hNTRODUCTION. 



23 



first occurrence and the present epoch, is enor- 

 mously less than that which had previously elapsed 

 from the time of the oldest stratified rocks. 



It need hardly be observed that in the following 

 table, as in all similar tables, the oldest strata 

 are those which are placed at the bottom. The 

 Archaean or Eozoic rocks contain the earliest organic 

 remains known to exist, and such remains become 

 more and more numerous as we ascend the scale. 

 It is in accordance with the general character of 

 these remains that the rocks are subdivided into 



the systems mentioned in the table, but it is not 

 till we come to the rocks classed as " Recent " tiiat 

 we meet with any subdivision based on the char- 

 acter of the Mammalian remains. The rocks or 

 deposits so termed arc distinguished from the 

 Pleistocene, or those forming the other member of 

 the Quaternary series, by the fact that in them all 

 the mammals belong to species still living, while 

 the latter contain the fossil remains of many ex- 

 tinct mammals, as well as others derived from 

 forms surviving at the present day. 



GEOLOGICAL TABLE, 



SHOWING IN ASCENDING ORDER THE MAIN ROCK-SYSTEMS INTO WHICH THE CRUST 



OF THE EARTH IS DIVIDED. 



Post-Tertiary or Quaternary, 



Tertiary or Kainozoic, 



Secondary or Mesozoic, 



Primary or Pala;ozoic, . 



Arch^an or Eozoic, ... ... 



( Recent— Alluvium, Peat, &c. 

 ( Pleistocene. 

 / Pliocene. 

 < Miocene. 

 V. Eocene. 



(Cretaceous. 

 I Oolitic. 

 ^ Jurassic. } ■, ■ 

 \ •' } Liassic. 



V Triassic. 

 ■ Permian. 

 Carboniferous. 



Devonian and Old Red Sandstone. 

 Silurian. 

 Cambrian. 

 Fundamental Gneiss. 



