Correspondence — Mr. C. S. Middlemiss. 93 



PHYSICAL GEOLOGY OF THE SUB-HIMALAYA. 



Sir, — May I be permitted a few remarks in reply to Mr. 

 Mediicott's review of my memoir in this Magazine for October, 1890 ? 

 I cannot attempt to answer objections of a theoretical nature, or of 

 purely local interest to us in India ; but on one or two points where 

 I think Mr. Medlicott has mistaken my words or my meaning I 

 would say a word or two. With regard to the fault at Jirinjala in 

 my horizontal section No. V., which Mr. Medlicott says " seems 

 uncalled for," I must plead that the fault is nevertheless there, as 

 plainly visible in the natural sections exposed as in my drawn 

 section. It is not a fault inserted to meet a theoretical requirement. 

 The firm lines in all my sections indicate facts (when not otherwise 

 stated in the text), whilst the dotted lines alone represent inferential 

 conditions of the rocks. The large scale, four inches to the mile, 

 maps would have fully satisfied Mr. Medlicott on this point had 

 they been pi'ocurable. In speaking of, and representing, the main 

 boundary, the Nahan-Siwalik boundary, and others, as faults, I hope 

 I have not " ignored their primary and most interesting character " 

 (see p. 118-123 of my memoir). They are certainly faults noio — 

 sometimes with miles of throw or thrust (see p. 66) ; hence to lay 

 them down on the map as natural boundaries, because they originally 

 grew out of such, would be a very grave error. It would be akin 

 to representing the lie of the beds as horizontal, for the reason that 

 they were originally deposited so. In addition it must be remembered 

 that the present faulted boundaries are not absolutely, but only 

 approximately, coincident with the original limits of deposition. 

 In some cases, as at Jirinjala, the original boundary, and the approxi- 

 mately coincident faulted boundary, are both present, and need a 

 separate and distinct method of representation. 



The difference between section VI. and section IX. with regard 

 to the position of the Nummulitic and Tal beds on the subjacent 

 rocks, is owing to the thinning out of the Massive Limestone, or to 

 its previous erosion. This is plainly illustrated in the map accom- 

 panying my paper on the '* Physical Geology of W. British 

 Garhwal " (Records G. S. of I. vol. xx. pt. 1). To state, as Mr. 

 Medlicott has done, that my " facts in favour of an earlier plication 

 of the Himalayan rocks are only quotations of wholesale differences 

 of strikes in that region," is to simply misquote me, as the first 

 words on page 127 of my memoir will make evident. 



In criticising Mr. Mellard Reade's theory of mountain-formation, 

 as applied to the Himalaya, I did not impute blunders to Babbage 

 and Herschel " in the elements of science." What I did was to show 

 that Mr. Reade's application of the Babbage-Herschel theory in the 

 case of great sedimentation was unsound. Again, though the Babbage- 

 Herschel principle may involve the idea of a " fluid substratum," 

 as Mr. Fisher's theory does, the same is not true of Mr. Reade's 

 theory, with which I was concerned. The latter expressly assumes 

 the earth to be solid. 



0. S. Middlemiss. 



Abbottabad, Panjab, I2lh December, 1890. 



