106 ’ Messrs. Hicks and Davies— 
as characteristic of the so-called newer or eastern metamorphic 
groups. Their thickness here is very considerable, and they doubtless 
therefore are to be found in other western areas. That they belong 
to the Pre-Cambrian rocks there can be no doubt whatever, as 
evidenced by the vertical position of the beds, their strike, and intimate 
association generally with the typical gneisses of the district. 
Moreover, the Cambrian rocks rest horizontally upon their upturned 
edges, and may be seen in this position not only along the shore, 
but high up in the mountains. That they were also in their present 
altered position before the Cambrian rocks were deposited upon 
them is clear from the abundance of fragments found in the con- 
glomerates at the base of those rocks. 
A more quartzose variety found in association with these dark 
schists is described in the subjoined Note 1 by Mr. Davies; and a 
light red highly felspathic compact gneiss found interstratifying the 
same schists rather high up on the same face of the mountain look- 
ing over Gaerloch, and very conspicuous amongst the darker schists 
by its colour, is described in Note 2. 
Hornblende is usually absent in the quartzose gneisses here, as 
well indeed as in the majority of those to the north and south of 
this immediate area. Its place seems to be taken up almost entirely 
by black mica, and in this these gneisses differ markedly from those 
usually described as characteristic of other western areas and of the 
Hebrides. 
This is the more remarkable also, as it will be seen that horn- 
blende rocks and schists are plentiful in many parts of the district 
to the North and South. The felspar is also of a lighter colour on 
the whole, than in the Lewisian gneisses, being usually white or 
pale pink. 
[ Norse 1.—A very micaceous schistose rock, resembling a fine-grained 
mica quartzite, or a mica-schist. A microscopic section shows quartz 
in small grains, crystalline, but not intimately so, the grains being 
usually isolated. Nests of quartz are not infrequent, around which 
the mica curves. The orthoclase felspar being much altered and 
principally filling the spaces between the quartz grains is not easily 
recognizable; but the plagioclase is in a fresher condition. Occa- 
sionally large crystals of orthoclase occur, in which are inclosed 
numerous quartz grains. The predominant mica is biotite, though a 
monochromatic mica is frequent, both of which, besides their general 
parallel directions, are frequently developed at all angles to the 
plane of foliation. Small garnets and exceedingly minute sphene are 
frequently to be observed.—T.D. | 
[Norz 2.—Macroscopically this is a pale pinkish red gneissic 
rock, apparently consisting of felspar. and quartz only, and is. very 
fine-grained. Microscopically it is found to be made up of an 
intimately crystalline mass of felspar and quartz in fine grains. 
The quartz appears also as individual grains inclosed in the felspar 
crystals. But this constituent here takes the position of the mica 
in the preceding rock. To its development into more or less 
continuous wavy bands, bulging out here and there by the growth 
