Yesnaby, Orkney Mainland
Significance: a coastline noted for its Devonian geology and coastal geomorphology

Cliff-top scour zone

Few localities combine the wealth of geological interest with the stunning setting of Yesnaby. As the swell crashes in from the Atlantic, the cliffs resonate with the blows and the compression of air in hidden caves bubbles air through ponds high on the cliff top. The modern pulse of erosion has exposed a far older history, for here is laid out the desert of the Devonian.

To the south lies the granite basement, with the original scree still plastered on the sides of ancient hills. The sub-Devonian surface is buried by many hundreds of metres of flagstones that accumulated in Lake Orcadie. The sandstones show many signs of a desert origin, with dune bedding, sun cracks and the formation of gypsum crystals. The sands were transported in large rivers and the channels can still be seen. Signs of life are everywhere, from tracks to burrows and fish and hardened hydrocarbons. The horse-tooth stromalites are easily found, close cousins of the few surviving colonies on Earth.


The cliff feels the full force of Atlantic storms when spray jets high into the air. Waves arrive here unchanged from the deep ocean and during storms the cliff top is washed, shifting blocks landwards and scouring away the soil. All the classic landforms of coastal erosion are revealed on a walk on the cliff tops – cavesarches and stacks.

Cliff profile and storm deposits

Beyond you America
behind you Stromness
far from me now
the tides changing on you
as I walk the crowded mile
of Byres Road, you curve
in my mind like a film
I would run over your top lip
through an equinoxial autumn
putting words in the mouths
of fishermen & crofters
you speak to me still
a language of salt & gull & wave
Hoy over my shoulders like an uncle

Yesnaby by George Gunn

Key Geomorphological Sites

  • Significance: a coastline noted for its Devonian geology and coastal geomorphology

  • Significance: this bay lies adjacent to Skara Brae and provides evidence of the interaction between coastal processes and human disturbance between 6600 and 4400 radiocarbon years ago. The settlement first re-emerged from the dunes after a storm in 1850.

  • Significance: this site provides evidence for changing ice-flow conditions during the last ice sheet glaciation

  • Significance: the construction of the Churchill Barriers started in 1940 and led to a fundamental change in the pattern of tidal flow around Scapa Flow. A range of coastal landforms have been created subsequently which illustrate the fundamental control of coastal configuration on the transport and deposition of sand.

  • Significance: Rackwick lies at the southern end of two major glacial breaches on Hoy. Its well-developed moraines indicate that at the close of the last glaciation two lobes of ice retreated northwards at a time when the Pentland Firth was probably still occupied by ice.

  • Significance: The Old Man is the tallest sea stack in Britain, 137 m high

  • Significance: a superb corrie formed at an unusually low elevation that was last occupied by a small glacier only 11,000 years ago

  • Significance: Ward Hill provides examples of a range of active and fossil periglacial landforms. As the highest point on Orkney it also provides evidence of the thickness of the last ice sheet

  • Significance: the site of a former small corrie glacier on Hoy

  • Significance: the site of a small corrie glacier during the Loch Lomond Stadial

  • Significance: a raised beach deposit at 6-12 m asl buried by till

  • Significance: a possible Scandinavian erratic on Orkney.

  • Significance: a peat deposit with willow boles formed 6500 years ago and now lying below sea level

  • Significance: the Kilns of Brin-Novan is an excellent example of an interconnected series of caves, arches and blow-holes which illustrate the sequential development of these features.

  • Significance: this coastal section provides perhaps the best available exposure of the shelly till which is characteristic of the eastern part of Orkney

  • Significance: exceptional cliff scenery and dramatic cliff-top storm deposits