How to recognise them

Palm-sized dark circles.

Fossil Info 

These are fossil burrows that are circular in shape in plan view. These burrows were made by extinct crustaceans (similar to horseshoe crabs) that lived close to river channels. The crustaceans made the burrows as they tried to escape from sand laid down during floods – we call these “escape structures” The burrows were later infilled with more (slightly darker) sand, helping us to recognise them in the rocks as we see them today.

Fun Fact

You can find Beaconites in 400-million-year-old Devonian rocks on Slea Head on the Dingle peninsula in Co. Kerry and at Boyces Bay on the Hook Head peninsula in Co. Wexford!