Jökull - 01.12.1976, Blaðsíða 4

age system on land are the channeis cuttíng
through the ridges and the great lateral channel
running along the Brekkur cliff at the mouths
of the valleys, all following the direction of
slope of the overlying ice sheet, with tlie de-
posits of silt and cobbles, sometimes an unsort-
ed mass called cobble drift, sometimes as deltaic
formations at the valley mouths, associated with
channel ends: these features result from the
englacial drainage. The present valleys formed
the subglacial drainage system and are largely
modified by water action.
THE SURROUNDÍNG AREA
On its southern side, Lundarreykjadalur is
separated from Skorradalur by a rather narrow
ridge, on the western end of which the Hest-
háls channels have been cut. Both ice and water
action can be traced on the top of this ridge.
The head of Lundarreykjadalur and its north-
ern side are cut into a wide area of plateau
(Fig. 1) and the next valley on the northern
side, Flókadalur, is relatively shallow and does
not extend far inland from the coastaí Íowland.
The high Bláskógaheidi section of the plateau,
to the north of Reydarvatn, is covered with
sandy till, with oniy a surface cover of rounded
stones. Examination of this material (no. 2 in
Table I) shows that much of the silt-sized com-
ponent has been removed, possibly by wind and
water action. Ice-scratched basalt surfaces lie
under the material.
At lower altitudes, round the lake Reydar-
vatn, for instance, much of the landscape is
mantled in peat, through which bare rock ridges
show. North of Reydarvatn the hill Skotmanns-
fell has a relatively flat top with sides sloping
at about thirty degrees. However, most of the
hill is made from deposits of large (about 30 cm
diameter) rounded cobbles, which on the top
contrast strongly with the shattered basalt frag-
ments lying round the outcrops of solid rock.
The feature seems to be a basalt hill covered
with thick deposits of water-carried debris.
Further evidence for the work of water occurs
round Reydarvatn, in the form of two shelves,
at 412 m and 405 m, cut horizontally into the
rock of the headland Leirárhöfdi, and the raised
Mynd 1. Efri-Lundarreykjadnlur og nágrenni.
2 JÖKULL 26. /^R