42 



LINKS WITH THE PAST 



[CH. 



The division of geological history into larger and 

 smaller periods does not imply the recui-rence of 

 sudden revolutions ; it is in some measure dictated 

 by considerations of convenience, but more parti- 

 cularly by our ignorance of certain stages in the 

 history of the world due to the imperfection of the 

 record. 



GEOLOGICAL TABLE. 



Showing the position in the Geological Series of the strata referred 

 to in this volume. 



Superficial accumulations containing human 

 remains (Metal age, Neolithic and Palaeo- 

 lithic ages, Glacial deposits) 



Cromer Forest-bed, etc. 



Absent from Britain. 



Bovey Tracey beds, etc. 



London Clay, etc. 



( Chalk 



I Wealden beds 



( Purbeck and Portland beds (Upper Jurassic) 

 \ Oolites (Middle Jurassic) 

 [ Lias (Lower Jurassic) 



(Rhaetic beds 

 Reuper ,, (Marls with rock-salt, etc.) 

 Bunter „ 



