Where is the Carn Goedog spotted dolerite?

This is one of my better images of spotted dolerite from Carn Meini or one of the other eastern tors.  At least, that's where I think it came from -- it's actually the surface of a dressed stone (hence the fresh appearance) in the front wall of the nonconformist chapel in Mynachlog-ddu.  Many of these stones were taken down from the mountain and dressed for the front (posh) face of the chapel.  Whether they were quarried is another matter -- perhaps "collected" would be the best word.

Click to enlarge.  The texture of the stone shows up rather well.

Just a reminder -- if the idea of proto-Stonehenge is to have any credibility at all, stones with a surface like this will have to be found in abundance by MPP and his fellow workers during their current dig at Waun Mawn.  (It is a central part of their thesis that scores of monoliths were carried from the supposed Carn Goedog "Neolithic quarry" and were parked up in a giant Waun Mawn stone circle prior to being transported to Stonehenge.)  When I looked quite intensively at the dig site, I did not find a single piece of spotted dolerite..........