1S75.] part of the Dafla Hills, Assam. 39 



To the Damudas, quartzitic beds succeed, some very white, but I no- 

 where found an actual contact. On the road to the bridge built by the force 

 above Camp No. 6, a dark green rock is conspicuous by its very trappean 

 appearance : at the bridge a very white quartzite underlies it, dipping 55° SE. 

 These metamorphic rocks have a regular strike SW. — NE., nowhere bet- 

 ter seen than from Zoruputu ; that peak with the peaks of Dorkorpu tu and 

 Shengorh lying in the main axis of elevation in a true NE. — SW. line. 

 The metamorphics seem to pass by degrees into micaceous schists and horn- 

 blendic gneiss (which was noticed 3 miles above the bridge), and then into 

 true granite with large feldspathic crystals, very similar to that of the North 

 Khasi Hills, at the Kollong rock, &e. The peaks of Misa Parbat and 

 Shengorh are of this granite. Near Camp 9, under Nanang's village, the 

 gneiss was very talcose, talc occurring in pieces of an inch square or more. 

 The quartzites, mica schists, &c, probably represent Mallet's " Daling 

 Series." 



River-terraces of Recent Age. — Near the junction of the Tanir juli 

 with the Dikrang, a higher and a lower terrace are well-marked features : 

 they are composed of sand, clay, and large transported blocks, more or 

 less rounded. The lowest is well seen on the left bank about 20 feet 

 above the river bed at Camp 6. The highest, between that and the 

 bridge about one mile above, has a thickness of some 125 feet. Their 

 deposition here no doubt occurred during the period of glacial exten- 

 sion throughout the Himalayan Range, and they would naturally have 

 accumulated more at the junctions of large lateral valleys than elsewhere. 

 The remains of these terraces are to be traced at intervals up the valley, 

 notably at Pachitah, but the highest is not seen in the valley below Na- 

 nang's village and above the junction of the Niiimtay. 



The Burroi Gorge. — At the deep pool where the Tertiary sandstones 

 are first seen on the left bank there is an interesting section. The beds 

 are dipping about 50° towards the plains ; the denuded surface is smooth 

 and undulating, and here not more than 8 to 10 feet above the water level 

 (March). Proceeding up the river about a quarter of a mile to the next large . 

 pool, the same section is again seen, but the upper surface of denuded sand - 

 stone is there quite 15 to 20 feet above the river, shewing a very consider- 

 able slope of the old earth-surface from the hills. On this surface rests a 

 very recent series of iron-coloured sands and gravels, quite 60 or 70 feet 

 thick, nearly horizontal, but the very slight incline is towards the South- 

 ward. These beds abut against the older rocks, which soon commence to 

 rise into well-marked spurs from the outermost range. 



These comparatively recent deposits are no doubt the same as those 

 composing the plateau at Behali Tea-garden, miles out in the plain towards 

 the Bramaputra, and also of the Bishnath plain. About 300 yards below 



