IT's literally a case of turning a mountain into a molehill.

An entire hill, famed for its archeological heritage and geological significance, is to be removed from the Scottish skyline to make way for a quarry under plans being considered by West Dunbartonshire Council.

Sheep Hill, in the Kilpatrick Hills on the Clyde, is the site of ancient Bronze and Iron Age forts which local residents and experts say will be destroyed by the expansion of a stone quarry.

The hill also features in a painting by the 19th-century Scottish artist John Knox, and is used by geology teachers to show how the landscape has been shaped by volcanoes and ice ages.

Allowing the hill to be wiped off the map would be "an act of wanton destruction of our environment and inheritance", according to Clydebelt, a local environmental group, which is calling for Scottish ministers to intervene to save the hill.

"Sheep Hill is liable to be destroyed," said the group's secretary, Sam Gibson. "This would leave a gaping hole in the side of the hill showing the workings of the quarry and fully visible from a distance."

A proposal to revise mineral permission for an existing quarry run by a local firm near Sheep Hill is due to be discussed by West Dunbartonshire Council on Wednesday and has provoked fierce opposition from local groups.

They say that, as well as damaging important archaeological remains and ruining the landscape, expanding the quarry would threaten wildlife and trees. The North Bank Environmental Group has filed a formal complaint to the ombudsman about the council's handling of the development.

"The planning authority has kept the local community in the dark about this potential environmental vandalism for very nearly 10 years," alleged the group's Derek Fabian.

Silverton and Overtoun community council says digging away the hill would be irrevocable. "When Sheep Hill is gone, it is gone," said the council's Rose Harvie. "Future generations will look back and wonder how such destruction could have been permitted."

Archaeologist Dr Euan MacKie has studied Sheep Hill since the 1960s. "It would be an act of appalling vandalism to destroy it," he said. He accused the quarry company of having little concern for the area's rich archaeological heritage, and the local authority of failing to capitalise on it.

Scottish Natural Heritage has previously expressed concern that quarrying would damage the landscape. But, according to one official, it won't say anything now because its "level of involvement in planning cases has become more restricted".

The quarry company, William Thompson & Son, which has extracted whinstone at its Sheep Hill quarry for decades did not respond to repeated requests to comment last week.

Director Andrew Thompson was quoted in a local newspaper saying a "hornets' nest" had been stirred up by the revision of minerals permission. "I understand fully people's objections to this, but it's not like we would be immediately drilling into the hill the next day," he said.

"If someone can find another site where the minerals are as suitable for quarrying, we will move there. At the end of the day, I'm damned if I do and damned if I don't. If I don't use the land, my company has nowhere to quarry, and if I do quarry the land, I'm the bad guy."

West Dunbartonshire Council pointed out that permission for quarrying at Sheep Hill was originally granted in 1949, and would not be revisited. The revision under discussion this week is to bring the planning conditions in line with current best practice.

A council spokesman added: "Sheep Hill is the site of a scheduled ancient monument. Scheduled ancient monument consent for the removal of Sheep Hill fort was granted in 2002."