Note 228 — Chapter V · THE FINÉ OR SEPT IN IRELAND, AND THE TRIBE IN WALES.
Reading edition
Ancient Laws of Wales, pp. 96, 97. It is not quite clear whether the length of an Erw is thirty times its breadth, or thirty times the long yoke. In the latter case the Erw would contain only 1706 square yards, or rather more than the third of an acre.