176 THE SCIENCE OF BIOLOGY 



of attack. It gave the final blow to the doctrine of catas- 

 trophism by showing that there had been no catastrophies. 

 Great changes had occurred, but they had been orderly even 

 when they were most violent. Unconformity in the layers 

 was as much the result of orderly change as was conformity. 



Lyell's position as a Uniformitarian in Geology 18 inclined 

 him to disbelieve the theory of the transmutation of species. 

 He offered what was the final convincing proof of geologic 

 evolution as the historical process by which the crust of 

 the earth had assumed its present form, and he firmly es- 

 tablished the Huttonian doctrine of interpreting the geo- 

 logic past by means of the present. We have seen that the 

 feature of progression in the fossil record had necessitated 

 modification of the idea of a single creation. But with the 

 overthrow of catastrophism by uniformitarianism, the 

 evidence for progression was temporarily ignored. Belief 

 that geologic forces had been constant was conducive to 

 belief in the constancy of species. Even Lyell did not ac- 

 knowledge facts, which were evident in his time and have 

 since become cardinal features in palaeontology, until they 

 were convincingly stated by Charles Darwin in the " Origin 

 of Species." 



The period between 1830 and 1859 has been commonly 

 represented, by the historians of organic evolution, as one 

 in which biological science hesitated to accept the evolution- 

 ary hypothesis because of lack of evidence. The acceptance 

 of evolution, which followed the appearance of the "Origin 

 of Species," seems dramatic, because the impression has been 



18 The "Uniformitarians" opposed the "Catastrophists," pushing Hutton's 

 doctrines to an extreme, by arguing that the action of geological agencies in the 

 past had been so uniform as to preclude anything widely different from the 

 present. "They were inclined to disbelieve that the stratified formations of 

 the earth's crust furnish conclusive evidence of a gradual progression, from 

 the simplest types of life in the oldest strata to the most highly developed in 

 the youngest; and saw no reason why remains of the higher vertebrates should 

 not be met with among the Palaeozoic formations." Geikie, Archibald, Enc. 

 Brit., Article on Geology. 



