North Stack North Stack North Stack (Welsh: Ynys Arw, meaning "rugged island") is a small island situated just off Holy Island on the north-west coast of Anglesey. North Stack can also refer to the headland opposite the island. This is the site of a redundant fog warning station, comprising a number of buildings, including the Trinity House Magazine, built in 1861, where shells for the warning cannon were stored. These buildings now house a bird watching observatory, giving a view of South Stack lighthouse across Gogarth Bay, and the studio of artist Philippa Jacobs. The Precambrian quartzite cliffs of this headland, including
St Gwenfaen's Well community of Rhoscolyn in the south west of Holy Island, Anglesey. The well is just under west by south west of the village of Rhoscolyn which is the location of St Gwenfaen's Church, part of the ministry area of Holy Island (Church in Wales). As with much of Holy Island, the well lies within the area of the Glannau Ynys Gybi (Welsh: "Holy Island Coast") Site of Special Scientific Interest and the Anglesey Area of Outstanding Natural Beauty. The remains of the drystone well house are east-west by (originally) north-south. Three steps descend into the building from the east into