A council's claim that taxpayers could be hit with a £110m bill to safeguard a 4000-year-old group of stones has been labelled "ludicrous and misleading".
Herefordshire Council said £110m was the figure it had been quoted for the cost of building a tunnel underneath the Rotherwas Ribbon.
The feature was unearthed by workmen building a relief road in Hereford.
Campaigner Bob Clay said the figure was "extraordinary" and claimed the council was trying to mislead the public.
The council said the £110m tunnel was one of the options to be discussed next month at a cabinet meeting on how to deal with the Ribbon.
It said other options include abandoning the road at a cost of £6m and building a bridge at a cost of £10m.
Work on the road at the Ribbon site was abandoned in May when the feature was discovered.
Council officers have recommend that work on the road continues at an estimated cost of £400,000, and that a protective shield is built over the Ribbon.
But campaigners want the road to be diverted around the ancient feature, which they say could be as important an archaeological site as Stonehenge.
Mr Clay said to BBC News Online of the £110m figure: "I do find it extraordinary.
"I think it's a case of building up a straw man to knock it down.
"That they've (the council) used the figure this way makes one suspicious of how they're approaching the whole matter.
"I think this is designed to mislead the public."
The council has warned that if any of the measures are adopted other than the one its officers have proposed the county will face "serious financial challenges".
It added that spending money on the Ribbon could cause other important projects to be halted.