ard plain from the pinnacled roof of Milan Cathedral,
or who has passed by rail through that monotonous level of poplars and
vines between Verona and Venice, knows well what a mud flat due to
inundation and gradual silting up of a valley looks like. What I want
to do now is to inquire into its origin, and to follow up in fancy the
same process, still in action, till it has filled the Adriatic from end
to end with one great cultivable lowland.

Once upon a time (I like to be at least as precise as a fairy tale in
the matter of dates) there was no Lombardy. And that time was not,
geologically speaking, so very remote; for the whole valley of the Po,
from Turin to the sea, consists entirely of alluvial deposits--or, in
other words, of Alpine mud--which has all accumulated where it now lies
at a fairly recent period. We know it is recent, because no part of
Italy has ever been submerged since it began to gather there. To put it
more definitely, the entire mass has almost certainly been laid down
since the first appearance of man on our earth: the earliest human
beings who reached the Alps or the Apennines--black savages clad in
skins of extinct wild beasts--must have looked down from their slopes,
with shaded eyes, not on a level plain such as we see to-day, but on a
great arm of the sea which stretched like a gulf far up towards the
base of the hills about Turin and Rivoli. Of this ancient sea the
Adriatic forms the still unsilted portion. In other words, the great
gulf which now stops short at Trieste and Venice once washed the foot
of the Alps and the Apennines to the Superga at Turin, covering the
sites of Padua, Ferrara, Bologna, Ravenna, Mantua, Cremona, Modena,
Parma, Piacenza, Pavia, Milan, and Novara. The industrious reader who
gets out his Baedeker and looks up the shaded map of North Italy which
forms its frontispiece will be rewarded for his pains by a better
comprehension of the district thus demarcated. The idle must be content
to take my word for what follows. I pledge them my honour that I'll do
my best not to deceive their trustful innocence.

It may sound at first hearing a strange thing to say so, but the whole
of that vast gulf, from Turin to Venice, has been entirely filled up
within the human period by the mud sheet brought down by mountain
torrents from the Alps and the Apennines.

A parallel elsewhere will make this easier of belief. You have looked
down, no doubt, from the garden of the hotel at G