THE COMING OF EVOLUTION 203 



to Edinburgh, laid the foundations of the modern 

 science of geology. Hutton saw that processes able 

 to produce stratified rocks and to embed fossils there- 

 in were still going on in sea, river and lake. " No 

 powers," said Hutton, " are to be employed that 

 are not natural to the globe, no action to be admitted 

 of except those of which we know the principle" a 

 true precept of science, to avoid the framing of all 

 unnecessary hypotheses. 



Nevertheless, Hutton's " uniformitarian theory " 

 was not generally accepted till William Smith had 

 assigned relative ages to rocks by noting their 

 fossilized contents ; till Georges Cuvier had recon- 

 structed the extinct mammalia of the district from 

 fossils and bones found in the Paris area ; till Jean 

 Baptiste de Lamarck had made a classification and 

 comparison of recent and fossil shells ; and finally 

 till Sir Charles Lyell had collected all available evidence 

 bearing on the manner and extent to which the earth is 

 still being moulded into new forms by water, volcanoes 

 and earthquakes, as well as all known facts about 

 fossils, into his Principles of Geology, first published in 

 1830-3. The cumulative effect of long-continued pro- 

 cesses was then fully grasped for the first time ; and the 

 possibility was realized of tracing the history of the 

 earth, at any rate throughout its habitable ages, from 

 the record of the rocks, by inferences based on obser- 

 vation of operations that were still taking place. 



The problem of the age of man is one of special 

 interest to the human race. The discovery of flint 

 implements, such as are still in use among primitive 

 peoples, and of carved pieces of bone and ivory, in 

 conjunction with the remains of animals that are 



