Rit (Vísindafélag Íslendinga) - 01.07.1962, Side 44

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hardly any indication of the volcanoes. Dykes or necks are
not found and no structures indicative of a volcano are seen,
although the bombs in Svínafell indicate the neighbourhood
of an explosive vent.
Some general considerations.
In the foregoing we have tried to get a general picture of
the Young rocks in Northem Iceland. Starting with the young
volcanism in Northem Skagafjörður which I have treated in
a separate paper (Einarsson 1959 a) it seems clear enough in
the field that these rocks were deposited on the Lower Pleisto-
cene strandplane cut into old dipping basalts. But to compli-
cate the picture, the west and east coasts of Skagi would seem
most naturallv explained as formed mainly tectonically to-
gether with the more southerly coasts of Skagafiörður and
Húnaflói. A not very happy solution may be suggested on
the basis of observations at Kerlingarbjarg where the lavas
rest on a very thick soft sediment. A flat stretch north of
Kálfshamarsvík is clearly the result of rapid and easy erosion
of this sediment. Supposing, as is probable, a flat peninsula
of older rocks, of similar shape to the present one, existing
before the young volcanics, these would have come to rest
on thicker sediments on both sides of the coastline and so
have fallen an early prey to the erosion. In adclition slight
movement on old fracture lines might have hastened the
development.
Next we come to the Younger 300 m stage. To this should
be referred the lava remnant at the 300 m level in Fnjóska-
dalur. As described in a special paper (Einarsson 1958 b) we
have within valleys of the Skagi mountains and on their west
side Young lavas resting sometimes on river gravel over a
floor of old (dipping) basalts close to the 300 m level. It seem-
ed obvious to me that these lavas flowed at the 300 m stage,
i.e. the Younger 300 m stage, and it still seems to me the only
reasonable interpretation.
But in the apparently corresponding lavas farther south
J