THE THEORY OF ORGANIC EVOLUTION 175 



creased as the record was followed backward in time. Con- 

 versely, the fossils of more recent time were in many cases 

 almost identical with existing forms. Evidences of violent 

 geological disturbances were taken to mean that great 

 catastrophies or cataclysms had occurred. By supposing 

 that such cataclysms had destroyed all life and made neces- 

 sary a new creation, it was possible to save the creation 

 theory, since the creation described in Genesis could then be 

 regarded as but the last of a series. The Day of Judgment 

 was the cataclysm which would bring the present epoch to an 

 end. Catastrophism was a step forward, in so far as it 

 acknowledged facts of palaeontology, which were then well 

 established, and emphasized the study of natural forces 

 after the manner which Hutton had laid down. 



Cuvier was the most forceful advocate of catastrophism. 

 His studies upon fossil animals forced him to recognize the 

 progressive sequence of the record, which is now regarded as 

 one of the strongest pieces of evidence for organic evolution. 

 But he approached the subject with preconceived notions 

 that were an inheritance from medieval cosmogony. He 

 was, therefore, opposed to the theory of descent. Eventu- 

 ally the facts of anatomy which he established became 

 important evidence for evolution. 



While the acceptance of organic evolution was thus de- 

 layed, the evolutionary principle was established in geolog- 

 ical science by the work of Charles Lyell (1797-1875). Lyell 

 was not at first a believer in organic evolution, but was con- 

 verted to this view by Darwin's " Origin of Species." His 

 " Principles of Geology" (1830) was widely read and studied. 

 It maintained its place as an authoritative reference work 

 until the last quarter of the nineteenth century. The sig- 

 nificance of this book is found in the fact that it attempted 

 to explain the past in terms of the present after the manner 

 characteristic of modern geology. Its sub-title, ' ' An Attempt 

 to Explain the Former Changes of the Earth's Surface by 

 Reference to Causes now in Operation," indicates the manner 



