When are soft rocks tough, and hard rocks weak?

New ELI today - 'When are soft rocks tough, and hard rocks weak? A discussion about the toughness/resistance of rocks in different places'

The simple idea, which generally holds, of tough rocks forming hills and headlands and weaker rocks, valleys and bays, does not always apply. This activity looks for evidence of when and why it is not always true.
Many activities related to rock resistance can be found on our website.