The earth’s changing orbit around the sun created a distinct repeating sequence of climatic change in the area, transitioning gradually from a deep lake environment to dried out desert conditions. This transition was repeated in cycles, with each one lasting 100,000 years and forming approximately 16 meters of rock.
In the last ice age, glaciers travelled across the area and emphasised the stepped profile of these sedimentary layers, wearing away the softer rock. Each step on the hillside you can see represents one ‘cycle’ of the sediments deposited in the lake basin. This can be seen very prominently on the slopes of Kierfea hill and the south-facing slope of Faraclett, which you’ll see if you look north whilst approaching the pier at Egilsay.
