The island was excavated from 1955 to 1956 by archaeologist, Michael J. O'Kelly. He suggested that there were two different phases of occupation on the island. The first phase was from the sixth to the seventh centuries.[4] The earliest buildings were two wooden structures––a circular hut and another rectangular building. The rectangular building, found in the center of the island, was believed to be an oratory. The hut contained animal bones, charcoal and shell. Middens uncovered on the island revealed that the monks had a diet that included shellfish, cod, ballan wrasse, seal, fowl, and meat brought over from the mainland.[4]
There was a second occupation on the island shortly after the first phase, probably during the 10th or 11th centuries. A burial ground with more than thirty graves was uncovered during excavation. Some burials were likely to be monks who had died on the island.[5] In the second phase of occupation, a stone circular building, the clochan, and a stone oratory replaced the wooden structures. The stone oratory probably was built at a later date than the clochan and is made of Valentia slate.[6] At least eight of the burials date to the later period of occupation. Also uncovered during excavation were two stone crosses, several cross slabs, one with an ogham inscription.[5]
During a later excavation, in 2004, two shrines were discovered in the south part of the island. The first shrine measures 26 m (85 ft) and its surface is paved with Valentia slate and white quartz pebbles. It is thought to be a gable-shrine. The partial remains of four individuals were uncovered during excavation. The second shrine is trapezoid in shape and may have held human remains in the past.[5]
