The Bwlch Ungwr Quarry

 

Meta-mudstone or slate outcropping in the small quarry; this is the resource that was exploited (Courtesy Hugh Thomas, Preseli 360)

Thanks to Hugh for posting this and the images below on his Facebook page -- the images show a small quarry that I have walked past scores of times without noticing.  Grid ref SN138329.  It's rather convincing, and is quite unlike the imaginary Neolithic quarries of Carn Goedog and Craig Rhosyfelin that are much loved by MPP and his digging team. The excavation pits are quite clear, and I suspect that this might have been a short-lived trial dug by some people looking for slate, or else a site exploited by a local farmer or group who were simply looking for roofing or building materials.  Rough flat slabs like these were widely used for stone walls and for building dwellings and farm buildings. 

So I think this is probably related in age and origins  to the string of quarries near Waun Mawn, on the hillside below Cnwc yr Hydd.  I suspect this is not prehistoric, but from historic time -- maybe from the 1700s or 1800s.  Transport from here was mostly downhill, and quite easy for wheeled vehicles, along the route of the Golden Road.

I am still convinced that the only prehistoric quarry in Preseli is the one at Foel Drygarn, which is probably from the Bronze Age and the Iron Age.

More of Hugh's excellent images:

https://brian-mountainman.blogspot.com/2018/09/the-cnwc-yr-hydd-quarries-opinion.html

https://brian-mountainman.blogspot.com/2023/03/the-foel-drygarn-quarries-what-is.html