394 Professor Agassiz on the Development of Organised Beings 



proved, that the different chains of mountains were elevated 

 successively ; so that at different epochs, the boundaries of the 

 solid land and the ocean must have presented different com- 

 binations. It is also ascertained that in the most ancient pe- 

 riods, the water occupied a much larger extent of the surface 

 than at present ; inasmuch as the most ancient beds in which 

 fossils are found, contain traces of aquatic animals and plants 

 only ; whereas we afterwards meet with immense accumulations 

 of debris of plants indicating a terrestrial flora. These are the 

 plants which are converted into coal. The appearance of ter- 

 restrial animals is still more recent ; for it does not seem to 

 reach a more remote period than the earliest portion of the 

 secondary epoch ; and it is only much later, towards the ter- 

 mination of the cretaceous epoch, and during the tertiary 

 epoch, that the solid land appears to have acquired suffiicient 

 extent, and to have presented differences of level sufficiently 

 great, to admit of the formation of fresh-water lakes. ] 



A very remarkable, and perhaps the most surprising fact, 

 is. that the appearance of the chains of mountains, and the 

 inequalities of the surface resulting from it, seem to have coin- 

 cided generally with the epochs of the renewal of organised 

 beings. Hence, what can be more natural than to suppose 

 that the great diversity of aspect presented by the earth, in 

 consequence of all these changes, was calculated to present to 

 man the most varied conditions of development ? This opinion 

 appears, in some measure, confirmed by the history of the hu- 

 man race, which exhibits to us the development of the most 

 perfect civilization on continents of the greatest diversity of 

 surface, whereas the least intelligent races generally inhabit 

 the monotonous and uniform regions. 



Up to the termination of the tertiary epoch, the law of de- 

 struction was paramount. Man did not then exist. Before 

 his appearance, the earth had once more to undergo dreadful 

 convulsions, which produced the elevation of the greatest 

 chains of mountains. It was only after this last revolution 

 that he was called into existence, along with all the beings 

 which now live with him on the earth ; and thenceforward we 

 find unfolding itself that long history of our race, imposing 

 the laws of its intelligence on the whole of nature. For the 



