A new discovery on an island off north Lewis could change the understanding of the history of the area.
The kiln on Dun Eistean was used for drying out grain
Archaeologists have found a kiln inside a building which has been excavated on Dun Eistean, a stack which lies near the Butt of Lewis light-house.
Kilns were used to dry out grain, which could then be used in the preparation of food or alcohol.
Dig supervisor Dr Rachael Barrowman said it indicated that there was a more permanent settlement than thought.
Previously, it had been believed Dun Eistean had only seen short bursts of defensive use down through the centuries.
Dr Barrowman said archaeologists had no idea the structure was a kiln until the classic structures started to emerge from the acidic peaty soil - the flue, platform and bowl-like area over which the grain was dried.
She said: "We'll now focus on the bottom of the kiln. We might find grain or carbonised wood."
The lottery-funded dig began in 2005 and comes to an end in early August this year.
It followed extensive archaeological surveys of the Ness area and the island itself.
The dig has been supported by the National Lottery and other bodies including the local council and the Clan Morrison Society.
The excavation has been undertaken by the Glasgow University Archaeological Research Division, who have liaised closely with the Ness Historical Society. Seven structures have been investigated.
The kiln, with its bevelled stone bowl into which hot air from a fire was channelled through a stone flue, has been revealed in a large four-roomed building near the footbridge which connects the stack with mainland Lewis.
Until the footbridge was built in July 2002, access was by climbing down and then up sharp cliffs at low tide.
The Lewis historian and expert on indigenous architecture, Dr Finlay Macleod, said he was excited by the find.
He said: "This kiln is so strangely identical to the ones people saw used in the villages of Ness until after World War Two - the platform, fire area, the whole thing.
"A kiln implies that there was quite a bit of grain dried here, to make meal, or beer or whisky."
The dig at Dun Eistean is scheduled to end in August
Dr Macleod said many questions have still to be answered as a result of the find.
There is no running water on the stack, which would be needed for whisky production, although there is a good supply on the coast of Lewis.
Dun Eistean was the traditional strong hold of Clan Morrison.
It was thought the island was heavily used in the 16th and 18th centuries.
Musket balls and pottery are among the artefacts discovered so far.
A square tower made of stone and cemented with clay has also been excavated this year.
Large hearth areas have been discovered this year. The island had extensive views of important trade routes through the Minch.