Scientific and archaeological analysis of the remains discovered by Michael Chambers on Bengorm Mountain two years ago show they were placed there around 1,200 years apart, some as early as 3,600 BC.
Rather than a burial place, osteoarchaeologist Linda Lynch said it was a ritual place where bodies were placed to decompose.
“Only a very small proportion of each skeleton was found, with the majority of bones apparently deliberately removed. The discovery indicates highly complex processing of the dead,” she said.
The bones of at least 10 adults, adolescents, and children were identified from those removed in a rescue excavation directed by Marion Dowd of Institute of Technology Sligo, a leading expert in cave archaeology. She was commissioned to undertake the work by the Department of Culture, Heritage, and the Gaeltacht’s National Monuments service after the bones were determined to be ancient.
Mr Chambers came across them in a cave-like chamber among massive boulders in the north-west Mayo mountain in August 2016. The bones were scattered over the rock floor, prompting the investigation that has led to the details released yesterday by Culture, Heritage, and Gaeltacht minister of state Josepha Madigan.
She thanked the hillwalking community for reporting the find.
“This is a fascinating archaeological discovery. Such vigilance is extremely important to us in helping to protect and understanding our archaeological heritage,” said Ms Madigan.
The excavation and research, commissioned in consultation with the National Museum of Ireland, found that the most recent remains are those of a child who died around 2,400 BC.
It is now believed that the bodies were brought into the cave chamber and laid out in a pit. At some later point, the skulls may have been deliberately broken in a complex burial ritual and the larger bones removed.
“Large pieces of quartz had been placed in and around the bones. When the radiocarbon dates came through it was very exciting,” said Dr Dowd.
“Not only were these bones Neolithic, but the dates showed the site had been used for over 1,000 years.”
Ms Madigan said the glimpses into prehistoric Ireland more than 5,000 years ago show archaeology’s enduring capacity to enthral.
“Such discoveries... demonstrate how advances in scientific research are affording us a better understanding of Ireland’s ancient past and its people,” she said.