DESCRIPTIVE GEOLOGY : GENERAL CONSIDERATIONS, 285 



have ventured upon in this memoir all tend in my opinion towards 

 the same conclusion. But it is necessary here to do what I neglected 

 to do in my earlier memoir, namely, to guard myself against miscon- 

 ception by defining what I mean exactly by such a statement. 



Ever since our great pioneer in Himalayan geology, Mr. Medlicott, 

 first examined and described the Sub-Himalaya in his memoir (Mem. 

 G. S. of I. Vol. Ill); and since the Revd. O. Fisher wrote his far- 

 seeing ' Physics of the Earth's crust' it has been gradually becoming 

 evident to all who really examined the question in detail that the 

 Himalaya are and have been in a constant state of change : a state 

 of elevation along the main axis and depression along the mountain- 

 foot, with intermediate zones of crushing, crumpling, and over-riding 

 along shear and thrust planes. This is so evident that if one desired 

 to be very particular one might say literally that the Himalaya of to- 

 day are not the same as those of yesterday. But such a view of the 

 matter would be valueless. Hence, in speaking of the Himalaya of a 

 past geological age or epoch we mean, or at least I mean, that old 

 representative of them which held about the same position and acted 

 functionally in the same way as does the mountain-range going by 

 the name of Himalaya to-day. It may not always have been of the 

 same height as the Himalaya of to-day. It may sometimes have 

 been represented by long parallel coast lines, or by archipelagoes 

 with chains of mountainous islands following similar parallel lines, 

 but that it kept certain original features, and that a mountain core 

 recognisable in its unity, persisted through Tertiary, Secondary, and 

 possibly into Palaeozoic times, I have no doubt. 



But whatever ultimate conclusion be come to in the future regard- 

 ing these mountains, the moral of my recent work in Hazara seems 

 to be that the more any part of the range is studied in detail the 

 more impossible does the task appear of accounting for the presence 

 of that lofty and complicated mountain mass, by any theory of sudden 

 upheaval, whether by sudden we mean an upheaval occupying one or 

 other age of the Tertiary period, or whether we take it in its still 

 more wild and literal sense as being Post-Pliocene. 



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