CHAPTER XII. 

 PRE-DETERMINATION IN NATURE. 



THE natural prejudice of persons not acquainted with 

 geology is that in the world all things continue as they 

 were from the beginning. But a little observation and experi- 

 ence dispels this delusion, and perhaps replaces it with an 

 opposite error. When our minds have been familiarized with 

 the continuous processes by which vaporous nebulae may be 

 differentiated into distinct planets, and these may be slowly 

 cooled from an incandescent state till their surfaces become 

 resolved into areas of land and water ; and still more, when 

 we contemplate the grand procession of forms of life from the 

 earliest animals and plants to man and his contemporaries, we 

 become converts to the doctrine that all things are in a per- 

 petual flux, and that every succeeding day sees them different 

 from what they were the day before. In this state of mind the 

 scientific student is apt to overlook the fact that there are 

 many things which remain the same through all the ages, or 

 which, once settled, admit of no change. I do not here refer 

 to those fundamental properties of matter and forces and laws 

 of nature which form the basis of uniformitarianism in geology, 

 but to determinations and arrangements which might easily 

 have been quite different from what they are, but which, once 

 settled, seem to remain for ever. 



We have already considered the great fact that the nuclei 

 and ribs of the continental masses were laid down as foundations 

 in the earUest periods, and have been built upon by determi- 



