YSTRAD-DYVODOG, otherwise YSTRAD-DYVODWG (YSTRAD-DYFODWG), a parish, divided into the two townships of Ystrad-dyvodog and Rhigos, in the union of MERTHYR-TYDVIL, hundred of MISKIN, county of GLAMORGAN, SOUTH WALES, 8 miles (N. W. by N.) from Llantriraent; containing 1363 inhabitants. The scenery in this neighbourhood is singularly wild and romantic; and the mountains, which are very lofty, frequently rise abruptly, and almost perpendicularly, from the level ground, and present an unbroken face to the summit, so as to have obtained the designation of the " Alps of Glamorgan." The tourist as he ascends isgradually more and more. delighted, until he reaches "Talcan-y-Byd," or the "forehead of the world," which is one of the most prominent features in the parish: but the roads are very indifferent, and frequently prevent tourists from penetrating into these secluded and romantic scenes. Throughout the valley flews the rapid stream Rhonddii, though of an indifferent appearance, and having only a small volume of water, affords good sport to the angler. The Dines collieries are in the vicinity, whence a communication is formed by tram-roads with the Glamorganshire canal and the Ulf Vale railway. The living is a perpetual curacy, endowed with £600 royal bounty, and £800 parliamentary rant; net income, £85: patron, Rev. J. B. Williams; impropriators, Dean and Chapter of Gloucester. The church, dedicated to St. Tyvodwg, is situated in a valley of the same name, nearly in the centre of the parish. There are two places of worship for Baptists. In the township of Ystrad-dyvodog is a day school, in which 16 children are instructed at the expense of their parents; also a Sunday school, consisting of about 80 males and females, gratuitously taught: these schools are held in a room built by the parishioners, in 1829, and occupied rent-free by a master, who conducts both. The schools in the township of Rhigos are noticed in the article on that place.