Near the island there is a rocky rapid with narrow passages fit only for native canoes; the fall is small, and the banks quite low; but these rocks were an effectual barrier to all further progress in boats.

Previous reports represented the navigable part of this river as extending to the distance of a month's sail from its mouth; we found that, at the ordinary heights of the water, a boat might reach the obstructions which seem peculiar to all African rivers in six or eight days.

The Rovuma is remarkable for the high lands that flank it for some eighty miles from the ocean.

The cataracts of other rivers occur in mountains, those of the Rovuma are found in a level part, with hills only in the distance.

Far away in the west and north we could see high blue heights, probably of igneous origin from their forms, rising out of a plain.
The distance from Ngomano, a spot thirty miles further up, to the Arab crossing-places of Lake Nyassa Tsenga or Kotakota was said to be twelve days.