The westernmost headland in the parish of Zennor, near the mouth of the stream which separates Zennor and Morvah, and not far from the villages of Bosigran and Rosemergy, is known as Bosigran Castle. It is fortified on its isthmus by a thick dry-stone vallum. In the centre of the promontory is a large block of granite marked with basins, which is called the Castle Rock; and near this is a large stone scooped, as it were, through the top, known as the Giant's Cradle. A few yards nearer the sea is a logan-rock, over nine yards in circumference, with basins on the top.