The conglomerate visible at the southern tip of Ynys Arw and elsewhere is of great
geological importance. The source of the granitoid boulders is as yet unknown

Another good exposure of the conglomerate

The same conglomerate contains sub-angular pelitic and limestone clasts and even
possible non-igneous clastic dyke features such as the lighter vein at bottom left

The conglomerate at Ynys Arw shows many different aspects

This view shows the rounded aspect of the granitoid clasts and the sub-angular aspect of
some other types of clast