Rit (Vísindafélag Íslendinga) - 01.07.1962, Side 58

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the southern end we see that lavas have an original steep dip
towards south. The Kambur—Böðvarsholtshyrna formation
was probably originally connected with the Helgrindur rocks.
The Helgrindur breccia extends to the west in Rjúpnaborgir,
Miðfell, Steinahlíð, Vallnahjúkur to Fróðárheiði. Here this
formation rests directly on Old rocks, in part rhyolites. The
young formation is very much eroded; the isolated peak
Hestur (672 m), made of horizontal lavas, is a remnant of
a 400 m thick layer which must have covered the Fróðár-
heiði.
Fig. 26. Innribugur.
1 = Old weathered basalts; 2 = fresh conglomerate, about 12 m
thick; its surface is at about 50 m above sea-leevl; 3 = Young lava
of normal magnetization; 4 = tuff; 5 = very thick lava with co-
lumnar and cube jointing; normal magnetization.
From Hestur and Kambsheiði the formation extends to the
north coast on a falling base. At Bugsgil (Innribugur) is the
section shown in Fig. 26.
G. G. Bárðarson mentions three localities in the neighbour-
hood of the village Ólafsvík which clearly belong to the same
horizon as the one shown in our figure. At Innraklif he found
a marine fauna 10—15 m above sea-level, and at Hvalsá and
Fossá 70—80 m above sea-level. The sediments, conglomerate
and fossiliferous clay, rest on a tillite on a striated basalt
floor, and are covered by the younger rocks in turn with a
striated surface.
Bárðarson found only arctic molluscs here (without Yoldia
arctica). Most of them are present Icelandic forms and reach
down to Breiðavík and the Cardium Groenlandicum zone of