WILD boar tusks, pottery, spoons, musket balls, keys, pins, millstones, shoe soles, clay pipes. A little treasure trove of artefacts is now on display at the visitor centre in Dalby Forest after they were unearthed at a forest site near Yearsley, south of Ampleforth.

But the small finds were a sideshow to the main discovery - that the site was once a 12th century watermill, almost unique to the area, which operated for several hundred years before being demolished in the 18th century.

Now, after a seven-year volunteer-led project to uncover the watermill, many of its secrets are being shared.

It started in 2011.

Historic records at North Yorkshire County Council indicated that on Yearsley Moor there were heavily overgrown stone foundations of a building described as “medieval or later”.

As part of the Lottery-funded project Lime and Ice, the Yearsley Moor Archaeological Project brought together a group of volunteers to start excavating this building.

Each day they would walk past other, more visible, foundations to get to site. There was limited historic information available, and nothing to be found on old maps.

In 2012 the group started to look at those other foundations they had passed daily and, during initial investigations, they uncovered the edge of a millstone.

Slowly, a more complete picture came into focus. A millpond was discovered. Then, after excavations started, the volunteers uncovered the full extent of the millstone, the walls of the wheel pit, and the cog pit.

“Finding the edge of the millstone was the eureka moment,” said Geoff Snowdon, one of the lead volunteers behind the project. “Because we didn’t really know what we had down there. So that was a revelation.”

In 2014, following the end of the Lime and Ice project and with £1,000 from the Helmsley Archaeological Society, the volunteers formed the Yearsley Mill Research Project and from 2014 to 2017 excavation of the site continued.

The next area to be worked uncovered a flagstone floor, a hearth, a kiln, and the tail race, where the water returned to the stream after turning the wheel.

Excavation then moved to other areas and the volunteers started to uncover pieces of preserved wood - part of the cog wheel, which turned the millstones, and a section of the last waterwheel.

The wheel revealed that it was “overshot” – that is, the water to turn the mill was fed over the top of the wheel. The mill would have been used to grind corn.

The 16th century design of the wheel is, the group say, very rare; only five others are known in the country and these are all in the south of England.

Elizabeth Saunders, one of the other key drivers behind the project, said: “People had said it couldn’t be a watermill. We couldn’t believe it - there was no documentary evidence, it wasn’t on any maps. It had fallen through the cracks.

“There’s a forest there now. People have been walking their dogs past it. And nobody’s known there’s been all this underneath.”

About 6,000 shards of pottery were found - the earliest dates from the 12th and 13th century, with the main bulk of it from the 16th to 18th century.

The water wheel itself and other wooden finds were removed for preservation.

The finds and exhibition were unveiled at a ceremony at the Forestry Commission visitor centre at Low Dalby last Wednesday, where a final unexpected find was revealed.

Research into the mill site established a timeline, from when it was built (probably by Thomas de Colville, the local Yearsley landholder) in the 12th century to when it was demolished by Charles Gregory Fairfax, 9th Viscount, in the 1720s.

This research found that one of the last known millers at the site was George Yoward, who married a Margaret Walls in 1669, and who died in 1724.

After some more research, Mr Yoward’s living relatives were found. One is Tony Yoward, who with his wife Mary had long been something of an expert... on watermills. He even lived in a converted mill in the 1970s.

Indeed, Tony’s son Nick said his parents’ work formed a large contribution to the National Mills Archive in Reading.

But he didn’t know about George. Tony and Nick, who live near Portsmouth, were at the opening. Tony said: “I had a miller in the family and I didn’t know that. I was delighted.”