JUST before he retired as the manager at Castle Cement quarries in Clitheroe, I had several conversations with Keith Hall.

Like most quarrymen he knew the earth and the need to conserve it. Quarries are fine and essential providing that they are landscaped.

Keith realised that, when work has finished, quarries make excellent nature reserves.

This was certainly the case with Salthill, which is a wildlife oasis in the middle of an Industrial estate. I have always loved these places in the summer when the limestone areas are perfect habitat for rare plants, including the bee orchid. The flower bears an uncanny resemblance to the female bumble bee. As the male bee approaches what he thinks to be a mate he pollinates the orchid. Dave Pomfret is not only a quarryman but one of the finest photographers of wildlife and over the years he has taken pictures of many wild flowers, including the bee orchid.

A few days ago Keith told me that old quarries can also be fascinating in winter. Once the vegetation has died down it is easy to look at the exposed limestone and see the fossils of which the rock is composed.

There are several good viewpoints from which it is easy to see that Clitheroe was once a warm shallow sea, full of sea creatures called crinoids or sea lilies. The name lily is confusing because crinoids were not plants but animals and their shells were made of calcium carbonate (limestone). Over millions of years the animals died and their heavy shells fell to the bottom. During a long period of even more global warming than we are seeing now, this sea evaporated and the shells were crushed to produce the limestone which we quarry today.

From the car parking area turn uphill keeping the road on the right. Look for a sign showing that you are on Lincoln Way, which was an area of land owned by the Earl of Lincoln from at least the 14th Century. The path climbs steeply through maturing trees, including rowan, ash and with lot of hawthorn and blackthorn. Pass through the trees to an area of grassland and areas of exposed limestone. Look up to see the whale-shaped bump which is Pendle Hill. Bear left.

Approach seats which provide an excellent viewpoint to see that the area was once a shallow sea and is now just a very fertile-looking valley. Follow the obvious path through trees to the right and old quarry workings to the left. The path descends towards the road.

Cross the road to find a set of steps leading up to yet more old quarry workings. This area has been planted with trees and is ideal for a spot of serious birdwatching.

At the viewpoint look towards Clitheroe Castle, set high on a knoll of limestone and dominating the town itself. The Castle is in the middle of a massive restoration programme, partly funded by a lottery grant. This development means that it is worth visiting Clitheroe several times for a year or so as work will reveal more and more bits of the history of the area. From the viewpoint the route descends through woodland and then levels out to reveal the industrial units to the left and yet more old quarry workings to the right. This is another place to enjoy a fossil hunt, but especially in winter this is also a place to enjoy finding several species of fern. The track then leads back on to the road and the roadside parking area.