STRATIGRAPHICAL ELEMENTS : CRYSTALLINES, ETC. 65 



liquid mass of the acid magma whilst still in a semi-molten or viscid 

 condition. While acknowledging the great weight due to the opinion 

 of such an authority on Himalayan petrology, I am reluctantly 

 compelled nevertheless to dissent from his view and to conclude 

 that the greater part, if not all the foliation and linear arrangement 

 of the ingredients of the gneissose-granite, has been due to a super- 

 induced action, to a form of dynamic metamorphism acting on the 

 rock since the time it became a solid stationary mass. My reasons 

 will be evident by themselves from what I shall say in the sequel. 



The following is a brief outline of the 

 features shewn by the types A, B, & C referred 



Microscopical de- 

 scriptions of typical to above. Good examples of all of them may be 

 examples of A, B, & C. ,,,.,, ,, , . r-.., r^, 1 



well studied between Makranai and Ril, Black 



Mountain : — 



C. Granitic type. In this the rock shews no subsequent lami- 

 nation of the minerals and no eye structure. The coarsely granular 

 crystalline ground-mass is thickly dotted with porphyritic felspars 

 of normal shape, the outlines alone being a little blurred. They are 

 oriented in every direction indiscriminately. A good example of 

 this type is to be seen one mile N. E. of Mansehruh along a little 

 ridge of tors standing up out of the plain ; also at Diliari and near 

 Sarnbalbut in the Black Mountain. 



B. (1) Augen ; (2) Porphyritic augen. The terms here explain 

 themselves. The granular crystals present in the rock when non-por- 

 phyritic and the porphyritic crystals in the latter are no longer of an 

 irregular or a regular crystalline form. On the contrary, the former 

 are drawn out at their extremities into eye or lens shaped bodies, but 

 still separated one from the other, whilst the latter (the porphyritic 

 crystals) have their corners rubbed away, the material being re- 

 deposited at right angles to the pressure, thus producing a very 

 similar large eye or lens shaped body. Examples occur on the road 

 from Makranai to Ril. 



A. (1) Tabular-foliated ; (2) Lenticular -tabular foliated. 

 A. (2) is a very common form. In it the previously formed eyes 

 of quartz and felspar have been so dragged out, or rolled out 

 F ( 65 ) 



