12 THE THEORY OF EVOLUTION 



suggested alternative hypotheses to explain the ob- 

 served facts. On the other hand, he seems to have 

 himself believed in the creations and his contem- 

 poraries and successors accepted that doctrine as 

 his. 



Lyell reverted to the neglected teachings of the 

 Scotchman, James Hutton (1728-1797), that the key 

 to the past history of the earth was to be found in 

 the work of agencies which are now in operation. 

 Like Hutton, he would not admit that any process 

 which is not still at work could be called upon to 

 explain events in the past and he even went so far as 

 to make these existing processes the measure and 

 standard of former operations. In the sharpest con- 

 trast to Cuvier's Catastrophism, LyelPs theory was 

 that of Uniformitarianism, which insisted upon the 

 uniformity and complete continuity of the earth's 

 history and of the agencies which had wrought such 

 profound changes upon and within the globe. In the 

 early editions of his famous "Principles of Geology," 

 Lyell was evidently on the point of accepting the 

 theory of organic evolution, but later he receded 

 from this position, because he was not satisfied with 

 the evidence for it. Lyell 's influence upon geology 

 was rapid and profound in England and Darwin, who 

 became his intimate friend, was conspicuously under 

 that influence, as he himself repeatedly testified. 

 One might almost say that Darwin's work largely 

 consisted in the application of Lyell's principle to 

 the world of living beings. 



