132 SUB-HIMALAYAN ROCKS OF N. AV. INDIA. [CHAP. IV. 



The composition of the middle group from the Guggur westwards is 



_. . ...» very different from what we have seen in the Nahun 



General composition of J 



middle group ; rocks, and far less simple. We scarcely even find 



a lithological representative of the lignite sandstone, unless it be among 

 the doubtful rocks of the region of the Beas. The rocks which, north of 

 the Pinjore valley, form an intermediate band between the Sivaliks and 

 the Subathu group, have a closer resemblance to the latter than to the 

 former ; the thick-bedded sandstones are of a dark colour, often coarse, 

 and are well hardened ; beds of clay are very frequent. The most not- 

 able difference, however, is that in the Sutlej we find the middle group 

 surmounted by a great thickness of conglomerates that cannot be con- 

 founded with those capping the younger group to the south. The outer 



rocks of this great series of deposits, and which we 

 and of Sivalik group. . . m . ,.„'-., 



can, within general limits, continue to distinguish 



as Sivalik, consist as before of massive conglomerates, coarse and fine, 



alternating with, and overlying, thick beds of sand and clay. 



In the Mungrud the whole middle band is about a quarter of a mile 



,,.,,. . B ,, . broad; and, the strata being nearly vertical, this 



Middle group of Sutlej ' ' s> J . .> 



area - also represents their thickness on this section. 



In the Sursulla, near Kalka, the belt is nearly two miles wide ; for the 



greater portion of it there is a broken section 

 Sursulla. 



of coarse gritty clays, and red and purple, hard, 



earthy sandstone, coarse and fine ; the dip is not very steady, varying 



from east 15° north to 50° north ; it is high throughout. For a few 



hundred feet next the outer boundary, a massive, 

 ? a fourth group. . 



clear gray sandstone shows itself, having an oppo- 

 site underlie to the rest of the section, being also greatly crushed ; this 

 rock is not exposed in every section, there is none of it in the Mun- 

 grud, but it is noteworthy as being possibly the only true representa- 

 tive of Nahun rocks here, the rest belonging to a distinct period of 

 formation, and which' a more minute study may separate as a fourth 



