Note the ridge in the middle which is a rampart of the headland fortress that once was well-situated for defending itself against enemies. The name 'Treryn Dinas' comes from the Cornish for 'Fortress' (Dinas) [of a] 'Settlement' (Tre) [on] a point of land (rynn). 'Treen' is a shortened form of this also used for the nearby village.
