CHRONOLOGY OF THE EARTH 



B.C. 



Collision between extinct heavenly bodies, and forma- 

 tion of the Nebula . . ... 

 Concentrations in the Nebula, and emergence of the 

 Earth as a molten body . ... 

 Long 1 Ages of intense heat of the whole Earth . 

 Surface of the Earth so far solidified as to support 

 vast seas . . ... 

 Foundational Ages extending over 70,000,000 years, 

 Beginning of Cambrian Period 



Palaeozoic Age 



Mesozoic Age 



Cainozoic Age 



Quaternary Age< 



Ordovician Period 

 Silurian Period . 

 Devonian Period 

 Carboniferous Period 

 Permian Period . 

 Triassic Period . 

 Jurassic Period . 

 Cretaceous Period 



Eocene Period . 

 Oligocene Period 

 Miocene Period . 

 Pliocene Period . 



Pleistocene Period 

 Present Period . 



100,000,000 



30,000,000 



24,500,000 



18,000,000 



15,000,000 



13,000,000 



7,500,000 



7,000,000 



5,750,000 



3,500,000 



2,250,000 



1,750,000 



1,250,000 



400,000 



200,000 

 50,000 



(The estimate of the relative durations of the Periods is founded on the thicknesses of 

 the successive geological strata. All dates are conjectural, and the above duration must 

 be regarded as a minimum.) 



