240 B. KOTÖ. 



schistose modification ; transverse sections of the rock have a banded 

 appearance tliroiig-h alternation of feldspar-quartz zones with those im- 

 pregnated with chloritic matters. 



Under the microscope, the coloured com])onents — ^the hornblende 

 and biotite — are seen completely crushed and fashioned into flat 

 spindles, and these resohed into green fibres, but some have cores un- 

 changed. Sometimes the hornl)lende has disappeared entirely, being 

 replaced 1)y masses of epidote and magnetite. The Inotite is bent, and 

 frayed out at the margins. Heterogeneous aggregates, consisting of 

 grains of epidote and clumjis of magnetite, together with chloritic 

 matters, form sinuating zones, contracting and widening at shoi't dis- 

 tances. The feldspar, the most enduring mineral, has escaped the general 

 destruction and granulation, excepting its peripheral portion, nähere the 

 texture is loosened and crushed, producing the cataclastic structure, and 

 there the chloritic fibres have settled, lining the horders of the feldspar. In 

 spite of the soUdilg of quartz, tliis ivas the first that gielded to pressure, 

 and its crushing ahead g seen in tiie (h) imperfectlg schistose granite, is 

 still more evident in the (c) schistose granite. 



Lastly, in the schistose epidote-granite the quartz is totidly reduced 

 to fine dust. Examined by transmitted light, the qu;u*tz appears like a 

 homogeneous, colourless base, encircling and flowing around a s(3me- 

 what porphyritic feldspar. Fine dust is distributed throughout the white 

 mass, and the mass of quartz looks rough, as if it were, the sliced face 

 OÏ a mineral, like olivine. With crossed Niçois the masses resolve 

 themselves into a truly mosaic aggregate, one grain lapping over the 

 other, and flowing along round the deformed edges of the feldspar 

 fragments. The usually vivid colours of polarization, are now faint- 

 blue, and the extinction of light sweeps over from one part to the 

 other 



