202 PROCEEDINGS OF SECTION 0. 



From tte Vailala to the Purari, the hilly country is nearer the 

 coast, and extends for a short distance westerly, and then north-westerly 

 towards and beyond Hiperi. Leaving Hiperi, and trending north-east 

 for 7 miles, we pass into flat and swampy country, and, with the 

 -exception of one or two small rises, do not meet the hilly country 

 again until we approach Luria, near Borki. 



The chief waterways in the Gulf Division are the Purari, Vailala, 

 Tauri, and Lakekamu Rivers, and the smaller rivers near Kerema. 



The Purari, Taviri, and Lakekamu have formed deltas at their 

 mouths, and, to a smaller extent, the rivers o£E Kerema. 



The Vailala, which is of immediate importance, takes its source 

 in the mountainous country north, near the German boundary, and 

 is fed by the Ivovo (not shown on the map), Ivori, and Dahiti Rivers, 

 the first flowing from the north-west and the two latter from the east. 

 The Vailala has a very sinuous course through the hilly country above 

 Akauda, and meanders very extensively from that village to the 

 coast. It is a fine broad river, varying in width from 60 to 300 yards, 

 and is navigable for at least 70 miles. This river, as far as Akauda 

 and a little beyond, can carry a boat drawing 2 fathoms, the only 

 obstructions being the large sand bar at the mouth and an outci'op of 

 rock, easily removed, 2^ miles above Akauda. 



General Geology. 



The chief rocks met with in the portion of the Gulf examined are 

 grits, sandstones, limestones, and mudstones, all carrying fossil 

 remains in part. The grits vary in grain from very fine to very coarse, 

 the individuals being ujigular fragments of quartz, limestone, igneous 

 rocks and other sedimeiitaries cemented, in some cases, by lime, and in 

 others by a softer material carrying a large proportion of black sand- 

 The chief occurrences for this rock are the Cupola and Shoulder Hill, 

 near Kerema ; the Bluff, where they outcrop on the beach beneath 

 the recently raised coral limestone ; Aumana Point, and at a few 

 isolated localities north of Hiperi, near Borki ; and on the southern 

 slopes of the range north of Mount Namo, nearWashdirt Creek, I have 

 seen fossils in these grits at each locality. The sandstone varies in 

 grain, but is usually fine and mixed with lime. In a great many 

 instances it passes into a psammitic mudstone, carrying fossil mollusca 

 and carbonized plant remains. The sandstone as a rule occupies the 

 prominent rises in the hilly country, whilst the mudstone is 

 found in close proximity to it, occurring on the slopes and creek beds. 

 The mudstone and sandstone are by far the most extensively developed, 

 each carrying many bands of hard fossiliferous limestone. The 

 sandstone varies in composition from the pure quartz-grained varieties 

 to those containing fragments of eruptive rook and rauscovite. Itl 



