3 6S CHAPTERS ON EVOLUTION. 



evolution must be held as purely tentative and provisional. The 

 case for evolution, as indicated in our previous studies, is so over- 

 whelmingly strong when we regard the evidence from biology alone, 

 that the evolutionist may well be pardoned if he is inclined to turn a 

 deaf ear to any arguments against his theory which are derived from 

 data so manifestly imperfect in their details as those on which specula- 

 tions concerning past time and life-development are based. 



As bearing in the most intimate manner on this very question of 

 time in relation to evolution, it may be interesting to point out that 

 vast periods of unrepresented time must be allowed for in all con- 

 siderations connected with the past history of the earth. If we 

 tabulate the various fossil-bearing rock-formations in the order in 

 which they occur in nature, the following table will represent their 

 succession : 



KAINOZOIC 



> Miocene. 

 Eocene. 



("Recent Life"). 



Post Tertiary and Recent. 

 Pliocene. 



MESOZOIC f Cretaceous or Chalk. 



PERIOD ] Oolite or Jurassic. 

 ("Middle Life"). I Trias. 



Permian. 

 Carboniferous. 



Devonian > or Old Red Sandstone. 

 ("Ancient Life"). I ^S an (and H uronian). 



V Laurentian. 



This table shows us that the fossil-bearing rocks are arranged in 

 a very definite order and succession ; the lowest, and therefore the 

 oldest, series being the " Palaeozoic " rocks, which in turn possess the 

 Laurentian group as their most ancient formations, and the Permian 

 rocks as their newest. Above these, again, lie the " Mesozoic " 

 rocks, with the Trias, lying above the Permian, as their oldest, 

 and the Chalk, reposing in turn on the Oolite, as their youngest 

 beds respectively. The " Kainozoic " rocks form the last and most 

 recent series of all. They lie upon the Chalk, their oldest strata being 

 those named the Eocene, and their youngest formations the soils and 

 gravels of to-day. It is needless to remark that this tabular order is 

 never anywhere seen in its entirety. Geological revolution dis- 

 turbing the strata, has produced many and serious breaks in their 

 continuity. But such gaps do not affect the order of their succes- 

 sion tabulated by the geologist ; that is to say, the Permian, for 

 example, wherever found, must overlie the Coal, as the latter in turn 

 invariably lies above the Devonian. The complete thickness of the 

 stratified rocks alone or, in other words, their thickness exclusive 



