Náttúrufræðingurinn - 1954, Blaðsíða 54

96
NÁTTÚRUFRÆÐINGURINN
SUMMARY:
The Geology of Ieeland II. Some Tertiary Plants From Ieeland
by Jóhannes Áskelsson.
The plantbearing strata here dealt with, are named Brjánslœkiarlög because of
nearness of the gully (Fig. 1) in which tliey creep out to the farm Brjánslækur,
N.W.-Iceland. The section is richly fossiliferous. Though it has not been thorough-
ly examined by any geologist. Collections have been made from the locality, but
none of them has been worked up completely. The only plantdeterminations hitherto
carried out from the Brjánslækur strata are those made by Oswald Heer (Flora
fossilis Arctica, Ziirich, 1886). None of the plants described here are mentioned
by Heer.
1. Picea sp. Pollen grains of conifers are of fairly common occurence in the
Brjánslækur strata. Pollen grains of picea seem to be most abundant. Fig. 2 shows
one of those in proximal view. Seeds, scales and complete cones are common, the
cone depicted here (Fig. 3) corresponds to that of picea.
2. Sassafras sp. Leaves as those here depicted (Figs. 4 and 5) occur rather
abundantly in a certain stratum of the Brjánslækur section. Apparently they are
referable to the genus sassafras. Thus both in shape and nervation they correspond
to the leaves of sassafras. Entire-leaved (Fig. 4) as well as lobed specimens (Fig. 5)
are to be found, but in general the fossil leaves show larger size than do any of
the modern leaves I have had for comparison.
3. Corylus (Cf. americana fossilis Newberry). In the Brjánslækur section there
occur in abundance leaves in various forms which all might be referred to the
genus corylus. The leaf here depicted (Fig. 7) shows resemblance to the leaves of
corylus americana fossilis Newberry (Cf. A. Hollick: The Tertiary Floras Of
Alaska, Pl. 48, Figs 1—3). In pollen slides made from samples of this section pol-
len grains of corylus are frequently met with.
4. Zelkova (Cf. ungeri Kovats). There are some leaves in my collection which
in shape, nervation and serration resemble those of zelcova (C/. ungeri Kovats).
5. Ficus? sp. Some specimens of this leaf are in my collection. Only impres-
sions of the upper halves of the leaves are preserved. On the other hand the
features seen are exellently kept. A heavy midrib, from which five pairs of secon-
daries branch, may be seen. The angles between them and the midrib vary from
50°—60°. The secondaries curve slightly upwards, looping near the margin. Ter-
tiaries percurrent, apex broadly rounded, margin entire, maximum width 7,5 cm.
Should be compared with ficus goshenensis Chaney and Sanborn.