The Botany of Iceland - 01.12.1914, Blaðsíða 57

PHYSICAL GEOGRAPHY
241
The surface of the interior plateau, with the exception of the
glacier-covered areas, consists of deserts of stones, lava, gravel and
blown sand. Where the underlying rock is basalt, the surface of
the plateau is usually strewn with angular blocks of basalt, often
in irregular heaps. Occasionally ridges are found, covered with
gravel and hlocks of glacial origin, but blocks split by frost are
decidedly the xnore frequent upon these ridges. Ön the plateaus
above the fjord districts of East Iceland, extensive areas are covered
with angular blocks of basalt, but usually this layer of loose blocks
is relatively thin. Similar conditions are met with in the north-
vvestern peninsula and on the mountains of North Iceland; but in
the interior of the country glacial materials and the more recent
formations preponderate. In that part, therefore, the greater part
of 4he area consists of ice-striated ridges of dolerite, post-Glacial
lavas, old bottom moraines and blown sand. Ice-striated streams
ol' old dolerite-lava occupy vast areas in the interior. North of the
great Jökulls the dolei'ite lavas may be traced conlinuously from
Arnarvatn in the west to Snæfell in the east. Here and there the
dolerite is covered with recent lava, and the closer the Jökulls are
approached the thicker becomes the surface-layer of glacial gravel.
As already mentioned, these monotonous, bluish-grey, stony deserts
present an extremely desolate appearance. The only points upon
which the eye can linger are scattered snow'-drifts and large erratic
blocks Ij'ing scattered upon the ridges. The landscape has undoubtedly
remained for centuries unaltered in appearance; it must have looked
as it does now, immediately after the snow'-fields of the Ice Age
had retired. There is no sign of life, and deep silence reigns over
the land. The dolerite ridges, as has been already said, are covered
W'ith blocks rent by frost lietween which ice-striated domes protrude
here and there. AIl the upper faces of the stones are dully polished
and seamed by wind-abrasion. For days the traveller may see
nothing else but gravel and ridges of rocks in endless succession
like waves upon the sea; while as regards plants, only at intervals
of 10 to 20 metres may a few stunted specimens of Armeria mari-
tima, Salix herbacea and Cerastium alpinum be met wilh; the first-
mentioned plant occurs most frequentlj'. Here and there partially
dried-up water courses and river-beds are found which are filled
during the thaws of spring; and pools and small lakes are also
occasionally met with hidden awray in the low-lying ground be-
tween the ridges. In the immediate neighhourhood of the Jökulls,