88 The Sedimentary, Metamorphic, 



Here, as elsewhere, two kinds of schist can be dis- 

 tinguished, one representing the arenaceous and the other 

 the argillaceous sediments. I found a sample of the former 

 to be composed of irregular foliations of quartz and felspar, 

 mica and pinite. The micaceous foliations are comparatively 

 narrow, and are in places mere partings. The quartzose 

 foliations are made up of grains of quartz, which are in 

 most cases, as seen in the thin slice, much longer than wide. 

 As these grains can be seen in the slice to overlap, it is 

 evident that they represent small discoidal or lenticular 

 masses lying with their flat sides parallel to the foliations. 

 Some of the quartz foliations bifurcate and again combine, 

 enclosing micaceous portions. 



The quartz is full of minute fluid cavities, some of which 

 contain bubbles. Of inclusions there are few, and these are 

 oval colourless to brown microliths and colourless minute 

 rods or prisms, which are probably apatite. 



The felspar grains are few in number, and as they are 

 unstriated I consider them to be orthoclase, which in other 

 respects they resemble. They are kaolinised and contain 

 minute flakes of viridite. These felspar grains only occur 

 in the quartz foliations. 



The micaceous foliations are narrow, but in places widen 

 out to ''■ bulges," and include grains of quartz. Under a 

 high objective the mica is seen to be of a light-brown colour 

 and to be pleochroic. Much of this mica is chloritised. 



The argillaceous variety I found to be composed of 

 alternating foliations of quartz and of mica. This mica is 

 partly in scales and partly in ragged fibrous flakes. There 

 is also some chlorite. 



The quartz grains are angular, and are arranged in a linear 

 manner, thus forming foliations. They contain very numerous 

 fluid cavities, with bubbles, and in parts many colourless 

 minute prisms or needles of apatite, which throughout the 

 slice all lie in, approximately, the same direction, parallel to 

 the foliations. 



This rock resembles the last described, but the proportion 

 between the quartzose and .micaceous materials is reversed. 

 The magnesia-mica in this rock has also a distinctly fibrous 

 structure, and is associated also with alkali-mica, which I did 

 not observe in the other. In places the mica and quartz 

 form a confused aggregate, and not foliations. 



These rocks, it seems to me, have been completely re- 

 crystallised, for I am unable to satisfy myself that any of 



