80 DOCTRINE OF EVOLUTION 



the earth's history. Although he saw that animals of 

 successive periods displayed similar structures, like 

 the skeleton of vertebrates, which testified to some 

 connection, Cuvier could not bring himself to believe 

 that this connection was a genealogical one. 



Mainly through the influence of the renowned Eng- 

 lish man of science, Charles Lyell, the students of the 

 earth came to the conclusion that its manifold struc- 

 tures had developed by a slow and orderly process that 

 was entirely natural ; for they found no evidence of any 

 sudden and drastic world-wide remodeling such as that 

 postulated by the Cuvierian hypothesis of catastrophe. 

 The battle waged for many years ; but now naturalists 

 believe that the forces of nature, whose workings may 

 be seen on all sides at the present time, have recon- 

 structed the continents and ocean beds in the past in 

 the same way that they work to-day. The long name 

 of "uniformitarianism" is given to LyelPs doctrine, 

 which has exerted an influence upon knowledge far 

 outside the department of geology. Darwin tells us 

 how much he himself was impressed by it, and how it 

 led him to study the factors at work upon organic 

 things to see if he could discern evidence of a biological 

 uniformitarianism, according to which the past history 

 of living things might be interpreted through an under- 

 standing of their present lives. 



What, now, are the reasons why the palaeontological 

 evidence is not complete and why it cannot be ? In the 

 first place the seeker after fossil remains finds about 

 three fifths of the earth's surface under water so that 



