and Igneous Rocks of Ensay. 



93 



In one slice I observed a patch of a colourless or grey fibrous 

 mass. The fibres formed long-bladed crystals ; or it might 

 be said that the fibres were in bundles, and these lay across 

 each other at acute angles, thus forming an approach to a 

 radial aggregate. It has straight obscuration, and very 

 much resembles pyrophyllite. Talc also occurs in divergent 

 scales. 



A little higher up the creek, at 29, there is another out- 

 crop of similar schists, of which I examined the pinite 

 variety both optically and chemically. 



As seen in a hand specimen, the foliations have in them 

 numerous small silvery scales, which yield to the nail, and 

 have the appearance of talc. On a cross fracture the rock 

 has a greenish tint, and at the edges is slightly translucent. 

 The hardness of the rock is from 2* to 3\ 



Under the microscope it proves to be a confused mixture 

 of pinite material, magnesia-mica, alkali-mica, talc, and 

 grains of quartz. The pinite does not differ from that just 

 described. The magnesia-mica is here and there intergrown 

 with alkali-mica, and is much altered to a pale-coloured 

 chlorite. The quartz is in isolated rounded grains. 



Subjoined is the quantitative analysis of this sample : — • 

 No. 6. — Pinite Schist. 



p*o 6 



, , 





•tr. 



Si.O, 



, , 





4572 



AL.O, ... 



. , 





2431 



Fe..O, ... 



, . 





4-72 



Fe.O 



i , 





732 



Ca.0 



, , 





•61 



Mg.O 







4-27 



K,0 







6-47 



Ni.O ... 



. , 





•77 



H 2 



•• 





5-83 





moisture 



100-02 



Hygroscopic 



... 1-33 



Sp. grav. 



.,, 



... 



... 2-78 



Without some more definite knowledge as to the consti- 

 tution of the different minerals in this schist, it would be 

 merely haphazard to attempt to calculate the percentages. 



