36 Godwin-Austen — On the Geology of [No. 1, 



The strata dip about 20° NW., and consist of thick-bedded fine sand- 

 stones with strings of water-worn pebbles here and there, but no conglo- 

 merate was seen ; they weather on the higher ridges into spheroidal masses 

 indented with small holes, in a precisely similar manner to the upper sand- 

 stones of the Burrail range. The most conspicuous beds are of a very pale 

 grey colour with black grains. Pieces of lignite are commonly found in situ 

 and lying in the beds of the water-courses. The ravines are bounded by 

 very steep sides, and are deep and gloomy. Looking from Dihirhi Parbat 

 westward, the fringing range of the sandstones is well seen, rising at Groru- 

 sutia or Peak 1 of the Gr. T. S. into a sharp scarped point 3,319 feet high, 

 but the ridge descends here and there on the line of strike to below 1000 

 feet. It presents the same feature all along of a steep scarp towards the 

 plains, and of a slope dipping 20° — 25° NNW. towards the main mass of the 

 mountains on the north, from which it is separated by a broad valley or 

 " dhun" drained by the Pomah. This dhun is cut up by numerous ravines 

 and low ridges all buried in dense forest. 



To the eastward, 3 miles from Dihirhi Parbat, the sandstone ridge is 

 much subdued. A change takes place in the strike of the mountain mass, 

 and a broad forest-clad plateaUj much intersected by ravines and about 200 

 feet above the plains, extends as far as the gorges of the Dikrang at Har- 

 matti. On this side, the Borpani and Dikrang on their SW. — NE. courses 

 represent and take up the continuation of the Pomah Dhun. At Harmatti 

 is seen another quite recent deposit, in an alluvial plateau of sand, clay, and 

 boulders, on which land for a tea-garden has been taken up. It corre- 

 sponds to similar terraces in the Western Bhutan Duars, as those on the 

 Jholdaka, &c, but is nowhere more than 30 to 40 feet above the river bed, 

 and is found fringing the older rock slopes for some distance up the valley 

 and to the eastward. It lies against a broad extent of very low intricate 

 hills, which, from this towards the east, are a conspicuous feature. The 

 very hurried examination I was able to make of these beds near Harmatti 

 shewed them to be ferruginous-coloured sandstones and thick conglo- 

 merate beds resting on fine blue grey sandy beds dipping 5° to South-east- 

 ward. No lignite was seen in situ, but rolled pieces were common in the 

 bed of the stream, evidently brought down some distance. At Harmatti 

 similar beds dip 15° SE. ; they appear to me to represent the newest beds 

 of this Tertiary series, here extending out into the plains beyond the strike 

 of the 1st or Dihirhi Parbat line of elevation. This line is taken up again 

 east of the Dikrang by alow ridge which bounds the river on the SE. as far 

 as the great bend it takes 10 miles above the junction of the Borpani. 



Leaving the stockade at this junction, the winding bed of the Sibjuli 

 is followed, and this \\ miles farther is joined by the Niosi, a much larger 

 stream. In the bed of the last, the gravels are found to be a great mixture 



