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58
I. PHYSICAL GEOGRAPHY.
products of the disintegration of earlier geological periods were swept away and
removed; the bedrock itself was scratched, smoothed and furnished with those
linear glacial strice that we may at the present day often observe on the rocks
exposed to view; the direction of the striæ indicates the course followed by
the ice.
The inland ice gave rise to new deposits, the Glacial Deposits, which were
formed in part during the forward movement of the ice, in part while it was
melting. — In conjunction with an improvement in the climate the inland ice
commenced to melt away and retreat, being finally restricted to the higher,
central parts of the Scandinavian Peninsula. When that was accomplished,
there was till or moraine left behind, consisting of stones and gravel and lying
as an extensive coverlet upon the uneven and undulating bedrock, vthe matter
having been collected and carried along by the ice. The moraine is the most
widely extended of the Quaternary deposits of Sweden. In several places
terminal moraines are to be noticed as well as other ice-margin deposits,
denoting-oscillations or pauses in the retreat of the ice-sheet.
Boulders, not infrequently very large in size, erratic blocks, are found lying
on the ground in numerous localities; they have been carried to the spots where
they now lie by the land ice or by floating icebergs. — Where the material of
which the moraines consist derives from rocks of less hard character, such as
the clay-shales and limestones of the Post-Archæan Systems, it is clayey and
contains carbonate of lime (moraine clay, moraine marl), thereby forming a
fertile soil. The fertile Skåne plains have a soil that in the main consists of
such calciferous moraine-clay.
In close connection with the melting of the ice in Sweden at the end of the
Glacial Epoch there were deposited those remarkable ridges of sand and rolled
gravel that are named åsar. Åsar are to be found in almost all parts of the
country.
Sand and clay were carried off by the glacial streams and deposited in the
sea, in lakes, and in so-called ice-lakes, i. e. lakes formed by the damming up
of the rivers by the retreating ice-sheet.
At the date of the final melting of the inland ice Sweden, Norway, and
Finland (Fenno-Skandia) had a lower level than at the present day, presumably
owing to a depression occasioned by the weight of the ice mass, and consequently
wide areas of what is now land were covered by the sea as the ice retreated. At
that time the North Sea was connected, via Lake Vänern and the province of
Närke, by a broad channel with the Baltic. (Vide p. 56.) In those submerged
regions there was deposited the Låte Glacial Clay, which now lies spread, in many
places beautifully stratified, over the most extensive plains of Sweden and in
other districts too. Remains of shells of the arctic mussel Yoldia arctica have
been found in it, and also skeletons of Greenland seal, great seal, of certain
whale-species and of other arctic marine animals the exact counterparts of
which are now living off the coasts of Spitzbergen and Greenland. — The
laminæ of the låte glacial clay are annual laminæ caused by the yearly
alternation of the seasons; by counting up their number in the various regions,
from South to North, throughout the parts of the country where deposits of the
clay are found, it is possible to fix the length of time that was absorbed in
their formation.
When the submerged land again began to rise above the Sea, the Närke
Channel became shallower and shallower. Thus the Baltic was early shut off
from connection with the North Sea and transformed into a fresh-water lake,
named, after the small fresh-water mollusc Ancylus fluviatilis living in it, the
Ancylus Lake. By that date the climate had so much improved that most of the
present flora and fauna of Fenno-Skandia made their appearance. Upon the
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