Headlands and bays are often found on the same coastline. A bay is
surrounded by land on three sides, whereas a headland is surrounded
by water on three sides. Headlands are characterized by high, breaking
waves, rocky shores, intense erosion, and steep sea cliffs. Bays generally
have less wave (and often wind) activity than the water outside the bay,
and typically have sandy beaches. Headlands and bays form on
coastlines, where there are alternating outcrops of resistant(harder)
and less resistant(softer) rock.
Due to the presence of soft and hard rock, erosion occurs, with
the soft, less resistant rock (e.g. shale), eroding quicker than the
hard, resistant rock (e.g. chalk)Where the erosion of the soft
rock is rapid, bays are formed. Where there is more resistant
rock, erosion is slower and the hard rock is left sticking out into
the sea as a headland. The exposed headland now becomes
vulnerable to the force of destructive waves but shelters the
adjacent bays from further erosion.