He [Robert Marmion] married Avice, daughter of Gernegan, son of Hugh DE TANFIELD (b), through whom he obtained Tanfield and several other manors of the Richmond fee. He died probably in 1241, certainly before 23 October 1242. His widow was living in 1284. [Complete Peerage VIII:514-6, (transcribed by Dave Utzinger)]
(b) In the Pipe Roll of 16 John, Robert Marmion, the younger rendered account of 350 marks and 1 palfrey, having paid 40 marks and 20 marks for palfreys. Avice, who had been committed to Robert Marmion's custody, was still under age in 1221 (Curia Regis Roll, Easter 5 Hen III, mm. 2 d, 3). Her ancestry is indicated in an entry in the 'Fountains Chartulary', vol i, p. 20, where Hugh son of Jernegan and Jernegan his son occur as witnesses to a notification by Roger de Mowbray to Roger Archbishop of York, circa 1154-81. This latter Jernegan, probably identical with Gernegan son of Hugh living 1176-77, may have been her great-grandfather rather than her father. A Hugh son of Jernagot, possibly her grandfather, granted land in Tanfield to Fountains Abbey in 1193 (Chartulary, p. 21). From her grandmother Maud, the mother of her father Gernegan, she inherited land in Manfield (Assize Roll 1046, m. 26). There are several references to Avice Marmion during her long term of widowhood. Described as Avice Marmion, daughter of Gernegan son of Hugh de Tanefeud (Tanfield), she quitclaimed to Fountains Abbey all right in a meadow in Jarnewyc (Yarnwick), and granted land in Sinderby in frankalmoign (Fountains Chartulary, vol i, p. 370). She also quitclaimed to Fountains all right in four carucates in Melmerby, reserving to herself and her heirs suit of court at Thorneberg (Thornbrough, par. West Tanfield); to this deed Sir William Marmiun, doubtless her son, was a witness (Idem, vol. ii, p. 513). . . .