Geologic Change. 53 



either case the result is plain, and such a one that 

 all must admit that the structure of the earth and 

 all its surroundings justify themselves to reason as 

 a fit provision for such a being as man is. As he 

 progresses in knowledge he not only does better for 

 himself, but he discovers new adaptations of this 

 physical universe to his wants. Every fracture of 

 the rocks, every folding stratum, every vein of met- 

 al, every mineral deposit and every step by which 

 oceans were bounded, mountain chains thrown 

 up, water sheds determined, river channels cut and 

 springs planted among the hills, all these labors 

 of the earth, seem to have been as truly for her 

 children — for every living thing — as the instinctive 

 work of animals is for their young which they pro- 

 vide for, though perchance are never to see. 



Thus far we have spoken of the earth as though 

 caring for organic beings as the mother cares for 

 her children. In all the changes of the earth there 

 have been results that simulate the work of Instinct, 

 and simulate it so closely that many changes in the 

 inorganic world supplement the operations of life, 

 as though the Physical Forces, Physiological Forces 

 and Instinct took counsel together in caring for 

 every living thing, and each took up the task at an 

 appointed time. One responds to the other, and so 

 completely do they do this that it is difficult in all 

 cases to say which we should most admire in the 

 parts they play in carrying on the work. As the 

 young of the animal responds to the parent's In- 

 stinct to secure its aid, so do the various tribes of 

 plants respond to inorganic nature. 



