The National Gazetteer of Great Britain and Ireland - 1868
"SUBBERTHWAITE, a township in the parish of Ulverston, hundred of Lonsdale South of the Sands, county Lancaster, 8 miles N. of Ulverston. It includes a vast tract of waste land, interspersed with rocks and woodland. There is a slate quarry. The Duke of Buccleuch is lord of the manor."