To be more explicit as to directions: As can be seen from the OS map, fom the car park at the Cow and Calf Rocks, follow the road uphill and strike off right at a signpost just before the Cow and Calf, which directs you onto the steeper slope. This will take you to the first level, to the right of the Pancake Stone, which you may wish to visit. The moor proper is at the second level, which can be seen straight ahead. The path is marked by a thick post visible on the skyline, more or less behind the Pancake Stone. Once there, just follow the well-defined track, which bears slightly to the left, and you’ll soon see ‘The Shed’ off to your left, after a small lake. You may wish to visit the Grubstones, and then carry on as in the instructions in the entry below this.
To try to pin down the location: You’ll see the ‘Thos. Pulleyn’ stone from the path, but carry on until you reach the stile a short way further on, which you have to climb over. From the top of the stile, if you look southeast (halfway to your right) the circle is about 50m distant, just where the land drops away. You can't actually see it because of the dip. Alternatively, walk about 40 paces southwards along the fence line, and go about 40 paces at a right angle from there. So, I figure the circle has to be about 100m SSE of the 'Thos. Pulleyn' stone.
The circle may best be appreciated with Arthur Raistrick’s survey at hand. I don’t know if there’s been interference, but the central setting is not now as he depicts. It’s a complete near-true circle of 20 stones with a loose stone inside. What’s more, it’s not offset as far southwards as he shows it - it’s almost central. The stones of the outer ellipse are still recognisable from his survey, though some of the smaller stones, particularly at north and south, appear to have been moved. A few are larger than he shows. It may look ragged, but this is a fascinating circle, or enclosure, or whatever it is.
As an aside, if you approach the ring from the Cow and Calf via the Grubstones then instead of walking back the same way you can go on to the Twelve Apostles. Just continue south on the path a few hundred metres to the Horncliffe Well (following the fence, and over a stream) where there’s a stone wall with a stile, and a path on the other side. Turn right (NNW) and you’ll eventually re-negotiate the wall, and almost bump into the circle at the top of the long, long, rise - soon after a modern milestone at a track joining from the left. Be aware that the track can get boggy after rain. As a closing note, from the Apostles continue northwards and take the stone-flagged path on the right, downhill at the fork / junction, then go right at Gill Head (where the path drops sharply) to follow the stream back to the rear of the Cow and Calf Rocks, where you cross it. The entire trip should pass away a good few hours!
The circle can also be approached from the south (shorter), via the Horncliffe Well.
Horncliffe circle is a strange beast and a real bugger to find. In late September 2002 it was badly overgrown with bracken and frequented only by sheep and looked like nobody had been there for a long time. It was so overgrown that I had to walk around it for several minutes trying to figure out if the jumble of rocks was indeed the circle of stones I had seen in a picture (see link). It is hard to work out exactly what the outer ring of stones and the central square stone setting were, many stones are set side by side, in other places stones are missing. It could be that outer stones were the kerb for a central cairn, although I read somewhere that the whole thing may be some kind of iron age settlement building.
Directions to the circle are similar to the Grubstones – set off southwards from the Cow and Calf car-park until you see a hut in the distance. Head towards this, but veer off to the rock outcrop about 20-30 metres to the north. From here a decent track leads south past several grouse-shooting outposts to the right with a fence to your left. After about 20 minutes you will see a dip in the track and a stream a short distance ahead of you. To your left will be an old stone by the fence with the name Thos. Pulleyn engraved on it. From this point you should see a patch of bracken about 30 metres beyond the fence – the stones are hidden deep in this bracken. Walking time from the Cow and Calf if about an hour by the most direct tracks.
GPS Reading SE1333943532
This ring of stones is said to be the haunt of willow the wisps and scary black dogs, according to Paul Bennett in his 'Circles and Standing Stones of West Yorkshire'. In his 'Megalithic Faults of Rombalds Moor and District' article in Earth 14 he even includes fairies in this menagerie.