Rit (Vísindafélag Íslendinga) - 01.07.1962, Page 24

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transport. There is no scoured floor, but just a gradual change
from the underlying brown gravel. Again we have fluviatile
gravel, 8—-10 m thick, covered hy an extremely coarse layer.
It might seem to be a crumbled lava of coarse columnar
structure, yet the hlocks are somewhat wom. These layers
have all a northward dip.
In all conglomerates there occur some pehbles of rhyolite.
The hardness is such that fractures often cut straight across
the basalt blocks. In Stapar the sediments reach down to

’xs s
Fig. 11. Left end of section in Fig. 10.
s = sand; g = gravel.
about 130 m above sea level.
The rhyolite pebbles, the hardness, the brown colour, and
the moraine-like conglomerate indicate the relationship with
the sediments in Hlíðarfjall, and the lack of material derived
from the Young kubbaberg lavas seems to prove that we
are dealing with a sediment older than that volcanic period,
i.e. the sediments separating the old basalts from the Young
rocks. The low position also indicates that we cannot refer
the sediments to a 300 m base level.
When we consider these sediments and the dipping Young
rocks at the Upper Jökulsá (p. 26) it seems most likely that
they are of pre-tectonic age. They have been in a sheltered
downthrown position, possibly below sea level, when the
great post-tectonic planation took place.
5. Section of Fossá (Lambárfell). The Young rocks form
a thin cover southwards from Sauðafell (section 2). Where
detectable the magnetization is reverse. The uppermost part
of this reverse group and a trace of the covering normal
group is finally found at Lambárfell, where the Fossá has
eroded a canyon. The following section is found here, Fig. 12.