Marine Cycle of Erosion 1. Youth # The waves are very active. # Sea caves, arches and stalks begin to develop. # Cliff undercutting is pronounced and wavecut platform begins to emerge due to wave erosion. # By the end of youth, an irregular coastline remains. 2. Maturity # The cliff and wave-cut platform are conspicuous. # Stream deposition is taking place. These valleys may be normal or of the hanging type. # Various landforms indicating continuous deposition are visible, such as bars, barriers and spits. 3. Old Age # Irregularities, such as caves and arches disappear.