This open cavern 150 metres inland is part of a collapsed sea cave into which Atlantic waves find access through a fracture in the volcanic rocks.
The Hols o' Scraada is a partially collapsed sea cave. Waves roll down a subterranean passage to break on the beach 150 metres inland. Originally, the inlet was two holes with a land bridge between. The natural arch between the hols collapsed on 9th October 1873 shortly after Morgan Thomason crossed over it on horseback.
Dr Samuel Hibbert (1782-1848) described "a large cavernous aperture, 90 feet wide, which shows the commencement of two contiguous immense perforations, named the holes of Scranda [or Scraada], … where in one of them that runs 250 feet into the land the sea flows to the utmost extremity. Each has an opening at a distance from the ocean by which the light of the sun is partially admitted".
The sea cave is carved out of the volcanic rock andesite which erupted from the now-extinct Eshaness volcano 395 million years ago. Lava shrinks as it cools, often forming columnar joints and cracks in the thicker flows, which have been exploited by the sea over thousands of years.
Just east of the Hols o Scraada you see the remains of a Norse mill. The traveller Rev. George Low wrote about Shetland’s Norse mills in 1774.
