It is in 12 degrees 29 minutes South, and 123 degrees 56 minutes East, by chronometer.
Captain Heywood in 1801 saw the following reefs.

The centre of one in latitude 12 degrees 48 minutes, and longitude 124 degrees 25 minutes; and the other in 13 degrees 29 minutes, and 124 degrees 5 minutes.
HIBERNIA SHOAL, seen by Mr.Samuel Ashmore, Commander of the ship Hibernia, consists of two small sandbanks in the centre of a shoal, four miles in extent, lying in an east and west direction.

It is in latitude 11 degrees 56 minutes, and longitude 123 degrees 28 minutes, by chronometers.
Mr.Ashmore also saw another shoal in 1811, the particulars of which are detailed in the following letter.
"The north-east end of the shoal, fell in with on the 11th June, 1811, by a good noon observation, is in 12 degrees 11 minutes South, longitude by chronometer 122 degrees 58 minutes 30 seconds (allowing the south head of Port Jackson to be in 151 degrees 25 minutes 25 seconds).

To the westward of the barrier of black rocks, that presented themselves to our view, were several sandbanks, the highest of which, on the east end, appeared to have some vegetation: the rocks in general were six or eight feet above the water and the surf broke violently on the North-East and South-East points in view.

The shoal trends in a West by North direction for six or seven miles," It is distinguished on the chart by the name of ASHMORE'S SHOAL.
SCOTT'S REEF (see Horsburgh volume 1 page 102) was discovered by Captain Heywood, R.N., in 1811: the north-west end is in latitude 13 degrees 52 1/2, and longitude 121 degrees 59 minutes; thence it extends South 16 degrees East for eighteen or nineteen miles to the north-east point, in latitude 14 degrees 1 minute, and longitude 122 degrees 16 minutes; the south extent was not ascertained.