Rit (Vísindafélag Íslendinga) - 01.07.1962, Page 33

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rocks on the neighbouring high mountains. The answer to
this objection would be erosion, such as was evidenced by
the lack of the Young rocks on some of the 500 m blocks at
Svartárdalur. The Young rocks would remain in individual
blocks in this area entirely on account of relatively low and
sheltered position.
2. Blöndudalur. The Young rocks form a cap of the ridge
between Blöndudalur and Sléttárdalur, lying horizontally on
an even surface of steeply (up to 30°) westwards dipping
older basalts. At Gilsá these old rocks are exposed. (This
60—70 m deep gorge is older than postglacial; it has been
filled with a moraine which is still left as large patches, even
reaching the bottom of the gully. A similar observation I
made in a gorge at the head of Svartárdalur in Skagafjörður;
cf. also Hvammsgil.) At 340 m one meets the Young rocks in
the form of a normally magnetized volcanic breccia.
At the northern end of the spur, above the farm Langa-
mýri the Young rocks are again partly exposed. At 265 m
there is fresh kubbaberg of reverse magnetization.
305 m, top of next lava, also reverse kubbaberg.
350 — kubbaberg of normal magnetization.
385 — kubbaberg of normal magnetization, resting on brown
primary breccia which in part is globular basalt.
This is covered hy coarse river gravel on which rests
the top-layer at 395 m. It is a lava of reverse magne-
tization, of columnar jointing below and kubbaberg
above.
The Young rocks here consist, then, of 3 magnetic groups,
as mentioned earlier. The two upper ones are especially fresh,
the lowest is somewhat more weathered but infillings are not
seen. The young lava of normal magnetization, capping Sól-
heimaháls at 300 m is assumed to belong to the middle group.
Ahout 15 km south of Langamýri Blanda emerges from a
deep canyon, cut in the Young rocks. Here, 2 km south of
Vallgil, the river bed lies at 250 m and in the 140 m high
wall above we have 10 reverse lavas and 3 sediment layers
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