DISCOVERY SHOAL, or REEF, extends from the West end, in lat. 16°11'N., lon.of 111°32 1/2 E., about E. by N. 5 1/4 leagues, its eastern extremity being in lat. 16°16' N., lon. 111° 46 1/2' E. This long and dangerous reef, is of the shape of an extended oval, with an opening of 1 cable's length on its South side, having in it overfalls from 2 to 20 fathoms; and there is a small opening on the North side. There are no soundings about 20 yards from the reef, and scarcely 2 fathoms water over any part of it, with many spiral rocks a few feet above the water's edge. The Hainan boats come here to fish, from January to May. ^[5]