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



special mode of formation. There is one strange fact common to all the 

 coarser deposits here ; they contain no trappean debris, or at least so 

 rarely that I happened to observe none, although trap rocks at present 

 largely predominate in the ridge immediately above, and coarse trappean 

 debris so prevails in the actual talus overlying these conglomerates as 

 to be mistakeable for trap in situ. In the conglomerates of the succeed- 

 ing zone of Sub-Himalayan rocks, described in the last few paragraphs, 

 debris of this same band of trappean rock is common. We must at 

 least suppose that at the time of formation of these innermost conglo- 

 merates the fringing belt of limestone, sandstone, and slaty shales was 

 much more developed than now ; but we are scarcely yet prepared to 

 admit that the introduction of the trap was subsequent to the deposition 

 of these conglomerates at Sih, It may be well to mention too that I 

 noticed no debris of pre-existing Sub-Himalayan rocks. The well round- 

 ed pebbles of the lower beds must have come from the inner rocks of the 

 Himalayan series, and, we may perhaps infer, were brought down the 

 gorge of the Beas, but there is no connection at present very manifest 

 between these beds and that river ; the upper beds have been denuded 

 from the position of the actual gorge. These Sih conglomerates are quite 

 cut off from any similar deposits in the other Sub-Himalayan zones ; 

 thus in the Beijnath section we again find only the harder and deeply 

 coloured underlying beds. The position and the peculiarities we have 

 noticed in this isolated patch of rocks render them specially interesting ; 

 the special facts seem to point to their being totally distinct from all the 

 similar deposits to the west and south, yet in general aspect these strata 

 form as great a contrast with the other rocks of this zone as do those 

 outer conglomerates which are so often seen to contain their debris. 

 At Dhurmsala the rocks of this zone are well exposed, exhibiting an 



,,-r,, intermediate and doubtful type as described in the 



at and west of Dhurm- ^ x 



sala - areas east of the Sutlej. To the west, however, 



the zone is very subordinate, being scarcely recognizable at places, as in 



