370
C. CA.LLAWAY ON THE NEWEE GNEISSIC
Fig. 3. — Section on Poulan-drein. (Scale 3 inches to 1 mile.)
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the right bank the uncertainty is removed. The Brown Flags, in
curved overthrown beds, are succeeded, after an interval of a few
yards occupied by drift and fragments, by the quartzite which we
traced along the scarp, dipping to the S.E. at 5°. This quartzite is
full of the " worm-holes ; " and similar rock can be traced up Poulan-
drein for over a mile, and over the south-eastern slopes of Cnoc-an-
drein to the very summit (over 1500 feet).
Prof. MiaH, F.G.S., Mr. Tiddeman, F.G.S., and Mr. Eccles, F.G.S.,
visited this section under my guidance ; and they all agreed that
there was an overthrown syncline, with a fault beyond ; but they
were not sufficiently familiar with the district to express an
opinion on the age of the quartzite east of the fault.
In this section we see that the Assynt group forms a synclinal
fold thrown back upon itself ; while quartzite, perfectly resembling
the Annelidian Quartzite on the west side of the syncline, appears to
the east in nearly horizontal beds. The natural interpretation of
these facts is, that the underlying quartzite has been brought up
along a line of dislocation and crush, and pushed laterally to the
west, bending back the dolomite and flags. The upthrow cannot
be great, the place of the Annelidian Quarzite being immediately
under the Flags.
Quartzite of Cnoc-an-drein. — I have said that the Annelidian
Quartzite at the Poulan-drein fault can be traced without a break to
the summit of this mountain. Going down from the summit over
the north-western scarps towards Calda Burn, we pass over a de-
scending series, till at the burn we reach the quartzite with red
felspar bits. But this quartzite may be traced down the burn till
it seems to overlie the Dolomite, as in the section described. In
other words, on Calda Burn the Dolomite is conformably (!) succeeded
by beds which are from 100 to 200 feet lower in the quartzite series
than the strata which conformably (!) overlie the Dolomite in Pou-