!8 DARWINISM VERIFIED. [i. 



imaginable, when once the facts of the case have 

 been thoroughly conceived. Looking over the 

 earth's surface to-day, things may seem quiet and 

 stable enough. But if we contemplate the succession 

 of past events, as disclosed by the geologist, what 

 mainly strikes our attention is the secular turmoil. 

 Islands aggregating into continents ; continents break- 

 ing up into archipelagoes ; rivers shifting their beds ; 

 coast-lines changing their direction ; oceans now 

 separated by impassable isthmus-walls, now mingling 

 their floras and faunas through new-made channels ; 

 torrid zones becoming temperate, and temperate 

 zones growing frigid ; marshes transformed into 

 deserts, and glaciated valleys thawing into sunny 

 lakes ; high table-lands sinking into ocean-floors, and 

 submarine ledges rearing their heads as Alpine 

 ranges ; deep-sea molluscs and crustaceans seeking 

 refuge in shallow waters, while littoral organisms 

 migrate upland to find new food and contend with 

 new enemies ; plant-seeds carried by vagrant birds to 

 unwonted habitats ; peaceful tribes of ruminants 

 decimated by invading carnivores ; ceaseless conflict, 

 and redistribution of every possible sort, these are 

 the things we are called upon to contemplate. Re- 

 membering, then, how stability of species is maintained 

 only by the rigorous selection of a few individuals that 



