he last formed, marking its present boundary. Others are visible half a
mile, a mile, and two or three miles beyond, near the villages of
Obergestelen and Muenster. One of the largest and finest of these ancient
moraines of the glacier of the Rhone stands at Viesch, and extends
across the whole valley, while the Rhone, already swollen by many
mountain-torrents, has cut its way through it. Lower down, we meet with
traces of other ancient glaciers, reaching laterally the main glacier,
which occupied the centre of the valley: such was the glacier of Viesch,
when it extended as far down as the village;[49] such was the glacier of
Aletsch, when it added its burden of ice to that coming from the upper
valley; such was the glacier of the Simplon, whose moraines, of less
antiquity, may now be seen by the road-side leading over the Alps to
Italy; such were the two gigantic twin glaciers that drained the
northern slopes of the mountain-colosses around Monte Rosa and
Matterhorn, united at Stalden, and thence, losing their independence,
became simply lateral tributaries of the great glacier of the Rhone;
such were, farther on, the glaciers coming down from all the
side-valleys opening into the Rhone basin; such were the glaciers of the
St. Bernard, and even those of Chamouni, which in those early days
crossed the Tete Noire to unite below Martigny with those that filled
the valley of the Rhone. Thus the outlines of this glacier may be
followed from its present remnant at the summit of the Valais, where the
Rhone now springs forth from the ice, to the very shores of the Lake of
Geneva, where, near the mouth of the river, on both banks of the valley,
the ancient moraines may be traced to this day, thousands of feet above
the level of the water, marking the course the glacier once followed.

It is evident that here the remains of the glacier mark a process of
retrogression; for had these successive walls of loose materials been
deposited in consequence of the advance of the glacier, they would have
been pushed together in one heap at its lower end. That such would have
been the case is not mere inference, but has been determined by direct
observation in other localities. We know, for instance, by historical
record, (see Gruner's "Natural History of the Glaciers of Switzerland,")
that in the seventeenth century a number of successive moraines existed
at Grindelwald, which have since been driven together by the advance of
the glacier, an