A dig has begun to explore a hidden complex of passageways found during building work at the Auchrannie Hotel and Spa, Arran.
Previous excavations at the site in 2001 revealed the remains of two ancient roundhouses that would have been used by early settlers on the islands.
Now experts have returned to the site to explore a series of underground chambers beneath the structures, which may have lain undisturbed for more than 2000 years.
Among the relics revealed by the first dig were two coal bracelets, thought to have been made by the inhabitants, and a bronze spiral finger ring.
An open space underground, known as a "souterrain", was also identified, and the team plans to carefully excavate it in the coming weeks ahead of fresh building work at the hotel.
The Auchrannie souterrain was not disturbed during the 2001 excavation and remains underground. From evidence gathered at the surface, it has been established it is made of two curved underground passages with two connected stone-lined cells.
These could have been used for storage of craft goods and food or as hiding places during times of strife on the island. Previous examples of souterrain found in Scotland are thought to have been used to possibly house animals.
The excavation is being undertaken by Ayrshire-based Rathmell Archaeology Ltd, and archaeologist Claire Williamson said it could shed a light on the lives of islanders in the dim and distant past.
It is believed the roundhouses could reveal the remains of a settlement from the late 2nd or early 1st century BC, which was built at the mouth of Glen Cloy on prime agricultural land.
Ms Williamson said: "There is the potential for the souterrain to hold a treasure trove of artefacts from the Iron Age.
"Should this be the case we may gain an unparalleled insight into lives of the inhabitants of Glen Cloy from this distant time."
Auchrannie was acquired by the Johnston Family in 1988 to provide indoor leisure facilities on the island, and has grown from a 16-bedroom guest house to a resort comprising two 4-star hotels.
Gordon Hay, the hotel's business development manager, said: "The whole team at Auchrannie are really excited to learn of this discovery; obviously we are all hoping the archaeologists uncover some items of significant interest during the dig and we will be keeping a close eye on developments as they happen."
"The dig is being undertaken as a result us looking to develop a new style of accommodation on the resort over the winter, so if it had not been for our development plans these historic findings may have lain undiscovered for many more years."