Conglomerate, County Antrim

Cushenden Bay (left) is bordered on the north side (foreground of smaller picture) by ancient Precambrian metamorphic rocks. The dark-coloured headland on the south side of the bay is formed from red-coloured conglomerates that were deposited by a river around 400 million years ago.

The larger picture (below) is a close-up of the conglomerate, seen in one of the sea-caves that pierce the headland; the pebbles are well-rounded, suggesting they have been transported some distance.

The caves were formed over 100,000 years ago when sea level was a few metres higher than today, and are above high tide.