CHAPTER XIV 



SURFACE GEOLOGY 



IN the foregoing pages we have been dealing almost en- 

 tirely with the solid rocks, their structure and behaviour 

 as constituent portions of the earth's crust. Allusions 

 have been made to their superficial aspects and to the 

 loose accumulations of various kinds by which th< 

 so often concealed. In this chapter let us look cursorily 

 at a few of the aspects of what is sometimes called 

 " surface geology." 



And first, of the influence of the solid rocks upon the 

 surface. The distinctive characters imparted by some 

 rocks to scenery have already been referred to. 1 Some- 

 times it is a question of relative durability. The Chalk 

 escarpment in the south of England, for example, stands 

 out so prominently because it is underlain by more easily 

 degraded sands. Certain portions of a rock may rise high 

 above the rest because of some particular power of resist- 

 ance they may happen to possess. But one leading 

 influence in the gradual degradation of all rocks is 

 supplied by their /0iVi/j. Every one who has looked into 

 a quarry or railway cutting, or has seen a coast-cliff or a 

 1 Sec ante, p. 73. 



