the glaciers in their present
circumscription. But no one has done as much as Professor Guyot to add
precision to these investigations. The number of localities, the level
of which he has determined barometrically, with the view of fixing the
ancient levels of all these vanished glaciers, is almost incredible. The
result of all these surveys has been a distinct recognition of not less
than seven gigantic glaciers descending from the northern and western
slopes of the Alps to the adjoining hilly plains of Switzerland and
France. It is most interesting to trace their outlines upon a recent map
of those countries, but it requires that kind of intellectual effort of
the imagination without which the most brilliant results of modern
science remain an unmeaning record to us. Let us, nevertheless, try to
follow.

The glacier of the Rhone, occupying the whole space between the Bernese
and Valesian Alps, filled to overflowing the valley of the Rhone; at
Martigny it was met by a large tributary from Mont Blanc, by the side of
which it advanced into the plain beyond, filling the whole Lake of
Geneva, and covering the beautiful Canton de Vaud and parts of Fribourg,
Neuchatel, Berne, and Soleure, rising to the crest of the Jura, and in
many points penetrating even beyond its outer range.

To the east of this, the largest of all the ancient glaciers of
Switzerland, we find the ancient glacier of the Aar, descending from the
northern slope of the whole range of the Bernese Oberland. The glaciers
that once filled the valley of Hasli, from the Grimsel to Meyringen, and
those that came down from the Wetterhoerner, the Schreckhoerner, the
Finster-Aarhorn, and the Jungfrau, through the valleys of Grindelwald
and Lauterbrunnen, united in a common bed, the bottom of which was the
present basin of the Lakes of Brientz and Thun. These were joined by the
glaciers emptying their burden through the valley of the Kander. To
these combined glaciers the formation of the terminal moraine of Thun
must be ascribed. But before this had been formed, the glacier of the
Aar, in its amplest extension, had also reached the foot of the Jura,
without, however, spreading so widely as the glacier of the Rhone.
Farther to the east Professor Guyot has traced the boundaries of three
other colossal glaciers, one of which derived its chief supplies from
the Alps of Uri, bringing with it all the tributaries which the main
glacier coming down from the St. Gothard rece