• The Triassic rocks of Arran, consist of sediments laid down in marine and lacustrine scenarios (Auchenhew Beds), siltstones (Dereneneach Formation) and black mudstones (Westbury Formation). They were laid down when the Arran land mass was probably at a latitude of 32^oN.  The Auchenhew Beds can be seen in outcrop in many places on the south of the Island.

Image 1.  Auchenhew beds outcropping at Levencorroch, the rocks are fine grained, clay rich, parallel bedded and lacking marine fossils.

These rocks were thought to have been laid down in a lacustrine environment.

Image 2.  Fine grained parallel bedded lacustrine Auchenhew Beds, exposed in the burn at Levencorroch. 

Image 3.  Lacustrine Auchenhew Beds, exposed in the burn at Levencorroch. Desiccation cracks, suggest that the lakes in which they

were deposited were impersistent (i.e. dried up).