22 M1DDLEMISS: PHYSICAL GEOUOGY OF SUB-HIMALAYA. 



such cases as I have mentioned, in some of the duns, and wherever 

 the former are comparatively undisturbed. These exceptions, how- 

 ever, give a reasonable colour to the supposition that there was never 

 a continuous unconformability between the Recent material, now in 

 the process of forming, and that of the uppermost Siwaliks. Notably 

 in the Pitli dun, and in the Kotah dun at its eastern end, is it impos- 

 sible to separate the one from the other; and I am inclined to think 

 that this is somewhat of, or very nearly, a real sequence, rather than 

 a deceptive conformability. 



The Siwalik conglomerate is composed of much the same mate- 

 rial as forms the present stream-beds. Very seldom it is somewhat 

 angular, but generally it is well rounded. The pebbles are of large 

 size, chiefly of Himalayan rocks, and with a considerable admixture of 

 earthy sand, of buff or dark yellow colour. Near Dhanaor Chaor 

 on the Nandhaur R. there occur Siwalik conglomerates, often verti- 

 cal and almost entirely composed of large blocks of Nahan sandstone. 

 Many clay and loamy bands, of brown and yellow colours, are inter- 

 bedded with the ordinary conglomerate. The latter increase in quan- 

 tity low down in the formation, and are often. studded here and there 

 with pebbles. False bedding is very common ; and the rock is hard- 

 ened in places by a deposit of lime between the pebbles. Over the 

 area in which I have worked, I have seen very little horizontal varia- 

 tion in the material forming the conglomerate. An attempt to estab* 

 lish a difference between the pebbles at the E. and W. extremities 

 failed, with the exception that in E. Kumaun the presence of large 

 numbers of well-preserved granite and trap pebbles is clearly due to 

 the existence of the parent-rocks immediately north of the sub-Hima- 

 layan zone. Seeing that their general source must have been the 

 higher Himalayan range, and that lateral uniformity is the chief thing 

 noticeable in that range, so far as its composition goes, this is exactly 

 what we should expect. The following is a list of the commoner 

 pebbles,between many of which innumerable passage-forms exist : — 



jt- , . f Purple and white and grey quartzite . * most common. 

 ' I Purple and grey slate common. 



( 80 ) 



