bove Vevey, shows this clearly. It is
quite evident that the lake must formerly have extended further up the
valley, and that it has been filled up by material brought down by the
Rhone, a process which is still continuing.

At the other end of the lake the river rushes out 15 feet deep of "not
flowing, but flying water; not water neither--melted glacier matter, one
should call it; the force of the ice is in it, and the wreathing of the
clouds, the gladness of the sky, and the countenance of time."[51]

[Illustration: VIEW UP THE VALAIS FROM THE LAKE OF GENEVA. _To face page
270._]

In flat countries the habits of rivers are very different. For instance,
in parts of Norfolk there are many small lakes or "broads" in a network
of rivers--the Bure, the Yare, the Ant, the Waveney, etc.--which do not
rush on with the haste of some rivers, or the stately flow of others
which are steadily set to reach the sea, but rather seem like rivers
wandering in the meadows on a holiday. They have often no natural banks,
but are bounded by dense growths of tall grasses, Bulrushes, Reeds, and
Sedges, interspersed with the spires of the purple Loosestrife, Willow
Herb, Hemp Agrimony, and other flowers, while the fields are very low
and protected by dykes, so that the red cattle appear to be browsing
below the level of the water; and as the rivers take most unexpected
turns, the sailing boats often seem (Fig. 34) as if they were in the
middle of the fields.

[Illustration: Fig. 34.--View in the district of the Broads, Norfolk.]

At present these rivers are restrained in their courses by banks; when
left free they are continually changing their beds. Their courses at
first sight seem to follow no rule, but, as it is termed, from a
celebrated river of Asia Minor, to "meander" along without aim or
object, though in fact they follow very definite laws.

Finally, when the river at length reaches the sea, it in many cases
spreads out in the form of a fan, forming a very flat cone or "delta,"
as it is called, from the Greek capital [Greek: Delta], a name first
applied to that of the Nile, and afterwards extended to other rivers.
This is due to the same cause, and resembles, except in size, the
comparatively minute cones of mountain streams.

[Illustration: Fig. 35.]

Fig. 35 represents the delta of the Po, and it will be observed that
Adria, once a great port, and from which the Adriatic was named, is now
more than 20 miles from the sea. P