Salisbury Crags, Edinburgh

The cliff face of Salisbury Crags looks down on Edinburgh like a grand fortress. Situated in Holyrood Park, less than a half-mile (1 km) southeast of Princes Street, the Crags represent the glaciated remains of a Carboniferous sill, injected between sedimentary rocks which formed in a shallow sea some 340 million years ago. Glaciers sweeping outwards from the centre of Scotland have left a classic crag-and-tail, descending gently towards Arthur's Seat and Whinny Hill in the East. Salisbury Crags are of great significance in the development of modern geology. At Hutton's Section, the Edinburgh geologist James Hutton (1726-97) recognised that the rock now forming the Crags had been injected in a molten state. He was able to use this evidence to disprove the suggestion of the influential German, Abraham Werner, that all rocks had crystallised from a supposed primordial sea