284 Theories of Evolution and Creation 



evidences of the cataclysms, nor into the mechanism of the 

 successive creations. At one time Cuvier surmised that 

 these cataclysms might perhaps not have been universal in 

 extent. The repopulation of an area might then result from 

 migrations out of unaffected regions. This thought, how- 

 ever, he could not maintain consistently for there still re- 

 mained to explain his own doctrine of progressive succession 

 of higher and higher forms. 



JJniforTnitarianism 



During the year in which Cuvier debated before the 

 Academy of Sciences with Saint-Hilaire (1830) there ap- 

 peared in England an important book by Charles Lyell, The 

 Principles of Geology. Lyell took his cue from James 

 Hutton, a Scotchman of the Eighteenth Century, who ap- 

 proached the problems of geology with a rather fresh mind. 

 He insisted, in effect, that the structures and formations of 

 the earth's crust be interpreted in terms of known forces 

 operating in our own times in known ways. In other words, 

 we should treat the problems of geology as nearly as possible 

 as matters of fact and not by means of unfounded specula- 

 tions. Lyell applied Hutton's thought by actually studying 

 the processes by which rocks are weathered, soils are eroded, 

 silts are deposited, gulleys are cut by rivers, dead animals 

 are buried by mud, and so on. This was a projection from 

 the known to the unknown. It took in this case the in- 

 evitable form of assuming that the forces today at work in 

 making and remaking the crust of the earth were at work 

 yesterday and all through the past. It meant that the known 

 forces were sufficient to account for the facts as presented 

 by the crust of the earth and its inclusions. It meant that 

 there was no need to assume other types of agencies to ex- 

 plain what has happened in the past. 



These principles were based upon a study not only of 

 the earth in its static phases, so to say, but also of the dy- 

 namic events that are in our own time reshaping the earth. 



