File:The Quarterly journal of the Geological Society of London (12981431874).jpg

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MTJECHISOX NORTHEEN HIGHLANDS, ETC.
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VOL. XV. PART I.
dently referable to marine plants or
fucoids * ; but nowhere has anyone —
not even the keen-eyed Peach — col-
lected a form which can be referred to
terrestrial vegetation. The exact po-
sition of the SerpuUtes MaccuUochii
and the Fucoids, as thus given, is to be
traced over a considerable area, both in
the environs of Assynt and ia those of
Loch Eribol.
It is to be observed that the siliceous
courses in which anneKdes occur, are
not to be considered a porous granular
quartz, as stated by Macculloch, but
as a hard compact rock which simply
becomes porous upon weathering, when
the fossils are best exposed.
Instructive sections in ascending
order may be made, either from the
Kyles of Strome or from Loch Inver,
in Sutherland. The former, however,
is by far the most satisfactory, because, *
by slight deviations only from the road,
the passing traveller may satisfy him-
self of the truth of all the data of su-
perposition. Quitting the rugged bosses
of gneiss at the Perry, and ascending
to the summit-level of the road, he
soon meets with layers of the chocolate -
coloured Cambrian sandstone, which,
sweeping down to the road from the
lofty precipices of Queenaig, dip to the
W.N'.W. at the sKght angle of 5° or 6°;
so nearly do the beds of that very an^-
cient rock approach to horizontality.
Here there is no ambiguity ; for the
chocolate- coloured Cambrian rock is
clearly superposed by sheets of the
compact quartz -rock, which dip from
20° to 25° to the S.E. In short, no
unconformity can be more striking;
and the quartz-rock, at the summit-
level of the road, rests on the shoulders

• The fucoid-bed and its associates were
  

traced by Mr. Peach from Ledbeg near Loch
Awe, by Stronchrubie, Inchnadampf, Assynt,
Bridge of Skiag, and thence towards Kyle
Scow, and at two of these places Prof. Nicol
and myself had previously detected it. Mr.
Peach observed them in precisely the same
position on the eastern shores of Loch Eribol.