76 The Sedimentary, Metamorphic, 



in the zone OP — ooPco from 4° to 12°. These felspars 

 are remarkably clear and fresh. 



The two kinds of mica are associated together, one being 

 a brown dichroic magnesia-mica, and the other a colourless 

 alkali-mica. The latter is least in amount, and the former 

 is partly converted into a pale-coloured, chlorite, which is 

 not very dichroic. This mica shows signs of being crushed, 

 so that the folia are in places partly separated from each 

 other. Where it has been completely chloritised innumer- 

 able minute black needles have been formed. 



These two micas and the pinite form foliations separating 

 the compound of quartz and felspar. I defer a more 

 extended description of the pinite until I reach that part 

 from which I obtained those typical examples, of one of 

 which I give a quantitative analysis. 



Adjoining these schists there is a mass of crystalline 

 granular rock, which extends to 2. It is composed of the 

 following minerals in their order of consolidation : — 



(a) Large, simple crystals of felspar, with straight obscu- 

 ration, which are much worn, or cavernous in places, or even 

 broken or crushed, (b) Smaller polysynthetic felspars, w T ith 

 more perfect crystalline forms. These seem to be oligoclase. 

 Some of them are of less size than the others, and all of 

 them are later in consolidation than those before-mentioned. 

 The alteration of all the felspars is micaceous, and in all of 

 them there is a little viridite. (c) Chlorite, which seems to 

 be the alteration product of mica. It is associated with 

 epidote. Here the whole of the mica has been converted. 

 (d) Quartz in rather large grains, being the residual com- 

 ponent. 



At 2 the crystalline-granular rocks are joined by a narrow 

 band of schist, which is followed by a vein of pegmatite, or 

 coarse aplite, beyond which the schists again extend to 3. 



I examined a sample of the narrow band of schist, and 

 found it to be composed of triclinic felspars, mica, pinite, and 

 other alteration products, and quartz. The felspars and 

 quartz, as in the former schist, form foliations separated by 

 the mica, chlorite, and pinite. As before, the obscuration 

 angles of the felspar are low. 



The pegmatite vein is very light-coloured, approaching 

 white, and can be seen microscopically to be composed of 

 large, irregularly-shaped felspar crystals and grains of quartz. 

 The latter have interfered with each other in crystallising, 

 but conform to the outlines of the former. The felspar has, 



