Cnoc Raithní is a Bronze Age burial mound. It was previously covered by sand (like many thing on Inis Oírr!) but was uncovered by a major storm in 1885. While it may not be the most impressive looking site on the Aran Islands, it is a significant site which probably pre-dates Dún Aoghasa. The site was excavated in 1886 by D.Murphy and important artefacts were found with remains dated at 1500BC.
The site itself consists of a sandy mound 21m in diameter, revetted by a drystone wall. Inside lies a cist, formed by a circle of upright slabs standing 4ft high. On the top, the remains of slab lined graves can be seen, as well as 2 small limestone pillars.
When the cist was excavated, they found pieces of a Cordoned Urn, a smaller vessel and a bronze pin. The urns contained fragments of burnt bones and a charred substance.
This is typical of burials during the bronze age from 1500BC to 500BC. Cremations were common, and the burnt bones were often placed in decorated Urns, of which there were several types – Encrusted, Collared and Cordoned. The Urns were placed upside down in the grave, usually with a smaller food vessel. Sometimes other items such as daggers, pins, beads or battleaxes were placed alongside.
You can find more information about Ireland during the Bronze Age here.