Rit (Vísindafélag Íslendinga) - 01.07.1962, Qupperneq 27

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to find it in the southern Eyjaf]örður area. From Urðarvötn
to Jökulsá the surface is covered by a thick mantle of weather-
ing dehris and the rock is seldom seen. In this mantle pieces
of brown sediments, i.e. sandstone and mudstone are com-
mon. In some cases they can he traced to horizons in the
plateau and in other cases their distribution indicates the
disintegration of a plateau layer. This weathering mantle is
in my opinion therefore not in essence a Pleistocene moraine
but a long-term weathering mantle from the plateau, little
influenced by Pleistocene ice cover. (Cf. also an old hard
cover of debris at the head of Eyjafjörður, Einarsson 1959 b).
It can hardly be doubted that the Young rocks at Jökul-
dalur and Fossá belong to the same group, and thus we must
face the possibility that also the outliers in sections 1—4 are
of pre-tectonic age, i.e. older than the Older 300 m valley
generation.
Húnavatnssýsla.
1. Svartárdalur. Exposures of the Young rocks are found
on the east side of the Svartá along the sharp bend of the
valley between the farms Skottastaðir and Hvammur, and
in the north side of the gulley Hvammsgil. The section in
Hvammsgil is shown in Fig. 14.
The surface of the steeply dipping old basalts is seen at A
and B. At A this surface lies at 360 m. A groove in it carries
first a thin layer of river gravel and hard, brown-pink sand-
stone. The pebbles consist of old basalt only. On this gravel
rests a block 2 m high and 6 m long of hard brown sandstone
in which the stratification is nearly vertical. The block is
clearly transported; possibly it has fallen from an escarp-
ment. The block is covered by a nearly horizontal greyish
brown sandstone, which also leans against and covers a pin-
nacle of basalt which projects from the eroded basalt floor.
The floor was not visibly glacially eroded; it was probably
eroded by the wind, and the sandstone is probably of eolian
origin.