Chap. II.] the Himalayan series. 25 



The highest beds of the Krol section consist of strong-bedded, dense, blue limestone, 



often closely sub-crystalline. This rock is ■ frequently, and 

 Upper limestone. 



also largely, impregnated with chert in a strangely irregular, 



angular manner, both in continuous strings, and in distinct, angular pieces ; these latter 



are sometimes very small, and give to the rock a pseudo-fossiliferous aspect. I have failed 



to observe any marked boundary between these limestones and the beds below them. On 



the contrary, there seems rather a transition ; there are, not unfrequently, partings of pink 



and blue shale between the thick beds of hard limestone. There cannot be less than 



six or eight hundred feet of these rocks, forming the highest ' member of the Krol 



section. 



The group of strata noticed in the last paragraphs is of great import- 

 ance in the description of the Lower Himalaya. There can be very little 

 doubt that these limestones are identical with that which most persist- 

 ently occurs along the crest of the outer ridges 

 Limestone ridges. 



from the Krol to Masuri and Nairn Tal, and to 



which the greater elevation and the more rugged character of this belt is 

 due. I believe too that many of the ridges and patches of limestone to 

 be met with in the interior of the same mountain region will also be 

 identified with these Krol rocks. Contorted and broken as these rocks 

 are on the Krol and Boj mountains (and I have only attempted to repre- 

 sent in the section the main features of these contortions), this is by 

 far the least disturbed section of them that I have seen, and the only 

 one that leaves their true position with respect to the gritty slate 

 unequivocal. 



Both on the Krol and the Boj these strong, hard rocks are completely 

 insulated upon a base of the thin-bedded, underlying rocks. Denudation 

 is of course the immediate cause of this insulation, but a deeper denudation 



elsewhere does not insulate them in this manner. 

 Krol group. 



These calcareous Krol rocks may, for convenience, 



be spoken of as one group. The coarse quartzite sandstone I will 

 also speak of as the Krol sandstone. The rather abrupt change in 

 the nature of the deposits indicates a considerable change of con- 

 ditions, but I think, we may assert there is here no very great, if 

 any, discordance between the Krol group and the underlying series. 



D 



