Knockan Crag National Nature Reserve

This is Knockan Crag, and it is where one of the great puzzles of geology was solved.

Here the rocks are in the wrong order. Moine schist, close to a billion years old, lies on top of limestone and quartzite laid down only about 500 million years ago. For years geologists argued over how, until in the 1880s Benjamin Peach and John Horne showed that the collision of two continents had pushed the older rock up and over the younger along a great fault, the Moine Thrust.

The open-air Rock Room, under a turf roof, tells the story, and bronze figures of Peach and Horne sit by the path looking out over the lochs and peaks of Assynt. The Thrust Trail, about half an hour, leads to the very place where the two rocks meet; the Crag Top Trail makes an hour's circuit with a few steep climbs and a wide view.