258 MIDDLEM1SS: GEOLOGY OF HAZARA AND BLACK MOUNTAIN. 



dykes, the younger series (Infra-Trias and cl Tanols ") 



is only penetrated by the basic dykes. 



(3) That as regards disturbance with crumpling of the strata, 



the thin- bedded older metamorphic series is the one that 

 has suffered most severely along the outer margins of 

 the area where the granite veins are absent or of minor 

 importance ; but that further inwards towards the higher 

 ranges the same rocks have been (in a measure) protect- 

 ed from contortion and folding on a large scale, owing to 

 the great resistance offered by the thick and massive 

 sills of gneissose-granite. Thus it is that the higher hill 

 masses exhibit gentle dips in the foliation of their schists, 

 and also in regard to the junction planes between them 

 and the granite, which, as has been frequently stated, are 

 generally parallel to each other ; hence it is also that the 

 higher isolated crystalline massifs exhibit a qua-quaversal 

 dip all round them of their component strata, and hence 

 it is that there are such great variations in the strike, with 

 the occasional persistence over relatively large areas of 

 N.W.—S.E, strikes (as in the Black Mountain). 



(4) That such an arrangement is not peculiar to this part of the 



northern backbone of India, but has been noticed and 

 described by me in previous papers on the crystalline 

 and metamorphic rocks of the Himalaya, especial refer- 

 ence being made to the Chor mountain, Kaloghari 

 (Lansdowne) and Dudatoli ; whilst Mr. Medticott long 

 ago commented on the same peculiarity. 



(5) That as regards the younger metamorphic series the crump- 



ling and folding, though fairly intense, is distinctly less 

 than that of the older series wherever the two are found 

 together. 



(6) Comparing the zone as a whole with its neighbour zone to 



the south (the Slate zone) we must notice, above all, the 

 absence of any authenticated evidence for any rocks 

 younger than the Infra-Trias— whilst they only occur 



( 258 ) 



