42 
From Port Moresby to the foot of the Astrolabe, the staple for- 
mation consists of sandstones, shales and limestones, often inclined at 
high angles to the horizon. The basement bed 
of the volcanic rocks was found to rest upon 
the up-turned edges of reddish shales at an 
altitude of 2,060 feet above sea level, the lower 
most member of the series consisted of a fine 
grained much weathered volcanic ash. From 
base to summit, this portion of the range con- 
sists of nothing but an enormous thickness of 
coarse volcanic conglomerate. On reaching 
the edge of the tableland, and proceeding to 
the village of Tabouri, some miles distant, the 
track passes over nothing but coarse con- 
glomerate. From the village to Warino Creek, 
which rises in the range to the south, nothing 
but sheet upon sheet of horizontal volcanic 
conglomerate is visible. The pebbles of the 
conglomerate are subangular, and naturally 
vary very much in size ; in composition they 
vary but little, and consist for the most part of 
conglomerate. Between the Warino Junction 
and the Falls of the Laloki, the river forms a 
series of picturesque rapids, due to the water 
falling over the outcrops of some of the 
irregular bands of fine ash, which are inter- 
stratified with the coarser materials. Many 
fine perpendicular cliffs in the Laloki Canon 
give a good idea of the structure of these 
enormous ash beds. At the Laloki Falls the 
river, which previously has flowed over the sur- 
face of these horizontal beds, suddenly plunges 
over the perpendicular escarpment, 300 feet in 
height, and flows down a magnificent canon for 
over a mile, after emerging from which it enters 
the comparatively open country. I climbed, 
accompanied by three natives, to the verge of 
the canon, at a place called Babera by the 
guides, in the hope of being able to trace the course of the escarpment 
northwards, but a Scotch mist effectually prevented my so doing. 
Looking down the valley from my coign of vantage, a bold scarp, 
seveial hundred feet in height — Hombron Bluff — was seen to form the 
north-eastern end of the Laloki Canon. Prom Tabouri the country to 
the south-east was traversed ; to the divide between the headwaters of 
the Laloki and the Kemp Welch Rivers, the whole section proved to 
