ROCKS OP THE NORTHEEN HIGHLANDS.
391
red felspar bits of -the lowest zone. The
pressure to which the rock has been sub-
jected has flattened the quartz grains ; and
the cleavage and alteration are similar to
those of the Annelidian Quartzite above.
These beds actually lie to the east of the
junction, so that on the strike they pass
under the almost horizontal gneiss. East
of this point the Hebridean rises up and
meets the newer gneiss. It is therefore
evident that this mass of quartzite is a
syncline sharply folded back upon itself,
and closely squeezed in the angle between
the older and younger gneiss.
The curved beds of quartzite on the slope
present a curious phenomenon. The joints
are almost at right angles with the bed-
ding, and are open much wider than the
planes between the beds ; so that at a dis-
tance the quartzite appears nearly hori-
zontal, and the seeming beds are contorted.
This twofold disturbance, the folding-back
of the true beds and the contortion of the
slabs between the joints, points to excessive
lateral pressure acting from the east.
I have said that the Hebridean rises
towards the east, so as to meet the Cale-
donian. This is more clearly seen by de-
scending to the level of the stream. A little
below the reversed fold just described,
and a few feet above the stream, is a
band of conglomerate about 4 inches thick.
The pebbles, which are of quartz in a ma-
trix of small bits of quartz and felspar,
are flattened as if by pressure. This seam
is un distinguishable from a thin band
which forms the base of the quartzite on
Loch Emboli. It dips to the N.W. at 20°,
and it rests immediately upon grey Hebri-
dean gneiss, to the surface of which it is
plastered. The gneiss has its normal strike
to the N."W. The dip of this conglomerate
shows us that the surface of the gneiss
slopes up towards the east, and it confirms
the previous evidence as to the reversed
dip of the quartzite. Following up the
junction, we soon lose the conglomerate un-
der bog ; but the Hebridean can be traced
up the slope at about the same angle, gra-
dually rising to the east of the quartzite to
meet the overhanging Caledonian.
►5'
'S
£.
$5
m