Rit (Vísindafélag Íslendinga) - 01.07.1962, Side 29

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In the next 20 m brown sandstone peeps out through scree.
At the top it is of grey colour and fine grain. The sandstone
is covered by a further 20 m of conglomerate. At 395 m this
is covered by a primary volcanic breccia of reverse magne-
tization. Farther east, however, there is a 100 m wide and
20 deep erosional groove in the conglomerate, filled with
several thin lavas of normal magnetization. Between these
lavas and the reverse breccia is a 1—2 m thick sediment,
mainly crossbedded fine eolian sand, but at the top is grey
sand with scattered pebbles. At places we find also a very
coarse conglomerate with a sparse matrix. Here, then, we
have an interval separating two magnetic periods.
Farther east is a displacement which throws the Young
rocks 40—50 m down on the east side. The displacement is
marked partly in the surface but mostly it has been wiped
out by erosion.
The lavas of the lower Young magnetic group rest on river
gravel over weathered sandstone and the groove was probably
a river bed.
Fig. 15. Ilvamrnsgil.
1 and 3 = interglacial eolian sand; 2 = covering moraine.
The south wall of the Hvammsgil has a thick cover of late glacial
sediments under which the hasalts are not seen. The sediments are mostly
of morainic nature but at the main sharp hend of the brook an inter-
glacial windborne sand is seen under the moraine, Fig. 15. The fine sand
of a peculiar beautiful blue-grey colour with only a few scattered pebbles
in the middle of the section, extends from the river hed (lower contact
not seen) some 30 m up and is there covered by the moraine. The sand,
which is very little consolidated, was deposited into the gully before the
last advancement of the ice over this region. That the brook did not pre-
vent this deposition probably indicates a dry climate.