That the valleys were formerly in great part covered by lakes the
soil of which always forms the banks of rivers,--and by seas, which
afterwards, by the persistent wearing of the rivers, cut through the
mountains and the wandering courses of the rivers carried away the
other plains enclosed by the mountains; and the cutting away of the
mountains is evident from the strata in the rocks, which correspond
in their sections as made by the courses of the rivers [Footnote 4:
_Emus_, the Balkan; _Dardania_, now Servia.], The Haemus mountains
which go along Thrace and Dardania and join the Sardonius mountains
which, going on to the westward change their name from Sardus to
Rebi, as they come near Dalmatia; then turning to the West cross
Illyria, now called Sclavonia, changing the name of Rebi to Albanus,
and going on still to the West, they change to Mount Ocra in the
North; and to the South above Istria they are named Caruancas; and
to the West above Italy they join the Adula, where the Danube rises
[8], which stretches to the East and has a course of 1500 miles; its
shortest line is about l000 miles, and the same or about the same is
that branch of the Adula mountains changed as to their name, as
before mentioned. To the North are the Carpathians, closing in the
breadth of the valley of the Danube, which, as I have said extends
eastward, a length of about 1000 miles, and is sometimes 200 and in
some places 300 miles wide; and in the midst flows the Danube, the
principal river of Europe as to size. The said Danube runs through
the middle of Austria and Albania and northwards through Bavaria,
Poland, Hungary, Wallachia and Bosnia and then the Danube or Donau
flows into the Black Sea, which formerly extended almost to Austria
and occupied the plains through which the Danube now courses; and
the evidence of this is in the oysters and cockle shells and
scollops and bones of great fishes which are still to be found in
many places on the sides of those mountains; and this sea was formed
by the filling up of the spurs of the Adula mountains which then
extended to the East joining the spurs of the Taurus which extend to
the West. And near Bithynia the waters of this Black Sea poured into
the Propontis [Marmora] falling into the Aegean Sea, that is the
Mediterranean, where, after a long course, the spurs of the Adula
mountains became separated from those of the Taurus. The Black Sea
sank lower and laid bare the valley of the Danube with the above
named countries, and the whole of Asia Minor beyond the Taurus range
to the North, and the plains from mount Caucasus to the Black Sea to
the West, and the plains of the Don this side--that is to say, at
the foot of the Ural mountains. And thus the Black Sea must have
sunk about 1000 braccia to uncover such vast plains.

[Footnote 8: _Danubio_, in the original _Reno_; evidently a mistake
as we may infer from _come dissi_ l. 10 &c.]

III.

THE COUNTRIES OF THE WESTERN END OF THE MEDITERRANEAN.

The straits of Gibraltar (1083-1085).