Original blazon: Ar. a chief sa.
Crest: A cock crowing ppr.
(Scotland : Sir William de Airth of that Ilk, mentioned in Ragman's Roll as one of the great proprietors who swore fealty to Edward I., died without male issue. His eldest daughter and co-heir conveyed the estate of Airth, in marriage, to Robert Bruce, ancestor of the Bruces of Airth).
Source: Burke's General Armory (1884)