Yesnaby Sandstone Group

Yesnaby Sandstone Group Stratigraphic range: Givetian (Devonian)
Dune cross-bedded aeolian Yesnaby Sandstone exposed in the cliffs at Yesnaby and on Yesnaby Castle sea stack
Type	Group
Unit of	Old Red Sandstone Supergroup
Sub-units	Qui Ayre Sandstone Formation, Harra Ebb Sandstone Formation
Underlies	Caithness Flagstone Group
Overlies	unconformable on 'basement'
Lithology
Primary	sandstone
Other	siltstone, conglomerate
Location
Region	Orkney
Country	Scotland
Extent	west coast of Mainland, Orkney
Type section
Named for	Yesnaby

The Yesnaby Sandstone Group is a Devonian lithostratigraphic group (a sequence of rock strata) in west Mainland Orkney, Scotland. The name is derived from the locality of Yesnaby where the strata are exposed in coastal cliffs.

These strata are only exposed on either side of the Garthna Geo Fault in the Yesnaby area of west Mainland, Orkney.

The Group comprises the Qui Ayre Sandstone Formation and the Harra Ebb Sandstone Formation. The basal beds are talus and alluvial fan facies deposited in a fluvial or lake marginal environment probably during the Emsian Stage of the Devonian Period.