Rit (Vísindafélag Íslendinga) - 01.07.1962, Blaðsíða 32

32
ance. But as so often in such cases there are no striated hlocks;
only one or two scratched pebhles were found, and the floor
shows no signs of glacial scouring. This is, therefore, most
likely the result of cryoturbation.
This conglomerate rests on a brown sand with river gravel,
mostly smaller than 10 cm in diameter, probably deltaic, al-
though the structure is not clearly seen.
These layers are also seen in the west side of the gully,
falling westwards.
At ahout 400 m the sediments are covered by several thin
layers of grey, fresh, unporphyritic, reversely polarized ba-
salts which correspond to the upper group in Hvammsgil.
The content of rhyolite pebbles is a significant trait. This,
the westerly and even southwesterly direction of the dip of
the delta layers support the impression given by the displace-
ment in the Hvammsgil section that these Young rocks have
not formed in a topography similar to the present one but are
part of a plateau formed prior to the tectonic periods, although
earlier (Einarsson 1958 b) I have assumed that they were
deposited in an old Svartárdalur of the Younger 300 m stage.
Around this part of the Svartárdalur we find a number
of quite flat surfaces at the same level (about 500 m) but
with different rocks in the surface. The Young rocks are thus
not seen in the block above Stafnsrétt. Looking over the sur-
roundings here from the 500 m level one is struck by the
even height of the different blocks into which the area is di-
vided by incision. This is clearly an erosion plane which in
some blocks cuts Young rocks and in others the old ones.
This verifies our results above that considerable planation
has taken place after outpouring, faulting and displacement
of the Young rocks. This planation at the 500 m level it seems
hardly possible to understand, unless it has occurred at a time
prior to the 300 m stages. The Young rocks here may then
correspond to the Young rocks on the west side of Bárðar-
dalur, i.e. to the Young Plateau Basalts. The difficulty of this
view is the fact that we do not find remnants of the Young
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