Rit (Vísindafélag Íslendinga) - 01.06.1923, Blaðsíða 107

103
k) Ancient iide marks around Akrafjall (mountain), (pp. 47 - 54).
After the Glacial Period the Akrafjall must have been an
island. A11 around the mountain are old marine formations,
gravel ridges, marine terraces and rock-shelves. They are
easily distinguished and conlinue unbroken up to 40 or
50 m., but in a few places attain a height of about 70 m.
above sea-level (Kúludalsá). Clay strata with shells were
found in 3 places, 1 — 16 m. above sea-level (pp. 50 — 53).
I) Marine deposits at Hvalfjaröarströnd, (pp. 54-5ó).
Distinct and continuous marine formations are found here
up to 40 or 50 m. above sea-level. The highest tide-mark
is 70-80 m. above sea-level. Shells are found in two places,
2-6 m. above sea-level, (p. 55).
3. Survey of the highest tide-marks, (pp. 56—60).
Under the old marine strata in Borgarfjörður glacial-striated
rocks are to be seen in many places on the lowlying ground,
which shows that these strata were formed after the gla-
ciers, at the end of the last glacial period, had left the
lowland. When the glaciers covered the lowland and polished
the rocks as far as the headlands, the sea-level was doubt-
less as low or even lower than it is now. It has since been
raised, or the land has sunk, and at the same time the
climate grew milder so that the glaciers decreased.
On pp. 57 — 58 is a summary of the height of the highest
raised beaches and marine terraces according to the author’s
measurements.
In two places only (Örnólfsdalur and Kroppsmúli) surf
worn gravel, marine terraces and rock-shelves are met with
at a height of 100—115 m. above sea-level.
The author discovered similar tide-marks in many places
70 — 80 m. above sea-level. At that height, however, the ma-
rine deposits around the low-lying ground were not continu-
ous. They were most common in the entrances to valleys