138 SUB-HIMALAYAN ROOKS OF N. W. INDIA. - [CHAP. IV. 



believe to have existed more or less as such upon the sea-bottom of the 



Subathu period, have produced the difference we observe in the rocks ? 



The gravest objection to such a supposition is the persistent absence of 



any sign of the easily recognized bottom nummulitic beds, no matter 



how great the upheaval, or of any of the subjacent black slates, no 



matter how great the faulting or crushing. 



The commencement of the Pinjore dun is structurally very analogous 



'. . „ to what we have seen that of the Kyarda dun to 



Sivaliks of Pinjore and J 



Una : foe. Massive bands of boulder conglomerate are 



introduced at the top of the Sivalik group capping the range in the 

 Baso-ati summits, where they have the same moderate dip as the under- 

 lyino- strata. The boundary of the Nahun group takes a sudden bend 

 towards the debouchure of the Guggur, and the conglomerate slopes down 

 along it into the dun, forming on the right bank of the river a perfectly 

 undisturbed valley-deposit resting against the steep hill of the middle 

 rocks. These Basgati conglomerates are composed 

 of debris of the Subathu sandstones, and have 

 probably been deposited by the Guggur in an early stage of its exist- 

 ence. This river passes through the low outer range by a wide open 

 gorge south of Kalka ; on both sides the conglomerates have a dip of 

 30° to north-east, and, as before, the same beds appear in the dun at a 

 short distance, and quite undisturbed, at the confluence of the Sursulla 

 and Guggur. The contrast is more striking than in any examples I could 



give in the Dehra dun, and it requires the most 

 important junction in ° * 



the Sursulla ; distinct evidence to make any one believe that 



these .undisturbed beds are not simply a dun deposit, the fact of litholo- 

 gical resemblance being manifestly of very little weight. This evidence, 

 however, is at hand, and 1 ; as if to suit the occasion, it is the most satis- 

 factory of any that I have seen. In continuing up the Sursulla, these 

 boulder beds last undisturbed for some miles ; but within half a mile of 

 the inner boundary they have an equally steady dip of 15° towards 



