GENERAL CONSIDERATIONS. 139 



shewn that the views he enforces by these Himalayan examples are 

 still more completely borne out by the results obtained by me. 



His first reference is introduced by way of shewing that the crust 

 of the earth in mountain regions has suffered lateral compression as 

 distinguished from vertical up and down movements. He writes, 

 p. 43, — " To take an instance of the mode of action of lateral pressure, 

 " we may refer to the very instructive comparison between the Alps 

 "and the Himalayas which has been made by Mr. Medlicott and pub- 

 11 lished in the ' Journal of the Geological Society'. 1 He there shows 

 " that the reversed apparent faulting by which the older rocks of the 

 *' central chain of the Himalayas appear to overlap the younger of the 

 " Nahan range, and these again the still younger rocks of the Siwalik 

 " range, is due to lateral pressure, which must have compressed the 

 "rocks horizontally, at least at two distinct epochs since the central 

 11 chain was first elevated." From what I have said in previous chapters 

 on the subject of the five reversed faults in the Pelcini R., and their 

 formation at successive periods, it will be seen that at least in that 

 locality five distinct compressions have acted, resulting in horizontal 

 thrusts of the growing mountain mass towards the plains. The Sub- 

 Himalayas, therefore, are really richer in examples of lateral pressure 

 than Mr. Fisher supposed when he wrote his book. If he had pro- 

 duced it a few years later, he would have been able to add the very 

 striking examples of horizontal thrusts that have lately been worked 

 out with great patience and skill in the north-west highlands [of 

 Scotland by Prof. Lapworth, Messrs. Peach and Home, and other 

 officers of the Geological Survey of Scotland. Still, in drawing that 

 inference from the Himalaya, he drew one which further work among 

 those mountains has only succeeded in making the more apparent. 



His second reference includes the Himalaya as evidence against 

 the theory of the entire solidity of the earth. The instability of 

 the earth's crust, the shifting of the crust towards a mountain range, 

 and the sinking of deltas and other regions of deposition, go to shew 



1 Vol. XXIV, p. 34. 



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