STRATIGRAPHICAL ELEMENTS : CRYSTALLINES, ETC. 57 



has been powdered and drawn out into an eye, and wherever pebbles 

 occur the same distortion has happened to them, or they appear first 

 to have suffered a slipping of one part over the other. The above is 

 what may be seen with the eye on every foot of exposed rock on the 

 hill-side. With the aid of microscope slides the same distinctive 

 features can be more clearly made out. A specimen \ mile west of 

 the "S" of Sobruh Gulee in addition to shewing the above mylonitic 

 structure has the quartz grains in many places completely, and in 

 others marginally, altered into a polysynthetic aggregate comparable 

 to those figured by McMahon (Min. Mag., Vol. VIII, PL II) in the quartz 

 of the quartz-felsite of Tusham hill. Another specimen of quartz-schist 

 i mile north of Teer village, ^f-g, possesses a slightly mylonitic structure 

 visible with the microscope, undulose extinction of the quartz grains, 

 and white mica waving round the latter. A pale grey quartzite from 

 nearGhazi north of the Gundgurh range, ¥ fy, is an ordinary quartzite 

 with a few grains of microcline and triclinic felspar. 



(3) More intensely metamorphosed rocks, presumably representa- 

 tives of the Slate series in the main. 

 Having seen that so far as the southern margin of the great 

 crystalline and metamorphic area is concerned, the rocks shew many 

 stages of incipient metamorphism and that they can be individually 

 recognised as being altered lower members of the normal historical 

 sequence of formations described in the earlier portions of this 

 chapter, it will now be my object to take for description examples 

 of the more thoroughly crystalline foliated rocks such as are found 

 only in the more northern parts of the district, namely, Agror, Khagan, 

 and the Black Mountain. Among these strata the metamorphism is 

 so complete that there is no longer any direct evidence from indivi- 

 dual samples and sections that the rocks are true representatives of 

 what w 7 ere originally sedimentary deposits. The only reasons for 

 supposing them to be such are of an indirect nature, though very 

 strong. Briefly stated, the reasons above all others for the above 

 supposition are (1) that it is impossible to draw any hard-and-fast line 



( 57 ) 



