Craigahulliar ASSI

The features of geological interest in Craigahulliar are a result of the volcanic activity experienced by this region during the Tertiary period, some 60 million years ago. The site is particularly important for the diversity of basaltic and related rock type and include the lower of the Interbasaltic 'red beds' and the first flows of the Causeway Basalts. The former has associated lignite beds with preserved macrofossils, while the latter occurs in a number of textures representing diverse cooling environments both on land and in or close to water.

A range of unusual minerals are present together with notable lava cooling features such as columnar basalts, chisel marks and blister surfaces.