coasts-formation of stacks

a headland contains small cracks in the clifface

hydraulic action causes the crack to enlarge and become more suseptible to other types of erosion such as abraision

this constant erosion will go on for a long time until it forns a cave

the headland will have caves on both sides and they will erode inwards toward each other until they breack through forming an arch

erosion will continue to happen of the base of the arch causing continuous rock falls until the sides can't support the roof and it will collapse forming a stack

the base of the stack will continue to be eroded until it can't support it's own weight and collapses forming a stump away from the headland