This gulf is thickly strewed with islands and reefs: a group off Cape Voltaire was seen by the French and named by them the INSTITUTE ISLANDS, the three principal of which, of flat-topped shape, are called Descartes, Fenelon, and Corneille; besides these the Montesquieu Group, and Pascal and Condillac Islands, were distinguished.

On the eastern side of the gulf, near the shore, are OSBORN'S ISLANDS, which are high and rocky: the southernmost is remarkable for its steep, precipitous form, and for its resemblance to Mount Cockburn in Cambridge Gulf.

There is also a conspicuous high bluff on the principal island, which appears to have been seen by the French.
In the offing is CASSINI ISLAND; it is rather low and level, and surrounded by cliffs and rocky shores: on the eastern side are four sandy beaches, which are very much frequented by turtle: a reef projects off its north end for a mile and a half.

The anchorage is good near the island, but the water is very deep.

The situation of its centre is in latitude 13 degrees 55 minutes 5 seconds, and longitude 125 degrees 42 minutes.
PORT WARRENDER is an excellent port, and affords good anchorage in the bay round Crystal Head, in which a vessel is quite land-locked; but equally secure anchorage may be had for five miles higher up the port, in from four to seven fathoms, mud.