Meeting point

On ‘Holy Island’ the geology is mainly Carboniferous limestones (and sandstones with some coal seams) and intrusions of dolerite into the limestones. The Dolerite forms the highest points on what is a very low landscape.
This view shows the intruding dolerite forcing its way up through the limestone. The junction has been heated by the volcanic rock to give a band of metamorphosed limestone. Pretty classical.