The northern channel, called the river of Watelai, is about a quarter of a mile wide at its entrance, but soon narrows to abort the eighth of a mile, which width it retains, with little variation, during its whole, length of nearly fifty miles, till it again widens at its eastern mouth.

Its course is moderately winding, and the hanks are generally dry and somewhat elevated.

In many places there are low cliffs of hard coralline limestone, more or less worn by the action of water; while sometimes level spaces extend from the banks to low ranges of hills a little inland.

A few small streams enter it from right and left, at the mouths of which are some little rocky islands.

The depth is very regular, being from ten to fifteen fathoms, and it has thus every feature of a true river, but for the salt water and the absence of a current.