Dikes of diorite and gneiss and seams of quartz and feldspar run in every direction. The trap rock yields more readily to the action of the sea than do the granitic rocks, and on being worn away ...

They make up the different landmasses? CONNOR: Yes. There is a rock called Lewisian Gneiss in this area, the oldest rock in Western Europe. The same rock type is found in Canada and Greenland ...

Lewisian gneiss is metamorphic rock, which means it was formed by being heated up and ... They saw a 240-million-year-old rock formed in the Triassic Period, a granite and a glacier erratic – a rock ...