Rit (Vísindafélag Íslendinga) - 01.07.1962, Síða 126

124
polished and striated surface of another moraine, (1), of a
slightly different colour. This moraine is stratified and the
surface on which (2) rests cuts discordantly this stratifica-
tion. Basalt cobbles in (1) have been worn evenly with the
surrounding matrix which must have been hard at that time.
Later the two hard moraines were eroded and cut by the 35°
steep slope s-s. Then this slope was polished and striated by
a glacier running along it. After this surface had been co-
vered by a 30 cm thick layer of brown sand it was finally
covered partly by a mass of primary tuff, consisting of pu-
mice and fine scoriae. This mass has been much eroded and
it is covered in part by loose glacial debris and must there-
fore have been overridden by a glacier.
All these glacial vestiges are not only younger than the
dolerites but must be considered as younger than the tectonic
phase. The moraines have been sheltered in a groove along
a tectonic ridge. Further, the striae have in all cases the south-
westerly direction suggesting the existence of and guidance
by the Vatnshlíð slope.
A correlation of these four glaciations with the main events
of the Pleistocene is naturally very difficult. The locality is
not far from the edge of the later Pleistocene glaciations at
any rate, and one must therefore think of interstadials as well
as interglacials between the glaciations of the place. Never-
theless, between the second and third glaciations there is
such a large erosional gap that an interglacial is suggested.
This might also apply to the interval between the third and
fourth glaciations. It seems most likely that,the dolerites and
the following tectonic phase fall back into the Mindel-Riss
interglacial at least, a conclusion bome out by various other
facts which we shall consider below.
Sveifluháls. Connected with the uplift east of Vatnshlíð
there was probably a subsidence in the area of the present
lake Iíleifarvatn comprising also Sveifluháls-Undirhliðar and
Núpshlíðarháls. In this basin was formed by later volcanism
a layer, at least 250 m thick, of mostly rather fine stratified