Caithness: where the castle meets the cliff

At Castle Sinclair Girnigoe, I take guests to the fenced edge of the coast, where we can look across at the castle walls meeting the rock beneath them. What catches people’s attention is how difficult it can be to distinguish one from the other, because the masons were working with the same layered material on which their building stands. Follow those layers away from the masonry and you can see how much of the arrangement was already there, long before anyone thought of building a castle. To explain that, I have to take us back roughly 390 million years and replace the sea before us with a lake.

Scotland then lay south of the equator, with much of present-day Caithness and Orkney belonging to a lake system known as Lake Orcadia. Rivers brought sand and finer material into its waters, gradually covering the bottom as the shoreline shifted with the changing climate. Sometimes the water retreated far enough to leave mud drying and cracking beneath the sun, while deeper areas received delicate layers of sediment. Over millions of years, the weight of further deposits compressed the material below, and minerals helped bind it into rock. Its layers remained, providing the lines we can follow through cliffs that the sea continues to wear away.

For people building in Caithness, those layers offered a useful starting point, allowing the stone to split into slabs that could be shaped for the job in hand. Walls, floors and roofs all made use of it, while upright flags could form fences without requiring a succession of timber posts and rails. At Camster, the durability of the material and the skill of its builders allow us to enter burial chambers constructed more than 5,000 years ago. Looking at their work after examining a layered cliff, it becomes easier to appreciate how well people understood the stone available to them.

James Traill later developed the resource commercially at Castlehill, sending paving far beyond Caithness, a story we explore in the History and Heritage section of Discover. At our own home, I replaced the austere concrete slabs outside the entrance with beautifully finished local stone, choosing it for its appearance as well as its usefulness. I enjoy returning to that stone after showing guests its natural form beside the coast. In the audio blogcast, we visit Achanarras, where my dad and I searched through broken pieces for fossil fish, and discover how animals that once swam in the lake remained recognisable within its stone.

To learn more, listen to the blogcast or book one of our North Coast Explorer private tours.