Advice to walkers heading this way. If you plan to walk up the valley of the Afon Disgynfa above the impressive Pistyll Rhaeadr, don't do so in high summer when the ferns are at their most luxuriant. The whole valley is choked with them them and my trousers were soon drenched through from lurching through them. After you pass the river coming down from Cym Rhiwiau the path, such as it is, peters out. The Nuttalls recommend sticking with the valley for another kilometer or so but I didn't fancy fighting my way through those giant ferns without a path. So my thought turned to a wall that heads left towards the plateau around here which I though might be a handy navigation aid in filthy visibility. Up I went, steeply at first, heading for the place it turns left again. A little before thus, the 1.25,0000 map has something labelled "pit (dis)". Pit there certainly was a huge hole in the ground the size of a supermarket. I walked gingerly round there of it, hoping there wee no aliens around.
At the wall turning, the navigation gets serious in these conditions and for a big I had to pay attention. Halfway from her to the top though, the weather began to clear beautifully and all I gad to do was point myself at the now obvious cairn (which is in some disrepair and threatening to topple over soon). From here I headed SE, past some woods, over a little hill marked by the OS with a 596 spot height then SW along a fence to a point where a shiny yellow sign told me sternly not to be a motorbike. At this point, though the ground was not remotely difficult, I carelessly went over on my ankle. It hurt like crazy for a minute but then didn't trouble me much walking back, down a path then along a track back to the car park at the waterfall. But it was one of those injuries that creep up on you and a couple of hours later I could no longer walk at all.