Much of the Highland Controversy rested on the nature of the Moine. They are an enigmatic group of rocks that
form much of the geology of the northern Highlands of Scotland. A cursory glance suggests that they are simple,
parallel-bedded sediments. But this can be misleading. It
is true that the Moine started off as a series of sedimentary rocks, chiefly sandstones and shales. Careful
searching (and a lot of luck) can reveal outcrops with cross-bedding.
However,
recognising the sedimentary origin can take more faith - as seen from these highly stretched out pebbles in a
conglomeratic part of the Moine.
Within
the Moine outcrop there are slices of banded gneisses with a distinctly Lewisian-like appearance. These probably
constitute an early metamorphic basement on top of which the Moine sediments were deposited.
However,
the Moine has been strongly deformed, into tight folds, and features within the rock can be greatly streaked out, 
like
these veins. So much of the apparently simple banding is an artefact of intense shearing. This was one of Lapworth's
critical contributions to resolving the Highlands Controversy.
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