CHAPTER XI 



HOW SOIL HAS BEEN MADE 



Apparatus required. 



The apparatus in Fig. 54. The under surface of 

 the lips of the heahers should he vaselin^d to prevent 

 the water tricMing down the sides. 



It is not uncommon to find cliffs or crags in inland 

 places, but they usually show one very striking difference 

 from seaside cliffs. The seaside cliffs may be nearly 

 vertical, but the inland cliffs are not, excepting for a 

 little way at the top ; lower down a heap of stones and 

 soil lies piled against the face of the cliff and makes a 

 slope up which you can climb. If you look at the cliff 

 you can find loose fragments of it split off either by the 

 action of freezing water (p. 83) or by other causes ready 

 to roll down if sufficiently disturbed. So long has this 

 been going on that a pile has by now accumulated, and 

 has been covered with plants growing on the soil of the 

 heap. Our interest centres in this soil ; no one has 

 carried it there; it must have been made from the 

 rock fragments. When you get an opportunity of 

 studying such a heap, do so carefully ; you can then 

 see how, starting from a solid rock, soil has been formed. 

 This breaking down of the rock is called weathering. 



The same change has gone on at the top of the 

 cliff. Fragments have split off and the rock has broken 



