82 MIDDLEM1SS : PHYSICAL GEOLOGY OF SUB-HIMALAYA. 



no conglomerate, but the sand -rock is continued across the valley in 

 a reversed fold, the axis of which follows beneath the line where the 

 Siwalik conglomerate must once have been. In explaining the first 

 reversed fault in the Ramganga-PeUni section, this state of the rocks 

 has been alluded to. The thickness of the sand-rock north of the axis 

 is very nearly equal to that to the south. The beds likewise harden 

 away from the axis, and there is only a small amount of faulting or 

 thrustino- along what is very nearly an uninjured sigma-flexure. The 

 lower bend of this sigma-flexure embraces the strata between the 

 Sona N. and the plains ; the middle limb is made up of the inverted 

 sand-rock and Nahan sandstone between the Sona N. and the Kali- 

 harpal (Kalee Hurpal) ridge (39) to the north, only slightly torn along 

 the i unction of those two formations ; whilst the upper limb is formed of 

 the strata on the north-east slopes of that ridge. This state of things 

 not only proves the former extension of the sand-rock over that ridge 

 to the north, but it also indicates that the first thrust plane or reversed 

 fault in the Ramganga originated in a sigma-flexure, and did not ab 

 initio begin as a thrust plane. 



Continuing up the Sona N. above Dhansi Chaor, we find at 

 Hathi-Khund itself the Siwalik conglomerate once more retained in 

 a thin bed along the axis of the flexure, which has now become almost 

 a normal (unsymmetrical) synclinal, with the fault reduced to a mini- 

 mum, or perhaps even absent altogether for a short distance ; for the 

 dips in the Kclnia sot (40) on the north side of the axis are all S.S.W. 

 at high angles of 70 &c, none of them being inverted, and there is 

 very little discrepancy in hardness between the uppermost Nahans 

 and the lowermost beds of the sand-rock stage. This dipping S.S.W. 

 of the sand-rock stage, followed by a younger series in normal order, 

 is an exception to the rule as previously formulated (from the section 

 up the Pelani R.), that there is never a regular ascending series from 

 north to south in anything but the youngest beds. Its exceptional 

 character is further shewn if we ascend to the head of theTimals6t (41), 

 an affluent of the Sona N.; for we there find the strike of the Siwalik 

 conglomerate carrying it directly up to the high scarp of Nahan sand- 



( MO ) 



