On the Culture 24 web site, sponsored by the Dept of Education, Arts Council England, MLA Museums etc, we find the following nonsense:
"Archaeological investigators from National Museum Wales say "99%" of rhyolite rocks found at Stonehenge can be matched to ones found in a 70-metre stretch of land in North Pembrokeshire."
How wrong can you get? This wasn't a National Museum of Wales investigation -- it was a bit of cooperative work involving Rob Ixer and Richard Bevins. They weren't archaeological investigators - they were (and still are) geologists. They did not say that 99.9% of rhyolites at Stonehenge can be matched to Rhosyfelin. They said that at least 99.9% of the rhyolite DEBITAGE (from those parts of the site from which flakes and fragments have been collected) could be matched to samples collected in the Rhosyfelin area -- and they specifically said that the rhyolite orthostats at stonehenge are NOT from this locality.
This would be funny, if it were not for the fact that this site is heavily used by teachers and students, who presumably accept that what is on the site is authoritative and accurate. Oh dear oh dear.....
Stonehenge rocks pinpointed to Pembrokeshire in National Museum Wales investigation