Visited 21.2.2009, approaching along the beck from the south (along the "Meanwood Valley Trail" footpath). Plenty of snowdrops and crocuses in evidence, making for a lovely spring day. The stone is an attractive pointed piece of granite, five feet or so tall. It is a striking bright green colour, from the moss and lichen covering it. Being granite, it would take a lot to wear it down and there are certainly marks which could be water erosion lines.
However, it is quite "sharp" along the edges, which may indicate a younger age. I have been looking at the available editions of the largest scale OS maps (County Series 25 inch to the mile) from the 1880s onwards, up to the latest 1:1250 scale OS maps. The stone is not marked on any of them, which is odd if it has always been there - having said that, it's odd that's it's not shown on the OS even now, as it is certainly substantial enough to merit a "stone". My visit also took me to the Uni campus at Beckett Park, where estate maps of the area from the earlier 18th century are on display - until the early 18th century this whole area was owned as part of the landholdings of nearby Kirkstall Abbey, so it would be interesting to know what the Cistercian monks would have made of a prehistoric pagan monument being on their land, if it was there then.
Worth a visit, Meanwoodside is easily accessible and has a car parking area.
The local historian Arthur Hopwood told me about this stone.
It's his opinion that this is one of the many stones erected around the beckside by Edward Oates, who bought this land in 1834.
Mr. Oates put up the large stones around the pond just north of this, and also installed the 'clapper' bridges found there. It seems he had a thing about having 'ye olde looking stones' on his estate.
Edward Oates was a member of the Mill Hill Chapel, in Leeds City Centre, and apparently brought some of the stone from there, including the two rough stone 'pillars' that are to be found near the pond, a little further up the beck from here.