Grey Bools, Wick
Significance: this site provided one of the first records of cliff-top storm deposits In Scotland.
Grey Bools, Wick
Significance: this site provided one of
the first records of cliff-top storm
deposits In Scotland.

Grey Bools, Wick

Significance: this site provided one of the first records of cliff-top storm deposits In Scotland.

Beside the car park at the end of the minor road along the cliff tops south of Wick is a remarkable accumulation of large flagstone boulders. First described by Hugh Miller, the boulders are less extensive than formerly, many having been cleared from the field east of the road.

The boulders lie between ~12 and 17 m above sea level at head of a ~150 m long stepped rock ramp that slopes to the north. The largest boulder, Charlie’s Stone, has a volume of 110 m3 and weighs around 500 tonnes. Many boulders are longer than 1 m. The boulders are stacked towards the north and northeast and the strength of this imbrication leaves little doubt that the blocks were deposited by storm waves from this sector. The blocks have been torn from a rock step at around 5 m asl on the ramp.

Although there are some small boulders and sockets that appear relatively fresh it is clear that these cliff-top storm deposits have not been mobilised over the past century.

  • the boulders are covered with lichen
  • there is no modern flotsam trapped under the blocks, unlike at Shetland sites
  • the Grey Bools were described in the 1840s and again in 1864 and so must predate the demolition of the breakwater in storms of the 1870s.
  • a boulder accumulation is shown on the Admiralty Chart of Wick Harbour, published in 1857

Bruce Woodman-Smith (2004) has compared the edge rounding of the boulders with that in local kirkyards. He estimates that the boulders were emplaced between 1800 and 1850 and notes that the most extreme storm in this part of the North Sea occurred in January 1830. With recent records from oil rigs of rogue waves up to 26 m high in the North Sea, it is clear that northerly storms have the potential to generate very large waves that may have major impacts on cliffs in Caithness.

Panoramic view over the Pentland Firth in Caithness, to the Orkney island of Hoy (AdobeStock _#322076170)