After parking by the phonebox cross over and go through the turnstile and on to the footpath,follow the path with the hedge on your left, after 50 yards a gap appears go through and up the hill to the nearest telegraph pole. Just at the foot of the pole is the first stone 8ft long and positioned in an east-west line,pointing through the hills and on to Anglesey, almost covered in moss and ivy but nearly free of gorse it's next to impossible to find unless you know where it is. Unless it's been excavated and proved to be a burial chamber I'd be inclined to see it as a fallen standing stone, what's the chances of there being two chambers of so different styles so close to each other?, then again what do I know.
From here follow the telegraph poles southish into the trees, It's only 50-60 yards away from the other stone and slightly downhill, your first view of it will be from behind the capstone.I spent a good hour or two chopping back the undergrowth of brambles, and removing all the deadwood. The capstone is fifteen feet long and rests on just one upright, it is aligned N.W-S.E and you could just about get in so long as you lie down. The chamber seems to have at one time been built into a dry stone wall because at least two denuded and broken down walls converge on the site.
Two blokes with a truck and the right gardening equipment could in just one day change this place from unknown and overgrown to delightful and charming ,somewhere you might expect to see fairies,two or three trees removed and the views would open right up.Having said that despite the scrub and tree cover this place remains very nice and good to find.
The first time I came here it was a total surprise expecting to see just the overgrown boulder, when I saw the obvious chamber and it's capstone I felt like Indiana Jones in the Raiders film when he says about the bad guy" he's dgging in the wrong place".Untill someone else comes here I will pronounce this place MINE
If you do come bring the machete and have at the brambles.
The roads are confusing but follow the os map and youll be OK ,park by the phonebox and on the other side of the road is a footpath proceed and turnleft off the path uphill, go past ironmans stone and into the trees the chamber is well hidden ,but the capstone is huge and obvious propped up on one orthostat.no view is possible because of dense vegatation,flippin CADW just dont seem to care sometimes
This site isn't easy to find, the roads round here are very confusing. We asked a friendly local for directions and he got straight in his car and led us to the spot - what a dude. The site is a disappointment, very little is left, and what there is lies overgrown. The location however is good, with a view stretching from the Snowdonian mountains right out to sea.
The only existing cromlech in the parishes of Llanllechid and Llandegai is situated in the upper part of the parish of Llandegai, near a small farm called Ffynnonbach. It goes locally by the name of "yr hen allor" (the old altar), and tradition, as usual, ascribes its erection to the Druids; and the use to which it is said to have been applied, is indicated in its being called an altar. But that the cromlech was a mere burial-place, has long since been settled. The cap-stone measures in breadth 5 feet; in length, 14 ft. 5 ins.; in thickness, about 1 ft. 6 ins. throughout.
More on the state of the stones in 1867, along with associated finds, in volume 13, series 3 of Archaeologia Cambrensis, viewable at the Internet Archive.