he Aar, making a
part of Altmann's work upon the Alps.

In 1740, Kapeler, a physician of Lucerne, undertook a journey to the
mountains of the Aar, to visit certain crystal grottos, now well known,
but then recently discovered. He prepared a map of these grottos and
their vicinity, in which they are represented as being situated at some
distance from the extremity of the glacier, the lower end of which is
now considerably beyond them.[50]

But to return to the glacier of the Rhone. We can detect the sequence
and relative age of its ancient moraines, not only by their position
with reference to each other and to the present glacier, but also by
their vegetation. The older ones have a mature vegetation; indeed, some
of the largest trees of the valley stand upon the lower moraines, while
those higher up, nearer the glacier, have only comparatively small
trees, and the more recent ones are almost bare of vegetation. Moreover,
we do not lose the track of the great glacier of the Rhone even when we
have followed its ancient boundaries to the shores of the Lake of
Geneva; for along its northern and southern shores we can follow the
lateral moraines marking the limits of the glacier which once occupied
that crescent-shaped depression now filled by the blue waters of the
lake.

M. de Charpentier was the first geologist who attempted to draw the
outlines of the glacier of the Rhone during its greatest extension, when
it not only filled the basin of the Lake of Geneva, but stretched across
the hilly plain to the north, reached the foot of the Jura, and even
rose to a considerable height along the southern slope of that chain of
mountains. At that time the colossal glacier spread at its extremity
like a fan, extending westward in the direction of Geneva and eastward
towards Soleure.[51] The very minute and extensive investigations of
Professor A. Guyot upon the erratic boulders of Switzerland have not
only confirmed the statements of M. de Charpentier, but even shown that
the northeastern boundary of the ancient glacier of the Rhone was more
extensive than was at first supposed. Other researches upon the ancient
moraines along the shores of the Lake of Geneva, and in other parts of
Switzerland, in which most geologists of the day took an active part,
have made us as fully conversant with the successive outlines and
varying extent of the principal glaciers ranging from the Alpine summits
to the surrounding lowlands as we are with