224 Proceedings of Royal Society of Edinburgh. [sess. 
consists of a network of sills, veins, bands, and tongue-like pro- 
trusions of granite, covering a belt of mountainous ground sometimes 
more than a mile broad. The vein-like offshoots do not, as a rule, 
anastomose with one another, but tend to run in a roughly-parallel 
direction, coinciding with the original planes of foliation of the 
schists, although irregular intrusions of granite, having no apparent 
relation to any planes of weakness, are not uncommon. The com- 
plication is such that a line can only with difficulty be drawn 
between schists crowded with granite veins and sill-like bands 
and granite crowded with strips and inclusions of schist of every 
size up to a mile or more in length. ... As we approach the main 
mass of the granite the schists are frequently seen to be so 
impregnated with granitic material that it is impossible in a 
hand-specimen to distinguish the igneous portion from the material 
of sedimentary origin. ... In many places the schists have been 
broken up under the process of injection and a breccia has been 
formed .... consisting of a confused mingling of altered schistose 
fragments in a granitic matrix .... [Some of the] fragments are 
usually crowded with flakes of secondary biotite in more or less, 
parallel layers, and are somewhat suggestive of the origin of certain 
ill-defined patches rich in biotite, occasionally seen in the granite.”’ 
[My own remarks about these inclusions, which form a most 
conspicuous feature in the granites of Ballachulish, were written, 
but not published, before I knew that Mr Kynaston had published 
the note. J. G. G.] 
As contact or thermo-metamorphism of the country rock 
must play an important part in the subsequent processes of 
conversion, especially in the cases where the preliminary changes, 
have taken place under plutonic conditions, a few remarks here 
upon that subject may well be given. In the case of certain 
schists, and of some of the older greywackes, both of which may 
have contained mineral matter of eruptive origin before they were 
affected by thermo-metamorphism, there is usually some advance 
towards the conversion of the rock into hornfels, knotted schist, 
andalusite rock and the like. Radiolarian cherts have been altered 
into granular quartz, almost into quartzite, around the Galloway 
granites, and graptolitic mudstones into graphitic schist. In 
Mull, in Glenco, and in the Lake District, the Green Earths 
