Chap. IV.] nahun and sivalik groups. 121 



Laika hill, over Shilani on the west, offers a striking instance of this. 



On the south of this hill, in a tributary of the Markunda, near the village 



of Meintappel, there is an excellent section : . the finer conglomerates 



with sand and clays have a steady dip of 10° to north ; from this they are 



seen to turn up without a break, and within a radius of ten yards, to a 



dip of 80° to south, and this dip obtains throughout the whole hill-mass, 



through an enormous thickness of strata in a descending section. On 



the north of Laika, the descending section from the Shilani conglomerates 



passes right across the base of the hill, the northerly strike going nearly 



at right angles to that of the strata on Laika ; on the east and west the 



dips are almost as transverse as on the north. In such cases as these one 



must introduce faults, and be content with very vague conjectures as to 



the immediate causes of them. West of the Eoon the dip of the Sivalik 



strata is much more regular, at a low angle to north-north-east, up to 



the very contact. Here, in every section that I examined, the abnormal 



superposition of the older rocks is as well marked as in the Markunda. 



The Sivalik range, south of the Dehra dun, is for the most part formed , 



on the northern side of a great irregular anticlinal 

 in Sivalik range. 



flexure. The local dip varies very considerably, 



but there is a line along the south base of the chain, inside which the 



dip is invariably to some point between east and north ; near the axis 



the dip often amounts to 40° and 50°, but in all the sections it lowers 



gradually to where it passes into the more or less horizontal strata of 



the dun, in a manner quite similar to the type section of Simbuwala. 



At almost every point along the southern base, we find the beginning 



of the reverse southerly dip, and in two places, one on the right bank of 



the Jumna, and the other on the right bank of the Ganges, the section of 



the rocks on the south of the anticlinal is nearly complete ; and in both 



we observe the very opp'osite tendency to that described on the north, 



namely, in a direction from the axis the dip increases rapidly almost 



to the vertical. Thus we have a well characterised example of what 



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