Rit (Vísindafélag Íslendinga) - 01.07.1962, Page 49

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sives. Valleys like the Stóri-Langidalur are well graded to
the strandplane.
Along the inner part of Hvammsfjörður the plane is much
less preserved, quite possibly due to glacial erosion. The depth
of this inner part is maximally 50 m.
A large part of the Breiðafjörður is very shallow and there
are innumerable islands formed of old basalts, often dipping
considerably. The height is mostly below 20 m, rising maxi-
mally to 41 m (Elliðaey). It seems likely that the extensive
plane at the mouth of Hvammsfjörður is to a great part due
to river erosion. The valley which has now become the
Hvammsfjörður, as well as Galtardalur, Flekkudalur, and
the valley of the Skorravikurá have been graded to the base
level of the strandplane and, coalescing at the mouth of the
present Hvammsfjörður, have formed a wide plain. Similarly
the island plane of Breiðafjörður need not be referred exclu-
sively to marine erosion. The numerous valleys of the north
coast would have coalesced and formed a broad plain, or
there were left between them narrow ridges which marine
erosion could master. Marine erosion of the order of 2—3 km
is indicated at many places, as we have seen, so it could ad-
vance far on a much dissected coast.
On the south coast of Breiðafjörður the strandplane extends
westwards beyond Thórsnes. It is hidden under “dolerite”
(Thoroddsen) between Grishólsá and Berserkjahraun. At the
bridge over Gríshólsá is an outcrop of a fresh pillow- and
columnar-lava of normal magnetization. The strandplane sur-
rounds Bjarnarhafnarfjall, which in Hestadalur carries a
beautiful remnant of an older topography, presumably of
the Younger 300 m stage. Further the plane surrounds the
peninsula between Kolgrafarfjörður and Grundarfjörður, on
which two isolated mountains (Eyrarfjall, Setbergsklakkur)
are left. The landscape on this peninsula may well give an
idea of the type of topography existing in the northwestern
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