COUNTRY BETWEEN THE KOTAH AND PATLI DUNS. 45 



tinted conglomerate. A little north of the suspension-bridge at 

 Garjia (two miles N. of Dikoli) a solitary pillar of the conglome- 

 rate stands up in the middle of the river-bed, and is crowned 

 by a small native temple. That rock marks the northern boundary 

 of the Siwalik conglomerate, which is there dipping at 20 N. by E. 

 The narrowing of the valley in this direction coincides with the 

 assumption of the normal northerly dip. A greater vertical thickness 

 of rock has been cut through, and the gorge is, therefore, narrow and 

 shut in as at Sitabani. This northerly dip conspires with the similar 

 dip in the Gauriagani and Karaungia ridge to the west, whilst to the 

 east it is only retained as far as the commencement of the Kotah dun, 

 when it gradually slackens off to the horizontal. 



North of the temple rock the first exposure is seen in the Suki 

 Rau (18) ; and here we have the Nahan sandstone dipping N.N.E. 

 It is, therefore, clear, from the steady dip of these two formations in 

 one direction (approximately), that the relation between them is of 

 the same nature as between the Nahans and the still older Himalayan 

 rocks (see sections I and IV) ; in other words, it is a case of younger 

 rocks dipping towards older, with a reversed fault as the present 

 result. 



The next reach of the Kosi flows south-east along the boundary 

 between the Upper Siwaliks and the Nahans. On the right bank broad 

 gently sloping chaors of the conglomerate rise from the river-bed 

 and contract upwards into the advanced northerly spurs of the Gau- 

 riagani ridge. Their slopes follow the dip of the conglomerate, just 

 as the line of the ridge follows the strike of the same. This reach 

 is broad and open, the visible expression of the folded flexure (now 

 become a fault) along which the river ran readily, as compared with 

 the difficulty it experienced in cutting through the ridge to the south. 

 Near where the Dhangari (Thunghully) sot (19) joins the Kosi, the 

 boundary leaves the river bed and turns away west. It will be well, 

 therefore, just here to examine the section up that s6t, following the 

 fortunes of the boundary (which we may call the Nahan-Siwalik bound- 

 ary as named by Mr. Medlicott), and afterwards return to the Kosi R. 



( 103 ) 



