S2 MIDDLEM1SS : PHYSICAL GEOLOGY OF SUB-HIMALAYA. 



about the Nahan band, as it is exposed in the Rcimganga R. north 

 of Garral (Gurrul) (27). It represents the same set of beds as extend 

 east into the bed of the Kosi ; but whereas in the latter river they 

 are obscured by gravels, in the more gorge-like Rcimganga and in the 

 Mandal R. (Mundal) (28) they are well seen. Generally speaking, it is 

 much more difficult to get a reliable section through the Nahan beds 

 than through the Upper and Middle Siwaliks ; for their composition 

 does not lend itself so much to observation as that of the two higher 

 Siwalik stages : it very seldom weathers into the same cliff-like 

 sections along the streams. In this case, however, there is a fairly 

 good section along much of the river-bed. 



Commencing near Barsoti on the Ramganga, the first beds of the 

 Ramganga R. (Ram- Nahans met with north of the Nahan-Siwalik 

 2 un 2 a )- boundary are dipping nearly due north at 70 . 



Travelling up the river this is seen to lower to 30 . Near Garral, 

 where the Sanguri sot joins the river, the dip is 6o° in the same 

 direction, although a little to the south of this it is 40 and 45 W.N.W. 

 and N.W. For half a mile north of Garral there is an absence of 

 good exposures, and then there is a solitary dip of 45 S.E. im- 

 mediately followed by 6o° N. E. The N.W. and S.E. dips just 

 mentioned indicate a little irresolution in the normal dip, owing 

 probably to cross-flexuring along the river-bed. It is a cross- 

 flexuring which has tended in addition to widen the river-bed near 

 Garral, and which, in its position at the south margin of these 

 Nahan rocks, holds a similar place in the Nahan zone to the cross 

 flexures in the Kosi and other streams at the south margin of the Upper 

 and Middle Siwalik zones. Thus early we begin to see an homology 

 between the behaviour of the latter zone with regard to the Recent 

 deposits of the plains, and the behaviour of the Nahan zone with regard 

 to it — a point to be borne in mind in view of future discussion. A little 

 further on up stream we appear to pass over a synclinal ; for the dip 

 changes to S.S.W. at 8o° and 70 which continues for some way. We 

 next appear to pass over an anticlinal, the dip becoming 70 N.N.E. 

 This gradually increases to the vertical. At the junction with the 

 ( no ) 



