From 'WRAO' on Facebook:
"Six? possible cup-marks on a stone re-used as a gate post. The hole in the centre is for a gate bolt and is distinctly different in character to the standard bowl profile of the cup-marks... continues...
First Tara.. and now the welsh assembley has followed suit by sneaking through the distruction of one of the most sacred sites on anglesey.
2km from Holyhead is Ty Mawr and Trefignath and surrounding tombs and circles.
Excavators are currently ploughing up the area so as to build a buisness park on the site... continues...
About a quarter of mile further on [from Trefignath ], near Trearddur farm, close to the road on the road on the right, there are the traces of a similar cromlech (now nearly obliterated), called Coetan Arthur. Near this spot, in 1837, a vessel containing a great many Roman copper coins was found, of the later emperors. I took them to the British Museum, but there was none peculiar; and I regret that they were purloined in transmission by post to the owner.
Coflein describes this site as having two stones, one upright and one recumbent, on a rocky rise. The official opinion is now that it could be a natural outcropping rather than a cromlech with the remains of a covering cairn. But they do say that "it is possible that the erect stone was raised deliberately, and it may be a prehistoric ritual or ceremonial monument." The upright stone is 1.6m high, 2.1m wide and 0.3m thick at its base. The prostrate stone at its foot is 2.3m long, 1.5m wide and 1m thick.
The cromlech, or rather cistvaen, of Trefigneth stands upon a rocky knoll close to the farmhouse of Trefigneth, about a mile and a half from Holyhead. There is a commanding view from it over the port and bay of Holyhead, with the Skerries island and lighthouse, and the opposite coast of Anglesey, in the distance.
About seventy or eighty years ago many of the stones, which formed the covered chamber, were wantonly taken for gate-posts and lintels; but the late Lady Stanley of Penrhos preserved it from further destruction at that time, and it remains now as it then was.
It presents the appearance of having been a covered chamber, of about 20 feet in length, 4 feet in height inside, and 4 feet wide, composed of a row of upright stones on each side, covered with large flat stones. There is a tradition that, when first exposed, on the removal of the superincumbent mound of earth or stones, that urns and human bones were found inside.