The southern area of the sandbank system forming the Caernarfon Bar extending along Morfa Dinlle. Admiralty Sailing Directions dating to 1870 note '...The average breadth of the South sands at low water is about a quarter of a mile, and they carry at high water 9 feet on the highest part, which is about a mile offshore. From thence to the spit end of the sands fall, and for the last halfmile, they are little more than awash at low water springs. There are several patches having scarcely 4 feet over them at lowwater?'

Sources include:
Admiralty, 1870, Sailing Directions for the West Coast of England from Milford Haven to the Mull of Galloway including the Isle of Man, pg73-4
Historic Admiralty Chart 1412-A7, RCAHMW Digital Collections sourced from UK Hydrographic Office (published 1842)

Maritime Officer, RCAHMW, October 2011.