Metamorphic and Plutonic Rocks at Omeo. 117 



(h.) At this place the schists are much jointed, and the 

 foliation is not marked ; yet, on looking at the rocks in 

 mass, they can be seen to be contoi'ted in structure. A rude 

 foliation dips at 52° to N. 20° E. There are traces of granite 

 veins with schorl. The hand sample of this rock is of a 

 light buff colour, with a schistose character produced by 

 alternations of lig^ht and dark-coloured foliations. Examined 

 by means of the pocket lens, the light-coloured portions 

 appear to be a minute mixture of felspar and quartz, and 

 the dark-coloured portions to be the same with a large 

 proportion of a dark-coloured mica. Throughout this surface 

 larger plates of muscovite are visible. 



This preliminary diagnosis is borne out by an examination 

 of a thin slice. The main mass of the rock is composed of 

 quartz and mica, with a somewhat less amount of felspar in 

 grains. In places these grains are aggregated together, and 

 are surrounded by grains of quartz larger in size. These 

 felspar aggregates suggest that they are the broken 

 fragments of one individual. The grains of quartz are 

 much separated by flakes of muscovite and of magnesia 

 mica, the latter being much chloritised. This chlorite 

 polaiizes with faint tints. The quartz grains include fluid 

 cavities, and also numbers of minute, rounded, brown and 

 colourless microliths. Iron ores and a few broken and 

 cavernous crystals of tourmaline complete the list of 

 component minerals. 



(i.) The schists here are thick bedded, dipping S. 65° W. 

 at 78°. In a hand sample the appearance is much that of 

 the last described rock, but it is rather darker in colour, and 

 perhaps not quite so minutely crystalline. 



In a thin slice the rock is seen to be mainly composed of 

 interlocking grains of quartz, which are full of rounded 

 microliths, both of a brown colour and colourless. Brown 

 mica flakes are plentiful among the grains of quartz. In 

 places, what may be called the ground mass of the rock, is 

 not quartz, but felspar, in which are included the quartz 

 grains. Most frequently this felspar has been converted 

 into an aggregate of minute flakes of mica of a yellowish 

 colour. In addition to these components there are a few 

 yellowish-coloured tourmaline crystals, which, as in other 

 samples of these rocks, have been eroded and wasted since 

 their crvstallisation. 



(k) the schists at this place dip N. 20° E. at 81°, and 

 are traversed by small aplite veins. The sketch. Fig. 3, 



