Classic models of the evolution of rocky coasts, like the one below, do not generally reflect the complexity of form on the rocky shorelines on Orkney. This is a reflection of the dominance of hydraulic action over abrasion in coastal erosion and also the variety of coastal configuration on Orkney.
Each of the main landform elements is locally well-developed but the assemblage of all these features is rarely seen. The main types of cliffed coast on Orkney are:
- high, vertical cliffs, with occasional stacks, which plunge into deep water, indented with geos and honey-combed with caves. Examples include The Nev and Quoy Geo.
- high, vertical cliffs with narrow boulder-strewn shore platforms, as around the Old Man of Hoy.
- low, drift-capped cliffs with geos and wide shore platforms but lacking stacks.