26 mallet: geology of darjiling and western dfars. 



The Tertiaries and Daling beds are seen within two or three hun- 

 dred yards of each other at the head of the 



Sivok naddi. 



Sivok naddi. The intermediate space is nearly- 

 blank, but in one or two spots doubtful Damuda sandstone, dipping 

 nearly vertically, is seen. Even if the whole space be occupied by 

 Damudas, the band is greatly reduced in breadth here. 



In the Tista, however, it is again expanded, and attains its maxi- 

 mum breadth of a mile. The strata are consider- 



Tista river. 



ably contorted. For the last few hundred yards 



of its course, the Riyem flows along the crest of an anticlinal, the beds 



dipping away at either side at angles of 60° — 80.° Ascending the 



Tista dips are found to north at 60°, east at 80°, west at 80°, and 



finally west at 60°, close to the junction with the Dalings. Crushed 



coal-seams a few inches thick are numerous in both rivers, and at 



the mouth of the Riyem there is a bed of coal 3 feet 6 inches thick mixed 



with carbonaceous shale and sandstone, and dipping north-north-west at 



70°. Some of the Damuda sandstones here, as weil as in other sections, 



are more or less calcareous ; sufficiently so to give rise to deposits of tufa 



under favourable circumstances. 



The only rocks seen between the Tertiaries and Dalings in the 

 Lesu are indurated crushed massive sandstone 

 obscurely bedded, the junction of which is not 

 seen with either of the above. 



Near the head of the Rumtek, a small feeder of the Lesu, which it 



joins from the east side, the stream cuts through 



Rumtek naddi. -, o • i i t • ,-, -,~n 



an 18-mcn coal-seam, dipping north 15 west, at 



80°. On the hill side, above a small watercourse, there is a seam of pure 



coal 7 feet thick, dipping north-north-west at about 20°, and in another 



ravine close-by the following section is visible. The beds are un- 



( 26 ) 



