APPENDIX. 



On theories of mountain formation. 



In every country the first object of geological investigation is the chronological co-ordins?' 

 tion of the rock-formations. Next to this the question of greatest interest in the region to which 

 the foregoing memoir refers is that of mountain-structure. Had my personal knowledge of 

 the Himalayan rocks been much more extensive than it is, or could I have obtained from 

 other sources a corresponding knowledge of a large portion of the Himalayan region, I might 

 have made an attempt to solve the problem of the general structure of the system. As it is, 

 any such attempt must have been premature. I have done little more than to group some 

 of the data and to point out the bearing of my observation upon existing theories of moun- 

 tain-structure. The necessary incompleteness of my work must be my excuse for appending 

 to my observations a sketch of what I understand these theories to be. I shall moreover 

 thus fulfil a special object in a treatise intended primarily for India, namely, to afford as much 

 as possible collateral and preliminary information for the assistance of those who may be 

 willing to aid in the extension of a scientific knowledge of the country : for lack of some such 

 suggestions many an intelligent observer has expended his labours almost to no purpose. 

 And even to the general student of geology an abstract of the prevailing opinions upon mouu- 



tain formation may not be amiss ; for, that our knowledge on 

 Our knowledge of mountain , . . . , . , . . , , , , 



formation very deficient. this important subject is in a very scattered and unsettled state, 



is clearly enough indicated by the scanty notices which our 

 latest and most approved manuals of geology take of it, — we find high authorities still advo- 

 cating incompatible explanations, — the mode of origin of the mountain areas that have been 

 most carefully studied is still doubtful. The doubt and obscurity to which I here refer is 

 however readily explained by the consideration that the phenomenon in question is a result 

 of underground agencies, of which the conditions are so difficult of investigation. 



Besides the intrinsic difficulty to which I have just alluded, there is another, and an 

 extrinsic impediment to our knowledge of mountain-formation, 



,ra P Ty faSi0aWiU ' Phy8ieal ° e0 " to which l nmst briefl y aIlude - It is ' the habit that prevails 

 of confounding two very distinct aspects of nature, the actual 

 and the retrospective — the habit of not distinguishing between facts regarded as elements ia 

 the existing harmonies of nature, organic and inorganic, and facts regarded as the productions 

 of past activities. The former view is that belonging to physical geography, the latter to 

 physical geology. Both sciences have suffered from the mistake, — physical geography has been 

 thereby encumbered with difficulties that do not belong to it, and physical geology has become 

 infused with a looseness that is most prejudicial to its progress. Observations that may 

 be valuable contributions to the former science may have a very insignificant bearing upon 

 the latter. For example, hypsometrical details (the exact determination of elevations) form 



