Rit (Vísindafélag Íslendinga) - 01.06.1923, Blaðsíða 120

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at a greater depth, when the sea-Ievel was up to 40 — 45
m. higher than at present.
The author did not succeed in finding Portlandia arctica
anywhere in the shell-bearing strata investigated by Faxa
flói, or other typical high-arctic species.
The layers containing Sipho togatus at Langisandur (No.
25), and the lower shell strata at Fieynes (No. 26) and OröF
(No. 27) bear the closest resemblance to the Portlandia
strata at Saurbær, but give no such decided indications
of high arctic conditions.
If Portlandia arctica are not brought to light by Further
investigation of other ancient marine strata in Faxaflói, it
may be because this species became extinct here sooner
than in Breiðifjörður, perhaps even before the sea rose
above the present coast-line, late in the Glacial Period. (No.
I in Fig. 8.) At the present time the temperature of the sea
is greater in Faxaflói, and the boreal ingredients of the
mollusc fauna there are more predominant than in Breiði-
fjörður. This may also have been the case in the past.
In Fivamrnsfjörður (a part of Breiðifjörður) some strata
liave been found, abt. 35 m. above sea-level, with some
boreal species (Cyprina islandica, Zirphœa crispata, Littorina
rudis etc.) These strata were deposited while the land was
rising and the coast-Iine stood 40—50 m. higher than at
present. These fauna correspond exactly to the boreo-arctic
mollusc fauna (Zirphœa, Cyprina clc.) in the upper strata
of the marine terraces in Borgarfjörður, which are estimated
to have lived there while the coast line was 40 — 50 m
higher than at the present fime (pp. 82 — 83).