So MIDDLEMISS: GEOLOGY OF HAZARA AND BLACK MOUNTAIN. 



Fig. 5- 



a. a. =■ Granules o l 

 augite included in the 

 darker central part of the 

 plagioclase crystal. 



No - fIti <ty ke a little north of Seree Slier 

 Shah. This rock resembles 5 f^ entirely, and 

 like it exemplifies wonderfully well the in 

 situ breaking-up and change of the augite 

 into an amorphous green mineral. 



No. -gf F resembles the last, but is finer- 

 grained. 



Two examples may now be given of other 

 basic dykes, which differ somewhat from 

 those hitherto described by the fact that the 

 augite as well as the plagioclase is present in 

 irregular crystalline (hypidiomorphic) forms 

 with twinning very common. The last three examples stand apart 

 by themselves. 



No. gf o> d y ke I mile w est of 6,168 ft. peak, north-west of Num- 

 mul, Jhelum valley. A plagioclase-augite titaniferous iron-ore rock. 

 The plagioclase is saussuritic, • giving between crossed nicols only 

 vague uniform polarisation effects. There are traces in the rock 

 of micropegmatite. The augite, unlike that of the dykes already 

 described, seems to have crystallised out comparatively early during 

 the solidifying of the rock. It is largely represented in the slide in 

 long crystals, is of a pale straw colour, very fresh-looking, and gener- 

 ally twinned in the ordinary way, the twinning plane being ioo. 

 Between the two broad twin lamellae there are generally a few very 

 fine twin lamellae interposed. 



No. gfg, dyke south of Sobruh, intrusive among the schists. A 

 similar rock to the last. Some of the plagioclase crystals are quite 

 clear, and others are saussuritic, others again are clear marginally 

 and opaque within. There is also a little quartz and mica in the 

 rock, besides titaniferous iron ore as usual. 



No. 5 ^, dyke among graphitic schistose slates, near Bandee 

 Gundgurh range. In the hand a pale grey compact rock. The micro- 

 scope shews it to be a much altered very fine-grained rock, the original 

 constituents of which cannot be made out. Calcite in veins and epi- 

 dote in granules are secondary products discernible in the slide. 

 ( 80 ) 



