96 The Sedimentary, Metamorphic, 



These massive schists are in places porphyritic by reason 

 of small masses of felspar and quartz, or of one or other, which 

 form the centres of bulges in the schist foliations. In other 

 respects a sample of this rock, when examined under the 

 microscope, did not differ materially from that which I have 

 just described. 



35. — At this place the rocks are distinctly crystalline- 

 granular, having a " granitic" appearance. They are 

 traversed by winding veins of a reddish-coloured aplite, and 

 by narrow veins of epidosite. 



I examined samples of these -two rocks. A slice of one of 

 the most " granitic" samples I found to be a noncrystalline 

 rock, formed of triclinic felspars, quartz, and chlorite. The 

 last-named mineral is in large, ragged masses, of precisely 

 the character of the chlorite after the Haughtonite mica of 

 Noj^ang. The original mica is now all converted, but I can 

 feel no doubt that it was the first-formed mineral after 

 magnetite. The felspars came next in order of consolida- 

 tion. They are in very compound crystals, with higher 

 obscuration angles than any which I have had to record 

 yet in this paper. I made measurements in the zone 



OP — oo P cc, between 3° 30' and 30° 30', and in one section 



which was near the plane oo P oo, the angle was as high as 40°. 

 In this section, which was otherwise simple, there were a 

 few short twin lamellae interposed in one corner, not pre- 

 cisely in accordance with the Pericline law. 



The quartz was last formed, and differed in no respect 

 from that of the quartz-mica diorites of the district. A 

 slice from a second sample from this place shows a well- 

 marked crystalline-granular compound of felspar, with much 

 dark- coloured hornblende and chlorite and some quartz. 

 The first-formed constituent is hornblende, in very much 

 wasted and cavernous crystals, which are in all cases more 

 or less chloritised or replaced by crystalline masses of 

 epidote. The felspars followed next in order of consolida- 

 tion, mostly triclinic, but with a very few individuals of 

 orthoclase. The triclinic felspars are not well bounded by 

 crystalline planes, but are very compound, according to the 

 Albite law, and also in some instances again after the Carlsbad 

 and Pericline laws. The obscuration measurements were not 

 satisfactory, but two in the zone OP — oo Pec were 13° 

 30' and 30° respectively. The triclinic felspars in these 

 rocks seem to be of the Labradorite group. 



