Moreover, in addition to long shore variations in material strength, it is
important to understand the possible effects of vertical heterogeneity.
For example, as schematised by Trenhaile (2009), cliffs may include
thin beds of more resistant layers, or steeply dipping or horizontally
bedded alternations in material strength. This will affect the dominant
erosional processes, and as sea level rises the strength of the material
being most influenced by marine processes may change.