Rit (Vísindafélag Íslendinga) - 01.06.1923, Blaðsíða 111

107
eral observations are here recorded of various places on
the south coast of Faxaflói and in Árnessýsla, which bear
out this theory.
II cannot be determined with any certainty how quickly
these changes are taking place, or to what extent they have
taken place within the range of history. According to the
information given in those of our old sagas which can be
relied upon, it seems that the alteration in the sea-level
during the last millenium (since lceland was pöpulated)
would hardly exceed 1 m. and is perhaps rather less.
The line of demarcation between these opposite process-
es of change in the coast-line seems to lie through Snæ-
fellsnes or the southern limit of Breiðafjörður, where the
most northerly volcanic belt (where eruplions took place
after the Glacier Age) lies, to the west of the highlands.
The country to the south, which seems to be subsiding,
is intersected by many volcanic fissures, from which erup-
tions have taken place as recently as our own times. Earth-
quakes are also very common in these districts. Possibly the
tracts between the fissures are gradually subsiding, and
some of the earthquakes may be caused by these subsid-
ences.
We have not yet obtained any information with regard
to changes in the coast line in recent times on the East
Coast of Iceland or on the North Coast to the east of
Húnaflói.
Fig. 8. shows roughly the changes that have taken place
in the sea-board at Faxaflói from the latest part of the
Glacial Period up to the present day, as far as the ob-
servations already made seem to indicate.
The horizontal line (0) denotes the present sea-level and
the dotted line 1—6 shows the rise and fall of the sea-
level at different times after the Ice Age.
1. The later Glacial subsidence of the land or the rise
of the sea-level up to the upper marine boundary 80 — 100
m. above the present sea-Ievel, at the close of the Ice Age.