Rit (Vísindafélag Íslendinga) - 01.07.1962, Side 40

40
come from the upper part of 3) or possibly from 5). They
vere not found in situ.
At Heiðarsporðsá the conditions are somewhat complicated
by faults and slight displacements. In the Austurá gully is
found a 40 m thick horizontal sand- and claystone. The upper
part is mainly fine sandstone with cross-bedding; there are
no pebbles. This is probably of eolian origin. There is no ba-
salt cover. The sediment is again seen in another gully far-
ther west.
In the mouth of Grákollugil, on its east side, we have a
kubbaberg of reverse magnetization. From the west a brook
enters the gully in a waterfall. The upper part of the wall
here is the same kubbaberg, uplifted several metres relative
to the occurrence on the east side, and below this we have
a sediment: grey-brown sandstone (1 m) on top and light
green-gray clay (lm) below. This is seen to rest on a lava
of normal magnetization,' so that the sediment forms a boun-
dary between two magnetic groups.
Following now the westerly brook above the waterfall, we
soon find claystone similar to the one below the lava, but
resting on a reverse lava. This clay is covered by brown sand-
stone and a thick reverse lava. Ripplemarks are seen in this
sediment; the total thickness is over 10 m. The sandstone can
be traced for a long distance along the flat water course until
it terminates at two lava flows (fault?). The lower lava is
normal, the upper one reverse and they are separated by
a 1 m layer of sandstone. There are considerable crystal in-
fillings in the upper lava (“sugarstones”). A little below this
place the main sandstone contains leaf impressions.
A little higher (325 m) we have a normal kubbaberg on
the west side of the gully, resting on a 10 m thick sandstone,
while the east wall consists entirely of the sediment. In this,
at 330 m, are many thin seams (6—7 cm and less) of lignite
in light-grey claystone. It seems that the difference of the
two walls of the gully is not due to displacement but that