CHAPTER XLIII. 

 PHYSICAL GEOGRAPHY. I. GEOLOGY. 



GEOGRAPHY AND GEOLOGY THE EARTH'S CRUST ORIGIN OF THE EARTH 



DENUDATION AND EXCAVATION BY WATER ROCKS, GRAVEL, AND 



SAND CLASSES OF ROCKS. 



WHEN we were at school, and learnt the various countries of Europe, we 

 had maps showing us the several divisions of one realm from another ; the 

 mountains, lakes, and other prominent features of the continent were learned 

 and repeated, but we, maybe, seldom, perhaps never, bestowed a thought 

 upon the formations of the mountains, and the manner in which rivers ran 

 down into and through lakes to the ocean. There were the mountains, there 



Fig. 636. Cliffs worn by the sea. 



were the lakes and rivers, and capes, and headlands, and there they are still, 

 to all intents and purposes, the same to see, to climb up, to sail down, as 

 the case may be. But the map of Europe has undergone a visible change. 

 Territory has changed hands. Germany has gripped France, England has 

 got Cyprus, Turkey has been dismembered, and Austria is annexing territory. 

 This study is called Geography, POLITICAL GEOGRAPHY, for it marks the 

 political boundaries. The knowledge of the formation of hills, headlands, 

 lakes, rivers, seas, their causes, constitution, and effects, how they rose, 



