1-649-587 - Historica Graphica Collection/Heritage Images

'Near view of one of the Shiant Isles', Outer Hebrides, Scotland, 1829. The islands are notable for their geology, with cliffs consisting of great columns of dolerite, formed when volcanic lava seeped into layers of sedimentary rock and cooled. The softer sedimentary rock was later eroded away, leaving the columns of dolerite behind. The same processes formed the similar structures on the island of Staffa and at the Giant's Causeway in Northern Ireland. From A Voyage Around Great Britain Undertaken between the Years 1814 and 1825 by William Daniell.