286 SAGACITY AND MORALITY OF PLANTS. 



too frequent metropolitan excavations was being 

 slowly accumulated on a shallow sea-floor. 



For ages before that — indeed ever since the dry 

 land received its first lowly -organised vegetation in 

 Cambrian times — this slow beat of climatic changes 

 has repeatedly taken place. What strange extremes 

 the land -plants must have been subjected to! It 

 is as if the Esquimaux had been repeatedly trans- 

 ported to Calcutta, and the Hindoos forced to take 

 up their abode amidst the eternal frosts and snows 

 of the Arctic regions ! 



It must be further remembered that these 

 climatic variations have been accompanied by 

 equally slow but certain geographical changes, 

 which have converted dry land into sea -bed, and 

 upheaved the bottom of the sea to form new dry 

 lands — which have crumpled up previously hori- 

 zontal strata into tablelands and mountain -chains ; 

 or depressed those already existing until they were 

 let down in the middle like a bellying chain, as is 

 the case with the underground connection between 

 the Mendip and Ardennes Hills, beneath London. 



We can hardly overstate the influence such 

 climatal and physiographical changes must have had 

 upon terrestial floras. As soon as a comparative 

 equilibrium had been set up, and the plants had 

 relatively fought out their battles and yielded to 

 the strongest — as soon as all had more or less 

 adapted themselves to the surrounding physical 



