I've been walking, talking and taking photographs for about 2hrs at this point. To get to Carreg yr Ogof from Waun Lefrith looks pretty straight forward both on the map and on the ground but unless you're familiar with the area or we've been lucky enough to have a prolonged dry spell, you have to choose your route sensibly to avoid the bogs.  

There is a path visible in clear weather but this takes you towards Garreg Las and away from Carreg yr Ogof. It had been dry for a few weeks yet it was still quite wet in places. This view is looking back towards Waun Lefrith and the Carmarthen Fans. 
I followed the path across the area of shake holes until I met the bridleway between Dan yr Ogof and  Llanddeusant. Then I climbed directly to the now out of sight, Trig Point of Carreg yr Ogof.

You could miss this summit out but I feel like I've cheated myself if I do that. Besides, it commands some lovely views over the lowlands and it's got some shelter for a place to have some grub! Behind, you can make out the distinctive silouhette of the burial mounds of Carnau'r Garreg Las at Grid Ref SN777202. The hill is called Twyn-Swnd and these cairns are technically recognised as round barrows.

Initially I was going to post the photos I took of the burial mounds while stood on top. However, I think that would take away some of their mystery as, until I'd climbed them for myself, I had no idea if they were hollowed out or simply piles of rocks - you'll just have to find out for yourselves too. The one to the right is the Northern one known as number one by the Royal Commission on the Ancient and Historical Monuments of Wales ( RCAHMW ) and predictably the other is number two. More information on these and other cairns can be found on my other blog

In this picture I'm looking back at the cairns (through the increasing rain), along the top of Garreg Las. The walk along the plateau can be time consuming, especially when its wet under foot. The rocks are very slippery and cover the top. I find that its better, for the sake of progress, to walk to the East of its centre as the rocks are smaller but the Western edge is a must see also. The Beacons Way follows this Western edge. 

Eventually you'll come to Godre'r Garreg Las where it's time to pick your way/ scramble down the rocks and walk across to approxmiately Grid Ref SN766187 (dark circle of rocks left of centre). The Beacons Way climbs up and over Foel Fraith at this point but on this occassion I preferred to skirt around the edge of Blaen y Cylchau and on towards Cefn y Truman.
This is looking back at Godre'r Garreg Las, on a sheep track above Blaen y Cylchau which incidentally is designated a nature reserve. The rain was just about clearing up by this point - waterproofs creating more condensation than protecting me from the rain, despite being Goretex.
I said it was a sheep track!! I really felt like an intruder. Cefn y Truman in the background. The walk across is again via a pretty boggy patch but there is a significant path to aim for as you can see to the right of the foremost sheep.
After all the years I've spent walking these hills, I still come across things I've not previously noticed. I now call this rock "Gwely'r Cewri" although it's a bit small for the Black Mountain's real Sleeping Giant.
Coming down from Cefn y Truman now, the weather is really brightening up at last. The highest point on the horizon is the cairn between Moel Gornach and Garreg Lwyd, to the right of the which you can clearly see Herbert's Quarry, my next stopping point, below Foel Fawr. Along the way I met a really nice man from Rhiwfawr who was out running with nothing but a GPS watch and the clothes he was wearing - I thought I was minimalist when it came to carrying kit! He didn't even have a water bottle, considering he was intent on running a 7-8 mile loop he must have camel like genes :-) !
There aren't that many trees on Mynydd Du so I was quite surprised to find this little illegal immigrant nestled away above the Afon Clydach.
Waterfall at Grid Ref SN722189 - very pretty when frozen and can be quite powerful in flood. There is another one a bit further down stream that I keep meaning to photograph but never seem to get round to it.
Leaving behind Herbert's Quarry and for me the Black Mountain proper, just above the A4069. I stopped for the rest of my sandwiches before setting out on the final leg of the day's walk to the west of the road. A little into the unknown for me really as I'd only ever walked bits of it before......