Translation according to P. W. Joyce:
Cloonruff in Galway; Cluain-ruibhe [-ruwa orrivva], meadow of sulphur. See vol. ii. p. 372 [reproduced below].
Sulphur. Native sulphur is found in the limestone of Oughterard in Galway, so that it can be picked out of the stones in the bed of the pretty little river that flows through the village, when the water is very low. O'Flaherty (Iar. C. p. 53) records that in a great drought in 1666 and 1667, "there was brimstone found on the dry stones [in the bed of the river] about the bridge of Fuogh". From these sulphury deposits he states "it was commonly called Owan Roimhe, Brimstone River; and this name is now modernised to Owenriff. This word ruibh [riv], sulphur, is found in a few other names, but it does not occur often. Revlin in the parish of Killymard, near the town of Donegal, probably received its name for the same reason as the last: - Ruibh-linn, sulphur pool or stream. Moneenreave in the parish of Inishmagrath in Leitrim, the little bog of the sulphur.