18 Physical Characters of the British Isles 



Fig. 1. The British Isles : showing the distribution of Archasan and 

 Palseozoio (harder) rocks (unshaded), and Secondary, Tertiary and 

 post-Tertiary (softer) rocks (shaded). Glacial deposits are ignored. 

 Comparison with Fig. 2 shows that the great mass of the ground 

 over 500 feet and all of that over 1500 feet is formed of the older 

 rooks. 



