The whole of the Papuan Gulf may be regarded as unsafe for vessels to visit. The water is always muddy, and reefs cannot be seen. Moreover, there is little depth of water for miles from the shore, very often not more than two fathoms, and heavy rollers are constantly coming in. From Redscar Head eastwards the South Coast is skirted almost continuously by a reef, an outlier of the great Australian Barrier Reef. This reef extends from the shore, at a distance of some five to six miles, and the numerous indentations afford excellent harbours and anchorage. Along the whole of the North-East Coast, from East Cape to Mitre Rock, are numerous large harbours. The most important harbours, however, which would afford anchorage to any considerable number of vessels of a large size are Port Moresby, Orangerie Bay, Milport Bay, and South Cape. At some of these, however, landing for small boats is difficult, on account of the fringe of reef. The navigation along the whole coast is difficult, and no vessel can travel at night.
There are a large number of rivers in the Protected Territory, and the whole of it, with the exception of the district around Port Moresby, appears to be well watered. The largest rivers are those which drain the basin of the vast level region which begins on the west side of the Gulf of Papua. The largest of these rivers is the Fly River, which rises some hundreds of miles in the interior. It is supposed that many of the smaller rivers are mere branches leading into the Fly. Owing to the action of the south-west monsoon, which blows during the healthy season, the mouths of these rivers are silted up with sand and mud, and are unnavigable. This is especially the case in the Aird River, which it is only possible to enter during the north-east monsoon, or unhealthy season. On the South-East Coast the rivers are numerous, and the soils on the banks fertile. As, however, the elevated land is near the coast, they are small in comparison with those in the west. The North-East Coast appeared to be well watered, and several rivers of considerable size were seen. In Dyke Acland Bay, where there is a vast tract of level country, densely wooded, intervening between the coast and the highlands, which are very distant, the mouth of a very large river was discerned. This river was not marked on any map.
In Milne Bay, two rivers, not mentioned in any map and apparently unknown, were discovered and explored. The first river (native name Davadava) was discovered in the north-east of the Bay, and was explored for a distance of about six miles. The banks were steep and precipitous; vegetation rank; timber; depth from eight to twelve feet; small bar at its mouth, navigable for a small steamer. It is comparatively a small river, rising in the mountains near the coast. The other river (native name Hadara) was a very large one, and
