The harbour is deep, but shut in by mangrove swamps; and though the water a few miles up is fresh, it is only a tidal river; for, after ascending some seventy miles, it was found to end in marshes blocked up with reeds and succulent aquatic plants.

As the Luawe had been called "West Luabo," it was supposed to be a branch of the Zambesi, the main stream of which is called "Luabo," or "East Luabo." The "Ma Robert" and "Pearl" then went to what proved to be a real mouth of the river we sought.
The Zambesi pours its waters into the ocean by four mouths, namely, the Milambe, which is the most westerly, the Kongone, the Luabo, and the Timbwe (or Muselo).

When the river is in flood, a natural canal running parallel with the coast, and winding very much among the swamps, forms a secret way for conveying slaves from Quillimane to the bays Massangano and Nameara, or to the Zambesi itself.

The Kwakwa, or river of Quillimane, some sixty miles distant from the mouth of the Zambesi, has long been represented as the principal entrance to the Zambesi, in order, as the Portuguese now maintain, that the English cruisers might be induced to watch the false mouth, while slaves were quietly shipped from the true one; and, strange to say, this error has lately been propagated by a map issued by the colonial minister of Portugal.
After the examination of three branches by the able and energetic surveyor, Francis Skead, R.N., the Kongone was found to be the best entrance.

The immense amount of sand brought down by the Zambesi has in the course of ages formed a sort of promontory, against which the long swell of the Indian Ocean, beating during the prevailing winds, has formed bars, which, acting against the waters of the delta, may have led to their exit sideways.