Mullaghmore Head, Co. Sligo
                                                                                                                                                                           

Mullaghmore Head in County Sligo is the type locality for the Mullaghmore Sandstone, a Formation of Lower Carboniferous age.

The most informative exposures are on the west side of the head, northwards from where the road meets the cliff edge.

The west coast of Mullaghmore Head shows a marvellous range of geological features:
• rocks which were once sediments deposited on ancient river deltas and on the bottom of the adjacent coastal sea;
• the burrowing and crawling traces of organisms which lived in or on the sediment before it was transformed to rock;
• structures preserved in the rocks whose modern counterparts in sand and silt allow us to decipher the conditions in which the rocks were once laid down, some 300 million years ago.



Delta sands

The cliff face in this picture is about 8m (25') high. It shows many layers (beds) of sandstone sloping (dipping) away to the left.

The two thick beds at the top of the cliff are formed of sandstone laid down on the bottom of a river flowing across a delta, the river channel cutting down into earlier deposited sands and silts which form the lower part of the cliff.
The grassy slopes cover much more recent deposits, silt and clay with rounded pebbles and boulders of sandstone, laid down under the ice sheets which covered Ireland during the last ice age