Types of shingle structure

Once the shingle beach is raised, through the deposition of material, above the height of normal waves, shingle structures begin the develop. These are larger than shingle beaches and in time become more terrestrial in nature. They occur in two basic forms:

1. Cuspate forelands develop when shingle is available in large quantities and piles up in front of fringing beaches or spits and is then driven landwards by storm waves to form apposition beaches. If this process is repeated, a series of roughly parallel ridges may develop and an extensive area of stable shingle results. Where wave approach can be from two directions only, such apposition beaches will form into cuspate forelands;
2. Large masses of shingle may also form offshore barrier islands under conditions of shallow water and low energy environments such as in the North Sea and the Baltic. In practice it is often impossible to treat these features as separate entities as they are frequently intricately linked with dune or saltmarsh habitats.