ived right and left, in its
course through the valley of the Reuss and the basins of the Lakes of
Lucerne and Zug. The second, born in the Canton of Glaris, followed
mainly the present course of the Linth and the basin of the Lake of
Zurich. Professor Escher von der Linth has shown that the lovely city of
Zurich is built upon a moraine, like Berne. The imagination shrinks from
the thought that all the beautiful scenery of those countries should
once have been hidden under masses of ice, like those now covering
Greenland. The easternmost ancient glacier of Switzerland is that of the
Rhine, arising from all the valleys from which now descend the many
tributaries of that stream, spreading over the northeastern Cantons,
filling the Lake of Constance, and terminating at the foot of the
Suabian Alp. Next to the glacier of the Rhone, this was once the largest
of those descending from the range of the Alps.

West of Mont Blanc Professor Guyot has traced the boundaries of two
other distinct ancient glaciers; one of which, the glacier of the Arve,
followed chiefly the course of the Arve, and, though discharging the icy
accumulations from the western slope of Mont Blanc, was, as it were,
only a lateral affluent of the great glacier of the Rhone. The other,
the glacier of the Isere, occupied, to the south and west of the
preceding, the large triangular space intervening between the Alps and
the Jura, in that part of Savoy where the two mountain-chains converge
and become united.

It would lead me too far, were I to describe also the course of the
great ancient glaciers which descended from the southern slopes of the
Alps into the plain of Northern Italy. Moreover, these boundaries are
not yet ascertained with the same degree of accuracy as those of the
northern and western slopes; though very accurate descriptions of some
of them have been published, with illustrations on a large scale, by MM.
Martins and Gastaldi, and of others by Professor Ramsey. I have myself
examined only the upper part of that of the valley of Aosta.

The evidence concerning the ancient glaciers of the Alps, especially
within the limits of Switzerland, is already so full that it affords
ample means for a comprehensive general view of the subject. It is
frequently the case, that, when a stretch of time or space lies between
us and a matter we have once studied more closely, it presents itself to
us as a whole more vividly than when our nearness to it forced