THE PKESENT. 



ITS FLORA, FAUNA, AND THEIR CO-ADAPTATIONS. 



BEFORE we can rightly compare the Past Life, of which 

 these relics give evidence, with that which now peoples the 

 globe, we must glance at the conditions under which plants 

 and animals at present exist, and know something of their 

 nature and the functions they have to perform. We can 

 only reason respecting the Past from our knowledge of the 

 the Present ; and the more intimate our acquaintance with 

 the various phases of existing nature, the sounder our 

 deductions relating to those that have long since passed 

 away. We say the various phases of existing nature, for 

 the plants and animals that people the surface of any given 

 latitude may differ altogether in character from those en- 

 tombed in the strata beneath, and the organisms in the 

 several formations below may now find their nearest ana- 

 logues in the flora and fauna of distant and diversified 

 regions. If we are familiar, however, with the general con- 

 ditions under which plants and animals now live and 

 flourish, and if we can establish a relationship between 

 those existing and those long since extinct, then we can 

 recall the conditions under which the latter grew and 

 flourished, and map out the geography and climate of the 

 primeval world, as the geographer now maps out the areas 

 of sea and land, and depicts the various races of life the 

 belts of sterility and exuberance and the creative centres 



