278 THE STORY OP THE EARTH AND MAN. 



came. Slowly and gradually, or by intermittent lifts, 

 the land rose ; and as it did so, shallow- water sands 

 and gravels were deposited on the surface of the deep- 

 sea clays, and the sides of the hills were cut into 

 inland cliffs and terraces, marking the stages of reces- 

 sion of the waters. At length, when the process was 

 complete, our present continents stood forth in their 

 existing proportions ready for the occupancy of man. 



The picture which these changes present to the 

 imagination is one of the most extraordinary in all 

 geological history. We have been familiar with the 

 idea of worlds drowned in water, and the primeval 

 incandescent earth shows us the possibility of our 

 globe being melted with fervent heat; but here we 

 have a world apparently frozen out — destroyed by 

 cold, or doubly destroyed by ice and water. Let us 

 endeavour to realise this revolution, as it may have 

 occurred in any of the temperate regions of the 

 Northern Hemisphere, thickly peopled with the 

 magnificent animals that had come down from the 

 grand old Miocene time. Gradually the warm and 

 equable temperature gives place to cold winters and 

 chilly wet summers. The more tender animals die 

 out, and the less hardy plants begin to be winter- 

 killed, or to fail to perfect their fruits. As the forests 

 are thus d'^cimated, other and hardier species replace 

 those which disappear. The animals which have had 

 to confine themselves to sheltered spots, or which 

 have perished through cold or want of food, are re- 

 placed by others migrating from the mountains, or 



