THE CRAU.
The Basin of Berre—A neglected harbour—The diluvium—Formation of the Crau—The two Craus—Canal of Craponne—Climate of the Crau—The Bise and Mistral—Force of the wind—Cypresses—A vision of kobolds.
On leaving Marseilles by train for Arles, the line cuts through the
limestone ridge of the Estaque, and the traveller passes from the basin of
Marseilles into the much more extensive basin of Berre, surrounded by hills
on all sides, a wide bowl like a volcanic crater, with the great inland
salt lake of the Etang de Berre occupying its depths. This is a great
natural harbour, seven times the size of the port of Toulon, and varying in
depth from 28 to 32 feet; it is perfectly sheltered from every wind, and
entire fleets might anchor there in security, not only out of reach, but
out of sight of an enemy, for the chain of l'Estaque intervenes between it
and the sea. It would seem as though Nature herself had designed Berre as a
safe harbour for the merchant vessels that visit the south coast of France. It is almost inconceivable how this sheet of water, communicating with the sea by the channel of Martignes, can have been neglected; how it is that its still blue waters are not crowded with ships, and its smiling shores not studded with a chain of industrial and populous towns. "The neglect of this little inland sea as a port of refuge," says M. Elisée Reclus, "is an economic scandal. Whilst on dangerous coasts harbours are constructed at vast expense, here we have one that is perfect, and which has been neglected for fifteen centuries." But though the Romans or Greeks had a station here, they did not utilise the lagoon. At S. Chamas are remains of the masters of the ancient world, but no evidence that they had there a naval station.
The line cuts again through the lip of the basin, and we are in the Crau.
At a remote period, but, nevertheless, in one geologically modern, the
vast floods of the diluvial age that flowed from the Alps brought down
incredible quantities of rolled stones, the detritus of the Alps. This
filled up a great bay now occupied by the mouths of the Rhone, and spread
in a triangle from Avignon as the apex, to Cette in the west, and Fos in
the east. This rubble, washed down from the Alps, forms the substratum
of the immense plain that inclines at a very slight angle into the
Mediterranean, and extends for a considerable distance below the sea. Not
only did the Rhone bring down these boulders, but also the Durance, which
enters the Rhone above Arles, and formed between the chain of Les Alpines
and the Luberon another triangular plain of rolled stones, with the apex at
Cavaillon and the base between Tarascon and Avignon. But the Durance did
more. There is a break in the chain on the south, between the limestone
Alpines and the sandstone Trévaresse; and the brimming Durance, unable to
discharge all her water, choked with rubble, into the Rhone, burst through
the open door or natural waste-pipe, by Salon, and carried a portion of her
pebbles into the sea directly, without asking her sister the Rhone to help
her. Now the two great plains formed by the delta of the Rhone, and that
of the Durance into the Rhone, are called the great and little Craus. They
were known to the ancients, and puzzled them not a little. Strabo says of
the Great Crau: "Between Marseilles and the mouth of the Rhone, at about a
hundred stadia from the sea, is a plain, circular in form, and a hundred
stadia in diameter, to which a singular event obtained for it the name of
the Field of Pebbles. It is, in fact, covered with pebbles, as big as the
fist, among which grows some grass in sufficient abundance to pasture herds
of oxen."
Then we are given the legend that accounts for it. Here Hercules fought
against the Ligurians, when the son of Jove, having exhausted his arrows, was supplied with artillery by a discharge of stones from the sky, showered on his enemies by Jupiter.