18 GEORGE D-S- DUNBAR ON 



The valley of the Dihang presents three distinct topographical zones. 1 Away to 

 the north the river foams through a succession of canons cut in the crystalline rocks, 

 with mountains towering high on either side, that gradually expand into a deep-cut 

 valley. Below this the valley widens and the slopes down to the river become gentle. 

 This is the heart of the Abor country, densely populated, with all the hillside system- 

 atically cleared for cultivation. Further down the river, the valley once more contracts 

 and, with high partially-cleared spurs far above it, the Dihang finds its way through 

 steep gorges into the plains. The purple shale existing in beds of considerable extent, 

 the boulders brought down by the rivers from the metamorphic rocks further north 

 and the weathering that creates throughout the country somewhat formidable ob- 

 stacles to rapid progress are, to the unscientific observer, the main geological features 

 of the lower zone. Of this weathering the hills from Tapi Nari up to Kunung, in the 

 Galong country, that look like great ant-hills connected by razor-edged ridges, 

 furnish a good example. But the most interesting feature that has come within my 

 personal experience rises from the bed of the Siemen above Koiyu. This is the Dupe 

 ridge. It runs for about nine miles hardly ever much more than three yards across, a 

 serrated wall of clay. The ridge is bounded generally by precipices some hundreds of 

 feet in the sheer, fortunately clothed, as a rule, with vegetation, and extends, water- 

 less, at an elevation of over 5,000 feet, from the Siemen river to the gentle descent 

 into the Sipu valley. The total waterless tract, including the ascent to and descent 

 from the ridge, is fourteen miles. Another interesting physical feature was found up 

 the Dudu, a tributary of the Siemen, below Kadu. For about f mile this stream flows 

 through a rock passage varying from about 4 to 20 feet across, with walls of rock 

 rising to a height of 100 to 150 feet on either side ; trees arch and interlace their 

 boughs overhead. Iron was found here in considerable quantities. 



Few sheets of standing water have been found, none of them large enough to rise 

 to the dignity of a lake; one near Parong, in the depth of the jungle, is about 

 70 yards across in winter. The nature of the country does not, as a rule, lend itself 

 to lakes of any size. 



The most remarkable feature of the fauna of the Abor-Galong country is the 

 „ , _, total absence of the elephant , an animal that roams in 



Fauna and Flora. " » 



large herds through the Darla country and to the south of 

 the Lohit. Elephant's teeth were found near Rotung which, from a geological point of 

 view, were quite recent, but the animal has entirely deserted the hills that lie between 

 the Subansiri and the Dibang. The reason for this is not apparent. The conditions 

 are similar along the frontier and the Daflas are certainly not less persistent as 

 hunters than the Galongs and Abors, who can hardly therefore be assumed to have 

 exterminated them. Whilst elephants are plentiful in the Digaru-Mishmi country, 

 the Northern Mishmi highlands are possibly too steep for them, amazingly capable 

 though they are of surmounting almost precipitous ridges. I once saw two elephants 



1 These conditions obtain westwards to Akaland : to the north precipitous country on an immense scale guards the 

 Tibetan passes; below this are a series of fertile straths and valleys shut off from Assam by the comparatively 

 low, but difficult, foot-hills. 



