50 SUB-HIMALAYAN ROCKS OF N. W. INDIA. [CHAP. II. 



be equally well seen about Baot, in the valley to the north of the 



ridge over Runi. 



Along the north side of the Sutlej valley the position of the limestone is better defined 

 than on the south. There is an excellent section in ascending 

 from Malgi to the Dhamun Nag summit. The independent hill 



of Balu, rising nearly as high as Dhamun Nag, from which it is separated by a deeply cut 



gap, is formed of the massive limestone. The Sutlej at Malgi 



Malgi and Dhamun Nag. ,.,,,,.,,. .,i T , ,■ •, 



runs over thm-bedded, pink limestone, with slaty partings, and 



having a dip of 70° or 80° to north 10° east, but exhibiting also frequent sharp foldings on the 

 same strike. These beds reach to about half the height of the hill, where the dip is reduced 

 to about 60°. On account of the contortions in the lower part of the section, the exact 

 thickness cannot be ascertained ; it can hardly be less than 1,200 or 1,500 feet. The thick 

 siliceous limest one succeeds, and at the summit it inclines at 40° to north-north-east. There 

 must be atdeast one thousand. feet of it. Along the descent to the gap leading to the Dhamun 

 Nag the limestone is found to be overlaid by brown and dark blue slates, and with them is a 

 band of slaty limestone. These thin-bedded rocks are, of course, more or less contort- 

 ed, but they have a marked general northerly dip. At the gap there is a strong rib of 

 quartz along the strike, and immediately north of it, on the rise to Dhamun Nag, schistose 

 slates appear, much veined by quartz, and having a lower and steadier dip in the same 

 direction as the rocks to the south. Along the ascent they become more metamorphic, 

 and at about a third of the height the coarse gneiss shows, its massive beds dipping at 40° to 

 north 10° east. 

 As it appears in plan, the section suggests the existence, along the gap, of a faulted 



junction. But besides the fact that this more abrupt junction, 

 Junction not a simple fault. .... . 



with a separating vein-rock, is an exceptional appearance along 



tins boundary, we have at this place other facts to throw doubt on such a suggestion. 



The feature already described on the south of the Chor, as indicating the general underlying 



position of the less altered rocks, is equally well marked in the similar instance of this 



boundary, and no where better than in the valleys to the east and west of the Dhamun Nag 



mountain. On both sides the junction forms a well marked angle up the valley. Moreover, 



there is much likelihood that the slates, and slaty limestone which, in the Dhamun Nag 



section, certainly rest upon the great limestone and conform to its condition, are the same 



beds as those noticed about Runi in a similar position, but at that place most certainly 



underlying the siliceous schists, and partaking of their condition. 



With slight variations the section along the north of the Sutlej valley to the westward, as 



far as Gairu summit, is similar to that I have described south of Dhamun Nag. The strike 



in that direction becomes more northerly. In some places, as in the great cliffs below 



Odittana, the gneissose rocks reach to within a few dozen yards of the limestone. At the 



southern bend of the Sutlej, at Boh, the thin pink limestone and variegated slates underlie at 



80° to the north-east ; the gap of Bntwara is formed in them. Along the western shoulder 



and on the summit of Gairu the massive limestone, with its 

 Gairu mountain. . 



associated pink and white quartzite-sandstone is greatly rolled 



about, often dipping east and south-east ; along the ridge to the east dark shaly slates 



with much trap-rock are similarly disturbed. This run of trap-rock is very steady in this 



