Cliffs are shaped through a combination of erosion and weathering. The erosive forces of hydraulic action and abrasion as well as the processes of weathering, such as freeze-thaw and carbonation, can contribute to cliffs retreating. Soft rock, such as clay, erodes easily to create gently sloping cliffs whilst hard rock erodes slowly to create steep cliffs.Wave-cut platform formation starts with sub-aerial processes weakening the top of the cliff. The cliff base is attacked by forces of erosion, such as abrasion, causing a wave-cut notch to form. Overtime the cliff collapses, partially due to its weakened state as well as under gravity because the top of the cliff has been left unsupported as the notch increases in size. This process repeats, eventually leaving behind a wave-cut platform as cliff retreat continues.