STRATIGRAPHICAL FEATURES. 45 



valley, which is traversed in every direction by veins of this rock 

 varying in thickness from half an inch to many yards. There I also 

 noticed the change which has taken place in the lithological aspect of 

 the mother-rock, which from a clay-slate (as is seen in adjoining less 

 altered parts) has been altered into a garnetiferous, sometimes 

 micaceous schist, highly contorted and plicated. 



The fact that this granite occurs chiefly in long lines, coinciding 

 with the general strike of the flexures which form the Himalayas, 

 seems to point to the probability that the granite masses with thei r 

 neighbouring numberless veins have intruded along lines of fissures 

 and dislocations formed along lines of greatest tension. Indeed, we 

 see along the boundary of the haimantas with the crystalline rocks in 

 the Niti area, that there the entire thickness of schists and semi- 

 altered schists of the vaikritas which elsewhere intervene between 

 the granitic gneiss and the sedimentary strata, is absent altogether, 

 but instead of it, I found great granite intrusions which penetrate even 

 the quartzites and slates of the haimanta system, whilst further north- 

 west the granite swells out to enormous proportions. I think it very 

 possible that there exists a long line of dislocation which partially 

 cuts out the older slates and schists of the vaikritas. 



Besides the extensive granitic intrusions already noticed eruptive 



rocks of another kind play an important r61e in 



BcLSIC 61*11 otivc rocks 



Central Himalayan geology. A series of basic 

 rocks, amongst which serpentine, diallage, epidofe and basaltic 

 varieties are prominent, occurs throughout the Lower and Central 

 Himalayas, and are in very strong force both in Western and Eastern 

 Hundes. They, like the granite, I believe, appear along lines of dis- 

 locations and here and there enter the neighbouring strata as dykes. 

 In some places these rocks have effected immense changes in the 

 lithological character of the neighbouring formations; for instance 

 the nummulitic rocks of Hundes (north of Niti) have in a large 

 measure been converted into a semi-crystalline formation, which one 

 would naturally identify with some of the lower palaeozoics (hai- 

 mantas) which they resemble, were it not that on the one hand their 



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