Recent excavation finds evidence of a settlement thought to date back 6,500 years.
Archaeologists from the UK and France were in Herm in September '25 to further examine its megalithic past.
A team supported by the French Ministry of Europe and Foreign Affairs has been studying two sites on the Common.
One, the tombstone at Robert's Cross, has been extensively excavated over the years, but the team were again impressed by the sheer size of the rocks used to create the burial chamber.
Samples have been sent for analysis to find out when the tomb, which is around 6 thousand years old, collapsed.
Nearby, an area by the path to Bear's Beach has been dug up, which suggests farming was active on the Common 6,500 years ago.
The experts say post holes for Neolithic houses suggest a population that pre-dated the tomb building period.
More excavations are planned for next year.
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