File:The Quarterly journal of the Geological Society of London (13204923393).jpg

ROCKS OE THE NORTHERN HIGHLANDS. 383
high-dipping gneiss, with its overlying green grit, is, by powerful
lateral pressure, bent over onto the younger formation. An outlier
of the quartzite forms a thin sheet sloping down the south-eastern
side of Scounan, corresponding to the patch on the Eagle Rock.
These outliers are, of course, the " Upper " Quartzite of authors.
Section across Coniveall. — As the last section shows us how the
Quartzite is brought under the Hebridean, the present one* explains
the mode in which the Ben More Grit is thrown onto the Quartzite
Fig. 6. — Section across Coniveall. (Scale 2 inches to 1 mile.)
S.W. N.B.
Brebag. The Balloch. Coniyeall.
series. High up on Coniveall, as already described, the grit rests hori-
zontally upon the gneiss, Following the former towards the west,
the beds are observed to gradually rise in dip for some distance in
that direction : this fact was independently observed by Mr. Bailey
in 1881. Then they bend right over, and plunge down the precipice
which overhangs the Balloch. I could not descend the cliff far ; but
T was able to trace the beds down for some hundreds of feet with
a glass. The upper part of the curve, however, was easily observed ;
and the rock was hammered over (No. 94, p. 417). Coming down to
the Balloch, to the point vertically under, we find the whole thing-
reversed. Green and red grit, in broken masses, passes under gneiss
dipping E.N.E. at 70°-80°. All the rocks are much disturbed and
crushed; but the main facts are clear. This gneiss is a part of the same
spur-like mass which underlies the grit above. The grit is thus seen
to form a broken fold overthrown to the west, and enclosing a core of
gneiss. On the west side of the pass the Assynt series,- as we have
seen, dips towards the gneiss and grit. We can now more fully
estimate the difficulties of Murchison's statement that the limestone
of the Balloch passes below the " Upper Quartzite" of Ben More.
This and the preceding section are mutually illustrative. The
quartzite in both sections is identical, being continuous in sheets from

• Compare this section with the description of the western scarp in my
  

observations on the structure of the Assynt mountains. The western and