and Igneous Rocks of Ensay. 89 



the quartz grains are of clastic origin; j 7 et I can feel no 

 doubt, after the extended examination -which I have now 

 made of the Ensay Rocks, that these schists were once sedi- 

 ments. 



These two examples are from 22, and represent the schis- 

 tose types. It yet remains to examine the massive variety. 

 For this purpose I prepared slices of two samples — one 

 collected at 23, and the other at 24. 



The former is a compound of angular grains of quartz, 

 brown mica, and micaceous alteration-products, in about 

 equal amounts. I cannot say what the micaceous aggregates 

 may represent, unless felspars, of which there is no trace in 

 the slice. The mica is brown and pleochroic, and it is partly 

 converted into a rather pale and not very dichroic chlorite, 

 with the elimination of iron, in needle-like crystals. "When 

 examined by a high objective I find that the micaceous aggre- 

 gates are full of minute stout, straight, or curved micro- 

 liths. I might call them stout fibres, similar to those which 

 I have spoken of finding in the pinite. In places these are 

 arranged linearly, or in linear groups, so that they produce a 

 fibrous effect. 



The quartz grains are of two kinds — one which contains 

 very numerous colourless hair-like microliths, the other 

 without them. Where the microliths are absent there seem 

 to be many more fluid cavities. This may, perhaps, indicate 

 two generations of quartz grains. 



The second sample is from the massive bedded schists at 

 24. Under the microscope it is seen to be composed of 

 small masses, having aggregate polarisation, such as occur 

 also in the last-described rock. There are also spaces filled 

 by pinite ; and a rudely foliated structure is produced by 

 the association together of these with a little brown magnesia- 

 mica, colourless alkali-mica, and divergent fan-shaped tufts 

 of talc. 



The quartz grains are numerous, and generally scattered 

 irregularly in the mass, but also more or less lying between 

 the foliations. 



There are no felspars to be seen in this sample, but it may 

 be that they have been wholly converted into the micaceous 

 aggregates of the foliations. 



At the spot marked 25 upon the plan there is' a strong 

 dyke having a meridianal strike. It probably extends much 

 further to the north, for there is an outcrop of a similar but 

 somewhat altered dyke close to the Ensay homestead, and, as it 



