De Riodal
de RIODAL—XI—de Ridal, de Rydale, Riddell, Riddle, Ruddell, Ruddle; Norman 'de Ridal,' i.e., of Ridal (?), some spot in England. 'de Rydale' and 'Rydalagh' occur in old documents relating to Co. Limerick, where Ruddle is a well-known surname. See Riodal.
Alphabetical Index to Irish Surnames