period 



Relative 

 age 



Types of animal life 

 that appear 



Quaternary 

 (actual) 



Holocene 

 Pleistocene 



years 

 500,000 



Neolithic & modern 



man. 

 Paleolithic man. 



Tertiary 



Pliocene 



Miocene 



Oligocene 

 Eocene 



5,500,000 



Ape-men of Java. 



Anthropoid apes, 

 apes, norse, camel, 

 hog, elephant, ox, 

 sheep, rhinoceros, 

 etc. 



Lemurs, early horse, 

 whale, etc. 



Secondary 



Cretaceous 

 Jurassic 

 Triassic 



7,200,000 

 3,600,000 

 2,500,000 



Toothed birds, bony 



fishes. 

 Crab, higher insects, 



crocodile, flying 



reptiles, archaeop- 



teryx. 

 Monotremes and 



marsupials. 



Primary 



Permian 

 Carboniferous 



Devonian 



Silurian 

 Ordovician 



Cambrian 



I 9,000,000 



8,000,000 



5,400,000 

 5,400,000 



8,000,000 



Reptiles. 

 Amphibia. 

 Fishes — elasmo- 



branchs, dipnoi, 



and ganoid. 

 [Insects, ostraco- 

 j derms,cephalopods. 

 Rhizopods, sponges, 



corals, worms, 



Crustacea, hydro- 



zoa. 



Archaean 



Prc-Cambrian 



indefinite 





Note. — The above table is simplified for the purpose of this 

 work. The age is assigned approximately (from the thickness 

 of the strata) on a scale of fifty-five million years for the 



stratified rocks. 



