Worm’s Head is a narrow, tidal island, joined by a causeway to a *promontory on the south side of Rhossili Bay, and it forms the westernmost point of the Gower Peninsula. Like the smaller island on the north side of the bay (Burry Holms), the headland is formed of relatively resistant carboniferous limestone; the intermediate rocks, along the three-mile bay, are softer Old Red Sandstone and hence these have eroded more quickly, leaving the exposed spurs at either side.

The promontory is a flat-topped area about 175 feet above the sea, at the level of an ancient beach, and is partly lined by cliffs but slopes down less steeply at the far side to a band of exposed rocks along the shoreline, separated at high tide by a quarter of a mile of open water from the island, which was so named due to its long, slender, serpentine outline, ‘wyrm’ being an ancient term for a dragon.

The island has four distinct sections — the nearest and largest is the Inner Head, an oval-shaped area rising up to 140 feet, connected by another rocky belt, occasionally breached by storm tides but otherwise above the high water mark, to the much smaller Lower Neck, which adjoins the Middle Head. These two are separated by Devil’s Bridge, a large, angular opening beneath a narrow strip of rock. The most distant section of the island, the Outer Head, is also the highest, ending at a small summit about 150 feet high. Like most of the island, Outer Head is bordered by sheer cliffs to the north but the south side is more gently sloping, and a wide band of intricately eroded limestone formations is revealed when the tide recedes, enhancing the already very photogenic scenery.

*promontory: a narrow area of high land that sticks out into the sea