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Upon the Silurian slate and limestone of the Kristiania
district follows a series of sandstone, mostly reddish, not
separately marked on the map. Only some very few and ill preserved
fossils have been found therein, probably this sandstone is Devonian,
corresponding to the «Old Red» of the British Islands. The rest
of the supposed Devonian of Norway forms four areas on the
west coast to the north of Bergen. Fossils are absent here.
If we draw a line from the southernmost point of Norway,
Lindesnes, to the North Cape, such a line divides, in a broad
way, the Scandinavian peninsula into two parts, which are very
different in so far as the area to the east has not been subject
to mountain-making compression to any considerable extent since
the beginning of the Cambrian period. We may call it «The
Scandinavian-Finnish plateau». It is, upon the whole, a flat and
low but uneven land, in which the Gulf of Bothnia occupies a
shallow basin. The south-eastern part of Southern Norway belongs
to this plateau.
To the west of the above-mentioned line we have «The
Western Scandinavian Mountain Region», where the earth’s crust has
greatly been contorted since the Silurian period. The
Cambro-Silurian rocks have been altered by this folding process, and the
underlying Archaean has been squeezed into them and has also
been altered.
The consequence is, that in many cases it is difficult to
separate the altered Cambro-Silurian from the Pre-Cambrian rocks.
An additional difficulty is, that not folding alone but also
overthrusts of enormous extent seem to have played a role in the
construction of the mountain region. The highest part of the
Scandinavian peninsula is the district to the east of the inner
part of the Sognefjord, the Jotun mountains. Masses of gabbro,
which has existed before the folding process and has been acted
upon by it, are here predominant and constitute the rock of the
highest peaks.
While the Cambro-Silurian rocks of the Kristiania district are
chiefly shales and limestones and in the Sparagmite area chiefly
sandstones, in the Trondhjem area which comprises the country
to the south and east of the Trondhjemsfjord, the Cambro-Silurian
has quite another aspect, as great volcanic activity characterised
the Cambro-Silurian period in these parts. Deposits of great
thickness occuring here were probably originally composed of basic
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