The Excavation of Castell, Porth Trefadog, A Coastal Promontory Fort in North Wales

Abstract

CASTELL is a promontoryflrton the north-west coast ojAnglesey. The surviving de}tnces wert erectedin or before the f 2tn century A.D. on the ruim ofan earlierfortification and are contemporary with the occupation of a rectangular house or hail. The house was subsequently used for metalworking. The excavation ofCasteLl is described and the possible historical contexts for the fortification ofthe Porth Trtfadog promontory are discussed. Castell is sited on boulder clay capping harder rock forming a promontory immediately to the S. ofthe deeply indented bay of Porth Trefadog on the W. coast of Anglesey (Fig. I). The promontory is the object of erosion by sea and storm; inshore rocks protect the NW. face from direct attack by the sea but the bay is not so protected. Wave action is severely eroding this stretch of coast and has begun to anack the underlying rock on the NE. face of the promontory. A more immediate threat is posed by slumping due to the water content of the soil along the difffaces. The principal surface features of the site are a massive bank ofdump construc­ tion with a deep external ditch defining two landward sides ofa rectangular area of around 225 sq.m. The twO remaining sides ofdifTface are bounded by a slighter but more regular wall incorporating masonry in its construction. The SE. circuit ofditch appears to be a modification ofa natural gulley (Figs. 1 and 2). Masonry is exposed along the length of the NW. cliff edge wall and a length ofthe dump bank had been