120 Geological features of Bhootan Dooars. [No. 2, 



Sipchuand Jangtsa a remnant comes in as a valley deposit in a 

 narrow high ledge overhanging the Deehu, and at Jangtsa the highest 

 level must be quite 800 to 1,000 feet above it. This level ledge can be 

 traced in a greater or less degree up the valley, being most conspicu- 

 ously marked at the junctions of the main lateral valleys. Looking 

 over the face of the country just described, at the abrupt termination 

 of the conglomerate and clay beds at Tsulcha, &c. and the successive 

 and regular high cut terraces on the east of the Jholdaka, no part of 

 the outer hills that I have seen, gave more the appearance of 

 denudation due to the action of the sea than this: all seemed in 

 accordance with a slow but intermittent last elevation of the land 



The large mass of conglomerates, north of Tondoo, disappear before 

 reaching Chamoorchi: there in the gorge of the Pyim Chu, only alow 

 terrace of transported water-worn materials brought down evidently 

 by that river is seen sloping gradually out into the plain towards 

 Ambari. The hill on which the fort of Chamoorchi stands is of the 

 metamorphic rocks, some of the beds being of a more shaly nature, 

 but all micaceous. Neither here, nor on the right bank of the 

 Pyim Chu was any trace of the tertiary sandstone formation, nor did 

 I see it any where the whole distance to Buxa, not even in the re- 

 entering angle of the large river, the Boro Torsa. In the Chamoorchi 

 Pooar, between the rivers Dahina and Baiti, is a dry flat plain, more 

 or less stony on the surface, open and only covered with grass. It 

 extends as far south as Garkunta and Huldabari Hath: the 

 termination of higher level is very regularly marked also by the 

 sudden rise of numerous small streams that flow due south, through 

 a country where the surface beds are clay and free of pebbles. The 

 distance that the gravel beds extend from the base of the hills, and 

 these streams take their rise, is very regular, and conforms very closely 

 with their contour at 8 to 10 miles. I also noticed that the bouldery 

 character of the beds of the larger streams ceased at the same distance, 

 the Jholdaka, the largest of them becoming at once sluggish, broad, 

 and with a sandy bed at Eamsahai Hath, and the stony bed of the 

 Raiti and Demdema are dry for a long distance ; these outer gravels 

 are evidently the most superficial recent deposits that have spread 

 away from the several hill streams. East of the Baiti a long slope oi 

 gvavel and boulders extends from the foot of the hills some 8 to 10 



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