Caw. XVIII.] THE SURFACE OF THE EARTH. 199 



tains, but tlie whole continent has fallen away from 

 beneath you, and there now lies below you one vast 

 expanse of water. The water is deep ; but below 

 there is a hard stratified ground, beneath which the 

 interior of the earth is in a state of liquid heat, 

 but gradually cooling ; and, as it cools, the hardened 

 surface is compelled to bend in graceful curves, in 

 order to suit the decreasing size of the globe. By 

 this bending, the water becomes of unequal depths, 

 deepening in parts as it becomes shallow in other 

 parts. At length, immediately below you, a ridge of 

 dry land appears — this, then, is the birth of the 

 South American continent — it continues gradually to 

 rise, throwing off the water to the east and west ; 

 there, then, lies the Pacific, and there the Atlantic 

 Ocean. The bending upwards and downwards, in 

 the same easy graceful curves, continues as long as 

 the surface remains sufficiently pliant ; but at length, 

 becoming more hard and brittle, as the strain still 

 continues, it cracks with a tremendous crash, the 

 rent extending north and south, almost from pole to 

 pole. Up to this moment the surface has yielded 

 gradually to the power of gravitation, offering great 

 resistance. But, once broken, this resistance is gone, 

 and gravitation, acting with unchecked power, crushes 

 and ^grinds the broken edges together with a force 

 scarcely conceivable by the mind of man. Enormous 

 masses of what had once been horizontal strata are 

 now perpendicular, or even reversed. The smashing 



