Evolution of tJif Earth. 95 



It was formerly the accepted opinion that the great 

 •changes on the earth's surface had been mainly brought 

 about by these cataclysmic agencies. Sir Charles Lyell, 

 however, and the leading geologists of the modern school, 

 have made it clear that the great geological changes have 

 been produced slowly, by gradual processes of subsidence 

 and elevation, and not by earthquakes and volcanic action. 

 Compared with the slow evolutionary movements of Na- 

 ture, cataclysm or revolution has played but a small part 

 in our mundane affairs. Volcanic action and earthquakes 

 are merely the culminations of orderly and gradual an- 

 terior processes. 



I cannot do better than to close this branch of the 

 subject with a quotation from Professor Le Conte, a master 

 in this field of thought and investigation : — 



"There was a time (not many decades ago) when all 

 things, the origin of which transcends our ordinary expe- 

 rience, were supposed to have originated suddenly and with- 

 out natural process — to have been made at once, out of 

 hand, There was a time when, for example, mountains 

 were supposed to have been made at once, with all their di- 

 versified forms, of beetling cliffs, and thundering water- 

 falls, or gentle slopes and smiling valleys, just as we now 

 find them. But now we know that they have become so 

 only by a very gradual process, and are still changing under 

 our very eyes. In a word, they have been formed by a pro- 

 cess of evolution. We know now the date of mountain- 

 births ; we trace their growth, maturity, decay and death ; 

 and find even, as it were, the fossil bones of extinct moun- 

 tains in the crumpled strata of their former places. There 

 was a time when continents and seas, gulfs, bays and rivers, 

 were supposed to have originated at once, substantially as 

 we now see them. Now we know that they have been 

 changing throughout all geological time, and are still chang- 

 ing. Not, however, changing back and forth in any direc- 

 tion indifferently and without goal, but gradually changing 

 from less perfect to more perfect condition, with more and 

 more complex inter-relations — i. e., by a process of evolu- 

 tion. There was a time when rocks and soil were supposed 

 to have been always rocks and soil ; when soils were regard- 

 ed as an original clothing made on purpose to hide the rocky 

 nakedness of the new-born earth. God clothed the earth 

 so, and there was an end. Now we know that rocks rot 



