Been over to the Sleek Stone at Broad Haven again today, hunting for more bits of that "super-erratic" which has come -- probably -- from Ramsey Island. In addition to the two large chunks which I think have come from a single "super-erratic" weighing over 100 tonnes, I'm now pretty sure that there is a third chunk of the greenish volcanic rock about 10 m away, at a slightly lower level. I calculate that this chunk weighs about 12 tonnes -- it's smaller than the other two. There's a fourth boulder as well in the vicinity, about half that size and weighing maybe 5 tonnes.
About 50m towards the north there is a second very large erratic now broken into three chunks, one weighing about 17 tonnes, another about 23 tonnes, and another abouy 10 tonnes -- a total weight of about 50 tonnes. Again the rock type is a bluish-green "quartz porphyry" presumably from Ramsey Island.