This is a Wilsons pattern. Scottish Tartans Society notes: "First reported by MacGregor Hastie in 1934. The sample was found to match a similarly styled piece in the Wilson's samples housed in the collection at the Smith Institute in Stirling. The conclusion drawn was that a 'Dunbar District' tartan had been in existance since around 1840, providing an alternative to the Vestiarium sett (#1472) published in 1842."