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. It is ninety-seven miles due East from the situation assigned to Dampier's Rocks. The Cartier also struck upon a shoal hereabouts, and Captain Horsburgh seems to think that there is little doubt of Scott's Reef being the same that Dampier saw, as well as that on which the Cartier struck.
ROWLEY'S SHOALS consist of three separate reefs, the westernmost is the Imperieuse, the middle Clerke's, and the north-easternmost the Mermaid's. The Imperieuse is ten miles in length from north to south, and its greatest breadth five miles: it is surrounded by very deep water and near the eastern edge, in latitude 17 degrees 35 minutes, and longitude 118 degrees 51 minutes, are some dry rocks. Clerke's Shoal (south end in latitude 17 degrees 28 minutes, longitude 119 degrees 18 minutes) extends to the north-west, and probably joins the Minstrel's Shoal, which is described below, and, if this is the case, trends North-North-West 1/2 West for seventeen miles. The south end of Mermaid's Shoal is in 17 degrees 12 minutes South, and 119 degrees 35 minutes East, and extends to the northward for seven miles; but its termination in that direction was not seen. The edges of all these reefs are steep to; and no bottom was obtained with one hundred and eighty fathoms. Within the reefs, however, there is a bank of soundings of the depth of from one hundred and seventy to one hundred and twenty fathoms. (See Horsburgh volume 1 page 101.)
MINSTREL'S SHOAL (see Horsburgh's Supp. page 52) its north-east end is in 17 degrees 14 minutes South, and 118 degrees 57 minutes East, or 5 degrees 28 minutes East by chronometer, from the coast of New Holland in latitude 23 degrees 10 minutes South. The longitude of that part of the coast by my survey, is 113 degrees 42 minutes; this will make the Minstrel's Shoal in 119 degrees 10 minutes, which agrees very well with Clerke's Reef, the centre reef of Rowley's Shoals, of which it is certainly the north end; so Captain Horsburgh also supposes.
A ship called the LIVELY was wrecked on a coral reef in about 16 degrees 30 minutes South, and 119 degrees 35 minutes East.
RITCHIE'S REEF, or the Greyhound's Shoal. The situation of this reef is recorded by Captain Horsburgh (see Supp. page 38) to be in latitude 19 degrees 58 minutes, and longitude 114 degrees 40 1/4 minutes; but, by a letter published in the Sydney Gazette by Lieutenant Ritchie, R.N., the commander, it would appear to be in 20 degrees 17 minutes 40 seconds, longitude by lunars 114 degrees 46 minutes 6 seconds.
ROCK OFF VAN DIEMEN'S LAND.