Knockan Crag

Tweet

The road heading north from Ullapool, in the North-West Highlands of Scotland, passes beneath a mile-long cliff that dominates the landscape. This is Knockan Crag, which tells a violent story that dates from before the time of the dinosaurs. The rocks that form this part of the British Isles are extremely old, dating back more than 1,000 million years. They comprise a complex mixture of ancient sedimentary layers and igneous and metamorphic rocks that were laid down during periods of intense volcanic activity. They are also the result of the collision of ancient continents, and that is what can be seen at Knockan Crag, where older rocks overlie younger ones, which logic suggests should be impossible. Some 400 million years ago an event known to geologists as the Moine Thrust took place. Deep underground, a layer of schist - a medium-grade metamorphic rock – was thrust over the top of younger quartzite and limestone rocks. Over millions of years, further earth movements and erosion by wind and rain exposed the Thrust to the surface, as can be seen today. Today, Knockan Crag is a National Nature Reserve with well-marked paths and observation points. As well as being able to look at very old rock formations at close hand, visitors can see rare plants and animals, catch a glimpse of golden eagles wheeling overhead, and look across a vast, barren landscape of lakes, moors and mountains that has seen little change for an unimaginably long period of time.