The spit is shown extending some 20km offshore. The southwesterly end is shown with two distinct prongs running east-southeast and west. Admiralty Sailing Directions dating to 1870 note 'This remarkable and extensive reef projects upwards of 10 miles right out to seaward.. to any vessel embayed between it and the Sarn Gynfelin in a westerly gale, escape seawards is quite hopeless. During fine weather the edge of the shoal shows itself by the ripple or overfall of the tide across it, which runs with considerable velocity, and in blowing weather a heavy breaking sea renders the shoal frightfully visible. The Sarn Bardig appears to be generally composed of large loose stones, and though the ridge is narrow, its outer end is an extensive patches of rocks and stones, as if its outer extremity had been doubled back by the violence of the sea. Many of the stones, which dry a foot and a half at low water springs, are three yards across?.'

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, pg53
Historic Admiralty Chart 1411_A5, RCAHMW digital collections sourced from the UK Hydrographic Office and published in 1842
Historic Admiralty Chart 1484_A1B, RCAHMW digital collections sourced from the UK Hydrographic Office and first published in 1843

Maritime Office, RCAHMW, August 2014.