miles further, where our examination ended. This last may be considered
as a submarine extension of the barrier, which probably reappears again
above water, and passing to the northward of the Calvados Group, reaches
as far as the northern entrance to Coral Haven, enclosing nearly all the
high islands of the Archipelago. The expanse of water inside when not
occupied by land usually exhibits a depth of from 15 to 30 fathoms, with
numerous sunken patches of coral, and several reefs which partially dry
at low-water. The shores of the islands also are generally protected by
fringing coral reefs, the largest of which is that extending off the west
and south side of Piron Island to a distance of seven or eight miles,
with a well defined border towards Coral Haven.

At the western portion of the Louisiade Archipelago the reefs seen by us
exhibit great irregularity of outline, continuity, and width. Some are
linear reefs, others atolls* more or less distinct in character, and the
remainder are usually round or oval. Viewed as a whole they form an
interrupted chain, with numerous deepwater channels, which terminates in
the West Barrier Reef of the chart but is connected with the coast of New
Guinea by a bank of soundings, with, probably, a well-defined margin.
Many low, wooded islands are scattered along this line. I know of no
distinguishing feature presented by the coral reefs of the Louisiade
compared with those which I have seen elsewhere. One remarkable
occurrence, however, connected with them, may be mentioned. While passing
in the ship the most northern point of Rossel Island, I observed upon the
reef, about a hundred yards inside its outer border, a series of enormous
insulated masses of dead coral rising like rocks from the shallow water.
The largest of these, examined through a good telescope from the distance
of half a mile, was about twenty feet in length and twelve in height,
with a well-defined high-water mark. It formed quite a miniature island,
with tufts of herbage growing in the clefts of its rugged sides, and a