102 SUB-HIMALAYAN ROCKS OF N. W. INDIA. [CHAP. IV. 



appear in every ease, and these lines are carefully mapped. The con- 

 trast I have just indicated between the relations of the two groups in 

 the east and in the west of our district suggests a difference in conditions 

 of disturbance as affecting these two regions. For the reasons above 

 stated, I will separate the description of these two regions, adopting 

 the east end of the Pinjore Dun as the. line of demarcation. In each 

 I will, to some extent, combine the description of the two groups : they 

 are mutually illustrative. 



The relation of the Nahun group to the older rocks has been already 



noticed in the third Chapter. I have there stated 

 Relation to the older 



rocks. mv opinion, that the junction is primarily a line 



of original contact, possibly modified by subsequent faulting. This view 



of the case will be exemplified by the facts to be discussed as to the 



relation between the Nahun and Sivalik groups; and it will be again 



examined with reference to the structural conditions of the whole region. 



The opinions that have been published regarding these Sivalik and 



Nahun rocks are various and contradictory, hav- 

 General relations of . • .. „ 7 



Nahun and Sivalik rocks, mg been in most cases formed from unconnected 

 Previous notices. . . „ 



observations, and without relerence to previous 



notices. Thus, Herbert in 1826 (his memoir, however, was not pub- 

 lished till 1812, in Vol. XI, Jour. As. Soc, Ben.,) 

 remarked the resemblance of the massive sandstones 

 of the Sivalik hills to the similar rocks (of the Nahun group) at the base of 

 the Naini Tal hills, and conjectured their identity, colouring them as one 

 band on his map. He assumed them to be of Saliferous age, and having, 

 by an equally groundless assumption, supposed the sandstone of Delhi to be 

 Old Red, he actually made a number of borings in the Doab in search of coal. 

 Cautley in 1836, (Trans. Geol. Soc, London, 2nd Ser., Vol. V.) from 

 fossil evidence (vide p. 15), identified some of the 

 hisrher beds of the section at Nahun with the 

 bottom beds of the Sivalik range. From the uniformity of the northerly 



