60 MIDDLEMISS: PHYSICAL GEOLOGY OF SUB-HIMALAYA. 



again, the amount of dip being high as before. The direction of dip 

 now becomes gradually due south, and, ultimately, when half a mile 

 E.N.E. of Simal parao, east of south ; and the road then follows the 

 stream bed along the axis of another synclinal. The brown sandstones 

 of the Nahans are here varied by a large amount of purple and cho- 

 colate coloured shales, which indicate the proximity of the base of 

 the stage. The dips on each side of the synclinal axis are high, at 

 angles of 6o°, ;o°, and 8o°. At the point where the Delidunga (32) is 

 joined, the change in the strike has become even more pronounced, 

 the dips now being N.W. and S.E. on each side of the axis. The 

 lower parts of the Delidunga, where it opens into the Pa"tli dun, are 

 not very well exposed ; but there seems to be some uncertainty 

 of dip owing to a flattening out with faulting which brings in 

 younger Nahans to the south. It is to be noticed that, coinciding 

 with the change in the strike of the Nahan beds, from W.N.W. — 

 E.S.E. to W.S.W. — E.N.E., the southern edge of the Nahans changes 

 in the same way. We thus have the north-west portion of the P3tli 

 dun bounded by low Nahan sandstone cliffs, which take a direction 

 W.S.W. — E.N.E. The Pa*tli dun, therefore, owes its northern con- 

 vexity to the oblique meeting of these two directions of strike, and 

 to the strike faults which accompany them. At the same time, as 

 a result of the change of strike, there ensues a greater widening of 

 the Nahan zone towards the west : a spreading 'out of it, and flatten- 

 ing out of the dips, which allows the sand-rock stage, as already 

 stated, to make a second appearance among what has hitherto been 

 exclusively a Nahan zone. 



If we now turn our attention to the southern slopes of the P£tli 



dun, we observe that the Siwalik conglomerate 

 Pdtli (Patlee) ddn. ' S 



which torms them has no corresponding change 



of dip and strike. Its southern boundary keeps an unflinching direc- 

 tion W.N.W. — E.S.E.; and the dips both at the west end of the low 

 range, and further east, can be seen by the maps to be N.N.E. 

 at angles varying between io° and 20 . The sand-rock stage, which 

 comes conformably beneath the conglomerate, also has the same 

 ( "8 ) 



