ERYRYS (ERW-YRYS), a township, in the parish of LLANARMON, hundred of YALE, county of DENBIGH, NORTH WALES, 4 miles (E.) from Ruthin. The population is included in the return for the parish. This township, which takes its name from Yr Hen Gyrys o I&l, a collector of Welsh proverbs in the eleventh century, forms the northern portion of the parish, and is situated in a narrow valley through which the river Alyu flows it is bounded on the western side by the lofty Clwydian mountains, which separate it from the Vale of Clwyd, and on the eastern by a range of hills, nearly equal in height, separating it from Flintshire. The latter exhibit several projections of limestone rock, highly impregnated with lead-ore, the mines of which were productive for many years, but are now only partially worked, in consequence of the low price of that metal. In 1828, however, a very powerful steam-engine was erected, for pumping out the water, and great benefit has been anticipated from the success of this project, by affording employment to many of the inhabitants. The road from Caergwrle to Ruthin passes through the township, nearly parallel with the river Alyn, which is here crossed by a bridge, and then continues its course towards the latter town between two lofty mountains, called Moe Venni and Moel y Cyw, each upwards of one thousand seven hundred and fifteen feet above the level of the sea: this gap is called Bwlch Agricola, from an opinion that it was traversed by that Roman general on his route to Mona. On an artificial mound near the foot of the former stood the castle of built by Owain Gwynedd, in 1148, of which the only remains consist of the rampart and fosse surrounding it.