Rit (Vísindafélag Íslendinga) - 01.07.1962, Page 80

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are no such elements which would enable an undouhted identi-
fication of the tuff-breccia formation in Súlur, Gagnheiði, and
Ármannsfell.
A remarkable section of the Ármannsfell rocks is seen in
Stórkonugil, on the east side, Fig. 38. This gully existed be-
fore the last glaciation, its lower part has been “clothed”
with a stratified moraine. At the foot of the main slope of
the mountain, at the site of the inferred fault h, is a mound
of primary breccia, probably the result of a small eruption.
Over the steep slope of the mound flowed a lava that was
much disintegrated before being covered by a moraine.
3
Fig. 38. Section of Ármannsfell in Stórkonugil.
d = dykes; further explanation in the text.
The block g-h consists of eastward-dipping layers of breccia.
This is probably not a primary volcanic formation; bombs
or bomb fragments are not apparent. It consists essentially
of very coarse basalt debris and is most naturally interpreted
as scree. A lava and primary breccia is on top. On the west
side of the fault g the same secondary breccia is seen, with
greater dip, and it is here mixed with and overrun by simi-
larly dipping lavas, which clearly have flowed down a slope.
On an erosion surface, cutting these lavas, rests the lapilli
tuff described above as resting on the summit of the moun-
tain. It is clear that at the east side of Ármannsfell we are
concemed with an original slope advancing eastward by the
addition of material from above. In the beginning the added
material was all in a fragmental state, hasalt debris cleared