From South Wales Bouldering Guide Wiki
A sandstone natural outcrop overlooking Pontypridd with two free standing boulders. Unfortunately they are only two meters high. Nevertheless they still provide some worthwhile top-outs, traverses and eliminates. The common can get quite busy with locals so be prepared for some sarcastic comments while climbing on the boulders. One such comment, I had while traversing the rocking stone was 'Can't you get on top of that?' and he then suggested an easy way up for me and wait for it. Actually shows me.
Approaching from the North on the A470 take the Pontypridd junction and turn left towards Cilfynydd. At the junction, continue up the hill for about 100m, until a free standing boulder is visible through the trees on the right hand side on the common. Parking is possible on the left hand side.