Náttúrufræðingurinn - 1986, Blaðsíða 28

SUMMARY
The Thrælagardur turf wall in
Biskupstungur, South Iceland
by
Bryndís G. Róbertsdóttir
and
Haukur Jóhannesson
Icelandic Museum of Natural History
P.O. Box 5320
125 Reykjavík
This paper describes an ancient turf
wall, Thrælagardur, in Biskupstungur,
South Iceland, where this 6.9 km long turf
wall stretches from the Brúará river in the
west to the Tungufljót river in the east,
fencing off the peninsula between them.
The turf wall is more and less sub-
merged in a boggy landscape and in many
places not visible at all at the surface. On
the other hand sections of the wall were
found in newly dug ditches. The age of the
wall was determined by its position
between two known tephra layers in five
soil sections. The wall is immediately
above the Landnám (Settlement) layer,
which is supposed to have been formed in
a mixed eruption and its age has been
estimated at 850 to 900 A.D. The layer is
easily recognized as the lower part is light
in colour in contrast to the darker upper
part. Other known tephra layers in the
area are Hekla-1104, -1693 and -1766,
and Katla-1721. The layers from
1693 and later overlie the wall where they
can be observed. Hekla—1104 is not found
in the close vicinity of the wall but its
position relative to the Landnám layer sug-
gests that it is younger than the wall.
By using the soil thickening rate
between the Hekla—1104 and Hekla—
1693 layers a date for the Landnám layer
was extrapolated at close to 901—902 A.D.
By the same method the wall was dated to
about 30-40 years later or around 930
A.D.
The Landnáma (Book of Settlement)
mentions a wall named Hagagardur in the
Biskupstungur district. Hagagardur wall is
supposed to be the same as the one pre-
sently named Thrælagardur. The legend of
Hagagardur in Landnáma is also supposed
to be attributable to the writer Ari fródi
(the Learned) Thorgilsson (1068—1148). It
is known that he was brought up and edu-
cated in this district by two men, Hallur
Thorarinsson and Teitur ísleifsson, whose
ancestors settled the Biskupstungur area
around and after 900 A.D. Their common
forefather was Ketilbjörn gamli (the Old)
who was the first settler in the area. He is
believed to have divided his settlement
between his offspring and the Hagagardur
wall (i.e. Thrælagardur) may have served
as a fence or boundary between their
estates.
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