Bones rarely survive more than a few centuries in Guernsey’s acidic soil.
But Dr de Jersey said four groups, which include skull, leg and arm bones, could be around 4,000 to 5,000 years old – the oldest he has ever excavated in Guernsey.
‘It is unusual to find bones this old, but the sand helped preserve them,’ he said.
‘This is a very exciting find, due to the rarity of prehistoric bones.’
Radiocarbon dating is due to take place shortly, with the results expected back in the summer.
The bones were spotted protruding from an earth bank at Jaonneuse Bay by a walker just after lockdown, who called in the police. But it was soon apparent that the States’ archaeology department was needed.
They began carefully excavating the earth bank and found bones in four groups.
‘I think they will turn out to be from four different individuals, but we can’t say for sure yet,’ he said.
‘We have cleaned up two sets and two still need to be cleaned. Of the two sets we have cleaned, they are definitely from two different individuals, as there is repetition. We also expect to find they are different ages.’
It is believed one is an older individual, based on the bad arthritis at the base of the skull, while the other is believed to be a young adult, based on the wear on the teeth, which are in quite good condition.
However only part of skeletons – most notably the skulls, with a few extra bones – have been found.
Dr de Jersey said the bones were likely not laid to rest originally in this spot. In fact they may come from a dolmen – which were in use around this period – and could have been moved. There has been evidence before of bones being moved around and out of dolmens or being burnt.
He said the bones were moved in prehistory, but did not know why some bones were selected.
‘For whatever reason they were reburied, they have been done very carefully,’ Dr de Jersey said.
‘They were buried in sand, so if it was not done carefully, then they would have scattered. They chose mostly pieces of skulls.’
The nearest dolmen is La Varde, on the common, but that is still quite a distance away. Dr de Jersey said it was possible there was another dolmen on the headland which has been lost or washed away.
Prehistoric bones have been found in La Varde and Dehus dolmens, but these were excavated by enthusiastic amateurs in the 1800s and were not recorded in the way specialists would today.
Dr de Jersey said that made the latest find quite exciting.
He added that it was possible that DNA could be extracted from the bones, so they could see if the four individuals were related.
Some prehistoric flint and pottery were also found.
‘There is a lot we might never know, particularly why this was done and what the selection process was for the bones,’ said Dr de Jersey.
‘The pottery is low quality.
‘It could be a cooking pot or a cremation pot. We just don’t know.’
Sea levels would have been one or two metres lower at the time of the burial, but the area would still have been coastal when the bones were buried.